If only considering native components, it would be possible to extend camkes to 
support the notion of creating a shared data connector between 2 components 
that is defined by the address space of one end. It could currently be done 
with a custom connector type that assumed a maximum virtual address of the 
target component I believe, but adding specific support into camkes would 
likely allow specifying the elf program segments as something a shared 
connector could be connected to.

But because camkes is a static system where you can specify that the monitor 
component has read only access to the other native component.

For native Linux processes in a vm, you would probably need to trust modules 
inside the vmm and the Linux kernel to describe where the process's address 
space ends up in memory in order to scan it.
________________________________
From: Devel <[email protected]> on behalf of Heiser, Gernot (Data61, 
Kensington NSW) <[email protected]>
Sent: Saturday, 26 October 2019 2:07:23 PM
To: [email protected] <[email protected]>
Subject: Re: [seL4] releasing confidentiality

On 26 Oct 2019, at 08:00, Michael Neises <[email protected]> wrote:
>
> Hi,
>
> I know that seL4 provides confidentiality, which is described as a property 
> that "means that data cannot be read without permission." Given this wording, 
> I wonder if it is not possible to revoke those permissions in certain cases. 
> In particular, I would like for one camkes component to be able to perform 
> runtime measurements, such as heap analysis, on another component. Or even 
> better, I would like for a component to be able to perform runtime 
> measurements on a program running within the camkes linux vm. Is such a feat 
> possible?

Hi Michael

seL4’s confidentiality (and other security) enforcement means that the kernel 
guarantees that you can only access objects to which you have been given 
explicit permission (in the form of a capability). How those permissions are 
allocated is a matter of policy, the kernel doesn’t care, it only enforces.

In particular, it is totally possible in seL4 to give one component access to 
another component’s address space, that’s for the user-level policy framework 
to decide.

Whether the present CAmkES framework supports this is a different question, 
which I’ll leave to someone who’s more up to date with CAmkES details.

Gernot

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