1 | /*- |
2 | * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting |
3 | * All rights reserved. |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
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. |
15 | * |
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. |
19 | * |
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. |
30 | */ |
31 | |
32 | #include <sys/cdefs.h> |
33 | #ifdef __FreeBSD__ |
34 | __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto_ccmp.c,v 1.7 2005/07/11 03:06:23 sam Exp $" ); |
35 | #endif |
36 | #ifdef __NetBSD__ |
37 | __KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto_ccmp.c,v 1.11 2014/10/18 08:33:29 snj Exp $" ); |
38 | #endif |
39 | |
40 | /* |
41 | * IEEE 802.11i AES-CCMP crypto support. |
42 | * |
43 | * Part of this module is derived from similar code in the Host |
44 | * AP driver. The code is used with the consent of the author and |
45 | * its license is included below. |
46 | */ |
47 | #include <sys/param.h> |
48 | #include <sys/systm.h> |
49 | #include <sys/mbuf.h> |
50 | #include <sys/malloc.h> |
51 | #include <sys/kernel.h> |
52 | |
53 | #include <sys/socket.h> |
54 | |
55 | #include <net/if.h> |
56 | #include <net/if_ether.h> |
57 | #include <net/if_media.h> |
58 | |
59 | #include <net80211/ieee80211_var.h> |
60 | |
61 | #include <crypto/rijndael/rijndael.h> |
62 | |
63 | #define AES_BLOCK_LEN 16 |
64 | |
65 | struct ccmp_ctx { |
66 | struct ieee80211com *cc_ic; /* for diagnostics */ |
67 | rijndael_ctx cc_aes; |
68 | }; |
69 | |
70 | static void *ccmp_attach(struct ieee80211com *, struct ieee80211_key *); |
71 | static void ccmp_detach(struct ieee80211_key *); |
72 | static int ccmp_setkey(struct ieee80211_key *); |
73 | static int ccmp_encap(struct ieee80211_key *k, struct mbuf *, u_int8_t keyid); |
74 | static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); |
75 | static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); |
76 | static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); |
77 | |
78 | const struct ieee80211_cipher ieee80211_cipher_ccmp = { |
79 | .ic_name = "AES-CCM" , |
80 | .ic_cipher = IEEE80211_CIPHER_AES_CCM, |
81 | .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + |
82 | IEEE80211_WEP_EXTIVLEN, |
83 | .ic_trailer = IEEE80211_WEP_MICLEN, |
84 | .ic_miclen = 0, |
85 | .ic_attach = ccmp_attach, |
86 | .ic_detach = ccmp_detach, |
87 | .ic_setkey = ccmp_setkey, |
88 | .ic_encap = ccmp_encap, |
89 | .ic_decap = ccmp_decap, |
90 | .ic_enmic = ccmp_enmic, |
91 | .ic_demic = ccmp_demic, |
92 | }; |
93 | |
94 | #define ccmp ieee80211_cipher_ccmp |
95 | |
96 | static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); |
97 | static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, |
98 | struct mbuf *, int hdrlen); |
99 | |
100 | static void * |
101 | ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k) |
102 | { |
103 | struct ccmp_ctx *ctx; |
104 | |
105 | ctx = malloc(sizeof(struct ccmp_ctx), |
106 | M_DEVBUF, M_NOWAIT | M_ZERO); |
107 | if (ctx == NULL) { |
108 | ic->ic_stats.is_crypto_nomem++; |
109 | return NULL; |
110 | } |
111 | ctx->cc_ic = ic; |
112 | return ctx; |
113 | } |
114 | |
115 | static void |
116 | ccmp_detach(struct ieee80211_key *k) |
117 | { |
118 | struct ccmp_ctx *ctx = k->wk_private; |
119 | |
120 | free(ctx, M_DEVBUF); |
121 | } |
122 | |
123 | static int |
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_ic, 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_SWCRYPT) |
135 | rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY); |
136 | return 1; |
137 | } |
138 | |
139 | /* |
140 | * Add privacy headers appropriate for the specified key. |
141 | */ |
142 | static int |
143 | ccmp_encap(struct ieee80211_key *k, struct mbuf *m, u_int8_t keyid) |
144 | { |
145 | struct ccmp_ctx *ctx = k->wk_private; |
146 | struct ieee80211com *ic = ctx->cc_ic; |
147 | u_int8_t *ivp; |
148 | int hdrlen; |
