35
36/*
37 * IEEE 802.11 generic crypto support.
38 */
39#include <sys/param.h>
40#include <sys/mbuf.h>
41
42#include <sys/socket.h>
43
44#include <net/if.h>
45#include <net/if_media.h>
46#include <net/ethernet.h> /* XXX ETHER_HDR_LEN */
47
48#include <net80211/ieee80211_var.h>
49
50/*
51 * Table of registered cipher modules.
52 */
53static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];
54
55static int _ieee80211_crypto_delkey(struct ieee80211com *,
56 struct ieee80211_key *);
57
58/*
59 * Default "null" key management routines.
60 */
61static int
62null_key_alloc(struct ieee80211com *ic, const struct ieee80211_key *k)
63{
64 return IEEE80211_KEYIX_NONE;
65}
66static int
67null_key_delete(struct ieee80211com *ic, const struct ieee80211_key *k)
68{
69 return 1;
70}
71static int
72null_key_set(struct ieee80211com *ic, const struct ieee80211_key *k,
73 const u_int8_t mac[IEEE80211_ADDR_LEN])
74{
75 return 1;
76}
77static void null_key_update(struct ieee80211com *ic) {}
78
79/*
80 * Write-arounds for common operations.
81 */
82static __inline void
83cipher_detach(struct ieee80211_key *key)
84{
85 key->wk_cipher->ic_detach(key);
86}
87
88static __inline void *
89cipher_attach(struct ieee80211com *ic, struct ieee80211_key *key)
90{
91 return key->wk_cipher->ic_attach(ic, key);
92}
93
94/*
95 * Wrappers for driver key management methods.
96 */
97static __inline int
98dev_key_alloc(struct ieee80211com *ic,
99 const struct ieee80211_key *key)
100{
101 return ic->ic_crypto.cs_key_alloc(ic, key);
102}
103
104static __inline int
105dev_key_delete(struct ieee80211com *ic,
106 const struct ieee80211_key *key)
107{
108 return ic->ic_crypto.cs_key_delete(ic, key);
109}
110
111static __inline int
112dev_key_set(struct ieee80211com *ic, const struct ieee80211_key *key,
113 const u_int8_t mac[IEEE80211_ADDR_LEN])
114{
115 return ic->ic_crypto.cs_key_set(ic, key, mac);
116}
117
118/*
119 * Setup crypto support.
120 */
121void
122ieee80211_crypto_attach(struct ieee80211com *ic)
123{
124 struct ieee80211_crypto_state *cs = &ic->ic_crypto;
125 int i;
126
127 /* NB: we assume everything is pre-zero'd */
128 cs->cs_def_txkey = IEEE80211_KEYIX_NONE;
129 ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
130 for (i = 0; i < IEEE80211_WEP_NKID; i++)
131 ieee80211_crypto_resetkey(ic, &cs->cs_nw_keys[i], i);
132 /*
133 * Initialize the driver key support routines to noop entries.
134 * This is useful especially for the cipher test modules.
135 */
136 cs->cs_key_alloc = null_key_alloc;
137 cs->cs_key_set = null_key_set;
138 cs->cs_key_delete = null_key_delete;
139 cs->cs_key_update_begin = null_key_update;
140 cs->cs_key_update_end = null_key_update;
141}
142
143/*
144 * Teardown crypto support.
145 */
146void
147ieee80211_crypto_detach(struct ieee80211com *ic)
148{
149 ieee80211_crypto_delglobalkeys(ic);
150}
151
152/*
153 * Register a crypto cipher module.
154 */
155void
156ieee80211_crypto_register(const struct ieee80211_cipher *cip)
157{
158 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
159 printf("%s: cipher %s has an invalid cipher index %u\n",
160 __func__, cip->ic_name, cip->ic_cipher);
161 return;
162 }
163 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
164 printf("%s: cipher %s registered with a different template\n",
165 __func__, cip->ic_name);
166 return;
167 }
168 ciphers[cip->ic_cipher] = cip;
169}
170
171/*
172 * Unregister a crypto cipher module.
