Re: [Non-DoD Source] Re: [PATCH] fanotify, inotify, dnotify, security: add security hook for fs notifications

From: Amir Goldstein <amir73il@gmail.com>
To: Aaron Goidel <acgoide@tycho.nsa.gov>
Cc: Paul Moore <paul@paul-moore.com>,
	selinux@vger.kernel.org,
	LSM List <linux-security-module@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	David Howells <dhowells@redhat.com>, Jan Kara <jack@suse.cz>,
	James Morris <jmorris@namei.org>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [Non-DoD Source] Re: [PATCH] fanotify, inotify, dnotify, security: add security hook for fs notifications
Date: Fri, 9 Aug 2019 19:29:57 +0300	[thread overview]
Message-ID: <CAOQ4uxjfwhg4LaPhaDoSQqTviLbXT_-g+WNfQ5AahTK9d+h-Zw@mail.gmail.com> (raw)
In-Reply-To: <03ad3773-bea7-77de-0a1f-4bd6f41d3211@tycho.nsa.gov>

...
> >> First a suggestion, take it or leave it.
> >> The name of the hook _notify() seems misleading to me.
> >> naming the hook security_path_watch() seems much more
> >> appropriate and matching the name of the constants FILE__WATCH
> >> used by selinux.
> >
> > I guess I'm not too bothered by either name, Aaron?  FWIW, if I was
> > writing this hook, I would probably name it
> > security_fsnotify_path(...).
> >

Or even just security_fsnotify()

>
> While I'm not necessarily attached to the name, I feel as though
> "misleading" is too strong a word here.

Agree. It is not misleading, but I should note that you yourself
named the security class "watch", so why the inconsistency?

> Notify seems to be an
> appropriate enough term to me as every call to the hook, and thus all
> the logic to which the hook adds security, lives in the notify/ subtree.
>

Well, if nobody cares about the name, it's fine by me.

I wanted to point your attention to this proposal by David Howells:
https://lore.kernel.org/linux-fsdevel/155991706847.15579.4702772917586301113.stgit@warthog.procyon.org.uk/

His proposal adds new types of watches, for keyring changes,
mount changes, etc and he proposed security hooks for setting
new watches named "watch_XXX" and for posting notifications
called "post_notification". The latter was later rejected by
Stephen Smalley:
https://lore.kernel.org/linux-fsdevel/cd657aab-e11c-c0b1-2e36-dd796ca75b75@tycho.nsa.gov/
https://lore.kernel.org/linux-fsdevel/541e5cb3-142b-fe87-dff6-260b46d34f2d@tycho.nsa.gov/

Just to have a perspective why the hook name "notify_path" may end up
being a bit ambiguous down the road.

Thanks,
Amir.