[systemd-devel] [PATCH] SELINUX: add /sys/fs/selinux mount point to put selinuxfs

[Mimi Zohar]

On Wed, 2011-05-11 at 16:52 +0200, Kay Sievers wrote:
> On Wed, May 11, 2011 at 16:43, Greg KH <greg at kroah.com> wrote:
> > On Wed, May 11, 2011 at 04:27:59PM +0200, Kay Sievers wrote:
> >> On Wed, May 11, 2011 at 15:54, Greg KH <greg at kroah.com> wrote:
> >> > On Wed, May 11, 2011 at 01:22:42PM +0200, John Johansen wrote:
> >> >> On 05/11/2011 03:59 AM, Greg KH wrote:
> >> >> > On Tue, May 10, 2011 at 03:55:24PM -0700, Casey Schaufler wrote:
> >> >> >> On 5/10/2011 3:34 PM, Greg KH wrote:
> >> >> >>> From: Greg Kroah-Hartman <gregkh at suse.de>
> >> >> >>>
> >> >> >>> In the interest of keeping userspace from having to create new root
> >> >> >>> filesystems all the time, let's follow the lead of the other in-kernel
> >> >> >>> filesystems and provide a proper mount point for it in sysfs.
> >> >> >>>
> >> >> >>> For selinuxfs, this mount point should be in /sys/fs/selinux/
> >> >> >>
> >> >> >> It seems that we might want this to be an LSM interface standard.
> >> >> >> Is the call to kobject_create_and_add and associated cleanup all
> >> >> >> that's required? I would want Smack to follow the convention as
> >> >> >> well.
> >> >> >
> >> >> > You could always just create a subdir under /sys/security/ if you have
> >> >> > your own filesystem, but I don't think that Smack has one, right?
> >> >> >
> >> >> > Is it going to get one?  If so, we might want to revisit the idea of
> >> >> > securityfs if no one is actually using it...
> >> >> >
> >> >> resending, as this looks to have been lost
> >> >>
> >> >> AppArmor, IMA, and TOMOYO are using securityfs currently.
> >> >
> >> > Great, then it will not go anywhere.
> >>
> >> Just to get an idea how all this fits together. How can TPM bios and
> >> IMA/AppArmor share this directory? They have their own subdirs in
> >> there, or both just use the securityfs infrastructure and not their
> >> own filesystem on top?
> >
> > Only one security module is allowed to be loaded/active at any one point
> > in time, so they can't step on each other.
> 
> Right, but what I don't understand is CONFIG_TCG_TPM, which seem to
> use securityfs, and is not a LSM. This and AppArmor/IMA can be used at
> the same time, can't it? They share securityfs then?
> 
> Kay

As securityfs was written by Greg, perhaps his original intention was
for a single LSM to use it at a time, but currently that is not the
case. Other subsystems (eg. IMA, TPM, and hopefully EVM) are using it,
defining their own subdirectory.

Mimi