Bug 1335803 (CVE-2016-4805)

Summary:	CVE-2016-4805 kernel: Use after free vulnerability in ppp_unregister_channel
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	agordeev, aquini, arm-mgr, bhu, blc, dhoward, esammons, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, kstutsma, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, mlangsdo, nmurray, pholasek, plougher, rt-maint, rvrbovsk, slawomir, sparks, vgoyal, williams, wmealing
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:	A use after free vulnerability was found in ppp_unregister_channel function. This is triggered when network namespace is removed while ppp_async channel is still registered in it and ppp_unregister_channel() tries to access its per-netns data in the defunct namespace. An attacker controlling this data could potentially denial of service the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-05-18 03:24:15 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:	1335804, 1335805
Bug Blocks:

Description Adam Mariš 2016-05-13 09:08:05 UTC

A use after free vulnerability was found in ppp_unregister_channel function. This is triggered when network namespace is removed while ppp_async channel is still registered in it and ppp_unregister_channel() tries to access its per-netns data in the defunct namespace.

An attacker who could control this memory that is being used in the defunct namespace could create a denial of service by spinlocking a CPU.

An unprivileged local user  could use this flaw to induce kernel memory corruption on the system, leading to a crash. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is unlikely.

Upstream patch:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=1f461dcdd296eecedaffffc6bae2bfa90bd7eb89

CVE request:

http://seclists.org/oss-sec/2016/q2/319

Comment 1 Adam Mariš 2016-05-13 09:08:56 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1335804]

Comment 2 Andrej Nemec 2016-05-16 07:13:01 UTC

CVE assignment:

http://seclists.org/oss-sec/2016/q2/346

Introduced by:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=273ec51dd7ceaa76e038875d85061ec856d8905e

Comment 3 Wade Mealing 2016-05-18 01:32:02 UTC

Statement:

This issue affects the Linux kernels as shipped with Red Hat Enterprise Linux 6, 7 realtime and MRG-2 kernels and does not plan to be addressed in a future update