1 /*
2 * Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 */
19
20 FILE_LICENCE ( GPL2_OR_LATER );
21
22 #include <ipxe/net80211.h>
23 #include <ipxe/sec80211.h>
24 #include <ipxe/wpa.h>
25 #include <ipxe/eapol.h>
26 #include <ipxe/crypto.h>
27 #include <ipxe/arc4.h>
28 #include <ipxe/crc32.h>
29 #include <ipxe/sha1.h>
30 #include <ipxe/hmac.h>
31 #include <ipxe/list.h>
32 #include <ipxe/ethernet.h>
33 #include <ipxe/rbg.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <errno.h>
37 #include <byteswap.h>
38
39 /** @file
40 *
41 * Handler for the aspects of WPA handshaking that are independent of
42 * 802.1X/PSK or TKIP/CCMP; this mostly involves the 4-Way Handshake.
43 */
44
45 /** List of WPA contexts in active use. */
46 struct list_head wpa_contexts = LIST_HEAD_INIT ( wpa_contexts );
47
48
49 /**
50 * Return an error code and deauthenticate
51 *
52 * @v ctx WPA common context
53 * @v rc Return status code
54 * @ret rc The passed return status code
55 */
wpa_fail(struct wpa_common_ctx * ctx,int rc)56 static int wpa_fail ( struct wpa_common_ctx *ctx, int rc )
57 {
58 net80211_deauthenticate ( ctx->dev, rc );
59 return rc;
60 }
61
62
63 /**
64 * Find a cryptosystem handler structure from a crypto ID
65 *
66 * @v crypt Cryptosystem ID
67 * @ret crypto Cryptosystem handler structure
68 *
69 * If support for @a crypt is not compiled in to iPXE, or if @a crypt
70 * is NET80211_CRYPT_UNKNOWN, returns @c NULL.
71 */
72 static struct net80211_crypto *
wpa_find_cryptosystem(enum net80211_crypto_alg crypt)73 wpa_find_cryptosystem ( enum net80211_crypto_alg crypt )
74 {
75 struct net80211_crypto *crypto;
76
77 for_each_table_entry ( crypto, NET80211_CRYPTOS ) {
78 if ( crypto->algorithm == crypt )
79 return crypto;
80 }
81
82 return NULL;
83 }
84
85
86 /**
87 * Find WPA key integrity and encryption handler from key version field
88 *
89 * @v ver Version bits of EAPOL-Key info field
90 * @ret kie Key integrity and encryption handler
91 */
wpa_find_kie(int version)92 struct wpa_kie * wpa_find_kie ( int version )
93 {
94 struct wpa_kie *kie;
95
96 for_each_table_entry ( kie, WPA_KIES ) {
97 if ( kie->version == version )
98 return kie;
99 }
100
101 return NULL;
102 }
103
104
105 /**
106 * Construct RSN or WPA information element
107 *
108 * @v dev 802.11 device
109 * @ret ie_ret RSN or WPA information element
110 * @ret rc Return status code
111 *
112 * This function allocates, fills, and returns a RSN or WPA
113 * information element suitable for including in an association
114 * request frame to the network identified by @c dev->associating.
115 * If it is impossible to construct an information element consistent
116 * with iPXE's capabilities that is compatible with that network, or
117 * if none should be sent because that network's beacon included no
118 * security information, returns an error indication and leaves
119 * @a ie_ret unchanged.
120 *
121 * The returned IE will be of the same type (RSN or WPA) as was
122 * included in the beacon for the network it is destined for.
