wlantest/tkip.c

   1 /*
   2  * Temporal Key Integrity Protocol (CCMP)
   3  * Copyright (c) 2010, Jouni Malinen <j@w1.fi>
   4  *
   5  * This software may be distributed under the terms of the BSD license.
   6  * See README for more details.
   7  */
   8
   9 #include "utils/includes.h"
  10
  11 #include "utils/common.h"
  12 #include "utils/crc32.h"
  13 #include "common/ieee802_11_defs.h"
  14 #include "wlantest.h"
  15
  16
  17 void wep_crypt(u8 *key, u8 *buf, size_t plen);
  18
  19
  20 static inline u16 RotR1(u16 val)
  21 {
  22         return (val >> 1) | (val << 15);
  23 }
  24
  25
  26 static inline u8 Lo8(u16 val)
  27 {
  28         return val & 0xff;
  29 }
  30
  31
  32 static inline u8 Hi8(u16 val)
  33 {
  34         return val >> 8;
  35 }
  36
  37
  38 static inline u16 Lo16(u32 val)
  39 {
  40         return val & 0xffff;
  41 }
  42
  43
  44 static inline u16 Hi16(u32 val)
  45 {
  46         return val >> 16;
  47 }
  48
  49
  50 static inline u16 Mk16(u8 hi, u8 lo)
  51 {
  52         return lo | (((u16) hi) << 8);
  53 }
  54
  55
  56 static inline u16 Mk16_le(u16 *v)
  57 {
  58         return le_to_host16(*v);
  59 }
  60
  61
  62 static const u16 Sbox[256] =
  63 {
  64         0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
  65         0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
  66         0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
  67         0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
  68         0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
  69         0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
  70         0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
  71         0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
  72         0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
  73         0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
  74         0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
  75         0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
  76         0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
  77         0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
  78         0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
  79         0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
  80         0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
  81         0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
  82         0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
  83         0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
  84         0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
  85         0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
  86         0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
  87         0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
  88         0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
  89         0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
  90         0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
  91         0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
  92         0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
  93         0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
  94         0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
  95         0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
  96 };
  97
  98
  99 static inline u16 _S_(u16 v)
 100 {
 101         u16 t = Sbox[Hi8(v)];
 102         return Sbox[Lo8(v)] ^ ((t << 8) | (t >> 8));
 103 }
 104
 105
 106 #define PHASE1_LOOP_COUNT 8
 107
 108 static void tkip_mixing_phase1(u16 *TTAK, const u8 *TK, const u8 *TA, u32 IV32)
 109 {
 110         int i, j;
 111
 112         /* Initialize the 80-bit TTAK from TSC (IV32) and TA[0..5] */
 113         TTAK[0] = Lo16(IV32);
 114         TTAK[1] = Hi16(IV32);
 115         TTAK[2] = Mk16(TA[1], TA[0]);
 116         TTAK[3] = Mk16(TA[3], TA[2]);
