epan/crypt/dot11decrypt_tkip.c

   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 <wsutil/pint.h>
  13 #include <wsutil/crc32.h>
  14 #include "dot11decrypt_system.h"
  15 #include "dot11decrypt_int.h"
  16
  17 #include "dot11decrypt_debug.h"
  18 /*                                                                                                                                                                                                              */
  19 /******************************************************************************/
  20
  21 /******************************************************************************/
  22 /*      Internal definitions                                                                                                                                                    */
  23 /*                                                                                                                                                                                                              */
  24 #define PHASE1_LOOP_COUNT       8
  25
  26 #define DOT11DECRYPT_TTAK_LEN   6
  27 /*                                                                                                                                                                                                              */
  28 /******************************************************************************/
  29
  30 /******************************************************************************/
  31 /*      Internal function prototypes declarations                                                                                               */
  32 /*                                                                                                                                                                                                              */
  33 static void Dot11DecryptTkipMixingPhase1(
  34         UINT16 *TTAK,
  35         const UINT8 *TK,
  36         const UINT8 *TA,
  37         UINT32 TSC)
  38         ;
  39
  40 static void Dot11DecryptTkipMixingPhase2(
  41         UINT8 *wep_seed,
  42         const UINT8 *TK,
  43         UINT16 *PPK,
  44         UINT16 TSC16)
  45         ;
  46
  47 /*                                                                                                                                                                                                              */
  48 /******************************************************************************/
  49
  50 /******************************************************************************/
  51 /*      Global variables                                                                                                                                                                */
  52 /*                                                                                                                                                                                                              */
  53 /* Note: copied from FreeBSD source code, RELENG 6,                                                                     */
  54 /*              sys/net80211/ieee80211_crypto_tkip.c, 471                                                                                       */
  55 static const UINT16 Sbox[256] = {
  56         0xC6A5, 0xF884, 0xEE99, 0xF68D, 0xFF0D, 0xD6BD, 0xDEB1, 0x9154,
  57         0x6050, 0x0203, 0xCEA9, 0x567D, 0xE719, 0xB562, 0x4DE6, 0xEC9A,
  58         0x8F45, 0x1F9D, 0x8940, 0xFA87, 0xEF15, 0xB2EB, 0x8EC9, 0xFB0B,
  59         0x41EC, 0xB367, 0x5FFD, 0x45EA, 0x23BF, 0x53F7, 0xE496, 0x9B5B,
  60         0x75C2, 0xE11C, 0x3DAE, 0x4C6A, 0x6C5A, 0x7E41, 0xF502, 0x834F,
  61         0x685C, 0x51F4, 0xD134, 0xF908, 0xE293, 0xAB73, 0x6253, 0x2A3F,
  62         0x080C, 0x9552, 0x4665, 0x9D5E, 0x3028, 0x37A1, 0x0A0F, 0x2FB5,
  63         0x0E09, 0x2436, 0x1B9B, 0xDF3D, 0xCD26, 0x4E69, 0x7FCD, 0xEA9F,
  64         0x121B, 0x1D9E, 0x5874, 0x342E, 0x362D, 0xDCB2, 0xB4EE, 0x5BFB,
  65         0xA4F6, 0x764D, 0xB761, 0x7DCE, 0x527B, 0xDD3E, 0x5E71, 0x1397,
  66         0xA6F5, 0xB968, 0x0000, 0xC12C, 0x4060, 0xE31F, 0x79C8, 0xB6ED,
  67         0xD4BE, 0x8D46, 0x67D9, 0x724B, 0x94DE, 0x98D4, 0xB0E8, 0x854A,
