Bug 1302588 (CVE-2016-0746)

Summary:	CVE-2016-0746 nginx: use-after-free during CNAME response processing in resolver
Product:	[Other] Security Response	Reporter:	Martin Prpič <mprpic>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	affix, athmanem, bperkins, dkholia, jeremy, jkaluza, jorton, mmaslano, pavel.lisy, peter.borsa, webstack-team, wtogami
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	nginx 1.9.10, nginx 1.8.1	Doc Type:	Bug Fix
Doc Text:	A use-after-free flaw was found in the way nginx resolved certain CNAME DNS records. An attacker able to manipulate DNS responses received by nginx could use this flaw to cause a worker process to crash or, possibly, execute arbitrary code if nginx enabled the resolver in its configuration.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-07-14 11:21:20 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1302334, 1302337, 1302592, 1302599, 1342443
Bug Blocks:	1302591

Description Martin Prpič 2016-01-28 08:41:23 UTC

The following flaw was found in the nginx resolver:

Use-after-free condition might occur during CNAME response processing. This problem allows an attacker who is able to trigger name resolution to cause worker process crash, or might have potential other impact.

This issue affects nginx only if the "resolver" directive is used in a configuration file.

The problems are fixed in nginx upstream versions 1.9.10 and 1.8.1.

External References:

http://mailman.nginx.org/pipermail/nginx-announce/2016/000169.html

Comment 1 Martin Prpič 2016-01-28 08:45:07 UTC

Created nginx tracking bugs for this issue:

Affects: fedora-all [bug 1302592]

Comment 2 Tomas Hoger 2016-02-10 21:49:28 UTC

Bug 1302589 comment 3 as few notes on how nginx resolver is used.

Comment 3 Tomas Hoger 2016-02-10 21:50:42 UTC

These upstream commits seem relevant to this issue:

https://trac.nginx.org/nginx/changeset/f63dd04c158062d73fcb6aff59124910fa1fae75/nginx
https://trac.nginx.org/nginx/changeset/838946300825379ccdd3acfb131cf66d6ae3cb85/nginx
https://trac.nginx.org/nginx/changeset/5557bf31e25da68d5cda19dbc91d86f47430df1f/nginx
https://trac.nginx.org/nginx/changeset/dac6eda40475f08b7372159d78dad1e13cd5bc7f/nginx

Comment 6 errata-xmlrpc 2016-07-14 05:50:24 UTC

This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.1 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 6
  Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS

Via RHSA-2016:1425 https://access.redhat.com/errata/RHSA-2016:1425