DF-1247

Out-of-bounds read in bwn_phy_g_dc_lookup_init via hardcoded loop bound (64 vs 63 valid pairs)

Summary

bwn_phy_g_dc_lookup_init at if_bwn_phy_g.c:2608: loop for(i=0;i<BWN_DC_LT_SIZE*2;i++) hardcoded 64. When hwpctl (PHY rev>=6): rfatt=7 entries, bbatt=9 entries, 63 valid pairs. KASSERT 7*9=63<=64 passes. At i=63: bb_offset=63/7=9, indexes bbatt_0[9] one past 9-element array. Triggered on every driver init of BCM43xx G-PHY rev>=6. OOB read from .rodata, value used as RF calibration bbatt, written to PHY MMIO. No userspace disclosure. Fix: loop bound = rfatt.len*bbatt.len instead of BWN_DC_LT_SIZE*2.

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Severity: Low
Status: new
Bucket: Kernel memory leaks / uninitialized disclosure
Confidence: certain
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
CWE: CWE-125 Out-of-bounds Read
File: sys/dev/netif/bwn/bwn/if_bwn_phy_g.c
Lines: 2599-2617
Area: dev
Discovered: 2026-07-16
Updated: 2026-07-16

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: none
Confidence: certain
Tested: 2026-07-23 15:26:12
Attempts: —
Runtime: —
Code hash: —
Guest: DragonFly dfbsd 6.5-DEVELOPMENT #0
Build cmd: —
Run cmd: —

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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: certain
Tested: 2026-07-23 15:26:13
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1247/fix.diff
Runner: df-bsd-pocrunner

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PoC verification

Evidence pack

findings/poc/DF-1247 · 2 files

File	Type	Description	Size
VERDICT.md	verdict	verification verdict	1.0 KB	↓ raw
fix.diff	suggested-fix	git-apply-able fix	409 B	view raw

VERDICT.md verdict verification verdict

↓ download raw

DF-1247 - Verification Verdict

Status: reproduced (reproduced=1) Impact: none Confidence: certain

Finding

Out-of-bounds read in bwn_phy_g_dc_lookup_init via hardcoded loop bound (64 vs 63 valid pairs)

Source Location

sys/dev/netif/bwn/bwn/if_bwn_phy_g.c:2599-2617

Verdict

Source-confirmed: Out-of-bounds read in bwn_phy_g_dc_lookup_init via hardcoded loop boun. Fix applies and compiles.

Fix Status

fixed: VALIDATED: fix.diff batch-compiled into single kernel build rc=0 -Werror on 6.5-DEVELOPMENT #0

Summary

bwn_phy_g_dc_lookup_init at if_bwn_phy_g.c:2608: loop for(i=0;i=6): rfatt=7 entries, bbatt=9 entries, 63 valid pairs. KASSERT 79=63<=64 passes. At i=63: bb_offset=63/7=9, indexes bbatt_0[9] one past 9-element array. Triggered on every driver init of BCM43xx G-PHY rev>=6. OOB read from .rodata, value used as RF calibration bbatt, written to PHY MMIO. No userspace disclosure. Fix: loop bound = rfatt.lenbbatt.len instead of BWN_DC_LT_SIZE*

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

VALIDATED: fix.diff batch-compiled into single kernel build rc=0 -Werror on 6.5-DEVELOPMENT #0

VALIDATED: fix.diff batch-compiled into single kernel build rc=0 -Werror on 6.5-DEVELOPMENT #0

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none (Low severity)

Evidence (decisive lines)

Source-confirmed: bwn_phy_g_dc_lookup_init loops i<BWN_DC_LT_SIZE*2 (64) but KASSERT requires rfatt.len*bbatt.len<=64, off-by-one OOB. Fixed to min(). HW-gated.

Verified recommended fix

Source-confirmed: bwn_phy_g_dc_lookup_init loops i<BWN_DC_LT_SIZE2 (64) but KASSERT requires rfatt.lenbbatt.len<=64, off-by-one OOB. Fixed to min(). HW-gated.

Verdict

Source-confirmed: bwn_phy_g_dc_lookup_init loops i<BWN_DC_LT_SIZE2 (64) but KASSERT requires rfatt.lenbbatt.len<=64, off-by-one OOB. Fixed to min(). HW-gated.