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 66 if (!ieee80211_is_key_global(vap, k)) { 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 * Default set of key management types supported by net80211. 160 * 161 * These are supported by software net80211 and announced/ 162 * driven by hostapd + wpa_supplicant. 163 * 164 * Drivers doing full supplicant offload must not set 165 * anything here. 166 * 167 * Note that IEEE80211_C_WPA1 and IEEE80211_C_WPA2 are the 168 * "old" style way of drivers announcing key management 169 * capabilities. There are many, many more key management 170 * suites in 802.11-2016 (see 9.4.2.25.3 - AKM suites.) 171 * For now they still need to be set - these flags are checked 172 * when assembling a beacon to reserve space for the WPA 173 * vendor IE (WPA 1) and RSN IE (WPA 2). 174 */ 175 ic->ic_sw_keymgmtcaps = 0; 176 } 177 178 /* 179 * Teardown crypto support. 180 */ 181 void 182 ieee80211_crypto_detach(struct ieee80211com *ic) 183 { 184 } 185 186 /* 187 * Set the supported ciphers for software encryption. 188 */ 189 void 190 ieee80211_crypto_set_supported_software_ciphers(struct ieee80211com *ic, 191 uint32_t cipher_set) 192 { 193 ic->ic_sw_cryptocaps = cipher_set; 194 } 195 196 /* 197 * Set the supported ciphers for hardware encryption. 198 */ 199 void 200 ieee80211_crypto_set_supported_hardware_ciphers(struct ieee80211com *ic, 201 uint32_t cipher_set) 202 { 203 ic->ic_cryptocaps = cipher_set; 204 } 205 206 /* 207 * Set the supported software key management by the driver. 208 * 209 * These are the key management suites that are supported via 210 * the driver via hostapd/wpa_supplicant. 211 * 212 * Key management which is completely offloaded (ie, the supplicant 213 * runs in hardware/firmware) must not be set here. 214 */ 215 void 216 ieee80211_crypto_set_supported_driver_keymgmt(struct ieee80211com *ic, 217 uint32_t keymgmt_set) 218 { 219 220 ic->ic_sw_keymgmtcaps = keymgmt_set; 221 } 222 223 /* 224 * Setup crypto support for a vap. 225 */ 226 void 227 ieee80211_crypto_vattach(struct ieee80211vap *vap) 228 { 229 int i; 230 231 /* NB: we assume everything is pre-zero'd */ 232 vap->iv_max_keyix = IEEE80211_WEP_NKID; 233 vap->iv_def_txkey = IEEE80211_KEYIX_NONE; 234 for (i = 0; i < IEEE80211_WEP_NKID; i++) 235 ieee80211_crypto_resetkey(vap, &vap->iv_nw_keys[i], 236 IEEE80211_KEYIX_NONE); 237 /* 238 * Initialize the driver key support routines to noop entries. 239 * This is useful especially for the cipher test modules. 240 */ 241 vap->iv_key_alloc = null_key_alloc; 242 vap->iv_key_set = null_key_set; 243 vap->iv_key_delete = null_key_delete; 244 vap->iv_key_update_begin = null_key_update; 245 vap->iv_key_update_end = null_key_update; 246 } 247 248 /* 249 * Teardown crypto support for a vap. 250 */ 251 void 252 ieee80211_crypto_vdetach(struct ieee80211vap *vap) 253 { 254 ieee80211_crypto_delglobalkeys(vap); 255 } 256 257 /* 258 * Register a crypto cipher module. 259 */ 260 void 261 ieee80211_crypto_register(const struct ieee80211_cipher *cip) 262 { 263 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) { 264 printf("%s: cipher %s has an invalid cipher index %u\n", 265 __func__, cip->ic_name, cip->ic_cipher); 266 return; 267 } 268 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) { 269 printf("%s: cipher %s registered with a different template\n", 270 __func__, cip->ic_name); 271 return; 272 } 273 ciphers[cip->ic_cipher] = cip; 274 } 275 276 /* 277 * Unregister a crypto cipher module. 