From: Stephen Smalley [mailto:sds@tycho.nsa.gov]
Sent: 05 March 2012 20:16
On Mon, 2012-03-05 at 17:26 +0000, Moray Henderson wrote:
> Is there an easy way for a script to detect whether MLS mode is
enabled?
>
> On CentOS 5 whether running normally or in Anaconda's rescue mode,
> SELINUX=enforcing (or permissive), SELINUXTYPE=targeted, there is no
> /etc/selinux/mls directory and cat /selinux/mls prints "1".
>
> However, with CentOS running normally a command to set a context
works,
> while from rescue mode the same command fails with "cannot setup
default
> context" unless I add and :s0 MLS piece. That's fine when I'm doing
things
> manually, but I'd like a script to detect whether it's being run in
an
> environment that needs the :s0 added. I don't want to just add :s0
all the
> time, in case it's already there in the context string I'm trying to
set.
Technically you should always provide the MLS piece if /selinux/mls is
1
(is_selinux_mls_enabled() in C or selinux.is_selinux_mls_enabled() in
python). The only reason you get away with not specifying it in
multi-user mode is that mcstransd is running.
Thanks Stephen. So if /selinux/mls is 1 a suitable way to fetch the full context of
(say) everything in root whether we're in single or multi-user mode would be:
SUFFIX=`/bin/ps -C mcstransd > /dev/null && echo :s0`
find / -maxdepth 1 -printf "%p:\t%Z${SUFFIX}\n"
It won't be run on a system that actually uses MLS, so I can get away with hardwiring
the :s0.
Moray.
“To err is human; to purr, feline.”