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Bug #2250

OpenGGSN requires to run as root for no apparent reason

Added by laforge 5 months ago. Updated 7 days ago.

Status:
Closed
Priority:
Low
Assignee:
Category:
-
Target version:
-
Start date:
05/10/2017
Due date:
% Done:

100%

Spec Reference:

Description

OpenGGSN currently requires root (or rather CAP_NET_ADMIN) to run. There's no really good/technical reason for that, except for the fact that it currently seems to insist on creating the tun device inside libgtp, as well as setting the IP address/mask of that tun device.

The standard procedure is to have 'ip tunnel' or 'tunctl' create a tun/tap device and "chown" that to a given user/group. The program then simply uses that device without having to create it or modify it's IP address config.

If OpenGGSN could be configured to use such a pre-existing (persistent) tun device, it should be easy to run as non-root / non-CAP_NET_ADMIN.


Related issues

Related to OsmoGSMTester - Feature #1850: migrate osmo-gsm-tester from sysmocom internal jenkins to public jenkins Closed 11/18/2016
Related to OsmoGSMTester - Feature #2251: run osmo-gsm-tester in user land Closed 05/11/2017

History

#1 Updated by laforge 5 months ago

Quick mock-up/hack shows that it is possible to
  • set ifr.ifr_name to the name of the pre-existing tun device before caling ioctl(TUNSETIFF) in lib/tun.c
  • skip the tun_setaddr()
    and then openggsn runs as regular user.
So we'd have to
  • add a config option to specify the tun device name via config file
  • skip calling tun_setaddr in ggsn/ggsn.c if there is no "net" config file line (or similar criteria).

#2 Updated by laforge 5 months ago

  • Related to Feature #1850: migrate osmo-gsm-tester from sysmocom internal jenkins to public jenkins added

#3 Updated by neels 5 months ago

  • Related to Feature #2251: run osmo-gsm-tester in user land added

#4 Updated by laforge 3 months ago

  • Assignee set to msuraev
  • Priority changed from Normal to Low

#6 Updated by msuraev 3 months ago

laforge wrote:

Quick mock-up/hack shows that it is possible

Is this available on some branch somewhere?

#7 Updated by laforge 3 months ago

On Fri, Jul 21, 2017 at 02:42:21PM +0000, msuraev [REDMINE] wrote:

Quick mock-up/hack shows that it is possible

Is this available on some branch somewhere?

just pushed as laforge/non-root - it's super trivial.

#8 Updated by laforge about 1 month ago

  • Status changed from New to Resolved
  • Assignee changed from msuraev to laforge
  • % Done changed from 0 to 100

This has been implemented in OsmoGGSN (not OpenGGSN) as part of the introduction of a VTY interface.

If there are no "ifconfig" lines in the configuration file, and the tun device already exists at GGSN startup time, then no root privileges are required anymore.

#9 Updated by laforge 7 days ago

  • Status changed from Resolved to Closed

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