[PATCH] mac80211: consolidate encryption
[linux-2.6.git] / net / mac80211 / wpa.c
bloba07fd7484cdfa9bc5c90127fcd8884af6b3a1fa1
1 /*
2 * Copyright 2002-2004, Instant802 Networks, Inc.
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
9 #include <linux/netdevice.h>
10 #include <linux/types.h>
11 #include <linux/slab.h>
12 #include <linux/skbuff.h>
13 #include <linux/compiler.h>
14 #include <net/mac80211.h>
16 #include "ieee80211_i.h"
17 #include "michael.h"
18 #include "tkip.h"
19 #include "aes_ccm.h"
20 #include "wpa.h"
22 static int ieee80211_get_hdr_info(const struct sk_buff *skb, u8 **sa, u8 **da,
23 u8 *qos_tid, u8 **data, size_t *data_len)
25 struct ieee80211_hdr *hdr;
26 size_t hdrlen;
27 u16 fc;
28 int a4_included;
29 u8 *pos;
31 hdr = (struct ieee80211_hdr *) skb->data;
32 fc = le16_to_cpu(hdr->frame_control);
34 hdrlen = 24;
35 if ((fc & (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) ==
36 (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
37 hdrlen += ETH_ALEN;
38 *sa = hdr->addr4;
39 *da = hdr->addr3;
40 } else if (fc & IEEE80211_FCTL_FROMDS) {
41 *sa = hdr->addr3;
42 *da = hdr->addr1;
43 } else if (fc & IEEE80211_FCTL_TODS) {
44 *sa = hdr->addr2;
45 *da = hdr->addr3;
46 } else {
47 *sa = hdr->addr2;
48 *da = hdr->addr1;
51 if (fc & 0x80)
52 hdrlen += 2;
54 *data = skb->data + hdrlen;
55 *data_len = skb->len - hdrlen;
57 a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
58 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
59 if ((fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA &&
60 fc & IEEE80211_STYPE_QOS_DATA) {
61 pos = (u8 *) &hdr->addr4;
62 if (a4_included)
63 pos += 6;
64 *qos_tid = pos[0] & 0x0f;
65 *qos_tid |= 0x80; /* qos_included flag */
66 } else
67 *qos_tid = 0;
69 return skb->len < hdrlen ? -1 : 0;
73 ieee80211_txrx_result
74 ieee80211_tx_h_michael_mic_add(struct ieee80211_txrx_data *tx)
76 u8 *data, *sa, *da, *key, *mic, qos_tid;
77 size_t data_len;
78 u16 fc;
79 struct sk_buff *skb = tx->skb;
80 int authenticator;
81 int wpa_test = 0;
83 fc = tx->fc;
85 if (!tx->key || tx->key->conf.alg != ALG_TKIP || skb->len < 24 ||
86 !WLAN_FC_DATA_PRESENT(fc))
87 return TXRX_CONTINUE;
89 if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len))
90 return TXRX_DROP;
92 if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
93 !(tx->flags & IEEE80211_TXRXD_FRAGMENTED) &&
94 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) &&
95 !wpa_test) {
96 /* hwaccel - with no need for preallocated room for Michael MIC
98 return TXRX_CONTINUE;
101 if (skb_tailroom(skb) < MICHAEL_MIC_LEN) {
102 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
103 if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN,
104 MICHAEL_MIC_LEN + TKIP_ICV_LEN,
105 GFP_ATOMIC))) {
106 printk(KERN_DEBUG "%s: failed to allocate more memory "
107 "for Michael MIC\n", tx->dev->name);
108 return TXRX_DROP;
112 #if 0
113 authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
114 #else
115 authenticator = 1;
116 #endif
117 key = &tx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_TX_MIC_KEY :
118 ALG_TKIP_TEMP_AUTH_RX_MIC_KEY];
119 mic = skb_put(skb, MICHAEL_MIC_LEN);
120 michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
