xref: /freebsd/sys/net80211/ieee80211_crypto.c (revision e9961ea164968bf2bdab210eab69201b4bf2cb37)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2001 Atsushi Onoe
5  * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 /*
31  * IEEE 802.11 generic crypto support.
32  */
33 #include "opt_wlan.h"
34 
35 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/mbuf.h>
39 
40 #include <sys/socket.h>
41 
42 #include <net/if.h>
43 #include <net/if_media.h>
44 #include <net/ethernet.h>		/* XXX ETHER_HDR_LEN */
45 
46 #include <net80211/ieee80211_var.h>
47 
48 MALLOC_DEFINE(M_80211_CRYPTO, "80211crypto", "802.11 crypto state");
49 
50 static	int _ieee80211_crypto_delkey(struct ieee80211vap *,
51 		struct ieee80211_key *);
52 
53 /*
54  * Table of registered cipher modules.
55  */
56 static	const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];
57 
58 /*
59  * Default "null" key management routines.
60  */
61 static int
62 null_key_alloc(struct ieee80211vap *vap, struct ieee80211_key *k,
63 	ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
64 {
65 	if (!(&vap->iv_nw_keys[0] <= k &&
66 	     k < &vap->iv_nw_keys[IEEE80211_WEP_NKID])) {
67 		/*
68 		 * Not in the global key table, the driver should handle this
69 		 * by allocating a slot in the h/w key table/cache.  In
70 		 * lieu of that return key slot 0 for any unicast key
71 		 * request.  We disallow the request if this is a group key.
72 		 * This default policy does the right thing for legacy hardware
73 		 * with a 4 key table.  It also handles devices that pass
74 		 * packets through untouched when marked with the WEP bit
75 		 * and key index 0.
76 		 */
77 		if (k->wk_flags & IEEE80211_KEY_GROUP)
78 			return 0;
79 		*keyix = 0;	/* NB: use key index 0 for ucast key */
80 	} else {
81 		*keyix = ieee80211_crypto_get_key_wepidx(vap, k);
82 	}
83 	*rxkeyix = IEEE80211_KEYIX_NONE;	/* XXX maybe *keyix? */
84 	return 1;
85 }
86 static int
87 null_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k)
88 {
89 	return 1;
90 }
91 static 	int
92 null_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k)
93 {
94 	return 1;
95 }
96 static void null_key_update(struct ieee80211vap *vap) {}
97 
98 /*
99  * Write-arounds for common operations.
100  */
101 static __inline void
102 cipher_detach(struct ieee80211_key *key)
103 {
104 	key->wk_cipher->ic_detach(key);
105 }
106 
107 static __inline void *
108 cipher_attach(struct ieee80211vap *vap, struct ieee80211_key *key)
109 {
110 	return key->wk_cipher->ic_attach(vap, key);
111 }
112 
113 /*
114  * Wrappers for driver key management methods.
115  */
116 static __inline int
117 dev_key_alloc(struct ieee80211vap *vap,
118 	struct ieee80211_key *key,
119 	ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
120 {
121 	return vap->iv_key_alloc(vap, key, keyix, rxkeyix);
122 }
123 
124 static __inline int
125 dev_key_delete(struct ieee80211vap *vap,
126 	const struct ieee80211_key *key)
127 {
128 	return vap->iv_key_delete(vap, key);
129 }
130 
131 static __inline int
132 dev_key_set(struct ieee80211vap *vap, const struct ieee80211_key *key)
133 {
134 	return vap->iv_key_set(vap, key);
135 }
136 
137 /*
138  * Setup crypto support for a device/shared instance.
139  */
140 void
141 ieee80211_crypto_attach(struct ieee80211com *ic)
142 {
143 	/* NB: we assume everything is pre-zero'd */
144 	ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
145 
146 	/*
147 	 * Default set of net80211 supported ciphers.
148 	 *
149 	 * These are the default set that all drivers are expected to
150 	 * support, either/or in hardware and software.
151 	 *
152 	 * Drivers can add their own support to this and the
153 	 * hardware cipher list (ic_cryptocaps.)
