* [PATCH RFT v6 2/9] selftests: Provide helper header for shadow stack testing
From: Mark Brown @ 2024-06-23 11:23 UTC (permalink / raw)
To: Rick P. Edgecombe, Deepak Gupta, Szabolcs Nagy, H.J. Lu,
Florian Weimer, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, x86, H. Peter Anvin, Peter Zijlstra, Juri Lelli,
Vincent Guittot, Dietmar Eggemann, Steven Rostedt, Ben Segall,
Mel Gorman, Daniel Bristot de Oliveira, Valentin Schneider,
Christian Brauner, Shuah Khan
Cc: linux-kernel, Catalin Marinas, Will Deacon, jannh, bsegall,
linux-kselftest, linux-api, Mark Brown, Kees Cook
In-Reply-To: <20240623-clone3-shadow-stack-v6-0-9ee7783b1fb9@kernel.org>
While almost all users of shadow stacks should be relying on the dynamic
linker and libc to enable the feature there are several low level test
programs where it is useful to enable without any libc support, allowing
testing without full system enablement. This low level testing is helpful
during bringup of the support itself, and also in enabling coverage by
automated testing without needing all system components in the target root
filesystems to have enablement.
Provide a header with helpers for this purpose, intended for use only by
test programs directly exercising shadow stack interfaces.
Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
tools/testing/selftests/ksft_shstk.h | 63 ++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)
diff --git a/tools/testing/selftests/ksft_shstk.h b/tools/testing/selftests/ksft_shstk.h
new file mode 100644
index 000000000000..85d0747c1802
--- /dev/null
+++ b/tools/testing/selftests/ksft_shstk.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Helpers for shadow stack enablement, this is intended to only be
+ * used by low level test programs directly exercising interfaces for
+ * working with shadow stacks.
+ *
+ * Copyright (C) 2024 ARM Ltd.
+ */
+
+#ifndef __KSFT_SHSTK_H
+#define __KSFT_SHSTK_H
+
+#include <asm/mman.h>
+
+/* This is currently only defined for x86 */
+#ifndef SHADOW_STACK_SET_TOKEN
+#define SHADOW_STACK_SET_TOKEN (1ULL << 0)
+#endif
+
+static bool shadow_stack_enabled;
+
+#ifdef __x86_64__
+#define ARCH_SHSTK_ENABLE 0x5001
+#define ARCH_SHSTK_SHSTK (1ULL << 0)
+
+#define ARCH_PRCTL(arg1, arg2) \
+({ \
+ long _ret; \
+ register long _num asm("eax") = __NR_arch_prctl; \
+ register long _arg1 asm("rdi") = (long)(arg1); \
+ register long _arg2 asm("rsi") = (long)(arg2); \
+ \
+ asm volatile ( \
+ "syscall\n" \
+ : "=a"(_ret) \
+ : "r"(_arg1), "r"(_arg2), \
+ "0"(_num) \
+ : "rcx", "r11", "memory", "cc" \
+ ); \
+ _ret; \
+})
+
+#define ENABLE_SHADOW_STACK
+static inline __attribute__((always_inline)) void enable_shadow_stack(void)
+{
+ int ret = ARCH_PRCTL(ARCH_SHSTK_ENABLE, ARCH_SHSTK_SHSTK);
+ if (ret == 0)
+ shadow_stack_enabled = true;
+}
+
+#endif
+
+#ifndef __NR_map_shadow_stack
+#define __NR_map_shadow_stack 453
+#endif
+
+#ifndef ENABLE_SHADOW_STACK
+static inline void enable_shadow_stack(void) { }
+#endif
+
+#endif
+
+
--
2.39.2
^ permalink raw reply related
* [PATCH RFT v6 1/9] Documentation: userspace-api: Add shadow stack API documentation
From: Mark Brown @ 2024-06-23 11:23 UTC (permalink / raw)
To: Rick P. Edgecombe, Deepak Gupta, Szabolcs Nagy, H.J. Lu,
Florian Weimer, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, x86, H. Peter Anvin, Peter Zijlstra, Juri Lelli,
Vincent Guittot, Dietmar Eggemann, Steven Rostedt, Ben Segall,
Mel Gorman, Daniel Bristot de Oliveira, Valentin Schneider,
Christian Brauner, Shuah Khan
Cc: linux-kernel, Catalin Marinas, Will Deacon, jannh, bsegall,
linux-kselftest, linux-api, Mark Brown, Kees Cook
In-Reply-To: <20240623-clone3-shadow-stack-v6-0-9ee7783b1fb9@kernel.org>
There are a number of architectures with shadow stack features which we are
presenting to userspace with as consistent an API as we can (though there
are some architecture specifics). Especially given that there are some
important considerations for userspace code interacting directly with the
feature let's provide some documentation covering the common aspects.
Signed-off-by: Mark Brown <broonie@kernel.org>
---
Documentation/userspace-api/index.rst | 1 +
Documentation/userspace-api/shadow_stack.rst | 41 ++++++++++++++++++++++++++++
2 files changed, 42 insertions(+)
diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst
index 5926115ec0ed..d60a6dc0cbcf 100644
--- a/Documentation/userspace-api/index.rst
+++ b/Documentation/userspace-api/index.rst
@@ -59,6 +59,7 @@ Everything else
ELF
netlink/index
+ shadow_stack
sysfs-platform_profile
vduse
futex2
diff --git a/Documentation/userspace-api/shadow_stack.rst b/Documentation/userspace-api/shadow_stack.rst
new file mode 100644
index 000000000000..c576ad3d7ec1
--- /dev/null
+++ b/Documentation/userspace-api/shadow_stack.rst
@@ -0,0 +1,41 @@
+=============
+Shadow Stacks
+=============
+
+Introduction
+============
+
+Several architectures have features which provide backward edge
+control flow protection through a hardware maintained stack, only
+writeable by userspace through very limited operations. This feature
+is referred to as shadow stacks on Linux, on x86 it is part of Intel
+Control Enforcement Technology (CET), on arm64 it is Guarded Control
+Stacks feature (FEAT_GCS) and for RISC-V it is the Zicfiss extension.
+It is expected that this feature will normally be managed by the
+system dynamic linker and libc in ways broadly transparent to
+application code, this document covers interfaces and considerations.
+
+
+Enabling
+========
+
+Shadow stacks default to disabled when a userspace process is
+executed, they can be enabled for the current thread with a syscall:
+
+ - For x86 the ARCH_SHSTK_ENABLE arch_prctl()
+
+It is expected that this will normally be done by the dynamic linker.
+Any new threads created by a thread with shadow stacks enabled will
+themselves have shadow stacks enabled.
+
+
+Enablement considerations
+=========================
+
+- Returning from the function that enables shadow stacks without first
+ disabling them will cause a shadow stack exception. This includes
+ any syscall wrapper or other library functions, the syscall will need
+ to be inlined.
+- A lock feature allows userspace to prevent disabling of shadow stacks.
+- Those that change the stack context like longjmp() or use of ucontext
+ changes on signal return will need support from libc.
--
2.39.2
^ permalink raw reply related
* [PATCH RFT v6 0/9] fork: Support shadow stacks in clone3()
From: Mark Brown @ 2024-06-23 11:23 UTC (permalink / raw)
To: Rick P. Edgecombe, Deepak Gupta, Szabolcs Nagy, H.J. Lu,
Florian Weimer, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, x86, H. Peter Anvin, Peter Zijlstra, Juri Lelli,
Vincent Guittot, Dietmar Eggemann, Steven Rostedt, Ben Segall,
Mel Gorman, Daniel Bristot de Oliveira, Valentin Schneider,
Christian Brauner, Shuah Khan
Cc: linux-kernel, Catalin Marinas, Will Deacon, jannh, bsegall,
linux-kselftest, linux-api, Mark Brown, Kees Cook,
David Hildenbrand
The kernel has recently added support for shadow stacks, currently
x86 only using their CET feature but both arm64 and RISC-V have
equivalent features (GCS and Zicfiss respectively), I am actively
working on GCS[1]. With shadow stacks the hardware maintains an
additional stack containing only the return addresses for branch
instructions which is not generally writeable by userspace and ensures
that any returns are to the recorded addresses. This provides some
protection against ROP attacks and making it easier to collect call
stacks. These shadow stacks are allocated in the address space of the
userspace process.
Our API for shadow stacks does not currently offer userspace any
flexiblity for managing the allocation of shadow stacks for newly
created threads, instead the kernel allocates a new shadow stack with
the same size as the normal stack whenever a thread is created with the
feature enabled. The stacks allocated in this way are freed by the
kernel when the thread exits or shadow stacks are disabled for the
thread. This lack of flexibility and control isn't ideal, in the vast
majority of cases the shadow stack will be over allocated and the
implicit allocation and deallocation is not consistent with other
interfaces. As far as I can tell the interface is done in this manner
mainly because the shadow stack patches were in development since before
clone3() was implemented.
Since clone3() is readily extensible let's add support for specifying a
shadow stack when creating a new thread or process in a similar manner
to how the normal stack is specified, keeping the current implicit
allocation behaviour if one is not specified either with clone3() or
through the use of clone(). The user must provide a shadow stack
address and size, this must point to memory mapped for use as a shadow
stackby map_shadow_stack() with a shadow stack token at the top of the
stack.
Please note that the x86 portions of this code are build tested only, I
don't appear to have a system that can run CET avaible to me, I have
done testing with an integration into my pending work for GCS. There is
some possibility that the arm64 implementation may require the use of
clone3() and explicit userspace allocation of shadow stacks, this is
still under discussion.
Please further note that the token consumption done by clone3() is not
currently implemented in an atomic fashion, Rick indicated that he would
look into fixing this if people are OK with the implementation.
A new architecture feature Kconfig option for shadow stacks is added as
here, this was suggested as part of the review comments for the arm64
GCS series and since we need to detect if shadow stacks are supported it
seemed sensible to roll it in here.
[1] https://lore.kernel.org/r/20231009-arm64-gcs-v6-0-78e55deaa4dd@kernel.org/
Signed-off-by: Mark Brown <broonie@kernel.org>
---
Changes in v6:
- Rebase onto v6.10-rc3.
- Ensure we don't try to free the parent shadow stack in error paths of
x86 arch code.
- Spelling fixes in userspace API document.
- Additional cleanups and improvements to the clone3() tests to support
the shadow stack tests.
- Link to v5: https://lore.kernel.org/r/20240203-clone3-shadow-stack-v5-0-322c69598e4b@kernel.org
Changes in v5:
- Rebase onto v6.8-rc2.
- Rework ABI to have the user allocate the shadow stack memory with
map_shadow_stack() and a token.
- Force inlining of the x86 shadow stack enablement.
- Move shadow stack enablement out into a shared header for reuse by
other tests.
- Link to v4: https://lore.kernel.org/r/20231128-clone3-shadow-stack-v4-0-8b28ffe4f676@kernel.org
Changes in v4:
- Formatting changes.
- Use a define for minimum shadow stack size and move some basic
validation to fork.c.
- Link to v3: https://lore.kernel.org/r/20231120-clone3-shadow-stack-v3-0-a7b8ed3e2acc@kernel.org
Changes in v3:
- Rebase onto v6.7-rc2.
- Remove stale shadow_stack in internal kargs.
- If a shadow stack is specified unconditionally use it regardless of
CLONE_ parameters.
- Force enable shadow stacks in the selftest.
- Update changelogs for RISC-V feature rename.
- Link to v2: https://lore.kernel.org/r/20231114-clone3-shadow-stack-v2-0-b613f8681155@kernel.org
Changes in v2:
- Rebase onto v6.7-rc1.
- Remove ability to provide preallocated shadow stack, just specify the
desired size.
- Link to v1: https://lore.kernel.org/r/20231023-clone3-shadow-stack-v1-0-d867d0b5d4d0@kernel.org
---
Mark Brown (9):
Documentation: userspace-api: Add shadow stack API documentation
selftests: Provide helper header for shadow stack testing
mm: Introduce ARCH_HAS_USER_SHADOW_STACK
fork: Add shadow stack support to clone3()
selftests/clone3: Remove redundant flushes of output streams
selftests/clone3: Factor more of main loop into test_clone3()
selftests/clone3: Explicitly handle child exits due to signals
selftests/clone3: Allow tests to flag if -E2BIG is a valid error code
selftests/clone3: Test shadow stack support
Documentation/userspace-api/index.rst | 1 +
Documentation/userspace-api/shadow_stack.rst | 41 ++++
arch/x86/Kconfig | 1 +
arch/x86/include/asm/shstk.h | 11 +-
arch/x86/kernel/process.c | 2 +-
arch/x86/kernel/shstk.c | 104 +++++++---
fs/proc/task_mmu.c | 2 +-
include/linux/mm.h | 2 +-
include/linux/sched/task.h | 13 ++
include/uapi/linux/sched.h | 13 +-
kernel/fork.c | 76 ++++++--
mm/Kconfig | 6 +
tools/testing/selftests/clone3/clone3.c | 225 ++++++++++++++++++----
tools/testing/selftests/clone3/clone3_selftests.h | 40 +++-
tools/testing/selftests/ksft_shstk.h | 63 ++++++
15 files changed, 512 insertions(+), 88 deletions(-)
---
base-commit: 83a7eefedc9b56fe7bfeff13b6c7356688ffa670
change-id: 20231019-clone3-shadow-stack-15d40d2bf536
Best regards,
--
Mark Brown <broonie@kernel.org>
^ permalink raw reply
* Re: [PATCH RFC] LSM, net: Add SO_PEERCONTEXT for peer LSM data
From: Casey Schaufler @ 2024-06-21 22:00 UTC (permalink / raw)
To: Paul Moore
Cc: LSM List, netdev, linux-api, Linux kernel mailing list,
Casey Schaufler
In-Reply-To: <CAHC9VhRjbWuFeprjNP3r7tU27cW6bEZytWq-3XTjzoN7Ki-zzQ@mail.gmail.com>
On 6/21/2024 12:41 PM, Paul Moore wrote:
> On Fri, Jun 21, 2024 at 12:06 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>> On 6/20/2024 2:05 PM, Paul Moore wrote:
>>> On May 13, 2024 Casey Schaufler <casey@schaufler-ca.com> wrote:
> ..
>
>>>> +/**
>>>> + * security_socket_getpeerctx_stream() - Get the remote peer label
>>>> + * @sock: socket
>>>> + * @optval: destination buffer
>>>> + * @optlen: size of peer label copied into the buffer
>>>> + * @len: maximum size of the destination buffer
>>>> + *
>>>> + * This hook allows the security module to provide peer socket security state
>>>> + * for unix or connected tcp sockets to userspace via getsockopt
>>>> + * SO_GETPEERCONTEXT. For tcp sockets this can be meaningful if the socket
>>>> + * is associated with an ipsec SA.
>>>> + *
>>>> + * Return: Returns 0 if all is well, otherwise, typical getsockopt return
>>>> + * values.
>>>> + */
>>>> +int security_socket_getpeerctx_stream(struct socket *sock, sockptr_t optval,
>>>> + sockptr_t optlen, unsigned int len)
>>>> +{
>>>> + struct security_hook_list *hp;
>>>> +
>>>> + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeerctx_stream,
>>>> + list)
>>>> + return hp->hook.socket_getpeerctx_stream(sock, optval, optlen,
>>>> + len);
>>>> +
>>>> + return LSM_RET_DEFAULT(socket_getpeerctx_stream);
>>>> +}
>>> Don't we need the same magic that we have in security_getselfattr() to
>>> handle the multi-LSM case?
>> Yes. I would like to move this ahead independently of the multi-LSM support.
>> Putting the multi-LSM magic in is unnecessary and rather pointless until then.
> Starting with the LSM syscalls, I want any new user visible API that
> can support multiple LSMs to have support for multiple LSMs. Yes, the
> setselfattr API doesn't support multiple LSMs, but that is because we
> agreed there was never going to be a way to safely support that usage.
> In this particular case, that same argument does not apply, we could
> have multiple LSMs returning a socket's network peer information (even
> if we don't currently see that), so let's make sure our API supports
> it from the start.
OK. I'll put that in v2 as well.
>
> Unrelated to the above, it would also be good to datagram support as a
> patch 2/2 thing in a future version of this patchset. Please be
> careful not to carry over the mistakes we made with SCM_SECURITY (see
> the GH discussion linked below).
That's "in my queue". I didn't want to spend time on it until I got
feedback on this one.
>
> * https://github.com/SELinuxProject/selinux-kernel/issues/24
>
^ permalink raw reply
* Re: [PATCH RFC] LSM, net: Add SO_PEERCONTEXT for peer LSM data
From: Paul Moore @ 2024-06-21 19:41 UTC (permalink / raw)
To: Casey Schaufler; +Cc: LSM List, netdev, linux-api, Linux kernel mailing list
In-Reply-To: <c59a4954-913b-4672-b502-21aa683d7cdb@schaufler-ca.com>
On Fri, Jun 21, 2024 at 12:06 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 6/20/2024 2:05 PM, Paul Moore wrote:
> > On May 13, 2024 Casey Schaufler <casey@schaufler-ca.com> wrote:
...
> >> +/**
> >> + * security_socket_getpeerctx_stream() - Get the remote peer label
> >> + * @sock: socket
> >> + * @optval: destination buffer
> >> + * @optlen: size of peer label copied into the buffer
> >> + * @len: maximum size of the destination buffer
> >> + *
> >> + * This hook allows the security module to provide peer socket security state
> >> + * for unix or connected tcp sockets to userspace via getsockopt
> >> + * SO_GETPEERCONTEXT. For tcp sockets this can be meaningful if the socket
> >> + * is associated with an ipsec SA.
> >> + *
> >> + * Return: Returns 0 if all is well, otherwise, typical getsockopt return
> >> + * values.
> >> + */
> >> +int security_socket_getpeerctx_stream(struct socket *sock, sockptr_t optval,
> >> + sockptr_t optlen, unsigned int len)
> >> +{
> >> + struct security_hook_list *hp;
> >> +
> >> + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeerctx_stream,
> >> + list)
> >> + return hp->hook.socket_getpeerctx_stream(sock, optval, optlen,
> >> + len);
> >> +
> >> + return LSM_RET_DEFAULT(socket_getpeerctx_stream);
> >> +}
> >
> > Don't we need the same magic that we have in security_getselfattr() to
> > handle the multi-LSM case?
>
> Yes. I would like to move this ahead independently of the multi-LSM support.
> Putting the multi-LSM magic in is unnecessary and rather pointless until then.
Starting with the LSM syscalls, I want any new user visible API that
can support multiple LSMs to have support for multiple LSMs. Yes, the
setselfattr API doesn't support multiple LSMs, but that is because we
agreed there was never going to be a way to safely support that usage.
In this particular case, that same argument does not apply, we could
have multiple LSMs returning a socket's network peer information (even
if we don't currently see that), so let's make sure our API supports
it from the start.
Unrelated to the above, it would also be good to datagram support as a
patch 2/2 thing in a future version of this patchset. Please be
careful not to carry over the mistakes we made with SCM_SECURITY (see
the GH discussion linked below).
* https://github.com/SELinuxProject/selinux-kernel/issues/24
--
paul-moore.com
^ permalink raw reply
* Re: [PATCH RFC] LSM, net: Add SO_PEERCONTEXT for peer LSM data
From: Casey Schaufler @ 2024-06-21 16:06 UTC (permalink / raw)
To: Paul Moore, LSM List, netdev, linux-api,
Linux kernel mailing list, Casey Schaufler
In-Reply-To: <83ef6981a29c441b58b525e9292c866a@paul-moore.com>
On 6/20/2024 2:05 PM, Paul Moore wrote:
> On May 13, 2024 Casey Schaufler <casey@schaufler-ca.com> wrote:
>> We recently introduced system calls to access process attributes that
>> are used by Linux Security Modules (LSM). An important aspect of these
>> system calls is that they provide the LSM attribute data in a format
>> that identifies the LSM to which the data applies. Another aspect is that
>> it can be used to provide multiple instances of the attribute for the
>> case where more than one LSM supplies the attribute.
>>
>> We wish to take advantage of this format for data about network peers.
>> The existing mechanism, SO_PEERSEC, provides peer security data as a
>> text string. This is sufficient when the LSM providing the information
>> is known by the user of SO_PEERSEC, and there is only one LSM providing
>> the information. It fails, however, if the user does not know which
>> LSM is providing the information.
