CCing linux-api and stable to give them a chance to confirm that
changing proc symlink content is OK.


On 15/10/2021 11:10, Christian Brauner wrote:

On Wed, Oct 13, 2021 at 05:47:53PM +0200, Mickaël Salaün wrote:

quoted

On 12/10/2021 23:09, Paul Moore wrote:

quoted

On Tue, Oct 12, 2021 at 4:38 PM Ondrej Mosnacek [off-list ref] wrote:

quoted

On Tue, Oct 12, 2021 at 8:12 PM Paul Moore [off-list ref] wrote:

quoted

On Tue, Oct 12, 2021 at 6:38 AM Christian Brauner
[off-list ref] wrote:

quoted

On Mon, Oct 11, 2021 at 04:38:55PM +0200, Mickaël Salaün wrote:

quoted

On 11/10/2021 15:37, Christian Brauner wrote:

quoted

From: Christian Brauner <redacted>

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