xref: /freebsd/sys/net80211/ieee80211_crypto_ccmp.c (revision 6af83ee0d2941d18880b6aaa2b4facd1d30c6106)
1 /*-
2  * Copyright (c) 2002-2005 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  * 3. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * Alternatively, this software may be distributed under the terms of the
17  * GNU General Public License ("GPL") version 2 as published by the Free
18  * Software Foundation.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 /*
36  * IEEE 802.11i AES-CCMP crypto support.
37  *
38  * Part of this module is derived from similar code in the Host
39  * AP driver. The code is used with the consent of the author and
40  * it's license is included below.
41  */
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/mbuf.h>
45 #include <sys/malloc.h>
46 #include <sys/kernel.h>
47 #include <sys/module.h>
48 
49 #include <sys/socket.h>
50 
51 #include <net/if.h>
52 #include <net/if_media.h>
53 #include <net/ethernet.h>
54 
55 #include <net80211/ieee80211_var.h>
56 
57 #include <crypto/rijndael/rijndael.h>
58 
59 #define AES_BLOCK_LEN 16
60 
61 struct ccmp_ctx {
62 	struct ieee80211com *cc_ic;	/* for diagnostics */
63 	rijndael_ctx	     cc_aes;
64 };
65 
66 static	void *ccmp_attach(struct ieee80211com *, struct ieee80211_key *);
67 static	void ccmp_detach(struct ieee80211_key *);
68 static	int ccmp_setkey(struct ieee80211_key *);
69 static	int ccmp_encap(struct ieee80211_key *k, struct mbuf *, u_int8_t keyid);
70 static	int ccmp_decap(struct ieee80211_key *, struct mbuf *);
71 static	int ccmp_enmic(struct ieee80211_key *, struct mbuf *);
72 static	int ccmp_demic(struct ieee80211_key *, struct mbuf *);
73 
74 static const struct ieee80211_cipher ccmp = {
75 	.ic_name	= "AES-CCM",
76 	.ic_cipher	= IEEE80211_CIPHER_AES_CCM,
77 	.ic_header	= IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
78 			  IEEE80211_WEP_EXTIVLEN,
79 	.ic_trailer	= IEEE80211_WEP_MICLEN,
80 	.ic_miclen	= 0,
81 	.ic_attach	= ccmp_attach,
82 	.ic_detach	= ccmp_detach,
83 	.ic_setkey	= ccmp_setkey,
84 	.ic_encap	= ccmp_encap,
85 	.ic_decap	= ccmp_decap,
86 	.ic_enmic	= ccmp_enmic,
87 	.ic_demic	= ccmp_demic,
88 };
89 
90 static	int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen);
91 static	int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn,
92 		struct mbuf *, int hdrlen);
93 
94 static void *
95 ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k)
96 {
97 	struct ccmp_ctx *ctx;
98 
99 	MALLOC(ctx, struct ccmp_ctx *, sizeof(struct ccmp_ctx),
100 		M_DEVBUF, M_NOWAIT | M_ZERO);
101 	if (ctx == NULL) {
102 		ic->ic_stats.is_crypto_nomem++;
103 		return NULL;
104 	}
105 	ctx->cc_ic = ic;
106 	return ctx;
107 }
108 
109 static void
110 ccmp_detach(struct ieee80211_key *k)
111 {
112 	struct ccmp_ctx *ctx = k->wk_private;
113 
114 	FREE(ctx, M_DEVBUF);
115 }
116 
117 static int
118 ccmp_setkey(struct ieee80211_key *k)
119 {
120 	struct ccmp_ctx *ctx = k->wk_private;
121 
122 	if (k->wk_keylen != (128/NBBY)) {
123 		IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
124 			"%s: Invalid key length %u, expecting %u\n",
125 			__func__, k->wk_keylen, 128/NBBY);
126 		return 0;
127 	}
128 	if (k->wk_flags & IEEE80211_KEY_SWCRYPT)
129 		rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY);
130 	return 1;
131 }
132 
133 /*
134  * Add privacy headers appropriate for the specified key.
