Bug 805918

Summary: Wrong resolv_status might cause crash when name resolution times out
Product: Red Hat Enterprise Linux 6 Reporter: Dmitri Pal <dpal>
Component: sssdAssignee: Stephen Gallagher <sgallagh>
Status: CLOSED ERRATA QA Contact: IDM QE LIST <seceng-idm-qe-list>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 6.3CC: grajaiya, jgalipea, jhrozek, kbanerje, prc
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: sssd-1.8.0-20.el6 Doc Type: Bug Fix
Doc Text:
No documentation needed.
Story Points: ---
Clone Of: Environment:
Last Closed: 2012-06-20 11:56:28 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Description Dmitri Pal 2012-03-22 12:58:19 UTC
This bug is created as a clone of upstream ticket:
https://fedorahosted.org/sssd/ticket/1274

When name resolution times out, the errno return code is 110 (which is correct = ETIMEDOUT), but the resolv_status is 0. This is wrong.

We should probably rely mostly on the errno return code and only treat the resolv_status, which is the original ares return code, as kind of extended information, also because in the future we might switch to a different resolver with different error codes.

Comment 1 Jenny Severance 2012-03-22 19:59:07 UTC
Please add steps to verify this issue

Comment 2 Jakub Hrozek 2012-03-27 21:49:52 UTC
(In reply to comment #1)
> Please add steps to verify this issue

I'm going to write a unit test that exercises this part of the resolver code. Other than that, setting up a DROP rule on a machine that runs the DNS server should trigger the timeout as well.

Comment 5 Jakub Hrozek 2012-04-03 18:50:22 UTC
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
No documentation needed.

Comment 6 Kaushik Banerjee 2012-04-16 14:05:23 UTC
Verified in version:
# rpm -qi sssd | head
Name        : sssd                         Relocations: (not relocatable)
Version     : 1.8.0                             Vendor: Red Hat, Inc.
Release     : 22.el6                        Build Date: Mon 09 Apr 2012 07:40:33 PM IST
Install Date: Mon 16 Apr 2012 04:57:02 PM IST      Build Host: x86-003.build.bos.redhat.com
Group       : Applications/System           Source RPM: sssd-1.8.0-22.el6.src.rpm
Size        : 7870660                          License: GPLv3+
Signature   : (none)
Packager    : Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>
URL         : http://fedorahosted.org/sssd/
Summary     : System Security Services Daemon


Steps to verify:

1. Add a drop rule(drop on 53 udp port) on the DNS Server.
2. Lookup a user.

With the patched version(1.8.0-22) I see the following in the logs:

[resolv_gethostbyname_done] (0x0040): querying hosts database failed [110]: Connection timed out
[fo_resolve_service_done] (0x0020): Failed to resolve server 'server1.example.com': Timeout while contacting DNS servers
[be_resolve_server_done] (0x0080): Couldn't resolve server (server1.example.com), resolver returned (110)


With the unpatched version, the log shows:

[resolv_gethostbyname_done] (0x0040): querying hosts database failed [110]: Connection timed out
[fo_resolve_service_done] (0x0020): Failed to resolve server 'server1.example.com': Successful completion
[be_resolve_server_done] (0x1000): Saving the first resolved server
[be_resolve_server_done] (0x0020): FATAL: No hostent available for server (server1.example.com)
[be_resolve_server_done] (0x1000): Server resolution failed: 14

Comment 8 errata-xmlrpc 2012-06-20 11:56:28 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/RHBA-2012-0747.html