Re: fds beyond 0/1/2

[Damien Miller <djm%mindrot.org@localhost>]

On Wed, 25 Aug 2010, der Mouse wrote:

(responding to this part until I digest the rest of the proposal)

> ---------------- data-eof%rodents.montreal.qc.ca@localhost
> 
> Standard ssh has no way to indicate EOF on one data flow without
> indicating EOF on the entire channel.  For input, this is not a
> problem, since there is only one data flow, but it is an issue for
> output, and, if any input fds are forwarded with fd-forward, it can be
> a problem for input too.  We deal with this issue with data-eof channel
> requests.

OpenSSH has had a eow%openssh.com@localhost SSH_MSG_CHANNEL_REQUEST to indicate
the missing half-close state for a while.

Unfortunately, it turns out that quite a few SSH implementations barf
when they see extension channel requests that they don't recognise, so
we turned it off for implementations that don't identify themselves
as OpenSSH. So much for an extensible protocol...

The documentation for this (and other OpenSSH extensions) is at:

http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL?rev=HEAD

-d