[libvirt PATCH 01/13] security: add SELinux policy for virt
Daniel P. Berrangé
berrange at redhat.com
Fri Aug 20 11:33:28 UTC 2021
On Thu, Aug 19, 2021 at 05:23:48PM +0200, Vit Mojzis wrote:
>
> On 10. 08. 21 18:35, Daniel P. Berrangé wrote:
> > On Tue, Aug 10, 2021 at 10:39:23AM +0200, Pavel Hrdina wrote:
> > > On Fri, Aug 06, 2021 at 06:47:58PM +0100, Daniel P. Berrangé wrote:
> > > > From: Nikola Knazekova <nknazeko at redhat.com>
> > > >
> > > > SELinux policy was created for:
> > > >
> > > > Hypervisor drivers:
> > > > - virtqemud (QEMU/KVM)
> > > > - virtlxcd (LXC)
> > > > - virtvboxd (VirtualBox)
> > > >
> > > > Secondary drivers:
> > > > - virtstoraged (host storage mgmt)
> > > > - virtnetworkd (virtual network mgmt)
> > > > - virtinterface (network interface mgmt)
> > > > - virtnodedevd (physical device mgmt)
> > > > - virtsecretd (security credential mgmt)
> > > > - virtnwfilterd (ip[6]tables/ebtables mgmt)
> > > > - virtproxyd (proxy daemon)
> > > >
> > > > SELinux policy for virtvxz and virtxend has not been created yet,
> > > > because I wasn't able to reproduce AVC messages. These drivers
> > > > run in unconfined_domain until the AVC messages are reproduced
> > > > internally and policy for these drivers is made.
> > > >
> > > > Signed-off-by: Nikola Knazekova <nknazeko at redhat.com>
> > > > ---
> > > > src/security/selinux/virt.fc | 111 ++
> > > > src/security/selinux/virt.if | 1984 ++++++++++++++++++++++++++++++++
> > > > src/security/selinux/virt.te | 2078 ++++++++++++++++++++++++++++++++++
> > > > 3 files changed, 4173 insertions(+)
> > > > create mode 100644 src/security/selinux/virt.fc
> > > > create mode 100644 src/security/selinux/virt.if
> > > > create mode 100644 src/security/selinux/virt.te
> > > >
> > > > diff --git a/src/security/selinux/virt.fc b/src/security/selinux/virt.fc
> > > > new file mode 100644
> > > > index 0000000000..554e1094d9
> > > > --- /dev/null
> > > > +++ b/src/security/selinux/virt.fc
> > > > @@ -0,0 +1,111 @@
> > > > +HOME_DIR/\.libvirt(/.*)? gen_context(system_u:object_r:virt_home_t,s0)
> > > > +HOME_DIR/\.libvirt/qemu(/.*)? gen_context(system_u:object_r:svirt_home_t,s0)
> > > > +HOME_DIR/\.cache/libvirt(/.*)? gen_context(system_u:object_r:virt_home_t,s0)
> > > > +HOME_DIR/\.cache/libvirt/qemu(/.*)? gen_context(system_u:object_r:svirt_home_t,s0)
> > > > +HOME_DIR/\.config/libvirt(/.*)? gen_context(system_u:object_r:virt_home_t,s0)
> > > > +HOME_DIR/\.config/libvirt/qemu(/.*)? gen_context(system_u:object_r:svirt_home_t,s0)
> > > > +HOME_DIR/VirtualMachines(/.*)? gen_context(system_u:object_r:virt_home_t,s0)
> > > > +HOME_DIR/VirtualMachines/isos(/.*)? gen_context(system_u:object_r:virt_content_t,s0)
> > > These two doesn't look like libvirt selinux bits, more like virt-manager
> > > or some other tool.
> > Rationale is largely lost in the mists of time to be honest. $HOME/VirtualMachines
> > does make sense for desktop virt use case I think, while the below rules make
> > sense as a direct translation of libvirt's system paths.
> >
> > I think its ok to have both really
> >
> > > > +HOME_DIR/\.local/share/libvirt/images(/.*)? gen_context(system_u:object_r:svirt_home_t,s0)
> > > > +HOME_DIR/\.local/share/libvirt/boot(/.*)? gen_context(system_u:object_r:svirt_home_t,s0)
> > > > +/var/lib/libvirt(/.*)? gen_context(system_u:object_r:virt_var_lib_t,s0)
> > > > +/var/lib/libvirt/boot(/.*)? gen_context(system_u:object_r:virt_content_t,s0)
> > > > +/var/lib/libvirt/images(/.*)? gen_context(system_u:object_r:virt_image_t,s0)
> > > > +/var/lib/libvirt/isos(/.*)? gen_context(system_u:object_r:virt_content_t,s0)
> > > > +/var/lib/libvirt/lockd(/.*)? gen_context(system_u:object_r:virt_var_lockd_t,s0)
> > > > +/var/lib/libvirt/qemu(/.*)? gen_context(system_u:object_r:qemu_var_run_t,s0-mls_systemhigh)
> > > > +
> > > > +/var/log/log(/.*)? gen_context(system_u:object_r:virt_log_t,s0)
> > > Based on commit from selinux-policy 63ead48cf8 this seems vdsm related.
> > > I don't think that we use this directory in libvirt.
> > Yeah, that's dubious.
> Good point, we'll move it out of virt policy.
