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 #define CCMP_128_MIC_LEN 8 58 #define CCMP_256_MIC_LEN 16 59 60 struct ccmp_ctx { 61 struct ieee80211vap *cc_vap; /* for diagnostics+statistics */ 62 struct ieee80211com *cc_ic; 63 rijndael_ctx cc_aes; 64 }; 65 66 static void *ccmp_attach(struct ieee80211vap *, struct ieee80211_key *); 67 static void ccmp_detach(struct ieee80211_key *); 68 static int ccmp_setkey(struct ieee80211_key *); 69 static void ccmp_setiv(struct ieee80211_key *, uint8_t *); 70 static int ccmp_encap(struct ieee80211_key *, struct mbuf *); 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 75 static const struct ieee80211_cipher ccmp = { 76 .ic_name = "AES-CCM", 77 .ic_cipher = IEEE80211_CIPHER_AES_CCM, 78 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + 79 IEEE80211_WEP_EXTIVLEN, 80 .ic_trailer = CCMP_128_MIC_LEN, 81 .ic_miclen = 0, 82 .ic_attach = ccmp_attach, 83 .ic_detach = ccmp_detach, 84 .ic_setkey = ccmp_setkey, 85 .ic_setiv = ccmp_setiv, 86 .ic_encap = ccmp_encap, 87 .ic_decap = ccmp_decap, 88 .ic_enmic = ccmp_enmic, 89 .ic_demic = ccmp_demic, 90 }; 91 92 static const struct ieee80211_cipher ccmp_256 = { 93 .ic_name = "AES-CCM-256", 94 .ic_cipher = IEEE80211_CIPHER_AES_CCM_256, 95 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + 96 IEEE80211_WEP_EXTIVLEN, 97 .ic_trailer = CCMP_256_MIC_LEN, 98 .ic_miclen = 0, 99 .ic_attach = ccmp_attach, 100 .ic_detach = ccmp_detach, 101 .ic_setkey = ccmp_setkey, 102 .ic_setiv = ccmp_setiv, 103 .ic_encap = ccmp_encap, 104 .ic_decap = ccmp_decap, 105 .ic_enmic = ccmp_enmic, 106 .ic_demic = ccmp_demic, 107 }; 108 109 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 110 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, 111 struct mbuf *, int hdrlen); 112 113 /* number of references from net80211 layer */ 114 static int nrefs = 0; 115 116 static void * 117 ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k) 118 { 119 struct ccmp_ctx *ctx; 120 121 ctx = (struct ccmp_ctx *) IEEE80211_MALLOC(sizeof(struct ccmp_ctx), 122 M_80211_CRYPTO, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 123 if (ctx == NULL) { 124 vap->iv_stats.is_crypto_nomem++; 125 return NULL; 126 } 127 ctx->cc_vap = vap; 128 ctx->cc_ic = vap->iv_ic; 129 nrefs++; /* NB: we assume caller locking */ 130 return ctx; 131 } 132 133 static void 134 ccmp_detach(struct ieee80211_key *k) 135 { 136 struct ccmp_ctx *ctx = k->wk_private; 137 138 IEEE80211_FREE(ctx, M_80211_CRYPTO); 139 KASSERT(nrefs > 0, ("imbalanced attach/detach")); 140 nrefs--; /* NB: we assume caller locking */ 141 } 142 143 static int 144 ccmp_get_trailer_len(struct ieee80211_key *k) 145 { 146 return (k->wk_cipher->ic_trailer); 147 } 148 149 static int 150 ccmp_get_header_len(struct ieee80211_key *k) 151 { 152 return (k->wk_cipher->ic_header); 153 } 154 155 /** 156 * @brief Return the M parameter to use for CCMP block0 initialisation. 157 * 158 * M is defined as the number of bytes in the authentication 159 * field. 160 * 161 * See RFC3610, Section 2 (CCM Mode Specification) for more 162 * information. 163 * 164 * The MIC size is defined in 802.11-2020 12.5.3 165 * (CTR with CBC-MAC Protocol (CCMP)). 