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("$FreeBSD$"); 30 31 /* 32 * IEEE 802.11i AES-CCMP crypto support. 33 * 34 * Part of this module is derived from similar code in the Host 35 * AP driver. The code is used with the consent of the author and 36 * it's license is included below. 37 */ 38 #include "opt_wlan.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/mbuf.h> 43 #include <sys/malloc.h> 44 #include <sys/kernel.h> 45 #include <sys/module.h> 46 47 #include <sys/socket.h> 48 49 #include <net/if.h> 50 #include <net/if_media.h> 51 #include <net/ethernet.h> 52 53 #include <net80211/ieee80211_var.h> 54 55 #include <crypto/rijndael/rijndael.h> 56 57 #define AES_BLOCK_LEN 16 58 59 struct ccmp_ctx { 60 struct ieee80211vap *cc_vap; /* for diagnostics+statistics */ 61 struct ieee80211com *cc_ic; 62 rijndael_ctx cc_aes; 63 }; 64 65 static void *ccmp_attach(struct ieee80211vap *, struct ieee80211_key *); 66 static void ccmp_detach(struct ieee80211_key *); 67 static int ccmp_setkey(struct ieee80211_key *); 68 static void ccmp_setiv(struct ieee80211_key *, uint8_t *); 69 static int ccmp_encap(struct ieee80211_key *, struct mbuf *); 70 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); 71 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); 72 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); 73 74 static const struct ieee80211_cipher ccmp = { 75 .ic_name = "AES-CCM", 76 .ic_cipher = IEEE80211_CIPHER_AES_CCM, 77 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + 78 IEEE80211_WEP_EXTIVLEN, 79 .ic_trailer = IEEE80211_WEP_MICLEN, 80 .ic_miclen = 0, 81 .ic_attach = ccmp_attach, 82 .ic_detach = ccmp_detach, 83 .ic_setkey = ccmp_setkey, 84 .ic_setiv = ccmp_setiv, 85 .ic_encap = ccmp_encap, 86 .ic_decap = ccmp_decap, 87 .ic_enmic = ccmp_enmic, 88 .ic_demic = ccmp_demic, 89 }; 90 91 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 92 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, 93 struct mbuf *, int hdrlen); 94 95 /* number of references from net80211 layer */ 96 static int nrefs = 0; 97 98 static void * 99 ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k) 100 { 101 struct ccmp_ctx *ctx; 102 103 ctx = (struct ccmp_ctx *) IEEE80211_MALLOC(sizeof(struct ccmp_ctx), 104 M_80211_CRYPTO, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 105 if (ctx == NULL) { 106 vap->iv_stats.is_crypto_nomem++; 107 return NULL; 108 } 109 ctx->cc_vap = vap; 110 ctx->cc_ic = vap->iv_ic; 111 nrefs++; /* NB: we assume caller locking */ 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 IEEE80211_FREE(ctx, M_80211_CRYPTO); 121 KASSERT(nrefs > 0, ("imbalanced attach/detach")); 122 nrefs--; /* NB: we assume caller locking */ 123 } 124 125 static int 126 ccmp_setkey(struct ieee80211_key *k) 127 { 128 struct ccmp_ctx *ctx = k->wk_private; 129 130 if (k->wk_keylen != (128/NBBY)) { 131 IEEE80211_DPRINTF(ctx->cc_vap, IEEE80211_MSG_CRYPTO, 132 "%s: Invalid key length %u, expecting %u\n", 133 __func__, k->wk_keylen, 128/NBBY); 134 return 0; 135 } 136 if (k->wk_flags & IEEE80211_KEY_SWENCRYPT) 137 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY); 138 return 1; 139 } 140 141 static void 142 ccmp_setiv(struct ieee80211_key *k, uint8_t *ivp) 143 { 144 struct ccmp_ctx *ctx = k->wk_private; 145 struct ieee80211vap *vap = ctx->cc_vap; 146 uint8_t keyid; 147 148 keyid = ieee80211_crypto_get_keyid(vap, k) << 6; 149 150 k->wk_keytsc++; 151 ivp[0] = k->wk_keytsc >> 0; /* PN0 */ 152 ivp[1] = k->wk_keytsc >> 8; /* PN1 */ 153 ivp[2] = 0; /* Reserved */ 154 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ 155 ivp[4] = k->wk_keytsc >> 16; /* PN2 */ 156 ivp[5] = k->wk_keytsc >> 24; /* PN3 */ 157 ivp[6] = k->wk_keytsc >> 