Question

是否可以检查动态加载的程序集是否已使用特定的强名称进行签名？

比较 AssemblyName.GetPublicKey（）方法返回的值是否足够/安全？

Assembly loaded = Assembly.LoadFile(path);

byte[] evidenceKey = loaded.GetName().GetPublicKey();

if (evidenceKey != null)
{
    byte[] internalKey = Assembly.GetExecutingAssembly().GetName().GetPublicKey();

    if (evidenceKey.SequenceEqual(internalKey))
    {
        return extension;
    }
}

这不能被欺骗吗？我不确定SetPublicKey（）方法是否对构建的程序集有任何影响，但即使是MSDN文档也显示了如何在动态生成的程序集（反射发射）上使用它，这意味着你可以从中提取公钥。托管应用程序并将其注入您自己的程序集并运行恶意代码，如果以上是安全防范，或者我错过了什么？

是否有更正确和安全的方法？我知道如果相反的情况是这种情况，也就是说，我想要保护程序集只被签名主机调用，那么我可以使用StrongNameIdentityPermission属性标记程序集。

Answer 1

没有可管理的方法来检查程序集的签名，并且检查公钥会使您容易受到欺骗。您必须使用P/Invoke并调用 StrongNameSignatureVerificationEx 功能来检查签名

[DllImport("mscoree.dll", CharSet=CharSet.Unicode)]
static extern bool StrongNameSignatureVerificationEx(string wszFilePath, bool fForceVerification, ref bool  pfWasVerified);

Answer 2

装配完成后测试强名称没什么意义。攻击者可以简单地在程序集中注入模块构造函数并执行任何所需的代码。该框架的.NET 3.5 SP1版本也紧随其后，不再验证从受信任位置加载的程序集的强名称。启动时间提高了约40％。

关键点在于：一旦攻击者将机器危害到能够在应用程序的探测路径中注入程序集的程度，他就不会费心去做。他只是替换你的EXE文件。

Answer 3

根据http://msdn.microsoft.com/pl-pl/library/ms232579.aspx，在.NET 4下不推荐使用mscoree.dll中的StrongNameSignatureVerificationEx检查强名称。

.NET 4的做法是：

var clrStrongName = (IClrStrongName)RuntimeEnvironment.GetRuntimeInterfaceAsObject(new Guid("B79B0ACD-F5CD-409b-B5A5-A16244610B92"), new Guid("9FD93CCF-3280-4391-B3A9-96E1CDE77C8D"));
bool verificationForced;
int result = clrStrongName.StrongNameSignatureVerificationEx(@"PATH\TO\ASSEMBLY.DLL", true, out verificationForced);
if (result == 0)
{
    Console.WriteLine("Valid.");
}



