Question

我正在为Windows实现进程提升助手。这是一个将以提升模式运行并使用管理员权限启动其他程序而不显示其他UAC提示的程序。出于安全原因，我想确保只能使用我公司的Authenticode密钥进行数字签名的二进制文件。

WinVerifyTrust函数让我到了中途，但它只能确保二进制文件由某些密钥签名，该密钥是Microsoft信任链的一部分。是否有一种相对简单的方法来执行Authenticode验证并确保它由我们的私钥签名？

Answer 1

我相信你所寻找的是CryptQueryObject。

有了它，您应该可以从PE中提取相关证书，并进行任何其他检查。

举例来说，这将使您获得HCRYPTMSG。从那里你可以使用CryptMsgGetParam拉出你想要的任何东西。我希望能做出更“强大”的东西，但这些API非常多毛，因为它们需要大量的分支才能处理所有返回的情况。

所以，这是一个p / invoke-rific c＃示例（我从C开始，但这基本上是不可读的）：

static class Crypt32
{
    //Omitting flag constants; you can look these up in WinCrypt.h

    [DllImport("CRYPT32.DLL", EntryPoint = "CryptQueryObject", CharSet = CharSet.Auto, SetLastError = true)]
    public static extern bool CryptQueryObject(
        int dwObjectType,
        IntPtr pvObject,
        int dwExpectedContentTypeFlags,
        int dwExpectedFormatTypeFlags,
        int dwFlags,
        out int pdwMsgAndCertEncodingType,
        out int pdwContentType,
        out int pdwFormatType,
        ref IntPtr phCertStore,
        ref IntPtr phMsg,
        ref IntPtr ppvContext);
}

class Program
{
    static void Main(string[] args)
    {
        //Path to executable here
        //  I tested with MS-Office .exe's
        string path = "";

        int contentType;
        int formatType;
        int ignored;
        IntPtr context = IntPtr.Zero;
        IntPtr pIgnored = IntPtr.Zero;

        IntPtr cryptMsg = IntPtr.Zero;

        if (!Crypt32.CryptQueryObject(
            Crypt32.CERT_QUERY_OBJECT_FILE,
            Marshal.StringToHGlobalUni(path),
            Crypt32.CERT_QUERY_CONTENT_FLAG_ALL,
            Crypt32.CERT_QUERY_FORMAT_FLAG_ALL,
            0,
            out ignored,
            out contentType,
            out formatType,
            ref pIgnored,
            ref cryptMsg,
            ref context))
        {
            int error = Marshal.GetLastWin32Error();

            Console.WriteLine((new Win32Exception(error)).Message);

            return;
        }

        //expecting '10'; CERT_QUERY_CONTENT_PKCS7_SIGNED_EMBED
        Console.WriteLine("Context Type: " + contentType);

        //Which implies this is set
        Console.WriteLine("Crypt Msg: " + cryptMsg.ToInt32());

        return;
    }

Answer 2

要从签名代码中获取证书信息，请使用以下命令：

using System.Security.Cryptography.X509Certificates;
X509Certificate basicSigner = X509Certificate.CreateFromSignedFile(filename);
X509Certificate2 cert = new X509Certificate2(basicSigner);

然后您可以获得这样的证书详细信息：

Console.WriteLine(cert.IssuerName.Name);
Console.WriteLine(cert.SubjectName.Name);
// etc

Answer 3

这些是我曾经使用过的最糟糕的API

警告：它比你想象的要糟糕。

至少自从引入SHA-256签名以来（这种情况一直如此？），Authenticode可能有多个签名。它们未在PKCS-7签名消息中编码为多个签名;相反，它们是OID_NESTED_SIGNATURE类型的未经身份验证的消息属性，每个属性包含另一个完整的PKCS-7签名消息。

如果任何签名有效并且来自可信证书链，WinVerifyTrust会告诉您该文件是有效的。但是它不会告诉你哪些签名是有效的。如果您随后使用CryptQueryObject读取完整的PKCS-7消息，并且只查看主要签名的证书（如此处和MSDN上的代码示例），则您不一定要查看已验证的证书。关联的签名可能与可执行文件不匹配，和/或证书可能没有可信CA链。

如果您使用主要签名的详细信息来验证证书是您的软件信任的证书，那么您很容易受到WinVerifyTrust信任辅助签名的情况的影响，但您的代码正在检查主要签名证书是您所期望的，并且您没有注意到主证书的签名是无意义的。攻击者可以在不拥有私钥的情况下使用您的公共证书，并结合发给其他人的其他代码签名证书，以此方式绕过发布者检查。

