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/* #define WEP_DEBUG */ 57 58#include "p80211hdr.h" 59#include "p80211types.h" 60#include "p80211msg.h" 61#include "p80211conv.h" 62#include "p80211netdev.h" 63 64#define WEP_KEY(x) (((x) & 0xC0) >> 6) 65 66static const u32 wep_crc32_table[256] = { 67 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, 68 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L, 69 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 70 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, 71 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L, 72 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, 73 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 74 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL, 75 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L, 76 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL, 77 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 78 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L, 79 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L, 80 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL, 81 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, 82 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L, 83 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL, 84 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L, 85 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, 86 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L, 87 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL, 88 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L, 89 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L, 90 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL, 91 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L, 92 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L, 93 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L, 94 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L, 95 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L, 96 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL, 97 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, 98 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L, 99 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L, 100 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL, 101 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL, 102 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L, 103 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL, 104 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L, 105 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, 106 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L, 107 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL, 108 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L, 109 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, 110 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL, 111 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L, 112 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L, 113 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, 114 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L, 115 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L, 116 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L, 117 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 118 0x2d02ef8dL 119}; 120 121/* keylen in bytes! */ 122 123int wep_change_key(wlandevice_t *wlandev, int keynum, u8 *key, int keylen) 124{ 125 if (keylen < 0) 126 return -1; 127 if (keylen >= MAX_KEYLEN) 128 return -1; 129 if (key == NULL) 130 return -1; 131 if (keynum < 0) 132 return -1; 133 if (keynum >= NUM_WEPKEYS) 134 return -1; 135 136#ifdef WEP_DEBUG 137 printk(KERN_DEBUG 138 "WEP key %d len %d = %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n", 139 keynum, keylen, key[0], key[1], key[2], key[3], key[4], key[5], 140 key[6], key[7]); 141#endif 142 143 wlandev->wep_keylens[keynum] = keylen; 144 memcpy(wlandev->wep_keys[keynum], key, keylen); 145 146 return 0; 147} 148 149/* 150 4-byte IV at start of buffer, 4-byte ICV at end of buffer. 