me_cleaner.py

#!/usr/bin/python

# me_cleaner - Tool for partial deblobbing of Intel ME/TXE firmware images
# Copyright (C) 2016-2018 Nicola Corna <nicola@corna.info>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#

from __future__ import division, print_function

import argparse
import binascii
import hashlib
import itertools
import shutil
import sys
import re
from struct import pack, unpack


min_ftpr_offset = 0x400
spared_blocks = 4
unremovable_modules = ("ROMP", "BUP")
unremovable_modules_gen3 = ("rbe", "kernel", "syslib", "bup")
unremovable_partitions = ("FTPR",)

pubkeys_md5 = {
    "8431285d43b0f2a2f520d7cab3d34178": ("ME",  ("2.0.x.x", "2.1.x.x",
                                                 "2.2.x.x")),
    "4c00dd06c28119b5c1e5bb8eb6f30596": ("ME",  ("2.5.x.x", "2.6.x.x")),
    "9c24077a7f7490967855e9c4c16c6b9e": ("ME",  ("3.x.x.x",)),
    "bf41464be736f5520d80c67f6789020e": ("ME",  ("4.x.x.x",)),
    "5c7169b7e7065323fb7b3b5657b4d57a": ("ME",  ("5.x.x.x",)),
    "763e59ebe235e45a197a5b1a378dfa04": ("ME",  ("6.x.x.x",)),
    "3a98c847d609c253e145bd36512629cb": ("ME",  ("6.0.50.x",)),
    "0903fc25b0f6bed8c4ed724aca02124c": ("ME",  ("7.x.x.x", "8.x.x.x")),
    "2011ae6df87c40fba09e3f20459b1ce0": ("ME",  ("9.0.x.x", "9.1.x.x")),
    "e8427c5691cf8b56bc5cdd82746957ed": ("ME",  ("9.5.x.x", "10.x.x.x")),
    "986a78e481f185f7d54e4af06eb413f6": ("ME",  ("11.x.x.x",)),
    "3efc26920b4bee901b624771c742887b": ("ME",  ("12.x.x.x",)),
    "bda0b6bb8ca0bf0cac55ac4c4d55e0f2": ("TXE", ("1.x.x.x",)),
    "b726a2ab9cd59d4e62fe2bead7cf6997": ("TXE", ("1.x.x.x",)),
    "0633d7f951a3e7968ae7460861be9cfb": ("TXE", ("2.x.x.x",)),
    "1d0a36e9f5881540d8e4b382c6612ed8": ("TXE", ("3.x.x.x",)),
    "be900fef868f770d266b1fc67e887e69": ("SPS", ("2.x.x.x",)),
    "4622e3f2cb212a89c90a4de3336d88d2": ("SPS", ("3.x.x.x",)),
    "31ef3d950eac99d18e187375c0764ca4": ("SPS", ("4.x.x.x",))
}


class OutOfRegionException(Exception):
    pass


class RegionFile:
    def __init__(self, f, region_start, region_end):
        self.f = f
        self.region_start = region_start
        self.region_end = region_end

    def readall(self):
        currentpos = self.f.tell()
        self.f.seek(self.region_start)
        toret = self.f.read(self.region_end - self.region_start)
        self.f.seek(currentpos)
        return toret

    def read(self, n):
        if f.tell() + n <= self.region_end:
            return self.f.read(n)
        else:
            raise OutOfRegionException()

    def readinto(self, b):
        if f.tell() + len(b) <= self.region_end:
            return self.f.readinto(b)
        else:
            raise OutOfRegionException()

    def seek(self, offset):
        if self.region_start + offset <= self.region_end:
            return self.f.seek(self.region_start + offset)
        else:
            raise OutOfRegionException()

    def write_to(self, offset, data):
        if self.region_start + offset + len(data) <= self.region_end:
            self.f.seek(self.region_start + offset)
            return self.f.write(data)
        else:
            raise OutOfRegionException()

    def fill_range(self, start, end, fill):
        if self.region_start + end <= self.region_end:
            if start < end:
                block = fill * 4096
                self.f.seek(self.region_start + start)
                self.f.writelines(itertools.repeat(block,
                                                   (end - start) // 4096))
                self.f.write(block[:(end - start) % 4096])
        else:
            raise OutOfRegionException()

    def fill_all(self, fill):
        self.fill_range(0, self.region_end - self.region_start, fill)

    def move_range(self, offset_from, size, offset_to, fill):
        if self.region_start + offset_from + size <= self.region_end and \
           self.region_start + offset_to + size <= self.region_end:
            for i in range(0, size, 4096):
                self.f.seek(self.region_start + offset_from + i, 0)
                block = self.f.read(min(size - i, 4096))
                self.f.seek(self.region_start + offset_from + i, 0)
                self.f.write(fill * len(block))
                self.f.seek(self.region_start + offset_to + i, 0)
                self.f.write(block)
        else:
            raise OutOfRegionException()