135  */
136 static int
137 ccmp_encap(struct ieee80211_key *k, struct mbuf *m, u_int8_t keyid)
138 {
139 	struct ccmp_ctx *ctx = k->wk_private;
140 	struct ieee80211com *ic = ctx->cc_ic;
141 	u_int8_t *ivp;
142 	int hdrlen;
143 
144 	hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
145 
146 	/*
147 	 * Copy down 802.11 header and add the IV, KeyID, and ExtIV.
148 	 */
149 	M_PREPEND(m, ccmp.ic_header, M_NOWAIT);
150 	if (m == NULL)
151 		return 0;
152 	ivp = mtod(m, u_int8_t *);
153 	ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
154 	ivp += hdrlen;
155 
156 	k->wk_keytsc++;		/* XXX wrap at 48 bits */
157 	ivp[0] = k->wk_keytsc >> 0;		/* PN0 */
158 	ivp[1] = k->wk_keytsc >> 8;		/* PN1 */
159 	ivp[2] = 0;				/* Reserved */
160 	ivp[3] = keyid | IEEE80211_WEP_EXTIV;	/* KeyID | ExtID */
161 	ivp[4] = k->wk_keytsc >> 16;		/* PN2 */
162 	ivp[5] = k->wk_keytsc >> 24;		/* PN3 */
163 	ivp[6] = k->wk_keytsc >> 32;		/* PN4 */
164 	ivp[7] = k->wk_keytsc >> 40;		/* PN5 */
165 
166 	/*
167 	 * Finally, do software encrypt if neeed.
168 	 */
169 	if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) &&
170 	    !ccmp_encrypt(k, m, hdrlen))
171 		return 0;
172 
173 	return 1;
174 }
175 
176 /*
177  * Add MIC to the frame as needed.
178  */
179 static int
180 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m)
181 {
182 
183 	return 1;
184 }
185 
186 static __inline uint64_t
187 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
188 {
189 	uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
190 	uint16_t iv16 = (b4 << 0) | (b5 << 8);
191 	return (((uint64_t)iv16) << 32) | iv32;
192 }
193 
194 /*
195  * Validate and strip privacy headers (and trailer) for a
196  * received frame. The specified key should be correct but
197  * is also verified.
198  */
199 static int
200 ccmp_decap(struct ieee80211_key *k, struct mbuf *m)
201 {
202 	struct ccmp_ctx *ctx = k->wk_private;
203 	struct ieee80211_frame *wh;
204 	uint8_t *ivp;
205 	uint64_t pn;
206 	int hdrlen;
207 
208 	/*
209 	 * Header should have extended IV and sequence number;
210 	 * verify the former and validate the latter.
211 	 */
212 	wh = mtod(m, struct ieee80211_frame *);
213 	hdrlen = ieee80211_hdrsize(wh);
214 	ivp = mtod(m, uint8_t *) + hdrlen;
215 	if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
216 		/*
217 		 * No extended IV; discard frame.
218 		 */
219 		IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
220 			"[%s] Missing ExtIV for AES-CCM cipher\n",
221 			ether_sprintf(wh->i_addr2));
222 		ctx->cc_ic->ic_stats.is_rx_ccmpformat++;
223 		return 0;
224 	}
225 	pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
226 	if (pn <= k->wk_keyrsc) {
227 		/*
228 		 * Replay violation.
229 		 */
230 		ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn);
231 		ctx->cc_ic->ic_stats.is_rx_ccmpreplay++;
232 		return 0;
233 	}
234 
235 	/*
236 	 * Check if the device handled the decrypt in hardware.
237 	 * If so we just strip the header; otherwise we need to
238 	 * handle the decrypt in software.  Note that for the
239 	 * latter we leave the header in place for use in the
240 	 * decryption work.
241 	 */
242 	if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) &&
243 	    !ccmp_decrypt(k, pn, m, hdrlen))
244 		return 0;
245 
246 	/*
247 	 * Copy up 802.11 header and strip crypto bits.
248 	 */
249 	ovbcopy(mtod(m, void *), mtod(m, u_int8_t *) + ccmp.ic_header, hdrlen);
250 	m_adj(m, ccmp.ic_header);
251 	m_adj(m, -ccmp.ic_trailer);
252 
253 	/*
254 	 * Ok to update rsc now.
