BIOSUtilities/Apple_EFI_IM4P.py
Plato Mavropoulos d85a7f82dc Added AMI PFAT RSA 3K signed blocks support
Added AMI PFAT nested detection at each file

Added Award BIOS payload naming at each file

Switched Panasonic BIOS LZNT1 external library

Improved Panasonic LZNT1 detection and length

Improved Dell PFS code structure and fixed bugs

Improved code exception handling (raise, catch)

Improved code definitions (PEP8, docs, types)

Fixed some arguments missing from help screens
2024-04-24 01:22:53 +03:00

147 lines
5.1 KiB
Python

#!/usr/bin/env python3 -B
# coding=utf-8
"""
Apple EFI IM4P
Apple EFI IM4P Splitter
Copyright (C) 2018-2024 Plato Mavropoulos
"""
import os
from common.path_ops import make_dirs, path_stem
from common.patterns import PAT_APPLE_IM4P, PAT_INTEL_IFD
from common.system import printer
from common.templates import BIOSUtility
from common.text_ops import file_to_bytes
TITLE = 'Apple EFI IM4P Splitter v4.0'
def is_apple_im4p(input_file):
""" Check if input is Apple EFI IM4P image """
input_buffer = file_to_bytes(input_file)
is_im4p = PAT_APPLE_IM4P.search(input_buffer)
is_ifd = PAT_INTEL_IFD.search(input_buffer)
return bool(is_im4p and is_ifd)
def apple_im4p_split(input_file, extract_path, padding=0):
""" Parse & Split Apple EFI IM4P image """
exit_codes = []
input_buffer = file_to_bytes(input_file)
make_dirs(extract_path, delete=True)
# Detect IM4P EFI pattern
im4p_match = PAT_APPLE_IM4P.search(input_buffer)
# After IM4P mefi (0x15), multi EFI payloads have _MEFIBIN (0x100) but is difficult to RE w/o varying samples.
# However, _MEFIBIN is not required for splitting SPI images due to Intel Flash Descriptor Components Density.
# IM4P mefi payload start offset
mefi_data_bgn = im4p_match.start() + input_buffer[im4p_match.start() - 0x1]
# IM4P mefi payload size
mefi_data_len = int.from_bytes(input_buffer[im4p_match.end() + 0x5:im4p_match.end() + 0x9], 'big')
# Check if mefi is followed by _MEFIBIN
mefibin_exist = input_buffer[mefi_data_bgn:mefi_data_bgn + 0x8] == b'_MEFIBIN'
# Actual multi EFI payloads start after _MEFIBIN
efi_data_bgn = mefi_data_bgn + 0x100 if mefibin_exist else mefi_data_bgn
# Actual multi EFI payloads size without _MEFIBIN
efi_data_len = mefi_data_len - 0x100 if mefibin_exist else mefi_data_len
# Adjust input file buffer to actual multi EFI payloads data
input_buffer = input_buffer[efi_data_bgn:efi_data_bgn + efi_data_len]
# Parse Intel Flash Descriptor pattern matches
for ifd in PAT_INTEL_IFD.finditer(input_buffer):
# Component Base Address from FD start (ICH8-ICH10 = 1, IBX = 2, CPT+ = 3)
ifd_flmap0_fcba = input_buffer[ifd.start() + 0x4] * 0x10
# I/O Controller Hub (ICH)
if ifd_flmap0_fcba == 0x10:
# At ICH, Flash Descriptor starts at 0x0
ifd_bgn_substruct = 0x0
# 0xBC for [0xAC] + 0xFF * 16 sanity check
ifd_end_substruct = 0xBC
# Platform Controller Hub (PCH)
else:
# At PCH, Flash Descriptor starts at 0x10
ifd_bgn_substruct = 0x10
# 0xBC for [0xAC] + 0xFF * 16 sanity check
ifd_end_substruct = 0xBC
# Actual Flash Descriptor Start Offset
ifd_match_start = ifd.start() - ifd_bgn_substruct
# Actual Flash Descriptor End Offset
ifd_match_end = ifd.end() - ifd_end_substruct
# Calculate Intel Flash Descriptor Flash Component Total Size
# Component Count (00 = 1, 01 = 2)
ifd_flmap0_nc = ((int.from_bytes(input_buffer[ifd_match_end:ifd_match_end + 0x4], 'little') >> 8) & 3) + 1
# PCH/ICH Strap Length (ME 2-8 & TXE 0-2 & SPS 1-2 <= 0x12, ME 9+ & TXE 3+ & SPS 3+ >= 0x13)
ifd_flmap1_isl = input_buffer[ifd_match_end + 0x7]
# Component Density Byte (ME 2-8 & TXE 0-2 & SPS 1-2 = 0:5, ME 9+ & TXE 3+ & SPS 3+ = 0:7)
ifd_comp_den = input_buffer[ifd_match_start + ifd_flmap0_fcba]
# Component 1 Density Bits (ME 2-8 & TXE 0-2 & SPS 1-2 = 3, ME 9+ & TXE 3+ & SPS 3+ = 4)
ifd_comp_1_bitwise = 0xF if ifd_flmap1_isl >= 0x13 else 0x7
# Component 2 Density Bits (ME 2-8 & TXE 0-2 & SPS 1-2 = 3, ME 9+ & TXE 3+ & SPS 3+ = 4)
ifd_comp_2_bitwise = 0x4 if ifd_flmap1_isl >= 0x13 else 0x3
# Component 1 Density (FCBA > C0DEN)
ifd_comp_all_size = IFD_COMP_LEN[ifd_comp_den & ifd_comp_1_bitwise]
# Component 2 Density (FCBA > C1DEN)
if ifd_flmap0_nc == 2:
ifd_comp_all_size += IFD_COMP_LEN[ifd_comp_den >> ifd_comp_2_bitwise]
ifd_data_bgn = ifd_match_start
ifd_data_end = ifd_data_bgn + ifd_comp_all_size
ifd_data_txt = f'0x{ifd_data_bgn:07X}-0x{ifd_data_end:07X}'
output_data = input_buffer[ifd_data_bgn:ifd_data_end]
output_size = len(output_data)
output_name = path_stem(input_file) if os.path.isfile(input_file) else 'Part'
output_path = os.path.join(extract_path, f'{output_name}_[{ifd_data_txt}].fd')
with open(output_path, 'wb') as output_image:
output_image.write(output_data)
printer(f'Split Apple EFI image at {ifd_data_txt}!', padding)
if output_size != ifd_comp_all_size:
printer(f'Error: Bad image size 0x{output_size:07X}, expected 0x{ifd_comp_all_size:07X}!', padding + 4)
exit_codes.append(1)
return sum(exit_codes)
# Intel Flash Descriptor Component Sizes (4MB, 8MB, 16MB and 32MB)
IFD_COMP_LEN = {3: 0x400000, 4: 0x800000, 5: 0x1000000, 6: 0x2000000}
if __name__ == '__main__':
BIOSUtility(title=TITLE, check=is_apple_im4p, main=apple_im4p_split).run_utility()