How to trigger "BadImageFormatException'? - c#

I need to create a "BadimageFormatException" in my local to test some cacheing issue. How to create "BadImageFormatException"?

As already specified in the comments, you can just create and throw this exception:
throw new BadImageFormatException();
If you want to cause this exception naturally, then as per MSDN documentation,
This exception is thrown when the file format of a dynamic link library (.dll file) or an executable (.exe file) doesn't conform to the format that the common language runtime expects
It means that you can cause it by trying to load an invalid assembly file:
string tempPath = Path.GetTempFileName();
using (var file = File.OpenWrite(tempPath))
using (var sw = new StreamWriter(file))
{
sw.WriteLine("I am not an assembly");
}
Assembly.LoadFile(tempPath);
Thanks to #Xiaoy312 for the advice. There is a much simpler way to do this using Assembly.Load:
Assembly.Load(new byte[] { 0 });

If new to this, then one way also is to load an unmanaged assembly for example notepad.exe.
try
{
// path to notepad.exe.
string path = Environment.ExpandEnvironmentVariables("%windir%") + #"\System32\notepad.exe";
Assembly assembly = Assembly.LoadFile(path);
}
catch (System.BadImageFormatException exception)
{
// catch an exception.
}
As Notepad is unmanaged and not compiled with .Net, .net isnt very happy and throws the exception.
For interesting trivia, BadImageFormatException has nothing to do with bad image format like gifs or jpegs but its an exception when .Net attempts to load a DLL or exe which isnt compatible with CLR.
Also, all exceptions are derived from System.Exception. BadImageFormatException is just inherited from System.Exception.

Related

Embedding SQLite.Interop.dll in C#

I have an application that has all the DLL files it needs embedded into it so that it is a standalone exe. Here is how I am loading everything now:
public static Assembly ExecutingAssembly = Assembly.GetExecutingAssembly();
public static string[] EmbeddedLibraries = ExecutingAssembly.GetManifestResourceNames().Where(x => x.EndsWith(".dll")).ToArray();
public static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args) {
// Get assembly name
var assemblyName = new AssemblyName(args.Name).Name + ".dll";
// Get resource name
var resourceName = EmbeddedLibraries.FirstOrDefault(x => x.EndsWith(assemblyName));
if (resourceName == null) {
return null;
}
// Load assembly from resource
using (var stream = ExecutingAssembly.GetManifestResourceStream(resourceName)) {
var bytes = new byte[stream.Length];
stream.Read(bytes, 0, bytes.Length);
return Assembly.Load(bytes);
}
}
public static void Main(string[] arg) {
AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
RealMain();
}
So the first interesting thing I noticed is that it only loads the DLL files that are used in the first page. It isn't enough to put using System.Data.SQLite; at the top to get it to include System.Data.SQLite.dll, you also have to do something that touches that namespace right away.
The next issue involves SQLite.Interop.dll which it won't load into the assembly. When you try you get the following error:
Exception thrown: 'System.BadImageFormatException' in mscorlib.dll
An unhandled exception of type 'System.BadImageFormatException' occurred in mscorlib.dll
The module was expected to contain an assembly manifest. (Exception from HRESULT: 0x80131018)
Now I could unpack the DLL and copy it to the c:\Windows\System32 directory, but since everything else is self contained, it would be nice if this was as well. I noticed this SDK that claims to be able to create it as a virtual file:
https://www.boxedapp.com/boxedappsdk/usecases/embed_system.data.sqlite.dll_dependencies.html
Is there a way to do this without the extra SDK? Or as an alternative, is there another way of creating and using SQLite databases without that DLL using a different package? I tried 3-4 different packages yesterday and didn't get anywhere.
SOLUTION
Ok, so this is disappointing that it is so easy, and yet nowhere else did I see the solution in dozens of other SO questions. On the SQLite.org website, there are a couple different downloads to choose from. When you use the NuGet package manager, you get the wrong version if what you want to do is embed everything.
To do it right, go to: https://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki
On that page you will want to download the BUNDLE version. In my case that was sqlite-netFx46-static-binary-bundle-Win32-2015-1.0.112.0.zip
Manually add that as a resource, include in your application as an Embedded Resource (Those are 2 separate steps), set it to not copy to output directory and use the code from the question to have it added.

