nntp-open-via-rlogin-and-telnet doesn't work with OpenSSH_4.3p2

nntp-open-via-rlogin-and-telnet doesn't work with OpenSSH_4.3p2

[Katsumi Yamaoka]

Hi,

(The culprit who increased quimby's INN log is me.)

I've upgraded my pc to Fedora Core 5, in which OpenSSH_4.3p2 is
contained.  And I realized that Gnus cannot connect to foreign
news servers using `nntp-open-via-rlogin-and-telnet'.  Here's
one of servers:

(nntp "quimby"
      (nntp-address "news.gnus.org")
      (nntp-end-of-line "\n")
      (nntp-open-connection-function nntp-open-via-rlogin-and-telnet)
      (nntp-via-address "inter.mediate.host")
      (nntp-via-rlogin-command "ssh")
      (nntp-via-rlogin-command-switches ("-C" "-t" "-e" "none")))

It opens an nntp connection to quimby by way of the intermediate
host as follows:

localhost ---(ssh)--- intermediate host ---(telnet)--- quimby

The cause of the problem is that OpenSSH_4.3p2 doesn't pass the
escape character "^]" to the telnet process.  It works as if
telnet to which the `mode character' command is not specified
runs.  In other words, that version of ssh doesn't pass a single
character to telnet immediately.  Only data terminated by the LF
character are passed.  Here is an actual session that I did
manually:

% ssh -C -t -e none inter.mediate.host 'telnet -8 news.gnus.org 119'
Trying 80.91.224.244...
Connected to news.gnus.org.
Escape character is '^]'.
200 quimby.gnus.org InterNetNews NNRP server INN 2.3.2 ready (posting ok).
^]

telnet> 

(the "telnet> " prompt appeared after I typed "^]" and RET.)

It might happen only in FC5, though.  To make it work, I changed
`nntp-open-via-rlogin-and-telnet' as follows:

--- nntp.el~	2006-01-20 08:28:08 +0000
+++ nntp.el	2006-04-14 10:19:26 +0000
@@ -1877,7 +1877,7 @@
       (nntp-wait-for-string "^\r*20[01]")
       (beginning-of-line)
       (delete-region (point-min) (point))
-      (process-send-string proc "\^]")
+      (process-send-string proc "\^]\n")
       (nntp-wait-for-string "^r?telnet")
       (process-send-string proc "mode character\n")
       (accept-process-output proc 1)

It works.  However, it doesn't seem to solve the problem that
the nntp connection doesn't exchange characters one by one.  So,
I don't have a will to install such one to the CVS repository.
Instead, I decided to downgrade the version of ssh (though I
have another means, e.g., `nntp-open-via-rlogin-and-netcat').
OpenSSH_4.3p1 doesn't work.  OpenSSH_4.2p1 doesn't work.
OpenSSH_4.1p1 works.  OpenSSH_4.0p1 works.  OpenSSH_3.9p1 works.

I will also report it to the OpenSSH community.  But before
doing so, does anyone notice I missed something?

(I will not be able to respond quickly until Monday.  Sorry.)

Re: nntp-open-via-rlogin-and-telnet doesn't work with OpenSSH_4.3p2

[Lars Magne Ingebrigtsen]

Katsumi Yamaoka <yamaoka@jpl.org> writes:

> OpenSSH_4.3p1 doesn't work.  OpenSSH_4.2p1 doesn't work.
> OpenSSH_4.1p1 works.  OpenSSH_4.0p1 works.  OpenSSH_3.9p1 works.
>
> I will also report it to the OpenSSH community.  But before
> doing so, does anyone notice I missed something?

Nope; didn't see anything obvious.

I tried the same just now.

larsi@deer:~$ ssh -v
OpenSSH_4.2p1 Debian-5, OpenSSL 0.9.8a 11 Oct 2005
larsi@deer:~$ ssh -C -t -e none deer 'telnet -8 news.gmane.org 119'
larsi@deer's password: 
Trying 80.91.229.5...
Connected to sea.gmane.org.
Escape character is '^]'.
200 news.gmane.org InterNetNews NNRP server INN 2.4.1 ready (posting ok).
^]
telnet> q
Connection closed.
Connection to deer closed.

That is, when I hit `^]', I got the telnet prompt immediately, without
hitting return.  So the version of OpenSSH 4.2p1 seems to work
differently that yours do.  (deer is an amd64 machine running sid, but
hasn't been updated in a month or so.)

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@gnus.org * Lars Magne Ingebrigtsen