1 /*
2 * Copyright 2002-2004, Instant802 Networks, Inc.
3 * Copyright 2008, Jouni Malinen <j@w1.fi>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10 #include <linux/netdevice.h>
11 #include <linux/types.h>
12 #include <linux/skbuff.h>
13 #include <linux/compiler.h>
14 #include <linux/ieee80211.h>
15 #include <linux/gfp.h>
16 #include <asm/unaligned.h>
17 #include <net/mac80211.h>
18 #include <crypto/aes.h>
19
20 #include "ieee80211_i.h"
21 #include "michael.h"
22 #include "tkip.h"
23 #include "aes_ccm.h"
24 #include "aes_cmac.h"
25 #include "wpa.h"
26
27 ieee80211_tx_result
ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data * tx)28 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
29 {
30 u8 *data, *key, *mic;
31 size_t data_len;
32 unsigned int hdrlen;
33 struct ieee80211_hdr *hdr;
34 struct sk_buff *skb = tx->skb;
35 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
36 int tail;
37
38 hdr = (struct ieee80211_hdr *)skb->data;
39 if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
40 skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control))
41 return TX_CONTINUE;
42
43 hdrlen = ieee80211_hdrlen(hdr->frame_control);
44 if (skb->len < hdrlen)
45 return TX_DROP;
46
47 data = skb->data + hdrlen;
48 data_len = skb->len - hdrlen;
49
50 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) {
51 /* Need to use software crypto for the test */
52 info->control.hw_key = NULL;
53 }
54
55 if (info->control.hw_key &&
56 (info->flags & IEEE80211_TX_CTL_DONTFRAG ||
57 tx->local->ops->set_frag_threshold) &&
58 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
59 /* hwaccel - with no need for SW-generated MMIC */
60 return TX_CONTINUE;
61 }
62
63 tail = MICHAEL_MIC_LEN;
64 if (!info->control.hw_key)
65 tail += TKIP_ICV_LEN;
66
67 if (WARN_ON(skb_tailroom(skb) < tail ||
68 skb_headroom(skb) < TKIP_IV_LEN))
69 return TX_DROP;
70
71 key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY];
72 mic = skb_put(skb, MICHAEL_MIC_LEN);
73 michael_mic(key, hdr, data, data_len, mic);
74 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE))
75 mic[0]++;
76
77 return TX_CONTINUE;
78 }
79
80
81 ieee80211_rx_result
ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data * rx)82 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
83 {
84 u8 *data, *key = NULL;
85 size_t data_len;
86 unsigned int hdrlen;
87 u8 mic[MICHAEL_MIC_LEN];
88 struct sk_buff *skb = rx->skb;
89 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
90 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
91
92 /*
93 * it makes no sense to check for MIC errors on anything other
94 * than data frames.
95 */
96 if (!ieee80211_is_data_present(hdr->frame_control))
97 return RX_CONTINUE;
98
99 /*
100 * No way to verify the MIC if the hardware stripped it or
101 * the IV with the key index. In this case we have solely rely
102 * on the driver to set RX_FLAG_MMIC_ERROR in the event of a
103 * MIC failure report.
104 */
105 if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) {
106 if (status->flag & RX_FLAG_MMIC_ERROR)
107 goto mic_fail;
108
109 if (!(status->flag & RX_FLAG_IV_STRIPPED) && rx->key &&
110 rx->key->conf.cipher == WLAN_CIPHER_SUITE_TKIP)
111 goto update_iv;
112
113 return RX_CONTINUE;
114 }
115
116 /*
117 * Some hardware seems to generate Michael MIC failure reports; even
118 * though, the frame was not encrypted with TKIP and therefore has no
119 * MIC. Ignore the flag them to avoid triggering countermeasures.
