Nicola Corna (nicola@corna.info) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/18473
-gerrit
commit 8d09bfb97f9afb7e18cc131b742946a3aae9fe09 Author: Nicola Corna nicola@corna.info Date: Wed Feb 22 10:16:32 2017 +0100
util/me_cleaner: Pull the latest changes from upstream
Relevant changes (commit 250b2ec): * Fix a bug for ME6 Ignition images. * Fix signature checking for ME11 and later. * Add command line arguments. * Add an option to relocate the FTPR partition to the top of the ME region, recovering most of the ME region space. * Print the image minimum size. * Add write boundary checks, to prevent writes on other regions in case of bugs.
The new changes have been tested on multiple platforms by the me_cleaner users. They have been tested also on the author's X220T with coreboot, where the ME region has been shrinked up to 84 kB without any issue.
Change-Id: I3bd6b4cba9f5eebc3cd4892dd9f188744a06c42b Signed-off-by: Nicola Corna nicola@corna.info --- util/me_cleaner/README.md | 3 +- util/me_cleaner/me_cleaner.py | 438 ++++++++++++++++++++++++++++++------------ 2 files changed, 317 insertions(+), 124 deletions(-)
diff --git a/util/me_cleaner/README.md b/util/me_cleaner/README.md index 9a09b55..0ca3d32 100644 --- a/util/me_cleaner/README.md +++ b/util/me_cleaner/README.md @@ -12,7 +12,8 @@ Currently this tool: * Removes any partition except for the fundamental one (FTPR) * Removes the EFFS presence flag * Corrects the FPT checksum - * Removes any non-essential LZMA or Huffman compressed module (pre-Skylake only) + * Removes any non-essential LZMA or Huffman compressed module from the FTPR partition (pre-Skylake only) + * Relocates the remaining parts of the FTPR partition to the top of the ME region (pre-Skylake only) * Checks the validity of the RSA signature of the FTPR partition
Don't forget to power cycle your PC after flashing the modified ME/TXE image diff --git a/util/me_cleaner/me_cleaner.py b/util/me_cleaner/me_cleaner.py index 2ad5898..8ca5498 100755 --- a/util/me_cleaner/me_cleaner.py +++ b/util/me_cleaner/me_cleaner.py @@ -18,12 +18,70 @@ 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 @@ -50,19 +108,13 @@ def get_chunks_offsets(llut, me_start): return offsets
-def fill_range(f, start, end, fill): - block = fill * 4096 - f.seek(start) - f.writelines(itertools.repeat(block, (end - start) // 4096)) - f.write(block[:(end - start) % 4096]) - - -def remove_modules(f, mod_headers, ftpr_offset): +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") @@ -78,9 +130,11 @@ def remove_modules(f, mod_headers, ftpr_offset): .format(offset, offset + size))
if name in unremovable_modules: + end_addr = max(end_addr, offset + size) print("NOT removed, essential") else: - fill_range(f, offset, offset + size, b"\xff") + end = min(offset + size, me_end) + f.fill_range(offset, end, b"\xff") print("removed")
elif comp_type == 0x01: @@ -93,10 +147,9 @@ def remove_modules(f, mod_headers, ftpr_offset):
chunk_count = unpack("<I", llut[0x4:0x8])[0] base = unpack("<I", llut[0x8:0xc])[0] + 0x10000000 - huff_data_len = unpack("<I", llut[0x10:0x14])[0] chunk_size = unpack("<I", llut[0x30:0x34])[0]
- llut += f.read(chunk_count * 4 + huff_data_len) + 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") @@ -129,14 +182,20 @@ def remove_modules(f, mod_headers, ftpr_offset):
for removable_chunk in removable_huff_chunks: if removable_chunk[1] > removable_chunk[0]: - fill_range(f, removable_chunk[0], removable_chunk[1], b"\xff") + 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 = int(binascii.hexlify(f.read(0x4)[::-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 @@ -152,144 +211,274 @@ def check_partition_signature(f, offset): return "{:#x}".format(decrypted_sig).endswith(sha256.hexdigest()) # FIXME
