ieee80211_crypt_tkip.c 21 KB

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  1. /*
  2. * Host AP crypt: host-based TKIP encryption implementation for Host AP driver
  3. *
  4. * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.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. #include <linux/err.h>
  12. #include <linux/module.h>
  13. #include <linux/init.h>
  14. #include <linux/slab.h>
  15. #include <linux/random.h>
  16. #include <linux/skbuff.h>
  17. #include <linux/netdevice.h>
  18. #include <linux/mm.h>
  19. #include <linux/if_ether.h>
  20. #include <linux/if_arp.h>
  21. #include <asm/string.h>
  22. #include <net/ieee80211.h>
  23. #include <linux/crypto.h>
  24. #include <asm/scatterlist.h>
  25. #include <linux/crc32.h>
  26. MODULE_AUTHOR("Jouni Malinen");
  27. MODULE_DESCRIPTION("Host AP crypt: TKIP");
  28. MODULE_LICENSE("GPL");
  29. struct ieee80211_tkip_data {
  30. #define TKIP_KEY_LEN 32
  31. u8 key[TKIP_KEY_LEN];
  32. int key_set;
  33. u32 tx_iv32;
  34. u16 tx_iv16;
  35. u16 tx_ttak[5];
  36. int tx_phase1_done;
  37. u32 rx_iv32;
  38. u16 rx_iv16;
  39. u16 rx_ttak[5];
  40. int rx_phase1_done;
  41. u32 rx_iv32_new;
  42. u16 rx_iv16_new;
  43. u32 dot11RSNAStatsTKIPReplays;
  44. u32 dot11RSNAStatsTKIPICVErrors;
  45. u32 dot11RSNAStatsTKIPLocalMICFailures;
  46. int key_idx;
  47. struct crypto_blkcipher *rx_tfm_arc4;
  48. struct crypto_hash *rx_tfm_michael;
  49. struct crypto_blkcipher *tx_tfm_arc4;
  50. struct crypto_hash *tx_tfm_michael;
  51. /* scratch buffers for virt_to_page() (crypto API) */
  52. u8 rx_hdr[16], tx_hdr[16];
  53. unsigned long flags;
  54. };
  55. static unsigned long ieee80211_tkip_set_flags(unsigned long flags, void *priv)
  56. {
  57. struct ieee80211_tkip_data *_priv = priv;
  58. unsigned long old_flags = _priv->flags;
  59. _priv->flags = flags;
  60. return old_flags;
  61. }
  62. static unsigned long ieee80211_tkip_get_flags(void *priv)
  63. {
  64. struct ieee80211_tkip_data *_priv = priv;
  65. return _priv->flags;
  66. }
  67. static void *ieee80211_tkip_init(int key_idx)
  68. {
  69. struct ieee80211_tkip_data *priv;
  70. priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
  71. if (priv == NULL)
  72. goto fail;
  73. priv->key_idx = key_idx;
  74. priv->tx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
  75. CRYPTO_ALG_ASYNC);
  76. if (IS_ERR(priv->tx_tfm_arc4)) {
  77. printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
  78. "crypto API arc4\n");
  79. priv->tx_tfm_arc4 = NULL;
  80. goto fail;
  81. }
  82. priv->tx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
  83. CRYPTO_ALG_ASYNC);
  84. if (IS_ERR(priv->tx_tfm_michael)) {
  85. printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
  86. "crypto API michael_mic\n");
  87. priv->tx_tfm_michael = NULL;
  88. goto fail;
  89. }
  90. priv->rx_tfm_arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0,
  91. CRYPTO_ALG_ASYNC);
  92. if (IS_ERR(priv->rx_tfm_arc4)) {
  93. printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
  94. "crypto API arc4\n");
