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 1.2 2006/09/05 00:55:48 dillon 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 <opencrypto/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);
75 static const struct ieee80211_cipher ccmp = {
77 .ic_cipher = IEEE80211_CIPHER_AES_CCM,
78 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
79 IEEE80211_WEP_EXTIVLEN,
80 .ic_trailer = IEEE80211_WEP_MICLEN,
82 .ic_attach = ccmp_attach,
83 .ic_detach = ccmp_detach,
84 .ic_setkey = ccmp_setkey,
85 .ic_encap = ccmp_encap,
86 .ic_decap = ccmp_decap,
87 .ic_enmic = ccmp_enmic,
88 .ic_demic = ccmp_demic,
91 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen);
92 static int ccmp_decrypt(struct ieee80211_key *, uint64_t pn,
93 struct mbuf *, int hdrlen);
95 /* number of references from net80211 layer */
99 ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k)
101 struct ccmp_ctx *ctx;
103 ctx = kmalloc(sizeof(struct ccmp_ctx), M_DEVBUF, M_NOWAIT | M_ZERO);
105 ic->ic_stats.is_crypto_nomem++;
109 nrefs++; /* NB: we assume caller locking */
114 ccmp_detach(struct ieee80211_key *k)
116 struct ccmp_ctx *ctx = k->wk_private;
118 kfree(ctx, M_DEVBUF);
119 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
120 nrefs--; /* NB: we assume caller locking */
124 ccmp_setkey(struct ieee80211_key *k)
126 struct ccmp_ctx *ctx = k->wk_private;
128 if (k->wk_keylen != (128/NBBY)) {
129 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
130 "%s: Invalid key length %u, expecting %u\n",
131 __func__, k->wk_keylen, 128/NBBY);
134 if (k->wk_flags & IEEE80211_KEY_SWCRYPT) {
135 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen * NBBY,
142 * Add privacy headers appropriate for the specified key.
145 ccmp_encap(struct ieee80211_key *k, struct mbuf *m, uint8_t keyid)
147 struct ccmp_ctx *ctx = k->wk_private;
148 struct ieee80211com *ic = ctx->cc_ic;
152 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
155 * Copy down 802.11 header and add the IV, KeyID, and ExtIV.
157 M_PREPEND(m, ccmp.ic_header, M_NOWAIT);
160 ivp = mtod(m, uint8_t *);
161 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
164 k->wk_keytsc++; /* XXX wrap at 48 bits */
165 ivp[0] = k->wk_keytsc >> 0; /* PN0 */
166 ivp[1] = k->wk_keytsc >> 8; /* PN1 */
167 ivp[2] = 0; /* Reserved */
168 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */
169 ivp[4] = k->wk_keytsc >> 16; /* PN2 */
170 ivp[5] = k->wk_keytsc >> 24; /* PN3 */
171 ivp[6] = k->wk_keytsc >> 32; /* PN4 */
172 ivp[7] = k->wk_keytsc >> 40; /* PN5 */
175 * Finally, do software encrypt if neeed.
177 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) &&
178 !ccmp_encrypt(k, m, hdrlen))
185 * Add MIC to the frame as needed.
188 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force)
193 static __inline uint64_t
194 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
196 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
197 uint16_t iv16 = (b4 << 0) | (b5 << 8);
198 return (((uint64_t)iv16) << 32) | iv32;
202 * Validate and strip privacy headers (and trailer) for a
203 * received frame. The specified key should be correct but
207 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen)
209 struct ccmp_ctx *ctx = k->wk_private;
210 struct ieee80211_frame *wh;
215 * Header should have extended IV and sequence number;
216 * verify the former and validate the latter.
218 wh = mtod(m, struct ieee80211_frame *);
219 ivp = mtod(m, uint8_t *) + hdrlen;
220 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
222 * No extended IV; discard frame.
224 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
225 "[%6D] Missing ExtIV for AES-CCM cipher\n",
227 ctx->cc_ic->ic_stats.is_rx_ccmpformat++;
230 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
231 if (pn <= k->wk_keyrsc) {
235 ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn);
236 ctx->cc_ic->ic_stats.is_rx_ccmpreplay++;
241 * Check if the device handled the decrypt in hardware.
242 * If so we just strip the header; otherwise we need to
243 * handle the decrypt in software. Note that for the
244 * latter we leave the header in place for use in the
247 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) &&
248 !ccmp_decrypt(k, pn, m, hdrlen))
252 * Copy up 802.11 header and strip crypto bits.
