On Wed, May 15, 2019 at 08:24:50PM +1000, Daniel Axtens wrote:
> The kernel self-tests picked up an issue with CTR mode:
> alg: skcipher: p8_aes_ctr encryption test failed (wrong result) on test
> vector 3, cfg="uneven misaligned splits, may sleep"
>
> Test vector 3 has an IV of FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFD, so
> after 3 increments it should wrap around to 0.
>
> In the aesp8-ppc code from OpenSSL, there are two paths that
> increment IVs: the bulk (8 at a time) path, and the individual
> path which is used when there are fewer than 8 AES blocks to
> process.
>
> In the bulk path, the IV is incremented with vadduqm: "Vector
> Add Unsigned Quadword Modulo", which does 128-bit addition.
>
> In the individual path, however, the IV is incremented with
> vadduwm: "Vector Add Unsigned Word Modulo", which instead
> does 4 32-bit additions. Thus the IV would instead become
> FFFFFFFFFFFFFFFFFFFFFFFF00000000, throwing off the result.
>
> Use vadduqm.
>
> This was probably a typo originally, what with q and w being
> adjacent. It is a pretty narrow edge case: I am really
> impressed by the quality of the kernel self-tests!
>
> Fixes: 5c380d623ed3 ("crypto: vmx - Add support for VMS instructions by ASM")
> Cc: [email protected]
> Signed-off-by: Daniel Axtens <[email protected]>
>
> ---
>
> I'll pass this along internally to get it into OpenSSL as well.
> ---
> drivers/crypto/vmx/aesp8-ppc.pl | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