32; /* PN4 */ 158 ivp[7] = k->wk_keytsc >> 40; /* PN5 */ 159 } 160 161 /* 162 * Add privacy headers appropriate for the specified key. 163 */ 164 static int 165 ccmp_encap(struct ieee80211_key *k, struct mbuf *m) 166 { 167 const struct ieee80211_frame *wh; 168 struct ccmp_ctx *ctx = k->wk_private; 169 struct ieee80211com *ic = ctx->cc_ic; 170 uint8_t *ivp; 171 int hdrlen; 172 int is_mgmt; 173 174 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 175 wh = mtod(m, const struct ieee80211_frame *); 176 is_mgmt = IEEE80211_IS_MGMT(wh); 177 178 /* 179 * Check to see if we need to insert IV/MIC. 180 * 181 * Some offload devices don't require the IV to be inserted 182 * as part of the hardware encryption. 183 */ 184 if (is_mgmt && (k->wk_flags & IEEE80211_KEY_NOIVMGT)) 185 return 1; 186 if ((! is_mgmt) && (k->wk_flags & IEEE80211_KEY_NOIV)) 187 return 1; 188 189 /* 190 * Copy down 802.11 header and add the IV, KeyID, and ExtIV. 191 */ 192 M_PREPEND(m, ccmp.ic_header, M_NOWAIT); 193 if (m == NULL) 194 return 0; 195 ivp = mtod(m, uint8_t *); 196 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen); 197 ivp += hdrlen; 198 199 ccmp_setiv(k, ivp); 200 201 /* 202 * Finally, do software encrypt if needed. 203 */ 204 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) && 205 !ccmp_encrypt(k, m, hdrlen)) 206 return 0; 207 208 return 1; 209 } 210 211 /* 212 * Add MIC to the frame as needed. 213 */ 214 static int 215 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force) 216 { 217 218 return 1; 219 } 220 221 static __inline uint64_t 222 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) 223 { 224 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); 225 uint16_t iv16 = (b4 << 0) | (b5 << 8); 226 return (((uint64_t)iv16) << 32) | iv32; 227 } 228 229 /* 230 * Validate and strip privacy headers (and trailer) for a 231 * received frame. The specified key should be correct but 232 * is also verified. 233 */ 234 static int 235 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 236 { 237 const struct ieee80211_rx_stats *rxs; 238 struct ccmp_ctx *ctx = k->wk_private; 239 struct ieee80211vap *vap = ctx->cc_vap; 240 struct ieee80211_frame *wh; 241 uint8_t *ivp, tid; 242 uint64_t pn; 243 244 rxs = ieee80211_get_rx_params_ptr(m); 245 246 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP)) 247 goto finish; 248 249 /* 250 * Header should have extended IV and sequence number; 251 * verify the former and validate the latter. 252 */ 253 wh = mtod(m, struct ieee80211_frame *); 254 ivp = mtod(m, uint8_t *) + hdrlen; 255 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 256 /* 257 * No extended IV; discard frame. 258 */ 259 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 260 "%s", "missing ExtIV for AES-CCM cipher"); 261 vap->iv_stats.is_rx_ccmpformat++; 262 return 0; 263 } 264 tid = ieee80211_gettid(wh); 265 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 266 if (pn <= k->wk_keyrsc[tid] && 267 (k->wk_flags & IEEE80211_KEY_NOREPLAY) == 0) { 268 /* 269 * Replay violation. 270 */ 271 ieee80211_notify_replay_failure(vap, wh, k, pn, tid); 272 vap->iv_stats.is_rx_ccmpreplay++; 273 return 0; 274 } 275 276 /* 277 * Check if the device handled the decrypt in hardware. 278 * If so we just strip the header; otherwise we need to 279 * handle the decrypt in software. Note that for the 280 * latter we leave the header in place for use in the 281 * decryption work. 282 */ 283 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) && 284 !ccmp_decrypt(k, pn, m, hdrlen)) 285 return 0; 286 287 finish: 288 /* 289 * Copy up 802.11 header and strip crypto bits. 290 */ 291 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) { 292 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, 293 hdrlen); 294 m_adj(m, ccmp.ic_header); 295 } 296 297 /* 298 * XXX TODO: see if MMIC_STRIP also covers CCMP MIC trailer. 