下面我们用代码亲自来实践一个杀毒程序，清除程序的可读可写，并扫描程序的特征码，对病毒进行删除
#include "stdafx.h"
#include "ScanDisk.h"
#include "ScanDiskDlg.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
UINT ThreadProc(LPVOID param){
CScanDiskDlg *ScanDisk=(CScanDiskDlg*)param;
CString part;
int i=0;
int cy=ScanDisk->m_Disk.GetLength()/2;
do{
part=ScanDisk->m_Disk.Mid(2*i,2);
ScanDisk->SearchFolder((char*)part.GetBuffer(0));
i++;
}while(i<cy&&ScanDisk->Status);
char s[256];
sprintf(s,"扫描的文件总数 =%d",ScanDisk->TotalFileNum);
ScanDisk->m_Static.SendMessage(WM_SETTEXT,0,(LPARAM)(LPCTSTR)s);
return 0;
}
/////////////////////////////////////////////////////////////////////////////
// CScanDiskDlg dialog
CScanDiskDlg::CScanDiskDlg(CWnd* pParent /*=NULL*/)
: CDialog(CScanDiskDlg::IDD, pParent)
{
//{{AFX_DATA_INIT(CScanDiskDlg)
m_Disk = _T("");
//}}AFX_DATA_INIT
// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
TotalFileNum=0; //扫描文件总数
}
void CScanDiskDlg::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
//{{AFX_DATA_MAP(CScanDiskDlg)
DDX_Control(pDX, IDC_STATIC1, m_Static);
DDX_Control(pDX, IDC_LIST1, m_List);
DDX_Control(pDX, IDC_Bstart, m_Bstart);
DDX_Text(pDX, IDC_Epartition, m_Disk);
//}}AFX_DATA_MAP
}
BEGIN_MESSAGE_MAP(CScanDiskDlg, CDialog)
//{{AFX_MSG_MAP(CScanDiskDlg)
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_BN_CLICKED(IDC_Bstart, OnBstart)
ON_BN_CLICKED(IDC_Bstop, OnBstop)
ON_EN_CHANGE(IDC_Epartition, OnChangeEpartition)
ON_BN_CLICKED(IDC_Bsave, OnBsave)
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CScanDiskDlg message handlers
BOOL CScanDiskDlg::OnInitDialog()
{
CDialog::OnInitDialog();
// Set the icon for this dialog. The framework does this automatically
// when the application's main window is not a dialog
SetIcon(m_hIcon, TRUE); // Set big icon
SetIcon(m_hIcon, FALSE); // Set small icon
DWORD disk=GetLogicalDrives();
DWORD va=1;
char s[]="A:";
for(int i=0;i<32;i++){
if(disk&(va<<i)){
s[0]=0x41+(char)i;
m_Disk+=s;
}}
UpdateData(FALSE);
Status=FALSE;
return TRUE; // return TRUE unless you set the focus to a control
}
// If you add a minimize button to your dialog, you will need the code below
// to draw the icon. For MFC applications using the document/view model,
// this is automatically done for you by the framework.
void CScanDiskDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this); // device context for painting
SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);
// Center icon in client rectangle
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;
// Draw the icon
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CDialog::OnPaint();
}
}
// The system calls this to obtain the cursor to display while the user drags
// the minimized window.