255 	 */
256 	k->wk_keyrsc = pn;
257 
258 	return 1;
259 }
260 
261 /*
262  * Verify and strip MIC from the frame.
263  */
264 static int
265 ccmp_demic(struct ieee80211_key *k, struct mbuf *m)
266 {
267 	return 1;
268 }
269 
270 static __inline void
271 xor_block(uint8_t *b, const uint8_t *a, size_t len)
272 {
273 	int i;
274 	for (i = 0; i < len; i++)
275 		b[i] ^= a[i];
276 }
277 
278 /*
279  * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
280  *
281  * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
282  *
283  * This program is free software; you can redistribute it and/or modify
284  * it under the terms of the GNU General Public License version 2 as
285  * published by the Free Software Foundation. See README and COPYING for
286  * more details.
287  *
288  * Alternatively, this software may be distributed under the terms of BSD
289  * license.
290  */
291 
292 static void
293 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh,
294 	u_int64_t pn, size_t dlen,
295 	uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
296 	uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
297 {
298 #define	IS_4ADDRESS(wh) \
299 	((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS)
300 #define	IS_QOS_DATA(wh)	IEEE80211_QOS_HAS_SEQ(wh)
301 
302 	/* CCM Initial Block:
303 	 * Flag (Include authentication header, M=3 (8-octet MIC),
304 	 *       L=1 (2-octet Dlen))
305 	 * Nonce: 0x00 | A2 | PN
306 	 * Dlen */
307 	b0[0] = 0x59;
308 	/* NB: b0[1] set below */
309 	IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
310 	b0[8] = pn >> 40;
311 	b0[9] = pn >> 32;
312 	b0[10] = pn >> 24;
313 	b0[11] = pn >> 16;
314 	b0[12] = pn >> 8;
315 	b0[13] = pn >> 0;
316 	b0[14] = (dlen >> 8) & 0xff;
317 	b0[15] = dlen & 0xff;
318 
319 	/* AAD:
320 	 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
321 	 * A1 | A2 | A3
322 	 * SC with bits 4..15 (seq#) masked to zero
323 	 * A4 (if present)
324 	 * QC (if present)
325 	 */
326 	aad[0] = 0;	/* AAD length >> 8 */
327 	/* NB: aad[1] set below */
328 	aad[2] = wh->i_fc[0] & 0x8f;	/* XXX magic #s */
329 	aad[3] = wh->i_fc[1] & 0xc7;	/* XXX magic #s */
330 	/* NB: we know 3 addresses are contiguous */
331 	memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
332 	aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
333 	aad[23] = 0; /* all bits masked */
334 	/*
335 	 * Construct variable-length portion of AAD based
336 	 * on whether this is a 4-address frame/QOS frame.
337 	 * We always zero-pad to 32 bytes before running it
338 	 * through the cipher.
339 	 *
340 	 * We also fill in the priority bits of the CCM
341 	 * initial block as we know whether or not we have
342 	 * a QOS frame.
