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 void ccmp_setiv(struct ieee80211_key *, uint8_t *);
67 static int ccmp_encap(struct ieee80211_key *, struct mbuf *);
68 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int);
69 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int);
70 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int);
72 static const struct ieee80211_cipher ccmp = {
74 .ic_cipher = IEEE80211_CIPHER_AES_CCM,
75 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
76 IEEE80211_WEP_EXTIVLEN,
77 .ic_trailer = IEEE80211_WEP_MICLEN,
79 .ic_attach = ccmp_attach,
80 .ic_detach = ccmp_detach,
81 .ic_setkey = ccmp_setkey,
82 .ic_setiv = ccmp_setiv,
83 .ic_encap = ccmp_encap,
84 .ic_decap = ccmp_decap,
85 .ic_enmic = ccmp_enmic,
86 .ic_demic = ccmp_demic,
89 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen);
90 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn,
91 struct mbuf *, int hdrlen);
93 /* number of references from net80211 layer */
97 ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k)
101 ctx = (struct ccmp_ctx *) IEEE80211_MALLOC(sizeof(struct ccmp_ctx),
102 M_80211_CRYPTO, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
104 vap->iv_stats.is_crypto_nomem++;
108 ctx->cc_ic = vap->iv_ic;
109 nrefs++; /* NB: we assume caller locking */
114 ccmp_detach(struct ieee80211_key *k)
116 struct ccmp_ctx *ctx = k->wk_private;
118 IEEE80211_FREE(ctx, M_80211_CRYPTO);
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_vap, 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_SWENCRYPT)
135 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY);
140 ccmp_setiv(struct ieee80211_key *k, uint8_t *ivp)
142 struct ccmp_ctx *ctx = k->wk_private;
143 struct ieee80211vap *vap = ctx->cc_vap;
146 keyid = ieee80211_crypto_get_keyid(vap, k) << 6;
149 ivp[0] = k->wk_keytsc >> 0; /* PN0 */
150 ivp[1] = k->wk_keytsc >> 8; /* PN1 */
151 ivp[2] = 0; /* Reserved */
152 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */
153 ivp[4] = k->wk_keytsc >> 16; /* PN2 */
154 ivp[5] = k->wk_keytsc >> 24; /* PN3 */
155 ivp[6] = k->wk_keytsc >> 32; /* PN4 */
156 ivp[7] = k->wk_keytsc >> 40; /* PN5 */
160 * Add privacy headers appropriate for the specified key.
163 ccmp_encap(struct ieee80211_key *k, struct mbuf *m)
165 const struct ieee80211_frame *wh;
166 struct ccmp_ctx *ctx = k->wk_private;
167 struct ieee80211com *ic = ctx->cc_ic;
172 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
173 wh = mtod(m, const struct ieee80211_frame *);
174 is_mgmt = IEEE80211_IS_MGMT(wh);
177 * Check to see if we need to insert IV/MIC.
179 * Some offload devices don't require the IV to be inserted
180 * as part of the hardware encryption.
182 if (is_mgmt && (k->wk_flags & IEEE80211_KEY_NOIVMGT))
184 if ((! is_mgmt) && (k->wk_flags & IEEE80211_KEY_NOIV))
188 * Copy down 802.11 header and add the IV, KeyID, and ExtIV.
190 M_PREPEND(m, ccmp.ic_header, M_NOWAIT);
193 ivp = mtod(m, uint8_t *);
194 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
200 * Finally, do software encrypt if needed.
202 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) &&
203 !ccmp_encrypt(k, m, hdrlen))
210 * Add MIC to the frame as needed.
213 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force)
219 static __inline uint64_t
220 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
222 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
223 uint16_t iv16 = (b4 << 0) | (b5 << 8);
224 return (((uint64_t)iv16) << 32) | iv32;
228 * Validate and strip privacy headers (and trailer) for a
229 * received frame. The specified key should be correct but
233 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen)
235 const struct ieee80211_rx_stats *rxs;
236 struct ccmp_ctx *ctx = k->wk_private;
237 struct ieee80211vap *vap = ctx->cc_vap;
238 struct ieee80211_frame *wh;
242 rxs = ieee80211_get_rx_params_ptr(m);
244 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))
248 * Header should have extended IV and sequence number;
249 * verify the former and validate the latter.
251 wh = mtod(m, struct ieee80211_frame *);
252 ivp = mtod(m, uint8_t *) + hdrlen;
253 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
255 * No extended IV; discard frame.
