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Move the region offset inside RegionFile

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This commit is contained in:
Nicola Corna 2018-01-06 15:56:20 +01:00
parent 80b00b9a74
commit 604e1bf812
1 changed files with 89 additions and 83 deletions
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172
me_cleaner.py
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@ -59,27 +59,35 @@ class RegionFile:
self.region_end = region_end
def read(self, n):
return self.f.read(n)
if f.tell() + n <= self.region_end:
return self.f.read(n)
else:
raise OutOfRegionException()
def readinto(self, b):
return self.f.readinto(b)
if f.tell() + len(b) <= self.region_end:
return self.f.readinto(b)
else:
raise OutOfRegionException()
def seek(self, offset):
return self.f.seek(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 offset >= self.region_start and \
offset + len(data) <= self.region_end:
self.f.seek(offset)
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 start >= self.region_start and end <= self.region_end:
if self.region_start + end <= self.region_end:
if start < end:
block = fill * 4096
self.f.seek(start)
self.f.seek(self.region_start + start)
self.f.writelines(itertools.repeat(block,
(end - start) // 4096))
self.f.write(block[:(end - start) % 4096])
@ -87,31 +95,32 @@ class RegionFile:
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:
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(offset_from + i, 0)
self.f.seek(self.region_start + offset_from + i, 0)
block = self.f.read(min(size - i, 4096))
self.f.seek(offset_from + i, 0)
self.f.seek(self.region_start + offset_from + i, 0)
self.f.write(fill * len(block))
self.f.seek(offset_to + i, 0)
self.f.seek(self.region_start + offset_to + i, 0)
self.f.write(block)
else:
raise OutOfRegionException()
def save(self, filename, size):
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
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, me_start):
def get_chunks_offsets(llut):
chunk_count = unpack("<I", llut[0x04:0x08])[0]
huffman_stream_end = sum(unpack("<II", llut[0x10:0x18])) + me_start
huffman_stream_end = sum(unpack("<II", llut[0x10:0x18]))
nonzero_offsets = [huffman_stream_end]
offsets = []
@ -120,7 +129,7 @@ def get_chunks_offsets(llut, me_start):
offset = 0
if chunk[3] != 0x80:
offset = unpack("<I", chunk[0:3] + b"\x00")[0] + me_start
offset = unpack("<I", chunk[0:3] + b"\x00")[0]
offsets.append([offset, 0])
if offset != 0:
@ -176,7 +185,7 @@ def remove_modules(f, mod_headers, ftpr_offset, me_end):
chunk_size = unpack("<I", llut[0x30:0x34])[0]
llut += f.read(chunk_count * 4)
chunks_offsets = get_chunks_offsets(llut, me_start)
chunks_offsets = get_chunks_offsets(llut)
else:
sys.exit("Huffman modules found, but LLUT is not present")
@ -255,14 +264,13 @@ def print_check_partition_signature(f, offset):
"ME/TXE image valid?")
def relocate_partition(f, me_start, me_end, partition_header_offset,
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))
old_offset += me_start
llut_start = 0
for mod_header in mod_headers:
@ -278,8 +286,7 @@ def relocate_partition(f, me_start, me_end, partition_header_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)
lut_start_corr - llut_start - 0x40 + old_offset)
new_offset = ((new_offset + 0x1f) // 0x20) * 0x20
offset_diff = new_offset - old_offset
@ -289,15 +296,14 @@ def relocate_partition(f, me_start, me_end, partition_header_offset,
print(" Adjusting FPT entry...")
f.write_to(partition_header_offset + 0x8,
pack("<I", new_offset - me_start))
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 - me_start
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...")
