Off-by-one in get_powerplay_table_entry_v1_0 allows OOB read of one state entry
Summary
process_pptables_v1_0.c:1310 PP_ASSERT_WITH_CODE(entry_index <= state_arrays->ucNumEntries) uses <= instead of <. entry_index==ucNumEntries passes -> entries[ucNumEntries] one past end -> 20 bytes OOB BIOS image read. Latent: sole caller pp_psm.c:75-89 iterates i<table_entries. Fix: change <= to <.
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-1577 Β· 4 files| File | Type | Description | Size | |
|---|---|---|---|---|
| fix.diff | suggested-fix | git-apply-able fix for the cited bug | 700 B | view raw |
| VERDICT.md | verdict | source-confirmation analysis | 1.1 KB | β 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 |
DF-1577 VERDICT
Verdict: REPRODUCED (source-confirmed)
Impact: Low (driver-level NULL deref / OOB / leak / DoS β hardware-gated)
Mechanism: process_pptables_v1_0.c:1310 PP_ASSERT_WITH_CODE(entry_index <= state_arrays->ucNumEntries) uses <= instead of <. entry_index==ucNumEntries passes -> entries[ucNumEntries] one past end -> 20 bytes OOB
Citation: sys/dev/drm/amd/powerplay/hwmgr/process_pptables_v1_0.c:1310-1315
Fix: Applied fix.diff β 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
fixedfix.diff compiled in batch kernel build rc=0 -Werror
fix.diff compiled in batch kernel build rc=0 -Werror
Confirmed kernel references
β
Detail
Exploit chain
none (Low severity)
Evidence (decisive lines)
Source-confirmed: entry_index<=ucNumEntries off-by-one OOB read (process_pptables_v1_0.c:1310)
Verified recommended fix
Source-confirmed: entry_index<=ucNumEntries off-by-one OOB read (process_pptables_v1_0.c:1310)
Verdict
Source-confirmed: entry_index<=ucNumEntries off-by-one OOB read (process_pptables_v1_0.c:1310)
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