xref: /openbmc/linux/net/mac80211/wpa.c (revision ee8a99bd)
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
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 += IEEE80211_TKIP_ICV_LEN;
66 
67 	if (WARN_ON(skb_tailroom(skb) < tail ||
68 		    skb_headroom(skb) < IEEE80211_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
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_no_key;
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 	rx->key->u.tkip.mic_failures++;
165 
166 mic_fail_no_key:
167 	/*
168 	 * In some cases the key can be unset - e.g. a multicast packet, in
169 	 * a driver that supports HW encryption. Send up the key idx only if
170 	 * the key is set.
171 	 */
172 	mac80211_ev_michael_mic_failure(rx->sdata,
173 					rx->key ? rx->key->conf.keyidx : -1,
174 					(void *) skb->data, NULL, GFP_ATOMIC);
175 	return RX_DROP_UNUSABLE;
176 }
177 
178 
179 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
180 {
181 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
182 	struct ieee80211_key *key = tx->key;
183 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
184 	unsigned int hdrlen;
185 	int len, tail;
186 	u8 *pos;
187 
188 	if (info->control.hw_key &&
189 	    !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
190 	    !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
191 		/* hwaccel - with no need for software-generated IV */
192 		return 0;
193 	}
194 
195 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
196 	len = skb->len - hdrlen;
197 
198 	if (info->control.hw_key)
199 		tail = 0;
200 	else
201 		tail = IEEE80211_TKIP_ICV_LEN;
202 
203 	if (WARN_ON(skb_tailroom(skb) < tail ||
204 		    skb_headroom(skb) < IEEE80211_TKIP_IV_LEN))
205 		return -1;
206 
207 	pos = skb_push(skb, IEEE80211_TKIP_IV_LEN);
208 	memmove(pos, pos + IEEE80211_TKIP_IV_LEN, hdrlen);
209 	skb_set_network_header(skb, skb_network_offset(skb) +
210 				    IEEE80211_TKIP_IV_LEN);
211 	pos += hdrlen;
212 
213 	/* the HW only needs room for the IV, but not the actual IV */
214 	if (info->control.hw_key &&
215 	    (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
216 		return 0;
217 
218 	/* Increase IV for the frame */
219 	spin_lock(&key->u.tkip.txlock);
220 	key->u.tkip.tx.iv16++;
221 	if (key->u.tkip.tx.iv16 == 0)
222 		key->u.tkip.tx.iv32++;
223 	pos = ieee80211_tkip_add_iv(pos, key);
224 	spin_unlock(&key->u.tkip.txlock);
225 
226 	/* hwaccel - with software IV */
227 	if (info->control.hw_key)
228 		return 0;
229 
230 	/* Add room for ICV */
231 	skb_put(skb, IEEE80211_TKIP_ICV_LEN);
232 
233 	return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
234 					   key, skb, pos, len);
235 }
236 
237 
238 ieee80211_tx_result
239 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
240 {
241 	struct sk_buff *skb;
242 
243 	ieee80211_tx_set_protected(tx);
244 
245 	skb_queue_walk(&tx->skbs, skb) {
246 		if (tkip_encrypt_skb(tx, skb) < 0)
247 			return TX_DROP;
248 	}
249 
250 	return TX_CONTINUE;
251 }
252 
253 
254 ieee80211_rx_result
255 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
256 {
257 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
258 	int hdrlen, res, hwaccel = 0;
259 	struct ieee80211_key *key = rx->key;
260 	struct sk_buff *skb = rx->skb;
261 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
262 
263 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
264 
265 	if (!ieee80211_is_data(hdr->frame_control))
266 		return RX_CONTINUE;
267 
268 	if (!rx->sta || skb->len - hdrlen < 12)
269 		return RX_DROP_UNUSABLE;
270 
271 	/* it may be possible to optimize this a bit more */
272 	if (skb_linearize(rx->skb))
273 		return RX_DROP_UNUSABLE;
274 	hdr = (void *)skb->data;
275 
276 	/*
277 	 * Let TKIP code verify IV, but skip decryption.
