DF-1420

OOB read of vddc_dependency_on_sclk in smu8_read_sensor GFX_SCLK (index vs table->count)

Summary

smu8_read_sensor at smu8_hwmgr.c:1706: if(sclk_index<NUM_SCLK_LEVELS=8) sclk=table->entries[sclk_index]. table->count may be <8. index in [count,8) -> OOB heap read returned to userspace as GFX_SCLK via sensor ioctl. Fix: check sclk_index<table->count.

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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:H/PR:L/UI:N/S:U:C:H/I:N/A:N
CWE: CWE-125 Out-of-bounds Read
File: sys/dev/drm/amd/powerplay/hwmgr/smu8_hwmgr.c
Lines: 1688-1708
Area: dev
Discovered: 2026-07-17
Updated: 2026-07-17

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: none
Confidence: likely
Tested: 2026-07-23 15:26:20
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: likely
Tested: 2026-07-23 15:26:20
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1420/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1420 · 2 files

File	Type	Description	Size
VERDICT.md	verdict	verification verdict	798 B	↓ raw
fix.diff	suggested-fix	git-apply-able fix	856 B	view raw

VERDICT.md verdict verification verdict

↓ download raw

DF-1420 - Verification Verdict

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

Finding

OOB read of vddc_dependency_on_sclk in smu8_read_sensor GFX_SCLK (index vs table->count)

Source Location

sys/dev/drm/amd/powerplay/hwmgr/smu8_hwmgr.c:1688-1708

Verdict

Source-confirmed: OOB read of vddc_dependency_on_sclk in smu8_read_sensor GFX_SCLK (inde. 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

smu8_read_sensor at smu8_hwmgr.c:1706: if(sclk_indexentries[sclk_index]. table->count may be <8. index in [count,8) -> OOB heap read returned to userspace as GFX_SCLK via sensor ioctl. Fix: check sclk_indexcount.

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: smu8_read_sensor GFX_SCLK reads table->entries[sclk_index] with sclk_index from SMC register, not bounded to table->count. Added min() bound. HW-gated.

Verified recommended fix

Source-confirmed: smu8_read_sensor GFX_SCLK reads table->entries[sclk_index] with sclk_index from SMC register, not bounded to table->count. Added min() bound. HW-gated.

Verdict

Source-confirmed: smu8_read_sensor GFX_SCLK reads table->entries[sclk_index] with sclk_index from SMC register, not bounded to table->count. Added min() bound. HW-gated.