def _yenc_decode(text_lines):
RE_YENC_BEGIN = re.compile('=ybegin .*name=(.+)')
RE_YENC_PART = re.compile('=ypart .*begin=(.+) ')
yenc_decoder = None
content_file_name = None
content_file_offset = 0
for text_line in text_lines:
if not yenc_decoder:
match_result = RE_YENC_BEGIN.match(text_line)
if match_result:
content_file_name = match_result.group(1)
yenc_decoder = yenc.Decoder()
continue
if text_line.startswith('=ypart '):
content_file_offset = int(
RE_YENC_PART.match(text_line).group(1)) - 1
continue
if text_line.startswith('=yend '):
break
yenc_decoder.feed(text_line)
return yenc_decoder.getDecoded()
def start(file_name, output):
data = ''
hexdata = ''
decoder = yenc.Decoder()
cap = rdpcap(file_name)
packet_len = len(cap)
num_written = 0
for i in cap:
# If the ICMP packet is of type = request
if i[ICMP].type == 8:
try:
if output in ['a', 'h']:
# Get the raw payload from the ICMP packet. This i[Raw] returns the hex encoded payload as ascii, , hence we have to use '-o h' option to print literal hex values
data = data + str(i[Raw])
if output == 'y':
decoder.feed(str(i[Raw]))
num_written = num_written + 1
except Exception as e:
print("Exception: {}".format(e))
continue
if output == 'a':
# Print raw payload
print(data, end="")
if output == 'h':
# Get raw hex characters instead of printable ascii like how the '-o a' option returns becuase of i[Raw] returning ascii encoded characters
print(str(binascii.hexlify(data)), end="")
if output == 'y':
print(decoder.getDecoded(), end="")
print("\nInput File : {}".format(file_name), file=sys.stderr)
print("Output Type : {}".format(output), file=sys.stderr)
print("Packet Length : {}".format(packet_len), file=sys.stderr)
print("Number of payload packets written : {}\n".format(num_written),
file=sys.stderr)
exit()
def _testEncoderDecoder(self, filename):
file_data, crc = self._readFile(filename)
file_out = open(filename + '.out', 'wb')
encoder = yenc.Encoder(file_out)
with open(filename, 'rb') as file_in:
data = file_in.read(BLOCK_SIZE)
while len(data):
encoder.feed(data)
data = file_in.read(BLOCK_SIZE)
encoder.terminate()
logging.info("orig: %s enc: %s" % (crc, encoder.getCrc32()))
self.assertEqual(crc, encoder.getCrc32())
# deleting forces files to be flushed
del encoder
file_out = open(filename + '.dec', 'wb')
decoder = yenc.Decoder(file_out)
with open(filename + '.out', 'rb') as file_in:
data = file_in.read(BLOCK_SIZE)
while len(data) > 0:
decoder.feed(data)
data = file_in.read(BLOCK_SIZE)
decoder.flush()
logging.info("orig: %s dec: %s" % (crc, decoder.getCrc32()))
self.assertEqual(crc, decoder.getCrc32())
# deleting forces files to be flushed
# if __del__ is not called further tests are going to fail
del decoder
data_dec, crc_dec = self._readFile(filename + '.dec')
self.assertEqual(file_data, data_dec)
self.assertEqual(crc, crc_dec)
def reset(self):
self._state = YencLineHandler.STATE_WAITING
self._decoder = yenc.Decoder()
def main():
head_crc = trail_crc = None
if len(sys.argv) > 1:
file_in = open(sys.argv[1], "rb")
else:
try: # Python 3
file_in = sys.stdin.detach()
except: # Python < 3
file_in = sys.stdin
sys.stdin = None
with file_in:
while True:
line = file_in.readline()
if line.startswith(b"=ybegin "):
try:
name, size = NAME_RE.match(line).group(1), int(
SIZE_RE.match(line).group(1))
m_obj = CRC32_RE.match(line)
if m_obj:
head_crc = m_obj.group(1)
except re.error:
sys.stderr.write(
"err-critical: malformed =ybegin header\n")
sys.exit(1)
break
elif not line:
sys.stderr.write(
"err-critical: no valid =ybegin header found\n")
sys.exit(1)
file_out = open(name, "wb")