173 */
174void
175ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
176{
177 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
178 printf("%s: cipher %s has an invalid cipher index %u\n",
179 __func__, cip->ic_name, cip->ic_cipher);
180 return;
181 }
182 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
183 printf("%s: cipher %s registered with a different template\n",
184 __func__, cip->ic_name);
185 return;
186 }
187 /* NB: don't complain about not being registered */
188 /* XXX disallow if references */
189 ciphers[cip->ic_cipher] = NULL;
190}
191
192int
193ieee80211_crypto_available(u_int cipher)
194{
195 return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL;
196}
197
198/* XXX well-known names! */
199static const char *cipher_modnames[] = {
200 "wlan_wep", /* IEEE80211_CIPHER_WEP */
201 "wlan_tkip", /* IEEE80211_CIPHER_TKIP */
202 "wlan_aes_ocb", /* IEEE80211_CIPHER_AES_OCB */
203 "wlan_ccmp", /* IEEE80211_CIPHER_AES_CCM */
204 "wlan_ckip", /* IEEE80211_CIPHER_CKIP */
205};
206
207/*
208 * Establish a relationship between the specified key and cipher
209 * and, if not a global key, allocate a hardware index from the
210 * driver. Note that we may be called for global keys but they
211 * should have a key index already setup so the only work done
212 * is to setup the cipher reference.
213 *
214 * This must be the first call applied to a key; all the other key
215 * routines assume wk_cipher is setup.
216 *
217 * Locking must be handled by the caller using:
218 * ieee80211_key_update_begin(ic);
219 * ieee80211_key_update_end(ic);
220 */
221int
222ieee80211_crypto_newkey(struct ieee80211com *ic,
223 int cipher, struct ieee80211_key *key)
224{
225#define N(a) (sizeof(a) / sizeof(a[0]))
226 const struct ieee80211_cipher *cip;
227 void *keyctx;
228 int oflags;
229
230 /*
231 * Validate cipher and set reference to cipher routines.
232 */
233 if (cipher >= IEEE80211_CIPHER_MAX) {
234 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
235 "%s: invalid cipher %u\n", __func__, cipher);
236 ic->ic_stats.is_crypto_badcipher++;
237 return 0;
238 }
239 cip = ciphers[cipher];
240 if (cip == NULL) {
241 /*
242 * Auto-load cipher module if we have a well-known name
243 * for it. It might be better to use string names rather
244 * than numbers and craft a module name based on the cipher
245 * name; e.g. wlan_cipher_<cipher-name>.
246 */
247 if (cipher < N(cipher_modnames)) {
248 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
249 "%s: unregistered cipher %u, load module %s\n",
250 __func__, cipher, cipher_modnames[cipher]);
251 ieee80211_load_module(cipher_modnames[cipher]);
252 /*
253 * If cipher module loaded it should immediately
254 * call ieee80211_crypto_register which will fill
255 * in the entry in the ciphers array.
256 */
257 cip = ciphers[cipher];
258 }
259 if (cip == NULL) {
260 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
261 "%s: unable to load cipher %u, module %s\n",
262 __func__, cipher,
263 cipher < N(cipher_modnames) ?
264 cipher_modnames[cipher] : "<unknown>");
265 ic->ic_stats.is_crypto_nocipher++;
266 return 0;
267 }
268 }
269
270 oflags = key->wk_flags;
271 /*
272 * If the hardware does not support the cipher then
273 * fallback to a host-based implementation.
274 */
275 key->wk_flags &= ~(IEEE80211_KEY_SWCRYPT|IEEE80211_KEY_SWMIC);
276 if ((ic->ic_caps & (1<<cipher)) == 0) {
277 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
278 "%s: no h/w support for cipher %s, falling back to s/w\n",
279 __func__, cip->ic_name);
280 key->wk_flags |= IEEE80211_KEY_SWCRYPT;
281 }
282 /*
283 * Hardware TKIP with software MIC is an important
284 * combination; we handle it by flagging each key,
285 * the cipher modules honor it.
286 */
287 if (cipher == IEEE80211_CIPHER_TKIP &&
288 (ic->ic_caps & IEEE80211_C_TKIPMIC) == 0) {
289 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
290 "%s: no h/w support for TKIP MIC, falling back to s/w\n",
291 __func__);
292 key->wk_flags |= IEEE80211_KEY_SWMIC;
293 }
294
295 /*
296 * Bind cipher to key instance. Note we do this
297 * after checking the device capabilities so the
298 * cipher module can optimize space usage based on
299 * whether or not it needs to do the cipher work.
300 */
301 if (key->wk_cipher != cip || key->wk_flags != oflags) {
302again:
303 keyctx = cip->ic_attach(ic, key);
304 if (keyctx == NULL) {
305 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
306 "%s: unable to attach cipher %s\n",
307 __func__, cip->ic_name);
308 key->wk_flags = oflags; /* restore old flags */
309 ic->ic_stats.is_crypto_attachfail++;
310 return 0;
311 }
312 cipher_detach(key);
313 key->wk_cipher = cip; /* XXX refcnt? */
314 key->wk_private = keyctx;
315 }
316
317 /*
318 * Ask the driver for a key index if we don't have one.