151 if successful, buf start is payload begin, length -= 8; 152 */ 153int wep_decrypt(wlandevice_t *wlandev, u8 *buf, u32 len, int key_override, 154 u8 *iv, u8 *icv) 155{ 156 u32 i, j, k, crc, keylen; 157 u8 s[256], key[64], c_crc[4]; 158 u8 keyidx; 159 160 /* Needs to be at least 8 bytes of payload */ 161 if (len <= 0) 162 return -1; 163 164 /* initialize the first bytes of the key from the IV */ 165 key[0] = iv[0]; 166 key[1] = iv[1]; 167 key[2] = iv[2]; 168 keyidx = WEP_KEY(iv[3]); 169 170 if (key_override >= 0) 171 keyidx = key_override; 172 173 if (keyidx >= NUM_WEPKEYS) 174 return -2; 175 176 keylen = wlandev->wep_keylens[keyidx]; 177 178 if (keylen == 0) 179 return -3; 180 181 /* copy the rest of the key over from the designated key */ 182 memcpy(key + 3, wlandev->wep_keys[keyidx], keylen); 183 184 keylen += 3; /* add in IV bytes */ 185 186#ifdef WEP_DEBUG 187 printk(KERN_DEBUG 188 "D %d: %02x %02x %02x (%d %d) %02x:%02x:%02x:%02x:%02x\n", len, 189 key[0], key[1], key[2], keyidx, keylen, key[3], key[4], key[5], 190 key[6], key[7]); 191#endif 192 193 /* set up the RC4 state */ 194 for (i = 0; i < 256; i++) 195 s[i] = i; 196 j = 0; 197 for (i = 0; i < 256; i++) { 198 j = (j + s[i] + key[i % keylen]) & 0xff; 199 swap(i, j); 200 } 201 202 /* Apply the RC4 to the data, update the CRC32 */ 203 crc = ~0; 204 i = j = 0; 205 for (k = 0; k < len; k++) { 206 i = (i + 1) & 0xff; 207 j = (j + s[i]) & 0xff; 208 swap(i, j); 209 buf[k] ^= s[(s[i] + s[j]) & 0xff]; 210 crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8); 211 } 212 crc = ~crc; 213 214 /* now let's check the crc */ 215 c_crc[0] = crc; 216 c_crc[1] = crc >> 8; 217 c_crc[2] = crc >> 16; 218 c_crc[3] = crc >> 24; 219 220 for (k = 0; k < 4; k++) { 221 i = (i + 1) & 0xff; 222 j = (j + s[i]) & 0xff; 223 swap(i, j); 224 if ((c_crc[k] ^ s[(s[i] + s[j]) & 0xff]) != icv[k]) 225 return -(4 | (k << 4)); /* ICV mismatch */ 226 } 227 228 return 0; 229} 230 231/* encrypts in-place. */ 232int wep_encrypt(wlandevice_t *wlandev, u8 *buf, u8 *dst, u32 len, int keynum, 233 u8 *iv, u8 *icv) 234{ 235 u32 i, j, k, crc, keylen; 236 u8 s[256], key[64]; 237 238 /* no point in WEPping an empty frame */ 239 if (len <= 0) 240 return -1; 241 242 /* we need to have a real key.. */ 243 if (keynum >= NUM_WEPKEYS) 244 return -2; 245 keylen = wlandev->wep_keylens[keynum]; 246 if (keylen <= 0) 247 return -3; 248 249 /* use a random IV. And skip known weak ones. */ 250 get_random_bytes(iv, 3); 251 while ((iv[1] == 0xff) && (iv[0] >= 3) && (iv[0] < keylen)) 252 get_random_bytes(iv, 3); 253 254 iv[3] = (keynum & 0x03) << 6; 255 256 key[0] = iv[0]; 257 key[1] = iv[1]; 258 key[2] = iv[2]; 259 260 /* copy the rest of the key over from the designated key */ 261 memcpy(key + 3, wlandev->wep_keys[keynum], keylen); 262 263 keylen += 3; /* add in IV bytes */ 264 265#ifdef WEP_DEBUG 266 printk(KERN_DEBUG 267 "E %d (%d/%d %d) %02x %02x %02x %02x:%02x:%02x:%02x:%02x\n", len, 268 iv[3], keynum, keylen, key[0], key[1], key[2], key[3], key[4], 269 key[5], key[6], key[7]); 270#endif 271 272 /* set up the RC4 state */ 273 for (i = 0; i < 256; i++) 274 s[i] = i; 275 j = 0; 276 for (i = 0; i < 256; i++) { 277 j = (j + s[i] + key[i % keylen]) & 0xff; 278 swap(i, j); 279 } 280 281 /* Update CRC32 then apply RC4 to the data */ 282 crc = ~0; 283 i = j = 0; 284 for (k = 0; k < len; k++) { 285 crc = wep_crc32_table[(crc ^ buf[k]) & 0xff] ^ (crc >> 8); 286 i = (i + 1) & 0xff; 287 j = (j + s[i]) & 0xff; 288 swap(i, j); 289 dst[k] = buf[k] ^ s[(s[i] + s[j]) & 0xff]; 290 } 291 crc = ~crc; 292 293 /* now let's encrypt the crc */ 294 icv[0] = crc; 295 icv[1] = crc >> 8; 296 icv[2] = crc >> 16; 297 icv[3] = crc >> 24; 298 299 for (k = 0; k < 4; k++) { 300 i = (i + 1) & 0xff; 301 j = (j + s[i]) & 0xff; 302 swap(i, j); 303 icv[k] ^= s[(s[i] + s[j]) & 0xff]; 304 } 305 306 return 0; 307} 308