1 /*-
2 * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD: releng/11.1/sys/net80211/ieee80211_crypto_ccmp.c 288526 2015-10-03 00:50:13Z adrian $");
28
29 /*
30 * IEEE 802.11i AES-CCMP crypto support.
31 *
32 * Part of this module is derived from similar code in the Host
33 * AP driver. The code is used with the consent of the author and
34 * it's license is included below.
35 */
36 #include "opt_wlan.h"
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/mbuf.h>
41 #include <sys/malloc.h>
42 #include <sys/kernel.h>
43 #include <sys/module.h>
44
45 #include <sys/socket.h>
46
47 #include <net/if.h>
48 #include <net/if_media.h>
49 #include <net/ethernet.h>
50
51 #include <net80211/ieee80211_var.h>
52
53 #include <crypto/rijndael/rijndael.h>
54
55 #define AES_BLOCK_LEN 16
56
57 struct ccmp_ctx {
58 struct ieee80211vap *cc_vap; /* for diagnostics+statistics */
59 struct ieee80211com *cc_ic;
60 rijndael_ctx cc_aes;
61 };
62
63 static void *ccmp_attach(struct ieee80211vap *, struct ieee80211_key *);
64 static void ccmp_detach(struct ieee80211_key *);
65 static int ccmp_setkey(struct ieee80211_key *);
66 static void ccmp_setiv(struct ieee80211_key *, uint8_t *);
67 static int ccmp_encap(struct ieee80211_key *, struct mbuf *);
68 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int);
69 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int);
70 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int);
71
72 static const struct ieee80211_cipher ccmp = {
73 .ic_name = "AES-CCM",
74 .ic_cipher = IEEE80211_CIPHER_AES_CCM,
75 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
76 IEEE80211_WEP_EXTIVLEN,
77 .ic_trailer = IEEE80211_WEP_MICLEN,
78 .ic_miclen = 0,
79 .ic_attach = ccmp_attach,
80 .ic_detach = ccmp_detach,
81 .ic_setkey = ccmp_setkey,
82 .ic_setiv = ccmp_setiv,
83 .ic_encap = ccmp_encap,
84 .ic_decap = ccmp_decap,
85 .ic_enmic = ccmp_enmic,
86 .ic_demic = ccmp_demic,
87 };
88
89 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen);
90 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn,
91 struct mbuf *, int hdrlen);
92
93 /* number of references from net80211 layer */
94 static int nrefs = 0;
95
96 static void *
97 ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k)
98 {
99 struct ccmp_ctx *ctx;
100
101 ctx = (struct ccmp_ctx *) IEEE80211_MALLOC(sizeof(struct ccmp_ctx),
102 M_80211_CRYPTO, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
103 if (ctx == NULL) {
104 vap->iv_stats.is_crypto_nomem++;
105 return NULL;
106 }
107 ctx->cc_vap = vap;
108 ctx->cc_ic = vap->iv_ic;
109 nrefs++; /* NB: we assume caller locking */
110 return ctx;
111 }
112
113 static void
114 ccmp_detach(struct ieee80211_key *k)
115 {
116 struct ccmp_ctx *ctx = k->wk_private;
117
118 IEEE80211_FREE(ctx, M_80211_CRYPTO);
119 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
120 nrefs--; /* NB: we assume caller locking */
121 }
122
123 static int
124 ccmp_setkey(struct ieee80211_key *k)
125 {
126 struct ccmp_ctx *ctx = k->wk_private;
127
128 if (k->wk_keylen != (128/NBBY)) {
129 IEEE80211_DPRINTF(ctx->cc_vap, IEEE80211_MSG_CRYPTO,
130 "%s: Invalid key length %u, expecting %u\n",
131 __func__, k->wk_keylen, 128/NBBY);
132 return 0;
133 }
134 if (k->wk_flags & IEEE80211_KEY_SWENCRYPT)
135 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY);
136 return 1;
137 }
138
139 static void
140 ccmp_setiv(struct ieee80211_key *k, uint8_t *ivp)
141 {
142 struct ccmp_ctx *ctx = k->wk_private;
143 struct ieee80211vap *vap = ctx->cc_vap;
144 uint8_t keyid;
145
146 keyid = ieee80211_crypto_get_keyid(vap, k) << 6;
147
148 k->wk_keytsc++;
149 ivp[0] = k->wk_keytsc >> 0; /* PN0 */
150 ivp[1] = k->wk_keytsc >> 8; /* PN1 */
151 ivp[2] = 0; /* Reserved */
152 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */
153 ivp[4] = k->wk_keytsc >> 16; /* PN2 */
154 ivp[5] = k->wk_keytsc >> 24; /* PN3 */
155 ivp[6] = k->wk_keytsc >> 32; /* PN4 */
156 ivp[7] = k->wk_keytsc >> 40; /* PN5 */
157 }
158
159 /*
160 * Add privacy headers appropriate for the specified key.
