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 * $FreeBSD: src/sys/net80211/ieee80211_crypto_ccmp.c,v 1.7.2.1 2005/12/22 19:02:08 sam Exp $ 32 * $DragonFly: src/sys/netproto/802_11/wlan_ccmp/ieee80211_crypto_ccmp.c,v 1.6 2007/09/15 07:19:23 sephe Exp $ 33 */ 34 35 /* 36 * IEEE 802.11i AES-CCMP crypto support. 37 * 38 * Part of this module is derived from similar code in the Host 39 * AP driver. The code is used with the consent of the author and 40 * it's license is included below. 41 */ 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/mbuf.h> 45 #include <sys/malloc.h> 46 #include <sys/kernel.h> 47 #include <sys/module.h> 48 49 #include <sys/socket.h> 50 51 #include <net/if.h> 52 #include <net/if_arp.h> 53 #include <net/if_media.h> 54 #include <net/ethernet.h> 55 56 #include <netproto/802_11/ieee80211_var.h> 57 58 #include <crypto/rijndael/rijndael.h> 59 60 #define AES_BLOCK_LEN 16 61 62 struct ccmp_ctx { 63 struct ieee80211com *cc_ic; /* for diagnostics */ 64 rijndael_ctx cc_aes; 65 }; 66 67 static void *ccmp_attach(struct ieee80211com *, struct ieee80211_key *); 68 static void ccmp_detach(struct ieee80211_key *); 69 static int ccmp_setkey(struct ieee80211_key *); 70 static int ccmp_encap(struct ieee80211_key *k, struct mbuf *, uint8_t keyid); 71 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); 72 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); 73 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); 74 static int ccmp_getiv(struct ieee80211_key *, struct ieee80211_crypto_iv *, 75 uint8_t); 76 static int ccmp_update(struct ieee80211_key *, 77 const struct ieee80211_crypto_iv *, 78 const struct ieee80211_frame *); 79 80 static const struct ieee80211_cipher ccmp = { 81 .ic_name = "AES-CCM", 82 .ic_cipher = IEEE80211_CIPHER_AES_CCM, 83 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + 84 IEEE80211_WEP_EXTIVLEN, 85 .ic_trailer = IEEE80211_WEP_MICLEN, 86 .ic_miclen = 0, 87 .ic_attach = ccmp_attach, 88 .ic_detach = ccmp_detach, 89 .ic_setkey = ccmp_setkey, 90 .ic_encap = ccmp_encap, 91 .ic_decap = ccmp_decap, 92 .ic_enmic = ccmp_enmic, 93 .ic_demic = ccmp_demic, 94 .ic_getiv = ccmp_getiv, 95 .ic_update = ccmp_update 96 }; 97 98 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 99 static int ccmp_decrypt(struct ieee80211_key *, uint64_t pn, 100 struct mbuf *, int hdrlen); 101 102 /* number of references from net80211 layer */ 103 static int nrefs = 0; 104 105 static void * 106 ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k) 107 { 108 struct ccmp_ctx *ctx; 109 110 ctx = kmalloc(sizeof(struct ccmp_ctx), M_DEVBUF, M_NOWAIT | M_ZERO); 111 if (ctx == NULL) { 112 ic->ic_stats.is_crypto_nomem++; 113 return NULL; 114 } 115 ctx->cc_ic = ic; 116 nrefs++; /* NB: we assume caller locking */ 117 return ctx; 118 } 119 120 static void 121 ccmp_detach(struct ieee80211_key *k) 122 { 123 struct ccmp_ctx *ctx = k->wk_private; 124 125 kfree(ctx, M_DEVBUF); 126 KASSERT(nrefs > 0, ("imbalanced attach/detach")); 127 nrefs--; /* NB: we assume caller locking */ 128 } 129 130 static int 131 ccmp_setkey(struct ieee80211_key *k) 132 { 133 struct ccmp_ctx *ctx = k->wk_private; 134 135 if (k->wk_keylen != (128/NBBY)) { 136 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 137 "%s: Invalid key length %u, expecting %u\n", 138 __func__, k->wk_keylen, 