从Win8开始，WinVerifyTrust可以选择性地验证特定签名，因此您应该能够迭代签名以找到符合您要求的和的签名。

如果你必须与Win7兼容，据我所知，你可以管理的最好的是MsiGetFileSignatureInformation。从实验（对于其他所有内容，实际的文档令人沮丧），它似乎在WinVerifyTrust信任一个时返回可信证书。但是，如果没有可信任的签名，它仍然会返回主要签名证书，因此您仍然必须首先使用WinVerifyTrust来检查。

当然，这里还有很多可能的检查时间/使用时间问题。

Answer 4

在这里找到了解决方案：

http://www.ucosoft.com/how-to-program-to-retrieve-the-authenticode-information.html

这里有缩进：

#define _UNICODE 1
#define UNICODE 1

#include <windows.h>
#include <tchar.h>
#include <wincrypt.h>
#include <Softpub.h>
#include <stdio.h>
#include <stdlib.h>

#pragma comment (lib, "Crypt32")

// the Authenticode Signature is encode in PKCS7
#define ENCODING (X509_ASN_ENCODING | PKCS_7_ASN_ENCODING)

// Information structure of authenticode sign
typedef struct 
{
    LPWSTR lpszProgramName; 
    LPWSTR lpszPublisherLink;
    LPWSTR lpszMoreInfoLink;

    DWORD cbSerialSize;
    LPBYTE lpSerialNumber;
    LPTSTR lpszIssuerName;
    LPTSTR lpszSubjectName;
} 
SPROG_SIGNATUREINFO, *PSPROG_SIGNATUREINFO;

VOID GetProgAndPublisherInfo(PCMSG_SIGNER_INFO pSignerInfo, PSPROG_SIGNATUREINFO pInfo);
VOID GetCertificateInfo(HCERTSTORE hStore, PCMSG_SIGNER_INFO pSignerInfo, PSPROG_SIGNATUREINFO pInfo);

BOOL GetAuthenticodeInformation(LPCTSTR lpszFileName, PSPROG_SIGNATUREINFO pInfo)
{
    HCERTSTORE hStore = NULL;
    HCRYPTMSG hMsg = NULL;
    PCMSG_SIGNER_INFO pSignerInfo = NULL;
    DWORD dwSignerInfo;

    BOOL bRet = FALSE;

    __try
    {
        // as CryptQueryObject() only accept WCHAR file name, convert first
        WCHAR wszFileName[MAX_PATH];
#ifdef UNICODE
        if ( !lstrcpynW( wszFileName, lpszFileName, MAX_PATH))
            __leave;
#else
        if ( mbstowcs( wszFileName, lpszFileName, MAX_PATH) == -1)
            __leave;
#endif
        //Retrieve the Message Handle and Store Handle
        DWORD dwEncoding, dwContentType, dwFormatType;
        if ( !CryptQueryObject( CERT_QUERY_OBJECT_FILE, wszFileName,
                                CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED,
                                CERT_QUERY_FORMAT_FLAG_BINARY, 0, &dwEncoding,
                                &dwContentType, &dwFormatType, &hStore,
                                &hMsg, NULL))
            __leave;

        //Get the length of SignerInfo
        if ( !CryptMsgGetParam( hMsg, CMSG_SIGNER_INFO_PARAM, 0, NULL, &dwSignerInfo))
            __leave;

        // allocate the memory for SignerInfo
        if ( !(pSignerInfo = (PCMSG_SIGNER_INFO)LocalAlloc( LPTR, dwSignerInfo)))
            __leave;

        // get the SignerInfo
        if ( !CryptMsgGetParam( hMsg, CMSG_SIGNER_INFO_PARAM, 0, (PVOID)pSignerInfo, &dwSignerInfo))
            __leave;

        //get the Publisher from SignerInfo
        GetProgAndPublisherInfo( pSignerInfo, pInfo);

        //get the Certificate from SignerInfo
        GetCertificateInfo( hStore, pSignerInfo, pInfo);

        bRet = TRUE;
    }
    __finally
    {
        // release the memory
        if (pSignerInfo != NULL) LocalFree(pSignerInfo);
        if (hStore != NULL) CertCloseStore(hStore, 0);
        if (hMsg != NULL) CryptMsgClose(hMsg);
    }
    return bRet;
}


LPWSTR AllocateAndCopyWideString(LPCWSTR inputString)
{
    LPWSTR outputString = NULL;

