On Tue, Nov 28, 2023 at 01:38:29PM +0800, Jerry Shih wrote: > On Nov 28, 2023, at 11:58, Eric Biggers <ebiggers@xxxxxxxxxx> wrote: > > On Mon, Nov 27, 2023 at 03:06:55PM +0800, Jerry Shih wrote: > >> The `walksize` assignment is missed in simd skcipher. > >> > >> Signed-off-by: Jerry Shih <jerry.shih@xxxxxxxxxx> > >> --- > >> crypto/cryptd.c | 1 + > >> crypto/simd.c | 1 + > >> 2 files changed, 2 insertions(+) > >> > >> diff --git a/crypto/cryptd.c b/crypto/cryptd.c > >> index bbcc368b6a55..253d13504ccb 100644 > >> --- a/crypto/cryptd.c > >> +++ b/crypto/cryptd.c > >> @@ -405,6 +405,7 @@ static int cryptd_create_skcipher(struct crypto_template *tmpl, > >> (alg->base.cra_flags & CRYPTO_ALG_INTERNAL); > >> inst->alg.ivsize = crypto_skcipher_alg_ivsize(alg); > >> inst->alg.chunksize = crypto_skcipher_alg_chunksize(alg); > >> + inst->alg.walksize = crypto_skcipher_alg_walksize(alg); > >> inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg); > >> inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg); > >> > >> diff --git a/crypto/simd.c b/crypto/simd.c > >> index edaa479a1ec5..ea0caabf90f1 100644 > >> --- a/crypto/simd.c > >> +++ b/crypto/simd.c > >> @@ -181,6 +181,7 @@ struct simd_skcipher_alg *simd_skcipher_create_compat(const char *algname, > >> > >> alg->ivsize = ialg->ivsize; > >> alg->chunksize = ialg->chunksize; > >> + alg->walksize = ialg->walksize; > >> alg->min_keysize = ialg->min_keysize; > >> alg->max_keysize = ialg->max_keysize; > > > > What are the consequences of this bug? I wonder if it actually matters? The > > "inner" algorithm is the one that actually gets used for the "walk", right? > > > > - Eric > > Without this, we might still use chunksize or cra_blocksize as the walksize > even though we setup with the larger walksize. > > Here is the code for the walksize default value: > static int skcipher_prepare_alg(struct skcipher_alg *alg) > { > ... > if (!alg->chunksize) > alg->chunksize = base->cra_blocksize; > if (!alg->walksize) > alg->walksize = alg->chunksize; > > And we already have the bigger walksize for x86 aes-xts. > .base = { > .cra_name = "__xts(aes)", > ... > }, > .walksize = 2 * AES_BLOCK_SIZE, > > The x86 aes-xts only uses one `walk` to handle the tail elements. It assumes > that the walksize contains 2 aes blocks. If walksize is not set correctly, maybe > some tail elements is not processed in simd-cipher mode for x86 aes-xts. With the SIMD helper there are three "algorithms": the underlying algorithm, the cryptd algorithm, and the simd algorithm. This patch makes the "walksize" property be propagated from the underlying algorithm to the cryptd and simd algorithms. I don't see how that actually makes a difference, since the only place the skcipher_walk happens is on the underlying algorithm. So it uses the "walksize" from the underlying algorithm, right? - Eric