C++ - 绕过 WinSock Hook

Question

我想做的是使用 the Detours library连接到应用程序 WinSock2 send() 和 recv() 函数(数据包记录器)。

虽然它确实适用于 send() 函数，但它不适用于 recv() 函数。

这是我的相关代码:

#include <cstdio>
#include <ctime>
#include <fstream>
#include <iomanip>
#include <string>
#include <windows.h>
#include <detours.h>

#pragma comment( lib, "Ws2_32.lib" )
#pragma comment( lib, "detours.lib" )
#pragma comment( lib, "detoured.lib" )
#pragma comment( lib, "Mswsock.lib" )

std::ofstream Logger;

std::string NowToString() {
    time_t rawtime;
    tm *timeinfo = new tm();
    char buffer[32];

    time( &rawtime );
    localtime_s( timeinfo, &rawtime );

    strftime( buffer, 32, "%m/%d/%Y %I:%M:%S %p", timeinfo );

    delete timeinfo;

    return std::string( buffer );
}

std::string TimeToString() {
    time_t rawtime;
    tm *timeinfo = new tm();
    char buffer[32];

    time( &rawtime );
    localtime_s( timeinfo, &rawtime );

    strftime( buffer, 32, "%I:%M:%S %p", timeinfo );

    delete timeinfo;

    return std::string( buffer );
}

void LogPacket( const char *buf, int len ) {
    Logger << "        0  1  2  3  4  5  6  7   8  9  A  B  C  D  E  F\n";
    Logger << "       -- -- -- -- -- -- -- --  -- -- -- -- -- -- -- --\n";
    Logger << "0000   ";

    for ( int i = 0; i < len; ++i ) {
        if ( i != 0 && i % 16 == 0 ) {
            Logger << "  ";

            int line = ( i / 16 ) - 1;

            for ( int j = 0; j < 16; ++j ) {
                char c = buf[line * 16 + j];

                if ( c >= 32 && c <= 126 ) {
                    Logger << c;
                } else {
                    Logger << '.';
                }
            }

            Logger << "\n" << std::hex << std::setw( 4 ) << std::setfill( '0' ) << i << std::dec << std::setw( 0 ) << "   ";
        } else if ( i % 16 == 8 ) {
            Logger << ' ';
        }

        Logger << std::hex << std::setw( 2 ) << std::setfill( '0' ) << ( int( buf[i] ) & 0xFF ) << ' ';
        Logger << std::dec << std::setw( 0 );

        if ( i == len - 1 ) {
            int remaining = 16 - ( len % 16 );
            int fill = ( remaining * 3 ) + 2;

            if ( remaining >= 8 ) {
                ++fill;
            }

            for ( int j = 0; j < fill; ++j ) {
                Logger << ' ';
            }

            int line = ( i - ( ( len % 16 ) - 1 ) ) / 16 ;

            for ( int k = 0; k < ( len % 16 ); ++k ) {
                char c = buf[line * 16 + k];

                if ( c >= 32 && c <= 126 ) {
                    Logger << c;
                } else {
                    Logger << '.';
                }
            }
        }
    }

    Logger << "\n\n";
}

int ( WINAPI *Real_Send )( SOCKET s, const char *buf, int len, int flags ) = send;
int ( WINAPI *Real_Recv )( SOCKET s, char *buf, int len, int flags ) = recv;
int ( WINAPI *Real_RecvFrom )( SOCKET s, char *buf, int len, int flags, sockaddr *from, int *fromlen ) = recvfrom;
int ( WINAPI *Real_WSARecvEx )( SOCKET s, char *buf, int len, int *flags ) = WSARecvEx;

int WINAPI Mine_Send( SOCKET s, const char* buf, int len, int flags );
int WINAPI Mine_Recv( SOCKET s, char *buf, int len, int flags );
int WINAPI Mine_RecvFrom( SOCKET s, char *buf, int len, int flags, sockaddr *from, int *fromlen );
int WINAPI Mine_WSARecvEx( SOCKET s, char *buf, int len, int *flags );

int WINAPI Mine_Send( SOCKET s, const char *buf, int len, int flags ) {
    Logger << TimeToString() << ": Client -> Server (Length: " << len << " bytes)\n\n";
    LogPacket( buf, len );
    Logger << std::endl;

    return Real_Send( s, buf, len, flags );
}

int WINAPI Mine_Recv( SOCKET s, char *buf, int len, int flags ) {
    Logger << TimeToString() << ": Server -> Client (Length: " << len << " bytes)\n\n";
    LogPacket( buf, len );
    Logger << std::endl;

    return Real_Recv( s, buf, len, flags );
}

int WINAPI Mine_RecvFrom( SOCKET s, char *buf, int len, int flags, sockaddr *from, int *fromlen ) {
    Logger << TimeToString() << ": Server -> Client (Length: " << len << " bytes)*\n\n";
    LogPacket( buf, len );
    Logger << std::endl;

    return Real_RecvFrom( s, buf, len, flags, from, fromlen );
}

int WINAPI Mine_WSARecvEx( SOCKET s, char *buf, int len, int *flags ) {
    Logger << TimeToString() << ": Server -> Client (Length: " << len << " bytes)**\n\n";
    LogPacket( buf, len );
    Logger << std::endl;

    return Real_WSARecvEx( s, buf, len, flags );
}

BOOL WINAPI DllMain( HINSTANCE, DWORD dwReason, LPVOID ) {
    switch ( dwReason ) {
        case DLL_PROCESS_ATTACH:    
            Logger.open( "C:\\Packets.txt", std::ios::out | std::ios::app | std::ios::ate );

            if ( Logger.tellp() > 0 ) {
                Logger << "\n\n\n";
            }

            Logger << "##\n## Logging Started (" << NowToString() << ")\n##\n\n\n";

            DetourTransactionBegin();
            DetourUpdateThread( GetCurrentThread() );
            DetourAttach( &(PVOID &)Real_Send, Mine_Send );
            DetourAttach( &(PVOID &)Real_Recv, Mine_Recv );
            DetourAttach( &(PVOID &)Real_RecvFrom, Mine_RecvFrom );
            DetourAttach( &(PVOID &)Real_WSARecvEx, Mine_WSARecvEx );
            DetourTransactionCommit();

            break;

        case DLL_PROCESS_DETACH:
            Logger << "##\n## Logging Stopped (" << NowToString() << ")\n##";
            Logger.close();

            DetourTransactionBegin();
            DetourUpdateThread( GetCurrentThread() );
            DetourDetach( &(PVOID &)Real_Send, Mine_Send );
            DetourDetach( &(PVOID &)Real_Recv, Mine_Recv );
            DetourDetach( &(PVOID &)Real_RecvFrom, Mine_RecvFrom );
            DetourDetach( &(PVOID &)Real_WSARecvEx, Mine_WSARecvEx );
            DetourTransactionCommit();

            break;
    }

    return TRUE;
}

有什么想法吗？

编辑: 所以我已经连接了 recvfrom() 和 WSARecvEx()，但它仍然不记录传出数据包!我已经用我的确切代码更新了我的代码。

Answer 1

要有效地使用 Hook ，您需要确保真正 Hook 所有相关端点或至少有一个共同点，确保最终从所有端点调用。
在 recv() 的情况下，我认为应用程序可能实际上调用了 WSARecv()。
您可以使用 depends.exe找出应用程序/库从 Ws2_32.dll 导入的确切功能，以了解您需要挂接哪些功能。