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Bug 1285091 - xinetd attempts to bind to IPv6 sockets even on systems with IPv6 disabled
Summary: xinetd attempts to bind to IPv6 sockets even on systems with IPv6 disabled
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: xinetd
Version: 6.7
Hardware: All
OS: Linux
medium
medium
Target Milestone: rc
: ---
Assignee: Jan Synacek
QA Contact: Robin Hack
URL:
Whiteboard:
Depends On:
Blocks: 1270825
TreeView+ depends on / blocked
 
Reported: 2015-11-24 21:15 UTC by Karl Hastings
Modified: 2019-10-10 10:33 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2016-05-10 21:42:13 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
patch (753 bytes, patch)
2015-12-01 15:04 UTC, Jan Synacek 		no flags Details | Diff
View All


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2016:0851 0 normal SHIPPED_LIVE xinetd bug fix update 2016-05-10 22:43:32 UTC

Description Karl Hastings 2015-11-24 21:15:28 UTC 
Description of problem:
xinetd attempts to open sockets with PF_INET6 by default, even on systems with IPv6 module disabled ('options ipv6 disabled=1' in /etc/modprobe.d/*)

This causes xinetd to kill long running clients with xinetd is reloaded because xinetd appears to believe the config has changed for the service.

Version-Release number of selected component (if applicable):
xinetd-2.3.14-39.el6_4.x86_64

How reproducible:
100%

Steps to Reproduce:
1. enable telnet, or some other connection service in xinetd
2. disable IPv6 (blacklist the module, or options ipv6 disabled=1)
3. reboot
4. telnet (or connect to enabled service)
5. send SIGHUP (or 'service xinetd reload')


Actual results:
telnet connection is dropped because the telnet process receives SIGKILL

Expected results:
telnet connection stays up because telnet config didn't change

Additional info:
IPv6 by default was added in https://bugzilla.redhat.com/show_bug.cgi?id=195265

It looks like now if IPv6 is disabled xinetd gets confused thinking the running config doesn't match the defined service and will always send a SIGKILL (would send SIGTERM if the service were type = INTERNAL).  This is not desired behavior as the telnet (or whatever defined service) configuration has not changed.

Clarification was added to the man pages via: https://bugzilla.redhat.com/show_bug.cgi?id=1075152  but that misses the point.  The work-around would be to set 'flags = IPv4' to the service or 'bind = 0.0.0.0' to the main xinetd.conf   (as documented on our portal: https://access.redhat.com/solutions/706163 )  Maybe that should be added to the man page, as it is more relevant...

However customer feels that xinetd should handle this situation gracefully
Comment 4 Jan Synacek 2015-12-01 15:04:01 UTC 
Created attachment 1100938 [details]
patch
Comment 15 errata-xmlrpc 2016-05-10 21:42:13 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://rhn.redhat.com/errata/RHBA-2016-0851.html
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