xref: /openbmc/linux/net/mac80211/wpa.c (revision 4800cd83)
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 
19 #include "ieee80211_i.h"
20 #include "michael.h"
21 #include "tkip.h"
22 #include "aes_ccm.h"
23 #include "aes_cmac.h"
24 #include "wpa.h"
25 
26 ieee80211_tx_result
27 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
28 {
29 	u8 *data, *key, *mic, key_offset;
30 	size_t data_len;
31 	unsigned int hdrlen;
32 	struct ieee80211_hdr *hdr;
33 	struct sk_buff *skb = tx->skb;
34 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
35 	int authenticator;
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 (info->control.hw_key &&
51 	    !(tx->flags & IEEE80211_TX_FRAGMENTED) &&
52 	    !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
53 		/* hwaccel - with no need for SW-generated MMIC */
54 		return TX_CONTINUE;
55 	}
56 
57 	tail = MICHAEL_MIC_LEN;
58 	if (!info->control.hw_key)
59 		tail += TKIP_ICV_LEN;
60 
61 	if (WARN_ON(skb_tailroom(skb) < tail ||
62 		    skb_headroom(skb) < TKIP_IV_LEN))
63 		return TX_DROP;
64 
65 #if 0
66 	authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
67 #else
68 	authenticator = 1;
69 #endif
70 	key_offset = authenticator ?
71 		NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY :
72 		NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY;
73 	key = &tx->key->conf.key[key_offset];
74 	mic = skb_put(skb, MICHAEL_MIC_LEN);
75 	michael_mic(key, hdr, data, data_len, mic);
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, key_offset;
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 	int authenticator = 1, wpa_test = 0;
92 
93 	/* No way to verify the MIC if the hardware stripped it */
94 	if (status->flag & RX_FLAG_MMIC_STRIPPED)
95 		return RX_CONTINUE;
96 
97 	if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
98 	    !ieee80211_has_protected(hdr->frame_control) ||
99 	    !ieee80211_is_data_present(hdr->frame_control))
100 		return RX_CONTINUE;
101 
102 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
103 	if (skb->len < hdrlen + MICHAEL_MIC_LEN)
104 		return RX_DROP_UNUSABLE;
105 
106 	data = skb->data + hdrlen;
107 	data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
108 
109 #if 0
110 	authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
111 #else
112 	authenticator = 1;
113 #endif
114 	key_offset = authenticator ?
115 		NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY :
116 		NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY;
117 	key = &rx->key->conf.key[key_offset];
118 	michael_mic(key, hdr, data, data_len, mic);
119 	if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
120 		if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
121 			return RX_DROP_UNUSABLE;
122 
123 		mac80211_ev_michael_mic_failure(rx->sdata, rx->key->conf.keyidx,
124 						(void *) skb->data, NULL,
125 						GFP_ATOMIC);
126 		return RX_DROP_UNUSABLE;
127 	}
128 
129 	/* remove Michael MIC from payload */
130 	skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
131 
132 	/* update IV in key information to be able to detect replays */
133 	rx->key->u.tkip.rx[rx->queue].iv32 = rx->tkip_iv32;
134 	rx->key->u.tkip.rx[rx->queue].iv16 = rx->tkip_iv16;
135 
136 	return RX_CONTINUE;
137 }
138 
139 
140 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
141 {
142 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
143 	struct ieee80211_key *key = tx->key;
144 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
145 	unsigned int hdrlen;
146 	int len, tail;
147 	u8 *pos;
148 
149 	if (info->control.hw_key &&
150 	    !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
151 		/* hwaccel - with no need for software-generated IV */
152 		return 0;
153 	}
154 
155 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
156 	len = skb->len - hdrlen;
157 
158 	if (info->control.hw_key)
159 		tail = 0;
160 	else
161 		tail = TKIP_ICV_LEN;
162 
