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Bug 1684979 - The HBAC code requires dereference to be enabled and fails otherwise
Summary: The HBAC code requires dereference to be enabled and fails otherwise
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: sssd
Version: 7.6
Hardware: All
OS: Linux
unspecified
high
Target Milestone: rc
: ---
Assignee: SSSD Maintainers
QA Contact: ipa-qe
URL:
Whiteboard:
Depends On:
Blocks: 1684981
TreeView+ depends on / blocked
 
Reported: 2019-03-04 04:09 UTC by Ahmed Nazmy
Modified: 2020-05-02 19:08 UTC (History)
10 users (show)

Fixed In Version: sssd-1.16.4-14.el7
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
: 1684981 (view as bug list)
Environment:
Last Closed: 2019-08-06 13:02:47 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Github SSSD sssd issues 4951 0 None closed The HBAC code requires dereference to be enabled and fails otherwise 2020-10-20 07:43:52 UTC
Red Hat Product Errata RHSA-2019:2177 0 None None None 2019-08-06 13:03:05 UTC

Description Ahmed Nazmy 2019-03-04 04:09:32 UTC 
Description of problem:

In some situations we recommend "ldap_deref_threshold=0" setting for sssd for performance enhancement.

This setting when applied breaks ssh access to IdM clients, as it seems sssd's HBAC code doesn't work when de-reference is disabled.



Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1. enroll a machine to and IdM domain
2. set "ldap_deref_threshold=0" in sssd.conf and restart sssd
3. try to ssh to this machine


Actual results:

SSH access fails and errors similar to the below is captured on sssd debug logs:
~~~
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_parse_range] (0x2000): No sub-attributes for [objectClass]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_parse_range] (0x2000): No sub-attributes for [cn]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_parse_range] (0x2000): No sub-attributes for [fqdn]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_parse_range] (0x2000): No sub-attributes for [serverHostname]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_parse_range] (0x2000): No sub-attributes for [ipaSshPubKey]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_parse_range] (0x2000): No sub-attributes for [ipaUniqueID]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_process_result] (0x2000): Trace: sh[0x55a082395c50], connected[1], ops[0x55a0823cfab0], ldap[0x55a08238ae60]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_process_message] (0x4000): Message type: [LDAP_RES_SEARCH_RESULT]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_get_generic_op_finished] (0x0400): Search result: Success(0), no errmsg set
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_get_generic_op_finished] (0x2000): Total count [0]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_op_destructor] (0x2000): Operation 28 finished
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [ipa_host_info_done] (0x0020): Server does not support deref
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_id_op_destroy] (0x4000): releasing operation connection
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [ipa_pam_access_handler_done] (0x0020): Unable to fetch  rules [5]: Input/output error
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [dp_req_done] (0x0400): DP Request [PAM Account #7]: Request handler finished [0]: Success
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [_dp_req_recv] (0x0400): DP Request [PAM Account #7]: Receiving request data.
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [dp_req_destructor] (0x0400): DP Request [PAM Account #7]: Request removed.
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [dp_req_destructor] (0x0400): Number of active DP request: 0
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [dp_pam_reply] (0x1000): DP Request [PAM Account #7]: Sending result [4][example.com]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_process_result] (0x2000): Trace: sh[0x55a082395c50], connected[1], ops[(nil)], ldap[0x55a08238ae60]
(Sun Feb 24 14:27:03 2019) [sssd[be[example.com]]] [sdap_process_result] (0x2000): Trace: end of ldap_result list
~~~

Expected results:

SSH access works fine (honoring HBAC rules) while derefrence control is set to zero.