123 */
wpa_make_rsn_ie(struct net80211_device * dev,union ieee80211_ie ** ie_ret)124 int wpa_make_rsn_ie ( struct net80211_device *dev, union ieee80211_ie **ie_ret )
125 {
126 u8 *rsn, *rsn_end;
127 int is_rsn;
128 u32 group_cipher;
129 enum net80211_crypto_alg gcrypt;
130 int ie_len;
131 u8 *iep;
132 struct ieee80211_ie_rsn *ie;
133 struct ieee80211_frame *hdr;
134 struct ieee80211_beacon *beacon;
135
136 if ( ! dev->associating ) {
137 DBG ( "WPA: Can't make RSN IE for a non-associating device\n" );
138 return -EINVAL;
139 }
140
141 hdr = dev->associating->beacon->data;
142 beacon = ( struct ieee80211_beacon * ) hdr->data;
143 rsn = sec80211_find_rsn ( beacon->info_element,
144 dev->associating->beacon->tail, &is_rsn,
145 &rsn_end );
146 if ( ! rsn ) {
147 DBG ( "WPA: Can't make RSN IE when we didn't get one\n" );
148 return -EINVAL;
149 }
150
151 rsn += 2; /* skip version */
152 group_cipher = *( u32 * ) rsn;
153 gcrypt = sec80211_rsn_get_net80211_crypt ( group_cipher );
154
155 if ( ! wpa_find_cryptosystem ( gcrypt ) ||
156 ! wpa_find_cryptosystem ( dev->associating->crypto ) ) {
157 DBG ( "WPA: No support for (GC:%d, PC:%d)\n",
158 gcrypt, dev->associating->crypto );
159 return -ENOTSUP;
160 }
161
162 /* Everything looks good - make our IE. */
163
164 /* WPA IEs need 4 more bytes for the OUI+type */
165 ie_len = ieee80211_rsn_size ( 1, 1, 0, is_rsn ) + ( 4 * ! is_rsn );
166 iep = malloc ( ie_len );
167 if ( ! iep )
168 return -ENOMEM;
169
170 *ie_ret = ( union ieee80211_ie * ) iep;
171
172 /* Store ID and length bytes. */
173 *iep++ = ( is_rsn ? IEEE80211_IE_RSN : IEEE80211_IE_VENDOR );
174 *iep++ = ie_len - 2;
175
176 /* Store OUI+type for WPA IEs. */
177 if ( ! is_rsn ) {
178 *( u32 * ) iep = IEEE80211_WPA_OUI_VEN;
179 iep += 4;
180 }
181
182 /* If this is a WPA IE, the id and len bytes in the
183 ieee80211_ie_rsn structure will not be valid, but by doing
184 the cast we can fill all the other fields much more
185 readily. */
186
187 ie = ( struct ieee80211_ie_rsn * ) ( iep - 2 );
188 ie->version = IEEE80211_RSN_VERSION;
189 ie->group_cipher = group_cipher;
190 ie->pairwise_count = 1;
191 ie->pairwise_cipher[0] =
192 sec80211_rsn_get_crypto_desc ( dev->associating->crypto,
193 is_rsn );
194 ie->akm_count = 1;
195 ie->akm_list[0] =
196 sec80211_rsn_get_akm_desc ( dev->associating->handshaking,
197 is_rsn );
198 if ( is_rsn ) {
199 ie->rsn_capab = 0;
200 ie->pmkid_count = 0;
201 }
202
203 return 0;
204 }
205
206
207 /**
208 * Set up generic WPA support to handle 4-Way Handshake
209 *
210 * @v dev 802.11 device
211 * @v ctx WPA common context
212 * @v pmk Pairwise Master Key to use for session
213 * @v pmk_len Length of PMK, almost always 32
214 * @ret rc Return status code
215 */
wpa_start(struct net80211_device * dev,struct wpa_common_ctx * ctx,const void * pmk,size_t pmk_len)216 int wpa_start ( struct net80211_device *dev, struct wpa_common_ctx *ctx,
217 const void *pmk, size_t pmk_len )
218 {
219 struct io_buffer *iob;
220 struct ieee80211_frame *hdr;
221 struct ieee80211_beacon *beacon;
222 u8 *ap_rsn_ie = NULL, *ap_rsn_ie_end;
223
224 if ( ! dev->rsn_ie || ! dev->associating )
225 return -EINVAL;
226
227 ctx->dev = dev;
228 memcpy ( ctx->pmk, pmk, ctx->pmk_len = pmk_len );
229 ctx->state = WPA_READY;
230 ctx->replay = ~0ULL;
231
232 iob = dev->associating->beacon;
233 hdr = iob->data;
234 beacon = ( struct ieee80211_beacon * ) hdr->data;
235 ap_rsn_ie = sec80211_find_rsn ( beacon->info_element, iob->tail,
236 &ctx->ap_rsn_is_rsn, &ap_rsn_ie_end );
237 if ( ap_rsn_ie ) {
238 ctx->ap_rsn_ie = malloc ( ap_rsn_ie_end - ap_rsn_ie );
239 if ( ! ctx->ap_rsn_ie )
240 return -ENOMEM;
241 memcpy ( ctx->ap_rsn_ie, ap_rsn_ie, ap_rsn_ie_end - ap_rsn_ie );
242 ctx->ap_rsn_ie_len = ap_rsn_ie_end - ap_rsn_ie;
243 } else {
244 return -ENOENT;
245 }
246
247 ctx->crypt = dev->associating->crypto;
248 ctx->gcrypt = NET80211_CRYPT_UNKNOWN;
249
250 list_add_tail ( &ctx->list, &wpa_contexts );
251 return 0;
252 }
253
254
255 /**
256 * Disable handling of received WPA handshake frames
257 *
258 * @v dev 802.11 device
259 */
wpa_stop(struct net80211_device * dev)260 void wpa_stop ( struct net80211_device *dev )
261 {
262 struct wpa_common_ctx *ctx, *tmp;
263
264 list_for_each_entry_safe ( ctx, tmp, &wpa_contexts, list ) {
265 if ( ctx->dev == dev ) {
266 free ( ctx->ap_rsn_ie );
267 ctx->ap_rsn_ie = NULL;
268 list_del ( &ctx->list );
269 }
270 }
271 }
272
273
274 /**
275 * Derive pairwise transient key
276 *
