1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2001 Atsushi Onoe 5 * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 /* 31 * IEEE 802.11 generic crypto support. 32 */ 33 #include "opt_wlan.h" 34 35 #include <sys/param.h> 36 #include <sys/kernel.h> 37 #include <sys/malloc.h> 38 #include <sys/mbuf.h> 39 40 #include <sys/socket.h> 41 42 #include <net/if.h> 43 #include <net/if_media.h> 44 #include <net/ethernet.h> /* XXX ETHER_HDR_LEN */ 45 46 #include <net80211/ieee80211_var.h> 47 48 MALLOC_DEFINE(M_80211_CRYPTO, "80211crypto", "802.11 crypto state"); 49 50 static int _ieee80211_crypto_delkey(struct ieee80211vap *, 51 struct ieee80211_key *); 52 53 /* 54 * Table of registered cipher modules. 55 */ 56 static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX]; 57 58 /* 59 * Default "null" key management routines. 60 */ 61 static int 62 null_key_alloc(struct ieee80211vap *vap, struct ieee80211_key *k, 63 ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix) 64 { 65 if (!(&vap->iv_nw_keys[0] <= k && 66 k < &vap->iv_nw_keys[IEEE80211_WEP_NKID])) { 67 /* 68 * Not in the global key table, the driver should handle this 69 * by allocating a slot in the h/w key table/cache. In 70 * lieu of that return key slot 0 for any unicast key 71 * request. We disallow the request if this is a group key. 72 * This default policy does the right thing for legacy hardware 73 * with a 4 key table. It also handles devices that pass 74 * packets through untouched when marked with the WEP bit 75 * and key index 0. 76 */ 77 if (k->wk_flags & IEEE80211_KEY_GROUP) 78 return 0; 79 *keyix = 0; /* NB: use key index 0 for ucast key */ 80 } else { 81 *keyix = ieee80211_crypto_get_key_wepidx(vap, k); 82 } 83 *rxkeyix = IEEE80211_KEYIX_NONE; /* XXX maybe *keyix? */ 84 return 1; 85 } 86 static int 87 null_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k) 88 { 89 return 1; 90 } 91 static int 92 null_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k) 93 { 94 return 1; 95 } 96 static void null_key_update(struct ieee80211vap *vap) {} 97 98 /* 99 * Write-arounds for common operations. 100 */ 101 static __inline void 102 cipher_detach(struct ieee80211_key *key) 103 { 104 key->wk_cipher->ic_detach(key); 105 } 106 107 static __inline void * 108 cipher_attach(struct ieee80211vap *vap, struct ieee80211_key *key) 109 { 110 return key->wk_cipher->ic_attach(vap, key); 111 } 112 113 /* 114 * Wrappers for driver key management methods. 115 */ 116 static __inline int 117 dev_key_alloc(struct ieee80211vap *vap, 118 struct ieee80211_key *key, 119 ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix) 120 { 121 return vap->iv_key_alloc(vap, key, keyix, rxkeyix); 122 } 123 124 static __inline int 125 dev_key_delete(struct ieee80211vap *vap, 126 const struct ieee80211_key *key) 127 { 128 return vap->iv_key_delete(vap, key); 129 } 130 131 static __inline int 132 dev_key_set(struct ieee80211vap *vap, const struct ieee80211_key *key) 133 { 134 return vap->iv_key_set(vap, key); 135 } 136 137 /* 138 * Setup crypto support for a device/shared instance. 139 */ 140 void 141 ieee80211_crypto_attach(struct ieee80211com *ic) 142 { 143 /* NB: we assume everything is pre-zero'd */ 144 ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none; 145 146 /* 147 * Default set of net80211 supported ciphers. 148 * 149 * These are the default set that all drivers are expected to 150 * support, either/or in hardware and software. 