/*
- * AES key unwrap (128-bit KEK, RFC3394)
+ * AES key unwrap (RFC3394)
*
* Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * Alternatively, this software may be distributed under the terms of BSD
- * license.
- *
- * See README and COPYING for more details.
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
*/
#include "includes.h"
#include "aes_wrap.h"
/**
- * aes_unwrap - Unwrap key with AES Key Wrap Algorithm (128-bit KEK) (RFC3394)
+ * aes_unwrap - Unwrap key with AES Key Wrap Algorithm (RFC3394)
* @kek: Key encryption key (KEK)
+ * @kek_len: Length of KEK in octets
* @n: Length of the plaintext key in 64-bit units; e.g., 2 = 128-bit = 16
* bytes
* @cipher: Wrapped key to be unwrapped, (n + 1) * 64 bits
* @plain: Plaintext key, n * 64 bits
* Returns: 0 on success, -1 on failure (e.g., integrity verification failed)
*/
-int aes_unwrap(const u8 *kek, int n, const u8 *cipher, u8 *plain)
+int aes_unwrap(const u8 *kek, size_t kek_len, int n, const u8 *cipher,
+ u8 *plain)
{
- u8 a[8], *r, b[16];
+ u8 a[8], *r, b[AES_BLOCK_SIZE];
int i, j;
void *ctx;
+ unsigned int t;
/* 1) Initialize variables. */
os_memcpy(a, cipher, 8);
r = plain;
os_memcpy(r, cipher + 8, 8 * n);
- ctx = aes_decrypt_init(kek, 16);
+ ctx = aes_decrypt_init(kek, kek_len);
if (ctx == NULL)
return -1;
r = plain + (n - 1) * 8;
for (i = n; i >= 1; i--) {
os_memcpy(b, a, 8);
- b[7] ^= n * j + i;
+ t = n * j + i;
+ b[7] ^= t;
+ b[6] ^= t >> 8;
+ b[5] ^= t >> 16;
+ b[4] ^= t >> 24;
os_memcpy(b + 8, r, 8);
aes_decrypt(ctx, b, b);