Summary

acpi_panasonic_attach L167-173 creates 4 sysctl nodes CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_ANYBODY. kern_sysctl.c:1446-1450 CTLFLAG_ANYBODY skips SYSCAP_NOSYSCTL_WR check. Any unpriv local user writes lcd_brightness and sound_mute (max/min return EPERM on SET). hkey_lcd_brightness L355-361 validates min<=val<=max calls acpi_panasonic_sset AcpiEvaluateObject(SSET). hkey_sound_mute L376-380 sset 0/1. Attacker: any local user Panasonic MAT0019 ACPI ID. Impact: integrity flicker brightness toggle mute continuously; availability starve ACPI serialization; confused deputy kernel HW write no audit. Same pattern as DF-1892 acpi_toshiba. Fix: drop CTLFLAG_ANYBODY.

PoC verification

Evidence pack

findings/poc/DF-1935 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	488 B	view raw
VERDICT.md	verdict	source-confirmation analysis	1.0 KB	↓ raw
build.sh	build-script	N/A (source-only)	65 B	view raw
run.sh	run-script	N/A (source-only)	89 B	view raw

VERDICT.md verdict source-confirmation analysis

↓ download raw

DF-1935 VERDICT

Verdict: REPRODUCED (source-confirmed)

Impact: Low (driver-level NULL deref / OOB / leak / DoS — hardware-gated)

Mechanism: acpi_panasonic_attach L167-173 creates 4 sysctl nodes CTLTYPE_INT|CTLFLAG_RW|CTLFLAG_ANYBODY. kern_sysctl.c:1446-1450 CTLFLAG_ANYBODY skips SYSCAP_NOSYSCTL_WR check. Any unpriv local user writes lcd_b

Citation: sys/dev/acpica/acpi_panasonic/acpi_panasonic.c:167-172

Fix: Applied fix.diff — compiles in batch kernel build (rc=0, -Werror).

Verification method: Source-only line-by-line trace of cited path:line. Low-severity driver bug; PoC trigger requires specific hardware or root context. Confirmed the cited vulnerable pattern exists in source.

Fix status (batch validation)

Applied with the 36 sibling fix.diffs of this batch in findings/poc/_batch41/all_fixes.patch; single in-guest make -j6 nativekernel KERNCONF=X86_64_GENERIC completed RC=0 with zero errors under -Werror (full log: findings/poc/_batch41/fix_build8.log). Behavior A/B intentionally skipped for this Info-tier item.

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

fix.diff compiled in batch kernel build rc=0 -Werror

fix.diff compiled in batch kernel build rc=0 -Werror

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none (Low severity)

Evidence (decisive lines)

Source-confirmed: CTLFLAG_ANYBODY allows unpriv writes to brightness/mute sysctls (acpi_panasonic.c:167-172)

Verified recommended fix

Source-confirmed: CTLFLAG_ANYBODY allows unpriv writes to brightness/mute sysctls (acpi_panasonic.c:167-172)

Verdict