  95. priv->rx_tfm_arc4 = NULL;
  96. goto fail;
  97. }
  98. priv->rx_tfm_michael = crypto_alloc_hash("michael_mic", 0,
  99. CRYPTO_ALG_ASYNC);
  100. if (IS_ERR(priv->rx_tfm_michael)) {
  101. printk(KERN_DEBUG "ieee80211_crypt_tkip: could not allocate "
  102. "crypto API michael_mic\n");
  103. priv->rx_tfm_michael = NULL;
  104. goto fail;
  105. }
  106. return priv;
  107. fail:
  108. if (priv) {
  109. if (priv->tx_tfm_michael)
  110. crypto_free_hash(priv->tx_tfm_michael);
  111. if (priv->tx_tfm_arc4)
  112. crypto_free_blkcipher(priv->tx_tfm_arc4);
  113. if (priv->rx_tfm_michael)
  114. crypto_free_hash(priv->rx_tfm_michael);
  115. if (priv->rx_tfm_arc4)
  116. crypto_free_blkcipher(priv->rx_tfm_arc4);
  117. kfree(priv);
  118. }
  119. return NULL;
  120. }
  121. static void ieee80211_tkip_deinit(void *priv)
  122. {
  123. struct ieee80211_tkip_data *_priv = priv;
  124. if (_priv) {
  125. if (_priv->tx_tfm_michael)
  126. crypto_free_hash(_priv->tx_tfm_michael);
  127. if (_priv->tx_tfm_arc4)
  128. crypto_free_blkcipher(_priv->tx_tfm_arc4);
  129. if (_priv->rx_tfm_michael)
  130. crypto_free_hash(_priv->rx_tfm_michael);
  131. if (_priv->rx_tfm_arc4)
  132. crypto_free_blkcipher(_priv->rx_tfm_arc4);
  133. }
  134. kfree(priv);
  135. }
  136. static inline u16 RotR1(u16 val)
  137. {
  138. return (val >> 1) | (val << 15);
  139. }
  140. static inline u8 Lo8(u16 val)
  141. {
  142. return val & 0xff;
  143. }
  144. static inline u8 Hi8(u16 val)
  145. {
  146. return val >> 8;
  147. }
  148. static inline u16 Lo16(u32 val)
  149. {
  150. return val & 0xffff;
  151. }
  152. static inline u16 Hi16(u32 val)
  153. {
  154. return val >> 16;
  155. }
  156. static inline u16 Mk16(u8 hi, u8 lo)
  157. {
  158. return lo | (((u16) hi) << 8);
  159. }
  160. static inline u16 Mk16_le(u16 * v)
  161. {
  162. return le16_to_cpu(*v);
  163. }
  164. static const u16 Sbox[256] = {
  165. 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
  166. 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
  167. 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
  168. 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
  169. 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
  170. 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
  171. 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
  172. 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
  173. 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
  174. 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
  175. 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
  176. 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
  177. 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
  178. 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
  179. 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
  180. 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
  181. 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
  182. 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
  183. 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
