tkip.c revision c801242c38de247d82f12f6bf28bd19a280a12ae
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 67static u8 *write_tkip_iv(u8 *pos, u16 iv16) 68{ 69 *pos++ = iv16 >> 8; 70 *pos++ = ((iv16 >> 8) | 0x20) & 0x7f; 71 *pos++ = iv16 & 0xFF; 72 return pos; 73} 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 */ 83static void tkip_mixing_phase1(struct ieee80211_key *key, const u8 *ta, 84 struct tkip_ctx *ctx, u32 tsc_IV32) 85{ 86 int i, j; 87 const u8 *tk = &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY]; 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->initialized = 1; 105} 106 107static void tkip_mixing_phase2(struct ieee80211_key *key, struct tkip_ctx *ctx, 108 u16 tsc_IV16, u8 *rc4key) 109{ 110 u16 ppk[6]; 111 const u16 *p1k = ctx->p1k; 112 const u8 *tk = &key->conf.key[ALG_TKIP_TEMP_ENCR_KEY]; 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). */ 145u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key, u16 iv16) 146{ 147 pos = write_tkip_iv(pos, iv16); 148 *pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */; 149 put_unaligned_le32(key->u.tkip.tx.iv32, pos); 150 return pos + 4; 151} 152 153static void ieee80211_tkip_gen_rc4key(struct ieee80211_key *key, u8 *ta, 154 u8 *rc4key) 155{ 156 /* Calculate per-packet key */ 157 if (key->u.tkip.tx.iv16 == 0 || !key->u.tkip.tx.initialized) 158 tkip_mixing_phase1(key, ta, &key->u.tkip.tx, key->u.tkip.tx.iv32); 159 160 tkip_mixing_phase2(key, &key->u.tkip.tx, key->u.tkip.tx.iv16, rc4key); 161} 162 163void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf, 164 struct sk_buff *skb, enum ieee80211_tkip_key_type type, 165 u8 *outkey) 166{ 167 struct ieee80211_key *key = (struct ieee80211_key *) 168 container_of(keyconf, struct ieee80211_key, conf); 169 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 170 u8 *data = (u8 *) hdr; 171 u16 fc = le16_to_cpu(hdr->frame_control); 172 int hdr_len = ieee80211_get_hdrlen(fc); 173 u8 *ta = hdr->addr2; 174 u16 iv16; 175 u32 iv32; 176 177 iv16 = data[hdr_len + 2] | (data[hdr_len] << 8); 178 iv32 = get_unaligned_le32(data + hdr_len + 4); 179 180#ifdef CONFIG_TKIP_DEBUG 181 printk(KERN_DEBUG "TKIP encrypt: iv16 = 0x%04x, iv32 = 0x%08x\n", 182 iv16, iv32); 183 184 if (iv32 != key->u.tkip.tx.iv32) { 185 printk(KERN_DEBUG "skb: iv32 = 0x%08x key: iv32 = 0x%08x\n", 186 iv32, key->u.tkip.tx.iv32); 187 printk(KERN_DEBUG "Wrap around of iv16 in the middle of a " 188 "fragmented packet\n"); 189 } 190#endif /* CONFIG_TKIP_DEBUG */ 191 192 /* Update the p1k only when the iv16 in the packet wraps around, this 193 * might occur after the wrap around of iv16 in the key in case of 194 * fragmented packets. */ 195 if (iv16 == 0 || !key->u.tkip.tx.initialized) 196 tkip_mixing_phase1(key, ta, &key->u.tkip.tx, iv32); 197 198 if (type == IEEE80211_TKIP_P1_KEY) { 199 memcpy(outkey, key->u.tkip.tx.p1k, sizeof(u16) * 5); 200 return; 201 } 202 203 tkip_mixing_phase2(key, &key->u.tkip.tx, iv16, outkey); 204} 205EXPORT_SYMBOL(ieee80211_get_tkip_key); 206 207/* Encrypt packet payload with TKIP using @key. @pos is a pointer to the 208 * beginning of the buffer containing payload. This payload must include 209 * headroom of eight octets for IV and Ext. IV and taildroom of four octets 210 * for ICV. @payload_len is the length of payload (_not_ including extra 211 * headroom and tailroom). @ta is the transmitter addresses. */ 212void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm, 