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alistair23-linux/net/mac80211/tkip.c
Johannes Berg 17741cdc26 mac80211: share STA information with driver 
This patch changes mac80211 to share some more data about
stations with drivers. Should help iwlwifi and ath9k when
 they get around to updating, and might also help with
implementing rate control algorithms without internals.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Sujith Manoharan <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-09-15 16:48:23 -04:00

344 lines
11 KiB
C
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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.
*/
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/netdevice.h>
#include <asm/unaligned.h>
#include <net/mac80211.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->initialized = 1;
}
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 *key, u16 iv16)
{
pos = write_tkip_iv(pos, iv16);
*pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */;
put_unaligned_le32(key->u.tkip.tx.iv32, pos);
return pos + 4;
}
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);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
u8 *data;
const u8 *tk;
struct tkip_ctx *ctx;
u16 iv16;
u32 iv32;
data = (u8 *)hdr + ieee80211_hdrlen(hdr->frame_control);
iv16 = data[2] | (data[0] << 8);
iv32 = get_unaligned_le32(&data[4]);
tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
ctx = &key->u.tkip.tx;
#ifdef CONFIG_MAC80211_TKIP_DEBUG
printk(KERN_DEBUG "TKIP encrypt: iv16 = 0x%04x, iv32 = 0x%08x\n",
iv16, iv32);
if (iv32 != ctx->iv32) {
printk(KERN_DEBUG "skb: iv32 = 0x%08x key: iv32 = 0x%08x\n",
iv32, ctx->iv32);
printk(KERN_DEBUG "Wrap around of iv16 in the middle of a "
"fragmented packet\n");
}
#endif
/* 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. */
if (iv16 == 0 || !ctx->initialized)
tkip_mixing_phase1(tk, ctx, hdr->addr2, iv32);
if (type == IEEE80211_TKIP_P1_KEY) {
memcpy(outkey, ctx->p1k, sizeof(u16) * 5);
return;
}
tkip_mixing_phase2(tk, ctx, iv16, outkey);
}
EXPORT_SYMBOL(ieee80211_get_tkip_key);
/* 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];
struct tkip_ctx *ctx = &key->u.tkip.tx;
const u8 *tk = &key->conf.key[NL80211_TKIP_DATA_OFFSET_ENCR_KEY];
/* 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);
pos = ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16);
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,
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];
if (payload_len < 12)
return -1;
iv16 = (pos[0] << 8) | pos[2];
keyid = pos[3];
iv32 = get_unaligned_le32(pos + 4);
pos += 8;
#ifdef CONFIG_MAC80211_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
if (!(keyid & (1 << 5)))
return TKIP_DECRYPT_NO_EXT_IV;
if ((keyid >> 6) != key->conf.keyidx)
return TKIP_DECRYPT_INVALID_KEYIDX;
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))) {
#ifdef CONFIG_MAC80211_TKIP_DEBUG
DECLARE_MAC_BUF(mac);
printk(KERN_DEBUG "TKIP replay detected for RX frame from "
"%s (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n",
print_mac(mac, ta),
iv32, iv16, key->u.tkip.rx[queue].iv32,
key->u.tkip.rx[queue].iv16);
#endif
return TKIP_DECRYPT_REPLAY;
}
if (only_iv) {
res = TKIP_DECRYPT_OK;
key->u.tkip.rx[queue].initialized = 1;
goto done;
}
if (!key->u.tkip.rx[queue].initialized ||
key->u.tkip.rx[queue].iv32 != iv32) {
/* IV16 wrapped around - perform TKIP phase 1 */
tkip_mixing_phase1(tk, &key->u.tkip.rx[queue], ta, iv32);
#ifdef CONFIG_MAC80211_TKIP_DEBUG
{
int i;
u8 key_offset = NL80211_TKIP_DATA_OFFSET_ENCR_KEY;
DECLARE_MAC_BUF(mac);
printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%s"
" TK=", print_mac(mac, ta));
for (i = 0; i < 16; i++)
printk("%02x ",
key->conf.key[key_offset + i]);
printk("\n");
printk(KERN_DEBUG "TKIP decrypt: P1K=");
for (i = 0; i < 5; i++)
printk("%04x ", key->u.tkip.rx[queue].p1k[i]);
printk("\n");
}
#endif
if (key->local->ops->update_tkip_key &&
key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
u8 bcast[ETH_ALEN] =
{0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
u8 *sta_addr = key->sta->sta.addr;
if (is_multicast_ether_addr(ra))
sta_addr = bcast;
key->local->ops->update_tkip_key(
local_to_hw(key->local), &key->conf,
sta_addr, iv32, key->u.tkip.rx[queue].p1k);
}
}
tkip_mixing_phase2(tk, &key->u.tkip.rx[queue], iv16, rc4key);
#ifdef CONFIG_MAC80211_TKIP_DEBUG
{
int i;
printk(KERN_DEBUG "TKIP decrypt: Phase2 rc4key=");
for (i = 0; i < 16; i++)
printk("%02x ", rc4key[i]);
printk("\n");
}
#endif
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;
}
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