1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 /*
30 * IEEE 802.11i AES-CCMP crypto support.
31 *
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.
35 */
36 #include "opt_wlan.h"
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/mbuf.h>
41 #include <sys/malloc.h>
42 #include <sys/kernel.h>
43 #include <sys/module.h>
44
45 #include <sys/socket.h>
46
47 #include <net/if.h>
48 #include <net/if_media.h>
49 #include <net/ethernet.h>
50
51 #include <net80211/ieee80211_var.h>
52
53 #include <crypto/rijndael/rijndael.h>
54
55 #define AES_BLOCK_LEN 16
56
57 struct ccmp_ctx {
58 struct ieee80211vap *cc_vap; /* for diagnostics+statistics */
59 struct ieee80211com *cc_ic;
60 rijndael_ctx cc_aes;
61 };
62
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);
71
72 static const struct ieee80211_cipher ccmp = {
73 .ic_name = "AES-CCM",
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,
78 .ic_miclen = 0,
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,
87 };
88
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);
92
93 /* number of references from net80211 layer */
94 static int nrefs = 0;
95
96 static void *
ccmp_attach(struct ieee80211vap * vap,struct ieee80211_key * k)97 ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k)
98 {
99 struct ccmp_ctx *ctx;
100
101 ctx = (struct ccmp_ctx *) IEEE80211_MALLOC(sizeof(struct ccmp_ctx),
102 M_80211_CRYPTO, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
103 if (ctx == NULL) {
104 vap->iv_stats.is_crypto_nomem++;
105 return NULL;
106 }
107 ctx->cc_vap = vap;
108 ctx->cc_ic = vap->iv_ic;
109 nrefs++; /* NB: we assume caller locking */
110 return ctx;
111 }
112
113 static void
ccmp_detach(struct ieee80211_key * k)114 ccmp_detach(struct ieee80211_key *k)
115 {
116 struct ccmp_ctx *ctx = k->wk_private;
117
118 IEEE80211_FREE(ctx, M_80211_CRYPTO);
119 KASSERT(nrefs > 0, ("imbalanced attach/detach"));
120 nrefs--; /* NB: we assume caller locking */
121 }
122
123 static int
ccmp_setkey(struct ieee80211_key * k)124 ccmp_setkey(struct ieee80211_key *k)
125 {
126 struct ccmp_ctx *ctx = k->wk_private;
127
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);
132 return 0;
133 }
134 if (k->wk_flags & IEEE80211_KEY_SWENCRYPT)
135 rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY);
136 return 1;
137 }
138
139 static void
ccmp_setiv(struct ieee80211_key * k,uint8_t * ivp)140 ccmp_setiv(struct ieee80211_key *k, uint8_t *ivp)
141 {
142 struct ccmp_ctx *ctx = k->wk_private;
143 struct ieee80211vap *vap = ctx->cc_vap;
144 uint8_t keyid;
145
146 keyid = ieee80211_crypto_get_keyid(vap, k) << 6;
147
148 k->wk_keytsc++;
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 */
157 }
158
159 /*
160 * Add privacy headers appropriate for the specified key.
161 */
162 static int
ccmp_encap(struct ieee80211_key * k,struct mbuf * m)163 ccmp_encap(struct ieee80211_key *k, struct mbuf *m)
164 {
165 const struct ieee80211_frame *wh;
166 struct ccmp_ctx *ctx = k->wk_private;
167 struct ieee80211com *ic = ctx->cc_ic;
168 uint8_t *ivp;
169 int hdrlen;
170 int is_mgmt;
171
172 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
173 wh = mtod(m, const struct ieee80211_frame *);
174 is_mgmt = IEEE80211_IS_MGMT(wh);
175
176 /*
177 * Check to see if we need to insert IV/MIC.
178 *
179 * Some offload devices don't require the IV to be inserted
180 * as part of the hardware encryption.
181 */
182 if (is_mgmt && (k->wk_flags & IEEE80211_KEY_NOIVMGT))
183 return 1;
184 if ((! is_mgmt) && (k->wk_flags & IEEE80211_KEY_NOIV))
185 return 1;
186
187 /*
188 * Copy down 802.11 header and add the IV, KeyID, and ExtIV.
