2 * Copyright (c) 2002-2008 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.
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.
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
30 * IEEE 802.11i AES-CCMP crypto support.
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.
38 #include <sys/param.h>
39 #include <sys/systm.h>
41 #include <sys/malloc.h>
42 #include <sys/kernel.h>
43 #include <sys/module.h>
45 #include <sys/socket.h>
48 #include <net/if_media.h>
49 #include <net/ethernet.h>
51 #include <net80211/ieee80211_var.h>
53 #include <crypto/rijndael/rijndael.h>
55 #define AES_BLOCK_LEN 16
58 struct ieee80211vap *cc_vap; /* for diagnostics+statistics */
59 struct ieee80211com *cc_ic;
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 int ccmp_encap(struct ieee80211_key *k, struct mbuf *, uint8_t keyid);
67 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int);
68 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int);
69 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int);
71 static const struct ieee80211_cipher ccmp = {
73 .ic_cipher = IEEE80211_CIPHER_AES_CCM,
74 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
75 IEEE80211_WEP_EXTIVLEN,
76 .ic_trailer = IEEE80211_WEP_MICLEN,
78 .ic_attach = ccmp_attach,
79 .ic_detach = ccmp_detach,
80 .ic_setkey = ccmp_setkey,
81 .ic_encap = ccmp_encap,
82 .ic_decap = ccmp_decap,
83 .ic_enmic = ccmp_enmic,
84 .ic_demic = ccmp_demic,
87 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen);
88 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn,
89 struct mbuf *, int hdrlen);
91 /* number of references from net80211 layer */
95 ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k)
99 ctx = (struct ccmp_ctx *) malloc(sizeof(struct ccmp_ctx),
100 M_80211_CRYPTO, M_NOWAIT | M_ZERO);
102 vap->iv_stats.is_crypto_nomem++;
106 ctx->cc_ic = vap->iv_ic;
107 nrefs++; /* NB: we assume caller locking */
112 ccmp_detach(struct ieee80211_key *k)
114 struct ccmp_ctx *ctx = k->wk_private;
116 free(ctx, M_80211_CRYPTO);
117 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
118 nrefs--; /* NB: we assume caller locking */
122 ccmp_setkey(struct ieee80211_key *k)
124 struct ccmp_ctx *ctx = k->wk_private;
126 if (k->wk_keylen != (128/NBBY)) {
127 IEEE80211_DPRINTF(ctx->cc_vap, IEEE80211_MSG_CRYPTO,
128 "%s: Invalid key length %u, expecting %u\n",
129 __func__, k->wk_keylen, 128/NBBY);
132 if (k->wk_flags & IEEE80211_KEY_SWENCRYPT)
133 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY);
138 * Add privacy headers appropriate for the specified key.
141 ccmp_encap(struct ieee80211_key *k, struct mbuf *m, uint8_t keyid)
143 struct ccmp_ctx *ctx = k->wk_private;
144 struct ieee80211com *ic = ctx->cc_ic;
148 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
151 * Copy down 802.11 header and add the IV, KeyID, and ExtIV.
153 M_PREPEND(m, ccmp.ic_header, M_NOWAIT);
156 ivp = mtod(m, uint8_t *);
157 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
160 k->wk_keytsc++; /* XXX wrap at 48 bits */
161 ivp[0] = k->wk_keytsc >> 0; /* PN0 */
162 ivp[1] = k->wk_keytsc >> 8; /* PN1 */
163 ivp[2] = 0; /* Reserved */
164 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */
165 ivp[4] = k->wk_keytsc >> 16; /* PN2 */
166 ivp[5] = k->wk_keytsc >> 24; /* PN3 */
167 ivp[6] = k->wk_keytsc >> 32; /* PN4 */
168 ivp[7] = k->wk_keytsc >> 40; /* PN5 */
171 * Finally, do software encrypt if neeed.
173 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) &&
174 !ccmp_encrypt(k, m, hdrlen))
181 * Add MIC to the frame as needed.
184 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force)
190 static __inline uint64_t
191 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
193 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
194 uint16_t iv16 = (b4 << 0) | (b5 << 8);
195 return (((uint64_t)iv16) << 32) | iv32;
199 * Validate and strip privacy headers (and trailer) for a
200 * received frame. The specified key should be correct but
204 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen)
206 struct ccmp_ctx *ctx = k->wk_private;
207 struct ieee80211vap *vap = ctx->cc_vap;
208 struct ieee80211_frame *wh;
213 * Header should have extended IV and sequence number;
214 * verify the former and validate the latter.
