lib80211_crypt_tkip.c 21 KB

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  1. /*
  2. * lib80211 crypt: host-based TKIP encryption implementation for lib80211
  3. *
  4. * Copyright (c) 2003-2004, Jouni Malinen <j@w1.fi>
  5. * Copyright (c) 2008, John W. Linville <linville@tuxdriver.com>
  6. *
  7. * This program is free software; you can redistribute it and/or modify
  8. * it under the terms of the GNU General Public License version 2 as
  9. * published by the Free Software Foundation. See README and COPYING for
  10. * more details.
  11. */
  12. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13. #include <linux/err.h>
  14. #include <linux/module.h>
  15. #include <linux/init.h>
  16. #include <linux/slab.h>
  17. #include <linux/random.h>
  18. #include <linux/scatterlist.h>
  19. #include <linux/skbuff.h>
  20. #include <linux/netdevice.h>
  21. #include <linux/mm.h>
  22. #include <linux/if_ether.h>
  23. #include <linux/if_arp.h>
  24. #include <asm/string.h>
  25. #include <linux/wireless.h>
  26. #include <linux/ieee80211.h>
  27. #include <net/iw_handler.h>
  28. #include <crypto/hash.h>
  29. #include <crypto/skcipher.h>
  30. #include <linux/crc32.h>
  31. #include <net/lib80211.h>
  32. MODULE_AUTHOR("Jouni Malinen");
  33. MODULE_DESCRIPTION("lib80211 crypt: TKIP");
  34. MODULE_LICENSE("GPL");
  35. #define TKIP_HDR_LEN 8
  36. struct lib80211_tkip_data {
  37. #define TKIP_KEY_LEN 32
  38. u8 key[TKIP_KEY_LEN];
  39. int key_set;
  40. u32 tx_iv32;
  41. u16 tx_iv16;
  42. u16 tx_ttak[5];
  43. int tx_phase1_done;
  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. u32 dot11RSNAStatsTKIPReplays;
  51. u32 dot11RSNAStatsTKIPICVErrors;
  52. u32 dot11RSNAStatsTKIPLocalMICFailures;
  53. int key_idx;
  54. struct crypto_skcipher *rx_tfm_arc4;
  55. struct crypto_ahash *rx_tfm_michael;
  56. struct crypto_skcipher *tx_tfm_arc4;
  57. struct crypto_ahash *tx_tfm_michael;
  58. /* scratch buffers for virt_to_page() (crypto API) */
  59. u8 rx_hdr[16], tx_hdr[16];
  60. unsigned long flags;
  61. };
  62. static unsigned long lib80211_tkip_set_flags(unsigned long flags, void *priv)
  63. {
  64. struct lib80211_tkip_data *_priv = priv;
  65. unsigned long old_flags = _priv->flags;
  66. _priv->flags = flags;
  67. return old_flags;
  68. }
  69. static unsigned long lib80211_tkip_get_flags(void *priv)
  70. {
  71. struct lib80211_tkip_data *_priv = priv;
  72. return _priv->flags;
  73. }
  74. static void *lib80211_tkip_init(int key_idx)
  75. {
  76. struct lib80211_tkip_data *priv;
  77. priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
  78. if (priv == NULL)
  79. goto fail;
  80. priv->key_idx = key_idx;
  81. priv->tx_tfm_arc4 = crypto_alloc_skcipher("ecb(arc4)", 0,
  82. CRYPTO_ALG_ASYNC);
  83. if (IS_ERR(priv->tx_tfm_arc4)) {
  84. priv->tx_tfm_arc4 = NULL;
  85. goto fail;
  86. }
  87. priv->tx_tfm_michael = crypto_alloc_ahash("michael_mic", 0,
  88. CRYPTO_ALG_ASYNC);
  89. if (IS_ERR(priv->tx_tfm_michael)) {
  90. priv->tx_tfm_michael = NULL;
  91. goto fail;
  92. }
  93. priv->rx_tfm_arc4 = crypto_alloc_skcipher("ecb(arc4)", 0,
  94. CRYPTO_ALG_ASYNC);
  95. if (IS_ERR(priv->rx_tfm_arc4)) {
  96. priv->rx_tfm_arc4 = NULL;
  97. goto fail;
  98. }
  99. priv->rx_tfm_michael = crypto_alloc_ahash("michael_mic", 0,
  100. CRYPTO_ALG_ASYNC);
  101. if (IS_ERR(priv->rx_tfm_michael)) {
  102. priv->rx_tfm_michael = NULL;
  103. goto fail;
  104. }
  105. return priv;
  106. fail:
  107. if (priv) {
  108. crypto_free_ahash(priv->tx_tfm_michael);
  109. crypto_free_skcipher(priv->tx_tfm_arc4);
  110. crypto_free_ahash(priv->rx_tfm_michael);
  111. crypto_free_skcipher(priv->rx_tfm_arc4);
  112. kfree(priv);
  113. }
  114. return NULL;
  115. }
  116. static void lib80211_tkip_deinit(void *priv)
  117. {
  118. struct lib80211_tkip_data *_priv = priv;
  119. if (_priv) {
  120. crypto_free_ahash(_priv->tx_tfm_michael);
  121. crypto_free_skcipher(_priv->tx_tfm_arc4);
