On 06/20/2018 07:04 PM, Kees Cook wrote:
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>
I get:
crypto/algif_hash.c: In function ‘hash_accept’:
crypto/algif_hash.c:276:1: warning: the frame size of 2048 bytes is
larger than 1024 bytes [-Wframe-larger-than=]
Christophe
---
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; \
--
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