216 wh = mtod(m, struct ieee80211_frame *);
217 ivp = mtod(m, uint8_t *) + hdrlen;
218 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
220 * No extended IV; discard frame.
222 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
223 "%s", "missing ExtIV for AES-CCM cipher");
224 vap->iv_stats.is_rx_ccmpformat++;
227 tid = ieee80211_gettid(wh);
228 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
229 if (pn <= k->wk_keyrsc[tid]) {
233 ieee80211_notify_replay_failure(vap, wh, k, pn, tid);
234 vap->iv_stats.is_rx_ccmpreplay++;
239 * Check if the device handled the decrypt in hardware.
240 * If so we just strip the header; otherwise we need to
241 * handle the decrypt in software. Note that for the
242 * latter we leave the header in place for use in the
245 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) &&
246 !ccmp_decrypt(k, pn, m, hdrlen))
250 * Copy up 802.11 header and strip crypto bits.
252 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, hdrlen);
253 m_adj(m, ccmp.ic_header);
254 m_adj(m, -ccmp.ic_trailer);
257 * Ok to update rsc now.
259 k->wk_keyrsc[tid] = pn;
265 * Verify and strip MIC from the frame.
268 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force)
274 xor_block(uint8_t *b, const uint8_t *a, size_t len)
277 for (i = 0; i < len; i++)
282 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
284 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
286 * This program is free software; you can redistribute it and/or modify
287 * it under the terms of the GNU General Public License version 2 as
288 * published by the Free Software Foundation. See README and COPYING for
291 * Alternatively, this software may be distributed under the terms of BSD
296 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh,
297 u_int64_t pn, size_t dlen,
298 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
299 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
301 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
303 /* CCM Initial Block:
304 * Flag (Include authentication header, M=3 (8-octet MIC),
305 * L=1 (2-octet Dlen))
306 * Nonce: 0x00 | A2 | PN
309 /* NB: b0[1] set below */
310 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
317 b0[14] = (dlen >> 8) & 0xff;
318 b0[15] = dlen & 0xff;
321 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
323 * SC with bits 4..15 (seq#) masked to zero
327 aad[0] = 0; /* AAD length >> 8 */
328 /* NB: aad[1] set below */
329 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */
330 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */
331 /* NB: we know 3 addresses are contiguous */
332 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
333 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
334 aad[23] = 0; /* all bits masked */
336 * Construct variable-length portion of AAD based
337 * on whether this is a 4-address frame/QOS frame.
338 * We always zero-pad to 32 bytes before running it
339 * through the cipher.
341 * We also fill in the priority bits of the CCM
342 * initial block as we know whether or not we have
345 if (IEEE80211_IS_DSTODS(wh)) {
346 IEEE80211_ADDR_COPY(aad + 24,
347 ((struct ieee80211_frame_addr4 *)wh)->i_addr4);
348 if (IS_QOS_DATA(wh)) {
349 struct ieee80211_qosframe_addr4 *qwh4 =
350 (struct ieee80211_qosframe_addr4 *) wh;
351 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
354 aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
356 *(uint16_t *)&aad[30] = 0;
358 aad[1] = 22 + IEEE80211_ADDR_LEN;
361 if (IS_QOS_DATA(wh)) {
362 struct ieee80211_qosframe *qwh =
363 (struct ieee80211_qosframe*) wh;
364 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
369 *(uint16_t *)&aad[24] = 0;
373 *(uint16_t *)&aad[26] = 0;
374 *(uint32_t *)&aad[28] = 0;
377 /* Start with the first block and AAD */
378 rijndael_encrypt(ctx, b0, auth);
379 xor_block(auth, aad, AES_BLOCK_LEN);
380 rijndael_encrypt(ctx, auth, auth);
381 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
382 rijndael_encrypt(ctx, auth, auth);
385 rijndael_encrypt(ctx, b0, s0);
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); \
401 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen)
403 struct ccmp_ctx *ctx = key->wk_private;
404 struct ieee80211_frame *wh;
406 int data_len, i, space;
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];
411 ctx->cc_vap->iv_stats.is_crypto_ccmp++;
413 wh = mtod(m, struct ieee80211_frame *);
414 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
415 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
416 data_len, b0, aad, b, s0);
419 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
420 /* NB: assumes header is entirely in first mbuf */
421 space = m->m_len - (hdrlen + ccmp.ic_header);
423 if (space > data_len)
428 while (space >= AES_BLOCK_LEN) {
429 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
430 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
431 data_len -= AES_BLOCK_LEN;
434 if (data_len <= 0) /* no more data */
437 if (m == NULL) { /* last buffer */
442 CCMP_ENCRYPT(i, b, b0, pos, e, space);
453 * Block straddles one or more mbufs, gather data
454 * into the block buffer b, apply the cipher, then
455 * scatter the results back into the mbuf chain.
