2 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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.
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.
31 * $FreeBSD: src/sys/net80211/ieee80211_crypto_ccmp.c,v 1.7.2.1 2005/12/22 19:02:08 sam Exp $
32 * $DragonFly: src/sys/netproto/802_11/wlan_ccmp/ieee80211_crypto_ccmp.c,v 1.6 2007/09/15 07:19:23 sephe Exp $
36 * IEEE 802.11i AES-CCMP crypto support.
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.
42 #include <sys/param.h>
43 #include <sys/systm.h>
45 #include <sys/malloc.h>
46 #include <sys/kernel.h>
47 #include <sys/module.h>
49 #include <sys/socket.h>
52 #include <net/if_arp.h>
53 #include <net/if_media.h>
54 #include <net/ethernet.h>
56 #include <netproto/802_11/ieee80211_var.h>
58 #include <crypto/rijndael/rijndael.h>
60 #define AES_BLOCK_LEN 16
63 struct ieee80211com *cc_ic; /* for diagnostics */
67 static void *ccmp_attach(struct ieee80211com *, struct ieee80211_key *);
68 static void ccmp_detach(struct ieee80211_key *);
69 static int ccmp_setkey(struct ieee80211_key *);
70 static int ccmp_encap(struct ieee80211_key *k, struct mbuf *, uint8_t keyid);
71 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int);
72 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int);
73 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int);
74 static int ccmp_getiv(struct ieee80211_key *, struct ieee80211_crypto_iv *,
76 static int ccmp_update(struct ieee80211_key *,
77 const struct ieee80211_crypto_iv *,
78 const struct ieee80211_frame *);
80 static const struct ieee80211_cipher ccmp = {
82 .ic_cipher = IEEE80211_CIPHER_AES_CCM,
83 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
84 IEEE80211_WEP_EXTIVLEN,
85 .ic_trailer = IEEE80211_WEP_MICLEN,
87 .ic_attach = ccmp_attach,
88 .ic_detach = ccmp_detach,
89 .ic_setkey = ccmp_setkey,
90 .ic_encap = ccmp_encap,
91 .ic_decap = ccmp_decap,
92 .ic_enmic = ccmp_enmic,
93 .ic_demic = ccmp_demic,
94 .ic_getiv = ccmp_getiv,
95 .ic_update = ccmp_update
98 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen);
99 static int ccmp_decrypt(struct ieee80211_key *, uint64_t pn,
100 struct mbuf *, int hdrlen);
102 /* number of references from net80211 layer */
103 static int nrefs = 0;
106 ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k)
108 struct ccmp_ctx *ctx;
110 ctx = kmalloc(sizeof(struct ccmp_ctx), M_DEVBUF, M_NOWAIT | M_ZERO);
112 ic->ic_stats.is_crypto_nomem++;
116 nrefs++; /* NB: we assume caller locking */
121 ccmp_detach(struct ieee80211_key *k)
123 struct ccmp_ctx *ctx = k->wk_private;
125 kfree(ctx, M_DEVBUF);
126 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
127 nrefs--; /* NB: we assume caller locking */
131 ccmp_setkey(struct ieee80211_key *k)
133 struct ccmp_ctx *ctx = k->wk_private;
135 if (k->wk_keylen != (128/NBBY)) {
136 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
137 "%s: Invalid key length %u, expecting %u\n",
138 __func__, k->wk_keylen, 128/NBBY);
141 if (k->wk_flags & IEEE80211_KEY_SWCRYPT)
142 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen * NBBY);
147 * Add privacy headers appropriate for the specified key.
150 ccmp_encap(struct ieee80211_key *k, struct mbuf *m, uint8_t keyid)
152 struct ccmp_ctx *ctx = k->wk_private;
153 struct ieee80211com *ic = ctx->cc_ic;
157 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
160 * Copy down 802.11 header and add the IV, KeyID, and ExtIV.