  122. crypto_free_ahash(_priv->rx_tfm_michael);
  123. crypto_free_skcipher(_priv->rx_tfm_arc4);
  124. }
  125. kfree(priv);
  126. }
  127. static inline u16 RotR1(u16 val)
  128. {
  129. return (val >> 1) | (val << 15);
  130. }
  131. static inline u8 Lo8(u16 val)
  132. {
  133. return val & 0xff;
  134. }
  135. static inline u8 Hi8(u16 val)
  136. {
  137. return val >> 8;
  138. }
  139. static inline u16 Lo16(u32 val)
  140. {
  141. return val & 0xffff;
  142. }
  143. static inline u16 Hi16(u32 val)
  144. {
  145. return val >> 16;
  146. }
  147. static inline u16 Mk16(u8 hi, u8 lo)
  148. {
  149. return lo | (((u16) hi) << 8);
  150. }
  151. static inline u16 Mk16_le(__le16 * v)
  152. {
  153. return le16_to_cpu(*v);
  154. }
  155. static const u16 Sbox[256] = {
  156. 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
  157. 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
  158. 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
  159. 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
  160. 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
  161. 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
  162. 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
  163. 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
  164. 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
  165. 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
  166. 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
  167. 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
  168. 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
  169. 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
  170. 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
  171. 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
  172. 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
  173. 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
  174. 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
  175. 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
  176. 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
  177. 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
  178. 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
  179. 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
  180. 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
  181. 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
  182. 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
  183. 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
  184. 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
  185. 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
  186. 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
  187. 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
  188. };
  189. static inline u16 _S_(u16 v)
  190. {
  191. u16 t = Sbox[Hi8(v)];
  192. return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
  193. }
  194. #define PHASE1_LOOP_COUNT 8
  195. static void tkip_mixing_phase1(u16 * TTAK, const u8 * TK, const u8 * TA,
  196. u32 IV32)
  197. {
  198. int i, j;
  199. /* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
  200. TTAK[0] = Lo16(IV32);
  201. TTAK[1] = Hi16(IV32);
  202. TTAK[2] = Mk16(TA[1], TA[0]);
  203. TTAK[3] = Mk16(TA[3], TA[2]);
  204. TTAK[4] = Mk16(TA[5], TA[4]);
  205. for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
  206. j = 2 * (i & 1);
  207. TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
  208. TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
  209. TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
  210. TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
  211. TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
  212. }
  213. }
  214. static void tkip_mixing_phase2(u8 * WEPSeed, const u8 * TK, const u16 * TTAK,
  215. u16 IV16)
  216. {
  217. /* Make temporary area overlap WEP seed so that the final copy can be
  218. * avoided on little endian hosts. */
  219. u16 *PPK = (u16 *) & WEPSeed[4];
  220. /* Step 1 - make copy of TTAK and bring in TSC */
