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 !(tx->flags & IEEE80211_TX_FRAGMENTED) &&
57 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
58 /* hwaccel - with no need for SW-generated MMIC */
62 tail = MICHAEL_MIC_LEN;
63 if (!info->control.hw_key)
66 if (WARN_ON(skb_tailroom(skb) < tail ||
67 skb_headroom(skb) < TKIP_IV_LEN))
70 key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY];
71 mic = skb_put(skb, MICHAEL_MIC_LEN);
72 michael_mic(key, hdr, data, data_len, mic);
73 if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE))
81 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
83 u8 *data, *key = NULL;
86 u8 mic[MICHAEL_MIC_LEN];
87 struct sk_buff *skb = rx->skb;
88 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
89 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
92 * it makes no sense to check for MIC errors on anything other
95 if (!ieee80211_is_data_present(hdr->frame_control))
99 * No way to verify the MIC if the hardware stripped it or
100 * the IV with the key index. In this case we have solely rely
101 * on the driver to set RX_FLAG_MMIC_ERROR in the event of a
102 * MIC failure report.
104 if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) {
105 if (status->flag & RX_FLAG_MMIC_ERROR)
108 if (!(status->flag & RX_FLAG_IV_STRIPPED))
115 * Some hardware seems to generate Michael MIC failure reports; even
116 * though, the frame was not encrypted with TKIP and therefore has no
117 * MIC. Ignore the flag them to avoid triggering countermeasures.
119 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
120 !(status->flag & RX_FLAG_DECRYPTED))
123 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
125 * APs with pairwise keys should never receive Michael MIC
126 * errors for non-zero keyidx because these are reserved for
127 * group keys and only the AP is sending real multicast
128 * frames in the BSS. (
130 return RX_DROP_UNUSABLE;
133 if (status->flag & RX_FLAG_MMIC_ERROR)
136 hdrlen = ieee80211_hdrlen(hdr->frame_control);
137 if (skb->len < hdrlen + MICHAEL_MIC_LEN)
138 return RX_DROP_UNUSABLE;
140 data = skb->data + hdrlen;
141 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
142 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
143 michael_mic(key, hdr, data, data_len, mic);
144 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
147 /* remove Michael MIC from payload */
148 skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
151 /* update IV in key information to be able to detect replays */
152 rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32;
153 rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
159 * In some cases the key can be unset - e.g. a multicast packet, in
160 * a driver that supports HW encryption. Send up the key idx only if
163 mac80211_ev_michael_mic_failure(rx->sdata,
164 rx->key ? rx->key->conf.keyidx : -1,
165 (void *) skb->data, NULL, GFP_ATOMIC);
166 return RX_DROP_UNUSABLE;
170 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
172 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
173 struct ieee80211_key *key = tx->key;
174 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
180 if (info->control.hw_key &&
181 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
182 /* hwaccel - with no need for software-generated IV */
186 hdrlen = ieee80211_hdrlen(hdr->frame_control);
187 len = skb->len - hdrlen;
189 if (info->control.hw_key)
194 if (WARN_ON(skb_tailroom(skb) < tail ||
195 skb_headroom(skb) < TKIP_IV_LEN))
198 pos = skb_push(skb, TKIP_IV_LEN);
199 memmove(pos, pos + TKIP_IV_LEN, hdrlen);
202 /* Increase IV for the frame */
203 spin_lock_irqsave(&key->u.tkip.txlock, flags);
204 key->u.tkip.tx.iv16++;
205 if (key->u.tkip.tx.iv16 == 0)
206 key->u.tkip.tx.iv32++;
207 pos = ieee80211_tkip_add_iv(pos, key);
208 spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
210 /* hwaccel - with software IV */
211 if (info->control.hw_key)
214 /* Add room for ICV */
215 skb_put(skb, TKIP_ICV_LEN);
217 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
223 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
225 struct sk_buff *skb = tx->skb;
227 ieee80211_tx_set_protected(tx);
230 if (tkip_encrypt_skb(tx, skb) < 0)
232 } while ((skb = skb->next));
239 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
241 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
242 int hdrlen, res, hwaccel = 0;
243 struct ieee80211_key *key = rx->key;
244 struct sk_buff *skb = rx->skb;
245 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
247 hdrlen = ieee80211_hdrlen(hdr->frame_control);
249 if (!ieee80211_is_data(hdr->frame_control))
252 if (!rx->sta || skb->len - hdrlen < 12)
253 return RX_DROP_UNUSABLE;
256 * Let TKIP code verify IV, but skip decryption.
