| Name | CVE-2023-46842 |
| Description | Unlike 32-bit PV guests, HVM guests may switch freely between 64-bit and other modes. This in particular means that they may set registers used to pass 32-bit-mode hypercall arguments to values outside of the range 32-bit code would be able to set them to. When processing of hypercalls takes a considerable amount of time, the hypervisor may choose to invoke a hypercall continuation. Doing so involves putting (perhaps updated) hypercall arguments in respective registers. For guests not running in 64-bit mode this further involves a certain amount of translation of the values. Unfortunately internal sanity checking of these translated values assumes high halves of registers to always be clear when invoking a hypercall. When this is found not to be the case, it triggers a consistency check in the hypervisor and causes a crash. |
| Source | CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| xen (PTS) | bullseye | 4.14.6-1 | vulnerable |
| bullseye (security) | 4.14.5+94-ge49571868d-1 | vulnerable |
| bookworm | 4.17.3+10-g091466ba55-1~deb12u1 | vulnerable |
| sid, trixie | 4.17.3+36-g54dacb5c02-1 | vulnerable |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| xen | source | buster | (not affected) | | | |
| xen | source | bullseye | (unfixed) | end-of-life | | |
| xen | source | (unstable) | (unfixed) | | | |
Notes
[bookworm] - xen <postponed> (Minor issue, fix along in next DSA)
[bullseye] - xen <end-of-life> (EOLed in Bullseye)
[buster] - xen <not-affected> (Vulnerable code not present)
https://xenbits.xen.org/xsa/advisory-454.html