  221. PPK[0] = TTAK[0];
  222. PPK[1] = TTAK[1];
  223. PPK[2] = TTAK[2];
  224. PPK[3] = TTAK[3];
  225. PPK[4] = TTAK[4];
  226. PPK[5] = TTAK[4] + IV16;
  227. /* Step 2 - 96-bit bijective mixing using S-box */
  228. PPK[0] += _S_(PPK[5] ^ Mk16_le((__le16 *) & TK[0]));
  229. PPK[1] += _S_(PPK[0] ^ Mk16_le((__le16 *) & TK[2]));
  230. PPK[2] += _S_(PPK[1] ^ Mk16_le((__le16 *) & TK[4]));
  231. PPK[3] += _S_(PPK[2] ^ Mk16_le((__le16 *) & TK[6]));
  232. PPK[4] += _S_(PPK[3] ^ Mk16_le((__le16 *) & TK[8]));
  233. PPK[5] += _S_(PPK[4] ^ Mk16_le((__le16 *) & TK[10]));
  234. PPK[0] += RotR1(PPK[5] ^ Mk16_le((__le16 *) & TK[12]));
  235. PPK[1] += RotR1(PPK[0] ^ Mk16_le((__le16 *) & TK[14]));
  236. PPK[2] += RotR1(PPK[1]);
  237. PPK[3] += RotR1(PPK[2]);
  238. PPK[4] += RotR1(PPK[3]);
  239. PPK[5] += RotR1(PPK[4]);
  240. /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
  241. * WEPSeed[0..2] is transmitted as WEP IV */
  242. WEPSeed[0] = Hi8(IV16);
  243. WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
  244. WEPSeed[2] = Lo8(IV16);
  245. WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((__le16 *) & TK[0])) >> 1);
  246. #ifdef __BIG_ENDIAN
  247. {
  248. int i;
  249. for (i = 0; i < 6; i++)
  250. PPK[i] = (PPK[i] << 8) | (PPK[i] >> 8);
  251. }
  252. #endif
  253. }
  254. static int lib80211_tkip_hdr(struct sk_buff *skb, int hdr_len,
  255. u8 * rc4key, int keylen, void *priv)
  256. {
  257. struct lib80211_tkip_data *tkey = priv;
  258. u8 *pos;
  259. struct ieee80211_hdr *hdr;
  260. hdr = (struct ieee80211_hdr *)skb->data;
  261. if (skb_headroom(skb) < TKIP_HDR_LEN || skb->len < hdr_len)
  262. return -1;
  263. if (rc4key == NULL || keylen < 16)
  264. return -1;
  265. if (!tkey->tx_phase1_done) {
  266. tkip_mixing_phase1(tkey->tx_ttak, tkey->key, hdr->addr2,
  267. tkey->tx_iv32);
  268. tkey->tx_phase1_done = 1;
  269. }
  270. tkip_mixing_phase2(rc4key, tkey->key, tkey->tx_ttak, tkey->tx_iv16);
  271. pos = skb_push(skb, TKIP_HDR_LEN);
  272. memmove(pos, pos + TKIP_HDR_LEN, hdr_len);
  273. pos += hdr_len;
  274. *pos++ = *rc4key;
  275. *pos++ = *(rc4key + 1);
  276. *pos++ = *(rc4key + 2);
  277. *pos++ = (tkey->key_idx << 6) | (1 << 5) /* Ext IV included */ ;
  278. *pos++ = tkey->tx_iv32 & 0xff;
  279. *pos++ = (tkey->tx_iv32 >> 8) & 0xff;
  280. *pos++ = (tkey->tx_iv32 >> 16) & 0xff;
  281. *pos++ = (tkey->tx_iv32 >> 24) & 0xff;
  282. tkey->tx_iv16++;
  283. if (tkey->tx_iv16 == 0) {
  284. tkey->tx_phase1_done = 0;
  285. tkey->tx_iv32++;
  286. }
  287. return TKIP_HDR_LEN;
  288. }
  289. static int lib80211_tkip_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
  290. {
  291. struct lib80211_tkip_data *tkey = priv;
  292. SKCIPHER_REQUEST_ON_STACK(req, tkey->tx_tfm_arc4);
  293. int len;
  294. u8 rc4key[16], *pos, *icv;
  295. u32 crc;
  296. struct scatterlist sg;
  297. int err;
  298. if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
  299. struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
  300. net_dbg_ratelimited("TKIP countermeasures: dropped TX packet to %pM\n",
  301. hdr->addr1);
  302. return -1;
  303. }
  304. if (skb_tailroom(skb) < 4 || skb->len < hdr_len)
  305. return -1;
  306. len = skb->len - hdr_len;
  307. pos = skb->data + hdr_len;
  308. if ((lib80211_tkip_hdr(skb, hdr_len, rc4key, 16, priv)) < 0)
  309. return -1;
  310. crc = ~crc32_le(~0, pos, len);
  311. icv = skb_put(skb, 4);
  312. icv[0] = crc;
  313. icv[1] = crc >> 8;
  314. icv[2] = crc >> 16;
  315. icv[3] = crc >> 24;
  316. crypto_skcipher_setkey(tkey->tx_tfm_arc4, rc4key, 16);
  317. sg_init_one(&sg, pos, len + 4);
  318. skcipher_request_set_tfm(req, tkey->tx_tfm_arc4);
  319. skcipher_request_set_callback(req, 0, NULL, NULL);
  320. skcipher_request_set_crypt(req, &sg, &sg, len + 4, NULL);
  321. err = crypto_skcipher_encrypt(req);
  322. skcipher_request_zero(req);
  323. return err;
  324. }
  325. /*
  326. * deal with seq counter wrapping correctly.