 117         TTAK[4] = Mk16(TA[5], TA[4]);
 118
 119         for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
 120                 j = 2 * (i & 1);
 121                 TTAK[0] += _S_(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]));
 122                 TTAK[1] += _S_(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]));
 123                 TTAK[2] += _S_(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]));
 124                 TTAK[3] += _S_(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]));
 125                 TTAK[4] += _S_(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j])) + i;
 126         }
 127 }
 128
 129
 130 static void tkip_mixing_phase2(u8 *WEPSeed, const u8 *TK, const u16 *TTAK,
 131                                u16 IV16)
 132 {
 133         u16 PPK[6];
 134
 135         /* Step 1 - make copy of TTAK and bring in TSC */
 136         PPK[0] = TTAK[0];
 137         PPK[1] = TTAK[1];
 138         PPK[2] = TTAK[2];
 139         PPK[3] = TTAK[3];
 140         PPK[4] = TTAK[4];
 141         PPK[5] = TTAK[4] + IV16;
 142
 143         /* Step 2 - 96-bit bijective mixing using S-box */
 144         PPK[0] += _S_(PPK[5] ^ Mk16_le((u16 *) &TK[0]));
 145         PPK[1] += _S_(PPK[0] ^ Mk16_le((u16 *) &TK[2]));
 146         PPK[2] += _S_(PPK[1] ^ Mk16_le((u16 *) &TK[4]));
 147         PPK[3] += _S_(PPK[2] ^ Mk16_le((u16 *) &TK[6]));
 148         PPK[4] += _S_(PPK[3] ^ Mk16_le((u16 *) &TK[8]));
 149         PPK[5] += _S_(PPK[4] ^ Mk16_le((u16 *) &TK[10]));
 150
 151         PPK[0] += RotR1(PPK[5] ^ Mk16_le((u16 *) &TK[12]));
 152         PPK[1] += RotR1(PPK[0] ^ Mk16_le((u16 *) &TK[14]));
 153         PPK[2] += RotR1(PPK[1]);
 154         PPK[3] += RotR1(PPK[2]);
 155         PPK[4] += RotR1(PPK[3]);
 156         PPK[5] += RotR1(PPK[4]);
 157
 158         /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
 159          * WEPSeed[0..2] is transmitted as WEP IV */
 160         WEPSeed[0] = Hi8(IV16);
 161         WEPSeed[1] = (Hi8(IV16) | 0x20) & 0x7F;
 162         WEPSeed[2] = Lo8(IV16);
 163         WEPSeed[3] = Lo8((PPK[5] ^ Mk16_le((u16 *) &TK[0])) >> 1);
 164         WPA_PUT_LE16(&WEPSeed[4], PPK[0]);
 165         WPA_PUT_LE16(&WEPSeed[6], PPK[1]);
 166         WPA_PUT_LE16(&WEPSeed[8], PPK[2]);
 167         WPA_PUT_LE16(&WEPSeed[10], PPK[3]);
 168         WPA_PUT_LE16(&WEPSeed[12], PPK[4]);
 169         WPA_PUT_LE16(&WEPSeed[14], PPK[5]);
 170 }
 171
 172
 173 static inline u32 rotl(u32 val, int bits)
 174 {
 175         return (val << bits) | (val >> (32 - bits));
 176 }
 177
 178
 179 static inline u32 rotr(u32 val, int bits)
 180 {
 181         return (val >> bits) | (val << (32 - bits));
 182 }
 183
 184
 185 static inline u32 xswap(u32 val)
 186 {
 187         return ((val & 0x00ff00ff) << 8) | ((val & 0xff00ff00) >> 8);
 188 }
 189
 190
 191 #define michael_block(l, r)     \
 192 do {                            \
 193         r ^= rotl(l, 17);       \
 194         l += r;                 \
 195         r ^= xswap(l);          \
 196         l += r;                 \
 197         r ^= rotl(l, 3);        \
 198         l += r;                 \
 199         r ^= rotr(l, 2);        \
 200         l += r;                 \
 201 } while (0)
 202
 203
 204 static void michael_mic(const u8 *key, const u8 *hdr, const u8 *data,
 205                         size_t data_len, u8 *mic)
 206 {
 207         u32 l, r;
 208         int i, blocks, last;
 209
 210         l = WPA_GET_LE32(key);
 211         r = WPA_GET_LE32(key + 4);
 212
 213         /* Michael MIC pseudo header: DA, SA, 3 x 0, Priority */
 214         l ^= WPA_GET_LE32(hdr);
 215         michael_block(l, r);
 216         l ^= WPA_GET_LE32(&hdr[4]);
 217         michael_block(l, r);
 218         l ^= WPA_GET_LE32(&hdr[8]);
 219         michael_block(l, r);
 220         l ^= WPA_GET_LE32(&hdr[12]);
 221         michael_block(l, r);
 222
 223         /* 32-bit blocks of data */
