On Thu, May 30, 2019 at 6:51 PM Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
>
> From: Eric Biggers <ebiggers@xxxxxxxxxx>
>
> Changing ghash_mod_init() to be subsys_initcall made it start running
> before the alignment fault handler has been installed on ARM. In kernel
> builds where the keys in the ghash test vectors happened to be
> misaligned in the kernel image, this exposed the longstanding bug that
> ghash_setkey() is incorrectly casting the key buffer (which can have any
> alignment) to be128 for passing to gf128mul_init_4k_lle().
>
> Fix this by memcpy()ing the key to a temporary buffer.
>
> Don't fix it by setting an alignmask on the algorithm instead because
> that would unnecessarily force alignment of the data too.
>
> Fixes: 2cdc6899a88e ("crypto: ghash - Add GHASH digest algorithm for GCM")
> Reported-by: Peter Robinson <pbrobinson@xxxxxxxxx>
Tested-by: Peter Robinson <pbrobinson@xxxxxxxxx>
That fixes the problems I was seeing, thanks for the quick response/fix.
Peter
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> ---
> crypto/ghash-generic.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/crypto/ghash-generic.c b/crypto/ghash-generic.c
> index e6307935413c1..c8a347798eae6 100644
> --- a/crypto/ghash-generic.c
> +++ b/crypto/ghash-generic.c
> @@ -34,6 +34,7 @@ static int ghash_setkey(struct crypto_shash *tfm,
> const u8 *key, unsigned int keylen)
> {
> struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
> + be128 k;
>
> if (keylen != GHASH_BLOCK_SIZE) {
> crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
> @@ -42,7 +43,12 @@ static int ghash_setkey(struct crypto_shash *tfm,
>
> if (ctx->gf128)
> gf128mul_free_4k(ctx->gf128);
> - ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
> +
> + BUILD_BUG_ON(sizeof(k) != GHASH_BLOCK_SIZE);
> + memcpy(&k, key, GHASH_BLOCK_SIZE); /* avoid violating alignment rules */
> + ctx->gf128 = gf128mul_init_4k_lle(&k);
> + memzero_explicit(&k, GHASH_BLOCK_SIZE);
> +
> if (!ctx->gf128)
> return -ENOMEM;
>
> --
> 2.22.0.rc1.257.g3120a18244-goog
>