120 */
121 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
122 !(status->flag & RX_FLAG_DECRYPTED))
123 return RX_CONTINUE;
124
125 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
126 /*
127 * APs with pairwise keys should never receive Michael MIC
128 * errors for non-zero keyidx because these are reserved for
129 * group keys and only the AP is sending real multicast
130 * frames in the BSS. (
131 */
132 return RX_DROP_UNUSABLE;
133 }
134
135 if (status->flag & RX_FLAG_MMIC_ERROR)
136 goto mic_fail;
137
138 hdrlen = ieee80211_hdrlen(hdr->frame_control);
139 if (skb->len < hdrlen + MICHAEL_MIC_LEN)
140 return RX_DROP_UNUSABLE;
141
142 if (skb_linearize(rx->skb))
143 return RX_DROP_UNUSABLE;
144 hdr = (void *)skb->data;
145
146 data = skb->data + hdrlen;
147 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
148 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
149 michael_mic(key, hdr, data, data_len, mic);
150 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
151 goto mic_fail;
152
153 /* remove Michael MIC from payload */
154 skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
155
156 update_iv:
157 /* update IV in key information to be able to detect replays */
158 rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32;
159 rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
160
161 return RX_CONTINUE;
162
163 mic_fail:
164 /*
165 * In some cases the key can be unset - e.g. a multicast packet, in
166 * a driver that supports HW encryption. Send up the key idx only if
167 * the key is set.
168 */
169 mac80211_ev_michael_mic_failure(rx->sdata,
170 rx->key ? rx->key->conf.keyidx : -1,
171 (void *) skb->data, NULL, GFP_ATOMIC);
172 return RX_DROP_UNUSABLE;
173 }
174
175
tkip_encrypt_skb(struct ieee80211_tx_data * tx,struct sk_buff * skb)176 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
177 {
178 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
179 struct ieee80211_key *key = tx->key;
180 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
181 unsigned long flags;
182 unsigned int hdrlen;
183 int len, tail;
184 u8 *pos;
185
186 if (info->control.hw_key &&
187 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
188 /* hwaccel - with no need for software-generated IV */
189 return 0;
190 }
191
192 hdrlen = ieee80211_hdrlen(hdr->frame_control);
193 len = skb->len - hdrlen;
194
195 if (info->control.hw_key)
196 tail = 0;
197 else
198 tail = TKIP_ICV_LEN;
199
200 if (WARN_ON(skb_tailroom(skb) < tail ||
201 skb_headroom(skb) < TKIP_IV_LEN))
202 return -1;
203
204 pos = skb_push(skb, TKIP_IV_LEN);
205 memmove(pos, pos + TKIP_IV_LEN, hdrlen);
206 pos += hdrlen;
207
208 /* Increase IV for the frame */
209 spin_lock_irqsave(&key->u.tkip.txlock, flags);
210 key->u.tkip.tx.iv16++;
211 if (key->u.tkip.tx.iv16 == 0)
212 key->u.tkip.tx.iv32++;
213 pos = ieee80211_tkip_add_iv(pos, key);
214 spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
215
216 /* hwaccel - with software IV */
217 if (info->control.hw_key)
218 return 0;
219
220 /* Add room for ICV */
221 skb_put(skb, TKIP_ICV_LEN);
222
223 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
224 key, skb, pos, len);
225 }
226
227
228 ieee80211_tx_result
ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data * tx)229 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
230 {
231 struct sk_buff *skb;
232
233 ieee80211_tx_set_protected(tx);
234
235 skb_queue_walk(&tx->skbs, skb) {
236 if (tkip_encrypt_skb(tx, skb) < 0)
237 return TX_DROP;
238 }
239
240 return TX_CONTINUE;
241 }
242
243
244 ieee80211_rx_result
ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data * rx)245 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
246 {
247 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
248 int hdrlen, res, hwaccel = 0;
249 struct ieee80211_key *key = rx->key;
250 struct sk_buff *skb = rx->skb;
251 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
252
253 hdrlen = ieee80211_hdrlen(hdr->frame_control);
254
255 if (!ieee80211_is_data(hdr->frame_control))
256 return RX_CONTINUE;
257
258 if (!rx->sta || skb->len - hdrlen < 12)
259 return RX_DROP_UNUSABLE;
260
261 /* it may be possible to optimize this a bit more */
262 if (skb_linearize(rx->skb))
263 return RX_DROP_UNUSABLE;
264 hdr = (void *)skb->data;
265
266 /*
267 * Let TKIP code verify IV, but skip decryption.