149 | |
150 | hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); |
151 | |
152 | /* |
153 | * Copy down 802.11 header and add the IV, KeyID, and ExtIV. |
154 | */ |
155 | M_PREPEND(m, ccmp.ic_header, M_NOWAIT); |
156 | if (m == NULL) |
157 | return 0; |
158 | ivp = mtod(m, u_int8_t *); |
159 | ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen); |
160 | ivp += hdrlen; |
161 | |
162 | k->wk_keytsc++; /* XXX wrap at 48 bits */ |
163 | ivp[0] = k->wk_keytsc >> 0; /* PN0 */ |
164 | ivp[1] = k->wk_keytsc >> 8; /* PN1 */ |
165 | ivp[2] = 0; /* Reserved */ |
166 | ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ |
167 | ivp[4] = k->wk_keytsc >> 16; /* PN2 */ |
168 | ivp[5] = k->wk_keytsc >> 24; /* PN3 */ |
169 | ivp[6] = k->wk_keytsc >> 32; /* PN4 */ |
170 | ivp[7] = k->wk_keytsc >> 40; /* PN5 */ |
171 | |
172 | /* |
173 | * Finally, do software encrypt if neeed. |
174 | */ |
175 | if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && |
176 | !ccmp_encrypt(k, m, hdrlen)) |
177 | return 0; |
178 | |
179 | return 1; |
180 | } |
181 | |
182 | /* |
183 | * Add MIC to the frame as needed. |
184 | */ |
185 | static int |
186 | ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, |
187 | int force) |
188 | { |
189 | |
190 | return 1; |
191 | } |
192 | |
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) |
195 | { |
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; |
199 | } |
200 | |
201 | /* |
202 | * Validate and strip privacy headers (and trailer) for a |
203 | * received frame. The specified key should be correct but |
204 | * is also verified. |
205 | */ |
206 | static int |
207 | ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) |
208 | { |
209 | struct ccmp_ctx *ctx = k->wk_private; |
210 | struct ieee80211_frame *wh; |
211 | uint8_t *ivp; |
212 | uint64_t pn; |
213 | |
214 | /* |
215 | * Header should have extended IV and sequence number; |
216 | * verify the former and validate the latter. |
217 | */ |
218 | wh = mtod(m, struct ieee80211_frame *); |
219 | ivp = mtod(m, uint8_t *) + hdrlen; |
220 | if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { |
221 | /* |
222 | * No extended IV; discard frame. |
223 | */ |
224 | IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, |
225 | "[%s] Missing ExtIV for AES-CCM cipher\n" , |
226 | ether_sprintf(wh->i_addr2)); |
227 | ctx->cc_ic->ic_stats.is_rx_ccmpformat++; |
228 | return 0; |
229 | } |
230 | pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); |
231 | if (pn <= k->wk_keyrsc) { |
232 | /* |
233 | * Replay violation. |
234 | */ |
235 | ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn); |
236 | ctx->cc_ic->ic_stats.is_rx_ccmpreplay++; |
237 | return 0; |
238 | } |
239 | |
240 | /* |
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 |
245 | * decryption work. |
246 | */ |
247 | if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && |
248 | !ccmp_decrypt(k, pn, m, hdrlen)) |
249 | return 0; |
250 | |
251 | /* |
252 | * Copy up 802.11 header and strip crypto bits. |
253 | */ |
254 | ovbcopy(mtod(m, void *), mtod(m, u_int8_t *) + ccmp.ic_header, hdrlen); |
255 | m_adj(m, ccmp.ic_header); |
256 | m_adj(m, -ccmp.ic_trailer); |
257 | |
258 | /* |
259 | * Ok to update rsc now. |
260 | */ |
261 | k->wk_keyrsc = pn; |
262 | |
263 | return 1; |
264 | } |
265 | |
266 | /* |
267 | * Verify and strip MIC from the frame. |
268 | */ |
269 | static int |
270 | ccmp_demic(struct ieee80211_key *k, struct mbuf *m, |
271 | int force) |
272 | { |
273 | return 1; |
274 | } |
275 | |
276 | static __inline void |
277 | xor_block(uint8_t *b, const uint8_t *a, size_t len) |
278 | { |
279 | int i; |
280 | for (i = 0; i < len; i++) |
281 | b[i] ^= a[i]; |
282 | } |
283 | |
284 | /* |
285 | * Host AP crypt: host-based CCMP encryption implementation for Host AP driver |
286 | * |
287 | * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> |
288 | * |
289 | * This program is free software; you can redistribute it and/or modify |
290 | * it under the terms of the GNU General Public License version 2 as |
291 | * published by the Free Software Foundation. See README and COPYING for |
292 | * more details. |
293 | * |
294 | * Alternatively, this software may be distributed under the terms of BSD |
295 | * license. |
296 | */ |
297 | |
298 | static void |
299 | ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, |
300 | u_int64_t pn, size_t dlen, |
301 | uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], |
302 | uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) |
303 | { |
304 | #define IS_4ADDRESS(wh) \ |
305 | ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS) |
306 | #define IS_QOS_DATA(wh) ieee80211_has_qos(wh) |
307 | |
308 | /* CCM Initial Block: |
309 | * Flag (Include authentication header, M=3 (8-octet MIC), |
310 | * L=1 (2-octet Dlen)) |
311 | * Nonce: 0x00 | A2 | PN |
312 | * Dlen */ |
313 | b0[0] = 0x59; |
314 | /* NB: b0[1] set below */ |
315 | IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); |
316 | b0[8] = pn >> 40; |
317 | b0[9] = pn >> 32; |
318 | b0[10] = pn >> 24; |
319 | b0[11] = pn >> 16; |
320 | b0[12] = pn >> 8; |
321 | b0[13] = pn >> 0; |
322 | b0[14] = (dlen >> 8) & 0xff; |
323 | b0[15] = dlen & 0xff; |
324 | |
325 | /* AAD: |
326 | * FC with bits 4..6 and 11..13 masked to zero; 14 is always one |
327 | * A1 | A2 | A3 |
328 | * SC with bits 4..15 (seq#) masked to zero |
329 | * A4 (if present) |
330 | * QC (if present) |
331 | */ |
332 | aad[0] = 0; /* AAD length >> 8 */ |
333 | /* NB: aad[1] set below */ |
334 | aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ |
335 | aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ |
336 | /* NB: we know 3 addresses are contiguous */ |
337 | memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); |
338 | aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; |
339 | aad[23] = 0; /* all bits masked */ |
340 | /* |
341 | * Construct variable-length portion of AAD based |
342 | * on whether this is a 4-address frame/QOS frame. |
343 | * We always zero-pad to 32 bytes before running it |
344 | * through the cipher. |
345 | * |
346 | * We also fill in the priority bits of the CCM |
347 | * initial block as we know whether or not we have |
348 | * a QOS frame. |
349 | */ |
350 | if (IS_4ADDRESS(wh)) { |
351 | IEEE80211_ADDR_COPY(aad + 24, |
352 | ((struct ieee80211_frame_addr4 *)wh)->i_addr4); |
353 | if (IS_QOS_DATA(wh)) { |
354 | struct ieee80211_qosframe_addr4 *qwh4 = |
355 | (struct ieee80211_qosframe_addr4 *) wh; |
356 | aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ |
357 | aad[31] = 0; |
358 | b0[1] = aad[30]; |
359 | aad[1] = 22 + IEEE80211_ADDR_LEN + 2; |
360 | } else { |
361 | *(u_int16_t *)&aad[30] = 0; |
362 | b0[1] = 0; |
363 | aad[1] = 22 + IEEE80211_ADDR_LEN; |
364 | } |
365 | } else { |
366 | if (IS_QOS_DATA(wh)) { |
367 | struct ieee80211_qosframe *qwh = |
368 | (struct ieee80211_qosframe*) wh; |
369 | aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ |
370 | aad[25] = 0; |
371 | b0[1] = aad[24]; |
372 | aad[1] = 22 + 2; |
373 | } else { |
374 | *(u_int16_t *)&aad[24] = 0; |
375 | b0[1] = 0; |
376 | aad[1] = 22; |
377 | } |
378 | *(u_int16_t *)&aad[26] = 0; |
379 | *(u_int32_t *)&aad[28] = 0; |
380 | } |
381 | |
382 | /* Start with the first block and AAD */ |
383 | rijndael_encrypt(ctx, b0, auth); |
384 | xor_block(auth, aad, AES_BLOCK_LEN); |
385 | rijndael_encrypt(ctx, auth, auth); |
386 | xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); |
387 | rijndael_encrypt(ctx, auth, auth); |
388 | b0[0] &= 0x07; |
389 | b0[14] = b0[15] = 0; |
390 | rijndael_encrypt(ctx, b0, s0); |
391 | #undef IS_QOS_DATA |
392 | #undef IS_4ADDRESS |
393 | } |
394 | |
395 | #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ |
396 | /* Authentication */ \ |
397 | xor_block(_b, _pos, _len); \ |
