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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>
19
20
21struct michael_mic_ctx {
22 u8 pending[4];
23 size_t pending_len;
24
25 u32 l, r;
26};
27
28
29static inline u32 xswap(u32 val)
30{
31 return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
32}
33
34
35#define michael_block(l, r) \
36do { \
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
48static void michael_init(struct crypto_tfm *tfm)
49{
50 struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
51 mctx->pending_len = 0;
52}
53
54
55static 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;
60
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;
69
70 if (mctx->pending_len < 4)
71 return;
72
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 }
78
79 src = (const __le32 *)data;
80
81 while (len >= 4) {
82 mctx->l ^= le32_to_cpup(src++);
83 michael_block(mctx->l, mctx->r);
84 len -= 4;
85 }
86
87 if (len > 0) {
88 mctx->pending_len = len;
89 memcpy(mctx->pending, src, len);
90 }
91}
92
93
94static 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;
99
100
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
118 michael_block(mctx->l, mctx->r);
119
120 dst[0] = cpu_to_le32(mctx->l);
121 dst[1] = cpu_to_le32(mctx->r);
122}
123
124
125static int michael_setkey(struct crypto_tfm *tfm, const u8 *key,
126 unsigned int keylen)
127{
128 struct michael_mic_ctx *mctx = crypto_tfm_ctx(tfm);
129 const __le32 *data = (const __le32 *)key;
130
131 if (keylen != 8) {
132 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
133 return -EINVAL;
134 }
135
136 mctx->l = le32_to_cpu(data[0]);
137 mctx->r = le32_to_cpu(data[1]);
138 return 0;
139}
140
141
142static 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_alignmask = 3,
149 .cra_list = LIST_HEAD_INIT(michael_mic_alg.cra_list),
150 .cra_u = { .digest = {
151 .dia_digestsize = 8,
152 .dia_init = michael_init,
153 .dia_update = michael_update,
154 .dia_final = michael_final,
155 .dia_setkey = michael_setkey } }
156};
157
158
159static int __init michael_mic_init(void)
160{
161 return crypto_register_alg(&michael_mic_alg);
162}
163
164
165static void __exit michael_mic_exit(void)
166{
167 crypto_unregister_alg(&michael_mic_alg);
168}
169
170
171module_init(michael_mic_init);
172module_exit(michael_mic_exit);
173
174MODULE_LICENSE("GPL v2");
175MODULE_DESCRIPTION("Michael MIC");
176MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");
177