openssh unix dev - Apr 2024 - D-bus integration

On Thu, 11 Apr 2024, Krzysztof Kowalski wrote:
> Dear OpenSSH developers,
> 
> I was looking at the fail2ban project and had an idea that instead of
parsing
> log files it could be possible to notify interested parties (like fail2ban)
> via (for instance) D-bus about a failed login attempt.
> 
> Other application could also use this protocol to notify about suspect
> behaviors. A central functionality will allow for other (new) projects to
> integrate without much effort.
> 
> What do you think?
As others have mentioned, we're really not in the mood for more library
dependencies right now. However, some people have asked for platform
features that would require D-bus support. I don't know much about the
D-bus protocol, but if a small D-bus client is just opening a unix domain
socket and writing a message to it then we could possibly support it
using a standalone implementation, like we just did for systemd.

-d

> I don't know much about the
> D-bus protocol, but if a small D-bus client is just opening a unix
> domain
> socket and writing a message to it then we could possibly support it
> using a standalone implementation, like we just did for systemd.
Afraid not, D-Bus is a stateful protocol with client authentication and
so much more, it's not something you really want to reimplement
locally, using one of the available libraries is the only reasonable
approach.

There are de-facto two usable libraries for C projects, the first one
is GDBus, provided by the GLib library, and pretty much requires buying
into the whole GLib model of main loop and event processing. The second
one is sd-bus, which is smaller and can be used in other event/main
loops implementation and, I'm sure you'll be delighted to know, it's
from libsystemd ;-)

https://www.freedesktop.org/wiki/Software/DBusBindings/

-- 
Kind regards,
Luca Boccassi