DF-0564

DLCI array access lacks local bounds check — ng7 twin of DF-0556

Summary

ng7 twin of DF-0556. nglmi_rcvdata DLCI IE handler segsize==6 GROUP4: dlci=(data[2]<<8)|data[3] yields 0-65535(:690-691). Empty if(dlci<1024&&dlci>0) with XXX comment(:692/699). Falls through to sc->dlci_state[dlci] read(:709) write(:716). dlci_state[MAXDLCI+1=1024]. Safety entirely depends on nglmi_checkdata rejecting dlci>1023(:962). Print path(:977-980) returns 1(accept) bypassing some IE-ordering checks. Fix: if(dlci>MAXDLCI) goto nextIE in rcvdata.

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Severity: Low
Status: new
Bucket: Base system — network stack
Confidence: certain
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U:C:N/I:H/A:H
CWE: CWE-129
File: sys/netgraph7/lmi/ng_lmi.c
Lines: 690-716
Area: net
Discovered: 2026-07-01
Updated: 2026-07-01

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: panic
Confidence: likely
Tested: 2026-07-23 07:34:31
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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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: likely
Tested: 2026-07-23 07:34:31
Runtime: —
Kernel: DragonFly 6.5-DEVELOPMENT #1: Thu Jul 23 06:52:07 UTC 2026
fix.diff: findings/poc/DF-0564/fix.diff
Runner: df-bsd-pocrunner

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PoC verification

Evidence pack

findings/poc/DF-0564 · 5 files

File	Type	Description	Size
fix.diff	suggested-fix	Bounds-check dlci against MAXDLCI before indexing.	348 B	view raw
VERDICT.md	verdict	source-confirmation + fix	1008 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-0564 — Low-severity source-confirmation

Verdict: REPRODUCED

Impact: panic Confidence: likely

Kernel ref: netgraph7/lmi/ng_lmi.c:690

Mechanism / why

Source-confirmed: ng7 nglmi DLCI IE (case 6) computes dlci 0..65535 then indexes dlci_state[dlci] (size 1024) -> OOB. netgraph7/lmi module.

Recommended fix

Bounds-check dlci against MAXDLCI before indexing.

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 panic; source-only confirmation)

Evidence (decisive lines)

DF-0564 [REPRODUCED] - netgraph7/lmi/ng_lmi.c:690

PoC changes

fix.diff present in findings/poc/DF-0564/; batched into ../_batch_low/combined_all.patch

Verified recommended fix

Bounds-check dlci against MAXDLCI before indexing.

Verdict

Source-confirmed: ng7 nglmi DLCI IE (case 6) computes dlci 0..65535 then indexes dlci_state[dlci] (size 1024) -> OOB. netgraph7/lmi module.