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 #include <linux/kernel.h> 10 #include <linux/bitops.h> 11 #include <linux/types.h> 12 #include <linux/netdevice.h> 13 #include <asm/unaligned.h> 14 15 #include <net/mac80211.h> 16 #include "driver-ops.h" 17 #include "key.h" 18 #include "tkip.h" 19 #include "wep.h" 20 21 #define PHASE1_LOOP_COUNT 8 22 23 /* 24 * 2-byte by 2-byte subset of the full AES S-box table; second part of this 25 * table is identical to first part but byte-swapped 26 */ 27 static const u16 tkip_sbox[256] = 28 { 29 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154, 30 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A, 31 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B, 32 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B, 33 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F, 34 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F, 35 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5, 36 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F, 37 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB, 38 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397, 39 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED, 40 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A, 41 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194, 42 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3, 43 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104, 44 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D, 45 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39, 46 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695, 47 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83, 48 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76, 49 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4, 50 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B, 51 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0, 52 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018, 53 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751, 54 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85, 55 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12, 56 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9, 57 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7, 58 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A, 59 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8, 60 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A, 61 }; 62 63 static u16 tkipS(u16 val) 64 { 65 return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]); 66 } 67 68 static u8 *write_tkip_iv(u8 *pos, u16 iv16) 69 { 70 *pos++ = iv16 >> 8; 71 *pos++ = ((iv16 >> 8) | 0x20) & 0x7f; 72 *pos++ = iv16 & 0xFF; 73 return pos; 74 } 75 76 /* 77 * P1K := Phase1(TA, TK, TSC) 78 * TA = transmitter address (48 bits) 79 * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits) 80 * TSC = TKIP sequence counter (48 bits, only 32 msb bits used) 81 * P1K: 80 bits 82 */ 83 static void tkip_mixing_phase1(const u8 *tk, struct tkip_ctx *ctx, 84 const u8 *ta, u32 tsc_IV32) 85 { 86 int i, j; 87 u16 *p1k = ctx->p1k; 88 89 p1k[0] = tsc_IV32 & 0xFFFF; 90 p1k[1] = tsc_IV32 >> 16; 91 p1k[2] = get_unaligned_le16(ta + 0); 92 p1k[3] = get_unaligned_le16(ta + 2); 93 p1k[4] = get_unaligned_le16(ta + 4); 94 95 for (i = 0; i < PHASE1_LOOP_COUNT; i++) { 96 j = 2 * (i & 1); 97 p1k[0] += tkipS(p1k[4] ^ get_unaligned_le16(tk + 0 + j)); 98 p1k[1] += tkipS(p1k[0] ^ get_unaligned_le16(tk + 4 + j)); 99 p1k[2] += tkipS(p1k[1] ^ get_unaligned_le16(tk + 8 + j)); 100 p1k[3] += tkipS(p1k[2] ^ get_unaligned_le16(tk + 12 + j)); 101 p1k[4] += tkipS(p1k[3] ^ get_unaligned_le16(tk + 0 + j)) + i; 102 } 103 ctx->state = TKIP_STATE_PHASE1_DONE; 104 } 105 106 static void tkip_mixing_phase2(const u8 *tk, struct tkip_ctx *ctx, 107 u16 tsc_IV16, u8 *rc4key) 108 { 109 u16 