[PATCH] devpts: Make ptmx be owned by the userns owner instead of userns-local 0

[Alexander Larsson]

On sön, 2016-03-13 at 22:06 -0700, Andy Lutomirski wrote:
> We used to have ptmx be owned by the inner uid and gid 0.  Change
> this: if the owner and group are both mapped but are not both 0,
> then use the owner instead.
> 
> For container-style namespaces (LXC, etc), this should have no
> effect -- UID 0 is will either be the owner or will be unmapped.
> 
> The important behavior change is for sandboxes: many sandboxes
> intentionally do not create an inner uid 0.  Without this patch,
> mounting devpts in such a sandbox is awkward.  With this patch, it
> will just work and ptmx will be owned by the namespace owner.
> 
> Cc: Alexander Larsson <alexl at redhat.com>
> Cc: mclasen at redhat.com
> Cc: "Eric W. Biederman" <ebiederm at xmission.com>
> Cc: Linux Containers <containers at lists.linux-foundation.org>
> Signed-off-by: Andy Lutomirski <luto at kernel.org>

Tested-by: Alexander Larsson <alexl at redhat.com>

Seems to work fine for me! Thanks!

-- 
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 Alexander Larsson                                            Red Hat, Inc 
       alexl at redhat.com            alexander.larsson at gmail.com 
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