122 return TXRX_CONTINUE;
126 ieee80211_txrx_result
127 ieee80211_rx_h_michael_mic_verify(struct ieee80211_txrx_data *rx)
129 u8 *data, *sa, *da, *key = NULL, qos_tid;
130 size_t data_len;
131 u16 fc;
132 u8 mic[MICHAEL_MIC_LEN];
133 struct sk_buff *skb = rx->skb;
134 int authenticator = 1, wpa_test = 0;
135 DECLARE_MAC_BUF(mac);
137 fc = rx->fc;
140 * No way to verify the MIC if the hardware stripped it
142 if (rx->u.rx.status->flag & RX_FLAG_MMIC_STRIPPED)
143 return TXRX_CONTINUE;
145 if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
146 !(rx->fc & IEEE80211_FCTL_PROTECTED) || !WLAN_FC_DATA_PRESENT(fc))
147 return TXRX_CONTINUE;
149 if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len)
150 || data_len < MICHAEL_MIC_LEN)
151 return TXRX_DROP;
153 data_len -= MICHAEL_MIC_LEN;
155 #if 0
156 authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
157 #else
158 authenticator = 1;
159 #endif
160 key = &rx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_RX_MIC_KEY :
161 ALG_TKIP_TEMP_AUTH_TX_MIC_KEY];
162 michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
163 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
164 if (!(rx->flags & IEEE80211_TXRXD_RXRA_MATCH))
165 return TXRX_DROP;
167 printk(KERN_DEBUG "%s: invalid Michael MIC in data frame from "
168 "%s\n", rx->dev->name, print_mac(mac, sa));
170 mac80211_ev_michael_mic_failure(rx->dev, rx->key->conf.keyidx,
171 (void *) skb->data);
172 return TXRX_DROP;
175 /* remove Michael MIC from payload */
176 skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
178 return TXRX_CONTINUE;
182 static int tkip_encrypt_skb(struct ieee80211_txrx_data *tx,
183 struct sk_buff *skb, int test)
185 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
186 struct ieee80211_key *key = tx->key;
187 int hdrlen, len, tailneed;
188 u16 fc;
189 u8 *pos;
191 fc = le16_to_cpu(hdr->frame_control);
192 hdrlen = ieee80211_get_hdrlen(fc);
193 len = skb->len - hdrlen;
195 if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
196 tailneed = 0;
197 else
198 tailneed = TKIP_ICV_LEN;
200 if ((skb_headroom(skb) < TKIP_IV_LEN ||
201 skb_tailroom(skb) < tailneed)) {
202 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
203 if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN, tailneed,
204 GFP_ATOMIC)))
205 return -1;
208 pos = skb_push(skb, TKIP_IV_LEN);
209 memmove(pos, pos + TKIP_IV_LEN, hdrlen);
210 pos += hdrlen;
212 /* Increase IV for the frame */
213 key->u.tkip.iv16++;
214 if (key->u.tkip.iv16 == 0)
215 key->u.tkip.iv32++;
217 if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
218 hdr = (struct ieee80211_hdr *)skb->data;
220 /* hwaccel - with preallocated room for IV */
221 ieee80211_tkip_add_iv(pos, key,
222 (u8) (key->u.tkip.iv16 >> 8),
223 (u8) (((key->u.tkip.iv16 >> 8) | 0x20) &
224 0x7f),
225 (u8) key->u.tkip.iv16);
227 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
228 return 0;
231 /* Add room for ICV */
232 skb_put(skb, TKIP_ICV_LEN);
234 hdr = (struct ieee80211_hdr *) skb->data;
235 ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
236 key, pos, len, hdr->addr2);
237 return 0;
241 ieee80211_txrx_result
242 ieee80211_crypto_tkip_encrypt(struct ieee80211_txrx_data *tx)