>>
>> Discussions about extending SO_PEERSEC to accomodate either the new
> Spelling nitpick -> "accommodate" :)
Thanks.
>> format or some other encoding scheme invariably lead to the conclusion
>> that doing so would lead to tears. Hence, we introduce SO_PEERCONTEXT
>> which uses the same API data as the LSM system calls.
>>
>> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
>> ---
>> arch/alpha/include/uapi/asm/socket.h | 1 +
>> arch/mips/include/uapi/asm/socket.h | 1 +
>> arch/parisc/include/uapi/asm/socket.h | 1 +
>> arch/sparc/include/uapi/asm/socket.h | 1 +
>> include/linux/lsm_hook_defs.h | 2 +
>> include/linux/security.h | 18 ++++++++
>> include/uapi/asm-generic/socket.h | 1 +
>> net/core/sock.c | 4 ++
>> security/apparmor/lsm.c | 39 ++++++++++++++++
>> security/security.c | 86 +++++++++++++++++++++++++++++++++++
>> security/selinux/hooks.c | 35 ++++++++++++++
>> security/smack/smack_lsm.c | 25 ++++++++++
>> 12 files changed, 214 insertions(+)
> ..
>
>> diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
>> index 8ce8a39a1e5f..e0166ff53670 100644
>> --- a/include/uapi/asm-generic/socket.h
>> +++ b/include/uapi/asm-generic/socket.h
>> @@ -134,6 +134,7 @@
>>
>> #define SO_PASSPIDFD 76
>> #define SO_PEERPIDFD 77
>> +#define SO_PEERCONTEXT 78
> Bikeshed time ... how about SO_PEERLSMCTX since we are returning a
> lsm_ctx struct?
Sure.
>> diff --git a/security/security.c b/security/security.c
>> index e387614cb054..fd4919c28e8f 100644
>> --- a/security/security.c
>> +++ b/security/security.c
>> @@ -874,6 +874,64 @@ int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, u32 *uctx_len,
>> return rc;
>> }
>>
>> +/**
>> + * lsm_fill_socket_ctx - Fill a socket lsm_ctx structure
>> + * @optval: a socket LSM context to be filled
>> + * @optlen: uctx size
> "@optlen: @optval size"
Thank you.
>> + * @val: the new LSM context value
>> + * @val_len: the size of the new LSM context value
>> + * @id: LSM id
>> + * @flags: LSM defined flags
>> + *
>> + * Fill all of the fields in a lsm_ctx structure. If @optval is NULL
>> + * simply calculate the required size to output via @optlen and return
>> + * success.
>> + *
>> + * Returns 0 on success, -E2BIG if userspace buffer is not large enough,
>> + * -EFAULT on a copyout error, -ENOMEM if memory can't be allocated.
>> + */
>> +int lsm_fill_socket_ctx(sockptr_t optval, sockptr_t optlen, void *val,
>> + size_t val_len, u64 id, u64 flags)
>> +{
>> + struct lsm_ctx *nctx = NULL;
>> + unsigned int nctx_len;
>> + int loptlen;
> u32?
Probably. I'll revise in line with your comment below.
>> + int rc = 0;
>> +
>> + if (copy_from_sockptr(&loptlen, optlen, sizeof(int)))
>> + return -EFAULT;
> It seems the current guidance prefers copy_safe_from_sockptr(), see
> the note in include/linux/sockptr.h.
Always a good idea to follow guidance.
>> + nctx_len = ALIGN(struct_size(nctx, ctx, val_len), sizeof(void *));
>> + if (nctx_len > loptlen && !sockptr_is_null(optval))
>> + rc = -E2BIG;
> Why do we care if @optval is NULL or not? We are in a -E2BIG state,
> we're not copying anything into @optval anyway. In fact, why are we
> doing the @rc check below? Do it here like we do in lsm_fill_user_ctx().
>
> if (nctx_len > loptlen) {
> rc = -E2BIG;
> goto out;
> }
That's a bit sloppy on my part. I'll clean it up.
>> + /* no buffer - return success/0 and set @uctx_len to the req size */
> "... set @opt_len ... "
Yes.
>> + if (sockptr_is_null(optval) || rc)
>> + goto out;
> Do the @rc check above, not here.
>
>> + nctx = kzalloc(nctx_len, GFP_KERNEL);
>> + if (!nctx) {
>> + rc = -ENOMEM;
>> + goto out;
>> + }
>> + nctx->id = id;
>> + nctx->flags = flags;
>> + nctx->len = nctx_len;
>> + nctx->ctx_len = val_len;
>> + memcpy(nctx->ctx, val, val_len);
>> +
>> + if (copy_to_sockptr(optval, nctx, nctx_len))
>> + rc = -EFAULT;
> This is always going to copy to the start of @optval which means we
> are going to keep overwriting previous values in the multi-LSM case.
The multiple LSM case isn't handled in this version. I don't want this
patch to depend on multiple LSM support.
> I think we likely want copy_to_sockptr_offset(), or similar. See my
> comment in security_socket_getpeerctx_stream().
>
>> + kfree(nctx);
>> +out:
>> + if (copy_to_sockptr(optlen, &nctx_len, sizeof(int)))
>> + rc = -EFAULT;
>> +
>> + return rc;
>> +}
>> +
>> +
>> /*
>> * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
>> * can be accessed with:
>> @@ -4743,6 +4801,34 @@ int security_socket_getpeersec_stream(struct socket *sock, sockptr_t optval,
>> return LSM_RET_DEFAULT(socket_getpeersec_stream);
>> }
>>
>> +/**
>> + * security_socket_getpeerctx_stream() - Get the remote peer label
>> + * @sock: socket
>> + * @optval: destination buffer
>> + * @optlen: size of peer label copied into the buffer
>> + * @len: maximum size of the destination buffer
>> + *
>> + * This hook allows the security module to provide peer socket security state
>> + * for unix or connected tcp sockets to userspace via getsockopt
>> + * SO_GETPEERCONTEXT. For tcp sockets this can be meaningful if the socket
>> + * is associated with an ipsec SA.
>> + *
>> + * Return: Returns 0 if all is well, otherwise, typical getsockopt return
>> + * values.
>> + */
>> +int security_socket_getpeerctx_stream(struct socket *sock, sockptr_t optval,
>> + sockptr_t optlen, unsigned int len)
>> +{
>> + struct security_hook_list *hp;
>> +
>> + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeerctx_stream,
>> + list)
>> + return hp->hook.socket_getpeerctx_stream(sock, optval, optlen,
>> + len);
>> +
>> + return LSM_RET_DEFAULT(socket_getpeerctx_stream);
>> +}
> Don't we need the same magic that we have in security_getselfattr() to
> handle the multi-LSM case?
Yes. I would like to move this ahead independently of the multi-LSM support.
Putting the multi-LSM magic in is unnecessary and rather pointless until then.
> --
> paul-moore.com
Thank you for the review. Expect v2 before very long.
^ permalink raw reply
* Re: [PATCH v2] platform/x86: asus-wmi: support the disable camera LED on F10 of Zenbook 2023
From: Luke Jones @ 2024-06-21 9:27 UTC (permalink / raw)
To: Devin Bayer, corentin.chary
Cc: Hans de Goede, platform-driver-x86, linux-kernel, linux-api,
Ilpo Järvinen
In-Reply-To: <20240621085745.233107-1-dev@doubly.so>
On Fri, 21 Jun 2024, at 8:57 PM, Devin Bayer wrote:
> Adds a sysfs entry for the LED on F10 above the crossed out camera icon on 2023 Zenbooks.
>
> v2
> - Changed name from `platform::camera` to `asus::camera`
> - Separated patch from patchset
>
> v1
> - https://lore.kernel.org/platform-driver-x86/20240620082223.20178-1-dev@doubly.so/
>
> Signed-off-by: Devin Bayer <dev@doubly.so>
> ---
> drivers/platform/x86/asus-wmi.c | 36 ++++++++++++++++++++++
> include/linux/platform_data/x86/asus-wmi.h | 2 ++
> 2 files changed, 38 insertions(+)
>
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 3f07bbf809ef..20b7ed6a27b5 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -73,6 +73,7 @@ module_param(fnlock_default, bool, 0444);
> #define NOTIFY_LID_FLIP_ROG 0xbd
>
> #define ASUS_WMI_FNLOCK_BIOS_DISABLED BIT(0)
> +#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
>
> #define ASUS_MID_FAN_DESC "mid_fan"
> #define ASUS_GPU_FAN_DESC "gpu_fan"
> @@ -227,6 +228,7 @@ struct asus_wmi {
> struct led_classdev lightbar_led;
> int lightbar_led_wk;
> struct led_classdev micmute_led;
> + struct led_classdev camera_led;
> struct workqueue_struct *led_workqueue;
> struct work_struct tpd_led_work;
> struct work_struct wlan_led_work;
> @@ -1533,6 +1535,27 @@ static int micmute_led_set(struct led_classdev *led_cdev,
> return err < 0 ? err : 0;
> }
>
> +static enum led_brightness camera_led_get(struct led_classdev *led_cdev)
> +{
> + struct asus_wmi *asus;
> + u32 result;
> +
> + asus = container_of(led_cdev, struct asus_wmi, camera_led);
> + asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_CAMERA_LED, &result);
> +
> + return result & ASUS_WMI_DSTS_BRIGHTNESS_MASK;
> +}
> +
> +static int camera_led_set(struct led_classdev *led_cdev,
> + enum led_brightness brightness)
> +{
> + int state = brightness != LED_OFF;
> + int err;
> +
> + err = asus_wmi_set_devstate(ASUS_WMI_DEVID_CAMERA_LED, state, NULL);
> + return err < 0 ? err : 0;
> +}
> +
> static void asus_wmi_led_exit(struct asus_wmi *asus)
> {
> led_classdev_unregister(&asus->kbd_led);
> @@ -1540,6 +1563,7 @@ static void asus_wmi_led_exit(struct asus_wmi *asus)
> led_classdev_unregister(&asus->wlan_led);
> led_classdev_unregister(&asus->lightbar_led);
> led_classdev_unregister(&asus->micmute_led);
> + led_classdev_unregister(&asus->camera_led);
>
> if (asus->led_workqueue)
> destroy_workqueue(asus->led_workqueue);
> @@ -1631,6 +1655,18 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
> goto error;
> }
>
> + if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CAMERA_LED)) {
> + asus->camera_led.name = "asus::camera";
> + asus->camera_led.max_brightness = 1;
> + asus->camera_led.brightness_get = camera_led_get;
> + asus->camera_led.brightness_set_blocking = camera_led_set;
> +
> + rv = led_classdev_register(&asus->platform_device->dev,
> + &asus->camera_led);
> + if (rv)
> + goto error;
> + }
> +
> error:
> if (rv)
> asus_wmi_led_exit(asus);
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index ab1c7deff118..fb0b00f7d292 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -50,6 +50,8 @@
> #define ASUS_WMI_DEVID_LED5 0x00020015
> #define ASUS_WMI_DEVID_LED6 0x00020016
> #define ASUS_WMI_DEVID_MICMUTE_LED 0x00040017
> +#define ASUS_WMI_DEVID_CAMERA_LED_NEG 0x00060078
> +#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
>
> /* Backlight and Brightness */
> #define ASUS_WMI_DEVID_ALS_ENABLE 0x00050001 /* Ambient Light Sensor */
> --
> 2.45.2
>
If Hans and Ilpo have no other comments regarding the written C code:
Signed-off-by: Luke D. Jones <luke@ljones.dev>
^ permalink raw reply
* Re: [PATCH 1/2] platform/x86: asus-wmi: support camera disable LED
From: Luke Jones @ 2024-06-21 9:25 UTC (permalink / raw)
To: Devin Bayer, corentin.chary
Cc: Hans de Goede, platform-driver-x86, linux-kernel, linux-api,
Ilpo Järvinen
In-Reply-To: <a18c8b3a-90b0-47a7-aff6-a289ecddc2c0@doubly.so>
On Fri, 21 Jun 2024, at 7:50 PM, Devin Bayer wrote:
>
> Thanks for the review, Luke.
>
> On 20/06/2024 23.40, Luke Jones wrote:
> >>
> >> + if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CAMERA_LED)) {
> >> + asus->camera_led.name = "platform::camera";
> >
> > What do other devices label their camera LED as? The one I could find appears to use `<vendor>::camera`. So maybe `asus::camera` would be better? This also keeps in line with `asus::kbd_backlight`.
>
> I reasoned it would be better to keep the name generic is so out of the
> box desktops could toggle the camera and the LED when KEY_CAMERA is
> pressed, just like with micmute and mute.
This might be true if one relies solely on the filesystem path, which in any case is a bad move and likely to cause the moon to drift away from earth eventually. Most Linux software will use the udev libraries available to filter devices according to any amount of criteria (and if they are not they *really should* - udev is pretty powerful and freeing.
I've tried finding prior art again and there's just not a lot to go on. ".name = "platform" shows very little except a few micmute labels. "::cam" gets one entry. So my guess is this is still a very new thing or it's not important enough to be used..
In any case looking at the rest of the possible LED entries, mostly those following keyboard, the last part of the name being sensible is what counts the most (e.g "scrolllock", "camera"). This might be setting a precedent, and if so I'd be happy with "::camera" in the LED class conveying expectations well enough.
^ permalink raw reply
* [PATCH v2] platform/x86: asus-wmi: support the disable camera LED on F10 of Zenbook 2023
From: Devin Bayer @ 2024-06-21 8:57 UTC (permalink / raw)
To: corentin.chary, luke
Cc: hdegoede, platform-driver-x86, linux-kernel, linux-api,
ilpo.jarvinen, Devin Bayer
Adds a sysfs entry for the LED on F10 above the crossed out camera icon on 2023 Zenbooks.
v2
- Changed name from `platform::camera` to `asus::camera`
- Separated patch from patchset
v1
- https://lore.kernel.org/platform-driver-x86/20240620082223.20178-1-dev@doubly.so/
Signed-off-by: Devin Bayer <dev@doubly.so>
---
drivers/platform/x86/asus-wmi.c | 36 ++++++++++++++++++++++
include/linux/platform_data/x86/asus-wmi.h | 2 ++
2 files changed, 38 insertions(+)
diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 3f07bbf809ef..20b7ed6a27b5 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -73,6 +73,7 @@ module_param(fnlock_default, bool, 0444);
#define NOTIFY_LID_FLIP_ROG 0xbd
#define ASUS_WMI_FNLOCK_BIOS_DISABLED BIT(0)
+#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
#define ASUS_MID_FAN_DESC "mid_fan"
#define ASUS_GPU_FAN_DESC "gpu_fan"
@@ -227,6 +228,7 @@ struct asus_wmi {
struct led_classdev lightbar_led;
int lightbar_led_wk;
struct led_classdev micmute_led;
+ struct led_classdev camera_led;
struct workqueue_struct *led_workqueue;
struct work_struct tpd_led_work;
struct work_struct wlan_led_work;
@@ -1533,6 +1535,27 @@ static int micmute_led_set(struct led_classdev *led_cdev,
return err < 0 ? err : 0;
}
+static enum led_brightness camera_led_get(struct led_classdev *led_cdev)
+{
+ struct asus_wmi *asus;
+ u32 result;
+
+ asus = container_of(led_cdev, struct asus_wmi, camera_led);
+ asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_CAMERA_LED, &result);
+
+ return result & ASUS_WMI_DSTS_BRIGHTNESS_MASK;
+}
+
+static int camera_led_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ int state = brightness != LED_OFF;
+ int err;
+
+ err = asus_wmi_set_devstate(ASUS_WMI_DEVID_CAMERA_LED, state, NULL);
+ return err < 0 ? err : 0;
+}
+
static void asus_wmi_led_exit(struct asus_wmi *asus)
{
led_classdev_unregister(&asus->kbd_led);
@@ -1540,6 +1563,7 @@ static void asus_wmi_led_exit(struct asus_wmi *asus)
led_classdev_unregister(&asus->wlan_led);
led_classdev_unregister(&asus->lightbar_led);
led_classdev_unregister(&asus->micmute_led);
+ led_classdev_unregister(&asus->camera_led);
if (asus->led_workqueue)
destroy_workqueue(asus->led_workqueue);
@@ -1631,6 +1655,18 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
goto error;
}
+ if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CAMERA_LED)) {
+ asus->camera_led.name = "asus::camera";
+ asus->camera_led.max_brightness = 1;
+ asus->camera_led.brightness_get = camera_led_get;
+ asus->camera_led.brightness_set_blocking = camera_led_set;
+
+ rv = led_classdev_register(&asus->platform_device->dev,
+ &asus->camera_led);
+ if (rv)
+ goto error;
+ }
+
error:
if (rv)
asus_wmi_led_exit(asus);
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index ab1c7deff118..fb0b00f7d292 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -50,6 +50,8 @@
#define ASUS_WMI_DEVID_LED5 0x00020015
#define ASUS_WMI_DEVID_LED6 0x00020016
#define ASUS_WMI_DEVID_MICMUTE_LED 0x00040017
+#define ASUS_WMI_DEVID_CAMERA_LED_NEG 0x00060078
+#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
/* Backlight and Brightness */
#define ASUS_WMI_DEVID_ALS_ENABLE 0x00050001 /* Ambient Light Sensor */
--
2.45.2
^ permalink raw reply related
* Re: [PATCH 2/2] platform/x86: asus-wmi: support newer fan_boost_mode dev_id
From: Devin Bayer @ 2024-06-21 7:53 UTC (permalink / raw)
To: Luke Jones, corentin.chary
Cc: Hans de Goede, platform-driver-x86, linux-kernel, linux-api,
Ilpo Järvinen
In-Reply-To: <19cb366a-e6d8-4608-98c9-0fad389363ee@app.fastmail.com>
On 20/06/2024 23.17, Luke Jones wrote:
>
>> #define ASUS_WMI_FNLOCK_BIOS_DISABLED BIT(0)
>> -#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
>
> Be careful not to introduce extraneous changes.
Yes, will do.
> Thank you for the work on this. But I must point out that the same 0x00110019 method has already been submitted as a patch to work with the existing "throttle_thermal" functionality, which itself is also tied to platoform_profile class support.
>
> See https://lore.kernel.org/platform-driver-x86/20240609144849.2532-1-mohamed.ghanmi@supcom.tn/T/#mcd18e74676084e21d5c15af84bc08d8c6b375fb9
I see that now.
> If you could submit only the first patch instead please?
I'll followup on this topic in the other thread.
~ Dev
^ permalink raw reply
* Re: [PATCH 1/2] platform/x86: asus-wmi: support camera disable LED
From: Devin Bayer @ 2024-06-21 7:50 UTC (permalink / raw)
To: Luke Jones, corentin.chary
Cc: Hans de Goede, platform-driver-x86, linux-kernel, linux-api,
Ilpo Järvinen
In-Reply-To: <ede8505f-bcf6-403e-bda2-6848cd4ff4c7@app.fastmail.com>
Thanks for the review, Luke.
On 20/06/2024 23.40, Luke Jones wrote:
>>
>> + if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CAMERA_LED)) {
>> + asus->camera_led.name = "platform::camera";
>
> What do other devices label their camera LED as? The one I could find appears to use `<vendor>::camera`. So maybe `asus::camera` would be better? This also keeps in line with `asus::kbd_backlight`.
I reasoned it would be better to keep the name generic is so out of the
box desktops could toggle the camera and the LED when KEY_CAMERA is
pressed, just like with micmute and mute.
But I'll submit a new version with just this patch and the name change.
~ Dev
^ permalink raw reply
* Re: [PATCH 1/2] platform/x86: asus-wmi: support camera disable LED
From: Luke Jones @ 2024-06-20 21:40 UTC (permalink / raw)
To: Devin Bayer, corentin.chary
Cc: Hans de Goede, platform-driver-x86, linux-kernel, linux-api,
Ilpo Järvinen
In-Reply-To: <20240620082223.20178-2-dev@doubly.so>
On Thu, 20 Jun 2024, at 8:22 PM, Devin Bayer wrote:
> Support the LED on F10 above the crossed out camera icon.
