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
null_key_alloc(struct ieee80211vap * vap,struct ieee80211_key * k,ieee80211_keyix * keyix,ieee80211_keyix * rxkeyix)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
null_key_delete(struct ieee80211vap * vap,const struct ieee80211_key * k)87 null_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k)
88 {
89 return 1;
90 }
91 static int
null_key_set(struct ieee80211vap * vap,const struct ieee80211_key * k)92 null_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k)
93 {
94 return 1;
95 }
null_key_update(struct ieee80211vap * vap)96 static void null_key_update(struct ieee80211vap *vap) {}
97
98 /*
99 * Write-arounds for common operations.
100 */
101 static __inline void
cipher_detach(struct ieee80211_key * key)102 cipher_detach(struct ieee80211_key *key)
103 {
104 key->wk_cipher->ic_detach(key);
105 }
106
107 static __inline void *
cipher_attach(struct ieee80211vap * vap,struct ieee80211_key * key)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
dev_key_alloc(struct ieee80211vap * vap,struct ieee80211_key * key,ieee80211_keyix * keyix,ieee80211_keyix * rxkeyix)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
dev_key_delete(struct ieee80211vap * vap,const struct ieee80211_key * key)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
dev_key_set(struct ieee80211vap * vap,const struct ieee80211_key * key)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
ieee80211_crypto_attach(struct ieee80211com * ic)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
ieee80211_crypto_detach(struct ieee80211com * ic)182 ieee80211_crypto_detach(struct ieee80211com *ic)
183 {
184 }
185
186 /*
187 * Set the supported ciphers for software encryption.
188 */
189 void
ieee80211_crypto_set_supported_software_ciphers(struct ieee80211com * ic,uint32_t cipher_set)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
ieee80211_crypto_set_supported_hardware_ciphers(struct ieee80211com * ic,uint32_t cipher_set)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
ieee80211_crypto_set_supported_driver_keymgmt(struct ieee80211com * ic,uint32_t keymgmt_set)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
ieee80211_crypto_vattach(struct ieee80211vap * vap)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
ieee80211_crypto_vdetach(struct ieee80211vap * vap)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
ieee80211_crypto_register(const struct ieee80211_cipher * cip)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
ieee80211_crypto_unregister(const struct ieee80211_cipher * cip)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
ieee80211_crypto_available(u_int cipher)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
ieee80211_crypto_newkey(struct ieee80211vap * vap,int cipher,int flags,struct ieee80211_key * key)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
_ieee80211_crypto_delkey(struct ieee80211vap * vap,struct ieee80211_key * key)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
ieee80211_crypto_delkey(struct ieee80211vap * vap,struct ieee80211_key * key)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
ieee80211_crypto_delglobalkeys(struct ieee80211vap * vap)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
ieee80211_crypto_setkey(struct ieee80211vap * vap,struct ieee80211_key * key)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
ieee80211_crypto_get_key_wepidx(const struct ieee80211vap * vap,const struct ieee80211_key * k)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
ieee80211_crypto_get_keyid(struct ieee80211vap * vap,struct ieee80211_key * k)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 *
ieee80211_crypto_get_txkey(struct ieee80211_node * ni,struct mbuf * m)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 *
ieee80211_crypto_encap(struct ieee80211_node * ni,struct mbuf * m)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
ieee80211_crypto_decap(struct ieee80211_node * ni,struct mbuf * m,int hdrlen,struct ieee80211_key ** key)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
ieee80211_crypto_demic(struct ieee80211vap * vap,struct ieee80211_key * k,struct mbuf * m,int force)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
load_ucastkey(void * arg,struct ieee80211_node * ni)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
ieee80211_crypto_reload_keys(struct ieee80211com * ic)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
ieee80211_crypto_set_deftxkey(struct ieee80211vap * vap,ieee80211_keyix kid)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