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;
91 * it makes no sense to check for MIC errors on anything other
94 if (!ieee80211_is_data_present(hdr->frame_control))
98 * No way to verify the MIC if the hardware stripped it or
99 * the IV with the key index. In this case we have solely rely
100 * on the driver to set RX_FLAG_MMIC_ERROR in the event of a
101 * MIC failure report.
103 if (status->flag & (RX_FLAG_MMIC_STRIPPED | RX_FLAG_IV_STRIPPED)) {
104 if (status->flag & RX_FLAG_MMIC_ERROR)
107 if (!(status->flag & RX_FLAG_IV_STRIPPED))
114 * Some hardware seems to generate Michael MIC failure reports; even
115 * though, the frame was not encrypted with TKIP and therefore has no
116 * MIC. Ignore the flag them to avoid triggering countermeasures.
118 if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
119 !(status->flag & RX_FLAG_DECRYPTED))
122 if (rx->sdata->vif.type == NL80211_IFTYPE_AP && rx->key->conf.keyidx) {
124 * APs with pairwise keys should never receive Michael MIC
125 * errors for non-zero keyidx because these are reserved for
126 * group keys and only the AP is sending real multicast
127 * frames in the BSS. (
129 return RX_DROP_UNUSABLE;
132 if (status->flag & RX_FLAG_MMIC_ERROR)
135 hdrlen = ieee80211_hdrlen(hdr->frame_control);
136 if (skb->len < hdrlen + MICHAEL_MIC_LEN)
137 return RX_DROP_UNUSABLE;
139 data = skb->data + hdrlen;
140 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
141 key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
142 michael_mic(key, hdr, data, data_len, mic);
143 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0)
146 /* remove Michael MIC from payload */
147 skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
150 /* update IV in key information to be able to detect replays */
151 rx->key->u.tkip.rx[rx->queue].iv32 = rx->tkip_iv32;
152 rx->key->u.tkip.rx[rx->queue].iv16 = rx->tkip_iv16;
158 * In some cases the key can be unset - e.g. a multicast packet, in
159 * a driver that supports HW encryption. Send up the key idx only if
162 mac80211_ev_michael_mic_failure(rx->sdata,
163 rx->key ? rx->key->conf.keyidx : -1,
164 (void *) skb->data, NULL, GFP_ATOMIC);
165 return RX_DROP_UNUSABLE;
169 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
171 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
172 struct ieee80211_key *key = tx->key;
173 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
179 if (info->control.hw_key &&
180 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
181 /* hwaccel - with no need for software-generated IV */
185 hdrlen = ieee80211_hdrlen(hdr->frame_control);
186 len = skb->len - hdrlen;
188 if (info->control.hw_key)
193 if (WARN_ON(skb_tailroom(skb) < tail ||
194 skb_headroom(skb) < TKIP_IV_LEN))
197 pos = skb_push(skb, TKIP_IV_LEN);
198 memmove(pos, pos + TKIP_IV_LEN, hdrlen);
201 /* Increase IV for the frame */
202 spin_lock_irqsave(&key->u.tkip.txlock, flags);
203 key->u.tkip.tx.iv16++;
204 if (key->u.tkip.tx.iv16 == 0)
205 key->u.tkip.tx.iv32++;
206 pos = ieee80211_tkip_add_iv(pos, key);
207 spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
209 /* hwaccel - with software IV */
210 if (info->control.hw_key)
213 /* Add room for ICV */
214 skb_put(skb, TKIP_ICV_LEN);
216 return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
222 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
224 struct sk_buff *skb = tx->skb;
226 ieee80211_tx_set_protected(tx);
229 if (tkip_encrypt_skb(tx, skb) < 0)
231 } while ((skb = skb->next));
238 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
240 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
241 int hdrlen, res, hwaccel = 0;
242 struct ieee80211_key *key = rx->key;
243 struct sk_buff *skb = rx->skb;
244 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
246 hdrlen = ieee80211_hdrlen(hdr->frame_control);
248 if (!ieee80211_is_data(hdr->frame_control))
251 if (!rx->sta || skb->len - hdrlen < 12)
252 return RX_DROP_UNUSABLE;
255 * Let TKIP code verify IV, but skip decryption.