319 * Note that entries in the global key table always have
320 * an index; this means it's safe to call this routine
321 * for these entries just to setup the reference to the
322 * cipher template. Note also that when using software
323 * crypto we also call the driver to give us a key index.
324 */
325 if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
326 key->wk_keyix = dev_key_alloc(ic, key);
327 if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
328 /*
329 * Driver has no room; fallback to doing crypto
330 * in the host. We change the flags and start the
331 * procedure over. If we get back here then there's
332 * no hope and we bail. Note that this can leave
333 * the key in a inconsistent state if the caller
334 * continues to use it.
335 */
336 if ((key->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) {
337 ic->ic_stats.is_crypto_swfallback++;
338 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
339 "%s: no h/w resources for cipher %s, "
340 "falling back to s/w\n", __func__,
341 cip->ic_name);
342 oflags = key->wk_flags;
343 key->wk_flags |= IEEE80211_KEY_SWCRYPT;
344 if (cipher == IEEE80211_CIPHER_TKIP)
345 key->wk_flags |= IEEE80211_KEY_SWMIC;
346 goto again;
347 }
348 ic->ic_stats.is_crypto_keyfail++;
349 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
350 "%s: unable to setup cipher %s\n",
351 __func__, cip->ic_name);
352 return 0;
353 }
354 }
355 return 1;
356#undef N
357}
358
359/*
360 * Remove the key (no locking, for internal use).
361 */
362static int
363_ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key)
364{
365 u_int16_t keyix;
366
367 KASSERT(key->wk_cipher != NULL, ("No cipher!"));
368
369 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
370 "%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n",
371 __func__, key->wk_cipher->ic_name,
372 key->wk_keyix, key->wk_flags,
373 key->wk_keyrsc, key->wk_keytsc, key->wk_keylen);
374
375 keyix = key->wk_keyix;
376 if (keyix != IEEE80211_KEYIX_NONE) {
377 /*
378 * Remove hardware entry.
379 */
380 /* XXX key cache */
381 if (!dev_key_delete(ic, key)) {
382 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
383 "%s: driver did not delete key index %u\n",
384 __func__, keyix);
385 ic->ic_stats.is_crypto_delkey++;
386 /* XXX recovery? */
387 }
388 }
389 cipher_detach(key);
390 memset(key, 0, sizeof(*key));
391 key->wk_cipher = &ieee80211_cipher_none;
392 key->wk_private = cipher_attach(ic, key);
393 /* NB: cannot depend on key index to decide this */
394 if (&ic->ic_nw_keys[0] <= key &&
395 key < &ic->ic_nw_keys[IEEE80211_WEP_NKID])
396 key->wk_keyix = keyix; /* preserve shared key state */
397 else
398 key->wk_keyix = IEEE80211_KEYIX_NONE;
399 return 1;
400}
401
402/*
403 * Remove the specified key.
404 */
405int
406ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key)
407{
408 int status;
409
410 ieee80211_key_update_begin(ic);
411 status = _ieee80211_crypto_delkey(ic, key);
412 ieee80211_key_update_end(ic);
413 return status;
414}
415
416/*
417 * Clear the global key table.
418 */
419void
420ieee80211_crypto_delglobalkeys(struct ieee80211com *ic)
421{
422 int i;
423
424 ieee80211_key_update_begin(ic);
425 for (i = 0; i < IEEE80211_WEP_NKID; i++)
426 (void) _ieee80211_crypto_delkey(ic, &ic->ic_nw_keys[i]);
427 ieee80211_key_update_end(ic);
428}
429
430/*
431 * Set the contents of the specified key.
432 *
433 * Locking must be handled by the caller using:
434 * ieee80211_key_update_begin(ic);
435 * ieee80211_key_update_end(ic);
436 */
437int
438ieee80211_crypto_setkey(struct ieee80211com *ic, struct ieee80211_key *key,
439 const u_int8_t macaddr[IEEE80211_ADDR_LEN])
440{
441 const struct ieee80211_cipher *cip = key->wk_cipher;
442
443 KASSERT(cip != NULL, ("No cipher!"));
444
445 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
446 "%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n",
447 __func__, cip->ic_name, key->wk_keyix,
448 key->wk_flags, ether_sprintf(macaddr),
449 key->wk_keyrsc, key->wk_keytsc, key->wk_keylen);
450
451 /*
452 * Give cipher a chance to validate key contents.
