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mm owner: fix race between swapoff and exit
[linux-2.6/next.git] / net / ieee80211 / ieee80211_crypt_tkip.c
blobbba0152e2d713b5798e6501711312e59a4267cef
1 /*
2 * Host AP crypt: host-based TKIP encryption implementation for Host AP driver
3 *
4 * Copyright (c) 2003-2004, Jouni Malinen <j@w1.fi>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation. See README and COPYING for
9 * more details.
10 */
11
12 #include <linux/err.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/random.h>
17 #include <linux/scatterlist.h>
18 #include <linux/skbuff.h>
19 #include <linux/netdevice.h>
20 #include <linux/mm.h>
21 #include <linux/if_ether.h>
22 #include <linux/if_arp.h>
23 #include <asm/string.h>
24
25 #include <net/ieee80211.h>
26
27 #include <linux/crypto.h>
28 #include <linux/crc32.h>
29
30 MODULE_AUTHOR("Jouni Malinen");
31 MODULE_DESCRIPTION("Host AP crypt: TKIP");
32 MODULE_LICENSE("GPL");
33
34 struct ieee80211_tkip_data {
35 #define TKIP_KEY_LEN 32
36 u8 key[TKIP_KEY_LEN];
37 int key_set;
38
39 u32 tx_iv32;
40 u16 tx_iv16;
41 u16 tx_ttak[5];
42 int tx_phase1_done;
43
44 u32 rx_iv32;
45 u16 rx_iv16;
46 u16 rx_ttak[5];
47 int rx_phase1_done;
48 u32 rx_iv32_new;
49 u16 rx_iv16_new;
50
51 u32 dot11RSNAStatsTKIPReplays;
52 u32 dot11RSNAStatsTKIPICVErrors;
53 u32 dot11RSNAStatsTKIPLocalMICFailures;
54
55 int key_idx;
56
57 struct crypto_blkcipher *rx_tfm_arc4;
58 struct crypto_hash *rx_tfm_michael;
59 struct crypto_blkcipher *tx_tfm_arc4;
60 struct crypto_hash *tx_tfm_michael;
61
62 /* scratch buffers for virt_to_page() (crypto API) */
63 u8 rx_hdr[16], tx_hdr[16];
64
65 unsigned long flags;
66 };
67
68 static unsigned long ieee80211_tkip_set_flags(unsigned long flags, void *priv)
69 {
70 struct ieee80211_tkip_data *_priv = priv;
71 unsigned long old_flags = _priv->flags;
72 _priv->flags = flags;
73 return old_flags;
74 }
75
76 static unsigned long ieee80211_tkip_get_flags(void *priv)
77 {
78 struct ieee80211_tkip_data *_priv = priv;
79 return _priv->flags;
80 }
81
82 static void *ieee80211_tkip_init(int key_idx)
83 {
84 struct ieee80211_tkip_data *priv;
85
86 priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
87 if (priv == NULL)
88 goto fail;
89
90 priv->key_idx = key_idx;
91
92 priv->tx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
93 CRYPTO_ALG_ASYNC);
94 if (IS_ERR(priv->tx_tfm_arc4)) {
95 printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
96 "crypto API arc4\n");
97 priv->tx_tfm_arc4 = NULL;
98 goto fail;
99 }
100
101 priv->tx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
102 CRYPTO_ALG_ASYNC);
103 if (IS_ERR(priv->tx_tfm_michael)) {
104 printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
105 "crypto API michael_mic\n");
106 priv->tx_tfm_michael = NULL;
107 goto fail;
108 }
109
110 priv->rx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
111 CRYPTO_ALG_ASYNC);
112 if (IS_ERR(priv->rx_tfm_arc4)) {
113 printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
114 "crypto API arc4\n");
115 priv->rx_tfm_arc4 = NULL;
116 goto fail;
117 }
118
119 priv->rx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
120 CRYPTO_ALG_ASYNC);
121 if (IS_ERR(priv->rx_tfm_michael)) {
122 printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
123 "crypto API michael_mic\n");
124 priv->rx_tfm_michael = NULL;
125 goto fail;
126 }
127
128 return priv;
129
130 fail:
131 if (priv) {
132 if (priv->tx_tfm_michael)
133 crypto_free_hash(priv->tx_tfm_michael);
134 if (priv->tx_tfm_arc4)
135 crypto_free_blkcipher(priv->tx_tfm_arc4);
136 if (priv->rx_tfm_michael)
137 crypto_free_hash(priv->rx_tfm_michael);
138 if (priv->rx_tfm_arc4)
139 crypto_free_blkcipher(priv->rx_tfm_arc4);
140 kfree(priv);
141 }
142
143 return NULL;
144 }
145
146 static void ieee80211_tkip_deinit(void *priv)
147 {
148 struct ieee80211_tkip_data *_priv = priv;
