[dm-devel] [PATCH v13 0/6] crypto: switch to crypto API for ESSIV generation
Herbert Xu
herbert at gondor.apana.org.au
Fri Aug 30 08:18:52 UTC 2019
On Mon, Aug 19, 2019 at 05:17:32PM +0300, Ard Biesheuvel wrote:
> This series creates an ESSIV template that produces a skcipher or AEAD
> transform based on a tuple of the form '<skcipher>,<shash>' (or '<aead>,<shash>'
> for the AEAD case). It exposes the encapsulated sync or async skcipher/aead by
> passing through all operations, while using the cipher/shash pair to transform
> the input IV into an ESSIV output IV.
>
> Changes since v12:
> - don't use a per-instance shash but only record the cra_driver_name of the
> shash when instantiating the template, and allocate the shash for each
> allocated transform instead
> - add back the dm-crypt patch -> as Milan has indicated, his preference would
> be to queue these changes for v5.4 (with the first patch shared between the
> cryptodev and md trees on a stable branch based on v5.3-rc1 - if needed,
> I can provide a signed tag)
>
> Changes since v11:
> - Avoid spawns for the ESSIV shash and cipher algos. Instead, the shash TFM is
> allocated per-instance (which is appropriate since it is unkeyed and thus
> stateless), and the cipher is allocated explicitly based on the parsed
> skcipher/aead cra_name.
>
> Changes since v10:
> - Drop patches against fscrypt and dm-crypt - these will be routed via the
> respective maintainer trees during the next cycle
> - Fix error handling when parsing the cipher name from the skcipher cra_name
> - Use existing ivsize temporary instead of retrieving it again
> - Expose cra_name via module alias (#4)
>
> Changes since v9:
> - Fix cipher_api parsing bug that was introduced by dropping the cipher name
> parsing patch in v9 (#3). Thanks to Milan for finding it.
> - Fix a couple of instances where the old essiv(x,y,z) format was used in
> comments instead of the essiv(x,z) format we adopted in v9
>
> Changes since v8:
> - Remove 'cipher' argument from essiv() template, and instead, parse the
> cra_name of the skcipher to obtain the cipher. This is slightly cleaner
> than what dm-crypt currently does, since we can get the cra_name from the
> spawn, and we don't have to actually allocate the TFM. Since this implies
> that dm-crypt does not need to provide the cipher, we can drop the parsing
> code from it entirely (assuming the eboiv patch I sent out recently is
> applied first) (patch #7)
> - Restrict the essiv() AEAD instantiation to AEADs whose cra_name starts with
> 'authenc('
> - Rebase onto cryptodev/master
> - Drop dm-crypt to reorder/refactor cipher name parsing, since it was wrong
> and it is no longer needed.
> - Drop Milan's R-b since the code has changed
> - Fix bug in accelerated arm64 implementation.
>
> Changes since v7:
> - rebase onto cryptodev/master
> - drop change to ivsize in #2
> - add Milan's R-b's
>
> Changes since v6:
> - make CRYPTO_ESSIV user selectable so we can opt out of selecting it even
> if FS_ENCRYPTION (which cannot be built as a module) is enabled
> - move a comment along with the code it referred to (#3), not that this change
> and removing some redundant braces makes the diff look totally different
> - add Milan's R-b to #3 and #4
>
> Changes since v5:
> - drop redundant #includes and drop some unneeded braces (#2)
> - add test case for essiv(authenc(hmac(sha256),cbc(aes)),aes,sha256)
> - make ESSIV driver deal with assoc data that is described by more than two
> scatterlist entries - this only happens when the extended tests are being
> performed, so don't optimize for it
> - clarify that both fscrypt and dm-crypt only use ESSIV in special cases (#7)
>
> Changes since v4:
> - make the ESSIV template IV size equal the IV size of the encapsulated
> cipher - defining it as 8 bytes was needlessly restrictive, and also
> complicated the code for no reason
> - add a missing kfree() spotted by Smatch
> - add additional algo length name checks when constructing the essiv()
> cipher name
> - reinstate the 'essiv' IV generation implementation in dm-crypt, but
> make its generation function identical to plain64le (and drop the other
> methods)
> - fix a bug in the arm64 CE/NEON code
> - simplify the arm64 code by reusing more of the existing CBC implementation
> (patch #6 is new to this series and was added for this reason)
>
> Changes since v3:
> - address various review comments from Eric on patch #1
> - use Kconfig's 'imply' instead of 'select' to permit CRYPTO_ESSIV to be
> enabled as a module or disabled entirely even if fscrypt is compiled in (#2)
> - fix an issue in the AEAD encrypt path caused by the IV being clobbered by
> the inner skcipher before the hmac was being calculated
>
> Changes since v2:
> - fixed a couple of bugs that snuck in after I'd done the bulk of my
> testing
> - some cosmetic tweaks to the ESSIV template skcipher setkey function
> to align it with the aead one
> - add a test case for essiv(cbc(aes),aes,sha256)
> - add an accelerated implementation for arm64 that combines the IV
> derivation and the actual en/decryption in a single asm routine
>
> Code can be found here
> https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/log/?h=essiv-v11
>
> Cc: Herbert Xu <herbert at gondor.apana.org.au>
> Cc: Eric Biggers <ebiggers at google.com>
> Cc: dm-devel at redhat.com
> Cc: linux-fscrypt at vger.kernel.org
> Cc: Gilad Ben-Yossef <gilad at benyossef.com>
> Cc: Milan Broz <gmazyland at gmail.com>
>
> Ard Biesheuvel (6):
> crypto: essiv - create wrapper template for ESSIV generation
> crypto: essiv - add tests for essiv in cbc(aes)+sha256 mode
> crypto: arm64/aes-cts-cbc - factor out CBC en/decryption of a walk
> crypto: arm64/aes - implement accelerated ESSIV/CBC mode
> md: dm-crypt: switch to ESSIV crypto API template
> md: dm-crypt: omit parsing of the encapsulated cipher
>
> arch/arm64/crypto/aes-glue.c | 206 ++++--
> arch/arm64/crypto/aes-modes.S | 28 +
> crypto/Kconfig | 28 +
> crypto/Makefile | 1 +
> crypto/essiv.c | 663 ++++++++++++++++++++
> crypto/tcrypt.c | 9 +
> crypto/testmgr.c | 14 +
> crypto/testmgr.h | 497 +++++++++++++++
> drivers/md/Kconfig | 1 +
> drivers/md/dm-crypt.c | 271 ++------
> 10 files changed, 1448 insertions(+), 270 deletions(-)
> create mode 100644 crypto/essiv.c
Patches 2-4 applied. Thanks.
--
Email: Herbert Xu <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
More information about the dm-devel
mailing list