On Mon, Oct 10, 2016 at 10:29:55AM -0700, Joe Perches wrote: > On Mon, 2016-10-10 at 10:15 -0700, Eric Biggers wrote: > > The per-transform 'consts' array is accessed as __be64 in > > crypto_cmac_digest_setkey() but was only guaranteed to be aligned to > > __alignof__(long). Fix this by aligning it to __alignof__(__be64). > [] > > diff --git a/crypto/cmac.c b/crypto/cmac.c > [] > > @@ -57,7 +57,8 @@ static int crypto_cmac_digest_setkey(struct crypto_shash > > *parent, > > unsigned long alignmask = crypto_shash_alignmask(parent); > > struct cmac_tfm_ctx *ctx = crypto_shash_ctx(parent); > > unsigned int bs = crypto_shash_blocksize(parent); > > - __be64 *consts = PTR_ALIGN((void *)ctx->ctx, alignmask + 1); > > + __be64 *consts = PTR_ALIGN((void *)ctx->ctx, > > + (alignmask | (__alignof__(__be64) - 1)) + 1); > > Using a bitwise or looks very odd there. Perhaps: > > min(alignmask + 1, __alignof__(__be64)) >
Alignment has to be a power of 2. From the code I've read, crypto drivers work with alignment a lot and use bitwise OR to mean "the more restrictive of these alignmasks". So I believe the way it's written is the preferred style. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
