# DF-0750 source-confirmation

**Verdict:** REPRODUCED (source-confirmed)  
**Impact:** none  **Confidence:** likely

**Kernel ref:** `sys/net/ipfw3_layer2/ip_fw3_layer2.c:127`

## Mechanism
strncpy on binary MAC truncates at 0x00 byte -> wrong lookup key

## Confirmation method
Source-trace confirmed the cited code path matches the finding (exact line/condition
verified against `sys/`). Runtime PoC not exercised for this source-only Low-severity
item; confirmation is by code inspection.

## Recommended fix
See `fix.diff` in this folder (git-apply-able unified diff).

## Phase 8 (combined build)
All 64 fixes were batched into one combined patch
(`../_batch/combined_64.patch`) and applied to in-guest `/usr/src`. A single
`make -j6 nativekernel KERNCONF=X86_64_GENERIC` completed **rc=0 with 0 errors under
-Werror** (`../_batch/fix_build.log`, 35374 lines). The GENERIC kernel + all modules
(drm, firewire, usb, netgraph, smbfs, fuse, crypto, vm, pmap) compiled clean.