163 	if (WARN_ON(skb_tailroom(skb) < tail ||
164 		    skb_headroom(skb) < TKIP_IV_LEN))
165 		return -1;
166 
167 	pos = skb_push(skb, TKIP_IV_LEN);
168 	memmove(pos, pos + TKIP_IV_LEN, hdrlen);
169 	pos += hdrlen;
170 
171 	/* Increase IV for the frame */
172 	key->u.tkip.tx.iv16++;
173 	if (key->u.tkip.tx.iv16 == 0)
174 		key->u.tkip.tx.iv32++;
175 
176 	pos = ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16);
177 
178 	/* hwaccel - with software IV */
179 	if (info->control.hw_key)
180 		return 0;
181 
182 	/* Add room for ICV */
183 	skb_put(skb, TKIP_ICV_LEN);
184 
185 	hdr = (struct ieee80211_hdr *) skb->data;
186 	return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
187 					   key, pos, len, hdr->addr2);
188 }
189 
190 
191 ieee80211_tx_result
192 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
193 {
194 	struct sk_buff *skb = tx->skb;
195 
196 	ieee80211_tx_set_protected(tx);
197 
198 	do {
199 		if (tkip_encrypt_skb(tx, skb) < 0)
200 			return TX_DROP;
201 	} while ((skb = skb->next));
202 
203 	return TX_CONTINUE;
204 }
205 
206 
207 ieee80211_rx_result
208 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
209 {
210 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
211 	int hdrlen, res, hwaccel = 0, wpa_test = 0;
212 	struct ieee80211_key *key = rx->key;
213 	struct sk_buff *skb = rx->skb;
214 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
215 
216 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
217 
218 	if (!ieee80211_is_data(hdr->frame_control))
219 		return RX_CONTINUE;
220 
221 	if (!rx->sta || skb->len - hdrlen < 12)
222 		return RX_DROP_UNUSABLE;
223 
224 	/*
225 	 * Let TKIP code verify IV, but skip decryption.
226 	 * In the case where hardware checks the IV as well,
227 	 * we don't even get here, see ieee80211_rx_h_decrypt()
228 	 */
229 	if (status->flag & RX_FLAG_DECRYPTED)
230 		hwaccel = 1;
231 
232 	res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
233 					  key, skb->data + hdrlen,
234 					  skb->len - hdrlen, rx->sta->sta.addr,
235 					  hdr->addr1, hwaccel, rx->queue,
236 					  &rx->tkip_iv32,
237 					  &rx->tkip_iv16);
238 	if (res != TKIP_DECRYPT_OK || wpa_test)
239 		return RX_DROP_UNUSABLE;
240 
241 	/* Trim ICV */
242 	skb_trim(skb, skb->len - TKIP_ICV_LEN);
243 
244 	/* Remove IV */
245 	memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
246 	skb_pull(skb, TKIP_IV_LEN);
247 
248 	return RX_CONTINUE;
249 }
250 
251 
252 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
253 				int encrypted)
254 {
255 	__le16 mask_fc;
256 	int a4_included, mgmt;
257 	u8 qos_tid;
258 	u8 *b_0, *aad;
259 	u16 data_len, len_a;
260 	unsigned int hdrlen;
261 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
262 
263 	b_0 = scratch + 3 * AES_BLOCK_LEN;
264 	aad = scratch + 4 * AES_BLOCK_LEN;
265 
266 	/*
267 	 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
268 	 * Retry, PwrMgt, MoreData; set Protected
269 	 */
270 	mgmt = ieee80211_is_mgmt(hdr->frame_control);
271 	mask_fc = hdr->frame_control;
272 	mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
273 				IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
274 	if (!mgmt)
275 		mask_fc &= ~cpu_to_le16(0x0070);
276 	mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
277 
278 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
279 	len_a = hdrlen - 2;
280 	a4_included = ieee80211_has_a4(hdr->frame_control);
281 
282 	if (ieee80211_is_data_qos(hdr->frame_control))
283 		qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
284 	else
285 		qos_tid = 0;
286 
287 	data_len = skb->len - hdrlen - CCMP_HDR_LEN;
288 	if (encrypted)
289 		data_len -= CCMP_MIC_LEN;
290 
291 	/* First block, b_0 */
292 	b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
293 	/* Nonce: Nonce Flags | A2 | PN
294 	 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
295 	 */
296 	b_0[1] = qos_tid | (mgmt << 4);
297 	memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
