Package: xdm Version: 1:1.0.1-6 Severity: important Hello,
After upgrading to Xorg 7.0 on two of my boxes (running Debian unstable), I am unable to log into X using xdm. As soon as I enter my login / password in the xdm dialog box, the X server is reset and xdm restarts. After doing some tests I think the problem is related to the 'unusual' network interfaces I have on my machine -- I'm using OpenVPN on my boxes and it creates 'tun' virtual network interfaces, that are not 'real' ethernet interfaces. By looking at the xdm source code, it seems that xdm forks a child process after successful user authentication, in order to handle the user X session. That child process starts by writing some .Xauthority files in the user home directory, containing the list of IP addresses of all the local network interfaces (DefineSelf() function in xdm/auth.c). When I have OpenVPN running, the xdm child process crashes when iterating over the list of my network interfaces IP addresses. It seems that the DefineSelf() function calls the ConvertAddr() function with a NULL saddr argument. A SIGSEGV signal is therefore sent to the xdm child process, and xdm restarts immediately. It is possible to prevent the problem by switching to false the DisplayManager*authorize option in the /etc/X11/xdm/xdm-config file, but I don't think that is very secure. I'm running a 2.6.16 kernel I compiled myself. I think the problem may be reproduced simply by running OpenVPN before authenticating in xdm. Regards, Yann Grossel -- System Information: Debian Release: testing/unstable APT prefers unstable APT policy: (500, 'unstable'), (500, 'testing'), (500, 'stable') Architecture: i386 (i686) Shell: /bin/sh linked to /bin/bash Kernel: Linux 2.6.16.1 Locale: LANG=C, LC_CTYPE=C (charmap=ISO-8859-15) (ignored: LC_ALL set to en_GB.ISO-8859-15) Versions of packages xdm depends on: ii cpp 4:4.0.3-3 The GNU C preprocessor (cpp) ii debconf [debconf-2.0] 1.5.0 Debian configuration management sy ii libc6 2.3.6-7 GNU C Library: Shared libraries ii libice6 1:1.0.0-3 X11 Inter-Client Exchange library ii libpam0g 0.79-3.1 Pluggable Authentication Modules l ii libselinux1 1.30-1 SELinux shared libraries ii libsm6 1:1.0.0-4 X11 Session Management library ii libx11-6 2:1.0.0-6 X11 client-side library ii libxau6 1:1.0.0-3 X11 authorisation library ii libxaw7 1:1.0.1-5 X11 Athena Widget library ii libxdmcp6 1:1.0.0-4 X11 Display Manager Control Protoc ii libxext6 1:1.0.0-4 X11 miscellaneous extension librar ii libxinerama1 1:1.0.1-4 X11 Xinerama extension library ii libxmu6 1:1.0.1-3 X11 miscellaneous utility library ii libxpm4 1:3.5.4.2-3 X11 pixmap library ii libxt6 1:1.0.0-4 X11 toolkit intrinsics library ii x11-common 1:7.0.15 X Window System (X.Org) infrastruc ii xbase-clients 1:7.0.0-5 miscellaneous X clients xdm recommends no packages. -- debconf information excluded -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
