864889 – Configure winbind_krb5_locator.so via alternatives to allow IPA AD trusts use

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Bug 864889 - Configure winbind_krb5_locator.so via alternatives to allow IPA AD trusts use

Summary: Configure winbind_krb5_locator.so via alternatives to allow IPA AD trusts use

Keywords:
Status:	CLOSED ERRATA
Alias:	None
Product:	Red Hat Enterprise Linux 6
Classification:	Red Hat
Component:	samba4
Sub Component:
Version:	6.4
Hardware:	Unspecified
OS:	Unspecified
Priority:	unspecified
Severity:	unspecified
Target Milestone:	rc
Target Release:	---
Assignee:	Andreas Schneider
QA Contact:	Namita Soman
Docs Contact:
URL:
Whiteboard:
Depends On:
Blocks:	864950
TreeView+	depends on / blocked

Reported:	2012-10-10 10:50 UTC by Alexander Bokovoy
Modified:	2013-02-21 08:36 UTC (History)
CC List:	3 users (show)
Fixed In Version:	samba4-4.0.0-52.el6.rc4
Doc Type:	Bug Fix
Doc Text:
Clone Of:
Clones:	864950 (view as bug list)
Environment:
Last Closed:	2013-02-21 08:36:35 UTC
Target Upstream Version:
Embargoed:

Attachments	(Terms of Use)
patch to introduce alternatives for winbind_krb5_locator.so (2.94 KB, patch) 2012-10-10 10:54 UTC, Alexander Bokovoy	no flags	Details \| Diff
View All

Links
System	ID	Private	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2013:0506	0	normal	SHIPPED_LIVE	Moderate: samba4 security, bug fix and enhancement update	2013-02-20 21:30:25 UTC

Description Alexander Bokovoy 2012-10-10 10:50:48 UTC

Description of problem:
On IPA server when AD trusts feature is enabled, winbind_krb5_locator.so plugin should not be available to libkrb5. This could be achieved by requiring that samba{,4}-winbind-krb5-locator package is never installed when ipa-server-trust-ad package is installed but much easier to automatically configure through alternatives.

Without this fix winbind_krb5_locator.so plugin to libkrb5 will interfere with winbindd configuration for IPA AD trusts, rendering them unusable.

Comment 2 Alexander Bokovoy 2012-10-10 10:54:22 UTC

Created attachment 624780 [details]
patch to introduce alternatives for winbind_krb5_locator.so

This is spec change that is needed to allow disabling winbind_krb5_locator.so plugin when trusts are in use on the server. Since libkrb5 reads any file in its plugins directory, keeping disabled plugin there is not an option, so I moved it back to %_libdir and used alternatives instead.

When trusts package (ipa-server-trust-ad) is installed, it will alternate to /dev/null for this plugin (link in plugins dir will point to /etc/alternatives/winbind_krb5_locator.so which will point to /dev/null). This will make libkrb5 to effectively ignore the plugin.

When trusts package is uninstalled, samba4 package will automatically be selected as a provider for the winbind_krb5_locator.so and will redirect the link to %_libdir/winbind_krb5_locator.so which is happily used by libkrb5

Comment 4 Andreas Schneider 2012-12-06 16:49:55 UTC

There is a typo in post uninstall script.

Comment 5 Andreas Schneider 2012-12-10 18:08:07 UTC

Fixed postun script.

Comment 7 Andreas Schneider 2012-12-17 11:21:28 UTC

Fixed another typo in postun script.

Comment 8 Namita Soman 2013-01-28 16:17:55 UTC

Installed ipa-server-trust-ad, and verified the 
# yum install ipa-server-trust-ad

# find / -name winbind_krb5_locator.so -print 
/var/lib/alternatives/winbind_krb5_locator.so
/usr/lib64/krb5/plugins/libkrb5/winbind_krb5_locator.so
/etc/alternatives/winbind_krb5_locator.so

# ls -l /usr/lib64/krb5/plugins/libkrb5/winbind_krb5_locator.so
lrwxrwxrwx. 1 root root 41 Jan 28 11:08 /usr/lib64/krb5/plugins/libkrb5/winbind_krb5_locator.so -> /etc/alternatives/winbind_krb5_locator.so


Next uninstalled ipa-server-ad....
# yum remove ipa-server-trust-ad

# find / -name winbind_krb5_locator.so -print 
<Nothing listed>


Ques: Does this verify the bz? Not sure how to verify the part "When trusts package is uninstalled, samba4 package will automatically be selected as a provider for the winbind_krb5_locator.so and will redirect the link to %_libdir/winbind_krb5_locator.so which is happily used by libkrb5"

Comment 9 Andreas Schneider 2013-01-28 17:14:49 UTC

There is also a samba4-winbind-krb5-locator plugin. If you install samba4-winbind-krb5-locator and ipa-server-trust-ad then the locator plugin should be the one from IPA.


If both are installed and you uninstall ipa-server-trust-ad the samba4-winbind-krb5-locator plugin should be linked again.

Comment 10 Namita Soman 2013-01-28 18:29:44 UTC

# rpm -qa | grep samba
samba4-common-4.0.0-55.el6.rc4.x86_64
samba4-python-4.0.0-55.el6.rc4.x86_64
samba4-libs-4.0.0-55.el6.rc4.x86_64
samba4-winbind-4.0.0-55.el6.rc4.x86_64
samba4-4.0.0-55.el6.rc4.x86_64
samba4-winbind-krb5-locator-4.0.0-55.el6.rc4.x86_64


After uninstalling ipa-server-trust-ad:
# ls -l /usr/lib64/krb5/plugins/libkrb5/winbind_krb5_locator.so
lrwxrwxrwx. 1 root root 41 Jan 28 13:26 /usr/lib64/krb5/plugins/libkrb5/winbind_krb5_locator.so -> /etc/alternatives/winbind_krb5_locator.so

Comment 11 Namita Soman 2013-01-28 18:34:38 UTC

With ipa-server-trust-ad and samba4-winbind-krb5-locator installed, then uninstalled ipa-server-trust-ad....

# find / -name winbind_krb5_locator.so -print 
/var/lib/alternatives/winbind_krb5_locator.so
/usr/lib64/krb5/plugins/libkrb5/winbind_krb5_locator.so
/usr/lib64/winbind_krb5_locator.so
/etc/alternatives/winbind_krb5_locator.so

# ls -l /usr/lib64/winbind_krb5_locator.so
-rwxr-xr-x. 1 root root 6000 Jan 23 05:55 /usr/lib64/winbind_krb5_locator.so

# ls -l /usr/lib64/krb5/plugins/libkrb5/winbind_krb5_locator.so
lrwxrwxrwx. 1 root root 41 Jan 28 13:26 /usr/lib64/krb5/plugins/libkrb5/winbind_krb5_locator.so -> /etc/alternatives/winbind_krb5_locator.so

Comment 12 errata-xmlrpc 2013-02-21 08:36:35 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2013-0506.html

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