CVE-2021-3444

NameCVE-2021-3444
DescriptionThe bpf verifier in the Linux kernel did not properly handle mod32 destination register truncation when the source register was known to be 0. A local attacker with the ability to load bpf programs could use this gain out-of-bounds reads in kernel memory leading to information disclosure (kernel memory), and possibly out-of-bounds writes that could potentially lead to code execution. This issue was addressed in the upstream kernel in commit 9b00f1b78809 ("bpf: Fix truncation handling for mod32 dst reg wrt zero") and in Linux stable kernels 5.11.2, 5.10.19, and 5.4.101.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-2785-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)jessie, jessie (lts)3.16.84-1vulnerable
stretch (security)4.9.320-2fixed
stretch (lts), stretch4.9.320-3fixed
buster4.19.249-2fixed
buster (security)4.19.316-1fixed
bullseye5.10.218-1fixed
bullseye (security)5.10.221-1fixed
bookworm6.1.94-1fixed
bookworm (security)6.1.99-1fixed
trixie6.9.8-1fixed
sid6.9.9-1fixed
linux-4.19 (PTS)stretch (security)4.19.232-1~deb9u1fixed
stretch (lts), stretch4.19.316-1~deb9u1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcejessie(unfixed)end-of-life
linuxsourcestretch(not affected)
linuxsourcebuster4.19.208-1
linuxsource(unstable)5.10.19-1
linux-4.19sourcestretch4.19.208-1~deb9u1DLA-2785-1

Notes

[stretch] - linux <not-affected> (Vulnerable code introduced later)
https://git.kernel.org/linus/9b00f1b78809309163dda2d044d9e94a3c0248a3
https://www.openwall.com/lists/oss-security/2021/03/23/2

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