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source: rtems-libbsd/freebsd/sys/net80211/ieee80211_crypto_ccmp.c @ a241ea8

55-freebsd-126-freebsd-12

Last change on this file since a241ea8 was a241ea8, checked in by Christian Mauderer <Christian.Mauderer@…>, on 11/14/16 at 12:46:13
Import IEEE 802.11 from FreeBSD.
Property mode set to `100644`
File size: 18.3 KB

Line
1	#include <machine/rtems-bsd-kernel-space.h>
2
3	/*-
4	* Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
5	* All rights reserved.
6	*
7	* Redistribution and use in source and binary forms, with or without
8	* modification, are permitted provided that the following conditions
9	* are met:
10	* 1. Redistributions of source code must retain the above copyright
11	* notice, this list of conditions and the following disclaimer.
12	* 2. Redistributions in binary form must reproduce the above copyright
13	* notice, this list of conditions and the following disclaimer in the
14	* documentation and/or other materials provided with the distribution.
15	*
16	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26	*/
27
28	#include <sys/cdefs.h>
29	__FBSDID("$FreeBSD$");
30
31	/*
32	* IEEE 802.11i AES-CCMP crypto support.
33	*
34	* Part of this module is derived from similar code in the Host
35	* AP driver. The code is used with the consent of the author and
36	* it's license is included below.
37	*/
38	#include <rtems/bsd/local/opt_wlan.h>
39
40	#include <rtems/bsd/sys/param.h>
41	#include <sys/systm.h>
42	#include <sys/mbuf.h>
43	#include <sys/malloc.h>
44	#include <sys/kernel.h>
45	#include <sys/module.h>
46
47	#include <sys/socket.h>
48
49	#include <net/if.h>
50	#include <net/if_media.h>
51	#include <net/ethernet.h>
52
53	#include <net80211/ieee80211_var.h>
54
55	#include <crypto/rijndael/rijndael.h>
56
57	#define AES_BLOCK_LEN 16
58
59	struct ccmp_ctx {
60	struct ieee80211vap cc_vap; / for diagnostics+statistics */
61	struct ieee80211com *cc_ic;
62	rijndael_ctx cc_aes;
63	};
64
65	static void ccmp_attach(struct ieee80211vap , struct ieee80211_key *);
66	static void ccmp_detach(struct ieee80211_key *);
67	static int ccmp_setkey(struct ieee80211_key *);
68	static void ccmp_setiv(struct ieee80211_key , uint8_t );
69	static int ccmp_encap(struct ieee80211_key , struct mbuf );
70	static int ccmp_decap(struct ieee80211_key , struct mbuf , int);
71	static int ccmp_enmic(struct ieee80211_key , struct mbuf , int);
72	static int ccmp_demic(struct ieee80211_key , struct mbuf , int);
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_setiv = ccmp_setiv,
85	.ic_encap = ccmp_encap,
86	.ic_decap = ccmp_decap,
87	.ic_enmic = ccmp_enmic,
88	.ic_demic = ccmp_demic,
89	};
90
91	static int ccmp_encrypt(struct ieee80211_key , struct mbuf , int hdrlen);
92	static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn,
93	struct mbuf *, int hdrlen);
94
95	/* number of references from net80211 layer */
96	static int nrefs = 0;
97
98	static void *
99	ccmp_attach(struct ieee80211vap vap, struct ieee80211_key k)
100	{
101	struct ccmp_ctx *ctx;
102
103	ctx = (struct ccmp_ctx *) IEEE80211_MALLOC(sizeof(struct ccmp_ctx),
104	M_80211_CRYPTO, IEEE80211_M_NOWAIT \| IEEE80211_M_ZERO);
105	if (ctx == NULL) {
106	vap->iv_stats.is_crypto_nomem++;
107	return NULL;
108	}
109	ctx->cc_vap = vap;
110	ctx->cc_ic = vap->iv_ic;
111	nrefs++; /* NB: we assume caller locking */
112	return ctx;
113	}
114
115	static void
116	ccmp_detach(struct ieee80211_key *k)
117	{
118	struct ccmp_ctx *ctx = k->wk_private;
119
120	IEEE80211_FREE(ctx, M_80211_CRYPTO);
121	KASSERT(nrefs > 0, ("imbalanced attach/detach"));
122	nrefs--; /* NB: we assume caller locking */
123	}
124
125	static int
