Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/net80211/ieee80211_crypto_ccmp.c
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1 /*- 2 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * Alternatively, this software may be distributed under the terms of the 17 * GNU General Public License ("GPL") version 2 as published by the Free 18 * Software Foundation. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifdef __FreeBSD__ 34 __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto_ccmp.c,v 1.7 2005/07/11 03:06:23 sam Exp $"); 35 #endif 36 #ifdef __NetBSD__ 37 __KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto_ccmp.c,v 1.7 2006/11/16 01:33:40 christos Exp $"); 38 #endif 39 40 /* 41 * IEEE 802.11i AES-CCMP crypto support. 42 * 43 * Part of this module is derived from similar code in the Host 44 * AP driver. The code is used with the consent of the author and 45 * it's license is included below. 46 */ 47 #include <sys/param.h> 48 #include <sys/systm.h> 49 #include <sys/mbuf.h> 50 #include <sys/malloc.h> 51 #include <sys/kernel.h> 52 53 #include <sys/socket.h> 54 55 #include <net/if.h> 56 #include <net/if_ether.h> 57 #include <net/if_media.h> 58 59 #include <net80211/ieee80211_var.h> 60 61 #include <crypto/rijndael/rijndael.h> 62 63 #define AES_BLOCK_LEN 16 64 65 struct ccmp_ctx { 66 struct ieee80211com *cc_ic; /* for diagnostics */ 67 rijndael_ctx cc_aes; 68 }; 69 70 static void *ccmp_attach(struct ieee80211com *, struct ieee80211_key *); 71 static void ccmp_detach(struct ieee80211_key *); 72 static int ccmp_setkey(struct ieee80211_key *); 73 static int ccmp_encap(struct ieee80211_key *k, struct mbuf *, u_int8_t keyid); 74 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); 75 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); 76 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); 77 78 const struct ieee80211_cipher ieee80211_cipher_ccmp = { 79 .ic_name = "AES-CCM", 80 .ic_cipher = IEEE80211_CIPHER_AES_CCM, 81 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + 82 IEEE80211_WEP_EXTIVLEN, 83 .ic_trailer = IEEE80211_WEP_MICLEN, 84 .ic_miclen = 0, 85 .ic_attach = ccmp_attach, 86 .ic_detach = ccmp_detach, 87 .ic_setkey = ccmp_setkey, 88 .ic_encap = ccmp_encap, 89 .ic_decap = ccmp_decap, 90 .ic_enmic = ccmp_enmic, 91 .ic_demic = ccmp_demic, 92 }; 93 94 #define ccmp ieee80211_cipher_ccmp 95 96 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 97 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, 98 struct mbuf *, int hdrlen); 99 100 static void * 101 ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k) 102 { 103 struct ccmp_ctx *ctx; 104 105 MALLOC(ctx, struct ccmp_ctx *, sizeof(struct ccmp_ctx), 106 M_DEVBUF, M_NOWAIT | M_ZERO); 107 if (ctx == NULL) { 108 ic->ic_stats.is_crypto_nomem++; 109 return NULL; 110 } 111 ctx->cc_ic = ic; 112 return ctx; 113 } 114 115 static void 116 ccmp_detach(struct ieee80211_key *k) 117 { 118 struct ccmp_ctx *ctx = k->wk_private; 119 120 FREE(ctx, M_DEVBUF); 121 } 122 123 static int 124 ccmp_setkey(struct ieee80211_key *k) 125 { 126 struct ccmp_ctx *ctx = k->wk_private; 127 128 if (k->wk_keylen != (128/NBBY)) { 129 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 130 "%s: Invalid key length %u, expecting %u\n", 131 __func__, k->wk_keylen, 128/NBBY); 132 return 0; 133 } 134 if (k->wk_flags & IEEE80211_KEY_SWCRYPT) 135 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY); 136 return 1; 137 } 138 139 /* 140 * Add privacy headers appropriate for the specified key. 141 */ 142 static int 143 ccmp_encap(struct ieee80211_key *k, struct mbuf *m, u_int8_t keyid) 144 { 145 struct ccmp_ctx *ctx = k->wk_private; 146 struct ieee80211com *ic = ctx->cc_ic; 147 u_int8_t *ivp; 148 int hdrlen; 149 150 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 151 152 /* 153 * Copy down 802.11 header and add the IV, KeyID, and ExtIV. 