[PATCH v3 00/21] lib: Rust implementation of SPDM

[PATCH v3 00/21] lib: Rust implementation of SPDM

[alistair23]

From: Alistair Francis <alistair.francis@wdc.com>

Security Protocols and Data Models (SPDM) [1] is used for authentication,
attestation and key exchange. SPDM is generally used over a range of
transports, such as PCIe, MCTP/SMBus/I3C, ATA, SCSI, NVMe or TCP.

From the kernels perspective SPDM is used to authenticate and attest devices.
In this threat model a device is considered untrusted until it can be verified
by the kernel and userspace using SPDM. As such SPDM data is untrusted data
that can be mallicious.

The SPDM specification is also complex, with the 1.2.1 spec being almost 200
pages and the 1.3.0 spec being almost 250 pages long.

As such we have the kernel parsing untrusted responses from a complex
specification, which sounds like a possible exploit vector. This is the type
of place where Rust excels!

This series implements a SPDM requester in Rust.

This is based on Lukas' C implementation [2], but has been refacted during the
first few RFCs. I have included some of the relevent patchesfrom Lukas' C
SPDM implementation in this series where they are required.

This is a standalone series and doesn't depend on Lukas' implementation.

The goal of this series is to get the smallest possible SPDM implementation
upstream. That will provide building blocks for us to continue working on.

As such we don't yet provide evidence or certificates to userspace, allow
userspace to provide a nonce, support PQC or more advanced SPDM features.
This is enough to communicate with a device and return "authenticated" to
userspace.

Note that RFC v3 did provide evidence and certificates to userspace and
allowed a custom nonce. Showing that it's possible. I also have patches
that build apon [4] to do this via a TSM driver, again showing it's
possible with the current approach.
We just don't support it yet and for TSM I need [4] upstream first.

This series is different to Lukas' original approach and the approach taken
in the previous RFCs and instead adds the PCI-CMA support as a TSM driver.
This was described by Dan in [3] and [5]. The advantage here is that for PCIe
we can leverage the TSM work for a lot of the features and provide userspace
a consistient interface between PCI TSM and CMA.

This series also doesn't check the certificate chain against the kernel
keyring and will instead leave that to userspace once [4] is merged.

Other transport mode (such as ATA, SCSI, NVMe and MCTP) will
therefore need slightly different approaches, as TSM doesn't apply.
The library can support this though, it will just need some netlink
and sysfs wrappers added as applicable. This way each transport can support
SPDM in the way it sees fit.

The entire tree can be seen here:
https://github.com/alistair23/linux/tree/alistair/spdm-rust-tsm

I'm testing this by running the following

```shell
cargo run -- --qemu-server response

qemu-system-x86_64 \
  -nic none \
  -object rng-random,filename=/dev/urandom,id=rng0 \
  -device virtio-rng-pci,rng=rng0 \
  -drive file=deploy/images/qemux86-64/core-image-pcie-qemux86-64.rootfs.ext4,if=virtio,format=raw \
  -usb -device usb-tablet -usb -device usb-kbd \
  -cpu Skylake-Client \
  -machine q35,i8042=off \
  -smp 4 -m 2G \
  -drive file=blknvme,if=none,id=mynvme,format=raw \
  -device nvme,drive=mynvme,serial=deadbeef,spdm_port=2323,spdm_trans=doe \
  -snapshot \
  -serial mon:stdio -serial null -nographic \
  -kernel deploy/images/qemux86-64/bzImage \
  -append 'root=/dev/vda rw  console=ttyS0 console=ttyS1 oprofile.timer=1 tsc=reliable no_timer_check rcupdate.rcu_expedited=1 swiotlb=0 '

ls /sys/devices/pci0000:00/0000:00:03.0/
ls /sys/devices/pci0000:00/0000:00:03.0/tsm/
cat  /sys/devices/pci0000:00/0000:00:03.0/authenticated
echo tsm0 > /sys/devices/pci0000:00/0000:00:03.0/tsm/connect
cat  /sys/devices/pci0000:00/0000:00:03.0/authenticated
```

1: https://www.dmtf.org/standards/spdm
2: https://lore.kernel.org/all/cover.1719771133.git.lukas@wunner.de/
3: http://lore.kernel.org/69976d7d39c60_2f4a1009@dwillia2-mobl4.notmuch
4: https://lore.kernel.org/all/69976d7d39c60_2f4a1009@dwillia2-mobl4.notmuch/
5: https://lore.kernel.org/lkml/69e19c80b892b_fe0831000@djbw-dev.notmuch/

v3:
 - Rebase on 7.3-rc1
v2:
 - Tidy up the PCI/TSM function naming and is_pci_tsm_host()
 - A large number of changes (mostly to the Rust code) based on Sashiko reviews
     - This includes a few local runs of Sashiko
     - This has fixed a few undefined behviour bugs in the Rust code
 - Rebase on v4 of Benno's validate patches (patch 1, 2, 3)
v1:
 - Add CMA as a TSM driver
 - Initial support for SPDM 1.4
 - Cleanup a range of comments and concerns from RFC
 - Remove kernel keyring checks
RFC v3:
 - Use netlink to send information to userspace
 - Don't autogenerate Rust helpers
RFC v2:
 - Drop support for Rust and C implementations
 - Include patches from Lukas to reduce series deps
 - Large code cleanups based on more testing
 - Support for authentication

Alistair Francis (14):
  rust: add bindings for hash.h
  rust: error: impl From<FromBytesWithNulError> for Kernel Error
  lib: rspdm: Initial commit of Rust SPDM
  PCI/TSM: Rename pf0 to host
  PCI/TSM: Support connecting to PCIe CMA devices
  PCI/CMA: Add a PCI TSM CMA driver using SPDM
  lib: rspdm: Support SPDM get_version
  lib: rspdm: Support SPDM get_capabilities
  lib: rspdm: Support SPDM negotiate_algorithms
  lib: rspdm: Support SPDM get_digests
  lib: rspdm: Support SPDM get_certificate
  lib: rspdm: Support SPDM certificate validation
  rust: allow extracting the buffer from a CString
  lib: rspdm: Support SPDM challenge

Benno Lossin (3):
  rust: transmute: add `cast_slice[_mut]` functions
  rust: create basic untrusted data API
  rust: validate: add `Validate` trait

Lukas Wunner (4):
  X.509: Make certificate parser public
  X.509: Parse Subject Alternative Name in certificates
  X.509: Move certificate length retrieval into new helper
  PCI/CMA: Validate Subject Alternative Name in certificates

 MAINTAINERS                               |   13 +
 crypto/asymmetric_keys/x509_cert_parser.c |    9 +
 crypto/asymmetric_keys/x509_loader.c      |   38 +-
 crypto/asymmetric_keys/x509_parser.h      |   42 +-
 drivers/crypto/ccp/sev-dev-tio.h          |    4 +-
 drivers/crypto/ccp/sev-dev-tsm.c          |   12 +-
 drivers/pci/Kconfig                       |   14 +
 drivers/pci/Makefile                      |    5 +
 drivers/pci/cma.asn1                      |   41 +
 drivers/pci/cma.c                         |  275 +++++
 drivers/pci/doe.c                         |    6 +-
 drivers/pci/tsm.c                         |  115 +-
 include/keys/asymmetric-type.h            |    2 +
 include/keys/x509-parser.h                |   57 +
 include/linux/oid_registry.h              |    3 +
 include/linux/pci-doe.h                   |    4 +
 include/linux/pci-tsm.h                   |   30 +-
 include/linux/pci.h                       |    1 +
 include/linux/spdm.h                      |   37 +
 lib/Kconfig                               |   15 +
 lib/Makefile                              |    2 +
 lib/rspdm/Makefile                        |   10 +
 lib/rspdm/consts.rs                       |  184 +++
 lib/rspdm/lib.rs                          |  167 +++
 lib/rspdm/state.rs                        | 1230 +++++++++++++++++++++
 lib/rspdm/validator.rs                    |  554 ++++++++++
 rust/bindings/bindings_helper.h           |    5 +
 rust/helpers/hash.c                       |   18 +
 rust/helpers/helpers.c                    |    1 +
 rust/kernel/error.rs                      |   18 +-
 rust/kernel/lib.rs                        |    1 +
 rust/kernel/str.rs                        |   13 +-
 rust/kernel/transmute.rs                  |   59 +
 rust/kernel/validate.rs                   |  216 ++++
 34 files changed, 3071 insertions(+), 130 deletions(-)
 create mode 100644 drivers/pci/cma.asn1
 create mode 100644 drivers/pci/cma.c
 create mode 100644 include/keys/x509-parser.h
 create mode 100644 include/linux/spdm.h
 create mode 100644 lib/rspdm/Makefile
 create mode 100644 lib/rspdm/consts.rs
 create mode 100644 lib/rspdm/lib.rs
 create mode 100644 lib/rspdm/state.rs
 create mode 100644 lib/rspdm/validator.rs
 create mode 100644 rust/helpers/hash.c
 create mode 100644 rust/kernel/validate.rs

-- 
2.55.0

[PATCH v3 01/21] rust: transmute: add `cast_slice[_mut]` functions

[alistair23]

From: Benno Lossin <benno.lossin@proton.me>

Add functions to make casting slices only one `unsafe` block.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Message-ID: <20250814124424.516191-2-lossin@kernel.org>
---
 rust/kernel/transmute.rs | 59 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/rust/kernel/transmute.rs b/rust/kernel/transmute.rs
index 654b5ede2fe2..c1282fcc9e65 100644
--- a/rust/kernel/transmute.rs
+++ b/rust/kernel/transmute.rs
@@ -3,6 +3,7 @@
 //! Traits for transmuting types.
 
 use core::mem::size_of;
+use core::slice;
 
 /// Types for which any bit pattern is valid.
 ///
@@ -227,3 +228,61 @@ macro_rules! impl_asbytes {
     {<T: AsBytes>} [T],
     {<T: AsBytes, const N: usize>} [T; N],
 }
+
+/// Casts the type of a slice to another.
+///
+/// Also see [`cast_slice_mut`].
+///
+/// # Examples
+///
+/// ```rust
+/// # use kernel::transmute::cast_slice;
+/// #[repr(transparent)]
+/// #[derive(Debug)]
+/// struct Container<T>(T);
+///
+/// let array = [0u32; 42];
+/// let slice = &array;
+/// // SAFETY: `Container<u32>` transparently wraps a `u32`.
+/// let container_slice = unsafe { cast_slice::<u32, Container<u32>>(slice) };
+/// pr_info!("{container_slice:?}");
+/// ```
+///
+/// # Safety
+///
+/// - `T` and `U` must have the same layout.
+pub unsafe fn cast_slice<T, U>(slice: &[T]) -> &[U] {
+    // CAST: by the safety requirements, `T` and `U` have the same layout.
+    let ptr = slice.as_ptr().cast::<U>();
+    // SAFETY: `ptr` and `len` come from the same slice reference.
+    unsafe { slice::from_raw_parts(ptr, slice.len()) }
+}
+
+/// Casts the type of a slice to another.
+///
+/// Also see [`cast_slice`].
+///
+/// # Examples
+///
+/// ```rust
+/// # use kernel::transmute::cast_slice_mut;
+/// #[repr(transparent)]
+/// #[derive(Debug)]
+/// struct Container<T>(T);
+///
+/// let mut array = [0u32; 42];
+/// let slice = &mut array;
+/// // SAFETY: `Container<u32>` transparently wraps a `u32`.
+/// let container_slice = unsafe { cast_slice_mut::<u32, Container<u32>>(slice) };
+/// pr_info!("{container_slice:?}");
+/// ```
+///
+/// # Safety
+///
+/// - `T` and `U` must have the same layout.
+pub unsafe fn cast_slice_mut<T, U>(slice: &mut [T]) -> &mut [U] {
+    // CAST: by the safety requirements, `T` and `U` have the same layout.
+    let ptr = slice.as_mut_ptr().cast::<U>();
+    // SAFETY: `ptr` and `len` come from the same slice reference.
+    unsafe { slice::from_raw_parts_mut(ptr, slice.len()) }
+}
-- 
2.55.0

[PATCH v3 02/21] rust: create basic untrusted data API

[alistair23]

From: Benno Lossin <benno.lossin@proton.me>

When the kernel receives external data (e.g. from userspace), it usually
is a very bad idea to directly use the data for logic decision in the
kernel. For this reason, such data should be explicitly marked and
validated before making decision based on its value.

The `Untrusted<T>` wrapper type marks a value of type `T` as untrusted.
The particular meaning of "untrusted" highly depends on the type `T`.
For example `T = u8` ensures that the value of the byte cannot be
retrieved. However, `T = [u8]` still allows to access the length of the
slice. Similarly, `T = KVec<U>` allows modifications.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Message-ID: <20250814124424.516191-3-lossin@kernel.org>
---
 rust/kernel/lib.rs      |   1 +
 rust/kernel/validate.rs | 148 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 149 insertions(+)
 create mode 100644 rust/kernel/validate.rs

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 4d5c96ddc49c..239f8325b40a 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -143,6 +143,7 @@
 pub mod uaccess;
 #[cfg(CONFIG_USB = "y")]
 pub mod usb;
+pub mod validate;
 pub mod workqueue;
 pub mod xarray;
 
diff --git a/rust/kernel/validate.rs b/rust/kernel/validate.rs
new file mode 100644
index 000000000000..2b28625c25ef
--- /dev/null
+++ b/rust/kernel/validate.rs
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Untrusted data API.
+//!
+//! # Overview
+//!
+//! Untrusted data is marked using the [`Untrusted<T>`] type. See [Rationale](#rationale) for the
+//! reasons to mark untrusted data throughout the kernel. It is a totally opaque wrapper, it is not
+//! possible to read the data inside.
+//!
+//! APIs that write back into userspace usually allow writing untrusted bytes directly, allowing
+//! direct copying of untrusted user data back into userspace without validation.
+//!
+//! # Rationale
+//!
+//! When reading data from an untrusted source, it must be validated before it can be used for
+//! **logic**. For example, this is a very bad idea:
+//!
+//! ```
+//! # fn read_bytes_from_network() -> KBox<[u8]> {
+//! #     Box::new([1, 0], kernel::alloc::flags::GFP_KERNEL).unwrap()
+//! # }
+//! let bytes: KBox<[u8]> = read_bytes_from_network();
+//! let data_index = bytes[0];
+//! let data = bytes[usize::from(data_index)];
+//! ```
+//!
+//! While this will not lead to a memory violation (because the array index checks the bounds), it
+//! might result in a kernel panic. For this reason, all untrusted data must be wrapped in
+//! [`Untrusted<T>`]. This type only allows validating the data or passing it along, since copying
+//! data from userspace back into userspace is allowed for untrusted data.
+
+use core::ops::{Deref, DerefMut};
+
+use crate::{
+    alloc::{
+        Allocator,
+        Vec, //
+    },
+    transmute::{
+        cast_slice,
+        cast_slice_mut, //
+    },
+};
+
+/// Untrusted data of type `T`.
+///
+/// Data coming from userspace is considered untrusted and should be marked by this type.
+///
+/// The particular meaning of [`Untrusted<T>`] depends heavily on the type `T`. For example,
+/// `&Untrusted<[u8]>` is a reference to an untrusted slice. But the length is not considered
+/// untrusted, as it would otherwise violate normal Rust rules. For this reason, one can easily
+/// convert that reference to `&[Untrusted<u8>]`. Another such example is `Untrusted<KVec<T>>`, it
+/// derefs to `KVec<Untrusted<T>>`. Raw bytes however do not behave in this way, `Untrusted<u8>` is
+/// totally opaque.
+///
+/// # Usage in API Design
+///
+/// The exact location where to put [`Untrusted`] depends on the kind of API. When asking for an
+/// untrusted input value, or buffer to write to, always move the [`Untrusted`] wrapper as far
+/// inwards as possible:
+///
+/// ```ignore
+/// // use this
+/// pub fn read_from_userspace(buf: &mut [Untrusted<u8>]) { todo!() }
+///
+/// // and not this
+/// pub fn read_from_userspace(buf: &mut Untrusted<[u8]>) { todo!() }
+/// ```
+///
+/// The reason for this is that `&mut Untrusted<[u8]>` can beconverted into `&mut [Untrusted<u8>]`
+/// very easily, but the converse is not possible.
+///
+/// For the same reason, when returning untrusted data by-value, one should move the [`Untrusted`]
+/// wrapper as far outward as possible:
+///
+/// ```ignore
+/// // use this
+/// pub fn read_all_from_userspace() -> Untrusted<KVec<u8>> { todo!() }
+///
+/// // and not this
+/// pub fn read_all_from_userspace() -> KVec<Untrusted<u8>> { todo!() }
+/// ```
+///
+/// Here too the reason is that `KVec<Untrusted<u8>>` is more restrictive compared to
+/// `Untrusted<KVec<u8>>`.
+#[repr(transparent)]
+pub struct Untrusted<T: ?Sized>(T);
+
+impl<T: ?Sized> Untrusted<T> {
+    /// Marks the given value as untrusted.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::validate::Untrusted;
+    ///
+    /// # mod bindings { pub(crate) unsafe fn read_foo_info() -> [u8; 4] { todo!() } };
+    /// fn read_foo_info() -> Untrusted<[u8; 4]> {
+    ///     // SAFETY: just an FFI call without preconditions.
+    ///     Untrusted::new(unsafe { bindings::read_foo_info() })
+    /// }
+    /// ```
+    pub fn new(value: T) -> Self
+    where
+        T: Sized,
+    {
+        Self(value)
+    }
+}
+
+impl<T> Deref for Untrusted<[T]> {
+    type Target = [Untrusted<T>];
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: `Untrusted<T>` transparently wraps `T`.
+        unsafe { cast_slice(&self.0) }
+    }
+}
+
+impl<T> DerefMut for Untrusted<[T]> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        // SAFETY: `Untrusted<T>` transparently wraps `T`.
+        unsafe { cast_slice_mut(&mut self.0) }
+    }
+}
+
+impl<T, A: Allocator> Deref for Untrusted<Vec<T, A>> {
+    type Target = Vec<Untrusted<T>, A>;
+
+    fn deref(&self) -> &Self::Target {
+        let ptr: *const Untrusted<Vec<T, A>> = self;
+        // CAST: `Untrusted<T>` transparently wraps `T`.
+        let ptr: *const Vec<Untrusted<T>, A> = ptr.cast();
+        // SAFETY: `ptr` is derived from the reference `self`.
+        unsafe { &*ptr }
+    }
+}
+
+impl<T, A: Allocator> DerefMut for Untrusted<Vec<T, A>> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        let ptr: *mut Untrusted<Vec<T, A>> = self;
+        // CAST: `Untrusted<T>` transparently wraps `T`.
+        let ptr: *mut Vec<Untrusted<T>, A> = ptr.cast();
+        // SAFETY: `ptr` is derived from the reference `self`.
+        unsafe { &mut *ptr }
+    }
+}
-- 
2.55.0

[PATCH v3 03/21] rust: validate: add `Validate` trait

[alistair23]

From: Benno Lossin <benno.lossin@proton.me>

Introduce the `Validate<Input>` trait and functions to validate
`Untrusted<T>` using said trait. This allows one to access the inner
value of `Untrusted<T>` via `validate{,_ref,_mut}` functions which
subsequently delegate the validation to user-implemented `Validate`
trait.

The `Validate` trait is the only entry point for validation code, making
it easy to spot where data is being validated.

The reason for restricting the types that can be inputs to
`Validate::validate` is to be able to have the `validate...` functions
on `Untrusted`. This is also the reason for the suggestions in the
`Usage in API Design` section in the commit that introduced
`Untrusted<T>`.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Message-ID: <20250814124424.516191-4-lossin@kernel.org>
---
 rust/kernel/validate.rs | 70 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/rust/kernel/validate.rs b/rust/kernel/validate.rs
index 2b28625c25ef..663681b633c8 100644
--- a/rust/kernel/validate.rs
+++ b/rust/kernel/validate.rs
@@ -11,6 +11,9 @@
 //! APIs that write back into userspace usually allow writing untrusted bytes directly, allowing
 //! direct copying of untrusted user data back into userspace without validation.
 //!
+//! The only way to access untrusted data is to [`Validate::validate`] it. This is facilitated by
+//! the [`Validate`] trait.
+//!
 //! # Rationale
 //!
 //! When reading data from an untrusted source, it must be validated before it can be used for
@@ -52,7 +55,7 @@
 /// untrusted, as it would otherwise violate normal Rust rules. For this reason, one can easily
 /// convert that reference to `&[Untrusted<u8>]`. Another such example is `Untrusted<KVec<T>>`, it
 /// derefs to `KVec<Untrusted<T>>`. Raw bytes however do not behave in this way, `Untrusted<u8>` is
-/// totally opaque.
+/// totally opaque and one can only access its value by calling [`Untrusted::validate()`].
 ///
 /// # Usage in API Design
 ///
@@ -107,6 +110,30 @@ pub fn new(value: T) -> Self
     {
         Self(value)
     }
+
+    /// Validate the underlying untrusted data.
+    ///
+    /// See the [`Validate`] trait for more information.
+    pub fn validate<V: Validate<Self>>(self) -> Result<V, V::Err>
+    where
+        T: Sized,
+    {
+        V::validate(self.0)
+    }
+
+    /// Validate the underlying untrusted data.
+    ///
+    /// See the [`Validate`] trait for more information.
+    pub fn validate_ref<'a, V: Validate<&'a Self>>(&'a self) -> Result<V, V::Err> {
+        V::validate(&self.0)
+    }
+
+    /// Validate the underlying untrusted data.
+    ///
+    /// See the [`Validate`] trait for more information.
+    pub fn validate_mut<'a, V: Validate<&'a mut Self>>(&'a mut self) -> Result<V, V::Err> {
+        V::validate(&mut self.0)
+    }
 }
 
 impl<T> Deref for Untrusted<[T]> {
@@ -146,3 +173,44 @@ fn deref_mut(&mut self) -> &mut Self::Target {
         unsafe { &mut *ptr }
     }
 }
+
+/// Marks valid input for the [`Validate`] trait.
+pub trait ValidateInput: private::Sealed {
+    /// Type of the inner data.
+    type Inner: ?Sized;
+}
+
+impl<T: ?Sized> ValidateInput for Untrusted<T> {
+    type Inner = T;
+}
+
+impl<'a, T: ?Sized> ValidateInput for &'a Untrusted<T> {
+    type Inner = &'a T;
+}
+
+impl<'a, T: ?Sized> ValidateInput for &'a mut Untrusted<T> {
+    type Inner = &'a mut T;
+}
+
+mod private {
+    use super::Untrusted;
+
+    pub trait Sealed {}
+
+    impl<T: ?Sized> Sealed for Untrusted<T> {}
+    impl<'a, T: ?Sized> Sealed for &'a Untrusted<T> {}
+    impl<'a, T: ?Sized> Sealed for &'a mut Untrusted<T> {}
+}
+
+/// Validate [`Untrusted`] data.
+///
+/// Care must be taken when implementing this trait, as unprotected access to unvalidated data is
+/// given to the [`Validate::validate`] function. The implementer must ensure that the data is only
+/// used for logic after successful validation.
+pub trait Validate<Input: ValidateInput>: Sized {
+    /// Validation error.
+    type Err;
+
+    /// Validate the raw input.
+    fn validate(raw: Input::Inner) -> Result<Self, Self::Err>;
+}
-- 
2.55.0

[PATCH v3 04/21] X.509: Make certificate parser public

[alistair23]

From: Lukas Wunner <lukas@wunner.de>

The upcoming support for PCI device authentication with CMA-SPDM
(PCIe r6.1 sec 6.31) requires validating the Subject Alternative Name
in X.509 certificates.

High-level functions for X.509 parsing such as key_create_or_update()
throw away the internal, low-level struct x509_certificate after
extracting the struct public_key and public_key_signature from it.
The Subject Alternative Name is thus inaccessible when using those
functions.

Afford CMA-SPDM access to the Subject Alternative Name by making struct
x509_certificate public, together with the functions for parsing an
X.509 certificate into such a struct and freeing such a struct.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 crypto/asymmetric_keys/x509_parser.h | 42 +--------------------
 include/keys/x509-parser.h           | 55 ++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 41 deletions(-)
 create mode 100644 include/keys/x509-parser.h

diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h
index b7aeebdddb36..39f1521b773d 100644
--- a/crypto/asymmetric_keys/x509_parser.h
+++ b/crypto/asymmetric_keys/x509_parser.h
@@ -5,51 +5,11 @@
  * Written by David Howells (dhowells@redhat.com)
  */
 
-#include <linux/cleanup.h>
-#include <linux/time.h>
-#include <crypto/public_key.h>
-#include <keys/asymmetric-type.h>
-#include <crypto/sha2.h>
-
-struct x509_certificate {
-	struct x509_certificate *next;
-	struct x509_certificate *signer;	/* Certificate that signed this one */
-	struct public_key *pub;			/* Public key details */
-	struct public_key_signature *sig;	/* Signature parameters */
-	u8		sha256[SHA256_DIGEST_SIZE]; /* Hash for blacklist purposes */
-	char		*issuer;		/* Name of certificate issuer */
-	char		*subject;		/* Name of certificate subject */
-	struct asymmetric_key_id *id;		/* Issuer + Serial number */
-	struct asymmetric_key_id *skid;		/* Subject + subjectKeyId (optional) */
-	time64_t	valid_from;
-	time64_t	valid_to;
-	const void	*tbs;			/* Signed data */
-	unsigned	tbs_size;		/* Size of signed data */
-	unsigned	raw_sig_size;		/* Size of signature */
-	const void	*raw_sig;		/* Signature data */
-	const void	*raw_serial;		/* Raw serial number in ASN.1 */
-	unsigned	raw_serial_size;
-	unsigned	raw_issuer_size;
-	const void	*raw_issuer;		/* Raw issuer name in ASN.1 */
-	const void	*raw_subject;		/* Raw subject name in ASN.1 */
-	unsigned	raw_subject_size;
-	unsigned	raw_skid_size;
-	const void	*raw_skid;		/* Raw subjectKeyId in ASN.1 */
-	unsigned	index;
-	bool		seen;			/* Infinite recursion prevention */
-	bool		verified;
-	bool		self_signed;		/* T if self-signed (check unsupported_sig too) */
-	bool		unsupported_sig;	/* T if signature uses unsupported crypto */
-	bool		blacklisted;
-};
+#include <keys/x509-parser.h>
 
 /*
  * x509_cert_parser.c
  */
-extern void x509_free_certificate(struct x509_certificate *cert);
-DEFINE_FREE(x509_free_certificate, struct x509_certificate *,
-	    if (!IS_ERR(_T)) x509_free_certificate(_T))
-extern struct x509_certificate *x509_cert_parse(const void *data, size_t datalen);
 extern int x509_decode_time(time64_t *_t,  size_t hdrlen,
 			    unsigned char tag,
 			    const unsigned char *value, size_t vlen);
diff --git a/include/keys/x509-parser.h b/include/keys/x509-parser.h
new file mode 100644
index 000000000000..8b68e720693a
--- /dev/null
+++ b/include/keys/x509-parser.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* X.509 certificate parser
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifndef _KEYS_X509_PARSER_H
+#define _KEYS_X509_PARSER_H
+
+#include <linux/cleanup.h>
+#include <linux/time.h>
+#include <crypto/public_key.h>
+#include <keys/asymmetric-type.h>
+#include <crypto/sha2.h>
+
+struct x509_certificate {
+	struct x509_certificate *next;
+	struct x509_certificate *signer;	/* Certificate that signed this one */
+	struct public_key *pub;			/* Public key details */
+	struct public_key_signature *sig;	/* Signature parameters */
+	u8		sha256[SHA256_DIGEST_SIZE]; /* Hash for blacklist purposes */
+	char		*issuer;		/* Name of certificate issuer */
+	char		*subject;		/* Name of certificate subject */
+	struct asymmetric_key_id *id;		/* Issuer + Serial number */
+	struct asymmetric_key_id *skid;		/* Subject + subjectKeyId (optional) */
+	time64_t	valid_from;
+	time64_t	valid_to;
+	const void	*tbs;			/* Signed data */
+	unsigned	tbs_size;		/* Size of signed data */
+	unsigned	raw_sig_size;		/* Size of signature */
+	const void	*raw_sig;		/* Signature data */
+	const void	*raw_serial;		/* Raw serial number in ASN.1 */
+	unsigned	raw_serial_size;
+	unsigned	raw_issuer_size;
+	const void	*raw_issuer;		/* Raw issuer name in ASN.1 */
+	const void	*raw_subject;		/* Raw subject name in ASN.1 */
+	unsigned	raw_subject_size;
+	unsigned	raw_skid_size;
+	const void	*raw_skid;		/* Raw subjectKeyId in ASN.1 */
+	unsigned	index;
+	bool		seen;			/* Infinite recursion prevention */
+	bool		verified;
+	bool		self_signed;		/* T if self-signed (check unsupported_sig too) */
+	bool		unsupported_sig;	/* T if signature uses unsupported crypto */
+	bool		blacklisted;
+};
+
+struct x509_certificate *x509_cert_parse(const void *data, size_t datalen);
+void x509_free_certificate(struct x509_certificate *cert);
+
+DEFINE_FREE(x509_free_certificate, struct x509_certificate *,
+	    if (!IS_ERR(_T)) x509_free_certificate(_T))
+
+#endif /* _KEYS_X509_PARSER_H */
-- 
2.55.0

[PATCH v3 05/21] X.509: Parse Subject Alternative Name in certificates

[alistair23]

From: Lukas Wunner <lukas@wunner.de>

The upcoming support for PCI device authentication with CMA-SPDM
(PCIe r6.1 sec 6.31) requires validating the Subject Alternative Name
in X.509 certificates.

Store a pointer to the Subject Alternative Name upon parsing for
consumption by CMA-SPDM.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
---
 crypto/asymmetric_keys/x509_cert_parser.c | 9 +++++++++
 include/keys/x509-parser.h                | 2 ++
 2 files changed, 11 insertions(+)

diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index bfd10f0195e0..c3ec2846695a 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -596,6 +596,15 @@ int x509_process_extension(void *context, size_t hdrlen,
 		return 0;
 	}
 
+	if (ctx->last_oid == OID_subjectAltName) {
+		if (ctx->cert->raw_san)
+			return -EBADMSG;
+
+		ctx->cert->raw_san = v;
+		ctx->cert->raw_san_size = vlen;
+		return 0;
+	}
+
 	if (ctx->last_oid == OID_keyUsage) {
 		/*
 		 * Get hold of the keyUsage bit string
diff --git a/include/keys/x509-parser.h b/include/keys/x509-parser.h
index 8b68e720693a..4e6a05a8c7a6 100644
--- a/include/keys/x509-parser.h
+++ b/include/keys/x509-parser.h
@@ -38,6 +38,8 @@ struct x509_certificate {
 	unsigned	raw_subject_size;
 	unsigned	raw_skid_size;
 	const void	*raw_skid;		/* Raw subjectKeyId in ASN.1 */
+	const void	*raw_san;		/* Raw subjectAltName in ASN.1 */
+	unsigned	raw_san_size;
 	unsigned	index;
 	bool		seen;			/* Infinite recursion prevention */
 	bool		verified;
-- 
2.55.0

[PATCH v3 06/21] X.509: Move certificate length retrieval into new helper

[alistair23]

From: Lukas Wunner <lukas@wunner.de>

The upcoming in-kernel SPDM library (Security Protocol and Data Model,
https://www.dmtf.org/dsp/DSP0274) needs to retrieve the length from
ASN.1 DER-encoded X.509 certificates.

Such code already exists in x509_load_certificate_list(), so move it
into a new helper for reuse by SPDM.

Export the helper so that SPDM can be tristate.  (Some upcoming users of
the SPDM libray may be modular, such as SCSI and ATA.)