126	ccmp_setkey(struct ieee80211_key *k)
127	{
128	struct ccmp_ctx *ctx = k->wk_private;
129
130	if (k->wk_keylen != (128/NBBY)) {
131	IEEE80211_DPRINTF(ctx->cc_vap, IEEE80211_MSG_CRYPTO,
132	"%s: Invalid key length %u, expecting %u\n",
133	__func__, k->wk_keylen, 128/NBBY);
134	return 0;
135	}
136	if (k->wk_flags & IEEE80211_KEY_SWENCRYPT)
137	rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY);
138	return 1;
139	}
140
141	static void
142	ccmp_setiv(struct ieee80211_key k, uint8_t ivp)
143	{
144	struct ccmp_ctx *ctx = k->wk_private;
145	struct ieee80211vap *vap = ctx->cc_vap;
146	uint8_t keyid;
147
148	keyid = ieee80211_crypto_get_keyid(vap, k) << 6;
149
150	k->wk_keytsc++;
151	ivp[0] = k->wk_keytsc >> 0; /* PN0 */
152	ivp[1] = k->wk_keytsc >> 8; /* PN1 */
153	ivp[2] = 0; /* Reserved */
154	ivp[3] = keyid \| IEEE80211_WEP_EXTIV; /* KeyID \| ExtID */
155	ivp[4] = k->wk_keytsc >> 16; /* PN2 */
156	ivp[5] = k->wk_keytsc >> 24; /* PN3 */
157	ivp[6] = k->wk_keytsc >> 32; /* PN4 */
158	ivp[7] = k->wk_keytsc >> 40; /* PN5 */
159	}
160
161	/*
162	* Add privacy headers appropriate for the specified key.
163	*/
164	static int
165	ccmp_encap(struct ieee80211_key k, struct mbuf m)
166	{
167	const struct ieee80211_frame *wh;
168	struct ccmp_ctx *ctx = k->wk_private;
169	struct ieee80211com *ic = ctx->cc_ic;
170	uint8_t *ivp;
171	int hdrlen;
172	int is_mgmt;
173
174	hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
175	wh = mtod(m, const struct ieee80211_frame *);
176	is_mgmt = IEEE80211_IS_MGMT(wh);
177
178	/*
179	* Check to see if we need to insert IV/MIC.
180	*
181	* Some offload devices don't require the IV to be inserted
182	* as part of the hardware encryption.
183	*/
184	if (is_mgmt && (k->wk_flags & IEEE80211_KEY_NOIVMGT))
185	return 1;
186	if ((! is_mgmt) && (k->wk_flags & IEEE80211_KEY_NOIV))
187	return 1;
188
189	/*
190	* Copy down 802.11 header and add the IV, KeyID, and ExtIV.
191	*/
192	M_PREPEND(m, ccmp.ic_header, M_NOWAIT);
193	if (m == NULL)
194	return 0;
195	ivp = mtod(m, uint8_t *);
196	ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
197	ivp += hdrlen;
198
199	ccmp_setiv(k, ivp);
200
201	/*
202	* Finally, do software encrypt if needed.
203	*/
204	if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) &&
205	!ccmp_encrypt(k, m, hdrlen))
206	return 0;
207
208	return 1;
209	}
210
211	/*
212	* Add MIC to the frame as needed.
213	*/
214	static int
215	ccmp_enmic(struct ieee80211_key k, struct mbuf m, int force)
216	{
217
218	return 1;
219	}
220
221	static __inline uint64_t
222	READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
223	{
224	uint32_t iv32 = (b0 << 0) \| (b1 << 8) \| (b2 << 16) \| (b3 << 24);
225	uint16_t iv16 = (b4 << 0) \| (b5 << 8);
226	return (((uint64_t)iv16) << 32) \| iv32;
227	}
228
229	/*
230	* Validate and strip privacy headers (and trailer) for a
231	* received frame. The specified key should be correct but
232	* is also verified.
233	*/
234	static int
235	ccmp_decap(struct ieee80211_key k, struct mbuf m, int hdrlen)
236	{
237	const struct ieee80211_rx_stats *rxs;
238	struct ccmp_ctx *ctx = k->wk_private;
239	struct ieee80211vap *vap = ctx->cc_vap;
240	struct ieee80211_frame *wh;
241	uint8_t *ivp, tid;
242	uint64_t pn;
243
244	rxs = ieee80211_get_rx_params_ptr(m);
245
246	if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))
247	goto finish;
248
249	/*
250	* Header should have extended IV and sequence number;
251	* verify the former and validate the latter.
252	*/
253	wh = mtod(m, struct ieee80211_frame *);
254	ivp = mtod(m, uint8_t *) + hdrlen;
255	if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
256	/*
257	* No extended IV; discard frame.