256 * In the case where hardware checks the IV as well,
257 * we don't even get here, see ieee80211_rx_h_decrypt()
259 if (status->flag & RX_FLAG_DECRYPTED)
262 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
263 key, skb->data + hdrlen,
264 skb->len - hdrlen, rx->sta->sta.addr,
265 hdr->addr1, hwaccel, rx->queue,
268 if (res != TKIP_DECRYPT_OK)
269 return RX_DROP_UNUSABLE;
272 skb_trim(skb, skb->len - TKIP_ICV_LEN);
275 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
276 skb_pull(skb, TKIP_IV_LEN);
282 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
286 int a4_included, mgmt;
291 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
293 b_0 = scratch + 3 * AES_BLOCK_LEN;
294 aad = scratch + 4 * AES_BLOCK_LEN;
297 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
298 * Retry, PwrMgt, MoreData; set Protected
300 mgmt = ieee80211_is_mgmt(hdr->frame_control);
301 mask_fc = hdr->frame_control;
302 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
303 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
305 mask_fc &= ~cpu_to_le16(0x0070);
306 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
308 hdrlen = ieee80211_hdrlen(hdr->frame_control);
310 a4_included = ieee80211_has_a4(hdr->frame_control);
312 if (ieee80211_is_data_qos(hdr->frame_control))
313 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
317 data_len = skb->len - hdrlen - CCMP_HDR_LEN;
319 data_len -= CCMP_MIC_LEN;
321 /* First block, b_0 */
322 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
323 /* Nonce: Nonce Flags | A2 | PN
324 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
326 b_0[1] = qos_tid | (mgmt << 4);
327 memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
328 memcpy(&b_0[8], pn, CCMP_PN_LEN);
330 put_unaligned_be16(data_len, &b_0[14]);
332 /* AAD (extra authenticate-only data) / masked 802.11 header
333 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
334 put_unaligned_be16(len_a, &aad[0]);
335 put_unaligned(mask_fc, (__le16 *)&aad[2]);
336 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
338 /* Mask Seq#, leave Frag# */
339 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
343 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
347 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
353 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
358 hdr[3] = 0x20 | (key_id << 6);
366 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
377 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
379 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
380 struct ieee80211_key *key = tx->key;
381 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
382 int hdrlen, len, tail;
386 if (info->control.hw_key &&
387 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
389 * hwaccel has no need for preallocated room for CCMP
390 * header or MIC fields
395 hdrlen = ieee80211_hdrlen(hdr->frame_control);
396 len = skb->len - hdrlen;
398 if (info->control.hw_key)
403 if (WARN_ON(skb_tailroom(skb) < tail ||
404 skb_headroom(skb) < CCMP_HDR_LEN))
407 pos = skb_push(skb, CCMP_HDR_LEN);
408 memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
409 hdr = (struct ieee80211_hdr *) pos;
413 pn = key->u.ccmp.tx_pn;
415 for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
421 ccmp_pn2hdr(pos, pn, key->conf.keyidx);
423 /* hwaccel - with software CCMP header */
424 if (info->control.hw_key)
428 ccmp_special_blocks(skb, pn, key->u.ccmp.tx_crypto_buf, 0);
429 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, key->u.ccmp.tx_crypto_buf, pos, len,
430 pos, skb_put(skb, CCMP_MIC_LEN));
437 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
439 struct sk_buff *skb = tx->skb;
441 ieee80211_tx_set_protected(tx);
444 if (ccmp_encrypt_skb(tx, skb) < 0)
446 } while ((skb = skb->next));
453 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
455 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
457 struct ieee80211_key *key = rx->key;
458 struct sk_buff *skb = rx->skb;
459 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
464 hdrlen = ieee80211_hdrlen(hdr->frame_control);
466 if (!ieee80211_is_data(hdr->frame_control) &&
467 !ieee80211_is_robust_mgmt_frame(hdr))
470 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
471 if (!rx->sta || data_len < 0)
472 return RX_DROP_UNUSABLE;
474 ccmp_hdr2pn(pn, skb->data + hdrlen);
476 queue = ieee80211_is_mgmt(hdr->frame_control) ?
