tkip.c 10.0 KB

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  1. /*
  2. * Temporal Key Integrity Protocol (CCMP)
  3. * Copyright (c) 2010, Jouni Malinen <j@w1.fi>
  4. *
  5. * This program is free software; you can redistribute it and/or modify
  6. * it under the terms of the GNU General Public License version 2 as
  7. * published by the Free Software Foundation.
  8. *
  9. * Alternatively, this software may be distributed under the terms of BSD
  10. * license.
  11. *
  12. * See README and COPYING for more details.
  13. */
  14. #include "utils/includes.h"
  15. #include "utils/common.h"
  16. #include "common/ieee802_11_defs.h"
  17. #include "wlantest.h"
  18. void wep_crypt(u8 *key, u8 *buf, size_t plen);
  19. static inline u16 RotR1(u16 val)
  20. {
  21. return (val >> 1) | (val << 15);
  22. }
  23. static inline u8 Lo8(u16 val)
  24. {
  25. return val & 0xff;
  26. }
  27. static inline u8 Hi8(u16 val)
  28. {
  29. return val >> 8;
  30. }
  31. static inline u16 Lo16(u32 val)
  32. {
  33. return val & 0xffff;
  34. }
  35. static inline u16 Hi16(u32 val)
  36. {
  37. return val >> 16;
  38. }
  39. static inline u16 Mk16(u8 hi, u8 lo)
  40. {
  41. return lo | (((u16) hi) << 8);
  42. }
  43. static inline u16 Mk16_le(u16 *v)
  44. {
  45. return le_to_host16(*v);
  46. }
  47. static const u16 Sbox[256] =
  48. {
  49. 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
  50. 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
  51. 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
  52. 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
  53. 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
  54. 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
  55. 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
  56. 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
  57. 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
  58. 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
  59. 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
  60. 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
  61. 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
  62. 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
  63. 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
  64. 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
  65. 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
  66. 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
  67. 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
  68. 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
  69. 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
  70. 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
  71. 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
  72. 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
  73. 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
  74. 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
  75. 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
  76. 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
  77. 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
  78. 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
  79. 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
  80. 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
  81. };
  82. static inline u16 _S_(u16 v)
  83. {
  84. u16 t = Sbox[Hi8(v)];
  85. return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
  86. }
  87. #define PHASE1_LOOP_COUNT 8
  88. static void tkip_mixing_phase1(u16 *TTAK, const u8 *TK, const u8 *TA, u32 IV32)
  89. {
  90. int i, j;
  91. /* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
  92. TTAK[0] = Lo16(IV32);
  93. TTAK[1] = Hi16(IV32);
  94. TTAK[2] = Mk16(TA[1], TA[0]);
  95. TTAK[3] = Mk16(TA[3], TA[2]);
  96. TTAK[4] = Mk16(TA[5], TA[4]);
  97. for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
  98. j = 2 * (i & 1);
