[PATCH v2 0/9] crypto: Provide a function for zeroizing crypto_aes_ctx

[Thomas Huth <thuth@redhat.com>]

Several crypto drivers need to zeroize their local crypto_aes_ctx
structures after use to avoid leaking key material on the stack.
Currently some call sites do this with their own memzero_explicit()
call, which is error-prone since it is easy to miss a return path
(what already happened in some drivers). Some other call sites miss
to clear crypto_aes_ctx completely.

To improve this situation, the first patch introduces an aes_clear_ctx()
helper that can be used with __cleanup() to automatically zeroize the
context when it goes out of scope. The following 6 patches add this
__cleanup() to spots in the code where this has been forgotten so far.
The final two patches change some files to do the zeroization with
the new __cleanup() way instead of calling memzero_explicit() manually.

v2:
- I sent out v1 last week, but I think it never reached the mailing list.
  Either a PEBKAC or a mail server problem... 🤷‍♂️ 
- Rebased onto cryptodev master branch, updated the "qat" patch accordingly

Thomas Huth (9):
  crypto: Provide a wrapper for zeroizing crypto_aes_ctx
  crypto: aspeed - clear the crypto_aes_ctx when done
  crypto: inside-secure/eip93 - clear the crypto_aes_ctx when done
  crypto: padlock-aes - clear the crypto_aes_ctx when done
  crypto: sa2ul - clear the crypto_aes_ctx when done
  crypto: arm/aes-neonbs - clear the crypto_aes_ctx when done
  crypto: arm64/aes-neonbs - clear the crypto_aes_ctx when done
  crypto: safexcel - zeroize crypto_aes_ctx with
    __cleanup(aes_clear_ctx)
  crypto: qat - zeroize crypto_aes_ctx with __cleanup(aes_clear_ctx)

 arch/arm/crypto/aes-neonbs-glue.c                 |  2 +-
 arch/arm64/crypto/aes-neonbs-glue.c               |  2 +-
 drivers/crypto/aspeed/aspeed-hace-crypto.c        |  3 +--
 drivers/crypto/inside-secure/eip93/eip93-aead.c   |  2 +-
 drivers/crypto/inside-secure/eip93/eip93-cipher.c |  2 +-
 drivers/crypto/inside-secure/safexcel_cipher.c    | 15 +++++----------
 drivers/crypto/inside-secure/safexcel_hash.c      |  3 +--
 drivers/crypto/intel/qat/qat_common/qat_algs.c    |  3 +--
 drivers/crypto/padlock-aes.c                      |  2 +-
 drivers/crypto/sa2ul.c                            |  2 +-
 include/crypto/aes.h                              | 13 +++++++++++++
 11 files changed, 27 insertions(+), 22 deletions(-)

-- 
2.55.0