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- from __future__ import unicode_literals
-
- import collections
- import io
- import struct
- import zlib
-
- from .utils import (
- compat_str,
- ExtractorError,
- )
-
-
- def _extract_tags(file_contents):
- if file_contents[1:3] != b'WS':
- raise ExtractorError(
- 'Not an SWF file; header is %r' % file_contents[:3])
- if file_contents[:1] == b'C':
- content = zlib.decompress(file_contents[8:])
- else:
- raise NotImplementedError(
- 'Unsupported compression format %r' %
- file_contents[:1])
-
- # Determine number of bits in framesize rectangle
- framesize_nbits = struct.unpack('!B', content[:1])[0] >> 3
- framesize_len = (5 + 4 * framesize_nbits + 7) // 8
-
- pos = framesize_len + 2 + 2
- while pos < len(content):
- header16 = struct.unpack('<H', content[pos:pos + 2])[0]
- pos += 2
- tag_code = header16 >> 6
- tag_len = header16 & 0x3f
- if tag_len == 0x3f:
- tag_len = struct.unpack('<I', content[pos:pos + 4])[0]
- pos += 4
- assert pos + tag_len <= len(content), \
- ('Tag %d ends at %d+%d - that\'s longer than the file (%d)'
- % (tag_code, pos, tag_len, len(content)))
- yield (tag_code, content[pos:pos + tag_len])
- pos += tag_len
-
-
- class _AVMClass_Object(object):
- def __init__(self, avm_class):
- self.avm_class = avm_class
-
- def __repr__(self):
- return '%s#%x' % (self.avm_class.name, id(self))
-
-
- class _ScopeDict(dict):
- def __init__(self, avm_class):
- super(_ScopeDict, self).__init__()
- self.avm_class = avm_class
-
- def __repr__(self):
- return '%s__Scope(%s)' % (
- self.avm_class.name,
- super(_ScopeDict, self).__repr__())
-
-
- class _AVMClass(object):
- def __init__(self, name_idx, name):
- self.name_idx = name_idx
- self.name = name
- self.method_names = {}
- self.method_idxs = {}
- self.methods = {}
- self.method_pyfunctions = {}
-
- self.variables = _ScopeDict(self)
-
- def make_object(self):
- return _AVMClass_Object(self)
-
- def __repr__(self):
- return '_AVMClass(%s)' % (self.name)
-
- def register_methods(self, methods):
- self.method_names.update(methods.items())
- self.method_idxs.update(dict(
- (idx, name)
- for name, idx in methods.items()))
-
-
- class _Multiname(object):
- def __init__(self, kind):
- self.kind = kind
-
- def __repr__(self):
- return '[MULTINAME kind: 0x%x]' % self.kind
-
-
- def _read_int(reader):
- res = 0
- shift = 0
- for _ in range(5):
- buf = reader.read(1)
- assert len(buf) == 1
- b = struct.unpack('<B', buf)[0]
- res = res | ((b & 0x7f) << shift)
- if b & 0x80 == 0:
- break
- shift += 7
- return res
-
-
- def _u30(reader):
- res = _read_int(reader)
- assert res & 0xf0000000 == 0
- return res
- u32 = _read_int
-
-
- def _s32(reader):
- v = _read_int(reader)
- if v & 0x80000000 != 0:
- v = - ((v ^ 0xffffffff) + 1)
- return v
-
-
- def _s24(reader):
- bs = reader.read(3)
- assert len(bs) == 3
- last_byte = b'\xff' if (ord(bs[2:3]) >= 0x80) else b'\x00'
- return struct.unpack('<i', bs + last_byte)[0]
-
-
- def _read_string(reader):
- slen = _u30(reader)
- resb = reader.read(slen)
- assert len(resb) == slen
- return resb.decode('utf-8')
-
-
- def _read_bytes(count, reader):
- assert count >= 0
- resb = reader.read(count)
- assert len(resb) == count
- return resb
-
-
- def _read_byte(reader):
- resb = _read_bytes(1, reader=reader)
- res = struct.unpack('<B', resb)[0]
- return res
-
-
- class SWFInterpreter(object):
- def __init__(self, file_contents):
- code_tag = next(tag
- for tag_code, tag in _extract_tags(file_contents)
- if tag_code == 82)
- p = code_tag.index(b'\0', 4) + 1
- code_reader = io.BytesIO(code_tag[p:])
-
- # Parse ABC (AVM2 ByteCode)
-
- # Define a couple convenience methods
- u30 = lambda *args: _u30(*args, reader=code_reader)
- s32 = lambda *args: _s32(*args, reader=code_reader)
- u32 = lambda *args: _u32(*args, reader=code_reader)
