Re: XFree86 insecurity

From: Czako Krisztian (slapicat_private)
Date: Fri Nov 21 1997 - 17:50:31 PST

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    On Fri, 21 Nov 1997, shegget wrote:
    
    > Program:   XF86_*, the XFree86 servers (XF86_SVGA, XF86_VGA16, ...)
    > Version:   Tested on XFree86 3.3.1 (current), 3.2.9 and 3.1.2.
    >            Other versions as well.
    > OS:        All
    
    Except Debian Linux, where the X servers aren't setuid root!
    
    > Impact:    The XFree86 servers let you specify an alternate configuration
    >            file and do not check whether you have rights to read it.
    >            Any user can read files with root permissions.
    
    One more reason to use Debian :)
    
    On my Debian 1.3.1 + hamm upgarde (XFree86 3.3.1):
    bash-2.00$ ls -l /usr/X11R6/bin/X*
    - -rwsr-xr-x   1 root     root         4728 Oct 18 06:58 /usr/X11R6/bin/X
    - -rwxr-xr-x   1 root     root       820544 Jun 20 16:41 /usr/X11R6/bin/XF86Setup
    - -rwxr-xr-x   1 root     root      2313580 Jul 17 15:33 /usr/X11R6/bin/XF86_S3
    - -rwxr-xr-x   1 root     root      1816864 Jun 20 16:41 /usr/X11R6/bin/XF86_VGA16
    
    bash-2.00$ cd /usr/X11R6/bin/
    bash-2.00$ ./X
    X: you are not authorised to run the X server
    
    bash-2.00$ dpkg -S /usr/X11R6/bin/X
    xbase: /usr/X11R6/bin/X
    
    So I suggest using this wrapper on all systems where possible.
    Another solution can be running xdm, and make xdm to start the X server.
    In this case you don't need the X server to be setuid root.
    
    Slapic
    
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