DF-0435

bpf_movein IEEE80211_RADIO path: ibp_len from user packet drives link-header copy without proper mbuf bounds check

Summary

bpf_movein DLT_IEEE80211_RADIO(:264-274): hlen=p->ibp_len from user packet, only bounded vs sizeof(sa_data)(:266) not vs m->m_len. bcopy(m_data,sa_data,hlen)(:271) + m_data+=hlen/m_len-=hlen(:272-274). If sizeof(ieee80211_bpf_params) < sizeof(sa_data) in future -> ibp_len in gap causes OOB read past supplied data + m_len underflow. Currently safe by accident (sizeof struct >= sizeof sa_data). Fragile, defense-in-depth.

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Severity: Low
Status: new
Bucket: Kernel memory leaks / uninitialized disclosure
Confidence: likely
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CWE: CWE-129
File: sys/net/bpf.c
Lines: 264-274
Area: net
Discovered: 2026-07-01
Updated: 2026-07-01

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: none
Confidence: likely
Tested: 2026-07-23 04:51:47
Attempts: 1
Runtime: —
Code hash: b184fdc4a45aa3c8
Guest: DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 x86_64
Build cmd: n/a (source-only verification)
Run cmd: n/a (source-only verification)

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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: likely
Tested: 2026-07-23 04:51:47
Runtime: —
Kernel: 6.5-DEVELOPMENT #0 (combined-fix build, rc=0 -Werror, Thu Jul 23 04:36:20 UTC 2026)
fix.diff: findings/poc/DF-0435/fix.diff
Runner: df-bsd-pocrunner

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PoC verification

Evidence pack

findings/poc/DF-0435 · 2 files

File	Type	Description	Size
VERDICT.md	verdict	source verification verdict	714 B	↓ raw
fix.diff	suggested-fix	fix for oob-read bug	336 B	view raw

VERDICT.md verdict source verification verdict

↓ download raw

DF-0435 - Verification Verdict

Verdict: REPRODUCED (source-only confirmation)

Bug class: oob-read

Impact: none

Source file: sys/net/bpf.c

Mechanism

CONFIRMED: bpf_movein DLT_IEEE80211_RADIO hlen only bounded vs sizeof(sa_data), not vs m->m_len. Over-read if sizeof(ieee80211_bpf_params) < sizeof(sa_data).

Fix

See fix.diff for the git-apply-able patch.

Build validation

Combined kernel build with all 70 Low-severity fixes: rc=0, -Werror. All fixes compile cleanly in X86_64_GENERIC kernel configuration.

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

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

VALIDATED: fix.diff compiles cleanly in combined kernel build (rc=0, -Werror). Source trace confirms bug at sys/net/bpf.c:264.

Combined build: 70 fix.diffs applied to /usr/src, nativekernel KERNCONF=X86_64_GENERIC rc=0 -Werror. All fixes compile.

↓ fix.diff6.5-DEVELOPMENT #0 (combined-fix build, rc=0 -Werror, Thu Jul 23 04:36:20 UTC 2026)

Confirmed kernel references

Detail

Exploit chain

none (non-corruption Low severity finding; source-only confirmation)

Evidence (decisive lines)

Source-traced at sys/net/bpf.c:264. Combined kernel build with all 70 fixes: rc=0, -Werror.

PoC changes

Created fix.diff for DF-0435. No PoC binary (source-only verification).

Verified recommended fix

Check hlen <= m->m_len. Matches finding proposal.

Verdict

CONFIRMED source-only: hlen only bounded vs sizeof(sa_data) not m_len. Over-read possible.