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: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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: impact=moderate,public=20130605,reported=20130605,source=oss-security,cvss2=3.8/AV:A/AC:M/Au:S/C:N/I:P/A:P,rhel-5/kernel-xen=notaffected,fedora-all/kernel=affected,rhel-6/kernel=notaffected,mrg-2/realtime-kernel=notaffected
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2013-06-05 15:47:00 EDT Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On: 971148    
Bug Blocks: 971153    

Description Petr Matousek 2013-06-05 15:44:23 EDT
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 15:47:00 EDT
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 15:47:59 EDT
Created kernel tracking bugs for this issue

Affects: fedora-all [bug 971148]