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f0706e82 JB |
1 | /* |
2 | * Copyright 2003-2004, Instant802 Networks, Inc. | |
3 | * Copyright 2005-2006, Devicescape Software, Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | ||
172589cc | 10 | #include <linux/kernel.h> |
f0706e82 JB |
11 | #include <linux/types.h> |
12 | #include <linux/crypto.h> | |
13 | #include <linux/err.h> | |
0cd20a27 | 14 | #include <crypto/aes.h> |
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15 | |
16 | #include <net/mac80211.h> | |
2c8dccc7 | 17 | #include "key.h" |
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18 | #include "aes_ccm.h" |
19 | ||
5fdae6b3 | 20 | static void aes_ccm_prepare(struct crypto_cipher *tfm, u8 *scratch, u8 *a) |
f0706e82 JB |
21 | { |
22 | int i; | |
5fdae6b3 | 23 | u8 *b_0, *aad, *b, *s_0; |
f0706e82 | 24 | |
0cd20a27 JB |
25 | b_0 = scratch + 3 * AES_BLOCK_SIZE; |
26 | aad = scratch + 4 * AES_BLOCK_SIZE; | |
5fdae6b3 | 27 | b = scratch; |
0cd20a27 | 28 | s_0 = scratch + AES_BLOCK_SIZE; |
5fdae6b3 HH |
29 | |
30 | crypto_cipher_encrypt_one(tfm, b, b_0); | |
f0706e82 JB |
31 | |
32 | /* Extra Authenticate-only data (always two AES blocks) */ | |
0cd20a27 | 33 | for (i = 0; i < AES_BLOCK_SIZE; i++) |
f0706e82 | 34 | aad[i] ^= b[i]; |
5fdae6b3 | 35 | crypto_cipher_encrypt_one(tfm, b, aad); |
f0706e82 | 36 | |
0cd20a27 | 37 | aad += AES_BLOCK_SIZE; |
f0706e82 | 38 | |
0cd20a27 | 39 | for (i = 0; i < AES_BLOCK_SIZE; i++) |
f0706e82 | 40 | aad[i] ^= b[i]; |
5fdae6b3 | 41 | crypto_cipher_encrypt_one(tfm, a, aad); |
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42 | |
43 | /* Mask out bits from auth-only-b_0 */ | |
44 | b_0[0] &= 0x07; | |
45 | ||
46 | /* S_0 is used to encrypt T (= MIC) */ | |
47 | b_0[14] = 0; | |
48 | b_0[15] = 0; | |
5fdae6b3 | 49 | crypto_cipher_encrypt_one(tfm, s_0, b_0); |
f0706e82 JB |
50 | } |
51 | ||
52 | ||
53 | void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch, | |
feccb466 | 54 | u8 *data, size_t data_len, |
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55 | u8 *cdata, u8 *mic) |
56 | { | |
57 | int i, j, last_len, num_blocks; | |
0915cba3 | 58 | u8 *pos, *cpos, *b, *s_0, *e, *b_0; |
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59 | |
60 | b = scratch; | |
0cd20a27 JB |
61 | s_0 = scratch + AES_BLOCK_SIZE; |
62 | e = scratch + 2 * AES_BLOCK_SIZE; | |
63 | b_0 = scratch + 3 * AES_BLOCK_SIZE; | |
f0706e82 | 64 | |
0cd20a27 JB |
65 | num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE); |
66 | last_len = data_len % AES_BLOCK_SIZE; | |
5fdae6b3 | 67 | aes_ccm_prepare(tfm, scratch, b); |
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68 | |
69 | /* Process payload blocks */ | |
70 | pos = data; | |
71 | cpos = cdata; | |
72 | for (j = 1; j <= num_blocks; j++) { | |
73 | int blen = (j == num_blocks && last_len) ? | |
0cd20a27 | 74 | last_len : AES_BLOCK_SIZE; |
f0706e82 JB |
75 | |
76 | /* Authentication followed by encryption */ | |
77 | for (i = 0; i < blen; i++) | |
78 | b[i] ^= pos[i]; | |
5fdae6b3 | 79 | crypto_cipher_encrypt_one(tfm, b, b); |
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80 | |
81 | b_0[14] = (j >> 8) & 0xff; | |
82 | b_0[15] = j & 0xff; | |
5fdae6b3 | 83 | crypto_cipher_encrypt_one(tfm, e, b_0); |
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84 | for (i = 0; i < blen; i++) |
85 | *cpos++ = *pos++ ^ e[i]; | |
86 | } | |
87 | ||
88 | for (i = 0; i < CCMP_MIC_LEN; i++) | |
89 | mic[i] = b[i] ^ s_0[i]; | |
90 | } | |
91 | ||
92 | ||
93 | int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch, | |
feccb466 | 94 | u8 *cdata, size_t data_len, u8 *mic, u8 *data) |
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95 | { |
96 | int i, j, last_len, num_blocks; | |
0915cba3 | 97 | u8 *pos, *cpos, *b, *s_0, *a, *b_0; |
f0706e82 JB |
98 | |
99 | b = scratch; | |
0cd20a27 JB |
100 | s_0 = scratch + AES_BLOCK_SIZE; |
101 | a = scratch + 2 * AES_BLOCK_SIZE; | |
102 | b_0 = scratch + 3 * AES_BLOCK_SIZE; | |
f0706e82 | 103 | |
0cd20a27 JB |
104 | num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE); |
105 | last_len = data_len % AES_BLOCK_SIZE; | |
5fdae6b3 | 106 | aes_ccm_prepare(tfm, scratch, a); |
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107 | |
108 | /* Process payload blocks */ | |
109 | cpos = cdata; | |
110 | pos = data; | |
111 | for (j = 1; j <= num_blocks; j++) { | |
112 | int blen = (j == num_blocks && last_len) ? | |
0cd20a27 | 113 | last_len : AES_BLOCK_SIZE; |
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114 | |
115 | /* Decryption followed by authentication */ | |
116 | b_0[14] = (j >> 8) & 0xff; | |
117 | b_0[15] = j & 0xff; | |
5fdae6b3 | 118 | crypto_cipher_encrypt_one(tfm, b, b_0); |
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119 | for (i = 0; i < blen; i++) { |
120 | *pos = *cpos++ ^ b[i]; | |
121 | a[i] ^= *pos++; | |
122 | } | |
5fdae6b3 | 123 | crypto_cipher_encrypt_one(tfm, a, a); |
f0706e82 JB |
124 | } |
125 | ||
126 | for (i = 0; i < CCMP_MIC_LEN; i++) { | |
127 | if ((mic[i] ^ s_0[i]) != a[i]) | |
128 | return -1; | |
129 | } | |
130 | ||
131 | return 0; | |
132 | } | |
133 | ||
134 | ||
988c0f72 | 135 | struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[]) |
f0706e82 JB |
136 | { |
137 | struct crypto_cipher *tfm; | |
138 | ||
139 | tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC); | |
1ac62ba7 BH |
140 | if (!IS_ERR(tfm)) |
141 | crypto_cipher_setkey(tfm, key, ALG_CCMP_KEY_LEN); | |
f0706e82 JB |
142 | |
143 | return tfm; | |
144 | } | |
145 | ||
146 | ||
147 | void ieee80211_aes_key_free(struct crypto_cipher *tfm) | |
148 | { | |
ffa56e54 | 149 | crypto_free_cipher(tfm); |
f0706e82 | 150 | } |