1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 /* 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 const struct ieee80211_frame *wh; 166 struct ccmp_ctx *ctx = k->wk_private; 167 struct ieee80211com *ic = ctx->cc_ic; 168 uint8_t *ivp; 169 int hdrlen; 170 int is_mgmt; 171 172 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 173 wh = mtod(m, const struct ieee80211_frame *); 174 is_mgmt = IEEE80211_IS_MGMT(wh); 175 176 /* 177 * Check to see if we need to insert IV/MIC. 178 * 179 * Some offload devices don't require the IV to be inserted 180 * as part of the hardware encryption. 181 */ 182 if (is_mgmt && (k->wk_flags & IEEE80211_KEY_NOIVMGT)) 183 return 1; 184 if ((! is_mgmt) && (k->wk_flags & IEEE80211_KEY_NOIV)) 185 return 1; 186 187 /* 188 * Copy down 802.11 header and add the IV, KeyID, and ExtIV. 189 */ 190 M_PREPEND(m, ccmp.ic_header, IEEE80211_M_NOWAIT); 191 if (m == NULL) 192 return 0; 193 ivp = mtod(m, uint8_t *); 194 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen); 195 ivp += hdrlen; 196 197 ccmp_setiv(k, ivp); 198 199 /* 200 * Finally, do software encrypt if needed. 201 */ 202 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) && 203 !ccmp_encrypt(k, m, hdrlen)) 204 return 0; 205 206 return 1; 207 } 208 209 /* 210 * Add MIC to the frame as needed. 211 */ 212 static int 213 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force) 214 { 215 216 return 1; 217 } 218 219 static __inline uint64_t 220 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) 221 { 222 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); 223 uint16_t iv16 = (b4 << 0) | (b5 << 8); 224 return (((uint64_t)iv16) << 32) | iv32; 225 } 226 227 /* 228 * Validate and strip privacy headers (and trailer) for a 229 * received frame. The specified key should be correct but 230 * is also verified. 231 */ 232 static int 233 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 234 { 235 const struct ieee80211_rx_stats *rxs; 236 struct ccmp_ctx *ctx = k->wk_private; 237 struct ieee80211vap *vap = ctx->cc_vap; 238 struct ieee80211_frame *wh; 239 uint8_t *ivp, tid; 240 uint64_t pn; 241 bool noreplaycheck; 242 243 rxs = ieee80211_get_rx_params_ptr(m); 244 245 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP)) 246 goto finish; 247 248 /* 249 * Header should have extended IV and sequence number; 250 * verify the former and validate the latter. 251 */ 252 wh = mtod(m, struct ieee80211_frame *); 253 ivp = mtod(m, uint8_t *) + hdrlen; 254 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 255 /* 256 * No extended IV; discard frame. 257 */ 258 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 259 "%s", "missing ExtIV for AES-CCM cipher"); 260 vap->iv_stats.is_rx_ccmpformat++; 261 return 0; 262 } 263 tid = ieee80211_gettid(wh); 264 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 265 266 noreplaycheck = (k->wk_flags & IEEE80211_KEY_NOREPLAY) != 0; 267 noreplaycheck |= (rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_PN_VALIDATED) != 0; 268 if (pn <= k->wk_keyrsc[tid] && !noreplaycheck) { 269 /* 270 * Replay violation. 271 */ 272 ieee80211_notify_replay_failure(vap, wh, k, pn, tid); 273 vap->iv_stats.is_rx_ccmpreplay++; 274 return 0; 275 } 276 277 /* 278 * Check if the device handled the decrypt in hardware. 279 * If so we just strip the header; otherwise we need to 280 * handle the decrypt in software. Note that for the 281 * latter we leave the header in place for use in the 282 * decryption work. 283 */ 284 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) && 285 !ccmp_decrypt(k, pn, m, hdrlen)) 286 return 0; 287 288 finish: 289 /* 290 * Copy up 802.11 header and strip crypto bits. 291 */ 292 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) { 293 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, 294 hdrlen); 295 m_adj(m, ccmp.ic_header); 296 } 297 298 /* 299 * XXX TODO: see if MMIC_STRIP also covers CCMP MIC trailer. 