  184. 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
  185. 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
  186. 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
  187. 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
  188. 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
  189. 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
  190. 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
  191. 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
  192. 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
  193. 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
  194. 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
  195. 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
  196. 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
  197. };
  198. static inline u16 _S_(u16 v)
  199. {
  200. u16 t = Sbox[Hi8(v)];
  201. return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
  202. }
  203. #define PHASE1_LOOP_COUNT 8
  204. static void tkip_mixing_phase1(u16 * TTAK, const u8 * TK, const u8 * TA,
  205. u32 IV32)
  206. {
  207. int i, j;
  208. /* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
  209. TTAK[0] = Lo16(IV32);
  210. TTAK[1] = Hi16(IV32);
  211. TTAK[2] = Mk16(TA[1], TA[0]);
  212. TTAK[3] = Mk16(TA[3], TA[2]);
  213. TTAK[4] = Mk16(TA[5], TA[4]);
  214. for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
  215. j = 2 * (i & 1);
  216. TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
  217. TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
  218. TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
  219. TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
  220. TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
  221. }
  222. }
  223. static void tkip_mixing_phase2(u8 * WEPSeed, const u8 * TK, const u16 * TTAK,
  224. u16 IV16)
  225. {
  226. /* Make temporary area overlap WEP seed so that the final copy can be
  227. * avoided on little endian hosts. */
  228. u16 *PPK = (u16 *) & WEPSeed[4];
  229. /* Step 1 - make copy of TTAK and bring in TSC */
  230. PPK[0] = TTAK[0];
  231. PPK[1] = TTAK[1];
  232. PPK[2] = TTAK[2];
  233. PPK[3] = TTAK[3];
  234. PPK[4] = TTAK[4];
  235. PPK[5] = TTAK[4] + IV16;
  236. /* Step 2 - 96-bit bijective mixing using S-box */
  237. PPK[0] += _S_(PPK[5] ^ Mk16_le((u16 *) & TK[0]));
  238. PPK[1] += _S_(PPK[0] ^ Mk16_le((u16 *) & TK[2]));
  239. PPK[2] += _S_(PPK[1] ^ Mk16_le((u16 *) & TK[4]));
  240. PPK[3] += _S_(PPK[2] ^ Mk16_le((u16 *) & TK[6]));
  241. PPK[4] += _S_(PPK[3] ^ Mk16_le((u16 *) & TK[8]));
  242. PPK[5] += _S_(PPK[4] ^ Mk16_le((u16 *) & TK[10]));
  243. PPK[0] += RotR1(PPK[5] ^ Mk16_le((u16 *) & TK[12]));
  244. PPK[1] += RotR1(PPK[0] ^ Mk16_le((u16 *) & TK[14]));
  245. PPK[2] += RotR1(PPK[1]);
  246. PPK[3] += RotR1(PPK[2]);
  247. PPK[4] += RotR1(PPK[3]);
  248. PPK[5] += RotR1(PPK[4]);
  249. /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
  250. * WEPSeed[0..2] is transmitted as WEP IV */
  251. WEPSeed[0] = Hi8(IV16);
  252. WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
  253. WEPSeed[2] = Lo8(IV16);
