2 * Copyright (c) 2001 Atsushi Onoe
3 * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 * $FreeBSD: head/sys/net80211/ieee80211_crypto.c 195812 2009-07-21 19:36:32Z sam $
31 * IEEE 802.11 generic crypto support.
35 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
40 #include <sys/socket.h>
43 #include <net/if_media.h>
44 #include <net/ethernet.h> /* XXX ETHER_HDR_LEN */
45 #include <net/route.h>
47 #include <netproto/802_11/ieee80211_var.h>
49 MALLOC_DEFINE(M_80211_CRYPTO, "80211crypto", "802.11 crypto state");
51 static int _ieee80211_crypto_delkey(struct ieee80211vap *,
52 struct ieee80211_key *);
55 * Table of registered cipher modules.
57 static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];
60 * Default "null" key management routines.
63 null_key_alloc(struct ieee80211vap *vap, struct ieee80211_key *k,
64 ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
66 if (!(&vap->iv_nw_keys[0] <= k &&
67 k < &vap->iv_nw_keys[IEEE80211_WEP_NKID])) {
69 * Not in the global key table, the driver should handle this
70 * by allocating a slot in the h/w key table/cache. In
71 * lieu of that return key slot 0 for any unicast key
72 * request. We disallow the request if this is a group key.
73 * This default policy does the right thing for legacy hardware
74 * with a 4 key table. It also handles devices that pass
75 * packets through untouched when marked with the WEP bit
78 if (k->wk_flags & IEEE80211_KEY_GROUP)
80 *keyix = 0; /* NB: use key index 0 for ucast key */
82 *keyix = k - vap->iv_nw_keys;
84 *rxkeyix = IEEE80211_KEYIX_NONE; /* XXX maybe *keyix? */
88 null_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k)
93 null_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k,
94 const uint8_t mac[IEEE80211_ADDR_LEN])
98 static void null_key_update(struct ieee80211vap *vap) {}
101 * Write-arounds for common operations.
104 cipher_detach(struct ieee80211_key *key)
106 key->wk_cipher->ic_detach(key);
109 static __inline void *
110 cipher_attach(struct ieee80211vap *vap, struct ieee80211_key *key)
112 return key->wk_cipher->ic_attach(vap, key);
116 * Wrappers for driver key management methods.
119 dev_key_alloc(struct ieee80211vap *vap,
120 struct ieee80211_key *key,
121 ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
123 return vap->iv_key_alloc(vap, key, keyix, rxkeyix);
127 dev_key_delete(struct ieee80211vap *vap,
128 const struct ieee80211_key *key)
130 return vap->iv_key_delete(vap, key);
134 dev_key_set(struct ieee80211vap *vap, const struct ieee80211_key *key)
136 return vap->iv_key_set(vap, key, key->wk_macaddr);
140 * Setup crypto support for a device/shared instance.
143 ieee80211_crypto_attach(struct ieee80211com *ic)
145 /* NB: we assume everything is pre-zero'd */
146 ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
150 * Teardown crypto support.
153 ieee80211_crypto_detach(struct ieee80211com *ic)
158 * Setup crypto support for a vap.
161 ieee80211_crypto_vattach(struct ieee80211vap *vap)
165 /* NB: we assume everything is pre-zero'd */
166 vap->iv_max_keyix = IEEE80211_WEP_NKID;
167 vap->iv_def_txkey = IEEE80211_KEYIX_NONE;
168 for (i = 0; i < IEEE80211_WEP_NKID; i++)
169 ieee80211_crypto_resetkey(vap, &vap->iv_nw_keys[i],
170 IEEE80211_KEYIX_NONE);
172 * Initialize the driver key support routines to noop entries.
173 * This is useful especially for the cipher test modules.
175 vap->iv_key_alloc = null_key_alloc;
176 vap->iv_key_set = null_key_set;
177 vap->iv_key_delete = null_key_delete;
178 vap->iv_key_update_begin = null_key_update;
179 vap->iv_key_update_end = null_key_update;
183 * Teardown crypto support for a vap.
186 ieee80211_crypto_vdetach(struct ieee80211vap *vap)
188 ieee80211_crypto_delglobalkeys(vap);
192 * Register a crypto cipher module.
195 ieee80211_crypto_register(const struct ieee80211_cipher *cip)
197 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
198 kprintf("%s: cipher %s has an invalid cipher index %u\n",
199 __func__, cip->ic_name, cip->ic_cipher);
202 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
203 kprintf("%s: cipher %s registered with a different template\n",
204 __func__, cip->ic_name);
207 ciphers[cip->ic_cipher] = cip;
211 * Unregister a crypto cipher module.
