# DF-3409 -- VERDICT

**NOT 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
tuncreate publishes dev->si_drv1 = sc BEFORE if_alloc and never rolls back on failure (if_tun.c:213-242) - the half-built softc would later NULL-deref in tunifioctl (sc->tun_ifp == NULL). However the trigger is unreachable in practice: if_alloc(IFT_PPP) is a plain M_WAITOK kmalloc with no com_alloc hook (if.c if_alloc), so it cannot fail short of a sleeping allocation failure the kernel does not surface. Mechanism line-confirmed; no live/harness trigger.

## How it was verified
- Method: Code-line analysis + attempted live reproduction
- Kernel references: sys/net/tun/if_tun.c:213-242, sys/net/if.c:if_alloc
- Evidence: VERDICT.md: if_alloc excerpt (M_WAITOK, IFT_PPP has no com_alloc) - failure path unreachable
- 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: on if_alloc failure, kfree(sc) and clear dev->si_drv1 before returning NULL; trigger unreachable, no A/B possible.



## 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.)