[PATCH v5 0/9] Inline Encryption Support

Satya Tangirala
2019-10-28T07:20:40Z

This patch series adds support for Inline Encryption to the block layer,
UFS, fscrypt, f2fs and ext4.

This patchset applies to fscrypt.git#master with the additional patchset
"[PATCH 0/3] fscrypt: support for inline-encryption-optimized policies"
applied. It can be retrieved from git at
https://git.kernel.org/pub/scm/fs/fscrypt/fscrypt.git/log/?h=inline-encryption-v5
Note however, that the patches for the block layer (i.e. patches 1, 2 and 3)
can be applied independently.

Inline Encryption hardware allows software to specify an encryption context
(an encryption key, crypto algorithm, data unit num, data unit size, etc.)
along with a data transfer request to a storage device, and the inline
encryption hardware will use that context to en/decrypt the data. The
inline encryption hardware is part of the storage device, and it
conceptually sits on the data path between system memory and the storage
device. Inline Encryption hardware has become increasingly common, and we
want to support it in the kernel.

Inline Encryption hardware implementations often function around the
concept of a limited number of "keyslots", which can hold an encryption
context each. The storage device can be directed to en/decrypt any
particular request with the encryption context stored in any particular
keyslot.

Patch 1 introduces a Keyslot Manager to efficiently manage keyslots.
The keyslot manager also functions as the interface that blk-crypto
(introduced in Patch 3), will use to program keys into inline encryption
hardware. For more information on the Keyslot Manager, refer to
documentation found in block/keyslot-manager.c and linux/keyslot-manager.h.

Patch 2 introduces struct bio_crypt_ctx, and a ptr to one in struct bio,
which allows struct bio to represent an encryption context that can be
passed down the storage stack from the filesystem layer to the storage
driver.

Patch 3 introduces blk-crypto. Blk-crypto delegates crypto operations to
inline encryption hardware when available, and also contains a software
fallback to the kernel crypto API. Blk-crypto also makes it possible for
layered devices like device mapper to make use of inline encryption
hardware. Given that blk-crypto works as a software fallback, we are
considering removing file content en/decryption from fscrypt and simply
using blk-crypto in a future patch. For more details on blk-crypto, refer
to Documentation/block/inline-encryption.rst.

Patches 4-6 add support for inline encryption into the UFS driver according
to the JEDEC UFS HCI v2.1 specification. Inline encryption support for
other drivers (like eMMC) may be added in the same way - the device driver
should set up a Keyslot Manager in the device's request_queue (refer to
the UFS crypto additions in ufshcd-crypto.c and ufshcd.c for an example).

Patch 7 adds support to fscrypt - to use inline encryption with fscrypt,
the filesystem must be mounted with '-o inlinecrypt' - when this option is
specified, the contents of any AES-256-XTS encrypted file will be
encrypted using blk-crypto.

Patches 8 and 9 add support to f2fs and ext4 respectively, so that we have
a complete stack that can make use of inline encryption.

The patches were tested running kvm-xfstests, by specifying the introduced
"inlinecrypt" mount option, so that encryption happens in blk-crypto.

There have been a few patch sets addressing Inline Encryption Support in
the past. Briefly, this patch set differs from those as follows:

1) "crypto: qce: ice: Add support for Inline Crypto Engine"
is specific to certain hardware, while our patch set's Inline
Encryption support for UFS is implemented according to the JEDEC UFS
specification.

2) "scsi: ufs: UFS Host Controller crypto changes" registers inline
encryption support as a kernel crypto algorithm. Our patch views inline
encryption as being fundamentally different from a generic crypto
provider (in that inline encryption is tied to a device), and so does
not use the kernel crypto API to represent inline encryption hardware.

3) "scsi: ufs: add real time/inline crypto support to UFS HCD" requires
the device mapper to work - our patch does not.

Changes v4 => v5:
- The fscrypt patch has been separated into 2. The first adds support
for the IV_INO_LBLK_64 policy (which was called INLINE_CRYPT_OPTIMIZED
in past versions of this series). This policy is now purely an on disk
format, and doesn't dictate whether blk-crypto is used for file content
encryption or not. Instead, this is now decided based on the
"inlinecrypt" mount option.
- Inline crypto key eviction is now handled by blk-crypto instead of
fscrypt.
- More refactoring.