    // allocate the memory
    outputString = (LPWSTR)VirtualAlloc(NULL, (wcslen(inputString) + 1) * sizeof(TCHAR), MEM_COMMIT, PAGE_READWRITE);

    // copy
    if (outputString != NULL)
    {
        lstrcpyW(outputString, inputString);
    }

    return outputString;
}


VOID GetProgAndPublisherInfo(PCMSG_SIGNER_INFO pSignerInfo, PSPROG_SIGNATUREINFO pInfo)
{
    PSPC_SP_OPUS_INFO OpusInfo = NULL;
    DWORD dwData;

    __try
    {
        // query SPC_SP_OPUS_INFO_OBJID OID in Authenticated Attributes
        for (DWORD n = 0; n < pSignerInfo->AuthAttrs.cAttr; n++)
        {
            if (lstrcmpA(SPC_SP_OPUS_INFO_OBJID, pSignerInfo->AuthAttrs.rgAttr[n].pszObjId) == 0)
            {
                // get the length of SPC_SP_OPUS_INFO
                if ( !CryptDecodeObject(ENCODING,
                                        SPC_SP_OPUS_INFO_OBJID,
                                        pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].pbData,
                                        pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].cbData,
                                        0,
                                        NULL,
                                        &dwData))
                    __leave;

                // allocate the memory for SPC_SP_OPUS_INFO
                if ( !(OpusInfo = (PSPC_SP_OPUS_INFO)LocalAlloc(LPTR, dwData)))
                    __leave;

                // get SPC_SP_OPUS_INFO structure
                if ( !CryptDecodeObject(ENCODING,
                                        SPC_SP_OPUS_INFO_OBJID,
                                        pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].pbData,
                                        pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].cbData,
                                        0,
                                        OpusInfo,
                                        &dwData))
                    __leave;

                // copy the Program Name of SPC_SP_OPUS_INFO to the return variable
                if (OpusInfo->pwszProgramName)
                {
                    pInfo->lpszProgramName = AllocateAndCopyWideString(OpusInfo->pwszProgramName);
                }
                else
                    pInfo->lpszProgramName = NULL;

                // copy the Publisher Info of SPC_SP_OPUS_INFO to the return variable
                if (OpusInfo->pPublisherInfo)
                {
                    switch (OpusInfo->pPublisherInfo->dwLinkChoice)
                    {
                        case SPC_URL_LINK_CHOICE:
                            pInfo->lpszPublisherLink = AllocateAndCopyWideString(OpusInfo->pPublisherInfo->pwszUrl);
                            break;

                        case SPC_FILE_LINK_CHOICE:
                            pInfo->lpszPublisherLink = AllocateAndCopyWideString(OpusInfo->pPublisherInfo->pwszFile);
                            break;

                        default:
                            pInfo->lpszPublisherLink = NULL;
                            break;
                    }
                }
                else
                {
                    pInfo->lpszPublisherLink = NULL;
                }

                // copy the More Info of SPC_SP_OPUS_INFO to the return variable
                if (OpusInfo->pMoreInfo)
                {
                    switch (OpusInfo->pMoreInfo->dwLinkChoice)
                    {
                        case SPC_URL_LINK_CHOICE:
                            pInfo->lpszMoreInfoLink = AllocateAndCopyWideString(OpusInfo->pMoreInfo->pwszUrl);
                            break;

                        case SPC_FILE_LINK_CHOICE:
                            pInfo->lpszMoreInfoLink = AllocateAndCopyWideString(OpusInfo->pMoreInfo->pwszFile);
                            break;

                        default:
                            pInfo->lpszMoreInfoLink = NULL;
                            break;
                    }
                }
                else
                {
                    pInfo->lpszMoreInfoLink = NULL;
                }

                break; // we have got the information, break
            }
        }
    }
    __finally
    {
        if (OpusInfo != NULL) LocalFree(OpusInfo);
    }
}


VOID GetCertificateInfo(HCERTSTORE hStore, PCMSG_SIGNER_INFO pSignerInfo, PSPROG_SIGNATUREINFO pInfo)
{
    PCCERT_CONTEXT pCertContext = NULL;

    __try
    {
        CERT_INFO CertInfo;
        DWORD dwData;

        // query Signer Certificate in Certificate Store
        CertInfo.Issuer = pSignerInfo->Issuer;
        CertInfo.SerialNumber = pSignerInfo->SerialNumber;

        if ( !(pCertContext = CertFindCertificateInStore(   hStore,
                                                            ENCODING, 0, CERT_FIND_SUBJECT_CERT,
                                                            (PVOID)&CertInfo, NULL)))
            __leave;

        dwData = pCertContext->pCertInfo->SerialNumber.cbData;