149 if (_priv) {
150 if (_priv->tx_tfm_michael)
151 crypto_free_hash(_priv->tx_tfm_michael);
152 if (_priv->tx_tfm_arc4)
153 crypto_free_blkcipher(_priv->tx_tfm_arc4);
154 if (_priv->rx_tfm_michael)
155 crypto_free_hash(_priv->rx_tfm_michael);
156 if (_priv->rx_tfm_arc4)
157 crypto_free_blkcipher(_priv->rx_tfm_arc4);
158 }
159 kfree(priv);
160 }
161
162 static inline u16 RotR1(u16 val)
163 {
164 return (val >> 1) | (val << 15);
165 }
166
167 static inline u8 Lo8(u16 val)
168 {
169 return val & 0xff;
170 }
171
172 static inline u8 Hi8(u16 val)
173 {
174 return val >> 8;
175 }
176
177 static inline u16 Lo16(u32 val)
178 {
179 return val & 0xffff;
180 }
181
182 static inline u16 Hi16(u32 val)
183 {
184 return val >> 16;
185 }
186
187 static inline u16 Mk16(u8 hi, u8 lo)
188 {
189 return lo | (((u16) hi) << 8);
190 }
191
192 static inline u16 Mk16_le(__le16 * v)
193 {
194 return le16_to_cpu(*v);
195 }
196
197 static const u16 Sbox[256] = {
198 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
199 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
200 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
201 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
202 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
203 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
204 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
205 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
206 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
207 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
208 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
209 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
210 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
211 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
212 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
213 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
214 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
215 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
216 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
217 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
218 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
219 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
220 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
221 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
222 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
223 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
224 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
225 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
226 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
227 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
228 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
229 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
230 };
231
232 static inline u16 _S_(u16 v)
233 {
234 u16 t = Sbox[Hi8(v)];
235 return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
236 }
237
238 #define PHASE1_LOOP_COUNT 8
239
240 static void tkip_mixing_phase1(u16 * TTAK, const u8 * TK, const u8 * TA,
241 u32 IV32)
242 {
243 int i, j;
244
245 /* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
246 TTAK[0] = Lo16(IV32);
247 TTAK[1] = Hi16(IV32);
248 TTAK[2] = Mk16(TA[1], TA[0]);
249 TTAK[3] = Mk16(TA[3], TA[2]);
250 TTAK[4] = Mk16(TA[5], TA[4]);
251
252 for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
253 j = 2 * (i & 1);
254 TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
255 TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
256 TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
257 TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
258 TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
259 }
260 }
261
262 static void tkip_mixing_phase2(u8 * WEPSeed, const u8 * TK, const u16 * TTAK,
263 u16 IV16)
264 {
