MetalMonday/me_cleaner
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Do not set the HAP/AltMeDisable bit by default

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While some BIOS behaves better with the bit set, others don't. As
me_cleaner has been already tested on many platforms (and we don't want to
break things if it previously worked), revert to the default behaviour
and add an option (-S) to optionally set the HAP/AltMeDisable bit.

So now the situation is:
 -s: just set the HAP/AltMeDisable bit, without modifying the firmware
 -S: modify the firmware and set the HAP/AltMeDisable bit
 none of them: modify the firmware but don't set the HAP/AltMeDisable bit
This commit is contained in:
Nicola Corna 2017-09-01 16:59:24 +02:00
parent 72fff7a98e
commit d5705b62f8
1 changed files with 35 additions and 24 deletions
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59
me_cleaner.py
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@ -436,14 +436,22 @@ 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()
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")
parser.add_argument("-s", "--soft-disable", help="instead of modifying "
"the Intel ME firmware, just disable it by setting "
"the MeAltDisable bit or the HAP bit (requires a full "
"dump)", action="store_true")
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")
@ -470,11 +478,11 @@ if __name__ == "__main__":
args = parser.parse_args()
if args.check and (args.soft_disable or args.relocate or \
args.descriptor or args.truncate or args.output):
sys.exit("-c can't be used with -s, -r, -d, -t or -O")
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 and (args.relocate or args.truncate):
if args.soft_disable_only and (args.relocate or args.truncate):
sys.exit("-s can't be used with -r or -t")
f = open(args.file, "rb" if args.check or args.output else "r+b")
@ -485,8 +493,8 @@ if __name__ == "__main__":
print("ME/TXE image detected")
if args.descriptor or args.extract_descriptor or args.extract_me or \
args.soft_disable:
sys.exit("-d, -D, -M and -s require a full dump")
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)
@ -523,6 +531,8 @@ if __name__ == "__main__":
else:
sys.exit("Unknown image")
end_addr = me_end
print("Found FPT header at {:#x}".format(me_start + 0x10))
f.seek(me_start + 0x14)
@ -595,7 +605,7 @@ if __name__ == "__main__":
fdf = RegionFile(f, fd_start, fd_end)
if not args.check:
if not args.soft_disable:
if not args.soft_disable_only:
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")
@ -655,19 +665,20 @@ if __name__ == "__main__":
print("Truncating file at {:#x}...".format(end_addr))
f.truncate(end_addr)
if me11:
print("Setting the HAP bit in PCHSTRP0 to disable Intel ME...")
fdf.seek(fpsba)
pchstrp0 = unpack("<I", fdf.read(4))[0]
pchstrp0 |= (1 << 16)
fdf.write_to(fpsba, pack("<I", pchstrp0))
else:
print("Setting the AltMeDisable bit in PCHSTRP10 to disable Intel "
"ME...")
fdf.seek(fpsba + 0x28)
pchstrp10 = unpack("<I", fdf.read(4))[0]
pchstrp10 |= (1 << 7)
fdf.write_to(fpsba + 0x28, pack("<I", pchstrp10))
if args.soft_disable or args.soft_disable_only:
if me11:
print("Setting the HAP bit in PCHSTRP0 to disable Intel ME...")
fdf.seek(fpsba)
pchstrp0 = unpack("<I", fdf.read(4))[0]
pchstrp0 |= (1 << 16)
fdf.write_to(fpsba, pack("<I", pchstrp0))
else:
print("Setting the AltMeDisable bit in PCHSTRP10 to disable "
"Intel ME...")
fdf.seek(fpsba + 0x28)
pchstrp10 = unpack("<I", fdf.read(4))[0]
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...")