162 M_PREPEND(m, ccmp.ic_header, MB_DONTWAIT);
165 ivp = mtod(m, uint8_t *);
166 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
169 k->wk_keytsc++; /* XXX wrap at 48 bits */
170 ivp[0] = k->wk_keytsc >> 0; /* PN0 */
171 ivp[1] = k->wk_keytsc >> 8; /* PN1 */
172 ivp[2] = 0; /* Reserved */
173 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */
174 ivp[4] = k->wk_keytsc >> 16; /* PN2 */
175 ivp[5] = k->wk_keytsc >> 24; /* PN3 */
176 ivp[6] = k->wk_keytsc >> 32; /* PN4 */
177 ivp[7] = k->wk_keytsc >> 40; /* PN5 */
180 * Finally, do software encrypt if neeed.
182 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) &&
183 !ccmp_encrypt(k, m, hdrlen))
190 ccmp_getiv(struct ieee80211_key *k, struct ieee80211_crypto_iv *iv,
193 uint8_t *ivp = (uint8_t *)iv;
195 k->wk_keytsc++; /* XXX wrap at 48 bits */
196 ivp[0] = k->wk_keytsc >> 0; /* PN0 */
197 ivp[1] = k->wk_keytsc >> 8; /* PN1 */
198 ivp[2] = 0; /* Reserved */
199 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */
200 ivp[4] = k->wk_keytsc >> 16; /* PN2 */
201 ivp[5] = k->wk_keytsc >> 24; /* PN3 */
202 ivp[6] = k->wk_keytsc >> 32; /* PN4 */
203 ivp[7] = k->wk_keytsc >> 40; /* PN5 */
209 * Add MIC to the frame as needed.
212 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force)
217 static __inline uint64_t
218 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
220 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
221 uint16_t iv16 = (b4 << 0) | (b5 << 8);
222 return (((uint64_t)iv16) << 32) | iv32;
226 * Validate and strip privacy headers (and trailer) for a
227 * received frame. The specified key should be correct but
231 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen)
233 struct ccmp_ctx *ctx = k->wk_private;
234 struct ieee80211_frame *wh;
239 * Header should have extended IV and sequence number;
240 * verify the former and validate the latter.
242 wh = mtod(m, struct ieee80211_frame *);
243 ivp = mtod(m, uint8_t *) + hdrlen;
244 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
246 * No extended IV; discard frame.
248 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
249 "[%6D] Missing ExtIV for AES-CCM cipher\n",
251 ctx->cc_ic->ic_stats.is_rx_ccmpformat++;
254 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
255 if (pn <= k->wk_keyrsc) {
259 ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn);
260 ctx->cc_ic->ic_stats.is_rx_ccmpreplay++;
265 * Check if the device handled the decrypt in hardware.
266 * If so we just strip the header; otherwise we need to
267 * handle the decrypt in software. Note that for the
268 * latter we leave the header in place for use in the
271 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) &&
272 !ccmp_decrypt(k, pn, m, hdrlen))
276 * Copy up 802.11 header and strip crypto bits.
278 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, hdrlen);
279 m_adj(m, ccmp.ic_header);
280 m_adj(m, -ccmp.ic_trailer);
283 * Ok to update rsc now.
291 ccmp_update(struct ieee80211_key *k, const struct ieee80211_crypto_iv *iv,
292 const struct ieee80211_frame *wh)
294 struct ccmp_ctx *ctx = k->wk_private;
295 const uint8_t *ivp = (const uint8_t *)iv;
299 * Header should have extended IV and sequence number;
300 * verify the former and validate the latter.
302 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
304 * No extended IV; discard frame.
306 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
307 "[%6D] Missing ExtIV for AES-CCM cipher\n",
309 ctx->cc_ic->ic_stats.is_rx_ccmpformat++;
312 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
313 if (pn <= k->wk_keyrsc) {
317 ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn);
318 ctx->cc_ic->ic_stats.is_rx_ccmpreplay++;
323 * Ok to update rsc now.
330 * Verify and strip MIC from the frame.
