Herbert Xu wrote:
> This was detected by the self-test thanks to Ard's chunking patch.
>
> I finally got around to testing this out on my ancient Via box. It
> turns out that the workaround got the assembly wrong and we end up
> doing count + initial cycles of the loop instead of just count.
>
> This obviously causes corruption, either by overwriting the source
> that is yet to be processed, or writing over the end of the buffer.
>
> On CPUs that don't require the workaround only ECB is affected.
> On Nano CPUs both ECB and CBC are affected.
>
> This patch fixes it by doing the subtraction prior to the assembly.
>
> Fixes: a76c1c23d0c3 ("crypto: padlock-aes - work around Nano CPU...")
> Cc: <sta...@vger.kernel.org>
> Reported-by: Jamie Heilman <ja...@audible.transient.net>
> Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
Yay! Tested against 4.14.55 and the self-test passes now on my Esther
system.
> diff --git a/drivers/crypto/padlock-aes.c b/drivers/crypto/padlock-aes.c
> index 1c6cbda..09d823d 100644
> --- a/drivers/crypto/padlock-aes.c
> +++ b/drivers/crypto/padlock-aes.c
> @@ -266,6 +266,8 @@ static inline void padlock_xcrypt_ecb(const u8 *input, u8
> *output, void *key,
> return;
> }
>
> + count -= initial;
> +
> if (initial)
> asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep
> xcryptecb */
> : "+S"(input), "+D"(output)
> @@ -273,7 +275,7 @@ static inline void padlock_xcrypt_ecb(const u8 *input, u8
> *output, void *key,
>
> asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */
> : "+S"(input), "+D"(output)
> - : "d"(control_word), "b"(key), "c"(count - initial));
> + : "d"(control_word), "b"(key), "c"(count));
> }
>
> static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key,
> @@ -284,6 +286,8 @@ static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8
> *output, void *key,
> if (count < cbc_fetch_blocks)
> return cbc_crypt(input, output, key, iv, control_word, count);
>
> + count -= initial;
> +
> if (initial)
> asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep
> xcryptcbc */
> : "+S" (input), "+D" (output), "+a" (iv)
> @@ -291,7 +295,7 @@ static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8
> *output, void *key,
>
> asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" /* rep xcryptcbc */
> : "+S" (input), "+D" (output), "+a" (iv)
> - : "d" (control_word), "b" (key), "c" (count-initial));
> + : "d" (control_word), "b" (key), "c" (count));
> return iv;
> }
>
> --
> Email: Herbert Xu <herb...@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
Jamie Heilman http://audible.transient.net/~jamie/