161 */
162 static int
163 ccmp_encap(struct ieee80211_key *k, struct mbuf *m)
164 {
165 struct ccmp_ctx *ctx = k->wk_private;
166 struct ieee80211com *ic = ctx->cc_ic;
167 uint8_t *ivp;
168 int hdrlen;
169
170 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
171
172 /*
173 * Copy down 802.11 header and add the IV, KeyID, and ExtIV.
174 */
175 M_PREPEND(m, ccmp.ic_header, M_NOWAIT);
176 if (m == NULL)
177 return 0;
178 ivp = mtod(m, uint8_t *);
179 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
180 ivp += hdrlen;
181
182 ccmp_setiv(k, ivp);
183
184 /*
185 * Finally, do software encrypt if needed.
186 */
187 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) &&
188 !ccmp_encrypt(k, m, hdrlen))
189 return 0;
190
191 return 1;
192 }
193
194 /*
195 * Add MIC to the frame as needed.
196 */
197 static int
198 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force)
199 {
200
201 return 1;
202 }
203
204 static __inline uint64_t
205 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
206 {
207 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
208 uint16_t iv16 = (b4 << 0) | (b5 << 8);
209 return (((uint64_t)iv16) << 32) | iv32;
210 }
211
212 /*
213 * Validate and strip privacy headers (and trailer) for a
214 * received frame. The specified key should be correct but
215 * is also verified.
216 */
217 static int
218 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen)
219 {
220 struct ccmp_ctx *ctx = k->wk_private;
221 struct ieee80211vap *vap = ctx->cc_vap;
222 struct ieee80211_frame *wh;
223 uint8_t *ivp, tid;
224 uint64_t pn;
225
226 /*
227 * Header should have extended IV and sequence number;
228 * verify the former and validate the latter.
229 */
230 wh = mtod(m, struct ieee80211_frame *);
231 ivp = mtod(m, uint8_t *) + hdrlen;
232 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
233 /*
234 * No extended IV; discard frame.
235 */
236 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
237 "%s", "missing ExtIV for AES-CCM cipher");
238 vap->iv_stats.is_rx_ccmpformat++;
239 return 0;
240 }
241 tid = ieee80211_gettid(wh);
242 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
243 if (pn <= k->wk_keyrsc[tid] &&
244 (k->wk_flags & IEEE80211_KEY_NOREPLAY) == 0) {
245 /*
246 * Replay violation.
247 */
248 ieee80211_notify_replay_failure(vap, wh, k, pn, tid);
249 vap->iv_stats.is_rx_ccmpreplay++;
250 return 0;
251 }
252
253 /*
254 * Check if the device handled the decrypt in hardware.
255 * If so we just strip the header; otherwise we need to
256 * handle the decrypt in software. Note that for the
257 * latter we leave the header in place for use in the
258 * decryption work.
259 */
260 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) &&
261 !ccmp_decrypt(k, pn, m, hdrlen))
262 return 0;
263
264 /*
265 * Copy up 802.11 header and strip crypto bits.
