Bug 855070 - policy prevents xauth from accessing urandom chr_file
Summary: policy prevents xauth from accessing urandom chr_file
Alias: None
Product: Fedora
Classification: Fedora
Component: selinux-policy
Version: 17
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Miroslav Grepl
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2012-09-06 15:39 UTC by Antoine Martin
Modified: 2012-09-22 00:00 UTC (History)
3 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2012-09-22 00:00:11 UTC
Type: Bug

Attachments (Terms of Use)

Description Antoine Martin 2012-09-06 15:39:03 UTC
Description of problem: I create a number of virtual displays (either with Xvfb or with Xdummy) and when winswitch tries to set the xauth tokens for those displays, I get an selinux alert.

Version-Release number of selected component (if applicable): 

How reproducible: always.

Steps to Reproduce:
1. Start winswitch
2. Start an xpra session of any kind

Actual results:
session starts but the alert is issued.

Expected results:
session starts without alert.

Additional info:
This is pretty much what winswitch does when starting new xpra sessions:
* Xvfb +extension Composite -screen 0 3840x2560x24+32 -nolisten tcp -noreset -auth $XAUTHORITY :62
* /usr/bin/xauth add :62 MIT-MAGIC-COOKIE-1 9f5d3652e5ca73387e6913765eb1d96f
Obviously, the display number changes, and the xauth token is randomly pre-generated by winswitch.
Strangely enough, if I run those two commands from the shell, I don't get the alert. I have no idea why xauth behaves differently when ran from winswitch but at the end of the day, if xauth needs /dev/urandom, it should have it.

Comment 1 Antoine Martin 2012-09-10 05:36:19 UTC
I grabbed the exact command line used with xauth by doing:

mv /usr/bin/xauth /usr/bin/xauth.real
cat << EOF > /usr/bin/xauth


echo "" >> /tmp/xauth.log
date >> /tmp/xauth.log
echo "xauth $@"  >> /tmp/xauth.log
echo "PPID=$PPID"  >> /tmp/xauth.log
echo "PID=$$"  >> /tmp/xauth.log
echo "PP=`ps -ef | grep $PPID | grep -v grep`"  >> /tmp/xauth.log

/usr/bin/xauth.real "$@"

And this is what is run:

Mon Sep 10 12:26:07 ICT 2012
xauth add :61 MIT-MAGIC-COOKIE-1 3a36497f58b026cd0e002585e3e17252
PP=antoine  11242     1  0 12:26 ?        00:00:00 /bin/python /usr/bin/xpra --bind-tcp= --password-file=/home/antoine/.winswitch/server/sessions/61/session.pass --no-daemon --no-pulseaudio start :61
antoine  11243 11242  0 12:26 ?        00:00:00 Xvfb-for-Xpra-:61 +extension Composite -screen 0 3840x2560x24+32 -nolisten tcp -noreset -auth /var/run/gdm/auth-for-antoine-TLenrZ/database :61
antoine  11244 11242  0 12:26 ?        00:00:00 /bin/bash /usr/bin/xauth add :61 MIT-MAGIC-COOKIE-1 3a36497f58b026cd0e002585e3e17252

Comment 2 Miroslav Grepl 2012-09-10 05:53:45 UTC
Fixed in selinux-policy-3.10.0-149.fc17

Comment 3 Fedora Update System 2012-09-17 12:14:31 UTC
selinux-policy-3.10.0-149.fc17 has been submitted as an update for Fedora 17.

Comment 4 Fedora Update System 2012-09-19 02:56:05 UTC
Package selinux-policy-3.10.0-149.fc17:
* should fix your issue,
* was pushed to the Fedora 17 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing selinux-policy-3.10.0-149.fc17'
as soon as you are able to.
Please go to the following url:
then log in and leave karma (feedback).

Comment 5 Fedora Update System 2012-09-22 00:00:11 UTC
selinux-policy-3.10.0-149.fc17 has been pushed to the Fedora 17 stable repository.  If problems still persist, please make note of it in this bug report.

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