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sys/net80211/ieee80211_crypto_wep.c
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1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD: releng/12.0/sys/net80211/ieee80211_crypto_wep.c 326272 2017-11-27 15:23:17Z pfg $"); 30 31 /* 32 * IEEE 802.11 WEP crypto support. 33 */ 34 #include "opt_wlan.h" 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/mbuf.h> 39 #include <sys/malloc.h> 40 #include <sys/kernel.h> 41 #include <sys/module.h> 42 #include <sys/endian.h> 43 44 #include <sys/socket.h> 45 46 #include <net/if.h> 47 #include <net/if_media.h> 48 #include <net/ethernet.h> 49 50 #include <net80211/ieee80211_var.h> 51 52 static void *wep_attach(struct ieee80211vap *, struct ieee80211_key *); 53 static void wep_detach(struct ieee80211_key *); 54 static int wep_setkey(struct ieee80211_key *); 55 static void wep_setiv(struct ieee80211_key *, uint8_t *); 56 static int wep_encap(struct ieee80211_key *, struct mbuf *); 57 static int wep_decap(struct ieee80211_key *, struct mbuf *, int); 58 static int wep_enmic(struct ieee80211_key *, struct mbuf *, int); 59 static int wep_demic(struct ieee80211_key *, struct mbuf *, int); 60 61 static const struct ieee80211_cipher wep = { 62 .ic_name = "WEP", 63 .ic_cipher = IEEE80211_CIPHER_WEP, 64 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN, 65 .ic_trailer = IEEE80211_WEP_CRCLEN, 66 .ic_miclen = 0, 67 .ic_attach = wep_attach, 68 .ic_detach = wep_detach, 69 .ic_setkey = wep_setkey, 70 .ic_setiv = wep_setiv, 71 .ic_encap = wep_encap, 72 .ic_decap = wep_decap, 73 .ic_enmic = wep_enmic, 74 .ic_demic = wep_demic, 75 }; 76 77 static int wep_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 78 static int wep_decrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 79 80 struct wep_ctx { 81 struct ieee80211vap *wc_vap; /* for diagnostics+statistics */ 82 struct ieee80211com *wc_ic; 83 uint32_t wc_iv; /* initial vector for crypto */ 84 }; 85 86 /* number of references from net80211 layer */ 87 static int nrefs = 0; 88 89 static void * 90 wep_attach(struct ieee80211vap *vap, struct ieee80211_key *k) 91 { 92 struct wep_ctx *ctx; 93 94 ctx = (struct wep_ctx *) IEEE80211_MALLOC(sizeof(struct wep_ctx), 95 M_80211_CRYPTO, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 96 if (ctx == NULL) { 97 vap->iv_stats.is_crypto_nomem++; 98 return NULL; 99 } 100 101 ctx->wc_vap = vap; 102 ctx->wc_ic = vap->iv_ic; 103 get_random_bytes(&ctx->wc_iv, sizeof(ctx->wc_iv)); 104 nrefs++; /* NB: we assume caller locking */ 105 return ctx; 106 } 107 108 static void 109 wep_detach(struct ieee80211_key *k) 110 { 111 struct wep_ctx *ctx = k->wk_private; 112 113 IEEE80211_FREE(ctx, M_80211_CRYPTO); 114 KASSERT(nrefs > 0, ("imbalanced attach/detach")); 115 nrefs--; /* NB: we assume caller locking */ 116 } 117 118 static int 119 wep_setkey(struct ieee80211_key *k) 120 { 121 return k->wk_keylen >= 40/NBBY; 122 } 123 124 static void 125 wep_setiv(struct ieee80211_key *k, uint8_t *ivp) 126 { 127 struct wep_ctx *ctx = k->wk_private; 128 struct ieee80211vap *vap = ctx->wc_vap; 129 uint32_t iv; 130 uint8_t keyid; 131 132 keyid = ieee80211_crypto_get_keyid(vap, k) << 6; 133 134 /* 135 * XXX 136 * IV must not duplicate during the lifetime of the key. 137 * But no mechanism to renew keys is defined in IEEE 802.11 138 * for WEP. And the IV may be duplicated at other stations 139 * because the session key itself is shared. So we use a 140 * pseudo random IV for now, though it is not the right way. 141 * 142 * NB: Rather than use a strictly random IV we select a 143 * random one to start and then increment the value for 144 * each frame. This is an explicit tradeoff between 145 * overhead and security. Given the basic insecurity of 146 * WEP this seems worthwhile. 