Commit | Line | Data |
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1da177e4 LT |
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 | ||
06ace7a9 | 13 | #include <asm/byteorder.h> |
1da177e4 LT |
14 | #include <linux/init.h> |
15 | #include <linux/module.h> | |
16 | #include <linux/string.h> | |
17 | #include <linux/crypto.h> | |
06ace7a9 | 18 | #include <linux/types.h> |
1da177e4 LT |
19 | |
20 | ||
21 | struct michael_mic_ctx { | |
22 | u8 pending[4]; | |
23 | size_t pending_len; | |
24 | ||
25 | u32 l, r; | |
26 | }; | |
27 | ||
28 | ||
29 | static inline u32 xswap(u32 val) | |
30 | { | |
31 | return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8); | |
32 | } | |
33 | ||
34 | ||
35 | #define michael_block(l, r) \ | |
36 | do { \ | |
37 | r ^= rol32(l, 17); \ | |
38 | l += r; \ | |
39 | r ^= xswap(l); \ | |
40 | l += r; \ | |
41 | r ^= rol32(l, 3); \ | |
42 | l += r; \ | |
43 | r ^= ror32(l, 2); \ | |
44 | l += r; \ | |
45 | } while (0) | |
46 | ||
47 | ||
1da177e4 LT |
48 | static void michael_init(void *ctx) |
49 | { | |
50 | struct michael_mic_ctx *mctx = ctx; | |
51 | mctx->pending_len = 0; | |
52 | } | |
53 | ||
54 | ||
55 | static void michael_update(void *ctx, const u8 *data, unsigned int len) | |
56 | { | |
57 | struct michael_mic_ctx *mctx = ctx; | |
06ace7a9 | 58 | const __le32 *src; |
1da177e4 LT |
59 | |
60 | if (mctx->pending_len) { | |
61 | int flen = 4 - mctx->pending_len; | |
62 | if (flen > len) | |
63 | flen = len; | |
64 | memcpy(&mctx->pending[mctx->pending_len], data, flen); | |
65 | mctx->pending_len += flen; | |
66 | data += flen; | |
67 | len -= flen; | |
68 | ||
69 | if (mctx->pending_len < 4) | |
70 | return; | |
71 | ||
06ace7a9 HX |
72 | src = (const __le32 *)mctx->pending; |
73 | mctx->l ^= le32_to_cpup(src); | |
1da177e4 LT |
74 | michael_block(mctx->l, mctx->r); |
75 | mctx->pending_len = 0; | |
76 | } | |
77 | ||
06ace7a9 HX |
78 | src = (const __le32 *)data; |
79 | ||
1da177e4 | 80 | while (len >= 4) { |
06ace7a9 | 81 | mctx->l ^= le32_to_cpup(src++); |
1da177e4 | 82 | michael_block(mctx->l, mctx->r); |
1da177e4 LT |
83 | len -= 4; |
84 | } | |
85 | ||
86 | if (len > 0) { | |
87 | mctx->pending_len = len; | |
06ace7a9 | 88 | memcpy(mctx->pending, src, len); |
1da177e4 LT |
89 | } |
90 | } | |
91 | ||
92 | ||
93 | static void michael_final(void *ctx, u8 *out) | |
94 | { | |
95 | struct michael_mic_ctx *mctx = ctx; | |
96 | u8 *data = mctx->pending; | |
06ace7a9 | 97 | __le32 *dst = (__le32 *)out; |
1da177e4 LT |
98 | |
99 | /* Last block and padding (0x5a, 4..7 x 0) */ | |
100 | switch (mctx->pending_len) { | |
101 | case 0: | |
102 | mctx->l ^= 0x5a; | |
103 | break; | |
104 | case 1: | |
105 | mctx->l ^= data[0] | 0x5a00; | |
106 | break; | |
107 | case 2: | |
108 | mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000; | |
109 | break; | |
110 | case 3: | |
111 | mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) | | |
112 | 0x5a000000; | |
113 | break; | |
114 | } | |
115 | michael_block(mctx->l, mctx->r); | |
116 | /* l ^= 0; */ | |
117 | michael_block(mctx->l, mctx->r); | |
118 | ||
06ace7a9 HX |
119 | dst[0] = cpu_to_le32(mctx->l); |
120 | dst[1] = cpu_to_le32(mctx->r); | |
1da177e4 LT |
121 | } |
122 | ||
123 | ||
124 | static int michael_setkey(void *ctx, const u8 *key, unsigned int keylen, | |
125 | u32 *flags) | |
126 | { | |
127 | struct michael_mic_ctx *mctx = ctx; | |
06ace7a9 HX |
128 | const __le32 *data = (const __le32 *)key; |
129 | ||
1da177e4 LT |
130 | if (keylen != 8) { |
131 | if (flags) | |
132 | *flags = CRYPTO_TFM_RES_BAD_KEY_LEN; | |
133 | return -EINVAL; | |
134 | } | |
06ace7a9 HX |
135 | |
136 | mctx->l = le32_to_cpu(data[0]); | |
137 | mctx->r = le32_to_cpu(data[1]); | |
1da177e4 LT |
138 | return 0; |
139 | } | |
140 | ||
141 | ||
142 | static struct crypto_alg michael_mic_alg = { | |
143 | .cra_name = "michael_mic", | |
144 | .cra_flags = CRYPTO_ALG_TYPE_DIGEST, | |
145 | .cra_blocksize = 8, | |
146 | .cra_ctxsize = sizeof(struct michael_mic_ctx), | |
147 | .cra_module = THIS_MODULE, | |
148 | .cra_list = LIST_HEAD_INIT(michael_mic_alg.cra_list), | |
149 | .cra_u = { .digest = { | |
150 | .dia_digestsize = 8, | |
151 | .dia_init = michael_init, | |
152 | .dia_update = michael_update, | |
153 | .dia_final = michael_final, | |
154 | .dia_setkey = michael_setkey } } | |
155 | }; | |
156 | ||
157 | ||
158 | static int __init michael_mic_init(void) | |
159 | { | |
160 | return crypto_register_alg(&michael_mic_alg); | |
161 | } | |
162 | ||
163 | ||
164 | static void __exit michael_mic_exit(void) | |
165 | { | |
166 | crypto_unregister_alg(&michael_mic_alg); | |
167 | } | |
168 | ||
169 | ||
170 | module_init(michael_mic_init); | |
171 | module_exit(michael_mic_exit); | |
172 | ||
173 | MODULE_LICENSE("GPL v2"); | |
174 | MODULE_DESCRIPTION("Michael MIC"); | |
175 | MODULE_AUTHOR("Jouni Malinen <jkmaline@cc.hut.fi>"); |