277 * @v ctx WPA common context
278 */
wpa_derive_ptk(struct wpa_common_ctx * ctx)279 static void wpa_derive_ptk ( struct wpa_common_ctx *ctx )
280 {
281 struct {
282 u8 mac1[ETH_ALEN];
283 u8 mac2[ETH_ALEN];
284 u8 nonce1[WPA_NONCE_LEN];
285 u8 nonce2[WPA_NONCE_LEN];
286 } __attribute__ (( packed )) ptk_data;
287
288 /* The addresses and nonces are stored in numerical order (!) */
289
290 if ( memcmp ( ctx->dev->netdev->ll_addr, ctx->dev->bssid,
291 ETH_ALEN ) < 0 ) {
292 memcpy ( ptk_data.mac1, ctx->dev->netdev->ll_addr, ETH_ALEN );
293 memcpy ( ptk_data.mac2, ctx->dev->bssid, ETH_ALEN );
294 } else {
295 memcpy ( ptk_data.mac1, ctx->dev->bssid, ETH_ALEN );
296 memcpy ( ptk_data.mac2, ctx->dev->netdev->ll_addr, ETH_ALEN );
297 }
298
299 if ( memcmp ( ctx->Anonce, ctx->Snonce, WPA_NONCE_LEN ) < 0 ) {
300 memcpy ( ptk_data.nonce1, ctx->Anonce, WPA_NONCE_LEN );
301 memcpy ( ptk_data.nonce2, ctx->Snonce, WPA_NONCE_LEN );
302 } else {
303 memcpy ( ptk_data.nonce1, ctx->Snonce, WPA_NONCE_LEN );
304 memcpy ( ptk_data.nonce2, ctx->Anonce, WPA_NONCE_LEN );
305 }
306
307 DBGC2 ( ctx, "WPA %p A1 %s, A2 %s\n", ctx, eth_ntoa ( ptk_data.mac1 ),
308 eth_ntoa ( ptk_data.mac2 ) );
309 DBGC2 ( ctx, "WPA %p Nonce1, Nonce2:\n", ctx );
310 DBGC2_HD ( ctx, ptk_data.nonce1, WPA_NONCE_LEN );
311 DBGC2_HD ( ctx, ptk_data.nonce2, WPA_NONCE_LEN );
312
313 prf_sha1 ( ctx->pmk, ctx->pmk_len,
314 "Pairwise key expansion",
315 &ptk_data, sizeof ( ptk_data ),
316 &ctx->ptk, sizeof ( ctx->ptk ) );
317
318 DBGC2 ( ctx, "WPA %p PTK:\n", ctx );
319 DBGC2_HD ( ctx, &ctx->ptk, sizeof ( ctx->ptk ) );
320 }
321
322
323 /**
324 * Install pairwise transient key
325 *
326 * @v ctx WPA common context
327 * @v len Key length (16 for CCMP, 32 for TKIP)
328 * @ret rc Return status code
329 */
wpa_install_ptk(struct wpa_common_ctx * ctx,int len)330 static inline int wpa_install_ptk ( struct wpa_common_ctx *ctx, int len )
331 {
332 DBGC ( ctx, "WPA %p: installing %d-byte pairwise transient key\n",
333 ctx, len );
334 DBGC2_HD ( ctx, &ctx->ptk.tk, len );
335
336 return sec80211_install ( &ctx->dev->crypto, ctx->crypt,
337 &ctx->ptk.tk, len, NULL );
338 }
339
340 /**
341 * Install group transient key
342 *
343 * @v ctx WPA common context
344 * @v len Key length (16 for CCMP, 32 for TKIP)
345 * @v rsc Receive sequence counter field in EAPOL-Key packet
346 * @ret rc Return status code
347 */
wpa_install_gtk(struct wpa_common_ctx * ctx,int len,const void * rsc)348 static inline int wpa_install_gtk ( struct wpa_common_ctx *ctx, int len,
349 const void *rsc )
350 {
351 DBGC ( ctx, "WPA %p: installing %d-byte group transient key\n",
352 ctx, len );
353 DBGC2_HD ( ctx, &ctx->gtk.tk, len );
354
355 return sec80211_install ( &ctx->dev->gcrypto, ctx->gcrypt,
356 &ctx->gtk.tk, len, rsc );
357 }
358
359 /**
360 * Search for group transient key, and install it if found
361 *
362 * @v ctx WPA common context
363 * @v ie Pointer to first IE in key data field
364 * @v ie_end Pointer to first byte not in key data field
365 * @v rsc Receive sequence counter field in EAPOL-Key packet
366 * @ret rc Return status code
367 */
wpa_maybe_install_gtk(struct wpa_common_ctx * ctx,union ieee80211_ie * ie,void * ie_end,const void * rsc)368 static int wpa_maybe_install_gtk ( struct wpa_common_ctx *ctx,
369 union ieee80211_ie *ie, void *ie_end,
370 const void *rsc )
371 {
372 struct wpa_kde *kde;
373
374 if ( ! ieee80211_ie_bound ( ie, ie_end ) )
375 return -ENOENT;
376
377 while ( ie ) {
378 if ( ie->id == IEEE80211_IE_VENDOR &&
379 ie->vendor.oui == WPA_KDE_GTK )
380 break;
381
382 ie = ieee80211_next_ie ( ie, ie_end );
383 }
384
385 if ( ! ie )
386 return -ENOENT;
387
388 if ( ie->len - 6u > sizeof ( ctx->gtk.tk ) ) {
389 DBGC ( ctx, "WPA %p: GTK KDE is too long (%d bytes, max %zd)\n",
390 ctx, ie->len - 4, sizeof ( ctx->gtk.tk ) );
391 return -EINVAL;
392 }
393
394 /* XXX We ignore key ID for now. */
395 kde = ( struct wpa_kde * ) ie;
396 memcpy ( &ctx->gtk.tk, &kde->gtk_encap.gtk, kde->len - 6 );
397
398 return wpa_install_gtk ( ctx, kde->len - 6, rsc );
399 }
400
401
402 /**
403 * Allocate I/O buffer for construction of outgoing EAPOL-Key frame
404 *
405 * @v kdlen Maximum number of bytes in the Key Data field
406 * @ret iob Newly allocated I/O buffer
407 *
408 * The returned buffer will have space reserved for the link-layer and
409 * EAPOL headers, and will have @c iob->tail pointing to the start of
410 * the Key Data field. Thus, it is necessary to use iob_put() in
411 * filling the Key Data.