HCURSOR CScanDiskDlg::OnQueryDragIcon()
{
return (HCURSOR) m_hIcon;
}
void CScanDiskDlg::OnBstart()
{
if(Status==FALSE){
m_List.ResetContent();
TotalFileNum=0;
Status=TRUE;
SubThread=(CWinThread*)AfxBeginThread(&ThreadProc,this,THREAD_PRIORITY_BELOW_NORMAL,0,0);
m_Bstart.SetWindowText("停止");
}
else{
Status=FALSE;
m_Bstart.SetWindowText("开始");
}
}
void CScanDiskDlg::OnBstop()
{
Status=FALSE;
ExitProcess(0);
}
//处理搜索到的可执行文件
BOOL CScanDiskDlg::ProcessFile(char *FileName)
{
CFile file;
CFileStatus rStatus;
CString inf;
DWORD FileLen=0;
BOOL re;
IMAGE_DOS_HEADER dos_header;
IMAGE_NT_HEADERS nt_header;
IMAGE_SECTION_HEADER section_header;
DWORD len;
BYTE *ptr;
//inf=FileName;
//inf.MakeLower();
//if(-1==inf.Find("\\aaa.exe",1))return FALSE;
//m_List.AddString(FileName);
//return FALSE;
re=file.GetStatus(FileName,rStatus); //包含了文件的时间、属性等
if(!re){
// inf="无法操作的文件:";
// inf+=FileName;
// m_List.AddString(inf);
return FALSE;
}
if(rStatus.m_attribute==1){ //只读
re=SetFileAttributes(FileName,rStatus.m_attribute-1);//去掉只读属性
if(re){
inf="无法修改只读属性:";
inf+=FileName;
m_List.AddString(inf);
return FALSE;
}
}
if(file.Open(FileName,CFile::modeReadWrite|CFile::typeBinary)){
FileLen=file.GetLength();
if(FileLen==0)goto endthis_1;//文件长度为0，不处理
len=file.Read(&dos_header,sizeof(IMAGE_DOS_HEADER));
if(dos_header.e_magic==0x5a4d&&len==sizeof(IMAGE_DOS_HEADER)){//含有"MZ"
//判断dos_header.e_lfanew防止偶然
if(dos_header.e_lfanew&&(FileLen>(DWORD)dos_header.e_lfanew+sizeof(IMAGE_NT_HEADERS))){
// m_List.AddString(FileName);
// goto endthis_1;
file.Seek(dos_header.e_lfanew,CFile::begin);
len=file.Read(&nt_header,sizeof(IMAGE_NT_HEADERS));
if(nt_header.Signature==0x4550&&len==sizeof(IMAGE_NT_HEADERS)){ //含有"PE"
//定位到最后一个节
file.Seek(dos_header.e_lfanew+sizeof(IMAGE_NT_HEADERS)+
(nt_header.FileHeader.NumberOfSections-1)*sizeof(IMAGE_SECTION_HEADER),CFile::begin);
len=file.Read(§ion_header,sizeof(section_header));
if((len==sizeof(section_header))&&(!strncmp((char*)section_header.Name,".SD-3",5))){//发现SD-3并处理病毒
// m_List.AddString(FileName);
// goto endthis_1;
BYTE VirusChar[15]={0x55,0x8b,0xec,0x81,0xc4,0xb8, //病毒特征码
0xfe,0xff,0xff,0x60,0xb0,0x2a,0x88,0x45,0xfa};
file.Seek(section_header.PointerToRawData,CFile::begin);
ptr=new BYTE[section_header.Misc.VirtualSize];
file.Read(ptr,section_header.Misc.VirtualSize);
for(int i=0;i<(int)section_header.Misc.VirtualSize-15;i++){
if(!memcmp(ptr+i,VirusChar,15)){ //发现了病毒特征码
file.Seek(section_header.PointerToRawData+i-4,CFile::begin);
DWORD oldEntry;
file.Read(&oldEntry,4); //把特征码上面的jmp oldEntry的原来入口地址值读出
//得到原来入口地址相对虚拟地址
//例如在0x00403059行,有 0xE9A2D8FFFF jmp 1000
//则计算方法为section_header.VirtualAddress+i=0x305E
//0x305E+0xFFFFd8A2=0x1000
//0x305E为指令jmp 1000的下条指令的相对虚拟地址
//修改入口地址
nt_header.OptionalHeader.AddressOfEntryPoint=section_header.VirtualAddress+i+oldEntry;
//得到病毒代码开始区域在文件中的偏移
DWORD strPos=section_header.PointerToRawData+i;
//需要抹去的病毒区域长度
len=file.GetLength()-strPos;
// inf.Format("len=%x,strPos=%x,i=%x--",len,strPos,i);
// m_List.AddString(inf+FileName);
// goto endthis_1;
delete []ptr;
ptr=new BYTE[len];
//清0
memset(ptr,0,len);
file.Seek(strPos,CFile::begin);
file.Write(ptr,len);//覆盖病毒区域
