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 <linux/export.h> 14 #include <asm/unaligned.h> 15 16 #include <net/mac80211.h> 17 #include "driver-ops.h" 18 #include "key.h" 19 #include "tkip.h" 20 #include "wep.h" 21 22 #define PHASE1_LOOP_COUNT 8 23 24 /* 25 * 2-byte by 2-byte subset of the full AES S-box table; second part of this 26 * table is identical to first part but byte-swapped 27 */ 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 static u16 tkipS(u16 val) 65 { 66 return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]); 67 } 68 69 static u8 *write_tkip_iv(u8 *pos, u16 iv16) 70 { 71 *pos++ = iv16 >> 8; 72 *pos++ = ((iv16 >> 8) | 0x20) & 0x7f; 73 *pos++ = iv16 & 0xFF; 74 return pos; 75 } 76 77 /* 78 * P1K := Phase1(TA, TK, TSC) 79 * TA = transmitter address (48 bits) 80 * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits) 81 * TSC = TKIP sequence counter (48 bits, only 32 msb bits used) 82 * P1K: 80 bits 83 */ 84 static void tkip_mixing_phase1(const u8 *tk, struct tkip_ctx *ctx, 85 const u8 *ta, u32 tsc_IV32) 86 { 87 int i, j; 88 u16 *p1k = ctx->p1k; 89 90 p1k[0] = tsc_IV32 & 0xFFFF; 91 p1k[1] = tsc_IV32 >> 16; 92 p1k[2] = get_unaligned_le16(ta + 0); 93 p1k[3] = get_unaligned_le16(ta + 2); 94 p1k[4] = get_unaligned_le16(ta + 4); 95 96 for (i = 0; i < PHASE1_LOOP_COUNT; i++) { 97 j = 2 * (i & 1); 98 p1k[0] += tkipS(p1k[4] ^ get_unaligned_le16(tk + 0 + j)); 99 p1k[1] += tkipS(p1k[0] ^ get_unaligned_le16(tk + 4 + j)); 100 p1k[2] += tkipS(p1k[1] ^ get_unaligned_le16(tk + 8 + j)); 101 p1k[3] += tkipS(p1k[2] ^ get_unaligned_le16(tk + 12 + j)); 102 p1k[4] += tkipS(p1k[3] ^ get_unaligned_le16(tk + 0 + j)) + i; 103 } 104 ctx->state = TKIP_STATE_PHASE1_DONE; 105 ctx->p1k_iv32 = tsc_IV32; 106 } 107 108 static void tkip_mixing_phase2(const u8 *tk, struct tkip_ctx *ctx, 109 u16 tsc_IV16, u8 *rc4key) 110 { 111 u16 ppk[6]; 112 const u16 *p1k = ctx->p1k; 113 int i; 114 115 ppk[0] = p1k[0]; 116 ppk[1] = p1k[1]; 117 ppk[2] = p1k[2]; 118 ppk[3] = p1k[3]; 119 ppk[4] = p1k[4]; 120 ppk[5] = p1k[4] + tsc_IV16; 121 122 ppk[0] += tkipS(ppk[5] ^ get_unaligned_le16(tk + 0)); 123 ppk[1] += tkipS(ppk[0] ^ get_unaligned_le16(tk + 2)); 124 ppk[2] += tkipS(ppk[1] ^ get_unaligned_le16(tk + 4)); 125 ppk[3] += tkipS(ppk[2] ^ get_unaligned_le16(tk + 6)); 126 ppk[4] += tkipS(ppk[3] ^ get_unaligned_le16(tk + 8)); 127 ppk[5] += tkipS(ppk[4] ^ get_unaligned_le16(tk + 10)); 128 ppk[0] += ror16(ppk[5] ^ get_unaligned_le16(tk + 12), 1); 129 ppk[1] += ror16(ppk[0] ^ get_unaligned_le16(tk + 14), 1); 130 ppk[2] += ror16(ppk[1], 1); 131 ppk[3] += ror16(ppk[2], 1); 132 ppk[4] += ror16(ppk[3], 1); 133 ppk[5] += ror16(ppk[4], 1); 134 135 rc4key = write_tkip_iv(rc4key, tsc_IV16); 136 *rc4key++ = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF; 137 138 for (i = 0; i < 6; i++) 139 put_unaligned_le16(ppk[i], rc4key + 2 * i); 140 } 141 142 /* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets 143 * of the IV. Returns pointer to the octet following IVs (i.e., beginning