 224         blocks = data_len / 4;
 225         last = data_len % 4;
 226         for (i = 0; i < blocks; i++) {
 227                 l ^= WPA_GET_LE32(&data[4 * i]);
 228                 michael_block(l, r);
 229         }
 230
 231         /* Last block and padding (0x5a, 4..7 x 0) */
 232         switch (last) {
 233         case 0:
 234                 l ^= 0x5a;
 235                 break;
 236         case 1:
 237                 l ^= data[4 * i] | 0x5a00;
 238                 break;
 239         case 2:
 240                 l ^= data[4 * i] | (data[4 * i + 1] << 8) | 0x5a0000;
 241                 break;
 242         case 3:
 243                 l ^= data[4 * i] | (data[4 * i + 1] << 8) |
 244                         (data[4 * i + 2] << 16) | 0x5a000000;
 245                 break;
 246         }
 247         michael_block(l, r);
 248         /* l ^= 0; */
 249         michael_block(l, r);
 250
 251         WPA_PUT_LE32(mic, l);
 252         WPA_PUT_LE32(mic + 4, r);
 253 }
 254
 255
 256 static void michael_mic_hdr(const struct ieee80211_hdr *hdr11, u8 *hdr)
 257 {
 258         int hdrlen = 24;
 259         u16 fc = le_to_host16(hdr11->frame_control);
 260
 261         switch (fc & (WLAN_FC_FROMDS | WLAN_FC_TODS)) {
 262         case WLAN_FC_TODS:
 263                 os_memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
 264                 os_memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
 265                 break;
 266         case WLAN_FC_FROMDS:
 267                 os_memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
 268                 os_memcpy(hdr + ETH_ALEN, hdr11->addr3, ETH_ALEN); /* SA */
 269                 break;
 270         case WLAN_FC_FROMDS | WLAN_FC_TODS:
 271                 os_memcpy(hdr, hdr11->addr3, ETH_ALEN); /* DA */
 272                 os_memcpy(hdr + ETH_ALEN, hdr11 + 1, ETH_ALEN); /* SA */
 273                 hdrlen += ETH_ALEN;
 274                 break;
 275         case 0:
 276                 os_memcpy(hdr, hdr11->addr1, ETH_ALEN); /* DA */
 277                 os_memcpy(hdr + ETH_ALEN, hdr11->addr2, ETH_ALEN); /* SA */
 278                 break;
 279         }
 280
 281         if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_DATA &&
 282             (WLAN_FC_GET_STYPE(fc) & 0x08)) {
 283                 const u8 *qos = ((const u8 *) hdr11) + hdrlen;
 284                 hdr[12] = qos[0] & 0x0f; /* priority */
 285         } else
 286                 hdr[12] = 0; /* priority */
 287
 288         hdr[13] = hdr[14] = hdr[15] = 0; /* reserved */
 289 }
 290
 291
 292 u8 * tkip_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
 293                   const u8 *data, size_t data_len, size_t *decrypted_len)
 294 {
 295         u16 iv16;
 296         u32 iv32;
 297         u16 ttak[5];
 298         u8 rc4key[16];
 299         u8 *plain;
 300         size_t plain_len;
 301         u32 icv, rx_icv;
 302         const u8 *mic_key;
 303         u8 michael_hdr[16];
 304         u8 mic[8];
 305         u16 fc = le_to_host16(hdr->frame_control);
 306
 307         if (data_len < 8 + 4)
 308                 return NULL;
 309
 310         iv16 = (data[0] << 8) | data[2];
 311         iv32 = WPA_GET_LE32(&data[4]);
 312         wpa_printf(MSG_EXCESSIVE, "TKIP decrypt: iv32=%08x iv16=%04x",
 313                    iv32, iv16);
 314
 315         tkip_mixing_phase1(ttak, tk, hdr->addr2, iv32);
 316         wpa_hexdump(MSG_EXCESSIVE, "TKIP TTAK", (u8 *) ttak, sizeof(ttak));
 317         tkip_mixing_phase2(rc4key, tk, ttak, iv16);
 318         wpa_hexdump(MSG_EXCESSIVE, "TKIP RC4KEY", rc4key, sizeof(rc4key));
 319
 320         plain_len = data_len - 8;
 321         plain = os_memdup(data + 8, plain_len);
 322         if (plain == NULL)
 323                 return NULL;
 324         wep_crypt(rc4key, plain, plain_len);
 325
 326         icv = crc32(plain, plain_len - 4);
 327         rx_icv = WPA_GET_LE32(plain + plain_len - 4);