166 * 167 * CCM-128 - M=8, MIC is 8 octets. 168 * CCM-256 - M=16, MIC is 16 octets. 169 * 170 * @param key ieee80211_key to calculate M for 171 * @retval the number of bytes in the authentication field 172 */ 173 static int 174 ccmp_get_ccm_m(struct ieee80211_key *k) 175 { 176 if (k->wk_cipher->ic_cipher == IEEE80211_CIPHER_AES_CCM) 177 return (8); 178 if (k->wk_cipher->ic_cipher == IEEE80211_CIPHER_AES_CCM_256) 179 return (16); 180 return (8); /* XXX default */ 181 } 182 183 static int 184 ccmp_setkey(struct ieee80211_key *k) 185 { 186 uint32_t keylen; 187 struct ccmp_ctx *ctx = k->wk_private; 188 189 switch (k->wk_cipher->ic_cipher) { 190 case IEEE80211_CIPHER_AES_CCM: 191 keylen = 128; 192 break; 193 case IEEE80211_CIPHER_AES_CCM_256: 194 keylen = 256; 195 break; 196 default: 197 IEEE80211_DPRINTF(ctx->cc_vap, IEEE80211_MSG_CRYPTO, 198 "%s: Unexpected cipher (%u)", 199 __func__, k->wk_cipher->ic_cipher); 200 return (0); 201 } 202 203 if (k->wk_keylen != (keylen/NBBY)) { 204 IEEE80211_DPRINTF(ctx->cc_vap, IEEE80211_MSG_CRYPTO, 205 "%s: Invalid key length %u, expecting %u\n", 206 __func__, k->wk_keylen, keylen/NBBY); 207 return 0; 208 } 209 if (k->wk_flags & IEEE80211_KEY_SWENCRYPT) 210 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY); 211 return 1; 212 } 213 214 static void 215 ccmp_setiv(struct ieee80211_key *k, uint8_t *ivp) 216 { 217 struct ccmp_ctx *ctx = k->wk_private; 218 struct ieee80211vap *vap = ctx->cc_vap; 219 uint8_t keyid; 220 221 keyid = ieee80211_crypto_get_keyid(vap, k) << 6; 222 223 k->wk_keytsc++; 224 ivp[0] = k->wk_keytsc >> 0; /* PN0 */ 225 ivp[1] = k->wk_keytsc >> 8; /* PN1 */ 226 ivp[2] = 0; /* Reserved */ 227 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ 228 ivp[4] = k->wk_keytsc >> 16; /* PN2 */ 229 ivp[5] = k->wk_keytsc >> 24; /* PN3 */ 230 ivp[6] = k->wk_keytsc >> 32; /* PN4 */ 231 ivp[7] = k->wk_keytsc >> 40; /* PN5 */ 232 } 233 234 /* 235 * Add privacy headers appropriate for the specified key. 236 */ 237 static int 238 ccmp_encap(struct ieee80211_key *k, struct mbuf *m) 239 { 240 const struct ieee80211_frame *wh; 241 struct ccmp_ctx *ctx = k->wk_private; 242 struct ieee80211com *ic = ctx->cc_ic; 243 uint8_t *ivp; 244 int hdrlen; 245 int is_mgmt; 246 247 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 248 wh = mtod(m, const struct ieee80211_frame *); 249 is_mgmt = IEEE80211_IS_MGMT(wh); 250 251 /* 252 * Check to see if we need to insert IV/MIC. 253 * 254 * Some offload devices don't require the IV to be inserted 255 * as part of the hardware encryption. 256 */ 257 if (is_mgmt && (k->wk_flags & IEEE80211_KEY_NOIVMGT)) 258 return 1; 259 if ((! is_mgmt) && (k->wk_flags & IEEE80211_KEY_NOIV)) 260 return 1; 261 262 /* 263 * Copy down 802.11 header and add the IV, KeyID, and ExtIV. 264 */ 265 M_PREPEND(m, ccmp_get_header_len(k), IEEE80211_M_NOWAIT); 266 if (m == NULL) 267 return 0; 268 ivp = mtod(m, uint8_t *); 269 ovbcopy(ivp + ccmp_get_header_len(k), ivp, hdrlen); 270 ivp += hdrlen; 271 272 ccmp_setiv(k, ivp); 273 274 /* 275 * Finally, do software encrypt if needed. 276 */ 277 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) && 278 !ccmp_encrypt(k, m, hdrlen)) 279 return 0; 280 281 return 1; 282 } 283 284 /* 285 * Add MIC to the frame as needed. 