Summary

vinumrequest.c:491 sd=NULL for compiler quiet. 492 for(sdno=0;sdno<plex->subdisks;sdno++) zero iterations if subdisks==0. 556 if(diskend>sd->sectors+sd->plexoffset) derefs NULL->sectors -> panic. Plex org concat no subdisks: vinum create plex p0 org concat (no sd lines). vinumopen accepts plex_init (vinum.c:419-427 only rejects unallocated/referenced). Any I/O against empty concat plex panics. Fix: guard plex->subdisks==0 at top of plex_concat case -> REQUEST_DOWN.

PoC verification

Evidence pack

findings/poc/DF-1647 · 4 files

File	Type	Description	Size
fix.diff	suggested-fix	git-apply-able fix for the cited bug	496 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-1647 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: vinumrequest.c:491 sd=NULL for compiler quiet. 492 for(sdno=0;sdnosubdisks;sdno++) zero iterations if subdisks==0. 556 if(diskend>sd->sectors+sd->plexoffset) derefs NULL->sectors -> panic. Plex

Citation: sys/dev/raid/vinum/vinumrequest.c:491-556

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: NULL sd deref when concat plex has 0 subdisks (vinumrequest.c:491-556)

Verified recommended fix

Source-confirmed: NULL sd deref when concat plex has 0 subdisks (vinumrequest.c:491-556)

Verdict