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>
18 #include <crypto/aes.h>
20 #include "ieee80211_i.h"
28 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
33 struct ieee80211_hdr *hdr;
34 struct sk_buff *skb = tx->skb;
35 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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))
43 hdrlen = ieee80211_hdrlen(hdr->frame_control);
44 if (skb->len < hdrlen)
47 data = skb->data + hdrlen;
48 data_len = skb->len - hdrlen;
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;
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 */
63 tail = MICHAEL_MIC_LEN;
64 if (!info->control.hw_key)
67 if (WARN_ON(skb_tailroom(skb) < tail ||
68 skb_headroom(skb) < TKIP_IV_LEN))
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))
82 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
84 u8 *data, *key = NULL;
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;
93 * it makes no sense to check for MIC errors on anything other
96 if (!ieee80211_is_data_present(hdr->frame_control))
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.
105 if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) {
106 if (status->flag & RX_FLAG_MMIC_ERROR)
109 if (!(status->flag & RX_FLAG_IV_STRIPPED) && rx->key)
116 * Some hardware seems to generate Michael MIC failure reports; even
117 * though, the frame was not encrypted with TKIP and therefore has no
118 * MIC. Ignore the flag them to avoid triggering countermeasures.
120 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
121 !(status->flag & RX_FLAG_DECRYPTED))
124 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
126 * APs with pairwise keys should never receive Michael MIC
127 * errors for non-zero keyidx because these are reserved for
128 * group keys and only the AP is sending real multicast
129 * frames in the BSS. (
131 return RX_DROP_UNUSABLE;
134 if (status->flag & RX_FLAG_MMIC_ERROR)
137 hdrlen = ieee80211_hdrlen(hdr->frame_control);
138 if (skb->len < hdrlen + MICHAEL_MIC_LEN)
139 return RX_DROP_UNUSABLE;
141 if (skb_linearize(rx->skb))
142 return RX_DROP_UNUSABLE;
143 hdr = (void *)skb->data;
145 data = skb->data + hdrlen;
146 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
147 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
148 michael_mic(key, hdr, data, data_len, mic);
149 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
152 /* remove Michael MIC from payload */
153 skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
156 /* update IV in key information to be able to detect replays */
157 rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32;
158 rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
164 * In some cases the key can be unset - e.g. a multicast packet, in
165 * a driver that supports HW encryption. Send up the key idx only if
168 mac80211_ev_michael_mic_failure(rx->sdata,
169 rx->key ? rx->key->conf.keyidx : -1,
170 (void *) skb->data, NULL, GFP_ATOMIC);
171 return RX_DROP_UNUSABLE;
175 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
177 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
178 struct ieee80211_key *key = tx->key;
179 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
185 if (info->control.hw_key &&
186 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
187 /* hwaccel - with no need for software-generated IV */
191 hdrlen = ieee80211_hdrlen(hdr->frame_control);
192 len = skb->len - hdrlen;
194 if (info->control.hw_key)
199 if (WARN_ON(skb_tailroom(skb) < tail ||
200 skb_headroom(skb) < TKIP_IV_LEN))
203 pos = skb_push(skb, TKIP_IV_LEN);
204 memmove(pos, pos + TKIP_IV_LEN, hdrlen);
207 /* Increase IV for the frame */
208 spin_lock_irqsave(&key->u.tkip.txlock, flags);
209 key->u.tkip.tx.iv16++;
210 if (key->u.tkip.tx.iv16 == 0)
211 key->u.tkip.tx.iv32++;
212 pos = ieee80211_tkip_add_iv(pos, key);
213 spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
215 /* hwaccel - with software IV */
216 if (info->control.hw_key)
219 /* Add room for ICV */
220 skb_put(skb, TKIP_ICV_LEN);
222 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
228 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
232 ieee80211_tx_set_protected(tx);
234 skb_queue_walk(&tx->skbs, skb) {
235 if (tkip_encrypt_skb(tx, skb) < 0)
244 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
246 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
247 int hdrlen, res, hwaccel = 0;
248 struct ieee80211_key *key = rx->key;
249 struct sk_buff *skb = rx->skb;
250 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
252 hdrlen = ieee80211_hdrlen(hdr->frame_control);
254 if (!ieee80211_is_data(hdr->frame_control))
257 if (!rx->sta || skb->len - hdrlen < 12)
258 return RX_DROP_UNUSABLE;
260 /* it may be possible to optimize this a bit more */
261 if (skb_linearize(rx->skb))
262 return RX_DROP_UNUSABLE;
263 hdr = (void *)skb->data;
266 * Let TKIP code verify IV, but skip decryption.
