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 "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 void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf, 218 struct sk_buff *skb, enum ieee80211_tkip_key_type type, 219 u8 *outkey) 220 { 221 struct ieee80211_key *key = (struct ieee80211_key *) 222 container_of(keyconf, struct ieee80211_key, conf); 223 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 224 u8 *data = (u8 *) hdr; 225 u16 fc = le16_to_cpu(hdr->frame_control); 226 int hdr_len = ieee80211_get_hdrlen(fc); 227 u8 *ta = hdr->addr2; 228 u16 iv16; 229 u32 iv32; 230 231 iv16 = data[hdr_len] << 8; 232 iv16 += data[hdr_len + 2]; 233 iv32 = data[hdr_len + 4] | (data[hdr_len + 5] << 8) | 234 (data[hdr_len + 6] << 16) | (data[hdr_len + 7] << 24); 235 236 #ifdef CONFIG_TKIP_DEBUG 237 printk(KERN_DEBUG "TKIP encrypt: iv16 = 0x%04x, iv32 = 0x%08x\n", 238 iv16, iv32); 239 240 if (iv32 != key->u.tkip.iv32) { 241 printk(KERN_DEBUG "skb: iv32 = 0x%08x key: iv32 = 0x%08x\n", 242 iv32, key->u.tkip.iv32); 243 printk(KERN_DEBUG "Wrap around of iv16 in the middle of a " 244 "fragmented packet\n"); 245 } 246 #endif /* CONFIG_TKIP_DEBUG */ 247 248 /* Update the p1k only when the iv16 in the packet wraps around, this 249 * might occur after the wrap around of iv16 in the key in case of 250 * fragmented packets. */ 251 if (iv16 == 0 || !key->u.tkip.tx_initialized) { 252 /* IV16 wrapped around - perform TKIP phase 1 */ 253 tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], 254 iv32, key->u.tkip.p1k); 255 key->u.tkip.tx_initialized = 1; 256 } 257 258 if (type == IEEE80211_TKIP_P1_KEY) { 259 memcpy(outkey, key->u.tkip.p1k, sizeof(u16) * 5); 260 return; 261 } 262 263 tkip_mixing_phase2(key->u.tkip.p1k, 264 &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], iv16, outkey); 265 } 266 EXPORT_SYMBOL(ieee80211_get_tkip_key); 267 268 /* Encrypt packet payload with TKIP using @key. @pos is a pointer to the 269 * beginning of the buffer containing payload. This payload must include 270 * headroom of eight octets for IV and Ext. IV and taildroom of four octets 271 * for ICV. @payload_len is the length of payload (_not_ including extra 272 * headroom and tailroom). @ta is the transmitter addresses. */ 273 void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm, 274 struct ieee80211_key *key, 275 u8 *pos, size_t payload_len, u8 *ta) 276 { 277 u8 rc4key[16]; 278 279 ieee80211_tkip_gen_rc4key(key, ta, rc4key); 280 pos = ieee80211_tkip_add_iv(pos, key, rc4key[0], rc4key[1], rc4key[2]); 281 ieee80211_wep_encrypt_data(tfm, rc4key, 16, pos, payload_len); 282 } 283 284 285 /* Decrypt packet payload with TKIP using @key. @pos is a pointer to the 286 * beginning of the buffer containing IEEE 802.11 header payload, i.e., 287 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the 288 * length of payload, including IV, Ext. IV, MIC, ICV. */ 289 int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm, 290 struct ieee80211_key *key, 291 u8 *payload, size_t payload_len, u8 *ta, 292 u8 *ra, int only_iv, int queue, 293 u32 *out_iv32, u16 *out_iv16) 294 { 295 u32 iv32; 296 u32 iv16; 297 u8 rc4key[16], keyid, *pos = payload; 298 int res; 299 300 if (payload_len < 12) 301 return -1; 302 303 iv16 = (pos[0] << 8) | pos[2]; 304 keyid = pos[3]; 305 iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24); 306 pos += 8; 307 #ifdef CONFIG_TKIP_DEBUG 308 { 309 int i; 310 printk(KERN_DEBUG "TKIP decrypt: data(len=%zd)", payload_len); 311 for (i = 0; i < payload_len; i++) 312 printk(" %02x", payload[i]); 313 printk("\n"); 314 printk(KERN_DEBUG "TKIP decrypt: iv16=%04x iv32=%08x\n", 315 iv16, iv32); 316 } 317 #endif /* CONFIG_TKIP_DEBUG */ 318 319 if (!