412 */
wpa_alloc_frame(int kdlen)413 static struct io_buffer * wpa_alloc_frame ( int kdlen )
414 {
415 struct io_buffer *ret = alloc_iob ( sizeof ( struct eapol_key_pkt ) +
416 kdlen + EAPOL_HDR_LEN +
417 MAX_LL_HEADER_LEN );
418 if ( ! ret )
419 return NULL;
420
421 iob_reserve ( ret, MAX_LL_HEADER_LEN + EAPOL_HDR_LEN );
422 memset ( iob_put ( ret, sizeof ( struct eapol_key_pkt ) ), 0,
423 sizeof ( struct eapol_key_pkt ) );
424
425 return ret;
426 }
427
428
429 /**
430 * Send EAPOL-Key packet
431 *
432 * @v iob I/O buffer, with sufficient headroom for headers
433 * @v dev 802.11 device
434 * @v kie Key integrity and encryption handler
435 * @v is_rsn If TRUE, handshake uses new RSN format
436 * @ret rc Return status code
437 *
438 * If a KIE is specified, the MIC will be filled in before transmission.
439 */
wpa_send_eapol(struct io_buffer * iob,struct wpa_common_ctx * ctx,struct wpa_kie * kie)440 static int wpa_send_eapol ( struct io_buffer *iob, struct wpa_common_ctx *ctx,
441 struct wpa_kie *kie )
442 {
443 struct eapol_key_pkt *pkt = iob->data;
444 struct eapol_frame *eapol = iob_push ( iob, EAPOL_HDR_LEN );
445
446 pkt->info = htons ( pkt->info );
447 pkt->keysize = htons ( pkt->keysize );
448 pkt->datalen = htons ( pkt->datalen );
449 pkt->replay = cpu_to_be64 ( pkt->replay );
450 eapol->version = EAPOL_THIS_VERSION;
451 eapol->type = EAPOL_TYPE_KEY;
452 eapol->length = htons ( iob->tail - iob->data - sizeof ( *eapol ) );
453
454 memset ( pkt->mic, 0, sizeof ( pkt->mic ) );
455 if ( kie )
456 kie->mic ( &ctx->ptk.kck, eapol, EAPOL_HDR_LEN +
457 sizeof ( *pkt ) + ntohs ( pkt->datalen ),
458 pkt->mic );
459
460 return net_tx ( iob, ctx->dev->netdev, &eapol_protocol,
461 ctx->dev->bssid, ctx->dev->netdev->ll_addr );
462 }
463
464
465 /**
466 * Send second frame in 4-Way Handshake
467 *
468 * @v ctx WPA common context
469 * @v pkt First frame, to which this is a reply
470 * @v is_rsn If TRUE, handshake uses new RSN format
471 * @v kie Key integrity and encryption handler
472 * @ret rc Return status code
473 */
wpa_send_2_of_4(struct wpa_common_ctx * ctx,struct eapol_key_pkt * pkt,int is_rsn,struct wpa_kie * kie)474 static int wpa_send_2_of_4 ( struct wpa_common_ctx *ctx,
475 struct eapol_key_pkt *pkt, int is_rsn,
476 struct wpa_kie *kie )
477 {
478 struct io_buffer *iob = wpa_alloc_frame ( ctx->dev->rsn_ie->len + 2 );
479 struct eapol_key_pkt *npkt;
480
481 if ( ! iob )
482 return -ENOMEM;
483
484 npkt = iob->data;
485 memcpy ( npkt, pkt, sizeof ( *pkt ) );
486 npkt->info &= ~EAPOL_KEY_INFO_KEY_ACK;
487 npkt->info |= EAPOL_KEY_INFO_KEY_MIC;
488 if ( is_rsn )
489 npkt->keysize = 0;
490 memcpy ( npkt->nonce, ctx->Snonce, sizeof ( npkt->nonce ) );
491 npkt->datalen = ctx->dev->rsn_ie->len + 2;
492 memcpy ( iob_put ( iob, npkt->datalen ), ctx->dev->rsn_ie,
493 npkt->datalen );
494
495 DBGC ( ctx, "WPA %p: sending 2/4\n", ctx );
496
497 return wpa_send_eapol ( iob, ctx, kie );
498 }
499
500
501 /**
502 * Handle receipt of first frame in 4-Way Handshake
503 *
504 * @v ctx WPA common context
505 * @v pkt EAPOL-Key packet
506 * @v is_rsn If TRUE, frame uses new RSN format
507 * @v kie Key integrity and encryption handler