151 * 152 * Drivers can add their own support to this and the 153 * hardware cipher list (ic_cryptocaps.) 154 */ 155 ic->ic_sw_cryptocaps = IEEE80211_CRYPTO_WEP | 156 IEEE80211_CRYPTO_TKIP | IEEE80211_CRYPTO_AES_CCM; 157 } 158 159 /* 160 * Teardown crypto support. 161 */ 162 void 163 ieee80211_crypto_detach(struct ieee80211com *ic) 164 { 165 } 166 167 /* 168 * Setup crypto support for a vap. 169 */ 170 void 171 ieee80211_crypto_vattach(struct ieee80211vap *vap) 172 { 173 int i; 174 175 /* NB: we assume everything is pre-zero'd */ 176 vap->iv_max_keyix = IEEE80211_WEP_NKID; 177 vap->iv_def_txkey = IEEE80211_KEYIX_NONE; 178 for (i = 0; i < IEEE80211_WEP_NKID; i++) 179 ieee80211_crypto_resetkey(vap, &vap->iv_nw_keys[i], 180 IEEE80211_KEYIX_NONE); 181 /* 182 * Initialize the driver key support routines to noop entries. 183 * This is useful especially for the cipher test modules. 184 */ 185 vap->iv_key_alloc = null_key_alloc; 186 vap->iv_key_set = null_key_set; 187 vap->iv_key_delete = null_key_delete; 188 vap->iv_key_update_begin = null_key_update; 189 vap->iv_key_update_end = null_key_update; 190 } 191 192 /* 193 * Teardown crypto support for a vap. 194 */ 195 void 196 ieee80211_crypto_vdetach(struct ieee80211vap *vap) 197 { 198 ieee80211_crypto_delglobalkeys(vap); 199 } 200 201 /* 202 * Register a crypto cipher module. 203 */ 204 void 205 ieee80211_crypto_register(const struct ieee80211_cipher *cip) 206 { 207 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) { 208 printf("%s: cipher %s has an invalid cipher index %u\n", 209 __func__, cip->ic_name, cip->ic_cipher); 210 return; 211 } 212 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) { 213 printf("%s: cipher %s registered with a different template\n", 214 __func__, cip->ic_name); 215 return; 216 } 217 ciphers[cip->ic_cipher] = cip; 218 } 219 220 /* 221 * Unregister a crypto cipher module. 222 */ 223 void 224 ieee80211_crypto_unregister(const struct ieee80211_cipher *cip) 225 { 226 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) { 227 printf("%s: cipher %s has an invalid cipher index %u\n", 228 __func__, cip->ic_name, cip->ic_cipher); 229 return; 230 } 231 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) { 232 printf("%s: cipher %s registered with a different template\n", 233 __func__, cip->ic_name); 234 return; 235 } 236 /* NB: don't complain about not being registered */ 237 /* XXX disallow if references */ 238 ciphers[cip->ic_cipher] = NULL; 239 } 240 241 int 242 ieee80211_crypto_available(u_int cipher) 243 { 244 return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL; 245 } 246 247 /* XXX well-known names! */ 248 static const char *cipher_modnames[IEEE80211_CIPHER_MAX] = { 249 [IEEE80211_CIPHER_WEP] = "wlan_wep", 250 [IEEE80211_CIPHER_TKIP] = "wlan_tkip", 251 [IEEE80211_CIPHER_AES_OCB] = "wlan_aes_ocb", 252 [IEEE80211_CIPHER_AES_CCM] = "wlan_ccmp", 253 [IEEE80211_CIPHER_TKIPMIC] = "#4", /* NB: reserved */ 254 [IEEE80211_CIPHER_CKIP] = "wlan_ckip", 255 [IEEE80211_CIPHER_NONE] = "wlan_none", 256 }; 257 258 /* NB: there must be no overlap between user-supplied and device-owned flags */ 259 CTASSERT((IEEE80211_KEY_COMMON & IEEE80211_KEY_DEVICE) == 0); 260 261 /* 262 * Establish a relationship between the specified key and cipher 263 * and, if necessary, allocate a hardware index from the driver. 