154 	 */
155 	ic->ic_sw_cryptocaps = IEEE80211_CRYPTO_WEP |
156 	    IEEE80211_CRYPTO_TKIP | IEEE80211_CRYPTO_AES_CCM;
157 }
158 
159 /*
160  * Teardown crypto support.
161  */
162 void
163 ieee80211_crypto_detach(struct ieee80211com *ic)
164 {
165 }
166 
167 /*
168  * Set the supported ciphers for software encryption.
169  */
170 void
171 ieee80211_crypto_set_supported_software_ciphers(struct ieee80211com *ic,
172     uint32_t cipher_set)
173 {
174 	ic->ic_sw_cryptocaps = cipher_set;
175 }
176 
177 /*
178  * Set the supported ciphers for hardware encryption.
179  */
180 void
181 ieee80211_crypto_set_supported_hardware_ciphers(struct ieee80211com *ic,
182     uint32_t cipher_set)
183 {
184 	ic->ic_cryptocaps = cipher_set;
185 }
186 
187 
188 /*
189  * Setup crypto support for a vap.
190  */
191 void
192 ieee80211_crypto_vattach(struct ieee80211vap *vap)
193 {
194 	int i;
195 
196 	/* NB: we assume everything is pre-zero'd */
197 	vap->iv_max_keyix = IEEE80211_WEP_NKID;
198 	vap->iv_def_txkey = IEEE80211_KEYIX_NONE;
199 	for (i = 0; i < IEEE80211_WEP_NKID; i++)
200 		ieee80211_crypto_resetkey(vap, &vap->iv_nw_keys[i],
201 			IEEE80211_KEYIX_NONE);
202 	/*
203 	 * Initialize the driver key support routines to noop entries.
204 	 * This is useful especially for the cipher test modules.
205 	 */
206 	vap->iv_key_alloc = null_key_alloc;
207 	vap->iv_key_set = null_key_set;
208 	vap->iv_key_delete = null_key_delete;
209 	vap->iv_key_update_begin = null_key_update;
210 	vap->iv_key_update_end = null_key_update;
211 }
212 
213 /*
214  * Teardown crypto support for a vap.
215  */
216 void
217 ieee80211_crypto_vdetach(struct ieee80211vap *vap)
218 {
219 	ieee80211_crypto_delglobalkeys(vap);
220 }
221 
222 /*
223  * Register a crypto cipher module.
224  */
225 void
226 ieee80211_crypto_register(const struct ieee80211_cipher *cip)
227 {
228 	if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
229 		printf("%s: cipher %s has an invalid cipher index %u\n",
230 			__func__, cip->ic_name, cip->ic_cipher);
231 		return;
232 	}
233 	if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
234 		printf("%s: cipher %s registered with a different template\n",
235 			__func__, cip->ic_name);
236 		return;
237 	}
238 	ciphers[cip->ic_cipher] = cip;
239 }
240 
241 /*
242  * Unregister a crypto cipher module.
243  */
244 void
245 ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
246 {
247 	if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
248 		printf("%s: cipher %s has an invalid cipher index %u\n",
249 			__func__, cip->ic_name, cip->ic_cipher);
250 		return;
251 	}
252 	if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
253 		printf("%s: cipher %s registered with a different template\n",
254 			__func__, cip->ic_name);
255 		return;
256 	}
257 	/* NB: don't complain about not being registered */
258 	/* XXX disallow if references */
259 	ciphers[cip->ic_cipher] = NULL;
260 }
261 
262 int
263 ieee80211_crypto_available(u_int cipher)
264 {
265 	return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL;
266 }
267 
268 /* XXX well-known names! */
269 static const char *cipher_modnames[IEEE80211_CIPHER_MAX] = {
270 	[IEEE80211_CIPHER_WEP]	   = "wlan_wep",
271 	[IEEE80211_CIPHER_TKIP]	   = "wlan_tkip",
272 	[IEEE80211_CIPHER_AES_OCB] = "wlan_aes_ocb",
273 	[IEEE80211_CIPHER_AES_CCM] = "wlan_ccmp",
274 	[IEEE80211_CIPHER_TKIPMIC] = "#4",	/* NB: reserved */
275 	[IEEE80211_CIPHER_CKIP]	   = "wlan_ckip",
276 	[IEEE80211_CIPHER_NONE]	   = "wlan_none",
277 };
278 
279 /* NB: there must be no overlap between user-supplied and device-owned flags */
280 CTASSERT((IEEE80211_KEY_COMMON & IEEE80211_KEY_DEVICE) == 0);
281 
282 /*
283  * Establish a relationship between the specified key and cipher
284  * and, if necessary, allocate a hardware index from the driver.
