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mac80211: tkip.c use kernel-provided infrastructure
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Use kernel-provided bit rotation and unaligned access infrastructure rather
than opencoding it.

Some minor spacing adjustments as well.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Harvey Harrison authored and John W. Linville committed May 14, 2008
1 parent ae7245c commit 8c046c8
Showing 1 changed file with 46 additions and 99 deletions.
145 changes: 46 additions & 99 deletions net/mac80211/tkip.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,23 +8,22 @@
*/

#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"


/* TKIP key mixing functions */


#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 */
/*
* 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,
Expand Down Expand Up @@ -61,53 +60,13 @@ static const u16 tkip_sbox[256] =
0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
};


static inline u16 Mk16(u8 x, u8 y)
{
return ((u16) x << 8) | (u16) y;
}


static inline u8 Hi8(u16 v)
{
return v >> 8;
}


static inline u8 Lo8(u16 v)
{
return v & 0xff;
}


static inline u16 Hi16(u32 v)
{
return v >> 16;
}


static inline u16 Lo16(u32 v)
{
return v & 0xffff;
}


static inline u16 RotR1(u16 v)
static u16 tkipS(u16 val)
{
return (v >> 1) | ((v & 0x0001) << 15);
}


static inline u16 tkip_S(u16 val)
{
u16 a = tkip_sbox[Hi8(val)];

return tkip_sbox[Lo8(val)] ^ Hi8(a) ^ (Lo8(a) << 8);
return tkip_sbox[val & 0xff] ^ swab16(tkip_sbox[val >> 8]);
}



/* P1K := Phase1(TA, TK, TSC)
/*
* 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)
Expand All @@ -118,23 +77,22 @@ static void tkip_mixing_phase1(const u8 *ta, const u8 *tk, u32 tsc_IV32,
{
int i, j;

p1k[0] = Lo16(tsc_IV32);
p1k[1] = Hi16(tsc_IV32);
p1k[2] = Mk16(ta[1], ta[0]);
p1k[3] = Mk16(ta[3], ta[2]);
p1k[4] = Mk16(ta[5], ta[4]);
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] += tkip_S(p1k[4] ^ Mk16(tk[ 1 + j], tk[ 0 + j]));
p1k[1] += tkip_S(p1k[0] ^ Mk16(tk[ 5 + j], tk[ 4 + j]));
p1k[2] += tkip_S(p1k[1] ^ Mk16(tk[ 9 + j], tk[ 8 + j]));
p1k[3] += tkip_S(p1k[2] ^ Mk16(tk[13 + j], tk[12 + j]));
p1k[4] += tkip_S(p1k[3] ^ Mk16(tk[ 1 + j], tk[ 0 + j])) + i;
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;
}
}


static void tkip_mixing_phase2(const u16 *p1k, const u8 *tk, u16 tsc_IV16,
u8 *rc4key)
{
Expand All @@ -148,31 +106,29 @@ static void tkip_mixing_phase2(const u16 *p1k, const u8 *tk, u16 tsc_IV16,
ppk[4] = p1k[4];
ppk[5] = p1k[4] + tsc_IV16;

ppk[0] += tkip_S(ppk[5] ^ Mk16(tk[ 1], tk[ 0]));
ppk[1] += tkip_S(ppk[0] ^ Mk16(tk[ 3], tk[ 2]));
ppk[2] += tkip_S(ppk[1] ^ Mk16(tk[ 5], tk[ 4]));
ppk[3] += tkip_S(ppk[2] ^ Mk16(tk[ 7], tk[ 6]));
ppk[4] += tkip_S(ppk[3] ^ Mk16(tk[ 9], tk[ 8]));
ppk[5] += tkip_S(ppk[4] ^ Mk16(tk[11], tk[10]));
ppk[0] += RotR1(ppk[5] ^ Mk16(tk[13], tk[12]));
ppk[1] += RotR1(ppk[0] ^ Mk16(tk[15], tk[14]));
ppk[2] += RotR1(ppk[1]);
ppk[3] += RotR1(ppk[2]);
ppk[4] += RotR1(ppk[3]);
ppk[5] += RotR1(ppk[4]);

rc4key[0] = Hi8(tsc_IV16);
rc4key[1] = (Hi8(tsc_IV16) | 0x20) & 0x7f;
rc4key[2] = Lo8(tsc_IV16);
rc4key[3] = Lo8((ppk[5] ^ Mk16(tk[1], tk[0])) >> 1);

for (i = 0; i < 6; i++) {
rc4key[4 + 2 * i] = Lo8(ppk[i]);
rc4key[5 + 2 * i] = Hi8(ppk[i]);
}
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[0] = tsc_IV16 >> 8;
rc4key[1] = ((tsc_IV16 >> 8) | 0x20) & 0x7f;
rc4key[2] = tsc_IV16 & 0xFF;
rc4key[3] = ((ppk[5] ^ get_unaligned_le16(tk)) >> 1) & 0xFF;

rc4key += 4;
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). */
Expand All @@ -183,14 +139,10 @@ u8 * ieee80211_tkip_add_iv(u8 *pos, struct ieee80211_key *key,
*pos++ = iv1;
*pos++ = iv2;
*pos++ = (key->conf.keyidx << 6) | (1 << 5) /* Ext IV */;
*pos++ = key->u.tkip.iv32 & 0xff;
*pos++ = (key->u.tkip.iv32 >> 8) & 0xff;
*pos++ = (key->u.tkip.iv32 >> 16) & 0xff;
*pos++ = (key->u.tkip.iv32 >> 24) & 0xff;
return pos;
put_unaligned_le32(key->u.tkip.iv32, pos);
return pos + 4;
}


void ieee80211_tkip_gen_phase1key(struct ieee80211_key *key, u8 *ta,
u16 *phase1key)
{
Expand Down Expand Up @@ -228,10 +180,8 @@ void ieee80211_get_tkip_key(struct ieee80211_key_conf *keyconf,
u16 iv16;
u32 iv32;

iv16 = data[hdr_len] << 8;
iv16 += data[hdr_len + 2];
iv32 = data[hdr_len + 4] | (data[hdr_len + 5] << 8) |
(data[hdr_len + 6] << 16) | (data[hdr_len + 7] << 24);
iv16 = data[hdr_len + 2] | (data[hdr_len] << 8);
iv32 = get_unaligned_le32(data + hdr_len + 4);

#ifdef CONFIG_TKIP_DEBUG
printk(KERN_DEBUG "TKIP encrypt: iv16 = 0x%04x, iv32 = 0x%08x\n",
Expand Down Expand Up @@ -281,7 +231,6 @@ void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm,
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
Expand All @@ -302,7 +251,7 @@ int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,

iv16 = (pos[0] << 8) | pos[2];
keyid = pos[3];
iv32 = pos[4] | (pos[5] << 8) | (pos[6] << 16) | (pos[7] << 24);
iv32 = get_unaligned_le32(pos + 4);
pos += 8;
#ifdef CONFIG_TKIP_DEBUG
{
Expand Down Expand Up @@ -409,5 +358,3 @@ int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,

return res;
}


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