333 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force)
339 xor_block(uint8_t *b, const uint8_t *a, size_t len)
342 for (i = 0; i < len; i++)
347 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
349 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
351 * This program is free software; you can redistribute it and/or modify
352 * it under the terms of the GNU General Public License version 2 as
353 * published by the Free Software Foundation. See README and COPYING for
356 * Alternatively, this software may be distributed under the terms of BSD
361 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh,
362 uint64_t pn, size_t dlen,
363 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
364 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
366 #define IS_4ADDRESS(wh) \
367 ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS)
368 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
370 /* CCM Initial Block:
371 * Flag (Include authentication header, M=3 (8-octet MIC),
372 * L=1 (2-octet Dlen))
373 * Nonce: 0x00 | A2 | PN
376 /* NB: b0[1] set below */
377 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
384 b0[14] = (dlen >> 8) & 0xff;
385 b0[15] = dlen & 0xff;
388 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
390 * SC with bits 4..15 (seq#) masked to zero
394 aad[0] = 0; /* AAD length >> 8 */
395 /* NB: aad[1] set below */
396 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */
397 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */
398 /* NB: we know 3 addresses are contiguous */
399 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
400 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
401 aad[23] = 0; /* all bits masked */
403 * Construct variable-length portion of AAD based
404 * on whether this is a 4-address frame/QOS frame.
405 * We always zero-pad to 32 bytes before running it
406 * through the cipher.
408 * We also fill in the priority bits of the CCM
409 * initial block as we know whether or not we have
412 if (IS_4ADDRESS(wh)) {
413 IEEE80211_ADDR_COPY(aad + 24,
414 ((struct ieee80211_frame_addr4 *)wh)->i_addr4);
415 if (IS_QOS_DATA(wh)) {
416 struct ieee80211_qosframe_addr4 *qwh4 =
417 (struct ieee80211_qosframe_addr4 *) wh;
418 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
421 aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
423 *(uint16_t *)&aad[30] = 0;
425 aad[1] = 22 + IEEE80211_ADDR_LEN;
428 if (IS_QOS_DATA(wh)) {
429 struct ieee80211_qosframe *qwh =
430 (struct ieee80211_qosframe*) wh;
431 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
436 *(uint16_t *)&aad[24] = 0;
440 *(uint16_t *)&aad[26] = 0;
441 *(uint32_t *)&aad[28] = 0;
444 /* Start with the first block and AAD */
445 rijndael_encrypt(ctx, b0, auth);
446 xor_block(auth, aad, AES_BLOCK_LEN);
447 rijndael_encrypt(ctx, auth, auth);
448 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
449 rijndael_encrypt(ctx, auth, auth);
452 rijndael_encrypt(ctx, b0, s0);
457 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \
458 /* Authentication */ \
459 xor_block(_b, _pos, _len); \
460 rijndael_encrypt(&ctx->cc_aes, _b, _b); \
461 /* Encryption, with counter */ \
462 _b0[14] = (_i >> 8) & 0xff; \
463 _b0[15] = _i & 0xff; \
464 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \
465 xor_block(_pos, _e, _len); \
469 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen)
471 struct ccmp_ctx *ctx = key->wk_private;
472 struct ieee80211_frame *wh;
474 int data_len, i, space;
475 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN],
476 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN];
479 ctx->cc_ic->ic_stats.is_crypto_ccmp++;
481 wh = mtod(m, struct ieee80211_frame *);
482 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
483 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
484 data_len, b0, aad, b, s0);
487 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
488 /* NB: assumes header is entirely in first mbuf */
489 space = m->m_len - (hdrlen + ccmp.ic_header);
491 if (space > data_len)
496 while (space >= AES_BLOCK_LEN) {
497 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
498 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
499 data_len -= AES_BLOCK_LEN;
502 if (data_len <= 0) /* no more data */
505 if (m == NULL) { /* last buffer */
510 CCMP_ENCRYPT(i, b, b0, pos, e, space);
521 * Block straddles one or more mbufs, gather data
522 * into the block buffer b, apply the cipher, then
523 * scatter the results back into the mbuf chain.
524 * The buffer will automatically get space bytes
525 * of data at offset 0 copied in+out by the
526 * CCMP_ENCRYPT request so we must take care of
527 * the remaining data.
533 pos_next = mtod(n, uint8_t *);
534 len = min(dl, AES_BLOCK_LEN);
535 space_next = len > sp ? len - sp : 0;
536 if (n->m_len >= space_next) {
538 * This mbuf has enough data; just grab
539 * what we need and stop.
