Help! Debugger reporting System.IO.FIleLoadException.

[Ken Varn]

I am trying to remote debug a C# application but the debugger is reporting
the following exception:

An unhandled exception of type 'System.IO.FileLoadException' occurred in
Unknown Module.
Additional information: Unverifiable assembly 'FrameGrabber' failed policy
check.

The FrameGrabber assembly is a C++ managed DLL.

I cannot get a stack trace on the exception in the debugger.
I have seen this occur when a C++ managed DLL cannot locate an unmanaged
library
dependency.

The weird thing is that I do not get this exception when I run my
application without the debugger.

I have used the "Depends" tool to check the DLL and found no missing DLLs.
Can someone help me out on what I can
do to locate the cause of this exception?

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.
va***@diebold.com
-----------------------------------

[Ken Varn]

Your explanation makes sense, however the twist is that I able to remotely
debug my managed C++ application that uses the same DLL and it does not
produce this exception. What's with that?

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.
va***@diebold.com
-----------------------------------
"Mark Pearce" <ev**@bay.com> wrote in message
news:Od**************@TK2MSFTNGP11.phx.gbl...

Hi Ken,

If you're running (and remote debugging) your app from a local network
share, then I suspect that you're running into a permissions issue. Programs that run on the CLR use something called code access security (CAS), which
assigns trust based upon evidence it can gather from the code itself. This
evidence is then compared against the security policy, and a permission
grant is generated.

Part of the evidence used is the security zone where the code is located.
When you run the code from your local machine, this will be the MyComputer
zone, but when you run it off from a server (or even a server share mapped
to a drive on your machine), it will be LocalIntranet. By
default, any code that is run from the MyComputer zone will get a permission set of FullTrust (un-restricted permission to do anything it pleases).
However, there is a more restrictive policy placed on LocalIntranet
assemblies.

You probably can't get an exception stack trace because it's not your app
that's throwing the exception, it's the CLR.

A temporary method of solving this issue is to simply give the LocalIntranet zone more trust. This can be done in the .NET Framework Configuration
control panel applet. A permanent solution is to modify your security policy to give FullTrust to all assemblies signed with your key.

HTH,

Mark
--
Author of "Comprehensive VB .NET Debugging"
http://www.apress.com/book/bookDisplay.html?bID=128
"Ken Varn" <va***@diebold.com> wrote in message
news:uK**************@TK2MSFTNGP12.phx.gbl...
I am trying to remote debug a C# application but the debugger is reporting
the following exception:

An unhandled exception of type 'System.IO.FileLoadException' occurred in
Unknown Module.
Additional information: Unverifiable assembly 'FrameGrabber' failed policy
check.

The FrameGrabber assembly is a C++ managed DLL.

I cannot get a stack trace on the exception in the debugger.
I have seen this occur when a C++ managed DLL cannot locate an unmanaged
library
dependency.

The weird thing is that I do not get this exception when I run my
application without the debugger.

I have used the "Depends" tool to check the DLL and found no missing DLLs.
Can someone help me out on what I can
do to locate the cause of this exception?

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.
va***@diebold.com
-----------------------------------

[Mark Pearce]

Hi Ken,

Sorry, but I know absolutely nothing about managed C++ and how permissions
work in that environment. Are you doing that remote debugging in the same
way, i.e. by launching the remote app from within Visual Studio? Or are you
launching it directly on the remote pc and attaching a debugger, in which
case the permissions issue doesn't apply?

Regards,

Mark
--
Author of "Comprehensive VB .NET Debugging"
http://www.apress.com/book/bookDisplay.html?bID=128
"Ken Varn" <va***@diebold.com> wrote in message
news:#E**************@TK2MSFTNGP12.phx.gbl...
Your explanation makes sense, however the twist is that I able to remotely
debug my managed C++ application that uses the same DLL and it does not
produce this exception. What's with that?

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.
va***@diebold.com
-----------------------------------
"Mark Pearce" <ev**@bay.com> wrote in message
news:Od**************@TK2MSFTNGP11.phx.gbl...

Hi Ken,

If you're running (and remote debugging) your app from a local network
share, then I suspect that you're running into a permissions issue. Programs that run on the CLR use something called code access security (CAS), which
assigns trust based upon evidence it can gather from the code itself. This
evidence is then compared against the security policy, and a permission
grant is generated.

Part of the evidence used is the security zone where the code is located.
When you run the code from your local machine, this will be the MyComputer
zone, but when you run it off from a server (or even a server share mapped
to a drive on your machine), it will be LocalIntranet. By
default, any code that is run from the MyComputer zone will get a permission set of FullTrust (un-restricted permission to do anything it pleases).
However, there is a more restrictive policy placed on LocalIntranet
assemblies.