147 */ 148 149 /* 150 * Skip 'bad' IVs from Fluhrer/Mantin/Shamir: 151 * (B, 255, N) with 3 <= B < 16 and 0 <= N <= 255 152 */ 153 iv = ctx->wc_iv; 154 if ((iv & 0xff00) == 0xff00) { 155 int B = (iv & 0xff0000) >> 16; 156 if (3 <= B && B < 16) 157 iv += 0x0100; 158 } 159 ctx->wc_iv = iv + 1; 160 161 /* 162 * NB: Preserve byte order of IV for packet 163 * sniffers; it doesn't matter otherwise. 164 */ 165 #if _BYTE_ORDER == _BIG_ENDIAN 166 ivp[0] = iv >> 0; 167 ivp[1] = iv >> 8; 168 ivp[2] = iv >> 16; 169 #else 170 ivp[2] = iv >> 0; 171 ivp[1] = iv >> 8; 172 ivp[0] = iv >> 16; 173 #endif 174 ivp[3] = keyid; 175 } 176 177 /* 178 * Add privacy headers appropriate for the specified key. 179 */ 180 static int 181 wep_encap(struct ieee80211_key *k, struct mbuf *m) 182 { 183 struct wep_ctx *ctx = k->wk_private; 184 struct ieee80211com *ic = ctx->wc_ic; 185 struct ieee80211_frame *wh; 186 uint8_t *ivp; 187 int hdrlen; 188 int is_mgmt; 189 190 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 191 wh = mtod(m, struct ieee80211_frame *); 192 is_mgmt = IEEE80211_IS_MGMT(wh); 193 194 /* 195 * Check to see if IV is required. 196 */ 197 if (is_mgmt && (k->wk_flags & IEEE80211_KEY_NOIVMGT)) 198 return 1; 199 if ((! is_mgmt) && (k->wk_flags & IEEE80211_KEY_NOIV)) 200 return 1; 201 202 /* 203 * Copy down 802.11 header and add the IV + KeyID. 204 */ 205 M_PREPEND(m, wep.ic_header, M_NOWAIT); 206 if (m == NULL) 207 return 0; 208 ivp = mtod(m, uint8_t *); 209 ovbcopy(ivp + wep.ic_header, ivp, hdrlen); 210 ivp += hdrlen; 211 212 wep_setiv(k, ivp); 213 214 /* 215 * Finally, do software encrypt if needed. 216 */ 217 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) && 218 !wep_encrypt(k, m, hdrlen)) 219 return 0; 220 221 return 1; 222 } 223 224 /* 225 * Add MIC to the frame as needed. 226 */ 227 static int 228 wep_enmic(struct ieee80211_key *k, struct mbuf *m, int force) 229 { 230 231 return 1; 232 } 233 234 /* 235 * Validate and strip privacy headers (and trailer) for a 236 * received frame. If necessary, decrypt the frame using 237 * the specified key. 238 */ 239 static int 240 wep_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 241 { 242 struct wep_ctx *ctx = k->wk_private; 243 struct ieee80211vap *vap = ctx->wc_vap; 244 struct ieee80211_frame *wh; 245 const struct ieee80211_rx_stats *rxs; 246 247 wh = mtod(m, struct ieee80211_frame *); 248 249 rxs = ieee80211_get_rx_params_ptr(m); 250 251 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP)) 252 goto finish; 253 254 /* 255 * Check if the device handled the decrypt in hardware. 256 * If so we just strip the header; otherwise we need to 257 * handle the decrypt in software. 258 */ 259 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) && 260 !wep_decrypt(k, m, hdrlen)) { 261 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 262 "%s", "WEP ICV mismatch on decrypt"); 263 vap->iv_stats.is_rx_wepfail++; 264 return 0; 265 } 266 267 /* 268 * Copy up 802.11 header and strip crypto bits. 269 */ 270 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + wep.ic_header, hdrlen); 271 m_adj(m, wep.ic_header); 272 273 finish: 274 /* XXX TODO: do we have to strip this for offload devices? */ 275 m_adj(m, -wep.ic_trailer); 276 277 return 1; 278 } 279 280 /* 281 * Verify and strip MIC from the frame. 