258	*/
259	IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
260	"%s", "missing ExtIV for AES-CCM cipher");
261	vap->iv_stats.is_rx_ccmpformat++;
262	return 0;
263	}
264	tid = ieee80211_gettid(wh);
265	pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
266	if (pn <= k->wk_keyrsc[tid] &&
267	(k->wk_flags & IEEE80211_KEY_NOREPLAY) == 0) {
268	/*
269	* Replay violation.
270	*/
271	ieee80211_notify_replay_failure(vap, wh, k, pn, tid);
272	vap->iv_stats.is_rx_ccmpreplay++;
273	return 0;
274	}
275
276	/*
277	* Check if the device handled the decrypt in hardware.
278	* If so we just strip the header; otherwise we need to
279	* handle the decrypt in software. Note that for the
280	* latter we leave the header in place for use in the
281	* decryption work.
282	*/
283	if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) &&
284	!ccmp_decrypt(k, pn, m, hdrlen))
285	return 0;
286
287	finish:
288	/*
289	* Copy up 802.11 header and strip crypto bits.
290	*/
291	if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) {
292	ovbcopy(mtod(m, void ), mtod(m, uint8_t ) + ccmp.ic_header,
293	hdrlen);
294	m_adj(m, ccmp.ic_header);
295	}
296
297	/*
298	* XXX TODO: see if MMIC_STRIP also covers CCMP MIC trailer.
299	*/
300	if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP)))
301	m_adj(m, -ccmp.ic_trailer);
302
303	/*
304	* Ok to update rsc now.
305	*/
306	if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) {
307	k->wk_keyrsc[tid] = pn;
308	}
309
310	return 1;
311	}
312
313	/*
314	* Verify and strip MIC from the frame.
315	*/
316	static int
317	ccmp_demic(struct ieee80211_key k, struct mbuf m, int force)
318	{
319	return 1;
320	}
321
322	static __inline void
323	xor_block(uint8_t b, const uint8_t a, size_t len)
324	{
325	int i;
326	for (i = 0; i < len; i++)
327	b[i] ^= a[i];
328	}
329
330	/*
331	* Host AP crypt: host-based CCMP encryption implementation for Host AP driver
332	*
333	* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
334	*
335	* This program is free software; you can redistribute it and/or modify
336	* it under the terms of the GNU General Public License version 2 as
337	* published by the Free Software Foundation. See README and COPYING for
338	* more details.
339	*
340	* Alternatively, this software may be distributed under the terms of BSD
341	* license.
342	*/
343
344	static void
345	ccmp_init_blocks(rijndael_ctx ctx, struct ieee80211_frame wh,
346	u_int64_t pn, size_t dlen,
347	uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
348	uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
349	{
350	#define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
351
352	/* CCM Initial Block:
353	* Flag (Include authentication header, M=3 (8-octet MIC),
354	* L=1 (2-octet Dlen))
355	* Nonce: 0x00 \| A2 \| PN
356	* Dlen */
357	b0[0] = 0x59;
358	/* NB: b0[1] set below */
359	IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
360	b0[8] = pn >> 40;
361	b0[9] = pn >> 32;
362	b0[10] = pn >> 24;
363	b0[11] = pn >> 16;
364	b0[12] = pn >> 8;
365	b0[13] = pn >> 0;
366	b0[14] = (dlen >> 8) & 0xff;
367	b0[15] = dlen & 0xff;
368
369	/* AAD:
370	* FC with bits 4..6 and 11..13 masked to zero; 14 is always one
371	* A1 \| A2 \| A3
372	* SC with bits 4..15 (seq#) masked to zero
373	* A4 (if present)
374	* QC (if present)
375	*/
376	aad[0] = 0; /* AAD length >> 8 */
377	/* NB: aad[1] set below */
378	aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */
379	aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */
380	/* NB: we know 3 addresses are contiguous */
381	memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
382	aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
383	aad[23] = 0; /* all bits masked */
384	/*
385	* Construct variable-length portion of AAD based
386	* on whether this is a 4-address frame/QOS frame.
387	* We always zero-pad to 32 bytes before running it
388	* through the cipher.
389	*
390	* We also fill in the priority bits of the CCM
391	* initial block as we know whether or not we have
392	* a QOS frame.