286 */ 287 static int 288 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force) 289 { 290 291 return 1; 292 } 293 294 static __inline uint64_t 295 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) 296 { 297 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); 298 uint16_t iv16 = (b4 << 0) | (b5 << 8); 299 return (((uint64_t)iv16) << 32) | iv32; 300 } 301 302 /* 303 * Validate and strip privacy headers (and trailer) for a 304 * received frame. The specified key should be correct but 305 * is also verified. 306 */ 307 static int 308 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 309 { 310 const struct ieee80211_rx_stats *rxs; 311 struct ccmp_ctx *ctx = k->wk_private; 312 struct ieee80211vap *vap = ctx->cc_vap; 313 struct ieee80211_frame *wh; 314 uint8_t *ivp, tid; 315 uint64_t pn; 316 bool noreplaycheck; 317 318 rxs = ieee80211_get_rx_params_ptr(m); 319 320 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) != 0) 321 goto finish; 322 323 /* 324 * Header should have extended IV and sequence number; 325 * verify the former and validate the latter. 326 */ 327 wh = mtod(m, struct ieee80211_frame *); 328 ivp = mtod(m, uint8_t *) + hdrlen; 329 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 330 /* 331 * No extended IV; discard frame. 332 */ 333 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 334 "%s", "missing ExtIV for AES-CCM cipher"); 335 vap->iv_stats.is_rx_ccmpformat++; 336 return 0; 337 } 338 tid = ieee80211_gettid(wh); 339 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 340 341 noreplaycheck = (k->wk_flags & IEEE80211_KEY_NOREPLAY) != 0; 342 noreplaycheck |= (rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_PN_VALIDATED) != 0; 343 if (pn <= k->wk_keyrsc[tid] && !noreplaycheck) { 344 /* 345 * Replay violation. 346 */ 347 ieee80211_notify_replay_failure(vap, wh, k, pn, tid); 348 vap->iv_stats.is_rx_ccmpreplay++; 349 return 0; 350 } 351 352 /* 353 * Check if the device handled the decrypt in hardware. 354 * If so we just strip the header; otherwise we need to 355 * handle the decrypt in software. Note that for the 356 * latter we leave the header in place for use in the 357 * decryption work. 358 */ 359 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) && 360 !ccmp_decrypt(k, pn, m, hdrlen)) 361 return 0; 362 363 finish: 364 /* 365 * Copy up 802.11 header and strip crypto bits. 366 */ 367 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) { 368 ovbcopy(mtod(m, void *), 369 mtod(m, uint8_t *) + ccmp_get_header_len(k), 370 hdrlen); 371 m_adj(m, ccmp_get_header_len(k)); 372 } 373 374 if ((rxs == NULL) || (rxs->c_pktflags & IEEE80211_RX_F_MIC_STRIP) == 0) 375 m_adj(m, -ccmp_get_trailer_len(k)); 376 377 /* 378 * Ok to update rsc now. 379 */ 380 if ((rxs == NULL) || (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) == 0) { 381 /* 382 * Do not go backwards in the IEEE80211_KEY_NOREPLAY cases 383 * or in case hardware has checked but frames are arriving 384 * reordered (e.g., LinuxKPI drivers doing RSS which we are 385 * not prepared for at all). 386 */ 387 if (pn > k->wk_keyrsc[tid]) 388 k->wk_keyrsc[tid] = pn; 389 } 390 391 return 1; 392 } 393 394 /* 395 * Verify and strip MIC from the frame. 