CVE-2022-42332

NameCVE-2022-42332
Descriptionx86 shadow plus log-dirty mode use-after-free In environments where host assisted address translation is necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode. Shadow mode maintains a pool of memory used for both shadow page tables as well as auxiliary data structures. To migrate or snapshot guests, Xen additionally runs them in so called log-dirty mode. The data structures needed by the log-dirty tracking are part of aformentioned auxiliary data. In order to keep error handling efforts within reasonable bounds, for operations which may require memory allocations shadow mode logic ensures up front that enough memory is available for the worst case requirements. Unfortunately, while page table memory is properly accounted for on the code path requiring the potential establishing of new shadows, demands by the log-dirty infrastructure were not taken into consideration. As a result, just established shadow page tables could be freed again immediately, while other code is still accessing them on the assumption that they would remain allocated.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-5378-1
Debian Bugs1033297

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
xen (PTS)jessie, jessie (lts)4.4.4lts5-0+deb8u1vulnerable
stretch (security), stretch (lts), stretch4.8.5.final+shim4.10.4-1+deb9u12vulnerable
buster (security), buster, buster (lts)4.11.4+107-gef32c7afa2-1vulnerable
bullseye4.14.6-1fixed
bullseye (security)4.14.5+94-ge49571868d-1fixed
bookworm4.17.3+10-g091466ba55-1~deb12u1fixed
sid, trixie4.17.3+36-g54dacb5c02-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
xensourcejessie(unfixed)end-of-life
xensourcestretch(unfixed)end-of-life
xensourcebuster(unfixed)end-of-life
xensourcebullseye4.14.5+94-ge49571868d-1DSA-5378-1
xensource(unstable)4.17.0+74-g3eac216e6e-11033297

Notes

[buster] - xen <end-of-life> (DSA 4677-1)
https://www.openwall.com/lists/oss-security/2023/03/21/1
https://xenbits.xen.org/xsa/advisory-427.html

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