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 net80211_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 net80211_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 net80211_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 net80211_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 * Check if the software cipher is available; if not then
402 * fail it early.
403 *
404 * Some devices do not support all ciphers in software
405 * (for example they don't support a "raw" data path.)
406 */
407 if ((flags & IEEE80211_KEY_SWCRYPT) &&
408 (ic->ic_sw_cryptocaps & (1<<cipher)) == 0) {
409 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
410 "%s: no s/w support for cipher %s, rejecting\n",
411 __func__, cip->ic_name);
412 vap->iv_stats.is_crypto_swcipherfail++;
413 return (0);
414 }
415 /*
416 * Hardware TKIP with software MIC is an important
417 * combination; we handle it by flagging each key,
418 * the cipher modules honor it.
419 */
420 if (cipher == IEEE80211_CIPHER_TKIP &&
421 (ic->ic_cryptocaps & IEEE80211_CRYPTO_TKIPMIC) == 0) {
422 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
423 "%s: no h/w support for TKIP MIC, falling back to s/w\n",
424 __func__);
425 flags |= IEEE80211_KEY_SWMIC;
426 }
427
428 /*
429 * Bind cipher to key instance. Note we do this
430 * after checking the device capabilities so the
431 * cipher module can optimize space usage based on
432 * whether or not it needs to do the cipher work.
433 */
434 if (key->wk_cipher != cip || key->wk_flags != flags) {
435 /*
436 * Fillin the flags so cipher modules can see s/w
437 * crypto requirements and potentially allocate
438 * different state and/or attach different method
439 * pointers.
440 */
441 key->wk_flags = flags;
442 keyctx = cip->ic_attach(vap, key);
443 if (keyctx == NULL) {
444 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
445 "%s: unable to attach cipher %s\n",
446 __func__, cip->ic_name);
447 key->wk_flags = oflags; /* restore old flags */
448 vap->iv_stats.is_crypto_attachfail++;
449 return 0;
450 }
451 cipher_detach(key);
452 key->wk_cipher = cip; /* XXX refcnt? */
453 key->wk_private = keyctx;
454 }
455
456 /*
457 * Ask the driver for a key index if we don't have one.
458 * Note that entries in the global key table always have
459 * an index; this means it's safe to call this routine
460 * for these entries just to setup the reference to the
461 * cipher template. Note also that when using software
462 * crypto we also call the driver to give us a key index.
463 */
464 if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) {
465 if (!dev_key_alloc(vap, key, &keyix, &rxkeyix)) {
466 /*
467 * Unable to setup driver state.
468 */
469 vap->iv_stats.is_crypto_keyfail++;
470 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
471 "%s: unable to setup cipher %s\n",
472 __func__, cip->ic_name);
473 return 0;
474 }
475 if (key->wk_flags != flags) {
476 /*
477 * Driver overrode flags we setup; typically because
478 * resources were unavailable to handle _this_ key.
479 * Re-attach the cipher context to allow cipher
480 * modules to handle differing requirements.
481 */
482 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
483 "%s: driver override for cipher %s, flags "
484 "%b -> %b\n", __func__, cip->ic_name,
485 oflags, IEEE80211_KEY_BITS,
486 key->wk_flags, IEEE80211_KEY_BITS);
487 keyctx = cip->ic_attach(vap, key);
488 if (keyctx == NULL) {
489 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
490 "%s: unable to attach cipher %s with "
491 "flags %b\n", __func__, cip->ic_name,
492 key->wk_flags, IEEE80211_KEY_BITS);
493 key->wk_flags = oflags; /* restore old flags */
494 vap->iv_stats.is_crypto_attachfail++;
495 return 0;
496 }
497 cipher_detach(key);
498 key->wk_cipher = cip; /* XXX refcnt? */
499 key->wk_private = keyctx;
500 }
501 key->wk_keyix = keyix;
502 key->wk_rxkeyix = rxkeyix;
503 key->wk_flags |= IEEE80211_KEY_DEVKEY;
504 }
505 return 1;
506 }
507
508 /*
509 * Remove the key (no locking, for internal use).
510 */
511 static int
_ieee80211_crypto_delkey(struct ieee80211vap * vap,struct ieee80211_key * key)512 _ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key)
513 {
514 KASSERT(key->wk_cipher != NULL, ("No cipher!"));
515
516 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
517 "%s: %s keyix %u flags %b rsc %ju tsc %ju len %u\n",
518 __func__, key->wk_cipher->ic_name,
519 key->wk_keyix, key->wk_flags, IEEE80211_KEY_BITS,
520 key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc,
521 key->wk_keylen);
522
523 if (key->wk_flags & IEEE80211_KEY_DEVKEY) {
524 /*
525 * Remove hardware entry.
