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net/mac80211/tkip.c
10.9 KB
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/* * 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. */ |
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#include <linux/kernel.h> |
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#include <linux/bitops.h> |
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#include <linux/types.h> #include <linux/netdevice.h> |
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#include <asm/unaligned.h> |
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#include <net/mac80211.h> |
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#include "driver-ops.h" |
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#include "key.h" |
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#include "tkip.h" #include "wep.h" |
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#define PHASE1_LOOP_COUNT 8 |
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/* * 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 */ |
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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, }; |
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static u16 tkipS(u16 val) |
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{ |
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return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]); |
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} |
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static u8 *write_tkip_iv(u8 *pos, u16 iv16) { *pos++ = iv16 >> 8; *pos++ = ((iv16 >> 8) | 0x20) & 0x7f; *pos++ = iv16 & 0xFF; return pos; } |
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/* * P1K := Phase1(TA, TK, TSC) |
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* 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 */ |
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static void tkip_mixing_phase1(const u8 *tk, struct tkip_ctx *ctx, const u8 *ta, u32 tsc_IV32) |
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{ int i, j; |
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u16 *p1k = ctx->p1k; |
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p1k[0] = tsc_IV32 & 0xFFFF; p1k[1] = tsc_IV32 >> 16; p1k[2] = get_unaligned_le16(ta + 0); p1k[3] = get_unaligned_le16(ta + 2); p1k[4] = get_unaligned_le16(ta + 4); |
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for (i = 0; i < PHASE1_LOOP_COUNT; i++) { j = 2 * (i & 1); |
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p1k[0] += tkipS(p1k[4] ^ get_unaligned_le16(tk + 0 + j)); p1k[1] += tkipS(p1k[0] ^ get_unaligned_le16(tk + 4 + j)); p1k[2] += tkipS(p1k[1] ^ get_unaligned_le16(tk + 8 + j)); p1k[3] += tkipS(p1k[2] ^ get_unaligned_le16(tk + 12 + j)); p1k[4] += tkipS(p1k[3] ^ get_unaligned_le16(tk + 0 + j)) + i; |
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} |
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ctx->initialized = 1; |
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} |
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static void tkip_mixing_phase2(const u8 *tk, struct tkip_ctx *ctx, |
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u16 tsc_IV16, u8 *rc4key) |
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{ u16 ppk[6]; |
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const u16 *p1k = ctx->p1k; |
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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; |
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ppk[0] += tkipS(ppk[5] ^ get_unaligned_le16(tk + 0)); ppk[1] += tkipS(ppk[0] ^ get_unaligned_le16(tk + 2)); ppk[2] += tkipS(ppk[1] ^ get_unaligned_le16(tk + 4)); ppk[3] += tkipS(ppk[2] ^ get_unaligned_le16(tk + 6)); ppk[4] += tkipS(ppk[3] ^ get_unaligned_le16(tk + 8)); ppk[5] += tkipS(ppk[4] ^ get_unaligned_le16(tk + 10)); ppk[0] += ror16(ppk[5] ^ get_unaligned_le16(tk + 12), 1); ppk[1] += ror16(ppk[0] ^ get_unaligned_le16(tk + 14), 1); ppk[2] += ror16(ppk[1], 1); ppk[3] += ror16(ppk[2], 1); ppk[4] += ror16(ppk[3], 1); ppk[5] += ror16(ppk[4], 1); |
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rc4key = write_tkip_iv(rc4key, tsc_IV16); *rc4key++ = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF; |
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for (i = 0; i < 6; i++) put_unaligned_le16(ppk[i], rc4key + 2 * i); |
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} |
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/* 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). */ |
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u8 *ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key, u16 iv16) |
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{ |
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pos = write_tkip_iv(pos, iv16); |
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*pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */; |
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put_unaligned_le32(key->u.tkip.tx.iv32, pos); |
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return pos + 4; |
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} |
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void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf, struct sk_buff *skb, enum ieee80211_tkip_key_type type, u8 *outkey) { struct ieee80211_key *key = (struct ieee80211_key *) container_of(keyconf, struct ieee80211_key, conf); |
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; u8 *data; const u8 *tk; struct tkip_ctx *ctx; |
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u16 iv16; u32 iv32; |
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data = (u8 *)hdr + ieee80211_hdrlen(hdr->frame_control); iv16 = data[2] | (data[0] << 8); iv32 = get_unaligned_le32(&data[4]); |
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tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; |
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ctx = &key->u.tkip.tx; |
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#ifdef CONFIG_MAC80211_TKIP_DEBUG |
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printk(KERN_DEBUG "TKIP encrypt: iv16 = 0x%04x, iv32 = 0x%08x ", iv16, iv32); |
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if (iv32 != ctx->iv32) { |
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printk(KERN_DEBUG "skb: iv32 = 0x%08x key: iv32 = 0x%08x ", |
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iv32, ctx->iv32); |
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printk(KERN_DEBUG "Wrap around of iv16 in the middle of a " "fragmented packet "); } |
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#endif |
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/* Update the p1k only when the iv16 in the packet wraps around, this * might occur after the wrap around of iv16 in the key in case of * fragmented packets. */ |
