[Bug 1812466] Re: netboot: failed to parse DNS settings set by dhclient

[Launchpad Bug Tracker]

Status changed to 'Confirmed' because the bug affects multiple users.

** Changed in: dropbear (Ubuntu)
       Status: New => Confirmed

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to initramfs-tools in Ubuntu.
https://bugs.launchpad.net/bugs/1812466

Title:
  netboot: failed to parse DNS settings set by dhclient

Status in dropbear package in Ubuntu:
  Confirmed
Status in initramfs-tools package in Ubuntu:
  Confirmed

Bug description:
  I am setting up diskless netboot for Ubuntu LiveCDs, with following
  kernel arguments:

  ```
  boot=casper netboot=nfs nfsroot=192.168.89.10:/extracted/livecd toram
  ```

  I have noticed the following strange error messages after dhcp (also
  see the attachment):

  ```
  /init: /run/net-ens3.conf: line 8: 202.38.64.56: not found
  /init: /run/net-ens3.conf: line 8: 202.38.64.56: not found
  /init: /run/net-ens3.conf: line 8: 202.38.64.56: not found
  no search or nameservers found in /run/net-ens3.conf /run/net-ens3.conf /run/net6-*.conf
  /init: /run/net-ens3.conf: line 8: 202.38.64.56: not found
  /init: /run/net-ens3.conf: line 8: 202.38.64.56: not found
  ```

  I manually broke the init process, and found line 8 of /run/net-
  ens3.conf is:

  ```
  IPV4DNS0=192.168.88.1 202.38.64.56 202.38.64.17
  ```

  The problematic code is in the `netinfo_to_resolv_conf` function of
  `scripts/functions`. It sources `/run/net-ens3.conf` (which is
  obviously not in correct shell syntax due to the space inserted
  between multiple DNS servers) to get network settings:

  ```
  . "$f" || { echo "WARN: failed '. \"$f\"'" 1>&2; return 1; }
  ```

  The bug is introduced by commit a77729e9, which replaced IP-config
  with dhclient. While IP-config seems to write each DNS in `IPV4DNS0`,
  `IPV4DNS1`, etc., dhclient write all DNS in `IPV4DNS0`, which is not
  expected by `netinfo_to_resolv_conf`.

  I can confirm 18.10 LiveCDs are affected.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/dropbear/+bug/1812466/+subscriptions