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== Summary ==
== Summary ==
All granting of privileged operations to ordinary users should be handled by centrally-managed system policy. Usermode/userhelper should be fully replaced by polkit in the future.
Access control of privileged operations for ordinary users should be handled ''exclusively'' by a centrally managed authority.  
 
Usermode/consolehelper should be phased out and be replaced entirely by polkit.


== Owner ==
== Owner ==
Line 10: Line 12:
* Name: [[User:Kay| Kay Sievers]]
* Name: [[User:Kay| Kay Sievers]]
* Email: kay@redhat.com
* Email: kay@redhat.com
* Name: [[User: Notting| Bill Nottingham]]
* Email: notting@redhat.com


== Current status ==
== Current status ==
* Targeted release: [[Releases/18 | Fedora 18 ]]
* Targeted release: [[Releases/20 | Fedora 20]]
* Last updated: 2012-04-03
* Last updated: 2013-03-20
* Percentage of completion: 20%
* Percentage of completion: 20%


== Detailed Description ==
== Detailed Description ==
The usermode/userhelper program is a setuid-root wrapper around a couple of tools, to provide superuser privileges to ordinary users. It’s policy is controlled by text files in /etc.
The usermode/consolehelper program is a setuid-root wrapper around a couple of system tools, providing superuser privileges to ordinary users. Its policy is controlled by text files in /etc.
 
These days, most privileged system operations are already controlled by polkit, a well-established, fine-grained, (possibly) network-transparent service for managing privileged operations by ordinary users. Enterprise environments need to be able to centrally define access control policy for the organization, and automatically apply it to all connected workstations.
 
* polkit can be used by privileged processes to decide if it should execute privileged operations on behalf of the requesting user. For directly executed tools, polkit provides a setuid-root helper program called ‘’pkexec’’.The hooks to ask the user for authorizations are well-integrated into text environments, and native in all major graphical environments.
* The concept of a ''console user''  (that usermode/consolehelper implements) is no longer a sufficient concept to derive privileges from. OTOH polkit authorizations can properly distinguish between multiple active sessions and seats: e.g. an untrusted user’s reboot request is only granted if only a single user session runs at that time.


Most system policy today is controlled by polkit, a well-established, fine-grained, possible network-transparent infrastructure to manage privileged operations by ordinary users. Polkit can be used by privileged process to decide if it should execute privileged operations on behalf of the requesting user. Polkit also provides a setuid-root helper program called pkexec, its callbacks to ask for authorizations are well-integrated into shell and graphical environments.
[http://www.freedesktop.org/software/polkit/docs/latest/polkit.8.html polkit(8) manual page]


== Benefit to Fedora ==
== Benefit to Fedora ==
<!-- What is the benefit to the platform?  If this is a major capability update, what has changed?  If this is a new feature, what capabilities does it bring? Why will Fedora become a better distribution or project because of this feature?-->
<!-- What is the benefit to the platform?  If this is a major capability update, what has changed?  If this is a new feature, what capabilities does it bring? Why will Fedora become a better distribution or project because of this feature?-->
 
* Consistency of system configuration.
* centrally managed policy, network-transparency possible
* Centralization of policy.
* polkit auth can distinguish between multiple sessions: e.g. untrusted user reboot request reboot only allowed when only a single user session runs
* Cleaner system integration; no implicit interception of tools residing in sbin/ with symlinks in bin/, which is less dependent on $PATH ordering.
* intercepting tools in sbin/ with tools in bin/ is considered bad practice; fewer dependencies on $PATH ordering
* No difference regarding the hookup between tools installed in bin/ or sbin/.