541 xor_block(b+sp, pos_next, space_next);
545 * This mbuf's contents are insufficient,
546 * take 'em all and prepare to advance to
549 xor_block(b+sp, pos_next, n->m_len);
550 sp += n->m_len, dl -= n->m_len;
556 CCMP_ENCRYPT(i, b, b0, pos, e, space);
558 /* NB: just like above, but scatter data to mbufs */
562 pos_next = mtod(m, uint8_t *);
563 len = min(dl, AES_BLOCK_LEN);
564 space_next = len > sp ? len - sp : 0;
565 if (m->m_len >= space_next) {
566 xor_block(pos_next, e+sp, space_next);
569 xor_block(pos_next, e+sp, m->m_len);
570 sp += m->m_len, dl -= m->m_len;
576 * Do bookkeeping. m now points to the last mbuf
577 * we grabbed data from. We know we consumed a
578 * full block of data as otherwise we'd have hit
579 * the end of the mbuf chain, so deduct from data_len.
580 * Otherwise advance the block number (i) and setup
581 * pos+space to reflect contents of the new mbuf.
583 data_len -= AES_BLOCK_LEN;
585 pos = pos_next + space_next;
586 space = m->m_len - space_next;
589 * Setup for next buffer.
591 pos = mtod(m, uint8_t *);
597 xor_block(b, s0, ccmp.ic_trailer);
598 return ieee80211_mbuf_append(m0, ccmp.ic_trailer, b);
602 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
603 /* Decrypt, with counter */ \
604 _b0[14] = (_i >> 8) & 0xff; \
605 _b0[15] = _i & 0xff; \
606 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
607 xor_block(_pos, _b, _len); \
608 /* Authentication */ \
609 xor_block(_a, _pos, _len); \
610 rijndael_encrypt(&ctx->cc_aes, _a, _a); \
614 ccmp_decrypt(struct ieee80211_key *key, uint64_t pn, struct mbuf *m, int hdrlen)
616 struct ccmp_ctx *ctx = key->wk_private;
617 struct ieee80211_frame *wh;
618 uint8_t aad[2 * AES_BLOCK_LEN];
619 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
620 uint8_t mic[AES_BLOCK_LEN];
626 ctx->cc_ic->ic_stats.is_crypto_ccmp++;
628 wh = mtod(m, struct ieee80211_frame *);
629 data_len = m->m_pkthdr.len -
630 (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
631 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
632 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer,
634 xor_block(mic, b, ccmp.ic_trailer);
637 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
638 space = m->m_len - (hdrlen + ccmp.ic_header);
640 if (space > data_len)
642 while (space >= AES_BLOCK_LEN) {
643 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
644 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
645 data_len -= AES_BLOCK_LEN;
648 if (data_len <= 0) /* no more data */
651 if (m == NULL) { /* last buffer */
652 if (space != 0) /* short last block */
653 CCMP_DECRYPT(i, b, b0, pos, a, space);
662 * Block straddles buffers, split references. We
663 * do not handle splits that require >2 buffers
664 * since rx'd frames are never badly fragmented
665 * because drivers typically recv in clusters.
667 pos_next = mtod(m, uint8_t *);
668 len = min(data_len, AES_BLOCK_LEN);
669 space_next = len > space ? len - space : 0;
670 KASSERT(m->m_len >= space_next,
671 ("not enough data in following buffer, "
672 "m_len %u need %u\n", m->m_len, space_next));
674 xor_block(b+space, pos_next, space_next);
675 CCMP_DECRYPT(i, b, b0, pos, a, space);
676 xor_block(pos_next, b+space, space_next);
680 pos = pos_next + space_next;
681 space = m->m_len - space_next;
684 * Setup for next buffer.
686 pos = mtod(m, uint8_t *);
690 if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
691 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
692 "[%6D] AES-CCM decrypt failed; MIC mismatch\n",
694 ctx->cc_ic->ic_stats.is_rx_ccmpmic++;
705 ccmp_modevent(module_t mod, int type, void *unused)
709 ieee80211_crypto_register(&ccmp);
713 kprintf("wlan_ccmp: still in use (%u dynamic refs)\n",
717 ieee80211_crypto_unregister(&ccmp);
723 static moduledata_t ccmp_mod = {
728 DECLARE_MODULE(wlan_ccmp, ccmp_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
729 MODULE_VERSION(wlan_ccmp, 1);
730 MODULE_DEPEND(wlan_ccmp, wlan, 1, 1, 1);