393	*/
394	if (IEEE80211_IS_DSTODS(wh)) {
395	IEEE80211_ADDR_COPY(aad + 24,
396	((struct ieee80211_frame_addr4 *)wh)->i_addr4);
397	if (IS_QOS_DATA(wh)) {
398	struct ieee80211_qosframe_addr4 *qwh4 =
399	(struct ieee80211_qosframe_addr4 *) wh;
400	aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
401	aad[31] = 0;
402	b0[1] = aad[30];
403	aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
404	} else {
405	(uint16_t )&aad[30] = 0;
406	b0[1] = 0;
407	aad[1] = 22 + IEEE80211_ADDR_LEN;
408	}
409	} else {
410	if (IS_QOS_DATA(wh)) {
411	struct ieee80211_qosframe *qwh =
412	(struct ieee80211_qosframe*) wh;
413	aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
414	aad[25] = 0;
415	b0[1] = aad[24];
416	aad[1] = 22 + 2;
417	} else {
418	(uint16_t )&aad[24] = 0;
419	b0[1] = 0;
420	aad[1] = 22;
421	}
422	(uint16_t )&aad[26] = 0;
423	(uint32_t )&aad[28] = 0;
424	}
425
426	/* Start with the first block and AAD */
427	rijndael_encrypt(ctx, b0, auth);
428	xor_block(auth, aad, AES_BLOCK_LEN);
429	rijndael_encrypt(ctx, auth, auth);
430	xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
431	rijndael_encrypt(ctx, auth, auth);
432	b0[0] &= 0x07;
433	b0[14] = b0[15] = 0;
434	rijndael_encrypt(ctx, b0, s0);
435	#undef IS_QOS_DATA
436	}
437
438	#define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \
439	/* Authentication */ \
440	xor_block(_b, _pos, _len); \
441	rijndael_encrypt(&ctx->cc_aes, _b, _b); \
442	/* Encryption, with counter */ \
443	_b0[14] = (_i >> 8) & 0xff; \
444	_b0[15] = _i & 0xff; \
445	rijndael_encrypt(&ctx->cc_aes, _b0, _e); \
446	xor_block(_pos, _e, _len); \
447	} while (0)
448
449	static int
450	ccmp_encrypt(struct ieee80211_key key, struct mbuf m0, int hdrlen)
451	{
452	struct ccmp_ctx *ctx = key->wk_private;
453	struct ieee80211_frame *wh;
454	struct mbuf *m = m0;
455	int data_len, i, space;
456	uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN],
457	e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN];
458	uint8_t *pos;
459
460	ctx->cc_vap->iv_stats.is_crypto_ccmp++;
461
462	wh = mtod(m, struct ieee80211_frame *);
463	data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
464	ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
465	data_len, b0, aad, b, s0);
466
467	i = 1;
468	pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
469	/* NB: assumes header is entirely in first mbuf */
470	space = m->m_len - (hdrlen + ccmp.ic_header);
471	for (;;) {
472	if (space > data_len)
473	space = data_len;
474	/*
475	* Do full blocks.
476	*/
477	while (space >= AES_BLOCK_LEN) {
478	CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
479	pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
480	data_len -= AES_BLOCK_LEN;
481	i++;
482	}
483	if (data_len <= 0) /* no more data */
484	break;
485	m = m->m_next;
486	if (m == NULL) { /* last buffer */
487	if (space != 0) {
488	/*
489	* Short last block.
490	*/
491	CCMP_ENCRYPT(i, b, b0, pos, e, space);
492	}
493	break;
494	}
495	if (space != 0) {
496	uint8_t *pos_next;
497	int space_next;
498	int len, dl, sp;
499	struct mbuf *n;
500
501	/*
502	* Block straddles one or more mbufs, gather data
503	* into the block buffer b, apply the cipher, then
504	* scatter the results back into the mbuf chain.
505	* The buffer will automatically get space bytes
506	* of data at offset 0 copied in+out by the
507	* CCMP_ENCRYPT request so we must take care of
508	* the remaining data.
509	*/
510	n = m;
511	dl = data_len;
512	sp = space;
513	for (;;) {
514	pos_next = mtod(n, uint8_t *);
515	len = min(dl, AES_BLOCK_LEN);
516	space_next = len > sp ? len - sp : 0;
517	if (n->m_len >= space_next) {
518	/*
519	* This mbuf has enough data; just grab
520	* what we need and stop.
521	*/
522	xor_block(b+sp, pos_next, space_next);
523	break;
524	}
525	/*
526	* This mbuf's contents are insufficient,
527	* take 'em all and prepare to advance to
528	* the next mbuf.