  68         0xBB6B, 0xC52A, 0x4FE5, 0xED16, 0x86C5, 0x9AD7, 0x6655, 0x1194,
  69         0x8ACF, 0xE910, 0x0406, 0xFE81, 0xA0F0, 0x7844, 0x25BA, 0x4BE3,
  70         0xA2F3, 0x5DFE, 0x80C0, 0x058A, 0x3FAD, 0x21BC, 0x7048, 0xF104,
  71         0x63DF, 0x77C1, 0xAF75, 0x4263, 0x2030, 0xE51A, 0xFD0E, 0xBF6D,
  72         0x814C, 0x1814, 0x2635, 0xC32F, 0xBEE1, 0x35A2, 0x88CC, 0x2E39,
  73         0x9357, 0x55F2, 0xFC82, 0x7A47, 0xC8AC, 0xBAE7, 0x322B, 0xE695,
  74         0xC0A0, 0x1998, 0x9ED1, 0xA37F, 0x4466, 0x547E, 0x3BAB, 0x0B83,
  75         0x8CCA, 0xC729, 0x6BD3, 0x283C, 0xA779, 0xBCE2, 0x161D, 0xAD76,
  76         0xDB3B, 0x6456, 0x744E, 0x141E, 0x92DB, 0x0C0A, 0x486C, 0xB8E4,
  77         0x9F5D, 0xBD6E, 0x43EF, 0xC4A6, 0x39A8, 0x31A4, 0xD337, 0xF28B,
  78         0xD532, 0x8B43, 0x6E59, 0xDAB7, 0x018C, 0xB164, 0x9CD2, 0x49E0,
  79         0xD8B4, 0xACFA, 0xF307, 0xCF25, 0xCAAF, 0xF48E, 0x47E9, 0x1018,
  80         0x6FD5, 0xF088, 0x4A6F, 0x5C72, 0x3824, 0x57F1, 0x73C7, 0x9751,
  81         0xCB23, 0xA17C, 0xE89C, 0x3E21, 0x96DD, 0x61DC, 0x0D86, 0x0F85,
  82         0xE090, 0x7C42, 0x71C4, 0xCCAA, 0x90D8, 0x0605, 0xF701, 0x1C12,
  83         0xC2A3, 0x6A5F, 0xAEF9, 0x69D0, 0x1791, 0x9958, 0x3A27, 0x27B9,
  84         0xD938, 0xEB13, 0x2BB3, 0x2233, 0xD2BB, 0xA970, 0x0789, 0x33A7,
  85         0x2DB6, 0x3C22, 0x1592, 0xC920, 0x8749, 0xAAFF, 0x5078, 0xA57A,
  86         0x038F, 0x59F8, 0x0980, 0x1A17, 0x65DA, 0xD731, 0x84C6, 0xD0B8,
  87         0x82C3, 0x29B0, 0x5A77, 0x1E11, 0x7BCB, 0xA8FC, 0x6DD6, 0x2C3A,
  88 };
  89 /*                                                                                                                                                                                                              */
  90 /******************************************************************************/
  91
  92 /* TODO: check for little-endian, big-endian    */
  93
  94 /*                                                                                                                                                                                                              */
  95 /* Note: any functions were copied from FreeBSD source code, RELENG 6,                  */
  96 /*              sys/net80211/ieee80211_crypto_tkip.c                                                                                            */
  97 /* Converted to macros to avoid using __inline, as not all compilers support it */
  98 #define RotR1(val)      ((UINT16)(((val) >> 1) | ((val) << 15)))
  99
 100 #define Lo8(val)        ((UINT8)((val) & 0xff))
 101
 102 #define Hi8(val)        ((UINT8)((val) >> 8))
 103
 104 #define Lo16(val)       ((UINT16)((val) & 0xffff))
 105
 106 #define Hi16(val)       ((UINT16)((val) >> 16))
 107
 108 #define Mk16(hi, lo) \
 109         ((UINT16)((lo) | (((UINT16) (hi)) << 8)))
 110
 111 #define Mk16_le(v)      ((UINT16)pletoh16(v))
 112
 113 #define _S_(v) \
 114         ((UINT16)(Sbox[Lo8(v)] ^ ((Sbox[Hi8(v)] << 8) | (Sbox[Hi8(v)] >> 8))))
 115
 116 #define READ_6(b0, b1, b2, b3, b4, b5) \
 117         ((((UINT64)((UINT16)((b4 << 0) | (b5 << 8)))) << 32) | \
 118             ((UINT32)((b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24))))
 119
 120 /******************************************************************************/
 121 /*      Function definitions                                                                                                                                                    */
 122
 123 static void Dot11DecryptTkipMixingPhase1(
 124         UINT16 *TTAK,
 125         const UINT8 *TK,
 126         const UINT8 *TA,
 127         UINT32 TSC)
 128 {
 129         UINT16 i, j;
 130
 131         /* Initialize the 80-bit TTAK from TSC (TSC) and TA[0..5] */
 132         TTAK[0] = Lo16(TSC);
 133         TTAK[1] = Hi16(TSC);
 134         TTAK[2] = Mk16(TA[1], TA[0]);
 135         TTAK[3] = Mk16(TA[3], TA[2]);
 136         TTAK[4] = Mk16(TA[5], TA[4]);
 137
 138         for (i = 0; i < PHASE1_LOOP_COUNT; i++) {
 139                 j = (UINT16)(2 * (i & 1));
 140                 TTAK[0] = (UINT16)(TTAK[0] + _S_((UINT16)(TTAK[4] ^ Mk16(TK[1 + j], TK[0 + j]))));
