crypto: af_alg - use sock_kmemdup in alg_setkey_by_key_serial

Replace sock_kmalloc() followed by memcpy() with sock_kmemdup() to
simplify alg_setkey_by_key_serial().

Signed-off-by: Thorsten Blum <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

Author: toblux

crypto/af_alg.c

@@ -324,15 +324,13 @@ static int alg_setkey_by_key_serial(struct alg_sock *ask, sockptr_t optval,
 		return PTR_ERR(ret);
 	}
 
-	key_data = sock_kmalloc(&ask->sk, key_datalen, GFP_KERNEL);
+	key_data = sock_kmemdup(&ask->sk, ret, key_datalen, GFP_KERNEL);
 	if (!key_data) {
 		up_read(&key->sem);
 		key_put(key);
 		return -ENOMEM;
 	}
 
-	memcpy(key_data, ret, key_datalen);
-
 	up_read(&key->sem);
 	key_put(key);