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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
# -*- coding: utf-8 -*-
# auth.py
# Copyright (C) 2013 LEAP
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
Twisted http token auth.
"""
import binascii
import time
from hashlib import sha512
from zope.interface import implementer
from twisted.cred import error
from twisted.cred.checkers import ICredentialsChecker
from twisted.cred.credentials import IUsernamePassword
from twisted.cred.credentials import UsernamePassword
from twisted.cred.portal import IRealm
from twisted.cred.portal import Portal
from twisted.internet import defer
from twisted.web.iweb import ICredentialFactory
from twisted.web.resource import IResource
from leap.soledad.common.couch import couch_server
from ._resource import SoledadResource
from ._config import get_config
@implementer(IRealm)
class SoledadRealm(object):
def __init__(self, conf=None, sync_pool=None):
if not conf:
conf = get_config()
self._conf = conf
self._sync_pool = sync_pool
def requestAvatar(self, avatarId, mind, *interfaces):
if IResource in interfaces:
enable_blobs = self._conf['blobs']
resource = SoledadResource(
enable_blobs=enable_blobs,
sync_pool=self._sync_pool)
return (IResource, resource, lambda: None)
raise NotImplementedError()
@implementer(ICredentialsChecker)
class TokenChecker(object):
credentialInterfaces = [IUsernamePassword]
TOKENS_DB_PREFIX = "tokens_"
TOKENS_DB_EXPIRE = 30 * 24 * 3600 # 30 days in seconds
TOKENS_TYPE_KEY = "type"
TOKENS_TYPE_DEF = "Token"
TOKENS_USER_ID_KEY = "user_id"
def __init__(self, server=None):
if server is None:
config = get_config()
couch_url = config['couch_url']
server = couch_server(couch_url)
self._server = server
self._dbs = {}
def _tokens_dbname(self):
# the tokens db rotates every 30 days, and the current db name is
# "tokens_NNN", where NNN is the number of seconds since epoch
# divide dby the rotate period in seconds. When rotating, old and
# new tokens db coexist during a certain window of time and valid
# tokens are replicated from the old db to the new one. See:
# https://leap.se/code/issues/6785
dbname = self.TOKENS_DB_PREFIX + \
str(int(time.time() / self.TOKENS_DB_EXPIRE))
return dbname
def _tokens_db(self):
dbname = self._tokens_dbname()
with self._server as server:
db = server[dbname]
return db
def requestAvatarId(self, credentials):
uuid = credentials.username
token = credentials.password
# lookup key is a hash of the token to prevent timing attacks.
db = self._tokens_db()
token = db.get(sha512(token).hexdigest())
if token is None:
return defer.fail(error.UnauthorizedLogin())
# we compare uuid hashes to avoid possible timing attacks that
# might exploit python's builtin comparison operator behaviour,
# which fails immediatelly when non-matching bytes are found.
couch_uuid_hash = sha512(token[self.TOKENS_USER_ID_KEY]).digest()
req_uuid_hash = sha512(uuid).digest()
if token[self.TOKENS_TYPE_KEY] != self.TOKENS_TYPE_DEF \
or couch_uuid_hash != req_uuid_hash:
return defer.fail(error.UnauthorizedLogin())
return defer.succeed(uuid)
@implementer(ICredentialFactory)
class TokenCredentialFactory(object):
scheme = 'token'
def getChallenge(self, request):
return {}
def decode(self, response, request):
try:
creds = binascii.a2b_base64(response + b'===')
except binascii.Error:
raise error.LoginFailed('Invalid credentials')
creds = creds.split(b':', 1)
if len(creds) == 2:
return UsernamePassword(*creds)
else:
raise error.LoginFailed('Invalid credentials')
def get_portal(sync_pool=None):
realm = SoledadRealm(sync_pool=sync_pool)
checker = TokenChecker()
return Portal(realm, [checker])
credentialFactory = TokenCredentialFactory()
|
