#!/usr/bin/env python3
"""Inspect a Windows kernel driver (.sys): confirm native subsystem and flag kernel primitives.

Parses the PE optional header for the native subsystem and scans strings for kernel imports,
IRP/IOCTL dispatch, arbitrary read/write primitives, and callback registration. Reads bytes
statically; never loads the driver.
"""
from __future__ import annotations

import argparse
import json
import re
import struct
import sys
from pathlib import Path

ASCII_RE = re.compile(rb"[\x20-\x7e]{4,}")

KERNEL_IMPORTS = ["ntoskrnl.exe", "hal.dll", "ndis.sys", "fltmgr.sys", "wdfldr.sys",
                  "storport.sys"]
DISPATCH = ["iocreatedevice", "iocreatesymboliclink", "iodeletedevice", "irp_mj_device_control",
            "iocreatedevicesecure", "wdfdevicecreate"]
RW_PRIMITIVES = ["mmmapiospace", "zwmapviewofsection", "mmcopymemory", "mmmapiospaceex",
                 "zwopensection", "halgetbusdatabyoffset", "mmgetphysicaladdress"]
CALLBACKS = ["pssetcreateprocessnotifyroutine", "pssetloadimagenotifyroutine",
             "obregistercallbacks", "cmregistercallback", "pssetcreatethreadnotifyroutine"]


def _subsystem(data: bytes) -> int | None:
    if data[:2] != b"MZ":
        return None
    e_lfanew = struct.unpack_from("<I", data, 0x3c)[0]
    if data[e_lfanew:e_lfanew + 4] != b"PE\x00\x00":
        return None
    return struct.unpack_from("<H", data, e_lfanew + 24 + 68)[0]


def _strings(data: bytes) -> str:
    return "\n".join(m.decode("latin-1", "ignore") for m in ASCII_RE.findall(data)).lower()


def inspect(path: str) -> dict:
    data = Path(path).read_bytes()
    subsystem = _subsystem(data)
    blob = _strings(data)
    is_driver = subsystem == 1 or any(k in blob for k in KERNEL_IMPORTS)
    capabilities = []
    rw = sorted({p for p in RW_PRIMITIVES if p in blob})
    cbs = sorted({c for c in CALLBACKS if c in blob})
    if rw:
        capabilities.append("arbitrary_memory_access")
    if cbs:
        capabilities.append("kernel_callback_registration")
    if any(d in blob for d in DISPATCH):
        capabilities.append("ioctl_dispatch")
    return {
        "is_kernel_driver": is_driver,
        "pe_subsystem": subsystem,
        "kernel_imports": sorted({k for k in KERNEL_IMPORTS if k in blob}),
        "dispatch_indicators": sorted({d for d in DISPATCH if d in blob}),
        "read_write_primitives": rw,
        "callback_registration": cbs,
        "capabilities": capabilities,
        "byovd_risk": bool(rw),
    }


def main(argv: list[str] | None = None) -> int:
    parser = argparse.ArgumentParser(description="Inspect a Windows kernel driver")
    sub = parser.add_subparsers(dest="cmd", required=True)
    p = sub.add_parser("inspect")
    p.add_argument("file")
    args = parser.parse_args(argv)
    print(json.dumps(inspect(args.file), indent=2))
    return 0


if __name__ == "__main__":
    sys.exit(main())