266 */
267 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, hdrlen);
268 m_adj(m, ccmp.ic_header);
269 m_adj(m, -ccmp.ic_trailer);
270
271 /*
272 * Ok to update rsc now.
273 */
274 k->wk_keyrsc[tid] = pn;
275
276 return 1;
277 }
278
279 /*
280 * Verify and strip MIC from the frame.
281 */
282 static int
283 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force)
284 {
285 return 1;
286 }
287
288 static __inline void
289 xor_block(uint8_t *b, const uint8_t *a, size_t len)
290 {
291 int i;
292 for (i = 0; i < len; i++)
293 b[i] ^= a[i];
294 }
295
296 /*
297 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
298 *
299 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
300 *
301 * This program is free software; you can redistribute it and/or modify
302 * it under the terms of the GNU General Public License version 2 as
303 * published by the Free Software Foundation. See README and COPYING for
304 * more details.
305 *
306 * Alternatively, this software may be distributed under the terms of BSD
307 * license.
308 */
309
310 static void
311 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh,
312 u_int64_t pn, size_t dlen,
313 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
314 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
315 {
316 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
317
318 /* CCM Initial Block:
319 * Flag (Include authentication header, M=3 (8-octet MIC),
320 * L=1 (2-octet Dlen))
321 * Nonce: 0x00 | A2 | PN
322 * Dlen */
323 b0[0] = 0x59;
324 /* NB: b0[1] set below */
325 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
326 b0[8] = pn >> 40;
327 b0[9] = pn >> 32;
328 b0[10] = pn >> 24;
329 b0[11] = pn >> 16;
330 b0[12] = pn >> 8;
331 b0[13] = pn >> 0;
332 b0[14] = (dlen >> 8) & 0xff;
333 b0[15] = dlen & 0xff;
334
335 /* AAD:
336 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
337 * A1 | A2 | A3
338 * SC with bits 4..15 (seq#) masked to zero
339 * A4 (if present)
340 * QC (if present)
341 */
342 aad[0] = 0; /* AAD length >> 8 */
343 /* NB: aad[1] set below */
344 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */
345 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */
346 /* NB: we know 3 addresses are contiguous */
347 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
348 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
349 aad[23] = 0; /* all bits masked */
350 /*
351 * Construct variable-length portion of AAD based
352 * on whether this is a 4-address frame/QOS frame.
353 * We always zero-pad to 32 bytes before running it
354 * through the cipher.
355 *
356 * We also fill in the priority bits of the CCM
357 * initial block as we know whether or not we have
358 * a QOS frame.
359 */
360 if (IEEE80211_IS_DSTODS(wh)) {
361 IEEE80211_ADDR_COPY(aad + 24,
362 ((struct ieee80211_frame_addr4 *)wh)->i_addr4);
363 if (IS_QOS_DATA(wh)) {
364 struct ieee80211_qosframe_addr4 *qwh4 =
365 (struct ieee80211_qosframe_addr4 *) wh;
366 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
367 aad[31] = 0;
368 b0[1] = aad[30];
369 aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
370 } else {
371 *(uint16_t *)&aad[30] = 0;
372 b0[1] = 0;
373 aad[1] = 22 + IEEE80211_ADDR_LEN;
374 }
375 } else {
376 if (IS_QOS_DATA(wh)) {
377 struct ieee80211_qosframe *qwh =
378 (struct ieee80211_qosframe*) wh;
379 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
380 aad[25] = 0;
381 b0[1] = aad[24];
382 aad[1] = 22 + 2;
383 } else {
384 *(uint16_t *)&aad[24] = 0;
385 b0[1] = 0;
386 aad[1] = 22;
387 }
388 *(uint16_t *)&aad[26] = 0;
389 *(uint32_t *)&aad[28] = 0;
390 }
391
392 /* Start with the first block and AAD */
393 rijndael_encrypt(ctx, b0, auth);
394 xor_block(auth, aad, AES_BLOCK_LEN);