== Scope ==
== Scope ==
<!-- What work do the developers have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
<!-- What work do the developers have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->


* document how to convert consolehelper to polkit:
* Document how to convert consolehelper to polkit:
** python: put pkexec in the wrapper shell
** python: put a pkexec invocation in the wrapping shell script
** C tools: re-exec with pkexec in C code
** C tools: re-exec with pkexec in C code
** C tools: move original to /usr/lib/<pkg>/<tool>, and wrap /usr/bin/<tool> with a pkexec shell (ugly!)
** C tools: move original to /usr/lib/<pkg>/<tool>, and wrap /usr/bin/<tool> with a pkexec shell script (ugly!)
* open tracker bug and file bugs against all individual packages
* File bugs against all individual packages, and add them to tracker bug [https://bugzilla.redhat.com/show_bug.cgi?id=502765 502765]
* convert all packages, where it makes sense to use polkit, to pkexec
* Convert all packages where it makes sense to use polkit to pkexec.
* for the rest, drop usermode and recommend to use pkexec like sudo
* If all packages are successfully converted, userhelper may be removed


=== How to convert ===
=== How to Convert ===
A fast and easy way to convert a former consolehelper program is the use of pkexec.
A quick and easy way to convert a former consolehelper program is the use of pkexec.


As an example, we convert system-config-date to PolicyKit:
As an example we convert system-config-date to polkit:
<pre>
<pre>
# ls -l /usr/bin/system-config-date
# ls -l /usr/bin/system-config-date
Line 54: Line 64:
</pre>
</pre>


Ok, running /usr/bin/system-config-date would have executed /usr/share/system-config-date/system-config-date.py, so we create /usr/bin/system-config-date like the following:
OK, running /usr/bin/system-config-date would have executed /usr/share/system-config-date/system-config-date.py, so we create /usr/bin/system-config-date like the following:
<pre>
<pre>
# cat /usr/bin/system-config-date
# cat /usr/bin/system-config-date
Line 64: Line 74:
The important part is: <annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>
The important part is: <annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>


<code>/usr/share/polkit-1/actions/org.fedoraproject.config.date.policy</code>:
<pre>
<pre>
# cat /usr/share/polkit-1/actions/org.fedoraproject.config.date.policy
<?xml version="1.0" encoding="UTF-8"?>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE policyconfig PUBLIC
<!DOCTYPE policyconfig PUBLIC
Line 76: Line 86:


  <action id="org.fedoraproject.config.date.pkexec.run">
  <action id="org.fedoraproject.config.date.pkexec.run">
     <description>Run System Config Date</description>
     <_description>Run System Config Date</_description>
     <message>Authentication is required to run system-config-date</message>
     <_message>Authentication is required to run system-config-date</_message>
     <icon_name>system-config-date</icon_name>
     <icon_name>system-config-date</icon_name>
     <defaults>
     <defaults>
     <allow_any>no</allow_any>
     <allow_any>no</allow_any>
     <allow_inactive>no</allow_inactive>
     <allow_inactive>no</allow_inactive>
     <allow_active>auth_self_keep</allow_active>
     <allow_active>auth_admin_keep</allow_active>
     </defaults>
     </defaults>
     <annotate key="org.freedesktop.policykit.exec.path">/usr/share/system-config-date/system-config-date.py</annotate>
     <annotate key="org.freedesktop.policykit.exec.path">/usr/share/system-config-date/system-config-date.py</annotate>
Line 91: Line 101:


== How To Test ==
== How To Test ==
<!-- This does not need to be a full-fledged document.  Describe the dimensions of tests that this feature is expected to pass when it is done.  If it needs to be tested with different hardware or software configurations, indicate them.  The more specific you can be, the better the community testing can be.
<pre>
# yum remove usermode usermode-gtk
</pre>
should succeed for an installation with all Fedora packages installed.


Remember that you are writing this how to for interested testers to use to check out your feature - documenting what you do for testing is OK, but it's much better to document what *I* can do to test your feature.
<pre>
 
# repoquery --whatrequires usermode --whatrequires usermode-gtk
A good "how to test" should answer these four questions:
usermode-gtk-....
</pre>
should not output a single package, except the usermode-gtk package.