285  * Note that when a fixed key index is required it must be specified.
286  *
287  * This must be the first call applied to a key; all the other key
288  * routines assume wk_cipher is setup.
289  *
290  * Locking must be handled by the caller using:
291  *	ieee80211_key_update_begin(vap);
292  *	ieee80211_key_update_end(vap);
293  */
294 int
295 ieee80211_crypto_newkey(struct ieee80211vap *vap,
296 	int cipher, int flags, struct ieee80211_key *key)
297 {
298 	struct ieee80211com *ic = vap->iv_ic;
299 	const struct ieee80211_cipher *cip;
300 	ieee80211_keyix keyix, rxkeyix;
301 	void *keyctx;
302 	int oflags;
303 
304 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
305 	    "%s: cipher %u flags 0x%x keyix %u\n",
306 	    __func__, cipher, flags, key->wk_keyix);
307 
308 	/*
309 	 * Validate cipher and set reference to cipher routines.
310 	 */
311 	if (cipher >= IEEE80211_CIPHER_MAX) {
312 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
313 		    "%s: invalid cipher %u\n", __func__, cipher);
314 		vap->iv_stats.is_crypto_badcipher++;
315 		return 0;
316 	}
317 	cip = ciphers[cipher];
318 	if (cip == NULL) {
319 		/*
320 		 * Auto-load cipher module if we have a well-known name
321 		 * for it.  It might be better to use string names rather
322 		 * than numbers and craft a module name based on the cipher
323 		 * name; e.g. wlan_cipher_<cipher-name>.
324 		 */
325 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
326 		    "%s: unregistered cipher %u, load module %s\n",
327 		    __func__, cipher, cipher_modnames[cipher]);
328 		ieee80211_load_module(cipher_modnames[cipher]);
329 		/*
330 		 * If cipher module loaded it should immediately
331 		 * call ieee80211_crypto_register which will fill
332 		 * in the entry in the ciphers array.
333 		 */
334 		cip = ciphers[cipher];
335 		if (cip == NULL) {
336 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
337 			    "%s: unable to load cipher %u, module %s\n",
338 			    __func__, cipher, cipher_modnames[cipher]);
339 			vap->iv_stats.is_crypto_nocipher++;
340 			return 0;
341 		}
342 	}
343 
344 	oflags = key->wk_flags;
345 	flags &= IEEE80211_KEY_COMMON;
346 	/* NB: preserve device attributes */
347 	flags |= (oflags & IEEE80211_KEY_DEVICE);
348 	/*
349 	 * If the hardware does not support the cipher then
350 	 * fallback to a host-based implementation.
351 	 */
352 	if ((ic->ic_cryptocaps & (1<<cipher)) == 0) {
353 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
354 		    "%s: no h/w support for cipher %s, falling back to s/w\n",
355 		    __func__, cip->ic_name);
356 		flags |= IEEE80211_KEY_SWCRYPT;
357 	}
358 	/*
359 	 * Hardware TKIP with software MIC is an important
360 	 * combination; we handle it by flagging each key,
361 	 * the cipher modules honor it.
362 	 */
363 	if (cipher == IEEE80211_CIPHER_TKIP &&
364 	    (ic->ic_cryptocaps & IEEE80211_CRYPTO_TKIPMIC) == 0) {
365 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
366 		    "%s: no h/w support for TKIP MIC, falling back to s/w\n",
367 		    __func__);
368 		flags |= IEEE80211_KEY_SWMIC;
369 	}
370 
371 	/*
372 	 * Bind cipher to key instance.  Note we do this
373 	 * after checking the device capabilities so the
374 	 * cipher module can optimize space usage based on
375 	 * whether or not it needs to do the cipher work.