264 * Note that when a fixed key index is required it must be specified. 265 * 266 * This must be the first call applied to a key; all the other key 267 * routines assume wk_cipher is setup. 268 * 269 * Locking must be handled by the caller using: 270 * ieee80211_key_update_begin(vap); 271 * ieee80211_key_update_end(vap); 272 */ 273 int 274 ieee80211_crypto_newkey(struct ieee80211vap *vap, 275 int cipher, int flags, struct ieee80211_key *key) 276 { 277 struct ieee80211com *ic = vap->iv_ic; 278 const struct ieee80211_cipher *cip; 279 ieee80211_keyix keyix, rxkeyix; 280 void *keyctx; 281 int oflags; 282 283 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 284 "%s: cipher %u flags 0x%x keyix %u\n", 285 __func__, cipher, flags, key->wk_keyix); 286 287 /* 288 * Validate cipher and set reference to cipher routines. 289 */ 290 if (cipher >= IEEE80211_CIPHER_MAX) { 291 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 292 "%s: invalid cipher %u\n", __func__, cipher); 293 vap->iv_stats.is_crypto_badcipher++; 294 return 0; 295 } 296 cip = ciphers[cipher]; 297 if (cip == NULL) { 298 /* 299 * Auto-load cipher module if we have a well-known name 300 * for it. It might be better to use string names rather 301 * than numbers and craft a module name based on the cipher 302 * name; e.g. wlan_cipher_<cipher-name>. 303 */ 304 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 305 "%s: unregistered cipher %u, load module %s\n", 306 __func__, cipher, cipher_modnames[cipher]); 307 ieee80211_load_module(cipher_modnames[cipher]); 308 /* 309 * If cipher module loaded it should immediately 310 * call ieee80211_crypto_register which will fill 311 * in the entry in the ciphers array. 312 */ 313 cip = ciphers[cipher]; 314 if (cip == NULL) { 315 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 316 "%s: unable to load cipher %u, module %s\n", 317 __func__, cipher, cipher_modnames[cipher]); 318 vap->iv_stats.is_crypto_nocipher++; 319 return 0; 320 } 321 } 322 323 oflags = key->wk_flags; 324 flags &= IEEE80211_KEY_COMMON; 325 /* NB: preserve device attributes */ 326 flags |= (oflags & IEEE80211_KEY_DEVICE); 327 /* 328 * If the hardware does not support the cipher then 329 * fallback to a host-based implementation. 330 */ 331 if ((ic->ic_cryptocaps & (1<<cipher)) == 0) { 332 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 333 "%s: no h/w support for cipher %s, falling back to s/w\n", 334 __func__, cip->ic_name); 335 flags |= IEEE80211_KEY_SWCRYPT; 336 } 337 /* 338 * Hardware TKIP with software MIC is an important 339 * combination; we handle it by flagging each key, 340 * the cipher modules honor it. 341 */ 342 if (cipher == IEEE80211_CIPHER_TKIP && 343 (ic->ic_cryptocaps & IEEE80211_CRYPTO_TKIPMIC) == 0) { 344 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 345 "%s: no h/w support for TKIP MIC, falling back to s/w\n", 346 __func__); 347 flags |= IEEE80211_KEY_SWMIC; 348 } 349 350 /* 351 * Bind cipher to key instance. Note we do this 352 * after checking the device capabilities so the 353 * cipher module can optimize space usage based on 354 * whether or not it needs to do the cipher work. 355 */ 356 if (key->wk_cipher != cip || key->wk_flags != flags) { 357 /* 358 * Fillin the flags so cipher modules can see s/w 359 * crypto requirements and potentially allocate 360 * different state and/or attach different method 361 * pointers. 