278 	 * In the case where hardware checks the IV as well,
279 	 * we don't even get here, see ieee80211_rx_h_decrypt()
280 	 */
281 	if (status->flag & RX_FLAG_DECRYPTED)
282 		hwaccel = 1;
283 
284 	res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
285 					  key, skb->data + hdrlen,
286 					  skb->len - hdrlen, rx->sta->sta.addr,
287 					  hdr->addr1, hwaccel, rx->security_idx,
288 					  &rx->tkip_iv32,
289 					  &rx->tkip_iv16);
290 	if (res != TKIP_DECRYPT_OK)
291 		return RX_DROP_UNUSABLE;
292 
293 	/* Trim ICV */
294 	skb_trim(skb, skb->len - IEEE80211_TKIP_ICV_LEN);
295 
296 	/* Remove IV */
297 	memmove(skb->data + IEEE80211_TKIP_IV_LEN, skb->data, hdrlen);
298 	skb_pull(skb, IEEE80211_TKIP_IV_LEN);
299 
300 	return RX_CONTINUE;
301 }
302 
303 
304 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
305 				int encrypted)
306 {
307 	__le16 mask_fc;
308 	int a4_included, mgmt;
309 	u8 qos_tid;
310 	u8 *b_0, *aad;
311 	u16 data_len, len_a;
312 	unsigned int hdrlen;
313 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
314 
315 	memset(scratch, 0, 6 * AES_BLOCK_SIZE);
316 
317 	b_0 = scratch + 3 * AES_BLOCK_SIZE;
318 	aad = scratch + 4 * AES_BLOCK_SIZE;
319 
320 	/*
321 	 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
322 	 * Retry, PwrMgt, MoreData; set Protected
323 	 */
324 	mgmt = ieee80211_is_mgmt(hdr->frame_control);
325 	mask_fc = hdr->frame_control;
326 	mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
327 				IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
328 	if (!mgmt)
329 		mask_fc &= ~cpu_to_le16(0x0070);
330 	mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
331 
332 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
333 	len_a = hdrlen - 2;
334 	a4_included = ieee80211_has_a4(hdr->frame_control);
335 
336 	if (ieee80211_is_data_qos(hdr->frame_control))
337 		qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
338 	else
339 		qos_tid = 0;
340 
341 	data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN;
342 	if (encrypted)
343 		data_len -= IEEE80211_CCMP_MIC_LEN;
344 
345 	/* First block, b_0 */
346 	b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
347 	/* Nonce: Nonce Flags | A2 | PN
348 	 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
349 	 */
350 	b_0[1] = qos_tid | (mgmt << 4);
351 	memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
352 	memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN);
353 	/* l(m) */
354 	put_unaligned_be16(data_len, &b_0[14]);
355 
356 	/* AAD (extra authenticate-only data) / masked 802.11 header
357 	 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
358 	put_unaligned_be16(len_a, &aad[0]);
359 	put_unaligned(mask_fc, (__le16 *)&aad[2]);
360 	memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
361 
362 	/* Mask Seq#, leave Frag# */
363 	aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
364 	aad[23] = 0;
365 
366 	if (a4_included) {
367 		memcpy(&aad[24], hdr->addr4, ETH_ALEN);
368 		aad[30] = qos_tid;
369 		aad[31] = 0;
370 	} else {
371 		memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
372 		aad[24] = qos_tid;
373 	}
374 }
375 
376 
377 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
378 {
379 	hdr[0] = pn[5];
380 	hdr[1] = pn[4];
381 	hdr[2] = 0;
382 	hdr[3] = 0x20 | (key_id << 6);
383 	hdr[4] = pn[3];
384 	hdr[5] = pn[2];
385 	hdr[6] = pn[1];
386 	hdr[7] = pn[0];
387 }
388 
389 
390 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
391 {
392 	pn[0] = hdr[7];
393 	pn[1] = hdr[6];
394 	pn[2] = hdr[5];
395 	pn[3] = hdr[4];
396 	pn[4] = hdr[1];
397 	pn[5] = hdr[0];
398 }
399 
400 
401 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
402 {
403 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
404 	struct ieee80211_key *key = tx->key;
405 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
406 	int hdrlen, len, tail;
407 	u8 *pos;
408 	u8 pn[6];
409 	u64 pn64;
410 	u8 scratch[6 * AES_BLOCK_SIZE];
411 
412 	if (info->control.hw_key &&
413 	    !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