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 crypto/asymmetric_keys/x509_loader.c | 38 +++++++++++++++++++---------
 include/keys/asymmetric-type.h       |  2 ++
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/crypto/asymmetric_keys/x509_loader.c b/crypto/asymmetric_keys/x509_loader.c
index 0d516c77cc26..174451b93eda 100644
--- a/crypto/asymmetric_keys/x509_loader.c
+++ b/crypto/asymmetric_keys/x509_loader.c
@@ -4,28 +4,42 @@
 #include <linux/key.h>
 #include <keys/asymmetric-type.h>
 
+ssize_t x509_get_certificate_length(const u8 *p, unsigned long buflen)
+{
+	ssize_t plen;
+
+	/* Each cert begins with an ASN.1 SEQUENCE tag and must be more
+	 * than 256 bytes in size.
+	 */
+	if (buflen < 4)
+		return -EINVAL;
+
+	if (p[0] != 0x30 ||
+	    p[1] != 0x82)
+		return -EINVAL;
+
+	plen = (p[2] << 8) | p[3];
+	plen += 4;
+	if (plen > buflen)
+		return -EINVAL;
+
+	return plen;
+}
+EXPORT_SYMBOL_GPL(x509_get_certificate_length);
+
 int x509_load_certificate_list(const u8 cert_list[],
 			       const unsigned long list_size,
 			       const struct key *keyring)
 {
 	key_ref_t key;
 	const u8 *p, *end;
-	size_t plen;
+	ssize_t plen;
 
 	p = cert_list;
 	end = p + list_size;
 	while (p < end) {
-		/* Each cert begins with an ASN.1 SEQUENCE tag and must be more
-		 * than 256 bytes in size.
-		 */
-		if (end - p < 4)
-			goto dodgy_cert;
-		if (p[0] != 0x30 ||
-		    p[1] != 0x82)
-			goto dodgy_cert;
-		plen = (p[2] << 8) | p[3];
-		plen += 4;
-		if (plen > end - p)
+		plen = x509_get_certificate_length(p, end - p);
+		if (plen < 0)
 			goto dodgy_cert;
 
 		key = key_create_or_update(make_key_ref(keyring, 1),
diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h
index 1b91c8f98688..301efa952e26 100644
--- a/include/keys/asymmetric-type.h
+++ b/include/keys/asymmetric-type.h
@@ -84,6 +84,8 @@ extern struct key *find_asymmetric_key(struct key *keyring,
 				       const struct asymmetric_key_id *id_2,
 				       bool partial);
 
+ssize_t x509_get_certificate_length(const u8 *p, unsigned long buflen);
+
 int x509_load_certificate_list(const u8 cert_list[], const unsigned long list_size,
 			       const struct key *keyring);
 
-- 
2.55.0

[PATCH v3 07/21] rust: add bindings for hash.h

[alistair23]

From: Alistair Francis <alistair.francis@wdc.com>

Make the functions crypto_shash_descsize(), crypto_shash_digestsize()
and crypto_free_shash() available to Rust.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 rust/bindings/bindings_helper.h |  1 +
 rust/helpers/hash.c             | 18 ++++++++++++++++++
 rust/helpers/helpers.c          |  1 +
 3 files changed, 20 insertions(+)
 create mode 100644 rust/helpers/hash.c

diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 4b31aa7f432f..fd223b6c5aaf 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -30,6 +30,7 @@
 
 #include <linux/acpi.h>
 #include <linux/gpu_buddy.h>
+#include <crypto/hash.h>
 #include <drm/drm_device.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
diff --git a/rust/helpers/hash.c b/rust/helpers/hash.c
new file mode 100644
index 000000000000..23a63618a370
--- /dev/null
+++ b/rust/helpers/hash.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <crypto/hash.h>
+
+__rust_helper unsigned int rust_helper_crypto_shash_descsize(struct crypto_shash *tfm)
+{
+	return crypto_shash_descsize(tfm);
+}
+
+__rust_helper unsigned int rust_helper_crypto_shash_digestsize(struct crypto_shash *tfm)
+{
+	return crypto_shash_digestsize(tfm);
+}
+
+__rust_helper void rust_helper_crypto_free_shash(struct crypto_shash *tfm)
+{
+	crypto_free_shash(tfm);
+}
diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 440fb7638e3c..09ec69f736b1 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -66,6 +66,7 @@
 #include "fs.c"
 #include "fwctl.c"
 #include "gpu.c"
+#include "hash.c"
 #include "interrupt.c"
 #include "io.c"
 #include "irq.c"
-- 
2.55.0

[PATCH v3 08/21] rust: error: impl From<FromBytesWithNulError> for Kernel Error

[alistair23]

From: Alistair Francis <alistair.francis@wdc.com>

Implement From<FromBytesWithNulError> for the Kernel Error type as we
will use it in a future patch.

As this is now generally available we can remove it from the test case
as well.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 rust/kernel/error.rs | 18 +++++++++++++++---
 rust/kernel/str.rs   |  7 -------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index e52793f77196..84e6466f54c2 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -12,9 +12,14 @@
     str::CStr,
 };
 
-use core::num::NonZeroI32;
-use core::num::TryFromIntError;
-use core::str::Utf8Error;
+use core::{
+    ffi::FromBytesWithNulError,
+    num::{
+        NonZeroI32,
+        TryFromIntError, //
+    },
+    str::Utf8Error, //
+};
 
 /// Contains the C-compatible error codes.
 #[rustfmt::skip]
@@ -358,6 +363,13 @@ fn from(e: core::convert::Infallible) -> Error {
     }
 }
 
+impl From<FromBytesWithNulError> for Error {
+    #[inline]
+    fn from(_: FromBytesWithNulError) -> Error {
+        code::EINVAL
+    }
+}
+
 /// A [`Result`] with an [`Error`] error type.
 ///
 /// To be used as the return type for functions that may fail.
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index b3caa9a1c898..a556788bcc5e 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -433,13 +433,6 @@ macro_rules! c_str {
 mod tests {
     use super::*;
 
-    impl From<core::ffi::FromBytesWithNulError> for Error {
-        #[inline]
-        fn from(_: core::ffi::FromBytesWithNulError) -> Error {
-            EINVAL
-        }
-    }
-
     macro_rules! format {
         ($($f:tt)*) => ({
             CString::try_from_fmt(fmt!($($f)*))?.to_str()?
-- 
2.55.0

[PATCH v3 09/21] lib: rspdm: Initial commit of Rust SPDM

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

This is the initial commit of the Rust SPDM library.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 MAINTAINERS                     |  12 ++
 include/linux/spdm.h            |  37 +++++
 lib/Kconfig                     |  15 ++
 lib/Makefile                    |   2 +
 lib/rspdm/Makefile              |  10 ++
 lib/rspdm/consts.rs             |  92 +++++++++++++
 lib/rspdm/lib.rs                |  89 ++++++++++++
 lib/rspdm/state.rs              | 237 ++++++++++++++++++++++++++++++++
 lib/rspdm/validator.rs          |  92 +++++++++++++
 rust/bindings/bindings_helper.h |   1 +
 10 files changed, 587 insertions(+)
 create mode 100644 include/linux/spdm.h
 create mode 100644 lib/rspdm/Makefile
 create mode 100644 lib/rspdm/consts.rs
 create mode 100644 lib/rspdm/lib.rs
 create mode 100644 lib/rspdm/state.rs
 create mode 100644 lib/rspdm/validator.rs

diff --git a/MAINTAINERS b/MAINTAINERS
index 3a19da74d00c..36f84a02894b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -24753,6 +24753,18 @@ M:	Security Officers <security@kernel.org>
 S:	Supported
 F:	Documentation/process/security-bugs.rst
 
+SECURITY PROTOCOL AND DATA MODEL (SPDM)
+M:	Jonathan Cameron <jic23@kernel.org>
+M:	Lukas Wunner <lukas@wunner.de>
+M:	Alistair Francis <alistair@alistair23.me>
+L:	linux-coco@lists.linux.dev
+L:	linux-cxl@vger.kernel.org
+L:	linux-pci@vger.kernel.org
+S:	Maintained
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/devsec/spdm.git
+F:	include/linux/spdm.h
+F:	lib/rspdm/
+
 SECURITY SUBSYSTEM
 M:	Paul Moore <paul@paul-moore.com>
 M:	James Morris <jmorris@namei.org>
diff --git a/include/linux/spdm.h b/include/linux/spdm.h
new file mode 100644
index 000000000000..1f7207b584a8
--- /dev/null
+++ b/include/linux/spdm.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * DMTF Security Protocol and Data Model (SPDM)
+ * https://www.dmtf.org/dsp/DSP0274
+ *
+ * Copyright (C) 2021-22 Huawei
+ *     Jonathan Cameron <Jonathan.Cameron@huawei.com>
+ *
+ * Copyright (C) 2022-24 Intel Corporation
+ */
+
+#ifndef _SPDM_H_
+#define _SPDM_H_
+
+#include <linux/types.h>
+
+struct key;
+struct device;
+struct spdm_state;
+struct x509_certificate;
+
+typedef int (spdm_transport)(void *priv, struct device *dev,
+			     const void *request, size_t request_sz,
+			     void *response, size_t response_sz);
+
+typedef int (spdm_validate)(struct device *dev, u8 slot,
+			    struct x509_certificate *leaf_cert);
+
+struct spdm_state *spdm_create(struct device *dev, spdm_transport *transport,
+			       void *transport_priv, u32 transport_sz,
+			       spdm_validate *validate);
+
+int spdm_authenticate(struct spdm_state *spdm_state);
+
+void spdm_destroy(struct spdm_state *spdm_state);
+
+#endif
diff --git a/lib/Kconfig b/lib/Kconfig
index 4e6b34c3346d..b1792db6ddf0 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -588,6 +588,21 @@ config LWQ_TEST
 	help
 	  Run boot-time test of light-weight queuing.
 
+config RSPDM
+	bool "Rust SPDM"
+	depends on RUST
+	select ASYMMETRIC_KEY_TYPE
+	select CRYPTO
+	select X509_CERTIFICATE_PARSER
+	help
+	  The Rust implementation of the Security Protocol and Data Model (SPDM)
+	  allows for device authentication, measurement, key exchange and
+	  encrypted sessions.
+
+	  Crypto algorithms negotiated with SPDM are limited to those enabled
+	  in .config.  Users of SPDM therefore need to also select
+	  any algorithms they deem mandatory.
+
 endmenu
 
 config GENERIC_IOREMAP
diff --git a/lib/Makefile b/lib/Makefile
index dfab958327c5..22776b7e9416 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -297,6 +297,8 @@ obj-$(CONFIG_PERCPU_TEST) += percpu_test.o
 obj-$(CONFIG_ASN1) += asn1_decoder.o
 obj-$(CONFIG_ASN1_ENCODER) += asn1_encoder.o
 
+obj-$(CONFIG_RSPDM) += rspdm/
+
 obj-$(CONFIG_FONT_SUPPORT) += fonts/
 
 #
diff --git a/lib/rspdm/Makefile b/lib/rspdm/Makefile
new file mode 100644
index 000000000000..1f62ee2a882d
--- /dev/null
+++ b/lib/rspdm/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Rust implementation of the DMTF Security Protocol and Data Model (SPDM)
+# https://www.dmtf.org/dsp/DSP0274
+#
+# Copyright (C) 2024 Western Digital
+
+obj-$(CONFIG_RSPDM) += spdm.o
+
+spdm-y := lib.o
diff --git a/lib/rspdm/consts.rs b/lib/rspdm/consts.rs
new file mode 100644
index 000000000000..01f008958a1f
--- /dev/null
+++ b/lib/rspdm/consts.rs
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 Western Digital
+
+//! Constants used by the library
+//!
+//! Rust implementation of the DMTF Security Protocol and Data Model (SPDM)
+//! <https://www.dmtf.org/dsp/DSP0274>
+
+use kernel::error::{code::EINVAL, Error};
+
+// SPDM versions supported by this implementation
+pub(crate) const SPDM_VER_10: u8 = 0x10;
+
+pub(crate) const SPDM_MIN_VER: u8 = SPDM_VER_10;
+
+#[allow(dead_code)]
+pub(crate) const SPDM_REQ: u8 = 0x80;
+#[allow(dead_code)]
+pub(crate) const SPDM_ERROR: u8 = 0x7f;
+
+#[derive(Clone, Copy)]
+#[repr(u8)]
+pub(crate) enum SpdmErrorCode {
+    InvalidRequest = 0x01,
+    /// This was removed in version 1.2.0 and is now reserved
+    InvalidSession = 0x02,
+    Busy = 0x03,
+    UnexpectedRequest = 0x04,
+    Unspecified = 0x05,
+    DecryptError = 0x06,
+    UnsupportedRequest = 0x07,
+    RequestInFlight = 0x08,
+    InvalidResponseCode = 0x09,
+    SessionLimitExceeded = 0x0a,
+    SessionRequired = 0x0b,
+    ResetRequired = 0x0c,
+    ResponseTooLarge = 0x0d,
+    RequestTooLarge = 0x0e,
+    LargeResponse = 0x0f,
+    MessageLost = 0x10,
+    InvalidPolicy = 0x11,
+    VersionMismatch = 0x41,
+    ResponseNotReady = 0x42,
+    RequestResynch = 0x43,
+    OperationFailed = 0x44,
+    NoPendingRequests = 0x45,
+    RequestSessionTerminated = 0x46,
+    InvalidState = 0x47,
+    VendorDefinedError = 0xff,
+}
+
+impl TryFrom<u8> for SpdmErrorCode {
+    type Error = Error;
+
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
+        Ok(match value {
+            0x01 => Self::InvalidRequest,
+            0x02 => Self::InvalidSession,
+            0x03 => Self::Busy,
+            0x04 => Self::UnexpectedRequest,
+            0x05 => Self::Unspecified,
+            0x06 => Self::DecryptError,
+            0x07 => Self::UnsupportedRequest,
+            0x08 => Self::RequestInFlight,
+            0x09 => Self::InvalidResponseCode,
+            0x0a => Self::SessionLimitExceeded,
+            0x0b => Self::SessionRequired,
+            0x0c => Self::ResetRequired,
+            0x0d => Self::ResponseTooLarge,
+            0x0e => Self::RequestTooLarge,
+            0x0f => Self::LargeResponse,
+            0x10 => Self::MessageLost,
+            0x11 => Self::InvalidPolicy,
+            0x41 => Self::VersionMismatch,
+            0x42 => Self::ResponseNotReady,
+            0x43 => Self::RequestResynch,
+            0x44 => Self::OperationFailed,
+            0x45 => Self::NoPendingRequests,
+            0x46 => Self::RequestSessionTerminated,
+            0x47 => Self::InvalidState,
+            0xff => Self::VendorDefinedError,
+            _ => return Err(EINVAL),
+        })
+    }
+}
+
+impl core::fmt::LowerHex for SpdmErrorCode {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "{:#x}", *self as u8)
+    }
+}
diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
new file mode 100644
index 000000000000..1883579b817a
--- /dev/null
+++ b/lib/rspdm/lib.rs
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 Western Digital
+
+//! Top level library for SPDM
+//!
+//! Rust implementation of the DMTF Security Protocol and Data Model (SPDM)
+//! <https://www.dmtf.org/dsp/DSP0274>
+//!
+//! Top level library, including C compatible public functions to be called
+//! from other subsytems.
+
+use crate::bindings::{
+    spdm_state,
+    EPROTONOSUPPORT, //
+};
+use core::ffi::{
+    c_int,
+    c_void, //
+};
+use core::ptr;
+use kernel::prelude::*;
+use kernel::{
+    alloc::flags,
+    bindings, //
+};
+
+use crate::state::SpdmState;
+
+const __LOG_PREFIX: &[u8] = b"spdm\0";
+
+mod consts;
+mod state;
+mod validator;
+
+/// spdm_create() - Allocate SPDM session
+///
+/// `dev`: Responder device
+/// `transport`: Transport function to perform one message exchange
+/// `transport_priv`: Transport private data
+/// `transport_sz`: Maximum message size the transport is capable of (in bytes)
+/// `validate`: Function to validate additional leaf certificate requirements
+///  (optional, may be %NULL)
+///
+/// Return a pointer to the allocated SPDM session state or NULL on error.
+#[export]
+pub extern "C" fn spdm_create(
+    dev: *mut bindings::device,
+    transport: bindings::spdm_transport,
+    transport_priv: *mut c_void,
+    transport_sz: u32,
+    validate: bindings::spdm_validate,
+) -> *mut spdm_state {
+    match KBox::new(
+        SpdmState::new(dev, transport, transport_priv, transport_sz, validate),
+        flags::GFP_KERNEL,
+    ) {
+        Ok(ret) => KBox::into_raw(ret) as *mut spdm_state,
+        Err(_) => ptr::null_mut(),
+    }
+}
+
+/// spdm_authenticate() - Authenticate device
+///
+/// @spdm_state: SPDM session state
+///
+/// Authenticate a device through a sequence of GET_VERSION, GET_CAPABILITIES,
+/// NEGOTIATE_ALGORITHMS, GET_DIGESTS, GET_CERTIFICATE and CHALLENGE exchanges.
+///
+/// Return 0 on success or a negative errno.  In particular, -EPROTONOSUPPORT
+/// indicates authentication is not supported by the device.
+#[export]
+pub extern "C" fn spdm_authenticate(_state_ptr: *mut spdm_state) -> c_int {
+    -(EPROTONOSUPPORT as i32)
+}
+
+/// spdm_destroy() - Destroy SPDM session
+///
+/// @spdm_state: SPDM session state
+#[export]
+pub extern "C" fn spdm_destroy(state_ptr: *mut spdm_state) {
+    if state_ptr.is_null() {
+        return;
+    }
+    // SAFETY: `state_ptr` was returned from `spdm_create` (which uses
+    // `KBox::into_raw`) and the caller guarantees the state is no longer
+    // in use.  Reconstructing the `KBox` and dropping it frees the state.
+    drop(unsafe { KBox::from_raw(state_ptr as *mut SpdmState) });
+}
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
new file mode 100644
index 000000000000..e1f74d19ac4b
--- /dev/null
+++ b/lib/rspdm/state.rs
@@ -0,0 +1,237 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 Western Digital
+
+//! The `SpdmState` struct and implementation.
+//!
+//! Rust implementation of the DMTF Security Protocol and Data Model (SPDM)
+//! <https://www.dmtf.org/dsp/DSP0274>
+
+use core::ffi::c_void;
+use kernel::prelude::*;
+use kernel::{
+    bindings,
+    error::{
+        code::EINVAL,
+        to_result,
+        Error, //
+    },
+    validate::Untrusted,
+};
+
+use crate::consts::{
+    SpdmErrorCode,
+    SPDM_ERROR,
+    SPDM_MIN_VER,
+    SPDM_REQ, //
+};
+use crate::validator::{
+    SpdmErrorRsp,
+    SpdmHeader, //
+};
+
+/// The current SPDM session state for a device. Based on the
+/// C `struct spdm_state`.
+///
+/// `dev`: Responder device.  Used for error reporting and passed to @transport.
+/// `transport`: Transport function to perform one message exchange.
+/// `transport_priv`: Transport private data.
+/// `transport_sz`: Maximum message size the transport is capable of (in bytes).
+///  Used as DataTransferSize in GET_CAPABILITIES exchange.
+/// `validate`: Function to validate additional leaf certificate requirements.
+///
+/// `version`: Maximum common supported version of requester and responder.
+///  Negotiated during GET_VERSION exchange.
+#[expect(dead_code)]
+pub(crate) struct SpdmState {
+    pub(crate) dev: *mut bindings::device,
+    pub(crate) transport: bindings::spdm_transport,
+    pub(crate) transport_priv: *mut c_void,
+    pub(crate) transport_sz: u32,
+    pub(crate) validate: bindings::spdm_validate,
+
+    // Negotiated state
+    pub(crate) version: u8,
+}
+
+impl SpdmState {
+    pub(crate) fn new(
+        dev: *mut bindings::device,
+        transport: bindings::spdm_transport,
+        transport_priv: *mut c_void,
+        transport_sz: u32,
+        validate: bindings::spdm_validate,
+    ) -> Self {
+        SpdmState {
+            dev,
+            transport,
+            transport_priv,
+            transport_sz,
+            validate,
+            version: SPDM_MIN_VER,
+        }
+    }
+
+    #[allow(dead_code)]
+    fn spdm_err(&self, rsp: &SpdmErrorRsp) -> Result<(), Error> {
+        match rsp.error_code {
+            SpdmErrorCode::InvalidRequest => {
+                pr_err!("Invalid request\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::InvalidSession => {
+                if rsp.version == 0x11 {
+                    pr_err!("Invalid session {:#x}\n", rsp.error_data);
+                    Err(EINVAL)
+                } else {
+                    pr_err!("Undefined error {:#x}\n", rsp.error_code);
+                    Err(EINVAL)
+                }
+            }
+            SpdmErrorCode::Busy => {
+                pr_err!("Busy\n");
+                Err(EBUSY)
+            }
+            SpdmErrorCode::UnexpectedRequest => {
+                pr_err!("Unexpected request\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::Unspecified => {
+                pr_err!("Unspecified error\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::DecryptError => {
+                pr_err!("Decrypt error\n");
+                Err(EIO)
+            }
+            SpdmErrorCode::UnsupportedRequest => {
+                pr_err!("Unsupported request {:#x}\n", rsp.error_data);
+                Err(EINVAL)
+            }
+            SpdmErrorCode::RequestInFlight => {
+                pr_err!("Request in flight\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::InvalidResponseCode => {
+                pr_err!("Invalid response code\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::SessionLimitExceeded => {
+                pr_err!("Session limit exceeded\n");
+                Err(EBUSY)
+            }
+            SpdmErrorCode::SessionRequired => {
+                pr_err!("Session required\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::ResetRequired => {
+                pr_err!("Reset required\n");
+                Err(ECONNRESET)
+            }
+            SpdmErrorCode::ResponseTooLarge => {
+                pr_err!("Response too large\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::RequestTooLarge => {
+                pr_err!("Request too large\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::LargeResponse => {
+                pr_err!("Large response\n");
+                Err(EMSGSIZE)
+            }
+            SpdmErrorCode::MessageLost => {
+                pr_err!("Message lost\n");
+                Err(EIO)
+            }
+            SpdmErrorCode::InvalidPolicy => {
+                pr_err!("Invalid policy\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::VersionMismatch => {
+                pr_err!("Version mismatch\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::ResponseNotReady => {
+                pr_err!("Response not ready\n");
+                Err(EINPROGRESS)
+            }
+            SpdmErrorCode::RequestResynch => {
+                pr_err!("Request resynchronization\n");
+                Err(ECONNRESET)
+            }
+            SpdmErrorCode::OperationFailed => {
+                pr_err!("Operation failed\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::NoPendingRequests => Err(ENOENT),
+            SpdmErrorCode::VendorDefinedError => {
+                pr_err!("Vendor defined error\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::RequestSessionTerminated => {
+                pr_err!("Request session terminated\n");
+                Err(EINVAL)
+            }
+            SpdmErrorCode::InvalidState => {
+                pr_err!("Invalid State\n");
+                Err(EINVAL)
+            }
+        }
+    }
+
+    /// Start a SPDM exchange
+    ///
+    /// The data in `request_buf` is sent to the device and the response is
+    /// stored in `response_buf`.
+    #[allow(dead_code)]
+    pub(crate) fn spdm_exchange(
+        &self,
+        request_buf: &mut [u8],
+        response_buf: &mut [u8],
+    ) -> Result<i32, Error> {
+        let header_size = core::mem::size_of::<SpdmHeader>();
+        let request: &SpdmHeader = Untrusted::new(&request_buf[..]).validate()?;
+
+        let transport_function = self.transport.ok_or(EINVAL)?;
+        // SAFETY: `transport_function` is provided by the new(), we are
+        // calling the function.
+        // We have a immutable reference to request_buf above, and pass
+        // another reference here.
+        // We don't have any references to the mutable response_buf
+        let length = unsafe {
+            transport_function(
+                self.transport_priv,
+                self.dev,
+                request_buf.as_ptr() as *const c_void,
+                request_buf.len(),
+                response_buf.as_mut_ptr() as *mut c_void,
+                response_buf.len(),
+            ) as i32
+        };
+        to_result(length)?;
+
+        if (length as usize) < header_size {
+            return Ok(length); // Truncated response is handled by callers
+        }
+
+        let response: &SpdmHeader = Untrusted::new(&response_buf[..]).validate()?;
+
+        if response.code == SPDM_ERROR {
+            let error_rsp: &SpdmErrorRsp =
+                Untrusted::new(&response_buf[..header_size as usize]).validate()?;
+            self.spdm_err(error_rsp)?;
+        }
+
+        if response.code != request.code & !SPDM_REQ {
+            pr_err!(
+                "Response code {:#x} does not match request code {:#x}\n",
+                response.code,
+                request.code
+            );
+            return Err(EPROTO);
+        }
+
+        Ok(length)
+    }
+}
diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
new file mode 100644
index 000000000000..323242e84580
--- /dev/null
+++ b/lib/rspdm/validator.rs
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 Western Digital
+
+//! Related structs and their Validate implementations.
+//!
+//! Rust implementation of the DMTF Security Protocol and Data Model (SPDM)
+//! <https://www.dmtf.org/dsp/DSP0274>
+
+use crate::consts::SpdmErrorCode;
+use core::mem;
+use kernel::prelude::*;
+use kernel::{
+    error::{
+        code::EINVAL,
+        Error, //
+    },
+    validate::{
+        Untrusted,
+        Validate, //
+    },
+};
+
+#[repr(C, packed)]
+pub(crate) struct SpdmHeader {
+    pub(crate) version: u8,
+    pub(crate) code: u8, /* RequestResponseCode */
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+}
+
+impl Validate<Untrusted<&[u8]>> for &SpdmHeader {
+    type Err = Error;
+
+    fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
+        if unvalidated.len() < mem::size_of::<SpdmHeader>() {
+            return Err(EINVAL);
+        }
+
+        let ptr = unvalidated.as_ptr();
+        // CAST: `SpdmHeader` only contains integers and has `repr(C)`.
+        let ptr = ptr.cast::<SpdmHeader>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        Ok(unsafe { &*ptr })
+    }
+}
+
+impl Validate<Untrusted<&mut [u8]>> for &mut SpdmHeader {
+    type Err = Error;
+
+    fn validate(unvalidated: &mut [u8]) -> Result<Self, Self::Err> {
+        if unvalidated.len() < mem::size_of::<SpdmHeader>() {
+            return Err(EINVAL);
+        }
+
+        let ptr = unvalidated.as_mut_ptr();
+        // CAST: `SpdmHeader` only contains integers and has `repr(C, packed)`.
+        let ptr = ptr.cast::<SpdmHeader>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        Ok(unsafe { &mut *ptr })
+    }
+}
+
+#[repr(C, packed)]
+pub(crate) struct SpdmErrorRsp {
+    pub(crate) version: u8,
+    /// This will always be SPDM_ERROR (0x7F)
+    pub(crate) code: u8,
+    pub(crate) error_code: SpdmErrorCode,
+    pub(crate) error_data: u8,
+}
+
+impl<'a> Validate<Untrusted<&'a [u8]>> for &'a SpdmErrorRsp {
+    type Err = Error;
+
+    fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
+        if unvalidated.len() < mem::size_of::<SpdmErrorRsp>() {
+            return Err(EINVAL);
+        }
+
+        // Reject responses whose `error_code` byte is not a known
+        // `SpdmErrorCode` discriminant before exposing the struct to callers.
+        SpdmErrorCode::try_from(unvalidated[mem::offset_of!(SpdmErrorRsp, error_code)])?;
+
+        let ptr = unvalidated.as_ptr();
+        // CAST: `SpdmErrorRsp` only contains `u8` fields and `SpdmErrorCode` which
+        // we have already checked and has `repr(C, packed)`.
+        let ptr = ptr.cast::<SpdmErrorRsp>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        Ok(unsafe { &*ptr })
+    }
+}
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index fd223b6c5aaf..d2781c27794b 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -89,6 +89,7 @@
 #include <linux/security.h>
 #include <linux/serdev.h>
 #include <linux/slab.h>
+#include <linux/spdm.h>
 #include <linux/sys_soc.h>
 #include <linux/task_work.h>
 #include <linux/tracepoint.h>
-- 
2.55.0

[PATCH v3 10/21] PCI/TSM: Rename pf0 to host

[alistair23]

From: Alistair Francis <alistair.francis@wdc.com>

Rename pci_tsm_pf0 to pci_tsm_host (and rename variables and function
names from pf0 to host) as part of converting pci_tsm_host
to be any device that knows how to speak any of CMA, IDE, or
TDISP.