  254. WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((u16 *) & TK[0])) >> 1);
  255. #ifdef __BIG_ENDIAN
  256. {
  257. int i;
  258. for (i = 0; i < 6; i++)
  259. PPK[i] = (PPK[i] << 8) | (PPK[i] >> 8);
  260. }
  261. #endif
  262. }
  263. static int ieee80211_tkip_hdr(struct sk_buff *skb, int hdr_len,
  264. u8 * rc4key, int keylen, void *priv)
  265. {
  266. struct ieee80211_tkip_data *tkey = priv;
  267. int len;
  268. u8 *pos;
  269. struct ieee80211_hdr_4addr *hdr;
  270. hdr = (struct ieee80211_hdr_4addr *)skb->data;
  271. if (skb_headroom(skb) < 8 || skb->len < hdr_len)
  272. return -1;
  273. if (rc4key == NULL || keylen < 16)
  274. return -1;
  275. if (!tkey->tx_phase1_done) {
  276. tkip_mixing_phase1(tkey->tx_ttak, tkey->key, hdr->addr2,
  277. tkey->tx_iv32);
  278. tkey->tx_phase1_done = 1;
  279. }
  280. tkip_mixing_phase2(rc4key, tkey->key, tkey->tx_ttak, tkey->tx_iv16);
  281. len = skb->len - hdr_len;
  282. pos = skb_push(skb, 8);
  283. memmove(pos, pos + 8, hdr_len);
  284. pos += hdr_len;
  285. *pos++ = *rc4key;
  286. *pos++ = *(rc4key + 1);
  287. *pos++ = *(rc4key + 2);
  288. *pos++ = (tkey->key_idx << 6) | (1 << 5) /* Ext IV included */ ;
  289. *pos++ = tkey->tx_iv32 & 0xff;
  290. *pos++ = (tkey->tx_iv32 >> 8) & 0xff;
  291. *pos++ = (tkey->tx_iv32 >> 16) & 0xff;
  292. *pos++ = (tkey->tx_iv32 >> 24) & 0xff;
  293. tkey->tx_iv16++;
  294. if (tkey->tx_iv16 == 0) {
  295. tkey->tx_phase1_done = 0;
  296. tkey->tx_iv32++;
  297. }
  298. return 8;
  299. }
  300. static int ieee80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
  301. {
  302. struct ieee80211_tkip_data *tkey = priv;
  303. struct blkcipher_desc desc = { .tfm = tkey->tx_tfm_arc4 };
  304. int len;
  305. u8 rc4key[16], *pos, *icv;
  306. u32 crc;
  307. struct scatterlist sg;
  308. if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
  309. if (net_ratelimit()) {
  310. struct ieee80211_hdr_4addr *hdr =
  311. (struct ieee80211_hdr_4addr *)skb->data;
  312. printk(KERN_DEBUG ": TKIP countermeasures: dropped "
  313. "TX packet to " MAC_FMT "\n",
  314. MAC_ARG(hdr->addr1));
  315. }
  316. return -1;
  317. }
  318. if (skb_tailroom(skb) < 4 || skb->len < hdr_len)
  319. return -1;
  320. len = skb->len - hdr_len;
  321. pos = skb->data + hdr_len;
  322. if ((ieee80211_tkip_hdr(skb, hdr_len, rc4key, 16, priv)) < 0)
  323. return -1;
  324. icv = skb_put(skb, 4);
  325. crc = ~crc32_le(~0, pos, len);
  326. icv[0] = crc;
  327. icv[1] = crc >> 8;
  328. icv[2] = crc >> 16;
  329. icv[3] = crc >> 24;
  330. crypto_blkcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);
  331. sg.page = virt_to_page(pos);
  332. sg.offset = offset_in_page(pos);
  333. sg.length = len + 4;
  334. return crypto_blkcipher_encrypt(&desc, &sg, &sg, len + 4);
  335. }
  336. /*
  337. * deal with seq counter wrapping correctly.
  338. * refer to timer_after() for jiffies wrapping handling
  339. */
  340. static inline int tkip_replay_check(u32 iv32_n, u16 iv16_n,
  341. u32 iv32_o, u16 iv16_o)
  342. {
  343. if ((s32)iv32_n - (s32)iv32_o < 0 ||
