chcr_ktls: use AES library for single use cipher

Allocating a cipher via the crypto API only to free it again after using
it to encrypt a single block is unnecessary in cases where the algorithm
is known at compile time. So replace this pattern with a call to the AES
library.

Cc: Ayush Sawal <ayush.sawal@chelsio.com>
Cc: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Cc: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/net/ethernet/chelsio/inline_crypto/Kconfig

@@ -42,6 +42,7 @@ config CHELSIO_TLS_DEVICE
         depends on CHELSIO_T4
         depends on TLS
         depends on TLS_DEVICE
+	select CRYPTO_LIB_AES
         help
           This flag enables support for kernel tls offload over Chelsio T6
           crypto accelerator. CONFIG_CHELSIO_TLS_DEVICE flag can be enabled

drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c

@@ -9,6 +9,7 @@
 #include <linux/ip.h>
 #include <net/ipv6.h>
 #include <linux/netdevice.h>
+#include <crypto/aes.h>
 #include "chcr_ktls.h"
 
 static LIST_HEAD(uld_ctx_list);
@@ -74,7 +75,7 @@ static int chcr_ktls_save_keys(struct chcr_ktls_info *tx_info,
 	unsigned char ghash_h[TLS_CIPHER_AES_GCM_256_TAG_SIZE];
 	struct tls12_crypto_info_aes_gcm_128 *info_128_gcm;
 	struct ktls_key_ctx *kctx = &tx_info->key_ctx;
-	struct crypto_cipher *cipher;
+	struct crypto_aes_ctx aes_ctx;
 	unsigned char *key, *salt;
 
 	switch (crypto_info->cipher_type) {
@@ -135,18 +136,14 @@ static int chcr_ktls_save_keys(struct chcr_ktls_info *tx_info,
 	/* Calculate the H = CIPH(K, 0 repeated 16 times).
 	 * It will go in key context
 	 */
-	cipher = crypto_alloc_cipher("aes", 0, 0);
-	if (IS_ERR(cipher)) {
-		ret = -ENOMEM;
-		goto out;
-	}
 
-	ret = crypto_cipher_setkey(cipher, key, keylen);
+	ret = aes_expandkey(&aes_ctx, key, keylen);
 	if (ret)
-		goto out1;
+		goto out;
 
 	memset(ghash_h, 0, ghash_size);
-	crypto_cipher_encrypt_one(cipher, ghash_h, ghash_h);
+	aes_encrypt(&aes_ctx, ghash_h, ghash_h);
+	memzero_explicit(&aes_ctx, sizeof(aes_ctx));
 
 	/* fill the Key context */
 	if (direction == TLS_OFFLOAD_CTX_DIR_TX) {
@@ -155,7 +152,7 @@ static int chcr_ktls_save_keys(struct chcr_ktls_info *tx_info,
 						 key_ctx_size >> 4);
 	} else {
 		ret = -EINVAL;
-		goto out1;
+		goto out;
 	}
 
 	memcpy(kctx->salt, salt, tx_info->salt_size);
@@ -163,8 +160,6 @@ static int chcr_ktls_save_keys(struct chcr_ktls_info *tx_info,
 	memcpy(kctx->key + keylen, ghash_h, ghash_size);
 	tx_info->key_ctx_len = key_ctx_size;
 
-out1:
-	crypto_free_cipher(cipher);
 out:
 	return ret;
 }