[Bug 809885] Re: Single-quoted entries are invalid in /etc/resolv.conf on network install with NetworkManager disabled

[Dave Walker]

** Changed in: casper (Ubuntu)
    Milestone: precise-alpha-1 => precise-alpha-2

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https://bugs.launchpad.net/bugs/809885

Title:
  Single-quoted entries are invalid in /etc/resolv.conf on network
  install with NetworkManager disabled

Status in “casper” package in Ubuntu:
  In Progress

Bug description:
  Binary package hint: casper

  Ubuntu release: Oneiric Ocelot (LiveCD daily image from 2011-07-13).
  Package: this is present in Casper 1.271.
  What I expected to happen: valid entries in  /etc/resolv.conf.
  What happened instead: all entries in /etc/resolv.conf have single quotes around the values, causing problems while installing some other packages.

  More details about this problem:

  In a testing environment, we do network installs using the daily
  Oneiric images. One particularity is that we disable NetworkManager by
  creating an interface entry in /etc/interfaces prior to booting. Thus,
  scripts/casper-bottom/23networking is the sole responsible for
  creation of /etc/resolv.conf.

  23networking parses the /tmp/net-${DEVICE}.conf file and takes the
  DNSDOMAIN value to fill up both the domain and search entries in
  resolv.conf, as well as the IPV4DNS{0,1} entries for the DNS servers.
  It ignores the rest of the values in the conf file. The ipconfig
  utility, which generates /tmp/net-${DEVICE}.conf files based on DHCP
  information, adds single quotes around the values. Files look like
  this:

  (actual net-eth0.conf from an Oneiric install)

  DEVICE='eth0'
  IPV4ADDR='10.153.104.249'
  IPV4BROADCAST='10.153.104.255'
  IPV4NETMASK='255.255.255.0'
  IPV4GATEWAY='10.153.104.1'
  IPV4DNS0='10.153.104.60'
  IPV4DNS1='0.0.0.0'
  HOSTNAME=''
  DNSDOMAIN='canonical.com'
  NISDOMAIN=''
  ROOTSERVER='10.153.104.60'
  ROOTPATH=''
  filename='/oneiric-desktop-i386/pxelinux.0'

  
  23networking takes the values verbatim, including the quotes, and thus generates a resolv.conf that looks like this:

  # /etc/resolv.conf
  # Autogenerated by casper
  search 'canonical.com'
  domain 'canonical.com'
  nameserver '10.153.104.60'
  nameserver '0.0.0.0'

  This gives problems later on: while installing postfix, it constructs
  the hostname by taking the domain name from resolv.conf, coming up
  with things like host.'domain.com' which are invalid and cause postfix
  configuration to fail. Also, although an unlikely use case, trying to
  access hosts by name with this invalid resolv.conf also fails.

  This bug is not usually apparent because most installations use
  NetworkManager, which takes over resolv.conf, rebuilding it from DHCP
  information, which it doesn't quote, unlike ipconfig.

  This bug is very similar in nature to bug 709364. Whereas the change
  in ipconfig (from klibc) that caused that bug double-quoted DNSDOMAIN
  to allow for multiple dns domains, this change to ipconfig single-
  quotes all entries in the generated file, to prevent arbitrary code
  execution from scripts which simply source the /tmp/net-${DEVICE}.conf
  file (not the case with casper so it can safely strip the quotes).
  This change was introduced in klibc in this commit:

  commit 46a0f831582629612f0ff9707ad1292887f26bff
  Author: Ulrich Dangel <uli at spamt.net>
  Date:   Fri Apr 15 18:22:08 2011 +0200

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