396 */ 397 static int 398 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force) 399 { 400 return 1; 401 } 402 403 static __inline void 404 xor_block(uint8_t *b, const uint8_t *a, size_t len) 405 { 406 int i; 407 for (i = 0; i < len; i++) 408 b[i] ^= a[i]; 409 } 410 411 /** 412 * @brief Initialise the AES-CCM nonce flag field in the b0 CCMP block. 413 * 414 * The B_0 block is defined in RFC 3610 section 2.2 (Authentication). 415 * b0[0] is the CCM flags field, so the nonce used for B_0 starts at 416 * b0[1]. Amusingly, b0[1] is also flags, but it's the 802.11 AES-CCM 417 * nonce flags field, NOT the CCM flags field. 418 * 419 * The AES-CCM nonce flags field is defined in 802.11-2020 12.5.3.3.4 420 * (Construct CCM nonce). 421 * 422 * TODO: net80211 currently doesn't support MFP (management frame protection) 423 * and so bit 4 is never set. This routine and ccmp_init_blocks() will 424 * need a pointer to the ieee80211_node or a flag that explicitly states 425 * the frame will be sent w/ MFP encryption / received w/ MFP decryption. 426 * 427 * @param wh the 802.11 header to populate 428 * @param b0 the CCM nonce to update (remembering b0[0] is the CCM 429 * nonce flags, and b0[1] is the AES-CCM nonce flags). 430 */ 431 static void 432 ieee80211_crypto_ccmp_init_nonce_flags(const struct ieee80211_frame *wh, 433 char *b0) 434 { 435 if (IEEE80211_IS_DSTODS(wh)) { 436 /* 437 * 802.11-2020 12.5.33.3.4 (Construct CCM nonce) mentions 438 * that the low four bits of this byte are the "MPDU priority." 439 * This is defined in 5.1.1.2 (Determination of UP) and 440 * 5.1.1.3 (Interpretation of Priority Parameter in MAC 441 * service primitives). 442 * 443 * The former says "The QoS facility supports eight priority 444 * values, referred to as UPs. The values a UP may take are 445 * the integer values from 0 to 7 and are identical to the 446 * 802.11D priority tags." 447 * 448 * The latter specifically calls out that "Priority parameter 449 * and TID subfield values 0 to 7 are interpreted aas UPs for 450 * the MSDUs" .. and " .. TID subfield values 8 to 15 specify 451 * TIDs that are TS identifiers (TSIDs)" which are used for 452 * TSPEC. There's a bunch of extra work to be done with frames 453 * received in TIDs 8..15 with no TSPEC, "then the MSDU shall 454 * be sent with priority parameter set to 0." 455 * 456 * All QoS frames (not just QoS data) have TID fields and 457 * thus priorities. However, the code straight up 458 * copies the 4 bit TID field, rather than a 3 bit MPDU 459 * priority value. For now, as net80211 doesn't specifically 460 * support TSPEC negotiation, this likely never gets checked. 461 * However as part of any future TSPEC work, this will likely 462 * need to be looked at and checked with interoperability 463 * with other stacks. 