使用哈希以编程方式比较两个 DLL 文件
使用哈希以编程方式比较两个 DLL 文件
在过去的日子里，我需要比较两个 .NET 程序集，看看它们在功能上是否相同。您可能知道，当您多次构建同一个项目时，生成的输出.dll或.exe文件总是不同的。这是因为ModuleVerisonId 属性(MVID)。因此，为了检查两个程序集是否相同，我们可以将它们反汇编为IL 代码并进行比较。反汇编文件的最简单方法是使用MSIL Disassembler。但是，它不在一个公共位置。它可以位于以下任何位置：
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C:\Program Files\Microsoft SDKs\Windows\v6.0\bin\ildasm.exe C:\Program Files\Microsoft SDKs\Windows\v6.0A\bin\ildasm.exe C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin\ildasm.exe C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin\x64\ildasm.exe C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin\NETFX 4.0 Tools\ildasm.exe C:\Program Files\Microsoft SDKs\Windows\v7.0A\bin\NETFX 4.0 Tools\x64\ildasm.exe C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\bin\ildasm.exe C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\bin\x64\ildasm.exe C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\bin\NETFX 4.0 Tools\ildasm.exe C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\bin\NETFX 4.0 Tools\x64\ildasm.exe
因此，在我的以下解决方案中，我将ildasm.exe文件嵌入到了一个类库中，以便能够在任何机器上使用它。当我们反汇编一个程序集时，我们检查执行程序集文件夹中是否存在ildasm.exe文件，如果不存在，则从我们的 DLL 文件中提取该文件。使用ildasm文件，我们获取 IL 代码并将其保存到一个临时文件中。然后我们需要删除以下三行：
- MVID - 正如我之前写的，这是每次构建时生成的唯一 GUID
- 图像库（图像库告诉我们程序将被 Windows 加载器加载到内存中的哪个位置。） - 这对于每个构建也是不同的
- 时间日期戳-在当时间和日期
ildasm运行
所以我们读取临时文件内容，删除这些我们使用正则表达式的行，然后将文件内容保存到同一个文件中。您可以在此处找到反汇编程序文件：
C＃
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using System;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Diagnostics;
using System.Text.RegularExpressions;
namespace FileHasher
{
public class Disassembler
{
public static Regex regexMVID = new Regex("//\\s*MVID\\:\\s*\\{[a-zA-Z0-9\\-]+\\}",
RegexOptions.Multiline | RegexOptions.Compiled);
public static Regex regexImageBase = new Regex("//\\s*Image\\s+base\\:\\s0x[0-9A-Fa-f]*",
RegexOptions.Multiline | RegexOptions.Compiled);
public static Regex regexTimeStamp = new Regex("//\\s*Time-date\\s+stamp\\:\\s*0x[0-9A-Fa-f]*",
RegexOptions.Multiline | RegexOptions.Compiled);
private static readonly Lazy<Assembly> currentAssembly = new Lazy<Assembly>(() =>
{
return MethodBase.GetCurrentMethod().DeclaringType.Assembly;
});
private static readonly Lazy<string> executingAssemblyPath = new Lazy<string>(() =>
{
return Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
});
private static readonly Lazy<string> currentAssemblyFolder = new Lazy<string>(() =>
{
return Path.GetDirectoryName(currentAssembly.Value.Location);
});
private static readonly Lazy<string[]> arrResources = new Lazy<string[]>(() =>
{
return currentAssembly.Value.GetManifestResourceNames();
});
private const string ildasmArguments = "/all /text \"{0}\"";
public static string ILDasmFileLocation
{
get
{
return Path.Combine(executingAssemblyPath.Value, "ildasm.exe");
}
}
static Disassembler()
{
//extract the ildasm file to the executing assembly location
ExtractFileToLocation("ildasm.exe", ILDasmFileLocation);
}
/// <summary>
/// Saves the file from embedded resource to a given location.
/// </summary>
/// <param name="embeddedResourceName">Name of the embedded resource.</param>
/// <param name="fileName">Name of the file.</param>
protected static void SaveFileFromEmbeddedResource(string embeddedResourceName, string fileName)
{
if (File.Exists(fileName))
{
//the file already exists,
//we can add deletion here if we want to change the version of the 7zip
return;
}
FileInfo fileInfoOutputFile = new FileInfo(fileName);
using (FileStream streamToOutputFile = fileInfoOutputFile.OpenWrite())
using (Stream streamToResourceFile =
currentAssembly.Value.GetManifestResourceStream(embeddedResourceName))
{
const int size = 4096;
byte[] bytes = new byte[4096];
int numBytes;
while ((numBytes = streamToResourceFile.Read(bytes, 0, size)) > 0)
{
streamToOutputFile.Write(bytes, 0, numBytes);
}
streamToOutputFile.Close();
streamToResourceFile.Close();
}
}
/// <summary>
/// Searches the embedded resource and extracts it to the given location.
