1 /* 2 * Copyright 2002-2004, Instant802 Networks, Inc. 3 * Copyright 2005, Devicescape Software, Inc. 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 10 #include <linux/kernel.h> 11 #include <linux/types.h> 12 #include <linux/netdevice.h> 13 14 #include <net/mac80211.h> 15 #include "ieee80211_key.h" 16 #include "tkip.h" 17 #include "wep.h" 18 19 20 /* TKIP key mixing functions */ 21 22 23 #define PHASE1_LOOP_COUNT 8 24 25 26 /* 2-byte by 2-byte subset of the full AES S-box table; second part of this 27 * table is identical to first part but byte-swapped */ 28 static const u16 tkip_sbox[256] = 29 { 30 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154, 31 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A, 32 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B, 33 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B, 34 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F, 35 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F, 36 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5, 37 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F, 38 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB, 39 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397, 40 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED, 41 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A, 42 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194, 43 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3, 44 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104, 45 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D, 46 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39, 47 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695, 48 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83, 49 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76, 50 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4, 51 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B, 52 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0, 53 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018, 54 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751, 55 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85, 56 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12, 57 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9, 58 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7, 59 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A, 60 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8, 61 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A, 62 }; 63 64 65 static inline u16 Mk16(u8 x, u8 y) 66 { 67 return ((u16) x << 8) | (u16) y; 68 } 69 70 71 static inline u8 Hi8(u16 v) 72 { 73 return v >> 8; 74 } 75 76 77 static inline u8 Lo8(u16 v) 78 { 79 return v & 0xff; 80 } 81 82 83 static inline u16 Hi16(u32 v) 84 { 85 return v >> 16; 86 } 87 88 89 static inline u16 Lo16(u32 v) 90 { 91 return v & 0xffff; 92 } 93 94 95 static inline u16 RotR1(u16 v) 96 { 97 return (v >> 1) | ((v & 0x0001) << 15); 98 } 99 100 101 static inline u16 tkip_S(u16 val) 102 { 103 u16 a = tkip_sbox[Hi8(val)]; 104 105 return tkip_sbox[Lo8(val)] ^ Hi8(a) ^ (Lo8(a) << 8); 106 } 107 108 109 110 /* P1K := Phase1(TA, TK, TSC) 111 * TA = transmitter address (48 bits) 112 * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits) 113 * TSC = TKIP sequence counter (48 bits, only 32 msb bits used) 114 * P1K: 80 bits 115 */ 116 static void tkip_mixing_phase1(const u8 *ta, const u8 *tk, u32 tsc_IV32, 117 u16 *p1k) 118 { 119 int i, j; 120 121 p1k[0] = Lo16(tsc_IV32); 122 p1k[1] = Hi16(tsc_IV32); 123 