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/*
* WALogin.cpp
*
* Created on: 26/06/2012
* Author: Antonio
*/
#include "../common.h" // #TODO Remove Miranda-dependency
#include "WALogin.h"
#include "ByteArray.h"
#include "ProtocolTreeNode.h"
#include "WAException.h"
using namespace Utilities;
KeyStream::KeyStream() :
seq(0)
{
HMAC_CTX_init(&hmac);
}
KeyStream::~KeyStream()
{
HMAC_CTX_cleanup(&hmac);
}
void KeyStream::init(unsigned char* _key, unsigned char* _keyMac)
{
memcpy(key, _key, 20);
memcpy(keyMac, _keyMac, 20);
RC4_set_key(&this->rc4, 20, this->key);
unsigned char drop[768];
RC4(&this->rc4, sizeof(drop), drop, drop);
}
void KeyStream::keyFromPasswordAndNonce(const std::string &pass, const std::vector<unsigned char>& nonce, unsigned char *out)
{
size_t cbSize = nonce.size();
uint8_t *pNonce = (uint8_t*)_alloca(cbSize + 1);
memcpy(pNonce, nonce.data(), cbSize);
for (int i = 0; i < 4; i++) {
pNonce[cbSize] = i + 1;
PKCS5_PBKDF2_HMAC_SHA1(pass.data(), (int)pass.size(), pNonce, (int)cbSize+1, 2, 20, out + i*20);
}
}
void KeyStream::decodeMessage(unsigned char* buffer, int macOffset, int offset, const int length)
{
unsigned char digest[20];
this->hmacsha1(buffer + offset, length, digest);
if (memcmp(&buffer[macOffset], digest, 4))
throw WAException("invalid MAC", WAException::CORRUPT_STREAM_EX, 0);
unsigned char* out = (unsigned char*)_alloca(length);
RC4(&this->rc4, length, buffer + offset, out);
memcpy(buffer + offset, out, length);
}
void KeyStream::encodeMessage(unsigned char* buffer, int macOffset, int offset, const int length)
{
unsigned char* out = (unsigned char*)_alloca(length);
RC4(&this->rc4, length, buffer + offset, out);
memcpy(buffer + offset, out, length);
unsigned char digest[20];
this->hmacsha1(buffer + offset, length, digest);
memcpy(buffer + macOffset, digest, 4);
}
void KeyStream::hmacsha1(unsigned char* text, int textLength, unsigned char *out)
{
HMAC_Init(&hmac, this->keyMac, 20, EVP_sha1());
HMAC_Update(&hmac, text, textLength);
unsigned char hmacInt[4];
hmacInt[0] = (this->seq >> 24);
hmacInt[1] = (this->seq >> 16);
hmacInt[2] = (this->seq >> 8);
hmacInt[3] = (this->seq);
HMAC_Update(&hmac, hmacInt, sizeof(hmacInt));
unsigned int mdLength;
HMAC_Final(&hmac, out, &mdLength);
this->seq++;
}
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