Subject: Re: SSH X11 forwarding crashes clients.
To: Lars-Johan Liman <liman@autonomica.se>
From: Johnny Billquist <johnny.billquist@softjar.se>
List: current-users
Date: 12/01/2005 15:46:43
Yup.
Security "feature".
use "ssh -Y"
Johnny
Lars-Johan Liman wrote:
> Anyone else seeing this?
>
> 1) Start from 3.99.11 2005-11-28.
>
> 2) Start X server and xterm on local machine.
>
> 3) ssh with X11 forwarding to remote older box.
>
> 4) Start X11 application on remote box (e.g. xterm or emacs).
>
> 5) Select text in window opened by remote application.
> 5a) If emacs, watch client die.
>
> 6) Paste text into local window using <SHIFT> + <INSERT>.
> 6b) If other client (e.g. xterm), watch client die.
>
> The error message I get is:
>
> X protocol error: BadWindow (invalid Window parameter) on protocol request 38
>
> On a Mac (see below) I get the following from xterm:
>
> xterm: warning, error event received:
> X Error of failed request: BadAtom (invalid Atom parameter)
> Major opcode of failed request: 18 (X_ChangeProperty)
> Atom id in failed request: 0x17e
> Serial number of failed request: 187
> Current serial number in output stream: 189
>
>
> Now to the strange thing: If I open up direct access to the X server
> (xhost +<remote-IP#> - for testing puposes only) and manually set the
> DISPLAY to the <IP#> of the local machine (as one did in the old
> insecure days ... ;-) on the remote machine _before_ issuing the
> commands that start the X11 applications in question, I have no
> problems what so ever. Window opens, cut-n-paste works like a charm.
>
> I can repeat this perfectly fine using remote boxes with
>
> NetBSD 1.6ZK, sshd version OpenSSH_3.6.1 NetBSD_Secure_Shell-20030917
>
> MacOS X 10.3.9, sshd version OpenSSH_3.6.1p1+CAN-2004-0175
>
> Linux/Debian unstable, kernel 2.6.12, sshd OpenSSH_4.2p1 Debian-4, OpenSSL 0.9.7g 11 Apr 2005
>
> Since the problem does appear with very different remote hosts, but
> doesn't appear with direct X11 connections, I presume the problem sits
> in my "local machine" and in its ssh client or some component thereof -
> possibly OpenSSL.
>
> BTW, the other way around seems to work fine. Using the X server on
> the Mac, logging in (ssh with X11 forw) to my 3.99.11 box, starting
> window, etc., seems to be OK.
>
> Comments? "Me-too"s? Known issue? Fix?
>
> Cheers,
> /Liman
> #----------------------------------------------------------------------
> # There are 10 kinds of people in the world. Those who understand
> # binary numbers, and those who don't.
> #----------------------------------------------------------------------
> # Lars-Johan Liman, M.Sc. ! E-mail: liman@autonomica.se
> # Senior Systems Specialist ! HTTP : //www.autonomica.se/
> # Autonomica AB, Stockholm ! Voice : +46 8 - 615 85 72
> #----------------------------------------------------------------------
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt@update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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