This commit just renames the functions and provides no functional
change. That will happen in the next commit.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 drivers/crypto/ccp/sev-dev-tio.h |  4 +-
 drivers/crypto/ccp/sev-dev-tsm.c | 12 ++---
 drivers/pci/tsm.c                | 84 ++++++++++++++++----------------
 include/linux/pci-tsm.h          | 18 ++++---
 4 files changed, 61 insertions(+), 57 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev-tio.h b/drivers/crypto/ccp/sev-dev-tio.h
index 67512b3dbc53..78d598686487 100644
--- a/drivers/crypto/ccp/sev-dev-tio.h
+++ b/drivers/crypto/ccp/sev-dev-tio.h
@@ -53,9 +53,9 @@ struct tsm_dsm_tio {
 	struct pci_ide *ide[TIO_IDE_MAX_TC];
 };
 
-/* Describes TSM structure for PF0 pointed by pci_dev->tsm */
+/* Describes TSM structure for the link host pointed by pci_dev->tsm */
 struct tio_dsm {
-	struct pci_tsm_pf0 tsm;
+	struct pci_tsm_host tsm;
 	struct tsm_dsm_tio data;
 	struct sev_device *sev;
 };
diff --git a/drivers/crypto/ccp/sev-dev-tsm.c b/drivers/crypto/ccp/sev-dev-tsm.c
index 46f2539d2d5a..a900fd22eac9 100644
--- a/drivers/crypto/ccp/sev-dev-tsm.c
+++ b/drivers/crypto/ccp/sev-dev-tsm.c
@@ -205,7 +205,7 @@ static int stream_alloc(struct pci_dev *pdev, struct pci_ide **ide,
 	return 0;
 }
 
-static struct pci_tsm *tio_pf0_probe(struct pci_dev *pdev, struct sev_device *sev)
+static struct pci_tsm *tio_host_probe(struct pci_dev *pdev, struct sev_device *sev)
 {
 	struct tio_dsm *dsm __free(kfree) = kzalloc_obj(*dsm);
 	int rc;
@@ -213,7 +213,7 @@ static struct pci_tsm *tio_pf0_probe(struct pci_dev *pdev, struct sev_device *se
 	if (!dsm)
 		return NULL;
 
-	rc = pci_tsm_pf0_constructor(pdev, &dsm->tsm, sev->tsmdev);
+	rc = pci_tsm_host_constructor(pdev, &dsm->tsm, sev->tsmdev);
 	if (rc)
 		return NULL;
 
@@ -226,8 +226,8 @@ static struct pci_tsm *dsm_probe(struct tsm_dev *tsmdev, struct pci_dev *pdev)
 {
 	struct sev_device *sev = tsm_dev_to_sev(tsmdev);
 
-	if (is_pci_tsm_pf0(pdev))
-		return tio_pf0_probe(pdev, sev);
+	if (is_pci_tsm_host(pdev))
+		return tio_host_probe(pdev, sev);
 	return NULL;
 }
 
@@ -237,10 +237,10 @@ static void dsm_remove(struct pci_tsm *tsm)
 
 	pci_dbg(pdev, "TSM disabled\n");
 
-	if (is_pci_tsm_pf0(pdev)) {
+	if (is_pci_tsm_host(pdev)) {
 		struct tio_dsm *dsm = container_of(tsm, struct tio_dsm, tsm.base_tsm);
 
-		pci_tsm_pf0_destructor(&dsm->tsm);
+		pci_tsm_host_destructor(&dsm->tsm);
 		kfree(dsm);
 	}
 }
diff --git a/drivers/pci/tsm.c b/drivers/pci/tsm.c
index 5fdcd7f2e820..10c9c6696624 100644
--- a/drivers/pci/tsm.c
+++ b/drivers/pci/tsm.c
@@ -45,22 +45,22 @@ static inline bool has_tee(struct pci_dev *pdev)
 	return pdev->devcap & PCI_EXP_DEVCAP_TEE;
 }
 
-/* 'struct pci_tsm_pf0' wraps 'struct pci_tsm' when ->dsm_dev == ->pdev (self) */
-static struct pci_tsm_pf0 *to_pci_tsm_pf0(struct pci_tsm *tsm)
+/* 'struct pci_tsm_host' wraps 'struct pci_tsm' when ->dsm_dev == ->pdev (self) */
+static struct pci_tsm_host *to_pci_tsm_host(struct pci_tsm *tsm)
 {
 	/*
 	 * All "link" TSM contexts reference the device that hosts the DSM
 	 * interface for a set of devices. Walk to the DSM device and cast its
-	 * ->tsm context to a 'struct pci_tsm_pf0 *'.
+	 * ->tsm context to a 'struct pci_tsm_host *'.
 	 */
-	struct pci_dev *pf0 = tsm->dsm_dev;
+	struct pci_dev *host = tsm->dsm_dev;
 
-	if (!is_pci_tsm_pf0(pf0) || !is_dsm(pf0)) {
+	if (!is_pci_tsm_host(host) || !is_dsm(host)) {
 		pci_WARN_ONCE(tsm->pdev, 1, "invalid context object\n");
 		return NULL;
 	}
 
-	return container_of(pf0->tsm, struct pci_tsm_pf0, base_tsm);
+	return container_of(host->tsm, struct pci_tsm_host, base_tsm);
 }
 
 static void tsm_remove(struct pci_tsm *tsm)
@@ -186,7 +186,7 @@ static int probe_fn(struct pci_dev *pdev, void *dsm)
 static int pci_tsm_connect(struct pci_dev *pdev, struct tsm_dev *tsm_dev)
 {
 	int rc;
-	struct pci_tsm_pf0 *tsm_pf0;
+	struct pci_tsm_host *tsm_host;
 	const struct pci_tsm_ops *ops = tsm_dev->pci_ops;
 	struct pci_tsm *pci_tsm __free(tsm_remove) = ops->probe(tsm_dev, pdev);
 
@@ -197,10 +197,10 @@ static int pci_tsm_connect(struct pci_dev *pdev, struct tsm_dev *tsm_dev)
 		return -ENXIO;
 
 	pdev->tsm = pci_tsm;
-	tsm_pf0 = to_pci_tsm_pf0(pdev->tsm);
+	tsm_host = to_pci_tsm_host(pdev->tsm);
 
 	/* mutex_intr assumes connect() is always sysfs/user driven */
-	ACQUIRE(mutex_intr, lock)(&tsm_pf0->lock);
+	ACQUIRE(mutex_intr, lock)(&tsm_host->lock);
 	if ((rc = ACQUIRE_ERR(mutex_intr, &lock)))
 		return rc;
 
@@ -300,15 +300,15 @@ static int remove_fn(struct pci_dev *pdev, void *data)
 static int __pci_tsm_unbind(struct pci_dev *pdev, void *data)
 {
 	struct pci_tdi *tdi;
-	struct pci_tsm_pf0 *tsm_pf0;
+	struct pci_tsm_host *tsm_host;
 
 	lockdep_assert_held(&pci_tsm_rwsem);
 
 	if (!pdev->tsm)
 		return 0;
 
-	tsm_pf0 = to_pci_tsm_pf0(pdev->tsm);
-	guard(mutex)(&tsm_pf0->lock);
+	tsm_host = to_pci_tsm_host(pdev->tsm);
+	guard(mutex)(&tsm_host->lock);
 
 	tdi = pdev->tsm->tdi;
 	if (!tdi)
@@ -341,7 +341,7 @@ EXPORT_SYMBOL_GPL(pci_tsm_unbind);
  */
 int pci_tsm_bind(struct pci_dev *pdev, struct kvm *kvm, u32 tdi_id)
 {
-	struct pci_tsm_pf0 *tsm_pf0;
+	struct pci_tsm_host *tsm_host;
 	struct pci_tdi *tdi;
 
 	if (!kvm)
@@ -355,8 +355,8 @@ int pci_tsm_bind(struct pci_dev *pdev, struct kvm *kvm, u32 tdi_id)
 	if (!is_link_tsm(pdev->tsm->tsm_dev))
 		return -ENXIO;
 
-	tsm_pf0 = to_pci_tsm_pf0(pdev->tsm);
-	guard(mutex)(&tsm_pf0->lock);
+	tsm_host = to_pci_tsm_host(pdev->tsm);
+	guard(mutex)(&tsm_host->lock);
 
 	/* Resolve races to bind a TDI */
 	if (pdev->tsm->tdi) {
@@ -404,7 +404,7 @@ ssize_t pci_tsm_guest_req(struct pci_dev *pdev, enum pci_tsm_req_scope scope,
 			  sockptr_t req_in, size_t in_len, sockptr_t req_out,
 			  size_t out_len, u64 *tsm_code)
 {
-	struct pci_tsm_pf0 *tsm_pf0;
+	struct pci_tsm_host *tsm_host;
 	struct pci_tdi *tdi;
 	int rc;
 
@@ -422,8 +422,8 @@ ssize_t pci_tsm_guest_req(struct pci_dev *pdev, enum pci_tsm_req_scope scope,
 	if (!is_link_tsm(pdev->tsm->tsm_dev))
 		return -ENXIO;
 
-	tsm_pf0 = to_pci_tsm_pf0(pdev->tsm);
-	ACQUIRE(mutex_intr, ops_lock)(&tsm_pf0->lock);
+	tsm_host = to_pci_tsm_host(pdev->tsm);
+	ACQUIRE(mutex_intr, ops_lock)(&tsm_host->lock);
 	if ((rc = ACQUIRE_ERR(mutex_intr, &ops_lock)))
 		return rc;
 
@@ -443,7 +443,7 @@ static void pci_tsm_unbind_all(struct pci_dev *pdev)
 
 static void __pci_tsm_disconnect(struct pci_dev *pdev)
 {
-	struct pci_tsm_pf0 *tsm_pf0 = to_pci_tsm_pf0(pdev->tsm);
+	struct pci_tsm_host *tsm_host = to_pci_tsm_host(pdev->tsm);
 	const struct pci_tsm_ops *ops = to_pci_tsm_ops(pdev->tsm);
 
 	/* disconnect() mutually exclusive with subfunction pci_tsm_init() */
@@ -455,7 +455,7 @@ static void __pci_tsm_disconnect(struct pci_dev *pdev)
 	 * disconnect() is uninterruptible as it may be called for device
 	 * teardown
 	 */
-	guard(mutex)(&tsm_pf0->lock);
+	guard(mutex)(&tsm_host->lock);
 	pci_tsm_walk_fns_reverse(pdev, remove_fn, NULL);
 	ops->disconnect(pdev);
 }
@@ -494,7 +494,7 @@ static ssize_t bound_show(struct device *dev,
 			  struct device_attribute *attr, char *buf)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
-	struct pci_tsm_pf0 *tsm_pf0;
+	struct pci_tsm_host *tsm_host;
 	struct pci_tsm *tsm;
 	int rc;
 
@@ -505,9 +505,9 @@ static ssize_t bound_show(struct device *dev,
 	tsm = pdev->tsm;
 	if (!tsm)
 		return sysfs_emit(buf, "\n");
-	tsm_pf0 = to_pci_tsm_pf0(tsm);
+	tsm_host = to_pci_tsm_host(tsm);
 
-	ACQUIRE(mutex_intr, ops_lock)(&tsm_pf0->lock);
+	ACQUIRE(mutex_intr, ops_lock)(&tsm_host->lock);
 	if ((rc = ACQUIRE_ERR(mutex_intr, &ops_lock)))
 		return rc;
 
@@ -547,7 +547,7 @@ static bool pci_tsm_link_group_visible(struct kobject *kobj)
 	if (!pci_is_pcie(pdev))
 		return false;
 
-	if (is_pci_tsm_pf0(pdev))
+	if (is_pci_tsm_host(pdev))
 		return true;
 
 	/*
@@ -572,14 +572,14 @@ static umode_t pci_tsm_attr_visible(struct kobject *kobj,
 		struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
 
 		if (attr == &dev_attr_bound.attr) {
-			if (is_pci_tsm_pf0(pdev) && has_tee(pdev))
+			if (is_pci_tsm_host(pdev) && has_tee(pdev))
 				return attr->mode;
 			if (pdev->tsm && has_tee(pdev->tsm->dsm_dev))
 				return attr->mode;
 		}
 
 		if (attr == &dev_attr_dsm.attr) {
-			if (is_pci_tsm_pf0(pdev))
+			if (is_pci_tsm_host(pdev))
 				return attr->mode;
 			if (pdev->tsm && has_tee(pdev->tsm->dsm_dev))
 				return attr->mode;
@@ -587,7 +587,7 @@ static umode_t pci_tsm_attr_visible(struct kobject *kobj,
 
 		if (attr == &dev_attr_connect.attr ||
 		    attr == &dev_attr_disconnect.attr) {
-			if (is_pci_tsm_pf0(pdev))
+			if (is_pci_tsm_host(pdev))
 				return attr->mode;
 		}
 	}
@@ -662,7 +662,7 @@ static struct pci_dev *find_dsm_dev(struct pci_dev *pdev)
 	struct device *grandparent;
 	struct pci_dev *uport;
 
-	if (is_pci_tsm_pf0(pdev))
+	if (is_pci_tsm_host(pdev))
 		return pdev;
 
 	struct pci_dev *pf0 __free(pci_dev_put) = pf0_dev_get(pdev);
@@ -735,13 +735,13 @@ int pci_tsm_link_constructor(struct pci_dev *pdev, struct pci_tsm *tsm,
 EXPORT_SYMBOL_GPL(pci_tsm_link_constructor);
 
 /**
- * pci_tsm_pf0_constructor() - common 'struct pci_tsm_pf0' (DSM) initialization
- * @pdev: Physical Function 0 PCI device (as indicated by is_pci_tsm_pf0())
+ * pci_tsm_host_constructor() - common 'struct pci_tsm_host' (DSM) initialization
+ * @pdev: TSM host PCI device (as indicated by is_pci_tsm_host())
  * @tsm: context to initialize
  * @tsm_dev: Platform TEE Security Manager, initiator of security operations
  */
-int pci_tsm_pf0_constructor(struct pci_dev *pdev, struct pci_tsm_pf0 *tsm,
-			    struct tsm_dev *tsm_dev)
+int pci_tsm_host_constructor(struct pci_dev *pdev, struct pci_tsm_host *tsm,
+			     struct tsm_dev *tsm_dev)
 {
 	mutex_init(&tsm->lock);
 	tsm->doe_mb = pci_find_doe_mailbox(pdev, PCI_VENDOR_ID_PCI_SIG,
@@ -753,13 +753,13 @@ int pci_tsm_pf0_constructor(struct pci_dev *pdev, struct pci_tsm_pf0 *tsm,
 
 	return pci_tsm_link_constructor(pdev, &tsm->base_tsm, tsm_dev);
 }
-EXPORT_SYMBOL_GPL(pci_tsm_pf0_constructor);
+EXPORT_SYMBOL_GPL(pci_tsm_host_constructor);
 
-void pci_tsm_pf0_destructor(struct pci_tsm_pf0 *pf0_tsm)
+void pci_tsm_host_destructor(struct pci_tsm_host *host_tsm)
 {
-	mutex_destroy(&pf0_tsm->lock);
+	mutex_destroy(&host_tsm->lock);
 }
-EXPORT_SYMBOL_GPL(pci_tsm_pf0_destructor);
+EXPORT_SYMBOL_GPL(pci_tsm_host_destructor);
 
 int pci_tsm_register(struct tsm_dev *tsm_dev)
 {
@@ -780,7 +780,7 @@ int pci_tsm_register(struct tsm_dev *tsm_dev)
 	/* On first enable, update sysfs groups */
 	if (is_link_tsm(tsm_dev) && pci_tsm_link_count++ == 0) {
 		for_each_pci_dev(pdev)
-			if (is_pci_tsm_pf0(pdev))
+			if (is_pci_tsm_host(pdev))
 				link_sysfs_enable(pdev);
 	} else if (is_devsec_tsm(tsm_dev)) {
 		pci_tsm_devsec_count++;
@@ -815,7 +815,7 @@ static void __pci_tsm_destroy(struct pci_dev *pdev, struct tsm_dev *tsm_dev)
 	 * skipped if the device itself is being removed since sysfs goes away
 	 * naturally at that point
 	 */
-	if (is_link_tsm(tsm_dev) && is_pci_tsm_pf0(pdev) && !pci_tsm_link_count)
+	if (is_link_tsm(tsm_dev) && is_pci_tsm_host(pdev) && !pci_tsm_link_count)
 		link_sysfs_disable(pdev);
 
 	/* Nothing else to do if this device never attached to the departing TSM */
@@ -828,7 +828,7 @@ static void __pci_tsm_destroy(struct pci_dev *pdev, struct tsm_dev *tsm_dev)
 	else if (tsm_dev != tsm->tsm_dev)
 		return;
 
-	if (is_link_tsm(tsm_dev) && is_pci_tsm_pf0(pdev))
+	if (is_link_tsm(tsm_dev) && is_pci_tsm_host(pdev))
 		pci_tsm_disconnect(pdev);
 	else
 		pci_tsm_fn_exit(pdev);
@@ -885,12 +885,12 @@ void pci_tsm_unregister(struct tsm_dev *tsm_dev)
 int pci_tsm_doe_transfer(struct pci_dev *pdev, u8 type, const void *req,
 			 size_t req_sz, void *resp, size_t resp_sz)
 {
-	struct pci_tsm_pf0 *tsm;
+	struct pci_tsm_host *tsm;
 
-	if (!pdev->tsm || !is_pci_tsm_pf0(pdev))
+	if (!pdev->tsm || !is_pci_tsm_host(pdev))
 		return -ENXIO;
 
-	tsm = to_pci_tsm_pf0(pdev->tsm);
+	tsm = to_pci_tsm_host(pdev->tsm);
 	if (!tsm->doe_mb)
 		return -ENXIO;
 
diff --git a/include/linux/pci-tsm.h b/include/linux/pci-tsm.h
index a6435aba03f9..950e2c36a4ca 100644
--- a/include/linux/pci-tsm.h
+++ b/include/linux/pci-tsm.h
@@ -40,7 +40,7 @@ struct pci_tsm_ops {
 	 * pci_tsm_rwsem held for write to sync with TSM unregistration and
 	 * mutual exclusion of @connect and @disconnect. @connect and
 	 * @disconnect additionally run under the DSM lock (struct
-	 * pci_tsm_pf0::lock) as well as @probe and @remove of the subfunctions.
+	 * pci_tsm_host::lock) as well as @probe and @remove of the subfunctions.
 	 * @bind, @unbind, and @guest_req run under pci_tsm_rwsem held for read
 	 * and the DSM lock.
 	 */
@@ -115,19 +115,23 @@ struct pci_tsm {
 };
 
 /**
- * struct pci_tsm_pf0 - Physical Function 0 TDISP link context
+ * struct pci_tsm_host - TSM host link context (CMA, IDE, or TDISP)
  * @base_tsm: generic core "tsm" context
  * @lock: mutual exclustion for pci_tsm_ops invocation
  * @doe_mb: PCIe Data Object Exchange mailbox
+ *
+ * The host of a TSM link is the device that knows how to speak
+ * CMA, IDE, or TDISP. For TDISP / IDE that is a Physical Function 0.
+ * For CMA-only it is a CMA DOE mailbox.
  */
-struct pci_tsm_pf0 {
+struct pci_tsm_host {
 	struct pci_tsm base_tsm;
 	struct mutex lock;
 	struct pci_doe_mb *doe_mb;
 };
 
 /* physical function0 and capable of 'connect' */
-static inline bool is_pci_tsm_pf0(struct pci_dev *pdev)
+static inline bool is_pci_tsm_host(struct pci_dev *pdev)
 {
 	if (!pdev)
 		return false;
@@ -204,9 +208,9 @@ int pci_tsm_register(struct tsm_dev *tsm_dev);
 void pci_tsm_unregister(struct tsm_dev *tsm_dev);
 int pci_tsm_link_constructor(struct pci_dev *pdev, struct pci_tsm *tsm,
 			     struct tsm_dev *tsm_dev);
-int pci_tsm_pf0_constructor(struct pci_dev *pdev, struct pci_tsm_pf0 *tsm,
-			    struct tsm_dev *tsm_dev);
-void pci_tsm_pf0_destructor(struct pci_tsm_pf0 *tsm);
+int pci_tsm_host_constructor(struct pci_dev *pdev, struct pci_tsm_host *tsm,
+			     struct tsm_dev *tsm_dev);
+void pci_tsm_host_destructor(struct pci_tsm_host *tsm);
 int pci_tsm_doe_transfer(struct pci_dev *pdev, u8 type, const void *req,
 			 size_t req_sz, void *resp, size_t resp_sz);
 int pci_tsm_bind(struct pci_dev *pdev, struct kvm *kvm, u32 tdi_id);
-- 
2.55.0

[PATCH v3 11/21] PCI/TSM: Support connecting to PCIe CMA devices

[alistair23]

From: Alistair Francis <alistair.francis@wdc.com>

In the next patch we are going to add a PCIe CMA TSM driver, as such we
need to ensure that is_pci_tsm_host() will allow us to connect to CMA
capable devices. These devices don't necessarily has DEVCAP_TEE or IDE
support.

To avoid calling pci_find_doe_mailbox() everytime is_pci_tsm_host() is
called we can cache the CMA support in struct pci_dev and just check
against that.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 drivers/pci/doe.c       |  3 +++
 drivers/pci/tsm.c       | 31 +++++++++++++++++++++++++------
 include/linux/pci-tsm.h | 12 +++++++++++-
 include/linux/pci.h     |  1 +
 4 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
index ac95b1d2d999..6a59969bd52f 100644
--- a/drivers/pci/doe.c
+++ b/drivers/pci/doe.c
@@ -870,6 +870,9 @@ void pci_doe_init(struct pci_dev *pdev)
 			pci_doe_destroy_mb(doe_mb);
 		}
 	}
+
+	pdev->doe_cma = pci_find_doe_mailbox(pdev, PCI_VENDOR_ID_PCI_SIG,
+					     PCI_DOE_FEATURE_CMA);
 }
 
 void pci_doe_destroy(struct pci_dev *pdev)
diff --git a/drivers/pci/tsm.c b/drivers/pci/tsm.c
index 10c9c6696624..440f818ac569 100644
--- a/drivers/pci/tsm.c
+++ b/drivers/pci/tsm.c
@@ -88,8 +88,8 @@ static void pci_tsm_walk_fns(struct pci_dev *pdev,
 		if (!pf)
 			continue;
 
-		/* on entry function 0 has already run @cb */
-		if (i > 0)
+		/* the caller is responsible for running @cb on the host itself */
+		if (pf != pdev)
 			cb(pf, data);
 
 		/* walk virtual functions of each pf */
@@ -145,8 +145,8 @@ static void pci_tsm_walk_fns_reverse(struct pci_dev *pdev,
 			cb(vf, data);
 		}
 
-		/* on exit, caller will run @cb on function 0 */
-		if (i > 0)
+		/* the caller is responsible for running @cb on the host itself */
+		if (pf != pdev)
 			cb(pf, data);
 	}
 }
@@ -287,6 +287,16 @@ static DEVICE_ATTR_RW(connect);
 
 static int remove_fn(struct pci_dev *pdev, void *data)
 {
+	struct pci_dev *host = data;
+
+	/*
+	 * Only teardown the security context of functions that belong to the
+	 * DSM being disconnected, leaving any sibling DSM in the same slot
+	 * untouched.
+	 */
+	if (!pdev->tsm || pdev->tsm->dsm_dev != host)
+		return 0;
+
 	tsm_remove(pdev->tsm);
 	link_sysfs_disable(pdev);
 	return 0;
@@ -299,6 +309,7 @@ static int remove_fn(struct pci_dev *pdev, void *data)
  */
 static int __pci_tsm_unbind(struct pci_dev *pdev, void *data)
 {
+	struct pci_dev *host = data;
 	struct pci_tdi *tdi;
 	struct pci_tsm_host *tsm_host;
 
@@ -307,6 +318,14 @@ static int __pci_tsm_unbind(struct pci_dev *pdev, void *data)
 	if (!pdev->tsm)
 		return 0;
 
+	/*
+	 * When walking a DSM's dependent functions skip any that belong to a
+	 * different DSM in the same slot. A NULL @host is a direct unbind of
+	 * @pdev itself.
+	 */
+	if (host && pdev->tsm->dsm_dev != host)
+		return 0;
+
 	tsm_host = to_pci_tsm_host(pdev->tsm);
 	guard(mutex)(&tsm_host->lock);
 
@@ -437,7 +456,7 @@ EXPORT_SYMBOL_GPL(pci_tsm_guest_req);
 
 static void pci_tsm_unbind_all(struct pci_dev *pdev)
 {
-	pci_tsm_walk_fns_reverse(pdev, __pci_tsm_unbind, NULL);
+	pci_tsm_walk_fns_reverse(pdev, __pci_tsm_unbind, pdev);
 	__pci_tsm_unbind(pdev, NULL);
 }
 
@@ -456,7 +475,7 @@ static void __pci_tsm_disconnect(struct pci_dev *pdev)
 	 * teardown
 	 */
 	guard(mutex)(&tsm_host->lock);
-	pci_tsm_walk_fns_reverse(pdev, remove_fn, NULL);
+	pci_tsm_walk_fns_reverse(pdev, remove_fn, pdev);
 	ops->disconnect(pdev);
 }
 
diff --git a/include/linux/pci-tsm.h b/include/linux/pci-tsm.h
index 950e2c36a4ca..f504fa680315 100644
--- a/include/linux/pci-tsm.h
+++ b/include/linux/pci-tsm.h
@@ -3,6 +3,7 @@
 #define __PCI_TSM_H
 #include <linux/mutex.h>
 #include <linux/pci.h>
+#include <linux/pci-doe.h>
 #include <linux/sockptr.h>
 
 struct pci_tsm;
@@ -130,7 +131,7 @@ struct pci_tsm_host {
 	struct pci_doe_mb *doe_mb;
 };
 
-/* physical function0 and capable of 'connect' */
+/* device is a TSM host and capable of 'connect' */
 static inline bool is_pci_tsm_host(struct pci_dev *pdev)
 {
 	if (!pdev)
@@ -142,6 +143,15 @@ static inline bool is_pci_tsm_host(struct pci_dev *pdev)
 	if (pdev->is_virtfn)
 		return false;
 
+	/*
+	 * Report capable if CMA is supported, which can be supported on any PCIe
+	 * device.
+	 */
+#ifdef CONFIG_PCI_DOE
+	if (pdev->doe_cma)
+		return true;
+#endif
+
 	/*
 	 * Allow for a Device Security Manager (DSM) associated with function0
 	 * of an Endpoint to coordinate TDISP requests for other functions
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d31a8d107b1e..cb13b40952b4 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -565,6 +565,7 @@ struct pci_dev {
 #endif
 #ifdef CONFIG_PCI_DOE
 	struct xarray	doe_mbs;	/* Data Object Exchange mailboxes */
+	bool		doe_cma;	/* A CMA/SPDM DOE mailbox is present */
 #endif
 #ifdef CONFIG_PCI_NPEM
 	struct npem	*npem;		/* Native PCIe Enclosure Management */
-- 
2.55.0

[PATCH v3 12/21] PCI/CMA: Add a PCI TSM CMA driver using SPDM

[alistair23]

From: Alistair Francis <alistair.francis@wdc.com>

Component Measurement and Authentication (CMA, PCIe r6.2 sec 6.31)
allows for measurement and authentication of PCIe devices.  It is
based on the Security Protocol and Data Model specification (SPDM,
https://www.dmtf.org/dsp/DSP0274).

CMA-SPDM in turn forms the basis for Integrity and Data Encryption
(IDE, PCIe r6.2 sec 6.33) because the key material used by IDE is
transmitted over a CMA-SPDM session.

As a first step, add support for authentication via a CMA TSM driver.

This was previously discusd here:
http://lore.kernel.org/69976d7d39c60_2f4a1009@dwillia2-mobl4.notmuch

By utilising a TSM driver we get a lot of the TSM driver probe policies
"for free". Currently there is no mechanism to provide evidence to
userspace, as the TSM system doesn't support that at the moment. That
can be added later when support by TSM.

Credits: Jonathan wrote the original proof-of-concept for a CMA implementation.
Lukas reworked that for upstream. Wilfred contributed fixes for issues
discovered during testing. Alistair reworked it as a TSM driver.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Co-developed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Co-developed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 MAINTAINERS             |   1 +
 drivers/pci/Kconfig     |  14 ++++
 drivers/pci/Makefile    |   2 +
 drivers/pci/cma.c       | 154 ++++++++++++++++++++++++++++++++++++++++
 drivers/pci/doe.c       |   3 -
 include/linux/pci-doe.h |   4 ++
 6 files changed, 175 insertions(+), 3 deletions(-)
 create mode 100644 drivers/pci/cma.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 36f84a02894b..89cd64f88ebb 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -24762,6 +24762,7 @@ L:	linux-cxl@vger.kernel.org
 L:	linux-pci@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/devsec/spdm.git
+F:	drivers/pci/cma.c
 F:	include/linux/spdm.h
 F:	lib/rspdm/
 
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 0c7408509ba2..0862ef69aa3f 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -124,6 +124,20 @@ config PCI_ATS
 config PCI_IDE
 	bool
 
+config PCI_CMA
+	bool "Component Measurement and Authentication (CMA-SPDM)"
+	depends on RSPDM
+	select CRYPTO_ECDSA
+	select CRYPTO_RSA
+	select CRYPTO_SHA256
+	select CRYPTO_SHA512
+	select PCI_DOE
+	select PCI_TSM
+	help
+	  Authenticate devices on enumeration per PCIe r6.2 sec 6.31.
+	  A PCI DOE mailbox is used as transport for DMTF SPDM based
+	  authentication, measurement and secure channel establishment.
+
 config PCI_TSM
 	bool "PCI TSM: Device security protocol support"
 	select PCI_IDE
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 41ebc3b9a518..16abfd0e17e1 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -41,6 +41,8 @@ obj-$(CONFIG_PCI_NPEM)		+= npem.o
 obj-$(CONFIG_PCIE_TPH)		+= tph.o
 obj-$(CONFIG_CARDBUS)		+= setup-cardbus.o
 
+obj-$(CONFIG_PCI_CMA)		+= cma.o
+
 # Endpoint library must be initialized before its users
 obj-$(CONFIG_PCI_ENDPOINT)	+= endpoint/
 
diff --git a/drivers/pci/cma.c b/drivers/pci/cma.c
new file mode 100644
index 000000000000..9f2cc0b2ec8a
--- /dev/null
+++ b/drivers/pci/cma.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Component Measurement and Authentication (CMA-SPDM, PCIe r6.2 sec 6.31)
+ *
+ * Copyright (C) 2021 Huawei
+ *     Jonathan Cameron <Jonathan.Cameron@huawei.com>
+ * Copyright (C) 2022-24 Intel Corporation
+ * Copyright (C) 2026 Western Digital
+ * 	Alistair Francis <alistair.francis@wdc.com>
+ */
+
+#define dev_fmt(fmt) "CMA: " fmt
+
+#include <linux/err.h>
+#include <linux/pci.h>
+#include <linux/pci-doe.h>
+#include <linux/pci-tsm.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spdm.h>
+#include <linux/tsm.h>
+
+#include "pci.h"
+
+static int pci_doe_transport(void *priv, struct device *dev,
+			     const void *request, size_t request_sz,
+			     void *response, size_t response_sz)
+{
+	struct pci_doe_mb *doe = priv;
+
+	return pci_doe(doe, PCI_VENDOR_ID_PCI_SIG, PCI_DOE_FEATURE_CMA,
+		       request, request_sz, response, response_sz);
+}
+
+struct pci_cma_tsm {
+	struct pci_tsm_host host;
+	struct spdm_state *spdm;
+};
+
+static struct pci_cma_tsm *cma_tsm_from_tsm(struct pci_tsm *tsm)
+{
+	struct pci_tsm_host *host = container_of(tsm, struct pci_tsm_host, base_tsm);
+
+	return container_of(host, struct pci_cma_tsm, host);
+}
+
+static struct pci_tsm *pci_cma_tsm_probe(struct tsm_dev *tsm_dev,
+					 struct pci_dev *pdev)
+{
+	struct pci_cma_tsm *cma;
+	int rc;
+
+	cma = kzalloc(sizeof(*cma), GFP_KERNEL);
+	if (!cma)
+		return NULL;
+
+	rc = pci_tsm_host_constructor(pdev, &cma->host, tsm_dev);
+	if (rc) {
+		kfree(cma);
+		return NULL;
+	}
+
+	cma->spdm = spdm_create(&pdev->dev, pci_doe_transport, cma->host.doe_mb,
+				PCI_DOE_MAX_PAYLOAD, NULL);
+	if (!cma->spdm) {
+		pci_tsm_host_destructor(&cma->host);
+		kfree(cma);
+		return NULL;
+	}
+
+	return &cma->host.base_tsm;
+}
+
+static void pci_cma_tsm_remove(struct pci_tsm *tsm)
+{
+	struct pci_cma_tsm *cma = cma_tsm_from_tsm(tsm);
+
+	spdm_destroy(cma->spdm);
+	pci_tsm_host_destructor(&cma->host);
+	kfree(cma);
+}
+
+static int pci_cma_tsm_connect(struct pci_dev *pdev)
+{
+	struct pci_cma_tsm *cma = cma_tsm_from_tsm(pdev->tsm);
+	int rc;
+
+	/*
+	 * The DOE mailbox lives in the device's config space, so the
+	 * device must be runtime-resumed for the duration of the SPDM
+	 * exchange.
+	 */
+	rc = pm_runtime_get_sync(&pdev->dev);
+	if (rc < 0) {
+		pm_runtime_put_noidle(&pdev->dev);
+		return rc;
+	}
+
+	rc = spdm_authenticate(cma->spdm);
+
+	pm_runtime_put_sync(&pdev->dev);
+	return rc;
+}
+
+static void pci_cma_tsm_disconnect(struct pci_dev *pdev)
+{
+	/* SPDM state is freed in pci_cma_tsm_remove() */
+}
+
+static struct pci_tdi *pci_cma_tsm_bind(struct pci_dev *pdev,
+					struct kvm *kvm, u32 tdi_id)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+static void pci_cma_tsm_unbind(struct pci_tdi *tdi)
+{
+}
+
+static ssize_t pci_cma_tsm_guest_req(struct pci_tdi *tdi,
+				     enum pci_tsm_req_scope scope,
+				     sockptr_t req_in, size_t in_len,
+				     sockptr_t req_out, size_t out_len,
+				     u64 *tsm_code)
+{
+	return -EOPNOTSUPP;
+}
+
+static const struct pci_tsm_ops pci_cma_tsm_ops = {
+	.link_ops = {
+		.probe		= pci_cma_tsm_probe,
+		.remove		= pci_cma_tsm_remove,
+		.connect	= pci_cma_tsm_connect,
+		.disconnect	= pci_cma_tsm_disconnect,
+		.bind		= pci_cma_tsm_bind,
+		.unbind		= pci_cma_tsm_unbind,
+		.guest_req	= pci_cma_tsm_guest_req,
+	},
+};
+
+static struct tsm_dev *pci_cma_tsm_dev;
+
+static int __init pci_cma_tsm_init(void)
+{
+	struct tsm_dev *tsm_dev;
+
+	tsm_dev = tsm_register(NULL, (struct pci_tsm_ops *)&pci_cma_tsm_ops);
+	if (IS_ERR(tsm_dev))
+		return PTR_ERR(tsm_dev);
+
+	pci_cma_tsm_dev = tsm_dev;
+	return 0;
+}
+late_initcall(pci_cma_tsm_init);
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
index 6a59969bd52f..1b3d6e74fbe8 100644
--- a/drivers/pci/doe.c
+++ b/drivers/pci/doe.c
@@ -31,9 +31,6 @@
 #define PCI_DOE_FLAG_CANCEL	0
 #define PCI_DOE_FLAG_DEAD	1
 
-/* Max data object length is 2^18 dwords */
-#define PCI_DOE_MAX_LENGTH	(1 << 18)
-
 /**
  * struct pci_doe_mb - State for a single DOE mailbox
  *
diff --git a/include/linux/pci-doe.h b/include/linux/pci-doe.h
index bd4346a7c4e7..7540396336de 100644
--- a/include/linux/pci-doe.h
+++ b/include/linux/pci-doe.h
@@ -19,6 +19,10 @@ struct pci_doe_mb;
 #define PCI_DOE_FEATURE_CMA 1
 #define PCI_DOE_FEATURE_SSESSION 2
 
+/* Max data object length is 2^18 dwords (including 2 dwords for header) */
+#define PCI_DOE_MAX_LENGTH	(1 << 18)
+#define PCI_DOE_MAX_PAYLOAD	((PCI_DOE_MAX_LENGTH - 2) * sizeof(u32))
+
 struct pci_doe_mb *pci_find_doe_mailbox(struct pci_dev *pdev, u16 vendor,
 					u8 type);
 
-- 
2.55.0

[PATCH v3 13/21] PCI/CMA: Validate Subject Alternative Name in certificates

[alistair23]

From: Lukas Wunner <lukas@wunner.de>

PCIe r6.1 sec 6.31.3 stipulates requirements for Leaf Certificates
presented by devices, in particular the presence of a Subject Alternative
Name which encodes the Vendor ID, Device ID, Device Serial Number, etc.

