selinux: add bus service access control

selinux: add bus service access control

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

This patch adds the ability to look at the calling process that is trying to
do dbus calls into systemd, then it checks with the SELinux policy to see if
the calling process is allowed to do the activity.

The basic idea is we want to allow NetworkManager_t to be able to start and
stop ntpd.service, but not necessarly mysqld.service.

Similarly we want to allow a root admin webadm_t that can only manage the
apache environment.  systemctl enable httpd.service, systemctl disable
iptables.service bad.

To make this code cleaner, we really need to refactor the dbus-manager.c code.
 This has just become a huge if-then-else blob, which makes doing the correct
check difficult.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://www.enigmail.net/

iEYEARECAAYFAlBJBi8ACgkQrlYvE4MpobOzTwCdEUikbvRWUCwOb83KlVF0Nuy5
lRAAnjZZNuc19Z+aNxm3k3nwD4p/JYco
=yops
-----END PGP SIGNATURE-----