cZbf1SQu

1""" Flask Session Cookie Decoder/Encoder """
2__author__ = 'Wilson Sumanang, Alexandre ZANNI'
3
4# standard imports
5import sys
6import zlib
7from itsdangerous import base64_decode
8import ast
9
10# Abstract Base Classes (PEP 3119)
11if sys.version_info[0] < 3: # < 3.0
12    raise Exception('Must be using at least Python 3')
13elif sys.version_info[0] == 3 and sys.version_info[1] < 4: # >= 3.0 && < 3.4
14    from abc import ABCMeta, abstractmethod
15else: # > 3.4
16    from abc import ABC, abstractmethod
17
18# Lib for argument parsing
19import argparse
20
21# external Imports
22from flask.sessions import SecureCookieSessionInterface
23
24class MockApp(object):
25
26    def __init__(self, secret_key):
27        self.secret_key = secret_key
28
29
30if sys.version_info[0] == 3 and sys.version_info[1] < 4: # >= 3.0 && < 3.4
31    class FSCM(metaclass=ABCMeta):
32        def encode(secret_key, session_cookie_structure):
33            """ Encode a Flask session cookie """
34            try:
35                app = MockApp(secret_key)
36
37                session_cookie_structure = dict(ast.literal_eval(session_cookie_structure))
38                si = SecureCookieSessionInterface()
39                s = si.get_signing_serializer(app)
40
41                return s.dumps(session_cookie_structure)
42            except Exception as e:
43                return "[Encoding error] {}".format(e)
44                raise e
45
46
47        def decode(session_cookie_value, secret_key=None):
48            """ Decode a Flask cookie  """
49            try:
50                if(secret_key==None):
51                    compressed = False
52                    payload = session_cookie_value
53
54                    if payload.startswith('.'):
55                        compressed = True
56                        payload = payload[1:]
57
58                    data = payload.split(".")[0]
59
60                    data = base64_decode(data)
61                    if compressed:
62                        data = zlib.decompress(data)
63
64                    return data
65                else:
66                    app = MockApp(secret_key)
67
68                    si = SecureCookieSessionInterface()
69                    s = si.get_signing_serializer(app)
70
71                    return s.loads(session_cookie_value)
72            except Exception as e:
73                return "[Decoding error] {}".format(e)
74                raise e
75else: # > 3.4
76    class FSCM(ABC):
77        def encode(secret_key, session_cookie_structure):
78            """ Encode a Flask session cookie """
79            try:
80                app = MockApp(secret_key)
81
82                session_cookie_structure = dict(ast.literal_eval(session_cookie_structure))
83                si = SecureCookieSessionInterface()
84                s = si.get_signing_serializer(app)
85
86                return s.dumps(session_cookie_structure)
87            except Exception as e:
88                return "[Encoding error] {}".format(e)
89                raise e
90
91
92        def decode(session_cookie_value, secret_key=None):
93            """ Decode a Flask cookie  """
94            try:
95                if(secret_key==None):
96                    compressed = False
97                    payload = session_cookie_value
98
99                    if payload.startswith('.'):
100                        compressed = True
101                        payload = payload[1:]
102
103                    data = payload.split(".")[0]
104
105                    data = base64_decode(data)
106                    if compressed:
107                        data = zlib.decompress(data)
108
109                    return data
110                else:
111                    app = MockApp(secret_key)
112
113                    si = SecureCookieSessionInterface()
114                    s = si.get_signing_serializer(app)
115
116                    return s.loads(session_cookie_value)
117            except Exception as e:
118                return "[Decoding error] {}".format(e)
119                raise e
120
121
122if __name__ == "__main__":
123    # Args are only relevant for __main__ usage
124    
125    ## Description for help
126    parser = argparse.ArgumentParser(
127                description='Flask Session Cookie Decoder/Encoder',
128                epilog="Author : Wilson Sumanang, Alexandre ZANNI")
129
130    ## prepare sub commands
131    subparsers = parser.add_subparsers(help='sub-command help', dest='subcommand')
132
133    ## create the parser for the encode command
134    parser_encode = subparsers.add_parser('encode', help='encode')
135    parser_encode.add_argument('-s', '--secret-key', metavar='<string>',
136                                help='Secret key', required=True)
137    parser_encode.add_argument('-t', '--cookie-structure', metavar='<string>',
138                                help='Session cookie structure', required=True)
139
140    ## create the parser for the decode command
141    parser_decode = subparsers.add_parser('decode', help='decode')
142    parser_decode.add_argument('-s', '--secret-key', metavar='<string>',
143                                help='Secret key', required=False)
144    parser_decode.add_argument('-c', '--cookie-value', metavar='<string>',
145                                help='Session cookie value', required=True)
146
147    ## get args
148    args = parser.parse_args()
149
150    ## find the option chosen
151    if(args.subcommand == 'encode'):
152        if(args.secret_key is not None and args.cookie_structure is not None):
153            print(FSCM.encode(args.secret_key, args.cookie_structure))
154    elif(args.subcommand == 'decode'):
155        if(args.secret_key is not None and args.cookie_value is not None):
156            print(FSCM.decode(args.cookie_value,args.secret_key))
157        elif(args.cookie_value is not None):
158            print(FSCM.decode(args.cookie_value))