[PATCH v2 1/2] chcr_ktls: use AES library for single use cipher

[Ard Biesheuvel]

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.sa...@chelsio.com>
Cc: Vinay Kumar Yadav <vinay.ya...@chelsio.com>
Cc: Rohit Maheshwari <roh...@chelsio.com>
Signed-off-by: Ard Biesheuvel <a...@kernel.org>
---
 drivers/net/ethernet/chelsio/inline_crypto/Kconfig             |  1 +
 drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c | 19 
+++++++------------
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/inline_crypto/Kconfig 
b/drivers/net/ethernet/chelsio/inline_crypto/Kconfig
index bc06e83fd3c6..521955e1f894 100644
--- a/drivers/net/ethernet/chelsio/inline_crypto/Kconfig
+++ b/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
diff --git a/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c 
b/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c
index 5195f692f14d..e9b75cec34db 100644
--- a/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c
+++ b/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);
@@ -30,7 +31,7 @@ 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) {
@@ -91,18 +92,14 @@ 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) {
@@ -111,7 +108,7 @@ 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);
@@ -119,8 +116,6 @@ 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;
 }
-- 
2.17.1