| Summary: | <app-emulation/xen-{4.2.5-r3,4.3.3-r3,4.4.1-r4}: p2m lock starvation (CVE-2014-{9065,9066}) | ||
|---|---|---|---|
| Product: | Gentoo Security | Reporter: | Agostino Sarubbo <ago> |
| Component: | Vulnerabilities | Assignee: | Gentoo Security <security> |
| Status: | RESOLVED FIXED | ||
| Severity: | minor | CC: | xen |
| Priority: | Normal | ||
| Version: | unspecified | ||
| Hardware: | All | ||
| OS: | Linux | ||
| URL: | http://www.openwall.com/lists/oss-security/2014/12/08/4 | ||
| Whiteboard: | B3 [glsa] | ||
| Package list: | Runtime testing required: | --- | |
fixed in xen-4.2.5-r3, xen-4.3.3-r3, xen-4.4.1-r4 Arches, please test and mark stable: =app-emulation/xen-4.2.5-r3 Target keywords Both : "amd64 x86" =app-emulation/xen-4.3.3-r3 Target keywords Only: "amd64" amd64 stable x86 stable. Maintainer(s), please cleanup. Security, please vote. CVE-2014-9066 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-9066): Xen 4.4.x and earlier, when using a large number of VCPUs, does not properly handle read and write locks, which allows local x86 guest users to cause a denial of service (write denial or NMI watchdog timeout and host crash) via a large number of read request, a different vulnerability than CVE-2014-9065. CVE-2014-9065 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-9065): common/spinlock.c in Xen 4.4.x and earlier does not properly handle read and write locks, which allows local x86 guest users to cause a denial of service (write denial or NMI watchdog timeout and host crash) via a large number of read requests, a different vulnerability to CVE-2014-9066. (In reply to GLSAMaker/CVETool Bot from comment #4) > CVE-2014-9066 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-9066): > Xen 4.4.x and earlier, when using a large number of VCPUs, does not > > CVE-2014-9065 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-9065): > common/spinlock.c in Xen 4.4.x and earlier does not properly handle read this two bugs already fixed at versions =app-emulation/xen-4.2.5-r3 =app-emulation/xen-4.3.3-r3 which already goes stable. Maintainer(s), Thank you for you for cleanup. Added to an existing GLSA Request. This issue was resolved and addressed in GLSA 201504-04 at https://security.gentoo.org/glsa/201504-04 by GLSA coordinator Yury German (BlueKnight). |
From ${URL} : Xen Security Advisory CVE-2014-9065,CVE-2014-9066 / XSA-114 version 3 p2m lock starvation UPDATES IN VERSION 3 ==================== Public release. ISSUE DESCRIPTION ================= The current read/write lock implementation is read-biased, which allows a consistent stream of readers to starve writers indefinitely. There are certain rwlocks where guests are capable of applying arbitrary read pressure. IMPACT ====== A malicious guest administrator can deny service to other tasks. If the NMI watchdog is active, a timeout might be triggered, resulting in a host crash. VULNERABLE SYSTEMS ================== Xen 4.2 and later systems are vulnerable. Xen 4.1 and earlier are not vulnerable in normal configurations. 4.1 and earlier are vulnerable only insofar as features are used which have already been explicitly discounted for security support purposes (TMEM, see XSA-15; XSM-based radical disaggregation, see XSA-77). Only x86 systems offer avenues for attacking this vulnerability. ARM systems do not and are therefore not vulnerable. MITIGATION ========== There is no mitigation available for this issue. CREDITS ======= This issue was discovered by Andrew Cooper of Citrix. RESOLUTION ========== Applying the appropriate attached patch resolves this issue in practice for most systems. (CVE-2014-9065 refers to these fixed cases.) In some deployments, large guests (more than around 30-40 VCPUs) may still be able to trigger intermittent problems; a complete fix to this issue requires substantial structural changes and is planned for Xen 4.6. (CVE-2014-9066 refers to these yet-to-be-fixed cases.) @maintainer(s): after the bump, in case we need to stabilize the package, please let us know if it is ready for the stabilization or not.