1 /*
2  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 /*
7  * Copyright (c) 2001 Atsushi Onoe
8  * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The name of the author may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission.
21  *
22  * Alternatively, this software may be distributed under the terms of the
23  * GNU General Public License ("GPL") version 2 as published by the Free
24  * Software Foundation.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 #pragma ident	"%Z%%M%	%I%	%E% SMI"
39 
40 /*
41  * IEEE 802.11 generic crypto support
42  */
43 #include <sys/types.h>
44 #include <sys/note.h>
45 #include <sys/crypto/common.h>
46 #include <sys/crypto/api.h>
47 #include <sys/strsun.h>
48 #include "net80211_impl.h"
49 
50 extern const struct ieee80211_cipher wep;
51 extern const struct ieee80211_cipher tkip;
52 extern const struct ieee80211_cipher ccmp;
53 
54 /*
55  * Table of registered cipher modules.
56  */
57 static const char *cipher_modnames[] = {
58 	"wlan_wep",	/* IEEE80211_CIPHER_WEP */
59 	"wlan_tkip",	/* IEEE80211_CIPHER_TKIP */
60 	"wlan_aes_ocb",	/* IEEE80211_CIPHER_AES_OCB */
61 	"wlan_ccmp",	/* IEEE80211_CIPHER_AES_CCM */
62 	"wlan_ckip",	/* IEEE80211_CIPHER_CKIP */
63 };
64 
65 /*
66  * Default "null" key management routines.
67  */
68 /* ARGSUSED */
69 static int
nulldev_key_alloc(ieee80211com_t * ic,const struct ieee80211_key * k,ieee80211_keyix * keyix,ieee80211_keyix * rxkeyix)70 nulldev_key_alloc(ieee80211com_t *ic, const struct ieee80211_key *k,
71 	ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
72 {
73 	*keyix = 0;	/* use key index 0 for ucast key */
74 	*rxkeyix = IEEE80211_KEYIX_NONE;
75 	return (1);
76 }
77 
78 /* ARGSUSED */
79 static int
nulldev_key_delete(ieee80211com_t * ic,const struct ieee80211_key * k)80 nulldev_key_delete(ieee80211com_t *ic, const struct ieee80211_key *k)
81 {
82 	return (1);
83 }
84 
85 /* ARGSUSED */
86 static int
nulldev_key_set(ieee80211com_t * ic,const struct ieee80211_key * k,const uint8_t * mac)87 nulldev_key_set(ieee80211com_t *ic, const struct ieee80211_key *k,
88 	const uint8_t *mac)
89 {
90 	return (1);
91 }
92 
93 /* ARGSUSED */
94 static void
nulldev_key_update(ieee80211com_t * ic)95 nulldev_key_update(ieee80211com_t *ic)
96 {
97 	/* noop */
98 }
99 
100 /*
101  * Reset key state to an unused state.  The crypto
102  * key allocation mechanism insures other state (e.g.
103  * key data) is properly setup before a key is used.
104  */
105 void
ieee80211_crypto_resetkey(ieee80211com_t * ic,struct ieee80211_key * k,ieee80211_keyix ix)106 ieee80211_crypto_resetkey(ieee80211com_t *ic,
107     struct ieee80211_key *k, ieee80211_keyix ix)
108 {
109 	k->wk_cipher = &ieee80211_cipher_none;
110 	k->wk_private = k->wk_cipher->ic_attach(ic, k);
111 	k->wk_keyix = ix;
112 	k->wk_flags = IEEE80211_KEY_XMIT | IEEE80211_KEY_RECV;
113 }
114 
115 /*
116  * Establish a relationship between the specified key and cipher
117  * and, if necessary, allocate a hardware index from the driver.
118  * Note that when a fixed key index is required it must be specified
119  * and we blindly assign it w/o consulting the driver.
120  *
121  * This must be the first call applied to a key; all the other key
122  * routines assume wk_cipher is setup.
123  *
124  * Locking must be handled by the caller using:
125  *	ieee80211_key_update_begin(ic);
126  *	ieee80211_key_update_end(ic);
127  */
128 int
ieee80211_crypto_newkey(ieee80211com_t * ic,int cipher,int flags,struct ieee80211_key * key)129 ieee80211_crypto_newkey(ieee80211com_t *ic, int cipher, int flags,
130     struct ieee80211_key *key)
131 {
132 	const struct ieee80211_cipher *cip;
133 	ieee80211_keyix keyix, rxkeyix;
134 	void *keyctx;
135 	uint16_t oflags;
136 
137 	/*
138 	 * Validate cipher and set reference to cipher routines.
