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Revision as of 16:06, 17 January 2012 by Dwalsh (Talk | contribs)

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Feature Name

Change several dangerous domains to use PrivateTmp in their unit file.


Run some services started by systemd with a private /tmp directory. This would mitigate the chance of a service making a mistake with how it handles its /tmp data allowing a user on the system to get a privilege escalation, since users would not have access to the services /tmp directory.


  • Email: dwalsh@redhat.com

Current status

  • Targeted release: [Fedora 17]
  • Last updated: Tue Jan 17 2012
  • Percentage of completion: 75%

Detailed Description

It seems to be a weekly occurrence of a new CVE for some app that uses /tmp insecurely.

Privileged services should stop using /tmp and /var/tmp. These services can potentially be interfered by unprivileged users, potentially leading to process escalation. The only server applications that need to use /tmp should be for communicating with users. For example the X server, and potentially apps that use kerberos for example sssd and nfs.gssd. (Although maybe at some point we need to fix this.) Most apps that rely on using /tmp to communicate with the user can be easily broken by users having individual /tmp using pam_namespace.

systemd as of Fedora 16 has the ability to run system services with private /tmp and /var/tmp. I would like to propose that we make this the default in Fedora 17, or at least open a bugzilla on all system services that we know of that use /tmp and /var/tmp to make them use private /tmp and /var/tmp.

Benefit to Fedora

Fedora systems would be more secure, and mitigated against /tmp privilege escalation.


This bugzilla is a blocker on all services that need to change their service unit file to include PrivateTmp=True


How To Test

Administrators that expect to find services /tmp data in /tmp will have to look in a new location. Sharing data via /tmp from a user to a system service or vice versa might be broken.


Release Notes

Comments and Discussion