Upstream information
Description
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service via degenerate chains of linear pagetables, because of an incorrect fix for CVE-2017-15595. "Linear pagetables" is a technique which involves either pointing a pagetable at itself, or to another pagetable of the same or higher level. Xen has limited support for linear pagetables: A page may either point to itself, or point to another pagetable of the same level (i.e., L2 to L2, L3 to L3, and so on). XSA-240 introduced an additional restriction that limited the "depth" of such chains by allowing pages to either *point to* other pages of the same level, or *be pointed to* by other pages of the same level, but not both. To implement this, we keep track of the number of outstanding times a page points to or is pointed to another page table, to prevent both from happening at the same time. Unfortunately, the original commit introducing this reset this count when resuming validation of a partially-validated pagetable, incorrectly dropping some "linear_pt_entry" counts. If an attacker could engineer such a situation to occur, they might be able to make loops or other arbitrary chains of linear pagetables, as described in XSA-240. A malicious or buggy PV guest may cause the hypervisor to crash, resulting in Denial of Service (DoS) affecting the entire host. Privilege escalation and information leaks cannot be excluded. All versions of Xen are vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can leverage the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Only systems which have enabled linear pagetables are vulnerable. Systems which have disabled linear pagetables, either by selecting CONFIG_PV_LINEAR_PT=n when building the hypervisor, or adding pv-linear-pt=false on the command-line, are not vulnerable.SUSE information
Overall state of this security issue: Resolved
This issue is currently rated as having important severity.
National Vulnerability Database | |
---|---|
Base Score | 7.2 |
Vector | AV:L/AC:L/Au:N/C:C/I:C/A:C |
Access Vector | Local |
Access Complexity | Low |
Authentication | None |
Confidentiality Impact | Complete |
Integrity Impact | Complete |
Availability Impact | Complete |
National Vulnerability Database | SUSE | |
---|---|---|
Base Score | 8.8 | 7.5 |
Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H |
Access Vector | Local | Local |
Access Complexity | Low | High |
Privileges Required | Low | High |
User Interaction | None | None |
Scope | Changed | Changed |
Confidentiality Impact | High | High |
Integrity Impact | High | High |
Availability Impact | High | High |
CVSSv3 Version | 3.1 | 3.1 |
- SUSE-SU-2019:3296-1, published Fri Dec 13 16:13:50 MST 2019
- SUSE-SU-2019:3297-1, published Fri Dec 13 16:10:48 MST 2019
- SUSE-SU-2019:3309-1, published Mon Dec 16 10:15:00 MST 2019
- SUSE-SU-2019:3310-1, published Mon Dec 16 10:13:14 MST 2019
- SUSE-SU-2019:3338-1, published Wed Dec 18 16:12:00 MST 2019
- SUSE-SU-2020:0334-1, published Thu Feb 6 07:14:05 MST 2020
- SUSE-SU-2020:0388-1, published Mon Feb 17 10:11:14 MST 2020
- SUSE-SU-2020:14444-1, published Tue Aug 4 13:39:14 MDT 2020
- SUSE-SU-2020:1630-1, published Tue Jun 16 13:12:19 MDT 2020
List of released packages
Product(s) | Fixed package version(s) | References |
---|---|---|
HPE Helion Openstack 8 |
| Patchnames: HPE-Helion-OpenStack-8-2019-3297 HPE-Helion-OpenStack-8-2020-1630 |
Image SLES15-EC2-CHOST-HVM-BYOS |
| |
Image SLES15-SP1-CHOST-BYOS-EC2 |
| |
SUSE CaaS Platform 3.0 |
| Patchnames: SUSE-CAASP-3.0-2019-3297 |
SUSE Enterprise Storage 5 |
| Patchnames: SUSE-Storage-5-2019-3297 SUSE-Storage-5-2020-1630 |
SUSE Linux Enterprise Desktop 12 SP4 |
| Patchnames: SUSE-SLE-DESKTOP-12-SP4-2019-3310 |
SUSE Linux Enterprise Module for Basesystem 15 SP1 |
| Patchnames: SUSE-SLE-Module-Basesystem-15-SP1-2019-3338 |
SUSE Linux Enterprise Module for Basesystem 15 |
| Patchnames: SUSE-SLE-Module-Basesystem-15-2019-3309 |
SUSE Linux Enterprise Module for Open Buildservice Development Tools 15 SP1 |
| Patchnames: SUSE-SLE-Module-Development-Tools-OBS-15-SP1-2019-3338 |
SUSE Linux Enterprise Module for Server Applications 15 SP1 |
| Patchnames: SUSE-SLE-Module-Server-Applications-15-SP1-2019-3338 |
SUSE Linux Enterprise Module for Server Applications 15 |
| Patchnames: SUSE-SLE-Module-Server-Applications-15-2019-3309 |