128/NBBY); 139 return 0; 140 } 141 if (k->wk_flags & IEEE80211_KEY_SWCRYPT) 142 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen * NBBY); 143 return 1; 144 } 145 146 /* 147 * Add privacy headers appropriate for the specified key. 148 */ 149 static int 150 ccmp_encap(struct ieee80211_key *k, struct mbuf *m, uint8_t keyid) 151 { 152 struct ccmp_ctx *ctx = k->wk_private; 153 struct ieee80211com *ic = ctx->cc_ic; 154 uint8_t *ivp; 155 int hdrlen; 156 157 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 158 159 /* 160 * Copy down 802.11 header and add the IV, KeyID, and ExtIV. 161 */ 162 M_PREPEND(m, ccmp.ic_header, MB_DONTWAIT); 163 if (m == NULL) 164 return 0; 165 ivp = mtod(m, uint8_t *); 166 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen); 167 ivp += hdrlen; 168 169 k->wk_keytsc++; /* XXX wrap at 48 bits */ 170 ivp[0] = k->wk_keytsc >> 0; /* PN0 */ 171 ivp[1] = k->wk_keytsc >> 8; /* PN1 */ 172 ivp[2] = 0; /* Reserved */ 173 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ 174 ivp[4] = k->wk_keytsc >> 16; /* PN2 */ 175 ivp[5] = k->wk_keytsc >> 24; /* PN3 */ 176 ivp[6] = k->wk_keytsc >> 32; /* PN4 */ 177 ivp[7] = k->wk_keytsc >> 40; /* PN5 */ 178 179 /* 180 * Finally, do software encrypt if neeed. 181 */ 182 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && 183 !ccmp_encrypt(k, m, hdrlen)) 184 return 0; 185 186 return 1; 187 } 188 189 static int 190 ccmp_getiv(struct ieee80211_key *k, struct ieee80211_crypto_iv *iv, 191 uint8_t keyid) 192 { 193 uint8_t *ivp = (uint8_t *)iv; 194 195 k->wk_keytsc++; /* XXX wrap at 48 bits */ 196 ivp[0] = k->wk_keytsc >> 0; /* PN0 */ 197 ivp[1] = k->wk_keytsc >> 8; /* PN1 */ 198 ivp[2] = 0; /* Reserved */ 199 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ 200 ivp[4] = k->wk_keytsc >> 16; /* PN2 */ 201 ivp[5] = k->wk_keytsc >> 24; /* PN3 */ 202 ivp[6] = k->wk_keytsc >> 32; /* PN4 */ 203 ivp[7] = k->wk_keytsc >> 40; /* PN5 */ 204 205 return 1; 206 } 207 208 /* 209 * Add MIC to the frame as needed. 210 */ 211 static int 212 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force) 213 { 214 return 1; 215 } 216 217 static __inline uint64_t 218 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) 219 { 220 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); 221 uint16_t iv16 = (b4 << 0) | (b5 << 8); 222 return (((uint64_t)iv16) << 32) | iv32; 223 } 224 225 /* 226 * Validate and strip privacy headers (and trailer) for a 227 * received frame. The specified key should be correct but 228 * is also verified. 229 */ 230 static int 231 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 232 { 233 struct ccmp_ctx *ctx = k->wk_private; 234 struct ieee80211_frame *wh; 235 uint8_t *ivp; 236 uint64_t pn; 237 238 /* 239 * Header should have extended IV and sequence number; 240 * verify the former and validate the latter. 241 */ 242 wh = mtod(m, struct ieee80211_frame *); 243 ivp = mtod(m, uint8_t *) + hdrlen; 244 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 245 /* 246 * No extended IV; discard frame. 247 */ 248 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 249 "[%6D] Missing ExtIV for AES-CCM cipher\n", 250 wh->i_addr2, ":"); 251 ctx->cc_ic->ic_stats.is_rx_ccmpformat++; 252 return 0; 253 } 254 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 255 if (pn <= k->wk_keyrsc) { 256 /* 257 * Replay violation. 