1 /*
2 * Copyright 2002-2004, Instant802 Networks, Inc.
3 *
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 */
8
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 <linux/ieee80211.h>
15 #include <asm/unaligned.h>
16 #include <net/mac80211.h>
17
18 #include "ieee80211_i.h"
19 #include "michael.h"
20 #include "tkip.h"
21 #include "aes_ccm.h"
22 #include "wpa.h"
23
24 ieee80211_tx_result
ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data * tx)25 ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
26 {
27 u8 *data, *key, *mic, key_offset;
28 size_t data_len;
29 unsigned int hdrlen;
30 struct ieee80211_hdr *hdr;
31 struct sk_buff *skb = tx->skb;
32 int authenticator;
33 int wpa_test = 0;
34 int tail;
35
36 hdr = (struct ieee80211_hdr *)skb->data;
37 if (!tx->key || tx->key->conf.alg != ALG_TKIP || skb->len < 24 ||
38 !ieee80211_is_data_present(hdr->frame_control))
39 return TX_CONTINUE;
40
41 hdrlen = ieee80211_hdrlen(hdr->frame_control);
42 if (skb->len < hdrlen)
43 return TX_DROP;
44
45 data = skb->data + hdrlen;
46 data_len = skb->len - hdrlen;
47
48 if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
49 !(tx->flags & IEEE80211_TX_FRAGMENTED) &&
50 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) &&
51 !wpa_test) {
52 /* hwaccel - with no need for preallocated room for MMIC */
53 return TX_CONTINUE;
54 }
55
56 tail = MICHAEL_MIC_LEN;
57 if (!(tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
58 tail += TKIP_ICV_LEN;
59
60 if (WARN_ON(skb_tailroom(skb) < tail ||
61 skb_headroom(skb) < TKIP_IV_LEN))
62 return TX_DROP;
63
64 #if 0
65 authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
66 #else
67 authenticator = 1;
68 #endif
69 key_offset = authenticator ?
70 NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY :
71 NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY;
72 key = &tx->key->conf.key[key_offset];
73 mic = skb_put(skb, MICHAEL_MIC_LEN);
74 michael_mic(key, hdr, data, data_len, mic);
75
76 return TX_CONTINUE;
77 }
78
79
80 ieee80211_rx_result
ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data * rx)81 ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
82 {
83 u8 *data, *key = NULL, key_offset;
84 size_t data_len;
85 unsigned int hdrlen;
86 struct ieee80211_hdr *hdr;
87 u8 mic[MICHAEL_MIC_LEN];
88 struct sk_buff *skb = rx->skb;
89 int authenticator = 1, wpa_test = 0;
90
91 /* No way to verify the MIC if the hardware stripped it */
92 if (rx->status->flag & RX_FLAG_MMIC_STRIPPED)
93 return RX_CONTINUE;
94
95 hdr = (struct ieee80211_hdr *)skb->data;
96 if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
97 !ieee80211_has_protected(hdr->frame_control) ||
98 !ieee80211_is_data_present(hdr->frame_control))
99 return RX_CONTINUE;
100
101 hdrlen = ieee80211_hdrlen(hdr->frame_control);
102 if (skb->len < hdrlen + MICHAEL_MIC_LEN)
103 return RX_DROP_UNUSABLE;
104
105 data = skb->data + hdrlen;
106 data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
107
108 #if 0
109 authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
110 #else
111 authenticator = 1;
112 #endif
113 key_offset = authenticator ?