508 * @ret rc Return status code
509 */
wpa_handle_1_of_4(struct wpa_common_ctx * ctx,struct eapol_key_pkt * pkt,int is_rsn,struct wpa_kie * kie)510 static int wpa_handle_1_of_4 ( struct wpa_common_ctx *ctx,
511 struct eapol_key_pkt *pkt, int is_rsn,
512 struct wpa_kie *kie )
513 {
514 if ( ctx->state == WPA_WAITING )
515 return -EINVAL;
516
517 ctx->state = WPA_WORKING;
518 memcpy ( ctx->Anonce, pkt->nonce, sizeof ( ctx->Anonce ) );
519 if ( ! ctx->have_Snonce ) {
520 rbg_generate ( NULL, 0, 0, ctx->Snonce,
521 sizeof ( ctx->Snonce ) );
522 ctx->have_Snonce = 1;
523 }
524
525 DBGC ( ctx, "WPA %p: received 1/4, looks OK\n", ctx );
526
527 wpa_derive_ptk ( ctx );
528
529 return wpa_send_2_of_4 ( ctx, pkt, is_rsn, kie );
530 }
531
532
533 /**
534 * Send fourth frame in 4-Way Handshake, or second in Group Key Handshake
535 *
536 * @v ctx WPA common context
537 * @v pkt EAPOL-Key packet for frame to which we're replying
538 * @v is_rsn If TRUE, frame uses new RSN format
539 * @v kie Key integrity and encryption handler
540 * @ret rc Return status code
541 */
wpa_send_final(struct wpa_common_ctx * ctx,struct eapol_key_pkt * pkt,int is_rsn,struct wpa_kie * kie)542 static int wpa_send_final ( struct wpa_common_ctx *ctx,
543 struct eapol_key_pkt *pkt, int is_rsn,
544 struct wpa_kie *kie )
545 {
546 struct io_buffer *iob = wpa_alloc_frame ( 0 );
547 struct eapol_key_pkt *npkt;
548
549 if ( ! iob )
550 return -ENOMEM;
551
552 npkt = iob->data;
553 memcpy ( npkt, pkt, sizeof ( *pkt ) );
554 npkt->info &= ~( EAPOL_KEY_INFO_KEY_ACK | EAPOL_KEY_INFO_INSTALL |
555 EAPOL_KEY_INFO_KEY_ENC );
556 if ( is_rsn )
557 npkt->keysize = 0;
558 memset ( npkt->nonce, 0, sizeof ( npkt->nonce ) );
559 memset ( npkt->iv, 0, sizeof ( npkt->iv ) );
560 npkt->datalen = 0;
561
562 if ( npkt->info & EAPOL_KEY_INFO_TYPE )
563 DBGC ( ctx, "WPA %p: sending 4/4\n", ctx );
564 else
565 DBGC ( ctx, "WPA %p: sending 2/2\n", ctx );
566
567 return wpa_send_eapol ( iob, ctx, kie );
568
569 }
570
571
572 /**
573 * Handle receipt of third frame in 4-Way Handshake
574 *
575 * @v ctx WPA common context
576 * @v pkt EAPOL-Key packet
577 * @v is_rsn If TRUE, frame uses new RSN format
578 * @v kie Key integrity and encryption handler
579 * @ret rc Return status code
580 */
wpa_handle_3_of_4(struct wpa_common_ctx * ctx,struct eapol_key_pkt * pkt,int is_rsn,struct wpa_kie * kie)581 static int wpa_handle_3_of_4 ( struct wpa_common_ctx *ctx,
582 struct eapol_key_pkt *pkt, int is_rsn,
583 struct wpa_kie *kie )
584 {
585 int rc;
586 u8 *this_rsn, *this_rsn_end;
587 u8 *new_rsn, *new_rsn_end;
588 int this_is_rsn, new_is_rsn;
589
590 if ( ctx->state == WPA_WAITING )
591 return -EINVAL;
592
593 ctx->state = WPA_WORKING;
594
595 /* Check nonce */
596 if ( memcmp ( ctx->Anonce, pkt->nonce, WPA_NONCE_LEN ) != 0 ) {
597 DBGC ( ctx, "WPA %p ALERT: nonce mismatch in 3/4\n", ctx );
598 return wpa_fail ( ctx, -EACCES );
599 }
600
601 /* Check RSN IE */
602 this_rsn = sec80211_find_rsn ( ( union ieee80211_ie * ) pkt->data,
603 pkt->data + pkt->datalen,
604 &this_is_rsn, &this_rsn_end );
605 if ( this_rsn )
606 new_rsn = sec80211_find_rsn ( ( union ieee80211_ie * )
607 this_rsn_end,
608 pkt->data + pkt->datalen,