362 */ 363 key->wk_flags = flags; 364 keyctx = cip->ic_attach(vap, key); 365 if (keyctx == NULL) { 366 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 367 "%s: unable to attach cipher %s\n", 368 __func__, cip->ic_name); 369 key->wk_flags = oflags; /* restore old flags */ 370 vap->iv_stats.is_crypto_attachfail++; 371 return 0; 372 } 373 cipher_detach(key); 374 key->wk_cipher = cip; /* XXX refcnt? */ 375 key->wk_private = keyctx; 376 } 377 378 /* 379 * Ask the driver for a key index if we don't have one. 380 * Note that entries in the global key table always have 381 * an index; this means it's safe to call this routine 382 * for these entries just to setup the reference to the 383 * cipher template. Note also that when using software 384 * crypto we also call the driver to give us a key index. 385 */ 386 if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) { 387 if (!dev_key_alloc(vap, key, &keyix, &rxkeyix)) { 388 /* 389 * Unable to setup driver state. 390 */ 391 vap->iv_stats.is_crypto_keyfail++; 392 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 393 "%s: unable to setup cipher %s\n", 394 __func__, cip->ic_name); 395 return 0; 396 } 397 if (key->wk_flags != flags) { 398 /* 399 * Driver overrode flags we setup; typically because 400 * resources were unavailable to handle _this_ key. 401 * Re-attach the cipher context to allow cipher 402 * modules to handle differing requirements. 403 */ 404 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 405 "%s: driver override for cipher %s, flags " 406 "0x%x -> 0x%x\n", __func__, cip->ic_name, 407 oflags, key->wk_flags); 408 keyctx = cip->ic_attach(vap, key); 409 if (keyctx == NULL) { 410 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 411 "%s: unable to attach cipher %s with " 412 "flags 0x%x\n", __func__, cip->ic_name, 413 key->wk_flags); 414 key->wk_flags = oflags; /* restore old flags */ 415 vap->iv_stats.is_crypto_attachfail++; 416 return 0; 417 } 418 cipher_detach(key); 419 key->wk_cipher = cip; /* XXX refcnt? */ 420 key->wk_private = keyctx; 421 } 422 key->wk_keyix = keyix; 423 key->wk_rxkeyix = rxkeyix; 424 key->wk_flags |= IEEE80211_KEY_DEVKEY; 425 } 426 return 1; 427 } 428 429 /* 430 * Remove the key (no locking, for internal use). 431 */ 432 static int 433 _ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key) 434 { 435 KASSERT(key->wk_cipher != NULL, ("No cipher!")); 436 437 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 438 "%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n", 439 __func__, key->wk_cipher->ic_name, 440 key->wk_keyix, key->wk_flags, 441 key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc, 442 key->wk_keylen); 443 444 if (key->wk_flags & IEEE80211_KEY_DEVKEY) { 445 /* 446 * Remove hardware entry. 447 */ 448 /* XXX key cache */ 449 if (!dev_key_delete(vap, key)) { 450 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 451 "%s: driver did not delete key index %u\n", 452 __func__, key->wk_keyix); 453 vap->iv_stats.is_crypto_delkey++; 454 /* XXX recovery? */ 455 } 456 } 457 cipher_detach(key); 458 memset(key, 0, sizeof(*key)); 459 ieee80211_crypto_resetkey(vap, key, IEEE80211_KEYIX_NONE); 460 return 1; 461 } 462 463 /* 464 * Remove the specified key. 465 */ 466 int 467 ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key) 468 { 469 int status; 470 471 ieee80211_key_update_begin(vap); 472 status = _ieee80211_crypto_delkey(vap, key); 473 ieee80211_key_update_end(vap); 474 return status; 475 } 476 477 /* 478 * Clear the global key table. 