/src/wireshark/epan/crypt/dot11decrypt_tkip.c

Source
/*
 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
 * Copyright (c) 2006 CACE Technologies, Davis (California)
 * All rights reserved.
 *
 * SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0-only)
 */

/******************************************************************************/
/*  File includes                                         */
/*                                                    */
#include "dot11decrypt_debug.h"
#include <wsutil/pint.h>
#include "dot11decrypt_system.h"
#include "dot11decrypt_int.h"

/*                                                    */
/******************************************************************************/

/******************************************************************************/
/*  Internal definitions                                      */
/*                                                    */
#define PHASE1_LOOP_COUNT 8

#define DOT11DECRYPT_TTAK_LEN 6
/*                                                    */
/******************************************************************************/

/******************************************************************************/
/*  Internal function prototypes declarations                       */
/*                                                    */
static void Dot11DecryptTkipMixingPhase1(
  uint16_t *TTAK,
  const uint8_t *TK,
  const uint8_t *TA,
  uint32_t TSC)
  ;

static void Dot11DecryptTkipMixingPhase2(
  uint8_t *wep_seed,
  const uint8_t *TK,
  uint16_t *PPK,
  uint16_t TSC16)
  ;

/*                                                    */
/******************************************************************************/

/******************************************************************************/
/*  Global variables                                        */
/*                                                    */
/* Note: copied from FreeBSD source code, RELENG 6,                 */
/*    sys/net80211/ieee80211_crypto_tkip.c, 471                     */
static const uint16_t 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,
};
/*                                                    */
/******************************************************************************/

/* TODO: check for little-endian, big-endian  */

/*                                                    */
/* Note: any functions were copied from FreeBSD source code, RELENG 6,      */
/*    sys/net80211/ieee80211_crypto_tkip.c                        */
/* Converted to macros to avoid using __inline, as not all compilers support it */
#define RotR1(val)  ((uint16_t)(((val) >> 1) | ((val) << 15)))

#define Lo8(val)  ((uint8_t)((val) & 0xff))

#define Hi8(val)  ((uint8_t)((val) >> 8))

#define Lo16(val) ((uint16_t)((val) & 0xffff))

#define Hi16(val) ((uint16_t)((val) >> 16))

#define Mk16(hi, lo) \
  ((uint16_t)((lo) | (((uint16_t) (hi)) << 8)))

#define Mk16_le(v)  ((uint16_t)pletohu16(v))

#define _S_(v) \
  ((uint16_t)(Sbox[Lo8(v)] ^ ((Sbox[Hi8(v)] << 8) | (Sbox[Hi8(v)] >> 8))))

#define READ_6(b0, b1, b2, b3, b4, b5) \
  ((((uint64_t)((uint16_t)((b4 << 0) | (b5 << 8)))) << 32) | \
      ((uint32_t)((b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24))))

/******************************************************************************/
/*  Function definitions                                      */

static void Dot11DecryptTkipMixingPhase1(
  uint16_t *TTAK,
  const uint8_t *TK,
  const uint8_t *TA,
  uint32_t TSC)
{
  uint16_t i, j;

  /* Initialize the 80-bit TTAK from TSC (TSC) and TA[0..5] */
  TTAK[0] = Lo16(TSC);
  TTAK[1] = Hi16(TSC);
  TTAK[2] = Mk16(TA[1], TA[0]);
  TTAK[3] = Mk16(TA[3], TA[2]);
  TTAK[4] = Mk16(TA[5], TA[4]);

  for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
    j = (uint16_t)(2 * (i & 1));
    TTAK[0] = (uint16_t)(TTAK[0] + _S_((uint16_t)(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]))));
    TTAK[1] = (uint16_t)(TTAK[1] + _S_((uint16_t)(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]))));
    TTAK[2] = (uint16_t)(TTAK[2] + _S_((uint16_t)(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]))));
    TTAK[3] = (uint16_t)(TTAK[3] + _S_((uint16_t)(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]))));
    TTAK[4] = (uint16_t)(TTAK[4] + _S_((uint16_t)(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j]))) + i);
  }
}

static void Dot11DecryptTkipMixingPhase2(
  uint8_t *wep_seed,
  const uint8_t *TK,
  uint16_t *TTAK,
  uint16_t TSC16)
{
  int i;
  TTAK[5] = (uint16_t)(TTAK[4] + TSC16);

