# DF-1433 — 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

radeon_wb_init (:453-488): wb_ptr=NULL declared at :454. Only assigned inside if(wb_obj==NULL) block at :477. On resume/reset, wb_obj survives (wb_disable only clears enabled flag). memset(*(void**)wb_ptr,...) at :488 derefs NULL → panic. DFly-specific regression: upstream uses memset(rdev->wb.wb,...) directly.

**Source:** `sys/dev/drm/radeon/radeon_device.c:453-488`

## Why it cannot be reproduced on this guest

HW-gated. radeon.ko requires ATI/AMD GPU. Triggered by S3/S4 resume or GPU reset recovery.

## Phase 6: Escalation Assessment

This is a **HW-gated GPU module (radeon device)** 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

Remove wb_ptr indirection entirely; use rdev->wb.wb directly in radeon_bo_kmap and memset.

**Fix description:** Remove wb_ptr local; pass &rdev->wb.wb to radeon_bo_kmap and use rdev->wb.wb directly in memset.

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)