265 /* Make temporary area overlap WEP seed so that the final copy can be
266 * avoided on little endian hosts. */
267 u16 *PPK = (u16 *) & WEPSeed[4];
268
269 /* Step 1 - make copy of TTAK and bring in TSC */
270 PPK[0] = TTAK[0];
271 PPK[1] = TTAK[1];
272 PPK[2] = TTAK[2];
273 PPK[3] = TTAK[3];
274 PPK[4] = TTAK[4];
275 PPK[5] = TTAK[4] + IV16;
276
277 /* Step 2 - 96-bit bijective mixing using S-box */
278 PPK[0] += _S_(PPK[5] ^ Mk16_le((__le16 *) & TK[0]));
279 PPK[1] += _S_(PPK[0] ^ Mk16_le((__le16 *) & TK[2]));
280 PPK[2] += _S_(PPK[1] ^ Mk16_le((__le16 *) & TK[4]));
281 PPK[3] += _S_(PPK[2] ^ Mk16_le((__le16 *) & TK[6]));
282 PPK[4] += _S_(PPK[3] ^ Mk16_le((__le16 *) & TK[8]));
283 PPK[5] += _S_(PPK[4] ^ Mk16_le((__le16 *) & TK[10]));
284
285 PPK[0] += RotR1(PPK[5] ^ Mk16_le((__le16 *) & TK[12]));
286 PPK[1] += RotR1(PPK[0] ^ Mk16_le((__le16 *) & TK[14]));
287 PPK[2] += RotR1(PPK[1]);
288 PPK[3] += RotR1(PPK[2]);
289 PPK[4] += RotR1(PPK[3]);
290 PPK[5] += RotR1(PPK[4]);
291
292 /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
293 * WEPSeed[0..2] is transmitted as WEP IV */
294 WEPSeed[0] = Hi8(IV16);
295 WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
296 WEPSeed[2] = Lo8(IV16);
297 WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((__le16 *) & TK[0])) >> 1);
298
299 #ifdef __BIG_ENDIAN
300 {
301 int i;
302 for (i = 0; i < 6; i++)
303 PPK[i] = (PPK[i] << 8) | (PPK[i] >> 8);
304 }
305 #endif
306 }
307
308 static int ieee80211_tkip_hdr(struct sk_buff *skb, int hdr_len,
309 u8 * rc4key, int keylen, void *priv)
310 {
311 struct ieee80211_tkip_data *tkey = priv;
312 int len;
313 u8 *pos;
314 struct ieee80211_hdr_4addr *hdr;
315
316 hdr = (struct ieee80211_hdr_4addr *)skb->data;
317
318 if (skb_headroom(skb) < 8 || skb->len < hdr_len)
319 return -1;
320
321 if (rc4key == NULL || keylen < 16)
322 return -1;
323
324 if (!tkey->tx_phase1_done) {
325 tkip_mixing_phase1(tkey->tx_ttak, tkey->key, hdr->addr2,
326 tkey->tx_iv32);
327 tkey->tx_phase1_done = 1;
328 }
329 tkip_mixing_phase2(rc4key, tkey->key, tkey->tx_ttak, tkey->tx_iv16);
330
331 len = skb->len - hdr_len;
332 pos = skb_push(skb, 8);
333 memmove(pos, pos + 8, hdr_len);
334 pos += hdr_len;
335
336 *pos++ = *rc4key;
337 *pos++ = *(rc4key + 1);
338 *pos++ = *(rc4key + 2);
339 *pos++ = (tkey->key_idx << 6) | (1 << 5) /* Ext IV included */ ;
340 *pos++ = tkey->tx_iv32 & 0xff;
341 *pos++ = (tkey->tx_iv32 >> 8) & 0xff;
342 *pos++ = (tkey->tx_iv32 >> 16) & 0xff;
343 *pos++ = (tkey->tx_iv32 >> 24) & 0xff;
344
345 tkey->tx_iv16++;
346 if (tkey->tx_iv16 == 0) {
347 tkey->tx_phase1_done = 0;
348 tkey->tx_iv32++;
349 }
350
351 return 8;
352 }
353
354 static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
355 {
356 struct ieee80211_tkip_data *tkey = priv;
357 struct blkcipher_desc desc = { .tfm = tkey->tx_tfm_arc4 };
358 int len;
359 u8 rc4key[16], *pos, *icv;
360 u32 crc;
361 struct scatterlist sg;
362 DECLARE_MAC_BUF(mac);
363
364 if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
365 if (net_ratelimit()) {
366 struct ieee80211_hdr_4addr *hdr =
367 (struct ieee80211_hdr_4addr *)skb->data;
368 printk(KERN_DEBUG ": TKIP countermeasures: dropped "
369 "TX packet to %s\n",
370 print_mac(mac, hdr->addr1));
371 }
372 return -1;
373 }
374
375 if (skb_tailroom(skb) < 4 || skb->len < hdr_len)
376 return -1;
377
378 len = skb->len - hdr_len;
379 pos = skb->data + hdr_len;
380
381 if ((ieee80211_tkip_hdr(skb, hdr_len, rc4key, 16, priv)) < 0)
382 return -1;
383
384 icv = skb_put(skb, 4);
385
386 crc = ~crc32_le(~0, pos, len);
387 icv[0] = crc;
388 icv[1] = crc >> 8;
389 icv[2] = crc >> 16;
390 icv[3] = crc >> 24;
391
392 crypto_blkcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);
393 sg_init_one(&sg, pos, len + 4);
394 return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
395 }
396
397 /*
398 * deal with seq counter wrapping correctly.