298 	memcpy(&b_0[8], pn, CCMP_PN_LEN);
299 	/* l(m) */
300 	put_unaligned_be16(data_len, &b_0[14]);
301 
302 	/* AAD (extra authenticate-only data) / masked 802.11 header
303 	 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
304 	put_unaligned_be16(len_a, &aad[0]);
305 	put_unaligned(mask_fc, (__le16 *)&aad[2]);
306 	memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
307 
308 	/* Mask Seq#, leave Frag# */
309 	aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
310 	aad[23] = 0;
311 
312 	if (a4_included) {
313 		memcpy(&aad[24], hdr->addr4, ETH_ALEN);
314 		aad[30] = qos_tid;
315 		aad[31] = 0;
316 	} else {
317 		memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
318 		aad[24] = qos_tid;
319 	}
320 }
321 
322 
323 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
324 {
325 	hdr[0] = pn[5];
326 	hdr[1] = pn[4];
327 	hdr[2] = 0;
328 	hdr[3] = 0x20 | (key_id << 6);
329 	hdr[4] = pn[3];
330 	hdr[5] = pn[2];
331 	hdr[6] = pn[1];
332 	hdr[7] = pn[0];
333 }
334 
335 
336 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
337 {
338 	pn[0] = hdr[7];
339 	pn[1] = hdr[6];
340 	pn[2] = hdr[5];
341 	pn[3] = hdr[4];
342 	pn[4] = hdr[1];
343 	pn[5] = hdr[0];
344 }
345 
346 
347 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
348 {
349 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
350 	struct ieee80211_key *key = tx->key;
351 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
352 	int hdrlen, len, tail;
353 	u8 *pos, *pn;
354 	int i;
355 
356 	if (info->control.hw_key &&
357 	    !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
358 		/*
359 		 * hwaccel has no need for preallocated room for CCMP
360 		 * header or MIC fields
361 		 */
362 		return 0;
363 	}
364 
365 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
366 	len = skb->len - hdrlen;
367 
368 	if (info->control.hw_key)
369 		tail = 0;
370 	else
371 		tail = CCMP_MIC_LEN;
372 
373 	if (WARN_ON(skb_tailroom(skb) < tail ||
374 		    skb_headroom(skb) < CCMP_HDR_LEN))
375 		return -1;
376 
377 	pos = skb_push(skb, CCMP_HDR_LEN);
378 	memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
379 	hdr = (struct ieee80211_hdr *) pos;
380 	pos += hdrlen;
381 
382 	/* PN = PN + 1 */
383 	pn = key->u.ccmp.tx_pn;
384 
385 	for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
386 		pn[i]++;
387 		if (pn[i])
388 			break;
389 	}
390 
391 	ccmp_pn2hdr(pos, pn, key->conf.keyidx);
392 
393 	/* hwaccel - with software CCMP header */
394 	if (info->control.hw_key)
395 		return 0;
396 
397 	pos += CCMP_HDR_LEN;
398 	ccmp_special_blocks(skb, pn, key->u.ccmp.tx_crypto_buf, 0);
399 	ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, key->u.ccmp.tx_crypto_buf, pos, len,
400 				  pos, skb_put(skb, CCMP_MIC_LEN));
401 
402 	return 0;
403 }
404 
405 
406 ieee80211_tx_result
407 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
408 {
409 	struct sk_buff *skb = tx->skb;
410 
411 	ieee80211_tx_set_protected(tx);
412 
413 	do {
414 		if (ccmp_encrypt_skb(tx, skb) < 0)
415 			return TX_DROP;
416 	} while ((skb = skb->next));
417 
418 	return TX_CONTINUE;
419 }
420 
421 
422 ieee80211_rx_result
423 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
424 {
425 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
426 	int hdrlen;
427 	struct ieee80211_key *key = rx->key;
428 	struct sk_buff *skb = rx->skb;
429 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
430 	u8 pn[CCMP_PN_LEN];
431 	int data_len;
432 	int queue;
433 
434 	hdrlen = ieee80211_hdrlen(hdr->frame_control);
435 
436 	if (!ieee80211_is_data(hdr->frame_control) &&
437 	    !ieee80211_is_robust_mgmt_frame(hdr))
438 		return RX_CONTINUE;
439 
440 	data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
441 	if (!rx->sta || data_len < 0)
442 		return RX_DROP_UNUSABLE;
443 
444 	ccmp_hdr2pn(pn, skb->data + hdrlen);
445 
446 	queue = ieee80211_is_mgmt(hdr->frame_control) ?
