Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/crypto/michael_mic.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 3458 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
2 | * Cryptographic API |
3 | * |
4 | * Michael MIC (IEEE 802.11i/TKIP) keyed digest |
5 | * |
6 | * Copyright (c) 2004 Jouni Malinen <jkmaline@cc.hut.fi> |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License version 2 as |
10 | * published by the Free Software Foundation. |
11 | */ |
12 | |
13 | #include <linux/init.h> |
14 | #include <linux/module.h> |
15 | #include <linux/string.h> |
16 | #include <linux/crypto.h> |
17 | |
18 | |
19 | struct michael_mic_ctx { |
20 | u8 pending[4]; |
21 | size_t pending_len; |
22 | |
23 | u32 l, r; |
24 | }; |
25 | |
26 | |
27 | static inline u32 xswap(u32 val) |
28 | { |
29 | return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8); |
30 | } |
31 | |
32 | |
33 | #define michael_block(l, r) \ |
34 | do { \ |
35 | r ^= rol32(l, 17); \ |
36 | l += r; \ |
37 | r ^= xswap(l); \ |
38 | l += r; \ |
39 | r ^= rol32(l, 3); \ |
40 | l += r; \ |
41 | r ^= ror32(l, 2); \ |
42 | l += r; \ |
43 | } while (0) |
44 | |
45 | |
46 | static inline u32 get_le32(const u8 *p) |
47 | { |
48 | return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24); |
49 | } |
50 | |
51 | |
52 | static inline void put_le32(u8 *p, u32 v) |
53 | { |
54 | p[0] = v; |
55 | p[1] = v >> 8; |
56 | p[2] = v >> 16; |
57 | p[3] = v >> 24; |
58 | } |
59 | |
60 | |
61 | static void michael_init(void *ctx) |
62 | { |
63 | struct michael_mic_ctx *mctx = ctx; |
64 | mctx->pending_len = 0; |
65 | } |
66 | |
67 | |
68 | static void michael_update(void *ctx, const u8 *data, unsigned int len) |
69 | { |
70 | struct michael_mic_ctx *mctx = ctx; |
71 | |
72 | if (mctx->pending_len) { |
73 | int flen = 4 - mctx->pending_len; |
74 | if (flen > len) |
75 | flen = len; |
76 | memcpy(&mctx->pending[mctx->pending_len], data, flen); |
77 | mctx->pending_len += flen; |
78 | data += flen; |
79 | len -= flen; |
80 | |
81 | if (mctx->pending_len < 4) |
82 | return; |
83 | |
84 | mctx->l ^= get_le32(mctx->pending); |
85 | michael_block(mctx->l, mctx->r); |
86 | mctx->pending_len = 0; |
87 | } |
88 | |
89 | while (len >= 4) { |
90 | mctx->l ^= get_le32(data); |
91 | michael_block(mctx->l, mctx->r); |
92 | data += 4; |
93 | len -= 4; |
94 | } |
95 | |
96 | if (len > 0) { |
97 | mctx->pending_len = len; |
98 | memcpy(mctx->pending, data, len); |
99 | } |
100 | } |
101 | |
102 | |
103 | static void michael_final(void *ctx, u8 *out) |
104 | { |
105 | struct michael_mic_ctx *mctx = ctx; |
106 | u8 *data = mctx->pending; |
107 | |
108 | /* Last block and padding (0x5a, 4..7 x 0) */ |
109 | switch (mctx->pending_len) { |
110 | case 0: |
111 | mctx->l ^= 0x5a; |
112 | break; |
113 | case 1: |
114 | mctx->l ^= data[0] | 0x5a00; |
115 | break; |
116 | case 2: |
117 | mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000; |
118 | break; |
119 | case 3: |
120 | mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) | |
121 | 0x5a000000; |
122 | break; |
123 | } |
124 | michael_block(mctx->l, mctx->r); |
125 | /* l ^= 0; */ |
126 | michael_block(mctx->l, mctx->r); |
127 | |
128 | put_le32(out, mctx->l); |
129 | put_le32(out + 4, mctx->r); |
130 | } |
131 | |
132 | |
133 | static int michael_setkey(void *ctx, const u8 *key, unsigned int keylen, |
134 | u32 *flags) |
135 | { |
136 | struct michael_mic_ctx *mctx = ctx; |
137 | if (keylen != 8) { |
138 | if (flags) |
139 | *flags = CRYPTO_TFM_RES_BAD_KEY_LEN; |
140 | return -EINVAL; |
141 | } |
142 | mctx->l = get_le32(key); |
143 | mctx->r = get_le32(key + 4); |
144 | return 0; |
145 | } |
146 | |
147 | |
148 | static struct crypto_alg michael_mic_alg = { |
149 | .cra_name = "michael_mic", |
150 | .cra_flags = CRYPTO_ALG_TYPE_DIGEST, |
151 | .cra_blocksize = 8, |
152 | .cra_ctxsize = sizeof(struct michael_mic_ctx), |
153 | .cra_module = THIS_MODULE, |
154 | .cra_list = LIST_HEAD_INIT(michael_mic_alg.cra_list), |
155 | .cra_u = { .digest = { |
156 | .dia_digestsize = 8, |
157 | .dia_init = michael_init, |
158 | .dia_update = michael_update, |
159 | .dia_final = michael_final, |
160 | .dia_setkey = michael_setkey } } |
161 | }; |
162 | |
163 | |
164 | static int __init michael_mic_init(void) |
165 | { |
166 | return crypto_register_alg(&michael_mic_alg); |
167 | } |
168 | |
169 | |
170 | static void __exit michael_mic_exit(void) |
171 | { |
172 | crypto_unregister_alg(&michael_mic_alg); |
173 | } |
174 | |
175 | |
176 | module_init(michael_mic_init); |
177 | module_exit(michael_mic_exit); |
178 | |
179 | MODULE_LICENSE("GPL v2"); |
180 | MODULE_DESCRIPTION("Michael MIC"); |
181 | MODULE_AUTHOR("Jouni Malinen <jkmaline@cc.hut.fi>"); |