114 NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY :
115 NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY;
116 key = &rx->key->conf.key[key_offset];
117 michael_mic(key, hdr, data, data_len, mic);
118 if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
119 if (!(rx->flags & IEEE80211_RX_RA_MATCH))
120 return RX_DROP_UNUSABLE;
121
122 mac80211_ev_michael_mic_failure(rx->sdata, rx->key->conf.keyidx,
123 (void *) skb->data);
124 return RX_DROP_UNUSABLE;
125 }
126
127 /* remove Michael MIC from payload */
128 skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
129
130 /* update IV in key information to be able to detect replays */
131 rx->key->u.tkip.rx[rx->queue].iv32 = rx->tkip_iv32;
132 rx->key->u.tkip.rx[rx->queue].iv16 = rx->tkip_iv16;
133
134 return RX_CONTINUE;
135 }
136
137
tkip_encrypt_skb(struct ieee80211_tx_data * tx,struct sk_buff * skb)138 static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
139 {
140 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
141 struct ieee80211_key *key = tx->key;
142 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
143 unsigned int hdrlen;
144 int len, tail;
145 u8 *pos;
146
147 if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
148 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
149 /* hwaccel - with no need for preallocated room for IV/ICV */
150 info->control.hw_key = &tx->key->conf;
151 return 0;
152 }
153
154 hdrlen = ieee80211_hdrlen(hdr->frame_control);
155 len = skb->len - hdrlen;
156
157 if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
158 tail = 0;
159 else
160 tail = TKIP_ICV_LEN;
161
162 if (WARN_ON(skb_tailroom(skb) < tail ||
163 skb_headroom(skb) < TKIP_IV_LEN))
164 return -1;
165
166 pos = skb_push(skb, TKIP_IV_LEN);
167 memmove(pos, pos + TKIP_IV_LEN, hdrlen);
168 pos += hdrlen;
169
170 /* Increase IV for the frame */
171 key->u.tkip.tx.iv16++;
172 if (key->u.tkip.tx.iv16 == 0)
173 key->u.tkip.tx.iv32++;
174
175 if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
176 /* hwaccel - with preallocated room for IV */
177 ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16);
178
179 info->control.hw_key = &tx->key->conf;
180 return 0;
181 }
182
183 /* Add room for ICV */
184 skb_put(skb, TKIP_ICV_LEN);
185
186 hdr = (struct ieee80211_hdr *) skb->data;
187 ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
188 key, pos, len, hdr->addr2);
189 return 0;
190 }
191
192
193 ieee80211_tx_result
ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data * tx)194 ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
195 {
196 struct sk_buff *skb = tx->skb;
197 int i;
198
199 ieee80211_tx_set_protected(tx);
200
201 if (tkip_encrypt_skb(tx, skb) < 0)
202 return TX_DROP;
203
204 if (tx->extra_frag) {
205 for (i = 0; i < tx->num_extra_frag; i++) {
206 if (tkip_encrypt_skb(tx, tx->extra_frag[i]))
207 return TX_DROP;
208 }
209 }
210
211 return TX_CONTINUE;
212 }
213
214
215 ieee80211_rx_result
ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data * rx)216 ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
217 {
218 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
219 int hdrlen, res, hwaccel = 0, wpa_test = 0;
220 struct ieee80211_key *key = rx->key;
221 struct sk_buff *skb = rx->skb;
222
223 hdrlen = ieee80211_hdrlen(hdr->frame_control);
224
225 if (!ieee80211_is_data(hdr->frame_control))
226 return RX_CONTINUE;
227
228 if (!rx->sta || skb->len - hdrlen < 12)
229 return RX_DROP_UNUSABLE;
230
231 if (rx->status->flag & RX_FLAG_DECRYPTED) {
232 if (rx->status->flag & RX_FLAG_IV_STRIPPED) {
233 /*
234 * Hardware took care of all processing, including
235 * replay protection, and stripped the ICV/IV so
236 * we cannot do any checks here.