>
> Signed-off-by: Devin Bayer <dev@doubly.so>
> ---
> drivers/platform/x86/asus-wmi.c | 36 ++++++++++++++++++++++
> include/linux/platform_data/x86/asus-wmi.h | 2 ++
> 2 files changed, 38 insertions(+)
>
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 3f9b6285c9a6..5585f15e7920 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -73,6 +73,7 @@ module_param(fnlock_default, bool, 0444);
> #define NOTIFY_LID_FLIP_ROG 0xbd
>
> #define ASUS_WMI_FNLOCK_BIOS_DISABLED BIT(0)
> +#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
>
> #define ASUS_MID_FAN_DESC "mid_fan"
> #define ASUS_GPU_FAN_DESC "gpu_fan"
> @@ -238,6 +239,7 @@ struct asus_wmi {
> struct led_classdev lightbar_led;
> int lightbar_led_wk;
> struct led_classdev micmute_led;
> + struct led_classdev camera_led;
> struct workqueue_struct *led_workqueue;
> struct work_struct tpd_led_work;
> struct work_struct wlan_led_work;
> @@ -1642,6 +1644,27 @@ static int micmute_led_set(struct led_classdev *led_cdev,
> return err < 0 ? err : 0;
> }
>
> +static enum led_brightness camera_led_get(struct led_classdev *led_cdev)
> +{
> + struct asus_wmi *asus;
> + u32 result;
> +
> + asus = container_of(led_cdev, struct asus_wmi, camera_led);
> + asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_CAMERA_LED, &result);
> +
> + return result & ASUS_WMI_DSTS_BRIGHTNESS_MASK;
> +}
> +
> +static int camera_led_set(struct led_classdev *led_cdev,
> + enum led_brightness brightness)
> +{
> + int state = brightness != LED_OFF;
> + int err;
> +
> + err = asus_wmi_set_devstate(ASUS_WMI_DEVID_CAMERA_LED, state, NULL);
> + return err < 0 ? err : 0;
> +}
> +
> static void asus_wmi_led_exit(struct asus_wmi *asus)
> {
> led_classdev_unregister(&asus->kbd_led);
> @@ -1649,6 +1672,7 @@ static void asus_wmi_led_exit(struct asus_wmi *asus)
> led_classdev_unregister(&asus->wlan_led);
> led_classdev_unregister(&asus->lightbar_led);
> led_classdev_unregister(&asus->micmute_led);
> + led_classdev_unregister(&asus->camera_led);
>
> if (asus->led_workqueue)
> destroy_workqueue(asus->led_workqueue);
> @@ -1740,6 +1764,18 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
> goto error;
> }
>
> + if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CAMERA_LED)) {
> + asus->camera_led.name = "platform::camera";
What do other devices label their camera LED as? The one I could find appears to use `<vendor>::camera`. So maybe `asus::camera` would be better? This also keeps in line with `asus::kbd_backlight`.
> + asus->camera_led.max_brightness = 1;
> + asus->camera_led.brightness_get = camera_led_get;
> + asus->camera_led.brightness_set_blocking = camera_led_set;
> +
> + rv = led_classdev_register(&asus->platform_device->dev,
> + &asus->camera_led);
> + if (rv)
> + goto error;
> + }
> +
> error:
> if (rv)
> asus_wmi_led_exit(asus);
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 3eb5cd6773ad..b3c35e33f1e7 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -50,6 +50,8 @@
> #define ASUS_WMI_DEVID_LED5 0x00020015
> #define ASUS_WMI_DEVID_LED6 0x00020016
> #define ASUS_WMI_DEVID_MICMUTE_LED 0x00040017
> +#define ASUS_WMI_DEVID_CAMERA_LED_NEG 0x00060078
> +#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
>
> /* Backlight and Brightness */
> #define ASUS_WMI_DEVID_ALS_ENABLE 0x00050001 /* Ambient Light Sensor */
> --
> 2.45.2
>
I'll defer final review to Hans and Ilpo to be sure I've not missed anything, otherwise it LGTM pending the one comment above.
^ permalink raw reply
* Re: [PATCH 2/2] platform/x86: asus-wmi: support newer fan_boost_mode dev_id
From: Luke Jones @ 2024-06-20 21:17 UTC (permalink / raw)
To: Devin Bayer, corentin.chary
Cc: Hans de Goede, platform-driver-x86, linux-kernel, linux-api,
Ilpo Järvinen
In-Reply-To: <20240620082223.20178-3-dev@doubly.so>
On Thu, 20 Jun 2024, at 8:22 PM, Devin Bayer wrote:
> Support changing the fan mode (silent, performance, standard). I reused
> the existing fan_boost_mode sysfs entry.
>
> Signed-off-by: Devin Bayer <dev@doubly.so>
> ---
> drivers/platform/x86/asus-wmi.c | 87 ++++++++++++++++++++--
> include/linux/platform_data/x86/asus-wmi.h | 1 +
> 2 files changed, 82 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 5585f15e7920..e27b8f86d57b 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -73,7 +73,6 @@ module_param(fnlock_default, bool, 0444);
> #define NOTIFY_LID_FLIP_ROG 0xbd
>
> #define ASUS_WMI_FNLOCK_BIOS_DISABLED BIT(0)
> -#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
Be careful not to introduce extraneous changes.
>
> #define ASUS_MID_FAN_DESC "mid_fan"
> #define ASUS_GPU_FAN_DESC "gpu_fan"
> @@ -94,6 +93,10 @@ module_param(fnlock_default, bool, 0444);
> #define ASUS_FAN_BOOST_MODE_SILENT_MASK 0x02
> #define ASUS_FAN_BOOST_MODES_MASK 0x03
>
> +#define ASUS_FAN_BOOST_MODE2_NORMAL 0
> +#define ASUS_FAN_BOOST_MODE2_SILENT 1
> +#define ASUS_FAN_BOOST_MODE2_OVERBOOST 2
> +
> #define ASUS_THROTTLE_THERMAL_POLICY_DEFAULT 0
> #define ASUS_THROTTLE_THERMAL_POLICY_OVERBOOST 1
> #define ASUS_THROTTLE_THERMAL_POLICY_SILENT 2
> @@ -268,6 +271,7 @@ struct asus_wmi {
> int agfn_pwm;
>
> bool fan_boost_mode_available;
> + u32 fan_boost_mode_dev_id;
> u8 fan_boost_mode_mask;
> u8 fan_boost_mode;
>
> @@ -3019,14 +3023,14 @@ static int asus_wmi_fan_init(struct asus_wmi *asus)
>
> /* Fan mode *******************************************************************/
>
> -static int fan_boost_mode_check_present(struct asus_wmi *asus)
> +static int fan_boost_mode1_check_present(struct asus_wmi *asus)
> {
> u32 result;
> int err;
>
> - asus->fan_boost_mode_available = false;
> + asus->fan_boost_mode_dev_id = ASUS_WMI_DEVID_FAN_BOOST_MODE;
>
> - err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_FAN_BOOST_MODE,
> + err = asus_wmi_get_devstate(asus, asus->fan_boost_mode_dev_id,
> &result);
> if (err) {
> if (err == -ENODEV)
> @@ -3044,16 +3048,87 @@ static int fan_boost_mode_check_present(struct asus_wmi *asus)
> return 0;
> }
>
> +static int fan_boost_mode2_check_present(struct asus_wmi *asus)
> +{
> + u32 result;
> + int err;
> +
> + asus->fan_boost_mode_mask = ASUS_FAN_BOOST_MODES_MASK;
> + asus->fan_boost_mode_dev_id = ASUS_WMI_DEVID_FAN_BOOST_MODE2;
> +
> + err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_FAN_BOOST_MODE2,
> + &result);
> + if (err) {
> + if (err == -ENODEV)
> + return 0;
> + else
> + return err;
> + }
> +
> + if (! (result & ASUS_WMI_DSTS_PRESENCE_BIT))
> + return 0;
> +
> + asus->fan_boost_mode_available = true;
> +
> + if (result & ASUS_FAN_BOOST_MODE2_SILENT) {
> + asus->fan_boost_mode = ASUS_FAN_BOOST_MODE_SILENT;
> + } else if(result & ASUS_FAN_BOOST_MODE2_OVERBOOST) {
> + asus->fan_boost_mode = ASUS_FAN_BOOST_MODE_OVERBOOST;
> + } else {
> + asus->fan_boost_mode = ASUS_FAN_BOOST_MODE_NORMAL;
> + }
> +
> + return 0;
> +}
> +
> +static int fan_boost_mode_check_present(struct asus_wmi *asus)
> +{
> + int err;
> +
> + asus->fan_boost_mode_available = false;
> +
> + err = fan_boost_mode1_check_present(asus);
> + if (err)
> + return err;
> +
> + if (!asus->fan_boost_mode_available) {
> + err = fan_boost_mode2_check_present(asus);
> + }
> +
> + return err;
> +}
> +
> static int fan_boost_mode_write(struct asus_wmi *asus)
> {
> u32 retval;
> u8 value;
> + u8 hw_value;
> int err;
>
> value = asus->fan_boost_mode;
>
> - pr_info("Set fan boost mode: %u\n", value);
> - err = asus_wmi_set_devstate(ASUS_WMI_DEVID_FAN_BOOST_MODE, value,
> + /* transform userspace values into hardware values */
> + if(asus->fan_boost_mode_dev_id == ASUS_WMI_DEVID_FAN_BOOST_MODE2) {
> + switch(value) {
> + case ASUS_FAN_BOOST_MODE_SILENT:
> + hw_value = ASUS_FAN_BOOST_MODE2_SILENT;
> + break;
> + case ASUS_FAN_BOOST_MODE_OVERBOOST:
> + hw_value = ASUS_FAN_BOOST_MODE2_OVERBOOST;
> + break;
> + case ASUS_FAN_BOOST_MODE_NORMAL:
> + hw_value = ASUS_FAN_BOOST_MODE2_NORMAL;
> + break;
> + default:
> + return -EINVAL;
> +
> + }
> + } else {
> + hw_value = value;
> + }
> +
> + pr_info("Set fan boost mode: user=%u hw=%u\n", value, hw_value);
> + err = asus_wmi_set_devstate(asus->fan_boost_mode_dev_id, hw_value,
> &retval);
>
> sysfs_notify(&asus->platform_device->dev.kobj, NULL,
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index b3c35e33f1e7..62982f67d632 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -65,6 +65,7 @@
> /* Writing a brightness re-enables the screen if disabled */
> #define ASUS_WMI_DEVID_SCREENPAD_LIGHT 0x00050032
> #define ASUS_WMI_DEVID_FAN_BOOST_MODE 0x00110018
> +#define ASUS_WMI_DEVID_FAN_BOOST_MODE2 0x00110019
> #define ASUS_WMI_DEVID_THROTTLE_THERMAL_POLICY 0x00120075
>
> /* Misc */
> --
> 2.45.2
>
>
Thank you for the work on this. But I must point out that the same 0x00110019 method has already been submitted as a patch to work with the existing "throttle_thermal" functionality, which itself is also tied to platoform_profile class support.
See https://lore.kernel.org/platform-driver-x86/20240609144849.2532-1-mohamed.ghanmi@supcom.tn/T/#mcd18e74676084e21d5c15af84bc08d8c6b375fb9
If you could submit only the first patch instead please?
^ permalink raw reply
* Re: [PATCH RFC] LSM, net: Add SO_PEERCONTEXT for peer LSM data
From: Paul Moore @ 2024-06-20 21:05 UTC (permalink / raw)
To: Casey Schaufler, LSM List, netdev, linux-api,
Linux kernel mailing list
In-Reply-To: <763db426-6f60-4d36-b3f9-b316008889f7@schaufler-ca.com>
On May 13, 2024 Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> We recently introduced system calls to access process attributes that
> are used by Linux Security Modules (LSM). An important aspect of these
> system calls is that they provide the LSM attribute data in a format
> that identifies the LSM to which the data applies. Another aspect is that
> it can be used to provide multiple instances of the attribute for the
> case where more than one LSM supplies the attribute.
>
> We wish to take advantage of this format for data about network peers.
> The existing mechanism, SO_PEERSEC, provides peer security data as a
> text string. This is sufficient when the LSM providing the information
> is known by the user of SO_PEERSEC, and there is only one LSM providing
> the information. It fails, however, if the user does not know which
> LSM is providing the information.
>
> Discussions about extending SO_PEERSEC to accomodate either the new
Spelling nitpick -> "accommodate" :)
> format or some other encoding scheme invariably lead to the conclusion
> that doing so would lead to tears. Hence, we introduce SO_PEERCONTEXT
> which uses the same API data as the LSM system calls.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
> arch/alpha/include/uapi/asm/socket.h | 1 +
> arch/mips/include/uapi/asm/socket.h | 1 +
> arch/parisc/include/uapi/asm/socket.h | 1 +
> arch/sparc/include/uapi/asm/socket.h | 1 +
> include/linux/lsm_hook_defs.h | 2 +
> include/linux/security.h | 18 ++++++++
> include/uapi/asm-generic/socket.h | 1 +
> net/core/sock.c | 4 ++
> security/apparmor/lsm.c | 39 ++++++++++++++++
> security/security.c | 86 +++++++++++++++++++++++++++++++++++
> security/selinux/hooks.c | 35 ++++++++++++++
> security/smack/smack_lsm.c | 25 ++++++++++
> 12 files changed, 214 insertions(+)
...
> diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
> index 8ce8a39a1e5f..e0166ff53670 100644
> --- a/include/uapi/asm-generic/socket.h
> +++ b/include/uapi/asm-generic/socket.h
> @@ -134,6 +134,7 @@
>
> #define SO_PASSPIDFD 76
> #define SO_PEERPIDFD 77
> +#define SO_PEERCONTEXT 78
Bikeshed time ... how about SO_PEERLSMCTX since we are returning a
lsm_ctx struct?
> diff --git a/security/security.c b/security/security.c
> index e387614cb054..fd4919c28e8f 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -874,6 +874,64 @@ int lsm_fill_user_ctx(struct lsm_ctx __user *uctx, u32 *uctx_len,
> return rc;
> }
>
> +/**
> + * lsm_fill_socket_ctx - Fill a socket lsm_ctx structure
> + * @optval: a socket LSM context to be filled
> + * @optlen: uctx size
"@optlen: @optval size"
> + * @val: the new LSM context value
> + * @val_len: the size of the new LSM context value
> + * @id: LSM id
> + * @flags: LSM defined flags
> + *
> + * Fill all of the fields in a lsm_ctx structure. If @optval is NULL
> + * simply calculate the required size to output via @optlen and return
> + * success.
> + *
> + * Returns 0 on success, -E2BIG if userspace buffer is not large enough,
> + * -EFAULT on a copyout error, -ENOMEM if memory can't be allocated.
> + */
> +int lsm_fill_socket_ctx(sockptr_t optval, sockptr_t optlen, void *val,
> + size_t val_len, u64 id, u64 flags)
> +{
> + struct lsm_ctx *nctx = NULL;
> + unsigned int nctx_len;
> + int loptlen;
u32?
> + int rc = 0;
> +
> + if (copy_from_sockptr(&loptlen, optlen, sizeof(int)))
> + return -EFAULT;
It seems the current guidance prefers copy_safe_from_sockptr(), see
the note in include/linux/sockptr.h.
> + nctx_len = ALIGN(struct_size(nctx, ctx, val_len), sizeof(void *));
> + if (nctx_len > loptlen && !sockptr_is_null(optval))
> + rc = -E2BIG;
Why do we care if @optval is NULL or not? We are in a -E2BIG state,
we're not copying anything into @optval anyway. In fact, why are we
doing the @rc check below? Do it here like we do in lsm_fill_user_ctx().
if (nctx_len > loptlen) {
rc = -E2BIG;
goto out;
}
> + /* no buffer - return success/0 and set @uctx_len to the req size */
"... set @opt_len ... "
> + if (sockptr_is_null(optval) || rc)
> + goto out;
Do the @rc check above, not here.
> + nctx = kzalloc(nctx_len, GFP_KERNEL);
> + if (!nctx) {
> + rc = -ENOMEM;
> + goto out;
> + }
> + nctx->id = id;
> + nctx->flags = flags;
> + nctx->len = nctx_len;
> + nctx->ctx_len = val_len;
> + memcpy(nctx->ctx, val, val_len);
> +
> + if (copy_to_sockptr(optval, nctx, nctx_len))
> + rc = -EFAULT;
This is always going to copy to the start of @optval which means we
are going to keep overwriting previous values in the multi-LSM case.
I think we likely want copy_to_sockptr_offset(), or similar. See my
comment in security_socket_getpeerctx_stream().
> + kfree(nctx);
> +out:
> + if (copy_to_sockptr(optlen, &nctx_len, sizeof(int)))
> + rc = -EFAULT;
> +
> + return rc;
> +}
> +
> +
> /*
> * The default value of the LSM hook is defined in linux/lsm_hook_defs.h and
> * can be accessed with:
> @@ -4743,6 +4801,34 @@ int security_socket_getpeersec_stream(struct socket *sock, sockptr_t optval,
> return LSM_RET_DEFAULT(socket_getpeersec_stream);
> }
>
> +/**
> + * security_socket_getpeerctx_stream() - Get the remote peer label
> + * @sock: socket
> + * @optval: destination buffer
> + * @optlen: size of peer label copied into the buffer
> + * @len: maximum size of the destination buffer
> + *
> + * This hook allows the security module to provide peer socket security state
> + * for unix or connected tcp sockets to userspace via getsockopt
> + * SO_GETPEERCONTEXT. For tcp sockets this can be meaningful if the socket
> + * is associated with an ipsec SA.
> + *
> + * Return: Returns 0 if all is well, otherwise, typical getsockopt return
> + * values.
> + */
> +int security_socket_getpeerctx_stream(struct socket *sock, sockptr_t optval,
> + sockptr_t optlen, unsigned int len)
> +{
> + struct security_hook_list *hp;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeerctx_stream,
> + list)
> + return hp->hook.socket_getpeerctx_stream(sock, optval, optlen,
> + len);
> +
> + return LSM_RET_DEFAULT(socket_getpeerctx_stream);
> +}
Don't we need the same magic that we have in security_getselfattr() to
handle the multi-LSM case?
--
paul-moore.com
^ permalink raw reply
* Re: [PATCHv8 bpf-next 3/9] uprobe: Add uretprobe syscall to speed up return probe
From: Oleg Nesterov @ 2024-06-20 18:52 UTC (permalink / raw)
To: Guenter Roeck
Cc: Jiri Olsa, Steven Rostedt, Masami Hiramatsu, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, linux-kernel,
linux-trace-kernel, linux-api, linux-man, x86, bpf, Song Liu,
Yonghong Song, John Fastabend, Peter Zijlstra, Thomas Gleixner,
Borislav Petkov (AMD), Ingo Molnar, Andy Lutomirski,
Edgecombe, Rick P, Deepak Gupta
In-Reply-To: <054064c5-704a-4ea7-8a89-1e136e475437@roeck-us.net>
On 06/20, Guenter Roeck wrote:
>
> On Tue, Jun 11, 2024 at 01:21:52PM +0200, Jiri Olsa wrote:
> > Adding uretprobe syscall instead of trap to speed up return probe.
> >
>
> This patch results in:
>
> Building loongarch:allmodconfig ... failed
> --------------
> Error log:
> In file included from include/linux/uprobes.h:49,
> from include/linux/mm_types.h:16,
> from include/linux/mmzone.h:22,
> from include/linux/gfp.h:7,
> from include/linux/xarray.h:16,
> from include/linux/list_lru.h:14,
> from include/linux/fs.h:13,
> from include/linux/highmem.h:5,
> from kernel/events/uprobes.c:13:
> kernel/events/uprobes.c: In function 'arch_uprobe_trampoline':
> arch/loongarch/include/asm/uprobes.h:12:33: error: initializer element is not constant
should be fixed by https://lore.kernel.org/all/ZmyZgzqsowkGyqmH@krava/
in this thread.
but may be arch/loongarch should override __weak arch_uprobe_trampoline() ?
Oleg.
^ permalink raw reply
* Re: [PATCHv8 bpf-next 3/9] uprobe: Add uretprobe syscall to speed up return probe
From: Guenter Roeck @ 2024-06-20 18:19 UTC (permalink / raw)
To: Jiri Olsa
Cc: Steven Rostedt, Masami Hiramatsu, Oleg Nesterov,
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
linux-kernel, linux-trace-kernel, linux-api, linux-man, x86, bpf,
Song Liu, Yonghong Song, John Fastabend, Peter Zijlstra,
Thomas Gleixner, Borislav Petkov (AMD), Ingo Molnar,
Andy Lutomirski, Edgecombe, Rick P, Deepak Gupta
In-Reply-To: <20240611112158.40795-4-jolsa@kernel.org>
On Tue, Jun 11, 2024 at 01:21:52PM +0200, Jiri Olsa wrote:
> Adding uretprobe syscall instead of trap to speed up return probe.
