Bug 1163744 (CVE-2014-7843)

Summary:	CVE-2014-7843 kernel: aarch64: copying from /dev/zero causes local DoS
Product:	[Other] Security Response	Reporter:	Petr Matousek <pmatouse>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	agordeev, aquini, bhu, davej, dhoward, esammons, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, jonathan, jross, jrusnack, jwboyer, kernel-maint, kernel-mgr, kmcmartin, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, nmurray, pholasek, plougher, rt-maint, rvrbovsk, 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:	2014-11-13 12:02:02 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:	1161020, 1163745
Bug Blocks:	1163133

Description Petr Matousek 2014-11-13 12:00:25 UTC

It was found that a read of n*PAGE_SIZE+1 from /dev/zero
will cause the kernel to panic due to an unhandled exception since it's
not handling the single byte case with a fixup (anything larger than a
single byte will properly fault.)

A local, unprivileged user could use this flaw to crash the system.

Upstream patch proposal:

https://lkml.org/lkml/2014/11/12/584

Acknowledgements:

This issue was discovered by Miloš Prchlík of Red Hat.

Comment 1 Petr Matousek 2014-11-13 12:02:02 UTC

Statement CVE-2014-7825:

Not vulnerable.

This issue does not affect the Linux kernel packages as shipped with Red Hat
Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2.

Comment 2 Petr Matousek 2014-11-13 12:02:36 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1163745]

Comment 3 Fedora Update System 2014-11-18 12:17:35 UTC

kernel-3.17.3-300.fc21 has been pushed to the Fedora 21 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 4 Fedora Update System 2014-11-20 23:04:02 UTC

kernel-3.17.3-200.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.