Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_crypto_ccmp.c
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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: releng/11.0/sys/net80211/ieee80211_crypto_ccmp.c 288526 2015-10-03 00:50:13Z adrian $"); 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_media.h> 49 #include <net/ethernet.h> 50 51 #include <net80211/ieee80211_var.h> 52 53 #include <crypto/rijndael/rijndael.h> 54 55 #define AES_BLOCK_LEN 16 56 57 struct ccmp_ctx { 58 struct ieee80211vap *cc_vap; /* for diagnostics+statistics */ 59 struct ieee80211com *cc_ic; 60 rijndael_ctx cc_aes; 61 }; 62 63 static void *ccmp_attach(struct ieee80211vap *, struct ieee80211_key *); 64 static void ccmp_detach(struct ieee80211_key *); 65 static int ccmp_setkey(struct ieee80211_key *); 66 static void ccmp_setiv(struct ieee80211_key *, uint8_t *); 67 static int ccmp_encap(struct ieee80211_key *, struct mbuf *); 68 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); 69 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); 70 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); 71 72 static const struct ieee80211_cipher ccmp = { 73 .ic_name = "AES-CCM", 74 .ic_cipher = IEEE80211_CIPHER_AES_CCM, 75 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + 76 IEEE80211_WEP_EXTIVLEN, 77 .ic_trailer = IEEE80211_WEP_MICLEN, 78 .ic_miclen = 0, 79 .ic_attach = ccmp_attach, 80 .ic_detach = ccmp_detach, 81 .ic_setkey = ccmp_setkey, 82 .ic_setiv = ccmp_setiv, 83 .ic_encap = ccmp_encap, 84 .ic_decap = ccmp_decap, 85 .ic_enmic = ccmp_enmic, 86 .ic_demic = ccmp_demic, 87 }; 88 89 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 90 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, 91 struct mbuf *, int hdrlen); 92 93 /* number of references from net80211 layer */ 94 static int nrefs = 0; 95 96 static void * 97 ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k) 98 { 99 struct ccmp_ctx *ctx; 100 101 ctx = (struct ccmp_ctx *) IEEE80211_MALLOC(sizeof(struct ccmp_ctx), 102 M_80211_CRYPTO, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 103 if (ctx == NULL) { 104 vap->iv_stats.is_crypto_nomem++; 105 return NULL; 106 } 107 ctx->cc_vap = vap; 108 ctx->cc_ic = vap->iv_ic; 109 nrefs++; /* NB: we assume caller locking */ 110 return ctx; 111 } 112 113 static void 114 ccmp_detach(struct ieee80211_key *k) 115 { 116 struct ccmp_ctx *ctx = k->wk_private; 117 118 IEEE80211_FREE(ctx, M_80211_CRYPTO); 119 KASSERT(nrefs > 0, ("imbalanced attach/detach")); 120 nrefs--; /* NB: we assume caller locking */ 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_vap, 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_SWENCRYPT) 135 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY); 136 return 1; 137 } 138 139 static void 140 ccmp_setiv(struct ieee80211_key *k, uint8_t *ivp) 141 { 142 struct ccmp_ctx *ctx = k->wk_private; 143 struct ieee80211vap *vap = ctx->cc_vap; 144 uint8_t keyid; 145 146 keyid = ieee80211_crypto_get_keyid(vap, k) << 6; 147 148 k->wk_keytsc++; 149 ivp[0] = k->wk_keytsc >> 0; /* PN0 */ 150 ivp[1] = k->wk_keytsc >> 8; /* PN1 */ 151 ivp[2] = 0; /* Reserved */ 152 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ 153 ivp[4] = k->wk_keytsc >> 16; /* PN2 */ 154 ivp[5] = k->wk_keytsc >> 24; /* PN3 */ 155 ivp[6] = k->wk_keytsc >> 32; /* PN4 */ 156 ivp[7] = k->wk_keytsc >> 40; /* PN5 */ 157 } 158 159 /* 160 * Add privacy headers appropriate for the specified key. 161 */ 162 static int 163 ccmp_encap(struct ieee80211_key *k, struct mbuf *m) 164 { 165 struct ccmp_ctx *ctx = k->wk_private; 166 struct ieee80211com *ic = ctx->cc_ic; 167 uint8_t *ivp; 168 int hdrlen; 169 170 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 171 172 /* 173 * Copy down 802.11 header and add the IV, KeyID, and ExtIV. 174 */ 175 M_PREPEND(m, ccmp.ic_header, M_NOWAIT); 176 if (m == NULL) 177 return 0; 178 ivp = mtod(m, uint8_t *); 179 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen); 180 ivp += hdrlen; 181 182 ccmp_setiv(k, ivp); 183 184 /* 185 * Finally, do software encrypt if needed. 186 */ 187 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) && 188 !ccmp_encrypt(k, m, hdrlen)) 189 return 0; 190 191 return 1; 192 } 193 194 /* 195 * Add MIC to the frame as needed. 