From b68a7ec1e9a3efac53ae26a1658a553825a2375c Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 7 Aug 2018 14:18:38 -0700 Subject: crypto: hash - Remove VLA usage In the quest to remove all stack VLA usage from the kernel[1], this removes the VLAs in SHASH_DESC_ON_STACK (via crypto_shash_descsize()) by using the maximum allowable size (which is now more clearly captured in a macro), along with a few other cases. Similar limits are turned into macros as well. A review of existing sizes shows that SHA512_DIGEST_SIZE (64) is the largest digest size and that sizeof(struct sha3_state) (360) is the largest descriptor size. The corresponding maximums are reduced. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook Signed-off-by: Herbert Xu --- include/crypto/hash.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/crypto/hash.h b/include/crypto/hash.h index 76e432cab75d..21587011ab0f 100644 --- a/include/crypto/hash.h +++ b/include/crypto/hash.h @@ -151,9 +151,13 @@ struct shash_desc { void *__ctx[] CRYPTO_MINALIGN_ATTR; }; +#define HASH_MAX_DIGESTSIZE 64 +#define HASH_MAX_DESCSIZE 360 +#define HASH_MAX_STATESIZE 512 + #define SHASH_DESC_ON_STACK(shash, ctx) \ char __##shash##_desc[sizeof(struct shash_desc) + \ - crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \ + HASH_MAX_DESCSIZE] CRYPTO_MINALIGN_ATTR; \ struct shash_desc *shash = (struct shash_desc *)__##shash##_desc /** -- cgit