/usr/lib/python3/dist-packages/pgpdump/data.py is in python3-pgpdump 1.5-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 | from base64 import b64decode
from .packet import construct_packet
from .utils import PgpdumpException, crc24
class BinaryData(object):
'''The base object used for extracting PGP data packets. This expects fully
binary data as input; such as that read from a .sig or .gpg file.'''
binary_tag_flag = 0x80
def __init__(self, data):
if not data:
raise PgpdumpException("no data to parse")
if len(data) <= 1:
raise PgpdumpException("data too short")
data = bytearray(data)
# 7th bit of the first byte must be a 1
if not bool(data[0] & self.binary_tag_flag):
raise PgpdumpException("incorrect binary data")
self.data = data
self.length = len(data)
def packets(self):
'''A generator function returning PGP data packets.'''
offset = 0
while offset < self.length:
total_length, packet = construct_packet(self.data, offset)
offset += total_length
yield packet
def __repr__(self):
return "<%s: length %d>" % (
self.__class__.__name__, self.length)
class AsciiData(BinaryData):
'''A wrapper class that supports ASCII-armored input. It searches for the
first PGP magic header and extracts the data contained within.'''
def __init__(self, data):
self.original_data = data
data = self.strip_magic(data)
data, known_crc = self.split_data_crc(data)
data = bytearray(b64decode(data))
if known_crc:
# verify it if we could find it
actual_crc = crc24(data)
if known_crc != actual_crc:
raise PgpdumpException(
"CRC failure: known 0x%x, actual 0x%x" % (
known_crc, actual_crc))
super(AsciiData, self).__init__(data)
@staticmethod
def strip_magic(data):
'''Strip away the '-----BEGIN PGP SIGNATURE-----' and related cruft so
we can safely base64 decode the remainder.'''
idx = 0
magic = b'-----BEGIN PGP '
ignore = b'-----BEGIN PGP SIGNED '
# find our magic string, skiping our ignored string
while True:
idx = data.find(magic, idx)
if data[idx:len(ignore)] != ignore:
break
idx += 1
if idx >= 0:
# find the start of the actual data. it always immediately follows
# a blank line, meaning headers are done.
nl_idx = data.find(b'\n\n', idx)
if nl_idx < 0:
nl_idx = data.find(b'\r\n\r\n', idx)
if nl_idx < 0:
raise PgpdumpException(
"found magic, could not find start of data")
# now find the end of the data.
end_idx = data.find(b'-----', nl_idx)
if end_idx:
data = data[nl_idx:end_idx]
else:
data = data[nl_idx:]
return data
@staticmethod
def split_data_crc(data):
'''The Radix-64 format appends any CRC checksum to the end of the data
block, in the form '=alph', where there are always 4 ASCII characters
correspnding to 3 digits (24 bits). Look for this special case.'''
# don't let newlines trip us up
data = data.rstrip()
# this funkyness makes it work without changes in Py2 and Py3
if data[-5] in (b'=', ord(b'=')):
# CRC is returned without the = and converted to a decimal
crc = b64decode(data[-4:])
# same noted funkyness as above, due to bytearray implementation
crc = [ord(c) if isinstance(c, str) else c for c in crc]
crc = (crc[0] << 16) + (crc[1] << 8) + crc[2]
return (data[:-5], crc)
return (data, None)
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