of 144 * the packet payload). */ 145 u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key) 146 { 147 lockdep_assert_held(&key->u.tkip.txlock); 148 149 pos = write_tkip_iv(pos, key->u.tkip.tx.iv16); 150 *pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */; 151 put_unaligned_le32(key->u.tkip.tx.iv32, pos); 152 return pos + 4; 153 } 154 155 static void ieee80211_compute_tkip_p1k(struct ieee80211_key *key, u32 iv32) 156 { 157 struct ieee80211_sub_if_data *sdata = key->sdata; 158 struct tkip_ctx *ctx = &key->u.tkip.tx; 159 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; 160 161 lockdep_assert_held(&key->u.tkip.txlock); 162 163 /* 164 * Update the P1K when the IV32 is different from the value it 165 * had when we last computed it (or when not initialised yet). 166 * This might flip-flop back and forth if packets are processed 167 * out-of-order due to the different ACs, but then we have to 168 * just compute the P1K more often. 169 */ 170 if (ctx->p1k_iv32 != iv32 || ctx->state == TKIP_STATE_NOT_INIT) 171 tkip_mixing_phase1(tk, ctx, sdata->vif.addr, iv32); 172 } 173 174 void ieee80211_get_tkip_p1k_iv(struct ieee80211_key_conf *keyconf, 175 u32 iv32, u16 *p1k) 176 { 177 struct ieee80211_key *key = (struct ieee80211_key *) 178 container_of(keyconf, struct ieee80211_key, conf); 179 struct tkip_ctx *ctx = &key->u.tkip.tx; 180 181 spin_lock_bh(&key->u.tkip.txlock); 182 ieee80211_compute_tkip_p1k(key, iv32); 183 memcpy(p1k, ctx->p1k, sizeof(ctx->p1k)); 184 spin_unlock_bh(&key->u.tkip.txlock); 185 } 186 EXPORT_SYMBOL(ieee80211_get_tkip_p1k_iv); 187 188 void ieee80211_get_tkip_rx_p1k(struct ieee80211_key_conf *keyconf, 189 const u8 *ta, u32 iv32, u16 *p1k) 190 { 191 const u8 *tk = &keyconf->key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; 192 struct tkip_ctx ctx; 193 194 tkip_mixing_phase1(tk, &ctx, ta, iv32); 195 memcpy(p1k, ctx.p1k, sizeof(ctx.p1k)); 196 } 197 EXPORT_SYMBOL(ieee80211_get_tkip_rx_p1k); 198 199 void ieee80211_get_tkip_p2k(struct ieee80211_key_conf *keyconf, 200 struct sk_buff *skb, u8 *p2k) 201 { 202 struct ieee80211_key *key = (struct ieee80211_key *) 203 container_of(keyconf, struct ieee80211_key, conf); 204 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; 205 struct tkip_ctx *ctx = &key->u.tkip.tx; 206 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; 207 const u8 *data = (u8 *)hdr + ieee80211_hdrlen(hdr->frame_control); 208 u32 iv32 = get_unaligned_le32(&data[4]); 209 u16 iv16 = data[2] | (data[0] << 8); 210 211 spin_lock(&key->u.tkip.txlock); 212 ieee80211_compute_tkip_p1k(key, iv32); 213 tkip_mixing_phase2(tk, ctx, iv16, p2k); 214 spin_unlock(&key->u.tkip.txlock); 215 } 216 EXPORT_SYMBOL(ieee80211_get_tkip_p2k); 217 218 /* 219 * Encrypt packet payload with TKIP using @key. @pos is a pointer to the 220 * beginning of the buffer containing payload. This payload must include 221 * the IV/Ext.IV and space for (taildroom) four octets for ICV. 222 * @payload_len is the length of payload (_not_ including IV/ICV length). 