# DF-1993 - Source Verification

## Verdict: REPRODUCED (source-only confirmation)

**Finding**: sys/dev/netif/ath/ath/if_ath_btcoex.c:407-410

**Mechanism**: ath_btcoex_ioctl: after switch sets error=EINVAL, copyout(outdata,...) executes unconditionally — copies entire uninitialized kmalloc'd buffer to userspace. No if(error) goto bad guard.

**Hardware dependency**: Requires ath(4) with BTCOEX support + ATH_DIAGAPI.

**Fix**: Add if(error) goto bad before the copyout.

## Verification method
Source-only confirmation. The cited code path was traced line-by-line in the
audited sys/ tree. The bug exists exactly as described. This is a HW-gated
driver finding — the vulnerable code path requires specific hardware (GPU,
controller, PHY, TPM, etc.) not present in the QEMU audit guest. Runtime
reproduction on this guest is not possible without the hardware.

## Fix validation
fix.diff authored and applied to guest source. All 40 fixes in this batch
compile cleanly in a single combined kernel build: `make -j6 nativekernel
KERNCONF=X86_64_GENERIC` → rc=0, zero -Werror violations.

**Kernel**: DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026