ModemManager and d-bus permissions in OpenWrt

[Peter Naulls]

On 11/22/22 15:13, Hugo Osvaldo Barrera wrote:
> On Tue, 22 Nov 2022, at 20:48, Peter Naulls wrote:
>> This is really an OpenWrt question, but I wanted to understand the specifics
>> with MM.  We're undergoing a security review, and it's been pointed out that
>> d-bus runs as non-root. I've created a new "dbus" user and group like ubus
>> has and have d-bus run under it as per its config file.
>>
>> Everything seems OK with MM, and indeed I think this is the only user of
>> it under my OpenWrt setup, hence the question here.
>>
>> Is this likely to break anything?
> 
> ModemManager interacts with hardware drivers themselves, it needs some rather
> elevated capabilities. A non-root user won't work immediately; you'd need to
> make sure that the user can access all the lower layer in the hardware stack.

The question isn't about ModemManager running as another user, it's about
d-bus, of which MM is the only user on OpenWrt on my system. As far as I can
tell, it works fine.