Additional info:
Comment 3 thierry bordaz 2019-03-04 08:20:06 UTC 
Just for recording, in case SSSD requires to use deref control and hit performance issue (long lasting ldap req) then we could investigate an improvement on DS side https://pagure.io/389-ds-base/issue/49951
Comment 4 Jakub Hrozek 2019-03-06 21:46:57 UTC 
Upstream ticket:
https://pagure.io/SSSD/sssd/issue/3979
Comment 6 Jakub Hrozek 2019-03-27 20:37:39 UTC 
* master:
  * 9d63616
  * 1eb3ae1
* sssd-1-16:
  * 2c97edb
  * eaceb6a
Comment 12 Sumedh Sidhaye 2019-05-17 12:10:07 UTC 
Build used for verification:

[root@ipaqavmh ~]# rpm -qa ipa-server sssd
ipa-server-4.6.5-8.el7.x86_64
sssd-1.16.4-13.el7.x86_64
[root@ipaqavmh ~]# 


Since I am still seeing authentication failures, after adding ldap_deref_threshold=0
Marking BZ failed QA
Comment 14 Sumedh Sidhaye 2019-05-20 09:16:17 UTC 
Verification procedure


On Server
[root@ipaqavmh ~]# rpm -qa ipa-* sssd
ipa-server-4.6.5-8.el7.x86_64
ipa-server-common-4.6.5-8.el7.noarch
ipa-client-4.6.5-8.el7.x86_64
sssd-1.16.4-14.el7.x86_64
ipa-common-4.6.5-8.el7.noarch
ipa-client-common-4.6.5-8.el7.noarch
ipa-server-dns-4.6.5-8.el7.noarch
[root@ipaqavmh ~]# 

[root@ipaqavmh ~]# grep -nr "ldap_deref_threshold=0" /etc/sssd/sssd.conf
14:ldap_deref_threshold=0
[root@ipaqavmh ~]# 

[root@ipaqavmh ~]# ipa hbacrule-find
--------------------
2 HBAC rules matched
--------------------
  Rule name: allow_all
  User category: all
  Host category: all
  Service category: all
  Description: Allow all users to access any host from any host
  Enabled: TRUE

  Rule name: allow_systemd-user
  User category: all
  Host category: all
  Description: Allow pam_systemd to run user@.service to create a system user session
  Enabled: TRUE
----------------------------
Number of entries returned 2
----------------------------
[root@ipaqavmh ~]# 


[root@ipaqavmh ~]# ipa user-add testuser2 --first test --last user2 --password
Password: 
Enter Password again to verify: 
----------------------
Added user "testuser2"
----------------------
  User login: testuser2
  First name: test
  Last name: user2
  Full name: test user2
  Display name: test user2
  Initials: tu
  Home directory: /home/testuser2
  GECOS: test user2
  Login shell: /bin/sh
  Principal name: testuser2
  Principal alias: testuser2
  User password expiration: 20190520081820Z
  Email address: testuser2
  UID: 1737200003
  GID: 1737200003
  Password: True
  Member of groups: ipausers
  Kerberos keys available: True

##################################################################

On Client

[root@ipaqavmc ~]# rpm -qa ipa-* sssd
ipa-client-4.6.5-8.el7.x86_64
sssd-1.16.4-14.el7.x86_64
ipa-common-4.6.5-8.el7.noarch
ipa-client-common-4.6.5-8.el7.noarch
[root@ipaqavmc ~]# 

[root@ipaqavmc ~]# ssh testuser2.test
Password: 
Password expired. Change your password now.
Current Password: 
Password change failed. Server message: Old password not accepted.

Password: 
Password: 
Password expired. Change your password now.
Current Password: 
New password: 
Retype new password: 
Last failed login: Mon May 20 04:20:36 EDT 2019 from ipaqavmc.idmqe.lab.eng.bos.redhat.com on ssh:notty
There were 2 failed login attempts since the last successful login.
-sh-4.2$ 
-sh-4.2$ whoami
testuser2


Based on above observations, marking the bugzilla verified.
Comment 17 errata-xmlrpc 2019-08-06 13:02:47 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.

https://access.redhat.com/errata/RHSA-2019:2177
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