Arnd reports that with Kees's latest VLA patches applied, the HMAC
handling in the QAT driver uses a worst case estimate of 160 bytes
for the SHA blocksize, allowing the compiler to determine the size
of the stack frame at runtime and throw a warning:
drivers/crypto/qat/qat_common/qat_algs.c: In function 'qat_alg_do_precomputes':
drivers/crypto/qat/qat_common/qat_algs.c:257:1: error: the frame size
of 1112 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
Given that this worst case estimate is only 32 bytes larger than the
actual block size of SHA-512, the use of a VLA here was hiding the
excessive size of the stack frame from the compiler, and so we should
try to move these buffers off the stack.
So move the ipad/opad buffers and the various SHA state descriptors
into the tfm context struct. Since qat_alg_do_precomputes() is only
called in the context of a setkey() operation, this should be safe.
Using SHA512_BLOCK_SIZE for the size of the ipad/opad buffers allows
them to be used by SHA-1/SHA-256 as well.
Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
This applies against v4.19-rc while Arnd's report was about -next. However,
since Kees's VLA change results in a warning about a pre-existing condition,
we may decide to apply it as a fix, and handle the conflict with Kees's
patch in cryptodev. Otherwise, I can respin it to apply onto cryptodev
directly. The patch was build tested only - I don't have the hardware.
Thoughts anyone?
drivers/crypto/qat/qat_common/qat_algs.c | 60 ++++++++++----------
1 file changed, 31 insertions(+), 29 deletions(-)
diff --git a/drivers/crypto/qat/qat_common/qat_algs.c b/drivers/crypto/qat/qat_common/qat_algs.c
index 1138e41d6805..d2698299896f 100644
--- a/drivers/crypto/qat/qat_common/qat_algs.c
+++ b/drivers/crypto/qat/qat_common/qat_algs.c
@@ -113,6 +113,13 @@ struct qat_alg_aead_ctx {
struct crypto_shash *hash_tfm;
enum icp_qat_hw_auth_algo qat_hash_alg;
struct qat_crypto_instance *inst;
+ union {
+ struct sha1_state sha1;
+ struct sha256_state sha256;
+ struct sha512_state sha512;
+ };
+ char ipad[SHA512_BLOCK_SIZE]; /* sufficient for SHA-1/SHA-256 as well */
+ char opad[SHA512_BLOCK_SIZE];
};
struct qat_alg_ablkcipher_ctx {
@@ -148,37 +155,32 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
unsigned int auth_keylen)
{
SHASH_DESC_ON_STACK(shash, ctx->hash_tfm);
- struct sha1_state sha1;
- struct sha256_state sha256;
- 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];
__be32 *hash_state_out;
__be64 *hash512_state_out;
int i, offset;
- memset(ipad, 0, block_size);
- memset(opad, 0, block_size);
+ memset(ctx->ipad, 0, block_size);
+ memset(ctx->opad, 0, block_size);
shash->tfm = ctx->hash_tfm;
shash->flags = 0x0;
if (auth_keylen > block_size) {
int ret = crypto_shash_digest(shash, auth_key,
- auth_keylen, ipad);
+ auth_keylen, ctx->ipad);
if (ret)
return ret;
- memcpy(opad, ipad, digest_size);
+ memcpy(ctx->opad, ctx->ipad, digest_size);
} else {
- memcpy(ipad, auth_key, auth_keylen);
- memcpy(opad, auth_key, auth_keylen);
+ memcpy(ctx->ipad, auth_key, auth_keylen);
+ memcpy(ctx->opad, auth_key, auth_keylen);
}
for (i = 0; i < block_size; i++) {