139 	 */
140 	if (cipher >= IEEE80211_CIPHER_MAX) {
141 		ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_newkey: "
142 		    "invalid cipher %u\n", cipher);
143 		return (0);
144 	}
145 	cip = ic->ic_ciphers[cipher];
146 	/* already load all the ciphers, cip can't be NULL */
147 	if (cip == NULL) {
148 		ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_newkey: "
149 		    "unable to load cipher %u, module %s\n",
150 		    cipher, cipher < IEEE80211_N(cipher_modnames) ?
151 		    cipher_modnames[cipher] : "<unknown>");
152 		return (0);
153 	}
154 
155 	oflags = key->wk_flags;
156 	flags &= IEEE80211_KEY_COMMON;
157 	/*
158 	 * If the hardware does not support the cipher then
159 	 * fallback to a host-based implementation.
160 	 */
161 	if ((ic->ic_caps & (1<<cipher)) == 0) {
162 		ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_newkey: "
163 		    "no h/w support for cipher %s, falling back to s/w\n",
164 		    cip->ic_name);
165 		flags |= IEEE80211_KEY_SWCRYPT;
166 	}
167 	/*
168 	 * Hardware TKIP with software MIC is an important
169 	 * combination; we handle it by flagging each key,
170 	 * the cipher modules honor it.
171 	 */
172 	if (cipher == IEEE80211_CIPHER_TKIP &&
173 	    (ic->ic_caps & IEEE80211_C_TKIPMIC) == 0) {
174 		ieee80211_dbg(IEEE80211_MSG_CRYPTO,
175 		    "no h/w support for TKIP MIC, falling back to s/w\n");
176 		flags |= IEEE80211_KEY_SWMIC;
177 	}
178 
179 	/*
180 	 * Bind cipher to key instance.  Note we do this
181 	 * after checking the device capabilities so the
182 	 * cipher module can optimize space usage based on
183 	 * whether or not it needs to do the cipher work.
184 	 */
185 	if (key->wk_cipher != cip || key->wk_flags != flags) {
186 again:
187 		/*
188 		 * Fillin the flags so cipher modules can see s/w
189 		 * crypto requirements and potentially allocate
190 		 * different state and/or attach different method
191 		 * pointers.
192 		 */
193 		key->wk_flags = (uint16_t)flags;
194 		keyctx = cip->ic_attach(ic, key);
195 		if (keyctx == NULL) {
196 			ieee80211_dbg(IEEE80211_MSG_CRYPTO, "crypto_setkey: "
197 			    "unable to attach cipher %s\n", cip->ic_name);
198 			key->wk_flags = oflags;	/* restore old flags */
199 			return (0);
200 		}
201 		CIPHER_DETACH(key);		/* Detach old cipher */
202 		key->wk_cipher = cip;
203 		key->wk_private = keyctx;
204 	}
205 	/*
206 	 * Commit to requested usage so driver can see the flags.
207 	 */
208 	key->wk_flags = (uint16_t)flags;
209 
210 	/*
211 	 * Ask the driver for a key index if we don't have one.
212 	 * Note that entries in the global key table always have
213 	 * an index; this means it's safe to call this routine
214 	 * for these entries just to setup the reference to the
215 	 * cipher template.  Note also that when using software
216 	 * crypto we also call the driver to give us a key index.
217 	 */
218 	if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
219 		if (!DEV_KEY_ALLOC(ic, key, &keyix, &rxkeyix)) {
220 			/*
221 			 * Driver has no room; fallback to doing crypto
222 			 * in the host.  We change the flags and start the
223 			 * procedure over.  If we get back here then there's
224 			 * no hope and we bail.  Note that this can leave
225 			 * the key in a inconsistent state if the caller
226 			 * continues to use it.
