[openssl/openssl] 6ebf6d: Fix AES OCB encrypt/decrypt for x86 AES-NI

[Richard Levitte]

  Branch: refs/heads/master
  Home:   https://github.openssl.org/openssl/openssl
  Commit: 6ebf6d51596f51d23ccbc17930778d104a57d99c
      https://github.openssl.org/openssl/openssl/commit/6ebf6d51596f51d23ccbc17930778d104a57d99c
  Author: Alex Chernyakhovsky <achernya at google.com>
  Date:   2022-07-05 (Tue, 05 Jul 2022)

  Changed paths:
    M crypto/aes/asm/aesni-x86.pl

  Log Message:
  -----------
  Fix AES OCB encrypt/decrypt for x86 AES-NI

aesni_ocb_encrypt and aesni_ocb_decrypt operate by having a fast-path
that performs operations on 6 16-byte blocks concurrently (the
"grandloop") and then proceeds to handle the "short" tail (which can
be anywhere from 0 to 5 blocks) that remain.

As part of initialization, the assembly initializes $len to the true
length, less 96 bytes and converts it to a pointer so that the $inp
can be compared to it. Each iteration of "grandloop" checks to see if
there's a full 96-byte chunk to process, and if so, continues. Once
this has been exhausted, it falls through to "short", which handles
the remaining zero to five blocks.

Unfortunately, the jump at the end of "grandloop" had a fencepost
error, doing a `jb` ("jump below") rather than `jbe` (jump below or
equal). This should be `jbe`, as $inp is pointing to the *end* of the
chunk currently being handled. If $inp == $len, that means that
there's a whole 96-byte chunk waiting to be handled. If $inp > $len,
then there's 5 or fewer 16-byte blocks left to be handled, and the
fall-through is intended.

The net effect of `jb` instead of `jbe` is that the last 16-byte block
of the last 96-byte chunk was completely omitted. The contents of
`out` in this position were never written to. Additionally, since
those bytes were never processed, the authentication tag generated is
also incorrect.

The same fencepost error, and identical logic, exists in both
aesni_ocb_encrypt and aesni_ocb_decrypt.

This addresses CVE-2022-2097.

Co-authored-by: Alejandro Sedeño <asedeno at google.com>
Co-authored-by: David Benjamin <davidben at google.com>

Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>


  Commit: 2f19ab18a29cf9c82cdd68bc8c7e5be5061b19be
      https://github.openssl.org/openssl/openssl/commit/2f19ab18a29cf9c82cdd68bc8c7e5be5061b19be
  Author: Alex Chernyakhovsky <achernya at google.com>
  Date:   2022-07-05 (Tue, 05 Jul 2022)

  Changed paths:
    M test/recipes/30-test_evp_data/evpciph_aes_ocb.txt

  Log Message:
  -----------
  AES OCB test vectors

Add test vectors for AES OCB for x86 AES-NI multiple of 96 byte issue.

Co-authored-by: Alejandro Sedeño <asedeno at google.com>
Co-authored-by: David Benjamin <davidben at google.com>

Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>


Compare: https://github.openssl.org/openssl/openssl/compare/7fe7cc57af3d...2f19ab18a29c