254 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, hdrlen);
255 m_adj(m, ccmp.ic_header);
256 m_adj(m, -ccmp.ic_trailer);
259 * Ok to update rsc now.
267 * Verify and strip MIC from the frame.
270 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force)
276 xor_block(uint8_t *b, const uint8_t *a, size_t len)
279 for (i = 0; i < len; i++)
284 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
286 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
288 * This program is free software; you can redistribute it and/or modify
289 * it under the terms of the GNU General Public License version 2 as
290 * published by the Free Software Foundation. See README and COPYING for
293 * Alternatively, this software may be distributed under the terms of BSD
298 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh,
299 uint64_t pn, size_t dlen,
300 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
301 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
303 #define IS_4ADDRESS(wh) \
304 ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS)
305 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
307 /* CCM Initial Block:
308 * Flag (Include authentication header, M=3 (8-octet MIC),
309 * L=1 (2-octet Dlen))
310 * Nonce: 0x00 | A2 | PN
313 /* NB: b0[1] set below */
314 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
321 b0[14] = (dlen >> 8) & 0xff;
322 b0[15] = dlen & 0xff;
325 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
327 * SC with bits 4..15 (seq#) masked to zero
331 aad[0] = 0; /* AAD length >> 8 */
332 /* NB: aad[1] set below */
333 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */
334 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */
335 /* NB: we know 3 addresses are contiguous */
336 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
337 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
338 aad[23] = 0; /* all bits masked */
340 * Construct variable-length portion of AAD based
341 * on whether this is a 4-address frame/QOS frame.
342 * We always zero-pad to 32 bytes before running it
343 * through the cipher.
345 * We also fill in the priority bits of the CCM
346 * initial block as we know whether or not we have
349 if (IS_4ADDRESS(wh)) {
350 IEEE80211_ADDR_COPY(aad + 24,
351 ((struct ieee80211_frame_addr4 *)wh)->i_addr4);
352 if (IS_QOS_DATA(wh)) {
353 struct ieee80211_qosframe_addr4 *qwh4 =
354 (struct ieee80211_qosframe_addr4 *) wh;
355 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
358 aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
360 *(uint16_t *)&aad[30] = 0;
362 aad[1] = 22 + IEEE80211_ADDR_LEN;
365 if (IS_QOS_DATA(wh)) {
366 struct ieee80211_qosframe *qwh =
367 (struct ieee80211_qosframe*) wh;
368 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
373 *(uint16_t *)&aad[24] = 0;
377 *(uint16_t *)&aad[26] = 0;
378 *(uint32_t *)&aad[28] = 0;
381 /* Start with the first block and AAD */
382 rijndael_encrypt(ctx, b0, auth);
383 xor_block(auth, aad, AES_BLOCK_LEN);
384 rijndael_encrypt(ctx, auth, auth);
385 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
386 rijndael_encrypt(ctx, auth, auth);
389 rijndael_encrypt(ctx, b0, s0);
394 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \
395 /* Authentication */ \
396 xor_block(_b, _pos, _len); \
397 rijndael_encrypt(&ctx->cc_aes, _b, _b); \
398 /* Encryption, with counter */ \
399 _b0[14] = (_i >> 8) & 0xff; \
400 _b0[15] = _i & 0xff; \
401 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \
402 xor_block(_pos, _e, _len); \
406 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen)
408 struct ccmp_ctx *ctx = key->wk_private;
409 struct ieee80211_frame *wh;
411 int data_len, i, space;
412 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN],
413 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN];
416 ctx->cc_ic->ic_stats.is_crypto_ccmp++;
418 wh = mtod(m, struct ieee80211_frame *);
419 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
420 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
421 data_len, b0, aad, b, s0);
424 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
425 /* NB: assumes header is entirely in first mbuf */
426 space = m->m_len - (hdrlen + ccmp.ic_header);
428 if (space > data_len)
433 while (space >= AES_BLOCK_LEN) {
434 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
435 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
436 data_len -= AES_BLOCK_LEN;
439 if (data_len <= 0) /* no more data */
442 if (m == NULL) { /* last buffer */
447 CCMP_ENCRYPT(i, b, b0, pos, e, space);
458 * Block straddles one or more mbufs, gather data
459 * into the block buffer b, apply the cipher, then
460 * scatter the results back into the mbuf chain.
461 * The buffer will automatically get space bytes
462 * of data at offset 0 copied in+out by the
463 * CCMP_ENCRYPT request so we must take care of
464 * the remaining data.
470 pos_next = mtod(n, uint8_t *);
471 len = min(dl, AES_BLOCK_LEN);
472 space_next = len > sp ? len - sp : 0;
473 if (n->m_len >= space_next) {
475 * This mbuf has enough data; just grab
476 * what we need and stop.
