tkip.c revision 3c83809917dce9bbd880f6b08edc2d0ccac14a25
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 "key.h" 17#include "tkip.h" 18#include "wep.h" 19 20#define PHASE1_LOOP_COUNT 8 21 22/* 23 * 2-byte by 2-byte subset of the full AES S-box table; second part of this 24 * table is identical to first part but byte-swapped 25 */ 26static const u16 tkip_sbox[256] = 27{ 28 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154, 29 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A, 30 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B, 31 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B, 32 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F, 33 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F, 34 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5, 35 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F, 36 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB, 37 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397, 38 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED, 39 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A, 40 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194, 41 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3, 42 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104, 43 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D, 44 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39, 45 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695, 46 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83, 47 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76, 48 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4, 49 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B, 50 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0, 51 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018, 52 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751, 53 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85, 54 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12, 55 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9, 56 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7, 57 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A, 58 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8, 59 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A, 60}; 61 62static u16 tkipS(u16 val) 63{ 64 return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]); 65} 66 67/* 68 * P1K := Phase1(TA, TK, TSC) 69 * TA = transmitter address (48 bits) 70 * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits) 71 * TSC = TKIP sequence counter (48 bits, only 32 msb bits used) 72 * P1K: 80 bits 73 */ 74static void tkip_mixing_phase1(struct ieee80211_key *key, const u8 *ta, 75 struct tkip_ctx *ctx, u32 tsc_IV32) 76{ 77 int i, j; 78 const u8 *tk = &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY]; 79 u16 *p1k = ctx->p1k; 80 81 p1k[0] = tsc_IV32 & 0xFFFF; 82 p1k[1] = tsc_IV32 >> 16; 83 p1k[2] = get_unaligned_le16(ta + 0); 84 p1k[3] = get_unaligned_le16(ta + 2); 85 p1k[4] = get_unaligned_le16(ta + 4); 86 87 for (i = 0; i < PHASE1_LOOP_COUNT; i++) { 88 j = 2 * (i & 1); 89 p1k[0] += tkipS(p1k[4] ^ get_unaligned_le16(tk + 0 + j)); 90 p1k[1] += tkipS(p1k[0] ^ get_unaligned_le16(tk + 4 + j)); 91 p1k[2] += tkipS(p1k[1] ^ get_unaligned_le16(tk + 8 + j)); 92 p1k[3] += tkipS(p1k[2] ^ get_unaligned_le16(tk + 12 + j)); 93 p1k[4] += tkipS(p1k[3] ^ get_unaligned_le16(tk + 0 + j)) + i; 94 } 95 ctx->initialized = 1; 96} 97 98static void tkip_mixing_phase2(struct ieee80211_key *key, struct tkip_ctx *ctx, 99 u16 tsc_IV16, u8 *rc4key) 100{ 101 u16 ppk[6]; 102 const u16 *p1k = ctx->p1k; 103 const u8 *tk = &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY]; 104 int i; 105 106 ppk[0] = p1k[0]; 107 ppk[1] = p1k[1]; 108 ppk[2] = p1k[2]; 109 ppk[3] = p1k[3]; 110 ppk[4] = p1k[4]; 111 ppk[5] = p1k[4] + tsc_IV16; 112 113 ppk[0] += tkipS(ppk[5] ^ get_unaligned_le16(tk + 0)); 114 ppk[1] += tkipS(ppk[0] ^ get_unaligned_le16(tk + 2)); 115 ppk[2] += tkipS(ppk[1] ^ get_unaligned_le16(tk + 4)); 116 ppk[3] += tkipS(ppk[2] ^ get_unaligned_le16(tk + 6)); 117 ppk[4] += tkipS(ppk[3] ^ get_unaligned_le16(tk + 8)); 118 ppk[5] += tkipS(ppk[4] ^ get_unaligned_le16(tk + 10)); 119 ppk[0] += ror16(ppk[5] ^ get_unaligned_le16(tk + 12), 1); 120 ppk[1] += ror16(ppk[0] ^ get_unaligned_le16(tk + 14), 1); 121 ppk[2] += ror16(ppk[1], 1); 122 ppk[3] += ror16(ppk[2], 1); 123 ppk[4] += ror16(ppk[3], 1); 124 ppk[5] += ror16(ppk[4], 1); 125 126 rc4key[0] = tsc_IV16 >> 8; 127 rc4key[1] = ((tsc_IV16 >> 8) | 0x20) & 0x7f; 128 rc4key[2] = tsc_IV16 & 0xFF; 129 rc4key[3] = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF; 130 131 rc4key += 4; 132 for (i = 0; i < 6; i++) 133 put_unaligned_le16(ppk[i], rc4key + 2 * i); 134} 135 136/* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets 137 * of the IV. Returns pointer to the octet following IVs (i.e., beginning of 138 * the packet payload). */ 139u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key, 140 u8 iv0, u8 iv1, u8 iv2) 141{ 142 *pos++ = iv0; 143 *pos++ = iv1; 144 *pos++ = iv2; 145 *pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */; 146 put_unaligned_le32(key->u.tkip.tx.iv32, pos); 147 return pos + 4; 148} 149 150static void ieee80211_tkip_gen_rc4key(struct ieee80211_key *key, u8 *ta, 151 u8 *rc4key) 152{ 153 /* Calculate per-packet key */ 154 if (key->u.tkip.tx.iv16 == 0 || !key->u.tkip.tx.initialized) 155 tkip_mixing_phase1(key, ta, &key->u.tkip.tx, key->u.tkip.tx.iv32); 156 157 tkip_mixing_phase2(key, &key->u.tkip.tx, key->u.tkip.tx.iv16, rc4key); 158} 159 160void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf, 161 struct sk_buff *skb, enum ieee80211_tkip_key_type type, 162 u8 *outkey) 163{ 164 struct ieee80211_key *key = (struct ieee80211_key *) 165 container_of(keyconf, struct ieee80211_key, conf); 166 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 167 u8 *data = (u8 *) hdr; 168 u16 fc = le16_to_cpu(hdr->frame_control); 169 int hdr_len = ieee80211_get_hdrlen(fc); 170 u8 *ta = hdr->addr2; 171 u16 iv16; 172 u32 iv32; 173 174 iv16 = data[hdr_len + 2] | (data[hdr_len] << 8); 175 iv32 = get_unaligned_le32(data + hdr_len + 4); 176 177#ifdef CONFIG_TKIP_DEBUG 178 printk(KERN_DEBUG "TKIP encrypt: iv16 = 0x%04x, iv32 = 0x%08x\n", 179 iv16, iv32); 180 181 if (iv32 != key->u.tkip.tx.iv32) { 182 printk(KERN_DEBUG "skb: iv32 = 0x%08x key: iv32 = 0x%08x\n", 183 iv32, key->u.tkip.tx.iv32); 184 printk(KERN_DEBUG "Wrap around of iv16 in the middle of a " 185 "fragmented packet\n"); 186 } 187#endif /* CONFIG_TKIP_DEBUG */ 188 189 /* Update the p1k only when the iv16 in the packet wraps around, this 190 * might occur after the wrap around of iv16 in the key in case of 191 * fragmented packets. */ 192 if (iv16 == 0 || !key->u.tkip.tx.initialized) 193 tkip_mixing_phase1(key, ta, &key->u.tkip.tx, iv32); 194 195 if (type == IEEE80211_TKIP_P1_KEY) { 196 memcpy(outkey, key->u.tkip.tx.p1k, sizeof(u16) * 5); 197 return; 198 } 199 200 tkip_mixing_phase2(key, &key->u.tkip.tx, iv16, outkey); 201} 202EXPORT_SYMBOL(ieee80211_get_tkip_key); 203 204/* Encrypt packet payload with TKIP using @key. @pos is a pointer to the 205 * beginning of the buffer containing payload. This payload must include 206 * headroom of eight octets for IV and Ext. IV and taildroom of four octets 207 * for ICV. @payload_len is the length of payload (_not_ including extra 208 * headroom and tailroom). @ta is the transmitter addresses. */ 209void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm, 210 struct ieee80211_key *key, 211 u8 *pos, size_t payload_len, u8 *ta) 212{ 213 u8 rc4key[16]; 214 215 ieee80211_tkip_gen_rc4key(key, ta, rc4key); 216 pos = ieee80211_tkip_add_iv(pos, key, rc4key[0], rc4key[1], rc4key[2]); 217 ieee80211_wep_encrypt_data(tfm, rc4key, 16, pos, payload_len); 218} 219 220/* Decrypt packet payload with TKIP using @key. @pos is a pointer to the 221 * beginning of the buffer containing IEEE 802.11 header payload, i.e., 222 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the 223 * length of payload, including IV, Ext. IV, MIC, ICV. */ 224int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm, 225 struct ieee80211_key *key, 226 u8 *payload, size_t payload_len, u8 *ta, 227 u8 *ra, int only_iv, int queue, 228 u32 *out_iv32, u16 *out_iv16) 229{ 230 u32 iv32; 231 u32 iv16; 232 u8 rc4key[16], keyid, *pos = payload; 233 int res; 234 235 if (payload_len < 12) 236 return -1; 237 238 iv16 = (pos[0] << 8) | pos[2]; 239 keyid = pos[3]; 240 iv32 = get_unaligned_le32(pos + 4); 241 pos += 8; 242#ifdef CONFIG_TKIP_DEBUG 243 { 244 int i; 245 printk(KERN_DEBUG "TKIP decrypt: data(len=%zd)", payload_len); 246 for (i = 0; i < payload_len; i++) 247 printk(" %02x", payload[i]); 248 printk("\n"); 249 printk(KERN_DEBUG "TKIP decrypt: iv16=%04x iv32=%08x\n", 250 iv16, iv32); 251 } 252#endif /* CONFIG_TKIP_DEBUG */ 253 254 if (!(keyid & (1 << 5))) 255 return TKIP_DECRYPT_NO_EXT_IV; 256 257 if ((keyid >> 6) != key->conf.keyidx) 258 return TKIP_DECRYPT_INVALID_KEYIDX; 259 260 if (key->u.tkip.rx[queue].initialized && 261 (iv32 < key->u.tkip.rx[queue].iv32 || 262 (iv32 == key->u.tkip.rx[queue].iv32 && 263 iv16 <= key->u.tkip.rx[queue].iv16))) { 264#ifdef CONFIG_TKIP_DEBUG 265 DECLARE_MAC_BUF(mac); 266 printk(KERN_DEBUG "TKIP replay detected for RX frame from " 267 "%s (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n", 268 print_mac(mac, ta), 269 iv32, iv16, key->u.tkip.rx[queue].iv32, 270 key->u.tkip.rx[queue].iv16); 271#endif /* CONFIG_TKIP_DEBUG */ 272 return TKIP_DECRYPT_REPLAY; 273 } 274 275 if (only_iv) { 276 res = TKIP_DECRYPT_OK; 277 key->u.tkip.rx[queue].initialized = 1; 278 goto done; 279 } 280 281 if (!key->u.tkip.rx[queue].initialized || 282 key->u.tkip.rx[queue].iv32 != iv32) { 283 /* IV16 wrapped around - perform TKIP phase 1 */ 284 tkip_mixing_phase1(key, ta, &key->u.tkip.rx[queue], iv32); 285#ifdef CONFIG_TKIP_DEBUG 286 { 287 int i; 288 DECLARE_MAC_BUF(mac); 289 printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%s" 290 " TK=", print_mac(mac, ta)); 291 for (i = 0; i < 16; i++) 292 printk("%02x ", 293 key->conf.key[ 294 ALG_TKIP_TEMP_ENCR_KEY + i]); 295 printk("\n"); 296 printk(KERN_DEBUG "TKIP decrypt: P1K="); 297 for (i = 0; i < 5; i++) 298 printk("%04x ", key->u.tkip.rx[queue].p1k[i]); 299 printk("\n"); 300 } 301#endif /* CONFIG_TKIP_DEBUG */ 302 if (key->local->ops->update_tkip_key && 303 key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) { 304 u8 bcast[ETH_ALEN] = 305 {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; 306 u8 *sta_addr = key->sta->addr; 307 308 if (is_multicast_ether_addr(ra)) 309 sta_addr = bcast; 310 311 key->local->ops->update_tkip_key( 312 local_to_hw(key->local), &key->conf, 313 sta_addr, iv32, key->u.tkip.rx[queue].p1k); 314 } 315 } 316 317 tkip_mixing_phase2(key, &key->u.tkip.rx[queue], iv16, rc4key); 318#ifdef CONFIG_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 /* CONFIG_TKIP_DEBUG */ 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