Hi valentina,
Yes we continue in that direction.
The process is what Casey described: after some investigations, if we find that
we can adjust all the DAC & smack permissions to make a given daemon run as
something else than root (and without high privileges), we'll do it.
But the most important is not to run as root or not: IMO, what is essential is
to give the exact level of privileges needed by a given service, not less (of
course, this wouldn't work) and not more (this would be a security gap). I mean
that running some daemon as a special user who has a lot of privileges is not
always the solution: having multiple 'roots' doesn't make things simpler.
The good question is perhaps: why this *specific* daemon needs so much
privileges ? Is it essential for the system ? Can't we make it run with less
privileges ? Could we split the daemon in two parts ? etc.
Also remember that Tizen, as any other Linux distro, relies on upstream
projects. We can tweak things, but there are always design limits for that. So,
at one point, if another "more secure" (open or private) implementation for a
given service must take place, it's certainly possible: you'd just have to
compile the service with Tizen toolchain and write the corresponding core API.
The Tizen architecture, with its service layer, was probably designed with that
flexibility in mind...
Best regards,
--
Stéphane Desneux
Intel OTC - Vannes/FR
gpg:1CA35726/DFA9B0232EF80493AF2891FA24E3A2841CA35726
Valentina Giusti wrote:
On 08/12/2014 03:08 PM, Stéphane Desneux wrote:
Hi Valentina,
Hi Stephane,
As Casey and Carsten said: things are not black and white... but simply
gray :) We *try* to reduce the daemons running as root as much as
possible. But it's not an absolute rule.
Sometimes, it's possible to migrate a daemon from root to <some system
user> without much difficulties. A good example is weston in
Tizen:Common: it runs as a 'display' user, who has the proper rights on
the DRM and input devices.
For some other daemons, it can become more tricky.
If I take a quick look on a recent Tizen:Common snapshot, I can see that
there are some daemons running as root, as you noticed:
root 159 1 0 03:22 ? 00:00:00 /usr/sbin/ofonod -n
root 161 1 0 03:22 ? 00:00:00 /usr/bin/alarm-server
root 168 1 0 03:22 ? 00:00:00 /usr/sbin/connmand -n
root 172 1 0 03:22 ? 00:00:00 /usr/bin/security-server
root 173 1 0 03:22 ? 00:00:00 /usr/bin/media-server
root 175 1 0 03:22 ? 00:00:00
/usr/bin/notification-service
root 239 1 0 03:22 ? 00:00:00 /lib/bluetooth/bluetoothd -E
root 344 1 0 03:22 ? 00:00:00 /usr/sbin/wpa_supplicant -u
root 1037 173 0 03:23 ? 00:00:00 media-thumbnail-server
In this list, I see 3 categories:
- some daemons can very probably run as system users (media-server,
media-thumbnail-server, ofonod, alarm-server), if we're able to define
the appropriate rights
- for network and connectivity daemons (connmand, wpa_supplicant,
bluetoothd), it may be more tricky to migrate to non-root users, but
this needs some investigation
- some services need to run as root (security-server AFAIK)
As Casey pointed, migrating from root to system users for some daemons
is an ongoing effort.
thanks for your detailed answer. I was actually wondering how you proceeded with
the identification of the processes that can be run as system processes and if
you planned to continue in that direction for the services that still run as
root.
My guess is that this would help also with having a multi-user/multi-session
system.
Best Regards,
- Valentina
Best regards,
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