  /* Step 2 - 96-bit bijective mixing using S-box */
  TTAK[0] = (uint16_t)(TTAK[0] + _S_((uint16_t)(TTAK[5] ^ Mk16_le(&TK[0]))));
  TTAK[1] = (uint16_t)(TTAK[1] + _S_((uint16_t)(TTAK[0] ^ Mk16_le(&TK[2]))));
  TTAK[2] = (uint16_t)(TTAK[2] + _S_((uint16_t)(TTAK[1] ^ Mk16_le(&TK[4]))));
  TTAK[3] = (uint16_t)(TTAK[3] + _S_((uint16_t)(TTAK[2] ^ Mk16_le(&TK[6]))));
  TTAK[4] = (uint16_t)(TTAK[4] + _S_((uint16_t)(TTAK[3] ^ Mk16_le(&TK[8]))));
  TTAK[5] = (uint16_t)(TTAK[5] + _S_((uint16_t)(TTAK[4] ^ Mk16_le(&TK[10]))));

  TTAK[0] = (uint16_t)(TTAK[0] + RotR1((uint16_t)(TTAK[5] ^ Mk16_le(&TK[12]))));
  TTAK[1] = (uint16_t)(TTAK[1] + RotR1((uint16_t)(TTAK[0] ^ Mk16_le(&TK[14]))));
  TTAK[2] = (uint16_t)(TTAK[2] + RotR1(TTAK[1]));
  TTAK[3] = (uint16_t)(TTAK[3] + RotR1(TTAK[2]));
  TTAK[4] = (uint16_t)(TTAK[4] + RotR1(TTAK[3]));
  TTAK[5] = (uint16_t)(TTAK[5] + RotR1(TTAK[4]));

  /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
  * wep_seed[0..2] is transmitted as WEP IV */
  wep_seed[0] = Hi8(TSC16);
  wep_seed[1] = (uint8_t)((Hi8(TSC16) | 0x20) & 0x7F);
  wep_seed[2] = Lo8(TSC16);
  wep_seed[3] = Lo8((uint16_t)((TTAK[5] ^ Mk16_le(&TK[0])) >> 1));

  for (i = 0; i < 6; i++)
  {
    wep_seed[4 + ( 2 * i)] = Lo8( TTAK[i] );
    wep_seed[5 + ( 2 * i)] = Hi8( TTAK[i] );
  }
}

/* Note: taken from FreeBSD source code, RELENG 6,                    */
/*    sys/net80211/ieee80211_crypto_tkip.c, 936                     */
int Dot11DecryptTkipDecrypt(
  uint8_t *mpdu,
  size_t mac_header_len,
  size_t mpdu_len,
  unsigned char TK[DOT11DECRYPT_TK_LEN])
{
  uint64_t TSC64;
  uint32_t TSC;
  uint16_t TSC16;
  uint8_t *IV;
  uint16_t TTAK[DOT11DECRYPT_TTAK_LEN];
  uint8_t wep_seed[DOT11DECRYPT_WEP_128_KEY_LEN];
  ssize_t decrypt_len = (ssize_t)mpdu_len -
                        (ssize_t)(mac_header_len + DOT11DECRYPT_TKIP_HEADER + DOT11DECRYPT_WEP_ICV);
  const uint8_t *TA;

  if (decrypt_len < 1) {
      return -1;
  }

  TA = mpdu + DOT11DECRYPT_TA_OFFSET;
  IV = mpdu + mac_header_len;

  TSC64 = READ_6(IV[2], IV[0], IV[4], IV[5], IV[6], IV[7]);
  TSC16 = (uint16_t)TSC64;

  /* The original code made no sense!!  We were shifting a 16-bit number 16 bits to the right. */
  /* We instead have to have READ_6() be returned to a uint64_t and shift *that* value. */
  TSC = (uint32_t)(TSC64 >> 16);

  Dot11DecryptTkipMixingPhase1(TTAK, TK, TA, TSC);

  Dot11DecryptTkipMixingPhase2(wep_seed, TK, TTAK, TSC16);

  if (Dot11DecryptWepDecrypt(
    wep_seed,
    DOT11DECRYPT_WEP_128_KEY_LEN,
    IV + DOT11DECRYPT_TKIP_HEADER,
    decrypt_len)) {
    return 1;
  }

  /* TODO check (IEEE 802.11i-2004, pg. 44)                       */

  return 0;
}
/*                                                    */
/******************************************************************************/

