[PATCH v5 10/10] crypto: eip93 - Simplify the check for a valid AES key

[Thomas Huth <thuth@redhat.com>]

From: Thomas Huth <thuth@redhat.com>

eip93_aead_setkey() currently uses aes_expandkey() to check for a valid
AES key, but then does not use the crypto_aes_ctx afterwards anymore,
i.e. this is just a wasteful way of checking the key length, and thus
aes_check_keylen() should be used instead.
This also fixes a potential leak of sensitive data via the stack, since
this function forgot to zeroize crypto_aes_ctx before returning to the
caller.

Suggested-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 drivers/crypto/inside-secure/eip93/eip93-aead.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/crypto/inside-secure/eip93/eip93-aead.c b/drivers/crypto/inside-secure/eip93/eip93-aead.c
index 2bbd0af7b0e0e..0b7a899b14d76 100644
--- a/drivers/crypto/inside-secure/eip93/eip93-aead.c
+++ b/drivers/crypto/inside-secure/eip93/eip93-aead.c
@@ -92,7 +92,6 @@ static int eip93_aead_setkey(struct crypto_aead *ctfm, const u8 *key,
 	struct crypto_tfm *tfm = crypto_aead_tfm(ctfm);
 	struct eip93_crypto_ctx *ctx = crypto_tfm_ctx(tfm);
 	struct crypto_authenc_keys keys;
-	struct crypto_aes_ctx aes;
 	struct sa_record *sa_record = ctx->sa_record;
 	u32 nonce = 0;
 	int ret;
@@ -126,7 +125,7 @@ static int eip93_aead_setkey(struct crypto_aead *ctfm, const u8 *key,
 
 		break;
 	case EIP93_ALG_AES:
-		ret = aes_expandkey(&aes, keys.enckey, keys.enckeylen);
+		ret = aes_check_keylen(keys.enckeylen);
 		if (ret)
 			return ret;
 
-- 
2.55.0