    def save(self, filename, size):
        if self.region_start + size <= self.region_end:
            self.f.seek(self.region_start)
            copyf = open(filename, "w+b")
            for i in range(0, size, 4096):
                copyf.write(self.f.read(min(size - i, 4096)))
            return copyf
        else:
            raise OutOfRegionException()


def get_chunks_offsets(llut):
    chunk_count = unpack("<I", llut[0x04:0x08])[0]
    huffman_stream_end = sum(unpack("<II", llut[0x10:0x18]))
    nonzero_offsets = [huffman_stream_end]
    offsets = []

    for i in range(0, chunk_count):
        chunk = llut[0x40 + i * 4:0x44 + i * 4]
        offset = 0

        if chunk[3] != 0x80:
            offset = unpack("<I", chunk[0:3] + b"\x00")[0]

        offsets.append([offset, 0])
        if offset != 0:
            nonzero_offsets.append(offset)

    nonzero_offsets.sort()

    for i in offsets:
        if i[0] != 0:
            i[1] = nonzero_offsets[nonzero_offsets.index(i[0]) + 1]

    return offsets


def remove_modules(f, mod_headers, ftpr_offset, me_end):
    comp_str = ("uncomp.", "Huffman", "LZMA")
    unremovable_huff_chunks = []
    chunks_offsets = []
    base = 0
    chunk_size = 0
    end_addr = 0

    for mod_header in mod_headers:
        name = mod_header[0x04:0x14].rstrip(b"\x00").decode("ascii")
        offset = unpack("<I", mod_header[0x38:0x3C])[0] + ftpr_offset
        size = unpack("<I", mod_header[0x40:0x44])[0]
        flags = unpack("<I", mod_header[0x50:0x54])[0]
        comp_type = (flags >> 4) & 7

        print(" {:<16} ({:<7}, ".format(name, comp_str[comp_type]), end="")

        if comp_type == 0x00 or comp_type == 0x02:
            print("0x{:06x} - 0x{:06x}       ): "
                  .format(offset, offset + size), end="")

            if name in unremovable_modules:
                end_addr = max(end_addr, offset + size)
                print("NOT removed, essential")
            else:
                end = min(offset + size, me_end)
                f.fill_range(offset, end, b"\xff")
                print("removed")

        elif comp_type == 0x01:
            if not chunks_offsets:
                f.seek(offset)
                llut = f.read(4)
                if llut == b"LLUT":
                    llut += f.read(0x3c)

                    chunk_count = unpack("<I", llut[0x4:0x8])[0]
                    base = unpack("<I", llut[0x8:0xc])[0] + 0x10000000
                    chunk_size = unpack("<I", llut[0x30:0x34])[0]

                    llut += f.read(chunk_count * 4)
                    chunks_offsets = get_chunks_offsets(llut)
                else:
                    sys.exit("Huffman modules found, but LLUT is not present")

            module_base = unpack("<I", mod_header[0x34:0x38])[0]
            module_size = unpack("<I", mod_header[0x3c:0x40])[0]
            first_chunk_num = (module_base - base) // chunk_size
            last_chunk_num = first_chunk_num + module_size // chunk_size
            huff_size = 0

            for chunk in chunks_offsets[first_chunk_num:last_chunk_num + 1]:
                huff_size += chunk[1] - chunk[0]

            print("fragmented data, {:<9}): "
                  .format("~" + str(int(round(huff_size / 1024))) + " KiB"),
                  end="")

            if name in unremovable_modules:
                print("NOT removed, essential")

                unremovable_huff_chunks += \
                    [x for x in chunks_offsets[first_chunk_num:
                     last_chunk_num + 1] if x[0] != 0]
            else:
                print("removed")

        else:
            print("0x{:06x} - 0x{:06x}): unknown compression, skipping"
                  .format(offset, offset + size), end="")

    if chunks_offsets:
        removable_huff_chunks = []

        for chunk in chunks_offsets:
            if all(not(unremovable_chk[0] <= chunk[0] < unremovable_chk[1] or
                       unremovable_chk[0] < chunk[1] <= unremovable_chk[1])
                   for unremovable_chk in unremovable_huff_chunks):
                removable_huff_chunks.append(chunk)

        for removable_chunk in removable_huff_chunks:
            if removable_chunk[1] > removable_chunk[0]:
                end = min(removable_chunk[1], me_end)
                f.fill_range(removable_chunk[0], end, b"\xff")

        end_addr = max(end_addr,
                       max(unremovable_huff_chunks, key=lambda x: x[1])[1])

