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)
29 u8 *data, *key, *mic, key_offset;
32 struct ieee80211_hdr *hdr;
33 struct sk_buff *skb = tx->skb;
34 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
38 hdr = (struct ieee80211_hdr *)skb->data;
39 if (!tx->key || tx->key->conf.alg != ALG_TKIP || skb->len < 24 ||
40 !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 (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 */
57 tail = MICHAEL_MIC_LEN;
58 if (!info->control.hw_key)
61 if (WARN_ON(skb_tailroom(skb) < tail ||
62 skb_headroom(skb) < TKIP_IV_LEN))
66 authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
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);
82 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
84 u8 *data, *key = NULL, key_offset;
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;
93 /* No way to verify the MIC if the hardware stripped it */
94 if (status->flag & RX_FLAG_MMIC_STRIPPED)
97 if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
98 !ieee80211_has_protected(hdr->frame_control) ||
99 !ieee80211_is_data_present(hdr->frame_control))
102 hdrlen = ieee80211_hdrlen(hdr->frame_control);
103 if (skb->len < hdrlen + MICHAEL_MIC_LEN)
104 return RX_DROP_UNUSABLE;
106 data = skb->data + hdrlen;
107 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
110 authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
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 (!(rx->flags & IEEE80211_RX_RA_MATCH))
121 return RX_DROP_UNUSABLE;
123 mac80211_ev_michael_mic_failure(rx->sdata, rx->key->conf.keyidx,
124 (void *) skb->data, NULL,
126 return RX_DROP_UNUSABLE;
129 /* remove Michael MIC from payload */
130 skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
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;
140 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
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);
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 */
155 hdrlen = ieee80211_hdrlen(hdr->frame_control);
156 len = skb->len - hdrlen;
158 if (info->control.hw_key)
163 if (WARN_ON(skb_tailroom(skb) < tail ||
164 skb_headroom(skb) < TKIP_IV_LEN))
167 pos = skb_push(skb, TKIP_IV_LEN);
168 memmove(pos, pos + TKIP_IV_LEN, hdrlen);
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++;
176 pos = ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16);
178 /* hwaccel - with software IV */
179 if (info->control.hw_key)
182 /* Add room for ICV */
183 skb_put(skb, TKIP_ICV_LEN);
185 hdr = (struct ieee80211_hdr *) skb->data;
186 ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
187 key, pos, len, hdr->addr2);
193 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
195 struct sk_buff *skb = tx->skb;
197 ieee80211_tx_set_protected(tx);
200 if (tkip_encrypt_skb(tx, skb) < 0)
202 } while ((skb = skb->next));
209 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
211 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
212 int hdrlen, res, hwaccel = 0, wpa_test = 0;
213 struct ieee80211_key *key = rx->key;
214 struct sk_buff *skb = rx->skb;
215 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
217 hdrlen = ieee80211_hdrlen(hdr->frame_control);
219 if (!ieee80211_is_data(hdr->frame_control))
222 if (!rx->sta || skb->len - hdrlen < 12)
223 return RX_DROP_UNUSABLE;
225 if (status->flag & RX_FLAG_DECRYPTED) {
226 if (status->flag & RX_FLAG_IV_STRIPPED) {
228 * Hardware took care of all processing, including
229 * replay protection, and stripped the ICV/IV so
230 * we cannot do any checks here.
235 /* let TKIP code verify IV, but skip decryption */
239 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
240 key, skb->data + hdrlen,
241 skb->len - hdrlen, rx->sta->sta.addr,
242 hdr->addr1, hwaccel, rx->queue,
245 if (res != TKIP_DECRYPT_OK || wpa_test)
246 return RX_DROP_UNUSABLE;
249 skb_trim(skb, skb->len - TKIP_ICV_LEN);
252 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
253 skb_pull(skb, TKIP_IV_LEN);
259 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
263 int a4_included, mgmt;
268 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
270 b_0 = scratch + 3 * AES_BLOCK_LEN;
271 aad = scratch + 4 * AES_BLOCK_LEN;
274 * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
275 * Retry, PwrMgt, MoreData; set Protected
277 mgmt = ieee80211_is_mgmt(hdr->frame_control);
278 mask_fc = hdr->frame_control;
279 mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
280 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
282 mask_fc &= ~cpu_to_le16(0x0070);
283 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
285 hdrlen = ieee80211_hdrlen(hdr->frame_control);
287 a4_included = ieee80211_has_a4(hdr->frame_control);
289 if (ieee80211_is_data_qos(hdr->frame_control))
290 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
294 data_len = skb->len - hdrlen - CCMP_HDR_LEN;
296 data_len -= CCMP_MIC_LEN;
298 /* First block, b_0 */
299 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
300 /* Nonce: Nonce Flags | A2 | PN
301 * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
303 b_0[1] = qos_tid | (mgmt << 4);
304 memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
305 memcpy(&b_0[8], pn, CCMP_PN_LEN);
307 put_unaligned_be16(data_len, &b_0[14]);
309 /* AAD (extra authenticate-only data) / masked 802.11 header
310 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
311 put_unaligned_be16(len_a, &aad[0]);
312 put_unaligned(mask_fc, (__le16 *)&aad[2]);
313 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
315 /* Mask Seq#, leave Frag# */
316 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