file.Seek(dos_header.e_lfanew,CFile::begin);
strcpy((char*)section_header.Name,".kill"); //修改节名
//修改PE头（包含有入口地址）
file.Write(&nt_header,sizeof(nt_header));
//定位到最后一个节表位置，修改
file.Seek(dos_header.e_lfanew+sizeof(nt_header)+(nt_header.FileHeader.NumberOfSections-1)*
sizeof(section_header),CFile::begin);
file.Write(§ion_header,sizeof(section_header));
delete []ptr;
inf="发现SD-3,清除:";
inf+=FileName;
m_List.AddString(inf+FileName);
break;
}
}
}
}
}
}
endthis_1:
file.Close();
file.SetStatus(FileName,rStatus);
}
/*
else{ //不能打开文件，则只读方式打开。只分析有无病毒
if(!file.Open(FileName,CFile::modeRead|CFile::typeBinary)){
inf="不能修改:";
inf+=FileName;
m_List.AddString(inf);
}
FileLen=file.GetLength();
if(FileLen==0)goto endthis_2;//文件长度为0，不处理
len=file.Read(&dos_header,sizeof(IMAGE_DOS_HEADER));
if(dos_header.e_magic==0x5a4d&&len==sizeof(IMAGE_DOS_HEADER)){//含有"MZ"
//考虑到后面的dos_header.e_lfanew-1,必要
if(dos_header.e_lfanew&&FileLen>(DWORD)dos_header.e_lfanew){
file.Seek(dos_header.e_lfanew,CFile::begin);
len=file.Read(&nt_header,sizeof(IMAGE_NT_HEADERS));
if(nt_header.Signature==0x4550&&len==sizeof(IMAGE_NT_HEADERS)){ //含有"PE"
file.Seek(dos_header.e_lfanew+sizeof(IMAGE_NT_HEADERS)+
(nt_header.FileHeader.NumberOfSections-1)*sizeof(IMAGE_SECTION_HEADER),CFile::begin);
file.Read(§ion_header,sizeof(section_header));
if(!strncmp((char*)section_header.Name,".SD-3",5)){//发现SD-3病毒
BYTE VirusChar[15]={0x55,0x8b,0xec,0x81,0xc4,0xb8, //病毒特征码
0xfe,0xff,0xff,0x60,0xb0,0x2a,0x88,0x45,0xfa};
file.Seek(section_header.PointerToRawData,CFile::begin);
ptr=new BYTE[section_header.Misc.VirtualSize];
file.Read(ptr,section_header.Misc.VirtualSize);
for(int i=0;i<(int)section_header.Misc.VirtualSize-15;i++){
if(!memcmp(ptr+i,VirusChar,15)){ //发现了病毒特征码
inf="无法清除的SD-3病毒:";
inf+=FileName;
m_List.AddString(inf);
}}}
}}}
endthis_2:
file.Close();
file.SetStatus(FileName,rStatus);
}
*/
return TRUE;
}
//搜索其下所有子目录及文件.
void CScanDiskDlg::SearchFolder(char *path)
{
HANDLE h;
WIN32_FIND_DATA dat;
BOOL re;
char dir[300];
strcpy(dir,path);
strcat(dir,"\\*.*");
h=FindFirstFile(dir,&dat);
if(h==INVALID_HANDLE_VALUE){
//AfxMessageBox(dir);
return;
}
char FullName[300];
do{
re=FindNextFile(h,&dat);
if(!re)break;
if(!strncmp(dat.cFileName,"..",2))continue;
if(!(FILE_ATTRIBUTE_DIRECTORY&dat.dwFileAttributes)){ //不是目录
strcpy(FullName,path);
strcat(FullName,"\\\0");
strcat(FullName,dat.cFileName);
//CString exe=dat.cFileName;
//exe.MakeLower();
//if(-1!=exe.Find(".exe",2))m_List.AddString(FullName);
m_Static.SendMessage(WM_SETTEXT,0,(LPARAM)(LPCTSTR)FullName);
ProcessFile(FullName);
TotalFileNum++;
}
else { //是目录，进入子目录
char next[300];
strcpy(next,path);
strcat(next,"\\\0");
strcat(next,dat.cFileName);
//m_List.AddString(next);
SearchFolder(next);
}
}while(Status);
FindClose(h);
}
void CScanDiskDlg::OnChangeEpartition()
{
UpdateData();
}
void CScanDiskDlg::OnBsave()
{
AfxMessageBox("结果保存在c:\\inf.txt");
CFile fp;
fp.Open("c:\\inf.txt",CFile::modeCreate|CFile.modeWrite);
if(!fp)return;
int col=m_List.GetCount();
if(col==LB_ERR){ fp.Close(); return; }
char s[400];
for(int i=0;i<col;i++){
memset(s,0,400);
m_List.GetText(i,s);
strcat(s,"\r\n");
fp.Write(s,strlen(s));
}
fp.Close();
}