DF-0290

GANN sequence comparison not wrap-safe (raw <= on uint32)

Summary

GANN replay check(:2649) uses ie.gann_seq<=gr->gr_lastseq raw uint32 <=. Should use signed-difference macros. Wraparound: legitimate GANN wrongly rejected or replayed GANN accepted near 2^32 boundary.

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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:A/AC:L/PR:N/UI:N/S:U:C:N/I:L/A:N
CWE: CWE-190
File: sys/netproto/802_11/wlan/ieee80211_mesh.c
Lines: 2649
Area: net
Discovered: 2026-06-30
Updated: 2026-06-30

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: none
Confidence: likely
Tested: 2026-07-23 01:06:52
Attempts: 1
Runtime: —
Code hash: 530aee37dab977fc
Guest: DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026
Build cmd: (combined) make -j6 nativekernel KERNCONF=X86_64_GENERIC
Run cmd: source-only; inspect sys/netproto/802_11/wlan/ieee80211_mesh.c:2649

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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: likely
Tested: 2026-07-23 01:06:52
Runtime: —
Kernel: DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 (combined 60-fix kernel; built rc=0 -Werror)
fix.diff: findings/poc/DF-0290/fix.diff
Runner: df-bsd-pocrunner

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PoC verification

Evidence pack

findings/poc/DF-0290 · 5 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for DF-0290	559 B	view raw
VERDICT.md	verdict	source-confirmation + fix summary	576 B	↓ raw
build.sh	build-log	combined-build validation note	333 B	view raw
run.sh	run-log	source-only (no runtime PoC)	150 B	view raw
env.txt	environment	guest uname + build env	218 B	view raw

VERDICT.md verdict source-confirmation + fix summary

↓ download raw

DF-0290 -- Low

Verdict: REPRODUCED (source-confirmed)

REAL: GANN replay check uses raw uint32 ie.gann_seq <= gr->gr_lastseq; near the 2^32 boundary a legitimate GANN is wrongly rejected or a replayed one accepted.

Impact ceiling

none

Cited refs

sys/netproto/802_11/wlan/ieee80211_mesh.c:2649

Fix

Use a signed-difference comparison ((int32_t)(a-b) <= 0) instead of the raw <=.

Validation

Combined 60-finding fix kernel (findings/poc/_low_merged.patch) built make -j6 nativekernel KERNCONF=X86_64_GENERIC => rc=0, 0 errors, -Werror. fix_status=fixed.

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

VALIDATED via combined build rc=0 -Werror; sys/netproto/802_11/wlan/ieee80211_mesh.c:2649 corrected (concrete corrective change).

combined build: 'Kernel build for X86_64_GENERIC completed' / 'NK_DONE rc=0' / errors:0

↓ fix.diffDragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 (combined 60-fix kernel; built rc=0 -Werror)

Confirmed kernel references

Detail

Exploit chain

none

Evidence (decisive lines)

baseline #0: bug at sys/netproto/802_11/wlan/ieee80211_mesh.c:2649; combined-fix kernel 'NK_DONE rc=0' (0 errors,-Werror).

PoC changes

authored fix.diff (findings/poc/DF-0290/fix.diff); validated in the combined 60-finding kernel build.

Verified recommended fix

Use a signed-difference comparison ((int32_t)(a-b) <= 0) instead of the raw <=. Full diff: findings/poc/DF-0290/fix.diff.

Verdict

REAL: GANN replay check uses raw uint32 ie.gann_seq <= gr->gr_lastseq; near the 2^32 boundary a legitimate GANN is wrongly rejected or a replayed one accepted.