1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
|
/*
* Copyright 2003-2004, Instant802 Networks, Inc.
* Copyright 2005, 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/types.h>
#include <linux/netdevice.h>
#include <net/ieee80211.h>
#include "ieee80211_key.h"
#include "aes_ccm.h"
#include "aes.c"
static inline void aes_ccm_prepare(u32 *rk, u8 *b_0, u8 *aad, u8 *b,
u8 *s_0, u8 *a)
{
int i;
ieee80211_aes_encrypt(rk, 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(rk, aad, b);
aad += AES_BLOCK_LEN;
for (i = 0; i < AES_BLOCK_LEN; i++)
aad[i] ^= b[i];
ieee80211_aes_encrypt(rk, 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(rk, b_0, s_0);
}
void ieee80211_aes_ccm_encrypt(u32 *rk, 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;
u8 b[AES_BLOCK_LEN], s_0[AES_BLOCK_LEN], e[AES_BLOCK_LEN];
num_blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
last_len = data_len % AES_BLOCK_LEN;
aes_ccm_prepare(rk, 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(rk, b, b);
b_0[14] = (j >> 8) & 0xff;
b_0[15] = j & 0xff;
ieee80211_aes_encrypt(rk, 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(u32 *rk, 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;
u8 b[AES_BLOCK_LEN], s_0[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
num_blocks = (data_len + AES_BLOCK_LEN - 1) / AES_BLOCK_LEN;
last_len = data_len % AES_BLOCK_LEN;
aes_ccm_prepare(rk, 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(rk, b_0, b);
for (i = 0; i < blen; i++) {
*pos = *cpos++ ^ b[i];
a[i] ^= *pos++;
}
ieee80211_aes_encrypt(rk, a, a);
}
for (i = 0; i < CCMP_MIC_LEN; i++) {
if ((mic[i] ^ s_0[i]) != a[i])
return -1;
}
return 0;
}
|