/// </summary>
/// <param name="fileNameInDll">The file name in DLL.</param>
/// <param name="outFileName">Name of the out file.</param>
protected static void ExtractFileToLocation(string fileNameInDll, string outFileName)
{
string resourcePath = arrResources.Value.Where(resource => resource.EndsWith(
fileNameInDll, StringComparison.InvariantCultureIgnoreCase)).FirstOrDefault();
if (resourcePath == null)
{
throw new Exception(string.Format("Cannot find {0} in " +
"the embedded resources of {1}", fileNameInDll, currentAssembly.Value.FullName));
}
SaveFileFromEmbeddedResource(resourcePath, outFileName);
}
public static string GetDisassembledFile(string assemblyFilePath)
{
if (!File.Exists(assemblyFilePath))
{
throw new InvalidOperationException(string.Format
("The file {0} does not exist!", assemblyFilePath));
}
string tempFileName = Path.GetTempFileName();
var startInfo = new ProcessStartInfo(ILDasmFileLocation,
string.Format(ildasmArguments, assemblyFilePath));
startInfo.WindowStyle = ProcessWindowStyle.Hidden;
startInfo.CreateNoWindow = true;
startInfo.UseShellExecute = false;
startInfo.RedirectStandardOutput = true;
using (var process = System.Diagnostics.Process.Start(startInfo))
{
string output = process.StandardOutput.ReadToEnd();
process.WaitForExit();
if (process.ExitCode > 0)
{
throw new InvalidOperationException(
string.Format
("Generating IL code for file {0} failed with exit code - {1}. Log: {2}",
assemblyFilePath, process.ExitCode, output));
}
File.WriteAllText(tempFileName, output);
}
RemoveUnnededRows(tempFileName);
return tempFileName;
}
private static void RemoveUnnededRows(string fileName)
{
string fileContent = File.ReadAllText(fileName);
//remove MVID
fileContent = regexMVID.Replace(fileContent, string.Empty);
//remove Image Base
fileContent = regexImageBase.Replace(fileContent, string.Empty);
//remove Time Stamp
fileContent = regexTimeStamp.Replace(fileContent, string.Empty);
File.WriteAllText(fileName, fileContent);
}
public static string DisassembleFile(string assemblyFilePath)
{
string disassembledFile = GetDisassembledFile(assemblyFilePath);
try
{
return File.ReadAllText(disassembledFile);
}
finally
{
if (File.Exists(disassembledFile))
{
File.Delete(disassembledFile);
}
}
}
}
}
所以使用这个类，我们可以获得.NET程序集的IL代码。现在，我们可以创建一个Hash计算器来计算文件的哈希值，以便我们可以存储hash它并将其与较新的文件进行比较。为了计算哈希，我使用以下方法：
- 检查文件是否以.dll或 .exe结尾- 如果是，这可能是 .NET 程序集，如果没有获取文件哈希
- 尝试打开程序集
Assembly.LoadFile以查看这是否是有效的 .NET 程序集，如果有BadImageFormatException，则这不是.NET 程序集，因此获取文件哈希 - 如果这是一个 .NET 程序集，则获取 IL 代码文件并计算其哈希值。
为了计算文件哈希，我们使用MD5CryptoServiceProvider. 所以，这是Hash计算器：
C＃
缩小▲ 复制代码
using System;
using System.IO;
using System.Reflection;
namespace FileHasher
{
public class HashCalculator
{
public string FileName { get; private set; }
public HashCalculator(string fileName)
{
this.FileName = fileName;
}
public string CalculateFileHash()
{
if (Path.GetExtension(this.FileName).Equals(".dll",
System.StringComparison.InvariantCultureIgnoreCase)
|| Path.GetExtension(this.FileName).Equals(".exe",
System.StringComparison.InvariantCultureIgnoreCase))
{
return GetAssemblyFileHash();
}
else
{
return GetFileHash();
}
}
private string GetFileHash()
{
return CalculateHashFromStream(File.OpenRead(this.FileName));
}
private string GetAssemblyFileHash()
{
string tempFileName = null;
try
{
//try to open the assembly to check if this is a .NET one
var assembly = Assembly.LoadFile(this.FileName);
tempFileName = Disassembler.GetDisassembledFile(this.FileName);
return CalculateHashFromStream(File.OpenRead(tempFileName));
}
catch(BadImageFormatException)
{
return GetFileHash();
}
finally
{
if (File.Exists(tempFileName))
{
File.Delete(tempFileName);
}
}
}
private string CalculateHashFromStream(Stream stream)
{
using (var readerSource = new System.IO.BufferedStream(stream, 1200000))
{
using (var md51 = new System.Security.Cryptography.MD5CryptoServiceProvider())
{
md51.ComputeHash(readerSource);
return Convert.ToBase64String(md51.Hash);
}
}
}
}
}
您可以在此处找到代码。
https://www.codeproject.com/Articles/501631/Compare-Two-DLL-Files-Programmatically-Using-Hash
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