In the quest to remove all stack VLA usage from the kernel[1], this caps the ahash request size similar to the other limits and adds a sanity check at registration. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@xxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- include/crypto/hash.h | 3 ++- include/crypto/internal/hash.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/include/crypto/hash.h b/include/crypto/hash.h index b9df568dc98e..7d62309baf0b 100644 --- a/include/crypto/hash.h +++ b/include/crypto/hash.h @@ -66,10 +66,11 @@ struct ahash_request { #define AHASH_MAX_DIGESTSIZE (PAGE_SIZE / 8) #define AHASH_MAX_STATESIZE (PAGE_SIZE / 8) +#define AHASH_MAX_REQSIZE (PAGE_SIZE / 8) #define AHASH_REQUEST_ON_STACK(name, ahash) \ char __##name##_desc[sizeof(struct ahash_request) + \ - crypto_ahash_reqsize(ahash)] CRYPTO_MINALIGN_ATTR; \ + AHASH_MAX_REQSIZE] CRYPTO_MINALIGN_ATTR; \ struct ahash_request *name = (void *)__##name##_desc /** diff --git a/include/crypto/internal/hash.h b/include/crypto/internal/hash.h index a0b0ad9d585e..d96ae5f52125 100644 --- a/include/crypto/internal/hash.h +++ b/include/crypto/internal/hash.h @@ -142,6 +142,7 @@ static inline struct ahash_alg *__crypto_ahash_alg(struct crypto_alg *alg) static inline void crypto_ahash_set_reqsize(struct crypto_ahash *tfm, unsigned int reqsize) { + BUG_ON(reqsize > AHASH_MAX_REQSIZE); tfm->reqsize = reqsize; } -- 2.17.1