SUSE Linux Enterprise Point of Sale 12 SP2-CLIENT |
| Patchnames: SUSE-SLE-POS-12-SP2-CLIENT-2020-334 |
SUSE Linux Enterprise Server 11 SP4-LTSS SUSE Linux Enterprise Server for SAP Applications 11 SP4-LTSS |
| Patchnames: slessp4-xen-14444 |
SUSE Linux Enterprise Server 12 SP1-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP1-LTSS |
| Patchnames: SUSE-SLE-SERVER-12-SP1-2020-388 |
SUSE Linux Enterprise Server 12 SP2-BCL SUSE Linux Enterprise Server for SAP Applications 12 SP2-BCL |
| Patchnames: SUSE-SLE-SERVER-12-SP2-BCL-2020-334 |
SUSE Linux Enterprise Server 12 SP2-ESPOS SUSE Linux Enterprise Server for SAP Applications 12 SP2-ESPOS |
| Patchnames: SUSE-SLE-SERVER-12-SP2-ESPOS-2020-334 |
SUSE Linux Enterprise Server 12 SP2-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP2-LTSS |
| Patchnames: SUSE-SLE-SERVER-12-SP2-2020-334 |
SUSE Linux Enterprise Server 12 SP3-BCL SUSE Linux Enterprise Server for SAP Applications 12 SP3-BCL |
| Patchnames: SUSE-SLE-SERVER-12-SP3-BCL-2019-3297 SUSE-SLE-SERVER-12-SP3-BCL-2020-1630 |
SUSE Linux Enterprise Server 12 SP3-ESPOS SUSE Linux Enterprise Server for SAP Applications 12 SP3-ESPOS |
| Patchnames: SUSE-SLE-SERVER-12-SP3-ESPOS-2019-3297 SUSE-SLE-SERVER-12-SP3-ESPOS-2020-1630 |
SUSE Linux Enterprise Server 12 SP3-LTSS SUSE Linux Enterprise Server for SAP Applications 12 SP3-LTSS |
| Patchnames: SUSE-SLE-SERVER-12-SP3-2019-3297 SUSE-SLE-SERVER-12-SP3-2020-1630 |
SUSE Linux Enterprise Server 12 SP4 SUSE Linux Enterprise Server for SAP Applications 12 SP4 |
| Patchnames: SUSE-SLE-SERVER-12-SP4-2019-3310 |
SUSE Linux Enterprise Server 12 SP5 SUSE Linux Enterprise Server for SAP Applications 12 SP5 |
| Patchnames: SUSE-SLE-SERVER-12-SP5-2019-3296 |
SUSE Linux Enterprise Server for SAP Applications 12 SP1 |
| Patchnames: SUSE-SLE-SAP-12-SP1-2020-388 |
SUSE Linux Enterprise Server for SAP Applications 12 SP2 |
| Patchnames: SUSE-SLE-SAP-12-SP2-2020-334 |
SUSE Linux Enterprise Server for SAP Applications 12 SP3 |
| Patchnames: SUSE-SLE-SAP-12-SP3-2019-3297 SUSE-SLE-SAP-12-SP3-2020-1630 |
SUSE Linux Enterprise Software Development Kit 12 SP4 |
| Patchnames: SUSE-SLE-SDK-12-SP4-2019-3310 |
SUSE Linux Enterprise Software Development Kit 12 SP5 |
| Patchnames: SUSE-SLE-SDK-12-SP5-2019-3296 |
SUSE OpenStack Cloud 7 |
| Patchnames: SUSE-OpenStack-Cloud-7-2020-334 |
SUSE OpenStack Cloud 8 |
| Patchnames: SUSE-OpenStack-Cloud-8-2019-3297 SUSE-OpenStack-Cloud-8-2020-1630 |
SUSE OpenStack Cloud Crowbar 8 |
| Patchnames: SUSE-OpenStack-Cloud-Crowbar-8-2019-3297 SUSE-OpenStack-Cloud-Crowbar-8-2020-1630 |
openSUSE Leap 15.1 |
| Patchnames: openSUSE-2020-11 |
Status of this issue by product and package
Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification.
Product(s) | Source package | State |
---|---|---|
SUSE CaaS Platform 3.0 | xen | Released |
SUSE Container as a Service Platform 1.0 | xen | Unsupported |
SUSE Container as a Service Platform 2.0 | xen | Unsupported |
SUSE Linux Enterprise 15 Module for Basesystem | xen | Released |
SUSE Linux Enterprise 15 Module for Server Applications | xen | Released |
SUSE Linux Enterprise 15-SP1 Module for Basesystem | xen | Released |
SUSE Linux Enterprise 15-SP1 Module for Server Applications | xen | Released |
SUSE Linux Enterprise Desktop 12 SP4 | xen | Released |
SUSE Linux Enterprise High Performance Computing 12 SP4 | xen | Released |
SUSE Linux Enterprise High Performance Computing 12 SP5 | xen | Released |
SUSE Linux Enterprise Server 11 SP4 LTSS | xen | Released |
SUSE Linux Enterprise Server 12 SP1 LTSS | xen | Released |
SUSE Linux Enterprise Server 12 SP2 LTSS | xen | Released |
SUSE Linux Enterprise Server 12 SP3 BCL | xen | Released |
SUSE Linux Enterprise Server 12 SP3 LTSS | xen | Released |
SUSE Linux Enterprise Server 12 SP4 | xen | Released |
SUSE Linux Enterprise Server 12 SP5 | xen | Released |
SUSE Linux Enterprise Server for SAP Applications 12 SP2 | xen | Released |
SUSE Linux Enterprise Server for SAP Applications 12 SP3 | xen | Released |
SUSE Linux Enterprise Server for SAP Applications 12 SP4 | xen | Released |
SUSE Linux Enterprise Server for SAP Applications 12 SP5 | xen | Released |
SUSE Linux Enterprise Software Development Kit 12 SP4 | xen | Released |
SUSE Linux Enterprise Software Development Kit 12 SP5 | xen | Released |