tls: return -EFAULT if copy_to_user() fails

The copy_to_user() function returns the number of bytes remaining but we
want to return -EFAULT here.

Fixes: 3c4d7559 ("tls: kernel TLS support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tls/tls_main.c

@@ -273,7 +273,8 @@ static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval,
 	}
 
 	if (len == sizeof(crypto_info)) {
-		rc = copy_to_user(optval, crypto_info, sizeof(*crypto_info));
+		if (copy_to_user(optval, crypto_info, sizeof(*crypto_info)))
+			rc = -EFAULT;
 		goto out;
 	}
 
@@ -293,9 +294,10 @@ static int do_tls_getsockopt_tx(struct sock *sk, char __user *optval,
 		memcpy(crypto_info_aes_gcm_128->iv, ctx->iv,
 		       TLS_CIPHER_AES_GCM_128_IV_SIZE);
 		release_sock(sk);
-		rc = copy_to_user(optval,
+		if (copy_to_user(optval,
 				 crypto_info_aes_gcm_128,
-				  sizeof(*crypto_info_aes_gcm_128));
+				 sizeof(*crypto_info_aes_gcm_128)))
+			rc = -EFAULT;
 		break;
 	}
 	default: