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
] &&
230 (k
->wk_flags
& IEEE80211_KEY_NOREPLAY
) == 0) {
234 ieee80211_notify_replay_failure(vap
, wh
, k
, pn
, tid
);
235 vap
->iv_stats
.is_rx_ccmpreplay
++;
240 * Check if the device handled the decrypt in hardware.
241 * If so we just strip the header; otherwise we need to
242 * handle the decrypt in software. Note that for the
243 * latter we leave the header in place for use in the
246 if ((k
->wk_flags
& IEEE80211_KEY_SWDECRYPT
) &&
247 !ccmp_decrypt(k
, pn
, m
, hdrlen
))
251 * Copy up 802.11 header and strip crypto bits.
253 ovbcopy(mtod(m
, void *), mtod(m
, uint8_t *) + ccmp
.ic_header
, hdrlen
);
254 m_adj(m
, ccmp
.ic_header
);
255 m_adj(m
, -ccmp
.ic_trailer
);
258 * Ok to update rsc now.
260 k
->wk_keyrsc
[tid
] = pn
;
266 * Verify and strip MIC from the frame.
269 ccmp_demic(struct ieee80211_key
*k
, struct mbuf
*m
, int force
)
275 xor_block(uint8_t *b
, const uint8_t *a
, size_t len
)
278 for (i
= 0; i
< len
; i
++)
283 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver
285 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
287 * This program is free software; you can redistribute it and/or modify
288 * it under the terms of the GNU General Public License version 2 as
289 * published by the Free Software Foundation. See README and COPYING for
292 * Alternatively, this software may be distributed under the terms of BSD
297 ccmp_init_blocks(rijndael_ctx
*ctx
, struct ieee80211_frame
*wh
,
298 u_int64_t pn
, size_t dlen
,
299 uint8_t b0
[AES_BLOCK_LEN
], uint8_t aad
[2 * AES_BLOCK_LEN
],
300 uint8_t auth
[AES_BLOCK_LEN
], uint8_t s0
[AES_BLOCK_LEN
])
302 #define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
304 /* CCM Initial Block:
305 * Flag (Include authentication header, M=3 (8-octet MIC),
306 * L=1 (2-octet Dlen))
307 * Nonce: 0x00 | A2 | PN
310 /* NB: b0[1] set below */
311 IEEE80211_ADDR_COPY(b0
+ 2, wh
->i_addr2
);
318 b0
[14] = (dlen
>> 8) & 0xff;
319 b0
[15] = dlen
& 0xff;
322 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
324 * SC with bits 4..15 (seq#) masked to zero
328 aad
[0] = 0; /* AAD length >> 8 */
329 /* NB: aad[1] set below */
330 aad
[2] = wh
->i_fc
[0] & 0x8f; /* XXX magic #s */
331 aad
[3] = wh
->i_fc
[1] & 0xc7; /* XXX magic #s */
332 /* NB: we know 3 addresses are contiguous */
333 memcpy(aad
+ 4, wh
->i_addr1
, 3 * IEEE80211_ADDR_LEN
);
334 aad
[22] = wh
->i_seq
[0] & IEEE80211_SEQ_FRAG_MASK
;
335 aad
[23] = 0; /* all bits masked */
337 * Construct variable-length portion of AAD based
338 * on whether this is a 4-address frame/QOS frame.
339 * We always zero-pad to 32 bytes before running it
340 * through the cipher.
342 * We also fill in the priority bits of the CCM
343 * initial block as we know whether or not we have
346 if (IEEE80211_IS_DSTODS(wh
)) {
347 IEEE80211_ADDR_COPY(aad
+ 24,
348 ((struct ieee80211_frame_addr4
*)wh
)->i_addr4
);
349 if (IS_QOS_DATA(wh
)) {
350 struct ieee80211_qosframe_addr4
*qwh4
=
351 (struct ieee80211_qosframe_addr4
*) wh
;
352 aad
[30] = qwh4
->i_qos
[0] & 0x0f;/* just priority bits */
355 aad
[1] = 22 + IEEE80211_ADDR_LEN
+ 2;
357 *(uint16_t *)&aad
[30] = 0;
359 aad
[1] = 22 + IEEE80211_ADDR_LEN
;
362 if (IS_QOS_DATA(wh
)) {
363 struct ieee80211_qosframe
*qwh
=
364 (struct ieee80211_qosframe
*) wh
;
365 aad
[24] = qwh
->i_qos
[0] & 0x0f; /* just priority bits */
370 *(uint16_t *)&aad
[24] = 0;
374 *(uint16_t *)&aad
[26] = 0;
375 *(uint32_t *)&aad
[28] = 0;
378 /* Start with the first block and AAD */
379 rijndael_encrypt(ctx
, b0
, auth
);
380 xor_block(auth
, aad
, AES_BLOCK_LEN
);
381 rijndael_encrypt(ctx
, auth
, auth
);
382 xor_block(auth
, &aad
[AES_BLOCK_LEN
], AES_BLOCK_LEN
);
383 rijndael_encrypt(ctx
, auth
, auth
);
386 rijndael_encrypt(ctx
, b0
, s0
);
390 #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \
391 /* Authentication */ \
392 xor_block(_b, _pos, _len); \
393 rijndael_encrypt(&ctx->cc_aes, _b, _b); \
394 /* Encryption, with counter */ \
395 _b0[14] = (_i >> 8) & 0xff; \
396 _b0[15] = _i & 0xff; \
397 rijndael_encrypt(&ctx->cc_aes, _b0, _e); \
398 xor_block(_pos, _e, _len); \
402 ccmp_encrypt(struct ieee80211_key
*key
, struct mbuf
*m0
, int hdrlen
)
404 struct ccmp_ctx
*ctx
= key
->wk_private
;
405 struct ieee80211_frame
*wh
;
407 int data_len
, i
, space
;
408 uint8_t aad
[2 * AES_BLOCK_LEN
], b0
[AES_BLOCK_LEN
], b
[AES_BLOCK_LEN
],
409 e
[AES_BLOCK_LEN
], s0
[AES_BLOCK_LEN
];
412 ctx
->cc_vap
->iv_stats
.is_crypto_ccmp
++;
414 wh
= mtod(m
, struct ieee80211_frame
*);
415 data_len
= m
->m_pkthdr
.len
- (hdrlen
+ ccmp
.ic_header
);
416 ccmp_init_blocks(&ctx
->cc_aes
, wh
, key
->wk_keytsc
,
417 data_len
, b0
, aad
, b
, s0
);
420 pos
= mtod(m
, uint8_t *) + hdrlen
+ ccmp
.ic_header
;
421 /* NB: assumes header is entirely in first mbuf */
422 space
= m
->m_len
- (hdrlen
+ ccmp
.ic_header
);
424 if (space
> data_len
)
429 while (space
>= AES_BLOCK_LEN
) {
430 CCMP_ENCRYPT(i
, b
, b0
, pos
, e
, AES_BLOCK_LEN
);
431 pos
+= AES_BLOCK_LEN
, space
-= AES_BLOCK_LEN
;
432 data_len
-= AES_BLOCK_LEN
;
435 if (data_len
<= 0) /* no more data */
438 if (m
== NULL
) { /* last buffer */
443 CCMP_ENCRYPT(i
, b
, b0
, pos
, e
, space
);
454 * Block straddles one or more mbufs, gather data
455 * into the block buffer b, apply the cipher, then
456 * scatter the results back into the mbuf chain.
457 * The buffer will automatically get space bytes
458 * of data at offset 0 copied in+out by the
459 * CCMP_ENCRYPT request so we must take care of
460 * the remaining data.
466 pos_next
= mtod(n
, uint8_t *);
467 len
= min(dl
, AES_BLOCK_LEN
);
468 space_next
= len
> sp
? len
- sp
: 0;
469 if (n
->m_len
>= space_next
) {
471 * This mbuf has enough data; just grab
472 * what we need and stop.
474 xor_block(b
+sp
, pos_next
, space_next
);
478 * This mbuf's contents are insufficient,
479 * take 'em all and prepare to advance to
482 xor_block(b
+sp
, pos_next
, n
->m_len
);
483 sp
+= n
->m_len
, dl
-= n
->m_len
;
489 CCMP_ENCRYPT(i
, b
, b0
, pos
, e
, space
);
491 /* NB: just like above, but scatter data to mbufs */
495 pos_next
= mtod(m
, uint8_t *);
496 len
= min(dl
, AES_BLOCK_LEN
);
497 space_next
= len
> sp
? len
- sp
: 0;
498 if (m
->m_len
>= space_next
) {
499 xor_block(pos_next
, e
+sp
, space_next
);
502 xor_block(pos_next
, e
+sp
, m
->m_len
);
503 sp
+= m
->m_len
, dl
-= m
->m_len
;
509 * Do bookkeeping. m now points to the last mbuf
510 * we grabbed data from. We know we consumed a
511 * full block of data as otherwise we'd have hit
512 * the end of the mbuf chain, so deduct from data_len.
513 * Otherwise advance the block number (i) and setup
514 * pos+space to reflect contents of the new mbuf.
516 data_len
-= AES_BLOCK_LEN
;
518 pos
= pos_next
+ space_next
;
519 space
= m
->m_len
- space_next
;
522 * Setup for next buffer.
524 pos
= mtod(m
, uint8_t *);
530 xor_block(b
, s0
, ccmp
.ic_trailer
);
531 return m_append(m0
, ccmp
.ic_trailer
, b
);
535 #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
536 /* Decrypt, with counter */ \
537 _b0[14] = (_i >> 8) & 0xff; \
538 _b0[15] = _i & 0xff; \
539 rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
540 xor_block(_pos, _b, _len); \
541 /* Authentication */ \
542 xor_block(_a, _pos, _len); \
543 rijndael_encrypt(&ctx->cc_aes, _a, _a); \
547 ccmp_decrypt(struct ieee80211_key
*key
, u_int64_t pn
, struct mbuf
*m
, int hdrlen
)
549 struct ccmp_ctx
*ctx
= key
->wk_private
;
550 struct ieee80211vap
*vap
= ctx
->cc_vap
;
551 struct ieee80211_frame
*wh
;
552 uint8_t aad
[2 * AES_BLOCK_LEN
];
553 uint8_t b0
[AES_BLOCK_LEN
], b
[AES_BLOCK_LEN
], a
[AES_BLOCK_LEN
];
554 uint8_t mic
[AES_BLOCK_LEN
];
560 ctx
->cc_vap
->iv_stats
.is_crypto_ccmp
++;
562 wh
= mtod(m
, struct ieee80211_frame
*);
563 data_len
= m
->m_pkthdr
.len
- (hdrlen
+ ccmp
.ic_header
+ ccmp
.ic_trailer
);
564 ccmp_init_blocks(&ctx
->cc_aes
, wh
, pn
, data_len
, b0
, aad
, a
, b
);
565 m_copydata(m
, m
->m_pkthdr
.len
- ccmp
.ic_trailer
, ccmp
.ic_trailer
, mic
);
566 xor_block(mic
, b
, ccmp
.ic_trailer
);
569 pos
= mtod(m
, uint8_t *) + hdrlen
+ ccmp
.ic_header
;
570 space
= m
->m_len
- (hdrlen
+ ccmp
.ic_header
);
572 if (space
> data_len
)
574 while (space
>= AES_BLOCK_LEN
) {
575 CCMP_DECRYPT(i
, b
, b0
, pos
, a
, AES_BLOCK_LEN
);
576 pos
+= AES_BLOCK_LEN
, space
-= AES_BLOCK_LEN
;
577 data_len
-= AES_BLOCK_LEN
;
580 if (data_len
<= 0) /* no more data */
583 if (m
== NULL
) { /* last buffer */
584 if (space
!= 0) /* short last block */
585 CCMP_DECRYPT(i
, b
, b0
, pos
, a
, space
);
594 * Block straddles buffers, split references. We
595 * do not handle splits that require >2 buffers
596 * since rx'd frames are never badly fragmented
597 * because drivers typically recv in clusters.
599 pos_next
= mtod(m
, uint8_t *);
600 len
= min(data_len
, AES_BLOCK_LEN
);
601 space_next
= len
> space
? len
- space
: 0;
602 KASSERT(m
->m_len
>= space_next
,
603 ("not enough data in following buffer, "
604 "m_len %u need %u\n", m
->m_len
, space_next
));
606 xor_block(b
+space
, pos_next
, space_next
);
607 CCMP_DECRYPT(i
, b
, b0
, pos
, a
, space
);
608 xor_block(pos_next
, b
+space
, space_next
);
612 pos
= pos_next
+ space_next
;
613 space
= m
->m_len
- space_next
;
616 * Setup for next buffer.
618 pos
= mtod(m
, uint8_t *);
622 if (memcmp(mic
, a
, ccmp
.ic_trailer
) != 0) {
623 IEEE80211_NOTE_MAC(vap
, IEEE80211_MSG_CRYPTO
, wh
->i_addr2
,
624 "%s", "AES-CCM decrypt failed; MIC mismatch");
625 vap
->iv_stats
.is_rx_ccmpmic
++;
635 IEEE80211_CRYPTO_MODULE(ccmp
, 1);