[PATCH] crypto: vmx - CTR: always increment IV as quadword

[Herbert Xu]

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: stable at vger.kernel.org
> Signed-off-by: Daniel Axtens <dja at axtens.net>
> 
> ---
> 
> 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 <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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