ia64/linux-2.6.18-xen.hg

view crypto/michael_mic.c @ 0:831230e53067

Import 2.6.18 from kernel.org tarball.
author Ian Campbell <ian.campbell@xensource.com>
date Wed Apr 11 14:15:44 2007 +0100 (2007-04-11)
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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 */
13 #include <asm/byteorder.h>
14 #include <linux/init.h>
15 #include <linux/module.h>
16 #include <linux/string.h>
17 #include <linux/crypto.h>
18 #include <linux/types.h>
21 struct michael_mic_ctx {
22 u8 pending[4];
23 size_t pending_len;
25 u32 l, r;
26 };
29 static inline u32 xswap(u32 val)
30 {
31 return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
32 }
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)
48 static void michael_init(struct crypto_tfm *tfm)
49 {
50 struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
51 mctx->pending_len = 0;
52 }
55 static void michael_update(struct crypto_tfm *tfm, const u8 *data,
56 unsigned int len)
57 {
58 struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
59 const __le32 *src;
61 if (mctx->pending_len) {
62 int flen = 4 - mctx->pending_len;
63 if (flen > len)
64 flen = len;
65 memcpy(&mctx->pending[mctx->pending_len], data, flen);
66 mctx->pending_len += flen;
67 data += flen;
68 len -= flen;
70 if (mctx->pending_len < 4)
71 return;
73 src = (const __le32 *)mctx->pending;
74 mctx->l ^= le32_to_cpup(src);
75 michael_block(mctx->l, mctx->r);
76 mctx->pending_len = 0;
77 }
79 src = (const __le32 *)data;
81 while (len >= 4) {
82 mctx->l ^= le32_to_cpup(src++);
83 michael_block(mctx->l, mctx->r);
84 len -= 4;
85 }
87 if (len > 0) {
88 mctx->pending_len = len;
89 memcpy(mctx->pending, src, len);
90 }
91 }
94 static void michael_final(struct crypto_tfm *tfm, u8 *out)
95 {
96 struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
97 u8 *data = mctx->pending;
98 __le32 *dst = (__le32 *)out;
100 /* Last block and padding (0x5a, 4..7 x 0) */
101 switch (mctx->pending_len) {
102 case 0:
103 mctx->l ^= 0x5a;
104 break;
105 case 1:
106 mctx->l ^= data[0] | 0x5a00;
107 break;
108 case 2:
109 mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;
110 break;
111 case 3:
112 mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
113 0x5a000000;
114 break;
115 }
116 michael_block(mctx->l, mctx->r);
117 /* l ^= 0; */
118 michael_block(mctx->l, mctx->r);
120 dst[0] = cpu_to_le32(mctx->l);
121 dst[1] = cpu_to_le32(mctx->r);
122 }
125 static int michael_setkey(struct crypto_tfm *tfm, const u8 *key,
126 unsigned int keylen, u32 *flags)
127 {
128 struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
129 const __le32 *data = (const __le32 *)key;
131 if (keylen != 8) {
132 if (flags)
133 *flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
134 return -EINVAL;
135 }
137 mctx->l = le32_to_cpu(data[0]);
138 mctx->r = le32_to_cpu(data[1]);
139 return 0;
140 }
143 static struct crypto_alg michael_mic_alg = {
144 .cra_name = "michael_mic",
145 .cra_flags = CRYPTO_ALG_TYPE_DIGEST,
146 .cra_blocksize = 8,
147 .cra_ctxsize = sizeof(struct michael_mic_ctx),
148 .cra_module = THIS_MODULE,
149 .cra_alignmask = 3,
150 .cra_list = LIST_HEAD_INIT(michael_mic_alg.cra_list),
151 .cra_u = { .digest = {
152 .dia_digestsize = 8,
153 .dia_init = michael_init,
154 .dia_update = michael_update,
155 .dia_final = michael_final,
156 .dia_setkey = michael_setkey } }
157 };
160 static int __init michael_mic_init(void)
161 {
162 return crypto_register_alg(&michael_mic_alg);
163 }
166 static void __exit michael_mic_exit(void)
167 {
168 crypto_unregister_alg(&michael_mic_alg);
169 }
172 module_init(michael_mic_init);
173 module_exit(michael_mic_exit);
175 MODULE_LICENSE("GPL v2");
176 MODULE_DESCRIPTION("Michael MIC");
177 MODULE_AUTHOR("Jouni Malinen <jkmaline@cc.hut.fi>");