257 * In the case where hardware checks the IV as well,
258 * we don't even get here, see ieee80211_rx_h_decrypt()
260 if (status->flag & RX_FLAG_DECRYPTED)
263 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
264 key, skb->data + hdrlen,
265 skb->len - hdrlen, rx->sta->sta.addr,
266 hdr->addr1, hwaccel, rx->security_idx,
269 if (res != TKIP_DECRYPT_OK)
270 return RX_DROP_UNUSABLE;
273 skb_trim(skb, skb->len - TKIP_ICV_LEN);
276 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
277 skb_pull(skb, TKIP_IV_LEN);
283 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
287 int a4_included, mgmt;
292 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
294 memset(scratch, 0, 6 * AES_BLOCK_SIZE);
296 b_0 = scratch + 3 * AES_BLOCK_SIZE;
297 aad = scratch + 4 * AES_BLOCK_SIZE;
300 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
301 * Retry, PwrMgt, MoreData; set Protected
303 mgmt = ieee80211_is_mgmt(hdr->frame_control);
304 mask_fc = hdr->frame_control;
305 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
306 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
308 mask_fc &= ~cpu_to_le16(0x0070);
309 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
311 hdrlen = ieee80211_hdrlen(hdr->frame_control);
313 a4_included = ieee80211_has_a4(hdr->frame_control);
315 if (ieee80211_is_data_qos(hdr->frame_control))
316 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
320 data_len = skb->len - hdrlen - CCMP_HDR_LEN;
322 data_len -= CCMP_MIC_LEN;
324 /* First block, b_0 */
325 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
326 /* Nonce: Nonce Flags | A2 | PN
327 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
329 b_0[1] = qos_tid | (mgmt << 4);
330 memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
331 memcpy(&b_0[8], pn, CCMP_PN_LEN);
333 put_unaligned_be16(data_len, &b_0[14]);
335 /* AAD (extra authenticate-only data) / masked 802.11 header
336 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
337 put_unaligned_be16(len_a, &aad[0]);
338 put_unaligned(mask_fc, (__le16 *)&aad[2]);
339 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
341 /* Mask Seq#, leave Frag# */
342 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
346 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
350 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
356 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
361 hdr[3] = 0x20 | (key_id << 6);
369 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
380 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
382 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
383 struct ieee80211_key *key = tx->key;
384 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
385 int hdrlen, len, tail;
389 u8 scratch[6 * AES_BLOCK_SIZE];
391 if (info->control.hw_key &&
392 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
394 * hwaccel has no need for preallocated room for CCMP
395 * header or MIC fields
400 hdrlen = ieee80211_hdrlen(hdr->frame_control);
401 len = skb->len - hdrlen;
403 if (info->control.hw_key)
408 if (WARN_ON(skb_tailroom(skb) < tail ||
409 skb_headroom(skb) < CCMP_HDR_LEN))
412 pos = skb_push(skb, CCMP_HDR_LEN);
413 memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
414 hdr = (struct ieee80211_hdr *) pos;
417 pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
426 ccmp_pn2hdr(pos, pn, key->conf.keyidx);
428 /* hwaccel - with software CCMP header */
429 if (info->control.hw_key)
433 ccmp_special_blocks(skb, pn, scratch, 0);
434 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
435 pos, skb_put(skb, CCMP_MIC_LEN));
442 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
444 struct sk_buff *skb = tx->skb;