  327. * refer to timer_after() for jiffies wrapping handling
  328. */
  329. static inline int tkip_replay_check(u32 iv32_n, u16 iv16_n,
  330. u32 iv32_o, u16 iv16_o)
  331. {
  332. if ((s32)iv32_n - (s32)iv32_o < 0 ||
  333. (iv32_n == iv32_o && iv16_n <= iv16_o))
  334. return 1;
  335. return 0;
  336. }
  337. static int lib80211_tkip_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
  338. {
  339. struct lib80211_tkip_data *tkey = priv;
  340. SKCIPHER_REQUEST_ON_STACK(req, tkey->rx_tfm_arc4);
  341. u8 rc4key[16];
  342. u8 keyidx, *pos;
  343. u32 iv32;
  344. u16 iv16;
  345. struct ieee80211_hdr *hdr;
  346. u8 icv[4];
  347. u32 crc;
  348. struct scatterlist sg;
  349. int plen;
  350. int err;
  351. hdr = (struct ieee80211_hdr *)skb->data;
  352. if (tkey->flags & IEEE80211_CRYPTO_TKIP_COUNTERMEASURES) {
  353. net_dbg_ratelimited("TKIP countermeasures: dropped received packet from %pM\n",
  354. hdr->addr2);
  355. return -1;
  356. }
  357. if (skb->len < hdr_len + TKIP_HDR_LEN + 4)
  358. return -1;
  359. pos = skb->data + hdr_len;
  360. keyidx = pos[3];
  361. if (!(keyidx & (1 << 5))) {
  362. net_dbg_ratelimited("TKIP: received packet without ExtIV flag from %pM\n",
  363. hdr->addr2);
  364. return -2;
  365. }
  366. keyidx >>= 6;
  367. if (tkey->key_idx != keyidx) {
  368. net_dbg_ratelimited("TKIP: RX tkey->key_idx=%d frame keyidx=%d\n",
  369. tkey->key_idx, keyidx);
  370. return -6;
  371. }
  372. if (!tkey->key_set) {
  373. net_dbg_ratelimited("TKIP: received packet from %pM with keyid=%d that does not have a configured key\n",
  374. hdr->addr2, keyidx);
  375. return -3;
  376. }
  377. iv16 = (pos[0] << 8) | pos[2];
  378. iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24);
  379. pos += TKIP_HDR_LEN;
  380. if (tkip_replay_check(iv32, iv16, tkey->rx_iv32, tkey->rx_iv16)) {
  381. #ifdef CONFIG_LIB80211_DEBUG
  382. net_dbg_ratelimited("TKIP: replay detected: STA=%pM previous TSC %08x%04x received TSC %08x%04x\n",
  383. hdr->addr2, tkey->rx_iv32, tkey->rx_iv16,
  384. iv32, iv16);
  385. #endif
  386. tkey->dot11RSNAStatsTKIPReplays++;
  387. return -4;
  388. }
  389. if (iv32 != tkey->rx_iv32 || !tkey->rx_phase1_done) {
  390. tkip_mixing_phase1(tkey->rx_ttak, tkey->key, hdr->addr2, iv32);
  391. tkey->rx_phase1_done = 1;
  392. }
  393. tkip_mixing_phase2(rc4key, tkey->key, tkey->rx_ttak, iv16);
  394. plen = skb->len - hdr_len - 12;
  395. crypto_skcipher_setkey(tkey->rx_tfm_arc4, rc4key, 16);
  396. sg_init_one(&sg, pos, plen + 4);
  397. skcipher_request_set_tfm(req, tkey->rx_tfm_arc4);
  398. skcipher_request_set_callback(req, 0, NULL, NULL);
  399. skcipher_request_set_crypt(req, &sg, &sg, plen + 4, NULL);
  400. err = crypto_skcipher_decrypt(req);
  401. skcipher_request_zero(req);
  402. if (err) {
  403. net_dbg_ratelimited("TKIP: failed to decrypt received packet from %pM\n",
  404. hdr->addr2);
  405. return -7;
  406. }
  407. crc = ~crc32_le(~0, pos, plen);
  408. icv[0] = crc;
  409. icv[1] = crc >> 8;
  410. icv[2] = crc >> 16;
  411. icv[3] = crc >> 24;