189 */
190 M_PREPEND(m, ccmp.ic_header, IEEE80211_M_NOWAIT);
191 if (m == NULL)
192 return 0;
193 ivp = mtod(m, uint8_t *);
194 ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
195 ivp += hdrlen;
196
197 ccmp_setiv(k, ivp);
198
199 /*
200 * Finally, do software encrypt if needed.
201 */
202 if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) &&
203 !ccmp_encrypt(k, m, hdrlen))
204 return 0;
205
206 return 1;
207 }
208
209 /*
210 * Add MIC to the frame as needed.
211 */
212 static int
ccmp_enmic(struct ieee80211_key * k,struct mbuf * m,int force)213 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force)
214 {
215
216 return 1;
217 }
218
219 static __inline uint64_t
READ_6(uint8_t b0,uint8_t b1,uint8_t b2,uint8_t b3,uint8_t b4,uint8_t b5)220 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
221 {
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;
225 }
226
227 /*
228 * Validate and strip privacy headers (and trailer) for a
229 * received frame. The specified key should be correct but
230 * is also verified.
231 */
232 static int
ccmp_decap(struct ieee80211_key * k,struct mbuf * m,int hdrlen)233 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen)
234 {
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;
239 uint8_t *ivp, tid;
240 uint64_t pn;
241 bool noreplaycheck;
242
243 rxs = ieee80211_get_rx_params_ptr(m);
244
245 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) != 0)
246 goto finish;
247
248 /*
249 * Header should have extended IV and sequence number;
250 * verify the former and validate the latter.
251 */
252 wh = mtod(m, struct ieee80211_frame *);
253 ivp = mtod(m, uint8_t *) + hdrlen;
254 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
255 /*
256 * No extended IV; discard frame.
257 */
258 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
259 "%s", "missing ExtIV for AES-CCM cipher");
260 vap->iv_stats.is_rx_ccmpformat++;
261 return 0;
262 }
263 tid = ieee80211_gettid(wh);
264 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
265
266 noreplaycheck = (k->wk_flags & IEEE80211_KEY_NOREPLAY) != 0;
267 noreplaycheck |= (rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_PN_VALIDATED) != 0;
268 if (pn <= k->wk_keyrsc[tid] && !noreplaycheck) {
269 /*
270 * Replay violation.
271 */
272 ieee80211_notify_replay_failure(vap, wh, k, pn, tid);
273 vap->iv_stats.is_rx_ccmpreplay++;
274 return 0;
275 }
276
277 /*
278 * Check if the device handled the decrypt in hardware.
279 * If so we just strip the header; otherwise we need to
280 * handle the decrypt in software. Note that for the
281 * latter we leave the header in place for use in the
282 * decryption work.
283 */
284 if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) &&
285 !ccmp_decrypt(k, pn, m, hdrlen))
286 return 0;
287
288 finish:
289 /*
290 * Copy up 802.11 header and strip crypto bits.
291 */
292 if (! ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP))) {
293 ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header,
294 hdrlen);
295 m_adj(m, ccmp.ic_header);
296 }
297
298 if ((rxs == NULL) || (rxs->c_pktflags & IEEE80211_RX_F_MIC_STRIP) == 0)
299 m_adj(m, -ccmp.ic_trailer);
300
301 /*
302 * Ok to update rsc now.
303 */
304 if ((rxs == NULL) || (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) == 0) {
305 /*
306 * Do not go backwards in the IEEE80211_KEY_NOREPLAY cases
307 * or in case hardware has checked but frames are arriving
308 * reordered (e.g., LinuxKPI drivers doing RSS which we are
309 * not prepared for at all).
310 */
311 if (pn > k->wk_keyrsc[tid])
312 k->wk_keyrsc[tid] = pn;
313 }
314
315 return 1;
316 }
317
318 /*
319 * Verify and strip MIC from the frame.
