Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/crypto/michael_mic.c

  1 /*
  2  * Cryptographic API
  3  *
  4  * Michael MIC (IEEE 802.11i/TKIP) keyed digest
  5  *
  6  * Copyright (c) 2004 Jouni Malinen <j@w1.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 #include <crypto/internal/hash.h>
 13 #include <asm/byteorder.h>
 14 #include <linux/init.h>
 15 #include <linux/module.h>
 16 #include <linux/string.h>
 17 #include <linux/types.h>
 18 
 19 
 20 struct michael_mic_ctx {
 21         u32 l, r;
 22 };
 23 
 24 struct michael_mic_desc_ctx {
 25         u8 pending[4];
 26         size_t pending_len;
 27 
 28         u32 l, r;
 29 };
 30 
 31 static inline u32 xswap(u32 val)
 32 {
 33         return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
 34 }
 35 
 36 
 37 #define michael_block(l, r)     \
 38 do {                            \
 39         r ^= rol32(l, 17);      \
 40         l += r;                 \
 41         r ^= xswap(l);          \
 42         l += r;                 \
 43         r ^= rol32(l, 3);       \
 44         l += r;                 \
 45         r ^= ror32(l, 2);       \
 46         l += r;                 \
 47 } while (0)
 48 
 49 
 50 static int michael_init(struct shash_desc *desc)
 51 {
 52         struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
 53         struct michael_mic_ctx *ctx = crypto_shash_ctx(desc->tfm);
 54         mctx->pending_len = 0;
 55         mctx->l = ctx->l;
 56         mctx->r = ctx->r;
 57 
 58         return 0;
 59 }
 60 
 61 
 62 static int michael_update(struct shash_desc *desc, const u8 *data,
 63                            unsigned int len)
 64 {
 65         struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
 66         const __le32 *src;
 67 
 68         if (mctx->pending_len) {
 69                 int flen = 4 - mctx->pending_len;
 70                 if (flen > len)
 71                         flen = len;
 72                 memcpy(&mctx->pending[mctx->pending_len], data, flen);
 73                 mctx->pending_len += flen;
 74                 data += flen;
 75                 len -= flen;
 76 
 77                 if (mctx->pending_len < 4)
 78                         return 0;
 79 
 80                 src = (const __le32 *)mctx->pending;
 81                 mctx->l ^= le32_to_cpup(src);
 82                 michael_block(mctx->l, mctx->r);
 83                 mctx->pending_len = 0;
 84         }
 85 
 86         src = (const __le32 *)data;
 87 
 88         while (len >= 4) {
 89                 mctx->l ^= le32_to_cpup(src++);
 90                 michael_block(mctx->l, mctx->r);
 91                 len -= 4;
 92         }
 93 
 94         if (len > 0) {
 95                 mctx->pending_len = len;
 96                 memcpy(mctx->pending, src, len);
 97         }
 98 
 99         return 0;
100 }
101 
102 
103 static int michael_final(struct shash_desc *desc, u8 *out)
104 {
105         struct michael_mic_desc_ctx *mctx = shash_desc_ctx(desc);
106         u8 *data = mctx->pending;
107         __le32 *dst = (__le32 *)out;
108 
109         /* Last block and padding (0x5a, 4..7 x 0) */
110         switch (mctx->pending_len) {
111         case 0:
112                 mctx->l ^= 0x5a;
113                 break;
114         case 1:
115                 mctx->l ^= data[0] | 0x5a00;
116                 break;
117         case 2:
118                 mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;
119                 break;
120         case 3:
121                 mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
122                         0x5a000000;
123                 break;
124         }
125         michael_block(mctx->l, mctx->r);
126         /* l ^= 0; */
127         michael_block(mctx->l, mctx->r);
128 
129         dst[0] = cpu_to_le32(mctx->l);
130         dst[1] = cpu_to_le32(mctx->r);
131 
132         return 0;
133 }
134 
135 
136 static int michael_setkey(struct crypto_shash *tfm, const u8 *key,
137                           unsigned int keylen)
138 {
139         struct michael_mic_ctx *mctx = crypto_shash_ctx(tfm);
140 
141         const __le32 *data = (const __le32 *)key;
142 
143         if (keylen != 8) {
144                 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
145                 return -EINVAL;
146         }
147 
148         mctx->l = le32_to_cpu(data[0]);
149         mctx->r = le32_to_cpu(data[1]);
150         return 0;
151 }
152 
153 static struct shash_alg alg = {
154         .digestsize             =       8,
155         .setkey                 =       michael_setkey,
156         .init                   =       michael_init,
157         .update                 =       michael_update,
158         .final                  =       michael_final,
159         .descsize               =       sizeof(struct michael_mic_desc_ctx),
160         .base                   =       {
161                 .cra_name               =       "michael_mic",
162                 .cra_blocksize          =       8,
163                 .cra_alignmask          =       3,
164                 .cra_ctxsize            =       sizeof(struct michael_mic_ctx),
165                 .cra_module             =       THIS_MODULE,
166         }
167 };
168 
169 static int __init michael_mic_init(void)
170 {
171         return crypto_register_shash(&alg);
172 }
173 
174 
175 static void __exit michael_mic_exit(void)
176 {
177         crypto_unregister_shash(&alg);
178 }
179 
180 
181 module_init(michael_mic_init);
182 module_exit(michael_mic_exit);
183 
184 MODULE_LICENSE("GPL v2");
185 MODULE_DESCRIPTION("Michael MIC");
186 MODULE_AUTHOR("Jouni Malinen <j@w1.fi>");
187 MODULE_ALIAS_CRYPTO("michael_mic");
188 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us