windows WinVerifyTrust 检查特定签名？

WinVerifyTrust to check for a specific signature?

提问by joshk0

I'm implementing a process elevation helper for Windows. It's a program that will run in elevated mode and launch other programs with administrator privileges without displaying additional UAC prompts. For security reasons, I want to make sure only binaries that are digitally signed with my company's Authenticode key can be executed.

我正在为 Windows 实现进程提升助手。这是一个将在提升模式下运行并以管理员权限启动其他程序而不显示额外 UAC 提示的程序。出于安全原因，我想确保只能执行使用我公司的 Authenticode 密钥进行数字签名的二进制文件。

The WinVerifyTrustfunction gets me halfway there, but it only ensures that a binary is signed by somekey that is part of Microsoft's chain of trust. Is there a relatively simple way to perform the Authenticode verification AND ensure that it is signed by our private key?

该的WinVerifyTrust函数获取我中途有，但它只是确保了二进制通过签署一些关键的就是信任的微软链的一部分。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？

采纳答案by Kevin Montrose

I believe what you're looking for is CryptQueryObject.

我相信您正在寻找的是CryptQueryObject。

With it you should be able to pull the involved certificate out of a PE, and do any additional checks you want.

有了它，您应该能够从 PE 中提取所涉及的证书，并进行您想要的任何其他检查。

---

---

By way of example, this will get you to a HCRYPTMSG. From there you can use CryptMsgGetParamto pull out whatever you want. I'd hoped to make something more 'robust', but these APIs are pretty hairy insomuch as they require a lot of branching to handle all their return cases.

举例来说，这将使您获得 HCRYPTMSG。从那里你可以使用CryptMsgGetParam来拉出你想要的任何东西。我希望做一些更“健壮”的东西，但这些 API 非常麻烦，因为它们需要大量分支来处理所有返回情况。

So, here's a p/invoke-rific c# example (I started in C, but that was basically unreadable):

所以，这是 ap/invoke-rific c# 示例（我从 C 开始，但基本上不可读）：

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;
    }

回答by Kevin Montrose

To get the certificate information from signed code use this:

要从签名代码中获取证书信息，请使用：

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

Then you can get the cert details like this:

然后你可以得到这样的证书详细信息：

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

回答by bobince

these are some of the nastiest APIs I've ever worked with

这些是我曾经使用过的一些最讨厌的 API

A word of warning: it's worse than you already thought.

一个警告：它比你想象的更糟。

At least since introducing SHA-256 signing (has this always been the case?), it's possible for Authenticode to have multiple signatures. They're not encoded as multiple signatures in the PKCS-7 signature message; instead, they're unauthenticated message attributes of type OID_NESTED_SIGNATURE, each containing another complete PKCS-7 signature message.

至少自从引入 SHA-256 签名（一直都是这种情况？），Authenticode 可能有多个签名。它们没有在 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，每个属性都包含另一个完整的 PKCS-7 签名消息。

WinVerifyTrust will tell you the file is valid if any of the signatures are valid and come from a trusted certificate chain. However it won't tell you which of the signatures was valid. If you then use CryptQueryObject to read the full PKCS-7 message, and only look at the certificate for the primary signature (as in the code samples here and on MSDN), you're not necessarily looking at a verified certificate. The associated signature might not match the executable, and/or the certificate might not have a trusted CA chain.

如果任何签名有效并且来自受信任的证书链，WinVerifyTrust 将告诉您该文件是有效的。但是，它不会告诉您哪些签名是有效的。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 上的代码示例中所示），则您不一定要查看经过验证的证书。关联的签名可能与可执行文件不匹配，和/或证书可能没有受信任的 CA 链。

If you're using the details of the primary signature to validate that the certificate is one your software trusts, you're vulnerable to a situation where WinVerifyTrust is trusting a secondary signature, but your code is checking the primary signature's certificate is what you expected, and you haven't noticed that the signature from the primary certificate is nonsense. An attacker could use your public certificate without owning its private key, combined with some other code-signing certificate issued to someone else, to bypass a publisher check this way.

如果您使用主要签名的详细信息来验证证书是否是您的软件信任的证书，则您很容易出现 WinVerifyTrust 信任次要签名但您的代码正在检查主要签名的证书是否符合您的预期的情况，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，并结合其他一些颁发给其他人的代码签名证书，以这种方式绕过发布者检查。

From Win8 onwards, WinVerifyTrust can optionally validate specific signatures, so you should be able to iterate the signatures to find one that is valid andone that satisfies your requirements.

从 Win8 开始，WinVerifyTrust 可以选择性地验证特定的签名，因此您应该能够迭代签名以找到有效的签名和满足您要求的签名。

If you have to be Win7-compatible, though, as far as I know the best you can manage is MsiGetFileSignatureInformation. From experimentation (as for everything else here, the actual documentation is frustratingly woolly), it seems to return the trusted certificate when WinVerifyTrust trusts one. But if there isn't a trusted signature, it returns the primary signature's certificate anyway, so you still have to use WinVerifyTrust to check that first.

但是，如果您必须兼容 Win7，据我所知，您可以管理的最好方法是 MsiGetFileSignatureInformation。根据实验（至于这里的其他所有内容，实际文档令人沮丧地毛茸茸），当 WinVerifyTrust 信任一个证书时，它似乎返回受信任的证书。但是如果没有受信任的签名，它无论如何都会返回主签名的证书，因此您仍然必须先使用 WinVerifyTrust 进行检查。

Of course there also plenty of possible time-of-check/time-of-use problems here.

当然，这里也有很多可能的检查时间/使用时间问题。

回答by nir

found the solution here:

在这里找到了解决方案：

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

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

here it is with indentation:

这是带有缩进的：

#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;
    }
}