 328         if (icv != rx_icv) {
 329                 wpa_printf(MSG_INFO, "TKIP ICV mismatch in frame from " MACSTR,
 330                            MAC2STR(hdr->addr2));
 331                 wpa_printf(MSG_DEBUG, "TKIP calculated ICV %08x  received ICV "
 332                            "%08x", icv, rx_icv);
 333                 os_free(plain);
 334                 return NULL;
 335         }
 336         plain_len -= 4;
 337
 338         /* TODO: MSDU reassembly */
 339
 340         if (plain_len < 8) {
 341                 wpa_printf(MSG_INFO, "TKIP: Not enough room for Michael MIC "
 342                            "in a frame from " MACSTR, MAC2STR(hdr->addr2));
 343                 os_free(plain);
 344                 return NULL;
 345         }
 346
 347         michael_mic_hdr(hdr, michael_hdr);
 348         mic_key = tk + ((fc & WLAN_FC_FROMDS) ? 16 : 24);
 349         michael_mic(mic_key, michael_hdr, plain, plain_len - 8, mic);
 350         if (os_memcmp(mic, plain + plain_len - 8, 8) != 0) {
 351                 wpa_printf(MSG_INFO, "TKIP: Michael MIC mismatch in a frame "
 352                            "from " MACSTR, MAC2STR(hdr->addr2));
 353                 wpa_hexdump(MSG_DEBUG, "TKIP: Calculated MIC", mic, 8);
 354                 wpa_hexdump(MSG_DEBUG, "TKIP: Received MIC",
 355                             plain + plain_len - 8, 8);
 356                 os_free(plain);
 357                 return NULL;
 358         }
 359
 360         *decrypted_len = plain_len - 8;
 361         return plain;
 362 }
 363
 364
 365 void tkip_get_pn(u8 *pn, const u8 *data)
 366 {
 367         pn[0] = data[7]; /* PN5 */
 368         pn[1] = data[6]; /* PN4 */
 369         pn[2] = data[5]; /* PN3 */
 370         pn[3] = data[4]; /* PN2 */
 371         pn[4] = data[0]; /* PN1 */
 372         pn[5] = data[2]; /* PN0 */
 373 }
 374
 375
 376 u8 * tkip_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
 377                   u8 *pn, int keyid, size_t *encrypted_len)
 378 {
 379         u8 michael_hdr[16];
 380         u8 mic[8];
 381         struct ieee80211_hdr *hdr;
 382         u16 fc;
 383         const u8 *mic_key;
 384         u8 *crypt, *pos;
 385         u16 iv16;
 386         u32 iv32;
 387         u16 ttak[5];
 388         u8 rc4key[16];
 389
 390         if (len < sizeof(*hdr) || len < hdrlen)
 391                 return NULL;
 392         hdr = (struct ieee80211_hdr *) frame;
 393         fc = le_to_host16(hdr->frame_control);
 394
 395         michael_mic_hdr(hdr, michael_hdr);
 396         mic_key = tk + ((fc & WLAN_FC_FROMDS) ? 16 : 24);
 397         michael_mic(mic_key, michael_hdr, frame + hdrlen, len - hdrlen, mic);
 398         wpa_hexdump(MSG_EXCESSIVE, "TKIP: MIC", mic, sizeof(mic));
 399
 400         iv32 = WPA_GET_BE32(pn);
 401         iv16 = WPA_GET_BE16(pn + 4);
 402         tkip_mixing_phase1(ttak, tk, hdr->addr2, iv32);
 403         wpa_hexdump(MSG_EXCESSIVE, "TKIP TTAK", (u8 *) ttak, sizeof(ttak));
 404         tkip_mixing_phase2(rc4key, tk, ttak, iv16);
 405         wpa_hexdump(MSG_EXCESSIVE, "TKIP RC4KEY", rc4key, sizeof(rc4key));
 406
 407         crypt = os_malloc(len + 8 + sizeof(mic) + 4);
 408         if (crypt == NULL)
 409                 return NULL;
 410         os_memcpy(crypt, frame, hdrlen);
 411         pos = crypt + hdrlen;
 412         os_memcpy(pos, rc4key, 3);
 413         pos += 3;
 414         *pos++ = keyid << 6 | BIT(5);
 415         *pos++ = pn[3];
 416         *pos++ = pn[2];
 417         *pos++ = pn[1];
 418         *pos++ = pn[0];
 419
 420         os_memcpy(pos, frame + hdrlen, len - hdrlen);
 421         os_memcpy(pos + len - hdrlen, mic, sizeof(mic));
 422         WPA_PUT_LE32(pos + len - hdrlen + sizeof(mic),
 423                      crc32(pos, len - hdrlen + sizeof(mic)));
 424         wep_crypt(rc4key, pos, len - hdrlen + sizeof(mic) + 4);
 425
 426         *encrypted_len = len + 8 + sizeof(mic) + 4;
 427         return crypt;
 428 }