Features/UsermodeMigration

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(Retarget to Fedora 20 as agreed with Feature owner (lack of manpower for F19))
 
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== Summary ==
 
== Summary ==
All granting of privileged operations to ordinary users should exclusively be handled by centrally-managed polit policy. Usermode/userhelper should be phased-out and entirely replaced by polkit.
+
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. Its 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.
  
Most privileged user operations are already controlled by polkit today, a well-established, fine-grained, possible network-transparent infrastructure to manage privileged operations by ordinary users. Enterprise environments should be able to centrally define the domain’s policy, and automatically apply it to all connected workstations.
+
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 process to decide if it should execute privileged operations on behalf of the requesting user. The hooks to ask the user for authorizations are well-integrated into text, and natively into all major graphical environments.
+
* 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 auth can properly distinguish between multiple sessions: e.g. untrusted user reboot request reboot only allowed when only a single user session runs.
+
[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 configurat
+
* Consistency of system configuration.
 
+
* Centralization of policy.
* Polkit also provides a setuid-root helper program called pkexec. Pkexec’s
+
* 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/.
* intercepting tools in sbin/ with tools in bin/ is considered bad practice; fewer dependencies on $PATH ordering
+
 
+
  
 
== 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 60: 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 70: 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 82: 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 106: Line 110:
 
usermode-gtk-....
 
usermode-gtk-....
 
</pre>
 
</pre>
 
 
should not output a single package, except the usermode-gtk package.
 
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 be asked the appropriate password.
+
Make sure you can call all the tools which used to use usermode and are asked the appropriate authentication.
  
 
== User Experience ==
 
== User Experience ==
Line 116: Line 119:
 
== 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-gnome
+
* backintime-kde
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
+
* gsmartcontrol
gsmartcontrol
+
* hddtemp
hddtemp
+
* kdenetwork-kppp
kdenetwork-kppp
+
* kismet
kismet
+
* liveusb-creator
liveusb-creator
+
* livna-config-display
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
+
* realcrypt
realcrypt
+
* revisor-cli
revisor-cli
+
* rhn-setup
rhn-setup
+
* rhn-setup-gnome
rhn-setup-gnome
+
* sabayon
sabayon
+
* setools-gui
setools-gui
+
* setuptool
setuptool
+
* smart-gui
smart-gui
+
* subscription-manager-gnome
subscription-manager-gnome
+
* synaptic
synaptic
+
* system-config-audit
system-config-audit
+
* system-config-bind
system-config-bind
+
* system-config-boot
system-config-boot
+
* system-config-date
system-config-date
+
* system-config-httpd
system-config-httpd
+
* system-config-kdump
system-config-kdump
+
* system-config-keyboard
system-config-keyboard
+
* system-config-language
system-config-language
+
* system-config-lvm
system-config-lvm
+
* system-config-network
system-config-network
+
* system-config-network-tui
system-config-network-tui
+
* system-config-nfs
system-config-nfs
+
* system-config-rootpassword
system-config-rootpassword
+
* system-config-users
system-config-users
+
* system-switch-displaymanager
system-switch-displaymanager
+
* system-switch-java
system-switch-java
+
* system-switch-mail
system-switch-mail
+
* system-switch-mail-gnome
system-switch-mail-gnome
+
* tuned
tuned
+
* usermode-gtk
usermode-gtk
+
* vpnc-consoleuser
vpnc-consoleuser
+
* wifi-radar
wifi-radar
+
* wlassistant
wlassistant
+
* xawtv
xawtv
+
* yumex
yumex
+
* zyx-liveinstaller
zyx-liveinstaller
+
</pre>
+
  
 
== 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 -->
 
<!-- When your feature page is completed and ready for review -->
 
<!-- remove Category:FeaturePageIncomplete and change it to Category:FeatureReadyForWrangler -->
 
<!-- remove Category:FeaturePageIncomplete and change it to Category:FeatureReadyForWrangler -->
 
<!-- After review, the feature wrangler will move your page to Category:FeatureReadyForFesco... if it still needs more work it will move back to Category:FeaturePageIncomplete-->
 
<!-- After review, the feature wrangler will move your page to Category:FeatureReadyForFesco... if it still needs more work it will move back to Category:FeaturePageIncomplete-->
 
<!-- A pretty picture of the page category usage is at: https://fedoraproject.org/wiki/Features/Policy/Process -->
 
<!-- A pretty picture of the page category usage is at: https://fedoraproject.org/wiki/Features/Policy/Process -->

Latest revision as of 13:48, 20 March 2013

Contents

[edit] Usermode Migration

[edit] 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.

[edit] Owner

[edit] Current status

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

[edit] 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

[edit] 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/.

[edit] 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

[edit] 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>

[edit] 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.

[edit] User Experience

The user should experience no noticeable changes.

[edit] 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

[edit] 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.

[edit] Documentation

[edit] 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>

[edit] Comments and Discussion