xref: /linux/net/mac80211/wpa.c (revision 2b8232ce512105e28453f301d1510de8363bccd1)
1 /*
2  * Copyright 2002-2004, Instant802 Networks, Inc.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 #include <linux/netdevice.h>
10 #include <linux/types.h>
11 #include <linux/slab.h>
12 #include <linux/skbuff.h>
13 #include <linux/compiler.h>
14 #include <net/mac80211.h>
15 
16 #include "ieee80211_i.h"
17 #include "michael.h"
18 #include "tkip.h"
19 #include "aes_ccm.h"
20 #include "wpa.h"
21 
22 static int ieee80211_get_hdr_info(const struct sk_buff *skb, u8 **sa, u8 **da,
23 				  u8 *qos_tid, u8 **data, size_t *data_len)
24 {
25 	struct ieee80211_hdr *hdr;
26 	size_t hdrlen;
27 	u16 fc;
28 	int a4_included;
29 	u8 *pos;
30 
31 	hdr = (struct ieee80211_hdr *) skb->data;
32 	fc = le16_to_cpu(hdr->frame_control);
33 
34 	hdrlen = 24;
35 	if ((fc & (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) ==
36 	    (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
37 		hdrlen += ETH_ALEN;
38 		*sa = hdr->addr4;
39 		*da = hdr->addr3;
40 	} else if (fc & IEEE80211_FCTL_FROMDS) {
41 		*sa = hdr->addr3;
42 		*da = hdr->addr1;
43 	} else if (fc & IEEE80211_FCTL_TODS) {
44 		*sa = hdr->addr2;
45 		*da = hdr->addr3;
46 	} else {
47 		*sa = hdr->addr2;
48 		*da = hdr->addr1;
49 	}
50 
51 	if (fc & 0x80)
52 		hdrlen += 2;
53 
54 	*data = skb->data + hdrlen;
55 	*data_len = skb->len - hdrlen;
56 
57 	a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
58 		(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
59 	if ((fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA &&
60 	    fc & IEEE80211_STYPE_QOS_DATA) {
61 		pos = (u8 *) &hdr->addr4;
62 		if (a4_included)
63 			pos += 6;
64 		*qos_tid = pos[0] & 0x0f;
65 		*qos_tid |= 0x80; /* qos_included flag */
66 	} else
67 		*qos_tid = 0;
68 
69 	return skb->len < hdrlen ? -1 : 0;
70 }
71 
72 
73 ieee80211_txrx_result
74 ieee80211_tx_h_michael_mic_add(struct ieee80211_txrx_data *tx)
75 {
76 	u8 *data, *sa, *da, *key, *mic, qos_tid;
77 	size_t data_len;
78 	u16 fc;
79 	struct sk_buff *skb = tx->skb;
80 	int authenticator;
81 	int wpa_test = 0;
82 
83 	fc = tx->fc;
84 
85 	if (!tx->key || tx->key->conf.alg != ALG_TKIP || skb->len < 24 ||
86 	    !WLAN_FC_DATA_PRESENT(fc))
87 		return TXRX_CONTINUE;
88 
89 	if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len))
90 		return TXRX_DROP;
91 
92 	if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
93 	    !(tx->flags & IEEE80211_TXRXD_FRAGMENTED) &&
94 	    !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) &&
95 	    !wpa_test) {
96 		/* hwaccel - with no need for preallocated room for Michael MIC
97 		 */
98 		return TXRX_CONTINUE;
99 	}
100 
101 	if (skb_tailroom(skb) < MICHAEL_MIC_LEN) {
102 		I802_DEBUG_INC(tx->local->tx_expand_skb_head);
103 		if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN,
104 					      MICHAEL_MIC_LEN + TKIP_ICV_LEN,
105 					      GFP_ATOMIC))) {
106 			printk(KERN_DEBUG "%s: failed to allocate more memory "
107 			       "for Michael MIC\n", tx->dev->name);
108 			return TXRX_DROP;
109 		}
110 	}
111 
112 #if 0
113 	authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
114 #else
115 	authenticator = 1;
116 #endif
117 	key = &tx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_TX_MIC_KEY :
118 				 ALG_TKIP_TEMP_AUTH_RX_MIC_KEY];
119 	mic = skb_put(skb, MICHAEL_MIC_LEN);
120 	michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
121 
122 	return TXRX_CONTINUE;
123 }
124 
125 
126 ieee80211_txrx_result
127 ieee80211_rx_h_michael_mic_verify(struct ieee80211_txrx_data *rx)
128 {
