WeChatFerry/spy/receive_msg.cpp

#pragma execution_character_set("utf-8")

#include "framework.h"
#include <condition_variable>
#include <mutex>
#include <queue>

#include "load_calls.h"
#include "receive_msg.h"
#include "util.h"

// Defined in rpc_server.cpp
extern bool gIsListening;
extern mutex gMutex;
extern condition_variable gCV;
extern queue<WxMsg_t> gMsgQueue;

// Defined in spy.cpp
extern WxCalls_t g_WxCalls;
extern DWORD g_WeChatWinDllAddr;

static DWORD reg_buffer          = 0;
static DWORD recvMsgHookAddr     = 0;
static DWORD recvMsgCallAddr     = 0;
static DWORD recvMsgJumpBackAddr = 0;
static CHAR recvMsgBackupCode[5] = { 0 };

MsgTypes_t GetMsgTypes()
{
    const MsgTypes_t m = { { 0x01, "文字" },
                           { 0x03, "图片" },
                           { 0x22, "语音" },
                           { 0x25, "好友确认" },
                           { 0x28, "POSSIBLEFRIEND_MSG" },
                           { 0x2A, "名片" },
                           { 0x2B, "视频" },
                           { 0x2F, "石头剪刀布 | 表情图片" },
                           { 0x30, "位置" },
                           { 0x31, "共享实时位置、文件、转账、链接" },
                           { 0x32, "VOIPMSG" },
                           { 0x33, "微信初始化" },
                           { 0x34, "VOIPNOTIFY" },
                           { 0x35, "VOIPINVITE" },
                           { 0x3E, "小视频" },
                           { 0x270F, "SYSNOTICE" },
                           { 0x2710, "红包、系统消息" },
                           { 0x2712, "撤回消息" } };

    return m;
}

void HookAddress(DWORD hookAddr, LPVOID funcAddr, CHAR recvMsgBackupCode[5])
{
    // 组装跳转数据
    BYTE jmpCode[5] = { 0 };
    jmpCode[0]      = 0xE9;

    // 计算偏移
    *(DWORD *)&jmpCode[1] = (DWORD)funcAddr - hookAddr - 5;

    // 备份原来的代码
    ReadProcessMemory(GetCurrentProcess(), (LPVOID)hookAddr, recvMsgBackupCode, 5, 0);
    // 写入新的代码
    WriteProcessMemory(GetCurrentProcess(), (LPVOID)hookAddr, jmpCode, 5, 0);
}

void UnHookAddress(DWORD hookAddr, CHAR restoreCode[5])
{
    WriteProcessMemory(GetCurrentProcess(), (LPVOID)hookAddr, restoreCode, 5, 0);
}

void DispatchMsg(DWORD reg)
{
    WxMsg_t wxMsg;
    DWORD *p = (DWORD *)reg; // 消息结构基址

    wxMsg.type    = GET_DWORD(*p + g_WxCalls.recvMsg.type);
    wxMsg.is_self = GET_DWORD(*p + g_WxCalls.recvMsg.isSelf);
    wxMsg.id      = GetStringByAddress(*p + g_WxCalls.recvMsg.msgId);
    wxMsg.xml     = GetStringByAddress(*p + g_WxCalls.recvMsg.msgXml);

    // 群里的系统消息，xml 为空；或者包含 <membercount>
    if ((wxMsg.xml.empty()) || (wxMsg.xml.find("<membercount>") != string::npos)) {
        wxMsg.is_group = true;
        wxMsg.sender   = GetStringByAddress(*p + g_WxCalls.recvMsg.wxId);
        wxMsg.roomid   = GetStringByAddress(*p + g_WxCalls.recvMsg.roomId);
    } else {
        wxMsg.is_group = false;
        wxMsg.sender   = GetStringByAddress(*p + g_WxCalls.recvMsg.roomId);
    }
    wxMsg.content = GetStringByAddress(*p + g_WxCalls.recvMsg.content);

    {
        unique_lock<mutex> lock(gMutex);
        gMsgQueue.push(wxMsg); // 推送到队列
    }

    gCV.notify_all(); // 通知各方消息就绪
}

__declspec(naked) void RecieveMsgFunc()
{
    __asm {
        mov reg_buffer, edi // 把值复制出来
    }

    DispatchMsg(reg_buffer);

    __asm
    {
        call recvMsgCallAddr // 这个为被覆盖的call
        jmp recvMsgJumpBackAddr // 跳回被HOOK指令的下一条指令
    }
}

void ListenMessage()
{
    // OutputDebugString(L"ListenMessage\n");
    // MessageBox(NULL, L"ListenMessage", L"ListenMessage", 0);
    if (gIsListening || (g_WeChatWinDllAddr == 0)) {
        return;
    }

    recvMsgHookAddr     = g_WeChatWinDllAddr + g_WxCalls.recvMsg.hook;
    recvMsgCallAddr     = g_WeChatWinDllAddr + g_WxCalls.recvMsg.call;
    recvMsgJumpBackAddr = recvMsgHookAddr + 5;

    HookAddress(recvMsgHookAddr, RecieveMsgFunc, recvMsgBackupCode);
    gIsListening = true;
}

void UnListenMessage()
{
    if (!gIsListening) {
        return;
    }
    UnHookAddress(recvMsgHookAddr, recvMsgBackupCode);
    gIsListening = false;
}