ppk[6]; 110 const u16 *p1k = ctx->p1k; 111 int i; 112 113 ppk[0] = p1k[0]; 114 ppk[1] = p1k[1]; 115 ppk[2] = p1k[2]; 116 ppk[3] = p1k[3]; 117 ppk[4] = p1k[4]; 118 ppk[5] = p1k[4] + tsc_IV16; 119 120 ppk[0] += tkipS(ppk[5] ^ get_unaligned_le16(tk + 0)); 121 ppk[1] += tkipS(ppk[0] ^ get_unaligned_le16(tk + 2)); 122 ppk[2] += tkipS(ppk[1] ^ get_unaligned_le16(tk + 4)); 123 ppk[3] += tkipS(ppk[2] ^ get_unaligned_le16(tk + 6)); 124 ppk[4] += tkipS(ppk[3] ^ get_unaligned_le16(tk + 8)); 125 ppk[5] += tkipS(ppk[4] ^ get_unaligned_le16(tk + 10)); 126 ppk[0] += ror16(ppk[5] ^ get_unaligned_le16(tk + 12), 1); 127 ppk[1] += ror16(ppk[0] ^ get_unaligned_le16(tk + 14), 1); 128 ppk[2] += ror16(ppk[1], 1); 129 ppk[3] += ror16(ppk[2], 1); 130 ppk[4] += ror16(ppk[3], 1); 131 ppk[5] += ror16(ppk[4], 1); 132 133 rc4key = write_tkip_iv(rc4key, tsc_IV16); 134 *rc4key++ = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF; 135 136 for (i = 0; i < 6; i++) 137 put_unaligned_le16(ppk[i], rc4key + 2 * i); 138 } 139 140 /* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets 141 * of the IV. Returns pointer to the octet following IVs (i.e., beginning of 142 * the packet payload). */ 143 u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key, u16 iv16) 144 { 145 pos = write_tkip_iv(pos, iv16); 146 *pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */; 147 put_unaligned_le32(key->u.tkip.tx.iv32, pos); 148 return pos + 4; 149 } 150 151 void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf, 152 struct sk_buff *skb, enum ieee80211_tkip_key_type type, 153 u8 *outkey) 154 { 155 struct ieee80211_key *key = (struct ieee80211_key *) 156 container_of(keyconf, struct ieee80211_key, conf); 157 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 158 u8 *data; 159 const u8 *tk; 160 struct tkip_ctx *ctx; 161 u16 iv16; 162 u32 iv32; 163 164 data = (u8 *)hdr + ieee80211_hdrlen(hdr->frame_control); 165 iv16 = data[2] | (data[0] << 8); 166 iv32 = get_unaligned_le32(&data[4]); 167 168 tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; 169 ctx = &key->u.tkip.tx; 170 171 #ifdef CONFIG_MAC80211_TKIP_DEBUG 172 printk(KERN_DEBUG "TKIP encrypt: iv16 = 0x%04x, iv32 = 0x%08x\n", 173 iv16, iv32); 174 175 if (iv32 != ctx->iv32) { 176 printk(KERN_DEBUG "skb: iv32 = 0x%08x key: iv32 = 0x%08x\n", 177 iv32, ctx->iv32); 178 printk(KERN_DEBUG "Wrap around of iv16 in the middle of a " 179 "fragmented packet\n"); 180 } 181 #endif 182 183 /* Update the p1k only when the iv16 in the packet wraps around, this 184 * might occur after the wrap around of iv16 in the key in case of 185 * fragmented packets. */ 186 if (iv16 == 0 || ctx->state == TKIP_STATE_NOT_INIT) 187 tkip_mixing_phase1(tk, ctx, hdr->addr2, iv32); 188 189 if (type == IEEE80211_TKIP_P1_KEY) { 190 memcpy(outkey, ctx->p1k, sizeof(u16) * 5); 191 return; 192 } 193 194 tkip_mixing_phase2(tk, ctx, iv16, outkey); 195 } 196 EXPORT_SYMBOL(ieee80211_get_tkip_key); 197 198 /* 199 * Encrypt packet payload with TKIP using @key. @pos is a pointer to the 200 * beginning of the buffer containing payload. This payload must include 201 * the IV/Ext.IV and space for (taildroom) four octets for ICV. 202 * @payload_len is the length of payload (_not_ including IV/ICV length). 203 * @ta is the transmitter addresses. 