154 */ 155 M_PREPEND(m, ccmp.ic_header, M_NOWAIT); 156 if (m == NULL) 157 return 0; 158 ivp = mtod(m, u_int8_t *); 159 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen); 160 ivp += hdrlen; 161 162 k->wk_keytsc++; /* XXX wrap at 48 bits */ 163 ivp[0] = k->wk_keytsc >> 0; /* PN0 */ 164 ivp[1] = k->wk_keytsc >> 8; /* PN1 */ 165 ivp[2] = 0; /* Reserved */ 166 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ 167 ivp[4] = k->wk_keytsc >> 16; /* PN2 */ 168 ivp[5] = k->wk_keytsc >> 24; /* PN3 */ 169 ivp[6] = k->wk_keytsc >> 32; /* PN4 */ 170 ivp[7] = k->wk_keytsc >> 40; /* PN5 */ 171 172 /* 173 * Finally, do software encrypt if neeed. 174 */ 175 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && 176 !ccmp_encrypt(k, m, hdrlen)) 177 return 0; 178 179 return 1; 180 } 181 182 /* 183 * Add MIC to the frame as needed. 184 */ 185 static int 186 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, 187 int force) 188 { 189 190 return 1; 191 } 192 193 static __inline uint64_t 194 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) 195 { 196 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); 197 uint16_t iv16 = (b4 << 0) | (b5 << 8); 198 return (((uint64_t)iv16) << 32) | iv32; 199 } 200 201 /* 202 * Validate and strip privacy headers (and trailer) for a 203 * received frame. The specified key should be correct but 204 * is also verified. 205 */ 206 static int 207 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 208 { 209 struct ccmp_ctx *ctx = k->wk_private; 210 struct ieee80211_frame *wh; 211 uint8_t *ivp; 212 uint64_t pn; 213 214 /* 215 * Header should have extended IV and sequence number; 216 * verify the former and validate the latter. 217 */ 218 wh = mtod(m, struct ieee80211_frame *); 219 ivp = mtod(m, uint8_t *) + hdrlen; 220 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 221 /* 222 * No extended IV; discard frame. 223 */ 224 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 225 "[%s] Missing ExtIV for AES-CCM cipher\n", 226 ether_sprintf(wh->i_addr2)); 227 ctx->cc_ic->ic_stats.is_rx_ccmpformat++; 228 return 0; 229 } 230 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 231 if (pn <= k->wk_keyrsc) { 232 /* 233 * Replay violation. 234 */ 235 ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn); 236 ctx->cc_ic->ic_stats.is_rx_ccmpreplay++; 237 return 0; 238 } 239 240 /* 241 * Check if the device handled the decrypt in hardware. 242 * If so we just strip the header; otherwise we need to 243 * handle the decrypt in software. Note that for the 244 * latter we leave the header in place for use in the 245 * decryption work. 246 */ 247 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && 248 !ccmp_decrypt(k, pn, m, hdrlen)) 249 return 0; 250 251 /* 252 * Copy up 802.11 header and strip crypto bits. 253 */ 254 ovbcopy(mtod(m, void *), mtod(m, u_int8_t *) + ccmp.ic_header, hdrlen); 255 m_adj(m, ccmp.ic_header); 256 m_adj(m, -ccmp.ic_trailer); 257 258 /* 259 * Ok to update rsc now. 260 */ 261 k->wk_keyrsc = pn; 262 263 return 1; 264 } 265 266 /* 267 * Verify and strip MIC from the frame. 