[Mono-devel-list] RE: Code Access Security

[Benjamin Wootton]

Does anyone have any ideas on caspol and policy files?  Sebastien?

I've written CodeAccessSecurity.Demand, and need to move on to checking the
permissions assigned to stack frames:

	class test
	{
        public test()
        {
                foo();
        }

        public void foo()
        {
                FileIOPermission perm = new FileIOPermission(
PermissionState.None );
                perm.AddPathList( FileIOPermissionAccess.Write, "/tmp" );
                perm.Demand();
        }

        public static void Main()
        {
                test test = new test();
        }
}

Results in:

[root at geri MONO]# mono test.exe
About to make the demand!
Stack walk triggered....Walk: Demand
Walk: foo
Walk: .ctor
Walk: Main

Ben


> -----Original Message-----
> From: Benjamin Wootton [mailto:benjaminwootton at hotpop.com]
> Sent: Tuesday, January 20, 2004 8:28 PM
> To: 'spouliot at videotron.ca'
> Cc: 'Mono Development'
> Subject: RE: Code Access Security
> 
> Thanks for reply.  I'm now actively working on this, so dare say I will
> have lots of questions!
> 
> > > I've been implementing CodeAccessPermission.Demand.
> >
> > Without some runtime support this won't be easy to do, fix or test - I
> > know
> > as a tried a little ;)
> 
> I understand this all pretty well now, at least with imperative demands.
> I think I'm right in believing that declarative is harder.
> 
> Thanks for the explanation of policies etc.  Presumably CAS builds up the
> policy objects based on the information in the security config files:
> http://msdn.microsoft.com/library/default.asp?url=/library/en-
> us/cpguide/html/cpconsecurityconfigurationfiles.asp
> 
> I thought about starting to write a caspol to manipulate these policy
> files - I'm going some dummy data in the Policy classes to proceed.  Might
> as well build this in C#.  Also is there anything I should consider as to
> how the runtime should load these files, where they should be stored etc?
> There are also going to be interesting mappings between some MS permission
> concepts and those in Unix, presumably.
> 
> Finally, I also need to get a specification together of what exactly is
> required for CAS, and identify a point where I have the basic thing - and
> what constitutes the extensions.  I'd appreciate if I could hack this out
> with other members on the list...
> 
> Just wanted to check I'm on the right path.
> 
> Thanks
> Ben
> 
> 
> 
> 
> > E.g. (again incomplete)
> >
> > - The runtime is asked to load an assembly from
> > "http://www.go-mono.com/mono.dll";
> > - The runtime add an URL evidence for "http://www.go-mono.com/mono.dll"
> to
> > the assembly;
> > - The URL is then used to determine a SecurityZone (using
> > Zone.CreateFromURL
> > and re-using IE settings) which results in Internet;
> > - The PermissionSet for Internet can then be applied.
> > - If a method ask for a FileIOPermission then "CAS" will check if the
> > Internet permission set and refuse the operation.
> >
> > However if the mono.dll had a strongname (e.g. from Ximian) a Code
> Groups
> > could give the assembly a different set of permissions (like FullTrust).
> >
> > > For instance, we can define code groups and membership conditions in
> MS
> > > at the various levels, but how do the class libraries come into it?
> >
> > The "CAS engine" resides in the runtime for both performance and
> security
> > (isolation). But to make CAS extendable most of objects it works with
> are
> > implemented in managed code (in the class library).
> >
> > > Do they just reflect the policy as granted by the local system, so
> that
> > > we can work with this programmatically?  If this is the case, should
> > there
> > > be a PermissionSet in there somewhere representing the final grant
> set?
> >
> > That's the job of CAS to resolve it all ;) with the help from the class
> > library.
> > However it can be "a" final grant set - as every assembly can have
> > different
> > trust level inside an application domain
> >
> > > Any insights you can give into this would be very much appreciated!
> >
> > Have a look at bugzilla #52693
> > (http://bugzilla.ximian.com/show_bug.cgi?id=52693). This may be easier
> to
> > do
> > (but still a big step) and make it more easier to complete CAS
> afterward.
> >
> > BTW please keep your bugzilla entry
> > (http://bugzilla.ximian.com/show_bug.cgi?id=52606) updated with your
> work
> > (I
> > bookmarked it) or keep a blog about your work. It's the best way for
> > everyone (not just me) to see what's happening with CAS.
> >
> > Cya
> >
> > Sebastien Pouliot
> > Security Architect, Motus Technologies, http://www.motus.com
> > work: spouliot at motus.com
> > home: spouliot at videotron.ca
> > blog: http://pages.infinit.net/ctech/poupou.html
> >
> > -----Original Message-----
> > From: Ben [mailto:benjaminwootton at hotpop.com]
> > Sent: 12 janvier 2004 03:24
> > To: spouliot at videotron.ca
> > Subject: RE: Code Access Security
> >
> >
> > Sorry to contact you again.  I've been implementing
> > CodeAccessPermission.Demand.  I've been trying to work out this evening
> > how
> > System.Security.Policy, Evidence and Code Groups fit together.  I
> > understand
> > them in isolation, but I'm not sure how they fit into the rest of the
> > framework.
> >
> > For instance, we can define code groups and membership conditions in MS
> at
> > the various levels, but how do the class libraries come into it?  Do
> they
> > just reflect the policy as granted by the local system, so that we can
> > work
> > with this programmatically?  If this is the case, should there be a
> > PermissionSet in there somewhere representing the final grant set?
> >
> > Any insights you can give into this would be very much appreciated!
> >
> > Thanks
> > Ben
> >
> >
> >
> >
> >
> >
> >
> > From: Ben [mailto:benjaminwootton at hotpop.com]
> > Sent: Saturday, January 10, 2004 11:47 PM
> > To: 'spouliot at videotron.ca'
> > Subject: Code Access Security
> >
> > You posted to mono-devel last week about code access security.  I tried
> to
> > reply, but I'm not sure if it got through or not.
> >
> > I'm currently implementing parts of it.  I wanted to check we were not
> > duplicating any work, and also to see if you had any insights into how
> you
> > think this should be done.
> >
> > I'm currently making sure that permissions are correctly represented in
> > the
> > assembly metadata.  At the moment, Security permissions are just shown
> as
> > normal custom attributes.
> >
> > Ben