237 */
238 return RX_CONTINUE;
239 }
240
241 /* let TKIP code verify IV, but skip decryption */
242 hwaccel = 1;
243 }
244
245 res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
246 key, skb->data + hdrlen,
247 skb->len - hdrlen, rx->sta->sta.addr,
248 hdr->addr1, hwaccel, rx->queue,
249 &rx->tkip_iv32,
250 &rx->tkip_iv16);
251 if (res != TKIP_DECRYPT_OK || wpa_test)
252 return RX_DROP_UNUSABLE;
253
254 /* Trim ICV */
255 skb_trim(skb, skb->len - TKIP_ICV_LEN);
256
257 /* Remove IV */
258 memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
259 skb_pull(skb, TKIP_IV_LEN);
260
261 return RX_CONTINUE;
262 }
263
264
ccmp_special_blocks(struct sk_buff * skb,u8 * pn,u8 * scratch,int encrypted)265 static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
266 int encrypted)
267 {
268 __le16 mask_fc;
269 int a4_included;
270 u8 qos_tid;
271 u8 *b_0, *aad;
272 u16 data_len, len_a;
273 unsigned int hdrlen;
274 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
275
276 b_0 = scratch + 3 * AES_BLOCK_LEN;
277 aad = scratch + 4 * AES_BLOCK_LEN;
278
279 /*
280 * Mask FC: zero subtype b4 b5 b6
281 * Retry, PwrMgt, MoreData; set Protected
282 */
283 mask_fc = hdr->frame_control;
284 mask_fc &= ~cpu_to_le16(0x0070 | IEEE80211_FCTL_RETRY |
285 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
286 mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
287
288 hdrlen = ieee80211_hdrlen(hdr->frame_control);
289 len_a = hdrlen - 2;
290 a4_included = ieee80211_has_a4(hdr->frame_control);
291
292 if (ieee80211_is_data_qos(hdr->frame_control))
293 qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
294 else
295 qos_tid = 0;
296
297 data_len = skb->len - hdrlen - CCMP_HDR_LEN;
298 if (encrypted)
299 data_len -= CCMP_MIC_LEN;
300
301 /* First block, b_0 */
302 b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
303 /* Nonce: QoS Priority | A2 | PN */
304 b_0[1] = qos_tid;
305 memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
306 memcpy(&b_0[8], pn, CCMP_PN_LEN);
307 /* l(m) */
308 put_unaligned_be16(data_len, &b_0[14]);
309
310 /* AAD (extra authenticate-only data) / masked 802.11 header
311 * FC | A1 | A2 | A3 | SC | [A4] | [QC] */
312 put_unaligned_be16(len_a, &aad[0]);
313 put_unaligned(mask_fc, (__le16 *)&aad[2]);
314 memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
315
316 /* Mask Seq#, leave Frag# */
317 aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
318 aad[23] = 0;
319
320 if (a4_included) {
321 memcpy(&aad[24], hdr->addr4, ETH_ALEN);
322 aad[30] = qos_tid;
323 aad[31] = 0;
324 } else {
325 memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
326 aad[24] = qos_tid;
327 }
328 }
329
330
ccmp_pn2hdr(u8 * hdr,u8 * pn,int key_id)331 static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
332 {
333 hdr[0] = pn[5];
334 hdr[1] = pn[4];
335 hdr[2] = 0;
336 hdr[3] = 0x20 | (key_id << 6);
337 hdr[4] = pn[3];
338 hdr[5] = pn[2];
339 hdr[6] = pn[1];
340 hdr[7] = pn[0];
341 }
342
343
ccmp_hdr2pn(u8 * pn,u8 * hdr)344 static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
345 {
346 pn[0] = hdr[7];
347 pn[1] = hdr[6];
348 pn[2] = hdr[5];
349 pn[3] = hdr[4];
350 pn[4] = hdr[1];
351 pn[5] = hdr[0];
352 }
353
354
ccmp_encrypt_skb(struct ieee80211_tx_data * tx,struct sk_buff * skb)355 static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
356 {
357 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
358 struct ieee80211_key *key = tx->key;
359 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
360 int hdrlen, len, tail;
361 u8 *pos, *pn;
