drivers/staging/wlan-ng/p80211wep.c

   1 /* src/p80211/p80211wep.c
   2 *
   3 * WEP encode/decode for P80211.
   4 *
   5 * Copyright (C) 2002 AbsoluteValue Systems, Inc.  All Rights Reserved.
   6 * --------------------------------------------------------------------
   7 *
   8 * linux-wlan
   9 *
  10 *   The contents of this file are subject to the Mozilla Public
  11 *   License Version 1.1 (the "License"); you may not use this file
  12 *   except in compliance with the License. You may obtain a copy of
  13 *   the License at http://www.mozilla.org/MPL/
  14 *
  15 *   Software distributed under the License is distributed on an "AS
  16 *   IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  17 *   implied. See the License for the specific language governing
  18 *   rights and limitations under the License.
  19 *
  20 *   Alternatively, the contents of this file may be used under the
  21 *   terms of the GNU Public License version 2 (the "GPL"), in which
  22 *   case the provisions of the GPL are applicable instead of the
  23 *   above.  If you wish to allow the use of your version of this file
  24 *   only under the terms of the GPL and not to allow others to use
  25 *   your version of this file under the MPL, indicate your decision
  26 *   by deleting the provisions above and replace them with the notice
  27 *   and other provisions required by the GPL.  If you do not delete
  28 *   the provisions above, a recipient may use your version of this
  29 *   file under either the MPL or the GPL.
  30 *
  31 * --------------------------------------------------------------------
  32 *
  33 * Inquiries regarding the linux-wlan Open Source project can be
  34 * made directly to:
  35 *
  36 * AbsoluteValue Systems Inc.
  37 * info@linux-wlan.com
  38 * http://www.linux-wlan.com
  39 *
  40 * --------------------------------------------------------------------
  41 *
  42 * Portions of the development of this software were funded by
  43 * Intersil Corporation as part of PRISM(R) chipset product development.
  44 *
  45 * --------------------------------------------------------------------
  46 */
  47
  48 /*================================================================*/
  49 /* System Includes */
  50
  51 #include <linux/netdevice.h>
  52 #include <linux/wireless.h>
  53 #include <linux/random.h>
  54 #include <linux/kernel.h>
  55
  56
  57 #include "p80211hdr.h"
  58 #include "p80211types.h"
  59 #include "p80211msg.h"
  60 #include "p80211conv.h"
  61 #include "p80211netdev.h"
  62
  63 #define WEP_KEY(x)       (((x) & 0xC0) >> 6)
  64
  65 static const u32 wep_crc32_table[256] = {
  66         0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
  67         0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
  68         0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
  69         0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
  70         0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
  71         0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
  72         0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
  73         0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
  74         0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
  75         0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
  76         0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
  77         0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
  78         0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
  79         0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
  80         0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
  81         0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
  82         0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
  83         0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
  84         0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
  85         0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
  86         0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
  87         0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
  88         0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
  89         0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
  90         0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
  91         0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
  92         0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
  93         0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
  94         0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
  95         0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
  96         0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
  97         0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
  98         0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
  99         0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
 100         0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
 101         0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
 102         0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
 103         0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
 104         0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
 105         0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
 106         0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
 107         0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
 108         0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
 109         0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
 110         0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
 111         0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
 112         0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
 113         0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
 114         0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
 115         0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
 116         0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
 117         0x2d02ef8dL
 118 };
 119
 120 /* keylen in bytes! */
 121
 122 int wep_change_key(wlandevice_t *wlandev, int keynum, u8 *key, int keylen)
 123 {
 124         if (keylen < 0)
 125                 return -1;
 126         if (keylen >= MAX_KEYLEN)
 127                 return -1;
 128         if (key == NULL)
 129                 return -1;
 130         if (keynum < 0)
 131                 return -1;
 132         if (keynum >= NUM_WEPKEYS)
 133                 return -1;
 134
 135
 136         wlandev->wep_keylens[keynum] = keylen;
 137         memcpy(wlandev->wep_keys[keynum], key, keylen);
 138
 139         return 0;
 140 }
 141
 142 /*
 143   4-byte IV at start of buffer, 4-byte ICV at end of buffer.
