Bug 1218454 (CVE-2015-6526)

Summary:	CVE-2015-6526 kernel: perf on ppc64 can loop forever getting userlevel stacktraces
Product:	[Other] Security Response	Reporter:	Fabio Olive Leite <fleite>
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, arm-mgr, bhu, carnil, dhoward, esammons, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, nmurray, plougher, pmatouse, rt-maint, rvrbovsk, slong, vgoyal, williams, wmealing
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	A flaw was found in the way the Linux kernel's perf subsystem retrieved userlevel stack traces on PowerPC systems. A local, unprivileged user could use this flaw to cause a denial of service on the system by creating a special stack layout that would force the perf_callchain_user_64() function into an infinite loop.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-08-10 05:54:09 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:	1213950, 1253892
Bug Blocks:	1218457

Description Fabio Olive Leite 2015-05-05 00:29:25 UTC

A malicious user could create a special stack layout that fools
the perf_callchain_user_64 function into an infinite loop, tying up
that particular CPU and the process can not be killed.

A kernel patch was committed upstream capping the maximum userlevel
stacktrace collected by perf to PERF_MAX_STACK_DEPTH on 64bit powerpc
architectures. This affects all ppc64 kernels that support perf.

This seems to be kind of local DOS that can be resolved when the system is
rebooted.

References:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9a5cbce421a283e6aea3c4007f141735bf9da8c3

CVE assignment:
http://seclists.org/oss-sec/2015/q3/410

Comment 2 Wade Mealing 2015-08-15 04:46:21 UTC

Statement:

This issue does not affect the Linux kernels as shipped with Red Hat Enterprise Linux 5, 6 and Red Hat Enterprise MRG 2.

This issue affects the Linux kernels as shipped with Red Hat Enterprise Linux 7  and may be addressed in a future update.

Comment 3 Wade Mealing 2015-08-15 06:08:16 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1253892]

Comment 4 Adam Mariš 2015-08-21 13:40:47 UTC

CVE assignment:

http://seclists.org/oss-sec/2015/q3/410

Comment 6 errata-xmlrpc 2015-11-19 22:14:47 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2015:2152 https://rhn.redhat.com/errata/RHSA-2015-2152.html

Comment 7 errata-xmlrpc 2015-11-19 23:25:49 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2015:2152 https://rhn.redhat.com/errata/RHSA-2015-2152.html