244 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
245 u16 fc;
246 struct sk_buff *skb = tx->skb;
247 int wpa_test = 0, test = 0;
249 fc = le16_to_cpu(hdr->frame_control);
251 if (!WLAN_FC_DATA_PRESENT(fc))
252 return TXRX_CONTINUE;
254 tx->u.tx.control->icv_len = TKIP_ICV_LEN;
255 tx->u.tx.control->iv_len = TKIP_IV_LEN;
256 ieee80211_tx_set_iswep(tx);
258 if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
259 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
260 !wpa_test) {
261 /* hwaccel - with no need for preallocated room for IV/ICV */
262 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
263 return TXRX_CONTINUE;
266 if (tkip_encrypt_skb(tx, skb, test) < 0)
267 return TXRX_DROP;
269 if (tx->u.tx.extra_frag) {
270 int i;
271 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
272 if (tkip_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
273 < 0)
274 return TXRX_DROP;
278 return TXRX_CONTINUE;
282 ieee80211_txrx_result
283 ieee80211_crypto_tkip_decrypt(struct ieee80211_txrx_data *rx)
285 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
286 u16 fc;
287 int hdrlen, res, hwaccel = 0, wpa_test = 0;
288 struct ieee80211_key *key = rx->key;
289 struct sk_buff *skb = rx->skb;
290 DECLARE_MAC_BUF(mac);
292 fc = le16_to_cpu(hdr->frame_control);
293 hdrlen = ieee80211_get_hdrlen(fc);
295 if ((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
296 return TXRX_CONTINUE;
298 if (!rx->sta || skb->len - hdrlen < 12)
299 return TXRX_DROP;
301 if (rx->u.rx.status->flag & RX_FLAG_DECRYPTED) {
302 if (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED) {
304 * Hardware took care of all processing, including
305 * replay protection, and stripped the ICV/IV so
306 * we cannot do any checks here.
308 return TXRX_CONTINUE;
311 /* let TKIP code verify IV, but skip decryption */
312 hwaccel = 1;
315 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
316 key, skb->data + hdrlen,
317 skb->len - hdrlen, rx->sta->addr,
318 hwaccel, rx->u.rx.queue);
319 if (res != TKIP_DECRYPT_OK || wpa_test) {
320 printk(KERN_DEBUG "%s: TKIP decrypt failed for RX frame from "
321 "%s (res=%d)\n",
322 rx->dev->name, print_mac(mac, rx->sta->addr), res);
323 return TXRX_DROP;
326 /* Trim ICV */
327 skb_trim(skb, skb->len - TKIP_ICV_LEN);
329 /* Remove IV */
330 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
331 skb_pull(skb, TKIP_IV_LEN);
333 return TXRX_CONTINUE;
337 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
338 int encrypted)
340 u16 fc;
341 int a4_included, qos_included;
342 u8 qos_tid, *fc_pos, *data, *sa, *da;
343 int len_a;
344 size_t data_len;
345 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
347 fc_pos = (u8 *) &hdr->frame_control;
348 fc = fc_pos[0] ^ (fc_pos[1] << 8);
349 a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
350 (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
352 ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len);
353 data_len -= CCMP_HDR_LEN + (encrypted ? CCMP_MIC_LEN : 0);
354 if (qos_tid & 0x80) {
355 qos_included = 1;
356 qos_tid &= 0x0f;
357 } else
358 qos_included = 0;
359 /* First block, b_0 */
361 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
362 /* Nonce: QoS Priority | A2 | PN */