376 	 */
377 	if (key->wk_cipher != cip || key->wk_flags != flags) {
378 		/*
379 		 * Fillin the flags so cipher modules can see s/w
380 		 * crypto requirements and potentially allocate
381 		 * different state and/or attach different method
382 		 * pointers.
383 		 */
384 		key->wk_flags = flags;
385 		keyctx = cip->ic_attach(vap, key);
386 		if (keyctx == NULL) {
387 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
388 				"%s: unable to attach cipher %s\n",
389 				__func__, cip->ic_name);
390 			key->wk_flags = oflags;	/* restore old flags */
391 			vap->iv_stats.is_crypto_attachfail++;
392 			return 0;
393 		}
394 		cipher_detach(key);
395 		key->wk_cipher = cip;		/* XXX refcnt? */
396 		key->wk_private = keyctx;
397 	}
398 
399 	/*
400 	 * Ask the driver for a key index if we don't have one.
401 	 * Note that entries in the global key table always have
402 	 * an index; this means it's safe to call this routine
403 	 * for these entries just to setup the reference to the
404 	 * cipher template.  Note also that when using software
405 	 * crypto we also call the driver to give us a key index.
406 	 */
407 	if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) {
408 		if (!dev_key_alloc(vap, key, &keyix, &rxkeyix)) {
409 			/*
410 			 * Unable to setup driver state.
411 			 */
412 			vap->iv_stats.is_crypto_keyfail++;
413 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
414 			    "%s: unable to setup cipher %s\n",
415 			    __func__, cip->ic_name);
416 			return 0;
417 		}
418 		if (key->wk_flags != flags) {
419 			/*
420 			 * Driver overrode flags we setup; typically because
421 			 * resources were unavailable to handle _this_ key.
422 			 * Re-attach the cipher context to allow cipher
423 			 * modules to handle differing requirements.
424 			 */
425 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
426 			    "%s: driver override for cipher %s, flags "
427 			    "0x%x -> 0x%x\n", __func__, cip->ic_name,
428 			    oflags, key->wk_flags);
429 			keyctx = cip->ic_attach(vap, key);
430 			if (keyctx == NULL) {
431 				IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
432 				    "%s: unable to attach cipher %s with "
433 				    "flags 0x%x\n", __func__, cip->ic_name,
434 				    key->wk_flags);
435 				key->wk_flags = oflags;	/* restore old flags */
436 				vap->iv_stats.is_crypto_attachfail++;
437 				return 0;
438 			}
439 			cipher_detach(key);
440 			key->wk_cipher = cip;		/* XXX refcnt? */
441 			key->wk_private = keyctx;
442 		}
443 		key->wk_keyix = keyix;
444 		key->wk_rxkeyix = rxkeyix;
445 		key->wk_flags |= IEEE80211_KEY_DEVKEY;
446 	}
447 	return 1;
448 }
449 
450 /*
451  * Remove the key (no locking, for internal use).
452  */
453 static int
454 _ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key)
455 {
456 	KASSERT(key->wk_cipher != NULL, ("No cipher!"));
457 
458 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
459 	    "%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n",
460 	    __func__, key->wk_cipher->ic_name,
461 	    key->wk_keyix, key->wk_flags,
462 	    key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc,
463 	    key->wk_keylen);
464 
465 	if (key->wk_flags & IEEE80211_KEY_DEVKEY) {
466 		/*
467 		 * Remove hardware entry.
468 		 */
469 		/* XXX key cache */
470 		if (!dev_key_delete(vap, key)) {
471 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
472 			    "%s: driver did not delete key index %u\n",
473 			    __func__, key->wk_keyix);
474 			vap->iv_stats.is_crypto_delkey++;
475 			/* XXX recovery? */
476 		}
477 	}
478 	cipher_detach(key);
479 	memset(key, 0, sizeof(*key));
480 	ieee80211_crypto_resetkey(vap, key, IEEE80211_KEYIX_NONE);
481 	return 1;
482 }
483 
484 /*
485  * Remove the specified key.
486  */
487 int
488 ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key)
489 {
490 	int status;
491 
492 	ieee80211_key_update_begin(vap);
493 	status = _ieee80211_crypto_delkey(vap, key);
494 	ieee80211_key_update_end(vap);
495 	return status;
496 }
497 
498 /*
499  * Clear the global key table.