196 */ 197 static int 198 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force) 199 { 200 201 return 1; 202 } 203 204 static __inline uint64_t 205 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) 206 { 207 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); 208 uint16_t iv16 = (b4 << 0) | (b5 << 8); 209 return (((uint64_t)iv16) << 32) | iv32; 210 } 211 212 /* 213 * Validate and strip privacy headers (and trailer) for a 214 * received frame. The specified key should be correct but 215 * is also verified. 216 */ 217 static int 218 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 219 { 220 struct ccmp_ctx *ctx = k->wk_private; 221 struct ieee80211vap *vap = ctx->cc_vap; 222 struct ieee80211_frame *wh; 223 uint8_t *ivp, tid; 224 uint64_t pn; 225 226 /* 227 * Header should have extended IV and sequence number; 228 * verify the former and validate the latter. 229 */ 230 wh = mtod(m, struct ieee80211_frame *); 231 ivp = mtod(m, uint8_t *) + hdrlen; 232 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 233 /* 234 * No extended IV; discard frame. 235 */ 236 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 237 "%s", "missing ExtIV for AES-CCM cipher"); 238 vap->iv_stats.is_rx_ccmpformat++; 239 return 0; 240 } 241 tid = ieee80211_gettid(wh); 242 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 243 if (pn <= k->wk_keyrsc[tid] && 244 (k->wk_flags & IEEE80211_KEY_NOREPLAY) == 0) { 245 /* 246 * Replay violation. 247 */ 248 ieee80211_notify_replay_failure(vap, wh, k, pn, tid); 249 vap->iv_stats.is_rx_ccmpreplay++; 250 return 0; 251 } 252 253 /* 254 * Check if the device handled the decrypt in hardware. 255 * If so we just strip the header; otherwise we need to 256 * handle the decrypt in software. Note that for the 257 * latter we leave the header in place for use in the 258 * decryption work. 259 */ 260 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) && 261 !ccmp_decrypt(k, pn, m, hdrlen)) 262 return 0; 263 264 /* 265 * Copy up 802.11 header and strip crypto bits. 266 */ 267 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, hdrlen); 268 m_adj(m, ccmp.ic_header); 269 m_adj(m, -ccmp.ic_trailer); 270 271 /* 272 * Ok to update rsc now. 273 */ 274 k->wk_keyrsc[tid] = pn; 275 276 return 1; 277 } 278 279 /* 280 * Verify and strip MIC from the frame. 281 */ 282 static int 283 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force) 284 { 285 return 1; 286 } 287 288 static __inline void 289 xor_block(uint8_t *b, const uint8_t *a, size_t len) 290 { 291 int i; 292 for (i = 0; i < len; i++) 293 b[i] ^= a[i]; 294 } 295 296 /* 297 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 298 * 299 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> 300 * 301 * This program is free software; you can redistribute it and/or modify 302 * it under the terms of the GNU General Public License version 2 as 303 * published by the Free Software Foundation. See README and COPYING for 304 * more details. 305 * 306 * Alternatively, this software may be distributed under the terms of BSD 307 * license. 308 */ 309 310 static void 311 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, 312 u_int64_t pn, size_t dlen, 313 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], 314 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) 315 { 316 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh) 317 318 /* CCM Initial Block: 319 * Flag (Include authentication header, M=3 (8-octet MIC), 320 * L=1 (2-octet Dlen)) 321 * Nonce: 0x00 | A2 | PN 322 * Dlen */ 323 b0[0] = 0x59; 324 /* NB: b0[1] set below */ 325 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); 326 b0[8] = pn >> 40; 327 b0[9] = pn >> 32; 328 b0[10] = pn >> 24; 329 b0[11] = pn >> 16; 330 b0[12] = pn >> 8; 331 b0[13] = pn >> 0; 332 b0[14] = (dlen >> 8) & 0xff; 333 b0[15] = dlen & 0xff; 334 335 /* AAD: 336 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one 337 * A1 | A2 | A3 338 * SC with bits 4..15 (seq#) masked to zero 339 * A4 (if present) 340 * QC (if present) 341 */ 342 aad[0] = 0; /* AAD length >> 8 */ 343 /* NB: aad[1] set below */ 344 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ 345 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ 346 /* NB: we know 3 addresses are contiguous */ 347 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); 348 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; 349 aad[23] = 0; /* all bits masked */ 350 /* 351 * Construct variable-length portion of AAD based 352 * on whether this is a 4-address frame/QOS frame. 