1 /*- 2 * Copyright (c) 2002-2008 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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 /* 30 * IEEE 802.11i AES-CCMP crypto support. 31 * 32 * Part of this module is derived from similar code in the Host 33 * AP driver. The code is used with the consent of the author and 34 * it's license is included below. 35 */ 36 #include "opt_wlan.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/mbuf.h> 41 #include <sys/malloc.h> 42 #include <sys/kernel.h> 43 #include <sys/module.h> 44 45 #include <sys/socket.h> 46 47 #include <net/if.h> 48 #include <net/if_var.h> 49 #include <net/if_media.h> 50 #include <net/ethernet.h> 51 52 #include <netproto/802_11/ieee80211_var.h> 53 54 #include <crypto/rijndael/rijndael.h> 55 56 #define AES_BLOCK_LEN 16 57 58 struct ccmp_ctx { 59 struct ieee80211vap *cc_vap; /* for diagnostics+statistics */ 60 struct ieee80211com *cc_ic; 61 rijndael_ctx cc_aes; 62 }; 63 64 static void *ccmp_attach(struct ieee80211vap *, struct ieee80211_key *); 65 static void ccmp_detach(struct ieee80211_key *); 66 static int ccmp_setkey(struct ieee80211_key *); 67 static void ccmp_setiv(struct ieee80211_key *, uint8_t *); 68 static int ccmp_encap(struct ieee80211_key *, struct mbuf *); 69 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); 70 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); 71 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); 72 73 static const struct ieee80211_cipher ccmp = { 74 .ic_name = "AES-CCM", 75 .ic_cipher = IEEE80211_CIPHER_AES_CCM, 76 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + 77 IEEE80211_WEP_EXTIVLEN, 78 .ic_trailer = IEEE80211_WEP_MICLEN, 79 .ic_miclen = 0, 80 .ic_attach = ccmp_attach, 81 .ic_detach = ccmp_detach, 82 .ic_setkey = ccmp_setkey, 83 .ic_setiv = ccmp_setiv, 84 .ic_encap = ccmp_encap, 85 .ic_decap = ccmp_decap, 86 .ic_enmic = ccmp_enmic, 87 .ic_demic = ccmp_demic, 88 }; 89 90 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 91 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, 92 struct mbuf *, int hdrlen); 93 94 /* number of references from net80211 layer */ 95 static int nrefs = 0; 96 97 static void * 98 ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k) 99 { 100 struct ccmp_ctx *ctx; 101 102 #if defined(__DragonFly__) 103 ctx = (struct ccmp_ctx *) kmalloc(sizeof(struct ccmp_ctx), 104 M_80211_CRYPTO, M_INTWAIT | M_ZERO); 105 #else 106 ctx = (struct ccmp_ctx *) IEEE80211_MALLOC(sizeof(struct ccmp_ctx), 107 M_80211_CRYPTO, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 108 #endif 109 if (ctx == NULL) { 110 vap->iv_stats.is_crypto_nomem++; 111 return NULL; 112 } 113 ctx->cc_vap = vap; 114 ctx->cc_ic = vap->iv_ic; 115 nrefs++; /* NB: we assume caller locking */ 116 return ctx; 117 } 118 119 static void 120 ccmp_detach(struct ieee80211_key *k) 121 { 122 struct ccmp_ctx *ctx = k->wk_private; 123 124 IEEE80211_FREE(ctx, M_80211_CRYPTO); 125 KASSERT(nrefs > 0, ("imbalanced attach/detach")); 126 nrefs--; /* NB: we assume caller locking */ 127 } 128 129 static int 130 ccmp_setkey(struct ieee80211_key *k) 131 { 132 struct ccmp_ctx *ctx = k->wk_private; 133 134 if (k->wk_keylen != (128/NBBY)) { 135 IEEE80211_DPRINTF(ctx->cc_vap, IEEE80211_MSG_CRYPTO, 136 "%s: Invalid key length %u, expecting %u\n", 137 __func__, k->wk_keylen, 128/NBBY); 138 return 0; 139 } 140 if (k->wk_flags & IEEE80211_KEY_SWENCRYPT) 141 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY); 142 return 1; 143 } 144 145 static void 146 ccmp_setiv(struct ieee80211_key *k, uint8_t *ivp) 147 { 148 struct ccmp_ctx *ctx = k->wk_private; 149 struct ieee80211vap *vap = ctx->cc_vap; 150 uint8_t keyid; 151 152 keyid = ieee80211_crypto_get_keyid(vap, k) << 6; 153 154 k->wk_keytsc++; 155 ivp[0] = k->wk_keytsc >> 0; /* PN0 */ 156 ivp[1] = k->wk_keytsc >> 8; /* PN1 */ 157 ivp[2] = 0; /* Reserved */ 158 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ 159 ivp[4] = k->wk_keytsc >> 16; /* PN2 */ 160 ivp[5] = k->wk_keytsc >> 24; /* PN3 */ 161 ivp[6] = k->wk_keytsc >> 32; /* PN4 */ 162 ivp[7] = k->wk_keytsc >> 40; /* PN5 */ 163 } 164 165 /* 166 * Add privacy headers appropriate for the specified key. 167 */ 168 static int 169 ccmp_encap(struct ieee80211_key *k, struct mbuf *m) 170 { 171 struct ccmp_ctx *ctx = k->wk_private; 172 struct ieee80211com *ic = ctx->cc_ic; 173 uint8_t *ivp; 174 int hdrlen; 175 176 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 177 178 /* 179 * Copy down 802.11 header and add the IV, KeyID, and ExtIV. 180 */ 181 M_PREPEND(m, ccmp.ic_header, M_NOWAIT); 182 if (m == NULL) 183 return 0; 184 ivp = mtod(m, uint8_t *); 185 bcopy(ivp + ccmp.ic_header, ivp, hdrlen); 186 ivp += hdrlen; 187 188 ccmp_setiv(k, ivp); 189 190 /* 191 * Finally, do software encrypt if needed. 192 */ 193 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) && 194 !ccmp_encrypt(k, m, hdrlen)) 195 return 0; 196 197 return 1; 198 } 199 200 /* 201 * Add MIC to the frame as needed. 202 */ 203 static int 204 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force) 205 { 206 207 return 1; 208 } 209 210 static __inline uint64_t 211 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) 212 { 213 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); 214 uint16_t iv16 = (b4 << 0) | (b5 << 8); 215 return (((uint64_t)iv16) << 32) | iv32; 216 } 217 218 /* 219 * Validate and strip privacy headers (and trailer) for a 220 * received frame. The specified key should be correct but 221 * is also verified. 222 */ 223 static int 224 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 225 { 226 struct ccmp_ctx *ctx = k->wk_private; 227 struct ieee80211vap *vap = ctx->cc_vap; 228 struct ieee80211_frame *wh; 229 uint8_t *ivp, tid; 230 uint64_t pn; 231 232 /* 233 * Header should have extended IV and sequence number; 234 * verify the former and validate the latter. 235 */ 236 wh = mtod(m, struct ieee80211_frame *); 237 ivp = mtod(m, uint8_t *) + hdrlen; 238 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 239 /* 240 * No extended IV; discard frame. 241 */ 242 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 243 "%s", "missing ExtIV for AES-CCM cipher"); 244 vap->iv_stats.is_rx_ccmpformat++; 245 return 0; 246 } 247 tid = ieee80211_gettid(wh); 248 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 249 if (pn <= k->wk_keyrsc[tid] && 250 (k->wk_flags & IEEE80211_KEY_NOREPLAY) == 0) { 251 /* 252 * Replay violation. 253 */ 254 ieee80211_notify_replay_failure(vap, wh, k, pn, tid); 255 vap->iv_stats.is_rx_ccmpreplay++; 256 return 0; 257 } 258 259 /* 260 * Check if the device handled the decrypt in hardware. 261 * If so we just strip the header; otherwise we need to 262 * handle the decrypt in software. Note that for the 263 * latter we leave the header in place for use in the 264 * decryption work. 265 */ 266 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) && 267 !ccmp_decrypt(k, pn, m, hdrlen)) 268 return 0; 269 270 /* 271 * Copy up 802.11 header and strip crypto bits. 272 */ 273 bcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, hdrlen); 274 m_adj(m, ccmp.ic_header); 275 m_adj(m, -ccmp.ic_trailer); 276 277 /* 278 * Ok to update rsc now. 279 */ 280 k->wk_keyrsc[tid] = pn; 281 282 return 1; 283 } 284 285 /* 286 * Verify and strip MIC from the frame. 