[PATCH crypto-next 17/23] crypto: qce - Remove VLA usage of skcipher

From: Kees Cook
Date: Tue Sep 18 2018 - 22:19:25 EST


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@xxxxxxxxxxxxxx

Cc: Himanshu Jha <himanshujha199640@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
drivers/crypto/qce/ablkcipher.c | 13 ++++++-------
drivers/crypto/qce/cipher.h | 2 +-
2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/crypto/qce/ablkcipher.c b/drivers/crypto/qce/ablkcipher.c
index ea4d96bf47e8..585e1cab9ae3 100644
--- a/drivers/crypto/qce/ablkcipher.c
+++ b/drivers/crypto/qce/ablkcipher.c
@@ -189,7 +189,7 @@ static int qce_ablkcipher_setkey(struct crypto_ablkcipher *ablk, const u8 *key,
memcpy(ctx->enc_key, key, keylen);
return 0;
fallback:
- ret = crypto_skcipher_setkey(ctx->fallback, key, keylen);
+ ret = crypto_sync_skcipher_setkey(ctx->fallback, key, keylen);
if (!ret)
ctx->enc_keylen = keylen;
return ret;
@@ -212,9 +212,9 @@ static int qce_ablkcipher_crypt(struct ablkcipher_request *req, int encrypt)

if (IS_AES(rctx->flags) && ctx->enc_keylen != AES_KEYSIZE_128 &&
ctx->enc_keylen != AES_KEYSIZE_256) {
- SKCIPHER_REQUEST_ON_STACK(subreq, ctx->fallback);
+ SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, ctx->fallback);

- skcipher_request_set_tfm(subreq, ctx->fallback);
+ skcipher_request_set_sync_tfm(subreq, ctx->fallback);
skcipher_request_set_callback(subreq, req->base.flags,
NULL, NULL);
skcipher_request_set_crypt(subreq, req->src, req->dst,
@@ -245,9 +245,8 @@ static int qce_ablkcipher_init(struct crypto_tfm *tfm)
memset(ctx, 0, sizeof(*ctx));
tfm->crt_ablkcipher.reqsize = sizeof(struct qce_cipher_reqctx);

- ctx->fallback = crypto_alloc_skcipher(crypto_tfm_alg_name(tfm), 0,
- CRYPTO_ALG_ASYNC |
- CRYPTO_ALG_NEED_FALLBACK);
+ ctx->fallback = crypto_alloc_sync_skcipher(crypto_tfm_alg_name(tfm),
+ 0, CRYPTO_ALG_NEED_FALLBACK);
return PTR_ERR_OR_ZERO(ctx->fallback);
}

@@ -255,7 +254,7 @@ static void qce_ablkcipher_exit(struct crypto_tfm *tfm)
{
struct qce_cipher_ctx *ctx = crypto_tfm_ctx(tfm);

- crypto_free_skcipher(ctx->fallback);
+ crypto_free_sync_skcipher(ctx->fallback);
}

struct qce_ablkcipher_def {
diff --git a/drivers/crypto/qce/cipher.h b/drivers/crypto/qce/cipher.h
index 2b0278bb6e92..ee055bfe98a0 100644
--- a/drivers/crypto/qce/cipher.h
+++ b/drivers/crypto/qce/cipher.h
@@ -22,7 +22,7 @@
struct qce_cipher_ctx {
u8 enc_key[QCE_MAX_KEY_SIZE];
unsigned int enc_keylen;
- struct crypto_skcipher *fallback;
+ struct crypto_sync_skcipher *fallback;
};

/**
--
2.17.1