500  */
501 void
502 ieee80211_crypto_delglobalkeys(struct ieee80211vap *vap)
503 {
504 	int i;
505 
506 	ieee80211_key_update_begin(vap);
507 	for (i = 0; i < IEEE80211_WEP_NKID; i++)
508 		(void) _ieee80211_crypto_delkey(vap, &vap->iv_nw_keys[i]);
509 	ieee80211_key_update_end(vap);
510 }
511 
512 /*
513  * Set the contents of the specified key.
514  *
515  * Locking must be handled by the caller using:
516  *	ieee80211_key_update_begin(vap);
517  *	ieee80211_key_update_end(vap);
518  */
519 int
520 ieee80211_crypto_setkey(struct ieee80211vap *vap, struct ieee80211_key *key)
521 {
522 	const struct ieee80211_cipher *cip = key->wk_cipher;
523 
524 	KASSERT(cip != NULL, ("No cipher!"));
525 
526 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
527 	    "%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n",
528 	    __func__, cip->ic_name, key->wk_keyix,
529 	    key->wk_flags, ether_sprintf(key->wk_macaddr),
530 	    key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc,
531 	    key->wk_keylen);
532 
533 	if ((key->wk_flags & IEEE80211_KEY_DEVKEY)  == 0) {
534 		/* XXX nothing allocated, should not happen */
535 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
536 		    "%s: no device key setup done; should not happen!\n",
537 		    __func__);
538 		vap->iv_stats.is_crypto_setkey_nokey++;
539 		return 0;
540 	}
541 	/*
542 	 * Give cipher a chance to validate key contents.
543 	 * XXX should happen before modifying state.
544 	 */
545 	if (!cip->ic_setkey(key)) {
546 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
547 		    "%s: cipher %s rejected key index %u len %u flags 0x%x\n",
548 		    __func__, cip->ic_name, key->wk_keyix,
549 		    key->wk_keylen, key->wk_flags);
550 		vap->iv_stats.is_crypto_setkey_cipher++;
551 		return 0;
552 	}
553 	return dev_key_set(vap, key);
554 }
555 
556 /*
557  * Return index if the key is a WEP key (0..3); -1 otherwise.
558  *
559  * This is different to "get_keyid" which defaults to returning
560  * 0 for unicast keys; it assumes that it won't be used for WEP.
561  */
562 int
563 ieee80211_crypto_get_key_wepidx(const struct ieee80211vap *vap,
564     const struct ieee80211_key *k)
565 {
566 
567 	if (k >= &vap->iv_nw_keys[0] &&
568 	    k <  &vap->iv_nw_keys[IEEE80211_WEP_NKID])
569 		return (k - vap->iv_nw_keys);
570 	return (-1);
571 }
572 
573 /*
574  * Note: only supports a single unicast key (0).
575  */
576 uint8_t
577 ieee80211_crypto_get_keyid(struct ieee80211vap *vap, struct ieee80211_key *k)
578 {
579 	if (k >= &vap->iv_nw_keys[0] &&
580 	    k <  &vap->iv_nw_keys[IEEE80211_WEP_NKID])
581 		return (k - vap->iv_nw_keys);
582 	else
583 		return (0);
584 }
585 
586 struct ieee80211_key *
587 ieee80211_crypto_get_txkey(struct ieee80211_node *ni, struct mbuf *m)
588 {
589 	struct ieee80211vap *vap = ni->ni_vap;
590 	struct ieee80211_frame *wh;
591 
592 	/*
593 	 * Multicast traffic always uses the multicast key.
594 	 *
595 	 * Historically we would fall back to the default
596 	 * transmit key if there was no unicast key.  This
597 	 * behaviour was documented up to IEEE Std 802.11-2016,
598 	 * 12.9.2.2 Per-MSDU/Per-A-MSDU Tx pseudocode, in the
599 	 * 'else' case but is no longer in later versions of
600 	 * the standard.  Additionally falling back to the
601 	 * group key for unicast was a security risk.
