Re: [PATCH v8 4/6] security: Allow all LSMs to provide xattrs for inode_init_security hook

From: Paul Moore <paul@paul-moore.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Roberto Sassu <roberto.sassu@huaweicloud.com>,
	mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com,
	zohar@linux.ibm.com, dmitry.kasatkin@gmail.com,
	jmorris@namei.org, serge@hallyn.com,
	stephen.smalley.work@gmail.com, eparis@parisplace.org,
	ocfs2-devel@oss.oracle.com, reiserfs-devel@vger.kernel.org,
	linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
	linux-kernel@vger.kernel.org, keescook@chromium.org,
	nicolas.bouchinet@clip-os.org,
	Roberto Sassu <roberto.sassu@huawei.com>
Subject: Re: [PATCH v8 4/6] security: Allow all LSMs to provide xattrs for inode_init_security hook
Date: Fri, 24 Mar 2023 10:17:09 -0400	[thread overview]
Message-ID: <CAHC9VhRxsY6B3dL7db4b8bfznEz6rK2qiaDug4Hc_ywvU3vB5A@mail.gmail.com> (raw)
In-Reply-To: <5d8d802a-7664-fdf0-52ef-5817634d870d@schaufler-ca.com>

On Thu, Mar 23, 2023 at 9:01 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 3/23/2023 5:09 PM, Paul Moore wrote:
> > On Tue, Mar 14, 2023 at 4:19 AM Roberto Sassu
> > <roberto.sassu@huaweicloud.com> wrote:

...

> >> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> >> index c2be66c669a..75a2f85b49d 100644
> >> --- a/include/linux/lsm_hooks.h
> >> +++ b/include/linux/lsm_hooks.h
> >> @@ -63,6 +63,7 @@ struct lsm_blob_sizes {
> >>         int     lbs_ipc;
> >>         int     lbs_msg_msg;
> >>         int     lbs_task;
> >> +       int     lbs_xattr; /* number of xattr slots in new_xattrs array */
> >
> > No need for the comment, we don't do it for the other fields.
>
> I asked for the comment. lbs_xattr is the number of entries, which is
> different from the other fields. The other fields contain blob sizes in
> bytes. Inconsistent behavior should be noted.

Fair enough.  Since that's the case, let's encode something in the
field name itself so that every user has a slight reminder that it is
a count and not a size.  How about 'lbs_xattr_count' or similar?

-- 
paul-moore.com