363 b_0[1] = qos_tid;
364 memcpy(&b_0[2], hdr->addr2, 6);
365 memcpy(&b_0[8], pn, CCMP_PN_LEN);
366 /* l(m) */
367 b_0[14] = (data_len >> 8) & 0xff;
368 b_0[15] = data_len & 0xff;
371 /* AAD (extra authenticate-only data) / masked 802.11 header
372 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
374 len_a = a4_included ? 28 : 22;
375 if (qos_included)
376 len_a += 2;
378 aad[0] = 0; /* (len_a >> 8) & 0xff; */
379 aad[1] = len_a & 0xff;
380 /* Mask FC: zero subtype b4 b5 b6 */
381 aad[2] = fc_pos[0] & ~(BIT(4) | BIT(5) | BIT(6));
382 /* Retry, PwrMgt, MoreData; set Protected */
383 aad[3] = (fc_pos[1] & ~(BIT(3) | BIT(4) | BIT(5))) | BIT(6);
384 memcpy(&aad[4], &hdr->addr1, 18);
386 /* Mask Seq#, leave Frag# */
387 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
388 aad[23] = 0;
389 if (a4_included) {
390 memcpy(&aad[24], hdr->addr4, 6);
391 aad[30] = 0;
392 aad[31] = 0;
393 } else
394 memset(&aad[24], 0, 8);
395 if (qos_included) {
396 u8 *dpos = &aad[a4_included ? 30 : 24];
398 /* Mask QoS Control field */
399 dpos[0] = qos_tid;
400 dpos[1] = 0;
405 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
407 hdr[0] = pn[5];
408 hdr[1] = pn[4];
409 hdr[2] = 0;
410 hdr[3] = 0x20 | (key_id << 6);
411 hdr[4] = pn[3];
412 hdr[5] = pn[2];
413 hdr[6] = pn[1];
414 hdr[7] = pn[0];
418 static inline int ccmp_hdr2pn(u8 *pn, u8 *hdr)
420 pn[0] = hdr[7];
421 pn[1] = hdr[6];
422 pn[2] = hdr[5];
423 pn[3] = hdr[4];
424 pn[4] = hdr[1];
425 pn[5] = hdr[0];
426 return (hdr[3] >> 6) & 0x03;
430 static int ccmp_encrypt_skb(struct ieee80211_txrx_data *tx,
431 struct sk_buff *skb, int test)
433 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
434 struct ieee80211_key *key = tx->key;
435 int hdrlen, len, tailneed;
436 u16 fc;
437 u8 *pos, *pn, *b_0, *aad, *scratch;
438 int i;
440 scratch = key->u.ccmp.tx_crypto_buf;
441 b_0 = scratch + 3 * AES_BLOCK_LEN;
442 aad = scratch + 4 * AES_BLOCK_LEN;
444 fc = le16_to_cpu(hdr->frame_control);
445 hdrlen = ieee80211_get_hdrlen(fc);
446 len = skb->len - hdrlen;
448 if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
449 tailneed = 0;
450 else
451 tailneed = CCMP_MIC_LEN;
453 if ((skb_headroom(skb) < CCMP_HDR_LEN ||
454 skb_tailroom(skb) < tailneed)) {
455 I802_DEBUG_INC(tx->local->tx_expand_skb_head);
456 if (unlikely(pskb_expand_head(skb, CCMP_HDR_LEN, tailneed,
457 GFP_ATOMIC)))
458 return -1;
461 pos = skb_push(skb, CCMP_HDR_LEN);
462 memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
463 hdr = (struct ieee80211_hdr *) pos;
464 pos += hdrlen;
466 /* PN = PN + 1 */
467 pn = key->u.ccmp.tx_pn;
469 for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
470 pn[i]++;
471 if (pn[i])
472 break;
475 ccmp_pn2hdr(pos, pn, key->conf.keyidx);
477 if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
478 /* hwaccel - with preallocated room for CCMP header */
479 tx->u.tx.control->key_idx = key->conf.hw_key_idx;
480 return 0;
483 pos += CCMP_HDR_LEN;
484 ccmp_special_blocks(skb, pn, b_0, aad, 0);
485 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, b_0, aad, pos, len,
486 pos, skb_put(skb, CCMP_MIC_LEN));
488 return 0;
492 ieee80211_txrx_result
493 ieee80211_crypto_ccmp_encrypt(struct ieee80211_txrx_data *tx)
