diff options
| author | Kees Cook <keescook@chromium.org> | 2018-08-08 00:18:38 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2018-09-04 06:35:03 +0300 |
| commit | b68a7ec1e9a3efac53ae26a1658a553825a2375c (patch) | |
| tree | 6ad87c86f0fc4aeafee091c6d43043876f081d0b | |
| parent | ebf533adc877d9171800bbce77372d8051fc35c2 (diff) | |
| download | linux-b68a7ec1e9a3efac53ae26a1658a553825a2375c.tar.xz | |
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 <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
| -rw-r--r-- | crypto/ahash.c | 4 | ||||
| -rw-r--r-- | crypto/algif_hash.c | 2 | ||||
| -rw-r--r-- | crypto/shash.c | 6 | ||||
| -rw-r--r-- | include/crypto/hash.h | 6 |
4 files changed, 11 insertions, 7 deletions
diff --git a/crypto/ahash.c b/crypto/ahash.c index a64c143165b1..78aaf2158c43 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 > HASH_MAX_DIGESTSIZE || + alg->halg.statesize > HASH_MAX_STATESIZE || alg->halg.statesize == 0) return -EINVAL; diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index bfcf595fd8f9..d0cde541beb6 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[HASH_MAX_STATESIZE]; struct sock *sk2; struct alg_sock *ask2; struct hash_ctx *ctx2; diff --git a/crypto/shash.c b/crypto/shash.c index 5d732c6bb4b2..86d76b5c626c 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -458,9 +458,9 @@ static int shash_prepare_alg(struct shash_alg *alg) { struct crypto_alg *base = &alg->base; - if (alg->digestsize > PAGE_SIZE / 8 || - alg->descsize > PAGE_SIZE / 8 || - alg->statesize > PAGE_SIZE / 8) + if (alg->digestsize > HASH_MAX_DIGESTSIZE || + alg->descsize > HASH_MAX_DESCSIZE || + alg->statesize > HASH_MAX_STATESIZE) return -EINVAL; base->cra_type = &crypto_shash_type; 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 /** |