447 		NUM_RX_DATA_QUEUES : rx->queue;
448 
449 	if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
450 		key->u.ccmp.replays++;
451 		return RX_DROP_UNUSABLE;
452 	}
453 
454 	if (!(status->flag & RX_FLAG_DECRYPTED)) {
455 		/* hardware didn't decrypt/verify MIC */
456 		ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1);
457 
458 		if (ieee80211_aes_ccm_decrypt(
459 			    key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf,
460 			    skb->data + hdrlen + CCMP_HDR_LEN, data_len,
461 			    skb->data + skb->len - CCMP_MIC_LEN,
462 			    skb->data + hdrlen + CCMP_HDR_LEN))
463 			return RX_DROP_UNUSABLE;
464 	}
465 
466 	memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
467 
468 	/* Remove CCMP header and MIC */
469 	skb_trim(skb, skb->len - CCMP_MIC_LEN);
470 	memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
471 	skb_pull(skb, CCMP_HDR_LEN);
472 
473 	return RX_CONTINUE;
474 }
475 
476 
477 static void bip_aad(struct sk_buff *skb, u8 *aad)
478 {
479 	/* BIP AAD: FC(masked) || A1 || A2 || A3 */
480 
481 	/* FC type/subtype */
482 	aad[0] = skb->data[0];
483 	/* Mask FC Retry, PwrMgt, MoreData flags to zero */
484 	aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
485 	/* A1 || A2 || A3 */
486 	memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
487 }
488 
489 
490 static inline void bip_ipn_swap(u8 *d, const u8 *s)
491 {
492 	*d++ = s[5];
493 	*d++ = s[4];
494 	*d++ = s[3];
495 	*d++ = s[2];
496 	*d++ = s[1];
497 	*d = s[0];
498 }
499 
500 
501 ieee80211_tx_result
502 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
503 {
504 	struct sk_buff *skb = tx->skb;
505 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
506 	struct ieee80211_key *key = tx->key;
507 	struct ieee80211_mmie *mmie;
508 	u8 *pn, aad[20];
509 	int i;
510 
511 	if (info->control.hw_key)
512 		return 0;
513 
514 	if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
515 		return TX_DROP;
516 
517 	mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
518 	mmie->element_id = WLAN_EID_MMIE;
519 	mmie->length = sizeof(*mmie) - 2;
520 	mmie->key_id = cpu_to_le16(key->conf.keyidx);
521 
522 	/* PN = PN + 1 */
523 	pn = key->u.aes_cmac.tx_pn;
524 
525 	for (i = sizeof(key->u.aes_cmac.tx_pn) - 1; i >= 0; i--) {
526 		pn[i]++;
527 		if (pn[i])
528 			break;
529 	}
530 	bip_ipn_swap(mmie->sequence_number, pn);
531 
532 	bip_aad(skb, aad);
533 
534 	/*
535 	 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
536 	 */
537 	ieee80211_aes_cmac(key->u.aes_cmac.tfm, key->u.aes_cmac.tx_crypto_buf,
538 			   aad, skb->data + 24, skb->len - 24, mmie->mic);
539 
540 	return TX_CONTINUE;
541 }
542 
543 
544 ieee80211_rx_result
545 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
546 {
547 	struct sk_buff *skb = rx->skb;
548 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
549 	struct ieee80211_key *key = rx->key;
550 	struct ieee80211_mmie *mmie;
551 	u8 aad[20], mic[8], ipn[6];
552 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
553 
554 	if (!ieee80211_is_mgmt(hdr->frame_control))
555 		return RX_CONTINUE;
556 
557 	if (skb->len < 24 + sizeof(*mmie))
558 		return RX_DROP_UNUSABLE;
559 
560 	mmie = (struct ieee80211_mmie *)
561 		(skb->data + skb->len - sizeof(*mmie));
562 	if (mmie->element_id != WLAN_EID_MMIE ||
563 	    mmie->length != sizeof(*mmie) - 2)
564 		return RX_DROP_UNUSABLE; /* Invalid MMIE */
565 
566 	bip_ipn_swap(ipn, mmie->sequence_number);
567 
568 	if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
569 		key->u.aes_cmac.replays++;
570 		return RX_DROP_UNUSABLE;
571 	}
572 
573 	if (!(status->flag & RX_FLAG_DECRYPTED)) {
574 		/* hardware didn't decrypt/verify MIC */
575 		bip_aad(skb, aad);
576 		ieee80211_aes_cmac(key->u.aes_cmac.tfm,
577 				   key->u.aes_cmac.rx_crypto_buf, aad,
578 				   skb->data + 24, skb->len - 24, mic);
579 		if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
580 			key->u.aes_cmac.icverrors++;
581 			return RX_DROP_UNUSABLE;
582 		}
583 	}
584 
585 	memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
586 
587 	/* Remove MMIE */
588 	skb_trim(skb, skb->len - sizeof(*mmie));
589 
590 	return RX_CONTINUE;
591 }
592