drivers/staging/rtl8192u/ieee80211/michael_mic.c

   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 #include "rtl_crypto.h"
  18
  19
  20 struct michael_mic_ctx {
  21         u8 pending[4];
  22         size_t pending_len;
  23
  24         u32 l, r;
  25 };
  26
  27
  28 static inline u32 rotl(u32 val, int bits)
  29 {
  30         return (val << bits) | (val >> (32 - bits));
  31 }
  32
  33
  34 static inline u32 rotr(u32 val, int bits)
  35 {
  36         return (val >> bits) | (val << (32 - bits));
  37 }
  38
  39
  40 static inline u32 xswap(u32 val)
  41 {
  42         return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
  43 }
  44
  45
  46 #define michael_block(l, r)     \
  47 do {                            \
  48         r ^= rotl(l, 17);       \
  49         l += r;                 \
  50         r ^= xswap(l);          \
  51         l += r;                 \
  52         r ^= rotl(l, 3);        \
  53         l += r;                 \
  54         r ^= rotr(l, 2);        \
  55         l += r;                 \
  56 } while (0)
  57
  58
  59 static inline u32 get_le32(const u8 *p)
  60 {
  61         return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
  62 }
  63
  64
  65 static inline void put_le32(u8 *p, u32 v)
  66 {
  67         p[0] = v;
  68         p[1] = v >> 8;
  69         p[2] = v >> 16;
  70         p[3] = v >> 24;
  71 }
  72
  73
  74 static void michael_init(void *ctx)
  75 {
  76         struct michael_mic_ctx *mctx = ctx;
  77         mctx->pending_len = 0;
  78 }
  79
  80
  81 static void michael_update(void *ctx, const u8 *data, unsigned int len)
  82 {
  83         struct michael_mic_ctx *mctx = ctx;
  84
  85         if (mctx->pending_len) {
  86                 int flen = 4 - mctx->pending_len;
  87                 if (flen > len)
  88                         flen = len;
  89                 memcpy(&mctx->pending[mctx->pending_len], data, flen);
  90                 mctx->pending_len += flen;
  91                 data += flen;
  92                 len -= flen;
  93
  94                 if (mctx->pending_len < 4)
  95                         return;
  96
  97                 mctx->l ^= get_le32(mctx->pending);
  98                 michael_block(mctx->l, mctx->r);
  99                 mctx->pending_len = 0;
 100         }
 101
 102         while (len >= 4) {
 103                 mctx->l ^= get_le32(data);
 104                 michael_block(mctx->l, mctx->r);
 105                 data += 4;
 106                 len -= 4;
 107         }
 108
 109         if (len > 0) {
 110                 mctx->pending_len = len;
 111                 memcpy(mctx->pending, data, len);
 112         }
 113 }
 114
 115
 116 static void michael_final(void *ctx, u8 *out)
 117 {
 118         struct michael_mic_ctx *mctx = ctx;
 119         u8 *data = mctx->pending;
 120
 121         /* Last block and padding (0x5a, 4..7 x 0) */
 122         switch (mctx->pending_len) {
 123         case 0:
 124                 mctx->l ^= 0x5a;
 125                 break;
 126         case 1:
 127                 mctx->l ^= data[0] | 0x5a00;
 128                 break;
 129         case 2:
 130                 mctx->l ^= data[0] | (data[1] << 8) | 0x5a0000;
 131                 break;
 132         case 3:
 133                 mctx->l ^= data[0] | (data[1] << 8) | (data[2] << 16) |
 134                         0x5a000000;
 135                 break;
 136         }
 137         michael_block(mctx->l, mctx->r);
 138         /* l ^= 0; */
 139         michael_block(mctx->l, mctx->r);
 140
 141         put_le32(out, mctx->l);
 142         put_le32(out + 4, mctx->r);
 143 }
 144
 145
 146 static int michael_setkey(void *ctx, const u8 *key, unsigned int keylen,
 147                           u32 *flags)
 148 {
 149         struct michael_mic_ctx *mctx = ctx;
 150         if (keylen != 8) {
 151                 if (flags)
 152                         *flags = CRYPTO_TFM_RES_BAD_KEY_LEN;
 153                 return -EINVAL;
 154         }
 155         mctx->l = get_le32(key);
 156         mctx->r = get_le32(key + 4);
 157         return 0;
 158 }
 159
 160
 161 static struct crypto_alg michael_mic_alg = {
 162         .cra_name       = "michael_mic",
 163         .cra_flags      = CRYPTO_ALG_TYPE_DIGEST,
 164         .cra_blocksize  = 8,
 165         .cra_ctxsize    = sizeof(struct michael_mic_ctx),
 166         .cra_module     = THIS_MODULE,
 167         .cra_list       = LIST_HEAD_INIT(michael_mic_alg.cra_list),
 168         .cra_u          = { .digest = {
 169         .dia_digestsize = 8,
 170         .dia_init       = michael_init,
 171         .dia_update     = michael_update,
 172         .dia_final      = michael_final,
 173         .dia_setkey     = michael_setkey } }
 174 };
 175
 176
 177 static int __init michael_mic_init(void)
 178 {
 179         return crypto_register_alg(&michael_mic_alg);
 180 }
 181
 182
 183 static void __exit michael_mic_exit(void)
 184 {
 185         crypto_unregister_alg(&michael_mic_alg);
 186 }
 187
 188
 189 module_init(michael_mic_init);
 190 module_exit(michael_mic_exit);
 191
 192 MODULE_LICENSE("GPL v2");
 193 MODULE_DESCRIPTION("Michael MIC");
 194 MODULE_AUTHOR("Jouni Malinen <jkmaline@cc.hut.fi>");