399 * refer to timer_after() for jiffies wrapping handling
400 */
401 static inline int tkip_replay_check(u32 iv32_n, u16 iv16_n,
402 u32 iv32_o, u16 iv16_o)
403 {
404 if ((s32)iv32_n - (s32)iv32_o < 0 ||
405 (iv32_n == iv32_o && iv16_n <= iv16_o))
406 return 1;
407 return 0;
408 }
409
410 static int ieee80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
411 {
412 struct ieee80211_tkip_data *tkey = priv;
413 struct blkcipher_desc desc = { .tfm = tkey->rx_tfm_arc4 };
414 u8 rc4key[16];
415 u8 keyidx, *pos;
416 u32 iv32;
417 u16 iv16;
418 struct ieee80211_hdr_4addr *hdr;
419 u8 icv[4];
420 u32 crc;
421 struct scatterlist sg;
422 int plen;
423 DECLARE_MAC_BUF(mac);
424
425 hdr = (struct ieee80211_hdr_4addr *)skb->data;
426
427 if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
428 if (net_ratelimit()) {
429 printk(KERN_DEBUG ": TKIP countermeasures: dropped "
430 "received packet from %s\n",
431 print_mac(mac, hdr->addr2));
432 }
433 return -1;
434 }
435
436 if (skb->len < hdr_len + 8 + 4)
437 return -1;
438
439 pos = skb->data + hdr_len;
440 keyidx = pos[3];
441 if (!(keyidx & (1 << 5))) {
442 if (net_ratelimit()) {
443 printk(KERN_DEBUG "TKIP: received packet without ExtIV"
444 " flag from %s\n", print_mac(mac, hdr->addr2));
445 }
446 return -2;
447 }
448 keyidx >>= 6;
449 if (tkey->key_idx != keyidx) {
450 printk(KERN_DEBUG "TKIP: RX tkey->key_idx=%d frame "
451 "keyidx=%d priv=%p\n", tkey->key_idx, keyidx, priv);
452 return -6;
453 }
454 if (!tkey->key_set) {
455 if (net_ratelimit()) {
456 printk(KERN_DEBUG "TKIP: received packet from %s"
457 " with keyid=%d that does not have a configured"
458 " key\n", print_mac(mac, hdr->addr2), keyidx);
459 }
460 return -3;
461 }
462 iv16 = (pos[0] << 8) | pos[2];
463 iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24);
464 pos += 8;
465
466 if (tkip_replay_check(iv32, iv16, tkey->rx_iv32, tkey->rx_iv16)) {
467 if (ieee80211_ratelimit_debug(IEEE80211_DL_DROP)) {
468 IEEE80211_DEBUG_DROP("TKIP: replay detected: STA=%s"
469 " previous TSC %08x%04x received TSC "
470 "%08x%04x\n", print_mac(mac, hdr->addr2),
471 tkey->rx_iv32, tkey->rx_iv16, iv32, iv16);
472 }
473 tkey->dot11RSNAStatsTKIPReplays++;
474 return -4;
475 }
476
477 if (iv32 != tkey->rx_iv32 || !tkey->rx_phase1_done) {
478 tkip_mixing_phase1(tkey->rx_ttak, tkey->key, hdr->addr2, iv32);
479 tkey->rx_phase1_done = 1;
480 }
481 tkip_mixing_phase2(rc4key, tkey->key, tkey->rx_ttak, iv16);
482
483 plen = skb->len - hdr_len - 12;
484
485 crypto_blkcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);
486 sg_init_one(&sg, pos, plen + 4);
487 if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4)) {
488 if (net_ratelimit()) {
489 printk(KERN_DEBUG ": TKIP: failed to decrypt "
490 "received packet from %s\n",
491 print_mac(mac, hdr->addr2));
492 }
493 return -7;
494 }
495
496 crc = ~crc32_le(~0, pos, plen);
497 icv[0] = crc;
498 icv[1] = crc >> 8;
499 icv[2] = crc >> 16;
500 icv[3] = crc >> 24;