320 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
324 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
330 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
335 hdr[3] = 0x20 | (key_id << 6);
343 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
354 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
356 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
357 struct ieee80211_key *key = tx->key;
358 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
359 int hdrlen, len, tail;
363 if (info->control.hw_key &&
364 !(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
366 * hwaccel has no need for preallocated room for CCMP
367 * header or MIC fields
372 hdrlen = ieee80211_hdrlen(hdr->frame_control);
373 len = skb->len - hdrlen;
375 if (info->control.hw_key)
380 if (WARN_ON(skb_tailroom(skb) < tail ||
381 skb_headroom(skb) < CCMP_HDR_LEN))
384 pos = skb_push(skb, CCMP_HDR_LEN);
385 memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
386 hdr = (struct ieee80211_hdr *) pos;
390 pn = key->u.ccmp.tx_pn;
392 for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
398 ccmp_pn2hdr(pos, pn, key->conf.keyidx);
400 /* hwaccel - with software CCMP header */
401 if (info->control.hw_key)
405 ccmp_special_blocks(skb, pn, key->u.ccmp.tx_crypto_buf, 0);
406 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, key->u.ccmp.tx_crypto_buf, pos, len,
407 pos, skb_put(skb, CCMP_MIC_LEN));
414 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
416 struct sk_buff *skb = tx->skb;
418 ieee80211_tx_set_protected(tx);
421 if (ccmp_encrypt_skb(tx, skb) < 0)
423 } while ((skb = skb->next));
430 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
432 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
434 struct ieee80211_key *key = rx->key;
435 struct sk_buff *skb = rx->skb;
436 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
440 hdrlen = ieee80211_hdrlen(hdr->frame_control);
442 if (!ieee80211_is_data(hdr->frame_control) &&
443 !ieee80211_is_robust_mgmt_frame(hdr))
446 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
447 if (!rx->sta || data_len < 0)
448 return RX_DROP_UNUSABLE;
450 if ((status->flag & RX_FLAG_DECRYPTED) &&
451 (status->flag & RX_FLAG_IV_STRIPPED))
454 ccmp_hdr2pn(pn, skb->data + hdrlen);
456 if (memcmp(pn, key->u.ccmp.rx_pn[rx->queue], CCMP_PN_LEN) <= 0) {
457 key->u.ccmp.replays++;
458 return RX_DROP_UNUSABLE;
461 if (!(status->flag & RX_FLAG_DECRYPTED)) {
462 /* hardware didn't decrypt/verify MIC */
463 ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1);
465 if (ieee80211_aes_ccm_decrypt(
466 key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf,
467 skb->data + hdrlen + CCMP_HDR_LEN, data_len,
468 skb->data + skb->len - CCMP_MIC_LEN,
469 skb->data + hdrlen + CCMP_HDR_LEN))
470 return RX_DROP_UNUSABLE;
473 memcpy(key->u.ccmp.rx_pn[rx->queue], pn, CCMP_PN_LEN);
475 /* Remove CCMP header and MIC */
476 skb_trim(skb, skb->len - CCMP_MIC_LEN);
477 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
478 skb_pull(skb, CCMP_HDR_LEN);
484 static void bip_aad(struct sk_buff *skb, u8 *aad)
486 /* BIP AAD: FC(masked) || A1 || A2 || A3 */
488 /* FC type/subtype */
489 aad[0] = skb->data[0];
490 /* Mask FC Retry, PwrMgt, MoreData flags to zero */
491 aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
493 memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
497 static inline void bip_ipn_swap(u8 *d, const u8 *s)
509 ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
511 struct sk_buff *skb = tx->skb;
512 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
513 struct ieee80211_key *key = tx->key;
514 struct ieee80211_mmie *mmie;
518 if (info->control.hw_key)
521 if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
524 mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
525 mmie->element_id = WLAN_EID_MMIE;
526 mmie->length = sizeof(*mmie) - 2;
527 mmie->key_id = cpu_to_le16(key->conf.keyidx);
530 pn = key->u.aes_cmac.tx_pn;
532 for (i = sizeof(key->u.aes_cmac.tx_pn) - 1; i >= 0; i--) {
537 bip_ipn_swap(mmie->sequence_number, pn);
542 * MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
544 ieee80211_aes_cmac(key->u.aes_cmac.tfm, key->u.aes_cmac.tx_crypto_buf,
545 aad, skb->data + 24, skb->len - 24, mmie->mic);
552 ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
554 struct sk_buff *skb = rx->skb;
555 struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
556 struct ieee80211_key *key = rx->key;
557 struct ieee80211_mmie *mmie;
558 u8 aad[20], mic[8], ipn[6];
559 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
561 if (!ieee80211_is_mgmt(hdr->frame_control))
564 if ((status->flag & RX_FLAG_DECRYPTED) &&
565 (status->flag & RX_FLAG_IV_STRIPPED))
568 if (skb->len < 24 + sizeof(*mmie))
569 return RX_DROP_UNUSABLE;
571 mmie = (struct ieee80211_mmie *)
572 (skb->data + skb->len - sizeof(*mmie));
573 if (mmie->element_id != WLAN_EID_MMIE ||
574 mmie->length != sizeof(*mmie) - 2)
575 return RX_DROP_UNUSABLE; /* Invalid MMIE */
577 bip_ipn_swap(ipn, mmie->sequence_number);
579 if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
580 key->u.aes_cmac.replays++;
581 return RX_DROP_UNUSABLE;
584 if (!(status->flag & RX_FLAG_DECRYPTED)) {
585 /* hardware didn't decrypt/verify MIC */
587 ieee80211_aes_cmac(key->u.aes_cmac.tfm,
588 key->u.aes_cmac.rx_crypto_buf, aad,
589 skb->data + 24, skb->len - 24, mic);
590 if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
591 key->u.aes_cmac.icverrors++;
592 return RX_DROP_UNUSABLE;
596 memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
599 skb_trim(skb, skb->len - sizeof(*mmie));