453 * XXX should happen before modifying state.
454 */
455 if (!cip->ic_setkey(key)) {
456 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
457 "%s: cipher %s rejected key index %u len %u flags 0x%x\n",
458 __func__, cip->ic_name, key->wk_keyix,
459 key->wk_keylen, key->wk_flags);
460 ic->ic_stats.is_crypto_setkey_cipher++;
461 return 0;
462 }
463 if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
464 /* XXX nothing allocated, should not happen */
465 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
466 "%s: no key index; should not happen!\n", __func__);
467 ic->ic_stats.is_crypto_setkey_nokey++;
468 return 0;
469 }
470 return dev_key_set(ic, key, macaddr);
471}
472
473/*
474 * Add privacy headers appropriate for the specified key.
475 */
476struct ieee80211_key *
477ieee80211_crypto_encap(struct ieee80211com *ic,
478 struct ieee80211_node *ni, struct mbuf *m)
479{
480 struct ieee80211_key *k;
481 struct ieee80211_frame *wh;
482 const struct ieee80211_cipher *cip;
483 u_int8_t keyix;
484
485 /*
486 * Multicast traffic always uses the multicast key.
487 * Otherwise if a unicast key is set we use that and
488 * it is always key index 0. When no unicast key is
489 * set we fall back to the default transmit key.
490 */
491 wh = mtod(m, struct ieee80211_frame *);
492 if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
493 ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none) {
494 if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE) {
495 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
496 "[%s] no default transmit key (%s) deftxkey %u\n",
497 ether_sprintf(wh->i_addr1), __func__,
498 ic->ic_def_txkey);
499 ic->ic_stats.is_tx_nodefkey++;
500 return NULL;
501 }
502 keyix = ic->ic_def_txkey;
503 k = &ic->ic_nw_keys[ic->ic_def_txkey];
504 } else {
505 keyix = 0;
506 k = &ni->ni_ucastkey;
507 }
508 cip = k->wk_cipher;
509 return (cip->ic_encap(k, m, keyix<<6) ? k : NULL);
510}
511
512/*
513 * Validate and strip privacy headers (and trailer) for a
514 * received frame that has the WEP/Privacy bit set.
515 */
516struct ieee80211_key *
517ieee80211_crypto_decap(struct ieee80211com *ic,
518 struct ieee80211_node *ni, struct mbuf *m)
519{
520#define IEEE80211_WEP_HDRLEN (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
521#define IEEE80211_WEP_MINLEN \
522 (sizeof(struct ieee80211_frame) + ETHER_HDR_LEN + \
523 IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN)
524 struct ieee80211_key *k;
525 struct ieee80211_frame *wh;
526 const struct ieee80211_cipher *cip;
527 const u_int8_t *ivp;
528 u_int8_t keyid;
529 int hdrlen;
530
531 /* NB: this minimum size data frame could be bigger */
532 if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) {
533 IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY,
534 "%s: WEP data frame too short, len %u\n",
535 __func__, m->m_pkthdr.len);
536 ic->ic_stats.is_rx_tooshort++; /* XXX need unique stat? */
537 return NULL;
538 }
539
540 /*
541 * Locate the key. If unicast and there is no unicast
542 * key then we fall back to the key id in the header.
543 * This assumes unicast keys are only configured when
544 * the key id in the header is meaningless (typically 0).
545 */
546 wh = mtod(m, struct ieee80211_frame *);
547 hdrlen = ieee80211_hdrsize(wh);
548 ivp = mtod(m, const u_int8_t *) + hdrlen; /* XXX contig */
549 keyid = ivp[IEEE80211_WEP_IVLEN];
550 if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
551 ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none)
552 k = &ic->ic_nw_keys[keyid >> 6];
553 else
554 k = &ni->ni_ucastkey;
555
556 /*
557 * Insure crypto header is contiguous for all decap work.
558 */
559 cip = k->wk_cipher;
560 if (m->m_len < hdrlen + cip->ic_header &&
561 (m = m_pullup(m, hdrlen + cip->ic_header)) == NULL) {
562 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
563 "[%s] unable to pullup %s header\n",
564 ether_sprintf(wh->i_addr2), cip->ic_name);
565 ic->ic_stats.is_rx_wepfail++; /* XXX */
566 return 0;
567 }
568
569 return (cip->ic_decap(k, m) ? k : NULL);
570#undef IEEE80211_WEP_MINLEN
571#undef IEEE80211_WEP_HDRLEN
572}
| 35
36/*
37 * IEEE 802.11 generic crypto support.