501 if (memcmp(icv, pos + plen, 4) != 0) {
502 if (iv32 != tkey->rx_iv32) {
503 /* Previously cached Phase1 result was already lost, so
504 * it needs to be recalculated for the next packet. */
505 tkey->rx_phase1_done = 0;
506 }
507 if (ieee80211_ratelimit_debug(IEEE80211_DL_DROP)) {
508 IEEE80211_DEBUG_DROP("TKIP: ICV error detected: STA="
509 "%s\n", print_mac(mac, hdr->addr2));
510 }
511 tkey->dot11RSNAStatsTKIPICVErrors++;
512 return -5;
513 }
514
515 /* Update real counters only after Michael MIC verification has
516 * completed */
517 tkey->rx_iv32_new = iv32;
518 tkey->rx_iv16_new = iv16;
519
520 /* Remove IV and ICV */
521 memmove(skb->data + 8, skb->data, hdr_len);
522 skb_pull(skb, 8);
523 skb_trim(skb, skb->len - 4);
524
525 return keyidx;
526 }
527
528 static int michael_mic(struct crypto_hash *tfm_michael, u8 * key, u8 * hdr,
529 u8 * data, size_t data_len, u8 * mic)
530 {
531 struct hash_desc desc;
532 struct scatterlist sg[2];
533
534 if (tfm_michael == NULL) {
535 printk(KERN_WARNING "michael_mic: tfm_michael == NULL\n");
536 return -1;
537 }
538 sg_init_table(sg, 2);
539 sg_set_buf(&sg[0], hdr, 16);
540 sg_set_buf(&sg[1], data, data_len);
541
542 if (crypto_hash_setkey(tfm_michael, key, 8))
543 return -1;
544
545 desc.tfm = tfm_michael;
546 desc.flags = 0;
547 return crypto_hash_digest(&desc, sg, data_len + 16, mic);
548 }
549
550 static void michael_mic_hdr(struct sk_buff *skb, u8 * hdr)
551 {
552 struct ieee80211_hdr_4addr *hdr11;
553 u16 stype;
554
555 hdr11 = (struct ieee80211_hdr_4addr *)skb->data;
556 stype = WLAN_FC_GET_STYPE(le16_to_cpu(hdr11->frame_ctl));
557
558 switch (le16_to_cpu(hdr11->frame_ctl) &
559 (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
560 case IEEE80211_FCTL_TODS:
561 memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
562 memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
563 break;
564 case IEEE80211_FCTL_FROMDS:
565 memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
566 memcpy(hdr + ETH_ALEN, hdr11->addr3, ETH_ALEN); /* SA */
567 break;
568 case IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS:
569 memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
570 memcpy(hdr + ETH_ALEN, hdr11->addr4, ETH_ALEN); /* SA */
571 break;
572 case 0:
573 memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
574 memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
575 break;
576 }
577
578 if (stype & IEEE80211_STYPE_QOS_DATA) {
579 const struct ieee80211_hdr_3addrqos *qoshdr =
580 (struct ieee80211_hdr_3addrqos *)skb->data;
581 hdr[12] = le16_to_cpu(qoshdr->qos_ctl) & IEEE80211_QCTL_TID;
582 } else
583 hdr[12] = 0; /* priority */
584
585 hdr[13] = hdr[14] = hdr[15] = 0; /* reserved */
586 }
587
588 static int ieee80211_michael_mic_add(struct sk_buff *skb, int hdr_len,
589 void *priv)
590 {
591 struct ieee80211_tkip_data *tkey = priv;
592 u8 *pos;
593
594 if (skb_tailroom(skb) < 8 || skb->len < hdr_len) {