495 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
496 u16 fc;
497 struct sk_buff *skb = tx->skb;
498 int test = 0;
500 fc = le16_to_cpu(hdr->frame_control);
502 if (!WLAN_FC_DATA_PRESENT(fc))
503 return TXRX_CONTINUE;
505 tx->u.tx.control->icv_len = CCMP_MIC_LEN;
506 tx->u.tx.control->iv_len = CCMP_HDR_LEN;
507 ieee80211_tx_set_iswep(tx);
509 if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
510 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
511 /* hwaccel - with no need for preallocated room for CCMP "
512 * header or MIC fields */
513 tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
514 return TXRX_CONTINUE;
517 if (ccmp_encrypt_skb(tx, skb, test) < 0)
518 return TXRX_DROP;
520 if (tx->u.tx.extra_frag) {
521 int i;
522 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
523 if (ccmp_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
524 < 0)
525 return TXRX_DROP;
529 return TXRX_CONTINUE;
533 ieee80211_txrx_result
534 ieee80211_crypto_ccmp_decrypt(struct ieee80211_txrx_data *rx)
536 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
537 u16 fc;
538 int hdrlen;
539 struct ieee80211_key *key = rx->key;
540 struct sk_buff *skb = rx->skb;
541 u8 pn[CCMP_PN_LEN];
542 int data_len;
543 DECLARE_MAC_BUF(mac);
545 fc = le16_to_cpu(hdr->frame_control);
546 hdrlen = ieee80211_get_hdrlen(fc);
548 if ((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
549 return TXRX_CONTINUE;
551 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
552 if (!rx->sta || data_len < 0)
553 return TXRX_DROP;
555 if ((rx->u.rx.status->flag & RX_FLAG_DECRYPTED) &&
556 (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED))
557 return TXRX_CONTINUE;
559 (void) ccmp_hdr2pn(pn, skb->data + hdrlen);
561 if (memcmp(pn, key->u.ccmp.rx_pn[rx->u.rx.queue], CCMP_PN_LEN) <= 0) {
562 #ifdef CONFIG_MAC80211_DEBUG
563 u8 *ppn = key->u.ccmp.rx_pn[rx->u.rx.queue];
565 printk(KERN_DEBUG "%s: CCMP replay detected for RX frame from "
566 "%s (RX PN %02x%02x%02x%02x%02x%02x <= prev. PN "
567 "%02x%02x%02x%02x%02x%02x)\n", rx->dev->name,
568 print_mac(mac, rx->sta->addr),
569 pn[0], pn[1], pn[2], pn[3], pn[4], pn[5],
570 ppn[0], ppn[1], ppn[2], ppn[3], ppn[4], ppn[5]);
571 #endif /* CONFIG_MAC80211_DEBUG */
572 key->u.ccmp.replays++;
573 return TXRX_DROP;
576 if (!(rx->u.rx.status->flag & RX_FLAG_DECRYPTED)) {
577 /* hardware didn't decrypt/verify MIC */
578 u8 *scratch, *b_0, *aad;
580 scratch = key->u.ccmp.rx_crypto_buf;
581 b_0 = scratch + 3 * AES_BLOCK_LEN;
582 aad = scratch + 4 * AES_BLOCK_LEN;
584 ccmp_special_blocks(skb, pn, b_0, aad, 1);
586 if (ieee80211_aes_ccm_decrypt(
587 key->u.ccmp.tfm, scratch, b_0, aad,
588 skb->data + hdrlen + CCMP_HDR_LEN, data_len,
589 skb->data + skb->len - CCMP_MIC_LEN,
590 skb->data + hdrlen + CCMP_HDR_LEN)) {
591 printk(KERN_DEBUG "%s: CCMP decrypt failed for RX "
592 "frame from %s\n", rx->dev->name,
593 print_mac(mac, rx->sta->addr));
594 return TXRX_DROP;
598 memcpy(key->u.ccmp.rx_pn[rx->u.rx.queue], pn, CCMP_PN_LEN);
600 /* Remove CCMP header and MIC */
601 skb_trim(skb, skb->len - CCMP_MIC_LEN);
602 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
603 skb_pull(skb, CCMP_HDR_LEN);
605 return TXRX_CONTINUE;