Bug 917012 (CVE-2013-1796)

Summary:	CVE-2013-1796 kernel: kvm: buffer overflow in handling of MSR_KVM_SYSTEM_TIME
Product:	[Other] Security Response	Reporter:	Petr Matousek <pmatouse>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	agordeev, anton, areis, dhoward, dlaor, ehabkost, ekuric, fhrbata, gleb, jlieskov, knoel, lwang, minovotn, mkenneth, mtosatti, npajkovs, qzhang, rhod, security-response-team, sforsber
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:	2013-04-23 20:58:08 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:	917018, 917019, 917020, 917021, 923966, 964429, 964430
Bug Blocks:	917037

Description Petr Matousek 2013-03-01 13:18:07 UTC

Description of the problem:
If the guest sets the GPA of the time_page so that the request to update the 
time straddles a page then KVM will write onto an incorrect page.  The
write is done byusing kmap atomic to get a pointer to the page for the time
structure and then performing a memcpy to that page starting at an offset
that the guest controls.  Well behaved guests always provide a 32-byte aligned
address, however a malicious guest could use this to corrupt host kernel
memory.

Acknowledgements:

Red Hat would like to thank Andrew Honig of Google for reporting this issue.

Comment 1 Petr Matousek 2013-03-01 13:19:06 UTC

Statement:

This issue did not affect the versions of Linux kernel as shipped with Red Hat
Enterprise Linux 5 and Red Hat Enterprise MRG as they did not provide support
for the KVM subsystem.

Comment 5 Petr Matousek 2013-03-20 10:01:01 UTC

Upstream fix:

https://git.kernel.org/cgit/virt/kvm/kvm.git/commit/?id=c300aa64ddf57d9c5d9c898a64b36877345dd4a9

Comment 6 Petr Matousek 2013-03-20 19:46:25 UTC

Created kernel tracking bugs for this issue

Affects: fedora-all [bug 923966]

Comment 11 Fedora Update System 2013-03-23 23:58:15 UTC

kernel-3.8.4-202.fc18 has been pushed to the Fedora 18 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 16 errata-xmlrpc 2013-04-09 18:14:50 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2013:0727 https://rhn.redhat.com/errata/RHSA-2013-0727.html

Comment 17 errata-xmlrpc 2013-04-23 18:28:07 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2013:0744 https://rhn.redhat.com/errata/RHSA-2013-0744.html

Comment 18 errata-xmlrpc 2013-04-23 18:56:34 UTC

This issue has been addressed in following products:

  RHEV-H and Agents for RHEL-6

Via RHSA-2013:0746 https://rhn.redhat.com/errata/RHSA-2013-0746.html

Comment 20 errata-xmlrpc 2013-06-11 17:40:21 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6.3 EUS - Server Only

Via RHSA-2013:0928 https://rhn.redhat.com/errata/RHSA-2013-0928.html

Comment 21 errata-xmlrpc 2013-07-09 15:05:58 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 6.2 EUS - Server Only

Via RHSA-2013:1026 https://rhn.redhat.com/errata/RHSA-2013-1026.html