2 * Copyright 2003-2004, Instant802 Networks, Inc.
3 * Copyright 2005-2006, Devicescape Software, Inc.
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.
10 #include <linux/kernel.h>
11 #include <linux/types.h>
12 #include <linux/crypto.h>
13 #include <linux/err.h>
15 #include <net/mac80211.h>
20 static void ieee80211_aes_encrypt(struct crypto_cipher *tfm,
21 const u8 pt[16], u8 ct[16])
23 crypto_cipher_encrypt_one(tfm, ct, pt);
27 static inline void aes_ccm_prepare(struct crypto_cipher *tfm, u8 *b_0, u8 *aad,
28 u8 *b, u8 *s_0, u8 *a)
32 ieee80211_aes_encrypt(tfm, b_0, b);
34 /* Extra Authenticate-only data (always two AES blocks) */
35 for (i = 0; i < AES_BLOCK_LEN; i++)
37 ieee80211_aes_encrypt(tfm, aad, b);
41 for (i = 0; i < AES_BLOCK_LEN; i++)
43 ieee80211_aes_encrypt(tfm, aad, a);
45 /* Mask out bits from auth-only-b_0 */
48 /* S_0 is used to encrypt T (= MIC) */
51 ieee80211_aes_encrypt(tfm, b_0, s_0);
55 void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch,
56 u8 *data, size_t data_len,
59 int i, j, last_len, num_blocks;
60 u8 *pos, *cpos, *b, *s_0, *e, *b_0, *aad;
63 s_0 = scratch + AES_BLOCK_LEN;
64 e = scratch + 2 * AES_BLOCK_LEN;
65 b_0 = scratch + 3 * AES_BLOCK_LEN;
66 aad = scratch + 4 * AES_BLOCK_LEN;
68 num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
69 last_len = data_len % AES_BLOCK_LEN;
70 aes_ccm_prepare(tfm, b_0, aad, b, s_0, b);
72 /* Process payload blocks */
75 for (j = 1; j <= num_blocks; j++) {
76 int blen = (j == num_blocks && last_len) ?
77 last_len : AES_BLOCK_LEN;
79 /* Authentication followed by encryption */
80 for (i = 0; i < blen; i++)
82 ieee80211_aes_encrypt(tfm, b, b);
84 b_0[14] = (j >> 8) & 0xff;
86 ieee80211_aes_encrypt(tfm, b_0, e);
87 for (i = 0; i < blen; i++)
88 *cpos++ = *pos++ ^ e[i];
91 for (i = 0; i < CCMP_MIC_LEN; i++)
92 mic[i] = b[i] ^ s_0[i];
96 int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch,
97 u8 *cdata, size_t data_len, u8 *mic, u8 *data)
99 int i, j, last_len, num_blocks;
100 u8 *pos, *cpos, *b, *s_0, *a, *b_0, *aad;
103 s_0 = scratch + AES_BLOCK_LEN;
104 a = scratch + 2 * AES_BLOCK_LEN;
105 b_0 = scratch + 3 * AES_BLOCK_LEN;
106 aad = scratch + 4 * AES_BLOCK_LEN;
108 num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);
109 last_len = data_len % AES_BLOCK_LEN;
110 aes_ccm_prepare(tfm, b_0, aad, b, s_0, a);
112 /* Process payload blocks */
115 for (j = 1; j <= num_blocks; j++) {
116 int blen = (j == num_blocks && last_len) ?
117 last_len : AES_BLOCK_LEN;
119 /* Decryption followed by authentication */
120 b_0[14] = (j >> 8) & 0xff;
122 ieee80211_aes_encrypt(tfm, b_0, b);
123 for (i = 0; i < blen; i++) {
124 *pos = *cpos++ ^ b[i];
128 ieee80211_aes_encrypt(tfm, a, a);
131 for (i = 0; i < CCMP_MIC_LEN; i++) {
132 if ((mic[i] ^ s_0[i]) != a[i])
140 struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[])
142 struct crypto_cipher *tfm;
144 tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
148 crypto_cipher_setkey(tfm, key, ALG_CCMP_KEY_LEN);
154 void ieee80211_aes_key_free(struct crypto_cipher *tfm)
157 crypto_free_cipher(tfm);