38 */
39#include <sys/param.h>
40#include <sys/mbuf.h>
41
42#include <sys/socket.h>
43
44#include <net/if.h>
45#include <net/if_media.h>
46#include <net/ethernet.h> /* XXX ETHER_HDR_LEN */
47
48#include <net80211/ieee80211_var.h>
49
50/*
51 * Table of registered cipher modules.
52 */
53static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];
54
55static int _ieee80211_crypto_delkey(struct ieee80211com *,
56 struct ieee80211_key *);
57
58/*
59 * Default "null" key management routines.
60 */
61static int
62null_key_alloc(struct ieee80211com *ic, const struct ieee80211_key *k)
63{
64 return IEEE80211_KEYIX_NONE;
65}
66static int
67null_key_delete(struct ieee80211com *ic, const struct ieee80211_key *k)
68{
69 return 1;
70}
71static int
72null_key_set(struct ieee80211com *ic, const struct ieee80211_key *k,
73 const u_int8_t mac[IEEE80211_ADDR_LEN])
74{
75 return 1;
76}
77static void null_key_update(struct ieee80211com *ic) {}
78
79/*
80 * Write-arounds for common operations.
81 */
82static __inline void
83cipher_detach(struct ieee80211_key *key)
84{
85 key->wk_cipher->ic_detach(key);
86}
87
88static __inline void *
89cipher_attach(struct ieee80211com *ic, struct ieee80211_key *key)
90{
91 return key->wk_cipher->ic_attach(ic, key);
92}
93
94/*
95 * Wrappers for driver key management methods.
96 */
97static __inline int
98dev_key_alloc(struct ieee80211com *ic,
99 const struct ieee80211_key *key)
100{
101 return ic->ic_crypto.cs_key_alloc(ic, key);
102}
103
104static __inline int
105dev_key_delete(struct ieee80211com *ic,
106 const struct ieee80211_key *key)
107{
108 return ic->ic_crypto.cs_key_delete(ic, key);
109}
110
111static __inline int
112dev_key_set(struct ieee80211com *ic, const struct ieee80211_key *key,
113 const u_int8_t mac[IEEE80211_ADDR_LEN])
114{
115 return ic->ic_crypto.cs_key_set(ic, key, mac);
116}
117
118/*
119 * Setup crypto support.
120 */
121void
122ieee80211_crypto_attach(struct ieee80211com *ic)
123{
124 struct ieee80211_crypto_state *cs = &ic->ic_crypto;
125 int i;
126
127 /* NB: we assume everything is pre-zero'd */
128 cs->cs_def_txkey = IEEE80211_KEYIX_NONE;
129 ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
130 for (i = 0; i < IEEE80211_WEP_NKID; i++)
131 ieee80211_crypto_resetkey(ic, &cs->cs_nw_keys[i], i);
132 /*
133 * Initialize the driver key support routines to noop entries.
134 * This is useful especially for the cipher test modules.
135 */
136 cs->cs_key_alloc = null_key_alloc;
137 cs->cs_key_set = null_key_set;
138 cs->cs_key_delete = null_key_delete;
139 cs->cs_key_update_begin = null_key_update;
140 cs->cs_key_update_end = null_key_update;
141}
142
143/*
144 * Teardown crypto support.
145 */
146void
147ieee80211_crypto_detach(struct ieee80211com *ic)
148{
149 ieee80211_crypto_delglobalkeys(ic);
150}
151
152/*
153 * Register a crypto cipher module.
154 */
155void
156ieee80211_crypto_register(const struct ieee80211_cipher *cip)
157{
158 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
159 printf("%s: cipher %s has an invalid cipher index %u\n",
160 __func__, cip->ic_name, cip->ic_cipher);
161 return;
162 }
163 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
164 printf("%s: cipher %s registered with a different template\n",
165 __func__, cip->ic_name);
166 return;
167 }
168 ciphers[cip->ic_cipher] = cip;
169}
170
171/*
172 * Unregister a crypto cipher module.