223 * @ta is the transmitter addresses. 224 */ 225 int ieee80211_tkip_encrypt_data(struct crypto_cipher *tfm, 226 struct ieee80211_key *key, 227 struct sk_buff *skb, 228 u8 *payload, size_t payload_len) 229 { 230 u8 rc4key[16]; 231 232 ieee80211_get_tkip_p2k(&key->conf, skb, rc4key); 233 234 return ieee80211_wep_encrypt_data(tfm, rc4key, 16, 235 payload, payload_len); 236 } 237 238 /* Decrypt packet payload with TKIP using @key. @pos is a pointer to the 239 * beginning of the buffer containing IEEE 802.11 header payload, i.e., 240 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the 241 * length of payload, including IV, Ext. IV, MIC, ICV. */ 242 int ieee80211_tkip_decrypt_data(struct crypto_cipher *tfm, 243 struct ieee80211_key *key, 244 u8 *payload, size_t payload_len, u8 *ta, 245 u8 *ra, int only_iv, int queue, 246 u32 *out_iv32, u16 *out_iv16) 247 { 248 u32 iv32; 249 u32 iv16; 250 u8 rc4key[16], keyid, *pos = payload; 251 int res; 252 const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; 253 254 if (payload_len < 12) 255 return -1; 256 257 iv16 = (pos[0] << 8) | pos[2]; 258 keyid = pos[3]; 259 iv32 = get_unaligned_le32(pos + 4); 260 pos += 8; 261 262 if (!(keyid & (1 << 5))) 263 return TKIP_DECRYPT_NO_EXT_IV; 264 265 if ((keyid >> 6) != key->conf.keyidx) 266 return TKIP_DECRYPT_INVALID_KEYIDX; 267 268 if (key->u.tkip.rx[queue].state != TKIP_STATE_NOT_INIT && 269 (iv32 < key->u.tkip.rx[queue].iv32 || 270 (iv32 == key->u.tkip.rx[queue].iv32 && 271 iv16 <= key->u.tkip.rx[queue].iv16))) 272 return TKIP_DECRYPT_REPLAY; 273 274 if (only_iv) { 275 res = TKIP_DECRYPT_OK; 276 key->u.tkip.rx[queue].state = TKIP_STATE_PHASE1_HW_UPLOADED; 277 goto done; 278 } 279 280 if (key->u.tkip.rx[queue].state == TKIP_STATE_NOT_INIT || 281 key->u.tkip.rx[queue].iv32 != iv32) { 282 /* IV16 wrapped around - perform TKIP phase 1 */ 283 tkip_mixing_phase1(tk, &key->u.tkip.rx[queue], ta, iv32); 284 } 285 if (key->local->ops->update_tkip_key && 286 key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE && 287 key->u.tkip.rx[queue].state != TKIP_STATE_PHASE1_HW_UPLOADED) { 288 struct ieee80211_sub_if_data *sdata = key->sdata; 289 290 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) 291 sdata = container_of(key->sdata->bss, 292 struct ieee80211_sub_if_data, u.ap); 293 drv_update_tkip_key(key->local, sdata, &key->conf, key->sta, 294 iv32, key->u.tkip.rx[queue].p1k); 295 key->u.tkip.rx[queue].state = TKIP_STATE_PHASE1_HW_UPLOADED; 296 } 297 298 tkip_mixing_phase2(tk, &key->u.tkip.rx[queue], iv16, rc4key); 299 300 res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12); 301 done: 302 if (res == TKIP_DECRYPT_OK) { 303 /* 304 * Record previously received IV, will be copied into the 305 * key information after MIC verification. It is possible 306 * that we don't catch replays of fragments but that's ok 307 * because the Michael MIC verication will then fail. 308 */ 309 *out_iv32 = iv32; 310 *out_iv16 = iv16; 311 } 312 313 return res; 314 } 315