353 * We always zero-pad to 32 bytes before running it 354 * through the cipher. 355 * 356 * We also fill in the priority bits of the CCM 357 * initial block as we know whether or not we have 358 * a QOS frame. 359 */ 360 if (IEEE80211_IS_DSTODS(wh)) { 361 IEEE80211_ADDR_COPY(aad + 24, 362 ((struct ieee80211_frame_addr4 *)wh)->i_addr4); 363 if (IS_QOS_DATA(wh)) { 364 struct ieee80211_qosframe_addr4 *qwh4 = 365 (struct ieee80211_qosframe_addr4 *) wh; 366 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ 367 aad[31] = 0; 368 b0[1] = aad[30]; 369 aad[1] = 22 + IEEE80211_ADDR_LEN + 2; 370 } else { 371 *(uint16_t *)&aad[30] = 0; 372 b0[1] = 0; 373 aad[1] = 22 + IEEE80211_ADDR_LEN; 374 } 375 } else { 376 if (IS_QOS_DATA(wh)) { 377 struct ieee80211_qosframe *qwh = 378 (struct ieee80211_qosframe*) wh; 379 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ 380 aad[25] = 0; 381 b0[1] = aad[24]; 382 aad[1] = 22 + 2; 383 } else { 384 *(uint16_t *)&aad[24] = 0; 385 b0[1] = 0; 386 aad[1] = 22; 387 } 388 *(uint16_t *)&aad[26] = 0; 389 *(uint32_t *)&aad[28] = 0; 390 } 391 392 /* Start with the first block and AAD */ 393 rijndael_encrypt(ctx, b0, auth); 394 xor_block(auth, aad, AES_BLOCK_LEN); 395 rijndael_encrypt(ctx, auth, auth); 396 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 397 rijndael_encrypt(ctx, auth, auth); 398 b0[0] &= 0x07; 399 b0[14] = b0[15] = 0; 400 rijndael_encrypt(ctx, b0, s0); 401 #undef IS_QOS_DATA 402 } 403 404 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ 405 /* Authentication */ \ 406 xor_block(_b, _pos, _len); \ 407 rijndael_encrypt(&ctx->cc_aes, _b, _b); \ 408 /* Encryption, with counter */ \ 409 _b0[14] = (_i >> 8) & 0xff; \ 410 _b0[15] = _i & 0xff; \ 411 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ 412 xor_block(_pos, _e, _len); \ 413 } while (0) 414 415 static int 416 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 417 { 418 struct ccmp_ctx *ctx = key->wk_private; 419 struct ieee80211_frame *wh; 420 struct mbuf *m = m0; 421 int data_len, i, space; 422 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], 423 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; 424 uint8_t *pos; 425 426 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 427 428 wh = mtod(m, struct ieee80211_frame *); 429 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); 430 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, 431 data_len, b0, aad, b, s0); 432 433 i = 1; 434 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 435 /* NB: assumes header is entirely in first mbuf */ 436 space = m->m_len - (hdrlen + ccmp.ic_header); 437 for (;;) { 438 if (space > data_len) 439 space = data_len; 440 /* 441 * Do full blocks. 442 */ 443 while (space >= AES_BLOCK_LEN) { 444 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); 445 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 446 data_len -= AES_BLOCK_LEN; 447 i++; 448 } 449 if (data_len <= 0) /* no more data */ 450 break; 451 m = m->m_next; 452 if (m == NULL) { /* last buffer */ 453 if (space != 0) { 454 /* 455 * Short last block. 456 */ 457 CCMP_ENCRYPT(i, b, b0, pos, e, space); 458 } 459 break; 460 } 461 if (space != 0) { 462 uint8_t *pos_next; 463 int space_next; 464 int len, dl, sp; 465 struct mbuf *n; 466 467 /* 468 * Block straddles one or more mbufs, gather data 469 * into the block buffer b, apply the cipher, then 470 * scatter the results back into the mbuf chain. 471 * The buffer will automatically get space bytes 472 * of data at offset 0 copied in+out by the 473 * CCMP_ENCRYPT request so we must take care of 474 * the remaining data. 475 */ 476 n = m; 477 dl = data_len; 478 sp = space; 479 for (;;) { 480 pos_next = mtod(n, uint8_t *); 481 len = min(dl, AES_BLOCK_LEN); 482 space_next = len > sp ? len - sp : 0; 483 if (n->m_len >= space_next) { 484 /* 485 * This mbuf has enough data; just grab 486 * what we need and stop. 487 */ 488 xor_block(b+sp, pos_next, space_next); 489 break; 490 } 491 /* 492 * This mbuf's contents are insufficient, 493 * take 'em all and prepare to advance to 494 * the next mbuf. 495 */ 496 xor_block(b+sp, pos_next, n->m_len); 497 sp += n->m_len, dl -= n->m_len; 498 n = n->m_next; 499 if (n == NULL) 500 break; 501 } 502 503 CCMP_ENCRYPT(i, b, b0, pos, e, space); 504 505 /* NB: just like above, but scatter data to mbufs */ 506 dl = data_len; 507 sp = space; 508 for (;;) { 509 pos_next = mtod(m, uint8_t *); 510 len = min(dl, AES_BLOCK_LEN); 511 space_next = len > sp ? len - sp : 0; 512 if (m->m_len >= space_next) { 513 xor_block(pos_next, e+sp, space_next); 514 break; 515 } 516 xor_block(pos_next, e+sp, m->m_len); 517 sp += m->m_len, dl -= m->m_len; 518 m = m->m_next; 519 if (m == NULL) 520 goto done; 521 } 522 /* 523 * Do bookkeeping. m now points to the last mbuf 524 * we grabbed data from. We know we consumed a 525 * full block of data as otherwise we'd have hit 526 * the end of the mbuf chain, so deduct from data_len. 527 * Otherwise advance the block number (i) and setup 528 * pos+space to reflect contents of the new mbuf. 529 */ 530 data_len -= AES_BLOCK_LEN; 531 i++; 532 pos = pos_next + space_next; 533 space = m->m_len - space_next; 534 } else { 535 /* 536 * Setup for next buffer. 537 */ 538 pos = mtod(m, uint8_t *); 539 space = m->m_len; 540 } 541 } 542 done: 543 /* tack on MIC */ 544 xor_block(b, s0, ccmp.ic_trailer); 545 return m_append(m0, ccmp.ic_trailer, b); 546 } 547 #undef CCMP_ENCRYPT 548 549 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ 550 /* Decrypt, with counter */ \ 551 _b0[14] = (_i >> 8) & 0xff; \ 552 _b0[15] = _i & 0xff; \ 553 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ 554 xor_block(_pos, _b, _len); \ 555 /* Authentication */ \ 556 xor_block(_a, _pos, _len); \ 557 rijndael_encrypt(&ctx->cc_aes, _a, _a); \ 558 } while (0) 559 560 static int 561 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen) 562 { 563 struct ccmp_ctx *ctx = key->wk_private; 564 struct ieee80211vap *vap = ctx->cc_vap; 565 struct ieee80211_frame *wh; 566 uint8_t aad[2 * AES_BLOCK_LEN]; 567 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; 568 uint8_t mic[AES_BLOCK_LEN]; 569 size_t data_len; 570 int i; 571 uint8_t *pos; 572 u_int space; 573 574 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 575 576 wh = mtod(m, struct ieee80211_frame *); 577 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer); 578 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b); 579 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic); 580 xor_block(mic, b, ccmp.ic_trailer); 581 582 i = 1; 583 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 584 space = m->m_len - (hdrlen + ccmp.ic_header); 585 for (;;) { 586 if (space > data_len) 587 space = data_len; 588 while (space >= AES_BLOCK_LEN) { 589 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); 590 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 591 data_len -= AES_BLOCK_LEN; 592 i++; 593 } 594 if (data_len <= 0) /* no more data */ 595 break; 596 m = m->m_next; 597 if (m == NULL) { /* last buffer */ 598 if (space != 0) /* short last block */ 599 CCMP_DECRYPT(i, b, b0, pos, a, space); 600 break; 601 } 602 if (space != 0) { 603 uint8_t *pos_next; 604 u_int space_next; 605 u_int len; 606 607 /* 608 * Block straddles buffers, split references. We 609 * do not handle splits that require >2 buffers 610 * since rx'd frames are never badly fragmented 611 * because drivers typically recv in clusters. 612 */ 613 pos_next = mtod(m, uint8_t *); 614 len = min(data_len, AES_BLOCK_LEN); 615 space_next = len > space ? len - space : 0; 616 KASSERT(m->m_len >= space_next, 617 ("not enough data in following buffer, " 618 "m_len %u need %u\n", m->m_len, space_next)); 619 620 xor_block(b+space, pos_next, space_next); 621 CCMP_DECRYPT(i, b, b0, pos, a, space); 622 xor_block(pos_next, b+space, space_next); 623 data_len -= len; 624 i++; 625 626 pos = pos_next + space_next; 627 space = m->m_len - space_next; 628 } else { 629 /* 630 * Setup for next buffer. 631 */ 632 pos = mtod(m, uint8_t *); 633 space = m->m_len; 634 } 635 } 636 if (memcmp(mic, a, ccmp.ic_trailer) != 0) { 637 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 638 "%s", "AES-CCM decrypt failed; MIC mismatch"); 639 vap->iv_stats.is_rx_ccmpmic++; 640 return 0; 641 } 642 return 1; 643 } 644 #undef CCMP_DECRYPT 645 646 /* 647 * Module glue. 648 */ 649 IEEE80211_CRYPTO_MODULE(ccmp, 1);
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