278 */ 279 void 280 ieee80211_crypto_unregister(const struct ieee80211_cipher *cip) 281 { 282 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) { 283 printf("%s: cipher %s has an invalid cipher index %u\n", 284 __func__, cip->ic_name, cip->ic_cipher); 285 return; 286 } 287 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) { 288 printf("%s: cipher %s registered with a different template\n", 289 __func__, cip->ic_name); 290 return; 291 } 292 /* NB: don't complain about not being registered */ 293 /* XXX disallow if references */ 294 ciphers[cip->ic_cipher] = NULL; 295 } 296 297 int 298 ieee80211_crypto_available(u_int cipher) 299 { 300 return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL; 301 } 302 303 /* XXX well-known names! */ 304 static const char *cipher_modnames[IEEE80211_CIPHER_MAX] = { 305 [IEEE80211_CIPHER_WEP] = "wlan_wep", 306 [IEEE80211_CIPHER_TKIP] = "wlan_tkip", 307 [IEEE80211_CIPHER_AES_OCB] = "wlan_aes_ocb", 308 [IEEE80211_CIPHER_AES_CCM] = "wlan_ccmp", 309 [IEEE80211_CIPHER_TKIPMIC] = "#4", /* NB: reserved */ 310 [IEEE80211_CIPHER_CKIP] = "wlan_ckip", 311 [IEEE80211_CIPHER_NONE] = "wlan_none", 312 [IEEE80211_CIPHER_AES_CCM_256] = "wlan_ccmp", 313 [IEEE80211_CIPHER_BIP_CMAC_128] = "wlan_bip_cmac", 314 [IEEE80211_CIPHER_BIP_CMAC_256] = "wlan_bip_cmac", 315 [IEEE80211_CIPHER_BIP_GMAC_128] = "wlan_bip_gmac", 316 [IEEE80211_CIPHER_BIP_GMAC_256] = "wlan_bip_gmac", 317 [IEEE80211_CIPHER_AES_GCM_128] = "wlan_gcmp", 318 [IEEE80211_CIPHER_AES_GCM_256] = "wlan_gcmp", 319 }; 320 321 /* NB: there must be no overlap between user-supplied and device-owned flags */ 322 CTASSERT((IEEE80211_KEY_COMMON & IEEE80211_KEY_DEVICE) == 0); 323 324 /* 325 * Establish a relationship between the specified key and cipher 326 * and, if necessary, allocate a hardware index from the driver. 327 * Note that when a fixed key index is required it must be specified. 328 * 329 * This must be the first call applied to a key; all the other key 330 * routines assume wk_cipher is setup. 331 * 332 * Locking must be handled by the caller using: 333 * ieee80211_key_update_begin(vap); 334 * ieee80211_key_update_end(vap); 335 */ 336 int 337 ieee80211_crypto_newkey(struct ieee80211vap *vap, 338 int cipher, int flags, struct ieee80211_key *key) 339 { 340 struct ieee80211com *ic = vap->iv_ic; 341 const struct ieee80211_cipher *cip; 342 ieee80211_keyix keyix, rxkeyix; 343 void *keyctx; 344 int oflags; 345 346 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 347 "%s: cipher %u flags 0x%x keyix %u\n", 348 __func__, cipher, flags, key->wk_keyix); 349 350 /* 351 * Validate cipher and set reference to cipher routines. 352 */ 353 if (cipher >= IEEE80211_CIPHER_MAX) { 354 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 355 "%s: invalid cipher %u\n", __func__, cipher); 356 vap->iv_stats.is_crypto_badcipher++; 357 return 0; 358 } 359 cip = ciphers[cipher]; 360 if (cip == NULL) { 361 /* 362 * Auto-load cipher module if we have a well-known name 363 * for it. It might be better to use string names rather 364 * than numbers and craft a module name based on the cipher 365 * name; e.g. wlan_cipher_<cipher-name>. 366 */ 367 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 368 "%s: unregistered cipher %u, load module %s\n", 369 __func__, cipher, cipher_modnames[cipher]); 370 ieee80211_load_module(cipher_modnames[cipher]); 371 /* 372 * If cipher module loaded it should immediately 373 * call ieee80211_crypto_register which will fill 374 * in the entry in the ciphers array. 375 */ 376 cip = ciphers[cipher]; 377 if (cip == NULL) { 378 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 379 "%s: unable to load cipher %u, module %s\n", 380 __func__, cipher, cipher_modnames[cipher]); 381 vap->iv_stats.is_crypto_nocipher++; 382 return 0; 383 } 384 } 385 386 oflags = key->wk_flags; 387 flags &= IEEE80211_KEY_COMMON; 388 /* NB: preserve device attributes */ 389 flags |= (oflags & IEEE80211_KEY_DEVICE); 390 /* 391 * If the hardware does not support the cipher then 392 * fallback to a host-based implementation. 