[ovs-dev] [PATCH 0/4] selinux: introduce a transition domain for loading kmods

[Aaron Conole]

On linux systems, the initial start of openvswitch attempts to load
the openvswitch.ko kernel module.  This module allows openvswitch to
utilize the kernel datapath.

Some of these linux systems, notably Fedora and RHEL, use selinux to
enforce additional restrictions on various processes by way of allowing
or disallowing access from a specific selinux domain to a particular
operation on an selinux type.  On these systems, the openvswitch
initialization will be run from the 'openvswitch_t' selinux domain.
Attempts by a process in the 'openvswitch_t' selinux domain to load a
kernel module will be denied.

One solution would be to simply allow 'openvswitch_t' to load a kernel
directly.  This essentially means that 'openvswitch_t' would really be
'unconfined_t' - since an attacker that can control the code can issue
a kernel load.

The solution implemented here uses a labeled file in the openvswitch
scripts directory, which is writable only by root.  That file will force
a domain transition to the 'openvswitch_load_module_t' domain.  The
'openvswitch_load_module_t' domain will then be granted permissions to
load a kernel module.

Please vet the new permissions in 2/4 *carefully*.  I've tried to keep
it as restricted as possible.  If there are any useful selinux interfaces
that would simplify the permission grants needed for the new domain, I'm
happy to spin a v2.

Aaron Conole (4):
  ovs-kmod-ctl: introduce a kernel module load script
  selinux: create a transition type for module loading
  selinux: introduce domain transitioned kmod helper
  rhel: selinux-policy to invoke proper label macros

 debian/openvswitch-switch.install  |   1 +
 debian/openvswitch-switch.manpages |   1 +
 rhel/openvswitch-fedora.spec.in    |  12 +-
 rhel/openvswitch.spec.in           |   2 +
 selinux/.gitignore                 |   4 +
 selinux/automake.mk                |   3 +-
 selinux/openvswitch-custom.fc.in   |   1 +
 selinux/openvswitch-custom.te.in   |  79 ++++++++++++-
 utilities/.gitignore               |   1 +
 utilities/automake.mk              |   5 +
 utilities/ovs-ctl.in               |  32 +-----
 utilities/ovs-kmod-ctl.8           | 103 +++++++++++++++++
 utilities/ovs-kmod-ctl.in          | 228 +++++++++++++++++++++++++++++++++++++
 utilities/ovs-lib.in               |  12 +-
 14 files changed, 439 insertions(+), 45 deletions(-)
 create mode 100644 selinux/openvswitch-custom.fc.in
 create mode 100644 utilities/ovs-kmod-ctl.8
 create mode 100644 utilities/ovs-kmod-ctl.in

-- 
2.14.3