TargetInvocationException.InnerException missing line numbers

I'm executing some code from dynamically loaded assembly using Invoke. Out of curiosity I've thrown an exception in the method I invoke. It works and I can read the exception but it's missing line numbers.
var assemblyBytes = File.ReadAllBytes(scriptPath);
// I'm using this overload to avoid blocking the dll.
var assembly = Assembly.Load(assemblyBytes); // allows to pass pdb bytes in the second argument.
var myMethod = ...
try
{
myMethod.Invoke(null, parameters);
}
catch (TargetInvocationException e)
{
MessageBox.Show(e.InnerException); // missing line numbers
}
Dynamically loaded assembly was built in debug mode.
Any idea why that happens, and how can I get it to show line numbers?
In this case I'm using .NET Framework 4.0
passing pdb bytes to Assembly.Load worked

C# exception not being thrown/caught

I am trying to load dlls into my program at runtime that match a specific assembly attribute that I have set. In order to make sure that the dll is loadable before I check its flag I have written the following method:
private bool IsValidDll(string dll) {
try {
System.Reflection.Assembly.LoadFrom(dll);
return true;
} catch (Exception ex) { return false; }
}
I can loop through dlls in my current directory and call this method to see if it will be safe to load the dll and check its assembly attributes. However, I am hitting a dll that is not throwing/catching an Exception and is still just directly crashing the program. The relevant output window information is as follows:
LoaderException: System.IO.FileLoadException: Mixed mode assembly is built against
version 'v2.0.50727' of the runtime and cannot be loaded in the 4.0 runtime without additional configuration information. - Adapters.Spryware.SprywareAdapter
System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.
I have tried catching the specific Exception (System.IO.FileLoadException) but the catch block is still skipped over and I still crash. Any thoughts?
Also, I find that this is a pretty heavy handed way of checking for my assembly attribute. Is there a way to check for my flag without having to load the dll with Reflection first?
Have to confess, I dont see why your code doesnt work either:
I made a .net 4 thing and ran and mine did catch it:
private void button1_Click(object sender, EventArgs e)
{
// foreach (String file in Directory.GetFiles("c:\\windows", "*.dll"))
String file = #"C:\Windows\Microsoft.NET\Framework64\v2.0.50727\System.Data.dll";
{
try
{
//System.Reflection.Assembly.ReflectionOnlyLoadFrom(file);
System.Reflection.Assembly.LoadFrom(file);
}
catch (Exception ee)
{
textBox1.Text += ee.Message + Environment.NewLine;
}
}
}
On clicking the text box reads:
Could not load file or assembly 'file:///C:\Windows\Microsoft.NET\Framework64\v2.0.50727\System.Data.dll' or one of its dependencies. An attempt was made to load a program with an incorrect format.
You can probably solve this problem and be less heavy handed by loading the assemblies into the reflection-only context.
Basically, instead of fully loading the assembly, this gives you the ability to reflect over the assembly without the ability to do things like instantiate objects. This expressly allows you to look at assemblies that are built against different .NET framework versions than the one on which your application is running.
A thorough treatment is available on MSDN: http://msdn.microsoft.com/en-us/library/ms172331.aspx