    return end_addr


def check_partition_signature(f, offset):
    f.seek(offset)
    header = f.read(0x80)
    modulus = int(binascii.hexlify(f.read(0x100)[::-1]), 16)
    public_exponent = unpack("<I", f.read(4))[0]
    signature = int(binascii.hexlify(f.read(0x100)[::-1]), 16)

    header_len = unpack("<I", header[0x4:0x8])[0] * 4
    manifest_len = unpack("<I", header[0x18:0x1c])[0] * 4
    f.seek(offset + header_len)

    sha256 = hashlib.sha256()
    sha256.update(header)
    sha256.update(f.read(manifest_len - header_len))

    decrypted_sig = pow(signature, public_exponent, modulus)

    return "{:#x}".format(decrypted_sig).endswith(sha256.hexdigest())   # FIXME


def print_check_partition_signature(f, offset):
    if check_partition_signature(f, offset):
        print("VALID")
    else:
        print("INVALID!!")
        sys.exit("The FTPR partition signature is not valid. Is the input "
                 "ME/TXE image valid?")


def relocate_partition(f, me_end, partition_header_offset,
                       new_offset, mod_headers):

    f.seek(partition_header_offset)
    name = f.read(4).rstrip(b"\x00").decode("ascii")
    f.seek(partition_header_offset + 0x8)
    old_offset, partition_size = unpack("<II", f.read(0x8))

    llut_start = 0
    for mod_header in mod_headers:
        if (unpack("<I", mod_header[0x50:0x54])[0] >> 4) & 7 == 0x01:
            llut_start = unpack("<I", mod_header[0x38:0x3C])[0] + old_offset
            break

    if mod_headers and llut_start != 0:
        # Bytes 0x9:0xb of the LLUT (bytes 0x1:0x3 of the AddrBase) are added
        # to the SpiBase (bytes 0xc:0x10 of the LLUT) to compute the final
        # start of the LLUT. Since AddrBase is not modifiable, we can act only
        # on SpiBase and here we compute the minimum allowed new_offset.
        f.seek(llut_start + 0x9)
        lut_start_corr = unpack("<H", f.read(2))[0]
        new_offset = max(new_offset,
                         lut_start_corr - llut_start - 0x40 + old_offset)
        new_offset = ((new_offset + 0x1f) // 0x20) * 0x20

    offset_diff = new_offset - old_offset
    print("Relocating {} from {:#x} - {:#x} to {:#x} - {:#x}..."
          .format(name, old_offset, old_offset + partition_size,
                  new_offset, new_offset + partition_size))

    print(" Adjusting FPT entry...")
    f.write_to(partition_header_offset + 0x8,
               pack("<I", new_offset))

    if mod_headers:
        if llut_start != 0:
            f.seek(llut_start)
            if f.read(4) == b"LLUT":
                print(" Adjusting LUT start offset...")
                lut_offset = llut_start + offset_diff + 0x40 - lut_start_corr
                f.write_to(llut_start + 0x0c, pack("<I", lut_offset))

                print(" Adjusting Huffman start offset...")
                f.seek(llut_start + 0x14)
                old_huff_offset = unpack("<I", f.read(4))[0]
                f.write_to(llut_start + 0x14,
                           pack("<I", old_huff_offset + offset_diff))

                print(" Adjusting chunks offsets...")
                f.seek(llut_start + 0x4)
                chunk_count = unpack("<I", f.read(4))[0]
                f.seek(llut_start + 0x40)
                chunks = bytearray(chunk_count * 4)
                f.readinto(chunks)
                for i in range(0, chunk_count * 4, 4):
                    if chunks[i + 3] != 0x80:
                        chunks[i:i + 3] = \
                            pack("<I", unpack("<I", chunks[i:i + 3] +
                                 b"\x00")[0] + offset_diff)[0:3]
                f.write_to(llut_start + 0x40, chunks)
            else:
                sys.exit("Huffman modules present but no LLUT found!")
        else:
            print(" No Huffman modules found")

    print(" Moving data...")
    partition_size = min(partition_size, me_end - old_offset)
    f.move_range(old_offset, partition_size, new_offset, b"\xff")

    return new_offset


def check_and_remove_modules(f, me_end, offset, min_offset,
                             relocate, keep_modules):

    f.seek(offset + 0x20)
    num_modules = unpack("<I", f.read(4))[0]
    f.seek(offset + 0x290)
    data = f.read(0x84)

    mod_header_size = 0
    if data[0x0:0x4] == b"$MME":
        if data[0x60:0x64] == b"$MME" or num_modules == 1:
            mod_header_size = 0x60
        elif data[0x80:0x84] == b"$MME":
            mod_header_size = 0x80