- read_bytes = lambda *args: _read_bytes(*args, reader=code_reader)
- read_byte = lambda *args: _read_byte(*args, reader=code_reader)
-
- # minor_version + major_version
- read_bytes(2 + 2)
-
- # Constant pool
- int_count = u30()
- for _c in range(1, int_count):
- s32()
- uint_count = u30()
- for _c in range(1, uint_count):
- u32()
- double_count = u30()
- read_bytes(max(0, (double_count - 1)) * 8)
- string_count = u30()
- self.constant_strings = ['']
- for _c in range(1, string_count):
- s = _read_string(code_reader)
- self.constant_strings.append(s)
- namespace_count = u30()
- for _c in range(1, namespace_count):
- read_bytes(1) # kind
- u30() # name
- ns_set_count = u30()
- for _c in range(1, ns_set_count):
- count = u30()
- for _c2 in range(count):
- u30()
- multiname_count = u30()
- MULTINAME_SIZES = {
- 0x07: 2, # QName
- 0x0d: 2, # QNameA
- 0x0f: 1, # RTQName
- 0x10: 1, # RTQNameA
- 0x11: 0, # RTQNameL
- 0x12: 0, # RTQNameLA
- 0x09: 2, # Multiname
- 0x0e: 2, # MultinameA
- 0x1b: 1, # MultinameL
- 0x1c: 1, # MultinameLA
- }
- self.multinames = ['']
- for _c in range(1, multiname_count):
- kind = u30()
- assert kind in MULTINAME_SIZES, 'Invalid multiname kind %r' % kind
- if kind == 0x07:
- u30() # namespace_idx
- name_idx = u30()
- self.multinames.append(self.constant_strings[name_idx])
- else:
- self.multinames.append(_Multiname(kind))
- for _c2 in range(MULTINAME_SIZES[kind]):
- u30()
-
- # Methods
- method_count = u30()
- MethodInfo = collections.namedtuple(
- 'MethodInfo',
- ['NEED_ARGUMENTS', 'NEED_REST'])
- method_infos = []
- for method_id in range(method_count):
- param_count = u30()
- u30() # return type
- for _ in range(param_count):
- u30() # param type
- u30() # name index (always 0 for youtube)
- flags = read_byte()
- if flags & 0x08 != 0:
- # Options present
- option_count = u30()
- for c in range(option_count):
- u30() # val
- read_bytes(1) # kind
- if flags & 0x80 != 0:
- # Param names present
- for _ in range(param_count):
- u30() # param name
- mi = MethodInfo(flags & 0x01 != 0, flags & 0x04 != 0)
- method_infos.append(mi)
-
- # Metadata
- metadata_count = u30()
- for _c in range(metadata_count):
- u30() # name
- item_count = u30()
- for _c2 in range(item_count):
- u30() # key
- u30() # value
-
- def parse_traits_info():
- trait_name_idx = u30()
- kind_full = read_byte()
- kind = kind_full & 0x0f
- attrs = kind_full >> 4
- methods = {}
- if kind in [0x00, 0x06]: # Slot or Const
- u30() # Slot id
- u30() # type_name_idx
- vindex = u30()
- if vindex != 0:
- read_byte() # vkind
- elif kind in [0x01, 0x02, 0x03]: # Method / Getter / Setter
- u30() # disp_id
- method_idx = u30()
- methods[self.multinames[trait_name_idx]] = method_idx
- elif kind == 0x04: # Class
- u30() # slot_id
- u30() # classi
- elif kind == 0x05: # Function
- u30() # slot_id
- function_idx = u30()
- methods[function_idx] = self.multinames[trait_name_idx]
- else:
- raise ExtractorError('Unsupported trait kind %d' % kind)
-
- if attrs & 0x4 != 0: # Metadata present
- metadata_count = u30()
- for _c3 in range(metadata_count):
- u30() # metadata index
-
- return methods
-
- # Classes
- class_count = u30()
- classes = []
- for class_id in range(class_count):
- name_idx = u30()
-
- cname = self.multinames[name_idx]
- avm_class = _AVMClass(name_idx, cname)
- classes.append(avm_class)
-
- u30() # super_name idx
- flags = read_byte()
- if flags & 0x08 != 0: # Protected namespace is present
- u30() # protected_ns_idx
- intrf_count = u30()
- for _c2 in range(intrf_count):
- u30()
- u30() # iinit
- trait_count = u30()
- for _c2 in range(trait_count):
- trait_methods = parse_traits_info()
- avm_class.register_methods(trait_methods)
-
- assert len(classes) == class_count
- self._classes_by_name = dict((c.name, c) for c in classes)
-
- for avm_class in classes:
- u30() # cinit
- trait_count = u30()
- for _c2 in range(trait_count):
