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From:   Russell Coker <russell@coker.com.au>
To:     Chris PeBenito <pebenito@ieee.org>
Cc:     selinux-refpolicy@vger.kernel.org
Subject: Re: udevadm etc
Date:   Thu, 10 Dec 2020 11:02:44 +1100
Message-ID: <5107170.hMIqiVgsFT@liv>
In-Reply-To: <c15139e9-6349-4ae4-90c9-c721cbd1c389@ieee.org>
References: <3161997.pUvnUksOUX@liv> <c15139e9-6349-4ae4-90c9-c721cbd1c389@ieee.org>
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On Thursday, 10 December 2020 9:00:38 AM AEDT Chris PeBenito wrote:
> On 12/9/20 7:38 AM, Russell Coker wrote:
> > In systemd verision 247.1 (which is in Debian/Unstable now) systemd-udevd
> > is a symlink to udevadm.  In systemd version 241 (in Debian/Buster) it's
> > not a symlink.  The systemd changelog doesn't mention this change so I
> > don't know exactly when it happened.
> > 
> > type_transition init_t udevadm_exec_t:process udevadm_t;
> > type_transition initrc_t udevadm_exec_t:process udevadm_t;
> > type_transition sysadm_t udevadm_exec_t:process udevadm_t;
> > type_transition consolekit_t udev_exec_t:process udev_t;
> > type_transition devicekit_disk_t udev_exec_t:process udev_t;
> > type_transition hald_t udev_exec_t:process udev_t;
> > type_transition hotplug_t udev_exec_t:process udev_t;
> > type_transition init_t udev_exec_t:process udev_t;
> > type_transition initrc_t udev_exec_t:process udev_t;
> > type_transition kernel_t udev_exec_t:process udev_t;
> > type_transition virtd_t udev_exec_t:process udev_t;
> > 
> > Above is a list of the relevant type_transition rules from refpolicy taken
> > from git 3 days ago (there don't appear to be any udev changes since
> > then).
> > 
> > I think that the only thing to do is to have init_t and initrc_t run
> > udevadm in the udev_t domain.
> > 
> > Is it worth having a udevadm_t domain just for running it from sysadm_t or
> > should we have that run as udev_t too?
> 
> The udevadm_t domain is much smaller than udev_t, and critically doesn't
> have all the device access udev_t has.  Systemd merging the binaries into
> one doesn't necessarily mean the policy has to merge too.

Currently only 3 domains can transition to udevadm_t.  2 of those 3 also 
transition to udev_t so they can't use udevadm_t without code changes.  The 
only remaining domain is sysadm_t.

The question is not "do we have to merge the policy because systemd merges 
binaries" but "should we have a separate domain only used for sysadm_t"?

-- 
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