156 lines
3.4 KiB
C
156 lines
3.4 KiB
C
/*
|
|
* Copyright 2003-2004, Instant802 Networks, Inc.
|
|
* Copyright 2005-2006, Devicescape Software, Inc.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/types.h>
|
|
#include <linux/crypto.h>
|
|
#include <linux/err.h>
|
|
|
|
#include <net/mac80211.h>
|
|
#include "key.h"
|
|
#include "aes_ccm.h"
|
|
|
|
|
|
static void ieee80211_aes_encrypt(struct crypto_cipher *tfm,
|
|
const u8 pt[16], u8 ct[16])
|
|
{
|
|
crypto_cipher_encrypt_one(tfm, ct, pt);
|
|
}
|
|
|
|
|
|
static inline void aes_ccm_prepare(struct crypto_cipher *tfm, u8 *b_0, u8 *aad,
|
|
u8 *b, u8 *s_0, u8 *a)
|
|
{
|
|
int i;
|
|
|
|
ieee80211_aes_encrypt(tfm, b_0, b);
|
|
|
|
/* Extra Authenticate-only data (always two AES blocks) */
|
|
for (i = 0; i < AES_BLOCK_LEN; i++)
|
|
aad[i] ^= b[i];
|
|
ieee80211_aes_encrypt(tfm, aad, b);
|
|
|
|
aad += AES_BLOCK_LEN;
|
|
|
|
for (i = 0; i < AES_BLOCK_LEN; i++)
|
|
aad[i] ^= b[i];
|
|
ieee80211_aes_encrypt(tfm, aad, a);
|
|
|
|
/* Mask out bits from auth-only-b_0 */
|
|
b_0[0] &= 0x07;
|
|
|
|
/* S_0 is used to encrypt T (= MIC) */
|
|
b_0[14] = 0;
|
|
b_0[15] = 0;
|
|
ieee80211_aes_encrypt(tfm, b_0, s_0);
|
|
}
|
|
|
|
|
|
void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch,
|
|
u8 *b_0, u8 *aad, u8 *data, size_t data_len,
|
|
u8 *cdata, u8 *mic)
|
|
{
|
|
int i, j, last_len, num_blocks;
|
|
u8 *pos, *cpos, *b, *s_0, *e;
|
|
|
|
b = scratch;
|
|
s_0 = scratch + AES_BLOCK_LEN;
|
|
e = scratch + 2 * AES_BLOCK_LEN;
|
|
|
|
num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
|
|
last_len = data_len % AES_BLOCK_LEN;
|
|
aes_ccm_prepare(tfm, b_0, aad, b, s_0, b);
|
|
|
|
/* Process payload blocks */
|
|
pos = data;
|
|
cpos = cdata;
|
|
for (j = 1; j <= num_blocks; j++) {
|
|
int blen = (j == num_blocks && last_len) ?
|
|
last_len : AES_BLOCK_LEN;
|
|
|
|
/* Authentication followed by encryption */
|
|
for (i = 0; i < blen; i++)
|
|
b[i] ^= pos[i];
|
|
ieee80211_aes_encrypt(tfm, b, b);
|
|
|
|
b_0[14] = (j >> 8) & 0xff;
|
|
b_0[15] = j & 0xff;
|
|
ieee80211_aes_encrypt(tfm, b_0, e);
|
|
for (i = 0; i < blen; i++)
|
|
*cpos++ = *pos++ ^ e[i];
|
|
}
|
|
|
|
for (i = 0; i < CCMP_MIC_LEN; i++)
|
|
mic[i] = b[i] ^ s_0[i];
|
|
}
|
|
|
|
|
|
int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch,
|
|
u8 *b_0, u8 *aad, u8 *cdata, size_t data_len,
|
|
u8 *mic, u8 *data)
|
|
{
|
|
int i, j, last_len, num_blocks;
|
|
u8 *pos, *cpos, *b, *s_0, *a;
|
|
|
|
b = scratch;
|
|
s_0 = scratch + AES_BLOCK_LEN;
|
|
a = scratch + 2 * AES_BLOCK_LEN;
|
|
|
|
num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
|
|
last_len = data_len % AES_BLOCK_LEN;
|
|
aes_ccm_prepare(tfm, b_0, aad, b, s_0, a);
|
|
|
|
/* Process payload blocks */
|
|
cpos = cdata;
|
|
pos = data;
|
|
for (j = 1; j <= num_blocks; j++) {
|
|
int blen = (j == num_blocks && last_len) ?
|
|
last_len : AES_BLOCK_LEN;
|
|
|
|
/* Decryption followed by authentication */
|
|
b_0[14] = (j >> 8) & 0xff;
|
|
b_0[15] = j & 0xff;
|
|
ieee80211_aes_encrypt(tfm, b_0, b);
|
|
for (i = 0; i < blen; i++) {
|
|
*pos = *cpos++ ^ b[i];
|
|
a[i] ^= *pos++;
|
|
}
|
|
|
|
ieee80211_aes_encrypt(tfm, a, a);
|
|
}
|
|
|
|
for (i = 0; i < CCMP_MIC_LEN; i++) {
|
|
if ((mic[i] ^ s_0[i]) != a[i])
|
|
return -1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
struct crypto_cipher * ieee80211_aes_key_setup_encrypt(const u8 key[])
|
|
{
|
|
struct crypto_cipher *tfm;
|
|
|
|
tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
|
|
if (IS_ERR(tfm))
|
|
return NULL;
|
|
|
|
crypto_cipher_setkey(tfm, key, ALG_CCMP_KEY_LEN);
|
|
|
|
return tfm;
|
|
}
|
|
|
|
|
|
void ieee80211_aes_key_free(struct crypto_cipher *tfm)
|
|
{
|
|
if (tfm)
|
|
crypto_free_cipher(tfm);
|
|
}
|