Date: Thu, 05 Mar 2015 12:19:04 +0000 From: Xen.org security team <security@....org> To: xen-announce@...ts.xen.org, xen-devel@...ts.xen.org, xen-users@...ts.xen.org, oss-security@...ts.openwall.com CC: Xen.org security team <security@....org> Subject: Xen Security Advisory 121 (CVE-2015-2044) - Information leak via internal x86 system device emulation -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Xen Security Advisory CVE-2015-2044 / XSA-121 version 3 Information leak via internal x86 system device emulation UPDATES IN VERSION 3 ==================== Public release. ISSUE DESCRIPTION ================= Emulation routines in the hypervisor dealing with certain system devices check whether the access size by the guest is a supported one. When the access size is unsupported these routines failed to set the data to be returned to the guest for read accesses, so that hypervisor stack contents are copied into the destination of the operation, thus becoming visible to the guest. IMPACT ====== A malicious HVM guest might be able to read sensitive data relating to other guests. VULNERABLE SYSTEMS ================== Xen 3.2.x and later are vulnerable. Xen 3.1.x and earlier have not been inspected. Only HVM guests can take advantage of this vulnerability. Only x86 systems are vulnerable. ARM systems are not vulnerable. MITIGATION ========== Running only PV guests will avoid this issue. CREDITS ======= This issue was discovered by Jan Beulich of SUSE. RESOLUTION ========== Applying the attached patch resolves this issue. xsa121.patch xen-unstable, Xen 4.5.x, Xen 4.4.x, Xen 4.3.x, Xen 4.2.x $ sha256sum xsa121*.patch e74afb34e8059e8ee25b803019c192aa47c29208af2c19fb81aa84b0d7c0d268 xsa121.patch $ DEPLOYMENT DURING EMBARGO ========================= Deployment of the patches and/or mitigations described above (or others which are substantially similar) is permitted during the embargo, even on public-facing systems with untrusted guest users and administrators. Predisclosure list members who wish to deploy significantly different patches and/or mitigations, please contact the Xen Project Security Team. (Note: this during-embargo deployment notice is retained in post-embargo publicly released Xen Project advisories, even though it is then no longer applicable. This is to enable the community to have oversight of the Xen Project Security Team's decisionmaking.) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQEcBAEBAgAGBQJU+EmOAAoJEIP+FMlX6CvZnU0IAJZE8lD0dqlM9RyIMopSOZwp CYEVhmk03UsTIpJci1zVg+QUs7owe/p6tamuy4B/XFG6tGs4vsqVeUk8lvs8/Gzs 6RsEkHvOdy1Np9r8vCp2SShKsom0dE13t3JwAY+mftJNHFN2QTPmHbfi8XpnVotm 1nsLXl+8FAWa+d3ZULQTZXKJw6f2dNuXu9NHIvaNzP+IffJ6zKLPr9b8Va71yztA 0MPuUziRxVoJ5xWtoceN4qEdsnIZo5N9JN90fZSGSdiR976Qh1lhMu1ak4aVcNJa qljKSQQPOmfyHjyKsULvLlCYUldonkIfBVaJ+5QmZEVPMCDxig36m49QMOCNwOg= =BATt -----END PGP SIGNATURE----- [ CONTENT OF TYPE application/octet-stream SKIPPED ]
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