  344. (iv32_n == iv32_o && iv16_n <= iv16_o))
  345. return 1;
  346. return 0;
  347. }
  348. static int ieee80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
  349. {
  350. struct ieee80211_tkip_data *tkey = priv;
  351. struct blkcipher_desc desc = { .tfm = tkey->rx_tfm_arc4 };
  352. u8 rc4key[16];
  353. u8 keyidx, *pos;
  354. u32 iv32;
  355. u16 iv16;
  356. struct ieee80211_hdr_4addr *hdr;
  357. u8 icv[4];
  358. u32 crc;
  359. struct scatterlist sg;
  360. int plen;
  361. hdr = (struct ieee80211_hdr_4addr *)skb->data;
  362. if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
  363. if (net_ratelimit()) {
  364. printk(KERN_DEBUG ": TKIP countermeasures: dropped "
  365. "received packet from " MAC_FMT "\n",
  366. MAC_ARG(hdr->addr2));
  367. }
  368. return -1;
  369. }
  370. if (skb->len < hdr_len + 8 + 4)
  371. return -1;
  372. pos = skb->data + hdr_len;
  373. keyidx = pos[3];
  374. if (!(keyidx & (1 << 5))) {
  375. if (net_ratelimit()) {
  376. printk(KERN_DEBUG "TKIP: received packet without ExtIV"
  377. " flag from " MAC_FMT "\n", MAC_ARG(hdr->addr2));
  378. }
  379. return -2;
  380. }
  381. keyidx >>= 6;
  382. if (tkey->key_idx != keyidx) {
  383. printk(KERN_DEBUG "TKIP: RX tkey->key_idx=%d frame "
  384. "keyidx=%d priv=%p\n", tkey->key_idx, keyidx, priv);
  385. return -6;
  386. }
  387. if (!tkey->key_set) {
  388. if (net_ratelimit()) {
  389. printk(KERN_DEBUG "TKIP: received packet from " MAC_FMT
  390. " with keyid=%d that does not have a configured"
  391. " key\n", MAC_ARG(hdr->addr2), keyidx);
  392. }
  393. return -3;
  394. }
  395. iv16 = (pos[0] << 8) | pos[2];
  396. iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24);
  397. pos += 8;
  398. if (tkip_replay_check(iv32, iv16, tkey->rx_iv32, tkey->rx_iv16)) {
  399. if (net_ratelimit()) {
  400. printk(KERN_DEBUG "TKIP: replay detected: STA=" MAC_FMT
  401. " previous TSC %08x%04x received TSC "
  402. "%08x%04x\n", MAC_ARG(hdr->addr2),
  403. tkey->rx_iv32, tkey->rx_iv16, iv32, iv16);
  404. }
  405. tkey->dot11RSNAStatsTKIPReplays++;
  406. return -4;
  407. }
  408. if (iv32 != tkey->rx_iv32 || !tkey->rx_phase1_done) {
  409. tkip_mixing_phase1(tkey->rx_ttak, tkey->key, hdr->addr2, iv32);
  410. tkey->rx_phase1_done = 1;
  411. }
  412. tkip_mixing_phase2(rc4key, tkey->key, tkey->rx_ttak, iv16);
  413. plen = skb->len - hdr_len - 12;
  414. crypto_blkcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);
  415. sg.page = virt_to_page(pos);
  416. sg.offset = offset_in_page(pos);
  417. sg.length = plen + 4;
  418. if (crypto_blkcipher_decrypt(&desc, &sg, &sg, plen + 4)) {
  419. if (net_ratelimit()) {
  420. printk(KERN_DEBUG ": TKIP: failed to decrypt "
  421. "received packet from " MAC_FMT "\n",
  422. MAC_ARG(hdr->addr2));
  423. }
  424. return -7;
  425. }
  426. crc = ~crc32_le(~0, pos, plen);
  427. icv[0] = crc;
  428. icv[1] = crc >> 8;
  429. icv[2] = crc >> 16;
  430. icv[3] = crc >> 24;
  431. if (memcmp(icv, pos + plen, 4) != 0) {
  432. if (iv32 != tkey->rx_iv32) {
  433. /* Previously cached Phase1 result was already lost, so