287 */ 288 static int 289 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force) 290 { 291 return 1; 292 } 293 294 static __inline void 295 xor_block(uint8_t *b, const uint8_t *a, size_t len) 296 { 297 int i; 298 for (i = 0; i < len; i++) 299 b[i] ^= a[i]; 300 } 301 302 /* 303 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 304 * 305 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> 306 * 307 * This program is free software; you can redistribute it and/or modify 308 * it under the terms of the GNU General Public License version 2 as 309 * published by the Free Software Foundation. See README and COPYING for 310 * more details. 311 * 312 * Alternatively, this software may be distributed under the terms of BSD 313 * license. 314 */ 315 316 static void 317 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, 318 u_int64_t pn, size_t dlen, 319 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], 320 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) 321 { 322 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh) 323 324 /* CCM Initial Block: 325 * Flag (Include authentication header, M=3 (8-octet MIC), 326 * L=1 (2-octet Dlen)) 327 * Nonce: 0x00 | A2 | PN 328 * Dlen */ 329 b0[0] = 0x59; 330 /* NB: b0[1] set below */ 331 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); 332 b0[8] = pn >> 40; 333 b0[9] = pn >> 32; 334 b0[10] = pn >> 24; 335 b0[11] = pn >> 16; 336 b0[12] = pn >> 8; 337 b0[13] = pn >> 0; 338 b0[14] = (dlen >> 8) & 0xff; 339 b0[15] = dlen & 0xff; 340 341 /* AAD: 342 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one 343 * A1 | A2 | A3 344 * SC with bits 4..15 (seq#) masked to zero 345 * A4 (if present) 346 * QC (if present) 347 */ 348 aad[0] = 0; /* AAD length >> 8 */ 349 /* NB: aad[1] set below */ 350 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ 351 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ 352 /* NB: we know 3 addresses are contiguous */ 353 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); 354 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; 355 aad[23] = 0; /* all bits masked */ 356 /* 357 * Construct variable-length portion of AAD based 358 * on whether this is a 4-address frame/QOS frame. 359 * We always zero-pad to 32 bytes before running it 360 * through the cipher. 361 * 362 * We also fill in the priority bits of the CCM 363 * initial block as we know whether or not we have 364 * a QOS frame. 365 */ 366 if (IEEE80211_IS_DSTODS(wh)) { 367 IEEE80211_ADDR_COPY(aad + 24, 368 ((struct ieee80211_frame_addr4 *)wh)->i_addr4); 369 if (IS_QOS_DATA(wh)) { 370 struct ieee80211_qosframe_addr4 *qwh4 = 371 (struct ieee80211_qosframe_addr4 *) wh; 372 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ 373 aad[31] = 0; 374 b0[1] = aad[30]; 375 aad[1] = 22 + IEEE80211_ADDR_LEN + 2; 376 } else { 377 *(uint16_t *)&aad[30] = 0; 378 b0[1] = 0; 379 aad[1] = 22 + IEEE80211_ADDR_LEN; 380 } 381 } else { 382 if (IS_QOS_DATA(wh)) { 383 struct ieee80211_qosframe *qwh = 384 (struct ieee80211_qosframe*) wh; 385 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ 386 aad[25] = 0; 387 b0[1] = aad[24]; 388 aad[1] = 22 + 2; 389 } else { 390 *(uint16_t *)&aad[24] = 0; 391 b0[1] = 0; 392 aad[1] = 22; 393 } 394 *(uint16_t *)&aad[26] = 0; 395 *(uint32_t *)&aad[28] = 0; 396 } 397 398 /* Start with the first block and AAD */ 399 rijndael_encrypt(ctx, b0, auth); 400 xor_block(auth, aad, AES_BLOCK_LEN); 401 rijndael_encrypt(ctx, auth, auth); 