320 */
321 static int
ccmp_demic(struct ieee80211_key * k,struct mbuf * m,int force)322 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force)
323 {
324 return 1;
325 }
326
327 static __inline void
xor_block(uint8_t * b,const uint8_t * a,size_t len)328 xor_block(uint8_t *b, const uint8_t *a, size_t len)
329 {
330 int i;
331 for (i = 0; i < len; i++)
332 b[i] ^= a[i];
333 }
334
335 /*
336 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
337 *
338 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
339 *
340 * This program is free software; you can redistribute it and/or modify
341 * it under the terms of the GNU General Public License version 2 as
342 * published by the Free Software Foundation. See README and COPYING for
343 * more details.
344 *
345 * Alternatively, this software may be distributed under the terms of BSD
346 * license.
347 */
348
349 static void
ccmp_init_blocks(rijndael_ctx * ctx,struct ieee80211_frame * wh,u_int64_t pn,size_t dlen,uint8_t b0[AES_BLOCK_LEN],uint8_t aad[2* AES_BLOCK_LEN],uint8_t auth[AES_BLOCK_LEN],uint8_t s0[AES_BLOCK_LEN])350 ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh,
351 u_int64_t pn, size_t dlen,
352 uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
353 uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
354 {
355 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
356
357 /* CCM Initial Block:
358 * Flag (Include authentication header, M=3 (8-octet MIC),
359 * L=1 (2-octet Dlen))
360 * Nonce: 0x00 | A2 | PN
361 * Dlen */
362 b0[0] = 0x59;
363 /* NB: b0[1] set below */
364 IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
365 b0[8] = pn >> 40;
366 b0[9] = pn >> 32;
367 b0[10] = pn >> 24;
368 b0[11] = pn >> 16;
369 b0[12] = pn >> 8;
370 b0[13] = pn >> 0;
371 b0[14] = (dlen >> 8) & 0xff;
372 b0[15] = dlen & 0xff;
373
374 /* AAD:
375 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
376 * A1 | A2 | A3
377 * SC with bits 4..15 (seq#) masked to zero
378 * A4 (if present)
379 * QC (if present)
380 */
381 aad[0] = 0; /* AAD length >> 8 */
382 /* NB: aad[1] set below */
383 aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */
384 aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */
385 /* NB: we know 3 addresses are contiguous */
386 memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
387 aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
388 aad[23] = 0; /* all bits masked */
389 /*
390 * Construct variable-length portion of AAD based
391 * on whether this is a 4-address frame/QOS frame.
392 * We always zero-pad to 32 bytes before running it
393 * through the cipher.
394 *
395 * We also fill in the priority bits of the CCM
396 * initial block as we know whether or not we have
397 * a QOS frame.
398 */
399 if (IEEE80211_IS_DSTODS(wh)) {
400 IEEE80211_ADDR_COPY(aad + 24,
401 ((struct ieee80211_frame_addr4 *)wh)->i_addr4);
402 if (IS_QOS_DATA(wh)) {
403 struct ieee80211_qosframe_addr4 *qwh4 =
404 (struct ieee80211_qosframe_addr4 *) wh;
405 aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
406 aad[31] = 0;
407 b0[1] = aad[30];
408 aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
409 } else {
410 *(uint16_t *)&aad[30] = 0;
411 b0[1] = 0;
412 aad[1] = 22 + IEEE80211_ADDR_LEN;
413 }
414 } else {
415 if (IS_QOS_DATA(wh)) {
416 struct ieee80211_qosframe *qwh =
417 (struct ieee80211_qosframe*) wh;
418 aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
419 aad[25] = 0;
420 b0[1] = aad[24];
421 aad[1] = 22 + 2;
422 } else {
423 *(uint16_t *)&aad[24] = 0;
424 b0[1] = 0;
425 aad[1] = 22;
426 }
427 *(uint16_t *)&aad[26] = 0;
428 *(uint32_t *)&aad[28] = 0;
429 }
430
431 /* Start with the first block and AAD */
432 rijndael_encrypt(ctx, b0, auth);
433 xor_block(auth, aad, AES_BLOCK_LEN);
434 rijndael_encrypt(ctx, auth, auth);
435 xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
