Summary

acpi_hp.c:847 obj->Type == ACPI_TYPE_BUFFER check but NO Buffer.Length >= 3*sizeof(UINT32). result = obj->Buffer.Pointer; result[2] and result[1] read as UINT32. Short buffer (0/4/8B) -> OOB read past AcpiOsAllocate allocation into adjacent kernel heap. retval exposed via sysctl as int -> small heap leak. Or panic on unmapped page. BIOS-dependent: needs buggy/malicious SSDT returning short WQxx buffer. Fix: check Buffer.Length >= 12.

PoC verification

Evidence pack

findings/poc/DF-1608 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	423 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-1608 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: acpi_hp.c:847 obj->Type == ACPI_TYPE_BUFFER check but NO Buffer.Length >= 3*sizeof(UINT32). result = obj->Buffer.Pointer; result[2] and result[1] read as UINT32. Short buffer (0/4/8B) -> OOB read past

Citation: sys/dev/acpica/acpi_hp/acpi_hp.c:847-855

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: result[2] read without buffer length >=12 check (acpi_hp.c:847-855)

Verified recommended fix

Source-confirmed: result[2] read without buffer length >=12 check (acpi_hp.c:847-855)

Verdict