479 */ 480 void 481 ieee80211_crypto_delglobalkeys(struct ieee80211vap *vap) 482 { 483 int i; 484 485 ieee80211_key_update_begin(vap); 486 for (i = 0; i < IEEE80211_WEP_NKID; i++) 487 (void) _ieee80211_crypto_delkey(vap, &vap->iv_nw_keys[i]); 488 ieee80211_key_update_end(vap); 489 } 490 491 /* 492 * Set the contents of the specified key. 493 * 494 * Locking must be handled by the caller using: 495 * ieee80211_key_update_begin(vap); 496 * ieee80211_key_update_end(vap); 497 */ 498 int 499 ieee80211_crypto_setkey(struct ieee80211vap *vap, struct ieee80211_key *key) 500 { 501 const struct ieee80211_cipher *cip = key->wk_cipher; 502 503 KASSERT(cip != NULL, ("No cipher!")); 504 505 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 506 "%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n", 507 __func__, cip->ic_name, key->wk_keyix, 508 key->wk_flags, ether_sprintf(key->wk_macaddr), 509 key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc, 510 key->wk_keylen); 511 512 if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) { 513 /* XXX nothing allocated, should not happen */ 514 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 515 "%s: no device key setup done; should not happen!\n", 516 __func__); 517 vap->iv_stats.is_crypto_setkey_nokey++; 518 return 0; 519 } 520 /* 521 * Give cipher a chance to validate key contents. 522 * XXX should happen before modifying state. 523 */ 524 if (!cip->ic_setkey(key)) { 525 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 526 "%s: cipher %s rejected key index %u len %u flags 0x%x\n", 527 __func__, cip->ic_name, key->wk_keyix, 528 key->wk_keylen, key->wk_flags); 529 vap->iv_stats.is_crypto_setkey_cipher++; 530 return 0; 531 } 532 return dev_key_set(vap, key); 533 } 534 535 /* 536 * Return index if the key is a WEP key (0..3); -1 otherwise. 537 * 538 * This is different to "get_keyid" which defaults to returning 539 * 0 for unicast keys; it assumes that it won't be used for WEP. 540 */ 541 int 542 ieee80211_crypto_get_key_wepidx(const struct ieee80211vap *vap, 543 const struct ieee80211_key *k) 544 { 545 546 if (k >= &vap->iv_nw_keys[0] && 547 k < &vap->iv_nw_keys[IEEE80211_WEP_NKID]) 548 return (k - vap->iv_nw_keys); 549 return (-1); 550 } 551 552 /* 553 * Note: only supports a single unicast key (0). 554 */ 555 uint8_t 556 ieee80211_crypto_get_keyid(struct ieee80211vap *vap, struct ieee80211_key *k) 557 { 558 if (k >= &vap->iv_nw_keys[0] && 559 k < &vap->iv_nw_keys[IEEE80211_WEP_NKID]) 560 return (k - vap->iv_nw_keys); 561 else 562 return (0); 563 } 564 565 struct ieee80211_key * 566 ieee80211_crypto_get_txkey(struct ieee80211_node *ni, struct mbuf *m) 567 { 568 struct ieee80211vap *vap = ni->ni_vap; 569 struct ieee80211_frame *wh; 570 571 /* 572 * Multicast traffic always uses the multicast key. 573 * 574 * Historically we would fall back to the default 575 * transmit key if there was no unicast key. This 576 * behaviour was documented up to IEEE Std 802.11-2016, 577 * 12.9.2.2 Per-MSDU/Per-A-MSDU Tx pseudocode, in the 578 * 'else' case but is no longer in later versions of 579 * the standard. Additionally falling back to the 580 * group key for unicast was a security risk. 581 */ 582 wh = mtod(m, struct ieee80211_frame *); 583 if (IEEE80211_IS_MULTICAST(wh->i_addr1)) { 