Coverage Report

Created: 2026-05-14 06:28

Line	Count	Source
1		/*
2		* Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
3		* Copyright (c) 2006 CACE Technologies, Davis (California)
4		* All rights reserved.
5		*
6		* SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0-only)
7		*/
8
9		/******************************************************************************/
10		/* File includes */
11		/* */
12		#include "dot11decrypt_debug.h"
13		#include <wsutil/pint.h>
14		#include "dot11decrypt_system.h"
15		#include "dot11decrypt_int.h"
16
17		/* */
18		/******************************************************************************/
19
20		/******************************************************************************/
21		/* Internal definitions */
22		/* */
23	0	#define PHASE1_LOOP_COUNT 8
24
25		#define DOT11DECRYPT_TTAK_LEN 6
26		/* */
27		/******************************************************************************/
28
29		/******************************************************************************/
30		/* Internal function prototypes declarations */
31		/* */
32		static void Dot11DecryptTkipMixingPhase1(
33		uint16_t *TTAK,
34		const uint8_t *TK,
35		const uint8_t *TA,
36		uint32_t TSC)
37		;
38
39		static void Dot11DecryptTkipMixingPhase2(
40		uint8_t *wep_seed,
41		const uint8_t *TK,
42		uint16_t *PPK,
43		uint16_t TSC16)
44		;
45
46		/* */
47		/******************************************************************************/
48
49		/******************************************************************************/
50		/* Global variables */
51		/* */
52		/* Note: copied from FreeBSD source code, RELENG 6, */
53		/* sys/net80211/ieee80211_crypto_tkip.c, 471 */
54		static const uint16_t Sbox[256] = {
55		0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
56		0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
57		0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
58		0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
59		0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
60		0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
61		0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
62		0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
63		0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
64		0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
65		0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
66		0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
67		0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
68		0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
69		0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
70		0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
71		0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
72		0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
73		0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
74		0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
75		0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
76		0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
77		0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
78		0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
79		0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
80		0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
81		0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
82		0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
83		0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
84		0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
85		0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
86		0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
87		};
88		/* */
89		/******************************************************************************/
90
91		/* TODO: check for little-endian, big-endian */
92
93		/* */
94		/* Note: any functions were copied from FreeBSD source code, RELENG 6, */
95		/* sys/net80211/ieee80211_crypto_tkip.c */
96		/* Converted to macros to avoid using __inline, as not all compilers support it */
97	0	#define RotR1(val) ((uint16_t)(((val) >> 1) \| ((val) << 15)))
98
99	0	#define Lo8(val) ((uint8_t)((val) & 0xff))
100
101	0	#define Hi8(val) ((uint8_t)((val) >> 8))
102
103	0	#define Lo16(val) ((uint16_t)((val) & 0xffff))
104
105	0	#define Hi16(val) ((uint16_t)((val) >> 16))
106
107		#define Mk16(hi, lo) \
108	0	((uint16_t)((lo) \| (((uint16_t) (hi)) << 8)))
109
110		#define Mk16_le(v) ((uint16_t)pletohu16(v))
111
112		#define _S_(v) \
113	0	((uint16_t)(Sbox[Lo8(v)] ^ ((Sbox[Hi8(v)] << 8) \| (Sbox[Hi8(v)] >> 8))))
114
