Configuring a user should not configure root's authorized_keys

[ubuntu-server-builder]

This bug was originally filed in Launchpad as LP: #1871879

Launchpad details

affected_projects = []
assignee = None
assignee_name = None
date_closed = None
date_created = 2020-04-09T16:53:41.587279+00:00
date_fix_committed = None
date_fix_released = None
id = 1871879
importance = wishlist
is_complete = False
lp_url = https://bugs.launchpad.net/cloud-init/+bug/1871879
milestone = None
owner = apollo13
owner_name = Florian Apolloner
private = False
status = triaged
submitter = apollo13
submitter_name = Florian Apolloner
tags = []
duplicates = []

Launchpad user Florian Apolloner(apollo13) wrote on 2020-04-09T16:53:41.587279+00:00

When ssh_authorized_keys is configured in user-data keys are unconditionally copied into /root/.ssh/authorized_keys.

If disable_root is set to true it leaks the actual configured username: "Please login as the user XYZ rather than the user root." With disable_root set to false you can login.

It would be great if there were a way to actually disable root and not touch it at all. I fully understand that the info message is useful for new users, but it would be great to have a way to leave root alone.

[ubuntu-server-builder]

Launchpad user Andras Kovacs(andras0602) wrote on 2020-04-09T17:19:57.903239+00:00

It would be great!

Now I do it like:
runcmd:

• rm -f /root/.ssh/authorized_keys
  But a proper option would be better.

[ubuntu-server-builder]

Launchpad user Dan Watkins(oddbloke) wrote on 2020-04-14T14:43:17.798613+00:00

Hi Florian, Andras, thanks for the report and confirmation! Do you have any thoughts on what configuration for this might look like?

[ubuntu-server-builder]

Launchpad user Florian Apolloner(apollo13) wrote on 2020-04-14T15:31:08.351698+00:00

Hi Dan,

thanks for taking this into consideration. My gut-feeling would be an option ala "root_login_help_msg: <true|false>" (Naming is hard). Preferably I'd have it set to false by default but I doubt that will fly :D