I would like to determine whether or not a file has any dependencies to the .net framework. The catch: I want to do this without the use of any third party application.
I was hoping there was some hidden method in existence that I could use for this.
Thanks for any help,
Evan
Something along these lines:
Assembly a = Assembly.LoadFrom(
pathToAssembly);
AssemblyName [] an =
a.GetReferencedAssemblies();
foreach (AssemblyName name in an)
Console.WriteLine(name.ToString());
... Courtesy of Determining .NET Assembly and Method References
A .NET executable has special fields in its header that you can look for, but even native EXEs can implicitly rely on .NET, say by invoking a COM service that's written in .NET.
By nature, a C# application will most likely link against the standard C# libraries. If you are talking about another library, outside of the standard libraries, I don't know if that is possible. What exactly do you mean by 'third party' in this situation?
Related
I have a dll library that I use in one of my projects. I don't want others to be able to link and access the methods in the library. Is it possible to protect it? Thanks!
EDIT: Is there a way to 'hide' method names or make them random inside dll?
You can attempt to limit its use by requireing a key. If a wrong key is passed, your library will not work.
This however can be easily circumvented by decompiling your application and check what key you supply and simply use the same key.
Another possibility would be to add a check to every public method on every public class. That check would verify that the calling assembly is one of yours.
Depending on the implementation of this check, it is easily circumvented by creating a small proxy assembly that is named the same as one of yours.
In general: It is not possible to prevent it. Just like with copy protection, everything can be circumvented if the other party has access to your assembly - and I mean the compiled assembly, not the source code.
Short answer is no. If somebody wants access to your library they will find a way.
You can obfuscate your library to make things harder for them however, but there is no sure-fire way of preventing them.
One way is Friend Assemblies
You can mark your assembly internal and only specified assemblies can access your library.
But it just forbids to use your library in "easy way".
You can protect your libraries and executables from anuthorized using with help of third party products like Sentinel Hasp, but it will cost to your application in performance, cost to you some money and it is not garanteed that nobody will break it.
But to break protection pirates should work hard.
I want to create a single dll that is merged with a 3rd party dll. This means end consumers will only have to deal with 1 dll instead of 2.
For augments sake lets say that the 3rd party dll is nLog. How do I deal with cases where the consumer of the merged dll already has NLog as a reference in their project?
Ideally what I would like to be able to do is change NLog namespace within my project to "XyzNLog", meaning that the user wouldn't need to do any aliasing... Any idea how I might do this?
Now I know I can add aliases to my project for NLog so that I have to refer to it as XyzNLog, but I want the same to carry over to consumers of the merged dll so that there is never a conflict.
UPDATE - Solution
http://blog.mattbrailsford.com/2010/12/10/avoiding-dependency-conflicts-using-ilmerge/
Bingo! So by using ILMerge, it becomes
possible to merge the third-party
libraries DLLs in with the Providers
own DLL, meaning we will only have one
DLL to deploy. But that’s not all, we
can actually go one step further, and
tell ILMerge to internalize all
dependencies. What this does it
converts all the third party classes
to be declared as internal, meaning
they can only be used from within the
final DLL. Woo hoo! problem solved =)
Given this the problem where the consumer of my dll could also have NLog goes away... as my referenced NLog shifts to being all internal! This is exactly what I want.
Does anyone have any feedback or thoughts on this?
I agree with Hans, I would strongly suggest releasing with registering the DLLs separately.
Otherwise, you could be in DLL hell which would drive your consumers away.
You could then devise some clever deploy methods to detect if the DLL is already registered, etc.
I have to agree with #Hans Passant (and here's some info about the oft-discussed DLL hell), but since you've asked the question, I'll try to answer it.
You can bundle the third-party DLL as a resource. Please see this question for details.
As far as your other questions, I'd just expose the relevant classes from a third-party DLL under your own namespace, and maybe use extension methods to provide whatever additional functionality you want.
For instance, you can provide access to NLog's Log() method using a static method in your class, say XyzNLog.Logger.Log(), taking care of initialization, and whatever else internally, inside your code (static constructor or whatever else you fancy up).
