CVE-2021-3308

NameCVE-2021-3308
DescriptionAn issue was discovered in Xen 4.12.3 through 4.12.4 and 4.13.1 through 4.14.x. An x86 HVM guest with PCI pass through devices can force the allocation of all IDT vectors on the system by rebooting itself with MSI or MSI-X capabilities enabled and entries setup. Such reboots will leak any vectors used by the MSI(-X) entries that the guest might had enabled, and hence will lead to vector exhaustion on the system, not allowing further PCI pass through devices to work properly. HVM guests with PCI pass through devices can mount a Denial of Service (DoS) attack affecting the pass through of PCI devices to other guests or the hardware domain. In the latter case, this would affect the entire host.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium
Debian Bugs981052

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
xen (PTS)stretch (security), stretch4.8.5.final+shim4.10.4-1+deb9u12fixed
buster4.11.4+99-g8bce4698f6-1fixed
buster (security)4.11.4+107-gef32c7afa2-1fixed
bullseye, sid4.14.1+11-gb0b734a8b3-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
xensourcestretch(not affected)
xensourcebuster(not affected)
xensource(unstable)4.14.1+11-gb0b734a8b3-1981052

Notes

[buster] - xen <not-affected> (Vulnerable code introduced later)
[stretch] - xen <not-affected> (Vulnerable code introduced later)
https://xenbits.xen.org/xsa/advisory-360.html
Introduced by: https://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=5b58dad089880127674d460494d1a9d68109b3d7 (4.14.0-rc1)
Issue backported to 4.12.3 and 4.13.1
Fixed by: https://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=58427889f5a420cc5226f88524b3228f90b72a58

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