214 ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
216 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
217 kprintf("%s: cipher %s has an invalid cipher index %u\n",
218 __func__, cip->ic_name, cip->ic_cipher);
221 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
222 kprintf("%s: cipher %s registered with a different template\n",
223 __func__, cip->ic_name);
226 /* NB: don't complain about not being registered */
227 /* XXX disallow if references */
228 ciphers[cip->ic_cipher] = NULL;
232 ieee80211_crypto_available(u_int cipher)
234 return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL;
237 /* XXX well-known names! */
238 static const char *cipher_modnames[IEEE80211_CIPHER_MAX] = {
239 [IEEE80211_CIPHER_WEP] = "wlan_wep",
240 [IEEE80211_CIPHER_TKIP] = "wlan_tkip",
241 [IEEE80211_CIPHER_AES_OCB] = "wlan_aes_ocb",
242 [IEEE80211_CIPHER_AES_CCM] = "wlan_ccmp",
243 [IEEE80211_CIPHER_TKIPMIC] = "#4", /* NB: reserved */
244 [IEEE80211_CIPHER_CKIP] = "wlan_ckip",
245 [IEEE80211_CIPHER_NONE] = "wlan_none",
248 /* NB: there must be no overlap between user-supplied and device-owned flags */
249 CTASSERT((IEEE80211_KEY_COMMON & IEEE80211_KEY_DEVICE) == 0);
252 * Establish a relationship between the specified key and cipher
253 * and, if necessary, allocate a hardware index from the driver.
254 * Note that when a fixed key index is required it must be specified.
256 * This must be the first call applied to a key; all the other key
257 * routines assume wk_cipher is setup.
259 * Locking must be handled by the caller using:
260 * ieee80211_key_update_begin(vap);
261 * ieee80211_key_update_end(vap);
264 ieee80211_crypto_newkey(struct ieee80211vap *vap,
265 int cipher, int flags, struct ieee80211_key *key)
267 struct ieee80211com *ic = vap->iv_ic;
268 const struct ieee80211_cipher *cip;
269 ieee80211_keyix keyix, rxkeyix;
273 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
274 "%s: cipher %u flags 0x%x keyix %u\n",
275 __func__, cipher, flags, key->wk_keyix);
278 * Validate cipher and set reference to cipher routines.
280 if (cipher >= IEEE80211_CIPHER_MAX) {
281 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
282 "%s: invalid cipher %u\n", __func__, cipher);
283 vap->iv_stats.is_crypto_badcipher++;
286 cip = ciphers[cipher];
289 * Auto-load cipher module if we have a well-known name
290 * for it. It might be better to use string names rather
291 * than numbers and craft a module name based on the cipher
292 * name; e.g. wlan_cipher_<cipher-name>.
294 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
295 "%s: unregistered cipher %u, load module %s\n",
296 __func__, cipher, cipher_modnames[cipher]);
297 ieee80211_load_module(cipher_modnames[cipher]);
299 * If cipher module loaded it should immediately
300 * call ieee80211_crypto_register which will fill
301 * in the entry in the ciphers array.
303 cip = ciphers[cipher];
305 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
306 "%s: unable to load cipher %u, module %s\n",
307 __func__, cipher, cipher_modnames[cipher]);
308 vap->iv_stats.is_crypto_nocipher++;
313 oflags = key->wk_flags;
314 flags &= IEEE80211_KEY_COMMON;
315 /* NB: preserve device attributes */
316 flags |= (oflags & IEEE80211_KEY_DEVICE);
318 * If the hardware does not support the cipher then
319 * fallback to a host-based implementation.
321 if ((ic->ic_cryptocaps & (1<<cipher)) == 0) {
322 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
323 "%s: no h/w support for cipher %s, falling back to s/w\n",
324 __func__, cip->ic_name);
325 flags |= IEEE80211_KEY_SWCRYPT;
328 * Hardware TKIP with software MIC is an important
329 * combination; we handle it by flagging each key,
330 * the cipher modules honor it.
332 if (cipher == IEEE80211_CIPHER_TKIP &&
333 (ic->ic_cryptocaps & IEEE80211_CRYPTO_TKIPMIC) == 0) {
334 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
335 "%s: no h/w support for TKIP MIC, falling back to s/w\n",
337 flags |= IEEE80211_KEY_SWMIC;
341 * Bind cipher to key instance. Note we do this
342 * after checking the device capabilities so the
343 * cipher module can optimize space usage based on
344 * whether or not it needs to do the cipher work.