0. What special hardware / data / etc. is needed (if any)?
Make sure you can call all the tools which used to use usermode and are asked the appropriate authentication.
1. How do I prepare my system to test this feature? What packages
need to be installed, config files edited, etc.?
2. What specific actions do I perform to check that the feature is
working like it's supposed to?
3. What are the expected results of those actions?
-->
Make sure, you can call all the tools, which used to use usermode and be asked the appropriate password.


== User Experience ==
== User Experience ==
<!-- If this feature is noticeable by its target audience, how will their experiences change as a result?  Describe what they will see or notice. →
The user should experience no noticeable changes.
The user should experience no noticeable changes.


== Dependencies ==
== Dependencies ==
<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this feature depends?  In other words, completion of another feature owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel feature)? -->
<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this feature depends?  In other words, completion of another feature owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel feature)? -->
<pre>
* anaconda
anaconda
* audit-viewer
audit-viewer
* authconfig-gtk
authconfig-gtk
* backintime-gnome
backintime
* backintime-kde
beesu
* beesu
bootconf-gui
* bootconf-gui
chkrootkit
* chkrootkit
driftnet
* driftnet
drobo-utils-gui
* drobo-utils-gui
eclipse-oprofile
* eclipse-oprofile
ejabberd
* ejabberd
fwfstab
* fwfstab
galternatives
* galternatives
gnome-system-log
* gsmartcontrol
gsmartcontrol
* hddtemp
hddtemp
* kdenetwork-kppp
kdenetwork-kppp
* kismet
kismet
* liveusb-creator
liveusb-creator
* livna-config-display
lshw-gui
* lshw-gui
mock
* mock
mtr-gtk
* mtr-gtk
netgo
* netgo
nmap-frontend
* nmap-frontend
ntfs-config
* ntfs-config
policycoreutils-gui
* policycoreutils-gui
preupgrade
* preupgrade
pure-ftpd
* pure-ftpd
qtparted
* qtparted
revisor-cli
* realcrypt
rhn-setup
* revisor-cli
rhn-setup-gnome
* rhn-setup
sabayon
* rhn-setup-gnome
setools-gui
* sabayon
setuptool
* setools-gui
smart-gui
* setuptool
subscription-manager-gnome
* smart-gui
synaptic
* subscription-manager-gnome
system-config-audit
* synaptic
system-config-bind
* system-config-audit
system-config-boot
* system-config-bind
system-config-date
* system-config-boot
system-config-httpd
* system-config-date
system-config-kdump
* system-config-httpd
system-config-keyboard
* system-config-kdump
system-config-language
* system-config-keyboard
system-config-lvm
* system-config-language
system-config-nfs
* system-config-lvm
system-config-rootpassword
* system-config-network
system-config-users
* system-config-network-tui
system-switch-displaymanager
* system-config-nfs
system-switch-java
* system-config-rootpassword
system-switch-mail
* system-config-users
system-switch-mail-gnome
* system-switch-displaymanager
tuned
* system-switch-java
vpnc-consoleuser
* system-switch-mail
wifi-radar
* system-switch-mail-gnome
wlassistant
* tuned
xawtv
* usermode-gtk
yumex
* vpnc-consoleuser
zyx-liveinstaller
* wifi-radar
</pre>
* wlassistant
* xawtv
* yumex
* zyx-liveinstaller


== Contingency Plan ==
== Contingency Plan ==
<!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "None necessary, revert to previous release behaviour."  Or it might not.  If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy.  -->
<!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "None necessary, revert to previous release behaviour."  Or it might not.  If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy.  -->
Even, if we cannot drop usermode, the changes in the packages do not have to be reverted.
Even if we cannot drop usermode for F19 (because not all packages have been converted) the changes in the packages do not have to be reverted.