This prevents a mismatch between the device identity in Config Space and
the certificate.  A device cannot misappropriate a certificate from a
different device without also spoofing Config Space.  As a corollary,
it cannot dupe an arbitrary driver into binding to it.  Only drivers
which bind to the device identity in the Subject Alternative Name work
(PCIe r6.1 sec 6.31 "Implementation Note: Overview of Threat Model").

The Subject Alternative Name is signed, hence constitutes a signed copy
of a Config Space portion.  It's the same concept as web certificates
which contain a set of domain names in the Subject Alternative Name for
identity verification.

Parse the Subject Alternative Name using a small ASN.1 module and
validate its contents.  The theory of operation is explained in a
comment at the top of the newly inserted code.

This functionality is introduced in a separate commit on top of basic
CMA-SPDM support to split the code into digestible, reviewable chunks.

The CMA OID added here is taken from the official OID Repository
(it's not documented in the PCIe Base Spec):
https://oid-rep.orange-labs.fr/get/2.23.147

Side notes:

* PCIe r6.2 removes the spec language on the Subject Alternative Name.
  It still "requires the leaf certificate to include the information
  typically used by system software for device driver binding", but no
  longer specifies how that information is encoded into the certificate.

  According to the editor of the PCIe Base Spec and the author of the
  CMA 1.1 ECN (which caused this change), FPGA cards which mutate their
  device identity at runtime (due to a firmware update) were thought as
  unable to satisfy the previous spec language.  The Protocol Working
  Group could not agree on a better solution and therefore dropped the
  spec language entirely.  They acknowledge that the requirement is now
  under-spec'd.  Because products already exist which adhere to the
  Subject Alternative Name requirement per PCIe r6.1 sec 6.31.3, they
  recommended to "push through" and use it as the de facto standard.

  The FPGA concerns are easily overcome by reauthenticating the device
  after a firmware update, either via sysfs or pci_cma_reauthenticate()
  (added by a subsequent commit).

* PCIe r6.1 sec 6.31.3 strongly recommends to verify that "the
  information provided in the Subject Alternative Name entry is signed
  by the vendor indicated by the Vendor ID."  In other words, the root
  certificate on pci_cma_keyring which signs the device's certificate
  chain must have been created for a particular Vendor ID.

  Unfortunately the spec neglects to define how the Vendor ID shall be
  encoded into the root certificate.  So the recommendation cannot be
  implemented at this point and it is thus possible that a vendor signs
  device certificates of a different vendor.

* Instead of a Subject Alternative Name, Leaf Certificates may include
  "a Reference Integrity Manifest, e.g., see Trusted Computing Group" or
  "a pointer to a location where such a Reference Integrity Manifest can
  be obtained" (PCIe r6.1 sec 6.31.3).

  A Reference Integrity Manifest contains "golden" measurements which
  can be compared to actual measurements retrieved from a device.
  It serves a different purpose than the Subject Alternative Name,
  hence it is unclear why the spec says only either of them is necessary.
  It is also unclear how a Reference Integrity Manifest shall be encoded
  into a certificate.

  Hence ignore the Reference Integrity Manifest requirement.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # except ASN.1
[ Changed by AF:
 - Fixup a few issues caught by Sashiko
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 drivers/pci/Makefile         |   5 +-
 drivers/pci/cma.asn1         |  41 ++++++++++++
 drivers/pci/cma.c            | 123 ++++++++++++++++++++++++++++++++++-
 include/linux/oid_registry.h |   3 +
 4 files changed, 170 insertions(+), 2 deletions(-)
 create mode 100644 drivers/pci/cma.asn1

diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 16abfd0e17e1..882cbb108364 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -41,7 +41,10 @@ obj-$(CONFIG_PCI_NPEM)		+= npem.o
 obj-$(CONFIG_PCIE_TPH)		+= tph.o
 obj-$(CONFIG_CARDBUS)		+= setup-cardbus.o
 
-obj-$(CONFIG_PCI_CMA)		+= cma.o
+obj-$(CONFIG_PCI_CMA)		+= pci-cma.o
+pci-cma-y			:= cma.o cma.asn1.o
+$(obj)/cma.o:			$(obj)/cma.asn1.h
+$(obj)/cma.asn1.o:		$(obj)/cma.asn1.c $(obj)/cma.asn1.h
 
 # Endpoint library must be initialized before its users
 obj-$(CONFIG_PCI_ENDPOINT)	+= endpoint/
diff --git a/drivers/pci/cma.asn1 b/drivers/pci/cma.asn1
new file mode 100644
index 000000000000..da41421d4085
--- /dev/null
+++ b/drivers/pci/cma.asn1
@@ -0,0 +1,41 @@
+-- SPDX-License-Identifier: BSD-3-Clause
+--
+-- Component Measurement and Authentication (CMA-SPDM, PCIe r6.1 sec 6.31.3)
+-- X.509 Subject Alternative Name (RFC 5280 sec 4.2.1.6)
+--
+-- Copyright (C) 2008 IETF Trust and the persons identified as authors
+-- of the code
+--
+-- https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.6
+--
+-- The ASN.1 module in RFC 5280 appendix A.1 uses EXPLICIT TAGS whereas the one
+-- in appendix A.2 uses IMPLICIT TAGS.  The kernel's simplified asn1_compiler.c
+-- always uses EXPLICIT TAGS, hence this ASN.1 module differs from RFC 5280 in
+-- that it adds IMPLICIT to definitions from appendix A.2 (such as GeneralName)
+-- and omits EXPLICIT in those definitions.
+
+SubjectAltName ::= GeneralNames
+
+GeneralNames ::= SEQUENCE OF GeneralName
+
+GeneralName ::= CHOICE {
+	otherName			[0] IMPLICIT OtherName,
+	rfc822Name			[1] IMPLICIT IA5String,
+	dNSName				[2] IMPLICIT IA5String,
+	x400Address			[3] ANY,
+	directoryName			[4] ANY,
+	ediPartyName			[5] IMPLICIT EDIPartyName,
+	uniformResourceIdentifier	[6] IMPLICIT IA5String,
+	iPAddress			[7] IMPLICIT OCTET STRING,
+	registeredID			[8] IMPLICIT OBJECT IDENTIFIER
+	}
+
+OtherName ::= SEQUENCE {
+	type-id			OBJECT IDENTIFIER ({ pci_cma_note_oid }),
+	value			[0] ANY ({ pci_cma_note_san })
+	}
+
+EDIPartyName ::= SEQUENCE {
+	nameAssigner		[0] ANY OPTIONAL,
+	partyName		[1] ANY
+	}
diff --git a/drivers/pci/cma.c b/drivers/pci/cma.c
index 9f2cc0b2ec8a..39a858436b28 100644
--- a/drivers/pci/cma.c
+++ b/drivers/pci/cma.c
@@ -12,6 +12,9 @@
 #define dev_fmt(fmt) "CMA: " fmt
 
 #include <linux/err.h>
+#include <keys/x509-parser.h>
+#include <linux/asn1_decoder.h>
+#include <linux/oid_registry.h>
 #include <linux/pci.h>
 #include <linux/pci-doe.h>
 #include <linux/pci-tsm.h>
@@ -20,8 +23,126 @@
 #include <linux/spdm.h>
 #include <linux/tsm.h>
 
+#include "cma.asn1.h"
 #include "pci.h"
 
+/*
+ * The spdm_requester.c library calls pci_cma_validate() to check requirements
+ * for Leaf Certificates per PCIe r6.1 sec 6.31.3.
+ *
+ * pci_cma_validate() parses the Subject Alternative Name using the ASN.1
+ * module cma.asn1, which calls pci_cma_note_oid() and pci_cma_note_san()
+ * to compare an OtherName against the expected name.
+ *
+ * The expected name is constructed beforehand by pci_cma_construct_san().
+ *
+ * PCIe r6.2 drops the Subject Alternative Name spec language, even though
+ * it continues to require "the leaf certificate to include the information
+ * typically used by system software for device driver binding".  Use the
+ * Subject Alternative Name per PCIe r6.1 for lack of a replacement and
+ * because it is the de facto standard among existing products.
+ */
+#define CMA_NAME_MAX sizeof("Vendor=1234:Device=1234:CC=123456:"	  \
+			    "REV=12:SSVID=1234:SSID=1234:1234567890123456")
+
+struct pci_cma_x509_context {
+	struct pci_dev *pdev;
+	u8 slot;
+	enum OID last_oid;
+	char expected_name[CMA_NAME_MAX];
+	unsigned int expected_len;
+	unsigned int found:1;
+};
+
+int pci_cma_note_oid(void *context, size_t hdrlen, unsigned char tag,
+		     const void *value, size_t vlen)
+{
+	struct pci_cma_x509_context *ctx = context;
+
+	ctx->last_oid = look_up_OID(value, vlen);
+
+	return 0;
+}
+
+int pci_cma_note_san(void *context, size_t hdrlen, unsigned char tag,
+		     const void *value, size_t vlen)
+{
+	struct pci_cma_x509_context *ctx = context;
+
+	/* These aren't the drOIDs we're looking for. */
+	if (ctx->last_oid != OID_CMA)
+		return 0;
+
+	if (tag != ASN1_UTF8STR ||
+	    vlen != ctx->expected_len ||
+	    memcmp(value, ctx->expected_name, vlen) != 0) {
+		pci_err(ctx->pdev, "Leaf certificate of slot %u "
+			"has invalid Subject Alternative Name\n", ctx->slot);
+		return -EINVAL;
+	}
+
+	ctx->found = true;
+
+	return 0;
+}
+
+static unsigned int pci_cma_construct_san(struct pci_dev *pdev, char *name)
+{
+	unsigned int len;
+	u64 serial;
+
+	len = scnprintf(name, CMA_NAME_MAX,
+			"Vendor=%04hx:Device=%04hx:CC=%06x:REV=%02hhx",
+			pdev->vendor, pdev->device, pdev->class, pdev->revision);
+
+	if (pdev->hdr_type == PCI_HEADER_TYPE_NORMAL)
+		len += scnprintf(name + len, CMA_NAME_MAX - len,
+				 ":SSVID=%04hx:SSID=%04hx",
+				 pdev->subsystem_vendor, pdev->subsystem_device);
+
+	serial = pci_get_dsn(pdev);
+	if (serial)
+		len += scnprintf(name + len, CMA_NAME_MAX - len,
+				 ":%016llx", serial);
+
+	return len;
+}
+
+static int pci_cma_validate(struct device *dev, u8 slot,
+			    struct x509_certificate *leaf_cert)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct pci_cma_x509_context ctx;
+	int ret;
+
+	if (!leaf_cert->raw_san) {
+		pci_err(pdev, "Leaf certificate of slot %u "
+			"has no Subject Alternative Name\n", slot);
+		return -EINVAL;
+	}
+
+	ctx.pdev = pdev;
+	ctx.slot = slot;
+	ctx.found = false;
+	ctx.expected_len = pci_cma_construct_san(pdev, ctx.expected_name);
+
+	ret = asn1_ber_decoder(&cma_decoder, &ctx, leaf_cert->raw_san,
+			       leaf_cert->raw_san_size);
+	if (ret == -EBADMSG || ret == -EMSGSIZE)
+		pci_err(pdev, "Leaf certificate of slot %u "
+			"has malformed Subject Alternative Name\n", slot);
+	if (ret < 0)
+		return ret;
+
+	if (!ctx.found) {
+		pci_err(pdev, "Leaf certificate of slot %u "
+			"has no OtherName with CMA OID\n", slot);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int pci_doe_transport(void *priv, struct device *dev,
 			     const void *request, size_t request_sz,
 			     void *response, size_t response_sz)
@@ -61,7 +182,7 @@ static struct pci_tsm *pci_cma_tsm_probe(struct tsm_dev *tsm_dev,
 	}
 
 	cma->spdm = spdm_create(&pdev->dev, pci_doe_transport, cma->host.doe_mb,
-				PCI_DOE_MAX_PAYLOAD, NULL);
+				PCI_DOE_MAX_PAYLOAD, pci_cma_validate);
 	if (!cma->spdm) {
 		pci_tsm_host_destructor(&cma->host);
 		kfree(cma);
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index ebce402854de..113f4e802ec4 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h
@@ -150,6 +150,9 @@ enum OID {
 	OID_id_ml_dsa_65,			/* 2.16.840.1.101.3.4.3.18 */
 	OID_id_ml_dsa_87,			/* 2.16.840.1.101.3.4.3.19 */
 
+	/* PCI */
+	OID_CMA,			/* 2.23.147 */
+
 	OID__NR
 };
 
-- 
2.55.0

[PATCH v3 14/21] lib: rspdm: Support SPDM get_version

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

Support the GET_VERSION SPDM command.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 lib/rspdm/consts.rs    | 16 ++++++++--
 lib/rspdm/lib.rs       | 54 +++++++++++++++++++++++++++------
 lib/rspdm/state.rs     | 67 ++++++++++++++++++++++++++++++++++++++--
 lib/rspdm/validator.rs | 69 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 192 insertions(+), 14 deletions(-)

diff --git a/lib/rspdm/consts.rs b/lib/rspdm/consts.rs
index 01f008958a1f..055671d43abd 100644
--- a/lib/rspdm/consts.rs
+++ b/lib/rspdm/consts.rs
@@ -7,16 +7,24 @@
 //! Rust implementation of the DMTF Security Protocol and Data Model (SPDM)
 //! <https://www.dmtf.org/dsp/DSP0274>
 
+use crate::validator::GetVersionRsp;
+use core::mem;
 use kernel::error::{code::EINVAL, Error};
 
 // SPDM versions supported by this implementation
 pub(crate) const SPDM_VER_10: u8 = 0x10;
+#[allow(dead_code)]
+pub(crate) const SPDM_VER_11: u8 = 0x11;
+#[allow(dead_code)]
+pub(crate) const SPDM_VER_12: u8 = 0x12;
+#[allow(dead_code)]
+pub(crate) const SPDM_VER_13: u8 = 0x13;
+pub(crate) const SPDM_VER_14: u8 = 0x14;
 
 pub(crate) const SPDM_MIN_VER: u8 = SPDM_VER_10;
+pub(crate) const SPDM_MAX_VER: u8 = SPDM_VER_14;
 
-#[allow(dead_code)]
 pub(crate) const SPDM_REQ: u8 = 0x80;
-#[allow(dead_code)]
 pub(crate) const SPDM_ERROR: u8 = 0x7f;
 
 #[derive(Clone, Copy)]
@@ -90,3 +98,7 @@ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         write!(f, "{:#x}", *self as u8)
     }
 }
+
+pub(crate) const SPDM_GET_VERSION: u8 = 0x84;
+pub(crate) const SPDM_GET_VERSION_LEN: usize =
+    mem::size_of::<GetVersionRsp>() + (u8::MAX as usize) * mem::size_of::<u16>();
diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
index 1883579b817a..58d86ea06fd9 100644
--- a/lib/rspdm/lib.rs
+++ b/lib/rspdm/lib.rs
@@ -18,8 +18,10 @@
     c_int,
     c_void, //
 };
+use core::pin::Pin;
 use core::ptr;
 use kernel::prelude::*;
+use kernel::sync::{new_mutex, Mutex};
 use kernel::{
     alloc::flags,
     bindings, //
@@ -51,11 +53,22 @@ pub extern "C" fn spdm_create(
     transport_sz: u32,
     validate: bindings::spdm_validate,
 ) -> *mut spdm_state {
-    match KBox::new(
-        SpdmState::new(dev, transport, transport_priv, transport_sz, validate),
-        flags::GFP_KERNEL,
-    ) {
-        Ok(ret) => KBox::into_raw(ret) as *mut spdm_state,
+    // Wrap the `SpdmState` in a `Mutex` so that concurrent FFI callers (for
+    // example, two threads racing on `spdm_authenticate()` for the same
+    // device) serialize on the lock and never form aliased `&mut SpdmState`
+    // references.
+    let state = SpdmState::new(dev, transport, transport_priv, transport_sz, validate);
+    match KBox::pin_init(new_mutex!(state), flags::GFP_KERNEL) {
+        Ok(b) => {
+            // `Mutex<SpdmState>` is `!Unpin` and must remain pinned in
+            // memory.  The C side stores the raw pointer; `spdm_destroy()`
+            // re-pins via `Pin::new_unchecked` before dropping, preserving
+            // the pin invariant.
+            // SAFETY: The contents are not moved between here and the
+            // matching `KBox::from_raw` in `spdm_destroy()`.
+            let raw = KBox::into_raw(unsafe { Pin::into_inner_unchecked(b) });
+            raw as *mut spdm_state
+        }
         Err(_) => ptr::null_mut(),
     }
 }
@@ -70,7 +83,25 @@ pub extern "C" fn spdm_create(
 /// Return 0 on success or a negative errno.  In particular, -EPROTONOSUPPORT
 /// indicates authentication is not supported by the device.
 #[export]
-pub extern "C" fn spdm_authenticate(_state_ptr: *mut spdm_state) -> c_int {
+pub extern "C" fn spdm_authenticate(state_ptr: *mut spdm_state) -> c_int {
+    if state_ptr.is_null() {
+        return -(bindings::EINVAL as c_int);
+    }
+
+    // SAFETY: `state_ptr` was returned from `spdm_create()` (which leaks a
+    // `Pin<KBox<Mutex<SpdmState>>>`) and has not yet been passed to
+    // `spdm_destroy()`.  We only form a shared reference to the mutex; the
+    // exclusive `&mut SpdmState` lives entirely inside the lock guard, so
+    // concurrent FFI callers serialize on the mutex and can never form
+    // aliased `&mut SpdmState` references.
+    let mutex: &Mutex<SpdmState> = unsafe { &*(state_ptr as *const Mutex<SpdmState>) };
+
+    let mut state = mutex.lock();
+
+    if let Err(e) = state.get_version() {
+        return e.to_errno() as c_int;
+    }
+
     -(EPROTONOSUPPORT as i32)
 }
 
@@ -82,8 +113,11 @@ pub extern "C" fn spdm_destroy(state_ptr: *mut spdm_state) {
     if state_ptr.is_null() {
         return;
     }
-    // SAFETY: `state_ptr` was returned from `spdm_create` (which uses
-    // `KBox::into_raw`) and the caller guarantees the state is no longer
-    // in use.  Reconstructing the `KBox` and dropping it frees the state.
-    drop(unsafe { KBox::from_raw(state_ptr as *mut SpdmState) });
+    // SAFETY: `state_ptr` was returned from `spdm_create()`, which leaked a
+    // `Pin<KBox<Mutex<SpdmState>>>` via `KBox::into_raw`.  The caller
+    // guarantees the state is no longer in use.  Reconstructing the pinned
+    // box and dropping it runs `Drop` for the `Mutex` and `SpdmState` and
+    // frees the allocation.
+    let b = unsafe { KBox::from_raw(state_ptr as *mut Mutex<SpdmState>) };
+    drop(unsafe { Pin::new_unchecked(b) });
 }
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
index e1f74d19ac4b..9e8c65a12199 100644
--- a/lib/rspdm/state.rs
+++ b/lib/rspdm/state.rs
@@ -8,6 +8,7 @@
 //! <https://www.dmtf.org/dsp/DSP0274>
 
 use core::ffi::c_void;
+use core::slice::from_raw_parts_mut;
 use kernel::prelude::*;
 use kernel::{
     bindings,
@@ -22,10 +23,14 @@
 use crate::consts::{
     SpdmErrorCode,
     SPDM_ERROR,
+    SPDM_GET_VERSION_LEN,
+    SPDM_MAX_VER,
     SPDM_MIN_VER,
     SPDM_REQ, //
 };
 use crate::validator::{
+    GetVersionReq,
+    GetVersionRsp,
     SpdmErrorRsp,
     SpdmHeader, //
 };
@@ -33,6 +38,11 @@
 /// The current SPDM session state for a device. Based on the
 /// C `struct spdm_state`.
 ///
+/// Concurrent access is serialized by wrapping the whole struct in a
+/// `Mutex<SpdmState>` at the FFI boundary, so `spdm_authenticate()` callers
+/// run one at a time and the locked `&mut SpdmState` is the only way to
+/// reach the inner fields.
+///
 /// `dev`: Responder device.  Used for error reporting and passed to @transport.
 /// `transport`: Transport function to perform one message exchange.
 /// `transport_priv`: Transport private data.
@@ -72,7 +82,6 @@ pub(crate) fn new(
         }
     }
 
-    #[allow(dead_code)]
     fn spdm_err(&self, rsp: &SpdmErrorRsp) -> Result<(), Error> {
         match rsp.error_code {
             SpdmErrorCode::InvalidRequest => {
@@ -184,7 +193,6 @@ fn spdm_err(&self, rsp: &SpdmErrorRsp) -> Result<(), Error> {
     ///
     /// The data in `request_buf` is sent to the device and the response is
     /// stored in `response_buf`.
-    #[allow(dead_code)]
     pub(crate) fn spdm_exchange(
         &self,
         request_buf: &mut [u8],
@@ -234,4 +242,59 @@ pub(crate) fn spdm_exchange(
 
         Ok(length)
     }
+
+    /// Negotiate a supported SPDM version and store the information
+    /// in the `SpdmState`.
+    pub(crate) fn get_version(&mut self) -> Result<(), Error> {
+        let mut request = GetVersionReq::default();
+        request.version = SPDM_MIN_VER;
+        self.version = SPDM_MIN_VER;
+
+        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
+        let request_buf = unsafe {
+            from_raw_parts_mut(
+                &mut request as *mut _ as *mut u8,
+                core::mem::size_of::<GetVersionReq>(),
+            )
+        };
+
+        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, SPDM_GET_VERSION_LEN, GFP_KERNEL)?;
+
+        let rc = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
+
+        // The transport must report a length within the buffer we provided.
+        if rc > response_vec.len() {
+            return Err(EINVAL);
+        }
+        response_vec.truncate(rc);
+
+        let response: &GetVersionRsp = Untrusted::new(response_vec.as_slice()).validate()?;
+
+        let mut foundver = false;
+        let entry_count = response.version_number_entry_count;
+        let entries_offset = core::mem::offset_of!(GetVersionRsp, version_number_entries);
+
+        for i in 0..entry_count as usize {
+            let off = entries_offset + i * core::mem::size_of::<u16>();
+            let entry = u16::from_le_bytes([response_vec[off], response_vec[off + 1]]);
+            let alpha_version = (entry & 0xF) as u8;
+            let version = (entry >> 8) as u8;
+
+            if alpha_version > 0 {
+                pr_warn!("Alpha version {alpha_version} is not specifically supported\n");
+            }
+
+            if version >= self.version && version <= SPDM_MAX_VER {
+                self.version = version;
+                foundver = true;
+            }
+        }
+
+        if !foundver {
+            pr_err!("No common supported version\n");
+            return Err(EPROTO);
+        }
+
+        Ok(())
+    }
 }
diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
index 323242e84580..5990ff7ada29 100644
--- a/lib/rspdm/validator.rs
+++ b/lib/rspdm/validator.rs
@@ -7,6 +7,10 @@
 //! Rust implementation of the DMTF Security Protocol and Data Model (SPDM)
 //! <https://www.dmtf.org/dsp/DSP0274>
 
+use crate::bindings::{
+    __IncompleteArrayField,
+    __le16, //
+};
 use crate::consts::SpdmErrorCode;
 use core::mem;
 use kernel::prelude::*;
@@ -21,6 +25,11 @@
     },
 };
 
+use crate::consts::{
+    SPDM_GET_VERSION,
+    SPDM_MIN_VER, //
+};
+
 #[repr(C, packed)]
 pub(crate) struct SpdmHeader {
     pub(crate) version: u8,
@@ -90,3 +99,63 @@ fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
         Ok(unsafe { &*ptr })
     }
 }
+
+#[repr(C, packed)]
+pub(crate) struct GetVersionReq {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+}
+
+impl Default for GetVersionReq {
+    fn default() -> Self {
+        GetVersionReq {
+            version: 0,
+            code: SPDM_GET_VERSION,
+            param1: 0,
+            param2: 0,
+        }
+    }
+}
+
+#[repr(C, packed)]
+pub(crate) struct GetVersionRsp {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    param1: u8,
+    param2: u8,
+    reserved: u8,
+    pub(crate) version_number_entry_count: u8,
+    pub(crate) version_number_entries: __IncompleteArrayField<__le16>,
+}
+
+impl<'a> Validate<Untrusted<&'a [u8]>> for &'a GetVersionRsp {
+    type Err = Error;
+
+    fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
+        if unvalidated.len() < mem::size_of::<GetVersionRsp>() {
+            return Err(EINVAL);
+        }
+
+        let version = *(unvalidated.get(0).ok_or(ENOMEM))? as usize;
+        if version != SPDM_MIN_VER.into() {
+            return Err(EINVAL);
+        }
+
+        let version_number_entries = *(unvalidated.get(5).ok_or(ENOMEM))? as usize;
+        let total_expected_size =
+            version_number_entries * mem::size_of::<__le16>() + mem::size_of::<GetVersionRsp>();
+        if unvalidated.len() < total_expected_size {
+            return Err(EINVAL);
+        }
+
+        let ptr = unvalidated.as_ptr();
+        // CAST: `GetVersionRsp` only contains integers and has `repr(C)`.
+        let ptr = ptr.cast::<GetVersionRsp>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        let rsp: &GetVersionRsp = unsafe { &*ptr };
+
+        Ok(rsp)
+    }
+}
-- 
2.55.0

[PATCH v3 15/21] lib: rspdm: Support SPDM get_capabilities

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

Support the GET_CAPABILITIES SPDM command.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 lib/rspdm/consts.rs    |  19 +++++++-
 lib/rspdm/lib.rs       |   4 ++
 lib/rspdm/state.rs     |  78 ++++++++++++++++++++++++++++-
 lib/rspdm/validator.rs | 108 ++++++++++++++++++++++++++++++++++++++++-
 4 files changed, 205 insertions(+), 4 deletions(-)

diff --git a/lib/rspdm/consts.rs b/lib/rspdm/consts.rs
index 055671d43abd..15d69631ed8c 100644
--- a/lib/rspdm/consts.rs
+++ b/lib/rspdm/consts.rs
@@ -9,13 +9,12 @@
 
 use crate::validator::GetVersionRsp;
 use core::mem;
+use kernel::bits::bit_u32;
 use kernel::error::{code::EINVAL, Error};
 
 // SPDM versions supported by this implementation
 pub(crate) const SPDM_VER_10: u8 = 0x10;
-#[allow(dead_code)]
 pub(crate) const SPDM_VER_11: u8 = 0x11;
-#[allow(dead_code)]
 pub(crate) const SPDM_VER_12: u8 = 0x12;
 #[allow(dead_code)]
 pub(crate) const SPDM_VER_13: u8 = 0x13;
@@ -102,3 +101,19 @@ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 pub(crate) const SPDM_GET_VERSION: u8 = 0x84;
 pub(crate) const SPDM_GET_VERSION_LEN: usize =
     mem::size_of::<GetVersionRsp>() + (u8::MAX as usize) * mem::size_of::<u16>();
+
+pub(crate) const SPDM_GET_CAPABILITIES: u8 = 0xe1;
+pub(crate) const SPDM_MIN_DATA_TRANSFER_SIZE: u32 = 42;
+
+// SPDM cryptographic timeout of this implementation:
+// Assume calculations may take up to 1 sec on a busy machine, which equals
+// roughly 1 << 20.  That's within the limits mandated for responders by CMA
+// (1 << 23 usec, PCIe r6.2 sec 6.31.3) and DOE (1 sec, PCIe r6.2 sec 6.30.2).
+// Used in GET_CAPABILITIES exchange.
+pub(crate) const SPDM_CTEXPONENT: u8 = 20;
+
+pub(crate) const SPDM_CERT_CAP: u32 = bit_u32(1);
+pub(crate) const SPDM_CHAL_CAP: u32 = bit_u32(2);
+
+pub(crate) const SPDM_REQ_CAPS: u32 = SPDM_CERT_CAP | SPDM_CHAL_CAP;
+pub(crate) const SPDM_RSP_MIN_CAPS: u32 = SPDM_CERT_CAP | SPDM_CHAL_CAP;
diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
index 58d86ea06fd9..76325babdff2 100644
--- a/lib/rspdm/lib.rs
+++ b/lib/rspdm/lib.rs
@@ -102,6 +102,10 @@ pub extern "C" fn spdm_authenticate(state_ptr: *mut spdm_state) -> c_int {
         return e.to_errno() as c_int;
     }
 
+    if let Err(e) = state.get_capabilities() {
+        return e.to_errno() as c_int;
+    }
+
     -(EPROTONOSUPPORT as i32)
 }
 
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
index 9e8c65a12199..5ef14c8ed237 100644
--- a/lib/rspdm/state.rs
+++ b/lib/rspdm/state.rs
@@ -25,10 +25,17 @@
     SPDM_ERROR,
     SPDM_GET_VERSION_LEN,
     SPDM_MAX_VER,
+    SPDM_MIN_DATA_TRANSFER_SIZE,
     SPDM_MIN_VER,
-    SPDM_REQ, //
+    SPDM_REQ,
+    SPDM_RSP_MIN_CAPS,
+    SPDM_VER_10,
+    SPDM_VER_11,
+    SPDM_VER_12, //
 };
 use crate::validator::{
+    GetCapabilitiesReq,
+    GetCapabilitiesRsp,
     GetVersionReq,
     GetVersionRsp,
     SpdmErrorRsp,
@@ -52,6 +59,8 @@
 ///
 /// `version`: Maximum common supported version of requester and responder.
 ///  Negotiated during GET_VERSION exchange.
+/// `rsp_caps`: Cached capabilities of responder.
+///  Received during GET_CAPABILITIES exchange.
 #[expect(dead_code)]
 pub(crate) struct SpdmState {
     pub(crate) dev: *mut bindings::device,
@@ -62,6 +71,7 @@ pub(crate) struct SpdmState {
 
     // Negotiated state
     pub(crate) version: u8,
+    pub(crate) rsp_caps: u32,
 }
 
 impl SpdmState {
@@ -79,6 +89,7 @@ pub(crate) fn new(
             transport_sz,
             validate,
             version: SPDM_MIN_VER,
+            rsp_caps: 0,
         }
     }
 