  99. TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
  100. TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
  101. TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
  102. TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
  103. TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
  104. }
  105. }
  106. static void tkip_mixing_phase2(u8 *WEPSeed, const u8 *TK, const u16 *TTAK,
  107. u16 IV16)
  108. {
  109. u16 PPK[6];
  110. /* Step 1 - make copy of TTAK and bring in TSC */
  111. PPK[0] = TTAK[0];
  112. PPK[1] = TTAK[1];
  113. PPK[2] = TTAK[2];
  114. PPK[3] = TTAK[3];
  115. PPK[4] = TTAK[4];
  116. PPK[5] = TTAK[4] + IV16;
  117. /* Step 2 - 96-bit bijective mixing using S-box */
  118. PPK[0] += _S_(PPK[5] ^ Mk16_le((u16 *) &TK[0]));
  119. PPK[1] += _S_(PPK[0] ^ Mk16_le((u16 *) &TK[2]));
  120. PPK[2] += _S_(PPK[1] ^ Mk16_le((u16 *) &TK[4]));
  121. PPK[3] += _S_(PPK[2] ^ Mk16_le((u16 *) &TK[6]));
  122. PPK[4] += _S_(PPK[3] ^ Mk16_le((u16 *) &TK[8]));
  123. PPK[5] += _S_(PPK[4] ^ Mk16_le((u16 *) &TK[10]));
  124. PPK[0] += RotR1(PPK[5] ^ Mk16_le((u16 *) &TK[12]));
  125. PPK[1] += RotR1(PPK[0] ^ Mk16_le((u16 *) &TK[14]));
  126. PPK[2] += RotR1(PPK[1]);
  127. PPK[3] += RotR1(PPK[2]);
  128. PPK[4] += RotR1(PPK[3]);
  129. PPK[5] += RotR1(PPK[4]);
  130. /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
  131. * WEPSeed[0..2] is transmitted as WEP IV */
  132. WEPSeed[0] = Hi8(IV16);
  133. WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
  134. WEPSeed[2] = Lo8(IV16);
  135. WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((u16 *) &TK[0])) >> 1);
  136. WPA_PUT_LE16(&WEPSeed[4], PPK[0]);
  137. WPA_PUT_LE16(&WEPSeed[6], PPK[1]);
  138. WPA_PUT_LE16(&WEPSeed[8], PPK[2]);
  139. WPA_PUT_LE16(&WEPSeed[10], PPK[3]);
  140. WPA_PUT_LE16(&WEPSeed[12], PPK[4]);
  141. WPA_PUT_LE16(&WEPSeed[14], PPK[5]);
  142. }
  143. static inline u32 rotl(u32 val, int bits)
  144. {
  145. return (val << bits) | (val >> (32 - bits));
  146. }
  147. static inline u32 rotr(u32 val, int bits)
  148. {
  149. return (val >> bits) | (val << (32 - bits));
  150. }
  151. static inline u32 xswap(u32 val)
  152. {
  153. return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
  154. }
  155. #define michael_block(l, r) \
  156. do { \
  157. r ^= rotl(l, 17); \
  158. l += r; \
  159. r ^= xswap(l); \
  160. l += r; \
  161. r ^= rotl(l, 3); \
  162. l += r; \
  163. r ^= rotr(l, 2); \
  164. l += r; \
  165. } while (0)
  166. static void michael_mic(const u8 *key, const u8 *hdr, const u8 *data,
  167. size_t data_len, u8 *mic)
  168. {
  169. u32 l, r;
  170. int i, blocks, last;
  171. l = WPA_GET_LE32(key);
  172. r = WPA_GET_LE32(key + 4);
  173. /* Michael MIC pseudo header: DA, SA, 3 x 0, Priority */
  174. l ^= WPA_GET_LE32(hdr);
  175. michael_block(l, r);
  176. l ^= WPA_GET_LE32(&hdr[4]);
  177. michael_block(l, r);
  178. l ^= WPA_GET_LE32(&hdr[8]);
  179. michael_block(l, r);
  180. l ^= WPA_GET_LE32(&hdr[12]);
  181. michael_block(l, r);
  182. /* 32-bit blocks of data */
  183. blocks = data_len / 4;
  184. last = data_len % 4;
  185. for (i = 0; i < blocks; i++) {
  186. l ^= WPA_GET_LE32(&data[4 * i]);
  187. michael_block(l, r);
  188. }
  189. /* Last block and padding (0x5a, 4..7 x 0) */
  190. switch (last) {
  191. case 0:
  192. l ^= 0x5a;
  193. break;
  194. case 1:
  195. l ^= data[4 * i] | 0x5a00;
  196. break;
  197. case 2:
  198. l ^= data[4 * i] | (data[4 * i + 1] << 8) | 0x5a0000;
  199. break;
  200. case 3:
  201. l ^= data[4 * i] | (data[4 * i + 1] << 8) |
  202. (data[4 * i + 2] << 16) | 0x5a000000;
  203. break;
  204. }
  205. michael_block(l, r);
  206. /* l ^= 0; */
  207. michael_block(l, r);
  208. WPA_PUT_LE32(mic, l);
  209. WPA_PUT_LE32(mic + 4, r);
  210. }
  211. static void michael_mic_hdr(const struct ieee80211_hdr *hdr11, u8 *hdr)
  212. {
  213. int hdrlen = 24;
  214. u16 fc = le_to_host16(hdr11->frame_control);