@ -330,7 +336,7 @@ def relocate_partition(f, me_start, me_end, partition_header_offset,
return new_offset
def check_and_remove_modules(f, me_start, me_end, offset, min_offset,
def check_and_remove_modules(f, me_end, offset, min_offset,
relocate, keep_modules):
f.seek(offset + 0x20)
@ -358,9 +364,7 @@ def check_and_remove_modules(f, me_start, me_end, offset, min_offset,
offset, me_end)
if args.relocate:
new_offset = relocate_partition(f, me_start, me_end,
me_start + 0x30,
min_offset + me_start,
new_offset = relocate_partition(f, me_end, 0x30, min_offset,
mod_headers)
end_addr += new_offset - offset
offset = new_offset
@ -377,7 +381,7 @@ def check_and_remove_modules(f, me_start, me_end, offset, min_offset,
return -1, offset
def check_and_remove_modules_me11(f, me_start, me_end, partition_offset,
def check_and_remove_modules_me11(f, me_end, partition_offset,
partition_length, min_offset, relocate,
keep_modules):
@ -435,8 +439,7 @@ def check_and_remove_modules_me11(f, me_start, me_end, partition_offset,
end_data = max(end_data, end)
if relocate:
new_offset = relocate_partition(f, me_start, me_end, me_start + 0x30,
min_offset + me_start, [])
new_offset = relocate_partition(f, me_end, 0x30, min_offset, [])
end_data += new_offset - partition_offset
partition_offset = new_offset
@ -538,9 +541,10 @@ if __name__ == "__main__":
args.soft_disable or args.soft_disable_only:
sys.exit("-d, -D, -M, -S and -s require a full dump")
me_start = 0
f.seek(0, 2)
me_start = 0
me_end = f.tell()
mef = RegionFile(f, me_start, me_end + 1)
elif magic == b"\x5a\xa5\xf0\x0f":
print("Full image detected")
@ -564,8 +568,10 @@ if __name__ == "__main__":
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"$FPT":
mef = RegionFile(f, me_start, me_end + 1)
mef.seek(0x10)
if mef.read(4) != b"$FPT":
sys.exit("The ME/TXE region is corrupted or missing")
print("The ME/TXE region goes from {:#x} to {:#x}"
@ -575,14 +581,14 @@ if __name__ == "__main__":
end_addr = me_end
print("Found FPT header at {:#x}".format(me_start + 0x10))
print("Found FPT header at {:#x}".format(mef.region_start + 0x10))
f.seek(me_start + 0x14)
entries = unpack("<I", f.read(4))[0]
mef.seek(0x14)
entries = unpack("<I", mef.read(4))[0]
print("Found {} partition(s)".format(entries))
f.seek(me_start + 0x30)
partitions = f.read(entries * 0x20)
mef.seek(0x30)
partitions = mef.read(entries * 0x20)
ftpr_header = b""
@ -595,20 +601,19 @@ if __name__ == "__main__":
sys.exit("FTPR header not found, this image doesn't seem to be valid")
ftpr_offset, ftpr_length = 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_length))
f.seek(ftpr_offset)
if f.read(4) == b"$CPD":
mef.seek(ftpr_offset)
if mef.read(4) == b"$CPD":
me11 = True
num_entries = unpack("<I", f.read(4))[0]
num_entries = unpack("<I", mef.read(4))[0]
f.seek(ftpr_offset + 0x10)
mef.seek(ftpr_offset + 0x10)
ftpr_mn2_offset = -1
for i in range(0, num_entries):
data = f.read(0x18)
data = mef.read(0x18)
name = data[0x0:0xc].rstrip(b"\x00").decode("ascii")
offset = unpack("<I", data[0xc:0xf] + b"\x00")[0]
@ -617,24 +622,24 @@ if __name__ == "__main__":
break
if ftpr_mn2_offset >= 0:
check_mn2_tag(f, ftpr_offset + ftpr_mn2_offset)
check_mn2_tag(mef, ftpr_offset + ftpr_mn2_offset)
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(f, ftpr_offset)
check_mn2_tag(mef, ftpr_offset)
me11 = False
ftpr_mn2_offset = 0
f.seek(ftpr_offset + ftpr_mn2_offset + 0x24)
version = unpack("<HHHH", f.read(0x08))
mef.seek(ftpr_offset + ftpr_mn2_offset + 0x24)
version = unpack("<HHHH", mef.read(0x08))
print("ME/TXE firmware version {}"
.format('.'.join(str(i) for i in version)))
f.seek(ftpr_offset + ftpr_mn2_offset + 0x80)
pubkey_md5 = hashlib.md5(f.read(0x104)).hexdigest()
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]
@ -655,10 +660,10 @@ if __name__ == "__main__":
shutil.copy(args.file, args.output)
f = open(args.output, "r+b")
mef = RegionFile(f, me_start, me_end)
mef = RegionFile(f, me_start, me_end + 1)
if me_start > 0:
fdf = RegionFile(f, fd_start, fd_end)
fdf = RegionFile(f, fd_start, fd_end + 1)
if not args.check:
if not args.soft_disable_only:
@ -708,32 +713,31 @@ if __name__ == "__main__":
extra_part_end = max(extra_part_end, part_end)
print("NOT removed")
else:
mef.fill_range(me_start + part_start,
me_start + part_end, b"\xff")
mef.fill_range(part_start, part_end, b"\xff")
print("removed")
print("Removing partition entries in FPT...")