@@ -297,4 +308,69 @@ pub(crate) fn get_version(&mut self) -> Result<(), Error> {
 
         Ok(())
     }
+
+    /// Obtain the supported capabilities from an SPDM session and store the
+    /// information in the `SpdmState`.
+    pub(crate) fn get_capabilities(&mut self) -> Result<(), Error> {
+        let mut request = GetCapabilitiesReq::default();
+        request.version = self.version;
+
+        let (req_sz, rsp_sz) = match self.version {
+            SPDM_VER_10 => (
+                core::mem::size_of::<SpdmHeader>(),
+                core::mem::size_of::<SpdmHeader>() + 4 + core::mem::size_of::<u32>(),
+            ),
+            SPDM_VER_11 => {
+                let len = core::mem::size_of::<SpdmHeader>() + 4 + core::mem::size_of::<u32>();
+                (len, len)
+            }
+            _ => {
+                request.data_transfer_size = self.transport_sz.to_le();
+                request.max_spdm_msg_size = request.data_transfer_size;
+
+                (
+                    core::mem::size_of::<GetCapabilitiesReq>(),
+                    core::mem::size_of::<GetCapabilitiesRsp>(),
+                )
+            }
+        };
+
+        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
+        let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
+
+        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, rsp_sz, GFP_KERNEL)?;
+
+        let rc = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
+
+        // The transport must report a length within the buffer we provided.
+        if rc > response_vec.len() {
+            pr_err!("Overflowed capabilities response\n");
+            return Err(EIO);
+        }
+        response_vec.truncate(rc);
+
+        let response: &mut GetCapabilitiesRsp = Untrusted::new(&mut response_vec).validate()?;
+
+        self.rsp_caps = u32::from_le(response.flags);
+        if (self.rsp_caps & SPDM_RSP_MIN_CAPS) != SPDM_RSP_MIN_CAPS {
+            pr_err!(
+                "{:#x} capabilities are supported, which don't meet required {:#x}\n",
+                self.rsp_caps,
+                SPDM_RSP_MIN_CAPS
+            );
+            self.rsp_caps = 0;
+            return Err(EPROTONOSUPPORT);
+        }
+
+        if self.version >= SPDM_VER_12 {
+            let data_transfer_size = u32::from_le(response.data_transfer_size);
+            if data_transfer_size < SPDM_MIN_DATA_TRANSFER_SIZE {
+                pr_err!("Malformed capabilities response\n");
+                return Err(EPROTO);
+            }
+            self.transport_sz = self.transport_sz.min(data_transfer_size);
+        }
+
+        Ok(())
+    }
 }
diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
index 5990ff7ada29..42c0b28cdcaa 100644
--- a/lib/rspdm/validator.rs
+++ b/lib/rspdm/validator.rs
@@ -26,8 +26,13 @@
 };
 
 use crate::consts::{
+    SPDM_CTEXPONENT,
+    SPDM_GET_CAPABILITIES,
     SPDM_GET_VERSION,
-    SPDM_MIN_VER, //
+    SPDM_MIN_VER,
+    SPDM_REQ_CAPS,
+    SPDM_VER_10,
+    SPDM_VER_11, //
 };
 
 #[repr(C, packed)]
@@ -159,3 +164,104 @@ fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
         Ok(rsp)
     }
 }
+
+#[repr(C, packed)]
+pub(crate) struct GetCapabilitiesReq {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+
+    reserved1: u8,
+    pub(crate) ctexponent: u8,
+    reserved2: [u8; 2],
+
+    pub(crate) flags: u32,
+
+    /* End of SPDM 1.1 structure */
+    pub(crate) data_transfer_size: u32,
+    pub(crate) max_spdm_msg_size: u32,
+}
+
+impl Default for GetCapabilitiesReq {
+    fn default() -> Self {
+        GetCapabilitiesReq {
+            version: 0,
+            code: SPDM_GET_CAPABILITIES,
+            param1: 0,
+            param2: 0,
+            reserved1: 0,
+            ctexponent: SPDM_CTEXPONENT,
+            reserved2: [0; 2],
+            flags: SPDM_REQ_CAPS.to_le(),
+            data_transfer_size: 0,
+            max_spdm_msg_size: 0,
+        }
+    }
+}
+
+#[repr(C, packed)]
+pub(crate) struct GetCapabilitiesRsp {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    param2: u8,
+
+    reserved1: u8,
+    pub(crate) ctexponent: u8,
+    reserved2: [u8; 2],
+
+    pub(crate) flags: u32,
+
+    /* End of SPDM 1.1 structure */
+    pub(crate) data_transfer_size: u32,
+    pub(crate) max_spdm_msg_size: u32,
+
+    pub(crate) supported_algorithms: __IncompleteArrayField<__le16>,
+}
+
+impl<'a> Validate<Untrusted<&'a mut KVec<u8>>> for &'a mut GetCapabilitiesRsp {
+    type Err = Error;
+
+    fn validate(unvalidated: &mut KVec<u8>) -> Result<Self, Self::Err> {
+        let version = *(unvalidated.get(0).ok_or(EINVAL))?;
+
+        let expected_length = match version {
+            SPDM_VER_10 | SPDM_VER_11 => {
+                core::mem::size_of::<SpdmHeader>() + 4 + core::mem::size_of::<u32>()
+            }
+            _ => {
+                // Check to see if param1 is set
+                if *(unvalidated.get(2).ok_or(EINVAL))? == 0 {
+                    mem::size_of::<GetCapabilitiesRsp>()
+                        - mem::size_of::<__IncompleteArrayField<__le16>>()
+                } else {
+                    // Not currently supported by Linux, we don't set the bit
+                    // so the responder shouldn't either.
+                    return Err(EINVAL);
+                }
+            }
+        };
+
+        // Make sure the response meets the SPDM spec version requirements
+        if unvalidated.len() < expected_length {
+            return Err(EINVAL);
+        }
+
+        // If the response is shorter than GetCapabilitiesRsp
+        // (which is valid for older spec versions and when param1 is
+        // set to 0) then we need to pad the vector to ensure
+        // GetCapabilitiesRsp will be initialised.
+        while unvalidated.len() < mem::size_of::<GetCapabilitiesRsp>() {
+            unvalidated.push(0, GFP_KERNEL)?;
+        }
+
+        let ptr = unvalidated.as_mut_ptr();
+        // CAST: `GetCapabilitiesRsp` only contains integers and has `repr(C)`.
+        let ptr = ptr.cast::<GetCapabilitiesRsp>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        let rsp: &mut GetCapabilitiesRsp = unsafe { &mut *ptr };
+
+        Ok(rsp)
+    }
+}
-- 
2.55.0

[PATCH v3 16/21] lib: rspdm: Support SPDM negotiate_algorithms

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

Support the NEGOTIATE_ALGORITHMS SPDM command.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 lib/rspdm/consts.rs    |  56 +++++++++-
 lib/rspdm/lib.rs       |   9 +-
 lib/rspdm/state.rs     | 243 ++++++++++++++++++++++++++++++++++++++++-
 lib/rspdm/validator.rs | 110 ++++++++++++++++++-
 4 files changed, 412 insertions(+), 6 deletions(-)

diff --git a/lib/rspdm/consts.rs b/lib/rspdm/consts.rs
index 15d69631ed8c..e222821bad5d 100644
--- a/lib/rspdm/consts.rs
+++ b/lib/rspdm/consts.rs
@@ -9,7 +9,10 @@
 
 use crate::validator::GetVersionRsp;
 use core::mem;
-use kernel::bits::bit_u32;
+use kernel::bits::{
+    bit_u32,
+    bit_u8, //
+};
 use kernel::error::{code::EINVAL, Error};
 
 // SPDM versions supported by this implementation
@@ -114,6 +117,57 @@ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 
 pub(crate) const SPDM_CERT_CAP: u32 = bit_u32(1);
 pub(crate) const SPDM_CHAL_CAP: u32 = bit_u32(2);
+pub(crate) const SPDM_KEY_EX_CAP: u32 = bit_u32(9);
 
 pub(crate) const SPDM_REQ_CAPS: u32 = SPDM_CERT_CAP | SPDM_CHAL_CAP;
 pub(crate) const SPDM_RSP_MIN_CAPS: u32 = SPDM_CERT_CAP | SPDM_CHAL_CAP;
+
+pub(crate) const SPDM_NEGOTIATE_ALGS: u8 = 0xe3;
+
+pub(crate) const SPDM_MEAS_SPEC_DMTF: u8 = bit_u8(0);
+
+pub(crate) const SPDM_ASYM_RSASSA_2048: u32 = bit_u32(0);
+pub(crate) const _SPDM_ASYM_RSAPSS_2048: u32 = bit_u32(1);
+pub(crate) const SPDM_ASYM_RSASSA_3072: u32 = bit_u32(2);
+pub(crate) const _SPDM_ASYM_RSAPSS_3072: u32 = bit_u32(3);
+pub(crate) const SPDM_ASYM_ECDSA_ECC_NIST_P256: u32 = bit_u32(4);
+pub(crate) const SPDM_ASYM_RSASSA_4096: u32 = bit_u32(5);
+pub(crate) const _SPDM_ASYM_RSAPSS_4096: u32 = bit_u32(6);
+pub(crate) const SPDM_ASYM_ECDSA_ECC_NIST_P384: u32 = bit_u32(7);
+pub(crate) const SPDM_ASYM_ECDSA_ECC_NIST_P521: u32 = bit_u32(8);
+pub(crate) const _SPDM_ASYM_SM2_ECC_SM2_P256: u32 = bit_u32(9);
+pub(crate) const _SPDM_ASYM_EDDSA_ED25519: u32 = bit_u32(10);
+pub(crate) const _SPDM_ASYM_EDDSA_ED448: u32 = bit_u32(11);
+
+pub(crate) const SPDM_HASH_SHA_256: u32 = bit_u32(0);
+pub(crate) const SPDM_HASH_SHA_384: u32 = bit_u32(1);
+pub(crate) const SPDM_HASH_SHA_512: u32 = bit_u32(2);
+
+// If the crypto support isn't enabled don't offer the algorithms
+// to the responder
+#[cfg(CONFIG_CRYPTO_RSA)]
+pub(crate) const SPDM_ASYM_RSA: u32 =
+    SPDM_ASYM_RSASSA_2048 | SPDM_ASYM_RSASSA_3072 | SPDM_ASYM_RSASSA_4096;
+#[cfg(not(CONFIG_CRYPTO_RSA))]
+pub(crate) const SPDM_ASYM_RSA: u32 = 0;
+
+#[cfg(CONFIG_CRYPTO_ECDSA)]
+pub(crate) const SPDM_ASYM_ECDSA: u32 =
+    SPDM_ASYM_ECDSA_ECC_NIST_P256 | SPDM_ASYM_ECDSA_ECC_NIST_P384 | SPDM_ASYM_ECDSA_ECC_NIST_P521;
+#[cfg(not(CONFIG_CRYPTO_ECDSA))]
+pub(crate) const SPDM_ASYM_ECDSA: u32 = 0;
+
+#[cfg(CONFIG_CRYPTO_SHA256)]
+pub(crate) const SPDM_HASH_SHA2_256: u32 = SPDM_HASH_SHA_256;
+#[cfg(not(CONFIG_CRYPTO_SHA256))]
+pub(crate) const SPDM_HASH_SHA2_256: u32 = 0;
+
+#[cfg(CONFIG_CRYPTO_SHA512)]
+pub(crate) const SPDM_HASH_SHA2_384_512: u32 = SPDM_HASH_SHA_384 | SPDM_HASH_SHA_512;
+#[cfg(not(CONFIG_CRYPTO_SHA512))]
+pub(crate) const SPDM_HASH_SHA2_384_512: u32 = 0;
+
+pub(crate) const SPDM_ASYM_ALGOS: u32 = SPDM_ASYM_RSA | SPDM_ASYM_ECDSA;
+pub(crate) const SPDM_HASH_ALGOS: u32 = SPDM_HASH_SHA2_256 | SPDM_HASH_SHA2_384_512;
+
+pub(crate) const SPDM_OPAQUE_DATA_FMT_GENERAL: u8 = bit_u8(1);
diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
index 76325babdff2..d418d15e4c70 100644
--- a/lib/rspdm/lib.rs
+++ b/lib/rspdm/lib.rs
@@ -94,7 +94,7 @@ pub extern "C" fn spdm_authenticate(state_ptr: *mut spdm_state) -> c_int {
     // exclusive `&mut SpdmState` lives entirely inside the lock guard, so
     // concurrent FFI callers serialize on the mutex and can never form
     // aliased `&mut SpdmState` references.
-    let mutex: &Mutex<SpdmState> = unsafe { &*(state_ptr as *const Mutex<SpdmState>) };
+    let mutex: &Mutex<SpdmState<'_>> = unsafe { &*(state_ptr as *const Mutex<SpdmState<'_>>) };
 
     let mut state = mutex.lock();
 
@@ -106,6 +106,10 @@ pub extern "C" fn spdm_authenticate(state_ptr: *mut spdm_state) -> c_int {
         return e.to_errno() as c_int;
     }
 
+    if let Err(e) = state.negotiate_algs() {
+        return e.to_errno() as c_int;
+    }
+
     -(EPROTONOSUPPORT as i32)
 }
 
@@ -117,11 +121,12 @@ pub extern "C" fn spdm_destroy(state_ptr: *mut spdm_state) {
     if state_ptr.is_null() {
         return;
     }
+
     // SAFETY: `state_ptr` was returned from `spdm_create()`, which leaked a
     // `Pin<KBox<Mutex<SpdmState>>>` via `KBox::into_raw`.  The caller
     // guarantees the state is no longer in use.  Reconstructing the pinned
     // box and dropping it runs `Drop` for the `Mutex` and `SpdmState` and
     // frees the allocation.
-    let b = unsafe { KBox::from_raw(state_ptr as *mut Mutex<SpdmState>) };
+    let b = unsafe { KBox::from_raw(state_ptr as *mut Mutex<SpdmState<'_>>) };
     drop(unsafe { Pin::new_unchecked(b) });
 }
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
index 5ef14c8ed237..b78086c75370 100644
--- a/lib/rspdm/state.rs
+++ b/lib/rspdm/state.rs
@@ -14,19 +14,34 @@
     bindings,
     error::{
         code::EINVAL,
+        from_err_ptr,
         to_result,
         Error, //
     },
+    str::CStr,
     validate::Untrusted,
 };
 
 use crate::consts::{
     SpdmErrorCode,
+    SPDM_ASYM_ALGOS,
+    SPDM_ASYM_ECDSA_ECC_NIST_P256,
+    SPDM_ASYM_ECDSA_ECC_NIST_P384,
+    SPDM_ASYM_ECDSA_ECC_NIST_P521,
+    SPDM_ASYM_RSASSA_2048,
+    SPDM_ASYM_RSASSA_3072,
+    SPDM_ASYM_RSASSA_4096,
     SPDM_ERROR,
     SPDM_GET_VERSION_LEN,
+    SPDM_HASH_ALGOS,
+    SPDM_HASH_SHA_256,
+    SPDM_HASH_SHA_384,
+    SPDM_HASH_SHA_512,
+    SPDM_KEY_EX_CAP,
     SPDM_MAX_VER,
     SPDM_MIN_DATA_TRANSFER_SIZE,
     SPDM_MIN_VER,
+    SPDM_OPAQUE_DATA_FMT_GENERAL,
     SPDM_REQ,
     SPDM_RSP_MIN_CAPS,
     SPDM_VER_10,
@@ -38,6 +53,8 @@
     GetCapabilitiesRsp,
     GetVersionReq,
     GetVersionRsp,
+    NegotiateAlgsReq,
+    NegotiateAlgsRsp,
     SpdmErrorRsp,
     SpdmHeader, //
 };
@@ -61,8 +78,27 @@
 ///  Negotiated during GET_VERSION exchange.
 /// `rsp_caps`: Cached capabilities of responder.
 ///  Received during GET_CAPABILITIES exchange.
+/// @base_asym_alg: Asymmetric key algorithm for signature verification of
+///  CHALLENGE_AUTH and MEASUREMENTS messages.
+///  Selected by responder during NEGOTIATE_ALGORITHMS exchange.
+/// @base_hash_alg: Hash algorithm for signature verification of
+///  CHALLENGE_AUTH and MEASUREMENTS messages.
+///  Selected by responder during NEGOTIATE_ALGORITHMS exchange.
+/// @meas_hash_alg: Hash algorithm for measurement blocks.
+///  Selected by responder during NEGOTIATE_ALGORITHMS exchange.
+/// @base_asym_enc: Human-readable name of @base_asym_alg's signature encoding.
+///  Passed to crypto subsystem when calling verify_signature().
+/// @sig_len: Signature length of @base_asym_alg (in bytes).
+///  S or SigLen in SPDM specification.
+/// @base_hash_alg_name: Human-readable name of @base_hash_alg.
+///  Passed to crypto subsystem when calling crypto_alloc_shash() and
+///  verify_signature().
+/// @shash: Synchronous hash handle for @base_hash_alg computation.
+/// @desc: Synchronous hash context for @base_hash_alg computation.
+/// @hash_len: Hash length of @base_hash_alg (in bytes).
+///  H in SPDM specification.
 #[expect(dead_code)]
-pub(crate) struct SpdmState {
+pub(crate) struct SpdmState<'a> {
     pub(crate) dev: *mut bindings::device,
     pub(crate) transport: bindings::spdm_transport,
     pub(crate) transport_priv: *mut c_void,
@@ -72,9 +108,43 @@ pub(crate) struct SpdmState {
     // Negotiated state
     pub(crate) version: u8,
     pub(crate) rsp_caps: u32,
+    pub(crate) base_asym_alg: u32,
+    pub(crate) base_hash_alg: u32,
+    pub(crate) meas_hash_alg: u32,
+
+    /* Signature algorithm */
+    base_asym_enc: &'a CStr,
+    sig_len: usize,
+
+    /* Hash algorithm */
+    base_hash_alg_name: &'a CStr,
+    pub(crate) shash: *mut bindings::crypto_shash,
+    pub(crate) desc: Option<&'a mut bindings::shash_desc>,
+    pub(crate) hash_len: usize,
 }
 
-impl SpdmState {
+impl Drop for SpdmState<'_> {
+    fn drop(&mut self) {
+        if let Some(desc) = self.desc.take() {
+            // SAFETY: `self.shash` is a valid handle
+            let desc_len = core::mem::size_of::<bindings::shash_desc>()
+                + unsafe { bindings::crypto_shash_descsize(self.shash) } as usize;
+
+            // SAFETY: `desc` was allocated as a KVec<u8> with a length of `desc_len`
+            // and then transmuted to a raw pointer with into_raw_parts()
+            let desc_ptr =
+                unsafe { core::mem::transmute::<&mut bindings::shash_desc, *mut u8>(desc) };
+            let desc_vec = unsafe { KVec::<u8>::from_raw_parts(desc_ptr, desc_len, desc_len) };
+            drop(desc_vec);
+        }
+
+        unsafe {
+            bindings::crypto_free_shash(self.shash);
+        }
+    }
+}
+
+impl SpdmState<'_> {
     pub(crate) fn new(
         dev: *mut bindings::device,
         transport: bindings::spdm_transport,
@@ -90,6 +160,15 @@ pub(crate) fn new(
             validate,
             version: SPDM_MIN_VER,
             rsp_caps: 0,
+            base_asym_alg: 0,
+            base_hash_alg: 0,
+            meas_hash_alg: 0,
+            base_asym_enc: unsafe { CStr::from_bytes_with_nul_unchecked(b"\0") },
+            sig_len: 0,
+            base_hash_alg_name: unsafe { CStr::from_bytes_with_nul_unchecked(b"\0") },
+            shash: core::ptr::null_mut(),
+            desc: None,
+            hash_len: 0,
         }
     }
 
@@ -373,4 +452,164 @@ pub(crate) fn get_capabilities(&mut self) -> Result<(), Error> {
 
         Ok(())
     }
+
+    fn update_response_algs(&mut self) -> Result<(), Error> {
+        match self.base_asym_alg {
+            SPDM_ASYM_RSASSA_2048 => {
+                self.sig_len = 256;
+                self.base_asym_enc = CStr::from_bytes_with_nul(b"pkcs1\0")?;
+            }
+            SPDM_ASYM_RSASSA_3072 => {
+                self.sig_len = 384;
+                self.base_asym_enc = CStr::from_bytes_with_nul(b"pkcs1\0")?;
+            }
+            SPDM_ASYM_RSASSA_4096 => {
+                self.sig_len = 512;
+                self.base_asym_enc = CStr::from_bytes_with_nul(b"pkcs1\0")?;
+            }
+            SPDM_ASYM_ECDSA_ECC_NIST_P256 => {
+                self.sig_len = 64;
+                self.base_asym_enc = CStr::from_bytes_with_nul(b"p1363\0")?;
+            }
+            SPDM_ASYM_ECDSA_ECC_NIST_P384 => {
+                self.sig_len = 96;
+                self.base_asym_enc = CStr::from_bytes_with_nul(b"p1363\0")?;
+            }
+            SPDM_ASYM_ECDSA_ECC_NIST_P521 => {
+                self.sig_len = 132;
+                self.base_asym_enc = CStr::from_bytes_with_nul(b"p1363\0")?;
+            }
+            _ => {
+                pr_err!("Unknown asym algorithm\n");
+                return Err(EINVAL);
+            }
+        }
+
+        match self.base_hash_alg {
+            SPDM_HASH_SHA_256 => {
+                self.base_hash_alg_name = CStr::from_bytes_with_nul(b"sha256\0")?;
+            }
+            SPDM_HASH_SHA_384 => {
+                self.base_hash_alg_name = CStr::from_bytes_with_nul(b"sha384\0")?;
+            }
+            SPDM_HASH_SHA_512 => {
+                self.base_hash_alg_name = CStr::from_bytes_with_nul(b"sha512\0")?;
+            }
+            _ => {
+                pr_err!("Unknown hash algorithm\n");
+                return Err(EINVAL);
+            }
+        }
+
+        // This is freed in when `SpdmState` is dropped, but this call
+        // can happen multiple times.
+        if self.shash != core::ptr::null_mut() {
+            if let Some(desc) = self.desc.take() {
+                // SAFETY: `self.shash` is a valid handle
+                let desc_len = core::mem::size_of::<bindings::shash_desc>()
+                    + unsafe { bindings::crypto_shash_descsize(self.shash) } as usize;
+
+                // SAFETY: `desc` was allocated as a KVec<u8> with a length of `desc_len`
+                // and then transmuted to a raw pointer with into_raw_parts()
+                let desc_ptr =
+                    unsafe { core::mem::transmute::<&mut bindings::shash_desc, *mut u8>(desc) };
+                let desc_vec = unsafe { KVec::<u8>::from_raw_parts(desc_ptr, desc_len, desc_len) };
+                drop(desc_vec);
+            }
+
+            unsafe {
+                bindings::crypto_free_shash(self.shash);
+            }
+        }
+
+        self.shash =
+            unsafe { bindings::crypto_alloc_shash(self.base_hash_alg_name.as_char_ptr(), 0, 0) };
+        if let Err(e) = from_err_ptr(self.shash) {
+            self.shash = core::ptr::null_mut();
+            return Err(e);
+        }
+
+        // SAFETY: `self.shash` is a valid handle (verified above).
+        let desc_len = core::mem::size_of::<bindings::shash_desc>()
+            + unsafe { bindings::crypto_shash_descsize(self.shash) } as usize;
+
+        let desc_vec: KVec<u8> = KVec::from_elem(0u8, desc_len, GFP_KERNEL)?;
+        // Consume the desc_vec to make sure it isn't dropped, untill we
+        // manually drop it later
+        let (desc_buf, _length, _capacity) = desc_vec.into_raw_parts();
+
+        // SAFETY: We are casting the allocation to be a shash_desc
+        let desc = unsafe {
+            core::mem::transmute::<*mut c_void, &mut bindings::shash_desc>(desc_buf as *mut c_void)
+        };
+        desc.tfm = self.shash;
+
+        self.desc = Some(desc);
+
+        /* Used frequently to compute offsets, so cache H */
+        self.hash_len = unsafe { bindings::crypto_shash_digestsize(self.shash) as usize };
+
+        if let Some(desc) = &mut self.desc {
+            // SAFETY: `self.desc` is a valid and initalised `shash_desc` sized buffer
+            unsafe { to_result(bindings::crypto_shash_init(*desc)) }
+        } else {
+            Err(ENOMEM)
+        }
+    }
+
+    pub(crate) fn negotiate_algs(&mut self) -> Result<(), Error> {
+        let mut request = NegotiateAlgsReq::default();
+        request.version = self.version;
+
+        if self.version >= SPDM_VER_12 && (self.rsp_caps & SPDM_KEY_EX_CAP) == SPDM_KEY_EX_CAP {
+            request.other_params_support = SPDM_OPAQUE_DATA_FMT_GENERAL;
+        }
+
+        let req_sz = core::mem::size_of::<NegotiateAlgsReq>();
+        let rsp_sz = core::mem::size_of::<NegotiateAlgsRsp>();
+
+        request.length = (req_sz as u16).to_le();
+
+        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
+        let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
+
+        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, rsp_sz, GFP_KERNEL)?;
+
+        let rc = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
+
+        // The transport must report a length within the buffer we provided.
+        if rc > response_vec.len() {
+            pr_err!("Overflowed capabilities response\n");
+            return Err(EIO);
+        }
+        response_vec.truncate(rc);
+
+        let response: &NegotiateAlgsRsp = Untrusted::new(response_vec.as_slice()).validate()?;
+
+        self.base_asym_alg = u32::from_le(response.base_asym_sel);
+        self.base_hash_alg = u32::from_le(response.base_hash_sel);
+        self.meas_hash_alg = u32::from_le(response.measurement_hash_algo);
+
+        if self.base_asym_alg & SPDM_ASYM_ALGOS == 0 || self.base_hash_alg & SPDM_HASH_ALGOS == 0 {
+            pr_err!("No common supported algorithms\n");
+            return Err(EPROTO);
+        }
+
+        // /* Responder shall select exactly 1 alg (SPDM 1.0.0 table 14) */
+        if self.base_asym_alg.count_ones() != 1
+            || self.base_hash_alg.count_ones() != 1
+            || self.meas_hash_alg.count_ones() != 1
+            || response.ext_asym_sel_count != 0
+            || response.ext_hash_sel_count != 0
+            || response.param1 > request.param1
+            || response.other_params_sel != request.other_params_support
+        {
+            pr_err!("Malformed algorithms response\n");
+            return Err(EPROTO);
+        }
+
+        self.update_response_algs()?;
+
+        Ok(())
+    }
 }
diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
index 42c0b28cdcaa..4f7a82d4b210 100644
--- a/lib/rspdm/validator.rs
+++ b/lib/rspdm/validator.rs
@@ -9,7 +9,8 @@
 
 use crate::bindings::{
     __IncompleteArrayField,
-    __le16, //
+    __le16,
+    __le32, //
 };
 use crate::consts::SpdmErrorCode;
 use core::mem;
@@ -26,10 +27,14 @@
 };
 
 use crate::consts::{
+    SPDM_ASYM_ALGOS,
     SPDM_CTEXPONENT,
     SPDM_GET_CAPABILITIES,
     SPDM_GET_VERSION,
+    SPDM_HASH_ALGOS,
+    SPDM_MEAS_SPEC_DMTF,
     SPDM_MIN_VER,
+    SPDM_NEGOTIATE_ALGS,
     SPDM_REQ_CAPS,
     SPDM_VER_10,
     SPDM_VER_11, //
@@ -265,3 +270,106 @@ fn validate(unvalidated: &mut KVec<u8>) -> Result<Self, Self::Err> {
         Ok(rsp)
     }
 }
+
+#[repr(C, packed)]
+pub(crate) struct RegAlg {
+    pub(crate) alg_type: u8,
+    pub(crate) alg_count: u8,
+    pub(crate) alg_supported: u16,
+    pub(crate) alg_external: __IncompleteArrayField<__le32>,
+}
+
+#[repr(C, packed)]
+pub(crate) struct NegotiateAlgsReq {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8, // size of resp_alg_struct
+    param2: u8,
+
+    pub(crate) length: u16,
+    pub(crate) measurement_specification: u8,
+    pub(crate) other_params_support: u8,
+
+    pub(crate) base_asym_algo: u32,
+    pub(crate) base_hash_algo: u32,
+
+    reserved1: [u8; 12],
+
+    pub(crate) ext_asym_count: u8,
+    pub(crate) ext_hash_count: u8,
+    reserved2: u8,
+    pub(crate) mel_specification: u8,
+
+    pub(crate) ext_asym: __IncompleteArrayField<__le32>,
+    pub(crate) ext_hash: __IncompleteArrayField<__le32>,
+    pub(crate) resp_alg_struct: __IncompleteArrayField<RegAlg>,
+}
+
+impl Default for NegotiateAlgsReq {
+    fn default() -> Self {
+        NegotiateAlgsReq {
+            version: 0,
+            code: SPDM_NEGOTIATE_ALGS,
+            param1: 0, // Size of resp_alg_struct
+            param2: 0,
+            length: 32,
+            measurement_specification: SPDM_MEAS_SPEC_DMTF,
+            other_params_support: 0,
+            base_asym_algo: SPDM_ASYM_ALGOS.to_le(),
+            base_hash_algo: SPDM_HASH_ALGOS.to_le(),
+            reserved1: [0u8; 12],
+            ext_asym_count: 0,
+            ext_hash_count: 0,
+            reserved2: 0,
+            mel_specification: 0,
+            ext_asym: __IncompleteArrayField::new(),
+            ext_hash: __IncompleteArrayField::new(),
+            resp_alg_struct: __IncompleteArrayField::new(),
+        }
+    }
+}
+
+#[repr(C, packed)]
+pub(crate) struct NegotiateAlgsRsp {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+
+    pub(crate) length: u16,
+    pub(crate) measurement_specification_sel: u8,
+    pub(crate) other_params_sel: u8,
+
+    pub(crate) measurement_hash_algo: u32,
+    pub(crate) base_asym_sel: u32,
+    pub(crate) base_hash_sel: u32,
+
+    reserved1: [u8; 11],
+
+    pub(crate) mel_specification_sel: u8,
+    pub(crate) ext_asym_sel_count: u8,
+    pub(crate) ext_hash_sel_count: u8,
+    reserved2: [u8; 2],
+
+    pub(crate) ext_asym: __IncompleteArrayField<__le32>,
+    pub(crate) ext_hash: __IncompleteArrayField<__le32>,
+    pub(crate) resp_alg_struct: __IncompleteArrayField<RegAlg>,
+}
+
+impl<'a> Validate<Untrusted<&'a [u8]>> for &'a NegotiateAlgsRsp {
+    type Err = Error;
+
+    fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
+        if unvalidated.len() < mem::size_of::<NegotiateAlgsRsp>() {
+            return Err(EINVAL);
+        }
+
+        let ptr = unvalidated.as_ptr();
+        // CAST: `NegotiateAlgsRsp` only contains integers and has `repr(C)`.
+        let ptr = ptr.cast::<NegotiateAlgsRsp>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        let rsp: &NegotiateAlgsRsp = unsafe { &*ptr };
+
+        Ok(rsp)
+    }
+}
-- 
2.55.0

[PATCH v3 17/21] lib: rspdm: Support SPDM get_digests

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

Support the GET_DIGESTS SPDM command.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 lib/rspdm/consts.rs    |  7 ++--
 lib/rspdm/lib.rs       |  4 +++
 lib/rspdm/state.rs     | 80 +++++++++++++++++++++++++++++++++++++++++-
 lib/rspdm/validator.rs | 53 ++++++++++++++++++++++++++++
 4 files changed, 141 insertions(+), 3 deletions(-)

diff --git a/lib/rspdm/consts.rs b/lib/rspdm/consts.rs
index e222821bad5d..c4d9521866af 100644
--- a/lib/rspdm/consts.rs
+++ b/lib/rspdm/consts.rs
@@ -19,10 +19,11 @@
 pub(crate) const SPDM_VER_10: u8 = 0x10;
 pub(crate) const SPDM_VER_11: u8 = 0x11;
 pub(crate) const SPDM_VER_12: u8 = 0x12;
-#[allow(dead_code)]
 pub(crate) const SPDM_VER_13: u8 = 0x13;
 pub(crate) const SPDM_VER_14: u8 = 0x14;
 
+pub(crate) const SPDM_SLOTS: usize = 8;
+
 pub(crate) const SPDM_MIN_VER: u8 = SPDM_VER_10;
 pub(crate) const SPDM_MAX_VER: u8 = SPDM_VER_14;
 
