Bug#1074766: openssh-server: upgrading to openssh-server (1:9.2p1-2+deb12u3) resets /etc/ssh/sshd_config file without any prompt

Hello Colin,

Here is the output of apt/term.log:

Log started: 2024-07-02  00:04:13
(Reading database ... 64456 files and directories currently installed.)
Preparing to unpack .../openssh-sftp-server_1%3a9.2p1-2+deb12u3_amd64.deb
...
Unpacking openssh-sftp-server (1:9.2p1-2+deb12u3) over (1:9.2p1-2+deb12u2)
...
Preparing to unpack .../openssh-server_1%3a9.2p1-2+deb12u3_amd64.deb ...
Unpacking openssh-server (1:9.2p1-2+deb12u3) over (1:9.2p1-2+deb12u2) ...
Preparing to unpack .../openssh-client_1%3a9.2p1-2+deb12u3_amd64.deb ...
Unpacking openssh-client (1:9.2p1-2+deb12u3) over (1:9.2p1-2+deb12u2) ...
Setting up openssh-client (1:9.2p1-2+deb12u3) ...
Setting up openssh-sftp-server (1:9.2p1-2+deb12u3) ...
Setting up openssh-server (1:9.2p1-2+deb12u3) ...
Replacing config file /etc/ssh/sshd_config with new version
rescue-ssh.target is a disabled or a static unit not running, not starting
it.
ssh.socket is a disabled or a static unit not running, not starting it.
Processing triggers for man-db (2.11.2-2) ...
Processing triggers for ufw (0.36.2-1) ...
Log ended: 2024-07-02  00:04:16

I've attached the sshd_config from my last week backup, I've just changed
the port number I use to a random one.

I had the same problem on 4 different servers I upgraded last night. Maybe
it's not related to openssh-server and I just noticed the problem on this
package...

Also note that I've recently enabled apt-listchange prompting on all these
servers:

cat /etc/apt/listchanges.conf
[apt]
frontend=pager
which=both
email_address=root
email_format=html
confirm=true
headers=false
reverse=false
save_seen=none
no_network=false

Here is the command I used to check and apply security updates:

sudo apt update && sudo apt dist-upgrade -V && sudo apt autoremove -y

Regards,

John Wellesz

On Tue, Jul 2, 2024 at 5:24 PM Colin Watson <[email protected]> wrote:

> On Tue, Jul 02, 2024 at 03:05:16PM +0000, John Wellesz wrote:
> > I used apt upgrade to install the security update available for
> >   openssh-server
> >
> >    * What was the outcome of this action?
> >
> > It overwrote /etc/ssh/sshd_config without promtping, erasing the custom
> settings
> > and almost locking me out as a result (my custom port setting was gone
> > as well as other changes I've made).
> >
> >    * What outcome did you expect instead?
> >
> > I expected to receive the usual prompt when a configuration file is
> > modified asking me what I want to do but there was none.
>
> We'll need to be able to reproduce this problem before being able to do
> anything about it.  (I have a modified /etc/ssh/sshd_config on my own
> stable system and it wasn't overwritten on upgrade.)
>
> Can you please provide a copy of your modified /etc/ssh/sshd_config,
> along with the output of the relevant apt run (which should be preserved
> in /var/log/apt/term.log)?
>
> --
> Colin Watson (he/him)                              [[email protected]]
>