Description
Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared, this similar issue was not noticed.
References
http://www.openwall.com/lists/oss-security/2021/09/08/2
http://xenbits.xen.org/xsa/advisory-384.html
https://security.gentoo.org/glsa/202208-23
https://www.debian.org/security/2021/dsa-4977
https://xenbits.xenproject.org/xsa/advisory-384.txt
CVSS impact metrics
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
7.8 · High
CVSS V3.1
CVSS V3.0
CVSS V2.0
Information
Source identifier
Vulnerability status
Modified
Published
2021-09-08T14:15:08.547
3 years agoLast modified
2023-11-07T03:32:19.887
1 year ago