258 */ 259 ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn); 260 ctx->cc_ic->ic_stats.is_rx_ccmpreplay++; 261 return 0; 262 } 263 264 /* 265 * Check if the device handled the decrypt in hardware. 266 * If so we just strip the header; otherwise we need to 267 * handle the decrypt in software. Note that for the 268 * latter we leave the header in place for use in the 269 * decryption work. 270 */ 271 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && 272 !ccmp_decrypt(k, pn, m, hdrlen)) 273 return 0; 274 275 /* 276 * Copy up 802.11 header and strip crypto bits. 277 */ 278 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, hdrlen); 279 m_adj(m, ccmp.ic_header); 280 m_adj(m, -ccmp.ic_trailer); 281 282 /* 283 * Ok to update rsc now. 284 */ 285 k->wk_keyrsc = pn; 286 287 return 1; 288 } 289 290 static int 291 ccmp_update(struct ieee80211_key *k, const struct ieee80211_crypto_iv *iv, 292 const struct ieee80211_frame *wh) 293 { 294 struct ccmp_ctx *ctx = k->wk_private; 295 const uint8_t *ivp = (const uint8_t *)iv; 296 uint64_t pn; 297 298 /* 299 * Header should have extended IV and sequence number; 300 * verify the former and validate the latter. 301 */ 302 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 303 /* 304 * No extended IV; discard frame. 305 */ 306 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 307 "[%6D] Missing ExtIV for AES-CCM cipher\n", 308 wh->i_addr2, ":"); 309 ctx->cc_ic->ic_stats.is_rx_ccmpformat++; 310 return 0; 311 } 312 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 313 if (pn <= k->wk_keyrsc) { 314 /* 315 * Replay violation. 316 */ 317 ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn); 318 ctx->cc_ic->ic_stats.is_rx_ccmpreplay++; 319 return 0; 320 } 321 322 /* 323 * Ok to update rsc now. 324 */ 325 k->wk_keyrsc = pn; 326 return 1; 327 } 328 329 /* 330 * Verify and strip MIC from the frame. 331 */ 332 static int 333 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force) 334 { 335 return 1; 336 } 337 338 static __inline void 339 xor_block(uint8_t *b, const uint8_t *a, size_t len) 340 { 341 int i; 342 for (i = 0; i < len; i++) 343 b[i] ^= a[i]; 344 } 345 346 /* 347 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 348 * 349 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> 350 * 351 * This program is free software; you can redistribute it and/or modify 352 * it under the terms of the GNU General Public License version 2 as 353 * published by the Free Software Foundation. See README and COPYING for 354 * more details. 355 * 356 * Alternatively, this software may be distributed under the terms of BSD 357 * license. 358 */ 359 360 static void 361 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, 362 uint64_t pn, size_t dlen, 363 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], 364 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) 365 { 366 #define IS_4ADDRESS(wh) \ 367 ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS) 368 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh) 369 370 /* CCM Initial Block: 371 * Flag (Include authentication header, M=3 (8-octet MIC), 372 * L=1 (2-octet Dlen)) 373 * Nonce: 0x00 | A2 | PN 374 * Dlen */ 375 b0[0] = 0x59; 376 /* NB: b0[1] set below */ 377 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); 