395 rijndael_encrypt(ctx, auth, auth);
396 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
397 rijndael_encrypt(ctx, auth, auth);
398 b0[0] &= 0x07;
399 b0[14] = b0[15] = 0;
400 rijndael_encrypt(ctx, b0, s0);
401 #undef IS_QOS_DATA
402 }
403
404 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \
405 /* Authentication */ \
406 xor_block(_b, _pos, _len); \
407 rijndael_encrypt(&ctx->cc_aes, _b, _b); \
408 /* Encryption, with counter */ \
409 _b0[14] = (_i >> 8) & 0xff; \
410 _b0[15] = _i & 0xff; \
411 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \
412 xor_block(_pos, _e, _len); \
413 } while (0)
414
415 static int
416 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen)
417 {
418 struct ccmp_ctx *ctx = key->wk_private;
419 struct ieee80211_frame *wh;
420 struct mbuf *m = m0;
421 int data_len, i, space;
422 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN],
423 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN];
424 uint8_t *pos;
425
426 ctx->cc_vap->iv_stats.is_crypto_ccmp++;
427
428 wh = mtod(m, struct ieee80211_frame *);
429 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
430 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
431 data_len, b0, aad, b, s0);
432
433 i = 1;
434 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
435 /* NB: assumes header is entirely in first mbuf */
436 space = m->m_len - (hdrlen + ccmp.ic_header);
437 for (;;) {
438 if (space > data_len)
439 space = data_len;
440 /*
441 * Do full blocks.
442 */
443 while (space >= AES_BLOCK_LEN) {
444 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
445 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
446 data_len -= AES_BLOCK_LEN;
447 i++;
448 }
449 if (data_len <= 0) /* no more data */
450 break;
451 m = m->m_next;
452 if (m == NULL) { /* last buffer */
453 if (space != 0) {
454 /*
455 * Short last block.
456 */
457 CCMP_ENCRYPT(i, b, b0, pos, e, space);
458 }
459 break;
460 }
461 if (space != 0) {
462 uint8_t *pos_next;
463 int space_next;
464 int len, dl, sp;
465 struct mbuf *n;
466
467 /*
468 * Block straddles one or more mbufs, gather data
469 * into the block buffer b, apply the cipher, then
470 * scatter the results back into the mbuf chain.
471 * The buffer will automatically get space bytes
472 * of data at offset 0 copied in+out by the
473 * CCMP_ENCRYPT request so we must take care of
474 * the remaining data.
475 */
476 n = m;
477 dl = data_len;
478 sp = space;
479 for (;;) {
480 pos_next = mtod(n, uint8_t *);
481 len = min(dl, AES_BLOCK_LEN);
482 space_next = len > sp ? len - sp : 0;
483 if (n->m_len >= space_next) {
484 /*
485 * This mbuf has enough data; just grab
486 * what we need and stop.
487 */
488 xor_block(b+sp, pos_next, space_next);
489 break;
490 }
491 /*
492 * This mbuf's contents are insufficient,
493 * take 'em all and prepare to advance to
494 * the next mbuf.
495 */
496 xor_block(b+sp, pos_next, n->m_len);
497 sp += n->m_len, dl -= n->m_len;
498 n = n->m_next;
499 if (n == NULL)
500 break;
501 }
502
503 CCMP_ENCRYPT(i, b, b0, pos, e, space);
504
505 /* NB: just like above, but scatter data to mbufs */
506 dl = data_len;
507 sp = space;
508 for (;;) {
509 pos_next = mtod(m, uint8_t *);
510 len = min(dl, AES_BLOCK_LEN);
511 space_next = len > sp ? len - sp : 0;
512 if (m->m_len >= space_next) {
513 xor_block(pos_next, e+sp, space_next);
514 break;
515 }
516 xor_block(pos_next, e+sp, m->m_len);
517 sp += m->m_len, dl -= m->m_len;
518 m = m->m_next;
519 if (m == NULL)
520 goto done;
521 }
522 /*
523 * Do bookkeeping. m now points to the last mbuf
524 * we grabbed data from. We know we consumed a
525 * full block of data as otherwise we'd have hit
526 * the end of the mbuf chain, so deduct from data_len.