526 */
527 /* XXX key cache */
528 if (!dev_key_delete(vap, key)) {
529 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
530 "%s: driver did not delete key index %u\n",
531 __func__, key->wk_keyix);
532 vap->iv_stats.is_crypto_delkey++;
533 /* XXX recovery? */
534 }
535 }
536 cipher_detach(key);
537 memset(key, 0, sizeof(*key));
538 ieee80211_crypto_resetkey(vap, key, IEEE80211_KEYIX_NONE);
539 return 1;
540 }
541
542 /*
543 * Remove the specified key.
544 */
545 int
ieee80211_crypto_delkey(struct ieee80211vap * vap,struct ieee80211_key * key)546 ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key)
547 {
548 int status;
549
550 ieee80211_key_update_begin(vap);
551 status = _ieee80211_crypto_delkey(vap, key);
552 ieee80211_key_update_end(vap);
553 return status;
554 }
555
556 /*
557 * Clear the global key table.
558 */
559 void
ieee80211_crypto_delglobalkeys(struct ieee80211vap * vap)560 ieee80211_crypto_delglobalkeys(struct ieee80211vap *vap)
561 {
562 int i;
563
564 ieee80211_key_update_begin(vap);
565 for (i = 0; i < IEEE80211_WEP_NKID; i++)
566 (void) _ieee80211_crypto_delkey(vap, &vap->iv_nw_keys[i]);
567 ieee80211_key_update_end(vap);
568 }
569
570 /*
571 * Set the contents of the specified key.
572 *
573 * Locking must be handled by the caller using:
574 * ieee80211_key_update_begin(vap);
575 * ieee80211_key_update_end(vap);
576 */
577 int
ieee80211_crypto_setkey(struct ieee80211vap * vap,struct ieee80211_key * key)578 ieee80211_crypto_setkey(struct ieee80211vap *vap, struct ieee80211_key *key)
579 {
580 const struct ieee80211_cipher *cip = key->wk_cipher;
581
582 KASSERT(cip != NULL, ("No cipher!"));
583
584 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
585 "%s: %s keyix %u flags %b mac %s rsc %ju tsc %ju len %u\n",
586 __func__, cip->ic_name, key->wk_keyix,
587 key->wk_flags, IEEE80211_KEY_BITS, ether_sprintf(key->wk_macaddr),
588 key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc,
589 key->wk_keylen);
590
591 if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) {
592 /* XXX nothing allocated, should not happen */
593 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
594 "%s: no device key setup done; should not happen!\n",
595 __func__);
596 vap->iv_stats.is_crypto_setkey_nokey++;
597 return 0;
598 }
599 /*
600 * Give cipher a chance to validate key contents.
601 * XXX should happen before modifying state.
602 */
603 if (!cip->ic_setkey(key)) {
604 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
605 "%s: cipher %s rejected key index %u len %u flags %b\n",
606 __func__, cip->ic_name, key->wk_keyix,
607 key->wk_keylen, key->wk_flags, IEEE80211_KEY_BITS);
608 vap->iv_stats.is_crypto_setkey_cipher++;
609 return 0;
610 }
611 return dev_key_set(vap, key);
612 }
613
614 /**
615 * @brief Return index if the key is a WEP key (0..3); -1 otherwise.
616 *
617 * This is different to "get_keyid" which defaults to returning
618 * 0 for unicast keys; it assumes that it won't be used for WEP.
619 *
620 * @param vap the current VAP
621 * @param k ieee80211_key to check
622 * @returns 0..3 if it's a global/WEP key, -1 otherwise.
623 */
624 int
ieee80211_crypto_get_key_wepidx(const struct ieee80211vap * vap,const struct ieee80211_key * k)625 ieee80211_crypto_get_key_wepidx(const struct ieee80211vap *vap,
626 const struct ieee80211_key *k)
627 {
628
629 if (ieee80211_is_key_global(vap, k)) {
630 return (k - vap->iv_nw_keys);
631 }
632 return (-1);
633 }
634
635 /**
636 * @brief Return the index of a unicast, global or IGTK key.
637 *
638 * Return the index of a key. For unicast keys the index is 0..1.
639 * For global/WEP keys it's 0..3. For IGTK keys its 4..5.
