⬢ DragonFlyBSD Kernel Audit
DF-4552 / verdict.json
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{
  "finding_id": "DF-4552",
  "status": "not_reproduced",
  "reproduced": 0,
  "impact": "none",
  "confidence": "certain",
  "verdict": "Source-level defect is certain (identical unwind asymmetry to 11 accepted family instances DF-4156..DF-4550): sv_attach publishes the 0666 /dev/mixerN at mixer_init (vibes.c:789) and four later goto-fail paths (815-821, 837-840, 856-859, 872-875) release all bus resources without mixer_uninit, leaving a world-RW mixer whose devinfo (sc) drives bus_space I/O on rman-released ports; sc is also leaked on every fail path and on the early ENXIO at 746-749. Not reproduced on the audit guest because no S3 SonicVibes PCI device exists there: probe built and run as root and unprivileged user, /dev/mixer0 absent (ENOENT), default /dev/mixer clone returns EBADF with zero registered units.",
  "exploit_chain": "",
  "evidence": "run.log sections =B..=I= (pciconf has no 5333 device; mixer_probe ENOENT/EBADF as both root and unprivileged user); VERDICT.md table of the four failure paths; mixer.c:730-733 make_dev 0666; sound.c:1205 mixer_uninit only reachable via pcm_unregister",
  "kernel_refs": [
    "sys/dev/sound/pci/vibes.c:789",
    "sys/dev/sound/pci/vibes.c:815",
    "sys/dev/sound/pci/vibes.c:837",
    "sys/dev/sound/pci/vibes.c:856",
    "sys/dev/sound/pci/vibes.c:872",
    "sys/dev/sound/pci/vibes.c:888",
    "sys/dev/sound/pcm/mixer.c:730",
    "sys/dev/sound/pcm/sound.c:1205"
  ],
  "poc_changes": "authored from scratch this pass (no seed; finding filed this pass)",
  "attempts": 1,
  "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64",
  "runtime_sec": 45,
  "guest_dirty": 0,
  "build_cmd": "cc -O -o /tmp/mixer_probe /tmp/mixer_probe.c (on guest)",
  "run_cmd": "/tmp/mixer_probe /dev/mixer0 ; /tmp/mixer_probe /dev/mixer (root and unprivileged)",
  "code_hash": "50c3f49468b1630aeb1c4ebe798313103cb75a30bd2aac4eee00883c5119f84d",
  "notes": "Incidental: second snd_vibes unload cycle without an intervening /dev/sndstat open panicked the guest in sndstat_sysuninit — that is known finding DF-4116 (already verified reproduced/panic); consistent corroboration, not re-filed. Guest reset with-src after that panic.",
  "recommended_fix": "On every failure path after mixer_init call mixer_uninit(dev) before releasing bus resources, and kfree(sc) on all fail paths (see fix.diff)",
  "fix_status": "not_testable",
  "fix_baseline_reproduced": 0,
  "fix_patched_reproduced": 0,
  "fix_verdict": "Fix not validated on hardware: guest has no SonicVibes device, so neither baseline nor patched behavior is observable; fix.diff is source-reviewed and git-apply-verified only",
  "fix_evidence": "fix.diff"
}