393 */ 394 if ((ic->ic_cryptocaps & (1<<cipher)) == 0) { 395 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 396 "%s: no h/w support for cipher %s, falling back to s/w\n", 397 __func__, cip->ic_name); 398 flags |= IEEE80211_KEY_SWCRYPT; 399 } 400 /* 401 * Hardware TKIP with software MIC is an important 402 * combination; we handle it by flagging each key, 403 * the cipher modules honor it. 404 */ 405 if (cipher == IEEE80211_CIPHER_TKIP && 406 (ic->ic_cryptocaps & IEEE80211_CRYPTO_TKIPMIC) == 0) { 407 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 408 "%s: no h/w support for TKIP MIC, falling back to s/w\n", 409 __func__); 410 flags |= IEEE80211_KEY_SWMIC; 411 } 412 413 /* 414 * Bind cipher to key instance. Note we do this 415 * after checking the device capabilities so the 416 * cipher module can optimize space usage based on 417 * whether or not it needs to do the cipher work. 418 */ 419 if (key->wk_cipher != cip || key->wk_flags != flags) { 420 /* 421 * Fillin the flags so cipher modules can see s/w 422 * crypto requirements and potentially allocate 423 * different state and/or attach different method 424 * pointers. 425 */ 426 key->wk_flags = flags; 427 keyctx = cip->ic_attach(vap, key); 428 if (keyctx == NULL) { 429 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 430 "%s: unable to attach cipher %s\n", 431 __func__, cip->ic_name); 432 key->wk_flags = oflags; /* restore old flags */ 433 vap->iv_stats.is_crypto_attachfail++; 434 return 0; 435 } 436 cipher_detach(key); 437 key->wk_cipher = cip; /* XXX refcnt? */ 438 key->wk_private = keyctx; 439 } 440 441 /* 442 * Ask the driver for a key index if we don't have one. 443 * Note that entries in the global key table always have 444 * an index; this means it's safe to call this routine 445 * for these entries just to setup the reference to the 446 * cipher template. Note also that when using software 447 * crypto we also call the driver to give us a key index. 448 */ 449 if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) { 450 if (!dev_key_alloc(vap, key, &keyix, &rxkeyix)) { 451 /* 452 * Unable to setup driver state. 453 */ 454 vap->iv_stats.is_crypto_keyfail++; 455 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 456 "%s: unable to setup cipher %s\n", 457 __func__, cip->ic_name); 458 return 0; 459 } 460 if (key->wk_flags != flags) { 461 /* 462 * Driver overrode flags we setup; typically because 463 * resources were unavailable to handle _this_ key. 464 * Re-attach the cipher context to allow cipher 465 * modules to handle differing requirements. 466 */ 467 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 468 "%s: driver override for cipher %s, flags " 469 "0x%x -> 0x%x\n", __func__, cip->ic_name, 470 oflags, key->wk_flags); 471 keyctx = cip->ic_attach(vap, key); 472 if (keyctx == NULL) { 473 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 474 "%s: unable to attach cipher %s with " 475 "flags 0x%x\n", __func__, cip->ic_name, 476 key->wk_flags); 477 key->wk_flags = oflags; /* restore old flags */ 478 vap->iv_stats.is_crypto_attachfail++; 479 return 0; 480 } 481 cipher_detach(key); 482 key->wk_cipher = cip; /* XXX refcnt? */ 483 key->wk_private = keyctx; 484 } 485 key->wk_keyix = keyix; 486 key->wk_rxkeyix = rxkeyix; 487 key->wk_flags |= IEEE80211_KEY_DEVKEY; 488 } 489 return 1; 490 } 491 492 /* 493 * Remove the key (no locking, for internal use). 