[Mono-dev] Why does Mono's CoreCLR blocks internal method reflection from transparent code ?

[Rolf Bjarne Kvinge]

I believe you're asking the wrong question: why should CoreCLR allow
transparent code to call internal methods? It doesn't matter if
they're transparent or not, there's a reason a method is internal and
you can make the object confused if internal methods are called
directly.

Rolf

On Sun, Mar 24, 2013 at 7:08 PM, nelson <nelson.cabral at gmail.com> wrote:
> I'm checking that code, at
> https://github.com/mono/mono/blob/master/mono/metadata/security-core-clr.c.
>
> If to "ensure that the specified method can be used with reflection since
> Transparent code cannot call Critical methods" is fine with me, why does
> CoreCLR also prevents transparent code to call internal transparent methods
> or properties through reflection ?
>
> I'm not a security expert, and am curious to know if removing this check
> affects mono clr's security.
> I'm comparing the code below to this page about CoreCLR :
> http://www.mono-project.com/Moonlight2CoreCLR .
>
> Details :
>
> /*
>  * mono_security_core_clr_ensure_reflection_access_method:
>  *
>  *  Ensure that the specified method can be used with reflection since
>  *  Transparent code cannot call Critical methods and can only call them
>  *  if they are visible from it's point of view.
>  *
>  *  A MethodAccessException is thrown if the field is cannot be accessed.
>  */
> void
> mono_security_core_clr_ensure_reflection_access_method (MonoMethod *method)
> {
>     MonoMethod *caller = get_reflection_caller ();
>     /* CoreCLR restrictions applies to Transparent code/caller */
>     if (mono_security_core_clr_method_level (caller, TRUE) !=
> MONO_SECURITY_CORE_CLR_TRANSPARENT)
>         return;
>
>     if (mono_security_core_clr_get_options () &
> MONO_SECURITY_CORE_CLR_OPTIONS_RELAX_REFLECTION) {
>         if (!mono_security_core_clr_is_platform_image
> (method->klass->image))
>             return;
>     }
>
>     /* Transparent code cannot invoke, even using reflection, Critical code
> */
>     if (mono_security_core_clr_method_level (method, TRUE) ==
> MONO_SECURITY_CORE_CLR_CRITICAL) {
>         mono_raise_exception (get_method_access_exception (
>             "Transparent method %s cannot invoke Critical method %s.",
>             caller, method));
>     }
>
>     /* also it cannot invoke a method that is not visible from it's (caller)
> point of view */
>     if (!check_method_access (caller, method)) {
>         mono_raise_exception (get_method_access_exception (
>             "Transparent method %s cannot invoke private/internal method
> %s.",
>             caller, method));
>     }
> }
>
> Hope someone can answer me...
>
>
>
> --
> View this message in context: http://mono.1490590.n4.nabble.com/Why-does-Mono-s-CoreCLR-blocks-internal-method-reflection-from-transparent-code-tp4659140.html
> Sent from the Mono - Dev mailing list archive at Nabble.com.
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