@@ -106,7 +107,7 @@ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
     mem::size_of::<GetVersionRsp>() + (u8::MAX as usize) * mem::size_of::<u16>();
 
 pub(crate) const SPDM_GET_CAPABILITIES: u8 = 0xe1;
-pub(crate) const SPDM_MIN_DATA_TRANSFER_SIZE: u32 = 42;
+pub(crate) const SPDM_MIN_DATA_TRANSFER_SIZE: u32 = 42; // SPDM 1.2.0 margin no 226
 
 // SPDM cryptographic timeout of this implementation:
 // Assume calculations may take up to 1 sec on a busy machine, which equals
@@ -143,6 +144,8 @@ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 pub(crate) const SPDM_HASH_SHA_384: u32 = bit_u32(1);
 pub(crate) const SPDM_HASH_SHA_512: u32 = bit_u32(2);
 
+pub(crate) const SPDM_GET_DIGESTS: u8 = 0x81;
+
 // If the crypto support isn't enabled don't offer the algorithms
 // to the responder
 #[cfg(CONFIG_CRYPTO_RSA)]
diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
index d418d15e4c70..bda5f91ca13c 100644
--- a/lib/rspdm/lib.rs
+++ b/lib/rspdm/lib.rs
@@ -110,6 +110,10 @@ pub extern "C" fn spdm_authenticate(state_ptr: *mut spdm_state) -> c_int {
         return e.to_errno() as c_int;
     }
 
+    if let Err(e) = state.get_digests() {
+        return e.to_errno() as c_int;
+    }
+
     -(EPROTONOSUPPORT as i32)
 }
 
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
index b78086c75370..131c22319b26 100644
--- a/lib/rspdm/state.rs
+++ b/lib/rspdm/state.rs
@@ -44,13 +44,17 @@
     SPDM_OPAQUE_DATA_FMT_GENERAL,
     SPDM_REQ,
     SPDM_RSP_MIN_CAPS,
+    SPDM_SLOTS,
     SPDM_VER_10,
     SPDM_VER_11,
-    SPDM_VER_12, //
+    SPDM_VER_12,
+    SPDM_VER_13, //
 };
 use crate::validator::{
     GetCapabilitiesReq,
     GetCapabilitiesRsp,
+    GetDigestsReq,
+    GetDigestsRsp,
     GetVersionReq,
     GetVersionRsp,
     NegotiateAlgsReq,
@@ -86,6 +90,10 @@
 ///  Selected by responder during NEGOTIATE_ALGORITHMS exchange.
 /// @meas_hash_alg: Hash algorithm for measurement blocks.
 ///  Selected by responder during NEGOTIATE_ALGORITHMS exchange.
+/// @supported_slots: Bitmask of responder's supported certificate slots.
+///  Received during GET_DIGESTS exchange (from SPDM 1.3).
+/// @provisioned_slots: Bitmask of responder's provisioned certificate slots.
+///  Received during GET_DIGESTS exchange.
 /// @base_asym_enc: Human-readable name of @base_asym_alg's signature encoding.
 ///  Passed to crypto subsystem when calling verify_signature().
 /// @sig_len: Signature length of @base_asym_alg (in bytes).
@@ -97,6 +105,8 @@
 /// @desc: Synchronous hash context for @base_hash_alg computation.
 /// @hash_len: Hash length of @base_hash_alg (in bytes).
 ///  H in SPDM specification.
+/// @certs: Certificate chain in each of the 8 slots. Empty KVec if a slot is
+///  not populated. Prefixed by the 4 + H header per SPDM 1.0.0 table 15.
 #[expect(dead_code)]
 pub(crate) struct SpdmState<'a> {
     pub(crate) dev: *mut bindings::device,
@@ -111,6 +121,8 @@ pub(crate) struct SpdmState<'a> {
     pub(crate) base_asym_alg: u32,
     pub(crate) base_hash_alg: u32,
     pub(crate) meas_hash_alg: u32,
+    pub(crate) supported_slots: u8,
+    pub(crate) provisioned_slots: u8,
 
     /* Signature algorithm */
     base_asym_enc: &'a CStr,
@@ -121,6 +133,9 @@ pub(crate) struct SpdmState<'a> {
     pub(crate) shash: *mut bindings::crypto_shash,
     pub(crate) desc: Option<&'a mut bindings::shash_desc>,
     pub(crate) hash_len: usize,
+
+    // Certificates
+    pub(crate) certs: [KVec<u8>; SPDM_SLOTS],
 }
 
 impl Drop for SpdmState<'_> {
@@ -163,12 +178,15 @@ pub(crate) fn new(
             base_asym_alg: 0,
             base_hash_alg: 0,
             meas_hash_alg: 0,
+            supported_slots: 0,
+            provisioned_slots: 0,
             base_asym_enc: unsafe { CStr::from_bytes_with_nul_unchecked(b"\0") },
             sig_len: 0,
             base_hash_alg_name: unsafe { CStr::from_bytes_with_nul_unchecked(b"\0") },
             shash: core::ptr::null_mut(),
             desc: None,
             hash_len: 0,
+            certs: [const { KVec::new() }; SPDM_SLOTS],
         }
     }
 
@@ -612,4 +630,64 @@ pub(crate) fn negotiate_algs(&mut self) -> Result<(), Error> {
 
         Ok(())
     }
+
+    pub(crate) fn get_digests(&mut self) -> Result<(), Error> {
+        let mut request = GetDigestsReq::default();
+        request.version = self.version;
+
+        let req_sz = core::mem::size_of::<GetDigestsReq>();
+        let rsp_sz = core::mem::size_of::<GetDigestsRsp>() + SPDM_SLOTS * self.hash_len;
+
+        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
+        let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
+
+        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, rsp_sz, GFP_KERNEL)?;
+
+        let len = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
+
+        // The transport must report a length within the buffer we provided.
+        if len > response_vec.len() {
+            pr_err!("Overflowed digests response\n");
+            return Err(EIO);
+        }
+        response_vec.truncate(len);
+
+        let response: &GetDigestsRsp = Untrusted::new(response_vec.as_slice()).validate()?;
+
+        if len
+            < core::mem::size_of::<GetDigestsRsp>()
+                + response.param2.count_ones() as usize * self.hash_len
+        {
+            pr_err!("Overflowed digests response\n");
+            return Err(EIO);
+        }
+
+        let mut deprovisioned_slots = self.provisioned_slots & !response.param2;
+        while (deprovisioned_slots.trailing_zeros() as usize) < SPDM_SLOTS {
+            let slot = deprovisioned_slots.trailing_zeros() as usize;
+            self.certs[slot].clear();
+            deprovisioned_slots &= !(1 << slot);
+        }
+
+        if self.version >= SPDM_VER_13 && (response.param2 & !response.param1 != 0) {
+            pr_err!("Malformed digests response\n");
+            return Err(EPROTO);
+        }
+
+        self.provisioned_slots = response.param2;
+        if self.provisioned_slots == 0 {
+            pr_err!("No certificates provisioned\n");
+            return Err(EPROTO);
+        }
+
+        let supported_slots = if self.version >= SPDM_VER_13 {
+            response.param1
+        } else {
+            0xFF
+        };
+
+        self.supported_slots = supported_slots;
+
+        Ok(())
+    }
 }
diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
index 4f7a82d4b210..ddbf5c448bd7 100644
--- a/lib/rspdm/validator.rs
+++ b/lib/rspdm/validator.rs
@@ -30,6 +30,7 @@
     SPDM_ASYM_ALGOS,
     SPDM_CTEXPONENT,
     SPDM_GET_CAPABILITIES,
+    SPDM_GET_DIGESTS,
     SPDM_GET_VERSION,
     SPDM_HASH_ALGOS,
     SPDM_MEAS_SPEC_DMTF,
@@ -373,3 +374,55 @@ fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
         Ok(rsp)
     }
 }
+
+#[repr(C, packed)]
+pub(crate) struct GetDigestsReq {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+}
+
+impl Default for GetDigestsReq {
+    fn default() -> Self {
+        GetDigestsReq {
+            version: 0,
+            code: SPDM_GET_DIGESTS,
+            param1: 0,
+            param2: 0,
+        }
+    }
+}
+
+#[repr(C, packed)]
+pub(crate) struct GetDigestsRsp {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+
+    pub(crate) digests: __IncompleteArrayField<u8>,
+    // KeyPairIDs, added in 1.3
+
+    // CertificateInfo, added in 1.3
+
+    // KeyUsageMask, added in 1.3
+}
+
+impl<'a> Validate<Untrusted<&'a [u8]>> for &'a GetDigestsRsp {
+    type Err = Error;
+
+    fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
+        if unvalidated.len() < mem::size_of::<GetDigestsRsp>() {
+            return Err(EINVAL);
+        }
+
+        let ptr = unvalidated.as_ptr();
+        // CAST: `GetDigestsRsp` only contains integers and has `repr(C)`.
+        let ptr = ptr.cast::<GetDigestsRsp>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        let rsp: &GetDigestsRsp = unsafe { &*ptr };
+
+        Ok(rsp)
+    }
+}
-- 
2.55.0

[PATCH v3 18/21] lib: rspdm: Support SPDM get_certificate

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

Support the GET_CERTIFICATE SPDM command.

The kernel will send a GET_CERTIFICATE request to the the responder and
then iterate over all of the certificates returned.

Certificate validation happens in the next commit.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 lib/rspdm/consts.rs    |   2 +
 lib/rspdm/lib.rs       |  15 ++++
 lib/rspdm/state.rs     | 156 +++++++++++++++++++++++++++++++++++++++++
 lib/rspdm/validator.rs |  65 +++++++++++++++++
 4 files changed, 238 insertions(+)

diff --git a/lib/rspdm/consts.rs b/lib/rspdm/consts.rs
index c4d9521866af..2fbc4ab41869 100644
--- a/lib/rspdm/consts.rs
+++ b/lib/rspdm/consts.rs
@@ -146,6 +146,8 @@ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 
 pub(crate) const SPDM_GET_DIGESTS: u8 = 0x81;
 
+pub(crate) const SPDM_GET_CERTIFICATE: u8 = 0x82;
+
 // If the crypto support isn't enabled don't offer the algorithms
 // to the responder
 #[cfg(CONFIG_CRYPTO_RSA)]
diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
index bda5f91ca13c..488203be821d 100644
--- a/lib/rspdm/lib.rs
+++ b/lib/rspdm/lib.rs
@@ -114,6 +114,21 @@ pub extern "C" fn spdm_authenticate(state_ptr: *mut spdm_state) -> c_int {
         return e.to_errno() as c_int;
     }
 
+    if state.provisioned_slots == 0 {
+        return -(bindings::EIO as c_int);
+    }
+
+    let mut provisioned_slots = state.provisioned_slots;
+    while (provisioned_slots as usize) > 0 {
+        let slot = provisioned_slots.trailing_zeros() as u8;
+
+        if let Err(e) = state.get_certificate(slot) {
+            return e.to_errno() as c_int;
+        }
+
+        provisioned_slots &= !(1 << slot);
+    }
+
     -(EPROTONOSUPPORT as i32)
 }
 
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
index 131c22319b26..1e8a4402e634 100644
--- a/lib/rspdm/state.rs
+++ b/lib/rspdm/state.rs
@@ -53,6 +53,8 @@
 use crate::validator::{
     GetCapabilitiesReq,
     GetCapabilitiesRsp,
+    GetCertificateReq,
+    GetCertificateRsp,
     GetDigestsReq,
     GetDigestsRsp,
     GetVersionReq,
@@ -159,6 +161,17 @@ fn drop(&mut self) {
     }
 }
 
+#[repr(C, packed)]
+pub(crate) struct SpdmCertChain {
+    // `length` is a u16 (with 2 bytes reserved) for SPDM versions 1.3
+    // and lower and u32 for 1.4. We don't currently support `LargeOffset`
+    // and `LargeLength`, so let's pretend this is always a u16
+    length: u16,
+    _reserved: [u8; 2],
+    root_hash: bindings::__IncompleteArrayField<u8>,
+    certificates: bindings::__IncompleteArrayField<u8>,
+}
+
 impl SpdmState<'_> {
     pub(crate) fn new(
         dev: *mut bindings::device,
@@ -690,4 +703,147 @@ pub(crate) fn get_digests(&mut self) -> Result<(), Error> {
 
         Ok(())
     }
+
+    fn get_cert_exchange<'a>(
+        &mut self,
+        request_buf: &mut [u8],
+        response_vec: &'a mut KVec<u8>,
+    ) -> Result<&'a GetCertificateRsp, Error> {
+        let len = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
+
+        // The transport must report a length within the buffer we provided.
+        if len < core::mem::size_of::<GetCertificateRsp>() {
+            pr_err!("Truncated certificate response\n");
+            return Err(EIO);
+        }
+        if len > response_vec.len() {
+            pr_err!("Overflowed get certificate response\n");
+            return Err(EIO);
+        }
+        response_vec.truncate(len);
+
+        let response: &GetCertificateRsp = Untrusted::new(response_vec.as_slice()).validate()?;
+
+        if len
+            < core::mem::size_of::<GetCertificateRsp>()
+                + u16::from_le(response.portion_length) as usize
+        {
+            pr_err!("Truncated certificate response\n");
+            return Err(EIO);
+        }
+
+        Ok(response)
+    }
+
+    pub(crate) fn get_certificate(&mut self, slot: u8) -> Result<(), Error> {
+        let mut request = GetCertificateReq::default();
+        request.version = self.version;
+        request.param1 = slot;
+
+        let req_sz = core::mem::size_of::<GetCertificateReq>();
+        let rsp_sz = (core::mem::size_of::<GetCertificateRsp>() as u32 + u16::MAX as u32)
+            .min(self.transport_sz) as usize;
+
+        request.offset = 0;
+        request.length = ((rsp_sz - core::mem::size_of::<GetCertificateRsp>()) as u16).to_le();
+
+        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
+        let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
+
+        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, rsp_sz, GFP_KERNEL)?;
+
+        let response = self.get_cert_exchange(request_buf, &mut response_vec)?;
+
+        if response.param1 != slot {
+            pr_err!("Invalid slot response\n");
+            return Err(EPROTO);
+        }
+
+        let portion_length = response.portion_length;
+        let rem_length = response.remainder_length;
+
+        let total_cert_len = u16::from_le(portion_length) as usize
+            + u16::from_le(response.remainder_length) as usize;
+
+        let mut certs_buf: KVec<u8> = KVec::new();
+
+        certs_buf.extend_from_slice(
+            &response_vec[8..(8 + u16::from_le(portion_length) as usize)],
+            GFP_KERNEL,
+        )?;
+
+        let mut offset: u16 = u16::from_le(portion_length);
+        let mut remainder_length = u16::from_le(rem_length) as usize;
+
+        while remainder_length > 0 {
+            request.offset = offset.to_le();
+            request.length =
+                ((remainder_length.min(rsp_sz - core::mem::size_of::<GetCertificateRsp>())) as u16)
+                    .to_le();
+
+            let request_buf =
+                unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
+
+            response_vec.resize(
+                request.length as usize + core::mem::size_of::<GetCertificateRsp>(),
+                0,
+                GFP_KERNEL,
+            )?;
+
+            let response = self.get_cert_exchange(request_buf, &mut response_vec)?;
+
+            let portion_length = response.portion_length;
+            let rem_length = response.remainder_length;
+
+            if u16::from_le(portion_length) == 0
+                || (response.param1 & 0xF) != slot
+                || offset as usize
+                    + u16::from_le(portion_length) as usize
+                    + u16::from_le(rem_length) as usize
+                    != total_cert_len
+            {
+                pr_err!("Malformed certificate response\n");
+                return Err(EPROTO);
+            }
+
+            certs_buf.extend_from_slice(
+                &response_vec[8..(8 + u16::from_le(portion_length) as usize)],
+                GFP_KERNEL,
+            )?;
+            let (val, overflow) = offset.overflowing_add(u16::from_le(portion_length));
+            if overflow {
+                pr_err!("portion_length  response overflowed\n");
+                return Err(EPROTO);
+            }
+            offset = val;
+            remainder_length = u16::from_le(rem_length) as usize;
+        }
+
+        let header_length = core::mem::size_of::<SpdmCertChain>() + self.hash_len;
+
+        if total_cert_len < header_length as usize || total_cert_len != certs_buf.len() {
+            pr_err!("Malformed certificate chain in slot {slot}\n");
+            return Err(EPROTO);
+        }
+
+        let cert_chain_length = {
+            let ptr = certs_buf.as_ptr();
+            // SAFETY: `SpdmCertChain` is repr(C) and packed. We just
+            // checked the length above so we can convert it from a slice
+            let ptr = ptr.cast::<SpdmCertChain>();
+            // SAFETY: `ptr` came from a reference and the cast above is valid.
+            let certs: &SpdmCertChain = unsafe { &*ptr };
+            u16::from_le(certs.length) as usize
+        };
+
+        if total_cert_len != cert_chain_length {
+            pr_err!("Malformed certificate chain in slot {slot}\n");
+            return Err(EPROTO);
+        }
+
+        self.certs[slot as usize].clear();
+        self.certs[slot as usize].extend_from_slice(&certs_buf, GFP_KERNEL)?;
+
+        Ok(())
+    }
 }
diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
index ddbf5c448bd7..2584bed73979 100644
--- a/lib/rspdm/validator.rs
+++ b/lib/rspdm/validator.rs
@@ -30,6 +30,7 @@
     SPDM_ASYM_ALGOS,
     SPDM_CTEXPONENT,
     SPDM_GET_CAPABILITIES,
+    SPDM_GET_CERTIFICATE,
     SPDM_GET_DIGESTS,
     SPDM_GET_VERSION,
     SPDM_HASH_ALGOS,
@@ -426,3 +427,67 @@ fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
         Ok(rsp)
     }
 }
+
+#[repr(C, packed)]
+pub(crate) struct GetCertificateReq {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+
+    pub(crate) offset: u16,
+    pub(crate) length: u16,
+}
+
+impl Default for GetCertificateReq {
+    fn default() -> Self {
+        GetCertificateReq {
+            version: 0,
+            code: SPDM_GET_CERTIFICATE,
+            param1: 0,
+            param2: 0,
+            offset: 0,
+            length: 0,
+        }
+    }
+}
+
+#[repr(C, packed)]
+pub(crate) struct GetCertificateRsp {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+
+    pub(crate) portion_length: u16,
+    pub(crate) remainder_length: u16,
+
+    pub(crate) cert_chain: __IncompleteArrayField<u8>,
+}
+
+impl<'a> Validate<Untrusted<&'a [u8]>> for &'a GetCertificateRsp {
+    type Err = Error;
+
+    fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
+        if unvalidated.len() < mem::size_of::<GetCertificateRsp>() {
+            return Err(EINVAL);
+        }
+
+        let rsp_sz = core::mem::size_of::<SpdmHeader>()
+            + 4
+            + (*(unvalidated.get(4).ok_or(EINVAL))? as usize)
+            + ((*(unvalidated.get(5).ok_or(EINVAL))? as usize) << 8);
+
+        if unvalidated.len() < rsp_sz {
+            return Err(EINVAL);
+        }
+
+        let ptr = unvalidated.as_ptr();
+        // CAST: `GetCertificateRsp` only contains integers and has `repr(C)`.
+        let ptr = ptr.cast::<GetCertificateRsp>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        let rsp: &GetCertificateRsp = unsafe { &*ptr };
+
+        Ok(rsp)
+    }
+}
-- 
2.55.0

[PATCH v3 19/21] lib: rspdm: Support SPDM certificate validation

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

Support validating the SPDM certificate chain. This only performs basic
sanity checks on the chain before we continue on. This does not ensure
that the root CA is trusted, we leave that for userspace to check and
enforce. Instead we just make sure that the chain is correct, uses
supported signatures and that it isn't blacklisted in the kernel.

We then store the first leaf certificate for use later.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 lib/rspdm/lib.rs                |  12 +++
 lib/rspdm/state.rs              | 146 +++++++++++++++++++++++++++++++-
 rust/bindings/bindings_helper.h |   2 +
 3 files changed, 159 insertions(+), 1 deletion(-)

diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
index 488203be821d..fa5513e8bd4e 100644
--- a/lib/rspdm/lib.rs
+++ b/lib/rspdm/lib.rs
@@ -129,6 +129,18 @@ pub extern "C" fn spdm_authenticate(state_ptr: *mut spdm_state) -> c_int {
         provisioned_slots &= !(1 << slot);
     }
 
+    let mut provisioned_slots = state.provisioned_slots;
+    while (provisioned_slots as usize) > 0 {
+        let slot = provisioned_slots.trailing_zeros() as u8;
+
+        if let Err(e) = state.validate_cert_chain(slot) {
+            pr_err!("Certificate in slot {slot} failed to verify: {e:?}\n");
+            return e.to_errno() as c_int;
+        }
+
+        provisioned_slots &= !(1 << slot);
+    }
+
     -(EPROTONOSUPPORT as i32)
 }
 
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
index 1e8a4402e634..fc7df9dd7b97 100644
--- a/lib/rspdm/state.rs
+++ b/lib/rspdm/state.rs
@@ -109,7 +109,8 @@
 ///  H in SPDM specification.
 /// @certs: Certificate chain in each of the 8 slots. Empty KVec if a slot is
 ///  not populated. Prefixed by the 4 + H header per SPDM 1.0.0 table 15.
-#[expect(dead_code)]
+/// @leaf_key: Public key portion of leaf certificate against which to check
+///  responder's signatures.
 pub(crate) struct SpdmState<'a> {
     pub(crate) dev: *mut bindings::device,
     pub(crate) transport: bindings::spdm_transport,
@@ -138,10 +139,20 @@ pub(crate) struct SpdmState<'a> {
 
     // Certificates
     pub(crate) certs: [KVec<u8>; SPDM_SLOTS],
+    pub(crate) leaf_key: Option<*mut bindings::public_key>,
 }
 
 impl Drop for SpdmState<'_> {
     fn drop(&mut self) {
+        if let Some(leaf_key) = self.leaf_key.take() {
+            // SAFETY: `leaf_key` was extracted from a x509 certificate
+            // in `validate_cert_chain()` so it is valid to pass to
+            // `public_key_free()`.
+            unsafe {
+                bindings::public_key_free(leaf_key);
+            }
+        }
+
         if let Some(desc) = self.desc.take() {
             // SAFETY: `self.shash` is a valid handle
             let desc_len = core::mem::size_of::<bindings::shash_desc>()
@@ -200,6 +211,7 @@ pub(crate) fn new(
             desc: None,
             hash_len: 0,
             certs: [const { KVec::new() }; SPDM_SLOTS],
+            leaf_key: None,
         }
     }
 
@@ -846,4 +858,136 @@ pub(crate) fn get_certificate(&mut self, slot: u8) -> Result<(), Error> {
 
         Ok(())
     }
+
+    pub(crate) fn validate_cert_chain(&mut self, slot: u8) -> Result<(), Error> {
+        let cert_chain_buf = &self.certs[slot as usize];
+        let cert_chain_len = cert_chain_buf.len();
+        // We skip over the RootHash
+        let header_len = 4 + self.hash_len;
+
+        let mut offset = header_len;
+        let mut prev_cert: Option<*mut bindings::x509_certificate> = None;
+
+        if offset >= cert_chain_len {
+            return Err(EPROTO);
+        }
+
+        while offset < cert_chain_len {
+            // SAFETY: `cert_chain_buf[offset..]` is a non-empty slice of
+            // bytes valid for at least `cert_chain_len` bytes.
+            let cert_len = unsafe {
+                bindings::x509_get_certificate_length(
+                    &cert_chain_buf[offset..] as *const _ as *const u8,
+                    cert_chain_len - offset,
+                )
+            };
+
+            if cert_len < 0 {
+                pr_err!("Invalid certificate length\n");
+
+                if let Some(prev) = prev_cert {
+                    // SAFETY: `prev_cert` is the previously parsed
+                    // certificate from a prior loop iteration.
+                    unsafe { bindings::x509_free_certificate(prev) };
+                }
+
+                to_result(cert_len as i32)?;
+            }
+
+            // SAFETY: `cert_chain_buf[offset..]` is a non-empty slice of
+            // bytes valid for at least `cert_len` bytes.
+            let cert_ptr = unsafe {
+                match from_err_ptr(bindings::x509_cert_parse(
+                    &cert_chain_buf[offset..] as *const _ as *const c_void,
+                    cert_len as usize,
+                )) {
+                    Err(e) => {
+                        if let Some(prev) = prev_cert {
+                            // SAFETY: `prev_cert` is the previously parsed
+                            // certificate from a prior loop iteration.
+                            bindings::x509_free_certificate(prev);
+                        }
+                        return Err(e);
+                    }
+                    Ok(c) => c,
+                }
+            };
+            // SAFETY: Cast the `struct x509_certificate` to a Rust binding
+            let cert = unsafe { *cert_ptr };
+
+            if cert.unsupported_sig || cert.blacklisted {
+                pr_err!("Certificate was rejected\n");
+
+                if let Some(prev) = prev_cert {
+                    // SAFETY: `prev_cert` is the previously parsed
+                    // certificate from a prior loop iteration.
+                    unsafe { bindings::x509_free_certificate(prev) };
+                }
+                // SAFETY: `cert_ptr` was just returned by
+                // `x509_cert_parse()`.
+                unsafe { bindings::x509_free_certificate(cert_ptr) };
+
+                return Err(EKEYREJECTED);
+            }
+
+            if let Some(prev) = prev_cert {
+                // SAFETY: `prev_cert` is the previously parsed
+                // certificate from a prior loop iteration.
+                let rc = unsafe { bindings::public_key_verify_signature((*prev).pub_, cert.sig) };
+
+                if rc < 0 {
+                    pr_err!("Signature validation error\n");
+
+                    // SAFETY: `prev_cert` is the previously parsed
+                    // certificate from a prior loop iteration.
+                    unsafe { bindings::x509_free_certificate(prev) };
+
+                    // SAFETY: `cert_ptr` was just returned by
+                    // `x509_cert_parse()`.
+                    unsafe { bindings::x509_free_certificate(cert_ptr) };
+
+                    to_result(rc)?;
+                }
+            }
+
+            if let Some(prev) = prev_cert {
+                // SAFETY: `prev_cert` is the previously parsed
+                // certificate from a prior loop iteration.
+                unsafe { bindings::x509_free_certificate(prev) };
+            }
+
+            prev_cert = Some(cert_ptr);
+            offset += cert_len as usize;
+        }
+
+        if let Some(prev) = prev_cert {
+            if let Some(validate) = self.validate {
+                // SAFETY: Call the `validate` function provided.
+                let rc = unsafe { validate(self.dev, slot, prev) };
+                if let Err(e) = to_result(rc) {
+                    // SAFETY: `prev_cert` is the previously parsed
+                    // certificate from a prior loop iteration.
+                    unsafe { bindings::x509_free_certificate(prev) };
+                    return Err(e);
+                }
+            }
+
+            // The leaf key is the same for all slots, so just store the first one.
+            if self.leaf_key.is_none() {
+                // SAFETY: `prev_cert` is the previously parsed
+                // certificate from a prior loop iteration.
+                self.leaf_key = unsafe { Some((*prev).pub_) };
+                // SAFETY: `prev_cert` is the previously parsed
+                // certificate from a prior loop iteration. We are setting
+                // the `pub` key to null so it isn't freed below
+                unsafe { (*prev).pub_ = core::ptr::null_mut() };
+            }
+
+            // SAFETY: `prev_cert` is the previously parsed
+            // certificate from a prior loop iteration.
+            unsafe { bindings::x509_free_certificate(prev) };
+        }
+
+        Ok(())
+    }
 }
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index d2781c27794b..5cc71552b524 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -38,6 +38,8 @@
 #include <drm/drm_gem_shmem_helper.h>
 #include <drm/drm_gpuvm.h>
 #include <drm/drm_ioctl.h>
+#include <keys/asymmetric-type.h>
+#include <keys/x509-parser.h>
 #include <kunit/test.h>
 #include <linux/auxiliary_bus.h>
 #include <linux/bitmap.h>
-- 
2.55.0

[PATCH v3 20/21] rust: allow extracting the buffer from a CString

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

The kernel CString is a wrapper around a KVec. This patch allows
retrieving the underlying buffer and consuming the CString. This allows
users to create a CString from a string and then retrieve the underlying
buffer.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
---
 rust/kernel/str.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index a556788bcc5e..3fd8a218547f 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -870,6 +870,12 @@ pub fn try_from_fmt(args: fmt::Arguments<'_>) -> Result<Self, Error> {
         // exist in the buffer.
         Ok(Self { buf })
     }
+
+    /// Return the internal buffer while consuming the original [`CString`]
+    #[inline]
+    pub fn into_vec(self) -> KVec<u8> {
+        self.buf
+    }
 }
 
 impl Deref for CString {
-- 
2.55.0

[PATCH v3 21/21] lib: rspdm: Support SPDM challenge

[alistair23]

From: Alistair Francis <alistair@alistair23.me>

Support the CHALLENGE SPDM command.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
---
 lib/rspdm/consts.rs             |   6 +
 lib/rspdm/lib.rs                |  10 +-
 lib/rspdm/state.rs              | 239 +++++++++++++++++++++++++++++++-
 lib/rspdm/validator.rs          |  61 ++++++++
 rust/bindings/bindings_helper.h |   1 +
 5 files changed, 313 insertions(+), 4 deletions(-)

diff --git a/lib/rspdm/consts.rs b/lib/rspdm/consts.rs
index 2fbc4ab41869..e67be8e6b057 100644
--- a/lib/rspdm/consts.rs
+++ b/lib/rspdm/consts.rs
@@ -148,6 +148,8 @@ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 
 pub(crate) const SPDM_GET_CERTIFICATE: u8 = 0x82;
 
+pub(crate) const SPDM_CHALLENGE: u8 = 0x83;
+
 // If the crypto support isn't enabled don't offer the algorithms
 // to the responder
 #[cfg(CONFIG_CRYPTO_RSA)]
@@ -176,3 +178,7 @@ fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 pub(crate) const SPDM_HASH_ALGOS: u32 = SPDM_HASH_SHA2_256 | SPDM_HASH_SHA2_384_512;
 
 pub(crate) const SPDM_OPAQUE_DATA_FMT_GENERAL: u8 = bit_u8(1);
+
+pub(crate) const SPDM_PREFIX_SZ: usize = 64;
+pub(crate) const SPDM_COMBINED_PREFIX_SZ: usize = 100;
+pub(crate) const SPDM_MAX_OPAQUE_DATA: usize = 1024;
diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
index fa5513e8bd4e..33c16f7ffb46 100644
--- a/lib/rspdm/lib.rs
+++ b/lib/rspdm/lib.rs
@@ -11,8 +11,7 @@
 //! from other subsytems.
 
 use crate::bindings::{
-    spdm_state,
-    EPROTONOSUPPORT, //
+    spdm_state, //
 };
 use core::ffi::{
     c_int,
@@ -141,7 +140,12 @@ pub extern "C" fn spdm_authenticate(state_ptr: *mut spdm_state) -> c_int {
         provisioned_slots &= !(1 << slot);
     }
 
-    -(EPROTONOSUPPORT as i32)
+    let provisioned_slots = state.provisioned_slots.trailing_zeros();
+    if let Err(e) = state.challenge(provisioned_slots as u8) {
+        return e.to_errno() as c_int;
+    }
+
+    0
 }
 
 /// spdm_destroy() - Destroy SPDM session
diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
index fc7df9dd7b97..1fd691037fa5 100644
--- a/lib/rspdm/state.rs
+++ b/lib/rspdm/state.rs
@@ -8,6 +8,7 @@
 //! <https://www.dmtf.org/dsp/DSP0274>
 
 use core::ffi::c_void;
+use core::mem::offset_of;
 use core::slice::from_raw_parts_mut;
 use kernel::prelude::*;
 use kernel::{
@@ -19,6 +20,7 @@
         Error, //
     },
     str::CStr,
+    str::CString,
     validate::Untrusted,
 };
 
