{
  "finding_id": "DF-4029",
  "status": "not_reproduced",
  "reproduced": 0,
  "impact": "none",
  "confidence": "certain",
  "verdict": "r600_packet3_check SET_RESOURCE validates 7-dword resource slots (count%7, reads at i*7) but writes the relocated VALID_BUFFER base at i*8 (r600_cs.c:2010-2012) \u2014 an evergreen copy-paste. Writes land in later slots already-validated words and in trailing reloc-NOP words, so the executed (base,size) pairing diverges from the validated pairing: slot j can execute with base from BO_i while its size was validated against a much larger BO_j -> GPU vertex fetch past small BOs (cross-process disclosure). resource_index_sim (run on the guest, run.log) proves read/write index tables and that mandatory trailing reloc NOPs keep writes inside the IB (past-IB hypothesis explicitly killed). Hardware-gated: no radeon GPU on the audit guest.",
  "exploit_chain": "Unpriv CS with 6 VALID_BUFFER resources mixing a 4 KiB and a 64 MiB BO; executed base/size pairing break -> vertex fetcher reads past the 4 KiB BO into neighboring GPU memory -> sampled/rendered back to attacker BO.",
  "evidence": "VERDICT.md (full path:line trace); run.log (guest trigger run + arithmetic simulation proving the validator math line-exact); build.log (clean guest build); env.txt (guest has no radeon GPU \u2014 hardware-gated); fix.diff (proposed fix, NOT applied to sys/)",
  "kernel_refs": [
    "sys/dev/drm/radeon/r600_cs.c:1941-1953",
    "sys/dev/drm/radeon/r600_cs.c:2000-2013"
  ],
  "poc_changes": "Trigger written from scratch for this pack (raw ioctl, no libdrm, self-contained struct defs); arithmetic sims written to verify each wrap/desync claim line-exact; past-IB hypothesis for DF-4029 explicitly tested and killed by resource_index_sim.",
  "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": "./build.sh (guest: cc -O2 -Wall)",
  "run_cmd": "./run.sh",
  "code_hash": "da0d9a886161bddfef7392d94a40d9e170e476914de693e08ebd3f3c693fc288",
  "notes": "Hardware-gated: the audit QEMU guest exposes no radeon DRM device (/dev/dri absent, QEMU virtio display only \u2014 env.txt), so the run-time chain cannot be exercised; classification is not_reproduced at run-time with certain source-level confidence. All findings verified present in upstream Linux master too (cve_match candidates: equivalent).",
  "recommended_fix": "Use (i*7) in the two write lines (see fix.diff).",
  "fix_status": "not_testable",
  "fix_baseline_reproduced": 0,
  "fix_patched_reproduced": 0,
  "fix_verdict": "fix.diff authored against the read-only sys/ tree after source verification; baseline and patched runs require r600/rv770 hardware which the audit guest lacks, so fix validation is not testable here.",
  "fix_evidence": "fix.diff in this pack"
}