268 * In the case where hardware checks the IV as well,
269 * we don't even get here, see ieee80211_rx_h_decrypt()
270 */
271 if (status->flag & RX_FLAG_DECRYPTED)
272 hwaccel = 1;
273
274 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
275 key, skb->data + hdrlen,
276 skb->len - hdrlen, rx->sta->sta.addr,
277 hdr->addr1, hwaccel, rx->security_idx,
278 &rx->tkip_iv32,
279 &rx->tkip_iv16);
280 if (res != TKIP_DECRYPT_OK)
281 return RX_DROP_UNUSABLE;
282
283 /* Trim ICV */
284 skb_trim(skb, skb->len - TKIP_ICV_LEN);
285
286 /* Remove IV */
287 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
288 skb_pull(skb, TKIP_IV_LEN);
289
290 return RX_CONTINUE;
291 }
292
293
ccmp_special_blocks(struct sk_buff * skb,u8 * pn,u8 * scratch,int encrypted)294 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
295 int encrypted)
296 {
297 __le16 mask_fc;
298 int a4_included, mgmt;
299 u8 qos_tid;
300 u8 *b_0, *aad;
301 u16 data_len, len_a;
302 unsigned int hdrlen;
303 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
304
305 memset(scratch, 0, 6 * AES_BLOCK_SIZE);
306
307 b_0 = scratch + 3 * AES_BLOCK_SIZE;
308 aad = scratch + 4 * AES_BLOCK_SIZE;
309
310 /*
311 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
312 * Retry, PwrMgt, MoreData; set Protected
313 */
314 mgmt = ieee80211_is_mgmt(hdr->frame_control);
315 mask_fc = hdr->frame_control;
316 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
317 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
318 if (!mgmt)
319 mask_fc &= ~cpu_to_le16(0x0070);
320 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
321
322 hdrlen = ieee80211_hdrlen(hdr->frame_control);
323 len_a = hdrlen - 2;
324 a4_included = ieee80211_has_a4(hdr->frame_control);
325
326 if (ieee80211_is_data_qos(hdr->frame_control))
327 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
328 else
329 qos_tid = 0;
330
331 data_len = skb->len - hdrlen - CCMP_HDR_LEN;
332 if (encrypted)
333 data_len -= CCMP_MIC_LEN;
334
335 /* First block, b_0 */
336 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
337 /* Nonce: Nonce Flags | A2 | PN
338 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
339 */
340 b_0[1] = qos_tid | (mgmt << 4);
341 memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
342 memcpy(&b_0[8], pn, CCMP_PN_LEN);
343 /* l(m) */
344 put_unaligned_be16(data_len, &b_0[14]);
345
346 /* AAD (extra authenticate-only data) / masked 802.11 header
347 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
348 put_unaligned_be16(len_a, &aad[0]);
349 put_unaligned(mask_fc, (__le16 *)&aad[2]);
350 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
351
352 /* Mask Seq#, leave Frag# */
353 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
354 aad[23] = 0;
355
356 if (a4_included) {
357 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
358 aad[30] = qos_tid;
359 aad[31] = 0;
360 } else {
361 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
362 aad[24] = qos_tid;
363 }
364 }
365
366
ccmp_pn2hdr(u8 * hdr,u8 * pn,int key_id)367 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
368 {
369 hdr[0] = pn[5];
370 hdr[1] = pn[4];
371 hdr[2] = 0;
372 hdr[3] = 0x20 | (key_id << 6);
373 hdr[4] = pn[3];
374 hdr[5] = pn[2];
375 hdr[6] = pn[1];
376 hdr[7] = pn[0];
377 }
378
379
ccmp_hdr2pn(u8 * pn,u8 * hdr)380 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
381 {
382 pn[0] = hdr[7];
383 pn[1] = hdr[6];
384 pn[2] = hdr[5];
385 pn[3] = hdr[4];
386 pn[4] = hdr[1];
387 pn[5] = hdr[0];
388 }
389
390
ccmp_encrypt_skb(struct ieee80211_tx_data * tx,struct sk_buff * skb)391 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
392 {
393 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
394 struct ieee80211_key *key = tx->key;
395 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
396 int hdrlen, len, tail;
397 u8 *pos;
398 u8 pn[6];
399 u64 pn64;