268 */ 269 static int 270 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, 271 int force) 272 { 273 return 1; 274 } 275 276 static __inline void 277 xor_block(uint8_t *b, const uint8_t *a, size_t len) 278 { 279 int i; 280 for (i = 0; i < len; i++) 281 b[i] ^= a[i]; 282 } 283 284 /* 285 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 286 * 287 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> 288 * 289 * This program is free software; you can redistribute it and/or modify 290 * it under the terms of the GNU General Public License version 2 as 291 * published by the Free Software Foundation. See README and COPYING for 292 * more details. 293 * 294 * Alternatively, this software may be distributed under the terms of BSD 295 * license. 296 */ 297 298 static void 299 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, 300 u_int64_t pn, size_t dlen, 301 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], 302 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) 303 { 304 #define IS_4ADDRESS(wh) \ 305 ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS) 306 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh) 307 308 /* CCM Initial Block: 309 * Flag (Include authentication header, M=3 (8-octet MIC), 310 * L=1 (2-octet Dlen)) 311 * Nonce: 0x00 | A2 | PN 312 * Dlen */ 313 b0[0] = 0x59; 314 /* NB: b0[1] set below */ 315 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); 316 b0[8] = pn >> 40; 317 b0[9] = pn >> 32; 318 b0[10] = pn >> 24; 319 b0[11] = pn >> 16; 320 b0[12] = pn >> 8; 321 b0[13] = pn >> 0; 322 b0[14] = (dlen >> 8) & 0xff; 323 b0[15] = dlen & 0xff; 324 325 /* AAD: 326 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one 327 * A1 | A2 | A3 328 * SC with bits 4..15 (seq#) masked to zero 329 * A4 (if present) 330 * QC (if present) 331 */ 332 aad[0] = 0; /* AAD length >> 8 */ 333 /* NB: aad[1] set below */ 334 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ 335 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ 336 /* NB: we know 3 addresses are contiguous */ 337 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); 338 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; 339 aad[23] = 0; /* all bits masked */ 340 /* 341 * Construct variable-length portion of AAD based 342 * on whether this is a 4-address frame/QOS frame. 343 * We always zero-pad to 32 bytes before running it 344 * through the cipher. 345 * 346 * We also fill in the priority bits of the CCM 347 * initial block as we know whether or not we have 348 * a QOS frame. 349 */ 350 if (IS_4ADDRESS(wh)) { 351 IEEE80211_ADDR_COPY(aad + 24, 352 ((struct ieee80211_frame_addr4 *)wh)->i_addr4); 353 if (IS_QOS_DATA(wh)) { 354 struct ieee80211_qosframe_addr4 *qwh4 = 355 (struct ieee80211_qosframe_addr4 *) wh; 356 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ 357 aad[31] = 0; 358 b0[1] = aad[30]; 359 aad[1] = 22 + IEEE80211_ADDR_LEN + 2; 360 } else { 361 *(u_int16_t *)&aad[30] = 0; 362 b0[1] = 0; 363 aad[1] = 22 + IEEE80211_ADDR_LEN; 364 } 365 } else { 366 if (IS_QOS_DATA(wh)) { 367 struct ieee80211_qosframe *qwh = 368 (struct ieee80211_qosframe*) wh; 369 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ 370 aad[25] = 0; 371 b0[1] = aad[24]; 372 aad[1] = 22 + 2; 373 } else { 374 *(u_int16_t *)&aad[24] = 0; 375 b0[1] = 0; 376 aad[1] = 22; 377 } 378 *(u_int16_t *)&aad[26] = 0; 379 *(u_int32_t *)&aad[28] = 0; 380 } 381 382 /* Start with the first block and AAD */ 383 rijndael_encrypt(ctx, b0, auth); 384 xor_block(auth, aad, AES_BLOCK_LEN); 385 rijndael_encrypt(ctx, auth, auth); 386 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 387 rijndael_encrypt(ctx, auth, auth); 388 b0[0] &= 0x07; 389 