436 rijndael_encrypt(ctx, auth, auth);
437 b0[0] &= 0x07;
438 b0[14] = b0[15] = 0;
439 rijndael_encrypt(ctx, b0, s0);
440 #undef IS_QOS_DATA
441 }
442
443 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \
444 /* Authentication */ \
445 xor_block(_b, _pos, _len); \
446 rijndael_encrypt(&ctx->cc_aes, _b, _b); \
447 /* Encryption, with counter */ \
448 _b0[14] = (_i >> 8) & 0xff; \
449 _b0[15] = _i & 0xff; \
450 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \
451 xor_block(_pos, _e, _len); \
452 } while (0)
453
454 static int
ccmp_encrypt(struct ieee80211_key * key,struct mbuf * m0,int hdrlen)455 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen)
456 {
457 struct ccmp_ctx *ctx = key->wk_private;
458 struct ieee80211_frame *wh;
459 struct mbuf *m = m0;
460 int data_len, i, space;
461 uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN],
462 e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN];
463 uint8_t *pos;
464
465 ctx->cc_vap->iv_stats.is_crypto_ccmp++;
466
467 wh = mtod(m, struct ieee80211_frame *);
468 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
469 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
470 data_len, b0, aad, b, s0);
471
472 i = 1;
473 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
474 /* NB: assumes header is entirely in first mbuf */
475 space = m->m_len - (hdrlen + ccmp.ic_header);
476 for (;;) {
477 if (space > data_len)
478 space = data_len;
479 /*
480 * Do full blocks.
481 */
482 while (space >= AES_BLOCK_LEN) {
483 CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
484 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
485 data_len -= AES_BLOCK_LEN;
486 i++;
487 }
488 if (data_len <= 0) /* no more data */
489 break;
490 m = m->m_next;
491 if (m == NULL) { /* last buffer */
492 if (space != 0) {
493 /*
494 * Short last block.
495 */
496 CCMP_ENCRYPT(i, b, b0, pos, e, space);
497 }
498 break;
499 }
500 if (space != 0) {
501 uint8_t *pos_next;
502 int space_next;
503 int len, dl, sp;
504 struct mbuf *n;
505
506 /*
507 * Block straddles one or more mbufs, gather data
508 * into the block buffer b, apply the cipher, then
509 * scatter the results back into the mbuf chain.
510 * The buffer will automatically get space bytes
511 * of data at offset 0 copied in+out by the
512 * CCMP_ENCRYPT request so we must take care of
513 * the remaining data.
514 */
515 n = m;
516 dl = data_len;
517 sp = space;
518 for (;;) {
519 pos_next = mtod(n, uint8_t *);
520 len = min(dl, AES_BLOCK_LEN);
521 space_next = len > sp ? len - sp : 0;
522 if (n->m_len >= space_next) {
523 /*
524 * This mbuf has enough data; just grab
525 * what we need and stop.
526 */
527 xor_block(b+sp, pos_next, space_next);
528 break;
529 }
530 /*
531 * This mbuf's contents are insufficient,
532 * take 'em all and prepare to advance to
533 * the next mbuf.
534 */
535 xor_block(b+sp, pos_next, n->m_len);
536 sp += n->m_len, dl -= n->m_len;
537 n = n->m_next;
538 if (n == NULL)
539 break;
540 }
541
542 CCMP_ENCRYPT(i, b, b0, pos, e, space);
543
544 /* NB: just like above, but scatter data to mbufs */
545 dl = data_len;
546 sp = space;
547 for (;;) {
548 pos_next = mtod(m, uint8_t *);
549 len = min(dl, AES_BLOCK_LEN);
550 space_next = len > sp ? len - sp : 0;
551 if (m->m_len >= space_next) {
552 xor_block(pos_next, e+sp, space_next);
553 break;
554 }
555 xor_block(pos_next, e+sp, m->m_len);
556 sp += m->m_len, dl -= m->m_len;
557 m = m->m_next;
558 if (m == NULL)
559 goto done;
560 }
561 /*
562 * Do bookkeeping. m now points to the last mbuf
563 * we grabbed data from. We know we consumed a
564 * full block of data as otherwise we'd have hit
565 * the end of the mbuf chain, so deduct from data_len.
566 * Otherwise advance the block number (i) and setup
567 * pos+space to reflect contents of the new mbuf.