640 *
641 * TODO: support >1 unicast key
642 * TODO: support IGTK keys
643 *
644 * @param vap the current VAP
645 * @param k ieee80211_key to check
646 * @returns 0..3 for a WEP/global key, 0..1 for unicast key, 4..5 for IGTK key
647 */
648 uint8_t
ieee80211_crypto_get_keyid(struct ieee80211vap * vap,struct ieee80211_key * k)649 ieee80211_crypto_get_keyid(struct ieee80211vap *vap, struct ieee80211_key *k)
650 {
651 if (ieee80211_is_key_global(vap, k)) {
652 return (k - vap->iv_nw_keys);
653 }
654
655 return (0);
656 }
657
658 /**
659 * @param Return the key to use for encrypting an mbuf frame to a node
660 *
661 * This routine chooses a suitable key used to encrypt the given frame with.
662 * It doesn't do the encryption; it only chooses the key. If a key is not
663 * available then the routine will return NULL.
664 *
665 * It's up to the caller to enforce whether a key is absolutely required or not.
666 *
667 * @param ni The ieee80211_node to send the frame to
668 * @param m the mbuf to encrypt
669 * @returns the ieee80211_key to encrypt with, or NULL if there's no suitable key
670 */
671 struct ieee80211_key *
ieee80211_crypto_get_txkey(struct ieee80211_node * ni,struct mbuf * m)672 ieee80211_crypto_get_txkey(struct ieee80211_node *ni, struct mbuf *m)
673 {
674 struct ieee80211vap *vap = ni->ni_vap;
675 struct ieee80211_frame *wh;
676
677 /*
678 * Multicast traffic always uses the multicast key.
679 *
680 * Historically we would fall back to the default
681 * transmit key if there was no unicast key. This
682 * behaviour was documented up to IEEE Std 802.11-2016,
683 * 12.9.2.2 Per-MSDU/Per-A-MSDU Tx pseudocode, in the
684 * 'else' case but is no longer in later versions of
685 * the standard. Additionally falling back to the
686 * group key for unicast was a security risk.
687 */
688 wh = mtod(m, struct ieee80211_frame *);
689 if (IEEE80211_IS_MULTICAST(wh->i_addr1)) {
690 if (vap->iv_def_txkey == IEEE80211_KEYIX_NONE) {
691 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO,
692 wh->i_addr1,
693 "no default transmit key (%s) deftxkey %u",
694 __func__, vap->iv_def_txkey);
695 vap->iv_stats.is_tx_nodefkey++;
696 return NULL;
697 }
698 return &vap->iv_nw_keys[vap->iv_def_txkey];
699 }
700
701 if (IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey))
702 return NULL;
703 return &ni->ni_ucastkey;
704 }
705
706 /**
707 * @brief Privacy encapsulate and encrypt the given mbuf.
708 *
709 * This routine handles the mechanics of encryption - expanding the
710 * mbuf to add privacy headers, IV, ICV, MIC, MMIC, and then encrypts
711 * the given mbuf if required.
712 *
713 * This should be called by the driver in its TX path as part of
714 * encapsulation before passing frames to the hardware/firmware
715 * queues.
716 *
717 * Drivers/hardware which does its own entirely offload path
718 * should still call this for completeness - it indicates to the
719 * driver that the frame itself should be encrypted.
720 *
721 * The driver should have set capability bits in the attach /
722 * key allocation path to disable various encapsulation/encryption
723 * features.
724 *
725 * @param ni ieee80211_node for this frame
726 * @param mbuf mbuf to modify
727 * @returns the key used if the frame is to be encrypted, NULL otherwise
728 */
729 struct ieee80211_key *
ieee80211_crypto_encap(struct ieee80211_node * ni,struct mbuf * m)730 ieee80211_crypto_encap(struct ieee80211_node *ni, struct mbuf *m)
731 {
732 struct ieee80211_key *k;
733 const struct ieee80211_cipher *cip;
734
735 if ((k = ieee80211_crypto_get_txkey(ni, m)) != NULL) {
736 cip = k->wk_cipher;
737 return (cip->ic_encap(k, m) ? k : NULL);
738 }
739
740 return NULL;
741 }
742
743 /**
744 * @brief Decapsulate and validate an encrypted frame.
745 *
746 * This handles an encrypted frame (one with the privacy bit set.)
747 * It also obeys the key / config / receive packet flags for how
748 * the driver says its already been processed.
749 *
750 * Unlike ieee80211_crypto_encap(), this isn't called in the driver.