227 			 */
228 			if ((key->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) {
229 				ieee80211_dbg(IEEE80211_MSG_CRYPTO,
230 				    "crypto_setkey: "
231 				    "no h/w resources for cipher %s, "
232 				    "falling back to s/w\n", cip->ic_name);
233 				oflags = key->wk_flags;
234 				flags |= IEEE80211_KEY_SWCRYPT;
235 				if (cipher == IEEE80211_CIPHER_TKIP)
236 					flags |= IEEE80211_KEY_SWMIC;
237 				goto again;
238 			}
239 			ieee80211_dbg(IEEE80211_MSG_CRYPTO, "crypto_setkey: "
240 			    "unable to setup cipher %s\n", cip->ic_name);
241 			return (0);
242 		}
243 		key->wk_keyix = keyix;
244 		key->wk_rxkeyix = rxkeyix;
245 	}
246 	return (1);
247 }
248 
249 /*
250  * Remove the key (no locking, for internal use).
251  */
252 static int
ieee80211_crypto_delkey_locked(ieee80211com_t * ic,struct ieee80211_key * key)253 ieee80211_crypto_delkey_locked(ieee80211com_t *ic, struct ieee80211_key *key)
254 {
255 	uint16_t keyix;
256 
257 	ASSERT(key->wk_cipher != NULL);
258 
259 	keyix = key->wk_keyix;
260 	if (keyix != IEEE80211_KEYIX_NONE) {
261 		/*
262 		 * Remove hardware entry.
263 		 */
264 		if (!DEV_KEY_DELETE(ic, key)) {
265 			ieee80211_dbg(IEEE80211_MSG_CRYPTO,
266 			    "ieee80211_crypto_delkey_locked: ",
267 			    "driverdeletes key %u failed\n", keyix);
268 		}
269 	}
270 	CIPHER_DETACH(key);
271 	bzero(key, sizeof (struct ieee80211_key));
272 	/* NB: cannot depend on key index to decide this */
273 	ieee80211_crypto_resetkey(ic, key, IEEE80211_KEYIX_NONE);
274 	return (1);
275 }
276 
277 /*
278  * Remove the specified key.
279  */
280 int
ieee80211_crypto_delkey(ieee80211com_t * ic,struct ieee80211_key * key)281 ieee80211_crypto_delkey(ieee80211com_t *ic, struct ieee80211_key *key)
282 {
283 	int status;
284 
285 	KEY_UPDATE_BEGIN(ic);
286 	status = ieee80211_crypto_delkey_locked(ic, key);
287 	KEY_UPDATE_END(ic);
288 	return (status);
289 }
290 
291 /*
292  * Clear the global key table.
293  */
294 static void
ieee80211_crypto_delglobalkeys(ieee80211com_t * ic)295 ieee80211_crypto_delglobalkeys(ieee80211com_t *ic)
296 {
297 	int i;
298 
299 	KEY_UPDATE_BEGIN(ic);
300 	for (i = 0; i < IEEE80211_WEP_NKID; i++)
301 		(void) ieee80211_crypto_delkey_locked(ic, &ic->ic_nw_keys[i]);
302 	KEY_UPDATE_END(ic);
303 }
304 
305 /*
306  * Set the contents of the specified key.
307  *
308  * Locking must be handled by the caller using:
309  *	ieee80211_key_update_begin(ic);
310  *	ieee80211_key_update_end(ic);
311  */
312 int
ieee80211_crypto_setkey(ieee80211com_t * ic,struct ieee80211_key * key,const uint8_t * macaddr)313 ieee80211_crypto_setkey(ieee80211com_t *ic, struct ieee80211_key *key,
314     const uint8_t *macaddr)
315 {
316 	const struct ieee80211_cipher *cip = key->wk_cipher;
317 
318 	ASSERT(cip != NULL);
319 
320 	ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_setkey: "
321 	    "%s keyix %u flags 0x%x mac %s len %u\n",
322 	    cip->ic_name, key->wk_keyix, key->wk_flags,
323 	    ieee80211_macaddr_sprintf(macaddr), key->wk_keylen);
324 
325 	/*
326 	 * Give cipher a chance to validate key contents.
327 	 * should happen before modifying state.
328 	 */
329 	if (cip->ic_setkey(key) == 0) {
330 		ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_setkey: "
331 		    "cipher %s rejected key index %u len %u flags 0x%x\n",
332 		    cip->ic_name, key->wk_keyix, key->wk_keylen,
333 		    key->wk_flags);
334 		return (0);
335 	}
336 	if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
337 		ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_setkey: "
338 		    "no key index; should not happen!\n");
339 		return (0);
340 	}
341 	return (DEV_KEY_SET(ic, key, macaddr));
342 }
343 
344 /*
345  * Return the transmit key to use in sending a frame.
