COM组件开发实践（三）

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phinecos 2021-08-05 14:32:21 博主文章分类：C/C++/VC++ ©著作权

文章标签 控件 #include 数字签名 3c 新版本 文章分类 Java 后端开发

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前面两篇文章分别介绍了MFC ActiveX应用程序和使用ATL开发ActiveX的简单实例，但还有两个问题需要解决：

1）标记ActiveX控件为安全的控件 2)对控件进行数字签名。本文将结合这两点进行简单的介绍。

Building a Safe ActiveX Control

如何不想办法将控件标记为安全的，就会在Web页面与控件进行交互时出现如下图的警告信息：

COM组件开发实践（三）_新版本

下面将分别介绍在MFC ActiveX和ATL中如何标记一个控件为安全的控件。

要标记一个MFC ActiveX控件为安全，可以仿照下面代码修改而得：

// CardScan.cpp : CCardScanApp 和DLL 注册的实现。
#include "stdafx.h"
#include "CardScan.h"
#include "comcat.h"
#include "strsafe.h"
#include "objsafe.h"

CCardScanApp theApp;
const GUID CDECL BASED_CODE _tlid =
        { 0x29959268, 0x9729, 0x458E, { 0xA8, 0x39, 0xBB, 0x39, 0x2E, 0xCB, 0x7E, 0x37 } };
const WORD _wVerMajor = 1;
const WORD _wVerMinor = 0;
const CATID CLSID_SafeItem =
{0xB548F3C7,0x2135,0x4242,{0x92,0x0B,0xA7,0xBD,0xEE,0x6D,0x2B,0xA3}};

//{ 0x36299202, 0x9ef, 0x4abf,{ 0xad, 0xb9, 0x47, 0xc5, 0x99, 0xdb, 0xe7, 0x78}};
// CCardScanApp::InitInstance - DLL 初始化
BOOL CCardScanApp::InitInstance()
{
    BOOL bInit = COleControlModule::InitInstance();
    if (bInit)
    {
    }
    return bInit;
}
// CCardScanApp::ExitInstance - DLL 终止
int CCardScanApp::ExitInstance()
{
    return COleControlModule::ExitInstance();
}
HRESULT CreateComponentCategory(CATID catid, CHAR *catDescription)
{
    ICatRegister *pcr = NULL ;
    HRESULT hr = S_OK ;
    hr = CoCreateInstance(CLSID_StdComponentCategoriesMgr,
        NULL, CLSCTX_INPROC_SERVER, IID_ICatRegister, (void**)&pcr);
    if (FAILED(hr))
        return hr;
    // Make sure the HKCR\Component Categories\{..catid COM组件开发实践（三）_控件_02

}
    // key is registered.
    CATEGORYINFO catinfo;
    catinfo.catid = catid;
    catinfo.lcid = 0x0409 ; // english
    size_t len;
    // Make sure the provided description is not too long.
    // Only copy the first 127 characters if it is.
    // The second parameter of StringCchLength is the maximum
    // number of characters that may be read into catDescription.
    // There must be room for a NULL-terminator. The third parameter
    // contains the number of characters excluding the NULL-terminator.
    hr = StringCchLength(catDescription, STRSAFE_MAX_CCH, &len);
    if (SUCCEEDED(hr))
    {
        if (len>127)
        {
            len = 127;
        }
    }
    else
    {
        // TODO: Write an error handler;
    }
    // The second parameter of StringCchCopy is 128 because you need
    // room for a NULL-terminator.
    hr = StringCchCopy(COLE2T(catinfo.szDescription), len + 1, catDescription);
    // Make sure the description is null terminated.
    catinfo.szDescription[len + 1] = '\0';
    hr = pcr->RegisterCategories(1, &catinfo);
    pcr->Release();
    return hr;
}
// HRESULT RegisterCLSIDInCategory -
//      Register your component categories information
HRESULT RegisterCLSIDInCategory(REFCLSID clsid, CATID catid)
{
    // Register your component categories information.
    ICatRegister *pcr = NULL ;
    HRESULT hr = S_OK ;
    hr = CoCreateInstance(CLSID_StdComponentCategoriesMgr,
        NULL, CLSCTX_INPROC_SERVER, IID_ICatRegister, (void**)&pcr);
    if (SUCCEEDED(hr))
    {
        // Register this category as being "implemented" by the class.
        CATID rgcatid[1] ;
        rgcatid[0] = catid;
        hr = pcr->RegisterClassImplCategories(clsid, 1, rgcatid);
    }
    if (pcr != NULL)
        pcr->Release();
    return hr;
}

// HRESULT UnRegisterCLSIDInCategory - Remove entries from the registry
HRESULT UnRegisterCLSIDInCategory(REFCLSID clsid, CATID catid)
{
    ICatRegister *pcr = NULL ;
    HRESULT hr = S_OK ;
    hr = CoCreateInstance(CLSID_StdComponentCategoriesMgr,
        NULL, CLSCTX_INPROC_SERVER, IID_ICatRegister, (void**)&pcr);
    if (SUCCEEDED(hr))
    {
        // Unregister this category as being "implemented" by the class.
        CATID rgcatid[1] ;
        rgcatid[0] = catid;
        hr = pcr->UnRegisterClassImplCategories(clsid, 1, rgcatid);
    }
    if (pcr != NULL)
        pcr->Release();
    return hr;
}
// DllRegisterServer - 将项添加到系统注册表