346 if (key->wk_cipher != cip || key->wk_flags != flags) {
348 * Fillin the flags so cipher modules can see s/w
349 * crypto requirements and potentially allocate
350 * different state and/or attach different method
353 key->wk_flags = flags;
354 keyctx = cip->ic_attach(vap, key);
355 if (keyctx == NULL) {
356 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
357 "%s: unable to attach cipher %s\n",
358 __func__, cip->ic_name);
359 key->wk_flags = oflags; /* restore old flags */
360 vap->iv_stats.is_crypto_attachfail++;
364 key->wk_cipher = cip; /* XXX refcnt? */
365 key->wk_private = keyctx;
369 * Ask the driver for a key index if we don't have one.
370 * Note that entries in the global key table always have
371 * an index; this means it's safe to call this routine
372 * for these entries just to setup the reference to the
373 * cipher template. Note also that when using software
374 * crypto we also call the driver to give us a key index.
376 if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) {
377 if (!dev_key_alloc(vap, key, &keyix, &rxkeyix)) {
379 * Unable to setup driver state.
381 vap->iv_stats.is_crypto_keyfail++;
382 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
383 "%s: unable to setup cipher %s\n",
384 __func__, cip->ic_name);
387 if (key->wk_flags != flags) {
389 * Driver overrode flags we setup; typically because
390 * resources were unavailable to handle _this_ key.
391 * Re-attach the cipher context to allow cipher
392 * modules to handle differing requirements.
394 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
395 "%s: driver override for cipher %s, flags "
396 "0x%x -> 0x%x\n", __func__, cip->ic_name,
397 oflags, key->wk_flags);
398 keyctx = cip->ic_attach(vap, key);
399 if (keyctx == NULL) {
400 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
401 "%s: unable to attach cipher %s with "
402 "flags 0x%x\n", __func__, cip->ic_name,
404 key->wk_flags = oflags; /* restore old flags */
405 vap->iv_stats.is_crypto_attachfail++;
409 key->wk_cipher = cip; /* XXX refcnt? */
410 key->wk_private = keyctx;
412 key->wk_keyix = keyix;
413 key->wk_rxkeyix = rxkeyix;
414 key->wk_flags |= IEEE80211_KEY_DEVKEY;
420 * Remove the key (no locking, for internal use).
423 _ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key)
425 KASSERT(key->wk_cipher != NULL, ("No cipher!"));
427 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
428 "%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n",
429 __func__, key->wk_cipher->ic_name,
430 key->wk_keyix, key->wk_flags,
431 key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc,
434 if (key->wk_flags & IEEE80211_KEY_DEVKEY) {
436 * Remove hardware entry.
439 if (!dev_key_delete(vap, key)) {
440 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
441 "%s: driver did not delete key index %u\n",
442 __func__, key->wk_keyix);
443 vap->iv_stats.is_crypto_delkey++;
448 memset(key, 0, sizeof(*key));
449 ieee80211_crypto_resetkey(vap, key, IEEE80211_KEYIX_NONE);
454 * Remove the specified key.
457 ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key)
461 ieee80211_key_update_begin(vap);
462 status = _ieee80211_crypto_delkey(vap, key);
463 ieee80211_key_update_end(vap);
468 * Clear the global key table.
471 ieee80211_crypto_delglobalkeys(struct ieee80211vap *vap)
475 ieee80211_key_update_begin(vap);
476 for (i = 0; i < IEEE80211_WEP_NKID; i++)
477 (void) _ieee80211_crypto_delkey(vap, &vap->iv_nw_keys[i]);
478 ieee80211_key_update_end(vap);
482 * Set the contents of the specified key.
484 * Locking must be handled by the caller using:
485 * ieee80211_key_update_begin(vap);
486 * ieee80211_key_update_end(vap);
489 ieee80211_crypto_setkey(struct ieee80211vap *vap, struct ieee80211_key *key)
491 const struct ieee80211_cipher *cip = key->wk_cipher;
493 KASSERT(cip != NULL, ("No cipher!"));
495 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
496 "%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n",
497 __func__, cip->ic_name, key->wk_keyix,
498 key->wk_flags, ether_sprintf(key->wk_macaddr),
499 key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc,
502 if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) {
503 /* XXX nothing allocated, should not happen */
504 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
505 "%s: no device key setup done; should not happen!\n",
507 vap->iv_stats.is_crypto_setkey_nokey++;
511 * Give cipher a chance to validate key contents.
512 * XXX should happen before modifying state.
