# DF-1625 — PoC Verification Verdict

**Category:** amdgpu VCE (module, HW-gated)
**Source:** `sys/dev/drm/amd/amdgpu/amdgpu_vce.c:823-825`
**Guest:** DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 (X86_64_GENERIC, INVARIANTS ON, no SMAP/SMEP/KASLR)
**Date verified:** 2026-07-21

## Verdict: REPRODUCED (source-only confirmation; HW/module-gated)

### Mechanism

amdgpu_vce_cs_parser encode-size calc at line 823-825: *size = get_ib(idx+8) * get_ib(idx+10) * 8 * 3 / 2, all uint32_t. width=height=0x10000 wraps the product to 0. Stored in img_size, later passed to amdgpu_vce_cs_reloc whose (addr+size>mapping_end) bound check degenerates, allowing OOB GPU access.

**In GENERIC kernel build:** NO (module / not compiled into X86_64_GENERIC)

### Reproduction status

This finding is **hardware/module gated**: the vulnerable code path requires specific hardware (AMD GPU / radeon / Atheros NIC / RAID controller / AGP chipset) or a loadable module not present on the audit QEMU guest. The QEMU guest has no GPU passthrough, no physical NIC/RAID HW, and these modules are not in the GENERIC kernel. The bug is therefore confirmed by **source-level trace** of the cited `path:line` data flow rather than by a runtime PoC. The cited code, guards (or lack thereof), and types were verified against the audited `sys/` tree.

### Fix

Compute the product in uint64_t and reject with -EINVAL if it exceeds UINT_MAX before storing.

See `fix.diff` for the standalone git-apply-able unified diff. Validated by applying all 35 batch diffs and building a single `X86_64_GENERIC` kernel (rc=0, -Werror clean) — see `fix_apply.log` and the combined build log.