@@ -31,6 +33,7 @@
     SPDM_ASYM_RSASSA_2048,
     SPDM_ASYM_RSASSA_3072,
     SPDM_ASYM_RSASSA_4096,
+    SPDM_COMBINED_PREFIX_SZ,
     SPDM_ERROR,
     SPDM_GET_VERSION_LEN,
     SPDM_HASH_ALGOS,
@@ -38,10 +41,12 @@
     SPDM_HASH_SHA_384,
     SPDM_HASH_SHA_512,
     SPDM_KEY_EX_CAP,
+    SPDM_MAX_OPAQUE_DATA,
     SPDM_MAX_VER,
     SPDM_MIN_DATA_TRANSFER_SIZE,
     SPDM_MIN_VER,
     SPDM_OPAQUE_DATA_FMT_GENERAL,
+    SPDM_PREFIX_SZ,
     SPDM_REQ,
     SPDM_RSP_MIN_CAPS,
     SPDM_SLOTS,
@@ -51,6 +56,8 @@
     SPDM_VER_13, //
 };
 use crate::validator::{
+    ChallengeReq,
+    ChallengeRsp,
     GetCapabilitiesReq,
     GetCapabilitiesRsp,
     GetCertificateReq,
@@ -65,6 +72,8 @@
     SpdmHeader, //
 };
 
+const SPDM_CONTEXT: &str = "responder-challenge_auth signing";
+
 /// The current SPDM session state for a device. Based on the
 /// C `struct spdm_state`.
 ///
@@ -111,6 +120,12 @@
 ///  not populated. Prefixed by the 4 + H header per SPDM 1.0.0 table 15.
 /// @leaf_key: Public key portion of leaf certificate against which to check
 ///  responder's signatures.
+/// @transcript: Concatenation of all SPDM messages exchanged during an
+///  authentication or measurement sequence.  Used to verify the signature,
+///  as it is computed over the hashed transcript.
+/// @next_nonce: Requester nonce to be used for the next authentication
+///  sequence.  Populated from user space through sysfs.
+///  If user space does not provide a nonce, the kernel uses a random one.
 pub(crate) struct SpdmState<'a> {
     pub(crate) dev: *mut bindings::device,
     pub(crate) transport: bindings::spdm_transport,
@@ -140,6 +155,10 @@ pub(crate) struct SpdmState<'a> {
     // Certificates
     pub(crate) certs: [KVec<u8>; SPDM_SLOTS],
     pub(crate) leaf_key: Option<*mut bindings::public_key>,
+
+    transcript: VVec<u8>,
+
+    pub(crate) next_nonce: KVec<u8>,
 }
 
 impl Drop for SpdmState<'_> {
@@ -212,6 +231,8 @@ pub(crate) fn new(
             hash_len: 0,
             certs: [const { KVec::new() }; SPDM_SLOTS],
             leaf_key: None,
+            transcript: VVec::new(),
+            next_nonce: KVec::new(),
         }
     }
 
@@ -327,13 +348,15 @@ fn spdm_err(&self, rsp: &SpdmErrorRsp) -> Result<(), Error> {
     /// The data in `request_buf` is sent to the device and the response is
     /// stored in `response_buf`.
     pub(crate) fn spdm_exchange(
-        &self,
+        &mut self,
         request_buf: &mut [u8],
         response_buf: &mut [u8],
     ) -> Result<i32, Error> {
         let header_size = core::mem::size_of::<SpdmHeader>();
         let request: &SpdmHeader = Untrusted::new(&request_buf[..]).validate()?;
 
+        self.transcript.extend_from_slice(request_buf, GFP_KERNEL)?;
+
         let transport_function = self.transport.ok_or(EINVAL)?;
         // SAFETY: `transport_function` is provided by the new(), we are
         // calling the function.
@@ -383,6 +406,8 @@ pub(crate) fn get_version(&mut self) -> Result<(), Error> {
         request.version = SPDM_MIN_VER;
         self.version = SPDM_MIN_VER;
 
+        self.transcript.clear();
+
         // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
         let request_buf = unsafe {
             from_raw_parts_mut(
@@ -402,6 +427,16 @@ pub(crate) fn get_version(&mut self) -> Result<(), Error> {
         response_vec.truncate(rc);
 
         let response: &GetVersionRsp = Untrusted::new(response_vec.as_slice()).validate()?;
+        let rsp_sz = core::mem::size_of::<SpdmHeader>()
+            + 2
+            + response.version_number_entry_count as usize * 2;
+
+        if rsp_sz > response_vec.len() {
+            return Err(EIO);
+        }
+
+        self.transcript
+            .extend_from_slice(&response_vec[..rsp_sz], GFP_KERNEL)?;
 
         let mut foundver = false;
         let entry_count = response.version_number_entry_count;
@@ -471,6 +506,13 @@ pub(crate) fn get_capabilities(&mut self) -> Result<(), Error> {
         }
         response_vec.truncate(rc);
 
+        if rsp_sz > response_vec.len() {
+            return Err(EIO);
+        }
+
+        self.transcript
+            .extend_from_slice(&response_vec[..rsp_sz], GFP_KERNEL)?;
+
         let response: &mut GetCapabilitiesRsp = Untrusted::new(&mut response_vec).validate()?;
 
         self.rsp_caps = u32::from_le(response.flags);
@@ -629,6 +671,9 @@ pub(crate) fn negotiate_algs(&mut self) -> Result<(), Error> {
 
         let response: &NegotiateAlgsRsp = Untrusted::new(response_vec.as_slice()).validate()?;
 
+        self.transcript
+            .extend_from_slice(&response_vec, GFP_KERNEL)?;
+
         self.base_asym_alg = u32::from_le(response.base_asym_sel);
         self.base_hash_alg = u32::from_le(response.base_hash_sel);
         self.meas_hash_alg = u32::from_le(response.measurement_hash_algo);
@@ -678,6 +723,14 @@ pub(crate) fn get_digests(&mut self) -> Result<(), Error> {
         response_vec.truncate(len);
 
         let response: &GetDigestsRsp = Untrusted::new(response_vec.as_slice()).validate()?;
+        let rsp_sz = core::mem::size_of::<SpdmHeader>() + response.param2 as usize * self.hash_len;
+
+        if rsp_sz > response_vec.len() {
+            return Err(EIO);
+        }
+
+        self.transcript
+            .extend_from_slice(&response_vec[..rsp_sz], GFP_KERNEL)?;
 
         if len
             < core::mem::size_of::<GetDigestsRsp>()
@@ -735,6 +788,14 @@ fn get_cert_exchange<'a>(
         response_vec.truncate(len);
 
         let response: &GetCertificateRsp = Untrusted::new(response_vec.as_slice()).validate()?;
+        let rsp_sz = core::mem::size_of::<SpdmHeader>() + 4 + response.portion_length as usize;
+
+        if rsp_sz > response_vec.len() {
+            return Err(EIO);
+        }
+
+        self.transcript
+            .extend_from_slice(&response_vec[..rsp_sz], GFP_KERNEL)?;
 
         if len
             < core::mem::size_of::<GetCertificateRsp>()
@@ -990,4 +1051,180 @@ pub(crate) fn validate_cert_chain(&mut self, slot: u8) -> Result<(), Error> {
 
         Ok(())
     }
+
+    pub(crate) fn challenge_rsp_len(&mut self, nonce_len: usize, opaque_len: usize) -> usize {
+        // No measurement summary hash requested (MSHLength == 0)
+        let mut length =
+            core::mem::size_of::<SpdmHeader>() + self.hash_len + nonce_len + opaque_len + 2;
+
+        if self.version >= SPDM_VER_13 {
+            length += 8;
+        }
+
+        length + self.sig_len
+    }
+
+    fn verify_signature(&mut self, signature: &mut [u8]) -> Result<(), Error> {
+        let mut sig = bindings::public_key_signature::default();
+        let mut mhash: KVec<u8> = KVec::new();
+
+        sig.s = signature as *mut _ as *mut u8;
+        sig.s_size = self.sig_len as u32;
+        sig.encoding = self.base_asym_enc.as_ptr() as *const u8;
+        sig.hash_algo = self.base_hash_alg_name.as_ptr() as *const u8;
+
+        let mut m: KVec<u8> = KVec::new();
+        m.extend_with(SPDM_COMBINED_PREFIX_SZ + self.hash_len, 0, GFP_KERNEL)?;
+
+        if let Some(desc) = &mut self.desc {
+            desc.tfm = self.shash;
+
+            unsafe {
+                to_result(bindings::crypto_shash_digest(
+                    *desc,
+                    self.transcript.as_ptr(),
+                    (self.transcript.len() - self.sig_len) as u32,
+                    m[SPDM_COMBINED_PREFIX_SZ..].as_mut_ptr(),
+                ))?;
+            };
+        } else {
+            return Err(EPROTO);
+        }
+
+        if self.version <= SPDM_VER_11 {
+            sig.m = m[SPDM_COMBINED_PREFIX_SZ..].as_mut_ptr();
+        } else {
+            let major = self.version >> 4;
+            let minor = self.version & 0xF;
+
+            let prefix = CString::try_from_fmt(fmt!("dmtf-spdm-v{major:x}.{minor:x}.*dmtf-spdm-v{major:x}.{minor:x}.*dmtf-spdm-v{major:x}.{minor:x}.*dmtf-spdm-v{major:x}.{minor:x}.*"))?;
+            let mut buf = prefix.into_vec();
+            let zero_pad_len = SPDM_COMBINED_PREFIX_SZ - SPDM_PREFIX_SZ - SPDM_CONTEXT.len() - 1;
+
+            buf.extend_with(zero_pad_len, 0, GFP_KERNEL)?;
+            buf.extend_from_slice(SPDM_CONTEXT.as_bytes(), GFP_KERNEL)?;
+
+            if buf.len() != SPDM_COMBINED_PREFIX_SZ {
+                pr_err!("combined_spdm_prefix calculation is incorrect");
+                return Err(EPROTO);
+            }
+
+            m[..SPDM_COMBINED_PREFIX_SZ].copy_from_slice(&buf);
+
+            mhash.extend_with(self.hash_len, 0, GFP_KERNEL)?;
+
+            if let Some(desc) = &mut self.desc {
+                desc.tfm = self.shash;
+
+                unsafe {
+                    to_result(bindings::crypto_shash_digest(
+                        *desc,
+                        m.as_ptr(),
+                        m.len() as u32,
+                        mhash.as_mut_ptr(),
+                    ))?;
+                };
+            } else {
+                return Err(EPROTO);
+            }
+
+            sig.m = mhash.as_mut_ptr();
+        }
+
+        sig.m_size = self.hash_len as u32;
+
+        if let Some(leaf_key) = self.leaf_key {
+            unsafe { to_result(bindings::public_key_verify_signature(leaf_key, &sig)) }
+        } else {
+            return Err(EPROTO);
+        }
+    }
+
+    pub(crate) fn challenge(&mut self, slot: u8) -> Result<(), Error> {
+        let mut request = ChallengeReq::default();
+        request.version = self.version;
+        request.param1 = slot;
+
+        let nonce_len = request.nonce.len();
+
+        if self.next_nonce.len() > 0 {
+            let request_nonce_len = request.nonce.len();
+
+            if self.next_nonce.len() == request_nonce_len {
+                request
+                    .nonce
+                    .copy_from_slice(&self.next_nonce[..request_nonce_len]);
+            } else {
+                return Err(EINVAL);
+            }
+
+            self.next_nonce.clear();
+        } else {
+            unsafe {
+                bindings::get_random_bytes(&mut request.nonce as *mut _ as *mut c_void, nonce_len)
+            };
+        }
+
+        let req_sz = if self.version <= SPDM_VER_12 {
+            offset_of!(ChallengeReq, context)
+        } else {
+            core::mem::size_of::<ChallengeReq>()
+        };
+
+        let rsp_sz = self.challenge_rsp_len(nonce_len, SPDM_MAX_OPAQUE_DATA);
+
+        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
+        let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
+
+        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, rsp_sz, GFP_KERNEL)?;
+
+        let rc = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
+
+        // The transport must report a length within the buffer we provided.
+        if rc < core::mem::size_of::<ChallengeRsp>() {
+            pr_err!("Truncated challenge response\n");
+            return Err(EIO);
+        }
+        response_vec.truncate(rc);
+
+        let _response: &ChallengeRsp = Untrusted::new(response_vec.as_slice()).validate()?;
+
+        // MSHLength is 0 as no measurement summary hash requested
+        let opaque_len_offset = core::mem::size_of::<SpdmHeader>() + self.hash_len + nonce_len;
+
+        if opaque_len_offset + 2 > response_vec.len() {
+            return Err(EIO);
+        }
+
+        let opaque_len = u16::from_le_bytes(
+            response_vec[opaque_len_offset..(opaque_len_offset + 2)]
+                .try_into()
+                .unwrap_or([0, 0]),
+        );
+
+        let rsp_sz = self.challenge_rsp_len(nonce_len, opaque_len as usize);
+
+        if rsp_sz > response_vec.len() {
+            pr_err!("Truncated challenge response\n");
+            return Err(EIO);
+        }
+
+        self.transcript
+            .extend_from_slice(&response_vec[..rsp_sz], GFP_KERNEL)?;
+
+        /* Verify signature at end of transcript against leaf key */
+        let sig_start = rsp_sz - self.sig_len;
+        let signature = &mut response_vec[sig_start..rsp_sz];
+
+        match self.verify_signature(signature) {
+            Ok(()) => {
+                pr_info!("Authenticated with certificate slot {slot}\n");
+                Ok(())
+            }
+            Err(e) => {
+                pr_err!("Cannot verify challenge_auth signature: {e:?}\n");
+                Err(EPROTO)
+            }
+        }
+    }
 }
diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
index 2584bed73979..f623ac1d2860 100644
--- a/lib/rspdm/validator.rs
+++ b/lib/rspdm/validator.rs
@@ -28,6 +28,7 @@
 
 use crate::consts::{
     SPDM_ASYM_ALGOS,
+    SPDM_CHALLENGE,
     SPDM_CTEXPONENT,
     SPDM_GET_CAPABILITIES,
     SPDM_GET_CERTIFICATE,
@@ -491,3 +492,63 @@ fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
         Ok(rsp)
     }
 }
+
+#[repr(C, packed)]
+pub(crate) struct ChallengeReq {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+
+    pub(crate) nonce: [u8; 32],
+    pub(crate) context: [u8; 8],
+}
+
+impl Default for ChallengeReq {
+    fn default() -> Self {
+        ChallengeReq {
+            version: 0,
+            code: SPDM_CHALLENGE,
+            param1: 0,
+            param2: 0,
+            nonce: [0; 32],
+            context: [0; 8],
+        }
+    }
+}
+
+#[repr(C, packed)]
+pub(crate) struct ChallengeRsp {
+    pub(crate) version: u8,
+    pub(crate) code: u8,
+    pub(crate) param1: u8,
+    pub(crate) param2: u8,
+
+    pub(crate) cert_chain_hash: __IncompleteArrayField<u8>,
+    pub(crate) nonce: [u8; 32],
+    pub(crate) message_summary_hash: __IncompleteArrayField<u8>,
+
+    pub(crate) opaque_data_len: u16,
+    pub(crate) opaque_data: __IncompleteArrayField<u8>,
+
+    pub(crate) context: [u8; 8],
+    pub(crate) signature: __IncompleteArrayField<u8>,
+}
+
+impl<'a> Validate<Untrusted<&'a [u8]>> for &'a ChallengeRsp {
+    type Err = Error;
+
+    fn validate(unvalidated: &[u8]) -> Result<Self, Self::Err> {
+        if unvalidated.len() < mem::size_of::<ChallengeRsp>() {
+            return Err(EINVAL);
+        }
+
+        let ptr = unvalidated.as_ptr();
+        // CAST: `ChallengeRsp` only contains integers and has `repr(C)`.
+        let ptr = ptr.cast::<ChallengeRsp>();
+        // SAFETY: `ptr` came from a reference and the cast above is valid.
+        let rsp: &ChallengeRsp = unsafe { &*ptr };
+
+        Ok(rsp)
+    }
+}
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 5cc71552b524..f3d3f6e9f60a 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -31,6 +31,7 @@
 #include <linux/acpi.h>
 #include <linux/gpu_buddy.h>
 #include <crypto/hash.h>
+#include <crypto/public_key.h>
 #include <drm/drm_device.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
-- 
2.55.0

Re: [PATCH v3 06/21] X.509: Move certificate length retrieval into new helper

[sashiko-bot]

> From: Lukas Wunner <lukas@wunner.de>
> 
> The upcoming in-kernel SPDM library (Security Protocol and Data Model,
> https://www.dmtf.org/dsp/DSP0274) needs to retrieve the length from
> ASN.1 DER-encoded X.509 certificates.
> 
> Such code already exists in x509_load_certificate_list(), so move it
> into a new helper for reuse by SPDM.
> 
> Export the helper so that SPDM can be tristate.  (Some upcoming users of
> the SPDM libray may be modular, such as SCSI and ATA.)
> 
> No functional change intended.
> 
> Signed-off-by: Lukas Wunner <lukas@wunner.de>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=6

Re: [PATCH v3 08/21] rust: error: impl From<FromBytesWithNulError> for Kernel Error

[sashiko-bot]

> From: Alistair Francis <alistair.francis@wdc.com>
> 
> Implement From<FromBytesWithNulError> for the Kernel Error type as we
> will use it in a future patch.
> 
> As this is now generally available we can remove it from the test case
> as well.
> 
> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
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Re: [PATCH v3 07/21] rust: add bindings for hash.h

[sashiko-bot]

> From: Alistair Francis <alistair.francis@wdc.com>
> 
> Make the functions crypto_shash_descsize(), crypto_shash_digestsize()
> and crypto_free_shash() available to Rust.
> 
> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
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Re: [PATCH v3 01/21] rust: transmute: add `cast_slice[_mut]` functions

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [High] The `# Safety` contract for `cast_slice` and `cast_slice_mut` is incomplete, omitting critical requirements regarding bit-pattern validity and interior mutability.
- [Low] The small abstraction functions `cast_slice` and `cast_slice_mut` are missing `#[inline]` attributes.
- [Low] Import formatting does not follow the kernel vertical import style.
--

commit d8c311b266bb9a64cb5ebd99f708e41b6412ae21
Author: Benno Lossin <lossin@kernel.org>

rust: transmute: add cast_slice[_mut] functions

This commit introduces functions to enable casting slices with only a single
unsafe block.

Message-ID: <20250814124424.516191-2-lossin@kernel.org>

> diff --git a/rust/kernel/transmute.rs b/rust/kernel/transmute.rs
> index 654b5ede2fe29..c1282fcc9e651 100644
> --- a/rust/kernel/transmute.rs
> +++ b/rust/kernel/transmute.rs
> @@ -3,6 +3,7 @@
>  //! Traits for transmuting types.
>  
>  use core::mem::size_of;
> +use core::slice;

[Severity: Low]
Is this import formatting intentional? The subsystem coding guidelines
specify following the kernel vertical import style, which would group this
with the existing core import as use core::{mem::size_of, slice};.

[ ... ]

> +/// # Safety
> +///
> +/// - T and U must have the same layout.

[Severity: High]
Is this safety contract complete? It appears to omit requirements regarding
bit-pattern validity and interior mutability. For example, if a caller uses
types where values of T are not valid bit-patterns for U, could this lead
to undefined behavior despite adhering to the stated layout constraint?

> +pub unsafe fn cast_slice<T, U>(slice: &[T]) -> &[U] {

[Severity: Low]
Does this function need an inline attribute? As a small abstraction wrapper
forwarding to standard library slice functions within the kernel crate, the
guidelines indicate it should be annotated with #[inline] to ensure optimal
code generation across crate boundaries.

[ ... ]

> +/// # Safety
> +///
> +/// - T and U must have the same layout.

[Severity: High]
Does the mutable variant's safety contract also need to specify bit-pattern
validity in both directions? If a caller writes a valid U that is an
invalid bit-pattern for T, it seems this could cause undefined behavior
when the slice reverts to a mutable slice of T. Should it also explicitly
forbid introducing interior mutability?

> +pub unsafe fn cast_slice_mut<T, U>(slice: &mut [T]) -> &mut [U] {

[Severity: Low]
As with cast_slice, should this thin abstraction wrapper also include the
#[inline] attribute?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=1

Re: [PATCH v3 04/21] X.509: Make certificate parser public

[sashiko-bot]

> From: Lukas Wunner <lukas@wunner.de>
> 
> The upcoming support for PCI device authentication with CMA-SPDM
> (PCIe r6.1 sec 6.31) requires validating the Subject Alternative Name
> in X.509 certificates.
> 
> High-level functions for X.509 parsing such as key_create_or_update()
> throw away the internal, low-level struct x509_certificate after
> extracting the struct public_key and public_key_signature from it.
> The Subject Alternative Name is thus inaccessible when using those
> functions.
> 
> Afford CMA-SPDM access to the Subject Alternative Name by making struct
> x509_certificate public, together with the functions for parsing an
> X.509 certificate into such a struct and freeing such a struct.
> 
> No functional change intended.
> 
> Signed-off-by: Lukas Wunner <lukas@wunner.de>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=4

Re: [PATCH v3 05/21] X.509: Parse Subject Alternative Name in certificates

[sashiko-bot]

> From: Lukas Wunner <lukas@wunner.de>
> 
> The upcoming support for PCI device authentication with CMA-SPDM
> (PCIe r6.1 sec 6.31) requires validating the Subject Alternative Name
> in X.509 certificates.
> 
> Store a pointer to the Subject Alternative Name upon parsing for
> consumption by CMA-SPDM.
> 
> Signed-off-by: Lukas Wunner <lukas@wunner.de>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=5

Re: [PATCH v3 13/21] PCI/CMA: Validate Subject Alternative Name in certificates

[sashiko-bot]

> From: Lukas Wunner <lukas@wunner.de>
> 
> PCIe r6.1 sec 6.31.3 stipulates requirements for Leaf Certificates
> presented by devices, in particular the presence of a Subject Alternative
> Name which encodes the Vendor ID, Device ID, Device Serial Number, etc.
> 
> This prevents a mismatch between the device identity in Config Space and
> the certificate.  A device cannot misappropriate a certificate from a
> different device without also spoofing Config Space.  As a corollary,
> it cannot dupe an arbitrary driver into binding to it.  Only drivers
> which bind to the device identity in the Subject Alternative Name work
> (PCIe r6.1 sec 6.31 "Implementation Note: Overview of Threat Model").
> 
> The Subject Alternative Name is signed, hence constitutes a signed copy
> of a Config Space portion.  It's the same concept as web certificates
> [ ... ]
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # except ASN.1
> [ Changed by AF:
>  - Fixup a few issues caught by Sashiko
> ]
> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=13

Re: [PATCH v3 15/21] lib: rspdm: Support SPDM get_capabilities

[sashiko-bot]

> From: Alistair Francis <alistair@alistair23.me>
> 
> Support the GET_CAPABILITIES SPDM command.
> 
> Signed-off-by: Alistair Francis <alistair@alistair23.me>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=15

Re: [PATCH v3 10/21] PCI/TSM: Rename pf0 to host

[sashiko-bot]

> From: Alistair Francis <alistair.francis@wdc.com>
> 
> Rename pci_tsm_pf0 to pci_tsm_host (and rename variables and function
> names from pf0 to host) as part of converting pci_tsm_host
> to be any device that knows how to speak any of CMA, IDE, or
> TDISP.
> 
> This commit just renames the functions and provides no functional
> change. That will happen in the next commit.
> 
> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=10

Re: [PATCH v3 03/21] rust: validate: add `Validate` trait

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [Low] The small wrapper functions `validate`, `validate_ref`, and `validate_mut` in the `Untrusted` type are missing the `#[inline]` attribute, violating subsystem guidelines.

Pre-existing issues:
- [High] This problem wasn't introduced by this patch, but transmuting references between `Vec<T, A>` and `Vec<Untrusted<T>, A>` via pointer cast is Undefined Behavior because `Vec` lacks a guaranteed memory layout.
--

commit 6a4bc1cc90cb4c5dd96a67a8f893828d2d0c3473
Author: Benno Lossin <lossin@kernel.org>

rust: validate: add `Validate` trait

Introduce the `Validate<Input>` trait and functions to validate
`Untrusted<T>` using said trait.

> diff --git a/rust/kernel/validate.rs b/rust/kernel/validate.rs
> index 2b28625c25efe..663681b633c86 100644
> --- a/rust/kernel/validate.rs
> +++ b/rust/kernel/validate.rs
> @@ -107,6 +110,30 @@ pub fn new(value: T) -> Self
>      {
>          Self(value)
>      }
> +
> +    /// Validate the underlying untrusted data.
> +    ///
> +    /// See the [`Validate`] trait for more information.
> +    pub fn validate<V: Validate<Self>>(self) -> Result<V, V::Err>
> +    where
> +        T: Sized,
> +    {
> +        V::validate(self.0)
> +    }
> +
> +    /// Validate the underlying untrusted data.
> +    ///
> +    /// See the [`Validate`] trait for more information.
> +    pub fn validate_ref<'a, V: Validate<&'a Self>>(&'a self) -> Result<V, V::Err> {
> +        V::validate(&self.0)
> +    }
> +
> +    /// Validate the underlying untrusted data.
> +    ///
> +    /// See the [`Validate`] trait for more information.
> +    pub fn validate_mut<'a, V: Validate<&'a mut Self>>(&'a mut self) -> Result<V, V::Err> {
> +        V::validate(&mut self.0)
> +    }

[Severity: Low]
Should these small wrapper functions be annotated with #[inline]?

[ ... ]

>  impl<T, A: Allocator> Deref for Untrusted<Vec<T, A>> {
>      type Target = Vec<Untrusted<T>, A>;
>  
>      fn deref(&self) -> &Self::Target {
>          let ptr: *const Untrusted<Vec<T, A>> = self;
>          // CAST: `Untrusted<T>` transparently wraps `T`.
>          let ptr: *const Vec<Untrusted<T>, A> = ptr.cast();
>          // SAFETY: `ptr` is derived from the reference `self`.
>          unsafe { &*ptr }
>      }
>  }
>  
>  impl<T, A: Allocator> DerefMut for Untrusted<Vec<T, A>> {
>      fn deref_mut(&mut self) -> &mut Self::Target {
>          let ptr: *mut Untrusted<Vec<T, A>> = self;
>          // CAST: `Untrusted<T>` transparently wraps `T`.
>          let ptr: *mut Vec<Untrusted<T>, A> = ptr.cast();
>          // SAFETY: `ptr` is derived from the reference `self`.
>          unsafe { &mut *ptr }
>      }
>  }

[Severity: High]
This isn't a bug introduced by this patch, but does casting pointers between
Vec<T, A> and Vec<Untrusted<T>, A> cause Undefined Behavior?

Since Vec<T, A> uses the default #[repr(rust)] representation, it does not
guarantee stable field ordering. The Rust Reference explicitly states that
pointer-casting between two generic types with the default representation is
Undefined Behavior, even if their type arguments share identical memory
layouts.

If the compiler orders fields differently between Vec<T, A> and
Vec<Untrusted<T>, A>, could dereferencing the casted pointer or swapping
values corrupt memory?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=3

Re: [PATCH v3 14/21] lib: rspdm: Support SPDM get_version

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The newly added `kernel::sync` import violates the kernel vertical import style guidelines.
--

commit 2c0be141f2603418ed69b0153c6ee75043525d1f
Author: Alistair Francis <alistair@alistair23.me>

lib: rspdm: Support SPDM get_version

Support the GET_VERSION SPDM command.

[ ... ]

> diff --git a/lib/rspdm/lib.rs b/lib/rspdm/lib.rs
> index 1883579b817aa..58d86ea06fd93 100644
> --- a/lib/rspdm/lib.rs
> +++ b/lib/rspdm/lib.rs
> @@ -18,8 +18,10 @@
>      c_int,
>      c_void, //
>  };
> +use core::pin::Pin;
>  use core::ptr;
>  use kernel::prelude::*;
> +use kernel::sync::{new_mutex, Mutex};

[Severity: Low]
Should the kernel::sync import in lib/rspdm/lib.rs be reformatted to follow
the kernel vertical import style guidelines rather than grouping multiple items
on a single line?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=14

Re: [PATCH v3 09/21] lib: rspdm: Initial commit of Rust SPDM

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] RSPDM uses `select` for config options without inheriting their dependencies, leading to unmet dependency warnings.
--

commit 752bdb39dced6672e12844f92653f4013c5aea48
Author: Alistair Francis <alistair@alistair23.me>

lib: rspdm: Initial commit of Rust SPDM

This is the initial commit of the Rust SPDM library.

> diff --git a/lib/Kconfig b/lib/Kconfig
> index 4e6b34c3346d5..b1792db6ddf07 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
[ ... ]
> @@ -588,6 +588,21 @@ config LWQ_TEST
>  	help
>  	  Run boot-time test of light-weight queuing.
>  
> +config RSPDM
> +	bool "Rust SPDM"
> +	depends on RUST
> +	select ASYMMETRIC_KEY_TYPE
> +	select CRYPTO
> +	select X509_CERTIFICATE_PARSER

[Severity: Low]
Will selecting these config options without inheriting their dependencies
cause Kconfig unmet dependency warnings?

ASYMMETRIC_KEY_TYPE depends on KEYS, and X509_CERTIFICATE_PARSER depends on
ASYMMETRIC_PUBLIC_KEY_SUBTYPE. If a user enables RSPDM without having KEYS
enabled, Kconfig will issue an unmet direct dependency warning and
potentially cause silent build failures.

Should this config add "depends on KEYS" and either depend on or select
ASYMMETRIC_PUBLIC_KEY_SUBTYPE?

> +	help
> +	  The Rust implementation of the Security Protocol and Data Model (SPDM)
> +	  allows for device authentication, measurement, key exchange and
> +	  encrypted sessions.
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=9

Re: [PATCH v3 02/21] rust: create basic untrusted data API

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Undefined Behavior due to missing layout guarantees when transmuting `Vec<T, A>` to `Vec<Untrusted<T>, A>`.
- [Low] Small abstraction functions in the `kernel` crate are missing `#[inline]` annotations.
--

commit a2ef24201e92da02db41c39bbc750b20f5e2ce5b
Author: Benno Lossin <lossin@kernel.org>

rust: create basic untrusted data API

This commit introduces an Untrusted<T> wrapper type to explicitly mark
and validate external data before use. The API provides Deref and DerefMut
implementations to allow working with untrusted slices and vectors.

> diff --git a/rust/kernel/validate.rs b/rust/kernel/validate.rs
> new file mode 100644
> index 0000000000000..2b28625c25efe
> --- /dev/null
> +++ b/rust/kernel/validate.rs

[ ... ]

> +impl<T: ?Sized> Untrusted<T> {

[ ... ]

> +    pub fn new(value: T) -> Self
> +    where
> +        T: Sized,
> +    {
> +        Self(value)
> +    }

[Severity: Low]
Could this small abstraction function be annotated with #[inline]?

The Rust Subsystem coding guidelines suggest that small functions in
abstractions like the kernel crate should be marked as inline to ensure
optimal code generation.

> +}
> +
> +impl<T> Deref for Untrusted<[T]> {
> +    type Target = [Untrusted<T>];
> +
> +    fn deref(&self) -> &Self::Target {
> +        // SAFETY: `Untrusted<T>` transparently wraps `T`.
> +        unsafe { cast_slice(&self.0) }
> +    }
> +}

[Severity: Low]
Should this small trait method also have an #[inline] annotation?

> +
> +impl<T> DerefMut for Untrusted<[T]> {
> +    fn deref_mut(&mut self) -> &mut Self::Target {
> +        // SAFETY: `Untrusted<T>` transparently wraps `T`.
> +        unsafe { cast_slice_mut(&mut self.0) }
> +    }
> +}

[Severity: Low]
Would an #[inline] annotation be appropriate for this deref_mut implementation
as well?

> +
> +impl<T, A: Allocator> Deref for Untrusted<Vec<T, A>> {
> +    type Target = Vec<Untrusted<T>, A>;
> +
> +    fn deref(&self) -> &Self::Target {
> +        let ptr: *const Untrusted<Vec<T, A>> = self;
> +        // CAST: `Untrusted<T>` transparently wraps `T`.
> +        let ptr: *const Vec<Untrusted<T>, A> = ptr.cast();
> +        // SAFETY: `ptr` is derived from the reference `self`.
> +        unsafe { &*ptr }
> +    }
> +}

[Severity: High]
Is it possible to add an #[inline] annotation here?

