[PATCH] security/landlock: use square brackets around "landlock-ruleset"

[Christian Brauner]

On Wed, Oct 13, 2021 at 05:47:53PM +0200, Mickaël Salaün wrote:
> 
> On 12/10/2021 23:09, Paul Moore wrote:
> > On Tue, Oct 12, 2021 at 4:38 PM Ondrej Mosnacek <omosnace at redhat.com> wrote:
> >>
> >> On Tue, Oct 12, 2021 at 8:12 PM Paul Moore <paul at paul-moore.com> wrote:
> >>> On Tue, Oct 12, 2021 at 6:38 AM Christian Brauner
> >>> <christian.brauner at ubuntu.com> wrote:
> >>>> On Mon, Oct 11, 2021 at 04:38:55PM +0200, Mickaël Salaün wrote:
> >>>>> On 11/10/2021 15:37, Christian Brauner wrote:
> >>>>>> From: Christian Brauner <christian.brauner at ubuntu.com>
> >>>>>>
> >>>>>> Make the name of the anon inode fd "[landlock-ruleset]" instead of
> >>>>>> "landlock-ruleset". This is minor but most anon inode fds already
> >>>>>> carry square brackets around their name:
> >>>>>>
> >>>>>>     [eventfd]
> >>>>>>     [eventpoll]
> >>>>>>     [fanotify]
> >>>>>>     [fscontext]
> >>>>>>     [io_uring]
> >>>>>>     [pidfd]
> >>>>>>     [signalfd]
> >>>>>>     [timerfd]
> >>>>>>     [userfaultfd]
> >>>>>>
> >>>>>> For the sake of consistency lets do the same for the landlock-ruleset anon
> >>>>>> inode fd that comes with landlock. We did the same in
> >>>>>> 1cdc415f1083 ("uapi, fsopen: use square brackets around "fscontext" [ver #2]")
> >>>>>> for the new mount api.
> >>>>>
> >>>>> Before creating "landlock-ruleset" FD, I looked at other anonymous FD
> >>>>> and saw this kind of inconsistency. I don't get why we need to add extra
> >>>>> characters to names, those brackets seem useless. If it should be part
> >>>>
> >>>> Past inconsistency shouldn't justify future inconsistency. If you have a
> >>>> strong opinion about this for landlock I'm not going to push for it.
> >>>> Exchanging more than 2-3 email about something like this seems too much.
> >>>
> >>> [NOTE: adding the SELinux list as well as Chris (SELinux refrence
> >>> policy maintainer) and Petr (Fedora/RHEL SELinux)]
> >>>
> >>> Chris and Petr, do either of you currently have any policy that
> >>> references the "landlock-ruleset" anonymous inode?  In other words,
> >>> would adding the brackets around the name cause you any problems?
> >>
> >> AFAIU, the anon_inode transitions (the only mechanism where the "file
> >> name" would be exposed to the policy) are done only for inodes created
> >> by anon_inode_getfd_secure(), which is currently only used by
> >> userfaultfd. So you don't even need to ask that question; at this
> >> point it should be safe to change any of the names except
> >> "[userfaultfd]" as far as SELinux policy is concerned.
> > 
> > There is also io_uring if you look at selinux/next.
> > 
> > Regardless, thanks, I didn't check to see if landlock was using the
> > new anon inode interface, since both Mickaël and Christian were
> > concerned about breaking SELinux I had assumed they were using it :)
> > 
> 
> Ok, thanks Paul and Ondrej.
> 
> Such anonymous inode names seem to be only exposed to proc for now.
> Let's change this name then. I think it make sense to backport this
> patch down to 5.13 to fix all the inconsistencies.

Thank you. I do appreciate the point about this being annoying that we
have this inconsistency and it has bothered me too.

Christian