343 	 */
344 	if (IS_4ADDRESS(wh)) {
345 		IEEE80211_ADDR_COPY(aad + 24,
346 			((struct ieee80211_frame_addr4 *)wh)->i_addr4);
347 		if (IS_QOS_DATA(wh)) {
348 			struct ieee80211_qosframe_addr4 *qwh4 =
349 				(struct ieee80211_qosframe_addr4 *) wh;
350 			aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
351 			aad[31] = 0;
352 			b0[1] = aad[30];
353 			aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
354 		} else {
355 			*(u_int16_t *)&aad[30] = 0;
356 			b0[1] = 0;
357 			aad[1] = 22 + IEEE80211_ADDR_LEN;
358 		}
359 	} else {
360 		if (IS_QOS_DATA(wh)) {
361 			struct ieee80211_qosframe *qwh =
362 				(struct ieee80211_qosframe*) wh;
363 			aad[24] = qwh->i_qos[0] & 0x0f;	/* just priority bits */
364 			aad[25] = 0;
365 			b0[1] = aad[24];
366 			aad[1] = 22 + 2;
367 		} else {
368 			*(u_int16_t *)&aad[24] = 0;
369 			b0[1] = 0;
370 			aad[1] = 22;
371 		}
372 		*(u_int16_t *)&aad[26] = 0;
373 		*(u_int32_t *)&aad[28] = 0;
374 	}
375 
376 	/* Start with the first block and AAD */
377 	rijndael_encrypt(ctx, b0, auth);
378 	xor_block(auth, aad, AES_BLOCK_LEN);
379 	rijndael_encrypt(ctx, auth, auth);
380 	xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
381 	rijndael_encrypt(ctx, auth, auth);
382 	b0[0] &= 0x07;
383 	b0[14] = b0[15] = 0;
384 	rijndael_encrypt(ctx, b0, s0);
385 #undef	IS_QOS_DATA
386 #undef	IS_4ADDRESS
387 }
388 
389 #define	CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do {	\
390 	/* Authentication */				\
391 	xor_block(_b, _pos, _len);			\
392 	rijndael_encrypt(&ctx->cc_aes, _b, _b);		\
393 	/* Encryption, with counter */			\
394 	_b0[14] = (_i >> 8) & 0xff;			\
395 	_b0[15] = _i & 0xff;				\
396 	rijndael_encrypt(&ctx->cc_aes, _b0, _e);	\
397 	xor_block(_pos, _e, _len);			\
398 } while (0)
399 
400 static int
401 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen)
402 {
403 	struct ccmp_ctx *ctx = key->wk_private;
404 	struct ieee80211_frame *wh;
405 	struct mbuf *m = m0;
406 	int data_len, i;
407 	uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN],
408 		e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN];
409 	uint8_t *pos;
410 	u_int space;
411 
412 	ctx->cc_ic->ic_stats.is_crypto_ccmp++;
413 
414 	wh = mtod(m, struct ieee80211_frame *);
415 	data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
416 	ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
417 		data_len, b0, aad, b, s0);
418 
419 	i = 1;
420 	pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
421 	/* NB: assumes header is entirely in first mbuf */
422 	space = m->m_len - (hdrlen + ccmp.ic_header);
423 	for (;;) {
424 		if (space > data_len)
425 			space = data_len;
426 		/*
427 		 * Do full blocks.
428 		 */
429 		while (space >= AES_BLOCK_LEN) {
430 			CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
431 			pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
432 			data_len -= AES_BLOCK_LEN;
433 			i++;
434 		}
435 		if (data_len <= 0)		/* no more data */
436 			break;
437 		m = m->m_next;
438 		if (m == NULL) {		/* last buffer */
439 			if (space != 0) {
440 				/*
441 				 * Short last block.
442 				 */
443 				CCMP_ENCRYPT(i, b, b0, pos, e, space);
444 			}
445 			break;
446 		}
447 		if (space != 0) {
448 			uint8_t *pos_next;
449 			u_int space_next;
450 			u_int len;
451 
452 			/*
453 			 * Block straddles buffers, split references.  We
454 			 * do not handle splits that require >2 buffers.
455 			 */
456 			pos_next = mtod(m, uint8_t *);
457 			len = min(data_len, AES_BLOCK_LEN);
458 			space_next = len > space ? len - space : 0;
459 			KASSERT(m->m_len >= space_next,
460 				("not enough data in following buffer, "
461 				"m_len %u need %u\n", m->m_len, space_next));
462 
463 			xor_block(b+space, pos_next, space_next);
464 			CCMP_ENCRYPT(i, b, b0, pos, e, space);
465 			xor_block(pos_next, e+space, space_next);
466 			data_len -= len;
467 			/* XXX could check for data_len <= 0 */
468 			i++;
469 
470 			pos = pos_next + space_next;
471 			space = m->m_len - space_next;
472 		} else {
473 			/*
474 			 * Setup for next buffer.