129 	u8 *data, *sa, *da, *key = NULL, qos_tid;
130 	size_t data_len;
131 	u16 fc;
132 	u8 mic[MICHAEL_MIC_LEN];
133 	struct sk_buff *skb = rx->skb;
134 	int authenticator = 1, wpa_test = 0;
135 	DECLARE_MAC_BUF(mac);
136 
137 	fc = rx->fc;
138 
139 	/*
140 	 * No way to verify the MIC if the hardware stripped it
141 	 */
142 	if (rx->u.rx.status->flag & RX_FLAG_MMIC_STRIPPED)
143 		return TXRX_CONTINUE;
144 
145 	if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
146 	    !(rx->fc & IEEE80211_FCTL_PROTECTED) || !WLAN_FC_DATA_PRESENT(fc))
147 		return TXRX_CONTINUE;
148 
149 	if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len)
150 	    || data_len < MICHAEL_MIC_LEN)
151 		return TXRX_DROP;
152 
153 	data_len -= MICHAEL_MIC_LEN;
154 
155 #if 0
156 	authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
157 #else
158 	authenticator = 1;
159 #endif
160 	key = &rx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_RX_MIC_KEY :
161 				 ALG_TKIP_TEMP_AUTH_TX_MIC_KEY];
162 	michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
163 	if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
164 		if (!(rx->flags & IEEE80211_TXRXD_RXRA_MATCH))
165 			return TXRX_DROP;
166 
167 		printk(KERN_DEBUG "%s: invalid Michael MIC in data frame from "
168 		       "%s\n", rx->dev->name, print_mac(mac, sa));
169 
170 		mac80211_ev_michael_mic_failure(rx->dev, rx->key->conf.keyidx,
171 						(void *) skb->data);
172 		return TXRX_DROP;
173 	}
174 
175 	/* remove Michael MIC from payload */
176 	skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
177 
178 	/* update IV in key information to be able to detect replays */
179 	rx->key->u.tkip.iv32_rx[rx->u.rx.queue] = rx->u.rx.tkip_iv32;
180 	rx->key->u.tkip.iv16_rx[rx->u.rx.queue] = rx->u.rx.tkip_iv16;
181 
182 	return TXRX_CONTINUE;
183 }
184 
185 
186 static int tkip_encrypt_skb(struct ieee80211_txrx_data *tx,
187 			    struct sk_buff *skb, int test)
188 {
189 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
190 	struct ieee80211_key *key = tx->key;
191 	int hdrlen, len, tailneed;
192 	u16 fc;
193 	u8 *pos;
194 
195 	fc = le16_to_cpu(hdr->frame_control);
196 	hdrlen = ieee80211_get_hdrlen(fc);
197 	len = skb->len - hdrlen;
198 
199 	if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
200 		tailneed = 0;
201 	else
202 		tailneed = TKIP_ICV_LEN;
203 
204 	if ((skb_headroom(skb) < TKIP_IV_LEN ||
205 	     skb_tailroom(skb) < tailneed)) {
206 		I802_DEBUG_INC(tx->local->tx_expand_skb_head);
207 		if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN, tailneed,
208 					      GFP_ATOMIC)))
209 			return -1;
210 	}
211 
212 	pos = skb_push(skb, TKIP_IV_LEN);
213 	memmove(pos, pos + TKIP_IV_LEN, hdrlen);
214 	pos += hdrlen;
215 
216 	/* Increase IV for the frame */
217 	key->u.tkip.iv16++;
218 	if (key->u.tkip.iv16 == 0)
219 		key->u.tkip.iv32++;
220 
221 	if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
222 		hdr = (struct ieee80211_hdr *)skb->data;
223 
224 		/* hwaccel - with preallocated room for IV */
225 		ieee80211_tkip_add_iv(pos, key,
226 				      (u8) (key->u.tkip.iv16 >> 8),
227 				      (u8) (((key->u.tkip.iv16 >> 8) | 0x20) &
228 					    0x7f),
229 				      (u8) key->u.tkip.iv16);
230 
231 		tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
232 		return 0;
233 	}
234 
235 	/* Add room for ICV */
236 	skb_put(skb, TKIP_ICV_LEN);
237 
238 	hdr = (struct ieee80211_hdr *) skb->data;
239 	ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
240 				    key, pos, len, hdr->addr2);
241 	return 0;
242 }
243 
244 
245 ieee80211_txrx_result
246 ieee80211_crypto_tkip_encrypt(struct ieee80211_txrx_data *tx)
