{
 "finding_id": "DF-3084",
 "status": "reproduced",
 "reproduced": 1,
 "impact": "panic",
 "confidence": "certain",
 "verdict": "Exact predicted reproduction: ext2 image crafted on the host (mke2fs + debugfs sif <dir> size 0x80000000), mounted read-write in the guest, then an UNPRIVILEGED touch(1) inside the oversized directory panics the stock INVARIANTS kernel: \"panic: ext2_write: uio->uio_offset < 0\" with the trace ext2_write <- ext2_direnter <- ext2_makeinode <- vop_old_create. The doff_t (int32_t, ext2_inode.h:53) truncation of the directory size makes the search loop skip silently (0 < INT32_MIN false), the CREATE path sets dp->i_offset = (int32)0x80000000 = negative, and ext2_add_first_entry passes it to VOP_WRITE hitting the KASSERT at ext2_vnops.c:1980. Production kernels return EFBIG via the maxfilesize check instead. Unpriv-user trigger on a root-mounted crafted image: local DoS.",
 "exploit_chain": "crafted dir i_size 0x80000000 -> ext2_lookup_ino search skipped (endsearch negative) -> CREATE notfound path dp->i_offset=INT32_MIN -> ext2_add_first_entry auio.uio_offset negative -> VOP_WRITE -> KASSERT(uio_offset >= 0) panic",
 "evidence": "VERDICT.md + run.log + panic.txt + fix.diff (A/B: fixed kernel #0 Sun Oct 25 06:10:12 UTC 2026)",
 "kernel_refs": [
  "sys/vfs/ext2fs/ext2_lookup.c:424",
  "sys/vfs/ext2fs/ext2_lookup.c:496",
  "sys/vfs/ext2fs/ext2_vnops.c:1980",
  "sys/vfs/ext2fs/inode.h:53"
 ],
 "poc_changes": "none",
 "attempts": 1,
 "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": 30,
 "guest_dirty": 0,
 "build_cmd": "",
 "run_cmd": "see README.md",
 "code_hash": null,
 "notes": "fix_status: fixed - A/B validated: same crafted image + unpriv touch on the fix kernel returns clean EINVAL (touch: /mnt/e84/d/newfile: Invalid argument), no panic (baseline panic.txt vs fixed-run log)",
 "recommended_fix": "fix.diff rejects directory sizes that would truncate negative through doff_t at the notfound/create path; A/B validated on the fixed kernel."
}