[PATCH v2 08/11] crypto: qat: Remove VLA usage

Kees Cook
2018-06-25T21:10:52Z

In the quest to remove all stack VLA usage from the kernel[1], this uses
the new upper bound for the stack buffer. Also adds a sanity check.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Cc: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: qat-linux@intel.com
Cc: linux-crypto@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/crypto/qat/qat_common/qat_algs.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/qat/qat_common/qat_algs.c b/drivers/crypto/qat/qat_common/qat_algs.c
index 1138e41d6805..a28edf7b792f 100644
--- a/drivers/crypto/qat/qat_common/qat_algs.c
+++ b/drivers/crypto/qat/qat_common/qat_algs.c
@@ -153,8 +153,8 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
struct sha512_state sha512;
int block_size = crypto_shash_blocksize(ctx->hash_tfm);
int digest_size = crypto_shash_digestsize(ctx->hash_tfm);
- char ipad[block_size];
- char opad[block_size];
+ char ipad[MAX_ALGAPI_BLOCKSIZE];
+ char opad[MAX_ALGAPI_BLOCKSIZE];
__be32 *hash_state_out;
__be64 *hash512_state_out;
int i, offset;
@@ -164,6 +164,10 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
shash->tfm = ctx->hash_tfm;
shash->flags = 0x0;

+ if (WARN_ON(block_size > sizeof(ipad) ||
+ sizeof(ipad) != sizeof(opad)))
+ return -EINVAL;
+
if (auth_keylen > block_size) {
int ret = crypto_shash_digest(shash, auth_key,
auth_keylen, ipad);
--
2.17.1