173 */
174void
175ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
176{
177 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
178 printf("%s: cipher %s has an invalid cipher index %u\n",
179 __func__, cip->ic_name, cip->ic_cipher);
180 return;
181 }
182 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
183 printf("%s: cipher %s registered with a different template\n",
184 __func__, cip->ic_name);
185 return;
186 }
187 /* NB: don't complain about not being registered */
188 /* XXX disallow if references */
189 ciphers[cip->ic_cipher] = NULL;
190}
191
192int
193ieee80211_crypto_available(u_int cipher)
194{
195 return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL;
196}
197
198/* XXX well-known names! */
199static const char *cipher_modnames[] = {
200 "wlan_wep", /* IEEE80211_CIPHER_WEP */
201 "wlan_tkip", /* IEEE80211_CIPHER_TKIP */
202 "wlan_aes_ocb", /* IEEE80211_CIPHER_AES_OCB */
203 "wlan_ccmp", /* IEEE80211_CIPHER_AES_CCM */
204 "wlan_ckip", /* IEEE80211_CIPHER_CKIP */
205};
206
207/*
208 * Establish a relationship between the specified key and cipher
209 * and, if not a global key, allocate a hardware index from the
210 * driver. Note that we may be called for global keys but they
211 * should have a key index already setup so the only work done
212 * is to setup the cipher reference.
213 *
214 * This must be the first call applied to a key; all the other key
215 * routines assume wk_cipher is setup.
216 *
217 * Locking must be handled by the caller using:
218 * ieee80211_key_update_begin(ic);
219 * ieee80211_key_update_end(ic);
220 */
221int
222ieee80211_crypto_newkey(struct ieee80211com *ic,
223 int cipher, struct ieee80211_key *key)
224{
225#define N(a) (sizeof(a) / sizeof(a[0]))
226 const struct ieee80211_cipher *cip;
227 void *keyctx;
228 int oflags;
229
230 /*
231 * Validate cipher and set reference to cipher routines.
232 */
233 if (cipher >= IEEE80211_CIPHER_MAX) {
234 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
235 "%s: invalid cipher %u\n", __func__, cipher);
236 ic->ic_stats.is_crypto_badcipher++;
237 return 0;
238 }
239 cip = ciphers[cipher];
240 if (cip == NULL) {
241 /*
242 * Auto-load cipher module if we have a well-known name
243 * for it. It might be better to use string names rather
244 * than numbers and craft a module name based on the cipher
245 * name; e.g. wlan_cipher_<cipher-name>.
246 */
247 if (cipher < N(cipher_modnames)) {
248 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
249 "%s: unregistered cipher %u, load module %s\n",
250 __func__, cipher, cipher_modnames[cipher]);
251 ieee80211_load_module(cipher_modnames[cipher]);
252 /*
253 * If cipher module loaded it should immediately
254 * call ieee80211_crypto_register which will fill
255 * in the entry in the ciphers array.
256 */
257 cip = ciphers[cipher];
258 }
259 if (cip == NULL) {
260 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
261 "%s: unable to load cipher %u, module %s\n",
262 __func__, cipher,
263 cipher < N(cipher_modnames) ?
264 cipher_modnames[cipher] : "<unknown>");
265 ic->ic_stats.is_crypto_nocipher++;
266 return 0;
267 }
268 }
269
270 oflags = key->wk_flags;
271 /*
272 * If the hardware does not support the cipher then
273 * fallback to a host-based implementation.
274 */
275 key->wk_flags &= ~(IEEE80211_KEY_SWCRYPT|IEEE80211_KEY_SWMIC);
276 if ((ic->ic_caps & (1<<cipher)) == 0) {
277 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
278 "%s: no h/w support for cipher %s, falling back to s/w\n",
279 __func__, cip->ic_name);
280 key->wk_flags |= IEEE80211_KEY_SWCRYPT;
281 }
282 /*
283 * Hardware TKIP with software MIC is an important
284 * combination; we handle it by flagging each key,
285 * the cipher modules honor it.
286 */
287 if (cipher == IEEE80211_CIPHER_TKIP &&
288 (ic->ic_caps & IEEE80211_C_TKIPMIC) == 0) {
289 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
290 "%s: no h/w support for TKIP MIC, falling back to s/w\n",
291 __func__);
292 key->wk_flags |= IEEE80211_KEY_SWMIC;
293 }
294
295 /*
296 * Bind cipher to key instance. Note we do this
297 * after checking the device capabilities so the
298 * cipher module can optimize space usage based on
299 * whether or not it needs to do the cipher work.
300 */
301 if (key->wk_cipher != cip || key->wk_flags != oflags) {
302again:
303 keyctx = cip->ic_attach(ic, key);
304 if (keyctx == NULL) {
305 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
306 "%s: unable to attach cipher %s\n",
307 __func__, cip->ic_name);
308 key->wk_flags = oflags; /* restore old flags */
309 ic->ic_stats.is_crypto_attachfail++;
310 return 0;
311 }
312 cipher_detach(key);
313 key->wk_cipher = cip; /* XXX refcnt? */
314 key->wk_private = keyctx;
315 }
316
317 /*
318 * Ask the driver for a key index if we don't have one.