p1k[2] = Mk16(ta[1], ta[0]); 124 p1k[3] = Mk16(ta[3], ta[2]); 125 p1k[4] = Mk16(ta[5], ta[4]); 126 127 for (i = 0; i < PHASE1_LOOP_COUNT; i++) { 128 j = 2 * (i & 1); 129 p1k[0] += tkip_S(p1k[4] ^ Mk16(tk[ 1 + j], tk[ 0 + j])); 130 p1k[1] += tkip_S(p1k[0] ^ Mk16(tk[ 5 + j], tk[ 4 + j])); 131 p1k[2] += tkip_S(p1k[1] ^ Mk16(tk[ 9 + j], tk[ 8 + j])); 132 p1k[3] += tkip_S(p1k[2] ^ Mk16(tk[13 + j], tk[12 + j])); 133 p1k[4] += tkip_S(p1k[3] ^ Mk16(tk[ 1 + j], tk[ 0 + j])) + i; 134 } 135 } 136 137 138 static void tkip_mixing_phase2(const u16 *p1k, const u8 *tk, u16 tsc_IV16, 139 u8 *rc4key) 140 { 141 u16 ppk[6]; 142 int i; 143 144 ppk[0] = p1k[0]; 145 ppk[1] = p1k[1]; 146 ppk[2] = p1k[2]; 147 ppk[3] = p1k[3]; 148 ppk[4] = p1k[4]; 149 ppk[5] = p1k[4] + tsc_IV16; 150 151 ppk[0] += tkip_S(ppk[5] ^ Mk16(tk[ 1], tk[ 0])); 152 ppk[1] += tkip_S(ppk[0] ^ Mk16(tk[ 3], tk[ 2])); 153 ppk[2] += tkip_S(ppk[1] ^ Mk16(tk[ 5], tk[ 4])); 154 ppk[3] += tkip_S(ppk[2] ^ Mk16(tk[ 7], tk[ 6])); 155 ppk[4] += tkip_S(ppk[3] ^ Mk16(tk[ 9], tk[ 8])); 156 ppk[5] += tkip_S(ppk[4] ^ Mk16(tk[11], tk[10])); 157 ppk[0] += RotR1(ppk[5] ^ Mk16(tk[13], tk[12])); 158 ppk[1] += RotR1(ppk[0] ^ Mk16(tk[15], tk[14])); 159 ppk[2] += RotR1(ppk[1]); 160 ppk[3] += RotR1(ppk[2]); 161 ppk[4] += RotR1(ppk[3]); 162 ppk[5] += RotR1(ppk[4]); 163 164 rc4key[0] = Hi8(tsc_IV16); 165 rc4key[1] = (Hi8(tsc_IV16) | 0x20) & 0x7f; 166 rc4key[2] = Lo8(tsc_IV16); 167 rc4key[3] = Lo8((ppk[5] ^ Mk16(tk[1], tk[0])) >> 1); 168 169 for (i = 0; i < 6; i++) { 170 rc4key[4 + 2 * i] = Lo8(ppk[i]); 171 rc4key[5 + 2 * i] = Hi8(ppk[i]); 172 } 173 } 174 175 176 /* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets 177 * of the IV. Returns pointer to the octet following IVs (i.e., beginning of 178 * the packet payload). */ 179 u8 * ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key, 180 u8 iv0, u8 iv1, u8 iv2) 181 { 182 *pos++ = iv0; 183 *pos++ = iv1; 184 *pos++ = iv2; 185 *pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */; 186 *pos++ = key->u.tkip.iv32 & 0xff; 187 *pos++ = (key->u.tkip.iv32 >> 8) & 0xff; 188 *pos++ = (key->u.tkip.iv32 >> 16) & 0xff; 189 *pos++ = (key->u.tkip.iv32 >> 24) & 0xff; 190 return pos; 191 } 192 193 194 void ieee80211_tkip_gen_phase1key(struct ieee80211_key *key, u8 *ta, 195 u16 *phase1key) 196 { 197 tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], 198 key->u.tkip.iv32, phase1key); 199 } 200 201 void ieee80211_tkip_gen_rc4key(struct ieee80211_key *key, u8 *ta, 202 u8 *rc4key) 203 { 204 /* Calculate per-packet key */ 205 if (key->u.tkip.iv16 == 0 || !key->u.tkip.tx_initialized) { 206 /* IV16 wrapped around - perform TKIP phase 1 */ 207 tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], 208 key->u.tkip.iv32, key->u.tkip.p1k); 209 key->u.tkip.tx_initialized = 1; 210 } 211 212 tkip_mixing_phase2(key->u.tkip.p1k, 213 &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], 214 key->u.tkip.iv16, rc4key); 215 } 216 217 /* Encrypt packet payload with TKIP using @key. @pos is a pointer to the 218 * beginning of the buffer containing payload. This payload must include 219 * headroom of eight octets for IV and Ext. IV and taildroom of four octets 220 * for ICV. @payload_len is the length of payload (_not_ including extra 221 * headroom and tailroom). @ta is the transmitter addresses. */ 222 void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm, 223 struct ieee80211_key *key, 224 u8 *pos, size_t payload_len, u8 *ta) 225 { 226 u8 rc4key[16]; 227 228 ieee80211_tkip_gen_rc4key(key, ta, rc4key); 229 pos = ieee80211_tkip_add_iv(pos, key, rc4key[0], rc4key[1], rc4key[2]); 