netdev - Re: [PATCH v2 1/5] lsm: Add hook unix_path

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Message-ID: <CAHC9VhQZ_J9316Us0squV_f-MjYXPcex34BnJ14vEBxS9Jyjbg@mail.gmail.com>
Date: Tue, 13 Jan 2026 18:30:37 -0500
From: Paul Moore <paul@...l-moore.com>
To: Justin Suess <utilityemal77@...il.com>
Cc: Günther Noack <gnoack3000@...il.com>, 
	Mickaël Salaün <mic@...ikod.net>, 
	James Morris <jmorris@...ei.org>, "Serge E . Hallyn" <serge@...lyn.com>, 
	linux-security-module@...r.kernel.org, Tingmao Wang <m@...wtm.org>, 
	Samasth Norway Ananda <samasth.norway.ananda@...cle.com>, Matthieu Buffet <matthieu@...fet.re>, 
	Mikhail Ivanov <ivanov.mikhail1@...wei-partners.com>, konstantin.meskhidze@...wei.com, 
	Demi Marie Obenour <demiobenour@...il.com>, Alyssa Ross <hi@...ssa.is>, Jann Horn <jannh@...gle.com>, 
	Tahera Fahimi <fahimitahera@...il.com>, Simon Horman <horms@...nel.org>, netdev@...r.kernel.org, 
	Alexander Viro <viro@...iv.linux.org.uk>, Christian Brauner <brauner@...nel.org>
Subject: Re: [PATCH v2 1/5] lsm: Add hook unix_path_connect

On Tue, Jan 13, 2026 at 5:51 PM Paul Moore <paul@...l-moore.com> wrote:
> On Sat, Jan 10, 2026 at 11:45 AM Justin Suess <utilityemal77@...il.com> wrote:
> > On 1/10/26 09:32, Günther Noack wrote:
> > > From: Justin Suess <utilityemal77@...il.com>
> > >
> > > Adds an LSM hook unix_path_connect.
> > >
> > > This hook is called to check the path of a named unix socket before a
> > > connection is initiated.
> > >
> > > Cc: Günther Noack <gnoack3000@...il.com>
> > > Signed-off-by: Justin Suess <utilityemal77@...il.com>
> > > ---
> > >  include/linux/lsm_hook_defs.h |  4 ++++
> > >  include/linux/security.h      | 11 +++++++++++
> > >  net/unix/af_unix.c            |  9 +++++++++
> > >  security/security.c           | 20 ++++++++++++++++++++
> > >  4 files changed, 44 insertions(+)
>
> ...
>
> > > +#if defined(CONFIG_SECURITY_NETWORK) && defined(CONFIG_SECURITY_PATH)
> > > +/*
> > > + * security_unix_path_connect() - Check if a named AF_UNIX socket can connect
> > > + * @path: path of the socket being connected to
> > > + * @type: type of the socket
> > > + * @flags: flags associated with the socket
> > > + *
> > > + * This hook is called to check permissions before connecting to a named
> > > + * AF_UNIX socket.
> > > + *
> > > + * Return: Returns 0 if permission is granted.
> > > + */
> > > +int security_unix_path_connect(const struct path *path, int type, int flags)
> > > +{
> > > +     return call_int_hook(unix_path_connect, path, type, flags);
> > > +}
> > > +EXPORT_SYMBOL(security_unix_path_connect);
>
> ...
>
> > I'm considering renaming this hook to unix_socket_path_lookup, since as Günther
> > pointed out this hook is not just hit on connect, but also on sendmsg.
>
> I'm not bothered too much ...

I forgot to add that I know you're likely going to do another revision
to this patchset to rename the hook, but I would suggest waiting until
the AppArmor folks have had a chance to look at the hook.  I want to
make sure the new hook is reasonable and suitably generic for a
path-based LSM, and while I suspect it is, having another set of
path-based LSM eyes review the hook would be a very good thing.

-- 
paul-moore.com