378 b0[8] = pn >> 40; 379 b0[9] = pn >> 32; 380 b0[10] = pn >> 24; 381 b0[11] = pn >> 16; 382 b0[12] = pn >> 8; 383 b0[13] = pn >> 0; 384 b0[14] = (dlen >> 8) & 0xff; 385 b0[15] = dlen & 0xff; 386 387 /* AAD: 388 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one 389 * A1 | A2 | A3 390 * SC with bits 4..15 (seq#) masked to zero 391 * A4 (if present) 392 * QC (if present) 393 */ 394 aad[0] = 0; /* AAD length >> 8 */ 395 /* NB: aad[1] set below */ 396 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ 397 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ 398 /* NB: we know 3 addresses are contiguous */ 399 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); 400 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; 401 aad[23] = 0; /* all bits masked */ 402 /* 403 * Construct variable-length portion of AAD based 404 * on whether this is a 4-address frame/QOS frame. 405 * We always zero-pad to 32 bytes before running it 406 * through the cipher. 407 * 408 * We also fill in the priority bits of the CCM 409 * initial block as we know whether or not we have 410 * a QOS frame. 411 */ 412 if (IS_4ADDRESS(wh)) { 413 IEEE80211_ADDR_COPY(aad + 24, 414 ((struct ieee80211_frame_addr4 *)wh)->i_addr4); 415 if (IS_QOS_DATA(wh)) { 416 struct ieee80211_qosframe_addr4 *qwh4 = 417 (struct ieee80211_qosframe_addr4 *) wh; 418 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ 419 aad[31] = 0; 420 b0[1] = aad[30]; 421 aad[1] = 22 + IEEE80211_ADDR_LEN + 2; 422 } else { 423 *(uint16_t *)&aad[30] = 0; 424 b0[1] = 0; 425 aad[1] = 22 + IEEE80211_ADDR_LEN; 426 } 427 } else { 428 if (IS_QOS_DATA(wh)) { 429 struct ieee80211_qosframe *qwh = 430 (struct ieee80211_qosframe*) wh; 431 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ 432 aad[25] = 0; 433 b0[1] = aad[24]; 434 aad[1] = 22 + 2; 435 } else { 436 *(uint16_t *)&aad[24] = 0; 437 b0[1] = 0; 438 aad[1] = 22; 439 } 440 *(uint16_t *)&aad[26] = 0; 441 *(uint32_t *)&aad[28] = 0; 442 } 443 444 /* Start with the first block and AAD */ 445 rijndael_encrypt(ctx, b0, auth); 446 xor_block(auth, aad, AES_BLOCK_LEN); 447 rijndael_encrypt(ctx, auth, auth); 448 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 449 rijndael_encrypt(ctx, auth, auth); 450 b0[0] &= 0x07; 451 b0[14] = b0[15] = 0; 452 rijndael_encrypt(ctx, b0, s0); 453 #undef IS_QOS_DATA 454 #undef IS_4ADDRESS 455 } 456 457 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ 458 /* Authentication */ \ 459 xor_block(_b, _pos, _len); \ 460 rijndael_encrypt(&ctx->cc_aes, _b, _b); \ 461 /* Encryption, with counter */ \ 462 _b0[14] = (_i >> 8) & 0xff; \ 463 _b0[15] = _i & 0xff; \ 464 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ 465 xor_block(_pos, _e, _len); \ 466 } while (0) 467 468 static int 469 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 470 { 471 struct ccmp_ctx *ctx = key->wk_private; 472 struct ieee80211_frame *wh; 473 struct mbuf *m = m0; 474 int data_len, i, space; 475 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], 476 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; 477 uint8_t *pos; 478 479 ctx->cc_ic->ic_stats.is_crypto_ccmp++; 480 481 wh = mtod(m, struct ieee80211_frame *); 482 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); 483 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, 484 data_len, b0, aad, b, s0); 485 486 i = 1; 487 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 488 /* NB: assumes header is entirely in first mbuf */ 489 space = m->m_len - (hdrlen + ccmp.ic_header); 490 for (;;) { 491 if (space > data_len) 492 space = data_len; 493 /* 494 * Do full blocks. 