751 * Instead, drivers passed the potentially decrypted frame - fully,
752 * partial, or not at all - and net80211 will call this as appropriate.
753 *
754 * This handles NICs (like ath(4)) which have a variable size between
755 * the 802.11 header and 802.11 payload due to DMA alignment / encryption
756 * engine concerns.
757 *
758 * If the frame was decrypted and validated successfully then 1 is returned
759 * and the mbuf can be treated as an 802.11 frame. If it is not decrypted
760 * successfully or it was decrypted but failed validation/checks, then
761 * 0 is returned.
762 *
763 * @param ni ieee80211_node for received frame
764 * @param m mbuf frame to receive
765 * @param hdrlen length of the 802.11 header, including trailing null bytes
766 * @param key pointer to ieee80211_key that will be set if appropriate
767 * @returns 0 if the frame wasn't decrypted/validated, 1 if decrypted/validated.
768 */
769 int
ieee80211_crypto_decap(struct ieee80211_node * ni,struct mbuf * m,int hdrlen,struct ieee80211_key ** key)770 ieee80211_crypto_decap(struct ieee80211_node *ni, struct mbuf *m, int hdrlen,
771 struct ieee80211_key **key)
772 {
773 #define IEEE80211_WEP_HDRLEN (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
774 #define IEEE80211_WEP_MINLEN \
775 (sizeof(struct ieee80211_frame) + \
776 IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN)
777 struct ieee80211vap *vap = ni->ni_vap;
778 struct ieee80211_key *k;
779 struct ieee80211_frame *wh;
780 const struct ieee80211_rx_stats *rxs;
781 const struct ieee80211_cipher *cip;
782 uint8_t keyid;
783
784 /*
785 * Check for hardware decryption and IV stripping.
786 * If the IV is stripped then we definitely can't find a key.
787 * Set the key to NULL but return true; upper layers
788 * will need to handle a NULL key for a successful
789 * decrypt.
790 */
791 rxs = ieee80211_get_rx_params_ptr(m);
792 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) {
793 if (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) {
794 /*
795 * Hardware decrypted, IV stripped.
796 * We can't find a key with a stripped IV.
797 * Return successful.
798 */
799 *key = NULL;
800 return (1);
801 }
802 }
803
804 /* NB: this minimum size data frame could be bigger */
805 if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) {
806 IEEE80211_DPRINTF(vap, IEEE80211_MSG_ANY,
807 "%s: WEP data frame too short, len %u\n",
808 __func__, m->m_pkthdr.len);
809 vap->iv_stats.is_rx_tooshort++; /* XXX need unique stat? */
810 *key = NULL;
811 return (0);
812 }
813
814 /*
815 * Locate the key. If unicast and there is no unicast
816 * key then we fall back to the key id in the header.
817 * This assumes unicast keys are only configured when
818 * the key id in the header is meaningless (typically 0).
819 */
820 wh = mtod(m, struct ieee80211_frame *);
821 m_copydata(m, hdrlen + IEEE80211_WEP_IVLEN, sizeof(keyid), &keyid);
822 if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
823 IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey))
824 k = &vap->iv_nw_keys[keyid >> 6];
825 else
826 k = &ni->ni_ucastkey;
827
828 /*
829 * Ensure crypto header is contiguous and long enough for all
830 * decap work.
831 */
832 cip = k->wk_cipher;
833 if (m->m_len < hdrlen + cip->ic_header) {
834 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
835 "frame is too short (%d < %u) for crypto decap",
836 cip->ic_name, m->m_len, hdrlen + cip->ic_header);
837 vap->iv_stats.is_rx_tooshort++;
838 *key = NULL;
839 return (0);
840 }
841
842 /*
843 * Attempt decryption.
844 *
845 * If we fail then don't return the key - return NULL
846 * and an error.
847 */
848 if (cip->ic_decap(k, m, hdrlen)) {
849 /* success */
850 *key = k;
851 return (1);
852 }
853
854 /* Failure */
855 *key = NULL;
856 return (0);
857 #undef IEEE80211_WEP_MINLEN
858 #undef IEEE80211_WEP_HDRLEN
859 }
860
861 /**
862 * @brief Check and remove any post-defragmentation MIC from an MSDU.
863 *
864 * This is called after defragmentation. Crypto types that implement
865 * a MIC/ICV check per MSDU will not implement this function.
