Bug 463377

Summary: xguest fails due to incorrect selinux context
Product: [Fedora] Fedora Reporter: Matt Domsch <matt_domsch>
Component: libX11Assignee: Søren Sandmann Pedersen <sandmann>
Status: CLOSED RAWHIDE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: urgent Docs Contact:
Priority: urgent    
Version: 9CC: dwalsh, james, jokatzer, kem, mgrepl, poelstra, sandmann, sgrubb, torsten, xgl-maint, yaneti
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2008-10-23 20:49:52 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 438943    

Description Matt Domsch 2008-09-23 03:34:02 UTC
Description of problem:
xguest and dbus in rawhide, fails.

type=AVC msg=audit(1222140311.434:13): avc:  denied  { read write } for  pid=3476 
comm="dbus-daemon" path="socket:[13340]" dev=sockfs ino=13340 scontext=xguest_u:xguest_r:xguest_dbusd_t:s0 tcontext=xguest_u:xguest_r:xguest_t:s0 tclass=unix_stream_socket


Version-Release number of selected component (if applicable):
xguest-1.0.6-7.fc9.noarch
dbus-1.2.3-1.fc10.x86_64
dbus-glib-0.76-2.fc10.i386
dbus-devel-1.2.3-1.fc10.x86_64
dbus-glib-devel-0.76-2.fc10.x86_64
dbus-python-0.83.0-2.fc9.x86_64
dbus-libs-1.2.3-1.fc10.x86_64
dbus-libs-1.2.3-1.fc10.i386
ndesk-dbus-glib-0.4.1-3.fc9.x86_64
dbus-glib-0.76-2.fc10.x86_64
ndesk-dbus-0.6.1a-2.fc9.x86_64
dbus-x11-1.2.3-1.fc10.x86_64


How reproducible:
always

Steps to Reproduce:
1. install xguest
2. try logging in with user guest

  
Actual results:
fail

Expected results:
login succeeds

Additional info:

Comment 1 John Poelstra 2008-09-23 17:51:22 UTC
changing component to selinux-policy-targeted and adding to F10 blocker

Comment 2 Daniel Walsh 2008-09-23 19:04:32 UTC
Actually looks like this is a more general problem with pam_namespace.  Looks like gdm/login is not handling the /tmp file system being replaced.

Comment 3 Matt Domsch 2008-10-04 05:23:47 UTC
This fails on Fedora 9 now as well.

Comment 4 Daniel Walsh 2008-10-06 19:58:07 UTC
Xlib is not handling the abstract namespace any longer.  This is a major regression in Fedora 9, Either the kernel or Xlib is now broken, and any users of pam_namespace for /tmp will now break.  xguest is broken.

Comment 5 Joachim Katzer 2008-10-06 22:31:01 UTC
For Fedora9, the bug is apparently caused by one of the following packages:

xorg-x11-server-Xephyr-1.5.0-2.fc9.i386
xorg-x11-server-common-1.5.0-2.fc9.i386
xorg-x11-server-Xorg-1.5.0-2.fc9.i386

I could install all other updates from the newkey repos, including gdm, kernel and selinux, without breaking xguest (at least for XFCE desktop which I have tested in a VM). 
xorg-x11-server version 1.4.99.905-2.20080702.fc9.i386 was compatible with xguest.

Comment 6 Daniel Walsh 2008-10-08 11:52:31 UTC
xguest is using the pam_namespace to mount a temporary file system over /tmp during the login process.  X apps are supposed to connect to @/tmp/.X11-unix/X0 first and then fail over to  /tmp/.X11-unix/X0. Either this is no longer true or the first connection is failing for some reason.

You can get this behaviour by just renaming the /tmp/.X11-unix/X0 socket

# netstat -an | grep -i LIS.*X11
unix  2      [ ACC ]     STREAM     LISTENING     131718 @/tmp/.X11-unix/X1
unix  2      [ ACC ]     STREAM     LISTENING     560065 @/tmp/.X11-unix/X0
unix  2      [ ACC ]     STREAM     LISTENING     131719 /tmp/.X11-unix/X1
unix  2      [ ACC ]     STREAM     LISTENING     560066 /tmp/.X11-unix/X0

# cd /tmp/.X11-unix
# mv X0 X0.back
# xterm
Warning: This program is an suid-root program or is being run by the root user.
The full text of the error or warning message cannot be safely formatted
in this environment. You may get a more descriptive message by running the
program as a non-root user or by removing the suid bit on the executable.

Comment 7 Adam Jackson 2008-10-23 20:49:52 UTC
This is fixed in libxcb-1.1.91-4.fc10