{
 "finding_id": "DF-3837",
 "status": "inconclusive",
 "reproduced": 0,
 "impact": "none",
 "confidence": "certain",
 "verdict": "Source-level certain, runtime inconclusive: the audit QEMU guest is virtio-only (no /dev/dri, hw.drm absent), so the CS ioctl cannot be exercised. The VM-path IB parser hand-rolls packet walking with no fit check (unlike radeon_cs_packet_parse at radeon_cs.c:768) and evergreen_vm_packet3_check reads ib[pkt->idx+1] unconditionally plus ib[idx+3..idx+5] for COND_WRITE/COPY_DW/CP_DMA without any pkt->count validation, so a TYPE3 header as the last IB dword forces reads up to 5 dwords past ib->length_dw inside the kernel-mapped IB pool; the OOB dword is echoed to the log by DRM_ERROR(\"Invalid register 0x%x in CS\"). PoC compiles clean on the guest and fails at open(/dev/dri/card0) with ENOENT, as documented in run.log.",
 "exploit_chain": "",
 "evidence": "README.md (what to look at), VERDICT.md (line-by-line trace), trigger.c/mkbadfw.c, build.log (clean guest compile, gcc 8.3), run.log (honest ENOENT / generator RUN_OK), env.txt (guest has no DRI, no iwi NIC), fix.diff",
 "kernel_refs": [
  "sys/dev/drm/radeon/evergreen_cs.c:3519",
  "sys/dev/drm/radeon/evergreen_cs.c:3350",
  "sys/dev/drm/radeon/evergreen_cs.c:3407",
  "sys/dev/drm/radeon/evergreen_cs.c:3414",
  "sys/dev/drm/radeon/evergreen_cs.c:3435",
  "sys/dev/drm/radeon/evergreen_cs.c:3341",
  "sys/dev/drm/radeon/radeon_cs.c:546",
  "sys/dev/drm/radeon/radeon_asic.c:1619"
 ],
 "poc_changes": "PoC authored fresh for this finding (cross-file family seed): raw DRM ioctl ABI (cmd low byte 0x66 dispatches RADEON_CS on DF drm_ioctl.c:809), chunk structs and packet encodings verified against sys/dev/drm/include/uapi/drm/radeon_drm.h; iwi mkbadfw.c emits the v3 combined-image header per if_iwireg.h:161-166.",
 "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": 30,
 "guest_dirty": 0,
 "build_cmd": "cc -O2 -o trigger trigger.c",
 "run_cmd": "./trigger /dev/dri/card0",
 "code_hash": "f80029395c94dfbce2acaad30987559c2df8d11e5fb04e5cae218e4d1534df9f",
 "notes": "Hardware-gated: audit QEMU guest is virtio-only (no /dev/dri, hw.drm absent, no iwi PCI NIC) - runtime verification impossible in this environment; classification per orchestrator enum (no not_testable/skipped). Guest was NOT dirtied; no kernel rebuild performed (nothing reproduced to validate a fix against).",
 "recommended_fix": "Add idx+1<length_dw guard, pkt.idx+pkt.count+2<=length_dw fit check before dispatch, and exact pkt->count requirements for COND_WRITE/COPY_DW/CP_DMA in the VM parser.",
 "fix_status": "not_applicable",
 "fix_baseline_reproduced": 0,
 "fix_patched_reproduced": 0,
 "fix_verdict": "Fix validation impossible on this guest: the vulnerable device (AMD radeon CS / Intel 2200BG) does not exist, so neither baseline nor patched kernel can exercise the path. fix.diff authored against the read-only sys/ tree, never applied.",
 "fix_evidence": "fix.diff in this pack; structurally mirrors the bounds checks the same driver family already enforces elsewhere (radeon_cs_packet_parse fit check; iwn ring-index masking)."
}