319 * Note that entries in the global key table always have
320 * an index; this means it's safe to call this routine
321 * for these entries just to setup the reference to the
322 * cipher template. Note also that when using software
323 * crypto we also call the driver to give us a key index.
324 */
325 if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
326 key->wk_keyix = dev_key_alloc(ic, key);
327 if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
328 /*
329 * Driver has no room; fallback to doing crypto
330 * in the host. We change the flags and start the
331 * procedure over. If we get back here then there's
332 * no hope and we bail. Note that this can leave
333 * the key in a inconsistent state if the caller
334 * continues to use it.
335 */
336 if ((key->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) {
337 ic->ic_stats.is_crypto_swfallback++;
338 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
339 "%s: no h/w resources for cipher %s, "
340 "falling back to s/w\n", __func__,
341 cip->ic_name);
342 oflags = key->wk_flags;
343 key->wk_flags |= IEEE80211_KEY_SWCRYPT;
344 if (cipher == IEEE80211_CIPHER_TKIP)
345 key->wk_flags |= IEEE80211_KEY_SWMIC;
346 goto again;
347 }
348 ic->ic_stats.is_crypto_keyfail++;
349 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
350 "%s: unable to setup cipher %s\n",
351 __func__, cip->ic_name);
352 return 0;
353 }
354 }
355 return 1;
356#undef N
357}
358
359/*
360 * Remove the key (no locking, for internal use).
361 */
362static int
363_ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key)
364{
365 u_int16_t keyix;
366
367 KASSERT(key->wk_cipher != NULL, ("No cipher!"));
368
369 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
370 "%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n",
371 __func__, key->wk_cipher->ic_name,
372 key->wk_keyix, key->wk_flags,
373 key->wk_keyrsc, key->wk_keytsc, key->wk_keylen);
374
375 keyix = key->wk_keyix;
376 if (keyix != IEEE80211_KEYIX_NONE) {
377 /*
378 * Remove hardware entry.
379 */
380 /* XXX key cache */
381 if (!dev_key_delete(ic, key)) {
382 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
383 "%s: driver did not delete key index %u\n",
384 __func__, keyix);
385 ic->ic_stats.is_crypto_delkey++;
386 /* XXX recovery? */
387 }
388 }
389 cipher_detach(key);
390 memset(key, 0, sizeof(*key));
391 key->wk_cipher = &ieee80211_cipher_none;
392 key->wk_private = cipher_attach(ic, key);
393 /* NB: cannot depend on key index to decide this */
394 if (&ic->ic_nw_keys[0] <= key &&
395 key < &ic->ic_nw_keys[IEEE80211_WEP_NKID])
396 key->wk_keyix = keyix; /* preserve shared key state */
397 else
398 key->wk_keyix = IEEE80211_KEYIX_NONE;
399 return 1;
400}
401
402/*
403 * Remove the specified key.
404 */
405int
406ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key)
407{
408 int status;
409
410 ieee80211_key_update_begin(ic);
411 status = _ieee80211_crypto_delkey(ic, key);
412 ieee80211_key_update_end(ic);
413 return status;
414}
415
416/*
417 * Clear the global key table.
418 */
419void
420ieee80211_crypto_delglobalkeys(struct ieee80211com *ic)
421{
422 int i;
423
424 ieee80211_key_update_begin(ic);
425 for (i = 0; i < IEEE80211_WEP_NKID; i++)
426 (void) _ieee80211_crypto_delkey(ic, &ic->ic_nw_keys[i]);
427 ieee80211_key_update_end(ic);
428}
429
430/*
431 * Set the contents of the specified key.
432 *
433 * Locking must be handled by the caller using:
434 * ieee80211_key_update_begin(ic);
435 * ieee80211_key_update_end(ic);
436 */
437int
438ieee80211_crypto_setkey(struct ieee80211com *ic, struct ieee80211_key *key,
439 const u_int8_t macaddr[IEEE80211_ADDR_LEN])
440{
441 const struct ieee80211_cipher *cip = key->wk_cipher;
442
443 KASSERT(cip != NULL, ("No cipher!"));
444
445 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
446 "%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n",
447 __func__, cip->ic_name, key->wk_keyix,
448 key->wk_flags, ether_sprintf(macaddr),
449 key->wk_keyrsc, key->wk_keytsc, key->wk_keylen);
450
451 /*
452 * Give cipher a chance to validate key contents.