584 if (vap->iv_def_txkey == IEEE80211_KEYIX_NONE) { 585 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, 586 wh->i_addr1, 587 "no default transmit key (%s) deftxkey %u", 588 __func__, vap->iv_def_txkey); 589 vap->iv_stats.is_tx_nodefkey++; 590 return NULL; 591 } 592 return &vap->iv_nw_keys[vap->iv_def_txkey]; 593 } 594 595 if (IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey)) 596 return NULL; 597 return &ni->ni_ucastkey; 598 } 599 600 /* 601 * Add privacy headers appropriate for the specified key. 602 */ 603 struct ieee80211_key * 604 ieee80211_crypto_encap(struct ieee80211_node *ni, struct mbuf *m) 605 { 606 struct ieee80211_key *k; 607 const struct ieee80211_cipher *cip; 608 609 if ((k = ieee80211_crypto_get_txkey(ni, m)) != NULL) { 610 cip = k->wk_cipher; 611 return (cip->ic_encap(k, m) ? k : NULL); 612 } 613 614 return NULL; 615 } 616 617 /* 618 * Validate and strip privacy headers (and trailer) for a 619 * received frame that has the WEP/Privacy bit set. 620 */ 621 int 622 ieee80211_crypto_decap(struct ieee80211_node *ni, struct mbuf *m, int hdrlen, 623 struct ieee80211_key **key) 624 { 625 #define IEEE80211_WEP_HDRLEN (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN) 626 #define IEEE80211_WEP_MINLEN \ 627 (sizeof(struct ieee80211_frame) + \ 628 IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN) 629 struct ieee80211vap *vap = ni->ni_vap; 630 struct ieee80211_key *k; 631 struct ieee80211_frame *wh; 632 const struct ieee80211_rx_stats *rxs; 633 const struct ieee80211_cipher *cip; 634 uint8_t keyid; 635 636 /* 637 * Check for hardware decryption and IV stripping. 638 * If the IV is stripped then we definitely can't find a key. 639 * Set the key to NULL but return true; upper layers 640 * will need to handle a NULL key for a successful 641 * decrypt. 642 */ 643 rxs = ieee80211_get_rx_params_ptr(m); 644 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) { 645 if (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) { 646 /* 647 * Hardware decrypted, IV stripped. 648 * We can't find a key with a stripped IV. 649 * Return successful. 650 */ 651 *key = NULL; 652 return (1); 653 } 654 } 655 656 /* NB: this minimum size data frame could be bigger */ 657 if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) { 658 IEEE80211_DPRINTF(vap, IEEE80211_MSG_ANY, 659 "%s: WEP data frame too short, len %u\n", 660 __func__, m->m_pkthdr.len); 661 vap->iv_stats.is_rx_tooshort++; /* XXX need unique stat? */ 662 *key = NULL; 663 return (0); 664 } 665 666 /* 667 * Locate the key. If unicast and there is no unicast 668 * key then we fall back to the key id in the header. 669 * This assumes unicast keys are only configured when 670 * the key id in the header is meaningless (typically 0). 671 */ 672 wh = mtod(m, struct ieee80211_frame *); 673 m_copydata(m, hdrlen + IEEE80211_WEP_IVLEN, sizeof(keyid), &keyid); 674 if (IEEE80211_IS_MULTICAST(wh->i_addr1) || 675 IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey)) 676 k = &vap->iv_nw_keys[keyid >> 6]; 677 else 678 k = &ni->ni_ucastkey; 679 680 /* 681 * Insure crypto header is contiguous and long enough for all 682 * decap work. 683 */ 684 cip = k->wk_cipher; 685 if (m->m_len < hdrlen + cip->ic_header) { 686 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 687 "frame is too short (%d < %u) for crypto decap", 688 cip->ic_name, m->m_len, hdrlen + cip->ic_header); 689 vap->iv_stats.is_rx_tooshort++; 690 *key = NULL; 691 return (0); 692 } 693 694 /* 695 * Attempt decryption. 