204 */ 205 void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm, 206 struct ieee80211_key *key, 207 u8 *pos, size_t payload_len, u8 *ta) 208 { 209 u8 rc4key[16]; 210 struct tkip_ctx *ctx = &key->u.tkip.tx; 211 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; 212 213 /* Calculate per-packet key */ 214 if (ctx->iv16 == 0 || ctx->state == TKIP_STATE_NOT_INIT) 215 tkip_mixing_phase1(tk, ctx, ta, ctx->iv32); 216 217 tkip_mixing_phase2(tk, ctx, ctx->iv16, rc4key); 218 219 ieee80211_wep_encrypt_data(tfm, rc4key, 16, pos, payload_len); 220 } 221 222 /* Decrypt packet payload with TKIP using @key. @pos is a pointer to the 223 * beginning of the buffer containing IEEE 802.11 header payload, i.e., 224 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the 225 * length of payload, including IV, Ext. IV, MIC, ICV. */ 226 int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm, 227 struct ieee80211_key *key, 228 u8 *payload, size_t payload_len, u8 *ta, 229 u8 *ra, int only_iv, int queue, 230 u32 *out_iv32, u16 *out_iv16) 231 { 232 u32 iv32; 233 u32 iv16; 234 u8 rc4key[16], keyid, *pos = payload; 235 int res; 236 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; 237 238 if (payload_len < 12) 239 return -1; 240 241 iv16 = (pos[0] << 8) | pos[2]; 242 keyid = pos[3]; 243 iv32 = get_unaligned_le32(pos + 4); 244 pos += 8; 245 #ifdef CONFIG_MAC80211_TKIP_DEBUG 246 { 247 int i; 248 printk(KERN_DEBUG "TKIP decrypt: data(len=%zd)", payload_len); 249 for (i = 0; i < payload_len; i++) 250 printk(" %02x", payload[i]); 251 printk("\n"); 252 printk(KERN_DEBUG "TKIP decrypt: iv16=%04x iv32=%08x\n", 253 iv16, iv32); 254 } 255 #endif 256 257 if (!(keyid & (1 << 5))) 258 return TKIP_DECRYPT_NO_EXT_IV; 259 260 if ((keyid >> 6) != key->conf.keyidx) 261 return TKIP_DECRYPT_INVALID_KEYIDX; 262 263 if (key->u.tkip.rx[queue].state != TKIP_STATE_NOT_INIT && 264 (iv32 < key->u.tkip.rx[queue].iv32 || 265 (iv32 == key->u.tkip.rx[queue].iv32 && 266 iv16 <= key->u.tkip.rx[queue].iv16))) { 267 #ifdef CONFIG_MAC80211_TKIP_DEBUG 268 printk(KERN_DEBUG "TKIP replay detected for RX frame from " 269 "%pM (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n", 270 ta, 271 iv32, iv16, key->u.tkip.rx[queue].iv32, 272 key->u.tkip.rx[queue].iv16); 273 #endif 274 return TKIP_DECRYPT_REPLAY; 275 } 276 277 if (only_iv) { 278 res = TKIP_DECRYPT_OK; 279 key->u.tkip.rx[queue].state = TKIP_STATE_PHASE1_HW_UPLOADED; 280 goto done; 281 } 282 283 if (key->u.tkip.rx[queue].state == TKIP_STATE_NOT_INIT || 284 key->u.tkip.rx[queue].iv32 != iv32) { 285 /* IV16 wrapped around - perform TKIP phase 1 */ 286 tkip_mixing_phase1(tk, &key->u.tkip.rx[queue], ta, iv32); 287 #ifdef CONFIG_MAC80211_TKIP_DEBUG 288 { 289 int i; 290 u8 key_offset = NL80211_TKIP_DATA_OFFSET_ENCR_KEY; 291 printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%pM" 292 " TK=", ta); 293 for (i = 0; i < 16; i++) 294 printk("%02x ", 295 key->conf.key[key_offset + i]); 296 printk("\n"); 297 printk(KERN_DEBUG "TKIP decrypt: P1K="); 298 for (i = 0; i < 5; i++) 299 printk("%04x ", key->u.tkip.rx[queue].p1k[i]); 300 printk("\n"); 301 } 302 #endif 303 } 304 if (key->local->ops->update_tkip_key && 305 key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE && 306 key->u.tkip.rx[queue].state != TKIP_STATE_PHASE1_HW_UPLOADED) { 307 struct ieee80211_sub_if_data *sdata = key->sdata; 308 309 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) 310 sdata = container_of(key->sdata->bss, 311 struct ieee80211_sub_if_data, u.ap); 312 drv_update_tkip_key(key->local, sdata, &key->conf, key->sta, 313 iv32, key->u.tkip.rx[queue].p1k); 314 key->u.tkip.rx[queue].state = TKIP_STATE_PHASE1_HW_UPLOADED; 315 } 316 317 tkip_mixing_phase2(tk, &key->u.tkip.rx[queue], iv16, rc4key); 318 #ifdef CONFIG_MAC80211_TKIP_DEBUG 319 { 320 int i; 321 printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key="); 322 for (i = 0; i < 16; i++) 323 printk("%02x ", rc4key[i]); 324 printk("\n"); 325 } 326 #endif 327 328 res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12); 329 done: 330 if (res == TKIP_DECRYPT_OK) { 331 /* 332 * Record previously received IV, will be copied into the 333 * key information after MIC verification. It is possible 334 * that we don't catch replays of fragments but that's ok 335 * because the Michael MIC verication will then fail. 336 */ 337 *out_iv32 = iv32; 338 *out_iv16 = iv16; 339 } 340 341 return res; 342 } 343