    if mod_header_size != 0:
        f.seek(offset + 0x290)
        data = f.read(mod_header_size * num_modules)
        mod_headers = [data[i * mod_header_size:(i + 1) * mod_header_size]
                       for i in range(0, num_modules)]

        if all(hdr.startswith(b"$MME") for hdr in mod_headers):
            if args.keep_modules:
                end_addr = offset + ftpr_length
            else:
                end_addr = remove_modules(f, mod_headers, offset, me_end)

            if args.relocate:
                new_offset = relocate_partition(f, me_end, 0x30, min_offset,
                                                mod_headers)
                end_addr += new_offset - offset
                offset = new_offset

            return end_addr, offset

        else:
            print("Found less modules than expected in the FTPR "
                  "partition; skipping modules removal")
    else:
        print("Can't find the module header size; skipping "
              "modules removal")

    return -1, offset


def check_and_remove_modules_gen3(f, me_end, partition_offset,
                                  partition_length, min_offset, relocate,
                                  keep_modules):

    comp_str = ("LZMA/uncomp.", "Huffman")

    if keep_modules:
        end_data = partition_offset + partition_length
    else:
        end_data = 0

        f.seek(partition_offset + 0x4)
        module_count = unpack("<I", f.read(4))[0]

        modules = []
        modules.append(("end", partition_length, 0))

        f.seek(partition_offset + 0x10)
        for i in range(0, module_count):
            data = f.read(0x18)
            name = data[0x0:0xc].rstrip(b"\x00").decode("ascii")
            offset_block = unpack("<I", data[0xc:0x10])[0]
            offset = offset_block & 0x01ffffff
            comp_type = (offset_block & 0x02000000) >> 25

            modules.append((name, offset, comp_type))

        modules.sort(key=lambda x: x[1])

        for i in range(0, module_count):
            name = modules[i][0]
            offset = partition_offset + modules[i][1]
            end = partition_offset + modules[i + 1][1]
            removed = False

            if name.endswith(".man") or name.endswith(".met"):
                compression = "uncompressed"
            else:
                compression = comp_str[modules[i][2]]

            print(" {:<12} ({:<12}, 0x{:06x} - 0x{:06x}): "
                  .format(name, compression, offset, end), end="")

            if name.endswith(".man"):
                print("NOT removed, partition manif.")
            elif name.endswith(".met"):
                print("NOT removed, module metadata")
            elif any(name.startswith(m) for m in unremovable_modules_gen3):
                print("NOT removed, essential")
            else:
                removed = True
                f.fill_range(offset, min(end, me_end), b"\xff")
                print("removed")

            if not removed:
                end_data = max(end_data, end)

    if relocate:
        new_offset = relocate_partition(f, me_end, 0x30, min_offset, [])
        end_data += new_offset - partition_offset
        partition_offset = new_offset

    return end_data, partition_offset


def check_mn2_tag(f, offset, gen):
    f.seek(offset + 0x1c)
    tag = f.read(4)
    expected_tag = b"$MAN" if gen == 1 else b"$MN2"
    if tag != expected_tag:
        sys.exit("Wrong FTPR manifest tag ({}), this image may be corrupted"
                 .format(tag))


def flreg_to_start_end(flreg):
    return (flreg & 0x7fff) << 12, (flreg >> 4 & 0x7fff000 | 0xfff) + 1


def start_end_to_flreg(start, end):
    return (start & 0x7fff000) >> 12 | ((end - 1) & 0x7fff000) << 4


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Tool to remove as much code "
                                     "as possible from Intel ME/TXE firmware "
                                     "images")
    softdis = parser.add_mutually_exclusive_group()
    bw_list = parser.add_mutually_exclusive_group()

    parser.add_argument("-v", "--version", action="version",
                        version="%(prog)s 1.2")

