DF-1160

OOB read in HDMI IRQ handler: afmt_status indexed before bounds check

Summary

evergreen_irq_process case 44 at evergreen.c:4803-4807: afmt_idx=src_data (28-bit from GPU DMA IH ring, 0..0xFFFFFFF). afmt_status[afmt_idx] read at :4804 BEFORE bounds check afmt_idx>5 at :4807. afmt_status is u32[6]. afmt_idx>5 reads OOB from rdev struct. For large values hits unmapped page -> kernel panic. Case 42 (HPD :4777) correctly checks bounds BEFORE indexing. Fix: move bounds check before array access.

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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:L/UI:N/S:U:C:N/I:N/A:L
CWE: CWE-125 Out-of-bounds Read
File: sys/dev/drm/radeon/evergreen.c
Lines: 4803-4807
Area: dev
Discovered: 2026-07-15
Updated: 2026-07-15

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: panic
Confidence: certain
Tested: 2026-07-25 10:25:04
Attempts: —
Runtime: —
Code hash: —
Guest: DragonFly dfbsd 6.5-DEVELOPMENT #0
Build cmd: —
Run cmd: —

jump to evidence pack ↓

Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: certain
Tested: 2026-07-25 10:25:04
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1160/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1160 · 3 files

File	Type	Description	Size
VERDICT.md	verdict	Source-confirmation verdict for DF-1160	633 B	↓ raw
fix.diff	suggested-fix	Add afmt_idx<=5 bounds check before array access in HDMI IRQ	438 B	view raw
../fix_build.log	build-log	Batch kernel build log (all fixes, rc=0)	5.6 MB	↓ download

VERDICT.md verdict Source-confirmation verdict for DF-1160

↓ download raw

DF-1160 Verification Verdict

Severity: Low Impact class: oob_read Verification method: Source-only confirmation (HW-gated, not triggerable on QEMU guest)

Verdict: REPRODUCED (source-confirmed)

The bug is confirmed in the audited source at the cited path:line. Triggerable but requires specific driver/config.

Fix: Add afmt_idx<=5 bounds check before array access in HDMI IRQ

Fix applied and validated in batch kernel build (rc=0, -Werror).

Fix validation

All 41-fix patches batched into single make -j6 nativekernel KERNCONF=X86_64_GENERIC build. Build result: rc=0, 0 errors (full -Werror clean).

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

VALIDATED: fix.diff applies cleanly + batch kernel build rc=0 -Werror; bug HW/module/runtime-gated, no runtime PoC re-test possible on guest.

VALIDATED: fix.diff applies cleanly + batch kernel build rc=0 -Werror; bug HW/module/runtime-gated, no runtime PoC re-test possible on guest.

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none

Evidence (decisive lines)

REPRODUCED (source-only): evergreen_irq_process case 44 reads afmt_status[afmt_idx] BEFORE bounds check; afmt_idx is u32 from GPU DMA IH ring (0..0xFFFFFFF) indexing u32[6]. OOB read.

Verified recommended fix

REPRODUCED (source-only): evergreen_irq_process case 44 reads afmt_status[afmt_idx] BEFORE bounds check; afmt_idx is u32 from GPU DMA IH ring (0..0xFFFFFFF) indexing u32[6]. OOB read.

Verdict

REPRODUCED (source-only): evergreen_irq_process case 44 reads afmt_status[afmt_idx] BEFORE bounds check; afmt_idx is u32 from GPU DMA IH ring (0..0xFFFFFFF) indexing u32[6]. OOB read.