456 * The buffer will automatically get space bytes
457 * of data at offset 0 copied in+out by the
458 * CCMP_ENCRYPT request so we must take care of
459 * the remaining data.
465 pos_next = mtod(n, uint8_t *);
466 len = min(dl, AES_BLOCK_LEN);
467 space_next = len > sp ? len - sp : 0;
468 if (n->m_len >= space_next) {
470 * This mbuf has enough data; just grab
471 * what we need and stop.
473 xor_block(b+sp, pos_next, space_next);
477 * This mbuf's contents are insufficient,
478 * take 'em all and prepare to advance to
481 xor_block(b+sp, pos_next, n->m_len);
482 sp += n->m_len, dl -= n->m_len;
488 CCMP_ENCRYPT(i, b, b0, pos, e, space);
490 /* NB: just like above, but scatter data to mbufs */
494 pos_next = mtod(m, uint8_t *);
495 len = min(dl, AES_BLOCK_LEN);
496 space_next = len > sp ? len - sp : 0;
497 if (m->m_len >= space_next) {
498 xor_block(pos_next, e+sp, space_next);
501 xor_block(pos_next, e+sp, m->m_len);
502 sp += m->m_len, dl -= m->m_len;
508 * Do bookkeeping. m now points to the last mbuf
509 * we grabbed data from. We know we consumed a
510 * full block of data as otherwise we'd have hit
511 * the end of the mbuf chain, so deduct from data_len.
512 * Otherwise advance the block number (i) and setup
513 * pos+space to reflect contents of the new mbuf.
515 data_len -= AES_BLOCK_LEN;
517 pos = pos_next + space_next;
518 space = m->m_len - space_next;
521 * Setup for next buffer.
523 pos = mtod(m, uint8_t *);
529 xor_block(b, s0, ccmp.ic_trailer);
530 return m_append(m0, ccmp.ic_trailer, b);
534 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
535 /* Decrypt, with counter */ \
536 _b0[14] = (_i >> 8) & 0xff; \
537 _b0[15] = _i & 0xff; \
538 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
539 xor_block(_pos, _b, _len); \
540 /* Authentication */ \
541 xor_block(_a, _pos, _len); \
542 rijndael_encrypt(&ctx->cc_aes, _a, _a); \
546 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen)
548 struct ccmp_ctx *ctx = key->wk_private;
549 struct ieee80211vap *vap = ctx->cc_vap;
550 struct ieee80211_frame *wh;
551 uint8_t aad[2 * AES_BLOCK_LEN];
552 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
553 uint8_t mic[AES_BLOCK_LEN];
559 ctx->cc_vap->iv_stats.is_crypto_ccmp++;
561 wh = mtod(m, struct ieee80211_frame *);
562 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
563 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
564 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic);
565 xor_block(mic, b, ccmp.ic_trailer);
568 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
569 space = m->m_len - (hdrlen + ccmp.ic_header);
571 if (space > data_len)
573 while (space >= AES_BLOCK_LEN) {
574 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
575 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
576 data_len -= AES_BLOCK_LEN;
579 if (data_len <= 0) /* no more data */
582 if (m == NULL) { /* last buffer */
583 if (space != 0) /* short last block */
584 CCMP_DECRYPT(i, b, b0, pos, a, space);
593 * Block straddles buffers, split references. We
594 * do not handle splits that require >2 buffers
595 * since rx'd frames are never badly fragmented
596 * because drivers typically recv in clusters.
598 pos_next = mtod(m, uint8_t *);
599 len = min(data_len, AES_BLOCK_LEN);
600 space_next = len > space ? len - space : 0;
601 KASSERT(m->m_len >= space_next,
602 ("not enough data in following buffer, "
603 "m_len %u need %u\n", m->m_len, space_next));
605 xor_block(b+space, pos_next, space_next);
606 CCMP_DECRYPT(i, b, b0, pos, a, space);
607 xor_block(pos_next, b+space, space_next);
611 pos = pos_next + space_next;
612 space = m->m_len - space_next;
615 * Setup for next buffer.
617 pos = mtod(m, uint8_t *);
621 if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
622 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
623 "%s", "AES-CCM decrypt failed; MIC mismatch");
624 vap->iv_stats.is_rx_ccmpmic++;
634 IEEE80211_CRYPTO_MODULE(ccmp, 1);