115		#define READ_6(b0, b1, b2, b3, b4, b5) \
116	0	((((uint64_t)((uint16_t)((b4 << 0) \| (b5 << 8)))) << 32) \| \
117	0	((uint32_t)((b0 << 0) \| (b1 << 8) \| (b2 << 16) \| (b3 << 24))))
118
119		/******************************************************************************/
120		/* Function definitions */
121
122		static void Dot11DecryptTkipMixingPhase1(
123		uint16_t *TTAK,
124		const uint8_t *TK,
125		const uint8_t *TA,
126		uint32_t TSC)
127	0	{
128	0	uint16_t i, j;
129
130		/* Initialize the 80-bit TTAK from TSC (TSC) and TA[0..5] */
131	0	TTAK[0] = Lo16(TSC);
132	0	TTAK[1] = Hi16(TSC);
133	0	TTAK[2] = Mk16(TA[1], TA[0]);
134	0	TTAK[3] = Mk16(TA[3], TA[2]);
135	0	TTAK[4] = Mk16(TA[5], TA[4]);
136
137	0	for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
138	0	j = (uint16_t)(2 * (i & 1));
139	0	TTAK[0] = (uint16_t)(TTAK[0] + _S_((uint16_t)(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]))));
140	0	TTAK[1] = (uint16_t)(TTAK[1] + _S_((uint16_t)(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]))));
141	0	TTAK[2] = (uint16_t)(TTAK[2] + _S_((uint16_t)(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]))));
142	0	TTAK[3] = (uint16_t)(TTAK[3] + _S_((uint16_t)(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]))));
143	0	TTAK[4] = (uint16_t)(TTAK[4] + _S_((uint16_t)(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j]))) + i);
144	0	}
145	0	}
146
147		static void Dot11DecryptTkipMixingPhase2(
148		uint8_t *wep_seed,
149		const uint8_t *TK,
150		uint16_t *TTAK,
151		uint16_t TSC16)
152	0	{
153	0	int i;
154	0	TTAK[5] = (uint16_t)(TTAK[4] + TSC16);
155
156		/* Step 2 - 96-bit bijective mixing using S-box */
157	0	TTAK[0] = (uint16_t)(TTAK[0] + _S_((uint16_t)(TTAK[5] ^ Mk16_le(&TK[0]))));
158	0	TTAK[1] = (uint16_t)(TTAK[1] + _S_((uint16_t)(TTAK[0] ^ Mk16_le(&TK[2]))));
159	0	TTAK[2] = (uint16_t)(TTAK[2] + _S_((uint16_t)(TTAK[1] ^ Mk16_le(&TK[4]))));
160	0	TTAK[3] = (uint16_t)(TTAK[3] + _S_((uint16_t)(TTAK[2] ^ Mk16_le(&TK[6]))));
161	0	TTAK[4] = (uint16_t)(TTAK[4] + _S_((uint16_t)(TTAK[3] ^ Mk16_le(&TK[8]))));
162	0	TTAK[5] = (uint16_t)(TTAK[5] + _S_((uint16_t)(TTAK[4] ^ Mk16_le(&TK[10]))));
163
164	0	TTAK[0] = (uint16_t)(TTAK[0] + RotR1((uint16_t)(TTAK[5] ^ Mk16_le(&TK[12]))));
165	0	TTAK[1] = (uint16_t)(TTAK[1] + RotR1((uint16_t)(TTAK[0] ^ Mk16_le(&TK[14]))));
166	0	TTAK[2] = (uint16_t)(TTAK[2] + RotR1(TTAK[1]));
167	0	TTAK[3] = (uint16_t)(TTAK[3] + RotR1(TTAK[2]));
168	0	TTAK[4] = (uint16_t)(TTAK[4] + RotR1(TTAK[3]));
169	0	TTAK[5] = (uint16_t)(TTAK[5] + RotR1(TTAK[4]));
170
171		/* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
172		* wep_seed[0..2] is transmitted as WEP IV */
173	0	wep_seed[0] = Hi8(TSC16);
174	0	wep_seed[1] = (uint8_t)((Hi8(TSC16) \| 0x20) & 0x7F);
175	0	wep_seed[2] = Lo8(TSC16);
176	0	wep_seed[3] = Lo8((uint16_t)((TTAK[5] ^ Mk16_le(&TK[0])) >> 1));
177
178	0	for (i = 0; i < 6; i++)
179	0	{
180	0	wep_seed[4 + ( 2 * i)] = Lo8( TTAK[i] );
181	0	wep_seed[5 + ( 2 * i)] = Hi8( TTAK[i] );
182	0	}
183	0	}
184
185		/* Note: taken from FreeBSD source code, RELENG 6, */
186		/* sys/net80211/ieee80211_crypto_tkip.c, 936 */
187		int Dot11DecryptTkipDecrypt(
188		uint8_t *mpdu,
189		size_t mac_header_len,
190		size_t mpdu_len,
191		unsigned char TK[DOT11DECRYPT_TK_LEN])
192	0	{
193	0	uint64_t TSC64;
194	0	uint32_t TSC;
195	0	uint16_t TSC16;
196	0	uint8_t *IV;
197	0	uint16_t TTAK[DOT11DECRYPT_TTAK_LEN];
198	0	uint8_t wep_seed[DOT11DECRYPT_WEP_128_KEY_LEN];
199	0	ssize_t decrypt_len = (ssize_t)mpdu_len -
200	0	(ssize_t)(mac_header_len + DOT11DECRYPT_TKIP_HEADER + DOT11DECRYPT_WEP_ICV);
201	0	const uint8_t *TA;
202
203	0	if (decrypt_len < 1) {
204	0	return -1;
205	0	}
206
207	0	TA = mpdu + DOT11DECRYPT_TA_OFFSET;
208	0	IV = mpdu + mac_header_len;
209
210	0	TSC64 = READ_6(IV[2], IV[0], IV[4], IV[5], IV[6], IV[7]);
211	0	TSC16 = (uint16_t)TSC64;
212
213		/* The original code made no sense!! We were shifting a 16-bit number 16 bits to the right. */
214		/* We instead have to have READ_6() be returned to a uint64_t and shift that value. */
215	0	TSC = (uint32_t)(TSC64 >> 16);
216
217	0	Dot11DecryptTkipMixingPhase1(TTAK, TK, TA, TSC);
218
219	0	Dot11DecryptTkipMixingPhase2(wep_seed, TK, TTAK, TSC16);
220
221	0	if (Dot11DecryptWepDecrypt(
222	0	wep_seed,
223	0	DOT11DECRYPT_WEP_128_KEY_LEN,
224	0	IV + DOT11DECRYPT_TKIP_HEADER,
225	0	decrypt_len)) {
226	0	return 1;
227	0	}
228
229		/* TODO check (IEEE 802.11i-2004, pg. 44) */
230
231	0	return 0;
232	0	}
233		/* */
234		/******************************************************************************/