Bug 1320596 – glibc: NULL pointer dereference in stub resolver with unconnectable name server addresses

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Bug 1320596 - glibc: NULL pointer dereference in stub resolver with unconnectable name server addresses

Summary:	glibc: NULL pointer dereference in stub resolver with unconnectable name serv...

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 7
Classification:	Red Hat
Component:	glibc (Show other bugs)
Sub Component:
Version:	7.3
Hardware:	Unspecified Unspecified

Priority	high Severity medium
Target Milestone:	rc
Target Release:	---
Assigned To:	Florian Weimer
QA Contact:	Michael Petlan
Docs Contact:

URL:
Whiteboard:
Keywords:	Patch, ZStream

Depends On:	1316972
Blocks:	1323839
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Reported:	2016-03-23 11:24 EDT by Florian Weimer
Modified:	2016-11-03 04:31 EDT (History)
CC List:	10 users (show)

See Also:
Fixed In Version:
Doc Type:	No Doc Update
Doc Text:	undefined
Story Points:	---
Clone Of:	1316972
Clones:	1323839 (view as bug list)
Environment:
Last Closed:	2016-11-03 04:31:14 EDT
Type:	Bug
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Sourceware	19791	None	None	None	2016-03-23 11:24 EDT
Sourceware	19825	None	None	None	2016-03-23 11:24 EDT
Sourceware	19830	None	None	None	2016-03-23 11:24 EDT
Sourceware	19831	None	None	None	2016-03-23 11:24 EDT
Red Hat Product Errata	RHSA-2016:2573	normal	SHIPPED_LIVE	Low: glibc security, bug fix, and enhancement update	2016-11-03 08:05:56 EDT

Groups: None (edit)

Description Florian Weimer 2016-03-23 11:24:21 EDT

+++ This bug was initially created as a clone of Bug #1316972 +++

If /etc/resolv.conf contains addresses which cause the connect system call to fail immediately, queries which trigger search along the search path result in a segmentation fault.

A workaround is to remove the problematic addresses from /etc/resolv.conf.

--- Additional comment from Florian Weimer on 2016-03-23 16:22:08 CET ---

swbz#19825 is a very similar bug in send_vc/TCP (the original bug is about send_dg/UDP), so far only observed under valgrind.

swbz#19831 and swbz#19830 should be backported as well, to get cleaner test suite runs.

Comment 2 Florian Weimer 2016-03-31 04:23:26 EDT

Test case for the assert/NULL pointer dereference:

  https://pagure.io/glibc-resolv-tests/blob/master/f/tst-search2.c

Alternative test: Put “nameserver 255.255.255.255” as the first name server into /etc/resolv.conf, and run “getent ahosts does-not-exist”.  You need to have non-empty search path, too (“search redhat.com”, for example).

Comment 11 Michael Petlan 2016-08-04 10:15:39 EDT

Failed with glibc-2.17-105.el7 and passed with glibc-2.17-156.el7.

VERIFIED.

Comment 13 errata-xmlrpc 2016-11-03 04:31:14 EDT

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/RHSA-2016-2573.html

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