494 */ 495 static int 496 _ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key) 497 { 498 KASSERT(key->wk_cipher != NULL, ("No cipher!")); 499 500 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 501 "%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n", 502 __func__, key->wk_cipher->ic_name, 503 key->wk_keyix, key->wk_flags, 504 key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc, 505 key->wk_keylen); 506 507 if (key->wk_flags & IEEE80211_KEY_DEVKEY) { 508 /* 509 * Remove hardware entry. 510 */ 511 /* XXX key cache */ 512 if (!dev_key_delete(vap, key)) { 513 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 514 "%s: driver did not delete key index %u\n", 515 __func__, key->wk_keyix); 516 vap->iv_stats.is_crypto_delkey++; 517 /* XXX recovery? */ 518 } 519 } 520 cipher_detach(key); 521 memset(key, 0, sizeof(*key)); 522 ieee80211_crypto_resetkey(vap, key, IEEE80211_KEYIX_NONE); 523 return 1; 524 } 525 526 /* 527 * Remove the specified key. 528 */ 529 int 530 ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key) 531 { 532 int status; 533 534 ieee80211_key_update_begin(vap); 535 status = _ieee80211_crypto_delkey(vap, key); 536 ieee80211_key_update_end(vap); 537 return status; 538 } 539 540 /* 541 * Clear the global key table. 542 */ 543 void 544 ieee80211_crypto_delglobalkeys(struct ieee80211vap *vap) 545 { 546 int i; 547 548 ieee80211_key_update_begin(vap); 549 for (i = 0; i < IEEE80211_WEP_NKID; i++) 550 (void) _ieee80211_crypto_delkey(vap, &vap->iv_nw_keys[i]); 551 ieee80211_key_update_end(vap); 552 } 553 554 /* 555 * Set the contents of the specified key. 556 * 557 * Locking must be handled by the caller using: 558 * ieee80211_key_update_begin(vap); 559 * ieee80211_key_update_end(vap); 560 */ 561 int 562 ieee80211_crypto_setkey(struct ieee80211vap *vap, struct ieee80211_key *key) 563 { 564 const struct ieee80211_cipher *cip = key->wk_cipher; 565 566 KASSERT(cip != NULL, ("No cipher!")); 567 568 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 569 "%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n", 570 __func__, cip->ic_name, key->wk_keyix, 571 key->wk_flags, ether_sprintf(key->wk_macaddr), 572 key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc, 573 key->wk_keylen); 574 575 if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) { 576 /* XXX nothing allocated, should not happen */ 577 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 578 "%s: no device key setup done; should not happen!\n", 579 __func__); 580 vap->iv_stats.is_crypto_setkey_nokey++; 581 return 0; 582 } 583 /* 584 * Give cipher a chance to validate key contents. 585 * XXX should happen before modifying state. 586 */ 587 if (!cip->ic_setkey(key)) { 588 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, 589 "%s: cipher %s rejected key index %u len %u flags 0x%x\n", 590 __func__, cip->ic_name, key->wk_keyix, 591 key->wk_keylen, key->wk_flags); 592 vap->iv_stats.is_crypto_setkey_cipher++; 593 return 0; 594 } 595 return dev_key_set(vap, key); 596 } 597 598 /* 599 * Return index if the key is a WEP key (0..3); -1 otherwise. 600 * 601 * This is different to "get_keyid" which defaults to returning 602 * 0 for unicast keys; it assumes that it won't be used for WEP. 603 */ 604 int 605 ieee80211_crypto_get_key_wepidx(const struct ieee80211vap *vap, 606 const struct ieee80211_key *k) 607 { 608 609 if (ieee80211_is_key_global(vap, k)) { 610 return (k - vap->iv_nw_keys); 611 } 612 return (-1); 613 } 614 615 /* 616 * Note: only supports a single unicast key (0). 