    parser.add_argument("file", help="ME/TXE image or full dump")
    parser.add_argument("-O", "--output", metavar='output_file', help="save "
                        "the modified image in a separate file, instead of "
                        "modifying the original file")
    softdis.add_argument("-S", "--soft-disable", help="in addition to the "
                         "usual operations on the ME/TXE firmware, set the "
                         "MeAltDisable bit or the HAP bit to ask Intel ME/TXE "
                         "to disable itself after the hardware initialization "
                         "(requires a full dump)", action="store_true")
    softdis.add_argument("-s", "--soft-disable-only", help="instead of the "
                         "usual operations on the ME/TXE firmware, just set "
                         "the MeAltDisable bit or the HAP bit to ask Intel "
                         "ME/TXE to disable itself after the hardware "
                         "initialization (requires a full dump)",
                         action="store_true")
    parser.add_argument("-r", "--relocate", help="relocate the FTPR partition "
                        "to the top of the ME region to save even more space",
                        action="store_true")
    parser.add_argument("-t", "--truncate", help="truncate the empty part of "
                        "the firmware (requires a separated ME/TXE image or "
                        "--extract-me)", action="store_true")
    parser.add_argument("-k", "--keep-modules", help="don't remove the FTPR "
                        "modules, even when possible", action="store_true")
    bw_list.add_argument("-w", "--whitelist", metavar="whitelist",
                         help="Comma separated list of additional partitions "
                         "to keep in the final image. This can be used to "
                         "specify the MFS partition for example, which stores "
                         "PCIe and clock settings.")
    bw_list.add_argument("-b", "--blacklist", metavar="blacklist",
                         help="Comma separated list of partitions to remove "
                         "from the image. This option overrides the default "
                         "removal list.")
    parser.add_argument("-d", "--descriptor", help="remove the ME/TXE "
                        "Read/Write permissions to the other regions on the "
                        "flash from the Intel Flash Descriptor (requires a "
                        "full dump)", action="store_true")
    parser.add_argument("-D", "--extract-descriptor",
                        metavar='output_descriptor', help="extract the flash "
                        "descriptor from a full dump; when used with "
                        "--truncate save a descriptor with adjusted regions "
                        "start and end")
    parser.add_argument("-M", "--extract-me", metavar='output_me_image',
                        help="extract the ME firmware from a full dump; when "
                        "used with --truncate save a truncated ME/TXE image")
    parser.add_argument("-c", "--check", help="verify the integrity of the "
                        "fundamental parts of the firmware and exit",
                        action="store_true")

    args = parser.parse_args()

    if args.check and (args.soft_disable_only or args.soft_disable or
       args.relocate or args.descriptor or args.truncate or args.output):
        sys.exit("-c can't be used with -S, -s, -r, -d, -t or -O")

    if args.soft_disable_only and (args.relocate or args.truncate):
        sys.exit("-s can't be used with -r or -t")

    if (args.whitelist or args.blacklist) and args.relocate:
        sys.exit("Relocation is not yet supported with custom whitelist or "
                 "blacklist")

    gen = None

    f = open(args.file, "rb" if args.check or args.output else "r+b")
    magic0 = f.read(4)
    f.seek(0x10)
    magic10 = f.read(4)

    if b"$FPT" in {magic0, magic10}:
        print("ME/TXE image detected")

        if args.descriptor or args.extract_descriptor or args.extract_me or \
           args.soft_disable or args.soft_disable_only:
            sys.exit("-d, -D, -M, -S and -s require a full dump")

        f.seek(0, 2)
        me_start = 0
        me_end = f.tell()
        mef = RegionFile(f, me_start, me_end)

    elif b"\x5a\xa5\xf0\x0f" in {magic0, magic10}:
        print("Full image detected")

        f.seek(0x4 if magic0 == b"\x5a\xa5\xf0\x0f" else 0x14)
        flmap0, flmap1, flmap2 = unpack("<III", f.read(0xc))
        frba = flmap0 >> 12 & 0xff0
        fmba = (flmap1 & 0xff) << 4

        # Generation 1
        fisba = flmap1 >> 12 & 0xff0
        fmsba = (flmap2 & 0xff) << 4

        # Generation 2-3
        fpsba = fisba

        f.seek(frba)
        flreg = unpack("<III", f.read(12))

        fd_start, fd_end = flreg_to_start_end(flreg[0])
        bios_start, bios_end = flreg_to_start_end(flreg[1])
        me_start, me_end = flreg_to_start_end(flreg[2])

        if me_start >= me_end:
            print("The ME region in this image has already been disabled")
        else:
            mef = RegionFile(f, me_start, me_end)

        if magic0 == b"\x5a\xa5\xf0\x0f":
            gen = 1

    else:
        sys.exit("Unknown image")

    if me_start < me_end:
        medata = mef.readall()
        fpt_matches = list((re.compile(br'\x24\x46\x50\x54.\x00\x00\x00', re.DOTALL)).finditer(medata))
        if (len(fpt_matches) == 0):
            sys.exit("$FPT not found")

        if (len(fpt_matches) > 1):
            sys.exit("more than one $FPT found")

        for fpt_match in fpt_matches:
            fpt_offset = fpt_match.span()[0]

    if gen == 1:
        end_addr = 0
    else:
        end_addr = me_end

    if me_start < me_end:
        print("Found FPT header at {:#x}".format(mef.region_start + fpt_offset))

        mef.seek(fpt_offset + 0x4)
        entries = unpack("<I", mef.read(4))[0]
        print("Found {} partition(s)".format(entries))

        mef.seek(fpt_offset + 0x20)
        partitions = mef.read(entries * 0x20)