- trait_methods = parse_traits_info()
- avm_class.register_methods(trait_methods)
-
- # Scripts
- script_count = u30()
- for _c in range(script_count):
- u30() # init
- trait_count = u30()
- for _c2 in range(trait_count):
- parse_traits_info()
-
- # Method bodies
- method_body_count = u30()
- Method = collections.namedtuple('Method', ['code', 'local_count'])
- for _c in range(method_body_count):
- method_idx = u30()
- u30() # max_stack
- local_count = u30()
- u30() # init_scope_depth
- u30() # max_scope_depth
- code_length = u30()
- code = read_bytes(code_length)
- for avm_class in classes:
- if method_idx in avm_class.method_idxs:
- m = Method(code, local_count)
- avm_class.methods[avm_class.method_idxs[method_idx]] = m
- exception_count = u30()
- for _c2 in range(exception_count):
- u30() # from
- u30() # to
- u30() # target
- u30() # exc_type
- u30() # var_name
- trait_count = u30()
- for _c2 in range(trait_count):
- parse_traits_info()
-
- assert p + code_reader.tell() == len(code_tag)
-
- def extract_class(self, class_name):
- try:
- return self._classes_by_name[class_name]
- except KeyError:
- raise ExtractorError('Class %r not found' % class_name)
-
- def extract_function(self, avm_class, func_name):
- if func_name in avm_class.method_pyfunctions:
- return avm_class.method_pyfunctions[func_name]
- if func_name in self._classes_by_name:
- return self._classes_by_name[func_name].make_object()
- if func_name not in avm_class.methods:
- raise ExtractorError('Cannot find function %s.%s' % (
- avm_class.name, func_name))
- m = avm_class.methods[func_name]
-
- def resfunc(args):
- # Helper functions
- coder = io.BytesIO(m.code)
- s24 = lambda: _s24(coder)
- u30 = lambda: _u30(coder)
-
- registers = [avm_class.variables] + list(args) + [None] * m.local_count
- stack = []
- scopes = collections.deque([
- self._classes_by_name, avm_class.variables])
- while True:
- opcode = _read_byte(coder)
- if opcode == 17: # iftrue
- offset = s24()
- value = stack.pop()
- if value:
- coder.seek(coder.tell() + offset)
- elif opcode == 18: # iffalse
- offset = s24()
- value = stack.pop()
- if not value:
- coder.seek(coder.tell() + offset)
- elif opcode == 36: # pushbyte
- v = _read_byte(coder)
- stack.append(v)
- elif opcode == 42: # dup
- value = stack[-1]
- stack.append(value)
- elif opcode == 44: # pushstring
- idx = u30()
- stack.append(self.constant_strings[idx])
- elif opcode == 48: # pushscope
- new_scope = stack.pop()
- scopes.append(new_scope)
- elif opcode == 66: # construct
- arg_count = u30()
- args = list(reversed(
- [stack.pop() for _ in range(arg_count)]))
- obj = stack.pop()
- res = obj.avm_class.make_object()
- stack.append(res)
- elif opcode == 70: # callproperty
- index = u30()
- mname = self.multinames[index]
- arg_count = u30()
- args = list(reversed(
- [stack.pop() for _ in range(arg_count)]))
- obj = stack.pop()
-
- if isinstance(obj, _AVMClass_Object):
- func = self.extract_function(obj.avm_class, mname)
- res = func(args)
- stack.append(res)
- continue
- elif isinstance(obj, _ScopeDict):
- if mname in obj.avm_class.method_names:
- func = self.extract_function(obj.avm_class, mname)
- res = func(args)
- else:
- res = obj[mname]
- stack.append(res)
- continue
- elif isinstance(obj, compat_str):
- if mname == 'split':
- assert len(args) == 1
- assert isinstance(args[0], compat_str)
- if args[0] == '':
- res = list(obj)
- else:
- res = obj.split(args[0])
- stack.append(res)
- continue
- elif isinstance(obj, list):
- if mname == 'slice':
- assert len(args) == 1
- assert isinstance(args[0], int)
- res = obj[args[0]:]
- stack.append(res)
- continue
- elif mname == 'join':
- assert len(args) == 1
- assert isinstance(args[0], compat_str)
- res = args[0].join(obj)
- stack.append(res)
- continue
- raise NotImplementedError(
- 'Unsupported property %r on %r'
- % (mname, obj))
- elif opcode == 72: # returnvalue