== Documentation ==
== Documentation ==
<!-- Is there upstream documentation on this feature, or notes you have written yourself?  Link to that material here so other interested developers can get involved. -->
* [http://www.freedesktop.org/wiki/Software/polkit polkit Homepage]
*
* [http://www.freedesktop.org/software/polkit/docs/latest/ polkit Documentation]
* [http://www.freedesktop.org/software/polkit/docs/latest/polkit.8.html polkit(8) manpage]
* [http://www.freedesktop.org/software/polkit/docs/latest/pkexec.1.html pkexec(1) manpage]


== Release Notes ==
== Release Notes ==
<!-- The Fedora Release Notes inform end-users about what is new in the release. Examples of past release notes are here: http://docs.fedoraproject.org/release-notes/ -->
 
<!-- The release notes also help users know how to deal with platform changes such as ABIs/APIs, configuration or data file formats, or upgrade concerns.  If there are any such changes involved in this feature, indicate them here.  You can also link to upstream documentation if it satisfies this need.  This information forms the basis of the release notes edited by the documentation team and shipped with the release. -->
* The following packages now use the polkit policy configuration instead of the usermode/consolehelper configuration. Please migrate any policy, which you have created for those packages. Documentation about polkit can be found on http://www.freedesktop.org/software/polkit/docs/latest/
*
 
  <list of packages>


== Comments and Discussion ==
== Comments and Discussion ==
* See [[Talk:Features/UsermodeMigration]] <!-- This adds a link to the "discussion" tab associated with your page.  This provides the ability to have ongoing comments or conversation without bogging down the main feature page -->
* See [[Talk:Features/UsermodeMigration]]
 


[[Category:FeaturePageIncomplete]]
[[Category:FeatureReadyForWrangler]]
<!-- When your feature page is completed and ready for review -->
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<!-- remove Category:FeaturePageIncomplete and change it to Category:FeatureReadyForWrangler -->
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Latest revision as of 13:48, 20 March 2013

Usermode Migration

Summary

Access control of privileged operations for ordinary users should be handled exclusively by a centrally managed authority.

Usermode/consolehelper should be phased out and be replaced entirely by polkit.

Owner

Current status

  • Targeted release: Fedora 20
  • Last updated: 2013-03-20
  • Percentage of completion: 20%

Detailed Description

The usermode/consolehelper program is a setuid-root wrapper around a couple of system tools, providing superuser privileges to ordinary users. Its policy is controlled by text files in /etc.

These days, most privileged system operations are already controlled by polkit, a well-established, fine-grained, (possibly) network-transparent service for managing privileged operations by ordinary users. Enterprise environments need to be able to centrally define access control policy for the organization, and automatically apply it to all connected workstations.

  • polkit can be used by privileged processes to decide if it should execute privileged operations on behalf of the requesting user. For directly executed tools, polkit provides a setuid-root helper program called ‘’pkexec’’.The hooks to ask the user for authorizations are well-integrated into text environments, and native in all major graphical environments.
  • The concept of a console user (that usermode/consolehelper implements) is no longer a sufficient concept to derive privileges from. OTOH polkit authorizations can properly distinguish between multiple active sessions and seats: e.g. an untrusted user’s reboot request is only granted if only a single user session runs at that time.

polkit(8) manual page

Benefit to Fedora

  • Consistency of system configuration.
  • Centralization of policy.
  • Cleaner system integration; no implicit interception of tools residing in sbin/ with symlinks in bin/, which is less dependent on $PATH ordering.
  • No difference regarding the hookup between tools installed in bin/ or sbin/.

Scope

  • Document how to convert consolehelper to polkit:
    • python: put a pkexec invocation in the wrapping shell script
    • C tools: re-exec with pkexec in C code
    • C tools: move original to /usr/lib/<pkg>/<tool>, and wrap /usr/bin/<tool> with a pkexec shell script (ugly!)
  • File bugs against all individual packages, and add them to tracker bug 502765
  • Convert all packages where it makes sense to use polkit to pkexec.
  • If all packages are successfully converted, userhelper may be removed

How to Convert

A quick and easy way to convert a former consolehelper program is the use of pkexec.

