Bug 756084 (CVE-2011-4347) - CVE-2011-4347 kernel: kvm: device assignment DoS
Summary: CVE-2011-4347 kernel: kvm: device assignment DoS
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2011-4347
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 756092 756093 770094 770095 770096 770097 770098 771678 816630
Blocks: 755387
TreeView+ depends on / blocked
 
Reported: 2011-11-22 16:41 UTC by Petr Matousek
Modified: 2019-09-29 12:48 UTC (History)
20 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-09-18 11:58:16 UTC


Attachments (Terms of Use)


Links
System ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2012:0149 normal SHIPPED_LIVE Moderate: kvm security and bug fix update 2012-02-21 07:24:43 UTC
Red Hat Product Errata RHSA-2012:0350 normal SHIPPED_LIVE Moderate: kernel security and bug fix update 2012-03-06 23:43:05 UTC
Red Hat Product Errata RHSA-2012:1042 normal SHIPPED_LIVE Important: kernel security and bug fix update 2012-06-26 22:40:37 UTC

Description Petr Matousek 2011-11-22 16:41:57 UTC
It was found that kvm_vm_ioctl_assign_device function did not check if the user requesting assignment was privileged or not. Together with /dev/kvm being 666, unprivileged user could assign unused pci devices, or even devices that were in use and whose resources were not properly claimed by the respective drivers.

Please note that privileged access was still needed to re-program the device to for example issue DMA requests. This is typically achieved by touching files on sysfs filesystem. These files are usually not accessible to unprivileged users.

As a result, local user could use this flaw to crash the system.

Reference:
http://thread.gmane.org/gmane.comp.emulators.kvm.devel/82043

Acknowledgements:

Red Hat would like to thank Sasha Levin for reporting this issue.

Comment 6 Petr Matousek 2011-12-23 11:05:58 UTC
Created kernel tracking bugs for this issue

Affects: fedora-all [bug 770096]

Comment 7 Petr Matousek 2012-01-18 21:03:36 UTC
Statement:

This issue did not affect the versions of Linux kernel as shipped with Red Hat Enterprise Linux 4 and Red Hat Enterprise MRG as they did not provide support for the KVM subsystem. This has been addressed in Red Hat Enterprise Linux 6 via https://rhn.redhat.com/errata/RHSA-2012-0350.html. A future kvm update in Red Hat Enterprise 5 may address this flaw.

Comment 8 errata-xmlrpc 2012-02-21 03:15:26 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2012:0149 https://rhn.redhat.com/errata/RHSA-2012-0149.html

Comment 10 errata-xmlrpc 2012-03-06 18:45:00 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2012:0350 https://rhn.redhat.com/errata/RHSA-2012-0350.html

Comment 12 errata-xmlrpc 2012-06-26 18:41:28 UTC
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6.1 EUS - Server Only

Via RHSA-2012:1042 https://rhn.redhat.com/errata/RHSA-2012-1042.html


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