527 * Otherwise advance the block number (i) and setup
528 * pos+space to reflect contents of the new mbuf.
529 */
530 data_len -= AES_BLOCK_LEN;
531 i++;
532 pos = pos_next + space_next;
533 space = m->m_len - space_next;
534 } else {
535 /*
536 * Setup for next buffer.
537 */
538 pos = mtod(m, uint8_t *);
539 space = m->m_len;
540 }
541 }
542 done:
543 /* tack on MIC */
544 xor_block(b, s0, ccmp.ic_trailer);
545 return m_append(m0, ccmp.ic_trailer, b);
546 }
547 #undef CCMP_ENCRYPT
548
549 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
550 /* Decrypt, with counter */ \
551 _b0[14] = (_i >> 8) & 0xff; \
552 _b0[15] = _i & 0xff; \
553 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
554 xor_block(_pos, _b, _len); \
555 /* Authentication */ \
556 xor_block(_a, _pos, _len); \
557 rijndael_encrypt(&ctx->cc_aes, _a, _a); \
558 } while (0)
559
560 static int
561 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen)
562 {
563 struct ccmp_ctx *ctx = key->wk_private;
564 struct ieee80211vap *vap = ctx->cc_vap;
565 struct ieee80211_frame *wh;
566 uint8_t aad[2 * AES_BLOCK_LEN];
567 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
568 uint8_t mic[AES_BLOCK_LEN];
569 size_t data_len;
570 int i;
571 uint8_t *pos;
572 u_int space;
573
574 ctx->cc_vap->iv_stats.is_crypto_ccmp++;
575
576 wh = mtod(m, struct ieee80211_frame *);
577 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
578 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
579 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic);
580 xor_block(mic, b, ccmp.ic_trailer);
581
582 i = 1;
583 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
584 space = m->m_len - (hdrlen + ccmp.ic_header);
585 for (;;) {
586 if (space > data_len)
587 space = data_len;
588 while (space >= AES_BLOCK_LEN) {
589 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
590 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
591 data_len -= AES_BLOCK_LEN;
592 i++;
593 }
594 if (data_len <= 0) /* no more data */
595 break;
596 m = m->m_next;
597 if (m == NULL) { /* last buffer */
598 if (space != 0) /* short last block */
599 CCMP_DECRYPT(i, b, b0, pos, a, space);
600 break;
601 }
602 if (space != 0) {
603 uint8_t *pos_next;
604 u_int space_next;
605 u_int len;
606
607 /*
608 * Block straddles buffers, split references. We
609 * do not handle splits that require >2 buffers
610 * since rx'd frames are never badly fragmented
611 * because drivers typically recv in clusters.
612 */
613 pos_next = mtod(m, uint8_t *);
614 len = min(data_len, AES_BLOCK_LEN);
615 space_next = len > space ? len - space : 0;
616 KASSERT(m->m_len >= space_next,
617 ("not enough data in following buffer, "
618 "m_len %u need %u\n", m->m_len, space_next));
619
620 xor_block(b+space, pos_next, space_next);
621 CCMP_DECRYPT(i, b, b0, pos, a, space);
622 xor_block(pos_next, b+space, space_next);
623 data_len -= len;
624 i++;
625
626 pos = pos_next + space_next;
627 space = m->m_len - space_next;
628 } else {
629 /*
630 * Setup for next buffer.
631 */
632 pos = mtod(m, uint8_t *);
633 space = m->m_len;
634 }
635 }
636 if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
637 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
638 "%s", "AES-CCM decrypt failed; MIC mismatch");
639 vap->iv_stats.is_rx_ccmpmic++;
640 return 0;
641 }
642 return 1;
643 }
644 #undef CCMP_DECRYPT
645
646 /*
647 * Module glue.
648 */
649 IEEE80211_CRYPTO_MODULE(ccmp, 1);
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