You probably can't get an exception stack trace because it's not your app
that's throwing the exception, it's the CLR.

A temporary method of solving this issue is to simply give the LocalIntranet zone more trust. This can be done in the .NET Framework Configuration
control panel applet. A permanent solution is to modify your security policy to give FullTrust to all assemblies signed with your key.

HTH,

Mark
--
Author of "Comprehensive VB .NET Debugging"
http://www.apress.com/book/bookDisplay.html?bID=128
"Ken Varn" <va***@diebold.com> wrote in message
news:uK**************@TK2MSFTNGP12.phx.gbl...
I am trying to remote debug a C# application but the debugger is reporting
the following exception:

An unhandled exception of type 'System.IO.FileLoadException' occurred in
Unknown Module.
Additional information: Unverifiable assembly 'FrameGrabber' failed policy
check.

The FrameGrabber assembly is a C++ managed DLL.

I cannot get a stack trace on the exception in the debugger.
I have seen this occur when a C++ managed DLL cannot locate an unmanaged
library
dependency.

The weird thing is that I do not get this exception when I run my
application without the debugger.

I have used the "Depends" tool to check the DLL and found no missing DLLs.
Can someone help me out on what I can
do to locate the cause of this exception?

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.
va***@diebold.com
-----------------------------------

[Ken Varn]

I tried to run CASPOL and disabled all .NET security and that seemed to fix
the problem. It seems strange however that the security is so tight for C#,
but not for C++. I have had a whole slew of issues regarding remote
debugging. A lot of other security restrictions are a big pain and I wish
there was an option to bypass all of them with some sort of registry setting
or something.

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.
va***@diebold.com
-----------------------------------
"Mark Pearce" <ev**@bay.com> wrote in message
news:eE****************@TK2MSFTNGP11.phx.gbl...

Hi Ken,

Sorry, but I know absolutely nothing about managed C++ and how permissions
work in that environment. Are you doing that remote debugging in the same
way, i.e. by launching the remote app from within Visual Studio? Or are you launching it directly on the remote pc and attaching a debugger, in which
case the permissions issue doesn't apply?

Regards,

Mark
--
Author of "Comprehensive VB .NET Debugging"
http://www.apress.com/book/bookDisplay.html?bID=128
"Ken Varn" <va***@diebold.com> wrote in message
news:#E**************@TK2MSFTNGP12.phx.gbl...
Your explanation makes sense, however the twist is that I able to remotely
debug my managed C++ application that uses the same DLL and it does not
produce this exception. What's with that?

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.
va***@diebold.com
-----------------------------------
"Mark Pearce" <ev**@bay.com> wrote in message
news:Od**************@TK2MSFTNGP11.phx.gbl...

Hi Ken,

If you're running (and remote debugging) your app from a local network
share, then I suspect that you're running into a permissions issue.

Programs

that run on the CLR use something called code access security (CAS), which assigns trust based upon evidence it can gather from the code itself. This evidence is then compared against the security policy, and a permission
grant is generated.

Part of the evidence used is the security zone where the code is located. When you run the code from your local machine, this will be the MyComputer zone, but when you run it off from a server (or even a server share mapped to a drive on your machine), it will be LocalIntranet. By
default, any code that is run from the MyComputer zone will get a

permission

set of FullTrust (un-restricted permission to do anything it pleases).
However, there is a more restrictive policy placed on LocalIntranet
assemblies.

You probably can't get an exception stack trace because it's not your app that's throwing the exception, it's the CLR.

A temporary method of solving this issue is to simply give the

LocalIntranet

zone more trust. This can be done in the .NET Framework Configuration
control panel applet. A permanent solution is to modify your security

policy

to give FullTrust to all assemblies signed with your key.

HTH,

Mark
--
Author of "Comprehensive VB .NET Debugging"
http://www.apress.com/book/bookDisplay.html?bID=128
"Ken Varn" <va***@diebold.com> wrote in message
news:uK**************@TK2MSFTNGP12.phx.gbl...
I am trying to remote debug a C# application but the debugger is reporting the following exception:

An unhandled exception of type 'System.IO.FileLoadException' occurred in
Unknown Module.
Additional information: Unverifiable assembly 'FrameGrabber' failed policy check.

The FrameGrabber assembly is a C++ managed DLL.

I cannot get a stack trace on the exception in the debugger.
I have seen this occur when a C++ managed DLL cannot locate an unmanaged
library
dependency.

The weird thing is that I do not get this exception when I run my
application without the debugger.

I have used the "Depends" tool to check the DLL and found no missing DLLs. Can someone help me out on what I can
do to locate the cause of this exception?

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.
va***@diebold.com
-----------------------------------