-if len(sys.argv) != 2 or sys.argv[1] == "-h" or sys.argv[1] == "--help": - print("Usage: \n" - " me_cleaner.py me_or_txe_image.bin\n" - "or\n" - " me_cleaner.py full_dump.bin") -else: - with open(sys.argv[1], "r+b") as f: - f.seek(0x10) - magic = f.read(4) - - if magic == b"$FPT": - print("ME/TXE image detected") - me_start = 0 - f.seek(0, 2) - me_end = f.tell() - - elif magic == b"\x5a\xa5\xf0\x0f": - print("Full image detected") - f.seek(0x14) - flmap0 = unpack("<I", f.read(4))[0] - nr = flmap0 >> 24 & 0x7 - frba = flmap0 >> 12 & 0xff0 - if nr >= 2: - f.seek(frba + 0x8) - flreg2 = unpack("<I", f.read(4))[0] - me_start = (flreg2 & 0x1fff) << 12 - me_end = flreg2 >> 4 & 0x1fff000 | 0xfff - - if me_start >= me_end: - sys.exit("The ME/TXE region in this image has been " - "disabled") - - f.seek(me_start + 0x10) - if f.read(4) != b"$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)) +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("Unknown image") + 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)) + 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) + 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 + 0x14) + header_len = unpack("B", f.read(1))[0]
- f.seek(me_start + 0x30) - partitions = f.read(entries * 0x20) + f.seek(me_start + 0x30) + partitions = f.read(entries * 0x20)
- ftpr_header = b"" + 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 + 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") + 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)) - print("Removing extra partitions...") + 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")
- fill_range(f, me_start + 0x30, ftpr_offset, b"\xff") - fill_range(f, ftpr_offset + ftpr_lenght, me_end, b"\xff") + 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...") - f.seek(me_start + 0x30) - f.write(ftpr_header) - f.seek(me_start + 0x14) - f.write(pack("<I", 1)) + mef.write_to(me_start + 0x30, ftpr_header) + mef.write_to(me_start + 0x14, pack("<I", 1))
print("Removing EFFS presence flag...") - f.seek(me_start + 0x24) - flags = unpack("<I", f.read(4))[0] + mef.seek(me_start + 0x24) + flags = unpack("<I", mef.read(4))[0] flags &= ~(0x00000001) - f.seek(me_start + 0x24) - f.write(pack("<I", flags)) + mef.write_to(me_start + 0x24, pack("<I", flags))
- f.seek(me_start, 0) - header = bytearray(f.read(0x30)) + 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 (except for 0x1b, the checksum itself). In other words, - # the sum of the first 0x30 bytes must be always 0x00. - f.seek(me_start + 0x1b) - f.write(pack("B", checksum)) - - f.seek(ftpr_offset) - if f.read(4) == b"$CPD": - me11 = True - num_entries = unpack("<I", f.read(4))[0] - f.seek(ftpr_offset + 0x10 + num_entries * 0x18 + 0x24) - else: - me11 = False - f.seek(ftpr_offset + 0x24) - - version = unpack("<HHHH", f.read(0x08)) - print("ME/TXE firmware version {}" - .format('.'.join(str(i) for i in version))) + # 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...") - f.seek(ftpr_offset + 0x1c) - tag = f.read(4) + mef.seek(ftpr_offset + 0x1c) + tag = mef.read(4)
if tag == b"$MN2": - f.seek(ftpr_offset + 0x20) - num_modules = unpack("<I", f.read(4))[0] - f.seek(ftpr_offset + 0x290) - data = f.read(0x84) + mef.seek(ftpr_offset + 0x20) + num_modules = unpack("<I", mef.read(4))[0] + mef.seek(ftpr_offset + 0x290) + data = mef.read(0x84)
module_header_size = 0 if data[0x0:0x4] == b"$MME": - if data[0x60:0x64] == b"$MME": + if data[0x60:0x64] == b"$MME" or num_modules == 1: module_header_size = 0x60 elif data[0x80:0x84] == b"$MME": module_header_size = 0x80
if module_header_size != 0: - f.seek(ftpr_offset + 0x290) - mod_headers = [f.read(module_header_size) + mef.seek(ftpr_offset + 0x290) + mod_headers = [mef.read(module_header_size) for i in range(0, num_modules)]
- if all(mod_h.startswith(b"$MME") for mod_h in mod_headers): - remove_modules(f, mod_headers, ftpr_offset) + 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") @@ -302,12 +491,15 @@ else: 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): - print("VALID") - else: - print("INVALID!!") - sys.exit("The FTPR partition signature is not valid. Is the input " - "ME/TXE image valid?") + 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!")