230 ieee80211_wep_encrypt_data(tfm, rc4key, 16, pos, payload_len); 231 } 232 233 234 /* Decrypt packet payload with TKIP using @key. @pos is a pointer to the 235 * beginning of the buffer containing IEEE 802.11 header payload, i.e., 236 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the 237 * length of payload, including IV, Ext. IV, MIC, ICV. */ 238 int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm, 239 struct ieee80211_key *key, 240 u8 *payload, size_t payload_len, u8 *ta, 241 int only_iv, int queue, 242 u32 *out_iv32, u16 *out_iv16) 243 { 244 u32 iv32; 245 u32 iv16; 246 u8 rc4key[16], keyid, *pos = payload; 247 int res; 248 249 if (payload_len < 12) 250 return -1; 251 252 iv16 = (pos[0] << 8) | pos[2]; 253 keyid = pos[3]; 254 iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24); 255 pos += 8; 256 #ifdef CONFIG_TKIP_DEBUG 257 { 258 int i; 259 printk(KERN_DEBUG "TKIP decrypt: data(len=%zd)", payload_len); 260 for (i = 0; i < payload_len; i++) 261 printk(" %02x", payload[i]); 262 printk("\n"); 263 printk(KERN_DEBUG "TKIP decrypt: iv16=%04x iv32=%08x\n", 264 iv16, iv32); 265 } 266 #endif /* CONFIG_TKIP_DEBUG */ 267 268 if (!(keyid & (1 << 5))) 269 return TKIP_DECRYPT_NO_EXT_IV; 270 271 if ((keyid >> 6) != key->conf.keyidx) 272 return TKIP_DECRYPT_INVALID_KEYIDX; 273 274 if (key->u.tkip.rx_initialized[queue] && 275 (iv32 < key->u.tkip.iv32_rx[queue] || 276 (iv32 == key->u.tkip.iv32_rx[queue] && 277 iv16 <= key->u.tkip.iv16_rx[queue]))) { 278 #ifdef CONFIG_TKIP_DEBUG 279 DECLARE_MAC_BUF(mac); 280 printk(KERN_DEBUG "TKIP replay detected for RX frame from " 281 "%s (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n", 282 print_mac(mac, ta), 283 iv32, iv16, key->u.tkip.iv32_rx[queue], 284 key->u.tkip.iv16_rx[queue]); 285 #endif /* CONFIG_TKIP_DEBUG */ 286 return TKIP_DECRYPT_REPLAY; 287 } 288 289 if (only_iv) { 290 res = TKIP_DECRYPT_OK; 291 key->u.tkip.rx_initialized[queue] = 1; 292 goto done; 293 } 294 295 if (!key->u.tkip.rx_initialized[queue] || 296 key->u.tkip.iv32_rx[queue] != iv32) { 297 key->u.tkip.rx_initialized[queue] = 1; 298 /* IV16 wrapped around - perform TKIP phase 1 */ 299 tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], 300 iv32, key->u.tkip.p1k_rx[queue]); 301 #ifdef CONFIG_TKIP_DEBUG 302 { 303 int i; 304 DECLARE_MAC_BUF(mac); 305 printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%s" 306 " TK=", print_mac(mac, ta)); 307 for (i = 0; i < 16; i++) 308 printk("%02x ", 309 key->conf.key[ 310 ALG_TKIP_TEMP_ENCR_KEY + i]); 311 printk("\n"); 312 printk(KERN_DEBUG "TKIP decrypt: P1K="); 313 for (i = 0; i < 5; i++) 314 printk("%04x ", key->u.tkip.p1k_rx[queue][i]); 315 printk("\n"); 316 } 317 #endif /* CONFIG_TKIP_DEBUG */ 318 } 319 320 tkip_mixing_phase2(key->u.tkip.p1k_rx[queue], 321 &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], 322 iv16, rc4key); 323 #ifdef CONFIG_TKIP_DEBUG 324 { 325 int i; 326 printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key="); 327 for (i = 0; i < 16; i++) 328 printk("%02x ", rc4key[i]); 329 printk("\n"); 330 } 331 #endif /* CONFIG_TKIP_DEBUG */ 332 333 res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12); 334 done: 335 if (res == TKIP_DECRYPT_OK) { 336 /* 337 * Record previously received IV, will be copied into the 338 * key information after MIC verification. It is possible 339 * that we don't catch replays of fragments but that's ok 340 * because the Michael MIC verication will then fail. 341 */ 342 *out_iv32 = iv32; 343 *out_iv16 = iv16; 344 } 345 346 return res; 347 } 348 349 350