400 u8 scratch[6 * AES_BLOCK_SIZE];
401
402 if (info->control.hw_key &&
403 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
404 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
405 /*
406 * hwaccel has no need for preallocated room for CCMP
407 * header or MIC fields
408 */
409 return 0;
410 }
411
412 hdrlen = ieee80211_hdrlen(hdr->frame_control);
413 len = skb->len - hdrlen;
414
415 if (info->control.hw_key)
416 tail = 0;
417 else
418 tail = CCMP_MIC_LEN;
419
420 if (WARN_ON(skb_tailroom(skb) < tail ||
421 skb_headroom(skb) < CCMP_HDR_LEN))
422 return -1;
423
424 pos = skb_push(skb, CCMP_HDR_LEN);
425 memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
426
427 /* the HW only needs room for the IV, but not the actual IV */
428 if (info->control.hw_key &&
429 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
430 return 0;
431
432 hdr = (struct ieee80211_hdr *) pos;
433 pos += hdrlen;
434
435 pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
436
437 pn[5] = pn64;
438 pn[4] = pn64 >> 8;
439 pn[3] = pn64 >> 16;
440 pn[2] = pn64 >> 24;
441 pn[1] = pn64 >> 32;
442 pn[0] = pn64 >> 40;
443
444 ccmp_pn2hdr(pos, pn, key->conf.keyidx);
445
446 /* hwaccel - with software CCMP header */
447 if (info->control.hw_key)
448 return 0;
449
450 pos += CCMP_HDR_LEN;
451 ccmp_special_blocks(skb, pn, scratch, 0);
452 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
453 pos, skb_put(skb, CCMP_MIC_LEN));
454
455 return 0;
456 }
457
458
459 ieee80211_tx_result
ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data * tx)460 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
461 {
462 struct sk_buff *skb;
463
464 ieee80211_tx_set_protected(tx);
465
466 skb_queue_walk(&tx->skbs, skb) {
467 if (ccmp_encrypt_skb(tx, skb) < 0)
468 return TX_DROP;
469 }
470
471 return TX_CONTINUE;
472 }
473
474
475 ieee80211_rx_result
ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data * rx)476 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
477 {
478 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
479 int hdrlen;
480 struct ieee80211_key *key = rx->key;
481 struct sk_buff *skb = rx->skb;
482 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
483 u8 pn[CCMP_PN_LEN];
484 int data_len;
485 int queue;
486
487 hdrlen = ieee80211_hdrlen(hdr->frame_control);
488
489 if (!ieee80211_is_data(hdr->frame_control) &&
490 !ieee80211_is_robust_mgmt_frame(hdr))
491 return RX_CONTINUE;
492
493 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
494 if (!rx->sta || data_len < 0)
495 return RX_DROP_UNUSABLE;
496
497 if (status->flag & RX_FLAG_DECRYPTED) {
498 if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN))
499 return RX_DROP_UNUSABLE;
500 } else {
501 if (skb_linearize(rx->skb))
502 return RX_DROP_UNUSABLE;
503 }
504
505 ccmp_hdr2pn(pn, skb->data + hdrlen);
506
507 queue = rx->security_idx;
508
509 if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
510 key->u.ccmp.replays++;
511 return RX_DROP_UNUSABLE;
512 }
513
514 if (!(status->flag & RX_FLAG_DECRYPTED)) {
515 u8 scratch[6 * AES_BLOCK_SIZE];
516 /* hardware didn't decrypt/verify MIC */
517 ccmp_special_blocks(skb, pn, scratch, 1);
518
519 if (ieee80211_aes_ccm_decrypt(
520 key->u.ccmp.tfm, scratch,
521 skb->data + hdrlen + CCMP_HDR_LEN, data_len,
522 skb->data + skb->len - CCMP_MIC_LEN,
523 skb->data + hdrlen + CCMP_HDR_LEN))
524 return RX_DROP_UNUSABLE;
525 }
526
527 memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
528
529 /* Remove CCMP header and MIC */
530 if (pskb_trim(skb, skb->len - CCMP_MIC_LEN))
531 return RX_DROP_UNUSABLE;
532 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
533 skb_pull(skb, CCMP_HDR_LEN);
534
535 return RX_CONTINUE;
536 }
537
538
bip_aad(struct sk_buff * skb,u8 * aad)539 static void bip_aad(struct sk_buff *skb, u8 *aad)
540 {
541 /* BIP AAD: FC(masked) || A1 || A2 || A3 */
542
543 /* FC type/subtype */
