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linux-next/net/mac80211/tkip.c
John W. Linville 3473187d24 mac80211: remove wep dependency 
The current mac80211 code assumes that WEP is always available.  If WEP
fails to initialize, ieee80211_register_hw will always fail.

In some cases (e.g. FIPS certification), the cryptography used by WEP is
unavailable.  However, in such cases there is no good reason why CCMP
encryption (or even no link level encryption) cannot be used.  So, this
patch removes mac80211's assumption that WEP (and TKIP) will always be
available for use.

Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-07-08 16:35:50 -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;
}
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->state == TKIP_STATE_NOT_INIT)
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
* 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_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->state == TKIP_STATE_NOT_INIT)
tkip_mixing_phase1(tk, ctx, ta, ctx->iv32);
tkip_mixing_phase2(tk, ctx, ctx->iv16, rc4key);
return 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].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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