Can't talk to Bluez from my snap

snapd
1

I’m getting this error when trying to talk to BlueZ over dbus:

error time=1537907351.253802 sender=org.freedesktop.DBus -> destination=:1.32 error_name=org.freedesktop.DBus.Error.AccessDenied reply_serial=7 string "Rejected send message, 3 matched rules; type="method_call", sender=":1.32" (uid=1000 pid=7337 comm="/snap/mbed-edge/11/./mept-ble --edge-domain-socket") interface="org.freedesktop.DBus.ObjectManager" member="GetManagedObjects" error name="(unset)" requested_reply="0" destination=":1.3" (uid=0 pid=1891 comm="/snap/bluez/165/usr/lib/bluetooth/bluetoothd -E ")"

I’ve tried to package my snap like this: https://docs.ubuntu.com/core/en/stacks/bluetooth/bluez/docs/reference/enablement/snapping-bluetooth-enabled-application

Then connected the plug/socket:
admin@C031051823-00197:/snap$ snap interfaces | grep bluez
bluez:service bluez:client,mbed-edge:client

I’m getting denied by the policies set in /etc/dbus-1/system.d/snap.bluez.bluez.conf and /etc/dbus-1/system.d/snap.bluez.obex.conf. Manually editing those files fixes my problem.

What’s the right way to package my app so that I’m allowed to send to org.bluez?

2

What changes did you make to /etc/dbus-1/system.d/snap.bluez.bluez.conf and /etc/dbus-1/system.d/snap.bluez.obex.conf?

3

I changed the lines that that used to be

<policy context="default">
    <deny send_destination="org.bluez"/>
</policy>

to

<policy context="default">
    <allow send_destination="org.bluez"/>
</policy>

I did this to verify that the policy is indeed causing my messages to be rejected.

4

It sounds like you are trying to access bluez as non-root. On core, the dbus policy allows connections as root since there is no polkit/etc for non-root authorization. If you run your command under sudo I suspect it will work. daemons in your snap run as root, so they’ll be able to access the service (if the interface is connected).

5

Running under sudo did the job. Thanks!