529	*/
530	xor_block(b+sp, pos_next, n->m_len);
531	sp += n->m_len, dl -= n->m_len;
532	n = n->m_next;
533	if (n == NULL)
534	break;
535	}
536
537	CCMP_ENCRYPT(i, b, b0, pos, e, space);
538
539	/* NB: just like above, but scatter data to mbufs */
540	dl = data_len;
541	sp = space;
542	for (;;) {
543	pos_next = mtod(m, uint8_t *);
544	len = min(dl, AES_BLOCK_LEN);
545	space_next = len > sp ? len - sp : 0;
546	if (m->m_len >= space_next) {
547	xor_block(pos_next, e+sp, space_next);
548	break;
549	}
550	xor_block(pos_next, e+sp, m->m_len);
551	sp += m->m_len, dl -= m->m_len;
552	m = m->m_next;
553	if (m == NULL)
554	goto done;
555	}
556	/*
557	* Do bookkeeping. m now points to the last mbuf
558	* we grabbed data from. We know we consumed a
559	* full block of data as otherwise we'd have hit
560	* the end of the mbuf chain, so deduct from data_len.
561	* Otherwise advance the block number (i) and setup
562	* pos+space to reflect contents of the new mbuf.
563	*/
564	data_len -= AES_BLOCK_LEN;
565	i++;
566	pos = pos_next + space_next;
567	space = m->m_len - space_next;
568	} else {
569	/*
570	* Setup for next buffer.
571	*/
572	pos = mtod(m, uint8_t *);
573	space = m->m_len;
574	}
575	}
576	done:
577	/* tack on MIC */
578	xor_block(b, s0, ccmp.ic_trailer);
579	return m_append(m0, ccmp.ic_trailer, b);
580	}
581	#undef CCMP_ENCRYPT
582
583	#define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
584	/* Decrypt, with counter */ \
585	_b0[14] = (_i >> 8) & 0xff; \
586	_b0[15] = _i & 0xff; \
587	rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
588	xor_block(_pos, _b, _len); \
589	/* Authentication */ \
590	xor_block(_a, _pos, _len); \
591	rijndael_encrypt(&ctx->cc_aes, _a, _a); \
592	} while (0)
593
594	static int
595	ccmp_decrypt(struct ieee80211_key key, u_int64_t pn, struct mbuf m, int hdrlen)
596	{
597	struct ccmp_ctx *ctx = key->wk_private;
598	struct ieee80211vap *vap = ctx->cc_vap;
599	struct ieee80211_frame *wh;
600	uint8_t aad[2 * AES_BLOCK_LEN];
601	uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
602	uint8_t mic[AES_BLOCK_LEN];
603	size_t data_len;
604	int i;
605	uint8_t *pos;
606	u_int space;
607
608	ctx->cc_vap->iv_stats.is_crypto_ccmp++;
609
610	wh = mtod(m, struct ieee80211_frame *);
611	data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
612	ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
613	m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic);
614	xor_block(mic, b, ccmp.ic_trailer);
615
616	i = 1;
617	pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
618	space = m->m_len - (hdrlen + ccmp.ic_header);
619	for (;;) {
620	if (space > data_len)
621	space = data_len;
622	while (space >= AES_BLOCK_LEN) {
623	CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
624	pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
625	data_len -= AES_BLOCK_LEN;
626	i++;
627	}
628	if (data_len <= 0) /* no more data */
629	break;
630	m = m->m_next;
631	if (m == NULL) { /* last buffer */
632	if (space != 0) /* short last block */
633	CCMP_DECRYPT(i, b, b0, pos, a, space);
634	break;
635	}
636	if (space != 0) {
637	uint8_t *pos_next;
638	u_int space_next;
639	u_int len;
640
641	/*
642	* Block straddles buffers, split references. We
643	* do not handle splits that require >2 buffers
644	* since rx'd frames are never badly fragmented
645	* because drivers typically recv in clusters.
646	*/
647	pos_next = mtod(m, uint8_t *);
648	len = min(data_len, AES_BLOCK_LEN);
649	space_next = len > space ? len - space : 0;
650	KASSERT(m->m_len >= space_next,
651	("not enough data in following buffer, "
652	"m_len %u need %u\n", m->m_len, space_next));
653
654	xor_block(b+space, pos_next, space_next);
655	CCMP_DECRYPT(i, b, b0, pos, a, space);
656	xor_block(pos_next, b+space, space_next);
657	data_len -= len;
658	i++;
659
660	pos = pos_next + space_next;
661	space = m->m_len - space_next;
662	} else {
663	/*
664	* Setup for next buffer.
665	*/
666	pos = mtod(m, uint8_t *);
667	space = m->m_len;
668	}
669	}
670	if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
671	IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
672	"%s", "AES-CCM decrypt failed; MIC mismatch");
673	vap->iv_stats.is_rx_ccmpmic++;
674	return 0;
675	}
676	return 1;
677	}
678	#undef CCMP_DECRYPT
679
680	/*
681	* Module glue.
682	*/
683	IEEE80211_CRYPTO_MODULE(ccmp, 1);

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