DescriptionIn the Linux kernel, the following vulnerability has been resolved: drm/mediatek: Init `ddp_comp` with devm_kcalloc() In the case where `conn_routes` is true we allocate an extra slot in the `ddp_comp` array but mtk_drm_crtc_create() never seemed to initialize it in the test case I ran. For me, this caused a later crash when we looped through the array in mtk_drm_crtc_mode_valid(). This showed up for me when I booted with `slub_debug=FZPUA` which poisons the memory initially. Without `slub_debug` I couldn't reproduce, presumably because the later code handles the value being NULL and in most cases (not guaranteed in all cases) the memory the allocator returned started out as 0. It really doesn't hurt to initialize the array with devm_kcalloc() since the array is small and the overhead of initting a handful of elements to 0 is small. In general initting memory to zero is a safer practice and usually it's suggested to only use the non-initting alloc functions if you really need to. Let's switch the function to use an allocation function that zeros the memory. For me, this avoids the crash.
SourceCVE (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 PackageReleaseVersionStatus
linux (PTS)bullseye5.10.218-1fixed
bullseye (security)5.10.221-1fixed
bookworm (security)6.1.90-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebuster(not affected)
linuxsourcebullseye(not affected)
linuxsourcebookworm(not affected)


[bookworm] - linux <not-affected> (Vulnerable code not present)
[bullseye] - linux <not-affected> (Vulnerable code not present)
[buster] - linux <not-affected> (Vulnerable code not present) (6.10-rc1)

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