247 {
248 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
249 	u16 fc;
250 	struct sk_buff *skb = tx->skb;
251 	int wpa_test = 0, test = 0;
252 
253 	fc = le16_to_cpu(hdr->frame_control);
254 
255 	if (!WLAN_FC_DATA_PRESENT(fc))
256 		return TXRX_CONTINUE;
257 
258 	tx->u.tx.control->icv_len = TKIP_ICV_LEN;
259 	tx->u.tx.control->iv_len = TKIP_IV_LEN;
260 	ieee80211_tx_set_iswep(tx);
261 
262 	if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
263 	    !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
264 	    !wpa_test) {
265 		/* hwaccel - with no need for preallocated room for IV/ICV */
266 		tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
267 		return TXRX_CONTINUE;
268 	}
269 
270 	if (tkip_encrypt_skb(tx, skb, test) < 0)
271 		return TXRX_DROP;
272 
273 	if (tx->u.tx.extra_frag) {
274 		int i;
275 		for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
276 			if (tkip_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
277 			    < 0)
278 				return TXRX_DROP;
279 		}
280 	}
281 
282 	return TXRX_CONTINUE;
283 }
284 
285 
286 ieee80211_txrx_result
287 ieee80211_crypto_tkip_decrypt(struct ieee80211_txrx_data *rx)
288 {
289 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
290 	u16 fc;
291 	int hdrlen, res, hwaccel = 0, wpa_test = 0;
292 	struct ieee80211_key *key = rx->key;
293 	struct sk_buff *skb = rx->skb;
294 	DECLARE_MAC_BUF(mac);
295 
296 	fc = le16_to_cpu(hdr->frame_control);
297 	hdrlen = ieee80211_get_hdrlen(fc);
298 
299 	if ((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
300 		return TXRX_CONTINUE;
301 
302 	if (!rx->sta || skb->len - hdrlen < 12)
303 		return TXRX_DROP;
304 
305 	if (rx->u.rx.status->flag & RX_FLAG_DECRYPTED) {
306 		if (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED) {
307 			/*
308 			 * Hardware took care of all processing, including
309 			 * replay protection, and stripped the ICV/IV so
310 			 * we cannot do any checks here.
311 			 */
312 			return TXRX_CONTINUE;
313 		}
314 
315 		/* let TKIP code verify IV, but skip decryption */
316 		hwaccel = 1;
317 	}
318 
319 	res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
320 					  key, skb->data + hdrlen,
321 					  skb->len - hdrlen, rx->sta->addr,
322 					  hwaccel, rx->u.rx.queue,
323 					  &rx->u.rx.tkip_iv32,
324 					  &rx->u.rx.tkip_iv16);
325 	if (res != TKIP_DECRYPT_OK || wpa_test) {
326 		printk(KERN_DEBUG "%s: TKIP decrypt failed for RX frame from "
327 		       "%s (res=%d)\n",
328 		       rx->dev->name, print_mac(mac, rx->sta->addr), res);
329 		return TXRX_DROP;
330 	}
331 
332 	/* Trim ICV */
333 	skb_trim(skb, skb->len - TKIP_ICV_LEN);
334 
335 	/* Remove IV */
336 	memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
337 	skb_pull(skb, TKIP_IV_LEN);
338 
339 	return TXRX_CONTINUE;
340 }
341 
342 
343 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
344 				int encrypted)
345 {
346 	u16 fc;
347 	int a4_included, qos_included;
348 	u8 qos_tid, *fc_pos, *data, *sa, *da;
349 	int len_a;
350 	size_t data_len;
351 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
352 
353 	fc_pos = (u8 *) &hdr->frame_control;
354 	fc = fc_pos[0] ^ (fc_pos[1] << 8);
355 	a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
356 		(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
357 
358 	ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len);
359 	data_len -= CCMP_HDR_LEN + (encrypted ? CCMP_MIC_LEN : 0);
360 	if (qos_tid & 0x80) {
361 		qos_included = 1;
362 		qos_tid &= 0x0f;
363 	} else
364 		qos_included = 0;
365 	/* First block, b_0 */
366 
