[FEAT] Document sshd_config.d support

[four43]

Is this a new feature request?

• I have searched the existing issues

Legacy issue (?) here: #22

Wanted change

There is an old stale issue about how to modify the sshd_config. It seems like this is supported now:

d9b4e93

I'm unsure how to use this though. I just want to make a single file to modify one param in the sshd_config - basically to enable tcp forwarding.

I don't see my file getting properly mapped in. I'm sure I'm doing it wrong. Just some info in the README to show how to use this feature would go a long way.

Reason for change

Great features deserve docs! This seems very cool, telling users about them is good.

Proposed code change

No response

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[thespad]

It should be as simple as creating one or more .conf files in /config/sshd/sshd_config.d/ that set valid sshd_config directives, and that will then get imported on startup as part of the sshd config.

You can confirm that your existing sshd_config contains the correct, and enabled, include

# Include configuration snippets before processing this file to allow the
# snippets to override directives set in this file.
Include /config/sshd/sshd_config.d/*.conf

Though note that it will not get set to that if the /config/sshd/sshd_config.d/ doesn't exist on container startup.

[four43]

Alright I might just be a moron then.

I have an empty config dir, except for this one conf script:

$ ls -la ./scripts/openssh-server/config/sshd/sshd_config.d/tcp_forward_allow.conf 
-rw-r--r-- 1 root 1000 23 Jul 24 16:01 ./scripts/openssh-server/config/sshd/sshd_config.d/tcp_forward_allow.conf

    volumes:
      - ./scripts/openssh-server/config:/config

Run the container, jumping in via docker exec

root@openssh-server:/# ls /config/sshd/sshd_config.d/tcp_forward_allow.conf
/config/sshd/sshd_config.d/tcp_forward_allow.conf

root@openssh-server:/# cat /etc/ssh/sshd_config | grep -E -v '^(#.*|[[:space:]]*$)'
AuthorizedKeysFile      .ssh/authorized_keys
PasswordAuthentication no
AllowTcpForwarding no
GatewayPorts no
X11Forwarding no
PidFile /config/sshd.pid
Subsystem       sftp    internal-sftp

It doesn't seem to be adding that line (as I thought it would be form that linked commit). I'm running latest with a fresh pull.

Any ideas? I appreciate the help.

EDIT: Ah I see it in the /config/sshd/sshd_config file:

root@openssh-server:/# cat /config/sshd/sshd_config | grep -E -v '^(#.*|[[:space:]]*$)'
Include /config/sshd/sshd_config.d/*.conf
Port 2222
AuthorizedKeysFile      .ssh/authorized_keys
PasswordAuthentication no
AllowTcpForwarding no
GatewayPorts no
X11Forwarding no
PidFile /config/sshd.pid
Subsystem       sftp    internal-sftp

Is your version of SSH using that? not the /etc one?

[thespad]

It won't because it doesn't use that file at all, we explicitly pass -f /config/sshd/sshd_config when starting sshd so that you can run the container (almost) entirely out of /config

[four43]

Got it - okay that was me just misunderstanding then. Alright well I appreciate it. This issue is probably enough for others to find on this topic at this point.

Thanks for all your help @thespad