  412. if (memcmp(icv, pos + plen, 4) != 0) {
  413. if (iv32 != tkey->rx_iv32) {
  414. /* Previously cached Phase1 result was already lost, so
  415. * it needs to be recalculated for the next packet. */
  416. tkey->rx_phase1_done = 0;
  417. }
  418. #ifdef CONFIG_LIB80211_DEBUG
  419. net_dbg_ratelimited("TKIP: ICV error detected: STA=%pM\n",
  420. hdr->addr2);
  421. #endif
  422. tkey->dot11RSNAStatsTKIPICVErrors++;
  423. return -5;
  424. }
  425. /* Update real counters only after Michael MIC verification has
  426. * completed */
  427. tkey->rx_iv32_new = iv32;
  428. tkey->rx_iv16_new = iv16;
  429. /* Remove IV and ICV */
  430. memmove(skb->data + TKIP_HDR_LEN, skb->data, hdr_len);
  431. skb_pull(skb, TKIP_HDR_LEN);
  432. skb_trim(skb, skb->len - 4);
  433. return keyidx;
  434. }
  435. static int michael_mic(struct crypto_ahash *tfm_michael, u8 * key, u8 * hdr,
  436. u8 * data, size_t data_len, u8 * mic)
  437. {
  438. AHASH_REQUEST_ON_STACK(req, tfm_michael);
  439. struct scatterlist sg[2];
  440. int err;
  441. if (tfm_michael == NULL) {
  442. pr_warn("%s(): tfm_michael == NULL\n", __func__);
  443. return -1;
  444. }
  445. sg_init_table(sg, 2);
  446. sg_set_buf(&sg[0], hdr, 16);
  447. sg_set_buf(&sg[1], data, data_len);
  448. if (crypto_ahash_setkey(tfm_michael, key, 8))
  449. return -1;
  450. ahash_request_set_tfm(req, tfm_michael);
  451. ahash_request_set_callback(req, 0, NULL, NULL);
  452. ahash_request_set_crypt(req, sg, mic, data_len + 16);
  453. err = crypto_ahash_digest(req);
  454. ahash_request_zero(req);
  455. return err;
  456. }
  457. static void michael_mic_hdr(struct sk_buff *skb, u8 * hdr)
  458. {
  459. struct ieee80211_hdr *hdr11;
  460. hdr11 = (struct ieee80211_hdr *)skb->data;
  461. switch (le16_to_cpu(hdr11->frame_control) &
  462. (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
  463. case IEEE80211_FCTL_TODS:
  464. memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
  465. memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
  466. break;
  467. case IEEE80211_FCTL_FROMDS:
  468. memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
  469. memcpy(hdr + ETH_ALEN, hdr11->addr3, ETH_ALEN); /* SA */
  470. break;
  471. case IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS:
  472. memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
  473. memcpy(hdr + ETH_ALEN, hdr11->addr4, ETH_ALEN); /* SA */
  474. break;
  475. case 0:
  476. memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
  477. memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
  478. break;
  479. }
  480. if (ieee80211_is_data_qos(hdr11->frame_control)) {
  481. hdr[12] = le16_to_cpu(*((__le16 *)ieee80211_get_qos_ctl(hdr11)))
  482. & IEEE80211_QOS_CTL_TID_MASK;
  483. } else
  484. hdr[12] = 0; /* priority */
  485. hdr[13] = hdr[14] = hdr[15] = 0; /* reserved */
  486. }
  487. static int lib80211_michael_mic_add(struct sk_buff *skb, int hdr_len,
  488. void *priv)
  489. {
  490. struct lib80211_tkip_data *tkey = priv;
  491. u8 *pos;
  492. if (skb_tailroom(skb) < 8 || skb->len < hdr_len) {
