[refpolicy] modules_object_t vs. modules_dep_t labeling

[dac.override@gmail.com (Dominick Grift)]

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On Tue, Oct 06, 2015 at 01:29:13PM +0200, Dominick Grift wrote:
> On Mon, Oct 05, 2015 at 03:17:48PM -0400, Christopher J. PeBenito wrote:
> > On 10/5/2015 12:34 PM, Dominick Grift wrote:
> > > On Thu, Oct 01, 2015 at 11:58:25AM +0200, Miroslav Grepl wrote:
> > >> We have more and more bugs with mislabeled /lib/modules/*/modules.dep*
> > >> files. There is a default label for them - modules_dep_t but we get them
> > >> labeled as modules_object_t. Yes, we can add filename transition rules
> > >> and also find a reason why they get wrong labeling (in progress).
> > > 
> > >> But is there a big advantage to have these two labels. At least I don't
> > >> see it from the policy point of view (sesearch).
> > > 
> > >> Thank you.
> > > 
> > > 
> > > Still not verified but:
> > > 
> > > /sbin/depmod is a link to /bin/kmod
> > > 
> > > So i suspect /bin/kmod now creates the modules_dep files via rpm_script_t %post and
> > > the /sbin/new_kernel_pkg shell script:
> > > 
> > > doDepmod() {
> > >     [ -n "$verbose" ] && echo "running depmod for $version"
> > >         depmod -ae -F /boot/System.map-$version $version
> > >         }
> > > 
> > > but because insmod_t is lacking the appropriate auto object type transitions and because insmod is
> > > unconfined, the files get created with the wrong label.
> > > 
> > > So you should copy the auto object type transition rules for modules_dep
> > > from depmod to insmod i suspect
> > > 
> > > I would not want insmod_t to be able to mess with module_object_t type
> > > files.
> > > 
> > > But yes, in Fedora insmod is unconfined...
> > 
> > Thanks for digging through this issue.  For the time being, we'll keep
> > what we have.  Miroslav, if the type transition Dominick suggests works,
> > then we can put it in refpolicy.
> > 
> 
> I have confirmed that the above applies, and have it implemented now in
> my personal policy.
> 
> If one ensures that /bin/kmod is labeled with the insmod_exec_t type and
> if one ensures that insmod_t creates files in modules_object_t type
> directories with a auto object type transition from modules_object_t to
> modules_dep_t then the module dep files should get labeled properly
> (there should be no real need for name-base auto object type transitions)
> 
> if you do use name-based auto object type transitions then make sure you
> at least add name modules.dep.tmp (it renames it later to modules.dep)
> 

Although there seems to be more going on (something else seems to be
maintaining modules_dep files as well). I need a few more kernel
installs to see what is going on exactly besides kmod creating
modules.dep.tmp and maybe some other module_dep files

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Dominick Grift
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