866 *
867 * As an example, TKIP decapsulation covers both MIC/ICV checks per
868 * MPDU (the "WEP" ICV) and then a Michael MIC verification on the
869 * defragmented MSDU. Please see 802.11-2020 12.5.2.1.3 (TKIP decapsulation)
870 * for more information.
871 *
872 * @param vap the current VAP
873 * @param k the current key
874 * @param m the mbuf representing the MSDU
875 * @param f set to 1 to force a MSDU MIC check, even if HW decrypted
876 * @returns 0 if error / MIC check failed, 1 if OK
877 */
878 int
ieee80211_crypto_demic(struct ieee80211vap * vap,struct ieee80211_key * k,struct mbuf * m,int force)879 ieee80211_crypto_demic(struct ieee80211vap *vap, struct ieee80211_key *k,
880 struct mbuf *m, int force)
881 {
882 const struct ieee80211_cipher *cip;
883 const struct ieee80211_rx_stats *rxs;
884 struct ieee80211_frame *wh;
885
886 rxs = ieee80211_get_rx_params_ptr(m);
887 wh = mtod(m, struct ieee80211_frame *);
888
889 /*
890 * Handle demic / mic errors from hardware-decrypted offload devices.
891 */
892 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) {
893 if ((rxs->c_pktflags & IEEE80211_RX_F_FAIL_MMIC) != 0) {
894 /*
895 * Hardware has said MMIC failed. We don't care about
896 * whether it was stripped or not.
897 *
898 * Eventually - teach the demic methods in crypto
899 * modules to handle a NULL key and not to dereference
900 * it.
901 */
902 ieee80211_notify_michael_failure(vap, wh,
903 IEEE80211_KEYIX_NONE);
904 return (0);
905 }
906
907 if ((rxs->c_pktflags &
908 (IEEE80211_RX_F_MIC_STRIP|IEEE80211_RX_F_MMIC_STRIP)) != 0) {
909 /*
910 * Hardware has decrypted and not indicated a
911 * MIC failure and has stripped the MIC.
912 * We may not have a key, so for now just
913 * return OK.
914 */
915 return (1);
916 }
917 }
918
919 /*
920 * If we don't have a key at this point then we don't
921 * have to demic anything.
922 */
923 if (k == NULL)
924 return (1);
925
926 cip = k->wk_cipher;
927 return (cip->ic_miclen > 0 ? cip->ic_demic(k, m, force) : 1);
928 }
929
930 static void
load_ucastkey(void * arg,struct ieee80211_node * ni)931 load_ucastkey(void *arg, struct ieee80211_node *ni)
932 {
933 struct ieee80211vap *vap = ni->ni_vap;
934 struct ieee80211_key *k;
935
936 if (vap->iv_state != IEEE80211_S_RUN)
937 return;
938 k = &ni->ni_ucastkey;
939 if (k->wk_flags & IEEE80211_KEY_DEVKEY)
940 dev_key_set(vap, k);
941 }
942
943 /*
944 * Re-load all keys known to the 802.11 layer that may
945 * have hardware state backing them. This is used by
946 * drivers on resume to push keys down into the device.
947 */
948 void
ieee80211_crypto_reload_keys(struct ieee80211com * ic)949 ieee80211_crypto_reload_keys(struct ieee80211com *ic)
950 {
951 struct ieee80211vap *vap;
952 int i;
953
954 /*
955 * Keys in the global key table of each vap.
956 */
957 /* NB: used only during resume so don't lock for now */
958 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) {
959 if (vap->iv_state != IEEE80211_S_RUN)
960 continue;
961 for (i = 0; i < IEEE80211_WEP_NKID; i++) {
962 const struct ieee80211_key *k = &vap->iv_nw_keys[i];
963 if (k->wk_flags & IEEE80211_KEY_DEVKEY)
964 dev_key_set(vap, k);
965 }
966 }
967 /*
968 * Unicast keys.
969 */
970 ieee80211_iterate_nodes(&ic->ic_sta, load_ucastkey, NULL);
971 }
972
973 /*
974 * Set the default key index for WEP, or KEYIX_NONE for no default TX key.
975 *
976 * This should be done as part of a key update block (iv_key_update_begin /
977 * iv_key_update_end.)
978 */
979 void
ieee80211_crypto_set_deftxkey(struct ieee80211vap * vap,ieee80211_keyix kid)980 ieee80211_crypto_set_deftxkey(struct ieee80211vap *vap, ieee80211_keyix kid)
981 {
982
983 /* XXX TODO: assert we're in a key update block */
984
985 vap->iv_update_deftxkey(vap, kid);
986 }
987
988 /**
989 * @brief Calculate the AAD required for this frame for AES-GCM/AES-CCM.
