{
 "finding_id": "DF-2856",
 "status": "reproduced",
 "reproduced": 1,
 "impact": "leak",
 "confidence": "certain",
 "verdict": "Mechanically reproduced via the harness on the stock guest with a private rman: reserve a whole chunk (0..63) for owner A, rman_set_virtual(r1, 0xdeadbeef), release; reserve the SAME whole chunk for owner B - rman_get_virtual(res2) returns 0xdeadbeef: the takeover path (subr_rman.c:257-263) ORs flags and sets r_dev without resetting r_virtual/r_bustag/r_bushandle/r_rid, so the new owner reads the PREVIOUS owners mapping pointer/bus handle through the public accessors (cross-driver data hygiene leak of kernel pointers). int_rman_release also only clears RF_ALLOCATED (:592 region) so a stale RF_SHAREABLE persists on free fragments. On the fix kernel the takeover clears all four fields and rman_get_virtual(res2) returns NULL.",
 "exploit_chain": "whole-chunk reuse -> previous owner r_virtual/r_bushandle readable by new driver (kernel pointer disclosure)",
 "evidence": "harness.log T6: res2 virtual=0xdeadbeef; fix kernel T6: NULL",
 "kernel_refs": [
  "sys/kern/subr_rman.c:257",
  "sys/kern/subr_rman.c:263",
  "sys/kern/subr_rman.c:592"
 ],
 "poc_changes": "rman_reserve_resource(rm, start, end, count, flags, dev) argument order; rman_manage_region required after rman_init",
 "attempts": 2,
 "guest_uname": "DragonFly dfbsd 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": "cd /root/h41 && make",
 "run_cmd": "kldload ./h41.ko; sysctl -w debug.h41.cmd=6",
 "code_hash": "85d6e241caa2a7fb1fb44b80c7736a4e83c36d29314b0c96ce91769bc9bdf839",
 "notes": "Kernel-internal caller-contract hygiene; bus_space types are integers on this platform (0, not NULL)",
 "recommended_fix": "Clear r_virtual/r_bustag/r_bushandle/r_rid at whole-chunk takeover and drop RF_SHAREABLE at release",
 "fix_status": "fixed",
 "fix_baseline_reproduced": 1,
 "fix_patched_reproduced": 0,
 "fix_kernel_uname": "DragonFly dfbsd 6.5-DEVELOPMENT #1: Mon Oct 26 01:57:23 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64 (h41 fix kernel, all 41 hardening fixes applied)",
 "fix_verdict": "A/B: baseline 0xdeadbeef stale pointer; fix kernel NULL (fields cleared at takeover; RF_SHAREABLE cleared at release)."
}