dec = yenc.Decoder(file_out)
trailer = None
garbage = False
while True:
data = file_in.readline()
if data.startswith(b"=yend"):
trailer = data
break
elif dec.getSize() >= size:
garbage = True
else:
dec.feed(data)
dec.flush()
if trailer:
try:
size = int(SIZE_RE.match(trailer).group(1))
m_obj = CRC32_RE.search(trailer)
if m_obj:
trail_crc = m_obj.group(1)
except re.error:
sys.stderr.write("err: malformed =yend trailer\n")
else:
sys.stderr.write("warning: couldn't find =yend trailer\n")
if garbage:
sys.stderr.write("warning: garbage before =yend trailer\n")
if head_crc:
tmp_crc = head_crc.decode("ascii").lower()
elif trail_crc:
tmp_crc = trail_crc.decode("ascii").lower()
else:
sys.exit(0)
# sys.stderr.write("comparing\n")
if tmp_crc != dec.getCrc32():
sys.stderr.write("err: header: %s dec: %s CRC32 mismatch\n" %
(tmp_crc, dec.getCrc32()))
sys.exit(1)
else:
sys.exit(0)
def testDecodeFlushInMemory(self):
decoder = yenc.Decoder()
self.assertRaises(ValueError, decoder.flush)
def testDecoderCloseInMemory(self):
decoder = yenc.Decoder()
self.assertRaises(ValueError, decoder.close)
def testDecodeInMemory(self):
decoder = yenc.Decoder()
decoder.feed(b'r\x8f\x96\x96\x99J\xa1\x99\x9c\x96\x8eK')
self.assertEqual(b"Hello world!", decoder.getDecoded())
self.assertEqual(decoder.getCrc32(),
"%08x" % (crc32(b"Hello world!") & 0xffffffff))
def testDecoderClose(self):
decoder = yenc.Decoder(open('afile.out', 'wb'))
decoder.feed(b'some data')
decoder.close()
self.assertFalse(decoder._output_file)
def parse_data(data, my_decode_flag, my_caesar_flag):
my_answers = list()
if my_decode_flag is True:
for name in ('hex_codec', 'base64_codec', 'rot_13', 'utf_8',
'utf_16_be', 'utf_16_le', 'bz2', 'zip', 'idna', 'palmos',
'punycode', 'quopri_codec', 'utf_7'):
try:
result = data.decode(name)
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'base32'
try:
result = base64.b32decode(data)
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'uuencode'
try:
result = binascii.a2b_uu(data)
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'quotable'
try:
result = binascii.a2b_qp(data)
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'binhex4'
try:
result = binascii.rledecode_hqx(binascii.a2b_hqx(data))
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'yenc'
try:
decoder = yenc.Decoder()
decoder.feed(data)
result = decoder.getDecoded()
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
else:
for name in ('hex_codec', 'base64_codec', 'rot_13', 'utf_8',
'utf_16_be', 'utf_16_le', 'bz2', 'zip', 'idna', 'palmos',
'punycode', 'quopri_codec', 'utf_7'):
try:
result = data.encode(name)
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'base32'
try:
result = base64.b32encode(data)
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'uuencode'
try:
result = binascii.b2a_uu(data)
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'quotable'
try:
result = binascii.b2a_qp(data)
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'binhex4'
try:
result = binascii.b2a_hqx(binascii.rlecode_hqx(data))
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
name = 'yenc'
try:
encoder = yenc.Encoder()
encoder.feed(data)
result = encoder.getEncoded()
if verbose_flag:
print "%s succeeded" % name
my_answers.append([name, repr(result)])
except Exception as ex:
if verbose_flag:
print "%s FAILED: %s" % (name, ex)
if my_caesar_flag:
for i in range(1, 256):
my_answers.append([
"Caesar_%d" % i,
repr(''.join([chr((ord(c) + i) % 256) for c in data]))
])
my_answers.append([
"xor_%d" % i,
repr(''.join([chr((ord(c) ^ i) % 256) for c in data]))
])
return my_answers