464 */ 465 if (IEEE80211_IS_QOS_ANY(wh)) { 466 const struct ieee80211_qosframe_addr4 *qwh4 = 467 (const struct ieee80211_qosframe_addr4 *) wh; 468 b0[1] = qwh4->i_qos[0] & 0x0f; /* prio bits */ 469 } else { 470 b0[1] = 0; 471 } 472 } else { 473 if (IEEE80211_IS_QOS_ANY(wh)) { 474 const struct ieee80211_qosframe *qwh = 475 (const struct ieee80211_qosframe *) wh; 476 b0[1] = qwh->i_qos[0] & 0x0f; /* prio bits */ 477 } else { 478 b0[1] = 0; 479 } 480 } 481 /* TODO: populate MFP flag */ 482 } 483 484 /* 485 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 486 * 487 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> 488 * 489 * This program is free software; you can redistribute it and/or modify 490 * it under the terms of the GNU General Public License version 2 as 491 * published by the Free Software Foundation. See README and COPYING for 492 * more details. 493 * 494 * Alternatively, this software may be distributed under the terms of BSD 495 * license. 496 */ 497 498 static void 499 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, 500 uint32_t m, u_int64_t pn, size_t dlen, 501 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], 502 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) 503 { 504 /* 505 * Map M parameter to encoding 506 * RFC3610, Section 2 (CCM Mode Specification) 507 */ 508 m = (m - 2) / 2; 509 510 /* CCM Initial Block: 511 * 512 * Flag (Include authentication header, 513 * M=3 or 7 (8 or 16 octet auth field), 514 * L=1 (2-octet Dlen)) 515 * Adata=1 (one or more auth blocks present) 516 * Nonce: 0x00 | A2 | PN 517 * Dlen 518 */ 519 b0[0] = 0x40 | 0x01 | (m << 3); 520 /* Init b0[1] (CCM nonce flags) */ 521 ieee80211_crypto_ccmp_init_nonce_flags(wh, b0); 522 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); 523 b0[8] = pn >> 40; 524 b0[9] = pn >> 32; 525 b0[10] = pn >> 24; 526 b0[11] = pn >> 16; 527 b0[12] = pn >> 8; 528 b0[13] = pn >> 0; 529 b0[14] = (dlen >> 8) & 0xff; 530 b0[15] = dlen & 0xff; 531 532 /* Init AAD */ 533 (void) ieee80211_crypto_init_aad(wh, aad, 2 * AES_BLOCK_LEN); 534 535 /* Start with the first block and AAD */ 536 rijndael_encrypt(ctx, b0, auth); 537 xor_block(auth, aad, AES_BLOCK_LEN); 538 rijndael_encrypt(ctx, auth, auth); 539 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); 540 rijndael_encrypt(ctx, auth, auth); 541 b0[0] &= 0x07; 542 b0[14] = b0[15] = 0; 543 rijndael_encrypt(ctx, b0, s0); 544 } 545 546 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ 547 /* Authentication */ \ 548 xor_block(_b, _pos, _len); \ 549 rijndael_encrypt(&ctx->cc_aes, _b, _b); \ 550 /* Encryption, with counter */ \ 551 _b0[14] = (_i >> 8) & 0xff; \ 552 _b0[15] = _i & 0xff; \ 553 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ 554 xor_block(_pos, _e, _len); \ 555 } while (0) 556 557 static int 558 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) 559 { 560 struct ccmp_ctx *ctx = key->wk_private; 561 struct ieee80211_frame *wh; 562 struct mbuf *m = m0; 563 int data_len, i, space; 564 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], 565 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; 566 uint8_t *pos; 567 568 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 569 570 wh = mtod(m, struct ieee80211_frame *); 571 data_len = m->m_pkthdr.len - (hdrlen + ccmp_get_header_len(key)); 572 ccmp_init_blocks(&ctx->cc_aes, wh, ccmp_get_ccm_m(key), 573 key->wk_keytsc, data_len, b0, aad, b, s0); 574 575 i = 1; 576 pos = mtod(m, uint8_t *) + hdrlen + ccmp_get_header_len(key); 577 /* NB: assumes header is entirely in first mbuf */ 578 space = m->m_len - (hdrlen + ccmp_get_header_len(key)); 579 for (;;) { 580 if (space > data_len) 581 space = data_len; 582 /* 583 * Do full blocks. 