        ftpr_header = b""

        for i in range(entries):
            if partitions[i * 0x20:(i * 0x20) + 4] in {b"CODE", b"FTPR"}:
                ftpr_header = partitions[i * 0x20:(i + 1) * 0x20]
                break

        if ftpr_header == b"":
            # We might be dealing with IFWI firmware, look for $CPD with FPTR
            ftpr_matches = list((re.compile(br'\x24\x43\x50\x44........\x46\x54\x50\x52', re.DOTALL)).finditer(medata))

            if (len(ftpr_matches) == 1):
                ftpr_offset = ftpr_matches[0].span()[0]
                ftpr_length = 0 # As long as we only do soft-disable on IFWI, should be okay
            else:
                sys.exit("FTPR header not found, this image doesn't seem to be "
                        "valid")
        else:
            if ftpr_header[0x0:0x4] == b"CODE":
                gen = 1

            ftpr_offset, ftpr_length = unpack("<II", ftpr_header[0x08:0x10])

        print("Found FTPR header: FTPR partition spans from {:#x} to {:#x}"
              .format(ftpr_offset, ftpr_offset + ftpr_length))

        mef.seek(ftpr_offset)
        if mef.read(4) == b"$CPD":
            gen = 3
            num_entries = unpack("<I", mef.read(4))[0]

            mef.seek(ftpr_offset + 0x10)
            ftpr_mn2_offset = -1

            for i in range(0, num_entries):
                data = mef.read(0x18)
                name = data[0x0:0xc].rstrip(b"\x00").decode("ascii")
                offset = unpack("<I", data[0xc:0xf] + b"\x00")[0]

                if name == "FTPR.man":
                    ftpr_mn2_offset = offset
                    break

            if ftpr_mn2_offset >= 0:
                check_mn2_tag(mef, ftpr_offset + ftpr_mn2_offset, gen)
                print("Found FTPR manifest at {:#x}"
                      .format(ftpr_offset + ftpr_mn2_offset))
            else:
                sys.exit("Can't find the manifest of the FTPR partition")

        else:
            check_mn2_tag(mef, ftpr_offset, gen)
            ftpr_mn2_offset = 0
            if not gen:
                gen = 2

        mef.seek(ftpr_offset + ftpr_mn2_offset + 0x24)
        version = unpack("<HHHH", mef.read(0x08))

        if version[0] == 12:
            gen = 4

        print("ME/TXE firmware version {} (generation {})"
              .format('.'.join(str(i) for i in version), gen))

        mef.seek(ftpr_offset + ftpr_mn2_offset + 0x80)
        pubkey_md5 = hashlib.md5(mef.read(0x104)).hexdigest()

        if pubkey_md5 in pubkeys_md5:
            variant, pubkey_versions = pubkeys_md5[pubkey_md5]
            print("Public key match: Intel {}, firmware versions {}"
                  .format(variant, ", ".join(pubkey_versions)))
        else:
            if version[0] >= 6:
                variant = "ME"
            else:
                variant = "TXE"
            print("WARNING Unknown public key {}\n"
                  "        Assuming Intel {}\n"
                  "        Please report this warning to the project's "
                  "maintainer!"
                  .format(pubkey_md5, variant))

    if not args.check and args.output:
        f.close()
        shutil.copy(args.file, args.output)
        f = open(args.output, "r+b")

    if me_start < me_end:
        mef = RegionFile(f, me_start, me_end)

    if me_start > 0:
        fdf = RegionFile(f, fd_start, fd_end)

        if gen == 1:
            for (ba, name) in ((fisba, "ICHSTRP0"), (fmsba, "MCHSTRP0")):
                fdf.seek(ba)
                strp = unpack("<I", fdf.read(4))[0]
                print("The meDisable bit in " + name + " is ", end="")
                if strp & 1:
                    print("SET")
                elif args.check:
                    print("NOT SET")
                else:
                    print("NOT SET, setting it now...")
                    fdf.write_to(ba, pack("<I", strp | 1))
        elif gen == 2:
            fdf.seek(fpsba + 0x28)
            pchstrp10 = unpack("<I", fdf.read(4))[0]
            print("The AltMeDisable bit is " +
                  ("SET" if pchstrp10 & 1 << 7 else "NOT SET"))
        elif gen == 4:
            fdf.seek(fpsba + 0x80)
            pchstrp32 = unpack("<I", fdf.read(4))[0]
            print("The HAP bit is " +
                  ("SET" if pchstrp32 & 1 << 16 else "NOT SET"))
        else:
            fdf.seek(fpsba)
            pchstrp0 = unpack("<I", fdf.read(4))[0]
            print("The HAP bit is " +
                  ("SET" if pchstrp0 & 1 << 16 else "NOT SET"))