495 */ 496 while (space >= AES_BLOCK_LEN) { 497 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); 498 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 499 data_len -= AES_BLOCK_LEN; 500 i++; 501 } 502 if (data_len <= 0) /* no more data */ 503 break; 504 m = m->m_next; 505 if (m == NULL) { /* last buffer */ 506 if (space != 0) { 507 /* 508 * Short last block. 509 */ 510 CCMP_ENCRYPT(i, b, b0, pos, e, space); 511 } 512 break; 513 } 514 if (space != 0) { 515 uint8_t *pos_next; 516 int space_next; 517 int len, dl, sp; 518 struct mbuf *n; 519 520 /* 521 * Block straddles one or more mbufs, gather data 522 * into the block buffer b, apply the cipher, then 523 * scatter the results back into the mbuf chain. 524 * The buffer will automatically get space bytes 525 * of data at offset 0 copied in+out by the 526 * CCMP_ENCRYPT request so we must take care of 527 * the remaining data. 528 */ 529 n = m; 530 dl = data_len; 531 sp = space; 532 for (;;) { 533 pos_next = mtod(n, uint8_t *); 534 len = min(dl, AES_BLOCK_LEN); 535 space_next = len > sp ? len - sp : 0; 536 if (n->m_len >= space_next) { 537 /* 538 * This mbuf has enough data; just grab 539 * what we need and stop. 540 */ 541 xor_block(b+sp, pos_next, space_next); 542 break; 543 } 544 /* 545 * This mbuf's contents are insufficient, 546 * take 'em all and prepare to advance to 547 * the next mbuf. 548 */ 549 xor_block(b+sp, pos_next, n->m_len); 550 sp += n->m_len, dl -= n->m_len; 551 n = n->m_next; 552 if (n == NULL) 553 break; 554 } 555 556 CCMP_ENCRYPT(i, b, b0, pos, e, space); 557 558 /* NB: just like above, but scatter data to mbufs */ 559 dl = data_len; 560 sp = space; 561 for (;;) { 562 pos_next = mtod(m, uint8_t *); 563 len = min(dl, AES_BLOCK_LEN); 564 space_next = len > sp ? len - sp : 0; 565 if (m->m_len >= space_next) { 566 xor_block(pos_next, e+sp, space_next); 567 break; 568 } 569 xor_block(pos_next, e+sp, m->m_len); 570 sp += m->m_len, dl -= m->m_len; 571 m = m->m_next; 572 if (m == NULL) 573 goto done; 574 } 575 /* 576 * Do bookkeeping. m now points to the last mbuf 577 * we grabbed data from. We know we consumed a 578 * full block of data as otherwise we'd have hit 579 * the end of the mbuf chain, so deduct from data_len. 580 * Otherwise advance the block number (i) and setup 581 * pos+space to reflect contents of the new mbuf. 582 */ 583 data_len -= AES_BLOCK_LEN; 584 i++; 585 pos = pos_next + space_next; 586 space = m->m_len - space_next; 587 } else { 588 /* 589 * Setup for next buffer. 590 */ 591 pos = mtod(m, uint8_t *); 592 space = m->m_len; 593 } 594 } 595 done: 596 /* tack on MIC */ 597 xor_block(b, s0, ccmp.ic_trailer); 598 return ieee80211_mbuf_append(m0, ccmp.ic_trailer, b); 599 } 600 #undef CCMP_ENCRYPT 601 602 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ 603 /* Decrypt, with counter */ \ 604 _b0[14] = (_i >> 8) & 0xff; \ 605 _b0[15] = _i & 0xff; \ 606 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ 607 xor_block(_pos, _b, _len); \ 608 /* Authentication */ \ 609 