609 &new_is_rsn, &new_rsn_end );
610 else
611 new_rsn = NULL;
612
613 if ( ! ctx->ap_rsn_ie || ! this_rsn ||
614 ctx->ap_rsn_ie_len != ( this_rsn_end - this_rsn ) ||
615 ctx->ap_rsn_is_rsn != this_is_rsn ||
616 memcmp ( ctx->ap_rsn_ie, this_rsn, ctx->ap_rsn_ie_len ) != 0 ) {
617 DBGC ( ctx, "WPA %p ALERT: RSN mismatch in 3/4\n", ctx );
618 DBGC2 ( ctx, "WPA %p RSNs (in 3/4, in beacon):\n", ctx );
619 DBGC2_HD ( ctx, this_rsn, this_rsn_end - this_rsn );
620 DBGC2_HD ( ctx, ctx->ap_rsn_ie, ctx->ap_rsn_ie_len );
621 return wpa_fail ( ctx, -EACCES );
622 }
623
624 /* Don't switch if they just supplied both styles of IE
625 simultaneously; we need two RSN IEs or two WPA IEs to
626 switch ciphers. They'll be immediately consecutive because
627 of ordering guarantees. */
628 if ( new_rsn && this_is_rsn == new_is_rsn ) {
629 struct net80211_wlan *assoc = ctx->dev->associating;
630 DBGC ( ctx, "WPA %p: accommodating bait-and-switch tactics\n",
631 ctx );
632 DBGC2 ( ctx, "WPA %p RSNs (in 3/4+beacon, new in 3/4):\n",
633 ctx );
634 DBGC2_HD ( ctx, this_rsn, this_rsn_end - this_rsn );
635 DBGC2_HD ( ctx, new_rsn, new_rsn_end - new_rsn );
636
637 if ( ( rc = sec80211_detect_ie ( new_is_rsn, new_rsn,
638 new_rsn_end,
639 &assoc->handshaking,
640 &assoc->crypto ) ) != 0 )
641 DBGC ( ctx, "WPA %p: bait-and-switch invalid, staying "
642 "with original request\n", ctx );
643 } else {
644 new_rsn = this_rsn;
645 new_is_rsn = this_is_rsn;
646 new_rsn_end = this_rsn_end;
647 }
648
649 /* Grab group cryptosystem ID */
650 ctx->gcrypt = sec80211_rsn_get_net80211_crypt ( *( u32 * )
651 ( new_rsn + 2 ) );
652
653 /* Check for a GTK, if info field is encrypted */
654 if ( pkt->info & EAPOL_KEY_INFO_KEY_ENC ) {
655 rc = wpa_maybe_install_gtk ( ctx,
656 ( union ieee80211_ie * ) pkt->data,
657 pkt->data + pkt->datalen,
658 pkt->rsc );
659 if ( rc < 0 ) {
660 DBGC ( ctx, "WPA %p did not install GTK in 3/4: %s\n",
661 ctx, strerror ( rc ) );
662 if ( rc != -ENOENT )
663 return wpa_fail ( ctx, rc );
664 }
665 }
666
667 DBGC ( ctx, "WPA %p: received 3/4, looks OK\n", ctx );
668
669 /* Send final message */
670 rc = wpa_send_final ( ctx, pkt, is_rsn, kie );
671 if ( rc < 0 )
672 return wpa_fail ( ctx, rc );
673
674 /* Install PTK */
675 rc = wpa_install_ptk ( ctx, pkt->keysize );
676 if ( rc < 0 ) {
677 DBGC ( ctx, "WPA %p failed to install PTK: %s\n", ctx,
678 strerror ( rc ) );
679 return wpa_fail ( ctx, rc );
680 }
681
682 /* Mark us as needing a new Snonce if we rekey */
683 ctx->have_Snonce = 0;
684
685 /* Done! */
686 ctx->state = WPA_SUCCESS;
687 return 0;
688 }
689
690
691 /**
692 * Handle receipt of first frame in Group Key Handshake
693 *
694 * @v ctx WPA common context
695 * @v pkt EAPOL-Key packet
696 * @v is_rsn If TRUE, frame uses new RSN format
697 * @v kie Key integrity and encryption handler
698 * @ret rc Return status code
699 */
wpa_handle_1_of_2(struct wpa_common_ctx * ctx,struct eapol_key_pkt * pkt,int is_rsn,struct wpa_kie * kie)700 static int wpa_handle_1_of_2 ( struct wpa_common_ctx *ctx,
701 struct eapol_key_pkt *pkt, int is_rsn,
702 struct wpa_kie *kie )
703 {
704 int rc;
705
706 /*
707 * WPA and RSN do this completely differently.