267 * In the case where hardware checks the IV as well,
268 * we don't even get here, see ieee80211_rx_h_decrypt()
270 if (status->flag & RX_FLAG_DECRYPTED)
273 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
274 key, skb->data + hdrlen,
275 skb->len - hdrlen, rx->sta->sta.addr,
276 hdr->addr1, hwaccel, rx->security_idx,
279 if (res != TKIP_DECRYPT_OK)
280 return RX_DROP_UNUSABLE;
283 skb_trim(skb, skb->len - TKIP_ICV_LEN);
286 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
287 skb_pull(skb, TKIP_IV_LEN);
293 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
297 int a4_included, mgmt;
302 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
304 memset(scratch, 0, 6 * AES_BLOCK_SIZE);
306 b_0 = scratch + 3 * AES_BLOCK_SIZE;
307 aad = scratch + 4 * AES_BLOCK_SIZE;
310 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
311 * Retry, PwrMgt, MoreData; set Protected
313 mgmt = ieee80211_is_mgmt(hdr->frame_control);
314 mask_fc = hdr->frame_control;
315 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
316 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
318 mask_fc &= ~cpu_to_le16(0x0070);
319 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
321 hdrlen = ieee80211_hdrlen(hdr->frame_control);
323 a4_included = ieee80211_has_a4(hdr->frame_control);
325 if (ieee80211_is_data_qos(hdr->frame_control))
326 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
330 data_len = skb->len - hdrlen - CCMP_HDR_LEN;
332 data_len -= CCMP_MIC_LEN;
334 /* First block, b_0 */
335 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
336 /* Nonce: Nonce Flags | A2 | PN
337 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
339 b_0[1] = qos_tid | (mgmt << 4);
340 memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
341 memcpy(&b_0[8], pn, CCMP_PN_LEN);
343 put_unaligned_be16(data_len, &b_0[14]);
345 /* AAD (extra authenticate-only data) / masked 802.11 header
346 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
347 put_unaligned_be16(len_a, &aad[0]);
348 put_unaligned(mask_fc, (__le16 *)&aad[2]);
349 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
351 /* Mask Seq#, leave Frag# */
352 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
356 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
360 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
366 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
371 hdr[3] = 0x20 | (key_id << 6);
379 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
390 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
392 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
393 struct ieee80211_key *key = tx->key;
394 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
395 int hdrlen, len, tail;
399 u8 scratch[6 * AES_BLOCK_SIZE];
401 if (info->control.hw_key &&
402 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
403 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)) {
405 * hwaccel has no need for preallocated room for CCMP
406 * header or MIC fields
411 hdrlen = ieee80211_hdrlen(hdr->frame_control);
412 len = skb->len - hdrlen;
414 if (info->control.hw_key)
419 if (WARN_ON(skb_tailroom(skb) < tail ||
420 skb_headroom(skb) < CCMP_HDR_LEN))
423 pos = skb_push(skb, CCMP_HDR_LEN);
424 memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
426 /* the HW only needs room for the IV, but not the actual IV */
427 if (info->control.hw_key &&
428 (info->control.hw_key->flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE))
431 hdr = (struct ieee80211_hdr *) pos;
434 pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
443 ccmp_pn2hdr(pos, pn, key->conf.keyidx);
445 /* hwaccel - with software CCMP header */
446 if (info->control.hw_key)
450 ccmp_special_blocks(skb, pn, scratch, 0);
451 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
452 pos, skb_put(skb, CCMP_MIC_LEN));
459 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
463 ieee80211_tx_set_protected(tx);
465 skb_queue_walk(&tx->skbs, skb) {
466 if (ccmp_encrypt_skb(tx, skb) < 0)
475 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
477 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
479 struct ieee80211_key *key = rx->key;
480 struct sk_buff *skb = rx->skb;