Reading the Version number from a AssemblyInfo.cs file

I'm trying to extract the version number from a AssemblyInfo.cs file!
And I'm trying to use System.Reflection.Assembly.LoadFile(path); But while doing this I get a BadImageFormatException; "The module was expected to contain an assembly manifest. (Exception from HRESULT: 0x80131018)". So now I wounder, is that not a possible way to go about it? And should I use RegEx instead?
I have read many examples with GetExecutingAssembly() but I do want to get the version from an other project.
Clarification: I want to read the version info from the AssemblyInfo.cs file! And not from a compiled file. I'm trying to make a tool to update my version numbers before I make a new release.
You can get Assembly version without loading it as:
using System.Reflection;
using System.IO;
...
// Get assembly
AssemblyName currentAssembly = AssemblyName.GetAssemblyName(path);
Version assemblyVersion = currentAssembly.Version;
Edit:
If you want to read file then you can do it like this:
string path = #"d:\AssemblyInfo.cs";
if (File.Exists(path))
{
// Open the file to read from.
string[] readText = File.ReadAllLines(path);
var versionInfoLines = readText.Where(t => t.Contains("[assembly: AssemblyVersion"));
foreach (string item in versionInfoLines)
{
string version = item.Substring(item.IndexOf('(') + 2, item.LastIndexOf(')') - item.IndexOf('(') - 3);
//Console.WriteLine(Regex.Replace(version, #"\P{S}", string.Empty));
Console.WriteLine(version);
}
}
//Output
1.0.*
1.0.0.0
Hope this help...
You can specify the target assembly path in AssemblyName.GetAssemblyName
AssemblyName.GetAssemblyName("ProjectB.exe").Version
AssemblyInfo.cs file gets compiled to IL assembly.
If you load that assembly you can read the version with all the examples that you have already seen. Which is reading an embedded version information from a compiled assembly file, and it may be overwritten by compilation process to a value different from what is in AssemblyInfo.cs
However it sounds like what you want instead is to read a version number from AssemblyInfo.cs text file, without compiling it down.
If this is the case you really just have to use regex with a format appropriate for your project, or even come up with a convention that will keep it simple.
This could be as simple as
var versionMatch = Regex.Match(File.ReadAllText(filename), #"AssemblyVersion\s*\(\s*""([0-9\.\*]*?)""\s*\)");
if (versionMatch.Success)
{
Console.WriteLine(versionMatch.Groups[1].Value);
}
You would have to consider convention around what goes there, since 1.0.* is a valid version string that translates to timestamp values of form 1.0.nnn.mmm at compile time, and nnn and mmm part closely guessable but not precisely guessable.
It sounds like you're trying to load an assembly compiled for x86 in an x64 environment or vice-versa.
Ensure the assembly this code resides in is built for the same environment as the target and you can get it with the examples it sounds like you've read.
You can proceed with Assembly.GetName().Version where your assembly could be the type of your class
public class Test
{
public static void Main()
{
Console.WriteLine("Current assembly : " + typeof(Test).Assembly.GetName().Version);
}
}
For the test application I have working on, shows me below details using above code:

why reflection.assembly loadfile doesn't load all dlls?

I am using LoadFrom(), to load dlls, but for some reason this load function doesn't work on all dlls,
i want to load 3000 dlls to get from each one the copyright attribute.
my code :
class ReverseDLL
{
private Assembly assembly;
private AssemblyDescriptionAttribute desc;
private AssemblyTitleAttribute title;
private AssemblyCopyrightAttribute copyRight;
public string getCopyright(string path)
{
try
{
//assembly = System.Reflection.Assembly.Load(System.IO.File.ReadAllBytes(path));
assembly = System.Reflection.Assembly.LoadFrom(path);//"C:\\Windows\\winsxs\\x86_microsoft.vc90.debugcrt_1fc8b3b9a1e18e3b_9.0.30729.1_none_bb1f6aa1308c35eb\\msvcm90d.dll");//path);// LoadFrom(path);
desc = (AssemblyDescriptionAttribute)
AssemblyDescriptionAttribute.GetCustomAttribute(
assembly, typeof(AssemblyDescriptionAttribute));
title = (AssemblyTitleAttribute)
AssemblyTitleAttribute.GetCustomAttribute(
assembly, typeof(AssemblyTitleAttribute));
copyRight = (AssemblyCopyrightAttribute)AssemblyCopyrightAttribute.GetCustomAttribute(assembly, typeof(AssemblyCopyrightAttribute));
}
catch
{
this.copyRight = new AssemblyCopyrightAttribute("");
}
if (this.copyRight == null)
this.copyRight = new AssemblyCopyrightAttribute("");
return copyRight.Copyright;
}
}
I don't know about the reflection problem without you providing more info (such as the error), but you could also try access the file itself:
string copyright = FileVersionInfo.GetVersionInfo(path).LegalCopyright;
This accesses the file-system meta-data (like you would see in explorer), and has the advantage of working for both managed and unmanaged dlls; but it requires that meta-data to exist (it doesn't look at the attribute).
Edit: a quick check indicates that (as expected) the compiler does check for this attribute and populate the file meta-data correctly.
Have you tried stopping on exceptions? Ctrl + Alt + E, stop on framework exceptions when they are thrown. The exception message should give you some information as to why the DLL couldn't be loaded.
Using reflection is not the optimal approach, as some of the dll may have dependencies you don't have.
Using a metadata parser can give you the things you want,
http://ccimetadata.codeplex.com/
http://www.mono-project.com/Cecil
The way Marc mentioned does not work for most .NET specific metadata.

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