584 */ 585 while (space >= AES_BLOCK_LEN) { 586 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); 587 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 588 data_len -= AES_BLOCK_LEN; 589 i++; 590 } 591 if (data_len <= 0) /* no more data */ 592 break; 593 m = m->m_next; 594 if (m == NULL) { /* last buffer */ 595 if (space != 0) { 596 /* 597 * Short last block. 598 */ 599 CCMP_ENCRYPT(i, b, b0, pos, e, space); 600 } 601 break; 602 } 603 if (space != 0) { 604 uint8_t *pos_next; 605 int space_next; 606 int len, dl, sp; 607 struct mbuf *n; 608 609 /* 610 * Block straddles one or more mbufs, gather data 611 * into the block buffer b, apply the cipher, then 612 * scatter the results back into the mbuf chain. 613 * The buffer will automatically get space bytes 614 * of data at offset 0 copied in+out by the 615 * CCMP_ENCRYPT request so we must take care of 616 * the remaining data. 617 */ 618 n = m; 619 dl = data_len; 620 sp = space; 621 for (;;) { 622 pos_next = mtod(n, uint8_t *); 623 len = min(dl, AES_BLOCK_LEN); 624 space_next = len > sp ? len - sp : 0; 625 if (n->m_len >= space_next) { 626 /* 627 * This mbuf has enough data; just grab 628 * what we need and stop. 629 */ 630 xor_block(b+sp, pos_next, space_next); 631 break; 632 } 633 /* 634 * This mbuf's contents are insufficient, 635 * take 'em all and prepare to advance to 636 * the next mbuf. 637 */ 638 xor_block(b+sp, pos_next, n->m_len); 639 sp += n->m_len, dl -= n->m_len; 640 n = n->m_next; 641 if (n == NULL) 642 break; 643 } 644 645 CCMP_ENCRYPT(i, b, b0, pos, e, space); 646 647 /* NB: just like above, but scatter data to mbufs */ 648 dl = data_len; 649 sp = space; 650 for (;;) { 651 pos_next = mtod(m, uint8_t *); 652 len = min(dl, AES_BLOCK_LEN); 653 space_next = len > sp ? len - sp : 0; 654 if (m->m_len >= space_next) { 655 xor_block(pos_next, e+sp, space_next); 656 break; 657 } 658 xor_block(pos_next, e+sp, m->m_len); 659 sp += m->m_len, dl -= m->m_len; 660 m = m->m_next; 661 if (m == NULL) 662 goto done; 663 } 664 /* 665 * Do bookkeeping. m now points to the last mbuf 666 * we grabbed data from. We know we consumed a 667 * full block of data as otherwise we'd have hit 668 * the end of the mbuf chain, so deduct from data_len. 669 * Otherwise advance the block number (i) and setup 670 * pos+space to reflect contents of the new mbuf. 671 */ 672 data_len -= AES_BLOCK_LEN; 673 i++; 674 pos = pos_next + space_next; 675 space = m->m_len - space_next; 676 } else { 677 /* 678 * Setup for next buffer. 679 */ 680 pos = mtod(m, uint8_t *); 681 space = m->m_len; 682 } 683 } 684 done: 685 /* tack on MIC */ 686 xor_block(b, s0, ccmp_get_trailer_len(key)); 687 return m_append(m0, ccmp_get_trailer_len(key), b); 688 } 689 #undef CCMP_ENCRYPT 690 691 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ 692 /* Decrypt, with counter */ \ 693 _b0[14] = (_i >> 8) & 0xff; \ 694 _b0[15] = _i & 0xff; \ 695 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ 696 xor_block(_pos, _b, _len); \ 697 /* Authentication */ \ 698 