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/*
* Copyright (C) 2008-2018 TrinityCore <https://www.trinitycore.org/>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "TOTP.h"
#include <cstring>
int base32_decode(char const* encoded, char* result, int bufSize)
{
// Base32 implementation
// Copyright 2010 Google Inc.
// Author: Markus Gutschke
// Licensed under the Apache License, Version 2.0
int buffer = 0;
int bitsLeft = 0;
int count = 0;
for (const char *ptr = encoded; count < bufSize && *ptr; ++ptr)
{
char ch = *ptr;
if (ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n' || ch == '-')
continue;
buffer <<= 5;
// Deal with commonly mistyped characters
if (ch == '0')
ch = 'O';
else if (ch == '1')
ch = 'L';
else if (ch == '8')
ch = 'B';
// Look up one base32 digit
if ((ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z'))
ch = (ch & 0x1F) - 1;
else if (ch >= '2' && ch <= '7')
ch -= '2' - 26;
else
return -1;
buffer |= ch;
bitsLeft += 5;
if (bitsLeft >= 8)
{
result[count++] = buffer >> (bitsLeft - 8);
bitsLeft -= 8;
}
}
if (count < bufSize)
result[count] = '\000';
return count;
}
#define HMAC_RES_SIZE 20
namespace TOTP
{
unsigned int GenerateToken(char const* b32key)
{
size_t keySize = strlen(b32key);
int bufsize = (keySize + 7)/8*5;
char* encoded = new char[bufsize];
memset(encoded, 0, bufsize);
unsigned int hmacResSize = HMAC_RES_SIZE;
unsigned char hmacRes[HMAC_RES_SIZE];
unsigned long timestamp = time(nullptr)/30;
unsigned char challenge[8];
for (int i = 8; i--;timestamp >>= 8)
challenge[i] = timestamp;
base32_decode(b32key, encoded, bufsize);
HMAC(EVP_sha1(), encoded, bufsize, challenge, 8, hmacRes, &hmacResSize);
unsigned int offset = hmacRes[19] & 0xF;
unsigned int truncHash = (hmacRes[offset] << 24) | (hmacRes[offset+1] << 16 )| (hmacRes[offset+2] << 8) | (hmacRes[offset+3]);
truncHash &= 0x7FFFFFFF;
delete[] encoded;
return truncHash % 1000000;
}
}
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