2 * Copyright 2002-2004, Instant802 Networks, Inc.
3 * Copyright 2008, Jouni Malinen <j@w1.fi>
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.
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>
19 #include "ieee80211_i.h"
27 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
32 struct ieee80211_hdr *hdr;
33 struct sk_buff *skb = tx->skb;
34 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
37 hdr = (struct ieee80211_hdr *)skb->data;
38 if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
39 skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control))
42 hdrlen = ieee80211_hdrlen(hdr->frame_control);
43 if (skb->len < hdrlen)
46 data = skb->data + hdrlen;
47 data_len = skb->len - hdrlen;
49 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) {
50 /* Need to use software crypto for the test */
51 info->control.hw_key = NULL;
54 if (info->control.hw_key &&
55 !(tx->flags & IEEE80211_TX_FRAGMENTED) &&
56 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
57 /* hwaccel - with no need for SW-generated MMIC */
61 tail = MICHAEL_MIC_LEN;
62 if (!info->control.hw_key)
65 if (WARN_ON(skb_tailroom(skb) < tail ||
66 skb_headroom(skb) < TKIP_IV_LEN))
69 key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY];
70 mic = skb_put(skb, MICHAEL_MIC_LEN);
71 michael_mic(key, hdr, data, data_len, mic);
72 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE))
80 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
82 u8 *data, *key = NULL;
85 u8 mic[MICHAEL_MIC_LEN];
86 struct sk_buff *skb = rx->skb;
87 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
88 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
89 int queue = rx->queue;
91 /* otherwise, TKIP is vulnerable to TID 0 vs. non-QoS replays */
92 if (rx->queue == NUM_RX_DATA_QUEUES - 1)
96 * it makes no sense to check for MIC errors on anything other
99 if (!ieee80211_is_data_present(hdr->frame_control))
103 * No way to verify the MIC if the hardware stripped it or
104 * the IV with the key index. In this case we have solely rely
105 * on the driver to set RX_FLAG_MMIC_ERROR in the event of a
106 * MIC failure report.
108 if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) {
109 if (status->flag & RX_FLAG_MMIC_ERROR)
112 if (!(status->flag & RX_FLAG_IV_STRIPPED))
119 * Some hardware seems to generate Michael MIC failure reports; even
120 * though, the frame was not encrypted with TKIP and therefore has no
121 * MIC. Ignore the flag them to avoid triggering countermeasures.
123 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
124 !(status->flag & RX_FLAG_DECRYPTED))
127 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
129 * APs with pairwise keys should never receive Michael MIC
130 * errors for non-zero keyidx because these are reserved for
131 * group keys and only the AP is sending real multicast
132 * frames in the BSS. (
134 return RX_DROP_UNUSABLE;
137 if (status->flag & RX_FLAG_MMIC_ERROR)
140 hdrlen = ieee80211_hdrlen(hdr->frame_control);
141 if (skb->len < hdrlen + MICHAEL_MIC_LEN)
142 return RX_DROP_UNUSABLE;
144 data = skb->data + hdrlen;
145 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
146 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
147 michael_mic(key, hdr, data, data_len, mic);
148 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
151 /* remove Michael MIC from payload */
152 skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
155 /* update IV in key information to be able to detect replays */
156 rx->key->u.tkip.rx[queue].iv32 = rx->tkip_iv32;
157 rx->key->u.tkip.rx[queue].iv16 = rx->tkip_iv16;
163 * In some cases the key can be unset - e.g. a multicast packet, in
164 * a driver that supports HW encryption. Send up the key idx only if
167 mac80211_ev_michael_mic_failure(rx->sdata,
168 rx->key ? rx->key->conf.keyidx : -1,
169 (void *) skb->data, NULL, GFP_ATOMIC);
170 return RX_DROP_UNUSABLE;
174 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
176 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
177 struct ieee80211_key *key = tx->key;
178 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
183 if (info->control.hw_key &&
184 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
185 /* hwaccel - with no need for software-generated IV */
189 hdrlen = ieee80211_hdrlen(hdr->frame_control);
190 len = skb->len - hdrlen;
192 if (info->control.hw_key)
197 if (WARN_ON(skb_tailroom(skb) < tail ||
198 skb_headroom(skb) < TKIP_IV_LEN))
201 pos = skb_push(skb, TKIP_IV_LEN);
202 memmove(pos, pos + TKIP_IV_LEN, hdrlen);
205 /* Increase IV for the frame */
206 key->u.tkip.tx.iv16++;
207 if (key->u.tkip.tx.iv16 == 0)
208 key->u.tkip.tx.iv32++;
210 pos = ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16);
212 /* hwaccel - with software IV */
213 if (info->control.hw_key)
216 /* Add room for ICV */
217 skb_put(skb, TKIP_ICV_LEN);
219 hdr = (struct ieee80211_hdr *) skb->data;
220 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
221 key, pos, len, hdr->addr2);
226 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
228 struct sk_buff *skb = tx->skb;
230 ieee80211_tx_set_protected(tx);
233 if (tkip_encrypt_skb(tx, skb) < 0)
235 } while ((skb = skb->next));
242 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
244 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
245 int hdrlen, res, hwaccel = 0;
246 struct ieee80211_key *key = rx->key;
247 struct sk_buff *skb = rx->skb;
248 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
249 int queue = rx->queue;
251 /* otherwise, TKIP is vulnerable to TID 0 vs. non-QoS replays */
252 if (rx->queue == NUM_RX_DATA_QUEUES - 1)
255 hdrlen = ieee80211_hdrlen(hdr->frame_control);
257 if (!ieee80211_is_data(hdr->frame_control))
260 if (!rx->sta || skb->len - hdrlen < 12)
261 return RX_DROP_UNUSABLE;
264 * Let TKIP code verify IV, but skip decryption.