257 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
258 "%s", "missing ExtIV for AES-CCM cipher");
259 vap->iv_stats.is_rx_ccmpformat++;
262 tid = ieee80211_gettid(wh);
263 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
264 if (pn <= k->wk_keyrsc[tid] &&
265 (k->wk_flags & IEEE80211_KEY_NOREPLAY) == 0) {
269 ieee80211_notify_replay_failure(vap, wh, k, pn, tid);
270 vap->iv_stats.is_rx_ccmpreplay++;
275 * Check if the device handled the decrypt in hardware.
276 * If so we just strip the header; otherwise we need to
277 * handle the decrypt in software. Note that for the
278 * latter we leave the header in place for use in the
281 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) &&
282 !ccmp_decrypt(k, pn, m, hdrlen))
287 * Copy up 802.11 header and strip crypto bits.
289 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) {
290 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header,
292 m_adj(m, ccmp.ic_header);
296 * XXX TODO: see if MMIC_STRIP also covers CCMP MIC trailer.
298 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP)))
299 m_adj(m, -ccmp.ic_trailer);
302 * Ok to update rsc now.
304 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) {
305 k->wk_keyrsc[tid] = pn;
312 * Verify and strip MIC from the frame.
315 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force)
321 xor_block(uint8_t *b, const uint8_t *a, size_t len)
324 for (i = 0; i < len; i++)
329 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
331 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
333 * This program is free software; you can redistribute it and/or modify
334 * it under the terms of the GNU General Public License version 2 as
335 * published by the Free Software Foundation. See README and COPYING for
338 * Alternatively, this software may be distributed under the terms of BSD
343 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh,
344 u_int64_t pn, size_t dlen,
345 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
346 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
348 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
350 /* CCM Initial Block:
351 * Flag (Include authentication header, M=3 (8-octet MIC),
352 * L=1 (2-octet Dlen))
353 * Nonce: 0x00 | A2 | PN
356 /* NB: b0[1] set below */
357 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
364 b0[14] = (dlen >> 8) & 0xff;
365 b0[15] = dlen & 0xff;
368 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
370 * SC with bits 4..15 (seq#) masked to zero
374 aad[0] = 0; /* AAD length >> 8 */
375 /* NB: aad[1] set below */
376 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */
377 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */
378 /* NB: we know 3 addresses are contiguous */
379 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
380 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
381 aad[23] = 0; /* all bits masked */
383 * Construct variable-length portion of AAD based
384 * on whether this is a 4-address frame/QOS frame.
385 * We always zero-pad to 32 bytes before running it
386 * through the cipher.
388 * We also fill in the priority bits of the CCM
389 * initial block as we know whether or not we have
392 if (IEEE80211_IS_DSTODS(wh)) {
393 IEEE80211_ADDR_COPY(aad + 24,
394 ((struct ieee80211_frame_addr4 *)wh)->i_addr4);
395 if (IS_QOS_DATA(wh)) {
396 struct ieee80211_qosframe_addr4 *qwh4 =
397 (struct ieee80211_qosframe_addr4 *) wh;
398 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
401 aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
403 *(uint16_t *)&aad[30] = 0;
405 aad[1] = 22 + IEEE80211_ADDR_LEN;
408 if (IS_QOS_DATA(wh)) {
409 struct ieee80211_qosframe *qwh =
410 (struct ieee80211_qosframe*) wh;
411 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
416 *(uint16_t *)&aad[24] = 0;
420 *(uint16_t *)&aad[26] = 0;
421 *(uint32_t *)&aad[28] = 0;
424 /* Start with the first block and AAD */
425 rijndael_encrypt(ctx, b0, auth);
426 xor_block(auth, aad, AES_BLOCK_LEN);
427 rijndael_encrypt(ctx, auth, auth);
428 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
429 rijndael_encrypt(ctx, auth, auth);
432 rijndael_encrypt(ctx, b0, s0);
436 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \
437 /* Authentication */ \
438 xor_block(_b, _pos, _len); \
439 rijndael_encrypt(&ctx->cc_aes, _b, _b); \
440 /* Encryption, with counter */ \
441 _b0[14] = (_i >> 8) & 0xff; \
442 _b0[15] = _i & 0xff; \
443 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \
444 xor_block(_pos, _e, _len); \
448 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen)
450 struct ccmp_ctx *ctx = key->wk_private;
451 struct ieee80211_frame *wh;
453 int data_len, i, space;
454 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN],
455 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN];
458 ctx->cc_vap->iv_stats.is_crypto_ccmp++;
460 wh = mtod(m, struct ieee80211_frame *);
461 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
462 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
463 data_len, b0, aad, b, s0);
466 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
467 /* NB: assumes header is entirely in first mbuf */
468 space = m->m_len - (hdrlen + ccmp.ic_header);
470 if (space > data_len)
475 while (space >= AES_BLOCK_LEN) {
476 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
477 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
478 data_len -= AES_BLOCK_LEN;
481 if (data_len <= 0) /* no more data */
484 if (m == NULL) { /* last buffer */
489 CCMP_ENCRYPT(i, b, b0, pos, e, space);
500 * Block straddles one or more mbufs, gather data
501 * into the block buffer b, apply the cipher, then
502 * scatter the results back into the mbuf chain.