(keyid & (1 << 5))) 320 return TKIP_DECRYPT_NO_EXT_IV; 321 322 if ((keyid >> 6) != key->conf.keyidx) 323 return TKIP_DECRYPT_INVALID_KEYIDX; 324 325 if (key->u.tkip.rx_initialized[queue] && 326 (iv32 < key->u.tkip.iv32_rx[queue] || 327 (iv32 == key->u.tkip.iv32_rx[queue] && 328 iv16 <= key->u.tkip.iv16_rx[queue]))) { 329 #ifdef CONFIG_TKIP_DEBUG 330 DECLARE_MAC_BUF(mac); 331 printk(KERN_DEBUG "TKIP replay detected for RX frame from " 332 "%s (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n", 333 print_mac(mac, ta), 334 iv32, iv16, key->u.tkip.iv32_rx[queue], 335 key->u.tkip.iv16_rx[queue]); 336 #endif /* CONFIG_TKIP_DEBUG */ 337 return TKIP_DECRYPT_REPLAY; 338 } 339 340 if (only_iv) { 341 res = TKIP_DECRYPT_OK; 342 key->u.tkip.rx_initialized[queue] = 1; 343 goto done; 344 } 345 346 if (!key->u.tkip.rx_initialized[queue] || 347 key->u.tkip.iv32_rx[queue] != iv32) { 348 key->u.tkip.rx_initialized[queue] = 1; 349 /* IV16 wrapped around - perform TKIP phase 1 */ 350 tkip_mixing_phase1(ta, &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], 351 iv32, key->u.tkip.p1k_rx[queue]); 352 #ifdef CONFIG_TKIP_DEBUG 353 { 354 int i; 355 DECLARE_MAC_BUF(mac); 356 printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%s" 357 " TK=", print_mac(mac, ta)); 358 for (i = 0; i < 16; i++) 359 printk("%02x ", 360 key->conf.key[ 361 ALG_TKIP_TEMP_ENCR_KEY + i]); 362 printk("\n"); 363 printk(KERN_DEBUG "TKIP decrypt: P1K="); 364 for (i = 0; i < 5; i++) 365 printk("%04x ", key->u.tkip.p1k_rx[queue][i]); 366 printk("\n"); 367 } 368 #endif /* CONFIG_TKIP_DEBUG */ 369 if (key->local->ops->update_tkip_key && 370 key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) { 371 u8 bcast[ETH_ALEN] = 372 {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; 373 u8 *sta_addr = key->sta->addr; 374 375 if (is_multicast_ether_addr(ra)) 376 sta_addr = bcast; 377 378 key->local->ops->update_tkip_key( 379 local_to_hw(key->local), &key->conf, 380 sta_addr, iv32, key->u.tkip.p1k_rx[queue]); 381 } 382 } 383 384 tkip_mixing_phase2(key->u.tkip.p1k_rx[queue], 385 &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY], 386 iv16, rc4key); 387 #ifdef CONFIG_TKIP_DEBUG 388 { 389 int i; 390 printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key="); 391 for (i = 0; i < 16; i++) 392 printk("%02x ", rc4key[i]); 393 printk("\n"); 394 } 395 #endif /* CONFIG_TKIP_DEBUG */ 396 397 res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12); 398 done: 399 if (res == TKIP_DECRYPT_OK) { 400 /* 401 * Record previously received IV, will be copied into the 402 * key information after MIC verification. It is possible 403 * that we don't catch replays of fragments but that's ok 404 * because the Michael MIC verication will then fail. 405 */ 406 *out_iv32 = iv32; 407 *out_iv16 = iv16; 408 } 409 410 return res; 411 } 412 413 414