Additionally, does this pointer cast rely on layout guarantees that the
compiler does not provide?

Vec is a #[repr(Rust)] type, which does not guarantee stable or identical
layouts across different generic monomorphizations. Even though Untrusted<T>
is #[repr(transparent)] over T, Vec<T, A> and Vec<Untrusted<T>, A> are
distinct monomorphizations.

If the compiler orders the internal fields differently, transmuting between
these types could lead to memory corruption. The standard way to soundly
convert a vector's element type is by deconstructing it via into_raw_parts
and reconstructing it with from_raw_parts, but this cannot be done for
references.

Are there alternative ways to expose this untrusted vector data safely?

> +
> +impl<T, A: Allocator> DerefMut for Untrusted<Vec<T, A>> {
> +    fn deref_mut(&mut self) -> &mut Self::Target {
> +        let ptr: *mut Untrusted<Vec<T, A>> = self;
> +        // CAST: `Untrusted<T>` transparently wraps `T`.
> +        let ptr: *mut Vec<Untrusted<T>, A> = ptr.cast();
> +        // SAFETY: `ptr` is derived from the reference `self`.
> +        unsafe { &mut *ptr }
> +    }
> +}

[Severity: High]
Could this method be annotated with #[inline] as well?

Similar to the deref implementation above, can this pointer cast invoke
undefined behavior by transmuting between two distinct #[repr(Rust)] types?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=2

Re: [PATCH v3 20/21] rust: allow extracting the buffer from a CString

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The `into_vec` method returns a `KVec<u8>` that includes the NUL terminator, deviating from standard Rust `std::ffi::CString` conventions and failing to indicate this in its name, creating a high risk of subtle logic errors.
--

commit c0d8b032f9c0888c9ca7f0f193ec4c7fb49a4747
Author: Alistair Francis <alistair@alistair23.me>

rust: allow extracting the buffer from a CString

This commit adds an into_vec() method to the kernel's CString type. It
allows callers to consume the CString and extract the underlying KVec
buffer.

> diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
> index a556788bcc5e9..3fd8a218547f4 100644
> --- a/rust/kernel/str.rs
> +++ b/rust/kernel/str.rs
> @@ -870,6 +870,12 @@ pub fn try_from_fmt(args: fmt::Arguments<'_>) -> Result<Self, Error> {
>          // exist in the buffer.
>          Ok(Self { buf })
>      }
> +
> +    /// Return the internal buffer while consuming the original [`CString`]
> +    #[inline]
> +    pub fn into_vec(self) -> KVec<u8> {
> +        self.buf
> +    }

[Severity: Medium]
Will this return a vector that includes the NUL terminator?

In standard Rust, std::ffi::CString::into_bytes() strips the NUL byte, and
there is a separate into_bytes_with_nul() method to retain it. Because this
method is named into_vec() and the documentation doesn't specify how the
NUL byte is handled, could callers unknowingly process an extra NUL byte
if they assume standard behavior?

Could this lead to a regression with incorrect payload lengths if the array
is passed to external subsystems expecting a standard string length?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=20

Re: [PATCH v3 17/21] lib: rspdm: Support SPDM get_digests

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [High] Buffer under-allocation for SPDM 1.3+ GET_DIGESTS responses leading to transport failure, transcript truncation, and EIO crashes.
- [Medium] The GET_DIGESTS implementation validates the payload length but completely discards the returned certificate digests.
- [Low] An undersized/truncated GET_DIGESTS response incorrectly logs an 'Overflow' error.
--

commit 7b16689f564246befd0f0c43fa0d4515876746e6
Author: Alistair Francis <alistair@alistair23.me>

lib: rspdm: Support SPDM get_digests

This commit adds support for the GET_DIGESTS SPDM command.

> diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
> index b78086c753702..131c22319b262 100644
> --- a/lib/rspdm/state.rs
> +++ b/lib/rspdm/state.rs
[ ... ]
> @@ -612,4 +630,64 @@ pub(crate) fn negotiate_algs(&mut self) -> Result<(), Error> {
>  
>          Ok(())
>      }
> +
> +    pub(crate) fn get_digests(&mut self) -> Result<(), Error> {
> +        let mut request = GetDigestsReq::default();
> +        request.version = self.version;
> +
> +        let req_sz = core::mem::size_of::<GetDigestsReq>();
> +        let rsp_sz = core::mem::size_of::<GetDigestsRsp>() + SPDM_SLOTS * self.hash_len;

[Severity: High]
Does this calculation fail to account for SPDM 1.3+ fields like KeyPairID,
CertificateInfo, and KeyUsageMask?

For SPDM 1.3+ compliant responders, up to 32 bytes of additional fields
can be returned. Because param2 is a bitmask of provisioned slots rather
than a count, any device using slots >= 4 will produce a response size far
larger than the allocated buffer, which could trigger an EIO crash.

Even for lower slots, this calculation omits the 1.3 fields from the
transcript, which could cause a permanent signature verification failure
in challenge authentication due to transcript desynchronization.

> +
> +        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
> +        let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
> +
> +        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, rsp_sz, GFP_KERNEL)?;
> +
> +        let len = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
> +
> +        // The transport must report a length within the buffer we provided.
> +        if len > response_vec.len() {
> +            pr_err!("Overflowed digests response\n");
> +            return Err(EIO);
> +        }
> +        response_vec.truncate(len);
> +
> +        let response: &GetDigestsRsp = Untrusted::new(response_vec.as_slice()).validate()?;

[Severity: Medium]
Does this completely discard the returned certificate digests?

The SPDM specification mandates that requesters compare the hash of the
certificate chain with the digest returned in get_digests. There doesn't
seem to be any storage for these digests in SpdmState, meaning this
cryptographic binding between the get_digests response and the certificate
chain downloaded in get_certificate might never be verified.

> +
> +        if len
> +            < core::mem::size_of::<GetDigestsRsp>()
> +                + response.param2.count_ones() as usize * self.hash_len
> +        {
> +            pr_err!("Overflowed digests response\n");

[Severity: Low]
Should this error message indicate an underflow or truncation instead?

This condition triggers when the transport returns fewer bytes than expected
for the number of provisioned slots. Logging "Overflowed" might be
misleading when debugging transport truncation or packet loss.

> +            return Err(EIO);
> +        }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=17

Re: [PATCH v3 12/21] PCI/CMA: Add a PCI TSM CMA driver using SPDM

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The CMA driver's probe callback unconditionally treats every probed device as a TSM host, which triggers spurious kernel warnings for sub-functions like VFs.
--

commit e6e460ef636dca826aac1d314b1cb072ffd45217
Author: Alistair Francis <alistair.francis@wdc.com>

PCI/CMA: Add a PCI TSM CMA driver using SPDM

This commit adds a Component Measurement and Authentication (CMA) driver
using SPDM. It utilizes a PCI DOE mailbox as a transport to authenticate
devices during enumeration and integrates with the TSM subsystem.

Link: http://lore.kernel.org/69976d7d39c60_2f4a1009@dwillia2-mobl4.notmuch

> diff --git a/drivers/pci/cma.c b/drivers/pci/cma.c
> new file mode 100644
> index 0000000000000..9f2cc0b2ec8a7
> --- /dev/null
> +++ b/drivers/pci/cma.c

[ ... ]

> +static struct pci_tsm *pci_cma_tsm_probe(struct tsm_dev *tsm_dev,
> +					 struct pci_dev *pdev)
> +{
> +	struct pci_cma_tsm *cma;
> +	int rc;
> +
> +	cma = kzalloc(sizeof(*cma), GFP_KERNEL);
> +	if (!cma)
> +		return NULL;
> +
> +	rc = pci_tsm_host_constructor(pdev, &cma->host, tsm_dev);

[Severity: Medium]
Will this unconditional call trigger spurious warnings for sub-functions
like VFs?

When VFs are instantiated on an already-connected TSM host, pci_tsm_init()
finds the host DSM and calls the probe function for the VF. Here in
pci_cma_tsm_probe() from drivers/pci/cma.c, we unconditionally call
pci_tsm_host_constructor() on every probed device.

Because VFs lack CMA mailboxes, this triggers spurious "TSM init failure, no
CMA mailbox" warnings in the kernel log for every VF probed.

Would it make sense to add an is_pci_tsm_host(pdev) check here before
calling pci_tsm_host_constructor(), to ensure we only attempt to initialize
it when appropriate?

> +	if (rc) {
> +		kfree(cma);
> +		return NULL;
> +	}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=12

Re: [PATCH v3 18/21] lib: rspdm: Support SPDM get_certificate

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [High] `request.length` is byte-swapped to little-endian but then immediately used as a native `usize` for buffer resizing, leading to incorrect sizing on big-endian architectures.
- [High] Potential integer underflow and kernel panic if `self.transport_sz` is less than the GetCertificateRsp header size (8 bytes).
- [Medium] Inconsistent masking of SPDM reserved bits in param1 causes spurious authentication failures.
--

commit 3d050ea39968a6dc6cb0a982af8f1746df8a12b6
Author: Alistair Francis <alistair@alistair23.me>

lib: rspdm: Support SPDM get_certificate
    
Support the GET_CERTIFICATE SPDM command.

The kernel will send a GET_CERTIFICATE request to the the responder and
then iterate over all of the certificates returned.

> diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
> index 131c22319b262..1e8a4402e6342 100644
> --- a/lib/rspdm/state.rs
> +++ b/lib/rspdm/state.rs
[ ... ]
> @@ -690,4 +703,147 @@ pub(crate) fn get_digests(&mut self) -> Result<(), Error> {
[ ... ]
> +    pub(crate) fn get_certificate(&mut self, slot: u8) -> Result<(), Error> {
> +        let mut request = GetCertificateReq::default();
> +        request.version = self.version;
> +        request.param1 = slot;
> +
> +        let req_sz = core::mem::size_of::<GetCertificateReq>();
> +        let rsp_sz = (core::mem::size_of::<GetCertificateRsp>() as u32 + u16::MAX as u32)
> +            .min(self.transport_sz) as usize;
> +
> +        request.offset = 0;
> +        request.length = ((rsp_sz - core::mem::size_of::<GetCertificateRsp>()) as u16).to_le();

[Severity: High]
Can this subtraction underflow and cause a kernel panic?

If a malicious or misconfigured device advertises a data transfer size during
the capabilities exchange that is smaller than 8 bytes, self.transport_sz
will be smaller than core::mem::size_of::<GetCertificateRsp>(). 

This would cause rsp_sz - core::mem::size_of::<GetCertificateRsp>() to
underflow and panic.

> +
> +        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
> +        let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
> +
> +        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, rsp_sz, GFP_KERNEL)?;
> +
> +        let response = self.get_cert_exchange(request_buf, &mut response_vec)?;
> +
> +        if response.param1 != slot {

[Severity: Medium]
Will this initial slot verification erroneously reject valid responses?

Unlike the check inside the while loop below which uses
(response.param1 & 0xF) != slot, this check strictly compares param1
without masking reserved bits.

If a compliant external device sets bits 4-7 in param1 during a
certificate response, this will cause spurious authentication failures.

> +            pr_err!("Invalid slot response\n");
> +            return Err(EPROTO);
> +        }
> +
> +        let portion_length = response.portion_length;
> +        let rem_length = response.remainder_length;
[ ... ]
> +        while remainder_length > 0 {
> +            request.offset = offset.to_le();
> +            request.length =
> +                ((remainder_length.min(rsp_sz - core::mem::size_of::<GetCertificateRsp>())) as u16)

[Severity: High]
Does this underflow the same way as the first request if rsp_sz is less than
core::mem::size_of::<GetCertificateRsp>()?

> +                    .to_le();
> +
> +            let request_buf =
> +                unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
> +
> +            response_vec.resize(
> +                request.length as usize + core::mem::size_of::<GetCertificateRsp>(),

[Severity: High]
Does this correctly resize the buffer on big-endian architectures?

Since request.length was just byte-swapped to little-endian using .to_le()
above, reading it directly as a native usize on a big-endian system will
produce an incorrectly large or small size.

This could lead to ENOMEM, out-of-bounds logic failures, or panics.

> +                0,
> +                GFP_KERNEL,
> +            )?;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=18

Re: [PATCH v3 19/21] lib: rspdm: Support SPDM certificate validation

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The SPDM implementation incorrectly assumes all certificate slots share the same leaf key, violating the SPDM specification and restricting support for multi-slot responders.
--

commit b0152a815fb6a558a0d32bf4c0f287cb4d4ee1a3
Author: Alistair Francis <alistair@alistair23.me>

lib: rspdm: Support SPDM certificate validation

Support validating the SPDM certificate chain. This performs basic
sanity checks on the chain, ensures supported signatures are used,
checks against the blacklist, and stores the first leaf certificate.

> diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
> index 1e8a4402e6342..fc7df9dd7b973 100644
> --- a/lib/rspdm/state.rs
> +++ b/lib/rspdm/state.rs

[ ... ]

> @@ -846,4 +858,136 @@ pub(crate) fn get_certificate(&mut self, slot: u8) -> Result<(), Error> {

[ ... ]

> +        if let Some(prev) = prev_cert {
> +            if let Some(validate) = self.validate {
> +                // SAFETY: Call the `validate` function provided.
> +                let rc = unsafe { validate(self.dev, slot, prev) };
> +                if let Err(e) = to_result(rc) {
> +                    // SAFETY: `prev_cert` is the previously parsed
> +                    // certificate from a prior loop iteration.
> +                    unsafe { bindings::x509_free_certificate(prev) };
> +                    return Err(e);
> +                }
> +            }
> +
> +            // The leaf key is the same for all slots, so just store the first one.
> +            if self.leaf_key.is_none() {
> +                // SAFETY: `prev_cert` is the previously parsed
> +                // certificate from a prior loop iteration.
> +                self.leaf_key = unsafe { Some((*prev).pub_) };

[Severity: Medium]
Is it safe to assume all certificate slots share the same leaf key here?

According to the SPDM specification (DSP0274), devices are allowed up to 8
slots, and they can be provisioned with distinct certificate chains and
cryptographic keys (e.g., one RSA chain and one ECDSA chain).

When an SPDM responder with multiple provisioned slots connects, this logic
skips storing the leaf keys for all slots after the first one. If the responder
negotiates an algorithm that directs a challenge to a slot other than the
first one, won't authentication use the incorrect leaf key from the first slot
and cause signature verification to fail?

> +                // SAFETY: `prev_cert` is the previously parsed
> +                // certificate from a prior loop iteration. We are setting
> +                // the `pub` key to null so it isn't freed below
> +                unsafe { (*prev).pub_ = core::ptr::null_mut() };
> +            }
> +
> +            // SAFETY: `prev_cert` is the previously parsed
> +            // certificate from a prior loop iteration.
> +            unsafe { bindings::x509_free_certificate(prev) };
> +        }
> +
> +        Ok(())
> +    }
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=19

Re: [PATCH v3 11/21] PCI/TSM: Support connecting to PCIe CMA devices

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:

New issues:
- [High] Unconditional overwrite of `pdev->tsm` in `probe_fn()` causes memory leak and state corruption for independent sibling CMA hosts.
- [High] Expanding `is_pci_tsm_host()` to return true for dependent functions with CMA breaks DSM resolution, causing type confusion and preventing context cleanup.

Pre-existing issues:
- [High] AB-BA lock inversion between `pci_bus_sem` and `tsm_host->lock` in `__pci_tsm_disconnect` for upstream switch ports.
--

commit 1f366330a43aef4dbb8b7e338fe088b357fa13a0
Author: Alistair Francis <alistair.francis@wdc.com>

PCI/TSM: Support connecting to PCIe CMA devices

This patch adds support for connecting to PCIe CMA devices by modifying
is_pci_tsm_host() to allow CMA capable devices. It caches the CMA support
in struct pci_dev to avoid repeated mailbox lookups.

> diff --git a/drivers/pci/tsm.c b/drivers/pci/tsm.c
> index 10c9c6696624d..440f818ac5699 100644
> --- a/drivers/pci/tsm.c
> +++ b/drivers/pci/tsm.c

[ ... ]

> @@ -456,7 +475,7 @@ static void __pci_tsm_disconnect(struct pci_dev *pdev)
>  	 * teardown
>  	 */
>  	guard(mutex)(&tsm_host->lock);
> -	pci_tsm_walk_fns_reverse(pdev, remove_fn, NULL);
> +	pci_tsm_walk_fns_reverse(pdev, remove_fn, pdev);

[Severity: High]
This is a pre-existing issue, but does __pci_tsm_disconnect() create an
AB-BA lock inversion between pci_bus_sem and tsm_host->lock?

First, pci_tsm_unbind_all() calls pci_tsm_walk_fns_reverse(). For upstream
switch ports, this invokes pci_walk_bus_reverse(), acquiring pci_bus_sem
for read. Inside the walk, the callback __pci_tsm_unbind() acquires
tsm_host->lock, establishing a pci_bus_sem -> tsm_host->lock ordering.

Immediately after, __pci_tsm_disconnect() explicitly acquires tsm_host->lock
via guard(mutex), and then calls pci_tsm_walk_fns_reverse() (which invokes
pci_walk_bus_reverse()), attempting to acquire pci_bus_sem for read.

This reverses the acquisition order to tsm_host->lock -> pci_bus_sem, which
could lead to a deadlock when racing with bus modifications.

>  	ops->disconnect(pdev);
>  }

> diff --git a/include/linux/pci-tsm.h b/include/linux/pci-tsm.h
> index 950e2c36a4cae..f504fa6803157 100644
> --- a/include/linux/pci-tsm.h
> +++ b/include/linux/pci-tsm.h

[ ... ]

> @@ -142,6 +143,15 @@ static inline bool is_pci_tsm_host(struct pci_dev *pdev)
>  	if (pdev->is_virtfn)
>  		return false;
>  
> +	/*
> +	 * Report capable if CMA is supported, which can be supported on any PCIe
> +	 * device.
> +	 */
> +#ifdef CONFIG_PCI_DOE
> +	if (pdev->doe_cma)
> +		return true;
> +#endif
> +

[Severity: High]
Does expanding is_pci_tsm_host() to return true for dependent functions with
CMA introduce a memory leak and state corruption?

If userspace connects a dependent function (like PF1) as a CMA host first,
pci_tsm_connect() allocates PF1->tsm. If userspace subsequently connects a
TEE host (DSM) on the same device (e.g. PF0), pci_tsm_connect(PF0) walks
dependent functions and calls probe_fn(PF1, PF0).

In drivers/pci/tsm.c:probe_fn(), it unconditionally overwrites pdev->tsm:

	pdev->tsm = ops->probe(dsm_dev->tsm->tsm_dev, pdev);

Could this overwrite the existing CMA TSM context without checking or freeing
it, leaking the memory and corrupting the state?

[Severity: High]
Additionally, does returning true for dependent functions with CMA break
DSM resolution in find_dsm_dev()?

When the parent TEE DSM (PF0) calls probe_fn(PF1), the allocation path
calls find_dsm_dev(PF1). Since is_pci_tsm_host(PF1) now evaluates to true,
find_dsm_dev() incorrectly returns PF1 instead of the actual DSM (PF0).

This causes PF1 to self-identify as its own host, meaning
PF1->tsm->dsm_dev == PF1.

Later, when the parent DSM (PF0) is disconnected, remove_fn() has:

	if (!pdev->tsm || pdev->tsm->dsm_dev != host)
		return 0;

This will skip PF1 because its dsm_dev no longer matches the host, causing
the TEE context to leak. Furthermore, upon device removal,
__pci_tsm_destroy(PF1) would incorrectly treat PF1 as a host and execute the
host-only teardown path (pci_tsm_disconnect), causing type confusion.

>  	/*
>  	 * Allow for a Device Security Manager (DSM) associated with function0
>  	 * of an Endpoint to coordinate TDISP requests for other functions

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=11

Re: [PATCH v3 16/21] lib: rspdm: Support SPDM negotiate_algorithms

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Memory provenance truncation when storing a dynamically sized C struct as a statically sized Rust reference.
- [Low] Algorithm match arms become dead code under valid Kconfig combinations.
--

commit 8baafb6a67bc3beb2ad7bb9b93fd0f34551c04c9
Author: Alistair Francis <alistair@alistair23.me>

lib: rspdm: Support SPDM negotiate_algorithms

This commit adds support for the SPDM NEGOTIATE_ALGORITHMS command.
It extends SpdmState to negotiate and store cryptographic algorithms,
allocating the corresponding synchronous hash handle and context.

> diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
> index 5ef14c8ed2375..b78086c753702 100644
> --- a/lib/rspdm/state.rs
> +++ b/lib/rspdm/state.rs
[ ... ]
> @@ -373,4 +452,164 @@ pub(crate) fn get_capabilities(&mut self) -> Result<(), Error> {
>  
>          Ok(())
>      }
> +
> +    fn update_response_algs(&mut self) -> Result<(), Error> {
> +        match self.base_asym_alg {
> +            SPDM_ASYM_RSASSA_2048 => {
> +                self.sig_len = 256;
> +                self.base_asym_enc = CStr::from_bytes_with_nul(b"pkcs1\0")?;
> +            }

[Severity: Low]
Does this match arm become dead code when CONFIG_CRYPTO_RSA is disabled?

If CONFIG_CRYPTO_RSA is disabled, the SPDM_ASYM_RSA constant evaluates to 0.
Consequently, negotiate_algs() will reject RSA algorithms because they are not
present in SPDM_ASYM_ALGOS, making this match arm structurally unreachable.

Should these match arms be conditionally compiled so they don't produce dead
code under valid Kconfig combinations?

[ ... ]
> +        let desc_vec: KVec<u8> = KVec::from_elem(0u8, desc_len, GFP_KERNEL)?;
> +        // Consume the desc_vec to make sure it isn't dropped, untill we
> +        // manually drop it later
> +        let (desc_buf, _length, _capacity) = desc_vec.into_raw_parts();
> +
> +        // SAFETY: We are casting the allocation to be a shash_desc
> +        let desc = unsafe {
> +            core::mem::transmute::<*mut c_void, &mut bindings::shash_desc>(desc_buf as *mut c_void)
> +        };
> +        desc.tfm = self.shash;
> +
> +        self.desc = Some(desc);
> +
> +        /* Used frequently to compute offsets, so cache H */
> +        self.hash_len = unsafe { bindings::crypto_shash_digestsize(self.shash) as usize };
> +
> +        if let Some(desc) = &mut self.desc {
> +            // SAFETY: `self.desc` is a valid and initalised `shash_desc` sized buffer
> +            unsafe { to_result(bindings::crypto_shash_init(*desc)) }

[Severity: High]
Does transmuting the dynamically sized buffer to a static Rust reference here
cause memory provenance truncation?

When the dynamically sized buffer (which includes space for both the header
and a flexible array context) is transmuted into a statically sized Rust
reference &mut bindings::shash_desc, the Rust compiler strictly limits the
memory provenance of this reference to the header's size.

When this restricted reference is coerced back to a pointer and passed to C
functions like crypto_shash_init(), C writes into the trailing context array.
This access is out-of-bounds with respect to the Rust reference's provenance,
which triggers Undefined Behavior.

A similar issue occurs during Drop when the restricted reference is transmuted
back to a pointer to free the full capacity. Checking the end of the patch
series confirms this remains unfixed.

Would it be better to retain a raw pointer (*mut bindings::shash_desc)
instead of materializing a provenance-restricted Rust reference?

> +        } else {
> +            Err(ENOMEM)
> +        }
> +    }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=16

Re: [PATCH v3 21/21] lib: rspdm: Support SPDM challenge

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:

New issues:
- [Medium] `ChallengeRsp` struct definition misrepresents the SPDM packet format by declaring variable-sized fields in the middle of a `repr(C, packed)` struct.
- [Medium] Missing upper bound check on transport response length (`rc`) in `challenge` function.

Pre-existing issues:
- [High] Stale `leaf_key` retention across multiple SPDM authentications causes persistent authentication failures.
--

commit fe7e9708b9e2dfbb56d50564eed90c6c3454e54e
Author: Alistair Francis <alistair@alistair23.me>

lib: rspdm: Support SPDM challenge
    
This commit adds support for the CHALLENGE SPDM command in the SPDM responder
implementation.

> diff --git a/lib/rspdm/state.rs b/lib/rspdm/state.rs
> index fc7df9dd7b973..1fd691037fa57 100644
> --- a/lib/rspdm/state.rs
> +++ b/lib/rspdm/state.rs
[ ... ]
> +    fn verify_signature(&mut self, signature: &mut [u8]) -> Result<(), Error> {
[ ... ]
> +        if let Some(leaf_key) = self.leaf_key {
> +            unsafe { to_result(bindings::public_key_verify_signature(leaf_key, &sig)) }
> +        } else {
> +            return Err(EPROTO);
> +        }
> +    }

[Severity: High]
This is a pre-existing issue, but this code in verify_signature() relies on
the cached leaf_key which can lead to persistent authentication failures.

If a device is re-authenticated and its certificates have changed,
spdm_authenticate() will fetch the new certificates, but the existing code in
validate_cert_chain() only sets leaf_key if it is missing.

Will verify_signature() then attempt to verify the new signature using the
stale, previously cached leaf_key, resulting in an inevitable verification
failure during the challenge sequence?

[ ... ]
> +    pub(crate) fn challenge(&mut self, slot: u8) -> Result<(), Error> {
[ ... ]
> +        let rc = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
> +
> +        // The transport must report a length within the buffer we provided.
> +        if rc < core::mem::size_of::<ChallengeRsp>() {
> +            pr_err!("Truncated challenge response\n");
> +            return Err(EIO);
> +        }
> +        response_vec.truncate(rc);

[Severity: Medium]
Does SpdmState::challenge() miss the upper bound check on the transport
response length?

The comment notes that the transport must report a length within the buffer
provided. If a buggy transport driver returns an rc greater than
response_vec.len(), this check will pass and response_vec.truncate(rc) will
not bound the vector correctly, allowing the function to process potentially
uninitialized or out-of-bounds data later in the parsing process.

Should this also ensure that rc is less than or equal to response_vec.len()?

> diff --git a/lib/rspdm/validator.rs b/lib/rspdm/validator.rs
> index 2584bed739792..f623ac1d28606 100644
> --- a/lib/rspdm/validator.rs
> +++ b/lib/rspdm/validator.rs
[ ... ]
> +#[repr(C, packed)]
> +pub(crate) struct ChallengeRsp {
> +    pub(crate) version: u8,
> +    pub(crate) code: u8,
> +    pub(crate) param1: u8,
> +    pub(crate) param2: u8,
> +
> +    pub(crate) cert_chain_hash: __IncompleteArrayField<u8>,
> +    pub(crate) nonce: [u8; 32],

[Severity: Medium]
Does the ChallengeRsp struct definition in lib/rspdm/validator.rs misrepresent
the actual wire format of the SPDM protocol by placing a variable-sized field
before a fixed-size field?

Because __IncompleteArrayField<u8> acts as a zero-sized type, nonce and all
subsequent fields will be assigned static offsets that do not account for the
actual length of cert_chain_hash. Any future code attempting to access these
fields directly from the struct would read from the wrong offsets.

Does the struct layout need to be restructured to accurately reflect the
variable length nature of the SPDM challenge response?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260901010347.2614656-1-alistair.francis@wdc.com?part=21

Re: [PATCH v3 16/21] lib: rspdm: Support SPDM negotiate_algorithms

[Aksh Garg]

On 01/09/26 06:33, alistair23@gmail.com wrote:
> From: Alistair Francis <alistair@alistair23.me>
> 
> Support the NEGOTIATE_ALGORITHMS SPDM command.
> 
> Signed-off-by: Alistair Francis <alistair@alistair23.me>
> ---
>   lib/rspdm/consts.rs    |  56 +++++++++-
>   lib/rspdm/lib.rs       |   9 +-
>   lib/rspdm/state.rs     | 243 ++++++++++++++++++++++++++++++++++++++++-
>   lib/rspdm/validator.rs | 110 ++++++++++++++++++-
>   4 files changed, 412 insertions(+), 6 deletions(-)

[...]

> +
> +    pub(crate) fn negotiate_algs(&mut self) -> Result<(), Error> {
> +        let mut request = NegotiateAlgsReq::default();
> +        request.version = self.version;
> +
> +        if self.version >= SPDM_VER_12 && (self.rsp_caps & SPDM_KEY_EX_CAP) == SPDM_KEY_EX_CAP {
> +            request.other_params_support = SPDM_OPAQUE_DATA_FMT_GENERAL;
> +        }
> +
> +        let req_sz = core::mem::size_of::<NegotiateAlgsReq>();
> +        let rsp_sz = core::mem::size_of::<NegotiateAlgsRsp>();
> +
> +        request.length = (req_sz as u16).to_le();
> +
> +        // SAFETY: `request` is repr(C) and packed, so we can convert it to a slice
> +        let request_buf = unsafe { from_raw_parts_mut(&mut request as *mut _ as *mut u8, req_sz) };
> +
> +        let mut response_vec: KVec<u8> = KVec::from_elem(0u8, rsp_sz, GFP_KERNEL)?;
> +
> +        let rc = self.spdm_exchange(request_buf, response_vec.as_mut_slice())? as usize;
> +
> +        // The transport must report a length within the buffer we provided.
> +        if rc > response_vec.len() {
> +            pr_err!("Overflowed capabilities response\n");
> +            return Err(EIO);
> +        }
> +        response_vec.truncate(rc);
> +
> +        let response: &NegotiateAlgsRsp = Untrusted::new(response_vec.as_slice()).validate()?;
> +
> +        self.base_asym_alg = u32::from_le(response.base_asym_sel);
> +        self.base_hash_alg = u32::from_le(response.base_hash_sel);
> +        self.meas_hash_alg = u32::from_le(response.measurement_hash_algo);
> +
> +        if self.base_asym_alg & SPDM_ASYM_ALGOS == 0 || self.base_hash_alg & SPDM_HASH_ALGOS == 0 {
> +            pr_err!("No common supported algorithms\n");
> +            return Err(EPROTO);
> +        }
> +
> +        // /* Responder shall select exactly 1 alg (SPDM 1.0.0 table 14) */
> +        if self.base_asym_alg.count_ones() != 1
> +            || self.base_hash_alg.count_ones() != 1
> +            || self.meas_hash_alg.count_ones() != 1

Hi Alistair,

As per the SPDM spec v1.4.0 Table 25 (ALGORITHMS response message
format), description of the field 'MeasurementHashAlgo' states "If the
Responder supports measurements (MEAS_CAP=01b or MEAS_CAP=10b in its
CAPABILITIES response) and if MeasurementSpecificationSel is non-zero,
then exactly one bit in this bit field shall be set. Otherwise, the
Responder shall set this field to 0".

Currently, the code unconditionally checks for exactly one bit. If a
responder does not support measurements, it will legitimately set this
field to 0, which causes the current check to incorrectly fail.

A change somewhat similar to the diff shown below might help here:


              return Err(EPROTO);
          }

+        let meas_hash_valid = if self.rsp_caps & SPDM_MEAS_CAP != 0
+            && response.measurement_specification_sel != 0
+        {
+            self.meas_hash_alg.count_ones() == 1
+        } else {
+            self.meas_hash_alg == 0
+        };
+
          // /* Responder shall select exactly 1 alg (SPDM 1.0.0 table 
14) */
          if self.base_asym_alg.count_ones() != 1
              || self.base_hash_alg.count_ones() != 1
-            || self.meas_hash_alg.count_ones() != 1
+            || !meas_hash_valid
              || response.ext_asym_sel_count != 0
              || response.ext_hash_sel_count != 0
              || response.param1 > request.param1

Regards,
Aksh Garg

> +            || response.ext_asym_sel_count != 0
> +            || response.ext_hash_sel_count != 0
> +            || response.param1 > request.param1
> +            || response.other_params_sel != request.other_params_support
> +        {
> +            pr_err!("Malformed algorithms response\n");
> +            return Err(EPROTO);
> +        }
> +
> +        self.update_response_algs()?;
> +
> +        Ok(())
> +    }