299 */ 300 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP))) 301 m_adj(m, -ccmp.ic_trailer); 302 303 /* 304 * Ok to update rsc now. 305 */ 306 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) { 307 k->wk_keyrsc[tid] = pn; 308 } 309 310 return 1; 311 } 312 313 /* 314 * Verify and strip MIC from the frame. 315 */ 316 static int 317 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force) 318 { 319 return 1; 320 } 321 322 static __inline void 323 xor_block(uint8_t *b, const uint8_t *a, size_t len) 324 { 325 int i; 326 for (i = 0; i < len; i++) 327 b[i] ^= a[i]; 328 } 329 330 /* 331 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 332 * 333 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> 334 * 335 * This program is free software; you can redistribute it and/or modify 336 * it under the terms of the GNU General Public License version 2 as 337 * published by the Free Software Foundation. See README and COPYING for 338 * more details. 339 * 340 * Alternatively, this software may be distributed under the terms of BSD 341 * license. 342 */ 343 344 static void 345 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, 346 u_int64_t pn, size_t dlen, 347 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], 348 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) 349 { 350 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh) 351 352 /* CCM Initial Block: 353 * Flag (Include authentication header, M=3 (8-octet MIC), 354 * L=1 (2-octet Dlen)) 355 * Nonce: 0x00 | A2 | PN 356 * Dlen */ 357 b0[0] = 0x59; 358 /* NB: b0[1] set below */ 359 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); 360 b0[8] = pn >> 40; 361 b0[9] = pn >> 32; 362 b0[10] = pn >> 24; 363 b0[11] = pn >> 16; 364 b0[12] = pn >> 8; 365 b0[13] = pn >> 0; 366 b0[14] = (dlen >> 8) & 0xff; 367 b0[15] = dlen & 0xff; 368 369 /* AAD: 370 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one 371 * A1 | A2 | A3 372 * SC with bits 4..15 (seq#) masked to zero 373 * A4 (if present) 374 * QC (if present) 375 */ 376 aad[0] = 0; /* AAD length >> 8 */ 377 /* NB: aad[1] set below */ 378 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ 379 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ 380 /* NB: we know 3 addresses are contiguous */ 381 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); 382 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; 383 aad[23] = 0; /* all bits masked */ 384 /* 385 * Construct variable-length portion of AAD based 386 * on whether this is a 4-address frame/QOS frame. 387 * We always zero-pad to 32 bytes before running it 388 * through the cipher. 389 * 390 * We also fill in the priority bits of the CCM 391 * initial block as we know whether or not we have 392 * a QOS frame. 393 */ 394 if (IEEE80211_IS_DSTODS(wh)) { 395 IEEE80211_ADDR_COPY(aad + 24, 396 ((struct ieee80211_frame_addr4 *)wh)->i_addr4); 397 if (IS_QOS_DATA(wh)) { 398 struct ieee80211_qosframe_addr4 *qwh4 = 399 (struct ieee80211_qosframe_addr4 *) wh; 400 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ 401 aad[31] = 0; 402 b0[1] = aad[30]; 403 aad[1] = 22 + IEEE80211_ADDR_LEN + 2; 404 } else { 405 *(uint16_t *)&aad[30] = 0; 406 b0[1] = 0; 407 aad[1] = 22 + IEEE80211_ADDR_LEN; 408 } 409 } else { 410 if (IS_QOS_DATA(wh)) { 411 struct ieee80211_qosframe *qwh = 412 (struct ieee80211_qosframe*) wh; 413 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ 414 aad[25] = 0; 415 b0[1] = aad[24]; 416 aad[1] = 22 + 2; 417 } else { 418 *(uint16_t *)&aad[24] = 0; 419 b0[1] = 0; 420 