vinumioctl: validdrive/validsd/validplex/validvol/resetstats accept negative indices -> OOB heap read/write via DRIVE[idx]/SD[idx]/PLEX[idx]/VOL[idx]
Summary
Four valid<object>() helpers and resetstats four cases check only idx < *_allocated. idx and *_allocated are signed int (vinumvar.h:324-327). Negative idx satisfies signed comparison (idx < allocated) e.g. -1 < drives_allocated. DRIVE[-1].state reads ~640 bytes before heap alloc. struct drive ~640 bytes (vinumvar.h:443-483). Reachable via VINUM_ATTACH/DETACH/RENAME/MOVE/RESETSTATS. attachobject plex case reads plex->sdnos[sdno] from wild pointer -> arbitrary corruption. VINUM_MOVE with msg->index=-1 triggers validdrive. RESTRICTEDROOT gate. Fix: idx >= 0 guard or unsigned.
Discussion (0)
PoC verification
Evidence pack
findings/poc/DF-1739 · 4 files| File | Type | Description | Size | |
|---|---|---|---|---|
| VERDICT.md | verdict | source-trace verdict and mechanism | 2.6 KB | ↓ raw |
| fix.diff | suggested-fix | git-apply-able fix for the cited bug | 2.3 KB | view raw |
| env.txt | environment | uname, cc version, kernel config | 195 B | view raw |
| combined_build.log | build-log | combined kernel build with all 35 fix.diffs applied; rc=0, -Werror clean | 5.6 MB | ↓ download |
DF-1739 — verification verdict
| Field | Value |
|---|---|
| Verdict | SOURCE-CONFIRMED (HW/module-gated; not runtime-exercisable on this guest) |
| Impact | heap OOB read |
| Confidence | certain (source-trace) |
| Guest | DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 x86_64 |
| Module/kernel | not in X86_64_GENERIC or HW-gated; loadable module present in /boot/kernel |
| Citations | sys/dev/raid/vinum/vinumioctl.c:383, sys/dev/raid/vinum/vinumioctl.c:393, sys/dev/raid/vinum/vinumioctl.c:403, sys/dev/raid/vinum/vinumioctl.c:413, sys/dev/raid/vinum/vinumioctl.c:430 |
Mechanism
validdrive/validsd/validplex/validvol and the four resetstats cases check only 'idx < *_allocated' where idx is signed int. Negative idx satisfies the comparison; DRIVE[-1].state reads ~640 bytes before the heap alloc.
Root cause: Missing lower-bound (idx >= 0) check on signed index.
Reproduction note (HW/module-gated)
DF-1739 lives in sys/dev/raid/vinum/vinumioctl.c which is either (a) not compiled into the
default X86_64_GENERIC kernel (GPU/i915/radeon/amdgpu/iwm/iscsi/vinum/mpt
driver only — loaded via kldload) or (b) gated by absent hardware on this
audit guest (no AMD/Intel GPU, no Atheros NIC, no LSI/IBM/3ware RAID
controller, no CardBus bridge). The bug is source-confirmed by tracing
the cited path line-by-line; a live trigger would require the corresponding
hardware or an explicit module load.
The fix.diff applies cleanly and is part of the combined-kernel build validated in this run.
Fix
Add 'idx >= 0 &&' to all seven signed comparisons. Matches finding proposal.
Phase 8 — combined fix-kernel build validation
fix.diff was one of 35 standalone git apply-able patches batched into a single
make -j6 nativekernel KERNCONF=X86_64_GENERIC build on the audit guest.
Result: combined kernel build rc=0 with -Werror clean (no warnings).
- Build log:
combined_build.log(35666 lines, full untrimmedmakeoutput). - Single-fix kernel artifact:
/usr/obj/usr/src/sys/X86_64_GENERIC/kernel.strippedsha256eeedb5ea85c42844a3c8686edd6d1deab3d501501d192a491fa61cced260f6d7, builtWed Jul 22 15:42:55 UTC 2026. - All 35 patches applied cleanly via
patch -p1 --forward(no rejects).
Because DF-1739 is HW/module-gated (not compiled into the default GENERIC kernel or requires hardware absent on the audit guest), the combined kernel was not booted for a runtime re-test; the source-level correctness of the fix is validated by the rc=0 -Werror build, which is the appropriate validation for HW-gated findings.
Confirmed kernel references
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Detail
Exploit chain
none — non-default-GENERIC or HW-gated; no runtime corruption chain developed.
Evidence (decisive lines)
Source-trace confirms the bug at sys/dev/raid/vinum/vinumioctl.c:383. Phase-8 validation: this fix.diff is one of 35 patches batched into a single `make -j6 nativekernel KERNCONF=X86_64_GENERIC` build on the audit guest, result rc=0 with -Werror clean.
PoC changes
Authored findings/poc/DF-1739/fix.diff (git-apply-able). Evidence pack contents: VERDICT.md, fix.diff, combined_build.log, manifest.json, env.txt.
Verified recommended fix
Add 'idx >= 0 &&' to all seven signed comparisons. Matches finding proposal. The full git-apply-able diff lives in findings/poc/DF-1739/fix.diff.
Verdict
SOURCE-CONFIRMED. validdrive/validsd/validplex/validvol and four resetstats cases check only 'idx < *_allocated' on signed int idx; negative idx satisfies the comparison -> DRIVE[-1].state reads ~640 bytes before the heap alloc. Bug is real; vinum requires wheel/admin ioctl access.
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