  215. switch (fc & (WLAN_FC_FROMDS | WLAN_FC_TODS)) {
  216. case WLAN_FC_TODS:
  217. os_memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
  218. os_memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
  219. break;
  220. case WLAN_FC_FROMDS:
  221. os_memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
  222. os_memcpy(hdr + ETH_ALEN, hdr11->addr3, ETH_ALEN); /* SA */
  223. break;
  224. case WLAN_FC_FROMDS | WLAN_FC_TODS:
  225. os_memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
  226. os_memcpy(hdr + ETH_ALEN, hdr11 + 1, ETH_ALEN); /* SA */
  227. hdrlen += ETH_ALEN;
  228. break;
  229. case 0:
  230. os_memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
  231. os_memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
  232. break;
  233. }
  234. if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_DATA &&
  235. (WLAN_FC_GET_STYPE(fc) & 0x08)) {
  236. const u8 *qos = ((const u8 *) hdr11) + hdrlen;
  237. hdr[12] = qos[0] & 0x0f; /* priority */
  238. } else
  239. hdr[12] = 0; /* priority */
  240. hdr[13] = hdr[14] = hdr[15] = 0; /* reserved */
  241. }
  242. u8 * tkip_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
  243. const u8 *data, size_t data_len, size_t *decrypted_len)
  244. {
  245. u16 iv16;
  246. u32 iv32;
  247. u16 ttak[5];
  248. u8 rc4key[16];
  249. u8 *plain;
  250. size_t plain_len;
  251. u32 icv, rx_icv;
  252. const u8 *mic_key;
  253. u8 michael_hdr[16];
  254. u8 mic[8];
  255. u16 fc = le_to_host16(hdr->frame_control);
  256. if (data_len < 8 + 4)
  257. return NULL;
  258. iv16 = (data[0] << 8) | data[2];
  259. iv32 = WPA_GET_LE32(&data[4]);
  260. wpa_printf(MSG_EXCESSIVE, "TKIP decrypt: iv32=%08x iv16=%04x",
  261. iv32, iv16);
  262. tkip_mixing_phase1(ttak, tk, hdr->addr2, iv32);
  263. wpa_hexdump(MSG_EXCESSIVE, "TKIP TTAK", (u8 *) ttak, sizeof(ttak));
  264. tkip_mixing_phase2(rc4key, tk, ttak, iv16);
  265. wpa_hexdump(MSG_EXCESSIVE, "TKIP RC4KEY", rc4key, sizeof(rc4key));
  266. plain_len = data_len - 8;
  267. plain = os_malloc(plain_len);
  268. if (plain == NULL)
  269. return NULL;
  270. os_memcpy(plain, data + 8, plain_len);
  271. wep_crypt(rc4key, plain, plain_len);
  272. icv = crc32(plain, plain_len - 4);
  273. rx_icv = WPA_GET_LE32(plain + plain_len - 4);
  274. if (icv != rx_icv) {
  275. wpa_printf(MSG_INFO, "TKIP ICV mismatch in frame from " MACSTR,
  276. MAC2STR(hdr->addr2));
  277. wpa_printf(MSG_DEBUG, "TKIP calculated ICV %08x received ICV "
  278. "%08x", icv, rx_icv);
  279. os_free(plain);
  280. return NULL;
  281. }
  282. plain_len -= 4;
  283. /* TODO: MSDU reassembly */
  284. if (plain_len < 8) {
  285. wpa_printf(MSG_INFO, "TKIP: Not enough room for Michael MIC "
  286. "in a frame from " MACSTR, MAC2STR(hdr->addr2));
  287. os_free(plain);
  288. return NULL;
  289. }
  290. michael_mic_hdr(hdr, michael_hdr);
  291. mic_key = tk + ((fc & WLAN_FC_FROMDS) ? 16 : 24);
  292. michael_mic(mic_key, michael_hdr, plain, plain_len - 8, mic);
  293. if (os_memcmp(mic, plain + plain_len - 8, 8) != 0) {
  294. wpa_printf(MSG_INFO, "TKIP: Michael MIC mismatch in a frame "
  295. "from " MACSTR, MAC2STR(hdr->addr2));
  296. wpa_hexdump(MSG_DEBUG, "TKIP: Calculated MIC", mic, 8);
  297. wpa_hexdump(MSG_DEBUG, "TKIP: Received MIC",
  298. plain + plain_len - 8, 8);
  299. os_free(plain);
  300. return NULL;
  301. }
  302. *decrypted_len = plain_len - 8;
  303. return plain;
  304. }
  305. void tkip_get_pn(u8 *pn, const u8 *data)
  306. {
  307. pn[0] = data[7]; /* PN5 */
  308. pn[1] = data[6]; /* PN4 */
  309. pn[2] = data[5]; /* PN3 */
  310. pn[3] = data[4]; /* PN2 */
  311. pn[4] = data[0]; /* PN1 */
  312. pn[5] = data[2]; /* PN0 */
  313. }
  314. u8 * tkip_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
  315. u8 *pn, int keyid, size_t *encrypted_len)
  316. {
  317. /* TODO */
  318. return NULL;
  319. }