[Bug 2068729] Re: pam_radius_auth: Failed to open RADIUS IPv6 socket: Address family not supported by protocol

[Sergio Durigan Junior]

I was finally able to reproduce it here, despite the lack of more
specific instructions.

$ lxc launch noble n-radius --vm
$ lxc shell n-radius
# apt update && apt install libpam-radius-auth
# vim /etc/pam.d/sudo

Add the following line to the file:

auth       sufficient pam_radius_auth.so debug

# cat > /etc/pam_radius_auth.conf << _EOF_
127.0.0.1                   secret             3
[::1]                       secret             3
_EOF_

# echo 'GRUB_CMDLINE_LINUX="${GRUB_CMDLINE_LINUX} ipv6.disable=1"' >> /etc/default/grub.d/99-disable-ipv6.cfg
# update-grub

# echo "ubuntu ALL=(ALL:ALL) ALL" > /etc/sudoers.d/support
# passwd ubuntu

Choose an easy password here, like "123".

Reboot the machine, and shell in again:

# su - ubuntu
# sudo true

Type the password, and see the crash.

Now, what I found is that this crash is unrelated to this bug.  You can
reproduce it using the version of libpam-radius-auth that's currently in
the archive on Noble *and* Oracular.  Plucky has a newer version of the
package, which I haven't tested.

I believe this crash deserves its own separate bug report, and should
probably be fixed before addressing this particular bug.

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https://bugs.launchpad.net/bugs/2068729

Title:
  pam_radius_auth: Failed to open RADIUS IPv6 socket: Address family not
  supported by protocol

Status in libpam-radius-auth package in Ubuntu:
  Triaged
Status in shadow package in Ubuntu:
  Confirmed

Bug description:
  New and fully updated 24.04 LTS with disabled IPv6 (The CISA secure
  config states that IPv6 is to be disabled unless it's in use).

  lsb_release -rd:
  No LSB modules are available.
  Description:    Ubuntu 24.04 LTS
  Release:        24.04

  apt-cache policy libpam-radius-auth
  libpam-radius-auth:
    Installed: 2.0.1-1
    Candidate: 2.0.1-1
    Version table:
   *** 2.0.1-1 500
          500 http://au.archive.ubuntu.com/ubuntu noble/universe amd64 Packages
          100 /var/lib/dpkg/status

  What you expected to happen:
  Based on https://github.com/FreeRADIUS/pam_radius/blob/master/src/pam_radius_auth.c, the pam_radius_auth module must support ipv6 and ipv4 options.

  /etc/pam.d/sshd:
  auth       sufficient   pam_radius_auth.so  conf=/etc/pam_radius_auth.conf retry=3 ipv4=yes ipv6=no debug

  What happened instead:
  2024-06-07T22:07:57.499460+10:00 ubuntu sshd[584305]: pam_radius_auth: 2.0.1, built on Aug 19 2023 at 14:08:42
  2024-06-07T22:07:57.499672+10:00 ubuntu sshd[584305]: pam_radius_auth: unrecognized option 'ipv4=yes'
  2024-06-07T22:07:57.499880+10:00 ubuntu sshd[584305]: pam_radius_auth: unrecognized option 'ipv6=no'
  2024-06-07T22:07:57.500051+10:00 ubuntu sshd[584305]: pam_radius_auth: DEBUG: conf_file='/etc/pam_radius_auth.conf' use_first_pass=no try_first_pass=no skip_passwd=no retry=3 localifdown=no client_id='' accounting_bug=no ruser=no prompt='Password: ' force_prompt=no prompt_attribute=no max_challenge=0 privilege_level=no
  2024-06-07T22:07:57.500279+10:00 ubuntu sshd[584305]: pam_radius_auth: Got user name: 'test'
  2024-06-07T22:07:57.502892+10:00 ubuntu sshd[584305]: pam_radius_auth: Failed to open RADIUS IPv6 socket: Address family not supported by protocol

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