282 */ 283 static int 284 wep_demic(struct ieee80211_key *k, struct mbuf *skb, int force) 285 { 286 return 1; 287 } 288 289 static const uint32_t crc32_table[256] = { 290 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, 291 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L, 292 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 293 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, 294 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L, 295 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, 296 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 297 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL, 298 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L, 299 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL, 300 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 301 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L, 302 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L, 303 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL, 304 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, 305 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L, 306 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL, 307 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L, 308 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, 309 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L, 310 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL, 311 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L, 312 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L, 313 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL, 314 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L, 315 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L, 316 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L, 317 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L, 318 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L, 319 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL, 320 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, 321 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L, 322 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L, 323 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL, 324 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL, 325 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L, 326 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL, 327 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L, 328 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, 329 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L, 330 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL, 331 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L, 332 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, 333 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL, 334 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L, 335 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L, 336 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, 337 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L, 338 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L, 339 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L, 340 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 341 0x2d02ef8dL 342 }; 343 344 static int 345 wep_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 346 { 347 #define S_SWAP(a,b) do { uint8_t t = S[a]; S[a] = S[b]; S[b] = t; } while(0) 348 struct wep_ctx *ctx = key->wk_private; 349 struct ieee80211vap *vap = ctx->wc_vap; 350 struct mbuf *m = m0; 351 uint8_t rc4key[IEEE80211_WEP_IVLEN + IEEE80211_KEYBUF_SIZE]; 352 uint8_t icv[IEEE80211_WEP_CRCLEN]; 353 uint32_t i, j, k, crc; 354 size_t buflen, data_len; 355 uint8_t S[256]; 356 uint8_t *pos; 357 u_int off, keylen; 358 359 vap->iv_stats.is_crypto_wep++; 360 361 /* NB: this assumes the header was pulled up */ 362 memcpy(rc4key, mtod(m, uint8_t *) + hdrlen, IEEE80211_WEP_IVLEN); 363 memcpy(rc4key + IEEE80211_WEP_IVLEN, key->wk_key, key->wk_keylen); 364 365 /* Setup RC4 state */ 366 for (i = 0; i < 256; i++) 367 S[i] = i; 368 j = 0; 369 keylen = key->wk_keylen + IEEE80211_WEP_IVLEN; 370 for (i = 0; i < 256; i++) { 371 j = (j + S[i] + rc4key[i % keylen]) & 0xff; 372 S_SWAP(i, j); 373 } 374 375 off = hdrlen + wep.ic_header; 376 data_len = m->m_pkthdr.len - off; 377 378 /* Compute CRC32 over unencrypted data and apply RC4 to data */ 379 crc = ~0; 380 i = j = 0; 381 pos = mtod(m, uint8_t *) + off; 382 buflen = m->m_len - off; 383 for (;;) { 384 if (buflen > data_len) 385 buflen = data_len; 386 data_len -= buflen; 387 for (k = 0; k < buflen; k++) { 388 crc = crc32_table[(crc ^ *pos) & 0xff] ^ (crc >> 8); 389 i = (i + 1) & 0xff; 390 j = (j + S[i]) & 0xff; 391 S_SWAP(i, j); 392 *pos++ ^= S[(S[i] + S[j]) & 0xff]; 393 } 394 if (m->m_next == NULL) { 395 if (data_len != 0) { /* out of data */ 396 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, 397 ether_sprintf(mtod(m0, 398 struct ieee80211_frame *)->i_addr2), 399 "out of data for WEP (data_len %zu)", 400 data_len); 401 /* XXX stat */ 402 return 0; 403 } 404 break; 405 } 406 m = m->m_next; 407 pos = mtod(m, uint8_t *); 408 buflen = m->m_len; 409 } 410 crc = ~crc; 411 412 /* Append little-endian CRC32 and encrypt it to produce ICV */ 413 icv[0] = crc; 414 icv[1] = crc >> 8; 415 icv[2] = crc >> 16; 416 icv[3] = crc >> 24; 417 for (k = 0; k < IEEE80211_WEP_CRCLEN; k++) { 418 i = (i + 1) & 0xff; 419 j = (j + S[i]) & 0xff; 420 S_SWAP(i, j); 421 icv[k] ^= S[(S[i] + S[j]) & 0xff]; 422 } 423 return m_append(m0, IEEE80211_WEP_CRCLEN, icv); 424 #undef S_SWAP 425 } 426 427 static int 428 wep_decrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 429 { 430 #define S_SWAP(a,b) do { uint8_t t = S[a]; S[a] = S[b]; S[b] = t; } while(0) 431 struct wep_ctx *ctx = key->wk_private; 432 struct ieee80211vap *vap = ctx->wc_vap; 433 struct mbuf *m = m0; 434 uint8_t rc4key[IEEE80211_WEP_IVLEN + IEEE80211_KEYBUF_SIZE]; 435 uint8_t icv[IEEE80211_WEP_CRCLEN]; 436 uint32_t i, j, k, crc; 437 size_t buflen, data_len; 438 uint8_t S[256]; 439 uint8_t *pos; 440 u_int off, keylen; 441 442 vap->iv_stats.is_crypto_wep++; 443 444 /* NB: this assumes the header was pulled up */ 445 memcpy(rc4key, mtod(m, uint8_t *) + hdrlen, IEEE80211_WEP_IVLEN); 446 memcpy(rc4key + IEEE80211_WEP_IVLEN, key->wk_key, key->wk_keylen); 447 448 /* Setup RC4 state */ 449 for (i = 0; i < 256; i++) 450 S[i] = i; 451 j = 0; 452 keylen = key->wk_keylen + IEEE80211_WEP_IVLEN; 453 for (i = 0; i < 256; i++) { 454 j = (j + S[i] + rc4key[i % keylen]) & 0xff; 455 S_SWAP(i, j); 456 } 457 458 off = hdrlen + wep.ic_header; 459 data_len = m->m_pkthdr.len - (off + wep.ic_trailer); 460 461 /* Compute CRC32 over unencrypted data and apply RC4 to data */ 462 crc = ~0; 463 i = j = 0; 464 pos = mtod(m, uint8_t *) + off; 465 buflen = m->m_len - off; 466 for (;;) { 467 if (buflen > data_len) 468 buflen = data_len; 469 data_len -= buflen; 470 for (k = 0; k < buflen; k++) { 471 i = (i + 1) & 0xff; 472 j = (j + S[i]) & 0xff; 473 S_SWAP(i, j); 474 *pos ^= S[(S[i] + S[j]) & 0xff]; 475 crc = crc32_table[(crc ^ *pos) & 0xff] ^ (crc >> 8); 476 pos++; 477 } 478 m = m->m_next; 479 if (m == NULL) { 480 if (data_len != 0) { /* out of data */ 481 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, 482 mtod(m0, struct ieee80211_frame *)->i_addr2, 483 "out of data for WEP (data_len %zu)", 484 data_len); 485 return 0; 486 } 487 break; 488 } 489 pos = mtod(m, uint8_t *); 490 buflen = m->m_len; 491 } 492 crc = ~crc; 493 494 /* Encrypt little-endian CRC32 and verify that it matches with 495 * received ICV */ 496 icv[0] = crc; 497 icv[1] = crc >> 8; 498 icv[2] = crc >> 16; 499 icv[3] = crc >> 24; 500 for (k = 0; k < IEEE80211_WEP_CRCLEN; k++) { 501 i = (i + 1) & 0xff; 502 j = (j + S[i]) & 0xff; 503 S_SWAP(i, j); 504 /* XXX assumes ICV is contiguous in mbuf */ 505 if ((icv[k] ^ S[(S[i] + S[j]) & 0xff]) != *pos++) { 506 /* ICV mismatch - drop frame */ 507 return 0; 508 } 509 } 510 return 1; 511 #undef S_SWAP 512 } 513 514 /* 515 * Module glue. 516 */ 517 IEEE80211_CRYPTO_MODULE(wep, 1);
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