602 	 */
603 	wh = mtod(m, struct ieee80211_frame *);
604 	if (IEEE80211_IS_MULTICAST(wh->i_addr1)) {
605 		if (vap->iv_def_txkey == IEEE80211_KEYIX_NONE) {
606 			IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO,
607 			    wh->i_addr1,
608 			    "no default transmit key (%s) deftxkey %u",
609 			    __func__, vap->iv_def_txkey);
610 			vap->iv_stats.is_tx_nodefkey++;
611 			return NULL;
612 		}
613 		return &vap->iv_nw_keys[vap->iv_def_txkey];
614 	}
615 
616 	if (IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey))
617 		return NULL;
618 	return &ni->ni_ucastkey;
619 }
620 
621 /*
622  * Add privacy headers appropriate for the specified key.
623  */
624 struct ieee80211_key *
625 ieee80211_crypto_encap(struct ieee80211_node *ni, struct mbuf *m)
626 {
627 	struct ieee80211_key *k;
628 	const struct ieee80211_cipher *cip;
629 
630 	if ((k = ieee80211_crypto_get_txkey(ni, m)) != NULL) {
631 		cip = k->wk_cipher;
632 		return (cip->ic_encap(k, m) ? k : NULL);
633 	}
634 
635 	return NULL;
636 }
637 
638 /*
639  * Validate and strip privacy headers (and trailer) for a
640  * received frame that has the WEP/Privacy bit set.
641  */
642 int
643 ieee80211_crypto_decap(struct ieee80211_node *ni, struct mbuf *m, int hdrlen,
644     struct ieee80211_key **key)
645 {
646 #define	IEEE80211_WEP_HDRLEN	(IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
647 #define	IEEE80211_WEP_MINLEN \
648 	(sizeof(struct ieee80211_frame) + \
649 	IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN)
650 	struct ieee80211vap *vap = ni->ni_vap;
651 	struct ieee80211_key *k;
652 	struct ieee80211_frame *wh;
653 	const struct ieee80211_rx_stats *rxs;
654 	const struct ieee80211_cipher *cip;
655 	uint8_t keyid;
656 
657 	/*
658 	 * Check for hardware decryption and IV stripping.
659 	 * If the IV is stripped then we definitely can't find a key.
660 	 * Set the key to NULL but return true; upper layers
661 	 * will need to handle a NULL key for a successful
662 	 * decrypt.
663 	 */
664 	rxs = ieee80211_get_rx_params_ptr(m);
665 	if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) {
666 		if (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) {
667 			/*
668 			 * Hardware decrypted, IV stripped.
669 			 * We can't find a key with a stripped IV.
670 			 * Return successful.
671 			 */
672 			*key = NULL;
673 			return (1);
674 		}
675 	}
676 
677 	/* NB: this minimum size data frame could be bigger */
678 	if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) {
679 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_ANY,
680 			"%s: WEP data frame too short, len %u\n",
681 			__func__, m->m_pkthdr.len);
682 		vap->iv_stats.is_rx_tooshort++;	/* XXX need unique stat? */
683 		*key = NULL;
684 		return (0);
685 	}
686 
687 	/*
688 	 * Locate the key. If unicast and there is no unicast
689 	 * key then we fall back to the key id in the header.
690 	 * This assumes unicast keys are only configured when
691 	 * the key id in the header is meaningless (typically 0).
692 	 */
693 	wh = mtod(m, struct ieee80211_frame *);
694 	m_copydata(m, hdrlen + IEEE80211_WEP_IVLEN, sizeof(keyid), &keyid);
695 	if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
696 	    IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey))
697 		k = &vap->iv_nw_keys[keyid >> 6];
698 	else
699 		k = &ni->ni_ucastkey;
700 
701 	/*
702 	 * Insure crypto header is contiguous and long enough for all
703 	 * decap work.
704 	 */
705 	cip = k->wk_cipher;
706 	if (m->m_len < hdrlen + cip->ic_header) {
707 		IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
708 		    "frame is too short (%d < %u) for crypto decap",
709 		    cip->ic_name, m->m_len, hdrlen + cip->ic_header);
710 		vap->iv_stats.is_rx_tooshort++;
711 		*key = NULL;
712 		return (0);
713 	}
714 
715 	/*
716 	 * Attempt decryption.
717 	 *
718 	 * If we fail then don't return the key - return NULL
719 	 * and an error.