265 * In the case where hardware checks the IV as well,
266 * we don't even get here, see ieee80211_rx_h_decrypt()
268 if (status->flag & RX_FLAG_DECRYPTED)
271 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
272 key, skb->data + hdrlen,
273 skb->len - hdrlen, rx->sta->sta.addr,
274 hdr->addr1, hwaccel, queue,
277 if (res != TKIP_DECRYPT_OK)
278 return RX_DROP_UNUSABLE;
281 skb_trim(skb, skb->len - TKIP_ICV_LEN);
284 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
285 skb_pull(skb, TKIP_IV_LEN);
291 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
295 int a4_included, mgmt;
300 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
302 b_0 = scratch + 3 * AES_BLOCK_LEN;
303 aad = scratch + 4 * AES_BLOCK_LEN;
306 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
307 * Retry, PwrMgt, MoreData; set Protected
309 mgmt = ieee80211_is_mgmt(hdr->frame_control);
310 mask_fc = hdr->frame_control;
311 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
312 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
314 mask_fc &= ~cpu_to_le16(0x0070);
315 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
317 hdrlen = ieee80211_hdrlen(hdr->frame_control);
319 a4_included = ieee80211_has_a4(hdr->frame_control);
321 if (ieee80211_is_data_qos(hdr->frame_control))
322 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
326 data_len = skb->len - hdrlen - CCMP_HDR_LEN;
328 data_len -= CCMP_MIC_LEN;
330 /* First block, b_0 */
331 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
332 /* Nonce: Nonce Flags | A2 | PN
333 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
335 b_0[1] = qos_tid | (mgmt << 4);
336 memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
337 memcpy(&b_0[8], pn, CCMP_PN_LEN);
339 put_unaligned_be16(data_len, &b_0[14]);
341 /* AAD (extra authenticate-only data) / masked 802.11 header
342 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
343 put_unaligned_be16(len_a, &aad[0]);
344 put_unaligned(mask_fc, (__le16 *)&aad[2]);
345 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
347 /* Mask Seq#, leave Frag# */
348 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
352 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
356 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
362 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
367 hdr[3] = 0x20 | (key_id << 6);
375 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
386 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
388 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
389 struct ieee80211_key *key = tx->key;
390 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
391 int hdrlen, len, tail;
395 if (info->control.hw_key &&
396 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
398 * hwaccel has no need for preallocated room for CCMP
399 * header or MIC fields
404 hdrlen = ieee80211_hdrlen(hdr->frame_control);
405 len = skb->len - hdrlen;
407 if (info->control.hw_key)
412 if (WARN_ON(skb_tailroom(skb) < tail ||
413 skb_headroom(skb) < CCMP_HDR_LEN))
416 pos = skb_push(skb, CCMP_HDR_LEN);
417 memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
418 hdr = (struct ieee80211_hdr *) pos;
422 pn = key->u.ccmp.tx_pn;
424 for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
430 ccmp_pn2hdr(pos, pn, key->conf.keyidx);
432 /* hwaccel - with software CCMP header */
433 if (info->control.hw_key)
437 ccmp_special_blocks(skb, pn, key->u.ccmp.tx_crypto_buf, 0);
438 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, key->u.ccmp.tx_crypto_buf, pos, len,
439 pos, skb_put(skb, CCMP_MIC_LEN));
446 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
448 struct sk_buff *skb = tx->skb;
450 ieee80211_tx_set_protected(tx);
453 if (ccmp_encrypt_skb(tx, skb) < 0)
455 } while ((skb = skb->next));
462 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
464 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
466 struct ieee80211_key *key = rx->key;
467 struct sk_buff *skb = rx->skb;
468 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
473 hdrlen = ieee80211_hdrlen(hdr->frame_control);
475 if (!ieee80211_is_data(hdr->frame_control) &&
476 !ieee80211_is_robust_mgmt_frame(hdr))
479 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
480 if (!rx->sta || data_len < 0)
481 return RX_DROP_UNUSABLE;
483 ccmp_hdr2pn(pn, skb->data + hdrlen);
485 queue = ieee80211_is_mgmt(hdr->frame_control) ?
