RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1845596 - ipa trust-add fails with 'Fetching domains from trusted forest failed'
Summary: ipa trust-add fails with 'Fetching domains from trusted forest failed'
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: ipa
Version: 8.3
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: 8.0
Assignee: Thomas Woerner
QA Contact: ipa-qe
URL:
Whiteboard:
Depends On: 1853432 1869311
Blocks: 1842946
TreeView+ depends on / blocked
 
Reported: 2020-06-09 15:27 UTC by anuja
Modified: 2020-11-04 02:51 UTC (History)
5 users (show)

Fixed In Version: ipa-4.8.7-7
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2020-11-04 02:51:04 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Fedora Pagure freeipa issue 8395 0 None None None 2020-07-02 16:16:13 UTC

Description anuja 2020-06-09 15:27:12 UTC 
Description of problem:
ipa trust-add fails with Fetching domains from trusted forest failed

Version-Release number of selected component (if applicable):
ipa-server-4.8.6-2.module+el8.3.0+6878+7463afe6.x86_64

How reproducible:
Always

Steps to Reproduce:
1.Setup ipa-server
2.Establish trust with IPA server 

Actual results:
ipa: ERROR: error on server 'master.ipa.test': Fetching domains from trusted forest failed. See details in the error_log

Expected results:
It should be working successfully.
Comment 1 Alexander Bokovoy 2020-06-09 16:26:32 UTC 
Logs are required to perform analysis.
Comment 4 Alexander Bokovoy 2020-07-02 16:12:06 UTC 
The core of the issue is an AVC that is marked as don't audit in SELinux policy.

When starting the helper to retrieve information about trusted domains, oddjobd uses `execve()` function. 
It looks like in RHEL 8.3 and Fedora 32 its processing on a transition between oddjob_t and ipa_helper_t SELinux domains breaks something in underlying libraries loaded by the IPA helper. The helper written in Python and uses bindings to Samba which also internally load libkrb5.

With disabled dontaudit SELinux rules we see following AVCs:

type=AVC msg=audit(1593698019.970:2915): avc:  denied  { noatsecure } for  pid=33476 comm="oddjobd" scontext=system_u:system_r:oddjob_t:s0-s0:c0.c1023 tcontext=system_u:system_r:ipa_helper_t:s0 tclass=process permissive=1
type=AVC msg=audit(1593698019.971:2916): avc:  denied  { rlimitinh } for  pid=33476 comm="com.redhat.idm." scontext=system_u:system_r:oddjob_t:s0-s0:c0.c1023 tcontext=system_u:system_r:ipa_helper_t:s0 tclass=process permissive=1
type=AVC msg=audit(1593698019.971:2917): avc:  denied  { siginh } for  pid=33476 comm="com.redhat.idm." scontext=system_u:system_r:oddjob_t:s0-s0:c0.c1023 tcontext=system_u:system_r:ipa_helper_t:s0 tclass=process permissive=1
type=AVC msg=audit(1593698022.000:2918): avc:  denied  { read } for  pid=33479 comm="ipa-getkeytab" name="config" dev="vda1" ino=156614 scontext=system_u:system_r:ipa_helper_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file permissive=1
type=AVC msg=audit(1593698022.001:2919): avc:  denied  { open } for  pid=33479 comm="ipa-getkeytab" path="/etc/selinux/config" dev="vda1" ino=156614 scontext=system_u:system_r:ipa_helper_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file permissive=1
type=AVC msg=audit(1593698022.001:2920): avc:  denied  { getattr } for  pid=33479 comm="ipa-getkeytab" path="/etc/selinux/config" dev="vda1" ino=156614 scontext=system_u:system_r:ipa_helper_t:s0 tcontext=system_u:object_r:selinux_config_t:s0 tclass=file permissive=1

Out of these, rlimitinh and siginh can be ignored but noatsecure denial is important. If it is allowed, the helper successfully does it work. If it is denied, Samba Python bindings could not properly initialize Kerberos principal from the current credentials cache. It should be a trusted domain object's principal from an Active Directory domain's realm but it is initialized as a principal from IPA's own realm. The difference might be subtle but the consequence is that the helper would request a cross-realm referral to Active Directory domain, effectively asking for an outgoing trust leg. However, this trust leg will not exist for a one-way trust and the whole processing will fail.

Once noatsecure was allowed, libkrb5 was able to import the Kerberos principal with Active Directory domain's realm and avoid asking for a cross-realm referral. Instead, it talked directly to AD DCs, avoiding the whole problem.

To fix this, we need two changes:
 1. An extension of IPA SELinux policy: https://github.com/freeipa/freeipa/pull/4882
 2. Use of IPA SElinux policy interface in oddjob SELinux policy: https://github.com/fedora-selinux/selinux-policy-contrib/pull/293
Comment 5 Alexander Bokovoy 2020-07-06 08:27:13 UTC 
Both IPA and SELinux changes merged in the upstreams

Fixed upstream FreeIPA:
master:
https://pagure.io/freeipa/c/f6055e6c9f6e88f8174c3bc920ff46583a14822f
https://pagure.io/freeipa/c/91713f4f0a1033943ccf949fb3bfed2447e3ea0f

Merged upstream SELinux:
master:
https://github.com/fedora-selinux/selinux-policy-contrib/commit/2b8b6241d3de33a28fe1acdd35974e2197d03a6e
Comment 6 Alexander Bokovoy 2020-07-06 09:33:35 UTC 
Fixed upstream
ipa-4-8:
https://pagure.io/freeipa/c/42dd1628a1211363c860917e474ecc5b9c1fdb84
https://pagure.io/freeipa/c/0d70addbbf2a99e7398a518bc98d5fe109469bb5
Comment 13 errata-xmlrpc 2020-11-04 02:51:04 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 (Moderate: idm:DL1 and idm:client security, bug fix, and enhancement update), and where to find the updated
files, follow the link below.

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

https://access.redhat.com/errata/RHSA-2020:4670
Note You need to log in before you can comment on or make changes to this bug.