# DF-1414 — Verification Verdict

## Verdict: CONFIRMED-BY-SOURCE-TRACE (HW-gated)

**Status:** inconclusive (HW-gated / not reachable as unprivileged maxx)
**Impact:** none (cannot reproduce on QEMU guest — no GPU/HW, or root/operator-only)
**Confidence:** certain (source-trace confirmed bug is real)

## Mechanism

display_object_info_table_v1_4 has display_path[8] but number_of_path is u8 (0-255). 7 consumers loop i<number_of_path (get_connectors_number :162, get_connector_id :179, get_src_obj :214/229, get_bios_object :261/273, get_bracket_layout_record :1802). GET_IMAGE validates only sizeof(struct with 8 entries). number_of_path>8 → OOB read up to 3.9KB past validated window into BIOS heap. NOTE: finding cites bios_parser.c but the v1_4 consumers are in bios_parser2.c.

**Source:** `sys/dev/drm/amd/display/dc/bios/bios_parser2.c:162, 179, 214, 229, 261, 273, 1802`

## Why it cannot be reproduced on this guest

HW-gated. amdgpu display module requires AMD GPU. No GPU in QEMU guest.

## Phase 6: Escalation Assessment

This is a **HW-gated GPU module (amdgpu display DC BIOS)** finding. The primitive is not reachable from the
unprivileged maxx user on this guest (no hardware / module not loaded / root-only device).
No escalation chain is possible because the trigger path is not exercisable.

For GPU findings: the module (radeon.ko/amdgpu.ko/i915.ko) is a loadable module not
present in the GENERIC kernel and requires actual GPU hardware absent from the QEMU guest.
For root/operator findings: the device node is mode 0600 or 0640 root:operator, and maxx
(uid 1001) has no operator group membership.

## Fix

Clamp number_of_path to ARRAY_SIZE(display_path) (=8) before looping.

**Fix description:** Clamp number_of_path to ARRAY_SIZE(display_path) before iterating consumers.

The full git-apply-able diff is in `fix.diff`. It applies cleanly to the audit source tree
and compiles as part of the kernel build (validated via `make nativekernel` rc=0).

## Classification

- **status:** inconclusive
- **reproduced:** 0
- **impact:** none
- **fix_status:** not_testable (HW-gated: PoC cannot run on guest; diff applies + compiles verified)