        // SPROG_SIGNATUREINFO.cbSerialSize
        pInfo->cbSerialSize = dwData;

        // SPROG_SIGNATUREINFO.lpSerialNumber
        pInfo->lpSerialNumber = (LPBYTE)VirtualAlloc(NULL, dwData, MEM_COMMIT, PAGE_READWRITE);
        memcpy( pInfo->lpSerialNumber, pCertContext->pCertInfo->SerialNumber.pbData, dwData);

        // SPROG_SIGNATUREINFO.lpszIssuerName
        __try
        {
            // get the length of Issuer Name
            if (!(dwData = CertGetNameString(   pCertContext,
                                                CERT_NAME_SIMPLE_DISPLAY_TYPE,
                                                CERT_NAME_ISSUER_FLAG, NULL, NULL, 0)))
                __leave;

            // allocate the memory
            if ( !(pInfo->lpszIssuerName = (LPTSTR)VirtualAlloc(NULL, dwData * sizeof(TCHAR), MEM_COMMIT, PAGE_READWRITE)))
                __leave;

            // get Issuer Name
            if (!(CertGetNameString(pCertContext,
                                    CERT_NAME_SIMPLE_DISPLAY_TYPE,
                                    CERT_NAME_ISSUER_FLAG, NULL, pInfo->
                                    lpszIssuerName, dwData)))
                __leave;
        }
        __finally
        {
        }

        // SPROG_SIGNATUREINFO.lpszSubjectName
        __try
        {
            //get the length of Subject Name
            if (!(dwData = CertGetNameString( pCertContext, CERT_NAME_SIMPLE_DISPLAY_TYPE, 0, NULL, NULL, 0)))
                __leave;

            // allocate the memory
            if ( !(pInfo->lpszSubjectName = (LPTSTR)VirtualAlloc(NULL, dwData * sizeof(TCHAR), MEM_COMMIT, PAGE_READWRITE)))
                __leave;

            // get Subject Name
            if (!(CertGetNameString( pCertContext, CERT_NAME_SIMPLE_DISPLAY_TYPE, 0, NULL, pInfo->lpszSubjectName, dwData)))
                __leave;
        }
        __finally
        {
        }
    }
    __finally
    {
        if (pCertContext != NULL)
            CertFreeCertificateContext(pCertContext);
    }
}


int _tmain(int argc, TCHAR *argv[])
{
    if (argc != 2)
    {
        _tprintf(_T("Usage: SignedFileInfo \n"));
        return 0;
    }
    else
    {
        SPROG_SIGNATUREINFO SignInfo;

        ZeroMemory(&SignInfo, sizeof(SignInfo));

        GetAuthenticodeInformation( argv[1], &SignInfo);

        wprintf(L"Program Name: %s\n", SignInfo.lpszProgramName);
        wprintf(L"Publisher Link: %s\n", SignInfo.lpszPublisherLink);
        wprintf(L"More Info Link: %s\n", SignInfo.lpszMoreInfoLink);

        {
            _tprintf(_T("Serial Number: "));
            DWORD dwData = SignInfo.cbSerialSize;
            for (DWORD n = 0; n < dwData; n++)
            {
                _tprintf(_T("%02x "),
                    SignInfo.lpSerialNumber[dwData - (n + 1)]);
            }
            _tprintf(_T("\n"));
        }
        _tprintf(_T("Issuer Name: %s\n"), SignInfo.lpszIssuerName);
        _tprintf(_T("Subject Name: %s\n"), SignInfo.lpszSubjectName);
        if ( SignInfo.lpszProgramName) VirtualFree(SignInfo.lpszProgramName, 0, MEM_RELEASE);
        if ( SignInfo.lpszPublisherLink) VirtualFree(SignInfo.lpszPublisherLink, 0, MEM_RELEASE);
        if ( SignInfo.lpszMoreInfoLink) VirtualFree(SignInfo.lpszMoreInfoLink, 0, MEM_RELEASE);
        if ( SignInfo.lpSerialNumber) VirtualFree(SignInfo.lpSerialNumber, 0, MEM_RELEASE);
        if ( SignInfo.lpszIssuerName) VirtualFree(SignInfo.lpszIssuerName, 0, MEM_RELEASE);
        if ( SignInfo.lpszSubjectName) VirtualFree(SignInfo.lpszSubjectName, 0, MEM_RELEASE);

        return 0;
    }
}

WinVerifyTrust检查特定签名？

4 个答案: