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From:   Jann Horn <jannh@google.com>
Date:   Mon, 25 May 2020 23:53:10 +0200
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Subject: Re: [PATCH] capabilities: Introduce CAP_RESTORE
To:     Adrian Reber <areber@redhat.com>
Cc:     Christian Brauner <christian.brauner@ubuntu.com>,
        Eric Biederman <ebiederm@xmission.com>,
        Pavel Emelyanov <ovzxemul@gmail.com>,
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        Kamil Yurtsever <kyurtsever@google.com>,
        Dirk Petersen <dipeit@gmail.com>,
        Christine Flood <chf@redhat.com>,
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On Fri, May 22, 2020 at 7:55 AM Adrian Reber <areber@redhat.com> wrote:
> This enables CRIU to checkpoint and restore a process as non-root.
>
> Over the last years CRIU upstream has been asked a couple of time if it
> is possible to checkpoint and restore a process as non-root. The answer
> usually was: 'almost'.
>
> The main blocker to restore a process was that selecting the PID of the
> restored process, which is necessary for CRIU, is guarded by CAP_SYS_ADMIN.

And if you were restoring the process into your own PID namespace, so
that you actually have a guarantee that this isn't going to blow up in
your face because one of your PIDs is allocated for a different
process, this part of the problem could be simplified.

I don't get why your users are fine with a "oh it kinda works 99% of
the time but sometimes it randomly doesn't and then you have to go
reboot or whatever" model.