Bug 469389 - Any user can send dbus messages to gdm that start a new X session
Any user can send dbus messages to gdm that start a new X session
Product: Fedora
Classification: Fedora
Component: gdm (Show other bugs)
All Linux
medium Severity medium
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Assigned To: jmccann
Fedora Extras Quality Assurance
: Triaged
Depends On:
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Reported: 2008-10-31 12:01 EDT by Kostas Georgiou
Modified: 2015-01-14 18:21 EST (History)
6 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2009-12-18 01:42:41 EST
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RHEL 7.3 requirements from Atomic Host:
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Attachments (Terms of Use)
example "exploit" (328 bytes, text/x-python)
2008-10-31 12:03 EDT, Kostas Georgiou
no flags Details

  None (edit)
Description Kostas Georgiou 2008-10-31 12:01:54 EDT
Any local user can call CreateTransientDisplay on the org.gnome.DisplayManager.LocalDisplayFactory interface which results in a new X session. 

Beyond that this will annoy the hell out of whoever is on the local machine I suspect that a loop that keeps sending the message can be an effective DOS.
Comment 1 Kostas Georgiou 2008-10-31 12:03:53 EDT
Created attachment 322103 [details]
example "exploit"
Comment 2 Ray Strode [halfline] 2008-10-31 14:04:03 EDT
So at a minimum we should modify the dbus security policy in /etc/dbus-1/system.d to only allow at_console users to run it, but really we should be using policykit to levy access.
Comment 3 Tomas Hoger 2008-11-03 06:26:39 EST
Is this interface used to spawn another local session when some user is already logged-in in X?  If so, restricting this to console users only sounds good.  I'm not sure how PolicyKit is expected to be used here.
Comment 4 Kostas Georgiou 2008-11-14 12:40:16 EST
I at least have no idea at all as to what is using this interface. Probably just fast user switching but you never know.

I am not sure that I want my users to be able to start an unlimited amount of X servers even if they are in the console to tell the truth but this is a different story I guess.
Comment 5 Bug Zapper 2008-11-25 23:33:38 EST
This bug appears to have been reported against 'rawhide' during the Fedora 10 development cycle.
Changing version to '10'.

More information and reason for this action is here:
Comment 6 Bug Zapper 2009-11-18 03:43:10 EST
This message is a reminder that Fedora 10 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
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Comment 7 Bug Zapper 2009-12-18 01:42:41 EST
Fedora 10 changed to end-of-life (EOL) status on 2009-12-17. Fedora 10 is 
no longer maintained, which means that it will not receive any further 
security or bug fix updates. As a result we are closing this bug.

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