300 */ 301 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP))) 302 m_adj(m, -ccmp.ic_trailer); 303 304 /* 305 * Ok to update rsc now. 306 */ 307 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) { 308 /* 309 * Do not go backwards in the IEEE80211_KEY_NOREPLAY cases 310 * or in case hardware has checked but frames are arriving 311 * reordered (e.g., LinuxKPI drivers doing RSS which we are 312 * not prepared for at all). 313 */ 314 if (pn > k->wk_keyrsc[tid]) 315 k->wk_keyrsc[tid] = pn; 316 } 317 318 return 1; 319 } 320 321 /* 322 * Verify and strip MIC from the frame. 323 */ 324 static int 325 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force) 326 { 327 return 1; 328 } 329 330 static __inline void 331 xor_block(uint8_t *b, const uint8_t *a, size_t len) 332 { 333 int i; 334 for (i = 0; i < len; i++) 335 b[i] ^= a[i]; 336 } 337 338 /* 339 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 340 * 341 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> 342 * 343 * This program is free software; you can redistribute it and/or modify 344 * it under the terms of the GNU General Public License version 2 as 345 * published by the Free Software Foundation. See README and COPYING for 346 * more details. 347 * 348 * Alternatively, this software may be distributed under the terms of BSD 349 * license. 350 */ 351 352 static void 353 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, 354 u_int64_t pn, size_t dlen, 355 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], 356 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) 357 { 358 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh) 359 360 /* CCM Initial Block: 361 * Flag (Include authentication header, M=3 (8-octet MIC), 362 * L=1 (2-octet Dlen)) 363 * Nonce: 0x00 | A2 | PN 364 * Dlen */ 365 b0[0] = 0x59; 366 /* NB: b0[1] set below */ 367 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); 368 b0[8] = pn >> 40; 369 b0[9] = pn >> 32; 370 b0[10] = pn >> 24; 371 b0[11] = pn >> 16; 372 b0[12] = pn >> 8; 373 b0[13] = pn >> 0; 374 b0[14] = (dlen >> 8) & 0xff; 375 b0[15] = dlen & 0xff; 376 377 /* AAD: 378 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one 379 * A1 | A2 | A3 380 * SC with bits 4..15 (seq#) masked to zero 381 * A4 (if present) 382 * QC (if present) 383 */ 384 aad[0] = 0; /* AAD length >> 8 */ 385 /* NB: aad[1] set below */ 386 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ 387 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ 388 /* NB: we know 3 addresses are contiguous */ 389 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); 390 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; 391 aad[23] = 0; /* all bits masked */ 392 /* 393 * Construct variable-length portion of AAD based 394 * on whether this is a 4-address frame/QOS frame. 395 * We always zero-pad to 32 bytes before running it 396 * through the cipher. 397 * 398 * We also fill in the priority bits of the CCM 399 * initial block as we know whether or not we have 400 * a QOS frame. 401 */ 402 if (IEEE80211_IS_DSTODS(wh)) { 403 IEEE80211_ADDR_COPY(aad + 24, 404 ((struct ieee80211_frame_addr4 *)wh)->i_addr4); 405 if (IS_QOS_DATA(wh)) { 406 struct ieee80211_qosframe_addr4 *qwh4 = 407 (struct ieee80211_qosframe_addr4 *) wh; 408 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ 409 aad[31] = 0; 410 b0[1] = aad[30]; 411 aad[1] = 22 + IEEE80211_ADDR_LEN + 2; 412 } else { 413 *(uint16_t *)&aad[30] = 0; 414 b0[1] = 0; 415 aad[1] = 22 + IEEE80211_ADDR_LEN; 416 } 417 } else { 418 if (IS_QOS_DATA(wh)) { 419 struct ieee80211_qosframe *qwh = 420 (struct ieee80211_qosframe*) wh; 421 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ 422 aad[25] = 0; 423 b0[1] = aad[24]; 424 aad[1] = 22 + 2; 425 } else { 426 *(uint16_t *)&aad[24] = 0; 427 b0[1] = 0; 428 aad[1] = 22; 429 } 430 *(uint16_t *)&aad[26] = 0; 431 *(uint32_t *)&aad[28] = 0; 432 } 433 434 /* Start with the first block and AAD */ 435 rijndael_encrypt(ctx, b0, auth); 436 xor_block(auth, aad, AES_BLOCK_LEN); 437 rijndael_encrypt(ctx, auth, auth); 438 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 439 rijndael_encrypt(ctx, auth, auth); 440 b0[0] &= 0x07; 441 b0[14] = b0[15] = 0; 442 rijndael_encrypt(ctx, b0, s0); 443 #undef IS_QOS_DATA 444 } 445 446 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ 447 /* Authentication */ \ 448 xor_block(_b, _pos, _len); \ 449 rijndael_encrypt(&ctx->cc_aes, _b, _b); \ 450 /* Encryption, with counter */ \ 451 _b0[14] = (_i >> 8) & 0xff; \ 452 _b0[15] = _i & 0xff; \ 453 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ 454 xor_block(_pos, _e, _len); \ 455 } while (0) 456 457 static int 458 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 459 { 460 struct ccmp_ctx *ctx = key->wk_private; 461 struct ieee80211_frame *wh; 462 struct mbuf *m = m0; 463 int data_len, i, space; 464 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], 465 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; 466 uint8_t *pos; 467 468 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 469 470 wh = mtod(m, struct ieee80211_frame *); 471 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); 472 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, 473 data_len, b0, aad, b, s0); 474 475 i = 1; 476 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 477 /* NB: assumes header is entirely in first mbuf */ 478 space = m->m_len - (hdrlen + ccmp.ic_header); 479 for (;;) { 480 if (space > data_len) 481 space = data_len; 482 /* 483 * Do full blocks. 484 */ 485 while (space >= AES_BLOCK_LEN) { 486 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); 487 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 488 data_len -= AES_BLOCK_LEN; 489 i++; 490 } 491 if (data_len <= 0) /* no more data */ 492 break; 493 m = m->m_next; 494 if (m == NULL) { /* last buffer */ 495 if (space != 0) { 496 /* 497 * Short last block. 498 */ 499 CCMP_ENCRYPT(i, b, b0, pos, e, space); 500 } 501 break; 502 } 503 if (space != 0) { 504 uint8_t *pos_next; 505 int space_next; 506 int len, dl, sp; 507 struct mbuf *n; 508 509 /* 510 * Block straddles one or more mbufs, gather data 511 * into the block buffer b, apply the cipher, then 512 * scatter the results back into the mbuf chain. 513 * The buffer will automatically get space bytes 514 * of data at offset 0 copied in+out by the 515 * CCMP_ENCRYPT request so we must take care of 516 * the remaining data. 517 */ 518 n = m; 519 dl = data_len; 520 sp = space; 521 for (;;) { 522 pos_next = mtod(n, uint8_t *); 523 len = min(dl, AES_BLOCK_LEN); 524 space_next = len > sp ? len - sp : 0; 525 if (n->m_len >= space_next) { 526 /* 527 * This mbuf has enough data; just grab 528 * what we need and stop. 529 */ 530 xor_block(b+sp, pos_next, space_next); 531 break; 532 } 533 /* 534 * This mbuf's contents are insufficient, 535 * take 'em all and prepare to advance to 536 * the next mbuf. 537 */ 538 xor_block(b+sp, pos_next, n->m_len); 539 sp += n->m_len, dl -= n->m_len; 540 n = n->m_next; 541 if (n == NULL) 542 break; 543 } 544 545 CCMP_ENCRYPT(i, b, b0, pos, e, space); 546 547 /* NB: just like above, but scatter data to mbufs */ 548 dl = data_len; 549 sp = space; 550 for (;;) { 551 pos_next = mtod(m, uint8_t *); 552 len = min(dl, AES_BLOCK_LEN); 553 space_next = len > sp ? len - sp : 0; 554 if (m->m_len >= space_next) { 555 xor_block(pos_next, e+sp, space_next); 556 break; 557 } 558 xor_block(pos_next, e+sp, m->m_len); 559 sp += m->m_len, dl -= m->m_len; 560 m = m->m_next; 561 if (m == NULL) 562 goto done; 563 } 564 /* 565 * Do bookkeeping. m now points to the last mbuf 566 * we grabbed data from. We know we consumed a 567 * full block of data as otherwise we'd have hit 568 * the end of the mbuf chain, so deduct from data_len. 569 * Otherwise advance the block number (i) and setup 570 * pos+space to reflect contents of the new mbuf. 571 */ 572 data_len -= AES_BLOCK_LEN; 573 i++; 574 pos = pos_next + space_next; 575 space = m->m_len - space_next; 576 } else { 577 /* 578 * Setup for next buffer. 