346  */
347 struct ieee80211_key *
ieee80211_crypto_getkey(ieee80211com_t * ic)348 ieee80211_crypto_getkey(ieee80211com_t *ic)
349 {
350 	if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE ||
351 	    KEY_UNDEFINED(ic->ic_nw_keys[ic->ic_def_txkey]))
352 		return (NULL);
353 	return (&ic->ic_nw_keys[ic->ic_def_txkey]);
354 }
355 
356 uint8_t
ieee80211_crypto_getciphertype(ieee80211com_t * ic)357 ieee80211_crypto_getciphertype(ieee80211com_t *ic)
358 {
359 	struct ieee80211_key *key;
360 	uint32_t cipher;
361 	static const uint8_t ciphermap[] = {
362 		WIFI_SEC_WEP,	/* IEEE80211_CIPHER_WEP */
363 		WIFI_SEC_WPA,	/* IEEE80211_CIPHER_TKIP */
364 		(uint8_t)-1,	/* IEEE80211_CIPHER_AES_OCB */
365 		WIFI_SEC_WPA,	/* IEEE80211_CIPHER_AES_CCM */
366 		(uint8_t)-1,	/* IEEE80211_CIPHER_CKIP */
367 		WIFI_SEC_NONE,	/* IEEE80211_CIPHER_NONE */
368 	};
369 
370 	if ((ic->ic_flags & IEEE80211_F_PRIVACY) == 0)
371 		return (WIFI_SEC_NONE);
372 
373 	key = ieee80211_crypto_getkey(ic);
374 	if (key == NULL)
375 		return (WIFI_SEC_NONE);
376 
377 	cipher = key->wk_cipher->ic_cipher;
378 	ASSERT(cipher < IEEE80211_N(ciphermap));
379 	return (ciphermap[cipher]);
380 }
381 
382 /*
383  * Add privacy headers appropriate for the specified key.
384  */
385 struct ieee80211_key *
ieee80211_crypto_encap(ieee80211com_t * ic,mblk_t * mp)386 ieee80211_crypto_encap(ieee80211com_t *ic, mblk_t *mp)
387 {
388 	struct ieee80211_key *k;
389 	const struct ieee80211_cipher *cip;
390 	uint8_t keyix;
391 
392 	if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE) {
393 		ieee80211_dbg(IEEE80211_MSG_CRYPTO,
394 		    "ieee80211_crypto_encap: %s",
395 		    " No default xmit key for frame\n");
396 		return (NULL);
397 	}
398 	keyix = ic->ic_def_txkey;
399 	k = &ic->ic_nw_keys[ic->ic_def_txkey];
400 	cip = k->wk_cipher;
401 	return (cip->ic_encap(k, mp, keyix<<6) ? k : NULL);
402 }
403 
404 /*
405  * Validate and strip privacy headers (and trailer) for a
406  * received frame that has the WEP/Privacy bit set.
407  */
408 struct ieee80211_key *
ieee80211_crypto_decap(ieee80211com_t * ic,mblk_t * mp,int hdrlen)409 ieee80211_crypto_decap(ieee80211com_t *ic, mblk_t *mp, int hdrlen)
410 {
411 	struct ieee80211_key *k;
412 	const struct ieee80211_cipher *cip;
413 	uint8_t *ivp;
414 	uint8_t keyid;
415 
416 	/* NB: this minimum size data frame could be bigger */
417 	if (MBLKL(mp) < IEEE80211_WEP_MINLEN) {
418 		ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_decap:"
419 		    " WEP data frame too short, len %u\n",
420 		    MBLKL(mp));
421 		return (NULL);
422 	}
423 	/*
424 	 * Locate the key. If unicast and there is no unicast
425 	 * key then we fall back to the key id in the header.
426 	 * This assumes unicast keys are only configured when
427 	 * the key id in the header is meaningless (typically 0).
428 	 */
429 	ivp = mp->b_rptr + hdrlen;
430 	keyid = ivp[IEEE80211_WEP_IVLEN];
431 	k = &ic->ic_nw_keys[keyid >> 6];
432 
433 	/* check to avoid panic when wep is on but key is not set */
434 	if (k->wk_cipher == &ieee80211_cipher_none ||
435 	    k->wk_cipher == NULL)
436 		return (NULL);
437 
438 	cip = k->wk_cipher;
439 	return ((cip->ic_decap)(k, mp, hdrlen) ? k : NULL);
440 }
441 
442 /*
443  * Setup crypto support.