        # Generation 1: wipe everything and disable the ME region
        if gen == 1 and me_start < me_end and not args.check:
            print("Disabling the ME region...")
            f.seek(frba + 0x8)
            f.write(pack("<I", 0x1fff))

            print("Wiping the ME region...")
            mef = RegionFile(f, me_start, me_end)
            mef.fill_all("\xff")

    # ME 6 Ignition: wipe everything
    me6_ignition = False
    if gen == 2 and not args.check and not args.soft_disable_only and \
       variant == "ME" and version[0] == 6:
        mef.seek(ftpr_offset + 0x20)
        num_modules = unpack("<I", mef.read(4))[0]
        mef.seek(ftpr_offset + 0x290 + (num_modules + 1) * 0x60)
        data = mef.read(0xc)

        if data[0x0:0x4] == b"$SKU" and data[0x8:0xc] == b"\x00\x00\x00\x00":
            print("ME 6 Ignition firmware detected, removing everything...")
            mef.fill_all(b"\xff")
            me6_ignition = True

    if gen != 1 and not args.check:
        if not args.soft_disable_only and not me6_ignition:
            if gen == 4:
                print("Module removal is not currently supported on IFWI firmware.")
            else:
                print("Reading partitions list...")
                unremovable_part_fpt = b""
                extra_part_end = 0
                whitelist = []
                blacklist = []

                whitelist += unremovable_partitions

                if args.blacklist:
                    blacklist = args.blacklist.split(",")
                elif args.whitelist:
                    whitelist += args.whitelist.split(",")

                for i in range(entries):
                    partition = partitions[i * 0x20:(i + 1) * 0x20]
                    flags = unpack("<I", partition[0x1c:0x20])[0]

                    try:
                        part_name = \
                            partition[0x0:0x4].rstrip(b"\x00").decode("ascii")
                    except UnicodeDecodeError:
                        part_name = "????"

                    part_start, part_length = unpack("<II", partition[0x08:0x10])

                    # ME 6: the last partition has 0xffffffff as size
                    if variant == "ME" and version[0] == 6 and \
                    i == entries - 1 and part_length == 0xffffffff:
                        part_length = me_end - me_start - part_start

                    part_end = part_start + part_length

                    if flags & 0x7f == 2:
                        print(" {:<4} ({:^24}, 0x{:08x} total bytes): nothing to "
                            "remove"
                            .format(part_name, "NVRAM partition, no data",
                                    part_length))
                    elif part_start == 0 or part_length == 0 or part_end > me_end:
                        print(" {:<4} ({:^24}, 0x{:08x} total bytes): nothing to "
                            "remove"
                            .format(part_name, "no data here", part_length))
                    else:
                        print(" {:<4} (0x{:08x} - 0x{:09x}, 0x{:08x} total bytes): "
                            .format(part_name, part_start, part_end, part_length),
                            end="")
                        if part_name in whitelist or (blacklist and
                        part_name not in blacklist):
                            unremovable_part_fpt += partition
                            if part_name != "FTPR":
                                extra_part_end = max(extra_part_end, part_end)
                            print("NOT removed")
                        else:
                            mef.fill_range(part_start, part_end, b"\xff")
                            print("removed")

                print("Removing partition entries in FPT...")
                mef.write_to(0x30, unremovable_part_fpt)
                mef.write_to(0x14,
                            pack("<I", len(unremovable_part_fpt) // 0x20))

                mef.fill_range(0x30 + len(unremovable_part_fpt),
                            0x30 + len(partitions), b"\xff")

                if (not blacklist and "EFFS" not in whitelist) or \
                "EFFS" in blacklist:
                    print("Removing EFFS presence flag...")
                    mef.seek(0x24)
                    flags = unpack("<I", mef.read(4))[0]
                    flags &= ~(0x00000001)
                    mef.write_to(0x24, pack("<I", flags))

                if gen == 3:
                    mef.seek(0x10)
                    header = bytearray(mef.read(0x20))
                    header[0x0b] = 0x00
                else:
                    mef.seek(0)
                    header = bytearray(mef.read(0x30))
                    header[0x1b] = 0x00
                checksum = (0x100 - sum(header) & 0xff) & 0xff

                print("Correcting checksum (0x{:02x})...".format(checksum))
                # The checksum is just the two's complement of the sum of the first
                # 0x30 bytes in ME < 11 or bytes 0x10:0x30 in ME >= 11 (except for
                # 0x1b, the checksum itself). In other words, the sum of those
                # bytes must be always 0x00.
                mef.write_to(0x1b, pack("B", checksum))