708 *
709 * The idea of encoding the GTK (or PMKID, or various other
710 * things) into a KDE that looks like an information element
711 * is an RSN innovation; old WPA code never encapsulates
712 * things like that. If it looks like an info element, it
713 * really is (for the WPA IE check in frames 2/4 and 3/4). The
714 * "key data encrypted" bit in the info field is also specific
715 * to RSN.
716 *
717 * So from an old WPA host, 3/4 does not contain an
718 * encapsulated GTK. The first frame of the GK handshake
719 * contains it, encrypted, but without a KDE wrapper, and with
720 * the key ID field (which iPXE doesn't use) shoved away in
721 * the reserved bits in the info field, and the TxRx bit
722 * stealing the Install bit's spot.
723 */
724
725 if ( is_rsn && ( pkt->info & EAPOL_KEY_INFO_KEY_ENC ) ) {
726 rc = wpa_maybe_install_gtk ( ctx,
727 ( union ieee80211_ie * ) pkt->data,
728 pkt->data + pkt->datalen,
729 pkt->rsc );
730 if ( rc < 0 ) {
731 DBGC ( ctx, "WPA %p: failed to install GTK in 1/2: "
732 "%s\n", ctx, strerror ( rc ) );
733 return wpa_fail ( ctx, rc );
734 }
735 } else {
736 rc = kie->decrypt ( &ctx->ptk.kek, pkt->iv, pkt->data,
737 &pkt->datalen );
738 if ( rc < 0 ) {
739 DBGC ( ctx, "WPA %p: failed to decrypt GTK: %s\n",
740 ctx, strerror ( rc ) );
741 return rc; /* non-fatal */
742 }
743 if ( pkt->datalen > sizeof ( ctx->gtk.tk ) ) {
744 DBGC ( ctx, "WPA %p: too much GTK data (%d > %zd)\n",
745 ctx, pkt->datalen, sizeof ( ctx->gtk.tk ) );
746 return wpa_fail ( ctx, -EINVAL );
747 }
748
749 memcpy ( &ctx->gtk.tk, pkt->data, pkt->datalen );
750 wpa_install_gtk ( ctx, pkt->datalen, pkt->rsc );
751 }
752
753 DBGC ( ctx, "WPA %p: received 1/2, looks OK\n", ctx );
754
755 return wpa_send_final ( ctx, pkt, is_rsn, kie );
756 }
757
758
759 /**
760 * Handle receipt of EAPOL-Key frame for WPA
761 *
762 * @v iob I/O buffer
763 * @v netdev Network device
764 * @v ll_dest Link-layer destination address
765 * @v ll_source Source link-layer address
766 */
eapol_key_rx(struct io_buffer * iob,struct net_device * netdev,const void * ll_dest __unused,const void * ll_source)767 static int eapol_key_rx ( struct io_buffer *iob, struct net_device *netdev,
768 const void *ll_dest __unused,
769 const void *ll_source )
770 {
771 struct net80211_device *dev = net80211_get ( netdev );
772 struct eapol_key_pkt *pkt = iob->data;
773 int is_rsn, found_ctx;
774 struct wpa_common_ctx *ctx;
775 int rc = 0;
776 struct wpa_kie *kie;
777 u8 their_mic[16], our_mic[16];
778
779 if ( pkt->type != EAPOL_KEY_TYPE_WPA &&
780 pkt->type != EAPOL_KEY_TYPE_RSN ) {
781 DBG ( "EAPOL-Key: packet not of 802.11 type\n" );
782 rc = -EINVAL;
783 goto drop;
784 }
785
786 is_rsn = ( pkt->type == EAPOL_KEY_TYPE_RSN );
787
788 if ( ! dev ) {
789 DBG ( "EAPOL-Key: packet not from 802.11\n" );
790 rc = -EINVAL;
791 goto drop;
792 }
793
794 if ( memcmp ( dev->bssid, ll_source, ETH_ALEN ) != 0 ) {
795 DBG ( "EAPOL-Key: packet not from associated AP\n" );
796 rc = -EINVAL;
797 goto drop;
798 }
799
800 if ( ! ( ntohs ( pkt->info ) & EAPOL_KEY_INFO_KEY_ACK ) ) {
801 DBG ( "EAPOL-Key: packet sent in wrong direction\n" );
802 rc = -EINVAL;
803 goto drop;
804 }
805
806 found_ctx = 0;
807 list_for_each_entry ( ctx, &wpa_contexts, list ) {