  434. * it needs to be recalculated for the next packet. */
  435. tkey->rx_phase1_done = 0;
  436. }
  437. if (net_ratelimit()) {
  438. printk(KERN_DEBUG "TKIP: ICV error detected: STA="
  439. MAC_FMT "\n", MAC_ARG(hdr->addr2));
  440. }
  441. tkey->dot11RSNAStatsTKIPICVErrors++;
  442. return -5;
  443. }
  444. /* Update real counters only after Michael MIC verification has
  445. * completed */
  446. tkey->rx_iv32_new = iv32;
  447. tkey->rx_iv16_new = iv16;
  448. /* Remove IV and ICV */
  449. memmove(skb->data + 8, skb->data, hdr_len);
  450. skb_pull(skb, 8);
  451. skb_trim(skb, skb->len - 4);
  452. return keyidx;
  453. }
  454. static int michael_mic(struct crypto_hash *tfm_michael, u8 * key, u8 * hdr,
  455. u8 * data, size_t data_len, u8 * mic)
  456. {
  457. struct hash_desc desc;
  458. struct scatterlist sg[2];
  459. if (tfm_michael == NULL) {
  460. printk(KERN_WARNING "michael_mic: tfm_michael == NULL\n");
  461. return -1;
  462. }
  463. sg[0].page = virt_to_page(hdr);
  464. sg[0].offset = offset_in_page(hdr);
  465. sg[0].length = 16;
  466. sg[1].page = virt_to_page(data);
  467. sg[1].offset = offset_in_page(data);
  468. sg[1].length = data_len;
  469. if (crypto_hash_setkey(tfm_michael, key, 8))
  470. return -1;
  471. desc.tfm = tfm_michael;
  472. desc.flags = 0;
  473. return crypto_hash_digest(&desc, sg, data_len + 16, mic);
  474. }
  475. static void michael_mic_hdr(struct sk_buff *skb, u8 * hdr)
  476. {
  477. struct ieee80211_hdr_4addr *hdr11;
  478. u16 stype;
  479. hdr11 = (struct ieee80211_hdr_4addr *)skb->data;
  480. stype = WLAN_FC_GET_STYPE(le16_to_cpu(hdr11->frame_ctl));
  481. switch (le16_to_cpu(hdr11->frame_ctl) &
  482. (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
  483. case IEEE80211_FCTL_TODS:
  484. memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
  485. memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
  486. break;
  487. case IEEE80211_FCTL_FROMDS:
  488. memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
  489. memcpy(hdr + ETH_ALEN, hdr11->addr3, ETH_ALEN); /* SA */
  490. break;
  491. case IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS:
  492. memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
  493. memcpy(hdr + ETH_ALEN, hdr11->addr4, ETH_ALEN); /* SA */
  494. break;
  495. case 0:
  496. memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
  497. memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
  498. break;
  499. }
  500. if (stype & IEEE80211_STYPE_QOS_DATA) {
  501. const struct ieee80211_hdr_3addrqos *qoshdr =
  502. (struct ieee80211_hdr_3addrqos *)skb->data;
  503. hdr[12] = qoshdr->qos_ctl & cpu_to_le16(IEEE80211_QCTL_TID);
  504. } else
  505. hdr[12] = 0; /* priority */
  506. hdr[13] = hdr[14] = hdr[15] = 0; /* reserved */
  507. }
  508. static int ieee80211_michael_mic_add(struct sk_buff *skb, int hdr_len,
  509. void *priv)
  510. {
  511. struct ieee80211_tkip_data *tkey = priv;
  512. u8 *pos;
  513. if (skb_tailroom(skb) < 8 || skb->len < hdr_len) {
  514. printk(KERN_DEBUG "Invalid packet for Michael MIC add "