aad[1] = 22; 421 } 422 *(uint16_t *)&aad[26] = 0; 423 *(uint32_t *)&aad[28] = 0; 424 } 425 426 /* Start with the first block and AAD */ 427 rijndael_encrypt(ctx, b0, auth); 428 xor_block(auth, aad, AES_BLOCK_LEN); 429 rijndael_encrypt(ctx, auth, auth); 430 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 431 rijndael_encrypt(ctx, auth, auth); 432 b0[0] &= 0x07; 433 b0[14] = b0[15] = 0; 434 rijndael_encrypt(ctx, b0, s0); 435 #undef IS_QOS_DATA 436 } 437 438 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ 439 /* Authentication */ \ 440 xor_block(_b, _pos, _len); \ 441 rijndael_encrypt(&ctx->cc_aes, _b, _b); \ 442 /* Encryption, with counter */ \ 443 _b0[14] = (_i >> 8) & 0xff; \ 444 _b0[15] = _i & 0xff; \ 445 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ 446 xor_block(_pos, _e, _len); \ 447 } while (0) 448 449 static int 450 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 451 { 452 struct ccmp_ctx *ctx = key->wk_private; 453 struct ieee80211_frame *wh; 454 struct mbuf *m = m0; 455 int data_len, i, space; 456 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], 457 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; 458 uint8_t *pos; 459 460 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 461 462 wh = mtod(m, struct ieee80211_frame *); 463 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); 464 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, 465 data_len, b0, aad, b, s0); 466 467 i = 1; 468 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 469 /* NB: assumes header is entirely in first mbuf */ 470 space = m->m_len - (hdrlen + ccmp.ic_header); 471 for (;;) { 472 if (space > data_len) 473 space = data_len; 474 /* 475 * Do full blocks. 476 */ 477 while (space >= AES_BLOCK_LEN) { 478 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); 479 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 480 data_len -= AES_BLOCK_LEN; 481 i++; 482 } 483 if (data_len <= 0) /* no more data */ 484 break; 485 m = m->m_next; 486 if (m == NULL) { /* last buffer */ 487 if (space != 0) { 488 /* 489 * Short last block. 490 */ 491 CCMP_ENCRYPT(i, b, b0, pos, e, space); 492 } 493 break; 494 } 495 if (space != 0) { 496 uint8_t *pos_next; 497 int space_next; 498 int len, dl, sp; 499 struct mbuf *n; 500 501 /* 502 * Block straddles one or more mbufs, gather data 503 * into the block buffer b, apply the cipher, then 504 * scatter the results back into the mbuf chain. 505 * The buffer will automatically get space bytes 506 * of data at offset 0 copied in+out by the 507 * CCMP_ENCRYPT request so we must take care of 508 * the remaining data. 509 */ 510 n = m; 511 dl = data_len; 512 sp = space; 513 for (;;) { 514 pos_next = mtod(n, uint8_t *); 515 len = min(dl, AES_BLOCK_LEN); 516 space_next = len > sp ? len - sp : 0; 517 if (n->m_len >= space_next) { 518 /* 519 * This mbuf has enough data; just grab 520 * what we need and stop. 521 */ 522 xor_block(b+sp, pos_next, space_next); 523 break; 524 } 525 /* 526 * This mbuf's contents are insufficient, 527 * take 'em all and prepare to advance to 528 * the next mbuf. 529 */ 530 xor_block(b+sp, pos_next, n->m_len); 531 sp += n->m_len, dl -= n->m_len; 532 n = n->m_next; 533 if (n == NULL) 534 break; 535 } 536 537 CCMP_ENCRYPT(i, b, b0, pos, e, space); 538 539 /* NB: just like above, but scatter data to mbufs */ 540 dl = data_len; 541 sp = space; 542 for (;;) { 543 pos_next = mtod(m, uint8_t *); 544 len = min(dl, AES_BLOCK_LEN); 545 space_next = len > sp ? len - sp : 0; 546 if (m->m_len >= space_next) { 547 xor_block(pos_next, e+sp, space_next); 548 break; 549 } 550 xor_block(pos_next, e+sp, m->m_len); 551 sp += m->m_len, dl -= m->m_len; 552 m = m->m_next; 553 if (m == NULL) 554 goto done; 555 } 556 /* 557 * Do bookkeeping. m now points to the last mbuf 558 * we grabbed data from. We know we consumed a 559 * full block of data as otherwise we'd have hit 560 * the end of the mbuf chain, so deduct from data_len. 561 * Otherwise advance the block number (i) and setup 562 * pos+space to reflect contents of the new mbuf. 563 */ 564 data_len -= AES_BLOCK_LEN; 565 i++; 566 pos = pos_next + space_next; 567 space = m->m_len - space_next; 568 } else { 569 /* 570 * Setup for next buffer. 