402 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 403 rijndael_encrypt(ctx, auth, auth); 404 b0[0] &= 0x07; 405 b0[14] = b0[15] = 0; 406 rijndael_encrypt(ctx, b0, s0); 407 #undef IS_QOS_DATA 408 } 409 410 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ 411 /* Authentication */ \ 412 xor_block(_b, _pos, _len); \ 413 rijndael_encrypt(&ctx->cc_aes, _b, _b); \ 414 /* Encryption, with counter */ \ 415 _b0[14] = (_i >> 8) & 0xff; \ 416 _b0[15] = _i & 0xff; \ 417 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ 418 xor_block(_pos, _e, _len); \ 419 } while (0) 420 421 static int 422 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 423 { 424 struct ccmp_ctx *ctx = key->wk_private; 425 struct ieee80211_frame *wh; 426 struct mbuf *m = m0; 427 int data_len, i, space; 428 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], 429 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; 430 uint8_t *pos; 431 432 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 433 434 wh = mtod(m, struct ieee80211_frame *); 435 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); 436 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, 437 data_len, b0, aad, b, s0); 438 439 i = 1; 440 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 441 /* NB: assumes header is entirely in first mbuf */ 442 space = m->m_len - (hdrlen + ccmp.ic_header); 443 for (;;) { 444 if (space > data_len) 445 space = data_len; 446 /* 447 * Do full blocks. 448 */ 449 while (space >= AES_BLOCK_LEN) { 450 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); 451 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 452 data_len -= AES_BLOCK_LEN; 453 i++; 454 } 455 if (data_len <= 0) /* no more data */ 456 break; 457 m = m->m_next; 458 if (m == NULL) { /* last buffer */ 459 if (space != 0) { 460 /* 461 * Short last block. 462 */ 463 CCMP_ENCRYPT(i, b, b0, pos, e, space); 464 } 465 break; 466 } 467 if (space != 0) { 468 uint8_t *pos_next; 469 int space_next; 470 int len, dl, sp; 471 struct mbuf *n; 472 473 /* 474 * Block straddles one or more mbufs, gather data 475 * into the block buffer b, apply the cipher, then 476 * scatter the results back into the mbuf chain. 477 * The buffer will automatically get space bytes 478 * of data at offset 0 copied in+out by the 479 * CCMP_ENCRYPT request so we must take care of 480 * the remaining data. 481 */ 482 n = m; 483 dl = data_len; 484 sp = space; 485 for (;;) { 486 pos_next = mtod(n, uint8_t *); 487 len = min(dl, AES_BLOCK_LEN); 488 space_next = len > sp ? len - sp : 0; 489 if (n->m_len >= space_next) { 490 /* 491 * This mbuf has enough data; just grab 492 * what we need and stop. 493 */ 494 xor_block(b+sp, pos_next, space_next); 495 break; 496 } 497 /* 498 * This mbuf's contents are insufficient, 499 * take 'em all and prepare to advance to 500 * the next mbuf. 501 */ 502 xor_block(b+sp, pos_next, n->m_len); 503 sp += n->m_len, dl -= n->m_len; 504 n = n->m_next; 505 if (n == NULL) 506 break; 507 } 508 509 CCMP_ENCRYPT(i, b, b0, pos, e, space); 510 511 /* NB: just like above, but scatter data to mbufs */ 512 dl = data_len; 513 sp = space; 514 for (;;) { 515 pos_next = mtod(m, uint8_t *); 516 len = min(dl, AES_BLOCK_LEN); 517 space_next = len > sp ? len - sp : 0; 518 if (m->m_len >= space_next) { 519 xor_block(pos_next, e+sp, space_next); 520 break; 521 } 522 xor_block(pos_next, e+sp, m->m_len); 523 sp += m->m_len, dl -= m->m_len; 524 m = m->m_next; 525 if (m == NULL) 526 goto done; 527 } 528 /* 529 * Do bookkeeping. m now points to the last mbuf 530 * we grabbed data from. We know we consumed a 531 * full block of data as otherwise we'd have hit 532 * the end of the mbuf chain, so deduct from data_len. 533 * Otherwise advance the block number (i) and setup 534 * pos+space to reflect contents of the new mbuf. 535 */ 536 data_len -= AES_BLOCK_LEN; 537 i++; 538 pos = pos_next + space_next; 539 space = m->m_len - space_next; 540 } else { 541 /* 542 * Setup for next buffer. 