367 	b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
368 	/* Nonce: QoS Priority | A2 | PN */
369 	b_0[1] = qos_tid;
370 	memcpy(&b_0[2], hdr->addr2, 6);
371 	memcpy(&b_0[8], pn, CCMP_PN_LEN);
372 	/* l(m) */
373 	b_0[14] = (data_len >> 8) & 0xff;
374 	b_0[15] = data_len & 0xff;
375 
376 
377 	/* AAD (extra authenticate-only data) / masked 802.11 header
378 	 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
379 
380 	len_a = a4_included ? 28 : 22;
381 	if (qos_included)
382 		len_a += 2;
383 
384 	aad[0] = 0; /* (len_a >> 8) & 0xff; */
385 	aad[1] = len_a & 0xff;
386 	/* Mask FC: zero subtype b4 b5 b6 */
387 	aad[2] = fc_pos[0] & ~(BIT(4) | BIT(5) | BIT(6));
388 	/* Retry, PwrMgt, MoreData; set Protected */
389 	aad[3] = (fc_pos[1] & ~(BIT(3) | BIT(4) | BIT(5))) | BIT(6);
390 	memcpy(&aad[4], &hdr->addr1, 18);
391 
392 	/* Mask Seq#, leave Frag# */
393 	aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
394 	aad[23] = 0;
395 	if (a4_included) {
396 		memcpy(&aad[24], hdr->addr4, 6);
397 		aad[30] = 0;
398 		aad[31] = 0;
399 	} else
400 		memset(&aad[24], 0, 8);
401 	if (qos_included) {
402 		u8 *dpos = &aad[a4_included ? 30 : 24];
403 
404 		/* Mask QoS Control field */
405 		dpos[0] = qos_tid;
406 		dpos[1] = 0;
407 	}
408 }
409 
410 
411 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
412 {
413 	hdr[0] = pn[5];
414 	hdr[1] = pn[4];
415 	hdr[2] = 0;
416 	hdr[3] = 0x20 | (key_id << 6);
417 	hdr[4] = pn[3];
418 	hdr[5] = pn[2];
419 	hdr[6] = pn[1];
420 	hdr[7] = pn[0];
421 }
422 
423 
424 static inline int ccmp_hdr2pn(u8 *pn, u8 *hdr)
425 {
426 	pn[0] = hdr[7];
427 	pn[1] = hdr[6];
428 	pn[2] = hdr[5];
429 	pn[3] = hdr[4];
430 	pn[4] = hdr[1];
431 	pn[5] = hdr[0];
432 	return (hdr[3] >> 6) & 0x03;
433 }
434 
435 
436 static int ccmp_encrypt_skb(struct ieee80211_txrx_data *tx,
437 			    struct sk_buff *skb, int test)
438 {
439 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
440 	struct ieee80211_key *key = tx->key;
441 	int hdrlen, len, tailneed;
442 	u16 fc;
443 	u8 *pos, *pn, *b_0, *aad, *scratch;
444 	int i;
445 
446 	scratch = key->u.ccmp.tx_crypto_buf;
447 	b_0 = scratch + 3 * AES_BLOCK_LEN;
448 	aad = scratch + 4 * AES_BLOCK_LEN;
449 
450 	fc = le16_to_cpu(hdr->frame_control);
451 	hdrlen = ieee80211_get_hdrlen(fc);
452 	len = skb->len - hdrlen;
453 
454 	if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
455 		tailneed = 0;
456 	else
457 		tailneed = CCMP_MIC_LEN;
458 
459 	if ((skb_headroom(skb) < CCMP_HDR_LEN ||
460 	     skb_tailroom(skb) < tailneed)) {
461 		I802_DEBUG_INC(tx->local->tx_expand_skb_head);
462 		if (unlikely(pskb_expand_head(skb, CCMP_HDR_LEN, tailneed,
463 					      GFP_ATOMIC)))
464 			return -1;
465 	}
466 
467 	pos = skb_push(skb, CCMP_HDR_LEN);
468 	memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
469 	hdr = (struct ieee80211_hdr *) pos;
470 	pos += hdrlen;
471 
472 	/* PN = PN + 1 */
473 	pn = key->u.ccmp.tx_pn;
474 
475 	for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
476 		pn[i]++;
477 		if (pn[i])
478 			break;
479 	}
480 
481 	ccmp_pn2hdr(pos, pn, key->conf.keyidx);
482 
483 	if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
484 		/* hwaccel - with preallocated room for CCMP header */
485 		tx->u.tx.control->key_idx = key->conf.hw_key_idx;
486 		return 0;
487 	}
488 
489 	pos += CCMP_HDR_LEN;
490 	ccmp_special_blocks(skb, pn, b_0, aad, 0);
491 	ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, b_0, aad, pos, len,
492 				  pos, skb_put(skb, CCMP_MIC_LEN));
493 
494 	return 0;
495 }
496 
497 
498 ieee80211_txrx_result
499 ieee80211_crypto_ccmp_encrypt(struct ieee80211_txrx_data *tx)
