[Bug 2049860] Re: cloud-init cloud-config for ssh broken in jammy

[Thomas Bechtold]

Verified that it works via:

- test image build for EC2
- launching a instance with user-data to set password authentication: "aws ec2 run-instances --image-id ami-01046735e1a43b710 --instance-type m6a.large --key-name toabctl --user-data file:///home/tom/tmp/cloud-config --tag-specifications 'ResourceType=instance,Tags=[{Key=Name,Value=toabctl-jammy-sru-validation}]'"
- login with password: ssh -o PubkeyAuthentication=no ubuntu at 3.66.190.126

Ordering looks good now:

# ls -al /etc/ssh/sshd_config.d/
total 16
drwxr-xr-x 2 root root 4096 Feb  1 14:23 .
drwxr-xr-x 4 root root 4096 Feb  1 14:23 ..
-rw------- 1 root root   27 Feb  1 14:23 50-cloud-init.conf
-rw-r--r-- 1 root root   26 Feb  1 13:44 60-cloudimg-settings.conf

# sshd -T|grep passwordauth
passwordauthentication yes



** Tags removed: verification-needed-jammy
** Tags added: verification-done-jammy

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https://bugs.launchpad.net/bugs/2049860

Title:
  cloud-init cloud-config for ssh broken in jammy

Status in cloud-images:
  Fix Committed
Status in cloud-images focal series:
  New
Status in livecd-rootfs package in Ubuntu:
  New
Status in livecd-rootfs source package in Jammy:
  Fix Committed

Bug description:
  [impact]
  cloud-config overrides via cloud-init for ssh do no longer work. Eg.

  #cloud-config
  ssh_pwauth: True

  doesn't enable password authentication anymore.

  The reason is that https://git.launchpad.net/livecd-
  rootfs/commit/live-build/ubuntu-
  cpc/hooks.d/chroot/052-ssh_authentication.chroot?h=ubuntu/jammy&id=3b2eeb017153cbbfc8935f9447e00d196e34d983
  is a wrong backport using the wrong filename
  /etc/ssh/sshd_config.d/10-cloudimg-settings.conf . it needs to be
  /etc/ssh/sshd_config.d/60-cloudimg-settings.conf . See
  https://git.launchpad.net/livecd-rootfs/tree/live-build/ubuntu-
  cpc/hooks.d/chroot/052-ssh_authentication.chroot?h=ubuntu/master which
  is the correct change in the ubuntu/master branch.

  This bug needs only fixing in Jammy and Focal because the fix is
  correct in > Jammy. Jammy has this bug already in the -updates pocket
  but Focal only has the wrong fix in its git branch.

  [test plan]
  * build an image with the proposed fix
  * use a cloud-init cloud-config data to enable ssh password auth (which is disabled by default)
  * check after image boot with "sshd -T" if password authentication is enabled
  * make sure that the file written by cloud-init in /etc/ssh/sshd_config.d/ has a lower number than the file from the image (cloudimg-settings.conf)

  [ Where problems could occur ]
  The change does rename a single file to have correct ordering between the prebuilt cloud images and cloud-init. There are edge-cases where this could create problems but those are acceptable:

  - rebuilt images based on the Ubuntu image which try to delete
  10-cloudimg-settings.conf would no longer work

  But in general this is a bug fix for the changes introduced in
  LP:#1968873

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