543 */ 544 pos = mtod(m, uint8_t *); 545 space = m->m_len; 546 } 547 } 548 done: 549 /* tack on MIC */ 550 xor_block(b, s0, ccmp.ic_trailer); 551 return m_append(m0, ccmp.ic_trailer, b); 552 } 553 #undef CCMP_ENCRYPT 554 555 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ 556 /* Decrypt, with counter */ \ 557 _b0[14] = (_i >> 8) & 0xff; \ 558 _b0[15] = _i & 0xff; \ 559 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ 560 xor_block(_pos, _b, _len); \ 561 /* Authentication */ \ 562 xor_block(_a, _pos, _len); \ 563 rijndael_encrypt(&ctx->cc_aes, _a, _a); \ 564 } while (0) 565 566 static int 567 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen) 568 { 569 struct ccmp_ctx *ctx = key->wk_private; 570 struct ieee80211vap *vap = ctx->cc_vap; 571 struct ieee80211_frame *wh; 572 uint8_t aad[2 * AES_BLOCK_LEN]; 573 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; 574 uint8_t mic[AES_BLOCK_LEN]; 575 size_t data_len; 576 int i; 577 uint8_t *pos; 578 u_int space; 579 580 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 581 582 wh = mtod(m, struct ieee80211_frame *); 583 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer); 584 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b); 585 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic); 586 xor_block(mic, b, ccmp.ic_trailer); 587 588 i = 1; 589 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 590 space = m->m_len - (hdrlen + ccmp.ic_header); 591 for (;;) { 592 if (space > data_len) 593 space = data_len; 594 while (space >= AES_BLOCK_LEN) { 595 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); 596 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 597 data_len -= AES_BLOCK_LEN; 598 i++; 599 } 600 if (data_len <= 0) /* no more data */ 601 break; 602 m = m->m_next; 603 if (m == NULL) { /* last buffer */ 604 if (space != 0) /* short last block */ 605 CCMP_DECRYPT(i, b, b0, pos, a, space); 606 break; 607 } 608 if (space != 0) { 609 uint8_t *pos_next; 610 u_int space_next; 611 u_int len; 612 613 /* 614 * Block straddles buffers, split references. We 615 * do not handle splits that require >2 buffers 616 * since rx'd frames are never badly fragmented 617 * because drivers typically recv in clusters. 618 */ 619 pos_next = mtod(m, uint8_t *); 620 len = min(data_len, AES_BLOCK_LEN); 621 space_next = len > space ? len - space : 0; 622 KASSERT(m->m_len >= space_next, 623 ("not enough data in following buffer, " 624 "m_len %u need %u\n", m->m_len, space_next)); 625 626 xor_block(b+space, pos_next, space_next); 627 CCMP_DECRYPT(i, b, b0, pos, a, space); 628 xor_block(pos_next, b+space, space_next); 629 data_len -= len; 630 i++; 631 632 pos = pos_next + space_next; 633 space = m->m_len - space_next; 634 } else { 635 /* 636 * Setup for next buffer. 637 */ 638 pos = mtod(m, uint8_t *); 639 space = m->m_len; 640 } 641 } 642 if (memcmp(mic, a, ccmp.ic_trailer) != 0) { 643 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 644 "%s", "AES-CCM decrypt failed; MIC mismatch"); 645 vap->iv_stats.is_rx_ccmpmic++; 646 return 0; 647 } 648 return 1; 649 } 650 #undef CCMP_DECRYPT 651 652 /* 653 * Module glue. 654 */ 655 IEEE80211_CRYPTO_MODULE(ccmp, 1); 656