Bug 1097746 (CVE-2012-6647)

Summary:	CVE-2012-6647 Kernel: futex: forbid uaddr == uaddr2 in futex_wait_requeue_pi()
Product:	[Other] Security Response	Reporter:	Prasad Pandit <ppandit>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	agordeev, aquini, bhu, carnil, davej, dhoward, esammons, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, jkurik, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, nobody, npajkovs, pholasek, plougher, pmatouse, rt-maint, rvrbovsk, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	A NULL pointer dereference flaw was found in the way the futex_wait_requeue_pi() function of the Linux kernel's futex subsystem handled the requeuing of certain Priority Inheritance (PI) futexes. A local, unprivileged user could use this flaw to crash the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2014-07-29 16:16:03 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:	1097759, 1097760
Bug Blocks:	1097133

Description Prasad Pandit 2014-05-14 12:48:01 UTC

Linux kernel built with the fast userspace mutexes(CONFIG_FUTEX) support is
vulnerable to a NULL pointer dereference flaw. It could occur when a waiting
task requests wait to be re-queued from non-PI futex to a PI-aware futex via
FUTEX_WAIT_REQUEUE_PI operation.

An unprivileged user/program could use this flaw to crash the system kernel
resulting in DoS.

Upstream fix:
-------------
  -> https://git.kernel.org/linus/6f7b0a2a5c0fb03be7c25bd1745baa50582348ef

Introduced in:
--------------
  -> https://git.kernel.org/linus/52400ba946759af28442dee6265c5c0180ac7122

Comment 1 Prasad Pandit 2014-05-14 13:16:53 UTC

Statement:

This issue does not affect the versions of the kernel package as shipped with
Red Hat Enterprise Linux 5 and 7, and Red Hat Enterprise MRG 2.

Comment 4 Martin Prpič 2014-07-29 11:20:57 UTC

IssueDescription:

A NULL pointer dereference flaw was found in the way the futex_wait_requeue_pi() function of the Linux kernel's futex subsystem handled the requeuing of certain Priority Inheritance (PI) futexes. A local, unprivileged user could use this flaw to crash the system.

Comment 5 errata-xmlrpc 2014-07-29 15:53:38 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2014:0981 https://rhn.redhat.com/errata/RHSA-2014-0981.html