595 printk(KERN_DEBUG "Invalid packet for Michael MIC add "
596 "(tailroom=%d hdr_len=%d skb->len=%d)\n",
597 skb_tailroom(skb), hdr_len, skb->len);
598 return -1;
599 }
600
601 michael_mic_hdr(skb, tkey->tx_hdr);
602 pos = skb_put(skb, 8);
603 if (michael_mic(tkey->tx_tfm_michael, &tkey->key[16], tkey->tx_hdr,
604 skb->data + hdr_len, skb->len - 8 - hdr_len, pos))
605 return -1;
606
607 return 0;
608 }
609
610 static void ieee80211_michael_mic_failure(struct net_device *dev,
611 struct ieee80211_hdr_4addr *hdr,
612 int keyidx)
613 {
614 union iwreq_data wrqu;
615 struct iw_michaelmicfailure ev;
616
617 /* TODO: needed parameters: count, keyid, key type, TSC */
618 memset(&ev, 0, sizeof(ev));
619 ev.flags = keyidx & IW_MICFAILURE_KEY_ID;
620 if (hdr->addr1[0] & 0x01)
621 ev.flags |= IW_MICFAILURE_GROUP;
622 else
623 ev.flags |= IW_MICFAILURE_PAIRWISE;
624 ev.src_addr.sa_family = ARPHRD_ETHER;
625 memcpy(ev.src_addr.sa_data, hdr->addr2, ETH_ALEN);
626 memset(&wrqu, 0, sizeof(wrqu));
627 wrqu.data.length = sizeof(ev);
628 wireless_send_event(dev, IWEVMICHAELMICFAILURE, &wrqu, (char *)&ev);
629 }
630
631 static int ieee80211_michael_mic_verify(struct sk_buff *skb, int keyidx,
632 int hdr_len, void *priv)
633 {
634 struct ieee80211_tkip_data *tkey = priv;
635 u8 mic[8];
636 DECLARE_MAC_BUF(mac);
637
638 if (!tkey->key_set)
639 return -1;
640
641 michael_mic_hdr(skb, tkey->rx_hdr);
642 if (michael_mic(tkey->rx_tfm_michael, &tkey->key[24], tkey->rx_hdr,
643 skb->data + hdr_len, skb->len - 8 - hdr_len, mic))
644 return -1;
645 if (memcmp(mic, skb->data + skb->len - 8, 8) != 0) {
646 struct ieee80211_hdr_4addr *hdr;
647 hdr = (struct ieee80211_hdr_4addr *)skb->data;
648 printk(KERN_DEBUG "%s: Michael MIC verification failed for "
649 "MSDU from %s keyidx=%d\n",
650 skb->dev ? skb->dev->name : "N/A", print_mac(mac, hdr->addr2),
651 keyidx);
652 if (skb->dev)
653 ieee80211_michael_mic_failure(skb->dev, hdr, keyidx);
654 tkey->dot11RSNAStatsTKIPLocalMICFailures++;
655 return -1;
656 }
657
658 /* Update TSC counters for RX now that the packet verification has
659 * completed. */
660 tkey->rx_iv32 = tkey->rx_iv32_new;
661 tkey->rx_iv16 = tkey->rx_iv16_new;
662
663 skb_trim(skb, skb->len - 8);
664
665 return 0;
666 }
667
668 static int ieee80211_tkip_set_key(void *key, int len, u8 * seq, void *priv)
669 {
670 struct ieee80211_tkip_data *tkey = priv;
671 int keyidx;
672 struct crypto_hash *tfm = tkey->tx_tfm_michael;
673 struct crypto_blkcipher *tfm2 = tkey->tx_tfm_arc4;
674 struct crypto_hash *tfm3 = tkey->rx_tfm_michael;
675 struct crypto_blkcipher *tfm4 = tkey->rx_tfm_arc4;
676
677 keyidx = tkey->key_idx;
678 memset(tkey, 0, sizeof(*tkey));
679 tkey->key_idx = keyidx;
680 tkey->tx_tfm_michael = tfm;
681 tkey->tx_tfm_arc4 = tfm2;
682 tkey->rx_tfm_michael = tfm3;
683 tkey->rx_tfm_arc4 = tfm4;
684 if (len == TKIP_KEY_LEN) {
685 memcpy(tkey->key, key, TKIP_KEY_LEN);
686 tkey->key_set = 1;
687 tkey->tx_iv16 = 1; /* TSC is initialized to 1 */