 141                 TTAK[1] = (UINT16)(TTAK[1] + _S_((UINT16)(TTAK[0] ^ Mk16(TK[5 + j], TK[4 + j]))));
 142                 TTAK[2] = (UINT16)(TTAK[2] + _S_((UINT16)(TTAK[1] ^ Mk16(TK[9 + j], TK[8 + j]))));
 143                 TTAK[3] = (UINT16)(TTAK[3] + _S_((UINT16)(TTAK[2] ^ Mk16(TK[13 + j], TK[12 + j]))));
 144                 TTAK[4] = (UINT16)(TTAK[4] + _S_((UINT16)(TTAK[3] ^ Mk16(TK[1 + j], TK[0 + j]))) + i);
 145         }
 146 }
 147
 148 static void Dot11DecryptTkipMixingPhase2(
 149         UINT8 *wep_seed,
 150         const UINT8 *TK,
 151         UINT16 *TTAK,
 152         UINT16 TSC16)
 153 {
 154         INT i;
 155         TTAK[5] = (UINT16)(TTAK[4] + TSC16);
 156
 157         /* Step 2 - 96-bit bijective mixing using S-box */
 158         TTAK[0] = (UINT16)(TTAK[0] + _S_((UINT16)(TTAK[5] ^ Mk16_le(&TK[0]))));
 159         TTAK[1] = (UINT16)(TTAK[1] + _S_((UINT16)(TTAK[0] ^ Mk16_le(&TK[2]))));
 160         TTAK[2] = (UINT16)(TTAK[2] + _S_((UINT16)(TTAK[1] ^ Mk16_le(&TK[4]))));
 161         TTAK[3] = (UINT16)(TTAK[3] + _S_((UINT16)(TTAK[2] ^ Mk16_le(&TK[6]))));
 162         TTAK[4] = (UINT16)(TTAK[4] + _S_((UINT16)(TTAK[3] ^ Mk16_le(&TK[8]))));
 163         TTAK[5] = (UINT16)(TTAK[5] + _S_((UINT16)(TTAK[4] ^ Mk16_le(&TK[10]))));
 164
 165         TTAK[0] = (UINT16)(TTAK[0] + RotR1((UINT16)(TTAK[5] ^ Mk16_le(&TK[12]))));
 166         TTAK[1] = (UINT16)(TTAK[1] + RotR1((UINT16)(TTAK[0] ^ Mk16_le(&TK[14]))));
 167         TTAK[2] = (UINT16)(TTAK[2] + RotR1(TTAK[1]));
 168         TTAK[3] = (UINT16)(TTAK[3] + RotR1(TTAK[2]));
 169         TTAK[4] = (UINT16)(TTAK[4] + RotR1(TTAK[3]));
 170         TTAK[5] = (UINT16)(TTAK[5] + RotR1(TTAK[4]));
 171
 172         /* Step 3 - bring in last of TK bits, assign 24-bit WEP IV value
 173         * wep_seed[0..2] is transmitted as WEP IV */
 174         wep_seed[0] = Hi8(TSC16);
 175         wep_seed[1] = (UINT8)((Hi8(TSC16) | 0x20) & 0x7F);
 176         wep_seed[2] = Lo8(TSC16);
 177         wep_seed[3] = Lo8((UINT16)((TTAK[5] ^ Mk16_le(&TK[0])) >> 1));
 178
 179         for (i = 0; i < 6; i++)
 180         {
 181                 wep_seed[4 + ( 2 * i)] = Lo8( TTAK[i] );
 182                 wep_seed[5 + ( 2 * i)] = Hi8( TTAK[i] );
 183         }
 184 }
 185
 186 /* Note: taken from FreeBSD source code, RELENG 6,                                                                              */
 187 /*              sys/net80211/ieee80211_crypto_tkip.c, 936                                                                                       */
 188 INT Dot11DecryptTkipDecrypt(
 189         UCHAR *tkip_mpdu,
 190         size_t mpdu_len,
 191         UCHAR TA[DOT11DECRYPT_MAC_LEN],
 192         UCHAR TK[DOT11DECRYPT_TK_LEN])
 193 {
 194         UINT64 TSC64;
 195         UINT32 TSC;
 196         UINT16 TSC16;
 197         UINT8 *IV;
 198         UINT16 TTAK[DOT11DECRYPT_TTAK_LEN];
 199         UINT8 wep_seed[DOT11DECRYPT_WEP_128_KEY_LEN];
 200
 201         /* DEBUG_DUMP("TA", TA, 6); */
 202
 203         IV = tkip_mpdu;
 204
 205         TSC64 = READ_6(IV[2], IV[0], IV[4], IV[5], IV[6], IV[7]);
 206         TSC16 = (UINT16)TSC64;
 207
 208         /* The original code made no sense!!  We were shifting a 16-bit number 16 bits to the right. */
 209         /* We instead have to have READ_6() be returned to a UINT64 and shift *that* value. */
 210         TSC = (UINT32)(TSC64 >> 16);
 211
 212         Dot11DecryptTkipMixingPhase1(TTAK, TK, TA, TSC);
 213
 214         Dot11DecryptTkipMixingPhase2(wep_seed, TK, TTAK, TSC16);
 215
 216         return Dot11DecryptWepDecrypt(
 217                 wep_seed,
 218                 DOT11DECRYPT_WEP_128_KEY_LEN,
 219                 tkip_mpdu + DOT11DECRYPT_TKIP_HEADER,
 220                 mpdu_len-(DOT11DECRYPT_TKIP_HEADER+DOT11DECRYPT_WEP_ICV));      /* MPDU - TKIP_HEADER - MIC     */
 221
 222         /* TODO check (IEEE 802.11i-2004, pg. 44)                                                                                               */
 223
 224 }
 225 /*                                                                                                                                                                                                              */
 226 /******************************************************************************/