STDAPI DllRegisterServer(void)
{
    HRESULT hr;
    AFX_MANAGE_STATE(_afxModuleAddrThis);
    if (!AfxOleRegisterTypeLib(AfxGetInstanceHandle(), _tlid))
        return ResultFromScode(SELFREG_E_TYPELIB);
    if (!COleObjectFactoryEx::UpdateRegistryAll(TRUE))
        return ResultFromScode(SELFREG_E_CLASS);
    // Mark the control as safe for initializing.
    hr = CreateComponentCategory(CATID_SafeForInitializing,
        _T("Controls safely initializable from persistent data!"));
    if (FAILED(hr))
        return hr;
    hr = RegisterCLSIDInCategory(CLSID_SafeItem,
        CATID_SafeForInitializing);
    if (FAILED(hr))
        return hr;
    // Mark the control as safe for scripting.
    hr = CreateComponentCategory(CATID_SafeForScripting,
        _T("Controls safely  scriptable!"));
    if (FAILED(hr))
        return hr;
    hr = RegisterCLSIDInCategory(CLSID_SafeItem,
        CATID_SafeForScripting);
    if (FAILED(hr))
        return hr;
    return NOERROR;
}

// DllUnregisterServer - 将项从系统注册表中移除

STDAPI DllUnregisterServer(void)
{
    HRESULT hr;
    AFX_MANAGE_STATE(_afxModuleAddrThis);
    // Remove entries from the registry.
    hr=UnRegisterCLSIDInCategory(CLSID_SafeItem,
        CATID_SafeForInitializing);
    if (FAILED(hr))
        return hr;
    hr=UnRegisterCLSIDInCategory(CLSID_SafeItem,
        CATID_SafeForScripting);
    if (FAILED(hr))
        return hr;
    if (!AfxOleUnregisterTypeLib(_tlid, _wVerMajor, _wVerMinor))
        return ResultFromScode(SELFREG_E_TYPELIB);
    if (!COleObjectFactoryEx::UpdateRegistryAll(FALSE))
        return ResultFromScode(SELFREG_E_CLASS);
    return NOERROR;
}

这里值得注意的一个地方是DllUnregisterServer函数，在这段代码中，我是将

hr=UnRegisterCLSIDInCategory(CLSID_SafeItem, CATID_SafeForInitializing);

hr=UnRegisterCLSIDInCategory(CLSID_SafeItem, CATID_SafeForScripting);

这两句代码放在

if (!AfxOleUnregisterTypeLib(_tlid, _wVerMajor, _wVerMinor))

           return ResultFromScode(SELFREG_E_TYPELIB);

      if (!COleObjectFactoryEx::UpdateRegistryAll(FALSE))

           return ResultFromScode(SELFREG_E_CLASS);

这两句代码的前面，如果你查阅MSDN，将会发现它上面的顺序和我是相反的，这应该是微软的一个错误代码，如果按照MSDN的代码来写，则你使用regsvr32 -u CardScan.ocx反注册时会报下面的错误：

COM组件开发实践（三）_3c_03

调整为我所说的顺序就没问题了。

2）要标记使用ATL写的ActiveX控件为安全的控件，这比MFC要简单的多，只需要在控件头文件中增加几行代码就可以了：

class ATL_NO_VTABLE CTestCtrl :
…
public IObjectSafetyImpl<CTestCtrl, INTERFACESAFE_FOR_UNTRUSTED_CALLER| INTERFACESAFE_FOR_UNTRUSTED_DATA>,

然后在COM映射表中增加一项：

BEGIN_COM_MAP(CTestCtrl)
…
COM_INTERFACE_ENTRY(IObjectSafety)
END_COM_MAP()

Building a Signed ActiveX Control

ActiveX控件是个危险的东西，如果不对其合法性进行数字签名和验证，IE是会拒绝其安装的。

工具包准备：CABARC.exe, cert2spc.exe, makecab.exe, makecert.exe, signcode.exe(或新版本中的signtool)，以上小工具都可以在VS的安装路径下"Common7"Tools"Bin找到，或去微软官方网站上下载。

ActiveX控件的安装过程中，一部分工作就是自注册，这需要控件在VERSIONINFO结构中定义OLESelfRegister值，你可以对资源文件进行编辑如下

BEGIN
    BLOCK "StringFileInfo"
    BEGIN
        BLOCK "080403a8"
        BEGIN
            VALUE "CompanyName", "TODO: <公司名>"
            VALUE "FileDescription", "TODO: <文件说明>"
            VALUE "FileVersion", "1.0.0.1"
            VALUE "InternalName", "CardScan.ocx"
            VALUE "LegalCopyright", "TODO: (C) <公司名>。保留所有权利。"
            VALUE "OLESelfRegister", "\0"
            VALUE "OriginalFilename", "CardScan.ocx"
            VALUE "ProductName", "TODO: <产品名>"
            VALUE "ProductVersion", "1.0.0.1"
        END
    END
    BLOCK "VarFileInfo"
    BEGIN
        VALUE "Translation", 0x804, 936
    END
END

打包为CAB文件

因为ActiveX控件要放在网站上供客户下载到本地，因此压缩是必需的。一段典型的html代码如下：

CODEBASE就指明了要下载的压缩包，其中包含了oxc，dll控件等所需要的文件。

通常CAB文件包含了一个INF文件，它用来描述CAB文件的所有细节信息，下面举个简单例子，代码如下：

; Sample INF file for SCRIPTABLEACTIVEX.DLL
[version]
; version signature (same for both NT and Win95) do not remove
signature="$CHICAGO$"
AdvancedINF=2.0

[Add.Code]
CardScan.ocx=CardScan.ocx
CardScan.inf=CardScan.inf

[CardScan.ocx]
file-win32-x86=thiscab
clsid={B548F3C7-2135-4242-920B-A7BDEE6D2BA3}
FileVersion=1,0,0,1
RegisterServer=yes

[CardScan.inf]
file=thiscab
; end of INF file