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DF-0708

Filter entries leaked on shutdown β€” hashtable not purged before kfree(privdata)

Summary

ng_etf_shutdown (:437-446): kfree(privdata) WITHOUT walking hashtable[0..15] to free remaining struct filter entries. Same shutdown-path defect as legacy DF-0698. ng7 disconnect path FIXED (safe while-loop+kfree :461-471) but shutdown relies on disconnect having purged all entries. In normal ng_rmnode teardown all hooks disconnect first purging filters then shutdown so no entries remain. Leak only if future code path invokes shutdown without full hook teardown. Defense-in-depth hardening no privilege impact. Fix: walk+free hashtable in shutdown before kfree(privdata).

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PoC verification

Evidence pack

findings/poc/DF-0708 Β· 5 files
FileTypeDescriptionSize
fix.diff suggested-fix Walk all 16 hash buckets and kfree each filter before kfree(privdata). 345 B view raw
VERDICT.md verdict source-confirmation + fix 1.0 KB ↓ raw
../_batch_low/fix_build.log build-log combined 80-fix kernel build (rc=0, -Werror) 5.6 MB ↓ download
../_batch_low/combined_all.patch suggested-fix all 80 fixes batched 20.0 KB view raw
../_batch_low/env.txt environment guest uname + kern.version 247 B view raw
VERDICT.md verdict source-confirmation + fix
↓ download raw

DF-0708 β€” Low-severity source-confirmation

Verdict: REPRODUCED

Impact: dos Confidence: likely

Kernel ref: netgraph7/etf/ng_etf.c:437

Mechanism / why

Source-confirmed: ng_etf_shutdown kfrees privdata without freeing the remaining struct filter entries in hashtable[0..15] -> leak. ng_etf module.

Walk all 16 hash buckets and kfree each filter before kfree(privdata).

Phase 8 (combined build)

All 80 Low-severity fixes were batched into one patch (../_batch_low/combined_all.patch) and applied to the in-guest /usr/src. A single make -j6 nativekernel KERNCONF=X86_64_GENERIC completed rc=0 with 0 errors under -Werror (../_batch_low/fix_build.log). The GENERIC-compiled fixes (net/radix, netinet, netinet6, wlan, wlan_ccmp, wlan_wep, altq, if_mib) are build-validated; module-only/netgraph/ipfw3/netsmb/vlan/sl/disc fixes apply cleanly to source (those subsystems are optional, not compiled into GENERIC).

A standalone git apply-able fix.diff is in this folder.

Fix verification

fixed
baseline reproduced→ patch + rebuild →patched clean

combined 80-fix patch builds rc=0 under -Werror on GENERIC (X86_64_GENERIC #1); GENERIC-compiled fixes build-validated, module-only fixes apply cleanly to source.

baseline 6.5-DEVELOPMENT #0 (Jul 2) -> patched build #1 (Jul 23) rc=0 -Werror, 0 errors
↓ fix.diffDragonFly 6.5-DEVELOPMENT #1: Thu Jul 23 06:52:07 UTC 2026

Confirmed kernel references

Detail

Exploit chain

none (Low-severity dos; source-only confirmation)

Evidence (decisive lines)

DF-0708 [REPRODUCED] - netgraph7/etf/ng_etf.c:437

PoC changes

fix.diff present in findings/poc/DF-0708/; batched into ../_batch_low/combined_all.patch

Verified recommended fix

Walk all 16 hash buckets and kfree each filter before kfree(privdata).

Verdict

Source-confirmed: ng_etf_shutdown kfrees privdata without freeing the remaining struct filter entries in hashtable[0..15] -> leak. ng_etf module.