414 	    !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
415 		/*
416 		 * hwaccel has no need for preallocated room for CCMP
417 		 * header or MIC fields
418 		 */
419 		return 0;
420 	}
421 
422 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
423 	len = skb->len - hdrlen;
424 
425 	if (info->control.hw_key)
426 		tail = 0;
427 	else
428 		tail = IEEE80211_CCMP_MIC_LEN;
429 
430 	if (WARN_ON(skb_tailroom(skb) < tail ||
431 		    skb_headroom(skb) < IEEE80211_CCMP_HDR_LEN))
432 		return -1;
433 
434 	pos = skb_push(skb, IEEE80211_CCMP_HDR_LEN);
435 	memmove(pos, pos + IEEE80211_CCMP_HDR_LEN, hdrlen);
436 	skb_set_network_header(skb, skb_network_offset(skb) +
437 				    IEEE80211_CCMP_HDR_LEN);
438 
439 	/* the HW only needs room for the IV, but not the actual IV */
440 	if (info->control.hw_key &&
441 	    (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
442 		return 0;
443 
444 	hdr = (struct ieee80211_hdr *) pos;
445 	pos += hdrlen;
446 
447 	pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
448 
449 	pn[5] = pn64;
450 	pn[4] = pn64 >> 8;
451 	pn[3] = pn64 >> 16;
452 	pn[2] = pn64 >> 24;
453 	pn[1] = pn64 >> 32;
454 	pn[0] = pn64 >> 40;
455 
456 	ccmp_pn2hdr(pos, pn, key->conf.keyidx);
457 
458 	/* hwaccel - with software CCMP header */
459 	if (info->control.hw_key)
460 		return 0;
461 
462 	pos += IEEE80211_CCMP_HDR_LEN;
463 	ccmp_special_blocks(skb, pn, scratch, 0);
464 	ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
465 				  pos, skb_put(skb, IEEE80211_CCMP_MIC_LEN));
466 
467 	return 0;
468 }
469 
470 
471 ieee80211_tx_result
472 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
473 {
474 	struct sk_buff *skb;
475 
476 	ieee80211_tx_set_protected(tx);
477 
478 	skb_queue_walk(&tx->skbs, skb) {
479 		if (ccmp_encrypt_skb(tx, skb) < 0)
480 			return TX_DROP;
481 	}
482 
483 	return TX_CONTINUE;
484 }
485 
486 
487 ieee80211_rx_result
488 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
489 {
490 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
491 	int hdrlen;
492 	struct ieee80211_key *key = rx->key;
493 	struct sk_buff *skb = rx->skb;
494 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
495 	u8 pn[IEEE80211_CCMP_PN_LEN];
496 	int data_len;
497 	int queue;
498 
499 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
500 
501 	if (!ieee80211_is_data(hdr->frame_control) &&
502 	    !ieee80211_is_robust_mgmt_frame(hdr))
503 		return RX_CONTINUE;
504 
505 	data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN -
506 		   IEEE80211_CCMP_MIC_LEN;
507 	if (!rx->sta || data_len < 0)
508 		return RX_DROP_UNUSABLE;
509 
510 	if (status->flag & RX_FLAG_DECRYPTED) {
511 		if (!pskb_may_pull(rx->skb, hdrlen + IEEE80211_CCMP_HDR_LEN))
512 			return RX_DROP_UNUSABLE;
513 	} else {
514 		if (skb_linearize(rx->skb))
515 			return RX_DROP_UNUSABLE;
516 	}
517 
518 	ccmp_hdr2pn(pn, skb->data + hdrlen);
519 
520 	queue = rx->security_idx;
521 
522 	if (memcmp(pn, key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN) <= 0) {
523 		key->u.ccmp.replays++;
524 		return RX_DROP_UNUSABLE;
525 	}
526 
527 	if (!(status->flag & RX_FLAG_DECRYPTED)) {
528 		u8 scratch[6 * AES_BLOCK_SIZE];
529 		/* hardware didn't decrypt/verify MIC */
530 		ccmp_special_blocks(skb, pn, scratch, 1);
531 
532 		if (ieee80211_aes_ccm_decrypt(
533 			    key->u.ccmp.tfm, scratch,
534 			    skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
535 			    data_len,
536 			    skb->data + skb->len - IEEE80211_CCMP_MIC_LEN,
537 			    skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN))
538 			return RX_DROP_UNUSABLE;
539 	}
540 
541 	memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
542 
543 	/* Remove CCMP header and MIC */
544 	if (pskb_trim(skb, skb->len - IEEE80211_CCMP_MIC_LEN))
545 		return RX_DROP_UNUSABLE;
546 	memmove(skb->data + IEEE80211_CCMP_HDR_LEN, skb->data, hdrlen);
547 	skb_pull(skb, IEEE80211_CCMP_HDR_LEN);
548 
549 	return RX_CONTINUE;
550 }
551 
552 
553 static void bip_aad(struct sk_buff *skb, u8 *aad)
