In the quest to remove all stack VLA usage from the kernel[1], this introduces max size macros for ahash, as already done for shash, and adjust the crypto user to max state size. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@xxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- crypto/ahash.c | 4 ++-- crypto/algif_hash.c | 2 +- include/crypto/hash.h | 3 +++ 3 files changed, 6 insertions(+), 3 deletions(-) diff --git a/crypto/ahash.c b/crypto/ahash.c index a64c143165b1..6435bdbe42fd 100644 --- a/crypto/ahash.c +++ b/crypto/ahash.c @@ -550,8 +550,8 @@ static int ahash_prepare_alg(struct ahash_alg *alg) { struct crypto_alg *base = &alg->halg.base; - if (alg->halg.digestsize > PAGE_SIZE / 8 || - alg->halg.statesize > PAGE_SIZE / 8 || + if (alg->halg.digestsize > AHASH_MAX_DIGESTSIZE || + alg->halg.statesize > AHASH_MAX_STATESIZE || alg->halg.statesize == 0) return -EINVAL; diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index bfcf595fd8f9..8974ee8ebead 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -239,7 +239,7 @@ static int hash_accept(struct socket *sock, struct socket *newsock, int flags, struct alg_sock *ask = alg_sk(sk); struct hash_ctx *ctx = ask->private; struct ahash_request *req = &ctx->req; - char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req)) ? : 1]; + char state[AHASH_MAX_STATESIZE]; struct sock *sk2; struct alg_sock *ask2; struct hash_ctx *ctx2; diff --git a/include/crypto/hash.h b/include/crypto/hash.h index 308aad8bf523..b9df568dc98e 100644 --- a/include/crypto/hash.h +++ b/include/crypto/hash.h @@ -64,6 +64,9 @@ struct ahash_request { void *__ctx[] CRYPTO_MINALIGN_ATTR; }; +#define AHASH_MAX_DIGESTSIZE (PAGE_SIZE / 8) +#define AHASH_MAX_STATESIZE (PAGE_SIZE / 8) + #define AHASH_REQUEST_ON_STACK(name, ahash) \ char __##name##_desc[sizeof(struct ahash_request) + \ crypto_ahash_reqsize(ahash)] CRYPTO_MINALIGN_ATTR; \ -- 2.17.1