[ComConversionLoss, Guid("9FD93CCF-3280-4391-B3A9-96E1CDE77C8D"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown), SecurityCritical]
[ComImport]
internal interface IClrStrongName
{
    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int GetHashFromAssemblyFile([MarshalAs(UnmanagedType.LPStr)] [In] string pszFilePath, [MarshalAs(UnmanagedType.U4)] [In] [Out] ref int piHashAlg, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] [Out] byte[] pbHash, [MarshalAs(UnmanagedType.U4)] [In] int cchHash, [MarshalAs(UnmanagedType.U4)] out int pchHash);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int GetHashFromAssemblyFileW([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzFilePath, [MarshalAs(UnmanagedType.U4)] [In] [Out] ref int piHashAlg, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] [Out] byte[] pbHash, [MarshalAs(UnmanagedType.U4)] [In] int cchHash, [MarshalAs(UnmanagedType.U4)] out int pchHash);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int GetHashFromBlob([In] IntPtr pbBlob, [MarshalAs(UnmanagedType.U4)] [In] int cchBlob, [MarshalAs(UnmanagedType.U4)] [In] [Out] ref int piHashAlg, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 4)] [Out] byte[] pbHash, [MarshalAs(UnmanagedType.U4)] [In] int cchHash, [MarshalAs(UnmanagedType.U4)] out int pchHash);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int GetHashFromFile([MarshalAs(UnmanagedType.LPStr)] [In] string pszFilePath, [MarshalAs(UnmanagedType.U4)] [In] [Out] ref int piHashAlg, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] [Out] byte[] pbHash, [MarshalAs(UnmanagedType.U4)] [In] int cchHash, [MarshalAs(UnmanagedType.U4)] out int pchHash);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int GetHashFromFileW([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzFilePath, [MarshalAs(UnmanagedType.U4)] [In] [Out] ref int piHashAlg, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] [Out] byte[] pbHash, [MarshalAs(UnmanagedType.U4)] [In] int cchHash, [MarshalAs(UnmanagedType.U4)] out int pchHash);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int GetHashFromHandle([In] IntPtr hFile, [MarshalAs(UnmanagedType.U4)] [In] [Out] ref int piHashAlg, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] [Out] byte[] pbHash, [MarshalAs(UnmanagedType.U4)] [In] int cchHash, [MarshalAs(UnmanagedType.U4)] out int pchHash);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    [return: MarshalAs(UnmanagedType.U4)]
    int StrongNameCompareAssemblies([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzAssembly1, [MarshalAs(UnmanagedType.LPWStr)] [In] string pwzAssembly2, [MarshalAs(UnmanagedType.U4)] out int dwResult);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameFreeBuffer([In] IntPtr pbMemory);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameGetBlob([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzFilePath, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] [Out] byte[] pbBlob, [MarshalAs(UnmanagedType.U4)] [In] [Out] ref int pcbBlob);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameGetBlobFromImage([In] IntPtr pbBase, [MarshalAs(UnmanagedType.U4)] [In] int dwLength, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] [Out] byte[] pbBlob, [MarshalAs(UnmanagedType.U4)] [In] [Out] ref int pcbBlob);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameGetPublicKey([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzKeyContainer, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] [In] byte[] pbKeyBlob, [MarshalAs(UnmanagedType.U4)] [In] int cbKeyBlob, out IntPtr ppbPublicKeyBlob, [MarshalAs(UnmanagedType.U4)] out int pcbPublicKeyBlob);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    [return: MarshalAs(UnmanagedType.U4)]
    int StrongNameHashSize([MarshalAs(UnmanagedType.U4)] [In] int ulHashAlg, [MarshalAs(UnmanagedType.U4)] out int cbSize);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameKeyDelete([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzKeyContainer);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameKeyGen([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzKeyContainer, [MarshalAs(UnmanagedType.U4)] [In] int dwFlags, out IntPtr ppbKeyBlob, [MarshalAs(UnmanagedType.U4)] out int pcbKeyBlob);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameKeyGenEx([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzKeyContainer, [MarshalAs(UnmanagedType.U4)] [In] int dwFlags, [MarshalAs(UnmanagedType.U4)] [In] int dwKeySize, out IntPtr ppbKeyBlob, [MarshalAs(UnmanagedType.U4)] out int pcbKeyBlob);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameKeyInstall([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzKeyContainer, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 2)] [In] byte[] pbKeyBlob, [MarshalAs(UnmanagedType.U4)] [In] int cbKeyBlob);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameSignatureGeneration([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzFilePath, [MarshalAs(UnmanagedType.LPWStr)] [In] string pwzKeyContainer, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] [In] byte[] pbKeyBlob, [MarshalAs(UnmanagedType.U4)] [In] int cbKeyBlob, [In] [Out] IntPtr ppbSignatureBlob, [MarshalAs(UnmanagedType.U4)] out int pcbSignatureBlob);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameSignatureGenerationEx([MarshalAs(UnmanagedType.LPWStr)] [In] string wszFilePath, [MarshalAs(UnmanagedType.LPWStr)] [In] string wszKeyContainer, [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 3)] [In] byte[] pbKeyBlob, [MarshalAs(UnmanagedType.U4)] [In] int cbKeyBlob, [In] [Out] IntPtr ppbSignatureBlob, [MarshalAs(UnmanagedType.U4)] out int pcbSignatureBlob, [MarshalAs(UnmanagedType.U4)] [In] int dwFlags);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameSignatureSize([MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)] [In] byte[] pbPublicKeyBlob, [MarshalAs(UnmanagedType.U4)] [In] int cbPublicKeyBlob, [MarshalAs(UnmanagedType.U4)] out int pcbSize);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    [return: MarshalAs(UnmanagedType.U4)]
    int StrongNameSignatureVerification([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzFilePath, [MarshalAs(UnmanagedType.U4)] [In] int dwInFlags, [MarshalAs(UnmanagedType.U4)] out int dwOutFlags);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    [return: MarshalAs(UnmanagedType.U4)]
    int StrongNameSignatureVerificationEx([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzFilePath, [MarshalAs(UnmanagedType.I1)] [In] bool fForceVerification, [MarshalAs(UnmanagedType.I1)] out bool fWasVerified);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    [return: MarshalAs(UnmanagedType.U4)]
    int StrongNameSignatureVerificationFromImage([In] IntPtr pbBase, [MarshalAs(UnmanagedType.U4)] [In] int dwLength, [MarshalAs(UnmanagedType.U4)] [In] int dwInFlags, [MarshalAs(UnmanagedType.U4)] out int dwOutFlags);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameTokenFromAssembly([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzFilePath, out IntPtr ppbStrongNameToken, [MarshalAs(UnmanagedType.U4)] out int pcbStrongNameToken);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameTokenFromAssemblyEx([MarshalAs(UnmanagedType.LPWStr)] [In] string pwzFilePath, out IntPtr ppbStrongNameToken, [MarshalAs(UnmanagedType.U4)] out int pcbStrongNameToken, out IntPtr ppbPublicKeyBlob, [MarshalAs(UnmanagedType.U4)] out int pcbPublicKeyBlob);

    [MethodImpl(MethodImplOptions.PreserveSig | MethodImplOptions.InternalCall)]
    int StrongNameTokenFromPublicKey([MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1)] [In] byte[] pbPublicKeyBlob, [MarshalAs(UnmanagedType.U4)] [In] int cbPublicKeyBlob, out IntPtr ppbStrongNameToken, [MarshalAs(UnmanagedType.U4)] out int pcbStrongNameToken);
}

检查程序集是否有强名称

3 个答案: