DF-1886

parityrebuild divides by plex->stripesize and plex->subdisks with no zero guard: div0 panic

Summary

parityrebuild L367 stripe=pstripe/plex->stripesize L368 psd=plex->subdisks-1-stripe%plex->subdisks both integer divisions. Sole caller parityops L265 checks only isparity(plex) (organization>=plex_raid4) and plex->state never validates stripesize>0 or subdisks>0. Plex with organization=raid4/5 but stripesize=0 (or subdisks=0) reachable via inconsistent config/corrupted disk label/interrupted reconfig. L274 size=imin(DEFAULT_REVIVE_BLOCKSIZE,stripesize<<DEV_BSHIFT)=0 proceeds. Same divisor pattern in revive_block L99/109/113/116/118/120 (%stripesize) for striped/raid4/5 revive. Root-only VINUM_PARITYOP. Fix: validate stripesize>0&&subdisks>0 in parityops before calling parityrebuild.

Discussion (0)

No comments yet.

Severity: Low
Status: new
Bucket: Base system — drivers
Confidence: likely
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-369
File: sys/dev/raid/vinum/vinumrevive.c
Lines: 116-382
Area: dev
Discovered: 2026-07-20
Updated: 2026-07-20

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: panic
Confidence: likely
Tested: 2026-07-23 17:00:13
Attempts: —
Runtime: —
Code hash: —
Guest: DragonFly dfbsd 6.5-DEVELOPMENT #0
Build cmd: —
Run cmd: —

jump to evidence pack ↓

Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: likely
Tested: 2026-07-23 17:00:13
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1886/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1886 · 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	712 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-1886 VERDICT

Verdict: REPRODUCED (source-confirmed)

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

Mechanism: parityrebuild L367 stripe=pstripe/plex->stripesize L368 psd=plex->subdisks-1-stripe%plex->subdisks both integer divisions. Sole caller parityops L265 checks only isparity(plex) (organization>=plex_rai

Citation: sys/dev/raid/vinum/vinumrevive.c:116-382

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: div-by-zero when stripesize=0 or subdisks=0 (vinumrevive.c:367-368)

Verified recommended fix

Source-confirmed: div-by-zero when stripesize=0 or subdisks=0 (vinumrevive.c:367-368)

Verdict

Source-confirmed: div-by-zero when stripesize=0 or subdisks=0 (vinumrevive.c:367-368)