mef.write_to(me_start + 0x30, unremovable_part_fpt)
mef.write_to(me_start + 0x14,
mef.write_to(0x30, unremovable_part_fpt)
mef.write_to(0x14,
pack("<I", len(unremovable_part_fpt) // 0x20))
mef.fill_range(me_start + 0x30 + len(unremovable_part_fpt),
me_start + 0x30 + len(partitions), b"\xff")
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(me_start + 0x24)
mef.seek(0x24)
flags = unpack("<I", mef.read(4))[0]
flags &= ~(0x00000001)
mef.write_to(me_start + 0x24, pack("<I", flags))
mef.write_to(0x24, pack("<I", flags))
if me11:
mef.seek(me_start + 0x10)
mef.seek(0x10)
header = bytearray(mef.read(0x20))
header[0x0b] = 0x00
else:
mef.seek(me_start)
mef.seek(0)
header = bytearray(mef.read(0x30))
header[0x1b] = 0x00
checksum = (0x100 - sum(header) & 0xff) & 0xff
@ -743,19 +747,19 @@ if __name__ == "__main__":
# 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))
mef.write_to(0x1b, pack("B", checksum))
print("Reading FTPR modules list...")
if me11:
end_addr, ftpr_offset = \
check_and_remove_modules_me11(mef, me_start, me_end,
check_and_remove_modules_me11(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_start, me_end, ftpr_offset,
check_and_remove_modules(mef, me_end, ftpr_offset,
min_ftpr_offset, args.relocate,
args.keep_modules)
@ -765,11 +769,12 @@ if __name__ == "__main__":
end_addr += spared_blocks * 0x1000
print("The ME minimum size should be {0} bytes "
"({0:#x} bytes)".format(end_addr - me_start))
"({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, end_addr - 1))
" {: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)
@ -808,12 +813,14 @@ if __name__ == "__main__":
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, end_addr - 1))
.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, end_addr, bios_end - 1))
.format(bios_start, bios_end - 1,
me_start + end_addr, bios_end - 1))
flreg1 = start_end_to_flreg(end_addr, bios_end)
flreg2 = start_end_to_flreg(me_start, end_addr)
flreg1 = start_end_to_flreg(me_start + end_addr, bios_end)
flreg2 = start_end_to_flreg(me_start, me_start + end_addr)
fdf_copy.seek(frba + 0x4)
fdf_copy.write(pack("<II", flreg1, flreg2))
@ -833,7 +840,7 @@ if __name__ == "__main__":
if args.truncate:
print("Extracting and truncating the ME image to \"{}\"..."
.format(args.extract_me))
mef_copy = mef.save(args.extract_me, end_addr - me_start)
mef_copy = mef.save(args.extract_me, end_addr)
else:
print("Extracting the ME image to \"{}\"..."
.format(args.extract_me))
@ -841,12 +848,11 @@ if __name__ == "__main__":
print("Checking the FTPR RSA signature of the extracted ME image... ",
end="")
print_check_partition_signature(mef_copy, ftpr_offset +
ftpr_mn2_offset - me_start)
print_check_partition_signature(mef_copy, ftpr_offset + ftpr_mn2_offset)
mef_copy.close()
print("Checking the FTPR RSA signature... ", end="")
print_check_partition_signature(f, ftpr_offset + ftpr_mn2_offset)
print_check_partition_signature(mef, ftpr_offset + ftpr_mn2_offset)
f.close()