478 xor_block(b+sp, pos_next, space_next);
482 * This mbuf's contents are insufficient,
483 * take 'em all and prepare to advance to
486 xor_block(b+sp, pos_next, n->m_len);
487 sp += n->m_len, dl -= n->m_len;
493 CCMP_ENCRYPT(i, b, b0, pos, e, space);
495 /* NB: just like above, but scatter data to mbufs */
499 pos_next = mtod(m, uint8_t *);
500 len = min(dl, AES_BLOCK_LEN);
501 space_next = len > sp ? len - sp : 0;
502 if (m->m_len >= space_next) {
503 xor_block(pos_next, e+sp, space_next);
506 xor_block(pos_next, e+sp, m->m_len);
507 sp += m->m_len, dl -= m->m_len;
513 * Do bookkeeping. m now points to the last mbuf
514 * we grabbed data from. We know we consumed a
515 * full block of data as otherwise we'd have hit
516 * the end of the mbuf chain, so deduct from data_len.
517 * Otherwise advance the block number (i) and setup
518 * pos+space to reflect contents of the new mbuf.
520 data_len -= AES_BLOCK_LEN;
522 pos = pos_next + space_next;
523 space = m->m_len - space_next;
526 * Setup for next buffer.
528 pos = mtod(m, uint8_t *);
534 xor_block(b, s0, ccmp.ic_trailer);
535 return ieee80211_mbuf_append(m0, ccmp.ic_trailer, b);
539 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
540 /* Decrypt, with counter */ \
541 _b0[14] = (_i >> 8) & 0xff; \
542 _b0[15] = _i & 0xff; \
543 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
544 xor_block(_pos, _b, _len); \
545 /* Authentication */ \
546 xor_block(_a, _pos, _len); \
547 rijndael_encrypt(&ctx->cc_aes, _a, _a); \
551 ccmp_decrypt(struct ieee80211_key *key, uint64_t pn, struct mbuf *m, int hdrlen)
553 struct ccmp_ctx *ctx = key->wk_private;
554 struct ieee80211_frame *wh;
555 uint8_t aad[2 * AES_BLOCK_LEN];
556 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
557 uint8_t mic[AES_BLOCK_LEN];
563 ctx->cc_ic->ic_stats.is_crypto_ccmp++;
565 wh = mtod(m, struct ieee80211_frame *);
566 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
567 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
568 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic);
569 xor_block(mic, b, ccmp.ic_trailer);
572 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
573 space = m->m_len - (hdrlen + ccmp.ic_header);
575 if (space > data_len)
577 while (space >= AES_BLOCK_LEN) {
578 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
579 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
580 data_len -= AES_BLOCK_LEN;
583 if (data_len <= 0) /* no more data */
586 if (m == NULL) { /* last buffer */
587 if (space != 0) /* short last block */
588 CCMP_DECRYPT(i, b, b0, pos, a, space);
597 * Block straddles buffers, split references. We
598 * do not handle splits that require >2 buffers
599 * since rx'd frames are never badly fragmented
600 * because drivers typically recv in clusters.
602 pos_next = mtod(m, uint8_t *);
603 len = min(data_len, AES_BLOCK_LEN);
604 space_next = len > space ? len - space : 0;
605 KASSERT(m->m_len >= space_next,
606 ("not enough data in following buffer, "
607 "m_len %u need %u\n", m->m_len, space_next));
609 xor_block(b+space, pos_next, space_next);
610 CCMP_DECRYPT(i, b, b0, pos, a, space);
611 xor_block(pos_next, b+space, space_next);
615 pos = pos_next + space_next;
616 space = m->m_len - space_next;
619 * Setup for next buffer.
621 pos = mtod(m, uint8_t *);
625 if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
626 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO,
627 "[%6D] AES-CCM decrypt failed; MIC mismatch\n",
629 ctx->cc_ic->ic_stats.is_rx_ccmpmic++;
640 ccmp_modevent(module_t mod, int type, void *unused)
644 ieee80211_crypto_register(&ccmp);
648 printf("wlan_ccmp: still in use (%u dynamic refs)\n",
652 ieee80211_crypto_unregister(&ccmp);
658 static moduledata_t ccmp_mod = {
663 DECLARE_MODULE(wlan_ccmp, ccmp_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
664 MODULE_VERSION(wlan_ccmp, 1);
665 MODULE_DEPEND(wlan_ccmp, wlan, 1, 1, 1);