544 aad[0] = skb->data[0];
545 /* Mask FC Retry, PwrMgt, MoreData flags to zero */
546 aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
547 /* A1 || A2 || A3 */
548 memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
549 }
550
551
bip_ipn_set64(u8 * d,u64 pn)552 static inline void bip_ipn_set64(u8 *d, u64 pn)
553 {
554 *d++ = pn;
555 *d++ = pn >> 8;
556 *d++ = pn >> 16;
557 *d++ = pn >> 24;
558 *d++ = pn >> 32;
559 *d = pn >> 40;
560 }
561
bip_ipn_swap(u8 * d,const u8 * s)562 static inline void bip_ipn_swap(u8 *d, const u8 *s)
563 {
564 *d++ = s[5];
565 *d++ = s[4];
566 *d++ = s[3];
567 *d++ = s[2];
568 *d++ = s[1];
569 *d = s[0];
570 }
571
572
573 ieee80211_tx_result
ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data * tx)574 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
575 {
576 struct sk_buff *skb;
577 struct ieee80211_tx_info *info;
578 struct ieee80211_key *key = tx->key;
579 struct ieee80211_mmie *mmie;
580 u8 aad[20];
581 u64 pn64;
582
583 if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
584 return TX_DROP;
585
586 skb = skb_peek(&tx->skbs);
587
588 info = IEEE80211_SKB_CB(skb);
589
590 if (info->control.hw_key)
591 return TX_CONTINUE;
592
593 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
594 return TX_DROP;
595
596 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
597 mmie->element_id = WLAN_EID_MMIE;
598 mmie->length = sizeof(*mmie) - 2;
599 mmie->key_id = cpu_to_le16(key->conf.keyidx);
600
601 /* PN = PN + 1 */
602 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
603
604 bip_ipn_set64(mmie->sequence_number, pn64);
605
606 bip_aad(skb, aad);
607
608 /*
609 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
610 */
611 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
612 skb->data + 24, skb->len - 24, mmie->mic);
613
614 return TX_CONTINUE;
615 }
616
617
618 ieee80211_rx_result
ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data * rx)619 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
620 {
621 struct sk_buff *skb = rx->skb;
622 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
623 struct ieee80211_key *key = rx->key;
624 struct ieee80211_mmie *mmie;
625 u8 aad[20], mic[8], ipn[6];
626 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
627
628 if (!ieee80211_is_mgmt(hdr->frame_control))
629 return RX_CONTINUE;
630
631 /* management frames are already linear */
632
633 if (skb->len < 24 + sizeof(*mmie))
634 return RX_DROP_UNUSABLE;
635
636 mmie = (struct ieee80211_mmie *)
637 (skb->data + skb->len - sizeof(*mmie));
638 if (mmie->element_id != WLAN_EID_MMIE ||
639 mmie->length != sizeof(*mmie) - 2)
640 return RX_DROP_UNUSABLE; /* Invalid MMIE */
641
642 bip_ipn_swap(ipn, mmie->sequence_number);
643
644 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
645 key->u.aes_cmac.replays++;
646 return RX_DROP_UNUSABLE;
647 }
648
649 if (!(status->flag & RX_FLAG_DECRYPTED)) {
650 /* hardware didn't decrypt/verify MIC */
651 bip_aad(skb, aad);
652 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
653 skb->data + 24, skb->len - 24, mic);
654 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
655 key->u.aes_cmac.icverrors++;
656 return RX_DROP_UNUSABLE;
657 }
658 }
659
660 memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
661
662 /* Remove MMIE */
663 skb_trim(skb, skb->len - sizeof(*mmie));
664
665 return RX_CONTINUE;
666 }
667
668 ieee80211_tx_result
ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data * tx)669 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
670 {
671 struct sk_buff *skb;
672 struct ieee80211_tx_info *info = NULL;
673
674 skb_queue_walk(&tx->skbs, skb) {
675 info = IEEE80211_SKB_CB(skb);
676
677 /* handle hw-only algorithm */
678 if (!info->control.hw_key)
679 return TX_DROP;
680 }
681
682 ieee80211_tx_set_protected(tx);
683
684 return TX_CONTINUE;
685 }
686