Changes v3 => v4:
- Fixed the issue with allocating crypto_skcipher in
blk_crypto_keyslot_program.
- bio_crypto_alloc_ctx is now mempool backed.
- In f2fs, a bio's bi_crypt_context is now set up when the
bio is allocated, rather than just before the bio is
submitted - this fixes bugs in certain cases, like when an
encrypted block is being moved without decryption.
- Lots of refactoring and cleanup of blk-crypto - thanks Eric!

Changes v2 => v3:
- Overhauled keyslot manager's get keyslot logic and optimized LRU.
- Block crypto en/decryption fallback now supports data unit sizes
that divide the bvec length (instead of requiring each bvec's length
to be the same as the data unit size).
- fscrypt master key is now keyed additionally by super_block and
ci_ctfm != NULL.
- all references of "hw encryption" are replaced by inline encryption.
- address various other review comments from Eric.

Changes v1 => v2:
- Block layer and UFS changes are split into 3 patches each.
- We now only have a ptr to a struct bio_crypt_ctx in struct bio, instead
of the struct itself.
- struct bio_crypt_ctx no longer has flags.
- blk-crypto now correctly handles the case when it fails to init
(because of insufficient memory), but kernel continues to boot.
- ufshcd-crypto now works on big endian cpus.
- Many cleanups.

Eric Biggers (1):
ext4: add inline encryption support

Satya Tangirala (8):
block: Keyslot Manager for Inline Encryption
block: Add encryption context to struct bio
block: blk-crypto for Inline Encryption
scsi: ufs: UFS driver v2.1 spec crypto additions
scsi: ufs: UFS crypto API
scsi: ufs: Add inline encryption support to UFS
fscrypt: add inline encryption support
f2fs: add inline encryption support

Documentation/block/index.rst | 1 +
Documentation/block/inline-encryption.rst | 183 +++++
block/Kconfig | 10 +
block/Makefile | 2 +
block/bio-crypt-ctx.c | 142 ++++
block/bio.c | 23 +-
block/blk-core.c | 14 +-
block/blk-crypto.c | 798 ++++++++++++++++++++++
block/blk-merge.c | 35 +-
block/bounce.c | 15 +-
block/keyslot-manager.c | 352 ++++++++++
drivers/md/dm.c | 15 +-
drivers/scsi/ufs/Kconfig | 9 +
drivers/scsi/ufs/Makefile | 1 +
drivers/scsi/ufs/ufshcd-crypto.c | 391 +++++++++++
drivers/scsi/ufs/ufshcd-crypto.h | 86 +++
drivers/scsi/ufs/ufshcd.c | 85 ++-
drivers/scsi/ufs/ufshcd.h | 25 +
drivers/scsi/ufs/ufshci.h | 67 +-
fs/buffer.c | 3 +
fs/crypto/Kconfig | 6 +
fs/crypto/Makefile | 1 +
fs/crypto/bio.c | 31 +-
fs/crypto/fscrypt_private.h | 72 ++
fs/crypto/inline_crypt.c | 390 +++++++++++
fs/crypto/keyring.c | 2 +
fs/crypto/keysetup.c | 18 +-
fs/ext4/ext4.h | 1 +
fs/ext4/inode.c | 4 +-
fs/ext4/page-io.c | 11 +-
fs/ext4/readpage.c | 15 +-
fs/ext4/super.c | 13 +
fs/f2fs/data.c | 76 ++-
fs/f2fs/f2fs.h | 3 +
fs/f2fs/super.c | 20 +
include/linux/bio-crypt-ctx.h | 226 ++++++
include/linux/bio.h | 1 +
include/linux/blk-crypto.h | 62 ++
include/linux/blk_types.h | 6 +
include/linux/blkdev.h | 6 +
include/linux/fscrypt.h | 60 ++
include/linux/keyslot-manager.h | 98 +++
42 files changed, 3318 insertions(+), 61 deletions(-)
create mode 100644 Documentation/block/inline-encryption.rst
create mode 100644 block/bio-crypt-ctx.c
create mode 100644 block/blk-crypto.c
create mode 100644 block/keyslot-manager.c
create mode 100644 drivers/scsi/ufs/ufshcd-crypto.c
create mode 100644 drivers/scsi/ufs/ufshcd-crypto.h
create mode 100644 fs/crypto/inline_crypt.c
create mode 100644 include/linux/bio-crypt-ctx.h
create mode 100644 include/linux/blk-crypto.h
create mode 100644 include/linux/keyslot-manager.h

--
2.24.0.rc0.303.g954a862665-goog