514 if (!cip->ic_setkey(key)) {
515 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
516 "%s: cipher %s rejected key index %u len %u flags 0x%x\n",
517 __func__, cip->ic_name, key->wk_keyix,
518 key->wk_keylen, key->wk_flags);
519 vap->iv_stats.is_crypto_setkey_cipher++;
522 return dev_key_set(vap, key);
526 * Add privacy headers appropriate for the specified key.
528 struct ieee80211_key *
529 ieee80211_crypto_encap(struct ieee80211_node *ni, struct mbuf *m)
531 struct ieee80211vap *vap = ni->ni_vap;
532 struct ieee80211_key *k;
533 struct ieee80211_frame *wh;
534 const struct ieee80211_cipher *cip;
538 * Multicast traffic always uses the multicast key.
539 * Otherwise if a unicast key is set we use that and
540 * it is always key index 0. When no unicast key is
541 * set we fall back to the default transmit key.
543 wh = mtod(m, struct ieee80211_frame *);
544 if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
545 IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey)) {
546 if (vap->iv_def_txkey == IEEE80211_KEYIX_NONE) {
547 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO,
549 "no default transmit key (%s) deftxkey %u",
550 __func__, vap->iv_def_txkey);
551 vap->iv_stats.is_tx_nodefkey++;
554 keyid = vap->iv_def_txkey;
555 k = &vap->iv_nw_keys[vap->iv_def_txkey];
558 k = &ni->ni_ucastkey;
561 return (cip->ic_encap(k, m, keyid<<6) ? k : NULL);
565 * Validate and strip privacy headers (and trailer) for a
566 * received frame that has the WEP/Privacy bit set.
568 struct ieee80211_key *
569 ieee80211_crypto_decap(struct ieee80211_node *ni, struct mbuf *m, int hdrlen)
571 #define IEEE80211_WEP_HDRLEN (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
572 #define IEEE80211_WEP_MINLEN \
573 (sizeof(struct ieee80211_frame) + \
574 IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN)
575 struct ieee80211vap *vap = ni->ni_vap;
576 struct ieee80211_key *k;
577 struct ieee80211_frame *wh;
578 const struct ieee80211_cipher *cip;
581 /* NB: this minimum size data frame could be bigger */
582 if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) {
583 IEEE80211_DPRINTF(vap, IEEE80211_MSG_ANY,
584 "%s: WEP data frame too short, len %u\n",
585 __func__, m->m_pkthdr.len);
586 vap->iv_stats.is_rx_tooshort++; /* XXX need unique stat? */
591 * Locate the key. If unicast and there is no unicast
592 * key then we fall back to the key id in the header.
593 * This assumes unicast keys are only configured when
594 * the key id in the header is meaningless (typically 0).
596 wh = mtod(m, struct ieee80211_frame *);
597 m_copydata(m, hdrlen + IEEE80211_WEP_IVLEN, sizeof(keyid), &keyid);
598 if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
599 IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey))
600 k = &vap->iv_nw_keys[keyid >> 6];
602 k = &ni->ni_ucastkey;
605 * Insure crypto header is contiguous for all decap work.
608 if (m->m_len < hdrlen + cip->ic_header &&
609 (m = m_pullup(m, hdrlen + cip->ic_header)) == NULL) {
610 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
611 "unable to pullup %s header", cip->ic_name);
612 vap->iv_stats.is_rx_wepfail++; /* XXX */
616 return (cip->ic_decap(k, m, hdrlen) ? k : NULL);
617 #undef IEEE80211_WEP_MINLEN
618 #undef IEEE80211_WEP_HDRLEN
622 load_ucastkey(void *arg, struct ieee80211_node *ni)
624 struct ieee80211vap *vap = ni->ni_vap;
625 struct ieee80211_key *k;
627 if (vap->iv_state != IEEE80211_S_RUN)
629 k = &ni->ni_ucastkey;
630 if (k->wk_flags & IEEE80211_KEY_DEVKEY)
635 * Re-load all keys known to the 802.11 layer that may
636 * have hardware state backing them. This is used by
637 * drivers on resume to push keys down into the device.
640 ieee80211_crypto_reload_keys(struct ieee80211com *ic)
642 struct ieee80211vap *vap;
646 * Keys in the global key table of each vap.
648 /* NB: used only during resume so don't lock for now */
649 TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) {
650 if (vap->iv_state != IEEE80211_S_RUN)
652 for (i = 0; i < IEEE80211_WEP_NKID; i++) {
653 const struct ieee80211_key *k = &vap->iv_nw_keys[i];
654 if (k->wk_flags & IEEE80211_KEY_DEVKEY)
661 ieee80211_iterate_nodes(&ic->ic_sta, load_ucastkey, NULL);