Bug 1077343 (CVE-2014-2523)

Summary:	CVE-2014-2523 kernel: netfilter: nf_conntrack_dccp: incorrect skb_header_pointer API usages
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, aquini, bhu, carnil, ctrianta, davej, dhoward, edbrand, esammons, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, jkurik, jonathan, jross, jscalf, jwboyer, kernel-maint, kernel-mgr, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mmilgram, npajkovs, pholasek, plougher, pmatouse, ppandit, rt-maint, rvrbovsk, shobbs, 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:	2014-06-03 07:15:20 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:	1077345, 1077346, 1077347, 1077349, 1077350, 1077351, 1083122, 1083123, 1083124
Bug Blocks:	1077357

Description Petr Matousek 2014-03-17 19:17:27 UTC

Description of the problem:

Some occurences in the netfilter tree use skb_header_pointer() in
the following way ...

  struct dccp_hdr _dh, *dh;
  ...
  skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);

... where dh itself is a pointer that is being passed as the copy
buffer. Instead, we need to use &_dh as the forth argument so that
we're copying the data into an actual buffer that sits on the stack.

A remote attacker could use this flaw to crash the system or,
potentially, escalate their privileges on the system.

References:
http://www.openwall.com/lists/oss-security/2014/03/17/3

Introduced by:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2bc780499aa3

Upstream fix:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b22f5126a24b

Comment 1 Petr Matousek 2014-03-17 19:21:43 UTC

Statement:

This issue does not affect the versions of the kernel package as shipped with
Red Hat Enterprise Linux 5.

Comment 4 Petr Matousek 2014-03-17 19:25:19 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1077350]

Comment 5 Fedora Update System 2014-03-28 03:16:02 UTC

kernel-3.13.7-200.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 6 Fedora Update System 2014-03-28 03:18:00 UTC

kernel-3.13.7-100.fc19 has been pushed to the Fedora 19 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 8 Ed Brand 2014-04-02 17:19:02 UTC

Question on alternatives:

Are there any workarounds/config changes that can be implemented to mitigate the risk such as the ones listeed in the followin link:

https://odesk.by/archives/2107#more-2107

My concern is with RHEL 6 where no patch exists yet.

Comment 9 Petr Matousek 2014-04-03 08:27:10 UTC

(In reply to Ed Brand from comment #8)
> Are there any workarounds/config changes that can be implemented to mitigate
> the risk such as the ones listeed in the followin link:
> 
> https://odesk.by/archives/2107#more-2107
> 
> My concern is with RHEL 6 where no patch exists yet.

The link pretty much sums up the mitigation options. I'd recommend to prevent nf_conntrack_proto_dccp module from being loaded by adding "install nf_conntrack_proto_dccp /bin/true" to file "/etc/modprobe.d/blacklist.conf".

Hope that helps.

--
Petr Matousek / Red Hat Security Response Team

Comment 12 errata-xmlrpc 2014-04-28 16:57:00 UTC

This issue has been addressed in following products:

  MRG for RHEL-6 v.2

Via RHSA-2014:0439 https://rhn.redhat.com/errata/RHSA-2014-0439.html

Comment 13 errata-xmlrpc 2014-05-07 18:48:13 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2014:0475 https://rhn.redhat.com/errata/RHSA-2014-0475.html

Comment 16 Vincent Danen 2014-05-21 11:47:55 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6.2 AUS

Via RHSA-2014:0520 https://rhn.redhat.com/errata/RHSA-2014-0520.html

Comment 17 errata-xmlrpc 2014-06-03 16:27:17 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6.3 EUS - Server and Compute Node Only

Via RHSA-2014:0593 https://rhn.redhat.com/errata/RHSA-2014-0593.html

Comment 18 errata-xmlrpc 2014-06-04 17:07:48 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6.4 EUS - Server and Compute Node Only

Via RHSA-2014:0634 https://rhn.redhat.com/errata/RHSA-2014-0634.html