  493. printk(KERN_DEBUG "Invalid packet for Michael MIC add "
  494. "(tailroom=%d hdr_len=%d skb->len=%d)\n",
  495. skb_tailroom(skb), hdr_len, skb->len);
  496. return -1;
  497. }
  498. michael_mic_hdr(skb, tkey->tx_hdr);
  499. pos = skb_put(skb, 8);
  500. if (michael_mic(tkey->tx_tfm_michael, &tkey->key[16], tkey->tx_hdr,
  501. skb->data + hdr_len, skb->len - 8 - hdr_len, pos))
  502. return -1;
  503. return 0;
  504. }
  505. static void lib80211_michael_mic_failure(struct net_device *dev,
  506. struct ieee80211_hdr *hdr,
  507. int keyidx)
  508. {
  509. union iwreq_data wrqu;
  510. struct iw_michaelmicfailure ev;
  511. /* TODO: needed parameters: count, keyid, key type, TSC */
  512. memset(&ev, 0, sizeof(ev));
  513. ev.flags = keyidx & IW_MICFAILURE_KEY_ID;
  514. if (hdr->addr1[0] & 0x01)
  515. ev.flags |= IW_MICFAILURE_GROUP;
  516. else
  517. ev.flags |= IW_MICFAILURE_PAIRWISE;
  518. ev.src_addr.sa_family = ARPHRD_ETHER;
  519. memcpy(ev.src_addr.sa_data, hdr->addr2, ETH_ALEN);
  520. memset(&wrqu, 0, sizeof(wrqu));
  521. wrqu.data.length = sizeof(ev);
  522. wireless_send_event(dev, IWEVMICHAELMICFAILURE, &wrqu, (char *)&ev);
  523. }
  524. static int lib80211_michael_mic_verify(struct sk_buff *skb, int keyidx,
  525. int hdr_len, void *priv)
  526. {
  527. struct lib80211_tkip_data *tkey = priv;
  528. u8 mic[8];
  529. if (!tkey->key_set)
  530. return -1;
  531. michael_mic_hdr(skb, tkey->rx_hdr);
  532. if (michael_mic(tkey->rx_tfm_michael, &tkey->key[24], tkey->rx_hdr,
  533. skb->data + hdr_len, skb->len - 8 - hdr_len, mic))
  534. return -1;
  535. if (memcmp(mic, skb->data + skb->len - 8, 8) != 0) {
  536. struct ieee80211_hdr *hdr;
  537. hdr = (struct ieee80211_hdr *)skb->data;
  538. printk(KERN_DEBUG "%s: Michael MIC verification failed for "
  539. "MSDU from %pM keyidx=%d\n",
  540. skb->dev ? skb->dev->name : "N/A", hdr->addr2,
  541. keyidx);
  542. if (skb->dev)
  543. lib80211_michael_mic_failure(skb->dev, hdr, keyidx);
  544. tkey->dot11RSNAStatsTKIPLocalMICFailures++;
  545. return -1;
  546. }
  547. /* Update TSC counters for RX now that the packet verification has
  548. * completed. */
  549. tkey->rx_iv32 = tkey->rx_iv32_new;
  550. tkey->rx_iv16 = tkey->rx_iv16_new;
  551. skb_trim(skb, skb->len - 8);
  552. return 0;
  553. }
  554. static int lib80211_tkip_set_key(void *key, int len, u8 * seq, void *priv)
  555. {
  556. struct lib80211_tkip_data *tkey = priv;
  557. int keyidx;
  558. struct crypto_ahash *tfm = tkey->tx_tfm_michael;
  559. struct crypto_skcipher *tfm2 = tkey->tx_tfm_arc4;
  560. struct crypto_ahash *tfm3 = tkey->rx_tfm_michael;
  561. struct crypto_skcipher *tfm4 = tkey->rx_tfm_arc4;
  562. keyidx = tkey->key_idx;
  563. memset(tkey, 0, sizeof(*tkey));
  564. tkey->key_idx = keyidx;
  565. tkey->tx_tfm_michael = tfm;
  566. tkey->tx_tfm_arc4 = tfm2;
  567. tkey->rx_tfm_michael = tfm3;
  568. tkey->rx_tfm_arc4 = tfm4;
  569. if (len == TKIP_KEY_LEN) {
  570. memcpy(tkey->key, key, TKIP_KEY_LEN);
  571. tkey->key_set = 1;
