Bug 971146 (CVE-2013-2140)

Summary:	CVE-2013-2140 kernel: xen: blkback: insufficient permission checks for BLKIF_OP_DISCARD
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, anton, bhu, davej, dhoward, drjones, esammons, fhrbata, gansalmon, iboverma, imammedo, itamar, jforbes, jkacur, jonathan, jwboyer, kernel-maint, kernel-mgr, lersek, lgoncalv, lwang, madhu.chinakonda, matt, mcressma, mrezanin, npajkovs, pbonzini, plougher, rt-maint, rvrbovsk, williams, xen-maint
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:	2013-06-05 19:47:00 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:	971148
Bug Blocks:	971153

Description Petr Matousek 2013-06-05 19:44:23 UTC

If a system admin provides a disk (which supports the discard aka TRIM or SCSI UNMAP) to a guest as read-only - there are no checks done. 

A privileged guest user could use this flaw to destroy data on the disk to which he otherwise wouldn't have write access to.

References:

http://seclists.org/oss-sec/2013/q2/488

Comment 1 Petr Matousek 2013-06-05 19:47:00 UTC

Statement:

Not vulnerable.

This issue did not affect the versions of the kernel-xen package as shipped with Red Hat Enterprise Linux 5 as it has no support for BLKIF_OP_DISCARD.

This issue did not affect Red Hat Enterprise Linux 6 and Red Hat Enterprise MRG 2.

Comment 2 Petr Matousek 2013-06-05 19:47:59 UTC

Created kernel tracking bugs for this issue

Affects: fedora-all [bug 971148]

Comment 3 Kurt Seifried 2013-10-04 16:10:17 UTC

For future reference:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=604c499cbbcc3d5fe5fb8d53306aa0fae1990109
https://github.com/torvalds/linux/commit/604c499cbbcc3d5fe5fb8d53306aa0fae1990109