xor_block(_a, _pos, _len); \ 699 rijndael_encrypt(&ctx->cc_aes, _a, _a); \ 700 } while (0) 701 702 static int 703 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen) 704 { 705 const struct ieee80211_rx_stats *rxs; 706 struct ccmp_ctx *ctx = key->wk_private; 707 struct ieee80211vap *vap = ctx->cc_vap; 708 struct ieee80211_frame *wh; 709 uint8_t aad[2 * AES_BLOCK_LEN]; 710 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; 711 uint8_t mic[AES_BLOCK_LEN]; 712 size_t data_len; 713 int i; 714 uint8_t *pos; 715 u_int space; 716 717 rxs = ieee80211_get_rx_params_ptr(m); 718 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED) != 0) 719 return (1); 720 721 ctx->cc_vap->iv_stats.is_crypto_ccmp++; 722 723 wh = mtod(m, struct ieee80211_frame *); 724 data_len = m->m_pkthdr.len - 725 (hdrlen + ccmp_get_header_len(key) + ccmp_get_trailer_len(key)); 726 ccmp_init_blocks(&ctx->cc_aes, wh, ccmp_get_ccm_m(key), pn, 727 data_len, b0, aad, a, b); 728 m_copydata(m, m->m_pkthdr.len - ccmp_get_trailer_len(key), 729 ccmp_get_trailer_len(key), mic); 730 xor_block(mic, b, ccmp_get_trailer_len(key)); 731 732 i = 1; 733 pos = mtod(m, uint8_t *) + hdrlen + ccmp_get_header_len(key); 734 space = m->m_len - (hdrlen + ccmp_get_header_len(key)); 735 for (;;) { 736 if (space > data_len) 737 space = data_len; 738 while (space >= AES_BLOCK_LEN) { 739 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); 740 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; 741 data_len -= AES_BLOCK_LEN; 742 i++; 743 } 744 if (data_len <= 0) /* no more data */ 745 break; 746 m = m->m_next; 747 if (m == NULL) { /* last buffer */ 748 if (space != 0) /* short last block */ 749 CCMP_DECRYPT(i, b, b0, pos, a, space); 750 break; 751 } 752 if (space != 0) { 753 uint8_t *pos_next; 754 u_int space_next; 755 u_int len; 756 757 /* 758 * Block straddles buffers, split references. We 759 * do not handle splits that require >2 buffers 760 * since rx'd frames are never badly fragmented 761 * because drivers typically recv in clusters. 762 */ 763 pos_next = mtod(m, uint8_t *); 764 len = min(data_len, AES_BLOCK_LEN); 765 space_next = len > space ? len - space : 0; 766 KASSERT(m->m_len >= space_next, 767 ("not enough data in following buffer, " 768 "m_len %u need %u\n", m->m_len, space_next)); 769 770 xor_block(b+space, pos_next, space_next); 771 CCMP_DECRYPT(i, b, b0, pos, a, space); 772 xor_block(pos_next, b+space, space_next); 773 data_len -= len; 774 i++; 775 776 pos = pos_next + space_next; 777 space = m->m_len - space_next; 778 } else { 779 /* 780 * Setup for next buffer. 781 */ 782 pos = mtod(m, uint8_t *); 783 space = m->m_len; 784 } 785 } 786 787 /* 788 * If the MIC was stripped by HW/driver we are done. 789 */ 790 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_MIC_STRIP) != 0) 791 return (1); 792 793 if (memcmp(mic, a, ccmp_get_trailer_len(key)) != 0) { 794 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 795 "%s", "AES-CCM decrypt failed; MIC mismatch"); 796 vap->iv_stats.is_rx_ccmpmic++; 797 return 0; 798 } 799 return 1; 800 } 801 #undef CCMP_DECRYPT 802 803 /* 804 * Module glue. 805 */ 806 IEEE80211_CRYPTO_MODULE(ccmp, 1); 807 IEEE80211_CRYPTO_MODULE_ADD(ccmp_256); 808