On Fri, 2017-03-31 at 14:09 +0200, Dominick Grift wrote: > I vaguely recall that we discussed this issue or at least that i > mentioned it here but i can't recall the outcome if any: > > So today on my rawhide system i noticed that i somehow forgot to add > support for the smc_socket class (i suspect that is part of the > extended socket class patches) > > I added the class (which i suppose is unordered like the othe > extended socket classes) but as soon as I loaded up the policy with > the new unordered smc_socket class the system became unusable. > > This is because the dbus object manager became confused due to my > adding a new (unordered) class at runtime, and that the dbus class > was no longer working. > > Modern systems heavily rely on dbus at the heart and so it is > undesire-able that this happens. > > A reboot clears this issue up but adding (unordered) classes at > runtime should not cause these issues i suspect dbusd doesn't use selinux_check_access() and therefore does not yet support reordering of their classes/permissions at runtime. The same is true of all userspace object managers created before selinux_check_access() was introduced - anything that directly calls security_compute_av() or avc_has_perm(). dbusd does call selinux_set_mapping() at startup, so it can correctly handle reordering of classes/permissions across restarts, but not while it is running. Calling selinux_set_mapping() again upon policy reloads (e.g. from policy_reload_callback() if (event == AVC_CALLBACK_RESET) before returning) may fix this problem, but requires proper locking. Even better would be to rid the dbusd selinux implementation of threading entirely, see https://bugs.freedesktop.org/show_bug.cgi?id=92831#c4 smc_socket was added by the kernel developers as part of the merge with net-next since we now trigger a build failure in the kernel if any new address families are introduced without adding a corresponding security class (so that SELinux always supports a separate class per network address family going forward). So there have been no policy patches submitted yet to define it in refpolicy even AFAIK. [1] https://github.com/SELinuxProject/selinux/issues/34 _______________________________________________ Selinux mailing list Selinux@xxxxxxxxxxxxx To unsubscribe, send email to Selinux-leave@xxxxxxxxxxxxx. To get help, send an email containing "help" to Selinux-request@xxxxxxxxxxxxx.