>
This patch results in:
Building loongarch:allmodconfig ... failed
--------------
Error log:
In file included from include/linux/uprobes.h:49,
from include/linux/mm_types.h:16,
from include/linux/mmzone.h:22,
from include/linux/gfp.h:7,
from include/linux/xarray.h:16,
from include/linux/list_lru.h:14,
from include/linux/fs.h:13,
from include/linux/highmem.h:5,
from kernel/events/uprobes.c:13:
kernel/events/uprobes.c: In function 'arch_uprobe_trampoline':
arch/loongarch/include/asm/uprobes.h:12:33: error: initializer element is not constant
12 | #define UPROBE_SWBP_INSN larch_insn_gen_break(BRK_UPROBE_BP)
| ^~~~~~~~~~~~~~~~~~~~
kernel/events/uprobes.c:1479:39: note: in expansion of macro 'UPROBE_SWBP_INSN'
1479 | static uprobe_opcode_t insn = UPROBE_SWBP_INSN;
| ^~~~~~~~~~~~~~~~
Bisect log attached.
Guenter
---
# bad: [2102cb0d050d34d50b9642a3a50861787527e922] Add linux-next specific files for 20240619
# good: [6ba59ff4227927d3a8530fc2973b80e94b54d58f] Linux 6.10-rc4
git bisect start 'HEAD' 'v6.10-rc4'
# good: [a8fa5261ec87d5aafd3211548d93008d5739457d] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
git bisect good a8fa5261ec87d5aafd3211548d93008d5739457d
# good: [ee551f4db89753511a399b808db75654facec7c8] Merge branch 'for-linux-next' of https://gitlab.freedesktop.org/drm/i915/kernel
git bisect good ee551f4db89753511a399b808db75654facec7c8
# bad: [ec3557f4b791d72d93bfb69702d441d2c9f8cd0d] Merge branch 'next' of git://git.kernel.org/pub/scm/virt/kvm/kvm.git
git bisect bad ec3557f4b791d72d93bfb69702d441d2c9f8cd0d
# good: [29e7873afb5768f7af65802d021ee0c9bf2167be] Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm.git
git bisect good 29e7873afb5768f7af65802d021ee0c9bf2167be
# good: [ffe376e4a4ec29bb29d97664b72ff607e86f5b02] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
git bisect good ffe376e4a4ec29bb29d97664b72ff607e86f5b02
# bad: [39264a48da368f5394289133802f7d105dd3a33c] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
git bisect bad 39264a48da368f5394289133802f7d105dd3a33c
# good: [8af40c77dfe215cb8ad60c221d8eb740b056460b] Merge ftrace/for-next
git bisect good 8af40c77dfe215cb8ad60c221d8eb740b056460b
# bad: [5dfebf3c26dc5fe0fe08a5b4f334922b650e43b9] Merge ring-buffer/for-next
git bisect bad 5dfebf3c26dc5fe0fe08a5b4f334922b650e43b9
# bad: [9172a2da3b4162b5af0d2b57a30e844c451e74b7] Merge probes/for-next
git bisect bad 9172a2da3b4162b5af0d2b57a30e844c451e74b7
# bad: [29edd8b003db897d81d82d950785327f164650d3] selftests/x86: Add return uprobe shadow stack test
git bisect bad 29edd8b003db897d81d82d950785327f164650d3
# good: [1b3c86eeea7594eeeb49b8d1c1db0a40f0ce7920] samples: kprobes: add missing MODULE_DESCRIPTION() macros
git bisect good 1b3c86eeea7594eeeb49b8d1c1db0a40f0ce7920
# good: [190fec72df4a5d4d98b1e783c333f471e5e5f344] uprobe: Wire up uretprobe system call
git bisect good 190fec72df4a5d4d98b1e783c333f471e5e5f344
# bad: [ff474a78cef5cb5f32be52fe25b78441327a2e7c] uprobe: Add uretprobe syscall to speed up return probe
git bisect bad ff474a78cef5cb5f32be52fe25b78441327a2e7c
# first bad commit: [ff474a78cef5cb5f32be52fe25b78441327a2e7c] uprobe: Add uretprobe syscall to speed up return probe
^ permalink raw reply
* Re: [PATCH v18 2/5] random: add vgetrandom_alloc() syscall
From: Jason A. Donenfeld @ 2024-06-20 12:18 UTC (permalink / raw)
To: Aleksa Sarai
Cc: linux-kernel, patches, tglx, linux-crypto, linux-api, x86,
Greg Kroah-Hartman, Adhemerval Zanella Netto, Carlos O'Donell,
Florian Weimer, Arnd Bergmann, Jann Horn, Christian Brauner,
David Hildenbrand
In-Reply-To: <20240620.020423-puny.wheat.mobile.arm-1wWnJHwWYyAl@cyphar.com>
Hey Aleksa,
On Wed, Jun 19, 2024 at 07:13:26PM -0700, Aleksa Sarai wrote:
> Then again, I guess since libc is planned to be the primary user,
> creating a new syscall in a decade if necessary is probably not that big
> of an issue.
I'm not sure going the whole big struct thing is really necessary, and
for an additional reason: this is only meant to be used with the vDSO
function, which is also coupled with the kernel. It doesn't return
information that's made to be used (or allowed to be used) anywhere
else. So both the vdso code and the syscall code are part of the same
basic thing that will evolve together. So I'm not convinced extensible
struct really makes sense for this, as neat as it is.
If there's wide consensus that it's desirable, in contrast to what I'm
saying, I'm not vehemently opposed to it and could do it, but it just
seems like massive overkill and not at all necessary. Things are
intentionally as simple and straightforward as can be.
Jason
^ permalink raw reply
* [PATCH 1/2] platform/x86: asus-wmi: support camera disable LED
From: Devin Bayer @ 2024-06-20 8:22 UTC (permalink / raw)
To: corentin.chary, luke
Cc: hdegoede, platform-driver-x86, linux-kernel, linux-api,
ilpo.jarvinen, Devin Bayer
In-Reply-To: <20240620082223.20178-1-dev@doubly.so>
Support the LED on F10 above the crossed out camera icon.
Signed-off-by: Devin Bayer <dev@doubly.so>
---
drivers/platform/x86/asus-wmi.c | 36 ++++++++++++++++++++++
include/linux/platform_data/x86/asus-wmi.h | 2 ++
2 files changed, 38 insertions(+)
diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 3f9b6285c9a6..5585f15e7920 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -73,6 +73,7 @@ module_param(fnlock_default, bool, 0444);
#define NOTIFY_LID_FLIP_ROG 0xbd
#define ASUS_WMI_FNLOCK_BIOS_DISABLED BIT(0)
+#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
#define ASUS_MID_FAN_DESC "mid_fan"
#define ASUS_GPU_FAN_DESC "gpu_fan"
@@ -238,6 +239,7 @@ struct asus_wmi {
struct led_classdev lightbar_led;
int lightbar_led_wk;
struct led_classdev micmute_led;
+ struct led_classdev camera_led;
struct workqueue_struct *led_workqueue;
struct work_struct tpd_led_work;
struct work_struct wlan_led_work;
@@ -1642,6 +1644,27 @@ static int micmute_led_set(struct led_classdev *led_cdev,
return err < 0 ? err : 0;
}
+static enum led_brightness camera_led_get(struct led_classdev *led_cdev)
+{
+ struct asus_wmi *asus;
+ u32 result;
+
+ asus = container_of(led_cdev, struct asus_wmi, camera_led);
+ asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_CAMERA_LED, &result);
+
+ return result & ASUS_WMI_DSTS_BRIGHTNESS_MASK;
+}
+
+static int camera_led_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ int state = brightness != LED_OFF;
+ int err;
+
+ err = asus_wmi_set_devstate(ASUS_WMI_DEVID_CAMERA_LED, state, NULL);
+ return err < 0 ? err : 0;
+}
+
static void asus_wmi_led_exit(struct asus_wmi *asus)
{
led_classdev_unregister(&asus->kbd_led);
@@ -1649,6 +1672,7 @@ static void asus_wmi_led_exit(struct asus_wmi *asus)
led_classdev_unregister(&asus->wlan_led);
led_classdev_unregister(&asus->lightbar_led);
led_classdev_unregister(&asus->micmute_led);
+ led_classdev_unregister(&asus->camera_led);
if (asus->led_workqueue)
destroy_workqueue(asus->led_workqueue);
@@ -1740,6 +1764,18 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
goto error;
}
+ if (asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CAMERA_LED)) {
+ asus->camera_led.name = "platform::camera";
+ asus->camera_led.max_brightness = 1;
+ asus->camera_led.brightness_get = camera_led_get;
+ asus->camera_led.brightness_set_blocking = camera_led_set;
+
+ rv = led_classdev_register(&asus->platform_device->dev,
+ &asus->camera_led);
+ if (rv)
+ goto error;
+ }
+
error:
if (rv)
asus_wmi_led_exit(asus);
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 3eb5cd6773ad..b3c35e33f1e7 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -50,6 +50,8 @@
#define ASUS_WMI_DEVID_LED5 0x00020015
#define ASUS_WMI_DEVID_LED6 0x00020016
#define ASUS_WMI_DEVID_MICMUTE_LED 0x00040017
+#define ASUS_WMI_DEVID_CAMERA_LED_NEG 0x00060078
+#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
/* Backlight and Brightness */
#define ASUS_WMI_DEVID_ALS_ENABLE 0x00050001 /* Ambient Light Sensor */
--
2.45.2
^ permalink raw reply related
* [PATCH 2/2] platform/x86: asus-wmi: support newer fan_boost_mode dev_id
From: Devin Bayer @ 2024-06-20 8:22 UTC (permalink / raw)
To: corentin.chary, luke
Cc: hdegoede, platform-driver-x86, linux-kernel, linux-api,
ilpo.jarvinen, Devin Bayer
In-Reply-To: <20240620082223.20178-1-dev@doubly.so>
Support changing the fan mode (silent, performance, standard). I reused
the existing fan_boost_mode sysfs entry.
Signed-off-by: Devin Bayer <dev@doubly.so>
---
drivers/platform/x86/asus-wmi.c | 87 ++++++++++++++++++++--
include/linux/platform_data/x86/asus-wmi.h | 1 +
2 files changed, 82 insertions(+), 6 deletions(-)
diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 5585f15e7920..e27b8f86d57b 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -73,7 +73,6 @@ module_param(fnlock_default, bool, 0444);
#define NOTIFY_LID_FLIP_ROG 0xbd
#define ASUS_WMI_FNLOCK_BIOS_DISABLED BIT(0)
-#define ASUS_WMI_DEVID_CAMERA_LED 0x00060079
#define ASUS_MID_FAN_DESC "mid_fan"
#define ASUS_GPU_FAN_DESC "gpu_fan"
@@ -94,6 +93,10 @@ module_param(fnlock_default, bool, 0444);
#define ASUS_FAN_BOOST_MODE_SILENT_MASK 0x02
#define ASUS_FAN_BOOST_MODES_MASK 0x03
+#define ASUS_FAN_BOOST_MODE2_NORMAL 0
+#define ASUS_FAN_BOOST_MODE2_SILENT 1
+#define ASUS_FAN_BOOST_MODE2_OVERBOOST 2
+
#define ASUS_THROTTLE_THERMAL_POLICY_DEFAULT 0
#define ASUS_THROTTLE_THERMAL_POLICY_OVERBOOST 1
#define ASUS_THROTTLE_THERMAL_POLICY_SILENT 2
@@ -268,6 +271,7 @@ struct asus_wmi {
int agfn_pwm;
bool fan_boost_mode_available;
+ u32 fan_boost_mode_dev_id;
u8 fan_boost_mode_mask;
u8 fan_boost_mode;
@@ -3019,14 +3023,14 @@ static int asus_wmi_fan_init(struct asus_wmi *asus)
/* Fan mode *******************************************************************/
-static int fan_boost_mode_check_present(struct asus_wmi *asus)
+static int fan_boost_mode1_check_present(struct asus_wmi *asus)
{
u32 result;
int err;
- asus->fan_boost_mode_available = false;
+ asus->fan_boost_mode_dev_id = ASUS_WMI_DEVID_FAN_BOOST_MODE;
- err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_FAN_BOOST_MODE,
+ err = asus_wmi_get_devstate(asus, asus->fan_boost_mode_dev_id,
&result);
if (err) {
if (err == -ENODEV)
@@ -3044,16 +3048,87 @@ static int fan_boost_mode_check_present(struct asus_wmi *asus)
return 0;
}
+static int fan_boost_mode2_check_present(struct asus_wmi *asus)
+{
+ u32 result;
+ int err;
+
+ asus->fan_boost_mode_mask = ASUS_FAN_BOOST_MODES_MASK;
+ asus->fan_boost_mode_dev_id = ASUS_WMI_DEVID_FAN_BOOST_MODE2;
+
+ err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_FAN_BOOST_MODE2,
+ &result);
+ if (err) {
+ if (err == -ENODEV)
+ return 0;
+ else
+ return err;
+ }
+
+ if (! (result & ASUS_WMI_DSTS_PRESENCE_BIT))
+ return 0;
+
+ asus->fan_boost_mode_available = true;
+
+ if (result & ASUS_FAN_BOOST_MODE2_SILENT) {
+ asus->fan_boost_mode = ASUS_FAN_BOOST_MODE_SILENT;
+ } else if(result & ASUS_FAN_BOOST_MODE2_OVERBOOST) {
+ asus->fan_boost_mode = ASUS_FAN_BOOST_MODE_OVERBOOST;
+ } else {
+ asus->fan_boost_mode = ASUS_FAN_BOOST_MODE_NORMAL;
+ }
+
+ return 0;
+}
+
+static int fan_boost_mode_check_present(struct asus_wmi *asus)
+{
+ int err;
+
+ asus->fan_boost_mode_available = false;
+
+ err = fan_boost_mode1_check_present(asus);
+ if (err)
+ return err;
+
+ if (!asus->fan_boost_mode_available) {
+ err = fan_boost_mode2_check_present(asus);
+ }
+
+ return err;
+}
+
static int fan_boost_mode_write(struct asus_wmi *asus)
{
u32 retval;
u8 value;
+ u8 hw_value;
int err;
value = asus->fan_boost_mode;
- pr_info("Set fan boost mode: %u\n", value);
- err = asus_wmi_set_devstate(ASUS_WMI_DEVID_FAN_BOOST_MODE, value,
+ /* transform userspace values into hardware values */
+ if(asus->fan_boost_mode_dev_id == ASUS_WMI_DEVID_FAN_BOOST_MODE2) {
+ switch(value) {
+ case ASUS_FAN_BOOST_MODE_SILENT:
+ hw_value = ASUS_FAN_BOOST_MODE2_SILENT;
+ break;
+ case ASUS_FAN_BOOST_MODE_OVERBOOST:
+ hw_value = ASUS_FAN_BOOST_MODE2_OVERBOOST;
+ break;
+ case ASUS_FAN_BOOST_MODE_NORMAL:
+ hw_value = ASUS_FAN_BOOST_MODE2_NORMAL;
+ break;
+ default:
+ return -EINVAL;
+
+ }
+ } else {
+ hw_value = value;
+ }
+
+ pr_info("Set fan boost mode: user=%u hw=%u\n", value, hw_value);
+ err = asus_wmi_set_devstate(asus->fan_boost_mode_dev_id, hw_value,
&retval);
sysfs_notify(&asus->platform_device->dev.kobj, NULL,
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index b3c35e33f1e7..62982f67d632 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -65,6 +65,7 @@
/* Writing a brightness re-enables the screen if disabled */
#define ASUS_WMI_DEVID_SCREENPAD_LIGHT 0x00050032
#define ASUS_WMI_DEVID_FAN_BOOST_MODE 0x00110018
+#define ASUS_WMI_DEVID_FAN_BOOST_MODE2 0x00110019
#define ASUS_WMI_DEVID_THROTTLE_THERMAL_POLICY 0x00120075
/* Misc */
--
2.45.2
^ permalink raw reply related
* [PATCH 0/2] platform/x86: asus-wmi: support a couple Zenbook 2023 features
From: Devin Bayer @ 2024-06-20 8:22 UTC (permalink / raw)
To: corentin.chary, luke
Cc: hdegoede, platform-driver-x86, linux-kernel, linux-api,
ilpo.jarvinen, Devin Bayer
This patch series adds support for a couple features on
my Zenbook UX3404VC:
1. the LED on F11 "disable camera" key
2. fan speed control
Devin Bayer (2):
platform/x86: asus-wmi: support camera disable LED
platform/x86: asus-wmi: support newer fan_boost_mode dev_id
drivers/platform/x86/asus-wmi.c | 121 ++++++++++++++++++++-
include/linux/platform_data/x86/asus-wmi.h | 3 +
2 files changed, 119 insertions(+), 5 deletions(-)
--
2.45.2
^ permalink raw reply
* Re: [PATCH v18 2/5] random: add vgetrandom_alloc() syscall
From: Aleksa Sarai @ 2024-06-20 2:13 UTC (permalink / raw)
To: Jason A. Donenfeld
Cc: linux-kernel, patches, tglx, linux-crypto, linux-api, x86,
Greg Kroah-Hartman, Adhemerval Zanella Netto, Carlos O'Donell,
Florian Weimer, Arnd Bergmann, Jann Horn, Christian Brauner,
David Hildenbrand
In-Reply-To: <20240620005339.1273434-3-Jason@zx2c4.com>
[-- Attachment #1: Type: text/plain, Size: 15752 bytes --]
On 2024-06-20, Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> The vDSO getrandom() works over an opaque per-thread state of an
> unexported size, which must be marked VM_WIPEONFORK, VM_DONTDUMP,
> VM_NORESERVE, and VM_DROPPABLE for proper operation. Over time, the
> nuances of these allocations may change or grow or even differ based on
> architectural features.
>
> The syscall has the signature:
>
> void *vgetrandom_alloc(unsigned int *num, unsigned int *size_per_each,
> unsigned long addr, unsigned int flags);
>
> This takes a hinted number of opaque states in `num`, and returns a
> pointer to an array of opaque states, the number actually allocated back
> in `num`, and the size in bytes of each one in `size_per_each`, enabling
> a libc to slice up the returned array into a state per each thread,
> while ensuring that no single state straddles a page boundary. (The
> `flags` and `addr` arguments, as well as the `*size_per_each` input
> value, are reserved for the future and are forced to be zero zero for
> now.)
Given how many flags are going to be reserved at the outset, what about
using an extensible struct (copy_struct_from_user) instead? If you're
absolutely sure you'll never need more arguments that's fine, but it
seems entirely possible to me that you might need an extra argument in a
few years.
Since you need to write to *num in the current syscall, I suspect the
following would be nicer as well.
struct vgetrandom_args {
u64 num;
}
void *vgetrandom_alloc(struct vgetrandom_args *arg, size_t size);
If you'd prefer to have flags from the outset (even though you could
extend them later without issues), then
struct vgetrandom_args {
u64 flags;
u64 num;
}
would also work.
Then again, I guess since libc is planned to be the primary user,
creating a new syscall in a decade if necessary is probably not that big
of an issue.
> Libc is expected to allocate a chunk of these on first use, and then
> dole them out to threads as they're created, allocating more when
> needed. The returned address of the first state may be passed to
> munmap(2) with a length of `DIV_ROUND_UP(num, PAGE_SIZE / size_per_each)
> * PAGE_SIZE`, in order to deallocate the memory.
>
> We very intentionally do *not* leave state allocation for vDSO
> getrandom() up to userspace itself, but rather provide this new syscall
> for such allocations. vDSO getrandom() must not store its state in just
> any old memory address, but rather just ones that the kernel specially
> allocates for it, leaving the particularities of those allocations up to
> the kernel.
>
> The allocation of states is intended to be integrated into libc's thread
> management. As an illustrative example, the following code might be used
> to do the same outside of libc. Though, vgetrandom_alloc() is not
> expected to be exposed outside of libc, and the pthread usage here is
> expected to be elided into libc internals. This allocation scheme is
> very naive and does not shrink; other implementations may choose to be
> more complex.
