Code Access Security

[John Smith]

I don't think I have understood the concept of Code Access Security in
Dotnet fully.
1) I simply can't appreciate the method - *Permission.Assert that asserts
the 'right' and bypasses the security policy !! Wouldn't this make the
security policy redundant? (as any untrusted code can simply assert the
right and continue!!)

2) I have tried to change the Permission Set for All_Code code group to use
'Everything' but my code (which is a very basic dotnet windows application)
doesn't run. I have to revert to 'Full Trust'. I would imagine 'Full Trust'
to be same as granting unrestricted access to all protectable resources
(which is basically 'Everything') but it doesn't seem so.

3) Also I have found that any changes made to Enterprise or Machine level
policies don't take effect, I have to always change the User Level one. But
the documentation says the final Permission Set is an 'Intersection' of all
three levels !!

I am sure I am missing something... anybody shed some light on the issues ?

[Michael Giagnocavo [MVP]]

> 1) I simply can't appreciate the method - *Permission.Assert that asserts

the 'right' and bypasses the security policy !! Wouldn't this make the
security policy redundant? (as any untrusted code can simply assert the
right and continue!!)

If the code doesn't have the permission, it can't assert it. Assert is used
in a trusted library that's going to perform a high-permission action (for
instance, System.IO.File calls native code somewhere to actually touch the
disk. BUT, it asserts before doing so, so your code only needs FileIO
permissions).

-mike
MVP

[Michael Giagnocavo [MVP]]

> 1) I simply can't appreciate the method - *Permission.Assert that asserts

the 'right' and bypasses the security policy !! Wouldn't this make the
security policy redundant? (as any untrusted code can simply assert the
right and continue!!)

If the code doesn't have the permission, it can't assert it. Assert is used
in a trusted library that's going to perform a high-permission action (for
instance, System.IO.File calls native code somewhere to actually touch the
disk. BUT, it asserts before doing so, so your code only needs FileIO
permissions).

-mike
MVP