Re: [PATCH 00/35] Shadow stacks for userspace

Cyrill Gorcunov
2022-02-09T06:43:50Z

On Wed, Feb 09, 2022 at 02:18:42AM +0000, Edgecombe, Rick P wrote:
...
>
> Still wrapping my head around the CRIU save and restore steps, but
> another general approach might be to give ptrace the ability to
> temporarily pause/resume/set CET enablement and SSP for a stopped
> thread. Then injected code doesn't need to jump through any hoops or
> possibly run into road blocks. I'm not sure how much this opens things
> up if the thread has to be stopped...
>
> Cyrill, could it fit into the CRIU pause and resume flow? What action
> causes the final resuming of execution of the restored process for
> checkpointing and for restore? Wondering if we could somehow make CET
> re-enable exactly then.
>
> And I guess this also needs a way to create shadow stack allocations at
> a specific address to match where they were in the dumped process. That
> is missing in this series.

Thanks Rick! This sounds like an option. I need a couple of days to refresh
my memory about criu internals. Let me CC a few current active criu developers
(CC list is already big enough though:), maybe this will speedup the procedure.