>
> static void *vgetrandom_alloc(unsigned int *num, unsigned int *size_per_each)
> {
> *size_per_each = 0; /* Must be zero on input. */
> return (void *)syscall(__NR_vgetrandom_alloc, &num, &size_per_each,
> 0 /* reserved @addr */, 0 /* reserved @flags */);
> }
>
> static struct {
> pthread_mutex_t lock;
> void **states;
> size_t len, cap, size_per_each;
> } grnd_allocator = {
> .lock = PTHREAD_MUTEX_INITIALIZER
> };
>
> static void *vgetrandom_get_state(void)
> {
> void *state = NULL;
>
> pthread_mutex_lock(&grnd_allocator.lock);
> if (!grnd_allocator.len) {
> size_t new_cap;
> size_t page_size = getpagesize();
> unsigned int num = sysconf(_SC_NPROCESSORS_ONLN); /* Could be arbitrary, just a hint. */
> unsigned int size_per_each;
> void *new_block = vgetrandom_alloc(&num, &size_per_each);
> void *new_states;
>
> if (new_block == MAP_FAILED)
> goto out;
> if (grnd_allocator.size_per_each && grnd_allocator.size_per_each != size_per_each)
> goto unmap;
> grnd_allocator.size_per_each = size_per_each;
> new_cap = grnd_allocator.cap + num;
> new_states = reallocarray(grnd_allocator.states, new_cap, sizeof(*grnd_allocator.states));
> if (!new_states)
> goto unmap;
> grnd_allocator.cap = new_cap;
> grnd_allocator.states = new_states;
>
> for (size_t i = 0; i < num; ++i) {
> grnd_allocator.states[i] = new_block;
> if (((uintptr_t)new_block & (page_size - 1)) + size_per_each > page_size)
> new_block = (void *)(((uintptr_t)new_block + page_size) & (page_size - 1));
> else
> new_block += size_per_each;
> }
> grnd_allocator.len = num;
> goto success;
>
> unmap:
> munmap(new_block, DIV_ROUND_UP(num, page_size / size_per_each) * page_size);
> goto out;
> }
> success:
> state = grnd_allocator.states[--grnd_allocator.len];
>
> out:
> pthread_mutex_unlock(&grnd_allocator.lock);
> return state;
> }
>
> static void vgetrandom_put_state(void *state)
> {
> if (!state)
> return;
> pthread_mutex_lock(&grnd_allocator.lock);
> grnd_allocator.states[grnd_allocator.len++] = state;
> pthread_mutex_unlock(&grnd_allocator.lock);
> }
>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
> MAINTAINERS | 1 +
> drivers/char/random.c | 135 ++++++++++++++++++++++++++++++++++++++-
> include/linux/syscalls.h | 3 +
> include/vdso/getrandom.h | 16 +++++
> kernel/sys_ni.c | 3 +
> lib/vdso/Kconfig | 6 ++
> 6 files changed, 163 insertions(+), 1 deletion(-)
> create mode 100644 include/vdso/getrandom.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 8aa17e515ef3..8480c4c39915 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -18747,6 +18747,7 @@ T: git https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git
> F: Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml
> F: drivers/char/random.c
> F: drivers/virt/vmgenid.c
> +F: include/vdso/getrandom.h
>
> RAPIDIO SUBSYSTEM
> M: Matt Porter <mporter@kernel.crashing.org>
> diff --git a/drivers/char/random.c b/drivers/char/random.c
> index 2597cb43f438..ccb35f390c85 100644
> --- a/drivers/char/random.c
> +++ b/drivers/char/random.c
> @@ -1,6 +1,6 @@
> // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> /*
> - * Copyright (C) 2017-2022 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
> + * Copyright (C) 2017-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
> * Copyright Matt Mackall <mpm@selenic.com>, 2003, 2004, 2005
> * Copyright Theodore Ts'o, 1994, 1995, 1996, 1997, 1998, 1999. All rights reserved.
> *
> @@ -8,6 +8,7 @@
> * into roughly six sections, each with a section header:
> *
> * - Initialization and readiness waiting.
> + * - vDSO support helpers.
> * - Fast key erasure RNG, the "crng".
> * - Entropy accumulation and extraction routines.
> * - Entropy collection routines.
> @@ -39,6 +40,7 @@
> #include <linux/blkdev.h>
> #include <linux/interrupt.h>
> #include <linux/mm.h>
> +#include <linux/mman.h>
> #include <linux/nodemask.h>
> #include <linux/spinlock.h>
> #include <linux/kthread.h>
> @@ -56,6 +58,9 @@
> #include <linux/sched/isolation.h>
> #include <crypto/chacha.h>
> #include <crypto/blake2s.h>
> +#ifdef CONFIG_VDSO_GETRANDOM
> +#include <vdso/getrandom.h>
> +#endif
> #include <asm/archrandom.h>
> #include <asm/processor.h>
> #include <asm/irq.h>
> @@ -169,6 +174,134 @@ int __cold execute_with_initialized_rng(struct notifier_block *nb)
> __func__, (void *)_RET_IP_, crng_init)
>
>
> +
> +/********************************************************************
> + *
> + * vDSO support helpers.
> + *
> + * The actual vDSO function is defined over in lib/vdso/getrandom.c,
> + * but this section contains the kernel-mode helpers to support that.
> + *
> + ********************************************************************/
> +
> +#ifdef CONFIG_VDSO_GETRANDOM
> +/**
> + * sys_vgetrandom_alloc - Allocate opaque states for use with vDSO getrandom().
> + *
> + * @num: On input, a pointer to a suggested hint of how many states to
> + * allocate, and on return the number of states actually allocated.
> + *
> + * @size_per_each: On input, must be zero. On return, the size of each state allocated,
> + * so that the caller can split up the returned allocation into
> + * individual states.
> + *
> + * @addr: Reserved, must be zero.
> + *
> + * @flags: Reserved, must be zero.
> + *
> + * The getrandom() vDSO function in userspace requires an opaque state, which
> + * this function allocates by mapping a certain number of special pages into
> + * the calling process. It takes a hint as to the number of opaque states
> + * desired, and provides the caller with the number of opaque states actually
> + * allocated, the size of each one in bytes, and the address of the first
> + * state, which may be split up into @num states of @size_per_each bytes each,
> + * by adding @size_per_each to the returned first state @num times, while
> + * ensuring that no single state straddles a page boundary.
> + *
> + * Returns the address of the first state in the allocation on success, or a
> + * negative error value on failure.
> + *
> + * The returned address of the first state may be passed to munmap(2) with a
> + * length of `DIV_ROUND_UP(num, PAGE_SIZE / size_per_each) * PAGE_SIZE`, in
> + * order to deallocate the memory, after which it is invalid to pass it to vDSO
> + * getrandom().
> + *
> + * States allocated by this function must not be dereferenced, written, read,
> + * or otherwise manipulated. The *only* supported operations are:
> + * - Splitting up the states in intervals of @size_per_each, no more than
> + * @num times from the first state, while ensuring that no single state
> + * straddles a page boundary.
> + * - Passing a state to the getrandom() vDSO function's @opaque_state
> + * parameter, but not passing the same state at the same time to two such
> + * calls.
> + * - Passing the first state and the total length to munmap(2), as described
> + * above.
> + * All other uses are undefined behavior, which is subject to change or removal.
> + */
> +SYSCALL_DEFINE4(vgetrandom_alloc, unsigned int __user *, num,
> + unsigned int __user *, size_per_each, unsigned long, addr,
> + unsigned int, flags)
> +{
> + size_t state_size, alloc_size, num_states;
> + unsigned long pages_addr, populate;
> + unsigned int num_hint;
> + vm_flags_t vm_flags;
> + int ret;
> +
> + /*
> + * @flags and @addr are currently unused, so in order to reserve them
> + * for the future, force them to be set to zero by current callers.
> + */
> + if (flags || addr)
> + return -EINVAL;
> +
> + /*
> + * Also enforce that *size_per_each is zero on input, in case this becomes
> + * useful later on.
> + */
> + if (get_user(num_hint, size_per_each))
> + return -EFAULT;
> + if (num_hint)
> + return -EINVAL;
> +
> + if (get_user(num_hint, num))
> + return -EFAULT;
> +
> + state_size = sizeof(struct vgetrandom_state);
> + num_states = clamp_t(size_t, num_hint, 1, (SIZE_MAX & PAGE_MASK) / state_size);
> + alloc_size = PAGE_ALIGN(num_states * state_size);
> + /*
> + * States cannot straddle page boundaries, so calculate the number of
> + * states that can fit inside of a page without being split, and then
> + * multiply that out by the number of pages allocated.
> + */
> + num_states = (PAGE_SIZE / state_size) * (alloc_size / PAGE_SIZE);
> +
> + vm_flags =
> + /*
> + * Don't allow state to be written to swap, to preserve forward secrecy.
> + * But also don't mlock it or pre-reserve it, and allow it to
> + * be discarded under memory pressure. If no memory is available, returns
> + * zeros rather than segfaulting.
> + */
> + VM_DROPPABLE | VM_NORESERVE |
> +
> + /* Don't allow the state to survive forks, to prevent random number re-use. */
> + VM_WIPEONFORK |
> +
> + /* Don't write random state into coredumps. */
> + VM_DONTDUMP;
> +
> + if (mmap_write_lock_killable(current->mm))
> + return -EINTR;
> + pages_addr = do_mmap(NULL, 0, alloc_size, PROT_READ | PROT_WRITE,
> + MAP_PRIVATE | MAP_ANONYMOUS, vm_flags, 0, &populate, NULL);
> + mmap_write_unlock(current->mm);
> + if (IS_ERR_VALUE(pages_addr))
> + return pages_addr;
> +
> + ret = -EFAULT;
> + if (put_user(num_states, num) || put_user(state_size, size_per_each))
> + goto err_unmap;
> +
> + return pages_addr;
> +
> +err_unmap:
> + vm_munmap(pages_addr, alloc_size);
> + return ret;
> +}
> +#endif
> +
> /*********************************************************************
> *
> * Fast key erasure RNG, the "crng".
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 9104952d323d..56368ea4f510 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -906,6 +906,9 @@ asmlinkage long sys_seccomp(unsigned int op, unsigned int flags,
> void __user *uargs);
> asmlinkage long sys_getrandom(char __user *buf, size_t count,
> unsigned int flags);
> +asmlinkage long sys_vgetrandom_alloc(unsigned int __user *num,
> + unsigned int __user *size_per_each,
> + unsigned long addr, unsigned int flags);
> asmlinkage long sys_memfd_create(const char __user *uname_ptr, unsigned int flags);
> asmlinkage long sys_bpf(int cmd, union bpf_attr *attr, unsigned int size);
> asmlinkage long sys_execveat(int dfd, const char __user *filename,
> diff --git a/include/vdso/getrandom.h b/include/vdso/getrandom.h
> new file mode 100644
> index 000000000000..69037519d20b
> --- /dev/null
> +++ b/include/vdso/getrandom.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
> + */
> +
> +#ifndef _VDSO_GETRANDOM_H
> +#define _VDSO_GETRANDOM_H
> +
> +/**
> + * struct vgetrandom_state - State used by vDSO getrandom() and allocated by vgetrandom_alloc().
> + *
> + * Currently empty, as the vDSO getrandom() function has not yet been implemented.
> + */
> +struct vgetrandom_state { int placeholder; };
> +
> +#endif /* _VDSO_GETRANDOM_H */
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index d7eee421d4bc..6b17fadb0f59 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -272,6 +272,9 @@ COND_SYSCALL(pkey_free);
> /* memfd_secret */
> COND_SYSCALL(memfd_secret);
>
> +/* random */
> +COND_SYSCALL(vgetrandom_alloc);
> +
> /*
> * Architecture specific weak syscall entries.
> */
> diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig
> index c46c2300517c..99661b731834 100644
> --- a/lib/vdso/Kconfig
> +++ b/lib/vdso/Kconfig
> @@ -38,3 +38,9 @@ config GENERIC_VDSO_OVERFLOW_PROTECT
> in the hotpath.
>
> endif
> +
> +config VDSO_GETRANDOM
> + bool
> + select NEED_VM_DROPPABLE
> + help
> + Selected by architectures that support vDSO getrandom().
> --
> 2.45.2
>
>
--
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]
^ permalink raw reply
* [PATCH v18 5/5] x86: vdso: Wire up getrandom() vDSO implementation
From: Jason A. Donenfeld @ 2024-06-20 0:53 UTC (permalink / raw)
To: linux-kernel, patches, tglx
Cc: Jason A. Donenfeld, linux-crypto, linux-api, x86,
Greg Kroah-Hartman, Adhemerval Zanella Netto, Carlos O'Donell,
Florian Weimer, Arnd Bergmann, Jann Horn, Christian Brauner,
David Hildenbrand, Samuel Neves
In-Reply-To: <20240620005339.1273434-1-Jason@zx2c4.com>
Hook up the generic vDSO implementation to the x86 vDSO data page. Since
the existing vDSO infrastructure is heavily based on the timekeeping
functionality, which works over arrays of bases, a new macro is
introduced for vvars that are not arrays.
The vDSO function requires a ChaCha20 implementation that does not write
to the stack, yet can still do an entire ChaCha20 permutation, so
provide this using SSE2, since this is userland code that must work on
all x86-64 processors. There's a simple test for this code as well.
Reviewed-by: Samuel Neves <sneves@dei.uc.pt> # for vgetrandom-chacha.S
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
arch/x86/Kconfig | 1 +
arch/x86/entry/vdso/Makefile | 3 +-
arch/x86/entry/vdso/vdso.lds.S | 2 +
arch/x86/entry/vdso/vgetrandom-chacha.S | 178 ++++++++++++++++++
arch/x86/entry/vdso/vgetrandom.c | 17 ++
arch/x86/include/asm/vdso/getrandom.h | 55 ++++++
arch/x86/include/asm/vdso/vsyscall.h | 2 +
arch/x86/include/asm/vvar.h | 16 ++
tools/testing/selftests/vDSO/.gitignore | 1 +
tools/testing/selftests/vDSO/Makefile | 15 ++
.../testing/selftests/vDSO/vdso_test_chacha.c | 43 +++++
11 files changed, 332 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/entry/vdso/vgetrandom-chacha.S
create mode 100644 arch/x86/entry/vdso/vgetrandom.c
create mode 100644 arch/x86/include/asm/vdso/getrandom.h
create mode 100644 tools/testing/selftests/vDSO/vdso_test_chacha.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d7122a1883e..9c98b7a88cc2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -287,6 +287,7 @@ config X86
select HAVE_UNSTABLE_SCHED_CLOCK
select HAVE_USER_RETURN_NOTIFIER
select HAVE_GENERIC_VDSO
+ select VDSO_GETRANDOM if X86_64
select HOTPLUG_PARALLEL if SMP && X86_64
select HOTPLUG_SMT if SMP
select HOTPLUG_SPLIT_STARTUP if SMP && X86_32
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 215a1b202a91..c9216ac4fb1e 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -7,7 +7,7 @@
include $(srctree)/lib/vdso/Makefile
# Files to link into the vDSO:
-vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
+vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vgetrandom.o vgetrandom-chacha.o
vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
vobjs32-y += vdso32/vclock_gettime.o vdso32/vgetcpu.o
vobjs-$(CONFIG_X86_SGX) += vsgx.o
@@ -73,6 +73,7 @@ CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
CFLAGS_REMOVE_vgetcpu.o = -pg
CFLAGS_REMOVE_vdso32/vgetcpu.o = -pg
CFLAGS_REMOVE_vsgx.o = -pg
+CFLAGS_REMOVE_vgetrandom.o = -pg
#
# X32 processes use x32 vDSO to access 64bit kernel data.
diff --git a/arch/x86/entry/vdso/vdso.lds.S b/arch/x86/entry/vdso/vdso.lds.S
index e8c60ae7a7c8..0bab5f4af6d1 100644
--- a/arch/x86/entry/vdso/vdso.lds.S
+++ b/arch/x86/entry/vdso/vdso.lds.S
@@ -30,6 +30,8 @@ VERSION {
#ifdef CONFIG_X86_SGX
__vdso_sgx_enter_enclave;
#endif
+ getrandom;
+ __vdso_getrandom;
local: *;
};
}
diff --git a/arch/x86/entry/vdso/vgetrandom-chacha.S b/arch/x86/entry/vdso/vgetrandom-chacha.S
new file mode 100644
index 000000000000..bcba5639b8ee
--- /dev/null
+++ b/arch/x86/entry/vdso/vgetrandom-chacha.S
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include <linux/linkage.h>
+#include <asm/frame.h>
+
+.section .rodata, "a"
+.align 16
+CONSTANTS: .octa 0x6b20657479622d323320646e61707865
+.text
+
+/*
+ * Very basic SSE2 implementation of ChaCha20. Produces a given positive number
+ * of blocks of output with a nonce of 0, taking an input key and 8-byte
+ * counter. Importantly does not spill to the stack. Its arguments are:
+ *
+ * rdi: output bytes
+ * rsi: 32-byte key input
+ * rdx: 8-byte counter input/output
+ * rcx: number of 64-byte blocks to write to output
+ */
+SYM_FUNC_START(__arch_chacha20_blocks_nostack)
+
+.set output, %rdi
+.set key, %rsi
+.set counter, %rdx
+.set nblocks, %rcx
+.set i, %al
+/* xmm registers are *not* callee-save. */
+.set temp, %xmm0
+.set state0, %xmm1
+.set state1, %xmm2
+.set state2, %xmm3
+.set state3, %xmm4
+.set copy0, %xmm5
+.set copy1, %xmm6
+.set copy2, %xmm7
+.set copy3, %xmm8
+.set one, %xmm9
+
+ /* copy0 = "expand 32-byte k" */
+ movaps CONSTANTS(%rip),copy0
+ /* copy1,copy2 = key */
+ movups 0x00(key),copy1
+ movups 0x10(key),copy2
+ /* copy3 = counter || zero nonce */
+ movq 0x00(counter),copy3
+ /* one = 1 || 0 */
+ movq $1,%rax
+ movq %rax,one
+
+.Lblock:
+ /* state0,state1,state2,state3 = copy0,copy1,copy2,copy3 */
+ movdqa copy0,state0
+ movdqa copy1,state1
+ movdqa copy2,state2
+ movdqa copy3,state3
+
+ movb $10,i
+.Lpermute:
+ /* state0 += state1, state3 = rotl32(state3 ^ state0, 16) */
+ paddd state1,state0
+ pxor state0,state3
+ movdqa state3,temp
+ pslld $16,temp
+ psrld $16,state3
+ por temp,state3
+
+ /* state2 += state3, state1 = rotl32(state1 ^ state2, 12) */
+ paddd state3,state2
+ pxor state2,state1
+ movdqa state1,temp
+ pslld $12,temp
+ psrld $20,state1
+ por temp,state1
+
+ /* state0 += state1, state3 = rotl32(state3 ^ state0, 8) */
+ paddd state1,state0
+ pxor state0,state3
+ movdqa state3,temp
+ pslld $8,temp
+ psrld $24,state3
+ por temp,state3
+
+ /* state2 += state3, state1 = rotl32(state1 ^ state2, 7) */
+ paddd state3,state2
+ pxor state2,state1
+ movdqa state1,temp
+ pslld $7,temp
+ psrld $25,state1
+ por temp,state1
+
+ /* state1[0,1,2,3] = state1[1,2,3,0] */
+ pshufd $0x39,state1,state1
+ /* state2[0,1,2,3] = state2[2,3,0,1] */
+ pshufd $0x4e,state2,state2
+ /* state3[0,1,2,3] = state3[3,0,1,2] */
+ pshufd $0x93,state3,state3
+
+ /* state0 += state1, state3 = rotl32(state3 ^ state0, 16) */
+ paddd state1,state0
+ pxor state0,state3
+ movdqa state3,temp
+ pslld $16,temp
+ psrld $16,state3
+ por temp,state3
+
+ /* state2 += state3, state1 = rotl32(state1 ^ state2, 12) */
+ paddd state3,state2
+ pxor state2,state1
+ movdqa state1,temp
+ pslld $12,temp
+ psrld $20,state1
+ por temp,state1
+
+ /* state0 += state1, state3 = rotl32(state3 ^ state0, 8) */
+ paddd state1,state0
+ pxor state0,state3
+ movdqa state3,temp
+ pslld $8,temp
+ psrld $24,state3
+ por temp,state3
+
+ /* state2 += state3, state1 = rotl32(state1 ^ state2, 7) */
+ paddd state3,state2
+ pxor state2,state1
+ movdqa state1,temp
+ pslld $7,temp
+ psrld $25,state1
+ por temp,state1
+
+ /* state1[0,1,2,3] = state1[3,0,1,2] */
+ pshufd $0x93,state1,state1
+ /* state2[0,1,2,3] = state2[2,3,0,1] */
+ pshufd $0x4e,state2,state2
+ /* state3[0,1,2,3] = state3[1,2,3,0] */
+ pshufd $0x39,state3,state3
+
+ decb i
+ jnz .Lpermute
+
+ /* output0 = state0 + copy0 */
+ paddd copy0,state0
+ movups state0,0x00(output)
+ /* output1 = state1 + copy1 */
+ paddd copy1,state1
+ movups state1,0x10(output)
+ /* output2 = state2 + copy2 */
+ paddd copy2,state2
+ movups state2,0x20(output)
+ /* output3 = state3 + copy3 */
+ paddd copy3,state3
+ movups state3,0x30(output)
+
+ /* ++copy3.counter */
+ paddq one,copy3
+
+ /* output += 64, --nblocks */
+ addq $64,output
+ decq nblocks
+ jnz .Lblock
+
+ /* counter = copy3.counter */
+ movq copy3,0x00(counter)
+
+ /* Zero out the potentially sensitive regs, in case nothing uses these again. */
+ pxor state0,state0
+ pxor state1,state1
+ pxor state2,state2
+ pxor state3,state3
+ pxor copy1,copy1
+ pxor copy2,copy2
+ pxor temp,temp
+
+ ret
+SYM_FUNC_END(__arch_chacha20_blocks_nostack)
diff --git a/arch/x86/entry/vdso/vgetrandom.c b/arch/x86/entry/vdso/vgetrandom.c
new file mode 100644
index 000000000000..52d3c7faae2e
--- /dev/null
+++ b/arch/x86/entry/vdso/vgetrandom.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+#include <linux/types.h>
+
+#include "../../../../lib/vdso/getrandom.c"
+
+ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len);
+
+ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len)
+{
+ return __cvdso_getrandom(buffer, len, flags, opaque_state, opaque_len);
+}
+
+ssize_t getrandom(void *, size_t, unsigned int, void *, size_t)
+ __attribute__((weak, alias("__vdso_getrandom")));
diff --git a/arch/x86/include/asm/vdso/getrandom.h b/arch/x86/include/asm/vdso/getrandom.h
new file mode 100644
index 000000000000..b96e674cafde
--- /dev/null
+++ b/arch/x86/include/asm/vdso/getrandom.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+#ifndef __ASM_VDSO_GETRANDOM_H
+#define __ASM_VDSO_GETRANDOM_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/unistd.h>
+#include <asm/vvar.h>
+
+/**
+ * getrandom_syscall - Invoke the getrandom() syscall.