- char *ipad_ptr = ipad + i;
- char *opad_ptr = opad + i;
+ char *ipad_ptr = ctx->ipad + i;
+ char *opad_ptr = ctx->opad + i;
*ipad_ptr ^= HMAC_IPAD_VALUE;
*opad_ptr ^= HMAC_OPAD_VALUE;
}
@@ -186,7 +188,7 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
if (crypto_shash_init(shash))
return -EFAULT;
- if (crypto_shash_update(shash, ipad, block_size))
+ if (crypto_shash_update(shash, ctx->ipad, block_size))
return -EFAULT;
hash_state_out = (__be32 *)hash->sha.state1;
@@ -194,22 +196,22 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
switch (ctx->qat_hash_alg) {
case ICP_QAT_HW_AUTH_ALGO_SHA1:
- if (crypto_shash_export(shash, &sha1))
+ if (crypto_shash_export(shash, &ctx->sha1))
return -EFAULT;
for (i = 0; i < digest_size >> 2; i++, hash_state_out++)
- *hash_state_out = cpu_to_be32(*(sha1.state + i));
+ *hash_state_out = cpu_to_be32(ctx->sha1.state[i]);
break;
case ICP_QAT_HW_AUTH_ALGO_SHA256:
- if (crypto_shash_export(shash, &sha256))
+ if (crypto_shash_export(shash, &ctx->sha256))
return -EFAULT;
for (i = 0; i < digest_size >> 2; i++, hash_state_out++)
- *hash_state_out = cpu_to_be32(*(sha256.state + i));
+ *hash_state_out = cpu_to_be32(ctx->sha256.state[i]);
break;
case ICP_QAT_HW_AUTH_ALGO_SHA512:
- if (crypto_shash_export(shash, &sha512))
+ if (crypto_shash_export(shash, &ctx->sha512))
return -EFAULT;
for (i = 0; i < digest_size >> 3; i++, hash512_state_out++)
- *hash512_state_out = cpu_to_be64(*(sha512.state + i));
+ *hash512_state_out = cpu_to_be64(ctx->sha512.state[i]);
break;
default:
return -EFAULT;
@@ -218,7 +220,7 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
if (crypto_shash_init(shash))
return -EFAULT;
- if (crypto_shash_update(shash, opad, block_size))
+ if (crypto_shash_update(shash, ctx->opad, block_size))
return -EFAULT;
offset = round_up(qat_get_inter_state_size(ctx->qat_hash_alg), 8);
@@ -227,28 +229,28 @@ static int qat_alg_do_precomputes(struct icp_qat_hw_auth_algo_blk *hash,
switch (ctx->qat_hash_alg) {
case ICP_QAT_HW_AUTH_ALGO_SHA1:
- if (crypto_shash_export(shash, &sha1))
+ if (crypto_shash_export(shash, &ctx->sha1))
return -EFAULT;
for (i = 0; i < digest_size >> 2; i++, hash_state_out++)
- *hash_state_out = cpu_to_be32(*(sha1.state + i));
+ *hash_state_out = cpu_to_be32(ctx->sha1.state[i]);
break;
case ICP_QAT_HW_AUTH_ALGO_SHA256:
- if (crypto_shash_export(shash, &sha256))
+ if (crypto_shash_export(shash, &ctx->sha256))
return -EFAULT;
for (i = 0; i < digest_size >> 2; i++, hash_state_out++)
- *hash_state_out = cpu_to_be32(*(sha256.state + i));
+ *hash_state_out = cpu_to_be32(ctx->sha256.state[i]);
break;
case ICP_QAT_HW_AUTH_ALGO_SHA512:
- if (crypto_shash_export(shash, &sha512))
+ if (crypto_shash_export(shash, &ctx->sha512))
return -EFAULT;
for (i = 0; i < digest_size >> 3; i++, hash512_state_out++)
- *hash512_state_out = cpu_to_be64(*(sha512.state + i));
+ *hash512_state_out = cpu_to_be64(ctx->sha512.state[i]);
break;
default:
return -EFAULT;
}
- memzero_explicit(ipad, block_size);
- memzero_explicit(opad, block_size);
+ memzero_explicit(ctx->ipad, block_size);
+ memzero_explicit(ctx->opad, block_size);
return 0;
}
--
2.18.0
