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Date:   Wed, 9 Feb 2022 09:43:43 +0300
From:   Cyrill Gorcunov <gorcunov@gmail.com>
To:     "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc:     "Lutomirski, Andy" <luto@kernel.org>,
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Subject: Re: [PATCH 00/35] Shadow stacks for userspace
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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.