500 {
501 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
502 	u16 fc;
503 	struct sk_buff *skb = tx->skb;
504 	int test = 0;
505 
506 	fc = le16_to_cpu(hdr->frame_control);
507 
508 	if (!WLAN_FC_DATA_PRESENT(fc))
509 		return TXRX_CONTINUE;
510 
511 	tx->u.tx.control->icv_len = CCMP_MIC_LEN;
512 	tx->u.tx.control->iv_len = CCMP_HDR_LEN;
513 	ieee80211_tx_set_iswep(tx);
514 
515 	if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
516 	    !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
517 		/* hwaccel - with no need for preallocated room for CCMP "
518 		 * header or MIC fields */
519 		tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
520 		return TXRX_CONTINUE;
521 	}
522 
523 	if (ccmp_encrypt_skb(tx, skb, test) < 0)
524 		return TXRX_DROP;
525 
526 	if (tx->u.tx.extra_frag) {
527 		int i;
528 		for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
529 			if (ccmp_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
530 			    < 0)
531 				return TXRX_DROP;
532 		}
533 	}
534 
535 	return TXRX_CONTINUE;
536 }
537 
538 
539 ieee80211_txrx_result
540 ieee80211_crypto_ccmp_decrypt(struct ieee80211_txrx_data *rx)
541 {
542 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
543 	u16 fc;
544 	int hdrlen;
545 	struct ieee80211_key *key = rx->key;
546 	struct sk_buff *skb = rx->skb;
547 	u8 pn[CCMP_PN_LEN];
548 	int data_len;
549 	DECLARE_MAC_BUF(mac);
550 
551 	fc = le16_to_cpu(hdr->frame_control);
552 	hdrlen = ieee80211_get_hdrlen(fc);
553 
554 	if ((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
555 		return TXRX_CONTINUE;
556 
557 	data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
558 	if (!rx->sta || data_len < 0)
559 		return TXRX_DROP;
560 
561 	if ((rx->u.rx.status->flag & RX_FLAG_DECRYPTED) &&
562 	    (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED))
563 		return TXRX_CONTINUE;
564 
565 	(void) ccmp_hdr2pn(pn, skb->data + hdrlen);
566 
567 	if (memcmp(pn, key->u.ccmp.rx_pn[rx->u.rx.queue], CCMP_PN_LEN) <= 0) {
568 #ifdef CONFIG_MAC80211_DEBUG
569 		u8 *ppn = key->u.ccmp.rx_pn[rx->u.rx.queue];
570 
571 		printk(KERN_DEBUG "%s: CCMP replay detected for RX frame from "
572 		       "%s (RX PN %02x%02x%02x%02x%02x%02x <= prev. PN "
573 		       "%02x%02x%02x%02x%02x%02x)\n", rx->dev->name,
574 		       print_mac(mac, rx->sta->addr),
575 		       pn[0], pn[1], pn[2], pn[3], pn[4], pn[5],
576 		       ppn[0], ppn[1], ppn[2], ppn[3], ppn[4], ppn[5]);
577 #endif /* CONFIG_MAC80211_DEBUG */
578 		key->u.ccmp.replays++;
579 		return TXRX_DROP;
580 	}
581 
582 	if (!(rx->u.rx.status->flag & RX_FLAG_DECRYPTED)) {
583 		/* hardware didn't decrypt/verify MIC */
584 		u8 *scratch, *b_0, *aad;
585 
586 		scratch = key->u.ccmp.rx_crypto_buf;
587 		b_0 = scratch + 3 * AES_BLOCK_LEN;
588 		aad = scratch + 4 * AES_BLOCK_LEN;
589 
590 		ccmp_special_blocks(skb, pn, b_0, aad, 1);
591 
592 		if (ieee80211_aes_ccm_decrypt(
593 			    key->u.ccmp.tfm, scratch, b_0, aad,
594 			    skb->data + hdrlen + CCMP_HDR_LEN, data_len,
595 			    skb->data + skb->len - CCMP_MIC_LEN,
596 			    skb->data + hdrlen + CCMP_HDR_LEN)) {
597 			printk(KERN_DEBUG "%s: CCMP decrypt failed for RX "
598 			       "frame from %s\n", rx->dev->name,
599 			       print_mac(mac, rx->sta->addr));
600 			return TXRX_DROP;
601 		}
602 	}
603 
604 	memcpy(key->u.ccmp.rx_pn[rx->u.rx.queue], pn, CCMP_PN_LEN);
605 
606 	/* Remove CCMP header and MIC */
607 	skb_trim(skb, skb->len - CCMP_MIC_LEN);
608 	memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
609 	skb_pull(skb, CCMP_HDR_LEN);
610 
611 	return TXRX_CONTINUE;
612 }
613