808 if ( ctx->dev == dev ) {
809 found_ctx = 1;
810 break;
811 }
812 }
813
814 if ( ! found_ctx ) {
815 DBG ( "EAPOL-Key: no WPA context to handle packet for %p\n",
816 dev );
817 rc = -ENOENT;
818 goto drop;
819 }
820
821 if ( ( void * ) ( pkt + 1 ) + ntohs ( pkt->datalen ) > iob->tail ) {
822 DBGC ( ctx, "WPA %p: packet truncated (has %zd extra bytes, "
823 "states %d)\n", ctx, iob->tail - ( void * ) ( pkt + 1 ),
824 ntohs ( pkt->datalen ) );
825 rc = -EINVAL;
826 goto drop;
827 }
828
829 /* Get a handle on key integrity/encryption handler */
830 kie = wpa_find_kie ( ntohs ( pkt->info ) & EAPOL_KEY_INFO_VERSION );
831 if ( ! kie ) {
832 DBGC ( ctx, "WPA %p: no support for packet version %d\n", ctx,
833 ntohs ( pkt->info ) & EAPOL_KEY_INFO_VERSION );
834 rc = wpa_fail ( ctx, -ENOTSUP );
835 goto drop;
836 }
837
838 /* Check MIC */
839 if ( ntohs ( pkt->info ) & EAPOL_KEY_INFO_KEY_MIC ) {
840 memcpy ( their_mic, pkt->mic, sizeof ( pkt->mic ) );
841 memset ( pkt->mic, 0, sizeof ( pkt->mic ) );
842 kie->mic ( &ctx->ptk.kck, ( void * ) pkt - EAPOL_HDR_LEN,
843 EAPOL_HDR_LEN + sizeof ( *pkt ) +
844 ntohs ( pkt->datalen ), our_mic );
845 DBGC2 ( ctx, "WPA %p MIC comparison (theirs, ours):\n", ctx );
846 DBGC2_HD ( ctx, their_mic, 16 );
847 DBGC2_HD ( ctx, our_mic, 16 );
848 if ( memcmp ( their_mic, our_mic, sizeof ( pkt->mic ) ) != 0 ) {
849 DBGC ( ctx, "WPA %p: EAPOL MIC failure\n", ctx );
850 goto drop;
851 }
852 }
853
854 /* Fix byte order to local */
855 pkt->info = ntohs ( pkt->info );
856 pkt->keysize = ntohs ( pkt->keysize );
857 pkt->datalen = ntohs ( pkt->datalen );
858 pkt->replay = be64_to_cpu ( pkt->replay );
859
860 /* Check replay counter */
861 if ( ctx->replay != ~0ULL && ctx->replay >= pkt->replay ) {
862 DBGC ( ctx, "WPA %p ALERT: Replay detected! "
863 "(%08x:%08x >= %08x:%08x)\n", ctx,
864 ( u32 ) ( ctx->replay >> 32 ), ( u32 ) ctx->replay,
865 ( u32 ) ( pkt->replay >> 32 ), ( u32 ) pkt->replay );
866 rc = 0; /* ignore without error */
867 goto drop;
868 }
869 ctx->replay = pkt->replay;
870
871 /* Decrypt key data */
872 if ( pkt->info & EAPOL_KEY_INFO_KEY_ENC ) {
873 rc = kie->decrypt ( &ctx->ptk.kek, pkt->iv, pkt->data,
874 &pkt->datalen );
875 if ( rc < 0 ) {
876 DBGC ( ctx, "WPA %p: failed to decrypt packet: %s\n",
877 ctx, strerror ( rc ) );
878 goto drop;
879 }
880 }
881
882 /* Hand it off to appropriate handler */
883 switch ( pkt->info & ( EAPOL_KEY_INFO_TYPE |
884 EAPOL_KEY_INFO_KEY_MIC ) ) {
885 case EAPOL_KEY_TYPE_PTK:
886 rc = wpa_handle_1_of_4 ( ctx, pkt, is_rsn, kie );
887 break;
888
889 case EAPOL_KEY_TYPE_PTK | EAPOL_KEY_INFO_KEY_MIC:
890 rc = wpa_handle_3_of_4 ( ctx, pkt, is_rsn, kie );
891 break;
892
893 case EAPOL_KEY_TYPE_GTK | EAPOL_KEY_INFO_KEY_MIC:
894 rc = wpa_handle_1_of_2 ( ctx, pkt, is_rsn, kie );
895 break;
896
897 default:
898 DBGC ( ctx, "WPA %p: Invalid combination of key flags %04x\n",
899 ctx, pkt->info );
900 rc = -EINVAL;
901 break;
902 }
903
904 drop:
905 free_iob ( iob );
906 return rc;
907 }
908
909 struct eapol_handler eapol_key_handler __eapol_handler = {
910 .type = EAPOL_TYPE_KEY,
911 .rx = eapol_key_rx,
912 };
913
914 /* WPA always needs EAPOL in order to be useful */
915 REQUIRING_SYMBOL ( eapol_key_handler );
916 REQUIRE_OBJECT ( eapol );
917