CVE-2020-11743 Information

Description

An issue was discovered in Xen through 4.13.x allowing guest OS users to cause a denial of service because of a bad error path in GNTTABOP_map_grant. Grant table operations are expected to return 0 for success and a negative number for errors. Some misplaced brackets cause one error path to return 1 instead of a negative value. The grant table code in Linux treats this condition as success and proceeds with incorrectly initialised state. A buggy or malicious guest can construct its grant table in such a way that when a backend domain tries to map a grant it hits the incorrect error path. This will crash a Linux based dom0 or backend domain.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00006.html http://www.openwall.com/lists/oss-security/2020/04/14/3 http://xenbits.xen.org/xsa/advisory-316.html https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5M2XRNCHOGGTJQBZQJ7DCV6ZNAKN3LE2/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NVTP4OYHCTRU3ONFJOFJQVNDFB25KLLG/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/YMAW7D2MP6RE4BFI5BZWOBBWGY3VSOFN/ https://security.gentoo.org/glsa/202005-08 https://www.debian.org/security/2020/dsa-4723 https://xenbits.xen.org/xsa/advisory-316.html

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5