554 {
555 	__le16 mask_fc;
556 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
557 
558 	/* BIP AAD: FC(masked) || A1 || A2 || A3 */
559 
560 	/* FC type/subtype */
561 	/* Mask FC Retry, PwrMgt, MoreData flags to zero */
562 	mask_fc = hdr->frame_control;
563 	mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY | IEEE80211_FCTL_PM |
564 				IEEE80211_FCTL_MOREDATA);
565 	put_unaligned(mask_fc, (__le16 *) &aad[0]);
566 	/* A1 || A2 || A3 */
567 	memcpy(aad + 2, &hdr->addr1, 3 * ETH_ALEN);
568 }
569 
570 
571 static inline void bip_ipn_set64(u8 *d, u64 pn)
572 {
573 	*d++ = pn;
574 	*d++ = pn >> 8;
575 	*d++ = pn >> 16;
576 	*d++ = pn >> 24;
577 	*d++ = pn >> 32;
578 	*d = pn >> 40;
579 }
580 
581 static inline void bip_ipn_swap(u8 *d, const u8 *s)
582 {
583 	*d++ = s[5];
584 	*d++ = s[4];
585 	*d++ = s[3];
586 	*d++ = s[2];
587 	*d++ = s[1];
588 	*d = s[0];
589 }
590 
591 
592 ieee80211_tx_result
593 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
594 {
595 	struct sk_buff *skb;
596 	struct ieee80211_tx_info *info;
597 	struct ieee80211_key *key = tx->key;
598 	struct ieee80211_mmie *mmie;
599 	u8 aad[20];
600 	u64 pn64;
601 
602 	if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
603 		return TX_DROP;
604 
605 	skb = skb_peek(&tx->skbs);
606 
607 	info = IEEE80211_SKB_CB(skb);
608 
609 	if (info->control.hw_key)
610 		return TX_CONTINUE;
611 
612 	if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
613 		return TX_DROP;
614 
615 	mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
616 	mmie->element_id = WLAN_EID_MMIE;
617 	mmie->length = sizeof(*mmie) - 2;
618 	mmie->key_id = cpu_to_le16(key->conf.keyidx);
619 
620 	/* PN = PN + 1 */
621 	pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
622 
623 	bip_ipn_set64(mmie->sequence_number, pn64);
624 
625 	bip_aad(skb, aad);
626 
627 	/*
628 	 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
629 	 */
630 	ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
631 			   skb->data + 24, skb->len - 24, mmie->mic);
632 
633 	return TX_CONTINUE;
634 }
635 
636 
637 ieee80211_rx_result
638 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
639 {
640 	struct sk_buff *skb = rx->skb;
641 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
642 	struct ieee80211_key *key = rx->key;
643 	struct ieee80211_mmie *mmie;
644 	u8 aad[20], mic[8], ipn[6];
645 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
646 
647 	if (!ieee80211_is_mgmt(hdr->frame_control))
648 		return RX_CONTINUE;
649 
650 	/* management frames are already linear */
651 
652 	if (skb->len < 24 + sizeof(*mmie))
653 		return RX_DROP_UNUSABLE;
654 
655 	mmie = (struct ieee80211_mmie *)
656 		(skb->data + skb->len - sizeof(*mmie));
657 	if (mmie->element_id != WLAN_EID_MMIE ||
658 	    mmie->length != sizeof(*mmie) - 2)
659 		return RX_DROP_UNUSABLE; /* Invalid MMIE */
660 
661 	bip_ipn_swap(ipn, mmie->sequence_number);
662 
663 	if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
664 		key->u.aes_cmac.replays++;
665 		return RX_DROP_UNUSABLE;
666 	}
667 
668 	if (!(status->flag & RX_FLAG_DECRYPTED)) {
669 		/* hardware didn't decrypt/verify MIC */
670 		bip_aad(skb, aad);
671 		ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
672 				   skb->data + 24, skb->len - 24, mic);
673 		if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
674 			key->u.aes_cmac.icverrors++;
675 			return RX_DROP_UNUSABLE;
676 		}
677 	}
678 
679 	memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
680 
681 	/* Remove MMIE */
682 	skb_trim(skb, skb->len - sizeof(*mmie));
683 
684 	return RX_CONTINUE;
685 }
686 
687 ieee80211_tx_result
688 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
689 {
690 	struct sk_buff *skb;
691 	struct ieee80211_tx_info *info = NULL;
692 
693 	skb_queue_walk(&tx->skbs, skb) {
694 		info  = IEEE80211_SKB_CB(skb);
695 
696 		/* handle hw-only algorithm */
697 		if (!info->control.hw_key)
698 			return TX_DROP;
699 	}
700 
701 	ieee80211_tx_set_protected(tx);
702 
703 	return TX_CONTINUE;
704 }
705