On Mon, Jul 16, 2018 at 09:21:40PM -0700, Kees Cook wrote: > In the quest to remove all stack VLA usage from the kernel[1], this uses > the maximum blocksize and adds a sanity check. For xcbc, the blocksize > must always be 16, so use that, since it's already being enforced during > instantiation. > > [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@xxxxxxxxxxxxxx > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > crypto/xcbc.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/crypto/xcbc.c b/crypto/xcbc.c > index 25c75af50d3f..7aa03beed795 100644 > --- a/crypto/xcbc.c > +++ b/crypto/xcbc.c > @@ -57,6 +57,8 @@ struct xcbc_desc_ctx { > u8 ctx[]; > }; > > +#define XCBC_BLOCKSIZE 16 > + > static int crypto_xcbc_digest_setkey(struct crypto_shash *parent, > const u8 *inkey, unsigned int keylen) > { > @@ -65,7 +67,10 @@ static int crypto_xcbc_digest_setkey(struct crypto_shash *parent, > int bs = crypto_shash_blocksize(parent); > u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); > int err = 0; > - u8 key1[bs]; > + u8 key1[XCBC_BLOCKSIZE]; > + > + if (WARN_ON(bs > sizeof(key1))) > + return -EINVAL; Please remove this. You already checked it in xcbc_create. In fact, you should just make bs XCBC_BLOCKSIZE unconditinoally in this function. Cheers, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
