Chromebook: run a SSH server on Chrome OS

In this post, we’ll cover how to run a SSH server directly on Chrome OS (ie not into a Crouton chroot).

One of the first things I do on any machine (FreeBSD, Linux, Mac OS X or Windows) is to install, run and configure the SSH server. It’s always convenient to be able to scp from and to a computer, or to log in remotely. Even for workstations.

Chrome OS is a reasonable if minimal standard Linux installation offering access to iptables and sshd (and openvpn by the way), so it’s as easy to run sshd and to allow incoming traffic on port 22.

Setup

1. If it’s not already done, switch your chromebook in developer mode, so you can execute commands as root.

Do a backup of your data, as you’ll wipe your current Chrome OS partitions.

On most recent machines, restart in recovery mode (ESC + REFRESH + POWER), then when it boots, CTRL + D to enter the developer mode.

Hit enter to turn off OS verification. It will then restart. Now and everytime after, you’ll need to do a CTRL + D to boot.

It will then wipe your chromebook and reinstall a fresh Chrome OS version. The process takes 6 to 7 minutes.

Former machines require to use an hardware switch, generally located below the battery. Be gentle with this switch, it breaks easily.

2. Launch a console with the shorcut ctrl + alt + t, then write shell to open a full bash shell (if the shell command isn’t available, you aren’t in developer mode).

Become root with sudo su.

3. Setup SSH keys :

4. Run SSH:

5. Allow world to connect to port 22:

6. Add your public keys to ~chronos/.ssh/authorized_keys file. Authentication by password isn’t available.

7. You’re now able to log in from the world to your chromebook.

Sources

Andrew Sutherland, cr-48 chromium os ssh server, 14 January 2011.

CentOS wiki contributors, IPTables, CentOS wiki.

December 2014 links

Some links of stuff I appreciated this month. Links to French content are in a separate post. You can also take the time machine to November 2014.

AI

What if instead to understand how the brain works, we copy the neural connections as is? This is what the OpenWorm project tries to do with C. elegans. And, big surprise, that works and allows a bot to move.

Wikipedia

An infographics of the locality of Wikipedia participants shows without any surprise they are mainly from Europe and North America.

If you’re into dumps, the Wikipedia / MediaWiki XML dump grepper will help you to find a particular piece of data, like the text of one article.

Tools

Dev / search. The silver searcher, ag, offers a faster approach than ack to search your code.

Fun / autogenerator. Some years ago, cgMusic offered an implementation on how a computer program could create music. Add some image generation techniques and a word generators, and you can have a fake music generator offering full albums. Ælfgar has stumbled upon Liquified Death by Income Yield.

GIS. Turf is a new open source JavaScript GIS library. This post explains the capabilities and features, including its great offline support.

Electronics

What if an Arduino embeds a web server and allows programmation from the web browser? This is exactly what the Photon by Spark does.

Quartz

An infographics showing satellites orbiting Earth and a point of view of the Uber economy.

Literature

The GoT series offer some comprehensive scenes of torture. Did you ask yourself their interest or need for the plot? Marie Brennan offers a great opinion in « Welcome to the Desert of the Real ».