# DF-2508 -- u32 overflow in afd_sense capabilities-path mediasize computation

Verification used the shared rig tree at /root/rigs on the audit
guest (see manifest).  The rig for this finding: dfv_afd  (rig.c = harness,
gen.sh = verbatim extractor, dfv_*_extract.h = generated production text).
The decisive outputs below were captured live on the guest during the
2026-10-24 verification session; full session logs are summarized per run.


## Build
    sh build.sh            # extracts verbatim driver text + builds the KLD

## Run (guest, root)
    kldload ./dfv_rig.ko
kldload dfv_afd.ko; for i in 0 1 2; do sysctl kern.dfv_afd_run=$i >/dev/null; sysctl -n kern.dfv_afd_status; done

## Expected
run.log: expected 0x7d81827e00 vs verbatim 0x81827e00 (exact low-32 truncation); fixed exact.

## Fix validation
fix.diff casts the first operand to u_int64_t before the product; A/B exact.

Verdict: reproduced / impact=corruption (see verdict.json, VERDICT.md)