b0[14] = b0[15] = 0; 390 rijndael_encrypt(ctx, b0, s0); 391 #undef IS_QOS_DATA 392 #undef IS_4ADDRESS 393 } 394 395 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ 396 /* Authentication */ \ 397 xor_block(_b, _pos, _len); \ 398 rijndael_encrypt(&ctx->cc_aes, _b, _b); \ 399 /* Encryption, with counter */ \ 400 _b0[14] = (_i >> 8) & 0xff; \ 401 _b0[15] = _i & 0xff; \ 402 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ 403 xor_block(_pos, _e, _len); \ 404 } while (0) 405 406 static int 407 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 408 { 409 struct ccmp_ctx *ctx = key->wk_private; 410 struct ieee80211_frame *wh; 411 struct mbuf *m = m0; 412 int data_len, i, space; 413 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], 414 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; 415 uint8_t *pos; 416 417 ctx->cc_ic->ic_stats.is_crypto_ccmp++; 418 419 wh = mtod(m, struct ieee80211_frame *); 420 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); 421 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, 422 data_len, b0, aad, b, s0); 423 424 i = 1; 425 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 426 /* NB: assumes header is entirely in first mbuf */ 427 space = m->m_len - (hdrlen + ccmp.ic_header); 428 for (;;) { 429 if (space > data_len) 430 space = data_len; 431 /* 432 * Do full blocks. 433 */ 434 while (space >= AES_BLOCK_LEN) { 435 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); 436 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 437 data_len -= AES_BLOCK_LEN; 438 i++; 439 } 440 if (data_len <= 0) /* no more data */ 441 break; 442 m = m->m_next; 443 if (m == NULL) { /* last buffer */ 444 if (space != 0) { 445 /* 446 * Short last block. 447 */ 448 CCMP_ENCRYPT(i, b, b0, pos, e, space); 449 } 450 break; 451 } 452 if (space != 0) { 453 uint8_t *pos_next; 454 int space_next; 455 int len, dl, sp; 456 struct mbuf *n; 457 458 /* 459 * Block straddles one or more mbufs, gather data 460 * into the block buffer b, apply the cipher, then 461 * scatter the results back into the mbuf chain. 462 * The buffer will automatically get space bytes 463 * of data at offset 0 copied in+out by the 464 * CCMP_ENCRYPT request so we must take care of 465 * the remaining data. 466 */ 467 n = m; 468 dl = data_len; 469 sp = space; 470 for (;;) { 471 pos_next = mtod(n, uint8_t *); 472 len = min(dl, AES_BLOCK_LEN); 473 space_next = len > sp ? len - sp : 0; 474 if (n->m_len >= space_next) { 475 /* 476 * This mbuf has enough data; just grab 477 * what we need and stop. 478 */ 479 xor_block(b+sp, pos_next, space_next); 480 break; 481 } 482 /* 483 * This mbuf's contents are insufficient, 484 * take 'em all and prepare to advance to 485 * the next mbuf. 486 */ 487 xor_block(b+sp, pos_next, n->m_len); 488 sp += n->m_len, dl -= n->m_len; 489 n = n->m_next; 490 if (n == NULL) 491 break; 492 } 493 494 CCMP_ENCRYPT(i, b, b0, pos, e, space); 495 496 /* NB: just like above, but scatter data to mbufs */ 497 dl = data_len; 498 sp = space; 499 for (;;) { 500 pos_next = mtod(m, uint8_t *); 501 len = min(dl, AES_BLOCK_LEN); 502 space_next = len > sp ? len - sp : 0; 503 if (m->m_len >= space_next) { 504 xor_block(pos_next, e+sp, space_next); 505 break; 506 } 507 xor_block(pos_next, e+sp, m->m_len); 508 sp += m->m_len, dl -= m->m_len; 509 m = m->m_next; 510 if (m == NULL) 511 goto done; 512 } 513 /* 514 * Do bookkeeping. m now points to the last mbuf 515 * we grabbed data from. We know we consumed a 516 * full block of data as otherwise we'd have hit 517 * the end of the mbuf chain, so deduct from data_len. 518 * Otherwise advance the block number (i) and setup 519 * pos+space to reflect contents of the new mbuf. 520 */ 521 data_len -= AES_BLOCK_LEN; 522 i++; 523 pos = pos_next + space_next; 524 space = m->m_len - space_next; 525 } else { 526 /* 527 * Setup for next buffer. 