# DF-3301 -- VERDICT

**REPRODUCED** (impact=none, confidence=certain)
Guest: DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026  root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64

## Summary
CARP HMAC key = raw zero-padded ASCII passphrase, no KDF anywhere: four captured advertisements (vhid 1, pass test123) ALL authenticate under HMAC-SHA1 with key b"test123"+13x00 (construction recomputed independently from carp_hmac_prepare/generate). A user choosing a weak passphrase gets exactly its low-entropy bytes as a 20-byte HMAC key.

## How it was verified
- Method: Live PoC on the QEMU guest (stock INVARIANTS kernel)
- Kernel references: sys/netinet/ip_carp.c:2476-2538, sys/netinet/ip_carp.c:504-554, sys/netinet/ip_carp.c:556-575
- Evidence: carp_verify.txt (fresh capture): 4/4 packets match HMAC(zero-padded ASCII); live4.log tcpdump lines
- Reachability: local-unpriv where noted in the summary; root-config for tun/lagg/carp/ipfw3/gre items; remote-facing for the packet parsers (wlan harnesses model the RX/TX path verbatim because the guest has no 802.11 hardware; precedent DF-0393/DF-0594/DF-0621/DF-0350).
- Privesc assessment: no uid0 chain exists for any finding in this batch -- the memory-safety items are bounded info reads (kernleak bucket) or fault-injection-gated NULL derefs; nothing yields a write primitive or control over privileged state. The one panic-class live item (DF-3414) is root-only (SIOCIFDESTROY).

## Fix
fix_status: not_testable -- Fix would be a KDF (e.g. SHA1-stretch) in ifconfig/carp key setup - a userland+kernel compatibility change, out of scope for a guest A/B here.



## Fix status (batch validation)
Applied with the 36 sibling fix.diffs of this batch in findings/poc/_batch41/all_fixes.patch; single in-guest `make -j6 nativekernel KERNCONF=X86_64_GENERIC` completed RC=0 with zero errors under -Werror (full log: findings/poc/_batch41/fix_build8.log). Behavior A/B intentionally skipped for this Info-tier item.

(No fix.diff for this item: documented recommendation only - see Fix above.)