linux-kernel - Re: [RFC PATCH 0/2] selinux,anon_inodes: Use a separate SELinux class for each type of anon inode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 22 Apr 2021 13:39:39 +0200
From:   Ondrej Mosnacek <omosnace@...hat.com>
To:     Paul Moore <paul@...l-moore.com>
Cc:     SElinux list <selinux@...r.kernel.org>,
        Linux Security Module list 
        <linux-security-module@...r.kernel.org>, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org,
        Linux kernel mailing list <linux-kernel@...r.kernel.org>,
        Lokesh Gidra <lokeshgidra@...gle.com>,
        Stephen Smalley <stephen.smalley.work@...il.com>
Subject: Re: [RFC PATCH 0/2] selinux,anon_inodes: Use a separate SELinux class
 for each type of anon inode

On Wed, Apr 21, 2021 at 10:38 PM Paul Moore <paul@...l-moore.com> wrote:
> On Wed, Apr 21, 2021 at 1:14 PM Ondrej Mosnacek <omosnace@...hat.com> wrote:
> >
> > This series aims to correct a design flaw in the original anon_inode
> > SELinux support that would make it hard to write policies for anonymous
> > inodes once more types of them are supported (currently only userfaultfd
> > inodes are). A more detailed rationale is provided in the second patch.
> >
> > The first patch extends the anon_inode_getfd_secure() function to accept
> > an additional numeric identifier that represents the type of the
> > anonymous inode being created, which is passed to the LSMs via
> > security_inode_init_security_anon().
> >
> > The second patch then introduces a new SELinux policy capability that
> > allow policies to opt-in to have a separate class used for each type of
> > anon inode. That means that the "old way" will still
>
> ... will what? :)

Whoops, I thought I had gone over all the text enough times, but
apparently not :) It should have said something along the lines of:

...will still work and will be used by default.

>
> I think it would be a very good idea if you could provide some
> concrete examples of actual policy problems encountered using the
> current approach.  I haven't looked at these patches very seriously
> yet, but my initial reaction is not "oh yes, we definitely need this".

An example is provided in patch 2. It is a generalized problem that we
would eventually run into in Fedora policy (at least) with the
unconfined_domain_type attribute and so far only hypothetical future
types of anon inodes.

-- 
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.