Since you load the NLog assembly using the method above, you'll be the only one having access to the embedded NLog assembly directly and the user won't be able to access it. Now, you don't get the benefit of having all classes autoexposed from NLog, you still have to expose them manually in this case.
EDIT: Another approach would be to try to use ILMerge with /internalize flag as described here. You may not be able to completely resolve the issue, but look at this article to see if you can avoid the pitfalls the author described. Spoiler alert: it's not all peaches'n'cream on this one either, but it may work, with enough extra effort.
My .Net C# appliation is referencing a strong named dll,and my requiremnet is to redirect the application to use another dll with a different name ( version and key are same for both dlls), how can i achive this without recompiling the application.
Here is the offical doc on this: Redirecting Assembly Versions (check out the "Specifying Assembly Binding in Configuration Files" section, this is the most easy to do)
Reflection might be a solution.
At the point you know what dll you want to use pull in the dll by reflection.
If both dlls derive from the same interface then the rest of the code can be very generic no matter the dll you use.
You can't as far as i know. That's the beauty of it, strong named assemblies are produced with a signature, precisely to avoid what you're trying to do.
After all it wouldn't have much security if you could just substitute a DLL from another one and having the new DLL methods do whatever you want under the original caller context would it?
I am creating an app with several DLLs and thought I could just call Assembly.GetPublicKey() at run time and see if the DLLs were signed by me. However, I now see there's a SetPublicKey
method on the Assembly. Doesn't it make it easy for anyone to spoof my DLLs?
Or am I checking the signature of the DLLs the wrong way?
Update: I have a plugin architecture and I am just trying to prevent someone hijacking my app by writing their own DLL.
Is your entire application in .NET? When you compile, any assembly that references another should require the assembly be properly signed, and .NET should be able to handle this, and it should be transparent to you. You should not have to check assemblies yourself.
http://msdn.microsoft.com/en-us/library/ab4eace3.aspx
Not probably the suggested route but what I do for my DLL's is create a class and pass a private key to it to activate it.
var secureClass = new MyDLL.SecureClass("Password")
then on any method inside SecureClass i call the following before I put any code:
if IsActivated() = false then
Alert_Not_Active()
Return False
End If
Maybe there is better options but this works perfect for me. Make sure to use an application like {Smart Assembly} to protect your code from Reflection if it's extremely important coding
I have got a dll placed in a shared folder over development server. Is there any way to use that dll without adding reference in my application and without installing the same in GAC.
Thanks in advance.
Assembly asm = Assembly.LoadFrom(path);
See MSDN for late binding, reflection etc.
Small edit: A variable with the keyword "as" is asking for trouble. So "Assembly as" changed to "Assembly asm" should be safer.
You may want to look at the Managed Extensibility Framework or at Assembly.Load... in the base framework.
Why would you want to do this, though? You'd need to call any code within the Assembly via reflection (hence the suggestion that the MEF may be what you're really after).
Yes, it is possible...somehow. Have a look at the Assembly-Class. With it you can load assemblies from a file without knowing what you exactly load.
Using Assembly.LoadFrom would be the only way to have zero references, but you'd still need to share contracts.
What's the problem with adding a reference?
What are you going to do when someone wants to work on a laptop and the WiFi goes down?
Yes,
you can call Assembly.Load() and then make use of Reflection to call into the public interface (lowercase "interface" - what I mean is the methods, fields and properties) exposed by the assembbly.
But in order to do that you need to know what methods to call. It helps if you can be certain that the assembly includes classes that do conform to a known .NET interface.
This idea is the basis for "plug-in" architectures in many tools, where the tool loads any assembly in its "plugin" directory, instantiates classes, casts the result to an ISomething, and then invokes methods via that interface.
I also would read Suzanne Cook's .NET CLR Notes.
http://blogs.msdn.com/suzcook/default.aspx
If this assembly is in a shared folder, you may find that .NET security restrictions stop you working with classes in that assembly in quite the way you'd expect.
Rather than storing on a shared folder, you may want to consider checking in the assembly to your source code repository. (I've seen a "/lib" folder used to good effect for this). Then you can reference the assembly directly.
(There are also repository solutions such as Maven that can more properly control this. However, they don't play well with .NET, unfortunately.)