binmerge.py

#!/usr/bin/python3

import os
import lief
import argparse

lib_exceptions = [ "libc.so.6", "libc.so" ]
if 'LD_LIBRARY_PATH' in os.environ:
    lib_dirs = os.environ['LD_LIBRARY_PATH'].split(os.pathsep)
else:
    lib_dirs = list()
lib_dirs.append('/usr/lib')
lib_dirs.append('/lib')


def find_lib(filename):
    for lib_dir in lib_dirs:
        path = os.path.join(lib_dir, filename)
        if os.path.exists(path):
            return path
    raise

def merge(path):
    # Parse the binary
    binary = lief.parse(path)
    imported_libs_filename = binary.libraries
    imported_symbols = [symbol.name for symbol in binary.imported_symbols]

    # Get and Parse its libraries
    print("Imported libs: {}".format(imported_libs_filename))
    libs = list()
    for lib_name in imported_libs_filename:
        if lib_name in lib_exceptions:
            continue
        lib_path = find_lib(lib_name)
        lib = lief.parse(lib_path)
        libs.append(lib)
    print("Loaded {} libs".format(len(libs)))

    for lib in libs:
        print("Merging", lib.name)
        code_segment = None
        # Merge the LOAD sections
        for segment in lib.segments:
            if segment.type == lief.ELF.SEGMENT_TYPES.LOAD:
                segment_address = binary.add(segment)
                if segment.has(lief.ELF.SEGMENT_FLAGS.X):
                    code_segment = segment_address
        # Relocate the symbols
        for symbol_name in imported_symbols:
            if lib.has_symbol(symbol_name):
                lib_symbol = lib.get_symbol(symbol_name)
                if lib_symbol.exported:
                    hook_symbol = lib.get_symbol(symbol_name)
                    symbol = binary.get_symbol(symbol_name)
                    symbol = code_segment.virtual_address + hook_symbol.value
                    binary.remove_symbol(symbol_name)
                    print("Dynamic symbol removed:", symbol_name)

    # Drop the imported libraries
    for lib in libs:
        binary.remove_library(lib.name)

    # Dump the resulting file
    output_name = os.path.basename(path) + "_merged"
    binary.write(output_name)
    print("Result file written to", output_name)

def check(path):
    if lief.is_pe(path):
        print("PE not supported")
        return -1
    if lief.is_macho(path):
        print("Macho not supported")
        return -1
    if lief.is_elf(path):
        return 0
    return -1

def main():
    arg_parser = argparse.ArgumentParser(description='Merge binary and shared library')
    arg_parser.add_argument('binary_path',
                            metavar='binary',
                            type=str,
                            help='Binary file to merge')
    args = arg_parser.parse_args()

    if check(args.binary_path) is not 0:
        return -1

    merge(args.binary_path)

if __name__ == "__main__":
    main()