486 NUM_RX_DATA_QUEUES : rx->queue;
488 if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
489 key->u.ccmp.replays++;
490 return RX_DROP_UNUSABLE;
493 if (!(status->flag & RX_FLAG_DECRYPTED)) {
494 /* hardware didn't decrypt/verify MIC */
495 ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1);
497 if (ieee80211_aes_ccm_decrypt(
498 key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf,
499 skb->data + hdrlen + CCMP_HDR_LEN, data_len,
500 skb->data + skb->len - CCMP_MIC_LEN,
501 skb->data + hdrlen + CCMP_HDR_LEN))
502 return RX_DROP_UNUSABLE;
505 memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
507 /* Remove CCMP header and MIC */
508 skb_trim(skb, skb->len - CCMP_MIC_LEN);
509 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
510 skb_pull(skb, CCMP_HDR_LEN);
516 static void bip_aad(struct sk_buff *skb, u8 *aad)
518 /* BIP AAD: FC(masked) || A1 || A2 || A3 */
520 /* FC type/subtype */
521 aad[0] = skb->data[0];
522 /* Mask FC Retry, PwrMgt, MoreData flags to zero */
523 aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
525 memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
529 static inline void bip_ipn_swap(u8 *d, const u8 *s)
541 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
543 struct sk_buff *skb = tx->skb;
544 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
545 struct ieee80211_key *key = tx->key;
546 struct ieee80211_mmie *mmie;
550 if (info->control.hw_key)
553 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
556 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
557 mmie->element_id = WLAN_EID_MMIE;
558 mmie->length = sizeof(*mmie) - 2;
559 mmie->key_id = cpu_to_le16(key->conf.keyidx);
562 pn = key->u.aes_cmac.tx_pn;
564 for (i = sizeof(key->u.aes_cmac.tx_pn) - 1; i >= 0; i--) {
569 bip_ipn_swap(mmie->sequence_number, pn);
574 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
576 ieee80211_aes_cmac(key->u.aes_cmac.tfm, key->u.aes_cmac.tx_crypto_buf,
577 aad, skb->data + 24, skb->len - 24, mmie->mic);
584 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
586 struct sk_buff *skb = rx->skb;
587 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
588 struct ieee80211_key *key = rx->key;
589 struct ieee80211_mmie *mmie;
590 u8 aad[20], mic[8], ipn[6];
591 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
593 if (!ieee80211_is_mgmt(hdr->frame_control))
596 if (skb->len < 24 + sizeof(*mmie))
597 return RX_DROP_UNUSABLE;
599 mmie = (struct ieee80211_mmie *)
600 (skb->data + skb->len - sizeof(*mmie));
601 if (mmie->element_id != WLAN_EID_MMIE ||
602 mmie->length != sizeof(*mmie) - 2)
603 return RX_DROP_UNUSABLE; /* Invalid MMIE */
605 bip_ipn_swap(ipn, mmie->sequence_number);
607 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
608 key->u.aes_cmac.replays++;
609 return RX_DROP_UNUSABLE;
612 if (!(status->flag & RX_FLAG_DECRYPTED)) {
613 /* hardware didn't decrypt/verify MIC */
615 ieee80211_aes_cmac(key->u.aes_cmac.tfm,
616 key->u.aes_cmac.rx_crypto_buf, aad,
617 skb->data + 24, skb->len - 24, mic);
618 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
619 key->u.aes_cmac.icverrors++;
620 return RX_DROP_UNUSABLE;
624 memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
627 skb_trim(skb, skb->len - sizeof(*mmie));