From: Jan Nieuwenhuizen <janneke@gnu.org>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: 44261@debbugs.gnu.org
Subject: bug#44261: running a daemon with userns in relocateble pack breaks
Date: Fri, 30 Oct 2020 23:05:08 +0100 [thread overview]
Message-ID: <877dr7s73f.fsf@gnu.org> (raw)
In-Reply-To: <871rhfxutl.fsf@gnu.org> ("Ludovic Courtès"'s message of "Fri, 30 Oct 2020 22:33:42 +0100")
Ludovic Courtès writes:
Hi!
> As discussed on IRC, my initial advice about MS_PRIVATE was misguided.
> The real issue is the “rm_rf (new_root);” call, which removes the root
> directory and thus leaves child processes (the daemon) with nothing.
Yes, I'm not entirely sure what I thought to see yesterday; anyway the
rm_rf (new_root) is indeed the thing that makes the daemon crash.
> The attached patch adds a test loosely based on yours and a fix for
> that. The fix (for the “userns” engine) is to make NEW_ROOT a tmpfs,
> such that upon completion, all we need to do is to unmount it and remove
> it; it lives on as the root file system of child processes.
>
> In the “fakechroot” case, we have to leave NEW_ROOT behind, which is not
> great but acceptable (it’s user-owned, #o700, and it’s under /tmp). The
> test only checks the “userns” engine.
Yes, I think this is acceptable.
> If you confirm that it works for you and looks reasonable, we can apply
> it.
Yes, this works. The test and also my reproducer now work fine.
Thanks a lot!
Janneke
--
Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond http://lilypond.org
Freelance IT http://JoyofSource.com | Avatar® http://AvatarAcademy.com
next prev parent reply other threads:[~2020-10-30 22:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 19:49 bug#44261: running a daemon with userns in relocateble pack breaks Jan Nieuwenhuizen
2020-10-27 20:09 ` Jan Nieuwenhuizen
2020-10-30 21:33 ` Ludovic Courtès
2020-10-30 22:05 ` Jan Nieuwenhuizen [this message]
2020-10-31 22:19 ` Ludovic Courtès
2020-11-01 6:07 ` Jan Nieuwenhuizen
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