+ * @buffer: Destination buffer to fill with random bytes.
+ * @len: Size of @buffer in bytes.
+ * @flags: Zero or more GRND_* flags.
+ * Returns: The number of random bytes written to @buffer, or a negative value indicating an error.
+ */
+static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
+{
+ long ret;
+
+ asm ("syscall" : "=a" (ret) :
+ "0" (__NR_getrandom), "D" (buffer), "S" (len), "d" (flags) :
+ "rcx", "r11", "memory");
+
+ return ret;
+}
+
+#define __vdso_rng_data (VVAR(_vdso_rng_data))
+
+static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void)
+{
+ if (IS_ENABLED(CONFIG_TIME_NS) && __vdso_data->clock_mode == VDSO_CLOCKMODE_TIMENS)
+ return (void *)&__vdso_rng_data + ((void *)&__timens_vdso_data - (void *)&__vdso_data);
+ return &__vdso_rng_data;
+}
+
+/**
+ * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack.
+ * @dst_bytes: Destination buffer to hold @nblocks * 64 bytes of output.
+ * @key: 32-byte input key.
+ * @counter: 8-byte counter, read on input and updated on return.
+ * @nblocks: Number of blocks to generate.
+ *
+ * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write
+ * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data
+ * leaking into forked child processes.
+ */
+extern void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks);
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_GETRANDOM_H */
diff --git a/arch/x86/include/asm/vdso/vsyscall.h b/arch/x86/include/asm/vdso/vsyscall.h
index be199a9b2676..71c56586a22f 100644
--- a/arch/x86/include/asm/vdso/vsyscall.h
+++ b/arch/x86/include/asm/vdso/vsyscall.h
@@ -11,6 +11,8 @@
#include <asm/vvar.h>
DEFINE_VVAR(struct vdso_data, _vdso_data);
+DEFINE_VVAR_SINGLE(struct vdso_rng_data, _vdso_rng_data);
+
/*
* Update the vDSO data page to keep in sync with kernel timekeeping.
*/
diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
index 183e98e49ab9..9d9af37f7cab 100644
--- a/arch/x86/include/asm/vvar.h
+++ b/arch/x86/include/asm/vvar.h
@@ -26,6 +26,8 @@
*/
#define DECLARE_VVAR(offset, type, name) \
EMIT_VVAR(name, offset)
+#define DECLARE_VVAR_SINGLE(offset, type, name) \
+ EMIT_VVAR(name, offset)
#else
@@ -37,6 +39,10 @@ extern char __vvar_page;
extern type timens_ ## name[CS_BASES] \
__attribute__((visibility("hidden"))); \
+#define DECLARE_VVAR_SINGLE(offset, type, name) \
+ extern type vvar_ ## name \
+ __attribute__((visibility("hidden"))); \
+
#define VVAR(name) (vvar_ ## name)
#define TIMENS(name) (timens_ ## name)
@@ -44,12 +50,22 @@ extern char __vvar_page;
type name[CS_BASES] \
__attribute__((section(".vvar_" #name), aligned(16))) __visible
+#define DEFINE_VVAR_SINGLE(type, name) \
+ type name \
+ __attribute__((section(".vvar_" #name), aligned(16))) __visible
+
#endif
/* DECLARE_VVAR(offset, type, name) */
DECLARE_VVAR(128, struct vdso_data, _vdso_data)
+#if !defined(_SINGLE_DATA)
+#define _SINGLE_DATA
+DECLARE_VVAR_SINGLE(640, struct vdso_rng_data, _vdso_rng_data)
+#endif
+
#undef DECLARE_VVAR
+#undef DECLARE_VVAR_SINGLE
#endif
diff --git a/tools/testing/selftests/vDSO/.gitignore b/tools/testing/selftests/vDSO/.gitignore
index 7dbfdec53f3d..30d5c8f0e5c7 100644
--- a/tools/testing/selftests/vDSO/.gitignore
+++ b/tools/testing/selftests/vDSO/.gitignore
@@ -7,3 +7,4 @@ vdso_test_gettimeofday
vdso_test_getcpu
vdso_standalone_test_x86
vdso_test_getrandom
+vdso_test_chacha
diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index a33b4d200a32..7d59b7bc6ace 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -3,6 +3,7 @@ include ../lib.mk
uname_M := $(shell uname -m 2>/dev/null || echo not)
ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
+SODIUM := $(shell pkg-config --libs libsodium 2>/dev/null)
TEST_GEN_PROGS := $(OUTPUT)/vdso_test_gettimeofday $(OUTPUT)/vdso_test_getcpu
TEST_GEN_PROGS += $(OUTPUT)/vdso_test_abi
@@ -12,9 +13,17 @@ TEST_GEN_PROGS += $(OUTPUT)/vdso_standalone_test_x86
endif
TEST_GEN_PROGS += $(OUTPUT)/vdso_test_correctness
TEST_GEN_PROGS += $(OUTPUT)/vdso_test_getrandom
+ifeq ($(uname_M),x86_64)
+ifneq ($(SODIUM),)
+TEST_GEN_PROGS += $(OUTPUT)/vdso_test_chacha
+endif
+endif
CFLAGS := -std=gnu99
CFLAGS_vdso_standalone_test_x86 := -nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector
+CFLAGS_vdso_test_chacha := $(SODIUM) -idirafter $(top_srcdir)/include -idirafter \
+ $(top_srcdir)/arch/$(ARCH)/include -idirafter include \
+ -D__ASSEMBLY__ -DBULID_VDSO -DCONFIG_FUNCTION_ALIGNMENT=0 -Wa,--noexecstack
LDFLAGS_vdso_test_correctness := -ldl
ifeq ($(CONFIG_X86_32),y)
LDLIBS += -lgcc_s
@@ -35,3 +44,9 @@ $(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c
-o $@ \
$(LDFLAGS_vdso_test_correctness)
$(OUTPUT)/vdso_test_getrandom: parse_vdso.c
+$(OUTPUT)/vdso_test_chacha: CFLAGS += $(CFLAGS_vdso_test_chacha)
+$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/arch/$(ARCH)/entry/vdso/vgetrandom-chacha.S
+$(OUTPUT)/vdso_test_chacha: include/asm/rwonce.h
+include/asm/rwonce.h:
+ mkdir -p include/asm
+ touch $@
diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c
new file mode 100644
index 000000000000..e38f44e5f803
--- /dev/null
+++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include <sodium/crypto_stream_chacha20.h>
+#include <sys/random.h>
+#include <string.h>
+#include <stdint.h>
+#include "../kselftest.h"
+
+extern void __arch_chacha20_blocks_nostack(uint8_t *dst_bytes, const uint8_t *key, uint32_t *counter, size_t nblocks);
+
+int main(int argc, char *argv[])
+{
+ enum { TRIALS = 1000, BLOCKS = 128, BLOCK_SIZE = 64 };
+ static const uint8_t nonce[8] = { 0 };
+ uint32_t counter[2];
+ uint8_t key[32];
+ uint8_t output1[BLOCK_SIZE * BLOCKS], output2[BLOCK_SIZE * BLOCKS];
+
+ ksft_print_header();
+ ksft_set_plan(1);
+
+ for (unsigned int trial = 0; trial < TRIALS; ++trial) {
+ if (getrandom(key, sizeof(key), 0) != sizeof(key)) {
+ printf("getrandom() failed!\n");
+ return KSFT_SKIP;
+ }
+ crypto_stream_chacha20(output1, sizeof(output1), nonce, key);
+ for (unsigned int split = 0; split < BLOCKS; ++split) {
+ memset(output2, 'X', sizeof(output2));
+ memset(counter, 0, sizeof(counter));
+ if (split)
+ __arch_chacha20_blocks_nostack(output2, key, counter, split);
+ __arch_chacha20_blocks_nostack(output2 + split * BLOCK_SIZE, key, counter, BLOCKS - split);
+ if (memcmp(output1, output2, sizeof(output1)))
+ return KSFT_FAIL;
+ }
+ }
+ ksft_test_result_pass("chacha: PASS\n");
+ return KSFT_PASS;
+}
--
2.45.2
^ permalink raw reply related
* [PATCH v18 4/5] random: introduce generic vDSO getrandom() implementation
From: Jason A. Donenfeld @ 2024-06-20 0:53 UTC (permalink / raw)
To: linux-kernel, patches, tglx
Cc: Jason A. Donenfeld, linux-crypto, linux-api, x86,
Greg Kroah-Hartman, Adhemerval Zanella Netto, Carlos O'Donell,
Florian Weimer, Arnd Bergmann, Jann Horn, Christian Brauner,
David Hildenbrand
In-Reply-To: <20240620005339.1273434-1-Jason@zx2c4.com>
Provide a generic C vDSO getrandom() implementation, which operates on
an opaque state returned by vgetrandom_alloc() and produces random bytes
the same way as getrandom(). This has the following API signature:
ssize_t vgetrandom(void *buffer, size_t len, unsigned int flags,
void *opaque_state, size_t opaque_len);
The return value and the first three arguments are the same as ordinary
getrandom(), while the last two arguments are a pointer to the opaque
allocated state and its size. Were all five arguments passed to the
getrandom() syscall, nothing different would happen, and the functions
would have the exact same behavior.
The actual vDSO RNG algorithm implemented is the same one implemented by
drivers/char/random.c, using the same fast-erasure techniques as that.
Should the in-kernel implementation change, so too will the vDSO one.
It requires an implementation of ChaCha20 that does not use any stack,
in order to maintain forward secrecy if a multi-threaded program forks
(though this does not account for a similar issue with SA_SIGINFO
copying registers to the stack), so this is left as an
architecture-specific fill-in. Stack-less ChaCha20 is an easy algorithm
to implement on a variety of architectures, so this shouldn't be too
onerous.
Initially, the state is keyless, and so the first call makes a
getrandom() syscall to generate that key, and then uses it for
subsequent calls. By keeping track of a generation counter, it knows
when its key is invalidated and it should fetch a new one using the
syscall. Later, more than just a generation counter might be used.
Since MADV_WIPEONFORK is set on the opaque state, the key and related
state is wiped during a fork(), so secrets don't roll over into new
processes, and the same state doesn't accidentally generate the same
random stream. The generation counter, as well, is always >0, so that
the 0 counter is a useful indication of a fork() or otherwise
uninitialized state.
If the kernel RNG is not yet initialized, then the vDSO always calls the
syscall, because that behavior cannot be emulated in userspace, but
fortunately that state is short lived and only during early boot. If it
has been initialized, then there is no need to inspect the `flags`
argument, because the behavior does not change post-initialization
regardless of the `flags` value.
Since the opaque state passed to it is mutated, vDSO getrandom() is not
reentrant, when used with the same opaque state, which libc should be
mindful of.
vgetrandom_alloc() and vDSO getrandom() provide the ability for
userspace to generate random bytes quickly and safely, and are intended
to be integrated into libc's thread management. As an illustrative
example, together with the example code from "random: add
vgetrandom_alloc() syscall", the following code might be used to do the
same outside of libc. In a libc, only the non-static vgetrandom()
function at the end would be exported as part of a getrandom()
implementations, and the various pthread-isms are expected to be elided
into libc internals.
static struct {
ssize_t(*fn)(void *, size_t, unsigned long, void *, size_t);
pthread_key_t key;
pthread_once_t initialized;
} grnd_ctx = {
.initialized = PTHREAD_ONCE_INIT
};
static void vgetrandom_init(void)
{
if (pthread_key_create(&grnd_ctx.key, vgetrandom_put_state) != 0)
return;
grnd_ctx.fn = vdso_sym("LINUX_2.6", "__vdso_getrandom");
}
ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
{
void *state;
pthread_once(&grnd_ctx.initialized, vgetrandom_init);
if (!grnd_ctx.fn)
return getrandom(buf, len, flags);
state = pthread_getspecific(grnd_ctx.key);
if (!state) {
state = vgetrandom_get_state();
if (pthread_setspecific(grnd_ctx.key, state) != 0) {
vgetrandom_put_state(state);
state = NULL;
}
if (!state)
return getrandom(buf, len, flags);
}
return grnd_ctx.fn(buf, len, flags, state, grnd_allocator.size_per_each);
}
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
MAINTAINERS | 1 +
drivers/char/random.c | 13 +
include/vdso/datapage.h | 11 +
include/vdso/getrandom.h | 34 +-
lib/vdso/getrandom.c | 236 ++++++++++++++
tools/testing/selftests/vDSO/.gitignore | 1 +
tools/testing/selftests/vDSO/Makefile | 2 +
.../selftests/vDSO/vdso_test_getrandom.c | 293 ++++++++++++++++++
8 files changed, 589 insertions(+), 2 deletions(-)
create mode 100644 lib/vdso/getrandom.c
create mode 100644 tools/testing/selftests/vDSO/vdso_test_getrandom.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 8480c4c39915..6fecb837b24b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18748,6 +18748,7 @@ F: Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml
F: drivers/char/random.c
F: drivers/virt/vmgenid.c
F: include/vdso/getrandom.h
+F: lib/vdso/getrandom.c
RAPIDIO SUBSYSTEM
M: Matt Porter <mporter@kernel.crashing.org>
diff --git a/drivers/char/random.c b/drivers/char/random.c
index ccb35f390c85..ae458591caed 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -60,6 +60,7 @@
#include <crypto/blake2s.h>
#ifdef CONFIG_VDSO_GETRANDOM
#include <vdso/getrandom.h>
+#include <vdso/datapage.h>
#endif
#include <asm/archrandom.h>
#include <asm/processor.h>
@@ -404,6 +405,15 @@ static void crng_reseed(struct work_struct *work)
if (next_gen == ULONG_MAX)
++next_gen;
WRITE_ONCE(base_crng.generation, next_gen);
+#ifdef CONFIG_VDSO_GETRANDOM
+ /* base_crng.generation's invalid value is ULONG_MAX, while
+ * _vdso_rng_data.generation's invalid value is 0, so add one to the
+ * former to arrive at the latter. Use smp_store_release so that this
+ * is ordered with the write above to base_crng.generation. Pairs with
+ * the smp_rmb() before the syscall in the vDSO code.
+ */
+ smp_store_release(&_vdso_rng_data.generation, next_gen + 1);
+#endif
if (!static_branch_likely(&crng_is_ready))
crng_init = CRNG_READY;
spin_unlock_irqrestore(&base_crng.lock, flags);
@@ -854,6 +864,9 @@ static void __cold _credit_init_bits(size_t bits)
if (static_key_initialized && system_unbound_wq)
queue_work(system_unbound_wq, &set_ready);
atomic_notifier_call_chain(&random_ready_notifier, 0, NULL);
+#ifdef CONFIG_VDSO_GETRANDOM
+ WRITE_ONCE(_vdso_rng_data.is_ready, true);
+#endif
wake_up_interruptible(&crng_init_wait);
kill_fasync(&fasync, SIGIO, POLL_IN);
pr_notice("crng init done\n");
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index d04d394db064..05e5787beb73 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -113,6 +113,16 @@ struct vdso_data {
struct arch_vdso_data arch_data;
};
+/**
+ * struct vdso_rng_data - vdso RNG state information
+ * @generation: counter representing the number of RNG reseeds
+ * @is_ready: boolean signaling whether the RNG is initialized
+ */
+struct vdso_rng_data {
+ u64 generation;
+ u8 is_ready;
+};
+
/*
* We use the hidden visibility to prevent the compiler from generating a GOT
* relocation. Not only is going through a GOT useless (the entry couldn't and
@@ -124,6 +134,7 @@ struct vdso_data {
*/
extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
extern struct vdso_data _timens_data[CS_BASES] __attribute__((visibility("hidden")));
+extern struct vdso_rng_data _vdso_rng_data __attribute__((visibility("hidden")));
/**
* union vdso_data_store - Generic vDSO data page
diff --git a/include/vdso/getrandom.h b/include/vdso/getrandom.h
index 69037519d20b..84f523149d5d 100644
--- a/include/vdso/getrandom.h
+++ b/include/vdso/getrandom.h
@@ -6,11 +6,41 @@
#ifndef _VDSO_GETRANDOM_H
#define _VDSO_GETRANDOM_H
+#include <linux/types.h>
+
+#define CHACHA_KEY_SIZE 32
+#define CHACHA_BLOCK_SIZE 64
+
/**
* struct vgetrandom_state - State used by vDSO getrandom() and allocated by vgetrandom_alloc().
*
- * Currently empty, as the vDSO getrandom() function has not yet been implemented.
+ * @batch: One and a half ChaCha20 blocks of buffered RNG output.
+ *
+ * @key: Key to be used for generating next batch.
+ *
+ * @batch_key: Union of the prior two members, which is exactly two full
+ * ChaCha20 blocks in size, so that @batch and @key can be filled
+ * together.
+ *
+ * @generation: Snapshot of @rng_info->generation in the vDSO data page at
+ * the time @key was generated.
+ *
+ * @pos: Offset into @batch of the next available random byte.
+ *
+ * @in_use: Reentrancy guard for reusing a state within the same thread
+ * due to signal handlers.
