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Subject[PATCH crypto-next 12/23] crypto: ccp - Remove VLA usage of skcipher
Date
In the quest to remove all stack VLA usage from the kernel[1], this
replaces struct crypto_skcipher and SKCIPHER_REQUEST_ON_STACK() usage
with struct crypto_sync_skcipher and SYNC_SKCIPHER_REQUEST_ON_STACK(),
which uses a fixed stack size.

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

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gary Hook <gary.hook@amd.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
drivers/crypto/ccp/ccp-crypto-aes-xts.c | 13 +++++++------
drivers/crypto/ccp/ccp-crypto.h | 2 +-
2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/crypto/ccp/ccp-crypto-aes-xts.c b/drivers/crypto/ccp/ccp-crypto-aes-xts.c
index 94b5bcf5b628..ca4630b8395f 100644
--- a/drivers/crypto/ccp/ccp-crypto-aes-xts.c
+++ b/drivers/crypto/ccp/ccp-crypto-aes-xts.c
@@ -102,7 +102,7 @@ static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
ctx->u.aes.key_len = key_len / 2;
sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);

- return crypto_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
+ return crypto_sync_skcipher_setkey(ctx->u.aes.tfm_skcipher, key, key_len);
}

static int ccp_aes_xts_crypt(struct ablkcipher_request *req,
@@ -151,12 +151,13 @@ static int ccp_aes_xts_crypt(struct ablkcipher_request *req,
(ctx->u.aes.key_len != AES_KEYSIZE_256))
fallback = 1;
if (fallback) {
- SKCIPHER_REQUEST_ON_STACK(subreq, ctx->u.aes.tfm_skcipher);
+ SYNC_SKCIPHER_REQUEST_ON_STACK(subreq,
+ ctx->u.aes.tfm_skcipher);

/* Use the fallback to process the request for any
* unsupported unit sizes or key sizes
*/
- skcipher_request_set_tfm(subreq, ctx->u.aes.tfm_skcipher);
+ skcipher_request_set_sync_tfm(subreq, ctx->u.aes.tfm_skcipher);
skcipher_request_set_callback(subreq, req->base.flags,
NULL, NULL);
skcipher_request_set_crypt(subreq, req->src, req->dst,
@@ -203,12 +204,12 @@ static int ccp_aes_xts_decrypt(struct ablkcipher_request *req)
static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm)
{
struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
- struct crypto_skcipher *fallback_tfm;
+ struct crypto_sync_skcipher *fallback_tfm;

ctx->complete = ccp_aes_xts_complete;
ctx->u.aes.key_len = 0;

- fallback_tfm = crypto_alloc_skcipher("xts(aes)", 0,
+ fallback_tfm = crypto_alloc_sync_skcipher("xts(aes)", 0,
CRYPTO_ALG_ASYNC |
CRYPTO_ALG_NEED_FALLBACK);
if (IS_ERR(fallback_tfm)) {
@@ -226,7 +227,7 @@ static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm)
{
struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);

- crypto_free_skcipher(ctx->u.aes.tfm_skcipher);
+ crypto_free_sync_skcipher(ctx->u.aes.tfm_skcipher);
}

static int ccp_register_aes_xts_alg(struct list_head *head,
diff --git a/drivers/crypto/ccp/ccp-crypto.h b/drivers/crypto/ccp/ccp-crypto.h
index b9fd090c46c2..28819e11db96 100644
--- a/drivers/crypto/ccp/ccp-crypto.h
+++ b/drivers/crypto/ccp/ccp-crypto.h
@@ -88,7 +88,7 @@ static inline struct ccp_crypto_ahash_alg *
/***** AES related defines *****/
struct ccp_aes_ctx {
/* Fallback cipher for XTS with unsupported unit sizes */
- struct crypto_skcipher *tfm_skcipher;
+ struct crypto_sync_skcipher *tfm_skcipher;

/* Cipher used to generate CMAC K1/K2 keys */
struct crypto_cipher *tfm_cipher;
--
2.17.1
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