LXC Template Security Improvements

Mission

This project's mission is to eliminate the use of predictable passwords in LXC templates. It all started with BZ 1132001 which attached bug reports to fedora-all, EPEL 7, and EPEL 6. The problem exists upstream and the upstream developers are welcoming fixes.

This is part of the Fedora Security Team's 90-day challenge.

Updates

Stéphane Graber would prefer to see two improvements happen in tandem (mentioned in this GitHub PR):

1. Remove sshd from each template by default
2. Use a shared shell script so that password handling is identical for all containers.

This presents a challenge as some containers have a normal user with sudo privileges (like Ubuntu).

It seems like a shell script could have logic resembling the following:

• Did the user provide a password for root (or the regular user with sudo privileges)?
  • If password supplied, use that one for root or the regular user with sudo privileges
  • If password not supplied, generate a random password and present that to the user at the end of the build
• Is sshd present in the container's rootfs?
  • If yes, remove it
  • If no, pass

Templates

The upstream templates are on Github. Each template will be documented here as it's reviewed.

Work in progress
This section is being updated regularly. --Mhayden (talk) 17:31, 18 June 2015 (UTC)

Alpine

The template can't download an APK that passes verification. It also doesn't seem to set a root password anywhere during the container creation.

AltLinux

The password for root is set to rooter for all builds.

ArchLinux

The user can specify a root password but root's account is left without a password if a password isn't provided.

Busybox

Password for root is set to 'root' by default. Default ssh configuration allows root logins without a password as well.

CentOS

No changes needed as randomized root passwords are already applied during build.

Cirros

The password for root isn't set, but a user called cirros has the password cubswin:).

Debian

The upstream Debian template current sets root's password to root. There's a proposed fix waiting on feedback from Debian's LXC package maintainer.

Fedora

No changes needed as randomized root passwords are already applied during build.

Gentoo

If a root password isn't specified, the root password is set to toor.

OpenMandriva

The root password is set to root by default.

OpenSuse

The root password is set to root by default.

Oracle

The root password is set to root by default. The oracle user has the password oracle.

Plamo

The root password is set to root by default.

Ubuntu

The Ubuntu template disables the root account but makes a regular user with sudo privileges that has ubuntu as a username and password (unless a user password is specified on the command line during build).

A fix has been proposed.

The Ubuntu Cloud template allows a user to specify cloud-init data to configure the container once it's booted. If the user doesn't specify any data, the root account is locked.