> >
> > > > +/var/log/libvirt(/.*)? gen_context(system_u:object_r:virt_log_t,s0)
> > > > +/var/run/libvirtd\.pid -- gen_context(system_u:object_r:virt_var_run_t,s0)
> > > > +# Avoid calling m4's "interface" by using en empty string
> > > > +/var/run/libvirt/interfac(e)(/.*)? gen_context(system_u:object_r:virtinterfaced_var_run_t,s0)
> > > > +/var/run/libvirt/nodedev(/.*)? gen_context(system_u:object_r:virtnodedevd_var_run_t,s0)
> > > > +/var/run/libvirt/nwfilter(/.*)? gen_context(system_u:object_r:virtnwfilterd_var_run_t,s0)
> > > > +/var/run/libvirt/secrets(/.*)? gen_context(system_u:object_r:virtsecretd_var_run_t,s0)
> > > > +/var/run/libvirt/storage(/.*)? gen_context(system_u:object_r:virtstoraged_var_run_t,s0)
> > > > +
> > > > +/var/run/virtlogd\.pid -- gen_context(system_u:object_r:virtlogd_var_run_t,s0)
> > > > +/var/run/virtlxcd\.pid -- gen_context(system_u:object_r:virt_lxc_var_run_t,s0)
> > > > +/var/run/virtqemud\.pid -- gen_context(system_u:object_r:virtqemud_var_run_t,s0)
> > > > +/var/run/virtvboxd\.pid -- gen_context(system_u:object_r:virtvboxd_var_run_t,s0)
> > > > +/var/run/virtproxyd\.pid -- gen_context(system_u:object_r:virtproxyd_var_run_t,s0)
> > > > +/var/run/virtinterfaced\.pid -- gen_context(system_u:object_r:virtinterfaced_var_run_t,s0)
> > > > +/var/run/virtnetworkd\.pid -- gen_context(system_u:object_r:virtnetworkd_var_run_t,s0)
> > > > +/var/run/virtnodedevd\.pid -- gen_context(system_u:object_r:virtnodedevd_var_run_t,s0)
> > > > +/var/run/virtnwfilterd\.pid -- gen_context(system_u:object_r:virtnwfilterd_var_run_t,s0)
> > > > +/var/run/virtnwfilterd-binding\.pid -- gen_context(system_u:object_r:virtnwfilterd_var_run_t,s0)
> > > > +/var/run/virtsecretd\.pid -- gen_context(system_u:object_r:virtsecretd_var_run_t,s0)
> > > > +/var/run/virtstoraged\.pid -- gen_context(system_u:object_r:virtstoraged_var_run_t,s0)
> > > [...]
> > >
> > > I was not able to figure out on which selinux policy is this one based
> > > on as the upstream for rawhide from <https://github.com/fedora-selinux/selinux-policy.git>
> > > is a bit different. There are some cosmetics changes but I see two major
> > > differences:
> > >
> > > - the upstream policy doesn't have split-daemon bits compared to
> > > this one, I checked it and it looks reasonable but I'm not that
> > > familiar with selinux policy
> > Now I compare the two, I see there's a bunch of stuff in the current
> > fedora virt.te that doesn't exist in this virt.te.
>
> This policy has been mostly rewritten by Nikola Knazekova to work with the
> split daemon configuration.
>
> It's only been tested using libvirt-tck and by running some VM by hand so we
> could use your help running other tests you have available.
>
> There has actually been some progress on the policy since I last updated the
> PR. The latest version is available here:
> https://github.com/5umm3r15/selinux-policy/blob/libvirt-selinux/policy/modules/contrib/virt.te
>
> https://github.com/5umm3r15/selinux-policy/blob/libvirt-selinux/policy/modules/contrib/virt.fc
>
> https://github.com/5umm3r15/selinux-policy/blob/libvirt-selinux/policy/modules/contrib/virt.if
>
> The MLS parts of the policy are still not 100% since we are not sure about
> some access that is taking place during testing with libvirt-tck.
>
> Please see:
> https://gitlab.com/libvirt/libvirt-tck/-/merge_requests/8#note_601463944
Doh I missed those questions.
> >
> > So if we deploy this, then its likely to break stuff that's in the
> > current virt.te that we've omitted.
> >
> > I should have checked this more closely before re-sendig, as I just
> > blindly assumed that the differences to fedora-selinux had been
> > eliminated after my original review comments :-(
> >
> > > - the upstream policy has important `system.token` issue fix that
> > > we've seen recently introduced by upstream commit <1f761d0bbd>
> >
> > My view for pulling any SElinux policy into libvirt.git is that we need
> > to untangle the current fedora selinux virt policy first to remove all
> > the non-libvirt pieces. It should then be a direct copy into libvirt.git
> > with no modifications.
> >
> > So I don't think this is mergable as it exists now.
>
> The policy has been split to virt and virt_supplementary (https://github.com/5umm3r15/selinux-policy/blob/libvirt-selinux/policy/modules/contrib/virt_supplementary.te),
> where virt_supplementary has the bits that are non-libvirt (this part will
> stay in selinux-policy repo).
IIUC, the repo 5umm3r15/selinux-policy is not the main repo
used for Fedora policy.
If I merged this policy in libvirt now, and we deployed it on
Fedora we would regress becaue virt_supplementary doesn't
exist in any current Fedora / rawhide IIUC.
Is there an ETA for merging the virt/virt_supplementary stuff
into the official Fedora policy, and updating rawhide / RHEL-9,
so that we can in turn merge & release the libvirt parts ?
Regards,
Daniel
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