sftp idle timeout

[Damien Miller]

On Mon, 29 May 2017, Tomas Kuthan wrote:

> In this particular deployment, limiting the idle timeout to sftp
> sessions only would actually be preferable. High numbers of regular
> sftp users are expected, with only an occasional admin shell access
> here and there.
>
> What are your reasons for not liking the sftp-server-centric solution?
> (I admit implementing the timeout in the underlying ssh layer is a
> more generic solution and it allows for a more graceful tear-down.)
>
> I see ssh idle timeout surfaced on the alias a couple times before,
> but never made it into the code. Are you saying that the idea itself
> is viable and that a patch could be accepted?

The problem is that the mainloop is an old select()-based monster, so
adding a decent timer system to it will be ugly and will make it harder
to fix later.

Once Markus finishes the refactoring that he's working on at the moment,
I'm planning on taking a look at cleaning the mainloop up and adding a
decent timer mechanism.

I'm reticent to add a special-case timer to sftp-server before that
happens, though improving sftp's reporting of the underlying ssh
connection going away seems like a good idea.

-d