Bug 1389059 - sudo hangs after entering password when using NIS ypbind client
Summary: sudo hangs after entering password when using NIS ypbind client
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: sudo
Version: 7.2
Hardware: x86_64
OS: Linux
unspecified
low
Target Milestone: rc
: ---
Assignee: Daniel Kopeček
QA Contact: BaseOS QE Security Team
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2016-10-26 18:18 UTC by John Sopko
Modified: 2016-11-10 09:51 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: If docs needed, set a value
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Clone Of:
Environment:
Last Closed: 2016-11-10 09:51:18 UTC
Target Upstream Version:

Attachments (Terms of Use)
sudo debug output (93.63 KB, text/plain)
2016-10-27 19:59 UTC, John Sopko 		no flags Details
View All Add an attachment (proposed patch, testcase, etc.)

Description John Sopko 2016-10-26 18:18:50 UTC 
Description of problem:

Using sudo on rhel7.2 with NIS/ypbind hangs after password is entered. We use NIS, on rhel6.8 servers, to supply password login info and kerberos for authentication. Putting an entry in the local /etc/passwd, (no shadow entry), fixes the issue.

Using tcpdump it appears sudo is requesting nis info from the server over and over but hangs. Red Hat 5,6 Ubuntu 12.04, 14.04 and 16.04 work fine.

Turning sudo Debug on does not log anything. No clues in /var/log/secure or messages logs.


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

Sudo version 1.8.6p7


How reproducible:

Always


Steps to Reproduce:
1. try to do sudo command
2.
3.

Actual results:

sudo not to hang

Expected results:

sudo hangs

Additional info:

Here is the /etc/nsswitch.conf config, nothing fancy:

passwd:     files nis
shadow:     files
group:      files nis
Comment 2 John Sopko 2016-10-27 19:56:42 UTC 
I got debugging working by setting:

Debug sudo /var/log/sudo_debug all@debug
Debug sudoers.so /var/log/sudo_debug all@debug

Instead of the default all@warn. I do no see any clues in the debug log. I attached the debug output log. I also copied over the sudo executable from rhel 6.8 and tried it, it also hung.
Comment 3 John Sopko 2016-10-27 19:59:04 UTC 
Created attachment 1214734 [details]
sudo debug output

Debug output from single sudo session that hangs.
Comment 4 John Sopko 2016-10-27 20:01:56 UTC 
One more item, if I enter an incorrect passwd sudo does not hang and comes back to enter the passwd again. So it appears it is not hanging on authentication to the kerberos that we use.
Comment 5 John Sopko 2016-11-09 16:25:17 UTC 
I updated to RHEL 7.3 and sudo now works. This bug can be closed.
Comment 6 Daniel Kopeček 2016-11-10 09:51:18 UTC 
(In reply to John Sopko from comment #5)
> I updated to RHEL 7.3 and sudo now works. This bug can be closed.

Thanks for the info. Closing.
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