213 struct ieee80211_key *key, 214 u8 *pos, size_t payload_len, u8 *ta) 215{ 216 u8 rc4key[16]; 217 218 ieee80211_tkip_gen_rc4key(key, ta, rc4key); 219 pos = ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16); 220 ieee80211_wep_encrypt_data(tfm, rc4key, 16, pos, payload_len); 221} 222 223/* Decrypt packet payload with TKIP using @key. @pos is a pointer to the 224 * beginning of the buffer containing IEEE 802.11 header payload, i.e., 225 * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the 226 * length of payload, including IV, Ext. IV, MIC, ICV. */ 227int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm, 228 struct ieee80211_key *key, 229 u8 *payload, size_t payload_len, u8 *ta, 230 u8 *ra, int only_iv, int queue, 231 u32 *out_iv32, u16 *out_iv16) 232{ 233 u32 iv32; 234 u32 iv16; 235 u8 rc4key[16], keyid, *pos = payload; 236 int res; 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_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 /* CONFIG_TKIP_DEBUG */ 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].initialized && 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_TKIP_DEBUG 268 DECLARE_MAC_BUF(mac); 269 printk(KERN_DEBUG "TKIP replay detected for RX frame from " 270 "%s (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n", 271 print_mac(mac, ta), 272 iv32, iv16, key->u.tkip.rx[queue].iv32, 273 key->u.tkip.rx[queue].iv16); 274#endif /* CONFIG_TKIP_DEBUG */ 275 return TKIP_DECRYPT_REPLAY; 276 } 277 278 if (only_iv) { 279 res = TKIP_DECRYPT_OK; 280 key->u.tkip.rx[queue].initialized = 1; 281 goto done; 282 } 283 284 if (!key->u.tkip.rx[queue].initialized || 285 key->u.tkip.rx[queue].iv32 != iv32) { 286 /* IV16 wrapped around - perform TKIP phase 1 */ 287 tkip_mixing_phase1(key, ta, &key->u.tkip.rx[queue], iv32); 288#ifdef CONFIG_TKIP_DEBUG 289 { 290 int i; 291 DECLARE_MAC_BUF(mac); 292 printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%s" 293 " TK=", print_mac(mac, ta)); 294 for (i = 0; i < 16; i++) 295 printk("%02x ", 296 key->conf.key[ 297 ALG_TKIP_TEMP_ENCR_KEY + i]); 298 printk("\n"); 299 printk(KERN_DEBUG "TKIP decrypt: P1K="); 300 for (i = 0; i < 5; i++) 301 printk("%04x ", key->u.tkip.rx[queue].p1k[i]); 302 printk("\n"); 303 } 304#endif /* CONFIG_TKIP_DEBUG */ 305 if (key->local->ops->update_tkip_key && 306 key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) { 307 u8 bcast[ETH_ALEN] = 308 {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; 309 u8 *sta_addr = key->sta->addr; 310 311 if (is_multicast_ether_addr(ra)) 312 sta_addr = bcast; 313 314 key->local->ops->update_tkip_key( 315 local_to_hw(key->local), &key->conf, 316 sta_addr, iv32, key->u.tkip.rx[queue].p1k); 317 } 318 } 319 320 tkip_mixing_phase2(key, &key->u.tkip.rx[queue], iv16, rc4key); 321#ifdef CONFIG_TKIP_DEBUG 322 { 323 int i; 324 printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key="); 325 for (i = 0; i < 16; i++) 326 printk("%02x ", rc4key[i]); 327 printk("\n"); 328 } 329#endif /* CONFIG_TKIP_DEBUG */ 330 331 res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12); 332 done: 333 if (res == TKIP_DECRYPT_OK) { 334 /* 335 * Record previously received IV, will be copied into the 336 * key information after MIC verification. It is possible 337 * that we don't catch replays of fragments but that's ok 338 * because the Michael MIC verication will then fail. 339 */ 340 *out_iv32 = iv32; 341 *out_iv16 = iv16; 342 } 343 344 return res; 345} 346