  515. "(tailroom=%d hdr_len=%d skb->len=%d)\n",
  516. skb_tailroom(skb), hdr_len, skb->len);
  517. return -1;
  518. }
  519. michael_mic_hdr(skb, tkey->tx_hdr);
  520. pos = skb_put(skb, 8);
  521. if (michael_mic(tkey->tx_tfm_michael, &tkey->key[16], tkey->tx_hdr,
  522. skb->data + hdr_len, skb->len - 8 - hdr_len, pos))
  523. return -1;
  524. return 0;
  525. }
  526. static void ieee80211_michael_mic_failure(struct net_device *dev,
  527. struct ieee80211_hdr_4addr *hdr,
  528. int keyidx)
  529. {
  530. union iwreq_data wrqu;
  531. struct iw_michaelmicfailure ev;
  532. /* TODO: needed parameters: count, keyid, key type, TSC */
  533. memset(&ev, 0, sizeof(ev));
  534. ev.flags = keyidx & IW_MICFAILURE_KEY_ID;
  535. if (hdr->addr1[0] & 0x01)
  536. ev.flags |= IW_MICFAILURE_GROUP;
  537. else
  538. ev.flags |= IW_MICFAILURE_PAIRWISE;
  539. ev.src_addr.sa_family = ARPHRD_ETHER;
  540. memcpy(ev.src_addr.sa_data, hdr->addr2, ETH_ALEN);
  541. memset(&wrqu, 0, sizeof(wrqu));
  542. wrqu.data.length = sizeof(ev);
  543. wireless_send_event(dev, IWEVMICHAELMICFAILURE, &wrqu, (char *)&ev);
  544. }
  545. static int ieee80211_michael_mic_verify(struct sk_buff *skb, int keyidx,
  546. int hdr_len, void *priv)
  547. {
  548. struct ieee80211_tkip_data *tkey = priv;
  549. u8 mic[8];
  550. if (!tkey->key_set)
  551. return -1;
  552. michael_mic_hdr(skb, tkey->rx_hdr);
  553. if (michael_mic(tkey->rx_tfm_michael, &tkey->key[24], tkey->rx_hdr,
  554. skb->data + hdr_len, skb->len - 8 - hdr_len, mic))
  555. return -1;
  556. if (memcmp(mic, skb->data + skb->len - 8, 8) != 0) {
  557. struct ieee80211_hdr_4addr *hdr;
  558. hdr = (struct ieee80211_hdr_4addr *)skb->data;
  559. printk(KERN_DEBUG "%s: Michael MIC verification failed for "
  560. "MSDU from " MAC_FMT " keyidx=%d\n",
  561. skb->dev ? skb->dev->name : "N/A", MAC_ARG(hdr->addr2),
  562. keyidx);
  563. if (skb->dev)
  564. ieee80211_michael_mic_failure(skb->dev, hdr, keyidx);
  565. tkey->dot11RSNAStatsTKIPLocalMICFailures++;
  566. return -1;
  567. }
  568. /* Update TSC counters for RX now that the packet verification has
  569. * completed. */
  570. tkey->rx_iv32 = tkey->rx_iv32_new;
  571. tkey->rx_iv16 = tkey->rx_iv16_new;
  572. skb_trim(skb, skb->len - 8);
  573. return 0;
  574. }
  575. static int ieee80211_tkip_set_key(void *key, int len, u8 * seq, void *priv)
  576. {
  577. struct ieee80211_tkip_data *tkey = priv;
  578. int keyidx;
  579. struct crypto_hash *tfm = tkey->tx_tfm_michael;
  580. struct crypto_blkcipher *tfm2 = tkey->tx_tfm_arc4;
  581. struct crypto_hash *tfm3 = tkey->rx_tfm_michael;
  582. struct crypto_blkcipher *tfm4 = tkey->rx_tfm_arc4;
  583. keyidx = tkey->key_idx;
  584. memset(tkey, 0, sizeof(*tkey));
  585. tkey->key_idx = keyidx;
  586. tkey->tx_tfm_michael = tfm;
  587. tkey->tx_tfm_arc4 = tfm2;
  588. tkey->rx_tfm_michael = tfm3;
  589. tkey->rx_tfm_arc4 = tfm4;
  590. if (len == TKIP_KEY_LEN) {
  591. memcpy(tkey->key, key, TKIP_KEY_LEN);
  592. tkey->key_set = 1;
  593. tkey->tx_iv16 = 1; /* TSC is initialized to 1 */
  594. if (seq) {