579 */ 580 pos = mtod(m, uint8_t *); 581 space = m->m_len; 582 } 583 } 584 done: 585 /* tack on MIC */ 586 xor_block(b, s0, ccmp.ic_trailer); 587 return m_append(m0, ccmp.ic_trailer, b); 588 } 589 #undef CCMP_ENCRYPT 590 591 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ 592 /* Decrypt, with counter */ \ 593 _b0[14] = (_i >> 8) & 0xff; \ 594 _b0[15] = _i & 0xff; \ 595 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ 596 xor_block(_pos, _b, _len); \ 597 /* Authentication */ \ 598 xor_block(_a, _pos, _len); \ 599 rijndael_encrypt(&ctx->cc_aes, _a, _a); \ 600 } while (0) 601 602 static int 603 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen) 604 { 605 const struct ieee80211_rx_stats *rxs; 606 struct ccmp_ctx *ctx = key->wk_private; 607 struct ieee80211vap *vap = ctx->cc_vap; 608 struct ieee80211_frame *wh; 609 uint8_t aad[2 * AES_BLOCK_LEN]; 610 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; 611 uint8_t mic[AES_BLOCK_LEN]; 612 size_t data_len; 613 int i; 614 uint8_t *pos; 615 u_int space; 616 617 rxs = ieee80211_get_rx_params_ptr(m); 618 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED) != 0) 619 return (1); 620 621 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 622 623 wh = mtod(m, struct ieee80211_frame *); 624 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer); 625 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b); 626 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic); 627 xor_block(mic, b, ccmp.ic_trailer); 628 629 i = 1; 630 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 631 space = m->m_len - (hdrlen + ccmp.ic_header); 632 for (;;) { 633 if (space > data_len) 634 space = data_len; 635 while (space >= AES_BLOCK_LEN) { 636 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); 637 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 638 data_len -= AES_BLOCK_LEN; 639 i++; 640 } 641 if (data_len <= 0) /* no more data */ 642 break; 643 m = m->m_next; 644 if (m == NULL) { /* last buffer */ 645 if (space != 0) /* short last block */ 646 CCMP_DECRYPT(i, b, b0, pos, a, space); 647 break; 648 } 649 if (space != 0) { 650 uint8_t *pos_next; 651 u_int space_next; 652 u_int len; 653 654 /* 655 * Block straddles buffers, split references. We 656 * do not handle splits that require >2 buffers 657 * since rx'd frames are never badly fragmented 658 * because drivers typically recv in clusters. 659 */ 660 pos_next = mtod(m, uint8_t *); 661 len = min(data_len, AES_BLOCK_LEN); 662 space_next = len > space ? len - space : 0; 663 KASSERT(m->m_len >= space_next, 664 ("not enough data in following buffer, " 665 "m_len %u need %u\n", m->m_len, space_next)); 666 667 xor_block(b+space, pos_next, space_next); 668 CCMP_DECRYPT(i, b, b0, pos, a, space); 669 xor_block(pos_next, b+space, space_next); 670 data_len -= len; 671 i++; 672 673 pos = pos_next + space_next; 674 space = m->m_len - space_next; 675 } else { 676 /* 677 * Setup for next buffer. 678 */ 679 pos = mtod(m, uint8_t *); 680 space = m->m_len; 681 } 682 } 683 684 /* 685 * If the MIC (we use MMIC despite not being Micheal) was stripped 686 * by HW/driver we are done. 687 */ 688 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP) != 0) 689 return (1); 690 691 if (memcmp(mic, a, ccmp.ic_trailer) != 0) { 692 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 693 "%s", "AES-CCM decrypt failed; MIC mismatch"); 694 vap->iv_stats.is_rx_ccmpmic++; 695 return 0; 696 } 697 return 1; 698 } 699 #undef CCMP_DECRYPT 700 701 /* 702 * Module glue. 703 */ 704 IEEE80211_CRYPTO_MODULE(ccmp, 1); 705