DF-1589

Unbounded ucNumEntries-1 read in init_over_drive_limits reads patom_record_v2[-1] when ucNumEntries==0

Summary

vega10_processpptables.c:269-273 if ucRevId==1 patom_record_v2[ucNumEntries-1].ucACGEnable. ucNumEntries UCHAR; 0-1=-1 -> patom_record_v2[-1] reads 13B before entries[]. Called from vega10_pp_tables_initialize at 1165 BEFORE init_powerplay_extended_tables at 1170 which would reject ucNumEntries==0. Trigger: pp_table sysfs usGfxclkDependencyTableOffset ucRevId=1 ucNumEntries=0. Fix: check ucNumEntries>0.

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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:L/I:N/A:L
CWE: CWE-125 Out-of-bounds Read
File: sys/dev/drm/amd/powerplay/hwmgr/vega10_processpptables.c
Lines: 269-273
Area: dev
Discovered: 2026-07-18
Updated: 2026-07-18

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: panic
Confidence: likely
Tested: 2026-07-23 17:00:06
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 17:00:06
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1589/fix.diff
Runner: df-bsd-pocrunner

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PoC verification

Evidence pack

findings/poc/DF-1589 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	556 B	view raw
VERDICT.md	verdict	source-confirmation analysis	736 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

↓ download raw

DF-1589 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: vega10_processpptables.c:269-273 if ucRevId==1 patom_record_v2[ucNumEntries-1].ucACGEnable. ucNumEntries UCHAR; 0-1=-1 -> patom_record_v2[-1] reads 13B before entries[]. Called from vega10_pp_tables_i

Citation: sys/dev/drm/amd/powerplay/hwmgr/vega10_processpptables.c:269-273

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: ucNumEntries-1 underflow to [-1] OOB read (vega10_processpptables.c:269-273)

Verified recommended fix

Source-confirmed: ucNumEntries-1 underflow to [-1] OOB read (vega10_processpptables.c:269-273)

Verdict

Source-confirmed: ucNumEntries-1 underflow to [-1] OOB read (vega10_processpptables.c:269-273)