Summary

smu7_powertune.c:1120/1122 cac_table = table_info->cac_dtp_table (V1) or dyn_state.cac_dtp_table (legacy) NO NULL check. Deref at 1142 (PowerContainment branch), 1215 usTDP, 1217 usConfigurableTDP. Parser only populates when usPowerTuneTableOffset!=0 (process_pptables_v1_0.c:804, processpptables.c:1277-1298). check_powerplay_tables never validates offset. PHM_PlatformCaps_PowerContainment default in amdgpu_pp_feature_mask=0xfffd3fff. SMU7 ASICs (Tahiti through Polaris/VegaM) larger HW base than DF-1550 (Vega10 only). Trigger: crafted VBIOS omitting PowerTune table at attach. Fix: NULL guard before deref + parser-level rejection.

PoC verification

Evidence pack

findings/poc/DF-1610 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	476 B	view raw
VERDICT.md	verdict	source-confirmation analysis	1.1 KB	↓ raw
build.sh	build-script	N/A (source-only)	65 B	view raw
run.sh	run-script	N/A (source-only)	89 B	view raw

VERDICT.md verdict source-confirmation analysis

↓ download raw

DF-1610 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: smu7_powertune.c:1120/1122 cac_table = table_info->cac_dtp_table (V1) or dyn_state.cac_dtp_table (legacy) NO NULL check. Deref at 1142 (PowerContainment branch), 1215 usTDP, 1217 usConfigurableTDP. Pa

Citation: sys/dev/drm/amd/powerplay/hwmgr/smu7_powertune.c:1120-1217

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 status (batch validation)

Applied with the 36 sibling fix.diffs of this batch in findings/poc/_batch41/all_fixes.patch; single in-guest make -j6 nativekernel KERNCONF=X86_64_GENERIC completed RC=0 with zero errors under -Werror (full log: findings/poc/_batch41/fix_build8.log). Behavior A/B intentionally skipped for this Info-tier item.

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: cac_dtp_table NULL deref when VBIOS omits offset (smu7_powertune.c:1120-1217)

Verified recommended fix

Source-confirmed: cac_dtp_table NULL deref when VBIOS omits offset (smu7_powertune.c:1120-1217)

Verdict