688 if (seq) {
689 tkey->rx_iv32 = (seq[5] << 24) | (seq[4] << 16) |
690 (seq[3] << 8) | seq[2];
691 tkey->rx_iv16 = (seq[1] << 8) | seq[0];
692 }
693 } else if (len == 0)
694 tkey->key_set = 0;
695 else
696 return -1;
697
698 return 0;
699 }
700
701 static int ieee80211_tkip_get_key(void *key, int len, u8 * seq, void *priv)
702 {
703 struct ieee80211_tkip_data *tkey = priv;
704
705 if (len < TKIP_KEY_LEN)
706 return -1;
707
708 if (!tkey->key_set)
709 return 0;
710 memcpy(key, tkey->key, TKIP_KEY_LEN);
711
712 if (seq) {
713 /* Return the sequence number of the last transmitted frame. */
714 u16 iv16 = tkey->tx_iv16;
715 u32 iv32 = tkey->tx_iv32;
716 if (iv16 == 0)
717 iv32--;
718 iv16--;
719 seq[0] = tkey->tx_iv16;
720 seq[1] = tkey->tx_iv16 >> 8;
721 seq[2] = tkey->tx_iv32;
722 seq[3] = tkey->tx_iv32 >> 8;
723 seq[4] = tkey->tx_iv32 >> 16;
724 seq[5] = tkey->tx_iv32 >> 24;
725 }
726
727 return TKIP_KEY_LEN;
728 }
729
730 static char *ieee80211_tkip_print_stats(char *p, void *priv)
731 {
732 struct ieee80211_tkip_data *tkip = priv;
733 p += sprintf(p, "key[%d] alg=TKIP key_set=%d "
734 "tx_pn=%02x%02x%02x%02x%02x%02x "
735 "rx_pn=%02x%02x%02x%02x%02x%02x "
736 "replays=%d icv_errors=%d local_mic_failures=%d\n",
737 tkip->key_idx, tkip->key_set,
738 (tkip->tx_iv32 >> 24) & 0xff,
739 (tkip->tx_iv32 >> 16) & 0xff,
740 (tkip->tx_iv32 >> 8) & 0xff,
741 tkip->tx_iv32 & 0xff,
742 (tkip->tx_iv16 >> 8) & 0xff,
743 tkip->tx_iv16 & 0xff,
744 (tkip->rx_iv32 >> 24) & 0xff,
745 (tkip->rx_iv32 >> 16) & 0xff,
746 (tkip->rx_iv32 >> 8) & 0xff,
747 tkip->rx_iv32 & 0xff,
748 (tkip->rx_iv16 >> 8) & 0xff,
749 tkip->rx_iv16 & 0xff,
750 tkip->dot11RSNAStatsTKIPReplays,
751 tkip->dot11RSNAStatsTKIPICVErrors,
752 tkip->dot11RSNAStatsTKIPLocalMICFailures);
753 return p;
754 }
755
756 static struct ieee80211_crypto_ops ieee80211_crypt_tkip = {
757 .name = "TKIP",
758 .init = ieee80211_tkip_init,
759 .deinit = ieee80211_tkip_deinit,
760 .build_iv = ieee80211_tkip_hdr,
761 .encrypt_mpdu = ieee80211_tkip_encrypt,
762 .decrypt_mpdu = ieee80211_tkip_decrypt,
763 .encrypt_msdu = ieee80211_michael_mic_add,
764 .decrypt_msdu = ieee80211_michael_mic_verify,
765 .set_key = ieee80211_tkip_set_key,
766 .get_key = ieee80211_tkip_get_key,
767 .print_stats = ieee80211_tkip_print_stats,
768 .extra_mpdu_prefix_len = 4 + 4, /* IV + ExtIV */
769 .extra_mpdu_postfix_len = 4, /* ICV */
770 .extra_msdu_postfix_len = 8, /* MIC */
771 .get_flags = ieee80211_tkip_get_flags,
772 .set_flags = ieee80211_tkip_set_flags,
773 .owner = THIS_MODULE,
774 };
775
776 static int __init ieee80211_crypto_tkip_init(void)
777 {
778 return ieee80211_register_crypto_ops(&ieee80211_crypt_tkip);
779 }
780
781 static void __exit ieee80211_crypto_tkip_exit(void)
782 {
783 ieee80211_unregister_crypto_ops(&ieee80211_crypt_tkip);
784 }
785
786 module_init(ieee80211_crypto_tkip_init);
787 module_exit(ieee80211_crypto_tkip_exit);
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