568 */
569 data_len -= AES_BLOCK_LEN;
570 i++;
571 pos = pos_next + space_next;
572 space = m->m_len - space_next;
573 } else {
574 /*
575 * Setup for next buffer.
576 */
577 pos = mtod(m, uint8_t *);
578 space = m->m_len;
579 }
580 }
581 done:
582 /* tack on MIC */
583 xor_block(b, s0, ccmp.ic_trailer);
584 return m_append(m0, ccmp.ic_trailer, b);
585 }
586 #undef CCMP_ENCRYPT
587
588 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
589 /* Decrypt, with counter */ \
590 _b0[14] = (_i >> 8) & 0xff; \
591 _b0[15] = _i & 0xff; \
592 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
593 xor_block(_pos, _b, _len); \
594 /* Authentication */ \
595 xor_block(_a, _pos, _len); \
596 rijndael_encrypt(&ctx->cc_aes, _a, _a); \
597 } while (0)
598
599 static int
ccmp_decrypt(struct ieee80211_key * key,u_int64_t pn,struct mbuf * m,int hdrlen)600 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen)
601 {
602 const struct ieee80211_rx_stats *rxs;
603 struct ccmp_ctx *ctx = key->wk_private;
604 struct ieee80211vap *vap = ctx->cc_vap;
605 struct ieee80211_frame *wh;
606 uint8_t aad[2 * AES_BLOCK_LEN];
607 uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
608 uint8_t mic[AES_BLOCK_LEN];
609 size_t data_len;
610 int i;
611 uint8_t *pos;
612 u_int space;
613
614 rxs = ieee80211_get_rx_params_ptr(m);
615 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED) != 0)
616 return (1);
617
618 ctx->cc_vap->iv_stats.is_crypto_ccmp++;
619
620 wh = mtod(m, struct ieee80211_frame *);
621 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
622 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
623 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic);
624 xor_block(mic, b, ccmp.ic_trailer);
625
626 i = 1;
627 pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
628 space = m->m_len - (hdrlen + ccmp.ic_header);
629 for (;;) {
630 if (space > data_len)
631 space = data_len;
632 while (space >= AES_BLOCK_LEN) {
633 CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
634 pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
635 data_len -= AES_BLOCK_LEN;
636 i++;
637 }
638 if (data_len <= 0) /* no more data */
639 break;
640 m = m->m_next;
641 if (m == NULL) { /* last buffer */
642 if (space != 0) /* short last block */
643 CCMP_DECRYPT(i, b, b0, pos, a, space);
644 break;
645 }
646 if (space != 0) {
647 uint8_t *pos_next;
648 u_int space_next;
649 u_int len;
650
651 /*
652 * Block straddles buffers, split references. We
653 * do not handle splits that require >2 buffers
654 * since rx'd frames are never badly fragmented
655 * because drivers typically recv in clusters.
656 */
657 pos_next = mtod(m, uint8_t *);
658 len = min(data_len, AES_BLOCK_LEN);
659 space_next = len > space ? len - space : 0;
660 KASSERT(m->m_len >= space_next,
661 ("not enough data in following buffer, "
662 "m_len %u need %u\n", m->m_len, space_next));
663
664 xor_block(b+space, pos_next, space_next);
665 CCMP_DECRYPT(i, b, b0, pos, a, space);
666 xor_block(pos_next, b+space, space_next);
667 data_len -= len;
668 i++;
669
670 pos = pos_next + space_next;
671 space = m->m_len - space_next;
672 } else {
673 /*
674 * Setup for next buffer.
675 */
676 pos = mtod(m, uint8_t *);
677 space = m->m_len;
678 }
679 }
680
681 /*
682 * If the MIC was stripped by HW/driver we are done.
683 */
684 if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_MIC_STRIP) != 0)
685 return (1);
686
687 if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
688 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
689 "%s", "AES-CCM decrypt failed; MIC mismatch");
690 vap->iv_stats.is_rx_ccmpmic++;
691 return 0;
692 }
693 return 1;
694 }
695 #undef CCMP_DECRYPT
696
697 /*
698 * Module glue.
699 */
700 IEEE80211_CRYPTO_MODULE(ccmp, 1);
701