[Bug 932275] Re: Bogus or no nameserver information written to /etc/network/interfaces

Matthew L. Dailey matthew.l.dailey at dartmouth.edu
Fri Feb 24 13:47:13 UTC 2012


Hi Stéphane,

I'm attaching an example /e/n/i file. Due to the nature of this bug,
it's actually writing out initialized memory space, so the results are
random. In the majority of cases, since this is a newly-booted system,
the memory being pointed to is probably zeros, so nothing will actually
get written. In fact, in trying to replicate it this morning, I could
only do it with my preseeded install, not with a vanilla one.

I hope this helps. Let me know if you have any other questions or need
any other info.

** Attachment added: "interfaces file with bogus nameservers"
   https://bugs.launchpad.net/ubuntu/+source/netcfg/+bug/932275/+attachment/2778733/+files/interfaces

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to netcfg in Ubuntu.
https://bugs.launchpad.net/bugs/932275

Title:
  Bogus or no nameserver information written to /etc/network/interfaces

Status in “netcfg” package in Ubuntu:
  Fix Released

Bug description:
  Doing a test install of precise with static networking, I noticed
  bogus (non-ASCII) data written on the dns-nameservers line in
  /etc/network/interfaces, which was then be carried over to resolv.conf
  by the resolvconf package. Other times, this line would simply not be
  in /etc/network/interfaces at all.

  After looking at the code and doing some testing, the problem seems to
  be that at the end of static.c, the netcfg_write_resolvconf_options is
  called with the nameserver_array array, but this array is never
  actually populated. So, in the best-case scenario, it's pointing at
  zeros in memory and doesn't put anything in the interfaces file, but
  in other cases, spits out whatever happens to be in memory. :-) As
  near as I can tell, it looks like this happened somewhere between
  version 1.68 from debian and version 1.68ubuntu1.

  The fix is to either pass the namserver array from the iface struct,
  or just pass the struct itself and deal with it in the
  netcfg_write_resolvconf_options function.

  I'll attach two patches - a quick-and-dirty one and one that matches
  the way the netcfg_write_resolv function works.

  I'd love to have someone who's more familiar with the code have a look
  and make sure that I'm not doing anything bad, and then if it's
  helpful, I'm happy to create a debdiff.

  Thanks and let me know if you have any questions or if there's any
  more info I can provide.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/netcfg/+bug/932275/+subscriptions




More information about the foundations-bugs mailing list