503 * The buffer will automatically get space bytes
504 * of data at offset 0 copied in+out by the
505 * CCMP_ENCRYPT request so we must take care of
506 * the remaining data.
512 pos_next = mtod(n, uint8_t *);
513 len = min(dl, AES_BLOCK_LEN);
514 space_next = len > sp ? len - sp : 0;
515 if (n->m_len >= space_next) {
517 * This mbuf has enough data; just grab
518 * what we need and stop.
520 xor_block(b+sp, pos_next, space_next);
524 * This mbuf's contents are insufficient,
525 * take 'em all and prepare to advance to
528 xor_block(b+sp, pos_next, n->m_len);
529 sp += n->m_len, dl -= n->m_len;
535 CCMP_ENCRYPT(i, b, b0, pos, e, space);
537 /* NB: just like above, but scatter data to mbufs */
541 pos_next = mtod(m, uint8_t *);
542 len = min(dl, AES_BLOCK_LEN);
543 space_next = len > sp ? len - sp : 0;
544 if (m->m_len >= space_next) {
545 xor_block(pos_next, e+sp, space_next);
548 xor_block(pos_next, e+sp, m->m_len);
549 sp += m->m_len, dl -= m->m_len;
555 * Do bookkeeping. m now points to the last mbuf
556 * we grabbed data from. We know we consumed a
557 * full block of data as otherwise we'd have hit
558 * the end of the mbuf chain, so deduct from data_len.
559 * Otherwise advance the block number (i) and setup
560 * pos+space to reflect contents of the new mbuf.
562 data_len -= AES_BLOCK_LEN;
564 pos = pos_next + space_next;
565 space = m->m_len - space_next;
568 * Setup for next buffer.
570 pos = mtod(m, uint8_t *);
576 xor_block(b, s0, ccmp.ic_trailer);
577 return m_append(m0, ccmp.ic_trailer, b);
581 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
582 /* Decrypt, with counter */ \
583 _b0[14] = (_i >> 8) & 0xff; \
584 _b0[15] = _i & 0xff; \
585 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
586 xor_block(_pos, _b, _len); \
587 /* Authentication */ \
588 xor_block(_a, _pos, _len); \
589 rijndael_encrypt(&ctx->cc_aes, _a, _a); \
593 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen)
595 struct ccmp_ctx *ctx = key->wk_private;
596 struct ieee80211vap *vap = ctx->cc_vap;
597 struct ieee80211_frame *wh;
598 uint8_t aad[2 * AES_BLOCK_LEN];
599 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
600 uint8_t mic[AES_BLOCK_LEN];
606 ctx->cc_vap->iv_stats.is_crypto_ccmp++;
608 wh = mtod(m, struct ieee80211_frame *);
609 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
610 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
611 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic);
612 xor_block(mic, b, ccmp.ic_trailer);
615 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
616 space = m->m_len - (hdrlen + ccmp.ic_header);
618 if (space > data_len)
620 while (space >= AES_BLOCK_LEN) {
621 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
622 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
623 data_len -= AES_BLOCK_LEN;
626 if (data_len <= 0) /* no more data */
629 if (m == NULL) { /* last buffer */
630 if (space != 0) /* short last block */
631 CCMP_DECRYPT(i, b, b0, pos, a, space);
640 * Block straddles buffers, split references. We
641 * do not handle splits that require >2 buffers
642 * since rx'd frames are never badly fragmented
643 * because drivers typically recv in clusters.
645 pos_next = mtod(m, uint8_t *);
646 len = min(data_len, AES_BLOCK_LEN);
647 space_next = len > space ? len - space : 0;
648 KASSERT(m->m_len >= space_next,
649 ("not enough data in following buffer, "
650 "m_len %u need %u\n", m->m_len, space_next));
652 xor_block(b+space, pos_next, space_next);
653 CCMP_DECRYPT(i, b, b0, pos, a, space);
654 xor_block(pos_next, b+space, space_next);
658 pos = pos_next + space_next;
659 space = m->m_len - space_next;
662 * Setup for next buffer.
664 pos = mtod(m, uint8_t *);
668 if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
669 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
670 "%s", "AES-CCM decrypt failed; MIC mismatch");
671 vap->iv_stats.is_rx_ccmpmic++;
681 IEEE80211_CRYPTO_MODULE(ccmp, 1);