528 */ 529 pos = mtod(m, uint8_t *); 530 space = m->m_len; 531 } 532 } 533 done: 534 /* tack on MIC */ 535 xor_block(b, s0, ccmp.ic_trailer); 536 return m_append(m0, ccmp.ic_trailer, b); 537 } 538 #undef CCMP_ENCRYPT 539 540 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ 541 /* Decrypt, with counter */ \ 542 _b0[14] = (_i >> 8) & 0xff; \ 543 _b0[15] = _i & 0xff; \ 544 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ 545 xor_block(_pos, _b, _len); \ 546 /* Authentication */ \ 547 xor_block(_a, _pos, _len); \ 548 rijndael_encrypt(&ctx->cc_aes, _a, _a); \ 549 } while (0) 550 551 static int 552 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen) 553 { 554 struct ccmp_ctx *ctx = key->wk_private; 555 struct ieee80211_frame *wh; 556 uint8_t aad[2 * AES_BLOCK_LEN]; 557 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; 558 uint8_t mic[AES_BLOCK_LEN]; 559 size_t data_len; 560 int i; 561 uint8_t *pos; 562 u_int space; 563 564 ctx->cc_ic->ic_stats.is_crypto_ccmp++; 565 566 wh = mtod(m, struct ieee80211_frame *); 567 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer); 568 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b); 569 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic); 570 xor_block(mic, b, ccmp.ic_trailer); 571 572 i = 1; 573 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 574 space = m->m_len - (hdrlen + ccmp.ic_header); 575 for (;;) { 576 if (space > data_len) 577 space = data_len; 578 while (space >= AES_BLOCK_LEN) { 579 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); 580 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 581 data_len -= AES_BLOCK_LEN; 582 i++; 583 } 584 if (data_len <= 0) /* no more data */ 585 break; 586 m = m->m_next; 587 if (m == NULL) { /* last buffer */ 588 if (space != 0) /* short last block */ 589 CCMP_DECRYPT(i, b, b0, pos, a, space); 590 break; 591 } 592 if (space != 0) { 593 uint8_t *pos_next; 594 u_int space_next; 595 u_int len; 596 597 /* 598 * Block straddles buffers, split references. We 599 * do not handle splits that require >2 buffers 600 * since rx'd frames are never badly fragmented 601 * because drivers typically recv in clusters. 602 */ 603 pos_next = mtod(m, uint8_t *); 604 len = min(data_len, AES_BLOCK_LEN); 605 space_next = len > space ? len - space : 0; 606 IASSERT(m->m_len >= space_next, 607 ("not enough data in following buffer, " 608 "m_len %u need %u\n", m->m_len, space_next)); 609 610 xor_block(b+space, pos_next, space_next); 611 CCMP_DECRYPT(i, b, b0, pos, a, space); 612 xor_block(pos_next, b+space, space_next); 613 data_len -= len; 614 i++; 615 616 pos = pos_next + space_next; 617 space = m->m_len - space_next; 618 } else { 619 /* 620 * Setup for next buffer. 621 */ 622 pos = mtod(m, uint8_t *); 623 space = m->m_len; 624 } 625 } 626 if (memcmp(mic, a, ccmp.ic_trailer) != 0) { 627 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 628 "[%s] AES-CCM decrypt failed; MIC mismatch\n", 629 ether_sprintf(wh->i_addr2)); 630 ctx->cc_ic->ic_stats.is_rx_ccmpmic++; 631 return 0; 632 } 633 return 1; 634 } 635 #undef CCMP_DECRYPT 636 637 IEEE80211_CRYPTO_SETUP(ccmp_register) 638 { 639 ieee80211_crypto_register(&ccmp); 640 }
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