"Subsystem 'sftp' already defined" error in openssh-9 when using Include

[Artem Russakovskii]

Hi everyone,

For the last several releases (perhaps with the release of openssh 9?),
upgrading each version  of openssh started wiping the current sshd_config
and replacing it with the default config, at least on OpenSUSE 15.4 via
zypper/yast.

I was thinking of ways to mitigate this and thought I'd move the config to
sshd_config.d/ in the hopes that it will be then called by the main config.

However, two issues exist here, and I'm not sure how to resolve them.

1. "Subsystem 'sftp' already defined." since it's defined in sshd_config
and redefined in sshd_config.d/custom_config.
>From what I can tell, this is supposed to be fixed by
https://groups.google.com/g/linux.debian.bugs.dist/c/jTXWWobiGpY with this
code https://bugzilla.mindrot.org
/attachment.cgi?id=3591&action=diff&collapsed=&headers=1&format=raw, but I
don't currently understand if it's released (I'm on openssh-9.3p2 and it
still throws the "Subsystem 'sftp' already defined" error) or when it will
be released. Would appreciate any clarity here.

2. Even if the above is resolved, I think it still presents a problem since
the default sshd_config doesn't include this line "Include
sshd_config.d/*". If an upgrade removes it, then I'll still need to
manually add it every time.

The config was never force-replaced prior to a few months ago (prior to
9?). How is everyone else dealing with this problem?

Thank you.

Sincerely,
Artem

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