*/
-struct vgetrandom_state { int placeholder; };
+struct vgetrandom_state {
+ union {
+ struct {
+ u8 batch[CHACHA_BLOCK_SIZE * 3 / 2];
+ u32 key[CHACHA_KEY_SIZE / sizeof(u32)];
+ };
+ u8 batch_key[CHACHA_BLOCK_SIZE * 2];
+ };
+ u64 generation;
+ u8 pos;
+ bool in_use;
+};
#endif /* _VDSO_GETRANDOM_H */
diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c
new file mode 100644
index 000000000000..5efcd0d0af6b
--- /dev/null
+++ b/lib/vdso/getrandom.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include <linux/cache.h>
+#include <linux/kernel.h>
+#include <linux/time64.h>
+#include <vdso/datapage.h>
+#include <vdso/getrandom.h>
+#include <asm/vdso/getrandom.h>
+#include <asm/vdso/vsyscall.h>
+#include <asm/unaligned.h>
+
+#define MEMCPY_AND_ZERO_SRC(type, dst, src, len) do { \
+ while (len >= sizeof(type)) { \
+ __put_unaligned_t(type, __get_unaligned_t(type, src), dst); \
+ __put_unaligned_t(type, 0, src); \
+ dst += sizeof(type); \
+ src += sizeof(type); \
+ len -= sizeof(type); \
+ } \
+} while (0)
+
+static void memcpy_and_zero_src(void *dst, void *src, size_t len)
+{
+ if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
+ if (IS_ENABLED(CONFIG_64BIT))
+ MEMCPY_AND_ZERO_SRC(u64, dst, src, len);
+ MEMCPY_AND_ZERO_SRC(u32, dst, src, len);
+ MEMCPY_AND_ZERO_SRC(u16, dst, src, len);
+ }
+ MEMCPY_AND_ZERO_SRC(u8, dst, src, len);
+}
+
+/**
+ * __cvdso_getrandom_data - Generic vDSO implementation of getrandom() syscall.
+ * @rng_info: Describes state of kernel RNG, memory shared with kernel.
+ * @buffer: Destination buffer to fill with random bytes.
+ * @len: Size of @buffer in bytes.
+ * @flags: Zero or more GRND_* flags.
+ * @opaque_state: Pointer to an opaque state area.
+ * @opaque_len: Length of opaque state area.
+ *
+ * This implements a "fast key erasure" RNG using ChaCha20, in the same way that the kernel's
+ * getrandom() syscall does. It periodically reseeds its key from the kernel's RNG, at the same
+ * schedule that the kernel's RNG is reseeded. If the kernel's RNG is not ready, then this always
+ * calls into the syscall.
+ *
+ * @opaque_state *must* be allocated using the vgetrandom_alloc() syscall. Unless external locking
+ * is used, one state must be allocated per thread, as it is not safe to call this function
+ * concurrently with the same @opaque_state. However, it is safe to call this using the same
+ * @opaque_state that is shared between main code and signal handling code, within the same thread.
+ *
+ * Returns: The number of random bytes written to @buffer, or a negative value indicating an error.
+ */
+static __always_inline ssize_t
+__cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_t len,
+ unsigned int flags, void *opaque_state, size_t opaque_len)
+{
+ ssize_t ret = min_t(size_t, INT_MAX & PAGE_MASK /* = MAX_RW_COUNT */, len);
+ struct vgetrandom_state *state = opaque_state;
+ size_t batch_len, nblocks, orig_len = len;
+ bool in_use, have_retried = false;
+ unsigned long current_generation;
+ void *orig_buffer = buffer;
+ u32 counter[2] = { 0 };
+
+ /* The state must not straddle a page, since pages can be zeroed at any time. */
+ if (unlikely(((unsigned long)opaque_state & ~PAGE_MASK) + sizeof(*state) > PAGE_SIZE))
+ return -EFAULT;
+
+ /* If the caller passes the wrong size, which might happen due to CRIU, fallback. */
+ if (unlikely(opaque_len != sizeof(*state)))
+ goto fallback_syscall;
+
+ /*
+ * If the kernel's RNG is not yet ready, then it's not possible to provide random bytes from
+ * userspace, because A) the various @flags require this to block, or not, depending on
+ * various factors unavailable to userspace, and B) the kernel's behavior before the RNG is
+ * ready is to reseed from the entropy pool at every invocation.
+ */
+ if (unlikely(!READ_ONCE(rng_info->is_ready)))
+ goto fallback_syscall;
+
+ /*
+ * This condition is checked after @rng_info->is_ready, because before the kernel's RNG is
+ * initialized, the @flags parameter may require this to block or return an error, even when
+ * len is zero.
+ */
+ if (unlikely(!len))
+ return 0;
+
+ /*
+ * @state->in_use is basic reentrancy protection against this running in a signal handler
+ * with the same @opaque_state, but obviously not atomic wrt multiple CPUs or more than one
+ * level of reentrancy. If a signal interrupts this after reading @state->in_use, but before
+ * writing @state->in_use, there is still no race, because the signal handler will run to
+ * its completion before returning execution.
+ */
+ in_use = READ_ONCE(state->in_use);
+ if (unlikely(in_use))
+ /* The syscall simply fills the buffer and does not touch @state, so fallback. */
+ goto fallback_syscall;
+ WRITE_ONCE(state->in_use, true);
+
+retry_generation:
+ /*
+ * @rng_info->generation must always be read here, as it serializes @state->key with the
+ * kernel's RNG reseeding schedule.
+ */
+ current_generation = READ_ONCE(rng_info->generation);
+
+ /*
+ * If @state->generation doesn't match the kernel RNG's generation, then it means the
+ * kernel's RNG has reseeded, and so @state->key is reseeded as well.
+ */
+ if (unlikely(state->generation != current_generation)) {
+ /*
+ * Write the generation before filling the key, in case of fork. If there is a fork
+ * just after this line, the parent and child will get different random bytes from
+ * the syscall, which is good. However, were this line to occur after the getrandom
+ * syscall, then both child and parent could have the same bytes and the same
+ * generation counter, so the fork would not be detected. Therefore, write
+ * @state->generation before the call to the getrandom syscall.
+ */
+ WRITE_ONCE(state->generation, current_generation);
+
+ /*
+ * Prevent the syscall from being reordered wrt current_generation. Pairs with the
+ * smp_store_release(&_vdso_rng_data.generation) in random.c.
+ */
+ smp_rmb();
+
+ /* Reseed @state->key using fresh bytes from the kernel. */
+ if (getrandom_syscall(state->key, sizeof(state->key), 0) != sizeof(state->key)) {
+ /*
+ * If the syscall failed to refresh the key, then @state->key is now
+ * invalid, so invalidate the generation so that it is not used again, and
+ * fallback to using the syscall entirely.
+ */
+ WRITE_ONCE(state->generation, 0);
+
+ /*
+ * Set @state->in_use to false only after the last write to @state in the
+ * line above.
+ */
+ WRITE_ONCE(state->in_use, false);
+
+ goto fallback_syscall;
+ }
+
+ /*
+ * Set @state->pos to beyond the end of the batch, so that the batch is refilled
+ * using the new key.
+ */
+ state->pos = sizeof(state->batch);
+ }
+
+ /* Set len to the total amount of bytes that this function is allowed to read, ret. */
+ len = ret;
+more_batch:
+ /*
+ * First use bytes out of @state->batch, which may have been filled by the last call to this
+ * function.
+ */
+ batch_len = min_t(size_t, sizeof(state->batch) - state->pos, len);
+ if (batch_len) {
+ /* Zeroing at the same time as memcpying helps preserve forward secrecy. */
+ memcpy_and_zero_src(buffer, state->batch + state->pos, batch_len);
+ state->pos += batch_len;
+ buffer += batch_len;
+ len -= batch_len;
+ }
+
+ if (!len) {
+ /* Prevent the loop from being reordered wrt ->generation. */
+ barrier();
+
+ /*
+ * Since @rng_info->generation will never be 0, re-read @state->generation, rather
+ * than using the local current_generation variable, to learn whether a fork
+ * occurred or if @state was zeroed due to memory pressure. Primarily, though, this
+ * indicates whether the kernel's RNG has reseeded, in which case generate a new key
+ * and start over.
+ */
+ if (unlikely(READ_ONCE(state->generation) != READ_ONCE(rng_info->generation))) {
+ /*
+ * Prevent this from looping forever in case of low memory or racing with a
+ * user force-reseeding the kernel's RNG using the ioctl.
+ */
+ if (have_retried) {
+ WRITE_ONCE(state->in_use, false);
+ goto fallback_syscall;
+ }
+
+ have_retried = true;
+ buffer = orig_buffer;
+ goto retry_generation;
+ }
+
+ /*
+ * Set @state->in_use to false only when there will be no more reads or writes of
+ * @state.
+ */
+ WRITE_ONCE(state->in_use, false);
+ return ret;
+ }
+
+ /* Generate blocks of RNG output directly into @buffer while there's enough room left. */
+ nblocks = len / CHACHA_BLOCK_SIZE;
+ if (nblocks) {
+ __arch_chacha20_blocks_nostack(buffer, state->key, counter, nblocks);
+ buffer += nblocks * CHACHA_BLOCK_SIZE;
+ len -= nblocks * CHACHA_BLOCK_SIZE;
+ }
+
+ BUILD_BUG_ON(sizeof(state->batch_key) % CHACHA_BLOCK_SIZE != 0);
+
+ /* Refill the batch and overwrite the key, in order to preserve forward secrecy. */
+ __arch_chacha20_blocks_nostack(state->batch_key, state->key, counter,
+ sizeof(state->batch_key) / CHACHA_BLOCK_SIZE);
+
+ /* Since the batch was just refilled, set the position back to 0 to indicate a full batch. */
+ state->pos = 0;
+ goto more_batch;
+
+fallback_syscall:
+ return getrandom_syscall(orig_buffer, orig_len, flags);
+}
+
+static __always_inline ssize_t
+__cvdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len)
+{
+ return __cvdso_getrandom_data(__arch_get_vdso_rng_data(), buffer, len, flags, opaque_state, opaque_len);
+}
diff --git a/tools/testing/selftests/vDSO/.gitignore b/tools/testing/selftests/vDSO/.gitignore
index a8dc51af5a9c..7dbfdec53f3d 100644
--- a/tools/testing/selftests/vDSO/.gitignore
+++ b/tools/testing/selftests/vDSO/.gitignore
@@ -6,3 +6,4 @@ vdso_test_correctness
vdso_test_gettimeofday
vdso_test_getcpu
vdso_standalone_test_x86
+vdso_test_getrandom
diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile
index d53a4d8008f9..a33b4d200a32 100644
--- a/tools/testing/selftests/vDSO/Makefile
+++ b/tools/testing/selftests/vDSO/Makefile
@@ -11,6 +11,7 @@ ifeq ($(ARCH),$(filter $(ARCH),x86 x86_64))
TEST_GEN_PROGS += $(OUTPUT)/vdso_standalone_test_x86
endif
TEST_GEN_PROGS += $(OUTPUT)/vdso_test_correctness
+TEST_GEN_PROGS += $(OUTPUT)/vdso_test_getrandom
CFLAGS := -std=gnu99
CFLAGS_vdso_standalone_test_x86 := -nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector
@@ -33,3 +34,4 @@ $(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c
vdso_test_correctness.c \
-o $@ \
$(LDFLAGS_vdso_test_correctness)
+$(OUTPUT)/vdso_test_getrandom: parse_vdso.c
diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
new file mode 100644
index 000000000000..a4315eb4d075
--- /dev/null
+++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#include <assert.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/auxv.h>
+#include <sys/mman.h>
+#include <sys/random.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <linux/const.h>
+
+#include "../kselftest.h"
+#include "parse_vdso.h"
+
+#ifndef timespecsub
+#define timespecsub(tsp, usp, vsp) \
+ do { \
+ (vsp)->tv_sec = (tsp)->tv_sec - (usp)->tv_sec; \
+ (vsp)->tv_nsec = (tsp)->tv_nsec - (usp)->tv_nsec; \
+ if ((vsp)->tv_nsec < 0) { \
+ (vsp)->tv_sec--; \
+ (vsp)->tv_nsec += 1000000000L; \
+ } \
+ } while (0)
+#endif
+
+#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
+
+static void *vgetrandom_alloc(unsigned int *num, unsigned int *size_per_each)
+{
+ enum { __NR_vgetrandom_alloc = 463 };
+ *size_per_each = 0;
+ return (void *)syscall(__NR_vgetrandom_alloc, num, size_per_each, 0, 0);
+}
+
+static struct {
+ pthread_mutex_t lock;
+ void **states;
+ size_t len, cap, size_per_each;
+} grnd_allocator = {
+ .lock = PTHREAD_MUTEX_INITIALIZER
+};
+
+static void *vgetrandom_get_state(void)
+{
+ void *state = NULL;
+
+ pthread_mutex_lock(&grnd_allocator.lock);
+ if (!grnd_allocator.len) {
+ size_t new_cap;
+ size_t page_size = getpagesize();
+ unsigned int num = sysconf(_SC_NPROCESSORS_ONLN); /* Just a decent heuristic. */
+ unsigned int size_per_each;
+ void *new_block = vgetrandom_alloc(&num, &size_per_each);
+ void *new_states;
+
+ if (new_block == MAP_FAILED)
+ goto out;
+ if (grnd_allocator.size_per_each && grnd_allocator.size_per_each != size_per_each)
+ goto unmap;
+ grnd_allocator.size_per_each = size_per_each;
+ new_cap = grnd_allocator.cap + num;
+ new_states = reallocarray(grnd_allocator.states, new_cap, sizeof(*grnd_allocator.states));
+ if (!new_states)
+ goto unmap;
+ grnd_allocator.cap = new_cap;
+ grnd_allocator.states = new_states;
+
+ for (size_t i = 0; i < num; ++i) {
+ grnd_allocator.states[i] = new_block;
+ if (((uintptr_t)new_block & (page_size - 1)) + size_per_each > page_size)
+ new_block = (void *)(((uintptr_t)new_block + page_size) & (page_size - 1));
+ else
+ new_block += size_per_each;
+ }
+ grnd_allocator.len = num;
+ goto success;
+
+ unmap:
+ munmap(new_block, DIV_ROUND_UP(num, page_size / size_per_each) * page_size);
+ goto out;
+ }
+success:
+ state = grnd_allocator.states[--grnd_allocator.len];
+
+out:
+ pthread_mutex_unlock(&grnd_allocator.lock);
+ return state;
+}
+
+static void vgetrandom_put_state(void *state)
+{
+ if (!state)
+ return;
+ pthread_mutex_lock(&grnd_allocator.lock);
+ grnd_allocator.states[grnd_allocator.len++] = state;
+ pthread_mutex_unlock(&grnd_allocator.lock);
+}
+
+static struct {
+ ssize_t(*fn)(void *, size_t, unsigned long, void *, size_t);
+ pthread_key_t key;
+ pthread_once_t initialized;
+} grnd_ctx = {
+ .initialized = PTHREAD_ONCE_INIT
+};
+
+static void vgetrandom_init(void)
+{
+ if (pthread_key_create(&grnd_ctx.key, vgetrandom_put_state) != 0)
+ return;
+ unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
+ if (!sysinfo_ehdr) {
+ printf("AT_SYSINFO_EHDR is not present!\n");
+ exit(KSFT_SKIP);
+ }
+ vdso_init_from_sysinfo_ehdr(sysinfo_ehdr);
+ grnd_ctx.fn = (__typeof__(grnd_ctx.fn))vdso_sym("LINUX_2.6", "__vdso_getrandom");
+ if (!grnd_ctx.fn) {
+ printf("__vdso_getrandom is missing!\n");
+ exit(KSFT_FAIL);
+ }
+}
+
+static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags)
+{
+ void *state;
+
+ pthread_once(&grnd_ctx.initialized, vgetrandom_init);
+ state = pthread_getspecific(grnd_ctx.key);
+ if (!state) {
+ state = vgetrandom_get_state();
+ if (pthread_setspecific(grnd_ctx.key, state) != 0) {
+ vgetrandom_put_state(state);
+ state = NULL;
+ }
+ if (!state) {
+ printf("vgetrandom_get_state failed!\n");
+ exit(KSFT_FAIL);
+ }
+ }
+ return grnd_ctx.fn(buf, len, flags, state, grnd_allocator.size_per_each);
+}
+
+enum { TRIALS = 25000000, THREADS = 256 };
+
+static void *test_vdso_getrandom(void *)
+{
+ for (size_t i = 0; i < TRIALS; ++i) {
+ unsigned int val;
+ ssize_t ret = vgetrandom(&val, sizeof(val), 0);
+ assert(ret == sizeof(val));
+ }
+ return NULL;
+}
+
+static void *test_libc_getrandom(void *)
+{
+ for (size_t i = 0; i < TRIALS; ++i) {
+ unsigned int val;
+ ssize_t ret = getrandom(&val, sizeof(val), 0);
+ assert(ret == sizeof(val));
+ }
+ return NULL;
+}
+
+static void *test_syscall_getrandom(void *)
+{
+ for (size_t i = 0; i < TRIALS; ++i) {
+ unsigned int val;
+ ssize_t ret = syscall(SYS_getrandom, &val, sizeof(val), 0);
+ assert(ret == sizeof(val));
+ }
+ return NULL;
+}
+
+static void bench_single(void)
+{
+ struct timespec start, end, diff;
+
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ test_vdso_getrandom(NULL);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+ timespecsub(&end, &start, &diff);
+ printf(" vdso: %u times in %lu.%09lu seconds\n", TRIALS, diff.tv_sec, diff.tv_nsec);
+
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ test_libc_getrandom(NULL);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+ timespecsub(&end, &start, &diff);
+ printf(" libc: %u times in %lu.%09lu seconds\n", TRIALS, diff.tv_sec, diff.tv_nsec);
+
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ test_syscall_getrandom(NULL);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+ timespecsub(&end, &start, &diff);
+ printf("syscall: %u times in %lu.%09lu seconds\n", TRIALS, diff.tv_sec, diff.tv_nsec);
+}
+
+static void bench_multi(void)
+{
+ struct timespec start, end, diff;
+ pthread_t threads[THREADS];
+
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ for (size_t i = 0; i < THREADS; ++i)
+ assert(pthread_create(&threads[i], NULL, test_vdso_getrandom, NULL) == 0);
+ for (size_t i = 0; i < THREADS; ++i)
+ pthread_join(threads[i], NULL);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+ timespecsub(&end, &start, &diff);
+ printf(" vdso: %u x %u times in %lu.%09lu seconds\n", TRIALS, THREADS, diff.tv_sec, diff.tv_nsec);
+
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ for (size_t i = 0; i < THREADS; ++i)
+ assert(pthread_create(&threads[i], NULL, test_libc_getrandom, NULL) == 0);
+ for (size_t i = 0; i < THREADS; ++i)
+ pthread_join(threads[i], NULL);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+ timespecsub(&end, &start, &diff);
+ printf(" libc: %u x %u times in %lu.%09lu seconds\n", TRIALS, THREADS, diff.tv_sec, diff.tv_nsec);
+
+ clock_gettime(CLOCK_MONOTONIC, &start);
+ for (size_t i = 0; i < THREADS; ++i)
+ assert(pthread_create(&threads[i], NULL, test_syscall_getrandom, NULL) == 0);
+ for (size_t i = 0; i < THREADS; ++i)
+ pthread_join(threads[i], NULL);
+ clock_gettime(CLOCK_MONOTONIC, &end);
+ timespecsub(&end, &start, &diff);
+ printf(" syscall: %u x %u times in %lu.%09lu seconds\n", TRIALS, THREADS, diff.tv_sec, diff.tv_nsec);
+}
+
+static void fill(void)
+{
+ uint8_t weird_size[323929];
+ for (;;)
+ vgetrandom(weird_size, sizeof(weird_size), 0);
+}
+
+static void kselftest(void)
+{
+ uint8_t weird_size[1263];
+
+ ksft_print_header();
+ ksft_set_plan(1);
+
+ for (size_t i = 0; i < 1000; ++i) {
+ ssize_t ret = vgetrandom(weird_size, sizeof(weird_size), 0);
+ if (ret != sizeof(weird_size))
+ exit(KSFT_FAIL);
+ }
+
+ ksft_test_result_pass("getrandom: PASS\n");
+ exit(KSFT_PASS);
+}
+
+static void usage(const char *argv0)
+{
+ fprintf(stderr, "Usage: %s [bench-single|bench-multi|fill]\n", argv0);
+}
+
+int main(int argc, char *argv[])
+{
+ if (argc == 1) {
+ kselftest();
+ return 0;
+ }
+
+ if (argc != 2) {
+ usage(argv[0]);
+ return 1;
+ }
+ if (!strcmp(argv[1], "bench-single"))
+ bench_single();
+ else if (!strcmp(argv[1], "bench-multi"))
+ bench_multi();
+ else if (!strcmp(argv[1], "fill"))
+ fill();
+ else {
+ usage(argv[0]);
+ return 1;
+ }
+ return 0;
+}
--
2.45.2
^ permalink raw reply related
* [PATCH v18 3/5] arch: allocate vgetrandom_alloc() syscall number
From: Jason A. Donenfeld @ 2024-06-20 0:53 UTC (permalink / raw)
To: linux-kernel, patches, tglx
Cc: Jason A. Donenfeld, linux-crypto, linux-api, x86,
Greg Kroah-Hartman, Adhemerval Zanella Netto, Carlos O'Donell,
Florian Weimer, Arnd Bergmann, Jann Horn, Christian Brauner,
David Hildenbrand, Geert Uytterhoeven
In-Reply-To: <20240620005339.1273434-1-Jason@zx2c4.com>
Add vgetrandom_alloc() as syscall 463 (or 573 on alpha) by adding it to
all of the various syscall.tbl and unistd.h files.