                print("Reading FTPR modules list...")
                if gen == 3:
                    end_addr, ftpr_offset = \
                        check_and_remove_modules_gen3(mef, me_end,
                                                    ftpr_offset, ftpr_length,
                                                    min_ftpr_offset,
                                                    args.relocate,
                                                    args.keep_modules)
                else:
                    end_addr, ftpr_offset = \
                        check_and_remove_modules(mef, me_end, ftpr_offset,
                                                min_ftpr_offset, args.relocate,
                                                args.keep_modules)

                if end_addr > 0:
                    end_addr = max(end_addr, extra_part_end)
                    end_addr = (end_addr // 0x1000 + 1) * 0x1000
                    end_addr += spared_blocks * 0x1000

                    print("The ME minimum size should be {0} bytes "
                        "({0:#x} bytes)".format(end_addr))

                    if me_start > 0:
                        print("The ME region can be reduced up to:\n"
                            " {:08x}:{:08x} me"
                            .format(me_start, me_start + end_addr - 1))
                    elif args.truncate:
                        print("Truncating file at {:#x}...".format(end_addr))
                        f.truncate(end_addr)

        if args.soft_disable or args.soft_disable_only:
            if gen == 3:
                print("Setting the HAP bit in PCHSTRP0 to disable Intel ME...")
                pchstrp0 |= (1 << 16)
                fdf.write_to(fpsba, pack("<I", pchstrp0))
            elif gen == 4:
                print("Setting the HAP bit in PCHSTRP32 to disable Intel ME...")
                pchstrp32 |= (1 << 16)
                fdf.write_to(fpsba + 0x80, pack("<I", pchstrp32))
            else:
                print("Setting the AltMeDisable bit in PCHSTRP10 to disable "
                      "Intel ME...")
                pchstrp10 |= (1 << 7)
                fdf.write_to(fpsba + 0x28, pack("<I", pchstrp10))

    if args.descriptor:
        print("Removing ME/TXE R/W access to the other flash regions...")
        if gen == 3:
            flmstr2 = 0x00400500
        else:
            fdf.seek(fmba + 0x4)
            flmstr2 = (unpack("<I", fdf.read(4))[0] | 0x04040000) & 0x0404ffff

        fdf.write_to(fmba + 0x4, pack("<I", flmstr2))

    if args.extract_descriptor:
        if args.truncate:
            print("Extracting the descriptor to \"{}\"..."
                  .format(args.extract_descriptor))
            fdf_copy = fdf.save(args.extract_descriptor, fd_end - fd_start)

            if bios_start == me_end:
                print("Modifying the regions of the extracted descriptor...")
                print(" {:08x}:{:08x} me   --> {:08x}:{:08x} me"
                      .format(me_start, me_end - 1,
                              me_start, me_start + end_addr - 1))
                print(" {:08x}:{:08x} bios --> {:08x}:{:08x} bios"
                      .format(bios_start, bios_end - 1,
                              me_start + end_addr, bios_end - 1))

                flreg1 = start_end_to_flreg(me_start + end_addr, bios_end)
                if gen != 1:
                    flreg2 = start_end_to_flreg(me_start, me_start + end_addr)

                fdf_copy.seek(frba + 0x4)
                fdf_copy.write(pack("<I", flreg1))
                if gen != 1:
                    fdf_copy.write(pack("<I", flreg2))
            else:
                print("\nWARNING:\n"
                      "The start address of the BIOS region (0x{:08x}) isn't "
                      "equal to the end address\nof the ME region (0x{:08x}): "
                      "if you want to recover the space from the ME \nregion "
                      "you have to manually modify the descriptor.\n"
                      .format(bios_start, me_end))
        else:
            print("Extracting the descriptor to \"{}\"..."
                  .format(args.extract_descriptor))
            fdf_copy = fdf.save(args.extract_descriptor, fd_end - fd_start)

        fdf_copy.close()

    if gen != 1:
        if args.extract_me:
            if args.truncate:
                print("Extracting and truncating the ME image to \"{}\"..."
                      .format(args.extract_me))
                mef_copy = mef.save(args.extract_me, end_addr)
            else:
                print("Extracting the ME image to \"{}\"..."
                      .format(args.extract_me))
                mef_copy = mef.save(args.extract_me, me_end - me_start)

            if not me6_ignition:
                print("Checking the FTPR RSA signature of the extracted ME "
                      "image... ", end="")
                print_check_partition_signature(mef_copy,
                                                ftpr_offset + ftpr_mn2_offset)
            mef_copy.close()

        if not me6_ignition:
            print("Checking the FTPR RSA signature... ", end="")
            print_check_partition_signature(mef, ftpr_offset + ftpr_mn2_offset)

    f.close()

    if not args.check:
        print("Done! Good luck!")