990 *
991 * The contents are described in 802.11-2020 12.5.3.3.3 (Construct AAD)
992 * under AES-CCM and are shared with AES-GCM as covered in 12.5.5.3.3
993 * (Construct AAD) (AES-GCM).
994 *
995 * NOTE: the first two bytes are a 16 bit big-endian length, which are used
996 * by AES-CCM as part of the Adata field (RFC 3610, section 2.2
997 * (Authentication)) to indicate the length of the Adata field itself.
998 * Since this is small and fits in 0xfeff bytes, the length field
999 * uses the two byte big endian option.
1000 *
1001 * AES-GCM doesn't require the length at the beginning and will need to
1002 * skip it.
1003 *
1004 * TODO: net80211 currently doesn't support negotiating SPP (Signaling
1005 * and Payload Protected A-MSDUs) and thus bit 7 of the QoS control field
1006 * is always masked.
1007 *
1008 * TODO: net80211 currently doesn't support DMG (802.11ad) so bit 7
1009 * (A-MSDU present) and bit 8 (A-MSDU type) are always masked.
1010 *
1011 * @param wh 802.11 frame to calculate the AAD over
1012 * @param aad AAD (additional authentication data) buffer
1013 * @param len The AAD buffer length in bytes.
1014 * @returns The number of AAD payload bytes (ignoring the first two
1015 * bytes, which are the AAD payload length in big-endian).
1016 */
1017 uint16_t
ieee80211_crypto_init_aad(const struct ieee80211_frame * wh,uint8_t * aad,int len)1018 ieee80211_crypto_init_aad(const struct ieee80211_frame *wh, uint8_t *aad,
1019 int len)
1020 {
1021 uint16_t aad_len;
1022
1023 memset(aad, 0, len);
1024
1025 /*
1026 * AAD for PV0 MPDUs:
1027 *
1028 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
1029 * A1 | A2 | A3
1030 * SC with bits 4..15 (seq#) masked to zero
1031 * A4 (if present)
1032 * QC (if present)
1033 */
1034 aad[0] = 0; /* AAD length >> 8 */
1035 /* NB: aad[1] set below */
1036 aad[2] = wh->i_fc[0] & 0x8f; /* see above for bitfields */
1037 aad[3] = wh->i_fc[1] & 0xc7; /* see above for bitfields */
1038 /* mask aad[3] b7 if frame is data frame w/ QoS control field */
1039 if (IEEE80211_IS_QOS_ANY(wh))
1040 aad[3] &= 0x7f;
1041
1042 /* NB: we know 3 addresses are contiguous */
1043 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
1044 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
1045 aad[23] = 0; /* all bits masked */
1046 /*
1047 * Construct variable-length portion of AAD based
1048 * on whether this is a 4-address frame/QOS frame.
1049 * We always zero-pad to 32 bytes before running it
1050 * through the cipher.
1051 */
1052 if (IEEE80211_IS_DSTODS(wh)) {
1053 IEEE80211_ADDR_COPY(aad + 24,
1054 ((const struct ieee80211_frame_addr4 *)wh)->i_addr4);
1055 if (IEEE80211_IS_QOS_ANY(wh)) {
1056 const struct ieee80211_qosframe_addr4 *qwh4 =
1057 (const struct ieee80211_qosframe_addr4 *) wh;
1058 /* TODO: SPP A-MSDU / A-MSDU present bit */
1059 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
1060 aad[31] = 0;
1061 aad_len = aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
1062 } else {
1063 *(uint16_t *)&aad[30] = 0;
1064 aad_len = aad[1] = 22 + IEEE80211_ADDR_LEN;
1065 }
1066 } else {
1067 if (IEEE80211_IS_QOS_ANY(wh)) {
1068 const struct ieee80211_qosframe *qwh =
1069 (const struct ieee80211_qosframe*) wh;
1070 /* TODO: SPP A-MSDU / A-MSDU present bit */
1071 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
1072 aad[25] = 0;
1073 aad_len = aad[1] = 22 + 2;
1074 } else {
1075 *(uint16_t *)&aad[24] = 0;
1076 aad_len = aad[1] = 22;
1077 }
1078 *(uint16_t *)&aad[26] = 0;
1079 *(uint32_t *)&aad[28] = 0;
1080 }
1081
1082 return (aad_len);
1083 }
1084