444  */
445 void
ieee80211_crypto_attach(ieee80211com_t * ic)446 ieee80211_crypto_attach(ieee80211com_t *ic)
447 {
448 	struct ieee80211_crypto_state *cs = &ic->ic_crypto;
449 	int i;
450 
451 	(void) crypto_mech2id(SUN_CKM_RC4); /* Load RC4 */
452 	(void) crypto_mech2id(SUN_CKM_AES_CBC); /* Load AES-CBC */
453 	(void) crypto_mech2id(SUN_CKM_AES_CCM); /* Load AES-CCM */
454 
455 	/* NB: we assume everything is pre-zero'd */
456 	cs->cs_def_txkey = IEEE80211_KEYIX_NONE;
457 	for (i = 0; i < IEEE80211_WEP_NKID; i++) {
458 		ieee80211_crypto_resetkey(ic, &cs->cs_nw_keys[i],
459 		    IEEE80211_KEYIX_NONE);
460 	}
461 
462 	/*
463 	 * Initialize the driver key support routines to noop entries.
464 	 * This is useful especially for the cipher test modules.
465 	 */
466 	cs->cs_key_alloc = nulldev_key_alloc;
467 	cs->cs_key_set = nulldev_key_set;
468 	cs->cs_key_delete = nulldev_key_delete;
469 	cs->cs_key_update_begin = nulldev_key_update;
470 	cs->cs_key_update_end = nulldev_key_update;
471 
472 	ieee80211_crypto_register(ic, &wep);
473 	ieee80211_crypto_register(ic, &tkip);
474 	ieee80211_crypto_register(ic, &ccmp);
475 }
476 
477 /*
478  * Teardown crypto support.
479  */
480 void
ieee80211_crypto_detach(ieee80211com_t * ic)481 ieee80211_crypto_detach(ieee80211com_t *ic)
482 {
483 	ieee80211_crypto_delglobalkeys(ic);
484 
485 	ieee80211_crypto_unregister(ic, &wep);
486 	ieee80211_crypto_unregister(ic, &tkip);
487 	ieee80211_crypto_unregister(ic, &ccmp);
488 }
489 
490 /*
491  * Register a crypto cipher module.
492  */
493 void
ieee80211_crypto_register(ieee80211com_t * ic,const struct ieee80211_cipher * cip)494 ieee80211_crypto_register(ieee80211com_t *ic,
495     const struct ieee80211_cipher *cip)
496 {
497 	if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
498 		ieee80211_err("ieee80211_crypto_register: "
499 		    "cipher %s has an invalid cipher index %u\n",
500 		    cip->ic_name, cip->ic_cipher);
501 		return;
502 	}
503 	if (ic->ic_ciphers[cip->ic_cipher] != NULL &&
504 	    ic->ic_ciphers[cip->ic_cipher] != cip) {
505 		ieee80211_err("ieee80211_crypto_register: "
506 		    "cipher %s registered with a different template\n",
507 		    cip->ic_name);
508 		return;
509 	}
510 	ic->ic_ciphers[cip->ic_cipher] = cip;
511 }
512 
513 /*
514  * Unregister a crypto cipher module.
515  */
516 void
ieee80211_crypto_unregister(ieee80211com_t * ic,const struct ieee80211_cipher * cip)517 ieee80211_crypto_unregister(ieee80211com_t *ic,
518     const struct ieee80211_cipher *cip)
519 {
520 	if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
521 		ieee80211_err("ieee80211_crypto_unregister: "
522 		    "cipher %s has an invalid cipher index %u\n",
523 		    cip->ic_name, cip->ic_cipher);
524 		return;
525 	}
526 	if (ic->ic_ciphers[cip->ic_cipher] != NULL &&
527 	    ic->ic_ciphers[cip->ic_cipher] != cip) {
528 		ieee80211_err("ieee80211_crypto_unregister: "
529 		    "cipher %s registered with a different template\n",
530 		    cip->ic_name);
531 		return;
532 	}
533 	/* NB: don't complain about not being registered */
534 	ic->ic_ciphers[cip->ic_cipher] = NULL;
535 }
536