506 lines
18 KiB
Python
Executable File
506 lines
18 KiB
Python
Executable File
#!/usr/bin/python
|
|
|
|
# me_cleaner - Tool for partial deblobbing of Intel ME/TXE firmware images
|
|
# Copyright (C) 2016, 2017 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.
|
|
#
|
|
|
|
import sys
|
|
import itertools
|
|
import binascii
|
|
import hashlib
|
|
import argparse
|
|
import shutil
|
|
from struct import pack, unpack
|
|
|
|
|
|
min_ftpr_offset = 0x400
|
|
spared_blocks = 4
|
|
unremovable_modules = ("BUP", "ROMP")
|
|
|
|
|
|
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 read(self, n):
|
|
return self.f.read(n)
|
|
|
|
def readinto(self, b):
|
|
return self.f.readinto(b)
|
|
|
|
def seek(self, offset):
|
|
return self.f.seek(offset)
|
|
|
|
def write_to(self, offset, data):
|
|
if offset >= self.region_start and \
|
|
offset + len(data) <= self.region_end:
|
|
self.f.seek(offset)
|
|
return self.f.write(data)
|
|
else:
|
|
raise OutOfRegionException()
|
|
|
|
def fill_range(self, start, end, fill):
|
|
if start >= self.region_start and end <= self.region_end:
|
|
if start < end:
|
|
block = fill * 4096
|
|
self.f.seek(start)
|
|
self.f.writelines(itertools.repeat(block,
|
|
(end - start) // 4096))
|
|
self.f.write(block[:(end - start) % 4096])
|
|
else:
|
|
raise OutOfRegionException()
|
|
|
|
def move_range(self, offset_from, size, offset_to, fill):
|
|
if offset_from >= self.region_start and \
|
|
offset_from + size <= self.region_end and \
|
|
offset_to >= self.region_start and \
|
|
offset_to + size <= self.region_end:
|
|
for i in range(0, size, 4096):
|
|
self.f.seek(offset_from + i, 0)
|
|
block = self.f.read(4096 if size - i >= 4096 else size - i)
|
|
self.f.seek(offset_from + i, 0)
|
|
self.f.write(fill * len(block))
|
|
self.f.seek(offset_to + i, 0)
|
|
self.f.write(block)
|
|
else:
|
|
raise OutOfRegionException()
|
|
|
|
|
|
def get_chunks_offsets(llut, me_start):
|
|
chunk_count = unpack("<I", llut[0x04:0x08])[0]
|
|
huffman_stream_end = sum(unpack("<II", llut[0x10:0x18])) + me_start
|
|
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] + me_start
|
|
|
|
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
|
|
|
|
sys.stdout.write(" {:<16} ({:<7}, ".format(name, comp_str[comp_type]))
|
|
|
|
if comp_type == 0x00 or comp_type == 0x02:
|
|
sys.stdout.write("0x{:06x} - 0x{:06x}): "
|
|
.format(offset, offset + size))
|
|
|
|
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:
|
|
sys.stdout.write("fragmented data ): ")
|
|
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, me_start)
|
|
else:
|
|
sys.exit("Huffman modules found, but LLUT is not present")
|
|
|
|
if name in unremovable_modules:
|
|
print("NOT removed, essential")
|
|
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
|
|
|
|
unremovable_huff_chunks += \
|
|
[x for x in chunks_offsets[first_chunk_num:
|
|
last_chunk_num + 1] if x[0] != 0]
|
|
else:
|
|
print("removed")
|
|
|
|
else:
|
|
sys.stdout.write("0x{:06x} - 0x{:06x}): unknown compression, "
|
|
"skipping".format(offset, offset + size))
|
|
|
|
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 relocate_partition(f, me_start, 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))
|
|
old_offset += me_start
|
|
|
|
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 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 + me_start - llut_start - 0x40 +
|
|
old_offset)
|
|
new_offset = ((new_offset + 0x1f) // 0x20) * 0x20
|
|
|
|
offset_diff = new_offset - old_offset
|
|
print("Relocating {} to {:#x} - {:#x}..."
|
|
.format(name, new_offset, new_offset + partition_size))
|
|
|
|
print(" Adjusting FPT entry...")