  572. tkey->tx_iv16 = 1; /* TSC is initialized to 1 */
  573. if (seq) {
  574. tkey->rx_iv32 = (seq[5] << 24) | (seq[4] << 16) |
  575. (seq[3] << 8) | seq[2];
  576. tkey->rx_iv16 = (seq[1] << 8) | seq[0];
  577. }
  578. } else if (len == 0)
  579. tkey->key_set = 0;
  580. else
  581. return -1;
  582. return 0;
  583. }
  584. static int lib80211_tkip_get_key(void *key, int len, u8 * seq, void *priv)
  585. {
  586. struct lib80211_tkip_data *tkey = priv;
  587. if (len < TKIP_KEY_LEN)
  588. return -1;
  589. if (!tkey->key_set)
  590. return 0;
  591. memcpy(key, tkey->key, TKIP_KEY_LEN);
  592. if (seq) {
  593. /* Return the sequence number of the last transmitted frame. */
  594. u16 iv16 = tkey->tx_iv16;
  595. u32 iv32 = tkey->tx_iv32;
  596. if (iv16 == 0)
  597. iv32--;
  598. iv16--;
  599. seq[0] = tkey->tx_iv16;
  600. seq[1] = tkey->tx_iv16 >> 8;
  601. seq[2] = tkey->tx_iv32;
  602. seq[3] = tkey->tx_iv32 >> 8;
  603. seq[4] = tkey->tx_iv32 >> 16;
  604. seq[5] = tkey->tx_iv32 >> 24;
  605. }
  606. return TKIP_KEY_LEN;
  607. }
  608. static void lib80211_tkip_print_stats(struct seq_file *m, void *priv)
  609. {
  610. struct lib80211_tkip_data *tkip = priv;
  611. seq_printf(m,
  612. "key[%d] alg=TKIP key_set=%d "
  613. "tx_pn=%02x%02x%02x%02x%02x%02x "
  614. "rx_pn=%02x%02x%02x%02x%02x%02x "
  615. "replays=%d icv_errors=%d local_mic_failures=%d\n",
  616. tkip->key_idx, tkip->key_set,
  617. (tkip->tx_iv32 >> 24) & 0xff,
  618. (tkip->tx_iv32 >> 16) & 0xff,
  619. (tkip->tx_iv32 >> 8) & 0xff,
  620. tkip->tx_iv32 & 0xff,
  621. (tkip->tx_iv16 >> 8) & 0xff,
  622. tkip->tx_iv16 & 0xff,
  623. (tkip->rx_iv32 >> 24) & 0xff,
  624. (tkip->rx_iv32 >> 16) & 0xff,
  625. (tkip->rx_iv32 >> 8) & 0xff,
  626. tkip->rx_iv32 & 0xff,
  627. (tkip->rx_iv16 >> 8) & 0xff,
  628. tkip->rx_iv16 & 0xff,
  629. tkip->dot11RSNAStatsTKIPReplays,
  630. tkip->dot11RSNAStatsTKIPICVErrors,
  631. tkip->dot11RSNAStatsTKIPLocalMICFailures);
  632. }
  633. static struct lib80211_crypto_ops lib80211_crypt_tkip = {
  634. .name = "TKIP",
  635. .init = lib80211_tkip_init,
  636. .deinit = lib80211_tkip_deinit,
  637. .encrypt_mpdu = lib80211_tkip_encrypt,
  638. .decrypt_mpdu = lib80211_tkip_decrypt,
  639. .encrypt_msdu = lib80211_michael_mic_add,
  640. .decrypt_msdu = lib80211_michael_mic_verify,
  641. .set_key = lib80211_tkip_set_key,
  642. .get_key = lib80211_tkip_get_key,
  643. .print_stats = lib80211_tkip_print_stats,
  644. .extra_mpdu_prefix_len = 4 + 4, /* IV + ExtIV */
  645. .extra_mpdu_postfix_len = 4, /* ICV */
  646. .extra_msdu_postfix_len = 8, /* MIC */
  647. .get_flags = lib80211_tkip_get_flags,
  648. .set_flags = lib80211_tkip_set_flags,
  649. .owner = THIS_MODULE,
  650. };
  651. static int __init lib80211_crypto_tkip_init(void)
  652. {
  653. return lib80211_register_crypto_ops(&lib80211_crypt_tkip);
  654. }
  655. static void __exit lib80211_crypto_tkip_exit(void)
  656. {
  657. lib80211_unregister_crypto_ops(&lib80211_crypt_tkip);
  658. }
  659. module_init(lib80211_crypto_tkip_init);
  660. module_exit(lib80211_crypto_tkip_exit);