def obfuscate(self, obfuscation_info: Obfuscation):
self.logger.info('Running "{0}" obfuscator'.format(self.__class__.__name__))
try:
for smali_file in util.show_list_progress(obfuscation_info.get_smali_files(),
interactive=obfuscation_info.interactive,
description='Inserting arithmetic computations in smali files'):
self.logger.debug('Inserting arithmetic computations in file "{0}"'.format(smali_file))
with util.inplace_edit_file(smali_file) as current_file:
editing_method = False
start_label = None
end_label = None
for line in current_file:
if line.startswith('.method ') and ' abstract ' not in line and \
' native ' not in line and not editing_method:
# Entering method.
print(line, end='')
editing_method = True
elif line.startswith('.end method') and editing_method:
# Exiting method.
if start_label and end_label:
print('\t:{0}'.format(end_label))
print('\tgoto/32 :{0}'.format(start_label))
start_label = None
end_label = None
print(line, end='')
editing_method = False
elif editing_method:
# Inside method.
print(line, end='')
match = util.locals_pattern.match(line)
if match and int(match.group('local_count')) >= 2:
# If there are at least 2 registers available, add a fake branch at the beginning of
# the method: one branch will continue from here, the other branch will go to the end
# of the method and then will return here through a "goto" instruction.
v0, v1 = util.get_random_int(1, 32), util.get_random_int(1, 32)
start_label = util.get_random_string(16)
end_label = util.get_random_string(16)
tmp_label = util.get_random_string(16)
print('\n\tconst v0, {0}'.format(v0))
print('\tconst v1, {0}'.format(v1))
print('\tadd-int v0, v0, v1')
print('\trem-int v0, v0, v1')
print('\tif-gtz v0, :{0}'.format(tmp_label))
print('\tgoto/32 :{0}'.format(end_label))
print('\t:{0}'.format(tmp_label))
print('\t:{0}'.format(start_label))
else:
print(line, end='')
except Exception as e:
self.logger.error('Error during execution of "{0}" obfuscator: {1}'.format(self.__class__.__name__, e))
raise
finally:
obfuscation_info.used_obfuscators.append(self.__class__.__name__)
def obfuscate(self, obfuscation_info: Obfuscation):
self.logger.info('Running "{0}" obfuscator'.format(self.__class__.__name__))
try:
op_codes = util.get_nop_valid_op_codes()
pattern = re.compile(r'\s+(?P<op_code>\S+)')
for smali_file in util.show_list_progress(obfuscation_info.get_smali_files(),
interactive=obfuscation_info.interactive,
description='Inserting "nop" instructions in smali files'):
self.logger.debug('Inserting "nop" instructions in file "{0}"'.format(smali_file))
with util.inplace_edit_file(smali_file) as current_file:
for line in current_file:
# Print original instruction.
print(line, end='')
# Check if this line contains an op code at the beginning of the string.
match = pattern.match(line)
if match:
op_code = match.group('op_code')
# If this is a valid op code, insert some nop instructions after it.
if op_code in op_codes:
nop_count = util.get_random_int(1, 5)
print('\tnop\n' * nop_count, end='')
except Exception as e:
self.logger.error('Error during execution of "{0}" obfuscator: {1}'.format(self.__class__.__name__, e))
raise
finally:
obfuscation_info.used_obfuscators.append(self.__class__.__name__)
def add_random_fields(self, original_field_declaration: str):
if self.added_fields < self.max_fields_to_add:
for _ in range(util.get_random_int(1, 4)):
print('\n', end='')
print(original_field_declaration.replace(
':', '{0}:'.format(util.get_random_string(8))),
end='')
self.added_fields += 1
def rename_field_declarations(self,
smali_files: List[str],
interactive: bool = False) -> Set[str]:
renamed_fields: Set[str] = set()
# Search for field definitions that can be renamed.
for smali_file in util.show_list_progress(
smali_files,
interactive=interactive,
description="Renaming field declarations",
):
with util.inplace_edit_file(smali_file) as (in_file, out_file):
for line in in_file:
# Field declared in class.
field_match = util.field_pattern.match(line)
if field_match:
field_name = field_match.group("field_name")
# Avoid sub-fields.
if "$" not in field_name:
# Rename field declaration (usages of this field will be
# renamed later) and add some random fields.
line = line.replace(
"{0}:".format(field_name),
"{0}:".format(self.rename_field(field_name)),
)
out_file.write(line)
# Add random fields.
if self.added_fields < self.max_fields_to_add:
for _ in range(util.get_random_int(1, 4)):
out_file.write("\n")
out_file.write(
line.replace(
":",
"{0}:".format(
util.get_random_string(8)),
))
self.added_fields += 1
field = "{field_name}:{field_type}".format(
field_name=field_match.group("field_name"),
field_type=field_match.group("field_type"),
)
renamed_fields.add(field)
else:
out_file.write(line)
else:
out_file.write(line)
return renamed_fields