571 */ 572 pos = mtod(m, uint8_t *); 573 space = m->m_len; 574 } 575 } 576 done: 577 /* tack on MIC */ 578 xor_block(b, s0, ccmp.ic_trailer); 579 return m_append(m0, ccmp.ic_trailer, b); 580 } 581 #undef CCMP_ENCRYPT 582 583 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ 584 /* Decrypt, with counter */ \ 585 _b0[14] = (_i >> 8) & 0xff; \ 586 _b0[15] = _i & 0xff; \ 587 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ 588 xor_block(_pos, _b, _len); \ 589 /* Authentication */ \ 590 xor_block(_a, _pos, _len); \ 591 rijndael_encrypt(&ctx->cc_aes, _a, _a); \ 592 } while (0) 593 594 static int 595 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen) 596 { 597 struct ccmp_ctx *ctx = key->wk_private; 598 struct ieee80211vap *vap = ctx->cc_vap; 599 struct ieee80211_frame *wh; 600 uint8_t aad[2 * AES_BLOCK_LEN]; 601 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; 602 uint8_t mic[AES_BLOCK_LEN]; 603 size_t data_len; 604 int i; 605 uint8_t *pos; 606 u_int space; 607 608 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 609 610 wh = mtod(m, struct ieee80211_frame *); 611 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer); 612 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b); 613 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic); 614 xor_block(mic, b, ccmp.ic_trailer); 615 616 i = 1; 617 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 618 space = m->m_len - (hdrlen + ccmp.ic_header); 619 for (;;) { 620 if (space > data_len) 621 space = data_len; 622 while (space >= AES_BLOCK_LEN) { 623 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); 624 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 625 data_len -= AES_BLOCK_LEN; 626 i++; 627 } 628 if (data_len <= 0) /* no more data */ 629 break; 630 m = m->m_next; 631 if (m == NULL) { /* last buffer */ 632 if (space != 0) /* short last block */ 633 CCMP_DECRYPT(i, b, b0, pos, a, space); 634 break; 635 } 636 if (space != 0) { 637 uint8_t *pos_next; 638 u_int space_next; 639 u_int len; 640 641 /* 642 * Block straddles buffers, split references. We 643 * do not handle splits that require >2 buffers 644 * since rx'd frames are never badly fragmented 645 * because drivers typically recv in clusters. 646 */ 647 pos_next = mtod(m, uint8_t *); 648 len = min(data_len, AES_BLOCK_LEN); 649 space_next = len > space ? len - space : 0; 650 KASSERT(m->m_len >= space_next, 651 ("not enough data in following buffer, " 652 "m_len %u need %u\n", m->m_len, space_next)); 653 654 xor_block(b+space, pos_next, space_next); 655 CCMP_DECRYPT(i, b, b0, pos, a, space); 656 xor_block(pos_next, b+space, space_next); 657 data_len -= len; 658 i++; 659 660 pos = pos_next + space_next; 661 space = m->m_len - space_next; 662 } else { 663 /* 664 * Setup for next buffer. 665 */ 666 pos = mtod(m, uint8_t *); 667 space = m->m_len; 668 } 669 } 670 if (memcmp(mic, a, ccmp.ic_trailer) != 0) { 671 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 672 "%s", "AES-CCM decrypt failed; MIC mismatch"); 673 vap->iv_stats.is_rx_ccmpmic++; 674 return 0; 675 } 676 return 1; 677 } 678 #undef CCMP_DECRYPT 679 680 /* 681 * Module glue. 682 */ 683 IEEE80211_CRYPTO_MODULE(ccmp, 1); 684