 144   if successful, buf start is payload begin, length -= 8;
 145  */
 146 int wep_decrypt(wlandevice_t *wlandev, u8 *buf, u32 len, int key_override,
 147                 u8 *iv, u8 *icv)
 148 {
 149         u32 i, j, k, crc, keylen;
 150         u8 s[256], key[64], c_crc[4];
 151         u8 keyidx;
 152
 153         /* Needs to be at least 8 bytes of payload */
 154         if (len <= 0)
 155                 return -1;
 156
 157         /* initialize the first bytes of the key from the IV */
 158         key[0] = iv[0];
 159         key[1] = iv[1];
 160         key[2] = iv[2];
 161         keyidx = WEP_KEY(iv[3]);
 162
 163         if (key_override >= 0)
 164                 keyidx = key_override;
 165
 166         if (keyidx >= NUM_WEPKEYS)
 167                 return -2;
 168
 169         keylen = wlandev->wep_keylens[keyidx];
 170
 171         if (keylen == 0)
 172                 return -3;
 173
 174         /* copy the rest of the key over from the designated key */
 175         memcpy(key + 3, wlandev->wep_keys[keyidx], keylen);
 176
 177         keylen += 3;            /* add in IV bytes */
 178
 179
 180         /* set up the RC4 state */
 181         for (i = 0; i < 256; i++)
 182                 s[i] = i;
 183         j = 0;
 184         for (i = 0; i < 256; i++) {
 185                 j = (j + s[i] + key[i % keylen]) & 0xff;
 186                 swap(i, j);
 187         }
 188
 189         /* Apply the RC4 to the data, update the CRC32 */
 190         crc = ~0;
 191         i = j = 0;
 192         for (k = 0; k < len; k++) {
 193                 i = (i + 1) & 0xff;
 194                 j = (j + s[i]) & 0xff;
 195                 swap(i, j);
 196                 buf[k] ^= s[(s[i] + s[j]) & 0xff];
 197                 crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8);
 198         }
 199         crc = ~crc;
 200
 201         /* now let's check the crc */
 202         c_crc[0] = crc;
 203         c_crc[1] = crc >> 8;
 204         c_crc[2] = crc >> 16;
 205         c_crc[3] = crc >> 24;
 206
 207         for (k = 0; k < 4; k++) {
 208                 i = (i + 1) & 0xff;
 209                 j = (j + s[i]) & 0xff;
 210                 swap(i, j);
 211                 if ((c_crc[k] ^ s[(s[i] + s[j]) & 0xff]) != icv[k])
 212                         return -(4 | (k << 4)); /* ICV mismatch */
 213         }
 214
 215         return 0;
 216 }
 217
 218 /* encrypts in-place. */
 219 int wep_encrypt(wlandevice_t *wlandev, u8 *buf, u8 *dst, u32 len, int keynum,
 220                 u8 *iv, u8 *icv)
 221 {
 222         u32 i, j, k, crc, keylen;
 223         u8 s[256], key[64];
 224
 225         /* no point in WEPping an empty frame */
 226         if (len <= 0)
 227                 return -1;
 228
 229         /* we need to have a real key.. */
 230         if (keynum >= NUM_WEPKEYS)
 231                 return -2;
 232         keylen = wlandev->wep_keylens[keynum];
 233         if (keylen <= 0)
 234                 return -3;
 235
 236         /* use a random IV.  And skip known weak ones. */
 237         get_random_bytes(iv, 3);
 238         while ((iv[1] == 0xff) && (iv[0] >= 3) && (iv[0] < keylen))
 239                 get_random_bytes(iv, 3);
 240
 241         iv[3] = (keynum & 0x03) << 6;
 242
 243         key[0] = iv[0];
 244         key[1] = iv[1];
 245         key[2] = iv[2];
 246
 247         /* copy the rest of the key over from the designated key */
 248         memcpy(key + 3, wlandev->wep_keys[keynum], keylen);
 249
 250         keylen += 3;            /* add in IV bytes */
 251
 252         /* set up the RC4 state */
 253         for (i = 0; i < 256; i++)
 254                 s[i] = i;
 255         j = 0;
 256         for (i = 0; i < 256; i++) {
 257                 j = (j + s[i] + key[i % keylen]) & 0xff;
 258                 swap(i, j);
 259         }
 260
 261         /* Update CRC32 then apply RC4 to the data */
 262         crc = ~0;
 263         i = j = 0;
 264         for (k = 0; k < len; k++) {
 265                 crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8);
 266                 i = (i + 1) & 0xff;
 267                 j = (j + s[i]) & 0xff;
 268                 swap(i, j);
 269                 dst[k] = buf[k] ^ s[(s[i] + s[j]) & 0xff];
 270         }
 271         crc = ~crc;
 272
 273         /* now let's encrypt the crc */
 274         icv[0] = crc;
 275         icv[1] = crc >> 8;
 276         icv[2] = crc >> 16;
 277         icv[3] = crc >> 24;
 278
 279         for (k = 0; k < 4; k++) {
 280                 i = (i + 1) & 0xff;
 281                 j = (j + s[i]) & 0xff;
 282                 swap(i, j);
 283                 icv[k] ^= s[(s[i] + s[j]) & 0xff];
 284         }
 285
 286         return 0;
 287 }