CVE-2023-46841

Publication date 20 March 2024

Last updated 24 July 2024


Ubuntu priority

Recent x86 CPUs offer functionality named Control-flow Enforcement Technology (CET). A sub-feature of this are Shadow Stacks (CET-SS). CET-SS is a hardware feature designed to protect against Return Oriented Programming attacks. When enabled, traditional stacks holding both data and return addresses are accompanied by so called “shadow stacks”, holding little more than return addresses. Shadow stacks aren’t writable by normal instructions, and upon function returns their contents are used to check for possible manipulation of a return address coming from the traditional stack. In particular certain memory accesses need intercepting by Xen. In various cases the necessary emulation involves kind of replaying of the instruction. Such replaying typically involves filling and then invoking of a stub. Such a replayed instruction may raise an exceptions, which is expected and dealt with accordingly. Unfortunately the interaction of both of the above wasn’t right: Recovery involves removal of a call frame from the (traditional) stack. The counterpart of this operation for the shadow stack was missing.

Read the notes from the security team

Status

Package Ubuntu Release Status
xen 24.10 oracular
Needs evaluation
24.04 LTS noble
Needs evaluation
23.10 mantic Ignored end of life, was needs-triage
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty Ignored end of standard support

Notes


mdeslaur

hypervisor packages are in universe. For issues in the hypervisor, add appropriate tags to each section, ex: Tags_xen: universe-binary