446 ieee80211_tx_set_protected(tx);
449 if (ccmp_encrypt_skb(tx, skb) < 0)
451 } while ((skb = skb->next));
458 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
460 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
462 struct ieee80211_key *key = rx->key;
463 struct sk_buff *skb = rx->skb;
464 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
469 hdrlen = ieee80211_hdrlen(hdr->frame_control);
471 if (!ieee80211_is_data(hdr->frame_control) &&
472 !ieee80211_is_robust_mgmt_frame(hdr))
475 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
476 if (!rx->sta || data_len < 0)
477 return RX_DROP_UNUSABLE;
479 ccmp_hdr2pn(pn, skb->data + hdrlen);
481 queue = rx->security_idx;
483 if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
484 key->u.ccmp.replays++;
485 return RX_DROP_UNUSABLE;
488 if (!(status->flag & RX_FLAG_DECRYPTED)) {
489 u8 scratch[6 * AES_BLOCK_SIZE];
490 /* hardware didn't decrypt/verify MIC */
491 ccmp_special_blocks(skb, pn, scratch, 1);
493 if (ieee80211_aes_ccm_decrypt(
494 key->u.ccmp.tfm, scratch,
495 skb->data + hdrlen + CCMP_HDR_LEN, data_len,
496 skb->data + skb->len - CCMP_MIC_LEN,
497 skb->data + hdrlen + CCMP_HDR_LEN))
498 return RX_DROP_UNUSABLE;
501 memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
503 /* Remove CCMP header and MIC */
504 skb_trim(skb, skb->len - CCMP_MIC_LEN);
505 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
506 skb_pull(skb, CCMP_HDR_LEN);
512 static void bip_aad(struct sk_buff *skb, u8 *aad)
514 /* BIP AAD: FC(masked) || A1 || A2 || A3 */
516 /* FC type/subtype */
517 aad[0] = skb->data[0];
518 /* Mask FC Retry, PwrMgt, MoreData flags to zero */
519 aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
521 memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
525 static inline void bip_ipn_set64(u8 *d, u64 pn)
535 static inline void bip_ipn_swap(u8 *d, const u8 *s)
547 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
549 struct sk_buff *skb = tx->skb;
550 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
551 struct ieee80211_key *key = tx->key;
552 struct ieee80211_mmie *mmie;
556 if (info->control.hw_key)
559 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
562 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
563 mmie->element_id = WLAN_EID_MMIE;
564 mmie->length = sizeof(*mmie) - 2;
565 mmie->key_id = cpu_to_le16(key->conf.keyidx);
568 pn64 = atomic64_inc_return(&key->u.aes_cmac.tx_pn);
570 bip_ipn_set64(mmie->sequence_number, pn64);
575 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
577 ieee80211_aes_cmac(key->u.aes_cmac.tfm, aad,
578 skb->data + 24, skb->len - 24, mmie->mic);
585 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
587 struct sk_buff *skb = rx->skb;
588 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
589 struct ieee80211_key *key = rx->key;
590 struct ieee80211_mmie *mmie;
591 u8 aad[20], mic[8], ipn[6];
592 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
594 if (!ieee80211_is_mgmt(hdr->frame_control))
597 if (skb->len < 24 + sizeof(*mmie))
598 return RX_DROP_UNUSABLE;
600 mmie = (struct ieee80211_mmie *)
601 (skb->data + skb->len - sizeof(*mmie));
602 if (mmie->element_id != WLAN_EID_MMIE ||
603 mmie->length != sizeof(*mmie) - 2)
604 return RX_DROP_UNUSABLE; /* Invalid MMIE */
606 bip_ipn_swap(ipn, mmie->sequence_number);
608 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
609 key->u.aes_cmac.replays++;
610 return RX_DROP_UNUSABLE;
613 if (!(status->flag & RX_FLAG_DECRYPTED)) {
614 /* hardware didn't decrypt/verify MIC */
616 ieee80211_aes_cmac(key->u.aes_cmac.tfm, 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));