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
arch/alpha/kernel/syscalls/syscall.tbl | 1 +
arch/arm/tools/syscall.tbl | 1 +
arch/arm64/include/asm/unistd32.h | 2 ++
arch/m68k/kernel/syscalls/syscall.tbl | 1 +
arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
arch/mips/kernel/syscalls/syscall_o32.tbl | 1 +
arch/parisc/kernel/syscalls/syscall.tbl | 1 +
arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
arch/s390/kernel/syscalls/syscall.tbl | 1 +
arch/sh/kernel/syscalls/syscall.tbl | 1 +
arch/sparc/kernel/syscalls/syscall.tbl | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/xtensa/kernel/syscalls/syscall.tbl | 1 +
include/uapi/asm-generic/unistd.h | 5 ++++-
tools/include/uapi/asm-generic/unistd.h | 5 ++++-
tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl | 1 +
tools/perf/arch/powerpc/entry/syscalls/syscall.tbl | 1 +
tools/perf/arch/s390/entry/syscalls/syscall.tbl | 1 +
tools/perf/arch/x86/entry/syscalls/syscall_64.tbl | 1 +
22 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 74720667fe09..8c38193bf86a 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -502,3 +502,4 @@
570 common lsm_set_self_attr sys_lsm_set_self_attr
571 common lsm_list_modules sys_lsm_list_modules
572 common mseal sys_mseal
+573 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 2ed7d229c8f9..118e41178905 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -476,3 +476,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 266b96acc014..e84fa30ccd30 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -931,6 +931,8 @@ __SYSCALL(__NR_lsm_set_self_attr, sys_lsm_set_self_attr)
__SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules)
#define __NR_mseal 462
__SYSCALL(__NR_mseal, sys_mseal)
+#define __NR_vgetrandom_alloc 463
+__SYSCALL(__NR_vgetrandom_alloc, sys_vgetrandom_alloc)
/*
* Please add new compat syscalls above this comment and update
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 22a3cbd4c602..bd919d1a8231 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -462,3 +462,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 2b81a6bd78b2..d3d3c017a5bb 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -468,3 +468,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index cc869f5d5693..9b1bda3d8383 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -401,3 +401,4 @@
460 n32 lsm_set_self_attr sys_lsm_set_self_attr
461 n32 lsm_list_modules sys_lsm_list_modules
462 n32 mseal sys_mseal
+463 n32 vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 1464c6be6eb3..33710f855c46 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -377,3 +377,4 @@
460 n64 lsm_set_self_attr sys_lsm_set_self_attr
461 n64 lsm_list_modules sys_lsm_list_modules
462 n64 mseal sys_mseal
+463 n64 vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 008ebe60263e..97698956cdce 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -450,3 +450,4 @@
460 o32 lsm_set_self_attr sys_lsm_set_self_attr
461 o32 lsm_list_modules sys_lsm_list_modules
462 o32 mseal sys_mseal
+463 o32 vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index b13c21373974..5fbbb25699b9 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -461,3 +461,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 3656f1ca7a21..b1c3ae68014c 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -549,3 +549,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index bd0fee24ad10..1188429316c1 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -465,3 +465,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index bbf83a2db986..06cec74502f7 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -465,3 +465,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index ac6c281ccfe0..a3816995d08c 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -508,3 +508,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 7fd1f57ad3d3..821990638567 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -467,3 +467,4 @@
460 i386 lsm_set_self_attr sys_lsm_set_self_attr
461 i386 lsm_list_modules sys_lsm_list_modules
462 i386 mseal sys_mseal
+463 i386 vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index a396f6e6ab5b..441443ba2ae6 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -384,6 +384,7 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
#
# Due to a historical design error, certain syscalls are numbered differently
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 67083fc1b2f5..b9f64edd0b18 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -433,3 +433,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index d983c48a3b6a..e94210483f60 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -845,8 +845,11 @@ __SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules)
#define __NR_mseal 462
__SYSCALL(__NR_mseal, sys_mseal)
+#define __NR_vgetrandom_alloc 463
+__SYSCALL(__NR_vgetrandom_alloc, sys_vgetrandom_alloc)
+
#undef __NR_syscalls
-#define __NR_syscalls 463
+#define __NR_syscalls 464
/*
* 32 bit systems traditionally used different
diff --git a/tools/include/uapi/asm-generic/unistd.h b/tools/include/uapi/asm-generic/unistd.h
index d983c48a3b6a..e94210483f60 100644
--- a/tools/include/uapi/asm-generic/unistd.h
+++ b/tools/include/uapi/asm-generic/unistd.h
@@ -845,8 +845,11 @@ __SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules)
#define __NR_mseal 462
__SYSCALL(__NR_mseal, sys_mseal)
+#define __NR_vgetrandom_alloc 463
+__SYSCALL(__NR_vgetrandom_alloc, sys_vgetrandom_alloc)
+
#undef __NR_syscalls
-#define __NR_syscalls 463
+#define __NR_syscalls 464
/*
* 32 bit systems traditionally used different
diff --git a/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl b/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
index 1464c6be6eb3..33710f855c46 100644
--- a/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
+++ b/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl
@@ -377,3 +377,4 @@
460 n64 lsm_set_self_attr sys_lsm_set_self_attr
461 n64 lsm_list_modules sys_lsm_list_modules
462 n64 mseal sys_mseal
+463 n64 vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
index 3656f1ca7a21..b1c3ae68014c 100644
--- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
@@ -549,3 +549,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/tools/perf/arch/s390/entry/syscalls/syscall.tbl b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
index bd0fee24ad10..1188429316c1 100644
--- a/tools/perf/arch/s390/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
@@ -465,3 +465,4 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc sys_vgetrandom_alloc
diff --git a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
index a396f6e6ab5b..441443ba2ae6 100644
--- a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl
@@ -384,6 +384,7 @@
460 common lsm_set_self_attr sys_lsm_set_self_attr
461 common lsm_list_modules sys_lsm_list_modules
462 common mseal sys_mseal
+463 common vgetrandom_alloc sys_vgetrandom_alloc
#
# Due to a historical design error, certain syscalls are numbered differently
--
2.45.2
^ permalink raw reply related
* [PATCH v18 2/5] random: add vgetrandom_alloc() syscall
From: Jason A. Donenfeld @ 2024-06-20 0:53 UTC (permalink / raw)
To: linux-kernel, patches, tglx
Cc: Jason A. Donenfeld, linux-crypto, linux-api, x86,
Greg Kroah-Hartman, Adhemerval Zanella Netto, Carlos O'Donell,
Florian Weimer, Arnd Bergmann, Jann Horn, Christian Brauner,
David Hildenbrand
In-Reply-To: <20240620005339.1273434-1-Jason@zx2c4.com>
The vDSO getrandom() works over an opaque per-thread state of an
unexported size, which must be marked VM_WIPEONFORK, VM_DONTDUMP,
VM_NORESERVE, and VM_DROPPABLE for proper operation. Over time, the
nuances of these allocations may change or grow or even differ based on
architectural features.
The syscall has the signature:
void *vgetrandom_alloc(unsigned int *num, unsigned int *size_per_each,
unsigned long addr, unsigned int flags);
This takes a hinted number of opaque states in `num`, and returns a
pointer to an array of opaque states, the number actually allocated back
in `num`, and the size in bytes of each one in `size_per_each`, enabling
a libc to slice up the returned array into a state per each thread,
while ensuring that no single state straddles a page boundary. (The
`flags` and `addr` arguments, as well as the `*size_per_each` input
value, are reserved for the future and are forced to be zero zero for
now.)
Libc is expected to allocate a chunk of these on first use, and then
dole them out to threads as they're created, allocating more when
needed. The returned address of the first state may be passed to
munmap(2) with a length of `DIV_ROUND_UP(num, PAGE_SIZE / size_per_each)
* PAGE_SIZE`, in order to deallocate the memory.
We very intentionally do *not* leave state allocation for vDSO
getrandom() up to userspace itself, but rather provide this new syscall
for such allocations. vDSO getrandom() must not store its state in just
any old memory address, but rather just ones that the kernel specially
allocates for it, leaving the particularities of those allocations up to
the kernel.
The allocation of states is intended to be integrated into libc's thread
management. As an illustrative example, the following code might be used
to do the same outside of libc. Though, vgetrandom_alloc() is not
expected to be exposed outside of libc, and the pthread usage here is
expected to be elided into libc internals. This allocation scheme is
very naive and does not shrink; other implementations may choose to be
more complex.
static void *vgetrandom_alloc(unsigned int *num, unsigned int *size_per_each)
{
*size_per_each = 0; /* Must be zero on input. */
return (void *)syscall(__NR_vgetrandom_alloc, &num, &size_per_each,
0 /* reserved @addr */, 0 /* reserved @flags */);
}
static struct {
pthread_mutex_t lock;
void **states;
size_t len, cap, size_per_each;
} grnd_allocator = {
.lock = PTHREAD_MUTEX_INITIALIZER
};
static void *vgetrandom_get_state(void)
{
void *state = NULL;
pthread_mutex_lock(&grnd_allocator.lock);
if (!grnd_allocator.len) {
size_t new_cap;
size_t page_size = getpagesize();
unsigned int num = sysconf(_SC_NPROCESSORS_ONLN); /* Could be arbitrary, just a hint. */
unsigned int size_per_each;
void *new_block = vgetrandom_alloc(&num, &size_per_each);
void *new_states;
if (new_block == MAP_FAILED)
goto out;
if (grnd_allocator.size_per_each && grnd_allocator.size_per_each != size_per_each)
goto unmap;
grnd_allocator.size_per_each = size_per_each;
new_cap = grnd_allocator.cap + num;
new_states = reallocarray(grnd_allocator.states, new_cap, sizeof(*grnd_allocator.states));
if (!new_states)
goto unmap;
grnd_allocator.cap = new_cap;
grnd_allocator.states = new_states;
for (size_t i = 0; i < num; ++i) {
grnd_allocator.states[i] = new_block;
if (((uintptr_t)new_block & (page_size - 1)) + size_per_each > page_size)
new_block = (void *)(((uintptr_t)new_block + page_size) & (page_size - 1));
else
new_block += size_per_each;
}
grnd_allocator.len = num;
goto success;
unmap:
munmap(new_block, DIV_ROUND_UP(num, page_size / size_per_each) * page_size);
goto out;
}
success:
state = grnd_allocator.states[--grnd_allocator.len];
out:
pthread_mutex_unlock(&grnd_allocator.lock);
return state;
}
static void vgetrandom_put_state(void *state)
{
if (!state)
return;
pthread_mutex_lock(&grnd_allocator.lock);
grnd_allocator.states[grnd_allocator.len++] = state;
pthread_mutex_unlock(&grnd_allocator.lock);
}
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
MAINTAINERS | 1 +
drivers/char/random.c | 135 ++++++++++++++++++++++++++++++++++++++-
include/linux/syscalls.h | 3 +
include/vdso/getrandom.h | 16 +++++
kernel/sys_ni.c | 3 +
lib/vdso/Kconfig | 6 ++
6 files changed, 163 insertions(+), 1 deletion(-)
create mode 100644 include/vdso/getrandom.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 8aa17e515ef3..8480c4c39915 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18747,6 +18747,7 @@ T: git https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git
F: Documentation/devicetree/bindings/rng/microsoft,vmgenid.yaml
F: drivers/char/random.c
F: drivers/virt/vmgenid.c
+F: include/vdso/getrandom.h
RAPIDIO SUBSYSTEM
M: Matt Porter <mporter@kernel.crashing.org>
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 2597cb43f438..ccb35f390c85 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/*
- * Copyright (C) 2017-2022 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ * Copyright (C) 2017-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
* Copyright Matt Mackall <mpm@selenic.com>, 2003, 2004, 2005
* Copyright Theodore Ts'o, 1994, 1995, 1996, 1997, 1998, 1999. All rights reserved.
*
@@ -8,6 +8,7 @@
* into roughly six sections, each with a section header:
*
* - Initialization and readiness waiting.
+ * - vDSO support helpers.
* - Fast key erasure RNG, the "crng".
* - Entropy accumulation and extraction routines.
* - Entropy collection routines.
@@ -39,6 +40,7 @@
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
+#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
@@ -56,6 +58,9 @@
#include <linux/sched/isolation.h>
#include <crypto/chacha.h>
#include <crypto/blake2s.h>
+#ifdef CONFIG_VDSO_GETRANDOM
+#include <vdso/getrandom.h>
+#endif
#include <asm/archrandom.h>
#include <asm/processor.h>
#include <asm/irq.h>
@@ -169,6 +174,134 @@ int __cold execute_with_initialized_rng(struct notifier_block *nb)
__func__, (void *)_RET_IP_, crng_init)
+
+/********************************************************************
+ *
+ * vDSO support helpers.
+ *
+ * The actual vDSO function is defined over in lib/vdso/getrandom.c,
+ * but this section contains the kernel-mode helpers to support that.
+ *
+ ********************************************************************/
+
+#ifdef CONFIG_VDSO_GETRANDOM
+/**
+ * sys_vgetrandom_alloc - Allocate opaque states for use with vDSO getrandom().
+ *
+ * @num: On input, a pointer to a suggested hint of how many states to
+ * allocate, and on return the number of states actually allocated.
+ *
+ * @size_per_each: On input, must be zero. On return, the size of each state allocated,
+ * so that the caller can split up the returned allocation into
+ * individual states.
+ *
+ * @addr: Reserved, must be zero.
+ *
+ * @flags: Reserved, must be zero.
+ *
+ * The getrandom() vDSO function in userspace requires an opaque state, which
+ * this function allocates by mapping a certain number of special pages into
+ * the calling process. It takes a hint as to the number of opaque states
+ * desired, and provides the caller with the number of opaque states actually
+ * allocated, the size of each one in bytes, and the address of the first
+ * state, which may be split up into @num states of @size_per_each bytes each,
+ * by adding @size_per_each to the returned first state @num times, while
+ * ensuring that no single state straddles a page boundary.
+ *
+ * Returns the address of the first state in the allocation on success, or a
+ * negative error value on failure.
+ *
+ * The returned address of the first state may be passed to munmap(2) with a
+ * length of `DIV_ROUND_UP(num, PAGE_SIZE / size_per_each) * PAGE_SIZE`, in
+ * order to deallocate the memory, after which it is invalid to pass it to vDSO
+ * getrandom().
+ *
+ * States allocated by this function must not be dereferenced, written, read,
+ * or otherwise manipulated. The *only* supported operations are:
+ * - Splitting up the states in intervals of @size_per_each, no more than
+ * @num times from the first state, while ensuring that no single state
+ * straddles a page boundary.
+ * - Passing a state to the getrandom() vDSO function's @opaque_state
+ * parameter, but not passing the same state at the same time to two such
+ * calls.
+ * - Passing the first state and the total length to munmap(2), as described
+ * above.
+ * All other uses are undefined behavior, which is subject to change or removal.
+ */
+SYSCALL_DEFINE4(vgetrandom_alloc, unsigned int __user *, num,
+ unsigned int __user *, size_per_each, unsigned long, addr,
+ unsigned int, flags)
+{
+ size_t state_size, alloc_size, num_states;
+ unsigned long pages_addr, populate;
+ unsigned int num_hint;
+ vm_flags_t vm_flags;
+ int ret;
+
+ /*
+ * @flags and @addr are currently unused, so in order to reserve them
+ * for the future, force them to be set to zero by current callers.
+ */
+ if (flags || addr)
+ return -EINVAL;
+
+ /*
+ * Also enforce that *size_per_each is zero on input, in case this becomes
+ * useful later on.
+ */
+ if (get_user(num_hint, size_per_each))
+ return -EFAULT;
+ if (num_hint)
+ return -EINVAL;
+
+ if (get_user(num_hint, num))
+ return -EFAULT;
+
+ state_size = sizeof(struct vgetrandom_state);
+ num_states = clamp_t(size_t, num_hint, 1, (SIZE_MAX & PAGE_MASK) / state_size);
+ alloc_size = PAGE_ALIGN(num_states * state_size);
+ /*
+ * States cannot straddle page boundaries, so calculate the number of
+ * states that can fit inside of a page without being split, and then
+ * multiply that out by the number of pages allocated.
+ */
+ num_states = (PAGE_SIZE / state_size) * (alloc_size / PAGE_SIZE);
+
+ vm_flags =
+ /*
+ * Don't allow state to be written to swap, to preserve forward secrecy.
+ * But also don't mlock it or pre-reserve it, and allow it to
+ * be discarded under memory pressure. If no memory is available, returns
+ * zeros rather than segfaulting.
+ */
+ VM_DROPPABLE | VM_NORESERVE |
+
+ /* Don't allow the state to survive forks, to prevent random number re-use. */
+ VM_WIPEONFORK |
+
+ /* Don't write random state into coredumps. */
+ VM_DONTDUMP;
+
+ if (mmap_write_lock_killable(current->mm))
+ return -EINTR;
+ pages_addr = do_mmap(NULL, 0, alloc_size, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, vm_flags, 0, &populate, NULL);
+ mmap_write_unlock(current->mm);
+ if (IS_ERR_VALUE(pages_addr))
+ return pages_addr;
+
+ ret = -EFAULT;
+ if (put_user(num_states, num) || put_user(state_size, size_per_each))
+ goto err_unmap;
+
+ return pages_addr;
+
+err_unmap:
+ vm_munmap(pages_addr, alloc_size);
+ return ret;
+}
+#endif
+
/*********************************************************************
*
* Fast key erasure RNG, the "crng".
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 9104952d323d..56368ea4f510 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -906,6 +906,9 @@ asmlinkage long sys_seccomp(unsigned int op, unsigned int flags,
void __user *uargs);
asmlinkage long sys_getrandom(char __user *buf, size_t count,
unsigned int flags);
+asmlinkage long sys_vgetrandom_alloc(unsigned int __user *num,
+ unsigned int __user *size_per_each,
+ unsigned long addr, unsigned int flags);
asmlinkage long sys_memfd_create(const char __user *uname_ptr, unsigned int flags);
asmlinkage long sys_bpf(int cmd, union bpf_attr *attr, unsigned int size);
asmlinkage long sys_execveat(int dfd, const char __user *filename,
diff --git a/include/vdso/getrandom.h b/include/vdso/getrandom.h
new file mode 100644
index 000000000000..69037519d20b
--- /dev/null
+++ b/include/vdso/getrandom.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ */
+
+#ifndef _VDSO_GETRANDOM_H
+#define _VDSO_GETRANDOM_H
+
+/**
+ * struct vgetrandom_state - State used by vDSO getrandom() and allocated by vgetrandom_alloc().
+ *
+ * Currently empty, as the vDSO getrandom() function has not yet been implemented.
+ */
+struct vgetrandom_state { int placeholder; };
+
+#endif /* _VDSO_GETRANDOM_H */
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index d7eee421d4bc..6b17fadb0f59 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -272,6 +272,9 @@ COND_SYSCALL(pkey_free);
/* memfd_secret */
COND_SYSCALL(memfd_secret);
+/* random */
+COND_SYSCALL(vgetrandom_alloc);
+
/*
* Architecture specific weak syscall entries.
*/
diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig
index c46c2300517c..99661b731834 100644
--- a/lib/vdso/Kconfig
+++ b/lib/vdso/Kconfig
@@ -38,3 +38,9 @@ config GENERIC_VDSO_OVERFLOW_PROTECT
in the hotpath.
endif
+
+config VDSO_GETRANDOM
+ bool
+ select NEED_VM_DROPPABLE
+ help
+ Selected by architectures that support vDSO getrandom().
--
2.45.2
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