398 | rijndael_encrypt(&ctx->cc_aes, _b, _b); \ |
399 | /* Encryption, with counter */ \ |
400 | _b0[14] = (_i >> 8) & 0xff; \ |
401 | _b0[15] = _i & 0xff; \ |
402 | rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ |
403 | xor_block(_pos, _e, _len); \ |
404 | } while (0) |
405 | |
406 | static int |
407 | ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) |
408 | { |
409 | struct ccmp_ctx *ctx = key->wk_private; |
410 | struct ieee80211_frame *wh; |
411 | struct mbuf *m = m0; |
412 | int data_len, i, space; |
413 | uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], |
414 | e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; |
415 | uint8_t *pos; |
416 | |
417 | ctx->cc_ic->ic_stats.is_crypto_ccmp++; |
418 | |
419 | wh = mtod(m, struct ieee80211_frame *); |
420 | data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); |
421 | ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, |
422 | data_len, b0, aad, b, s0); |
423 | |
424 | i = 1; |
425 | pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; |
426 | /* NB: assumes header is entirely in first mbuf */ |
427 | space = m->m_len - (hdrlen + ccmp.ic_header); |
428 | for (;;) { |
429 | if (space > data_len) |
430 | space = data_len; |
431 | /* |
432 | * Do full blocks. |
433 | */ |
434 | while (space >= AES_BLOCK_LEN) { |
435 | CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); |
436 | pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; |
437 | data_len -= AES_BLOCK_LEN; |
438 | i++; |
439 | } |
440 | if (data_len <= 0) /* no more data */ |
441 | break; |
442 | m = m->m_next; |
443 | if (m == NULL) { /* last buffer */ |
444 | if (space != 0) { |
445 | /* |
446 | * Short last block. |
447 | */ |
448 | CCMP_ENCRYPT(i, b, b0, pos, e, space); |
449 | } |
450 | break; |
451 | } |
452 | if (space != 0) { |
453 | uint8_t *pos_next; |
454 | int space_next; |
455 | int len, dl, sp; |
456 | struct mbuf *n; |
457 | |
458 | /* |
459 | * Block straddles one or more mbufs, gather data |
460 | * into the block buffer b, apply the cipher, then |
461 | * scatter the results back into the mbuf chain. |
462 | * The buffer will automatically get space bytes |
463 | * of data at offset 0 copied in+out by the |
464 | * CCMP_ENCRYPT request so we must take care of |
465 | * the remaining data. |
466 | */ |
467 | n = m; |
468 | dl = data_len; |
469 | sp = space; |
470 | for (;;) { |
471 | pos_next = mtod(n, uint8_t *); |
472 | len = min(dl, AES_BLOCK_LEN); |
473 | space_next = len > sp ? len - sp : 0; |
474 | if (n->m_len >= space_next) { |
475 | /* |
476 | * This mbuf has enough data; just grab |
477 | * what we need and stop. |
478 | */ |
479 | xor_block(b+sp, pos_next, space_next); |
480 | break; |
481 | } |
482 | /* |
483 | * This mbuf's contents are insufficient, |
484 | * take 'em all and prepare to advance to |
485 | * the next mbuf. |
486 | */ |
487 | xor_block(b+sp, pos_next, n->m_len); |
488 | sp += n->m_len, dl -= n->m_len; |
489 | n = n->m_next; |
490 | if (n == NULL) |
491 | break; |
492 | } |
493 | |
494 | CCMP_ENCRYPT(i, b, b0, pos, e, space); |
495 | |
496 | /* NB: just like above, but scatter data to mbufs */ |
497 | dl = data_len; |
498 | sp = space; |
499 | for (;;) { |
500 | pos_next = mtod(m, uint8_t *); |
501 | len = min(dl, AES_BLOCK_LEN); |
502 | space_next = len > sp ? len - sp : 0; |
503 | if (m->m_len >= space_next) { |
504 | xor_block(pos_next, e+sp, space_next); |
505 | break; |
506 | } |
507 | xor_block(pos_next, e+sp, m->m_len); |
508 | sp += m->m_len, dl -= m->m_len; |
509 | m = m->m_next; |
510 | if (m == NULL) |
511 | goto done; |
512 | } |
513 | /* |
514 | * Do bookkeeping. m now points to the last mbuf |
515 | * we grabbed data from. We know we consumed a |
516 | * full block of data as otherwise we'd have hit |
517 | * the end of the mbuf chain, so deduct from data_len. |
518 | * Otherwise advance the block number (i) and setup |
