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Date:   Tue, 8 Feb 2022 12:29:18 +0300
From:   Cyrill Gorcunov <gorcunov@gmail.com>
To:     Mike Rapoport <rppt@kernel.org>
Cc:     Dave Hansen <dave.hansen@intel.com>,
        Adrian Reber <adrian@lisas.de>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>, x86@kernel.org,
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        Arnd Bergmann <arnd@arndb.de>,
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        Balbir Singh <bsingharora@gmail.com>,
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        Dave Hansen <dave.hansen@linux.intel.com>,
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        Dmitry Safonov <0x7f454c46@gmail.com>
Subject: Re: [PATCH 00/35] Shadow stacks for userspace
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On Tue, Feb 08, 2022 at 11:16:51AM +0200, Mike Rapoport wrote:
>  
> > Any thoughts on how you would _like_ to see this resolved?
> 
> Ideally, CRIU will need a knob that will tell the kernel/CET machinery
> where the next RET will jump, along the lines of
> restore_signal_shadow_stack() AFAIU.
> 
> But such a knob will immediately reduce the security value of the entire
> thing, and I don't have good ideas how to deal with it :(

Probably a kind of latch in the task_struct which would trigger off once
returt to a different address happened, thus we would be able to jump inside
paratite code. Of course such trigger should be available under proper
capability only.