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if (iv16 == 0 || !ctx->initialized) tkip_mixing_phase1(tk, ctx, hdr->addr2, iv32); |
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if (type == IEEE80211_TKIP_P1_KEY) { |
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memcpy(outkey, ctx->p1k, sizeof(u16) * 5); |
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return; } |
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tkip_mixing_phase2(tk, ctx, iv16, outkey); |
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} EXPORT_SYMBOL(ieee80211_get_tkip_key); |
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/* 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]; |
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struct tkip_ctx *ctx = &key->u.tkip.tx; |
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const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; |
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/* Calculate per-packet key */ if (ctx->iv16 == 0 || !ctx->initialized) tkip_mixing_phase1(tk, ctx, ta, ctx->iv32); tkip_mixing_phase2(tk, ctx, ctx->iv16, rc4key); |
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pos = ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16); |
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ieee80211_wep_encrypt_data(tfm, rc4key, 16, pos, payload_len); } |
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/* 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, |
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u8 *ra, int only_iv, int queue, |
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u32 *out_iv32, u16 *out_iv16) |
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{ u32 iv32; u32 iv16; u8 rc4key[16], keyid, *pos = payload; int res; |
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const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; |
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if (payload_len < 12) return -1; iv16 = (pos[0] << 8) | pos[2]; keyid = pos[3]; |
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iv32 = get_unaligned_le32(pos + 4); |
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pos += 8; |
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#ifdef CONFIG_MAC80211_TKIP_DEBUG |
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{ int i; printk(KERN_DEBUG "TKIP decrypt: data(len=%zd)", payload_len); for (i = 0; i < payload_len; i++) printk(" %02x", payload[i]); printk(" "); printk(KERN_DEBUG "TKIP decrypt: iv16=%04x iv32=%08x ", iv16, iv32); } |
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#endif |
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if (!(keyid & (1 << 5))) return TKIP_DECRYPT_NO_EXT_IV; |
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if ((keyid >> 6) != key->conf.keyidx) |
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return TKIP_DECRYPT_INVALID_KEYIDX; |
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if (key->u.tkip.rx[queue].initialized && (iv32 < key->u.tkip.rx[queue].iv32 || (iv32 == key->u.tkip.rx[queue].iv32 && iv16 <= key->u.tkip.rx[queue].iv16))) { |
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#ifdef CONFIG_MAC80211_TKIP_DEBUG |
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printk(KERN_DEBUG "TKIP replay detected for RX frame from " |
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"%pM (RX IV (%04x,%02x) <= prev. IV (%04x,%02x) ", ta, |
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iv32, iv16, key->u.tkip.rx[queue].iv32, key->u.tkip.rx[queue].iv16); |
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#endif |
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return TKIP_DECRYPT_REPLAY; } if (only_iv) { res = TKIP_DECRYPT_OK; |
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key->u.tkip.rx[queue].initialized = 1; |
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goto done; } |
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if (!key->u.tkip.rx[queue].initialized || key->u.tkip.rx[queue].iv32 != iv32) { |
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/* IV16 wrapped around - perform TKIP phase 1 */ |
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tkip_mixing_phase1(tk, &key->u.tkip.rx[queue], ta, iv32); |
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#ifdef CONFIG_MAC80211_TKIP_DEBUG |
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{ int i; |
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u8 key_offset = NL80211_TKIP_DATA_OFFSET_ENCR_KEY; |
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printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%pM" " TK=", ta); |
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for (i = 0; i < 16; i++) printk("%02x ", |
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key->conf.key[key_offset + i]); |
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printk(" "); printk(KERN_DEBUG "TKIP decrypt: P1K="); for (i = 0; i < 5; i++) |
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printk("%04x ", key->u.tkip.rx[queue].p1k[i]); |
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printk(" "); } |
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#endif |
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if (key->local->ops->update_tkip_key && key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) { u8 bcast[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; |
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u8 *sta_addr = key->sta->sta.addr; |
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if (is_multicast_ether_addr(ra)) sta_addr = bcast; |
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drv_update_tkip_key(key->local, &key->conf, sta_addr, iv32, key->u.tkip.rx[queue].p1k); |
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} |
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} |
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tkip_mixing_phase2(tk, &key->u.tkip.rx[queue], iv16, rc4key); |
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#ifdef CONFIG_MAC80211_TKIP_DEBUG |
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{ int i; printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key="); for (i = 0; i < 16; i++) printk("%02x ", rc4key[i]); printk(" "); } |
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#endif |
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res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12); done: if (res == TKIP_DECRYPT_OK) { |
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/* * Record previously received IV, will be copied into the * key information after MIC verification. It is possible * that we don't catch replays of fragments but that's ok * because the Michael MIC verication will then fail. */ *out_iv32 = iv32; *out_iv16 = iv16; |
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} return res; } |