720 	 */
721 	if (cip->ic_decap(k, m, hdrlen)) {
722 		/* success */
723 		*key = k;
724 		return (1);
725 	}
726 
727 	/* Failure */
728 	*key = NULL;
729 	return (0);
730 #undef IEEE80211_WEP_MINLEN
731 #undef IEEE80211_WEP_HDRLEN
732 }
733 
734 /*
735  * Check and remove any MIC.
736  */
737 int
738 ieee80211_crypto_demic(struct ieee80211vap *vap, struct ieee80211_key *k,
739     struct mbuf *m, int force)
740 {
741 	const struct ieee80211_cipher *cip;
742 	const struct ieee80211_rx_stats *rxs;
743 	struct ieee80211_frame *wh;
744 
745 	rxs = ieee80211_get_rx_params_ptr(m);
746 	wh = mtod(m, struct ieee80211_frame *);
747 
748 	/*
749 	 * Handle demic / mic errors from hardware-decrypted offload devices.
750 	 */
751 	if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) {
752 		if (rxs->c_pktflags & IEEE80211_RX_F_FAIL_MIC) {
753 			/*
754 			 * Hardware has said MIC failed.  We don't care about
755 			 * whether it was stripped or not.
756 			 *
757 			 * Eventually - teach the demic methods in crypto
758 			 * modules to handle a NULL key and not to dereference
759 			 * it.
760 			 */
761 			ieee80211_notify_michael_failure(vap, wh, -1);
762 			return (0);
763 		}
764 
765 		if (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP) {
766 			/*
767 			 * Hardware has decrypted and not indicated a
768 			 * MIC failure and has stripped the MIC.
769 			 * We may not have a key, so for now just
770 			 * return OK.
771 			 */
772 			return (1);
773 		}
774 	}
775 
776 	/*
777 	 * If we don't have a key at this point then we don't
778 	 * have to demic anything.
779 	 */
780 	if (k == NULL)
781 		return (1);
782 
783 	cip = k->wk_cipher;
784 	return (cip->ic_miclen > 0 ? cip->ic_demic(k, m, force) : 1);
785 }
786 
787 static void
788 load_ucastkey(void *arg, struct ieee80211_node *ni)
789 {
790 	struct ieee80211vap *vap = ni->ni_vap;
791 	struct ieee80211_key *k;
792 
793 	if (vap->iv_state != IEEE80211_S_RUN)
794 		return;
795 	k = &ni->ni_ucastkey;
796 	if (k->wk_flags & IEEE80211_KEY_DEVKEY)
797 		dev_key_set(vap, k);
798 }
799 
800 /*
801  * Re-load all keys known to the 802.11 layer that may
802  * have hardware state backing them.  This is used by
803  * drivers on resume to push keys down into the device.
804  */
805 void
806 ieee80211_crypto_reload_keys(struct ieee80211com *ic)
807 {
808 	struct ieee80211vap *vap;
809 	int i;
810 
811 	/*
812 	 * Keys in the global key table of each vap.
813 	 */
814 	/* NB: used only during resume so don't lock for now */
815 	TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) {
816 		if (vap->iv_state != IEEE80211_S_RUN)
817 			continue;
818 		for (i = 0; i < IEEE80211_WEP_NKID; i++) {
819 			const struct ieee80211_key *k = &vap->iv_nw_keys[i];
820 			if (k->wk_flags & IEEE80211_KEY_DEVKEY)
821 				dev_key_set(vap, k);
822 		}
823 	}
824 	/*
825 	 * Unicast keys.
826 	 */
827 	ieee80211_iterate_nodes(&ic->ic_sta, load_ucastkey, NULL);
828 }
829 
830 /*
831  * Set the default key index for WEP, or KEYIX_NONE for no default TX key.
832  *
833  * This should be done as part of a key update block (iv_key_update_begin /
834  * iv_key_update_end.)
835  */
836 void
837 ieee80211_crypto_set_deftxkey(struct ieee80211vap *vap, ieee80211_keyix kid)
838 {
839 
840 	/* XXX TODO: assert we're in a key update block */
841 
842 	vap->iv_update_deftxkey(vap, kid);
843 }
844