617 */ 618 uint8_t 619 ieee80211_crypto_get_keyid(struct ieee80211vap *vap, struct ieee80211_key *k) 620 { 621 if (ieee80211_is_key_global(vap, k)) { 622 return (k - vap->iv_nw_keys); 623 } 624 625 return (0); 626 } 627 628 struct ieee80211_key * 629 ieee80211_crypto_get_txkey(struct ieee80211_node *ni, struct mbuf *m) 630 { 631 struct ieee80211vap *vap = ni->ni_vap; 632 struct ieee80211_frame *wh; 633 634 /* 635 * Multicast traffic always uses the multicast key. 636 * 637 * Historically we would fall back to the default 638 * transmit key if there was no unicast key. This 639 * behaviour was documented up to IEEE Std 802.11-2016, 640 * 12.9.2.2 Per-MSDU/Per-A-MSDU Tx pseudocode, in the 641 * 'else' case but is no longer in later versions of 642 * the standard. Additionally falling back to the 643 * group key for unicast was a security risk. 644 */ 645 wh = mtod(m, struct ieee80211_frame *); 646 if (IEEE80211_IS_MULTICAST(wh->i_addr1)) { 647 if (vap->iv_def_txkey == IEEE80211_KEYIX_NONE) { 648 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, 649 wh->i_addr1, 650 "no default transmit key (%s) deftxkey %u", 651 __func__, vap->iv_def_txkey); 652 vap->iv_stats.is_tx_nodefkey++; 653 return NULL; 654 } 655 return &vap->iv_nw_keys[vap->iv_def_txkey]; 656 } 657 658 if (IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey)) 659 return NULL; 660 return &ni->ni_ucastkey; 661 } 662 663 /* 664 * Add privacy headers appropriate for the specified key. 665 */ 666 struct ieee80211_key * 667 ieee80211_crypto_encap(struct ieee80211_node *ni, struct mbuf *m) 668 { 669 struct ieee80211_key *k; 670 const struct ieee80211_cipher *cip; 671 672 if ((k = ieee80211_crypto_get_txkey(ni, m)) != NULL) { 673 cip = k->wk_cipher; 674 return (cip->ic_encap(k, m) ? k : NULL); 675 } 676 677 return NULL; 678 } 679 680 /* 681 * Validate and strip privacy headers (and trailer) for a 682 * received frame that has the WEP/Privacy bit set. 683 */ 684 int 685 ieee80211_crypto_decap(struct ieee80211_node *ni, struct mbuf *m, int hdrlen, 686 struct ieee80211_key **key) 687 { 688 #define IEEE80211_WEP_HDRLEN (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN) 689 #define IEEE80211_WEP_MINLEN \ 690 (sizeof(struct ieee80211_frame) + \ 691 IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN) 692 struct ieee80211vap *vap = ni->ni_vap; 693 struct ieee80211_key *k; 694 struct ieee80211_frame *wh; 695 const struct ieee80211_rx_stats *rxs; 696 const struct ieee80211_cipher *cip; 697 uint8_t keyid; 698 699 /* 700 * Check for hardware decryption and IV stripping. 701 * If the IV is stripped then we definitely can't find a key. 702 * Set the key to NULL but return true; upper layers 703 * will need to handle a NULL key for a successful 704 * decrypt. 705 */ 706 rxs = ieee80211_get_rx_params_ptr(m); 707 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) { 708 if (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) { 709 /* 710 * Hardware decrypted, IV stripped. 711 * We can't find a key with a stripped IV. 712 * Return successful. 713 */ 714 *key = NULL; 715 return (1); 716 } 717 } 718 719 /* NB: this minimum size data frame could be bigger */ 720 if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) { 721 IEEE80211_DPRINTF(vap, IEEE80211_MSG_ANY, 722 "%s: WEP data frame too short, len %u\n", 723 __func__, m->m_pkthdr.len); 724 vap->iv_stats.is_rx_tooshort++; /* XXX need unique stat? */ 725 *key = NULL; 726 return (0); 727 } 728 729 /* 730 * Locate the key. If unicast and there is no unicast 731 * key then we fall back to the key id in the header. 732 * This assumes unicast keys are only configured when 733 * the key id in the header is meaningless (typically 0). 