Re: Apply security permission in class library, fail to call it ou

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: Branimir Giurov (branimir_at_nospam.com)
Date: 08/06/04 

Date: Fri, 6 Aug 2004 15:52:54 +0300

It depends -

if there is a permission denied from the OS (like file permission) it should
throw an exception as well. You can do something else - try to do a security
demand in the class library before accessing a resource. Before the demand,
write into the debuger or the trace, then do the same after the deman. The
security demand will wall the call stack and make sure that the callers have
the the same permissions as well as the one you're asking for. For example:

Trace.WriteLine("before demand permission to ...");
FileIOPermission fp = new FileIOPermission(FileIOPermissionAccess.Read,
"c:\\test.txt");
fp.Demand();
Trace.WriteLine("after demand permission to ...");

You should do that if you can't debug the source with VS. By doing this, you
can intercept where the exception comes from. The other possible solution is
to compile in a Debug mode and catch the permission at app level. Then log
the stack trace and the message. By looking at the stack trace, you'll see
in which method the exception was thrown originally.

Let me know how it goes. :)

Branimir 

-- 
Branimir Giurov
MCSD.NET, MCDBA
www.sofiadev.org
"Chua Wen Ching" <chua_wen_ching@nospam.hotmail.com> wrote in message
news:CC449F61-193B-459B-A3F9-186BF15520C6@microsoft.com...
> I had a tester app with a button. Inside the button click function, it
will
> call the class library with security permission.
>
> It means, when i run the app no problem, just when i click on the button,
i
> receive the security problem.
>
> Thanks for the previous tip. Do i need to do anything extra on the tester
> app? Like coding attributes or doing something to allow me? Or is more to
> permission on windows side?
>
> Thanks again.
>
> "Branimir Giurov" wrote:
>
> > Hi there,
> >
> > if the exception is being thrown right after you start the app, there
should
> > be a problem with the requested permissions (The RequestMinimum for
example
> > or some more like it in the app).
> >
> > Before the CLR starts the execution of the assembly, it will check if
all of
> > the requested permissions are being granted. That means that based on
the
> > evidences for the assembly's origin (zone it is being started from,
strong
> > name, digital signature, etc.) it will be assigned to a predefined code
> > group.
> > If at that point, the CLR can't apply the securty request, an exception
will
> > be trown(which might be a SecurityException or PolicyException -
depending
> > on the case).
> >
> > Otherwise, if the exception is being thrown after the app starts, you
should
> > try to find where the exception is being trowned - there should be a
problem
> > with some resource (something else than those with RequestMinimum or an
> > action performed to a resource being explicitly refused or optional -
like
> > the FileIO or the UnmanagedCode) not being allowed by the CLR's Security
> > system to your app. The problem might be the restricted user's account
under
> > you're trying to start the app or something else - like starting it from
a
> > network location (which is not being detected as local intranet) - in
this
> > case the CAS (code access security) just restricts the permissions to
the
> > app.
> >
> > Hope that helps,
> > Branimir
> >
> > -- 
> > Branimir Giurov
> > MCSD.NET, MCDBA
> > www.sofiadev.org
> >
> >
> >
> > "Chua Wen Ching" <chua_wen_ching@nospam.hotmail.com> wrote in message
> > news:E70BE981-1067-4151-B3FD-BDB6AD48C850@microsoft.com...
> > > Hi there,
> > >
> > > I had applied this security permissions in my class library based on
fxcop
> > > standards.
> > >
> > > Before namespace:
> > >
> > > using System.Runtime.InteropServices;
> > > using System.Security.Permissions;
> > >
> > > [assembly:IsolatedStorageFilePermission(SecurityAction.RequestMinimum,
> > > UserQuota=1048576)]
> > > [assembly:SecurityPermission(SecurityAction.RequestRefuse,
> > > UnmanagedCode=true)]
> > > [assembly:FileIOPermission(SecurityAction.RequestOptional,
> > Unrestricted=true)]
> > >
> > > In AssemblyInfo.cs
> > >
> > > [assembly: AssemblyKeyFile("../../snkey.snk")]
> > >
> > > But when my windows app try to all the function during run time, it
just
> > > fails.
> > >
> > > The errors:
> > >
> > > An unhandled exception of type 'System.Security.SecurityException'
occured
> > > in Tester.exe
> > >
> > > Any tips?
> > >
> > > Thanks.
> > > -- 
> > > Regards,
> > > Chua Wen Ching :)
> >
> >
> >

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