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linux-next/net/mac80211/tkip.c
Johannes Berg 42d9879550 mac80211: allow driver to generate P1K for IV32 
In order to support pre-populating the P1K cache in
iwlwifi hardware for WoWLAN, we need to calculate
the P1K for the current IV32. Allow drivers to get
the P1K for any given IV32 instead of for a given
packet, but keep the packet-based version around as
an inline.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-07-08 11:42:23 -04:00

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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 "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 *key)
{
lockdep_assert_held(&key->u.tkip.txlock);
pos = write_tkip_iv(pos, key->u.tkip.tx.iv16);
*pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */;
put_unaligned_le32(key->u.tkip.tx.iv32, pos);
return pos + 4;
}
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;
unsigned long flags;
spin_lock_irqsave(&key->u.tkip.txlock, flags);
ieee80211_compute_tkip_p1k(key, iv32);
memcpy(p1k, ctx->p1k, sizeof(ctx->p1k));
spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
}
EXPORT_SYMBOL(ieee80211_get_tkip_p1k_iv);
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);
unsigned long flags;
spin_lock_irqsave(&key->u.tkip.txlock, flags);
ieee80211_compute_tkip_p1k(key, iv32);
tkip_mixing_phase2(tk, ctx, iv16, p2k);
spin_unlock_irqrestore(&key->u.tkip.txlock, flags);
}
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];
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].state != TKIP_STATE_NOT_INIT &&
(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
printk(KERN_DEBUG "TKIP replay detected for RX frame from "
"%pM (RX IV (%04x,%02x) <= prev. IV (%04x,%02x)\n",
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].state = TKIP_STATE_PHASE1_HW_UPLOADED;
goto done;
}
if (key->u.tkip.rx[queue].state == TKIP_STATE_NOT_INIT ||
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;
printk(KERN_DEBUG "TKIP decrypt: Phase1 TA=%pM"
" TK=", 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 &&
key->u.tkip.rx[queue].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, key->u.tkip.rx[queue].p1k);
key->u.tkip.rx[queue].state = TKIP_STATE_PHASE1_HW_UPLOADED;
}
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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