|
|
f.write_to(partition_header_offset + 0x8,
|
|
pack("<I", new_offset - me_start))
|
|
|
|
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 - me_start
|
|
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
|
|
|
|
|
|
if __name__ == "__main__":
|
|
parser = argparse.ArgumentParser(description="Tool to remove as much code "
|
|
"as possible from Intel ME/TXE firmwares")
|
|
parser.add_argument("file", help="ME/TXE image or full dump")
|
|
parser.add_argument("-O", "--output", help="save the modified image in a "
|
|
"separate file, instead of modifying the original "
|
|
"file")
|
|
parser.add_argument("-r", "--relocate", help="relocate the FTPR partition "
|
|
"to the top of the ME region", action="store_true")
|
|
parser.add_argument("-k", "--keep-modules", help="don't remove the FTPR "
|
|
"modules, even when possible", action="store_true")
|
|
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("-c", "--check", help="verify the integrity of the "
|
|
"fundamental parts of the firmware and exit",
|
|
action="store_true")
|
|
args = parser.parse_args()
|
|
|
|
f = open(args.file, "rb" if args.check or args.output else "r+b")
|
|
f.seek(0x10)
|
|
magic = f.read(4)
|
|
|
|
if magic == b"$FPT":
|
|
print("ME/TXE image detected")
|
|
me_start = 0
|
|
f.seek(0, 2)
|
|
me_end = f.tell()
|
|
|
|
if args.descriptor:
|
|
sys.exit("-d requires a full dump")
|
|
|
|
elif magic == b"\x5a\xa5\xf0\x0f":
|
|
print("Full image detected")
|
|
f.seek(0x14)
|
|
flmap0, flmap1 = unpack("<II", f.read(8))
|
|
nr = flmap0 >> 24 & 0x7
|
|
frba = flmap0 >> 12 & 0xff0
|
|
fmba = (flmap1 & 0xff) << 4
|
|
if nr >= 2:
|
|
f.seek(frba)
|
|
flreg0, flreg1, flreg2 = unpack("<III", f.read(12))
|
|
fd_start = (flreg0 & 0x1fff) << 12
|
|
fd_end = flreg0 >> 4 & 0x1fff000 | 0xfff + 1
|
|
me_start = (flreg2 & 0x1fff) << 12
|
|
me_end = flreg2 >> 4 & 0x1fff000 | 0xfff + 1
|
|
|
|
if me_start >= me_end:
|
|
sys.exit("The ME/TXE region in this image has been disabled")
|
|
|
|
f.seek(me_start + 0x10)
|
|
if f.read(4) != b"$FPT":
|
|
sys.exit("The ME/TXE region is corrupted or missing")
|
|
|
|
print("The ME/TXE region goes from {:#x} to {:#x}"
|
|
.format(me_start, me_end))
|
|
else:
|
|
sys.exit("This image does not contains a ME/TXE firmware NR = {})"
|
|
.format(nr))
|
|
else:
|
|
sys.exit("Unknown image")
|
|
|
|
print("Found FPT header at {:#x}".format(me_start + 0x10))
|
|
|
|
f.seek(me_start + 0x14)
|
|
entries = unpack("<I", f.read(4))[0]
|
|
print("Found {} partition(s)".format(entries))
|
|
|
|
f.seek(me_start + 0x14)
|
|
header_len = unpack("B", f.read(1))[0]
|
|
|
|
f.seek(me_start + 0x30)
|
|
partitions = f.read(entries * 0x20)
|
|
|
|
ftpr_header = b""
|
|
|
|
for i in range(entries):
|
|
if partitions[i * 0x20:(i * 0x20) + 4] == b"FTPR":
|
|
ftpr_header = partitions[i * 0x20:(i + 1) * 0x20]
|
|
break
|
|
|
|
if ftpr_header == b"":
|
|
sys.exit("FTPR header not found, this image doesn't seem to be valid")
|
|
|
|
ftpr_offset, ftpr_lenght = unpack("<II", ftpr_header[0x08:0x10])
|
|
ftpr_offset += me_start
|
|
print("Found FTPR header: FTPR partition spans from {:#x} to {:#x}"
|
|
.format(ftpr_offset, ftpr_offset + ftpr_lenght))
|
|
|
|
f.seek(ftpr_offset)
|
|
if f.read(4) == b"$CPD":
|
|
me11 = True
|
|
num_entries = unpack("<I", f.read(4))[0]
|
|
ftpr_mn2_offset = 0x10 + num_entries * 0x18
|
|
else:
|
|
me11 = False
|
|
ftpr_mn2_offset = 0
|
|
|
|
f.seek(ftpr_offset + ftpr_mn2_offset + 0x24)
|
|
version = unpack("<HHHH", f.read(0x08))
|
|
print("ME/TXE firmware version {}"
|
|
.format('.'.join(str(i) for i in version)))
|
|
|
|
if not args.check:
|
|
if args.output:
|
|
f.close()
|
|
shutil.copy(args.file, args.output)
|
|
f = open(args.output, "r+b")
|
|
|
|
mef = regionFile(f, me_start, me_end)
|
|
|
|
print("Removing extra partitions...")