362 int i;
363
364 if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
365 !(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
366 /* hwaccel - with no need for preallocated room for CCMP
367 * header or MIC fields */
368 info->control.hw_key = &tx->key->conf;
369 return 0;
370 }
371
372 hdrlen = ieee80211_hdrlen(hdr->frame_control);
373 len = skb->len - hdrlen;
374
375 if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
376 tail = 0;
377 else
378 tail = CCMP_MIC_LEN;
379
380 if (WARN_ON(skb_tailroom(skb) < tail ||
381 skb_headroom(skb) < CCMP_HDR_LEN))
382 return -1;
383
384 pos = skb_push(skb, CCMP_HDR_LEN);
385 memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
386 hdr = (struct ieee80211_hdr *) pos;
387 pos += hdrlen;
388
389 /* PN = PN + 1 */
390 pn = key->u.ccmp.tx_pn;
391
392 for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
393 pn[i]++;
394 if (pn[i])
395 break;
396 }
397
398 ccmp_pn2hdr(pos, pn, key->conf.keyidx);
399
400 if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
401 /* hwaccel - with preallocated room for CCMP header */
402 info->control.hw_key = &tx->key->conf;
403 return 0;
404 }
405
406 pos += CCMP_HDR_LEN;
407 ccmp_special_blocks(skb, pn, key->u.ccmp.tx_crypto_buf, 0);
408 ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, key->u.ccmp.tx_crypto_buf, pos, len,
409 pos, skb_put(skb, CCMP_MIC_LEN));
410
411 return 0;
412 }
413
414
415 ieee80211_tx_result
ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data * tx)416 ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
417 {
418 struct sk_buff *skb = tx->skb;
419 int i;
420
421 ieee80211_tx_set_protected(tx);
422
423 if (ccmp_encrypt_skb(tx, skb) < 0)
424 return TX_DROP;
425
426 if (tx->extra_frag) {
427 for (i = 0; i < tx->num_extra_frag; i++) {
428 if (ccmp_encrypt_skb(tx, tx->extra_frag[i]))
429 return TX_DROP;
430 }
431 }
432
433 return TX_CONTINUE;
434 }
435
436
437 ieee80211_rx_result
ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data * rx)438 ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
439 {
440 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
441 int hdrlen;
442 struct ieee80211_key *key = rx->key;
443 struct sk_buff *skb = rx->skb;
444 u8 pn[CCMP_PN_LEN];
445 int data_len;
446
447 hdrlen = ieee80211_hdrlen(hdr->frame_control);
448
449 if (!ieee80211_is_data(hdr->frame_control))
450 return RX_CONTINUE;
451
452 data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
453 if (!rx->sta || data_len < 0)
454 return RX_DROP_UNUSABLE;
455
456 if ((rx->status->flag & RX_FLAG_DECRYPTED) &&
457 (rx->status->flag & RX_FLAG_IV_STRIPPED))
458 return RX_CONTINUE;
459
460 ccmp_hdr2pn(pn, skb->data + hdrlen);
461
462 if (memcmp(pn, key->u.ccmp.rx_pn[rx->queue], CCMP_PN_LEN) <= 0) {
463 key->u.ccmp.replays++;
464 return RX_DROP_UNUSABLE;
465 }
466
467 if (!(rx->status->flag & RX_FLAG_DECRYPTED)) {
468 /* hardware didn't decrypt/verify MIC */
469 ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1);
470
471 if (ieee80211_aes_ccm_decrypt(
472 key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf,
473 skb->data + hdrlen + CCMP_HDR_LEN, data_len,
474 skb->data + skb->len - CCMP_MIC_LEN,
475 skb->data + hdrlen + CCMP_HDR_LEN))
476 return RX_DROP_UNUSABLE;
477 }
478
479 memcpy(key->u.ccmp.rx_pn[rx->queue], pn, CCMP_PN_LEN);
480
481 /* Remove CCMP header and MIC */
482 skb_trim(skb, skb->len - CCMP_MIC_LEN);
483 memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
484 skb_pull(skb, CCMP_HDR_LEN);
485
486 return RX_CONTINUE;
487 }
488