475 			 */
476 			pos = mtod(m, uint8_t *);
477 			space = m->m_len;
478 		}
479 	}
480 	/* tack on MIC */
481 	xor_block(b, s0, ccmp.ic_trailer);
482 	return m_append(m0, ccmp.ic_trailer, b);
483 }
484 #undef CCMP_ENCRYPT
485 
486 #define	CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do {	\
487 	/* Decrypt, with counter */			\
488 	_b0[14] = (_i >> 8) & 0xff;			\
489 	_b0[15] = _i & 0xff;				\
490 	rijndael_encrypt(&ctx->cc_aes, _b0, _b);	\
491 	xor_block(_pos, _b, _len);			\
492 	/* Authentication */				\
493 	xor_block(_a, _pos, _len);			\
494 	rijndael_encrypt(&ctx->cc_aes, _a, _a);		\
495 } while (0)
496 
497 static int
498 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen)
499 {
500 	struct ccmp_ctx *ctx = key->wk_private;
501 	struct ieee80211_frame *wh;
502 	uint8_t aad[2 * AES_BLOCK_LEN];
503 	uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
504 	uint8_t mic[AES_BLOCK_LEN];
505 	size_t data_len;
506 	int i;
507 	uint8_t *pos;
508 	u_int space;
509 
510 	ctx->cc_ic->ic_stats.is_crypto_ccmp++;
511 
512 	wh = mtod(m, struct ieee80211_frame *);
513 	data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
514 	ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
515 	m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic);
516 	xor_block(mic, b, ccmp.ic_trailer);
517 
518 	i = 1;
519 	pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
520 	space = m->m_len - (hdrlen + ccmp.ic_header);
521 	for (;;) {
522 		if (space > data_len)
523 			space = data_len;
524 		while (space >= AES_BLOCK_LEN) {
525 			CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
526 			pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
527 			data_len -= AES_BLOCK_LEN;
528 			i++;
529 		}
530 		if (data_len <= 0)		/* no more data */
531 			break;
532 		m = m->m_next;
533 		if (m == NULL) {		/* last buffer */
534 			if (space != 0)		/* short last block */
535 				CCMP_DECRYPT(i, b, b0, pos, a, space);
536 			break;
537 		}
538 		if (space != 0) {
539 			uint8_t *pos_next;
540 			u_int space_next;
541 			u_int len;
542 
543 			/*
544 			 * Block straddles buffers, split references.  We
545 			 * do not handle splits that require >2 buffers.
546 			 */
547 			pos_next = mtod(m, uint8_t *);
548 			len = min(data_len, AES_BLOCK_LEN);
549 			space_next = len > space ? len - space : 0;
550 			KASSERT(m->m_len >= space_next,
551 				("not enough data in following buffer, "
552 				"m_len %u need %u\n", m->m_len, space_next));
553 
554 			xor_block(b+space, pos_next, space_next);
555 			CCMP_DECRYPT(i, b, b0, pos, a, space);
556 			xor_block(pos_next, b+space, space_next);
557 			data_len -= len;
558 			i++;
559 
560 			pos = pos_next + space_next;
561 			space = m->m_len - space_next;
562 		} else {
563 			/*
564 			 * Setup for next buffer.
565 			 */
566 			pos = mtod(m, uint8_t *);
567 			space = m->m_len;
568 		}
569 	}
570 	if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
571 		IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
572 			"[%s] AES-CCM decrypt failed; MIC mismatch\n",
573 			ether_sprintf(wh->i_addr2));
574 		ctx->cc_ic->ic_stats.is_rx_ccmpmic++;
575 		return 0;
576 	}
577 	return 1;
578 }
579 #undef CCMP_DECRYPT
580 
581 /*
582  * Module glue.
583  */
584 static int
585 ccmp_modevent(module_t mod, int type, void *unused)
586 {
587 	switch (type) {
588 	case MOD_LOAD:
589 		ieee80211_crypto_register(&ccmp);
590 		return 0;
591 	case MOD_UNLOAD:
592 		ieee80211_crypto_unregister(&ccmp);
593 		return 0;
594 	}
595 	return EINVAL;
596 }
597 
598 static moduledata_t ccmp_mod = {
599 	"wlan_ccmp",
600 	ccmp_modevent,
601 	0
602 };
603 DECLARE_MODULE(wlan_ccmp, ccmp_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
604 MODULE_VERSION(wlan_ccmp, 1);
605 MODULE_DEPEND(wlan_ccmp, wlan, 1, 1, 1);
606