DF-2063 — PoC evidence pack

Finding: Unchecked adv_attach() return leaks resources, leaves IRQ active on half-init softc Class: Improper error handling / resource leak (CWE-755) | Impact ceiling: none | Confidence: certain

Status

SOURCE-CONFIRMED. The defect is verified real by line-by-line tracing of the audited sys/ tree, but it is HW/module-gated: the audit guest lacks the required hardware/module (AdvanSys ASC1200A/ASC3000 PCI SCSI HBA (vendor 0x10CD) or VFIO-assigned crafted endpoint that probes but fails adv_start_chip), so it cannot be triggered at runtime here. See VERDICT.md for the full mechanism and citations.

How to reproduce (on a guest that HAS the hardware)

1. Ensure the gating precondition is met: AdvanSys ASC1200A/ASC3000 PCI SCSI HBA (vendor 0x10CD) or VFIO-assigned crafted endpoint that probes but fails adv_start_chip.
2. Apply fix.diff to confirm the cited path changes; before the fix the cited code path exhibits the behaviour described in VERDICT.md.
3. The original finding markdown describes the runtime trigger.

Build validation (Phase 8)

fix.diff applies cleanly to pristine source. All nine findings' fixes were built together; see VERDICT.md "Phase 8" and fix_build.log:

make -j6 nativekernel KERNCONF=X86_64_GENERIC   # rc=0, -Werror, 0 warnings

Files

• VERDICT.md — full narrative, mechanism, citations, fix-build result
• fix.diff — standalone git apply-able fix (authored post-verification)
• fix_build.log — full combined-fix kernel build output (rc=0, -Werror)
• env.txt — guest environment for this verification
• manifest.json — machine-readable catalog

DF-2063 — VERDICT

Verdict: REPRODUCED (source-confirmed; HW/module-gated — not runtime-triggerable on this guest) Class: Improper error handling / resource leak (CWE-755) Impact ceiling: none Confidence: certain

Reproduction status

This finding is HW/module-gated and could not be triggered at runtime on the audit guest. The guest has no Atheros NIC, no AdvanSys HBA, no Intel i915 GPU, no AMD Southern-Islands GPU, no LSI MegaRAID controller, and no loaded dm device (only vtnet0). The PoC therefore cannot reach the vulnerable path at runtime here. The bug is instead confirmed by line-by-line source tracing against the audited sys/ tree (master DEV, the same commit the kernel was built from) — the defect is real and deterministic given the hardware/module, which is the standard bar for HW-gated driver findings.

Mechanism (source-confirmed)

adv_pci_attach() calls adv_attach(adv) at adv_pci.c:296 and unconditionally return 0 at :297 without checking the return value. adv_attach() (advansys.c:1284-1414) can fail at 7 points (DMA tag, sense buffer alloc, adv_start_chip read-back, cam_sim_alloc, xpt_bus_register, xpt_create_path). On failure the device is reported attached but half-initialized, leaking DMA tags / ccb_infos / sense buffers, and the interrupt handler registered at adv_pci.c:290 (bus_setup_intr) stays active against a softc whose sim/path may be NULL. The sibling adw_pci.c:300-303 correctly checks the return and calls adw_free.

Gating precondition: AdvanSys ASC1200A/ASC3000 PCI SCSI HBA (vendor 0x10CD) or VFIO-assigned crafted endpoint that probes but fails adv_start_chip

Exploit chain

Not applicable — this finding is HW/module-gated on the audit guest (no triggering hardware/module present), so no userspace-driven escalation chain can be exercised here. Per AGENT.md Phase 6 the valid hard blocker that applies is "vulnerable code path is reachable only on hardware/module absent from this guest." The realistic impact ceiling for the bug itself is none as documented above (panic for the corruption-class bugs on default GENERIC with INVARIANTS ON; dos for the I/O-wedge/stall bugs; none/graceful-fallback for the validation-bypass and pure missing-check / resource-leak findings).

Fix (authored, git-apply-able)

Capture error = adv_attach(adv) in adv_pci_attach(); on non-zero return, bus_teardown_intr() + release the IRQ and IOPORT resources + adv_free() + propagate the error, mirroring adw_pci.c.

The standalone diff is fix.diff in this directory. It applies cleanly to the pristine audited source (git apply --check verified).

Phase 8 — combined fix-build validation

All nine findings' fixes were applied together to a single in-guest source tree and built with make -j6 nativekernel KERNCONF=X86_64_GENERIC. The DragonFly kernel compile invokes cc ... -Werror on every translation unit, so this is a true -Werror build.

• Result: === NK_DONE rc=0 === (full log: fix_build.log)
• Compiler errors in changed files: 0
• Compiler warnings (entire tree): 0
• Patched kernel.stripped sha256: 6086a989213ef7be890180f60edc0fd9827bf60efbc3ed8c969724746e250df6
• Baseline (unpatched) kernel: DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026

Because the PoC is HW/module-gated, the fix could not be runtime A/B tested on this guest (no way to trigger the bad behaviour on either the baseline or the patched kernel). The fix is therefore classified fix_status = not_testable (compile-validated + source-traced to close the cited path), which is the honest result for HW-gated findings.

Kernel references (verified during this trace)

• sys/dev/disk/advansys/adv_pci.c:296
• sys/dev/disk/advansys/adv_pci.c:297
• sys/dev/disk/advansys/advansys.c:1337
• sys/dev/disk/advansys/adw_pci.c:300