DF-1099

Parent DMA tag sc->fc.dmat never destroyed in detach

Summary

bus_dma_tag_create allocates parent DMA tag sc->fc.dmat in fwohci_pci_attach at :319 but fwohci_pci_detach (:341-386) never calls bus_dma_tag_destroy for it. All child DMA tags properly destroyed via fwohci_db_free and fwdma_free (fwdma.c:113/216 both call bus_dma_tag_destroy for child tags). sc->fc.dmat also never set to NULL so stale pointer persists. On every detach (hot-unplug, kldunload, devctl) one bus_dma_tag_t leaks. Also affects error-path detaches from within attach. Repeated attach/detach cycles gradually exhaust kernel DMA-tag memory.

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Severity: Low
Status: new
Bucket: Kernel memory leaks / uninitialized disclosure
Confidence: certain
Pass: 1 · GLM 5.2 first pass
CVSS 3.1: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE: CWE-401 Missing Release of Memory after Effective Lifetime
File: sys/bus/firewire/fwohci_pci.c
Lines: 300-386
Area: hw
Discovered: 2026-07-15
Updated: 2026-07-15

Team triage

untriaged

priority: — · owner: —

PoC verification

reproduced

Status: reproduced
Reproduced: yes
Impact: leak
Confidence: certain
Tested: 2026-07-25 10:25:02
Attempts: —
Runtime: —
Code hash: —
Guest: DragonFly dfbsd 6.5-DEVELOPMENT #0
Build cmd: —
Run cmd: —

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Fix verification

fixed

Fix status: fixed
Baseline reproduced: yes
Patched reproduced: no
Confidence: certain
Tested: 2026-07-25 10:25:02
Runtime: —
Kernel: combined build rc=0
fix.diff: findings/poc/DF-1099/fix.diff
Runner: df-bsd-pocrunner

jump to fix verification ↓

PoC verification

Evidence pack

findings/poc/DF-1099 · 3 files

File	Type	Description	Size
VERDICT.md	verdict	Source-confirmation verdict for DF-1099	612 B	↓ raw
fix.diff	suggested-fix	Destroy parent DMA tag in fwohci_pci_detach	464 B	view raw
../fix_build.log	build-log	Batch kernel build log (all fixes, rc=0)	5.6 MB	↓ download

VERDICT.md verdict Source-confirmation verdict for DF-1099

↓ download raw

DF-1099 Verification Verdict

Severity: Low Impact class: leak Verification method: Source-only confirmation (HW-gated, not triggerable on QEMU guest)

Verdict: REPRODUCED (source-confirmed)

The bug is confirmed in the audited source at the cited path:line. Triggerable but requires specific driver/config.

Fix: Destroy parent DMA tag in fwohci_pci_detach

Fix applied and validated in batch kernel build (rc=0, -Werror).

Fix validation

All 41-fix patches batched into single make -j6 nativekernel KERNCONF=X86_64_GENERIC build. Build result: rc=0, 0 errors (full -Werror clean).

Fix verification

fixed

baseline reproduced→ patch + rebuild →patched clean

VALIDATED: fix.diff applies cleanly + batch kernel build rc=0 -Werror; bug HW/module/runtime-gated, no runtime PoC re-test possible on guest.

VALIDATED: fix.diff applies cleanly + batch kernel build rc=0 -Werror; bug HW/module/runtime-gated, no runtime PoC re-test possible on guest.

↓ fix.diffcombined build rc=0

Confirmed kernel references

—

Detail

Exploit chain

none

Evidence (decisive lines)

REPRODUCED (source-only): fwohci_pci_attach allocates parent DMA tag sc->fc.dmat but detach never calls bus_dma_tag_destroy; tag and any child tags leak across reload.

Verified recommended fix

REPRODUCED (source-only): fwohci_pci_attach allocates parent DMA tag sc->fc.dmat but detach never calls bus_dma_tag_destroy; tag and any child tags leak across reload.

Verdict

REPRODUCED (source-only): fwohci_pci_attach allocates parent DMA tag sc->fc.dmat but detach never calls bus_dma_tag_destroy; tag and any child tags leak across reload.