Bug 1343072 (CVE-2015-8899)

Summary:	CVE-2015-8899 dnsmasq: Denial-of-service when empty address from DNS overlays A record from hosts
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	abaron, aortega, apevec, ayoung, chrisw, dmoppert, itamar, jrusnack, jschluet, laine, lhh, lpeer, markmc, psimerda, rbryant, sclewis, slong, srevivo, tdecacqu, thozza, veillard
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A NULL pointer dereference flaw was found in dmsmasq in the cache_insert() function. An attacker could exploit this flaw by locally defining an A or AAAA record in the /etc/hosts file that is not in the upstream server. When the upstream server sends a reply that the same name is empty, dmsmasq crashes (denial of service).	Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-06-11 02:28:11 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:	1343073
Bug Blocks:	1343074

Description Andrej Nemec 2016-06-06 12:52:48 UTC

A vulnerability was found in dmsmasq. A Denial-of-service will occur when an A or AAAA record is defined locally, in a hosts file, and an upstream server sends a reply that the same name is empty.

Upstream bug:

http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2016q2/010479.html

Upstream fix:

http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=41a8d9e99be9f2cc8b02051dd322cb45e0faac87

Comment 1 Andrej Nemec 2016-06-06 12:53:45 UTC

Created dnsmasq tracking bugs for this issue:

Affects: fedora-all [bug 1343073]

Comment 2 Doran Moppert 2016-06-07 01:40:21 UTC

Low impact as the worst this can cause is a denial of service.

Vulnerable code was introduced in v2.73:  all RHEL versions ship earlier
versions of dnsmasq which are not affected by this issue.

Comment 3 Summer Long 2016-06-09 23:43:19 UTC

Created attachment 1166437 [details]
Patch for version2.75

http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=patch;h=41a8d9e99be9f2cc8b02051dd322cb45e0faac87

Comment 4 Summer Long 2016-06-10 00:17:54 UTC

Same as RHEL (see comment #2). All RHOSP versions ship earlier dnsmasq versions (either 2.48 or 2.66), and are not affected by this issue.