Re: [PATCH v2 1/3] LSM: Add new hook for generic node initialization

From: Paul Moore <paul@paul-moore.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>,
	selinux@vger.kernel.org, Stephen Smalley <sds@tycho.nsa.gov>,
	linux-security-module@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>,
	linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org
Subject: Re: [PATCH v2 1/3] LSM: Add new hook for generic node initialization
Date: Thu, 10 Jan 2019 20:57:17 -0500	[thread overview]
Message-ID: <CAHC9VhS6pGycbT1GET5CHjxgYCDu1KCrcPtcF0n==1oH15kAVA@mail.gmail.com> (raw)
In-Reply-To: <cbe734fb-cd91-57a8-0de5-f4f0f8a1a2cd@schaufler-ca.com>

On Wed, Jan 9, 2019 at 12:08 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 1/9/2019 8:28 AM, Ondrej Mosnacek wrote:
> > This patch introduces a new security hook that is intended for
> > initializing the security data for newly created pseudo filesystem
> > objects (such as kernfs nodes) that provide a way of storing a
> > non-default security context, but need to operate independently from
> > mounts.
> >
> > The main motivation is to allow kernfs nodes to inherit the context of
> > the parent under SELinux, similar to the behavior of
> > security_inode_init_security(). Other LSMs may implement their own logic
> > for handling the creation of new nodes.
> >
> > Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> > ---
> >  include/linux/lsm_hooks.h | 30 ++++++++++++++++++++++++++++++
> >  include/linux/security.h  | 14 ++++++++++++++
> >  security/security.c       | 10 ++++++++++
> >  3 files changed, 54 insertions(+)
> >
> > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> > index aaeb7fa24dc4..3a2399d7721f 100644
> > --- a/include/linux/lsm_hooks.h
> > +++ b/include/linux/lsm_hooks.h
> > @@ -429,6 +429,31 @@
> >   *   to abort the copy up. Note that the caller is responsible for reading
> >   *   and writing the xattrs as this hook is merely a filter.
> >   *
> > + * Security hooks for special file-like objects
> > + *
> > + * @object_init_security:
>
> I don't like the name. There are too many things that are "objects"
> for this to be meaningful. I also dislike seeing names like
> security_object_init_security. How about init_from_parent? If there's
> never a chance that it will be used anywhere but with kernfs, it could
> be kernfs_node_init. The existing set of hook names are sufficiently
> confusing without adding to the mystery.

I like the naming similarity with inode_init_security(), that seems
helpful.  Although I somewhat understand you concern about the generic
"object".  Could you live with kernfs_init_security()?  If another fs
adopts it, we could always changing the name later if needed.

-- 
paul moore
www.paul-moore.com