On Tue, Aug 07, 2018 at 02:18:43PM -0700, Kees Cook wrote: > In the quest to remove all stack VLA usage from the kernel[1], this > caps the skcipher request size similar to other limits and adds a sanity > check at registration. Looking at instrumented tcrypt output, the largest > is for lrw: > > crypt: testing lrw(aes) > crypto_skcipher_set_reqsize: 8 > crypto_skcipher_set_reqsize: 88 > crypto_skcipher_set_reqsize: 472 > > [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@xxxxxxxxxxxxxx > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > include/crypto/internal/skcipher.h | 1 + > include/crypto/skcipher.h | 4 +++- > 2 files changed, 4 insertions(+), 1 deletion(-) > > diff --git a/include/crypto/internal/skcipher.h b/include/crypto/internal/skcipher.h > index e42f7063f245..5035482cbe68 100644 > --- a/include/crypto/internal/skcipher.h > +++ b/include/crypto/internal/skcipher.h > @@ -130,6 +130,7 @@ static inline struct crypto_skcipher *crypto_spawn_skcipher( > static inline void crypto_skcipher_set_reqsize( > struct crypto_skcipher *skcipher, unsigned int reqsize) > { > + BUG_ON(reqsize > SKCIPHER_MAX_REQSIZE); Please do not add these BUG_ONs. Instead allow this function to fail and check for the failure in the caller. Thanks, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