519 | * pos+space to reflect contents of the new mbuf. |
520 | */ |
521 | data_len -= AES_BLOCK_LEN; |
522 | i++; |
523 | pos = pos_next + space_next; |
524 | space = m->m_len - space_next; |
525 | } else { |
526 | /* |
527 | * Setup for next buffer. |
528 | */ |
529 | pos = mtod(m, uint8_t *); |
530 | space = m->m_len; |
531 | } |
532 | } |
533 | done: |
534 | /* tack on MIC */ |
535 | xor_block(b, s0, ccmp.ic_trailer); |
536 | return m_append(m0, ccmp.ic_trailer, b); |
537 | } |
538 | #undef CCMP_ENCRYPT |
539 | |
540 | #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ |
541 | /* Decrypt, with counter */ \ |
542 | _b0[14] = (_i >> 8) & 0xff; \ |
543 | _b0[15] = _i & 0xff; \ |
544 | rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ |
545 | xor_block(_pos, _b, _len); \ |
546 | /* Authentication */ \ |
547 | xor_block(_a, _pos, _len); \ |
548 | rijndael_encrypt(&ctx->cc_aes, _a, _a); \ |
549 | } while (0) |
550 | |
551 | static int |
552 | ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen) |
553 | { |
554 | struct ccmp_ctx *ctx = key->wk_private; |
555 | struct ieee80211_frame *wh; |
556 | uint8_t aad[2 * AES_BLOCK_LEN]; |
557 | uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; |
558 | uint8_t mic[AES_BLOCK_LEN]; |
559 | size_t data_len; |
560 | int i; |
561 | uint8_t *pos; |
562 | u_int space; |
563 | |
564 | ctx->cc_ic->ic_stats.is_crypto_ccmp++; |
565 | |
566 | wh = mtod(m, struct ieee80211_frame *); |
567 | data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer); |
568 | ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b); |
569 | m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic); |
570 | xor_block(mic, b, ccmp.ic_trailer); |
571 | |
572 | i = 1; |
573 | pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; |
574 | space = m->m_len - (hdrlen + ccmp.ic_header); |
575 | for (;;) { |
576 | if (space > data_len) |
577 | space = data_len; |
578 | while (space >= AES_BLOCK_LEN) { |
579 | CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); |
580 | pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; |
581 | data_len -= AES_BLOCK_LEN; |
582 | i++; |
583 | } |
584 | if (data_len <= 0) /* no more data */ |
585 | break; |
586 | m = m->m_next; |
587 | if (m == NULL) { /* last buffer */ |
588 | if (space != 0) /* short last block */ |
589 | CCMP_DECRYPT(i, b, b0, pos, a, space); |
590 | break; |
591 | } |
592 | if (space != 0) { |
593 | uint8_t *pos_next; |
594 | u_int space_next; |
595 | u_int len; |
596 | |
597 | /* |
598 | * Block straddles buffers, split references. We |
599 | * do not handle splits that require >2 buffers |
600 | * since rx'd frames are never badly fragmented |
601 | * because drivers typically recv in clusters. |
602 | */ |
603 | pos_next = mtod(m, uint8_t *); |
604 | len = min(data_len, AES_BLOCK_LEN); |
605 | space_next = len > space ? len - space : 0; |
606 | IASSERT(m->m_len >= space_next, |
607 | ("not enough data in following buffer, " |
608 | "m_len %u need %u\n" , m->m_len, space_next)); |
609 | |
610 | xor_block(b+space, pos_next, space_next); |
611 | CCMP_DECRYPT(i, b, b0, pos, a, space); |
612 | xor_block(pos_next, b+space, space_next); |
613 | data_len -= len; |
614 | i++; |
615 | |
616 | pos = pos_next + space_next; |
617 | space = m->m_len - space_next; |
618 | } else { |
619 | /* |
620 | * Setup for next buffer. |
621 | */ |
622 | pos = mtod(m, uint8_t *); |
623 | space = m->m_len; |
624 | } |
625 | } |
626 | if (memcmp(mic, a, ccmp.ic_trailer) != 0) { |
627 | IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, |
628 | "[%s] AES-CCM decrypt failed; MIC mismatch\n" , |
629 | ether_sprintf(wh->i_addr2)); |
630 | ctx->cc_ic->ic_stats.is_rx_ccmpmic++; |
631 | return 0; |
632 | } |
633 | return 1; |
634 | } |
635 | #undef CCMP_DECRYPT |
636 | |
637 | IEEE80211_CRYPTO_SETUP(ccmp_register) |
638 | { |
639 | ieee80211_crypto_register(&ccmp); |
640 | } |
641 | |