/* * Copyright 2002-2004, Instant802 Networks, Inc. * Copyright 2005, Devicescape Software, Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/kernel.h> #include <linux/types.h> #include <linux/netdevice.h> #include <net/mac80211.h> #include "ieee80211_key.h" #include "tkip.h" #include "wep.h" /* TKIP key mixing functions */ #define PHASE1_LOOP_COUNT 8 /* 2-byte by 2-byte subset of the full AES S-box table; second part of this * table is identical to first part but byte-swapped */ static const u16 tkip_sbox[256] = { 0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154, 0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A, 0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B, 0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B, 0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F, 0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F, 0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5, 0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F, 0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB, 0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397, 0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED, 0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A, 0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194, 0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3, 0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104, 0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D, 0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39, 0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695, 0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83, 0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76, 0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4, 0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B, 0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0, 0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018, 0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751, 0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85, 0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12, 0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9, 0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7, 0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A, 0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8, 0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A, }; static inline u16 Mk16(u8 x, u8 y) { return ((u16) x << 8) | (u16) y; } static inline u8 Hi8(u16 v) { return v >> 8; } static inline u8 Lo8(u16 v) { return v & 0xff; } static inline u16 Hi16(u32 v) { return v >> 16; } static inline u16 Lo16(u32 v) { return v & 0xffff; } static inline u16 RotR1(u16 v) { return (v >> 1) | ((v & 0x0001) << 15); } static inline u16 tkip_S(u16 val) { u16 a = tkip_sbox[Hi8(val)]; return tkip_sbox[Lo8(val)] ^ Hi8(a) ^ (Lo8(a) << 8); } /* P1K := Phase1(TA, TK, TSC) * TA = transmitter address (48 bits) * TK = dot11DefaultKeyValue or dot11KeyMappingValue (128 bits) * TSC = TKIP sequence counter (48 bits, only 32 msb bits used) * P1K: 80 bits */ static void tkip_mixing_phase1(const u8 *ta, const u8 *tk, u32 tsc_IV32, u16 *p1k) { int i, j; p1k[0] = Lo16(tsc_IV32); p1k[1] = Hi16(tsc_IV32); p1k[2] = Mk16(ta[1], ta[0]); p1k[3] = Mk16(ta[3], ta[2]); p1k[4] = Mk16(ta[5], ta[4]); for (i = 0; i < PHASE1_LOOP_COUNT; i++) { j = 2 * (i & 1); p1k[0] += tkip_S(p1k[4] ^ Mk16(tk[ 1 + j], tk[ 0 + j])); p1k[1] += tkip_S(p1k[0] ^ Mk16(tk[ 5 + j], tk[ 4 + j])); p1k[2] += tkip_S(p1k[1] ^ Mk16(tk[ 9 + j], tk[ 8 + j])); p1k[3] += tkip_S(p1k[2] ^ Mk16(tk[13 + j], tk[12 + j])); p1k[4] += tkip_S(p1k[3] ^ Mk16(tk[ 1 + j], tk[ 0 + j])) + i; } } static void tkip_mixing_phase2(const u16 *p1k, const u8 *tk, u16 tsc_IV16, u8 *rc4key) { u16 ppk[6]; int i; ppk[0] = p1k[0]; ppk[1] = p1k[1]; ppk[2] = p1k[2]; ppk[3] = p1k[3]; ppk[4] = p1k[4]; ppk[5] = p1k[4] + tsc_IV16; ppk[0] += tkip_S(ppk[5] ^ Mk16(tk[ 1], tk[ 0])); ppk[1] += tkip_S(ppk[0] ^ Mk16(tk[ 3], tk[ 2])); ppk[2] += tkip_S(ppk[1] ^ Mk16(tk[ 5], tk[ 4])); ppk[3] += tkip_S(ppk[2] ^ Mk16(tk[ 7], tk[ 6])); ppk[4] += tkip_S(ppk[3] ^ Mk16(tk[ 9], tk[ 8])); ppk[5] += tkip_S(ppk[4] ^ Mk16(tk[11], tk[10])); ppk[0] += RotR1(ppk[5] ^ Mk16(tk[13], tk[12])); ppk[1] += RotR1(ppk[0] ^ Mk16(tk[15], tk[14])); ppk[2] += RotR1(ppk[1]); ppk[3] += RotR1(ppk[2]); ppk[4] += RotR1(ppk[3]); ppk[5] += RotR1(ppk[4]); rc4key[0] = Hi8(tsc_IV16); rc4key[1] = (Hi8(tsc_IV16) | 0x20) & 0x7f; rc4key[2] = Lo8(tsc_IV16); rc4key[3] = Lo8((ppk[5] ^ Mk16(tk[1], tk[0])) >> 1); for (i = 0; i < 6; i++) { rc4key[4 + 2 * i] = Lo8(ppk[i]); rc4key[5 + 2 * i] = Hi8(ppk[i]); } } /* Add TKIP IV and Ext. IV at @pos. @iv0, @iv1, and @iv2 are the first octets * of the IV. Returns pointer to the octet following IVs (i.e., beginning of * the packet payload). */ u8 * ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key, u8 iv0, u8 iv1, u8 iv2) { *pos++ = iv0; *pos++ = iv1; *pos++ = iv2; *pos++ = (key->keyidx << 6) | (1 << 5) /* Ext IV */; *pos++ = key->u.tkip.iv32 & 0xff; *pos++ = (key->u.tkip.iv32 >> 8) & 0xff; *pos++ = (key->u.tkip.iv32 >> 16) & 0xff; *pos++ = (key->u.tkip.iv32 >> 24) & 0xff; return pos; } void ieee80211_tkip_gen_phase1key(struct ieee80211_key *key, u8 *ta, u16 *phase1key) { tkip_mixing_phase1(ta, &key->key[ALG_TKIP_TEMP_ENCR_KEY], key->u.tkip.iv32, phase1key); } void ieee80211_tkip_gen_rc4key(struct ieee80211_key *key, u8 *ta, u8 *rc4key) { /* Calculate per-packet key */ if (key->u.tkip.iv16 == 0 || !key->u.tkip.tx_initialized) { /* IV16 wrapped around - perform TKIP phase 1 */ tkip_mixing_phase1(ta, &key->key[ALG_TKIP_TEMP_ENCR_KEY], key->u.tkip.iv32, key->u.tkip.p1k); key->u.tkip.tx_initialized = 1; } tkip_mixing_phase2(key->u.tkip.p1k, &key->key[ALG_TKIP_TEMP_ENCR_KEY], key->u.tkip.iv16, rc4key); } /* Encrypt packet payload with TKIP using @key. @pos is a pointer to the * beginning of the buffer containing payload. This payload must include * headroom of eight octets for IV and Ext. IV and taildroom of four octets * for ICV. @payload_len is the length of payload (_not_ including extra * headroom and tailroom). @ta is the transmitter addresses. */ void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm, struct ieee80211_key *key, u8 *pos, size_t payload_len, u8 *ta) { u8 rc4key[16]; ieee80211_tkip_gen_rc4key(key, ta, rc4key); pos = ieee80211_tkip_add_iv(pos, key, rc4key[0], rc4key[1], rc4key[2]); ieee80211_wep_encrypt_data(tfm, rc4key, 16, pos, payload_len); } /* Decrypt packet payload with TKIP using @key. @pos is a pointer to the * beginning of the buffer containing IEEE 802.11 header payload, i.e., * including IV, Ext. IV, real data, Michael MIC, ICV. @payload_len is the * length of payload, including IV, Ext. IV, MIC, ICV. */ int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm, struct ieee80211_key *key, u8 *payload, size_t payload_len, u8 *ta, int only_iv, int queue) { u32 iv32; u32 iv16; u8 rc4key[16], keyid, *pos = payload; int res; if (payload_len < 12) return -1; iv16 = (pos[0] << 8) | pos[2]; keyid = pos[3]; iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24); pos += 8; #ifdef CONFIG_TKIP_DEBUG { int i; printk(KERN_DEBUG "TKIP decrypt: data(len=%zd)", payload_len); for (i = 0; i < payload_len; i++) printk(" %02x", payload[i]); printk("\n"); printk(KERN_DEBUG "TKIP decrypt: iv16=%04x iv32=%08x\n", iv16, iv32); } #endif /* CONFIG_TKIP_DEBUG */ if (!(keyid & (1 << 5))) return TKIP_DECRYPT_NO_EXT_IV; if ((keyid >> 6) != key->keyidx) return TKIP_DECRYPT_INVALID_KEYIDX; if (key->u.tkip.rx_initialized[queue] && (iv32 < key->u.tkip.iv32_rx[queue] || (iv32 == key->u.tkip.iv32_rx[queue] && iv16 <= key->u.tkip.iv16_rx[queue]))) { #ifdef CONFIG_TKIP_DEBUG printk(KERN_DEBUG "TKIP replay detected for RX frame from " MAC_FMT " (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n", MAC_ARG(ta), iv32, iv16, key->u.tkip.iv32_rx[queue], key->u.tkip.iv16_rx[queue]); #endif /* CONFIG_TKIP_DEBUG */ return TKIP_DECRYPT_REPLAY; } if (only_iv) { res = TKIP_DECRYPT_OK; key->u.tkip.rx_initialized[queue] = 1; goto done; } if (!key->u.tkip.rx_initialized[queue] || key->u.tkip.iv32_rx[queue] != iv32) { key->u.tkip.rx_initialized[queue] = 1; /* IV16 wrapped around - perform TKIP phase 1 */ tkip_mixing_phase1(ta, &key->key[ALG_TKIP_TEMP_ENCR_KEY], iv32, key->u.tkip.p1k_rx[queue]); #ifdef CONFIG_TKIP_DEBUG { int i; printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=" MAC_FMT " TK=", MAC_ARG(ta)); for (i = 0; i < 16; i++) printk("%02x ", key->key[ALG_TKIP_TEMP_ENCR_KEY + i]); printk("\n"); printk(KERN_DEBUG "TKIP decrypt: P1K="); for (i = 0; i < 5; i++) printk("%04x ", key->u.tkip.p1k_rx[queue][i]); printk("\n"); } #endif /* CONFIG_TKIP_DEBUG */ } tkip_mixing_phase2(key->u.tkip.p1k_rx[queue], &key->key[ALG_TKIP_TEMP_ENCR_KEY], iv16, rc4key); #ifdef CONFIG_TKIP_DEBUG { int i; printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key="); for (i = 0; i < 16; i++) printk("%02x ", rc4key[i]); printk("\n"); } #endif /* CONFIG_TKIP_DEBUG */ res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12); done: if (res == TKIP_DECRYPT_OK) { /* FIX: these should be updated only after Michael MIC has been * verified */ /* Record previously received IV */ key->u.tkip.iv32_rx[queue] = iv32; key->u.tkip.iv16_rx[queue] = iv16; } return res; }