xor_block(_a, _pos, _len); \ 610 rijndael_encrypt(&ctx->cc_aes, _a, _a); \ 611 } while (0) 612 613 static int 614 ccmp_decrypt(struct ieee80211_key *key, uint64_t pn, struct mbuf *m, int hdrlen) 615 { 616 struct ccmp_ctx *ctx = key->wk_private; 617 struct ieee80211_frame *wh; 618 uint8_t aad[2 * AES_BLOCK_LEN]; 619 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; 620 uint8_t mic[AES_BLOCK_LEN]; 621 size_t data_len; 622 int i; 623 uint8_t *pos; 624 u_int space; 625 626 ctx->cc_ic->ic_stats.is_crypto_ccmp++; 627 628 wh = mtod(m, struct ieee80211_frame *); 629 data_len = m->m_pkthdr.len - 630 (hdrlen + ccmp.ic_header + ccmp.ic_trailer); 631 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b); 632 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, 633 (caddr_t)mic); 634 xor_block(mic, b, ccmp.ic_trailer); 635 636 i = 1; 637 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; 638 space = m->m_len - (hdrlen + ccmp.ic_header); 639 for (;;) { 640 if (space > data_len) 641 space = data_len; 642 while (space >= AES_BLOCK_LEN) { 643 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); 644 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 645 data_len -= AES_BLOCK_LEN; 646 i++; 647 } 648 if (data_len <= 0) /* no more data */ 649 break; 650 m = m->m_next; 651 if (m == NULL) { /* last buffer */ 652 if (space != 0) /* short last block */ 653 CCMP_DECRYPT(i, b, b0, pos, a, space); 654 break; 655 } 656 if (space != 0) { 657 uint8_t *pos_next; 658 u_int space_next; 659 u_int len; 660 661 /* 662 * Block straddles buffers, split references. We 663 * do not handle splits that require >2 buffers 664 * since rx'd frames are never badly fragmented 665 * because drivers typically recv in clusters. 666 */ 667 pos_next = mtod(m, uint8_t *); 668 len = min(data_len, AES_BLOCK_LEN); 669 space_next = len > space ? len - space : 0; 670 KASSERT(m->m_len >= space_next, 671 ("not enough data in following buffer, " 672 "m_len %u need %u\n", m->m_len, space_next)); 673 674 xor_block(b+space, pos_next, space_next); 675 CCMP_DECRYPT(i, b, b0, pos, a, space); 676 xor_block(pos_next, b+space, space_next); 677 data_len -= len; 678 i++; 679 680 pos = pos_next + space_next; 681 space = m->m_len - space_next; 682 } else { 683 /* 684 * Setup for next buffer. 685 */ 686 pos = mtod(m, uint8_t *); 687 space = m->m_len; 688 } 689 } 690 if (memcmp(mic, a, ccmp.ic_trailer) != 0) { 691 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 692 "[%6D] AES-CCM decrypt failed; MIC mismatch\n", 693 wh->i_addr2, ":"); 694 ctx->cc_ic->ic_stats.is_rx_ccmpmic++; 695 return 0; 696 } 697 return 1; 698 } 699 #undef CCMP_DECRYPT 700 701 /* 702 * Module glue. 703 */ 704 static int 705 ccmp_modevent(module_t mod, int type, void *unused) 706 { 707 switch (type) { 708 case MOD_LOAD: 709 ieee80211_crypto_register(&ccmp); 710 return 0; 711 case MOD_UNLOAD: 712 if (nrefs) { 713 kprintf("wlan_ccmp: still in use (%u dynamic refs)\n", 714 nrefs); 715 return EBUSY; 716 } 717 ieee80211_crypto_unregister(&ccmp); 718 return 0; 719 } 720 return EINVAL; 721 } 722 723 static moduledata_t ccmp_mod = { 724 "wlan_ccmp", 725 ccmp_modevent, 726 0 727 }; 728 DECLARE_MODULE(wlan_ccmp, ccmp_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 729 MODULE_VERSION(wlan_ccmp, 1); 730 MODULE_DEPEND(wlan_ccmp, wlan, 1, 1, 1); 731