Allele Security Alert
ASA-2019-00160
Identifier(s)
ASA-2019-00160
Title
GDT and IDT limits were improperly restored during VMM context switches
Vendor(s)
The OpenBSD Project
Product(s)
OpenBSD
Affected version(s)
OpenBSD 6.4 before errata 016
OpenBSD 6.3 before errata 032
Fixed version(s)
OpenBSD 6.4 errata 016
OpenBSD 6.3 errata 032
Proof of concept
Unknown
Description
GDT and IDT limits were improperly restored during VMM context switches.
Technical details
Unknown
Credits
Maxime Villard (NetBSD)
Reference(s)
OpenBSD 6.4 Errata
https://www.openbsd.org/errata64.html
OpenBSD 6.3 Errata
https://www.openbsd.org/errata63.html
016_vmmints.patch.sig
https://ftp.openbsd.org/pub/OpenBSD/patches/6.4/common/016_vmmints.patch.sig
032_vmmints.patch.sig
https://ftp.openbsd.org/pub/OpenBSD/patches/6.3/common/032_vmmints.patch.sig
vmm(4): On VMX, use sgdt/sidt to reset the GDT/IDT limits after exiting
https://github.com/openbsd/src/commit/5845e8e5e66cca51f6bca3dece4e7edb77b067fd#diff-7c576d5acc552c677e9172711c27cabb
If there is any error in this alert or you wish a comprehensive analysis, let us know.
Last modified: March 28, 2019