diff options
Diffstat (limited to 'net/mac80211/tkip.c')
| -rw-r--r-- | net/mac80211/tkip.c | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/net/mac80211/tkip.c b/net/mac80211/tkip.c new file mode 100644 index 000000000..ebd66e8f4 --- /dev/null +++ b/net/mac80211/tkip.c @@ -0,0 +1,326 @@ +/* + * Copyright 2002-2004, Instant802 Networks, Inc. + * Copyright 2005, Devicescape Software, Inc. + * Copyright (C) 2016 Intel Deutschland GmbH + * + * 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/bitops.h> +#include <linux/types.h> +#include <linux/netdevice.h> +#include <linux/export.h> +#include <asm/unaligned.h> + +#include <net/mac80211.h> +#include "driver-ops.h" +#include "key.h" +#include "tkip.h" +#include "wep.h" + +#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 u16 tkipS(u16 val) +{ + return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]); +} + +static u8 *write_tkip_iv(u8 *pos, u16 iv16) +{ + *pos++ = iv16 >> 8; + *pos++ = ((iv16 >> 8) | 0x20) & 0x7f; + *pos++ = iv16 & 0xFF; + return pos; +} + +/* + * 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 *tk, struct tkip_ctx *ctx, + const u8 *ta, u32 tsc_IV32) +{ + int i, j; + u16 *p1k = ctx->p1k; + + 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); + + for (i = 0; i < PHASE1_LOOP_COUNT; i++) { + j = 2 * (i & 1); + 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; + } + ctx->state = TKIP_STATE_PHASE1_DONE; + ctx->p1k_iv32 = tsc_IV32; +} + +static void tkip_mixing_phase2(const u8 *tk, struct tkip_ctx *ctx, + u16 tsc_IV16, u8 *rc4key) +{ + u16 ppk[6]; + const u16 *p1k = ctx->p1k; + 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] += 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); + + rc4key = write_tkip_iv(rc4key, tsc_IV16); + *rc4key++ = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF; + + for (i = 0; i < 6; i++) + put_unaligned_le16(ppk[i], rc4key + 2 * 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_conf *keyconf, u64 pn) +{ + pos = write_tkip_iv(pos, TKIP_PN_TO_IV16(pn)); + *pos++ = (keyconf->keyidx << 6) | (1 << 5) /* Ext IV */; + put_unaligned_le32(TKIP_PN_TO_IV32(pn), pos); + return pos + 4; +} +EXPORT_SYMBOL_GPL(ieee80211_tkip_add_iv); + +static void ieee80211_compute_tkip_p1k(struct ieee80211_key *key, u32 iv32) +{ + struct ieee80211_sub_if_data *sdata = key->sdata; + struct tkip_ctx *ctx = &key->u.tkip.tx; + const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; + + lockdep_assert_held(&key->u.tkip.txlock); + + /* + * Update the P1K when the IV32 is different from the value it + * had when we last computed it (or when not initialised yet). + * This might flip-flop back and forth if packets are processed + * out-of-order due to the different ACs, but then we have to + * just compute the P1K more often. + */ + if (ctx->p1k_iv32 != iv32 || ctx->state == TKIP_STATE_NOT_INIT) + tkip_mixing_phase1(tk, ctx, sdata->vif.addr, iv32); +} + +void ieee80211_get_tkip_p1k_iv(struct ieee80211_key_conf *keyconf, + u32 iv32, u16 *p1k) +{ + struct ieee80211_key *key = (struct ieee80211_key *) + container_of(keyconf, struct ieee80211_key, conf); + struct tkip_ctx *ctx = &key->u.tkip.tx; + + spin_lock_bh(&key->u.tkip.txlock); + ieee80211_compute_tkip_p1k(key, iv32); + memcpy(p1k, ctx->p1k, sizeof(ctx->p1k)); + spin_unlock_bh(&key->u.tkip.txlock); +} +EXPORT_SYMBOL(ieee80211_get_tkip_p1k_iv); + +void ieee80211_get_tkip_rx_p1k(struct ieee80211_key_conf *keyconf, + const u8 *ta, u32 iv32, u16 *p1k) +{ + const u8 *tk = &keyconf->key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; + struct tkip_ctx ctx; + + tkip_mixing_phase1(tk, &ctx, ta, iv32); + memcpy(p1k, ctx.p1k, sizeof(ctx.p1k)); +} +EXPORT_SYMBOL(ieee80211_get_tkip_rx_p1k); + +void ieee80211_get_tkip_p2k(struct ieee80211_key_conf *keyconf, + struct sk_buff *skb, u8 *p2k) +{ + struct ieee80211_key *key = (struct ieee80211_key *) + container_of(keyconf, struct ieee80211_key, conf); + const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; + struct tkip_ctx *ctx = &key->u.tkip.tx; + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; + const u8 *data = (u8 *)hdr + ieee80211_hdrlen(hdr->frame_control); + u32 iv32 = get_unaligned_le32(&data[4]); + u16 iv16 = data[2] | (data[0] << 8); + + spin_lock(&key->u.tkip.txlock); + ieee80211_compute_tkip_p1k(key, iv32); + tkip_mixing_phase2(tk, ctx, iv16, p2k); + spin_unlock(&key->u.tkip.txlock); +} +EXPORT_SYMBOL(ieee80211_get_tkip_p2k); + +/* + * Encrypt packet payload with TKIP using @key. @pos is a pointer to the + * beginning of the buffer containing payload. This payload must include + * the IV/Ext.IV and space for (taildroom) four octets for ICV. + * @payload_len is the length of payload (_not_ including IV/ICV length). + * @ta is the transmitter addresses. + */ +int ieee80211_tkip_encrypt_data(struct crypto_cipher *tfm, + struct ieee80211_key *key, + struct sk_buff *skb, + u8 *payload, size_t payload_len) +{ + u8 rc4key[16]; + + ieee80211_get_tkip_p2k(&key->conf, skb, rc4key); + + return ieee80211_wep_encrypt_data(tfm, rc4key, 16, + payload, 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_cipher *tfm, + struct ieee80211_key *key, + u8 *payload, size_t payload_len, u8 *ta, + u8 *ra, int only_iv, int queue, + u32 *out_iv32, u16 *out_iv16) +{ + u32 iv32; + u32 iv16; + u8 rc4key[16], keyid, *pos = payload; + int res; + const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY]; + struct tkip_ctx_rx *rx_ctx = &key->u.tkip.rx[queue]; + + if (payload_len < 12) + return -1; + + iv16 = (pos[0] << 8) | pos[2]; + keyid = pos[3]; + iv32 = get_unaligned_le32(pos + 4); + pos += 8; + + if (!(keyid & (1 << 5))) + return TKIP_DECRYPT_NO_EXT_IV; + + if ((keyid >> 6) != key->conf.keyidx) + return TKIP_DECRYPT_INVALID_KEYIDX; + + /* Reject replays if the received TSC is smaller than or equal to the + * last received value in a valid message, but with an exception for + * the case where a new key has been set and no valid frame using that + * key has yet received and the local RSC was initialized to 0. This + * exception allows the very first frame sent by the transmitter to be + * accepted even if that transmitter were to use TSC 0 (IEEE 802.11 + * described TSC to be initialized to 1 whenever a new key is taken into + * use). + */ + if (iv32 < rx_ctx->iv32 || + (iv32 == rx_ctx->iv32 && + (iv16 < rx_ctx->iv16 || + (iv16 == rx_ctx->iv16 && + (rx_ctx->iv32 || rx_ctx->iv16 || + rx_ctx->ctx.state != TKIP_STATE_NOT_INIT))))) + return TKIP_DECRYPT_REPLAY; + + if (only_iv) { + res = TKIP_DECRYPT_OK; + rx_ctx->ctx.state = TKIP_STATE_PHASE1_HW_UPLOADED; + goto done; + } + + if (rx_ctx->ctx.state == TKIP_STATE_NOT_INIT || + rx_ctx->iv32 != iv32) { + /* IV16 wrapped around - perform TKIP phase 1 */ + tkip_mixing_phase1(tk, &rx_ctx->ctx, ta, iv32); + } + if (key->local->ops->update_tkip_key && + key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE && + rx_ctx->ctx.state != TKIP_STATE_PHASE1_HW_UPLOADED) { + struct ieee80211_sub_if_data *sdata = key->sdata; + + if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) + sdata = container_of(key->sdata->bss, + struct ieee80211_sub_if_data, u.ap); + drv_update_tkip_key(key->local, sdata, &key->conf, key->sta, + iv32, rx_ctx->ctx.p1k); + rx_ctx->ctx.state = TKIP_STATE_PHASE1_HW_UPLOADED; + } + + tkip_mixing_phase2(tk, &rx_ctx->ctx, iv16, rc4key); + + res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12); + done: + if (res == TKIP_DECRYPT_OK) { + /* + * 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; + } + + return res; +} |