- res = stack.pop()
- return res
- elif opcode == 74: # constructproperty
- index = u30()
- arg_count = u30()
- args = list(reversed(
- [stack.pop() for _ in range(arg_count)]))
- obj = stack.pop()
-
- mname = self.multinames[index]
- assert isinstance(obj, _AVMClass)
- construct_method = self.extract_function(
- obj, mname)
- # We do not actually call the constructor for now;
- # we just pretend it does nothing
- stack.append(obj.make_object())
- elif opcode == 79: # callpropvoid
- index = u30()
- mname = self.multinames[index]
- arg_count = u30()
- args = list(reversed(
- [stack.pop() for _ in range(arg_count)]))
- obj = stack.pop()
- if mname == 'reverse':
- assert isinstance(obj, list)
- obj.reverse()
- else:
- raise NotImplementedError(
- 'Unsupported (void) property %r on %r'
- % (mname, obj))
- elif opcode == 86: # newarray
- arg_count = u30()
- arr = []
- for i in range(arg_count):
- arr.append(stack.pop())
- arr = arr[::-1]
- stack.append(arr)
- elif opcode == 93: # findpropstrict
- index = u30()
- mname = self.multinames[index]
- for s in reversed(scopes):
- if mname in s:
- res = s
- break
- else:
- res = scopes[0]
- stack.append(res[mname])
- elif opcode == 94: # findproperty
- index = u30()
- mname = self.multinames[index]
- for s in reversed(scopes):
- if mname in s:
- res = s
- break
- else:
- res = avm_class.variables
- stack.append(res)
- elif opcode == 96: # getlex
- index = u30()
- mname = self.multinames[index]
- for s in reversed(scopes):
- if mname in s:
- scope = s
- break
- else:
- scope = avm_class.variables
- # I cannot find where static variables are initialized
- # so let's just return None
- res = scope.get(mname)
- stack.append(res)
- elif opcode == 97: # setproperty
- index = u30()
- value = stack.pop()
- idx = self.multinames[index]
- if isinstance(idx, _Multiname):
- idx = stack.pop()
- obj = stack.pop()
- obj[idx] = value
- elif opcode == 98: # getlocal
- index = u30()
- stack.append(registers[index])
- elif opcode == 99: # setlocal
- index = u30()
- value = stack.pop()
- registers[index] = value
- elif opcode == 102: # getproperty
- index = u30()
- pname = self.multinames[index]
- if pname == 'length':
- obj = stack.pop()
- assert isinstance(obj, list)
- stack.append(len(obj))
- else: # Assume attribute access
- idx = stack.pop()
- assert isinstance(idx, int)
- obj = stack.pop()
- assert isinstance(obj, list)
- stack.append(obj[idx])
- elif opcode == 115: # convert_
- value = stack.pop()
- intvalue = int(value)
- stack.append(intvalue)
- elif opcode == 128: # coerce
- u30()
- elif opcode == 133: # coerce_s
- assert isinstance(stack[-1], (type(None), compat_str))
- elif opcode == 160: # add
- value2 = stack.pop()
- value1 = stack.pop()
- res = value1 + value2
- stack.append(res)
- elif opcode == 161: # subtract
- value2 = stack.pop()
- value1 = stack.pop()
- res = value1 - value2
- stack.append(res)
- elif opcode == 164: # modulo
- value2 = stack.pop()
- value1 = stack.pop()
- res = value1 % value2
- stack.append(res)
- elif opcode == 175: # greaterequals
- value2 = stack.pop()
- value1 = stack.pop()
- result = value1 >= value2
- stack.append(result)
- elif opcode == 208: # getlocal_0
- stack.append(registers[0])
- elif opcode == 209: # getlocal_1
- stack.append(registers[1])
- elif opcode == 210: # getlocal_2
- stack.append(registers[2])
- elif opcode == 211: # getlocal_3
- stack.append(registers[3])
- elif opcode == 212: # setlocal_0
- registers[0] = stack.pop()
- elif opcode == 213: # setlocal_1
- registers[1] = stack.pop()
- elif opcode == 214: # setlocal_2
- registers[2] = stack.pop()
- elif opcode == 215: # setlocal_3
- registers[3] = stack.pop()
- else:
- raise NotImplementedError(
- 'Unsupported opcode %d' % opcode)
-
- avm_class.method_pyfunctions[func_name] = resfunc
- return resfunc
-
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