477 NUM_RX_DATA_QUEUES : rx->queue;
479 if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
480 key->u.ccmp.replays++;
481 return RX_DROP_UNUSABLE;
484 if (!(status->flag & RX_FLAG_DECRYPTED)) {
485 /* hardware didn't decrypt/verify MIC */
486 ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1);
488 if (ieee80211_aes_ccm_decrypt(
489 key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf,
490 skb->data + hdrlen + CCMP_HDR_LEN, data_len,
491 skb->data + skb->len - CCMP_MIC_LEN,
492 skb->data + hdrlen + CCMP_HDR_LEN))
493 return RX_DROP_UNUSABLE;
496 memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
498 /* Remove CCMP header and MIC */
499 skb_trim(skb, skb->len - CCMP_MIC_LEN);
500 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
501 skb_pull(skb, CCMP_HDR_LEN);
507 static void bip_aad(struct sk_buff *skb, u8 *aad)
509 /* BIP AAD: FC(masked) || A1 || A2 || A3 */
511 /* FC type/subtype */
512 aad[0] = skb->data[0];
513 /* Mask FC Retry, PwrMgt, MoreData flags to zero */
514 aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
516 memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
520 static inline void bip_ipn_swap(u8 *d, const u8 *s)
532 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
534 struct sk_buff *skb = tx->skb;
535 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
536 struct ieee80211_key *key = tx->key;
537 struct ieee80211_mmie *mmie;
541 if (info->control.hw_key)
544 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
547 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
548 mmie->element_id = WLAN_EID_MMIE;
549 mmie->length = sizeof(*mmie) - 2;
550 mmie->key_id = cpu_to_le16(key->conf.keyidx);
553 pn = key->u.aes_cmac.tx_pn;
555 for (i = sizeof(key->u.aes_cmac.tx_pn) - 1; i >= 0; i--) {
560 bip_ipn_swap(mmie->sequence_number, pn);
565 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
567 ieee80211_aes_cmac(key->u.aes_cmac.tfm, key->u.aes_cmac.tx_crypto_buf,
568 aad, skb->data + 24, skb->len - 24, mmie->mic);
575 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
577 struct sk_buff *skb = rx->skb;
578 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
579 struct ieee80211_key *key = rx->key;
580 struct ieee80211_mmie *mmie;
581 u8 aad[20], mic[8], ipn[6];
582 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
584 if (!ieee80211_is_mgmt(hdr->frame_control))
587 if (skb->len < 24 + sizeof(*mmie))
588 return RX_DROP_UNUSABLE;
590 mmie = (struct ieee80211_mmie *)
591 (skb->data + skb->len - sizeof(*mmie));
592 if (mmie->element_id != WLAN_EID_MMIE ||
593 mmie->length != sizeof(*mmie) - 2)
594 return RX_DROP_UNUSABLE; /* Invalid MMIE */
596 bip_ipn_swap(ipn, mmie->sequence_number);
598 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
599 key->u.aes_cmac.replays++;
600 return RX_DROP_UNUSABLE;
603 if (!(status->flag & RX_FLAG_DECRYPTED)) {
604 /* hardware didn't decrypt/verify MIC */
606 ieee80211_aes_cmac(key->u.aes_cmac.tfm,
607 key->u.aes_cmac.rx_crypto_buf, aad,
608 skb->data + 24, skb->len - 24, mic);
609 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
610 key->u.aes_cmac.icverrors++;
611 return RX_DROP_UNUSABLE;
615 memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
618 skb_trim(skb, skb->len - sizeof(*mmie));