# DF-1815 Verification

## Verdict
**SOURCE-CONFIRMED, INCONCLUSIVE-RUNTIME (HW/module gated).**

The cited defect exists in the audited source at `sys/dev/drm/amd/powerplay/hwmgr/ppatomfwctrl.c:33-47`. Reproduction
on the running guest is **not possible** because the affected code path is
gated behind hardware that is not present in the audit QEMU/KVM guest
(no AMD/i915 GPU, no LSI MegaRAID, no MMC/SDHCI controller, no FireWire, no
ATAPI floppy, etc.) and/or lives in a kernel module that is not loaded on the
GENERIC-running guest.

## Mechanism (source-only confirmation)
AMD GPU powerplay (not in GENERIC, no AMD HW). Source: voltage_object_info_table walk uses attacker-controlled `structuresize` (le16 from VBIOS) as the upper bound at L39 with no in-bounds check against the actual allocation, and uses `object_size` (le16) as the stride at L47; object_size==0 causes infinite loop, large values OOB. Confirmed in source.

## Recommended fix
Declare obj_size, break the walk on zero stride (defends against infinite loop / OOB read past the VBIOS table).

The full `git apply`-able diff lives in `fix.diff` in this folder; it was
applied as part of a single combined 41-finding kernel build that compiled
cleanly (rc=0, -Werror clean) — see `../fix_build_summary.txt`.

## Build validation
* `git apply --check` on this fix.diff: **OK**
* Combined kernel build (`X86_64_GENERIC`, INVARIANTS ON) with all 41
  findings' fix.diffs applied: **rc=0**, no warnings, no errors.
* The patched kernel was not booted/run because the affected code path
  requires hardware that the audit guest does not have.