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DF-2589

Unchecked AcpiEvaluateObject return in acpi_panasonic_sinf causes NULL-deref panic and heap OOB read

Summary

acpi_panasonic_sinf calls AcpiEvaluateObject for SINF never checks ACPI_STATUS return. On failure buf.Pointer NULL res->Type(:279) guaranteed NULL-deref panic. Even on success if package < index+1 elements line :280 reads past heap Elements array no Package.Count check. Reachable by any unpriv local user via 4 CTLFLAG_ANYBODY sysctl nodes hw.acpi.panasonic.*lcd_brightness _max _min sound_mute. Canonical pattern in acpi.c:2902-2908 checks ACPI_FAILURE res==NULL ACPI_PKG_VALID. Panasonic driver does none.

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PoC verification

Evidence pack

findings/poc/DF-2589 · 5 files
FileTypeDescriptionSize
VERDICT.md verdict analysis: code bug confirmed, gate confirmed, fix authored 1.6 KB ↓ raw
fix.diff suggested-fix git-apply-able defense-in-depth fix (verified --check clean) 677 B view raw
env.txt environment guest gate-proof: usbconfig/pciconf/ifconfig/devinfo/sysctl output 2.0 KB view raw
build.sh build-script no-op (no live-device PoC) 255 B view raw
run.sh run-script gate check (required device is absent) 333 B view raw
VERDICT.md verdict analysis: code bug confirmed, gate confirmed, fix authored
↓ download raw

DF-2589 — PoC verdict

File: sys/dev/acpica/acpi_panasonic/acpi_panasonic.c

Verdict: NOT REPRODUCED on this QEMU guest — confirmed HW/ACPI/device-gated; the code bug is REAL and a defense-in-depth fix.diff is attached.

Mechanism (confirmed in source)

acpi_panasonic_sinf() calls AcpiEvaluateObject("SINF") without checking the ACPI_STATUS return; on failure buf.Pointer is NULL and res->Type (line 279) is a guaranteed NULL-deref panic. Even on success, line 280 reads res->Package.Elements[index] with no Package.Count check (OOB heap read if the package has fewer than index+1 elements). Reachable via four CTLFLAG_ANYBODY sysctl nodes.

Cited lines

Why it does not reproduce on this guest

No Panasonic ACPI SINF device on the QEMU/BOCHS guest (sysctl hw.acpi.panasonic -> unknown oid; module not loaded).

Guest gate-proof (full usbconfig/pciconf/ifconfig/devinfo/sysctl/kldstat output) is in env.txt.

Defense-in-depth fix

Check ACPI_FAILURE(status) and return early; validate res!=NULL, res->Type==ACPI_TYPE_PACKAGE, and indexPackage.Count before the element access.

The git-apply-able diff is in fix.diff (verified git apply --check clean).

Classification

  • status: not_reproduced
  • reproduced: 0
  • impact: none (not reachable on this guest; latent code bug confirmed in source)
  • confidence: certain (code bug + gate both confirmed by direct source trace and guest enumeration)
  • fix_status: not_testable (patch applies + compiles-correct by inspection, but no live device to exercise on this guest)

Fix verification

not_testable
baseline no→ patch + rebuild →patched clean

not_testable: target device absent on this guest. fix.diff applies clean and is source-correct; no live device to exercise.

git apply --check findings/poc/DF-2589/fix.diff -> OK. No runtime test possible (HW/ACPI/device-gated).
↓ fix.diffper-fix-DF-2589

Confirmed kernel references

Detail

Exploit chain

none — valid hard blocker (driver/device path dead at runtime on this guest: no target HW/ACPI/device). No unprivileged->root path.

Evidence (decisive lines)

usbconfig list -> No device match; pciconf -l -> no target HW/capability; ifconfig -> vtnet0 lo0; kldstat -> kernel/ehci/xhci only; sysctl/devinfo -> no target OIDs. Source confirmed at cited lines.

PoC changes

Created findings/poc/DF-2589/{VERDICT.md,fix.diff,manifest.json,env.txt,build.sh,run.sh}. No PoC source (HW/ACPI/device-gated).

Verified recommended fix

Defense-in-depth fix.diff closes the cited path (see findings/poc/DF-2589/fix.diff; git apply --check OK).

Verdict

NOT REPRODUCED (HW/ACPI/device-gated on this guest). The bug is REAL in source (traced line-by-line): acpi_panasonic unchecked AcpiEvaluateObject return (Panasonic ACPI only). Gate confirmed via usbconfig list (no devices), pciconf -l (no target HW/capability), ifconfig (vtnet0 lo0 only), kldstat (no target module), sysctl/devinfo (no target ACPI/device OIDs). The benign QEMU environment cannot produce the malicious device/ACPI/descriptor the bug requires.