DF-0723

Error-path kfree uses wrong malloc type M_NETGRAPH_SPPP for M_IFNET allocation and bypasses if_free (LATENT — file does not compile)

Summary

LATENT — file does not compile (DF-0721). ng_sppp.c:249 ifp=if_alloc(IFT_PPP) allocates M_IFNET (if.c:3086). :261-262 error path kfree(pp,M_NETGRAPH_SPPP) where pp=(struct sppp*)ifp same pointer — frees M_IFNET allocation with wrong type tag. Also bypasses if_free() which shutdown :396 uses correctly. Corrupts malloc-type accounting leaks if_l2com if IFT_PPP ever gains com_alloc hook. Reachable on M_NULLOK OOM only. Fix: if_free(ifp) instead of kfree(pp,M_NETGRAPH_SPPP).

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Severity: Low
Status: new
Bucket: Base system — network stack
Confidence: likely
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U:C:N/I:N/A:L
CWE: CWE-763 Release of Invalid Pointer
File: sys/netgraph7/ng_sppp.c
Lines: 261-262
Area: net
Discovered: 2026-07-03
Updated: 2026-07-03

Team triage

untriaged

priority: — · owner: —

PoC verification

inconclusive

Status: inconclusive
Reproduced: no
Impact: dos
Confidence: likely
Tested: 2026-07-23 07:34:36
Attempts: 1
Runtime: —
Code hash: adfa6ca2192319b8
Guest: DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026
Build cmd: n/a (source-only)
Run cmd: n/a (source-only)

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PoC verification

Evidence pack

findings/poc/DF-0723 · 4 files

File	Type	Description	Size
VERDICT.md	verdict	source-confirmation + fix	967 B	↓ 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-0723 — Low-severity source-confirmation

Verdict: INCONCLUSIVE

Impact: dos Confidence: likely

Kernel ref: netgraph7/ng_sppp.c:261

Mechanism / why

LATENT: file does not compile (DF-0721); ng_sppp.c ifp=if_alloc() then on the error path kfrees(pp) without if_free(ifp) -> leaked ifnet. Source-confirmed in a non-compiling module.

Recommended fix

if_free(ifp) on the error path.

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).

Confirmed kernel references

Detail

Exploit chain

none (latent; source-confirmed)

Evidence (decisive lines)

DF-0723 [INCONCLUSIVE] - netgraph7/ng_sppp.c:261

PoC changes

fix.diff documented (fix in verdict) in findings/poc/DF-0723/; batched into ../_batch_low/combined_all.patch

Verified recommended fix

if_free(ifp) on the error path.

Verdict

LATENT: file does not compile (DF-0721); ng_sppp.c ifp=if_alloc() then on the error path kfrees(pp) without if_free(ifp) -> leaked ifnet. Source-confirmed in a non-compiling module.