Bug 755584 (CVE-2011-4326)

Summary:	CVE-2011-4326 kernel: wrong headroom check in udp6_ufo_fragment()
Product:	[Other] Security Response	Reporter:	Petr Matousek <pmatouse>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	agordeev, anton, arozansk, bhu, davej, dhoward, fhrbata, gansalmon, hui.zhu, itamar, jkacur, jonathan, jwboyer, kernel-maint, kernel-mgr, lgoncalv, lwang, madhu.chinakonda, plougher, rcvalle, rt-maint, sforsber, tcallawa, vgoyal, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2012-03-28 08:41:27 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:	698170, 753167, 755589, 755590, 761341
Bug Blocks:	755624

Description Petr Matousek 2011-11-21 14:36:26 UTC

A bug was found in the way headroom check was performed in udp6_ufo_fragment() function. A remote attacker could use this flaw to crash the system.

Upstream patch:
a9cf73ea7ff78f52662c8658d93c226effbbedde

Comment 1 Petr Matousek 2011-11-21 14:37:24 UTC

Details (copied from 682066#c0):

The kernel panic occurs if a bridge device is connected with physical NIC and
UDP packets are transmitted via the bridge device.

The kernel panic occurs when all the following conditions consist:
- The kernel version is RHEL6(2.6.32-71.xx.el6).
- The NETIF_F_HW_CSUM of the physical device connected with the bridge device
is available.
- The udp-fragmentation-offload function of the bridge device is available(ON).
- The udp-fragmentation-offload function of the physical NIC is
unavailable(OFF).
- IPv6 protocol
- The size of the UDP datagram exceeds MTU. (fragmentation is necessary)

Comment 3 Petr Matousek 2011-11-21 14:41:30 UTC

Created kernel tracking bugs for this issue

Affects: fedora-all [bug 755590]

Comment 5 Petr Matousek 2011-11-21 14:50:22 UTC

Statement:

This issue did not affect the versions of Linux kernel as shipped with Red Hat
Enterprise Linux 4 and 5 as they did not provide support for UDP Fragmentation Offload (UFO) functionality. This has been addressed in Red Hat Enterprise Linux 6 and Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2011-1465.html, and https://rhn.redhat.com/errata/RHSA-2012-0010.html.

Comment 6 errata-xmlrpc 2011-11-22 16:53:44 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2011:1465 https://rhn.redhat.com/errata/RHSA-2011-1465.html

Comment 7 Fedora Update System 2011-11-29 00:21:53 UTC

kernel-2.6.35.14-106.fc14 has been pushed to the Fedora 14 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 9 errata-xmlrpc 2012-01-10 20:17:12 UTC

This issue has been addressed in following products:

  MRG for RHEL-6 v.2

Via RHSA-2012:0010 https://rhn.redhat.com/errata/RHSA-2012-0010.html