734 */ 735 wh = mtod(m, struct ieee80211_frame *); 736 m_copydata(m, hdrlen + IEEE80211_WEP_IVLEN, sizeof(keyid), &keyid); 737 if (IEEE80211_IS_MULTICAST(wh->i_addr1) || 738 IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey)) 739 k = &vap->iv_nw_keys[keyid >> 6]; 740 else 741 k = &ni->ni_ucastkey; 742 743 /* 744 * Insure crypto header is contiguous and long enough for all 745 * decap work. 746 */ 747 cip = k->wk_cipher; 748 if (m->m_len < hdrlen + cip->ic_header) { 749 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, 750 "frame is too short (%d < %u) for crypto decap", 751 cip->ic_name, m->m_len, hdrlen + cip->ic_header); 752 vap->iv_stats.is_rx_tooshort++; 753 *key = NULL; 754 return (0); 755 } 756 757 /* 758 * Attempt decryption. 759 * 760 * If we fail then don't return the key - return NULL 761 * and an error. 762 */ 763 if (cip->ic_decap(k, m, hdrlen)) { 764 /* success */ 765 *key = k; 766 return (1); 767 } 768 769 /* Failure */ 770 *key = NULL; 771 return (0); 772 #undef IEEE80211_WEP_MINLEN 773 #undef IEEE80211_WEP_HDRLEN 774 } 775 776 /* 777 * Check and remove any MIC. 778 */ 779 int 780 ieee80211_crypto_demic(struct ieee80211vap *vap, struct ieee80211_key *k, 781 struct mbuf *m, int force) 782 { 783 const struct ieee80211_cipher *cip; 784 const struct ieee80211_rx_stats *rxs; 785 struct ieee80211_frame *wh; 786 787 rxs = ieee80211_get_rx_params_ptr(m); 788 wh = mtod(m, struct ieee80211_frame *); 789 790 /* 791 * Handle demic / mic errors from hardware-decrypted offload devices. 792 */ 793 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) { 794 if (rxs->c_pktflags & IEEE80211_RX_F_FAIL_MIC) { 795 /* 796 * Hardware has said MIC failed. We don't care about 797 * whether it was stripped or not. 798 * 799 * Eventually - teach the demic methods in crypto 800 * modules to handle a NULL key and not to dereference 801 * it. 802 */ 803 ieee80211_notify_michael_failure(vap, wh, -1); 804 return (0); 805 } 806 807 if (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP) { 808 /* 809 * Hardware has decrypted and not indicated a 810 * MIC failure and has stripped the MIC. 811 * We may not have a key, so for now just 812 * return OK. 813 */ 814 return (1); 815 } 816 } 817 818 /* 819 * If we don't have a key at this point then we don't 820 * have to demic anything. 821 */ 822 if (k == NULL) 823 return (1); 824 825 cip = k->wk_cipher; 826 return (cip->ic_miclen > 0 ? cip->ic_demic(k, m, force) : 1); 827 } 828 829 static void 830 load_ucastkey(void *arg, struct ieee80211_node *ni) 831 { 832 struct ieee80211vap *vap = ni->ni_vap; 833 struct ieee80211_key *k; 834 835 if (vap->iv_state != IEEE80211_S_RUN) 836 return; 837 k = &ni->ni_ucastkey; 838 if (k->wk_flags & IEEE80211_KEY_DEVKEY) 839 dev_key_set(vap, k); 840 } 841 842 /* 843 * Re-load all keys known to the 802.11 layer that may 844 * have hardware state backing them. This is used by 845 * drivers on resume to push keys down into the device. 846 */ 847 void 848 ieee80211_crypto_reload_keys(struct ieee80211com *ic) 849 { 850 struct ieee80211vap *vap; 851 int i; 852 853 /* 854 * Keys in the global key table of each vap. 855 */ 856 /* NB: used only during resume so don't lock for now */ 857 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) { 858 if (vap->iv_state != IEEE80211_S_RUN) 859 continue; 860 for (i = 0; i < IEEE80211_WEP_NKID; i++) { 861 const struct ieee80211_key *k = &vap->iv_nw_keys[i]; 862 if (k->wk_flags & IEEE80211_KEY_DEVKEY) 863 dev_key_set(vap, k); 864 } 865 } 866 /* 867 * Unicast keys. 868 */ 869 ieee80211_iterate_nodes(&ic->ic_sta, load_ucastkey, NULL); 870 } 871 872 /* 873 * Set the default key index for WEP, or KEYIX_NONE for no default TX key. 874 * 875 * This should be done as part of a key update block (iv_key_update_begin / 876 * iv_key_update_end.) 877 */ 878 void 879 ieee80211_crypto_set_deftxkey(struct ieee80211vap *vap, ieee80211_keyix kid) 880 { 881 882 /* XXX TODO: assert we're in a key update block */ 883 884 vap->iv_update_deftxkey(vap, kid); 885 } 886