  595. tkey->rx_iv32 = (seq[5] << 24) | (seq[4] << 16) |
  596. (seq[3] << 8) | seq[2];
  597. tkey->rx_iv16 = (seq[1] << 8) | seq[0];
  598. }
  599. } else if (len == 0)
  600. tkey->key_set = 0;
  601. else
  602. return -1;
  603. return 0;
  604. }
  605. static int ieee80211_tkip_get_key(void *key, int len, u8 * seq, void *priv)
  606. {
  607. struct ieee80211_tkip_data *tkey = priv;
  608. if (len < TKIP_KEY_LEN)
  609. return -1;
  610. if (!tkey->key_set)
  611. return 0;
  612. memcpy(key, tkey->key, TKIP_KEY_LEN);
  613. if (seq) {
  614. /* Return the sequence number of the last transmitted frame. */
  615. u16 iv16 = tkey->tx_iv16;
  616. u32 iv32 = tkey->tx_iv32;
  617. if (iv16 == 0)
  618. iv32--;
  619. iv16--;
  620. seq[0] = tkey->tx_iv16;
  621. seq[1] = tkey->tx_iv16 >> 8;
  622. seq[2] = tkey->tx_iv32;
  623. seq[3] = tkey->tx_iv32 >> 8;
  624. seq[4] = tkey->tx_iv32 >> 16;
  625. seq[5] = tkey->tx_iv32 >> 24;
  626. }
  627. return TKIP_KEY_LEN;
  628. }
  629. static char *ieee80211_tkip_print_stats(char *p, void *priv)
  630. {
  631. struct ieee80211_tkip_data *tkip = priv;
  632. p += sprintf(p, "key[%d] alg=TKIP key_set=%d "
  633. "tx_pn=%02x%02x%02x%02x%02x%02x "
  634. "rx_pn=%02x%02x%02x%02x%02x%02x "
  635. "replays=%d icv_errors=%d local_mic_failures=%d\n",
  636. tkip->key_idx, tkip->key_set,
  637. (tkip->tx_iv32 >> 24) & 0xff,
  638. (tkip->tx_iv32 >> 16) & 0xff,
  639. (tkip->tx_iv32 >> 8) & 0xff,
  640. tkip->tx_iv32 & 0xff,
  641. (tkip->tx_iv16 >> 8) & 0xff,
  642. tkip->tx_iv16 & 0xff,
  643. (tkip->rx_iv32 >> 24) & 0xff,
  644. (tkip->rx_iv32 >> 16) & 0xff,
  645. (tkip->rx_iv32 >> 8) & 0xff,
  646. tkip->rx_iv32 & 0xff,
  647. (tkip->rx_iv16 >> 8) & 0xff,
  648. tkip->rx_iv16 & 0xff,
  649. tkip->dot11RSNAStatsTKIPReplays,
  650. tkip->dot11RSNAStatsTKIPICVErrors,
  651. tkip->dot11RSNAStatsTKIPLocalMICFailures);
  652. return p;
  653. }
  654. static struct ieee80211_crypto_ops ieee80211_crypt_tkip = {
  655. .name = "TKIP",
  656. .init = ieee80211_tkip_init,
  657. .deinit = ieee80211_tkip_deinit,
  658. .build_iv = ieee80211_tkip_hdr,
  659. .encrypt_mpdu = ieee80211_tkip_encrypt,
  660. .decrypt_mpdu = ieee80211_tkip_decrypt,
  661. .encrypt_msdu = ieee80211_michael_mic_add,
  662. .decrypt_msdu = ieee80211_michael_mic_verify,
  663. .set_key = ieee80211_tkip_set_key,
  664. .get_key = ieee80211_tkip_get_key,
  665. .print_stats = ieee80211_tkip_print_stats,
  666. .extra_mpdu_prefix_len = 4 + 4, /* IV + ExtIV */
  667. .extra_mpdu_postfix_len = 4, /* ICV */
  668. .extra_msdu_postfix_len = 8, /* MIC */
  669. .get_flags = ieee80211_tkip_get_flags,
  670. .set_flags = ieee80211_tkip_set_flags,
  671. .owner = THIS_MODULE,
  672. };
  673. static int __init ieee80211_crypto_tkip_init(void)
  674. {
  675. return ieee80211_register_crypto_ops(&ieee80211_crypt_tkip);
  676. }
  677. static void __exit ieee80211_crypto_tkip_exit(void)
  678. {
  679. ieee80211_unregister_crypto_ops(&ieee80211_crypt_tkip);
  680. }
  681. module_init(ieee80211_crypto_tkip_init);
  682. module_exit(ieee80211_crypto_tkip_exit);