Master

parse_ar.py

@@ -0,0 +1,87 @@
+import sys
+
+import os
+import sys
+
+class Chunk:
+    offset: int
+    tx_index: int
+    def __init__(self, offset, tx_index):
+        self.offset = offset
+        self.tx_index = tx_index
+
+
+def get_bitcode():
+	return [0xf73524c107000000, 0x44f258daf3f32ee8,
+		0xf4cfcee0ae056a88, 0x7a0b8e9827e5c162,
+		0x84807c35793713ad, 0x5a576ac3c8f5ffec,
+	]
+
+def normalize_offset(offset):
+	if offset & 0xfff != 0:
+		return offset - (offset & 0xfff)
+
+def decode_chunk(chunk_data, num):
+	bitcode = get_bitcode()
+	chunkfile = open('chunks/chunk_{}.dat'.format(num), 'wb')
+
+	for i in range(0, int(0x40000/0x8)):
+		dat8 = int.from_bytes(chunk_data[i*8:i*8+8], 'little')
+		res = dat8 ^ bitcode[i % 0x6]
+
+		chunkfile.write(res.to_bytes(8, 'little'))
+
+def parse(filename):
+	print('[INFO] Loading ar file {} .....'.format(filename))
+	print('[INFO] AR file size: {}'.format(os.path.getsize(filename)))
+	arfile = open(filename, 'rb')
+
+	# Read file flag 10 bytes
+	file_flag = int.from_bytes(arfile.read(10), 'little')
+	print('[INFO] file flag {}'.format(file_flag))
+	# Read file version 4 bytes
+	file_ver = int.from_bytes(arfile.read(4), 'little')
+	print('[INFO] file version {}'.format(file_ver))
+	# Read tx path 4 bytes
+	tx_path_num = int.from_bytes(arfile.read(4), 'little')
+	print('[INFO] tx path number {}'.format(hex(tx_path_num)))
+	# Read chunk number 4
+	chunk_num = int.from_bytes(arfile.read(4), 'little')
+	print('[INFO] chunk number {}'.format(hex(chunk_num)))
+	# Read offset 8
+	offset = int.from_bytes(arfile.read(8), 'little')
+	print('[INFO] weave offset {}'.format(hex(offset)))
+	# Read weave size 8
+	weave_size = int.from_bytes(arfile.read(8), 'little')
+	print('[INFO] weave size {}'.format(hex(weave_size)))
+
+	# Read tx paths
+	for i in range(0, tx_path_num):
+		tx_path = int.from_bytes(arfile.read(2), 'little')
+		print('[INFO] tx path {}'.format(tx_path))
+
+	chunks = []
+
+	# Read chunks
+	for i in range(0, chunk_num):
+		# Read chunk offset 4
+		choff = int.from_bytes(arfile.read(4), 'little')
+		# Read chunk weave offset 8
+		weave_offset = int.from_bytes(arfile.read(8), 'little')
+		# Read chunk weave size 4
+		weave_size = int.from_bytes(arfile.read(4), 'little')
+		# Read tx index	4
+		tx_index = int.from_bytes(arfile.read(4), 'little')
+
+		chunk = Chunk(choff, tx_index)
+		chunks.append(chunk)
+
+	for i,chunk in enumerate(chunks):
+		wtd = chunk.offset + (chunk.tx_index - 0x40000)
+		print('[*] Decoding chunk {} at offset {} ....'.format(i, hex(wtd)))
+
+		arfile.seek(wtd)
+		decode_chunk(arfile.read(0x40000), i)
+
+if __name__ == '__main__':
+    parse(sys.argv[1])