As an example we convert system-config-date to polkit: 

# ls -l /usr/bin/system-config-date
lrwxrwxrwx 1 root root 13  5. Feb 02:34 /usr/bin/system-config-date -> consolehelper

# rm /usr/bin/system-config-date
# cat /etc/security/console.apps/system-config-date
. config-util
PROGRAM=/usr/share/system-config-date/system-config-date.py
SESSION=true

OK, running /usr/bin/system-config-date would have executed /usr/share/system-config-date/system-config-date.py, so we create /usr/bin/system-config-date like the following: 

# cat /usr/bin/system-config-date
#!/bin/sh
exec /usr/bin/pkexec /usr/share/system-config-date/system-config-date.py

This will not export the DISPLAY variable, so we have to add a policy file, although starting a GUI as root is not encouraged. The important part is: <annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>

/usr/share/polkit-1/actions/org.fedoraproject.config.date.policy: 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE policyconfig PUBLIC
"-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
"http://www.freedesktop.org/standards/PolicyKit/1/policyconfig.dtd">
<policyconfig>

 <vendor>System Config Date</vendor>
 <vendor_url>http://fedorahosted.org/system-config-date</vendor_url>

 <action id="org.fedoraproject.config.date.pkexec.run">
    <_description>Run System Config Date</_description>
    <_message>Authentication is required to run system-config-date</_message>
    <icon_name>system-config-date</icon_name>
    <defaults>
     <allow_any>no</allow_any>
     <allow_inactive>no</allow_inactive>
     <allow_active>auth_admin_keep</allow_active>
    </defaults>
    <annotate key="org.freedesktop.policykit.exec.path">/usr/share/system-config-date/system-config-date.py</annotate>
    <annotate key="org.freedesktop.policykit.exec.allow_gui">true</annotate>
 </action>
</policyconfig>

How To Test

# yum remove usermode usermode-gtk

should succeed for an installation with all Fedora packages installed. 

# repoquery --whatrequires usermode --whatrequires usermode-gtk
usermode-gtk-....

should not output a single package, except the usermode-gtk package.

Make sure you can call all the tools which used to use usermode and are asked the appropriate authentication.

User Experience

The user should experience no noticeable changes.

Dependencies

  • anaconda
  • audit-viewer
  • authconfig-gtk
  • backintime-gnome
  • backintime-kde
  • beesu
  • bootconf-gui
  • chkrootkit
  • driftnet
  • drobo-utils-gui
  • eclipse-oprofile
  • ejabberd
  • fwfstab
  • galternatives
  • gsmartcontrol
  • hddtemp
  • kdenetwork-kppp
  • kismet
  • liveusb-creator
  • livna-config-display
  • lshw-gui
  • mock
  • mtr-gtk
  • netgo
  • nmap-frontend
  • ntfs-config
  • policycoreutils-gui
  • preupgrade
  • pure-ftpd
  • qtparted
  • realcrypt
  • revisor-cli
  • rhn-setup
  • rhn-setup-gnome
  • sabayon
  • setools-gui
  • setuptool
  • smart-gui
  • subscription-manager-gnome
  • synaptic
  • system-config-audit
  • system-config-bind
  • system-config-boot
  • system-config-date
  • system-config-httpd
  • system-config-kdump
  • system-config-keyboard
  • system-config-language
  • system-config-lvm
  • system-config-network
  • system-config-network-tui
  • system-config-nfs
  • system-config-rootpassword
  • system-config-users
  • system-switch-displaymanager
  • system-switch-java
  • system-switch-mail
  • system-switch-mail-gnome
  • tuned
  • usermode-gtk
  • vpnc-consoleuser
  • wifi-radar
  • wlassistant
  • xawtv
  • yumex
  • zyx-liveinstaller

Contingency Plan

Even if we cannot drop usermode for F19 (because not all packages have been converted) the changes in the packages do not have to be reverted.

Documentation

Release Notes

  • The following packages now use the polkit policy configuration instead of the usermode/consolehelper configuration. Please migrate any policy, which you have created for those packages. Documentation about polkit can be found on http://www.freedesktop.org/software/polkit/docs/latest/
 <list of packages>

Comments and Discussion

Retrieved from "https://fedoraproject.org/w/index.php?title=Features/UsermodeMigration&oldid=327070"