search

canonical / core18

The core18 base snap
14 stars 26 forks source link

static: make /etc/dbus-1/session.d writable #150

Closed jhenstridge closed 4 years ago

jhenstridge commented 4 years ago

This supercedes for PR #98, and is intended for use by https://github.com/snapcore/snapd/pull/6258

In order to have dbus-daemon look for service activation files under /var/lib/snapd, we need to drop configuration fragments into /etc/dbus-1/session.d and /etc/dbus-1/system.d. The latter was already writable so the dbus interface can poke holes in the system bus security policy, but the former was not.

I've simply added the session.d directory here, but an alternative would be to simply make all of /etc/dbus-1 writable, which would save a bind mount. The downside of that is that on transition the /etc/dbus-1/session.d directory might go missing. That is unlikely to cause problems though because:

  1. Ubuntu Core devices don't tend to run a session bus.

  2. dbus-daemon's configuration file parser does not treat a missing <includedir> as an error: https://gitlab.freedesktop.org/dbus/dbus/-/blob/master/bus/config-parser.c#L2478

zyga commented 4 years ago

@jhenstridge do you think we could make it better for core 20 (one less bind mount)?