Summary

revive_block L196-197 unlockrange(sd->plexno,lock) lives INSIDE else branch that runs only when read completed WITHOUT B_ERROR. If bp->b_flags&B_ERROR (L170 data-block read failure or parityrebuild pbp B_ERROR) control takes if branch sets error skips else so lock acquired at L155 lockrange or parityrebuild L418 *lockp=lockrange is never released. Leaked lock permanently blocks all future I/O on that stripe — every subsequent access tsleep(vrlock) forever vinumlock.c:167. Root starts revive + underlying drive EIO; any unpriv user reads affected offset -> permanent uninterruptible hang. Repeat 256 stripes exhausts PLEX_LOCKS=256 -> full plex deadlock. Fix: move unlockrange out of else block run unconditionally before buffer free.

PoC verification

Evidence pack

findings/poc/DF-1887 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	437 B	view raw
VERDICT.md	verdict	source-confirmation analysis	1.0 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-1887 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: revive_block L196-197 unlockrange(sd->plexno,lock) lives INSIDE else branch that runs only when read completed WITHOUT B_ERROR. If bp->b_flags&B_ERROR (L170 data-block read failure or parityrebuild pb

Citation: sys/dev/raid/vinum/vinumrevive.c:137-220

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: unlockrange skipped on B_ERROR path — permanent I/O lock (vinumrevive.c:196-197)

Verified recommended fix

Source-confirmed: unlockrange skipped on B_ERROR path — permanent I/O lock (vinumrevive.c:196-197)

Verdict