453 * XXX should happen before modifying state.
454 */
455 if (!cip->ic_setkey(key)) {
456 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
457 "%s: cipher %s rejected key index %u len %u flags 0x%x\n",
458 __func__, cip->ic_name, key->wk_keyix,
459 key->wk_keylen, key->wk_flags);
460 ic->ic_stats.is_crypto_setkey_cipher++;
461 return 0;
462 }
463 if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
464 /* XXX nothing allocated, should not happen */
465 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
466 "%s: no key index; should not happen!\n", __func__);
467 ic->ic_stats.is_crypto_setkey_nokey++;
468 return 0;
469 }
470 return dev_key_set(ic, key, macaddr);
471}
472
473/*
474 * Add privacy headers appropriate for the specified key.
475 */
476struct ieee80211_key *
477ieee80211_crypto_encap(struct ieee80211com *ic,
478 struct ieee80211_node *ni, struct mbuf *m)
479{
480 struct ieee80211_key *k;
481 struct ieee80211_frame *wh;
482 const struct ieee80211_cipher *cip;
483 u_int8_t keyix;
484
485 /*
486 * Multicast traffic always uses the multicast key.
487 * Otherwise if a unicast key is set we use that and
488 * it is always key index 0. When no unicast key is
489 * set we fall back to the default transmit key.
490 */
491 wh = mtod(m, struct ieee80211_frame *);
492 if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
493 ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none) {
494 if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE) {
495 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
496 "[%s] no default transmit key (%s) deftxkey %u\n",
497 ether_sprintf(wh->i_addr1), __func__,
498 ic->ic_def_txkey);
499 ic->ic_stats.is_tx_nodefkey++;
500 return NULL;
501 }
502 keyix = ic->ic_def_txkey;
503 k = &ic->ic_nw_keys[ic->ic_def_txkey];
504 } else {
505 keyix = 0;
506 k = &ni->ni_ucastkey;
507 }
508 cip = k->wk_cipher;
509 return (cip->ic_encap(k, m, keyix<<6) ? k : NULL);
510}
511
512/*
513 * Validate and strip privacy headers (and trailer) for a
514 * received frame that has the WEP/Privacy bit set.
515 */
516struct ieee80211_key *
517ieee80211_crypto_decap(struct ieee80211com *ic,
518 struct ieee80211_node *ni, struct mbuf *m)
519{
520#define IEEE80211_WEP_HDRLEN (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
521#define IEEE80211_WEP_MINLEN \
522 (sizeof(struct ieee80211_frame) + ETHER_HDR_LEN + \
523 IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN)
524 struct ieee80211_key *k;
525 struct ieee80211_frame *wh;
526 const struct ieee80211_cipher *cip;
527 const u_int8_t *ivp;
528 u_int8_t keyid;
529 int hdrlen;
530
531 /* NB: this minimum size data frame could be bigger */
532 if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) {
533 IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY,
534 "%s: WEP data frame too short, len %u\n",
535 __func__, m->m_pkthdr.len);
536 ic->ic_stats.is_rx_tooshort++; /* XXX need unique stat? */
537 return NULL;
538 }
539
540 /*
541 * Locate the key. If unicast and there is no unicast
542 * key then we fall back to the key id in the header.
543 * This assumes unicast keys are only configured when
544 * the key id in the header is meaningless (typically 0).
545 */
546 wh = mtod(m, struct ieee80211_frame *);
547 hdrlen = ieee80211_hdrsize(wh);
548 ivp = mtod(m, const u_int8_t *) + hdrlen; /* XXX contig */
549 keyid = ivp[IEEE80211_WEP_IVLEN];
550 if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
551 ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none)
552 k = &ic->ic_nw_keys[keyid >> 6];
553 else
554 k = &ni->ni_ucastkey;
555
556 /*
557 * Insure crypto header is contiguous for all decap work.
558 */
559 cip = k->wk_cipher;
560 if (m->m_len < hdrlen + cip->ic_header &&
561 (m = m_pullup(m, hdrlen + cip->ic_header)) == NULL) {
562 IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
563 "[%s] unable to pullup %s header\n",
564 ether_sprintf(wh->i_addr2), cip->ic_name);
565 ic->ic_stats.is_rx_wepfail++; /* XXX */
566 return 0;
567 }
568
569 return (cip->ic_decap(k, m) ? k : NULL);
570#undef IEEE80211_WEP_MINLEN
571#undef IEEE80211_WEP_HDRLEN
572}
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