|
|
mef.fill_range(me_start + 0x30, ftpr_offset, b"\xff")
|
|
mef.fill_range(ftpr_offset + ftpr_lenght, me_end, b"\xff")
|
|
|
|
print("Removing extra partition entries in FPT...")
|
|
mef.write_to(me_start + 0x30, ftpr_header)
|
|
mef.write_to(me_start + 0x14, pack("<I", 1))
|
|
|
|
print("Removing EFFS presence flag...")
|
|
mef.seek(me_start + 0x24)
|
|
flags = unpack("<I", mef.read(4))[0]
|
|
flags &= ~(0x00000001)
|
|
mef.write_to(me_start + 0x24, pack("<I", flags))
|
|
|
|
if args.descriptor:
|
|
print("Removing ME/TXE R/W access to the other flash regions...")
|
|
fdf = regionFile(f, fd_start, fd_end)
|
|
fdf.write_to(fmba + 0x4, pack("<I", 0x04040000))
|
|
|
|
if me11:
|
|
mef.seek(me_start + 0x10)
|
|
header = bytearray(mef.read(0x20))
|
|
else:
|
|
mef.seek(me_start)
|
|
header = bytearray(mef.read(0x30))
|
|
checksum = (0x100 - (sum(header) - header[0x1b]) & 0xff) & 0xff
|
|
|
|
print("Correcting checksum (0x{:02x})...".format(checksum))
|
|
# The checksum is just the two's complement of the sum of the first
|
|
# 0x30 bytes in ME < 11 or bytes 0x10:0x30 in ME >= 11 (except for
|
|
# 0x1b, the checksum itself). In other words, the sum of those bytes
|
|
# must be always 0x00.
|
|
mef.write_to(me_start + 0x1b, pack("B", checksum))
|
|
|
|
if not me11:
|
|
print("Reading FTPR modules list...")
|
|
mef.seek(ftpr_offset + 0x1c)
|
|
tag = mef.read(4)
|
|
|
|
if tag == b"$MN2":
|
|
mef.seek(ftpr_offset + 0x20)
|
|
num_modules = unpack("<I", mef.read(4))[0]
|
|
mef.seek(ftpr_offset + 0x290)
|
|
data = mef.read(0x84)
|
|
|
|
module_header_size = 0
|
|
if data[0x0:0x4] == b"$MME":
|
|
if data[0x60:0x64] == b"$MME" or num_modules == 1:
|
|
module_header_size = 0x60
|
|
elif data[0x80:0x84] == b"$MME":
|
|
module_header_size = 0x80
|
|
|
|
if module_header_size != 0:
|
|
mef.seek(ftpr_offset + 0x290)
|
|
mod_headers = [mef.read(module_header_size)
|
|
for i in range(0, num_modules)]
|
|
|
|
if all(hdr.startswith(b"$MME") for hdr in mod_headers):
|
|
if args.keep_modules:
|
|
end_addr = ftpr_offset + ftpr_lenght
|
|
else:
|
|
end_addr = remove_modules(mef, mod_headers,
|
|
ftpr_offset, me_end)
|
|
|
|
if args.relocate:
|
|
new_ftpr_offset = relocate_partition(mef,
|
|
me_start, me_end,
|
|
me_start + 0x30,
|
|
min_ftpr_offset + me_start,
|
|
mod_headers)
|
|
end_addr += new_ftpr_offset - ftpr_offset
|
|
ftpr_offset = new_ftpr_offset
|
|
|
|
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 - me_start))
|
|
|
|
if me_start > 0:
|
|
print("The ME region can be reduced up to:\n"
|
|
" {:08x}:{:08x} me"
|
|
.format(me_start, end_addr - 1))
|
|
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")
|
|
else:
|
|
print("Wrong FTPR partition tag ({}); skipping modules removal"
|
|
.format(tag))
|
|
else:
|
|
print("Modules removal in ME v11 or greater is not yet supported")
|
|
|
|
sys.stdout.write("Checking FTPR RSA signature... ")
|
|
if check_partition_signature(f, ftpr_offset + ftpr_mn2_offset):
|
|
print("VALID")
|
|
else:
|
|
print("INVALID!!")
|
|
sys.exit("The FTPR partition signature is not valid. Is the input "
|
|
"ME/TXE image valid?")
|
|
|
|
f.close()
|
|
|
|
if not args.check:
|
|
print("Done! Good luck!")
|