481 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
486 hdrlen = ieee80211_hdrlen(hdr->frame_control);
488 if (!ieee80211_is_data(hdr->frame_control) &&
489 !ieee80211_is_robust_mgmt_frame(hdr))
492 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
493 if (!rx->sta || data_len < 0)
494 return RX_DROP_UNUSABLE;
496 if (status->flag & RX_FLAG_DECRYPTED) {
497 if (!pskb_may_pull(rx->skb, hdrlen + CCMP_HDR_LEN))
498 return RX_DROP_UNUSABLE;
500 if (skb_linearize(rx->skb))
501 return RX_DROP_UNUSABLE;
504 ccmp_hdr2pn(pn, skb->data + hdrlen);
506 queue = rx->security_idx;
508 if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
509 key->u.ccmp.replays++;
510 return RX_DROP_UNUSABLE;
513 if (!(status->flag & RX_FLAG_DECRYPTED)) {
514 u8 scratch[6 * AES_BLOCK_SIZE];
515 /* hardware didn't decrypt/verify MIC */
516 ccmp_special_blocks(skb, pn, scratch, 1);
518 if (ieee80211_aes_ccm_decrypt(
519 key->u.ccmp.tfm, scratch,
520 skb->data + hdrlen + CCMP_HDR_LEN, data_len,
521 skb->data + skb->len - CCMP_MIC_LEN,
522 skb->data + hdrlen + CCMP_HDR_LEN))
523 return RX_DROP_UNUSABLE;
526 memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
528 /* Remove CCMP header and MIC */
529 if (pskb_trim(skb, skb->len - CCMP_MIC_LEN))
530 return RX_DROP_UNUSABLE;
531 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
532 skb_pull(skb, CCMP_HDR_LEN);
538 static void bip_aad(struct sk_buff *skb, u8 *aad)
540 /* BIP AAD: FC(masked) || A1 || A2 || A3 */
542 /* FC type/subtype */
543 aad[0] = skb->data[0];
544 /* Mask FC Retry, PwrMgt, MoreData flags to zero */
545 aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
547 memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
551 static inline void bip_ipn_set64(u8 *d, u64 pn)
561 static inline void bip_ipn_swap(u8 *d, const u8 *s)
573 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
576 struct ieee80211_tx_info *info;
577 struct ieee80211_key *key = tx->key;
578 struct ieee80211_mmie *mmie;
582 if (WARN_ON(skb_queue_len(&tx->skbs) != 1))
585 skb = skb_peek(&tx->skbs);
587 info = IEEE80211_SKB_CB(skb);
589 if (info->control.hw_key)
592 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
595 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
596 mmie->element_id = WLAN_EID_MMIE;
597 mmie->length = sizeof(*mmie) - 2;
598 mmie->key_id = cpu_to_le16(key->conf.keyidx);
601 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
603 bip_ipn_set64(mmie->sequence_number, pn64);
608 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
610 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
611 skb->data + 24, skb->len - 24, mmie->mic);
618 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
620 struct sk_buff *skb = rx->skb;
621 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
622 struct ieee80211_key *key = rx->key;
623 struct ieee80211_mmie *mmie;
624 u8 aad[20], mic[8], ipn[6];
625 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
627 if (!ieee80211_is_mgmt(hdr->frame_control))
630 /* management frames are already linear */
632 if (skb->len < 24 + sizeof(*mmie))
633 return RX_DROP_UNUSABLE;
635 mmie = (struct ieee80211_mmie *)
636 (skb->data + skb->len - sizeof(*mmie));
637 if (mmie->element_id != WLAN_EID_MMIE ||
638 mmie->length != sizeof(*mmie) - 2)
639 return RX_DROP_UNUSABLE; /* Invalid MMIE */
641 bip_ipn_swap(ipn, mmie->sequence_number);
643 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
644 key->u.aes_cmac.replays++;
645 return RX_DROP_UNUSABLE;
648 if (!(status->flag & RX_FLAG_DECRYPTED)) {
649 /* hardware didn't decrypt/verify MIC */
651 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
652 skb->data + 24, skb->len - 24, mic);
653 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
654 key->u.aes_cmac.icverrors++;
655 return RX_DROP_UNUSABLE;
659 memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
662 skb_trim(skb, skb->len - sizeof(*mmie));
668 ieee80211_crypto_hw_encrypt(struct ieee80211_tx_data *tx)
671 struct ieee80211_tx_info *info = NULL;
673 skb_queue_walk(&tx->skbs, skb) {
674 info = IEEE80211_SKB_CB(skb);
676 /* handle hw-only algorithm */
677 if (!info->control.hw_key)
681 ieee80211_tx_set_protected(tx);