696 * 697 * If we fail then don't return the key - return NULL 698 * and an error. 699 */ 700 if (cip->ic_decap(k, m, hdrlen)) { 701 /* success */ 702 *key = k; 703 return (1); 704 } 705 706 /* Failure */ 707 *key = NULL; 708 return (0); 709 #undef IEEE80211_WEP_MINLEN 710 #undef IEEE80211_WEP_HDRLEN 711 } 712 713 /* 714 * Check and remove any MIC. 715 */ 716 int 717 ieee80211_crypto_demic(struct ieee80211vap *vap, struct ieee80211_key *k, 718 struct mbuf *m, int force) 719 { 720 const struct ieee80211_cipher *cip; 721 const struct ieee80211_rx_stats *rxs; 722 struct ieee80211_frame *wh; 723 724 rxs = ieee80211_get_rx_params_ptr(m); 725 wh = mtod(m, struct ieee80211_frame *); 726 727 /* 728 * Handle demic / mic errors from hardware-decrypted offload devices. 729 */ 730 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) { 731 if (rxs->c_pktflags & IEEE80211_RX_F_FAIL_MIC) { 732 /* 733 * Hardware has said MIC failed. We don't care about 734 * whether it was stripped or not. 735 * 736 * Eventually - teach the demic methods in crypto 737 * modules to handle a NULL key and not to dereference 738 * it. 739 */ 740 ieee80211_notify_michael_failure(vap, wh, -1); 741 return (0); 742 } 743 744 if (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP) { 745 /* 746 * Hardware has decrypted and not indicated a 747 * MIC failure and has stripped the MIC. 748 * We may not have a key, so for now just 749 * return OK. 750 */ 751 return (1); 752 } 753 } 754 755 /* 756 * If we don't have a key at this point then we don't 757 * have to demic anything. 758 */ 759 if (k == NULL) 760 return (1); 761 762 cip = k->wk_cipher; 763 return (cip->ic_miclen > 0 ? cip->ic_demic(k, m, force) : 1); 764 } 765 766 static void 767 load_ucastkey(void *arg, struct ieee80211_node *ni) 768 { 769 struct ieee80211vap *vap = ni->ni_vap; 770 struct ieee80211_key *k; 771 772 if (vap->iv_state != IEEE80211_S_RUN) 773 return; 774 k = &ni->ni_ucastkey; 775 if (k->wk_flags & IEEE80211_KEY_DEVKEY) 776 dev_key_set(vap, k); 777 } 778 779 /* 780 * Re-load all keys known to the 802.11 layer that may 781 * have hardware state backing them. This is used by 782 * drivers on resume to push keys down into the device. 783 */ 784 void 785 ieee80211_crypto_reload_keys(struct ieee80211com *ic) 786 { 787 struct ieee80211vap *vap; 788 int i; 789 790 /* 791 * Keys in the global key table of each vap. 792 */ 793 /* NB: used only during resume so don't lock for now */ 794 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) { 795 if (vap->iv_state != IEEE80211_S_RUN) 796 continue; 797 for (i = 0; i < IEEE80211_WEP_NKID; i++) { 798 const struct ieee80211_key *k = &vap->iv_nw_keys[i]; 799 if (k->wk_flags & IEEE80211_KEY_DEVKEY) 800 dev_key_set(vap, k); 801 } 802 } 803 /* 804 * Unicast keys. 805 */ 806 ieee80211_iterate_nodes(&ic->ic_sta, load_ucastkey, NULL); 807 } 808 809 /* 810 * Set the default key index for WEP, or KEYIX_NONE for no default TX key. 811 * 812 * This should be done as part of a key update block (iv_key_update_begin / 813 * iv_key_update_end.) 814 */ 815 void 816 ieee80211_crypto_set_deftxkey(struct ieee80211vap *vap, ieee80211_keyix kid) 817 { 818 819 /* XXX TODO: assert we're in a key update block */ 820 821 vap->iv_update_deftxkey(vap, kid); 822 } 823