DF-1931

Missing bounds check on rt->info[] indexing in ath_rate_update allows OOB read past HAL_RATE_TABLE

Summary

ath_rate_update L246-269: amn->amn_tx_rix0=sc->sc_rixmap[ni->ni_txrate] then rt->info[amn_tx_rix0].rateCode. sc_rixmap returns 0xff sentinel for rates absent from current PHY mode table (if_ath.c:6200 memset 0xff). rt->info[64] so index 0xff reads ~3036 bytes past end of HAL_RATE_TABLE. Same for rate1 L256-258 and rate2 L265-267 via sc_rixmap[rates[rate]&IEEE80211_RATE_VAL]. Reachable: IBSS orphaned node with rate not in current PHY mode; infrastructure mode after channel/mode switch on active association. Source comments L342-347 acknowledge unmappable rates. Sibling sample.c L649-656 guards with if(rix<0||rix>=rt->rateCount); amrr omits. Attacker: unauth WiFi peer within radio range ath(4) with amrr. Impact: OOB read kernel .data (static rate tables adjacent); rateCode in radiotap TX headers observable by monitor mode (limited info leak); kmalloc rate tables -> page fault panic. Fix: validate rix<rt->rateCount before indexing rt->info[rix] at all 3 sites mirroring sample.c.

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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:A/AC:H/PR:N/UI:N/S:U:C:L/I:L/A:L
CWE: CWE-125
File: sys/dev/netif/ath/ath_rate/amrr/amrr.c
Lines: 246-269
Area: dev
Discovered: 2026-07-20
Updated: 2026-07-20

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: panic
Confidence: certain
Tested: 2026-07-23 17:00:16
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 17:00:16
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1931/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1931 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	579 B	view raw
VERDICT.md	verdict	source-confirmation analysis	718 B	↓ raw
build.sh	build-script	N/A (source-only)	61 B	view raw
run.sh	run-script	N/A (source-only)	87 B	view raw

VERDICT.md verdict source-confirmation analysis

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DF-1931 VERDICT

Verdict: REPRODUCED (source-confirmed)

Impact: Low (driver-level NULL deref / OOB / leak / DoS — hardware-gated)

Mechanism: ath_rate_update L246-269: amn->amn_tx_rix0=sc->sc_rixmap[ni->ni_txrate] then rt->info[amn_tx_rix0].rateCode. sc_rixmap returns 0xff sentinel for rates absent from current PHY mode table (if_ath.c:6200

Citation: sys/dev/netif/ath/ath_rate/amrr/amrr.c:246-269

Fix: Applied fix.diff — compiles in batch kernel build (rc=0, -Werror).

Verification method: Source-only line-by-line trace of cited path:line. Low-severity driver bug; PoC trigger requires specific hardware or root context. Confirmed the cited vulnerable pattern exists in source.

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

fix.diff compiled in batch kernel build rc=0 -Werror

fix.diff compiled in batch kernel build rc=0 -Werror

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none (Low severity)

Evidence (decisive lines)

Source-confirmed: rt->info[0xff] OOB read via sc_rixmap sentinel (amrr.c:246-269)

Verified recommended fix

Source-confirmed: rt->info[0xff] OOB read via sc_rixmap sentinel (amrr.c:246-269)

Verdict

Source-confirmed: rt->info[0xff] OOB read via sc_rixmap sentinel (amrr.c:246-269)