1# -*- coding: utf-8 -*-
2"""
3oauthlib.oauth1.rfc5849.endpoints.request_token
4~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5
6This module is an implementation of the request token provider logic of
7OAuth 1.0 RFC 5849. It validates the correctness of request token requests,
8creates and persists tokens as well as create the proper response to be
9returned to the client.
10"""
11import logging
12
13from oauthlib.common import urlencode
14
15from .. import errors
16from .base import BaseEndpoint
17
18log = logging.getLogger(__name__)
19
20
21class RequestTokenEndpoint(BaseEndpoint):
22
23 """An endpoint responsible for providing OAuth 1 request tokens.
24
25 Typical use is to instantiate with a request validator and invoke the
26 ``create_request_token_response`` from a view function. The tuple returned
27 has all information necessary (body, status, headers) to quickly form
28 and return a proper response. See :doc:`/oauth1/validator` for details on which
29 validator methods to implement for this endpoint.
30 """
31
32 def create_request_token(self, request, credentials):
33 """Create and save a new request token.
34
35 :param request: OAuthlib request.
36 :type request: oauthlib.common.Request
37 :param credentials: A dict of extra token credentials.
38 :returns: The token as an urlencoded string.
39 """
40 token = {
41 'oauth_token': self.token_generator(),
42 'oauth_token_secret': self.token_generator(),
43 'oauth_callback_confirmed': 'true'
44 }
45 token.update(credentials)
46 self.request_validator.save_request_token(token, request)
47 return urlencode(token.items())
48
49 def create_request_token_response(self, uri, http_method='GET', body=None,
50 headers=None, credentials=None):
51 """Create a request token response, with a new request token if valid.
52
53 :param uri: The full URI of the token request.
54 :param http_method: A valid HTTP verb, i.e. GET, POST, PUT, HEAD, etc.
55 :param body: The request body as a string.
56 :param headers: The request headers as a dict.
57 :param credentials: A list of extra credentials to include in the token.
58 :returns: A tuple of 3 elements.
59 1. A dict of headers to set on the response.
60 2. The response body as a string.
61 3. The response status code as an integer.
62
63 An example of a valid request::
64
65 >>> from your_validator import your_validator
66 >>> from oauthlib.oauth1 import RequestTokenEndpoint
67 >>> endpoint = RequestTokenEndpoint(your_validator)
68 >>> h, b, s = endpoint.create_request_token_response(
69 ... 'https://your.provider/request_token?foo=bar',
70 ... headers={
71 ... 'Authorization': 'OAuth realm=movies user, oauth_....'
72 ... },
73 ... credentials={
74 ... 'my_specific': 'argument',
75 ... })
76 >>> h
77 {'Content-Type': 'application/x-www-form-urlencoded'}
78 >>> b
79 'oauth_token=lsdkfol23w54jlksdef&oauth_token_secret=qwe089234lkjsdf&oauth_callback_confirmed=true&my_specific=argument'
80 >>> s
81 200
82
83 An response to invalid request would have a different body and status::
84
85 >>> b
86 'error=invalid_request&description=missing+callback+uri'
87 >>> s
88 400
89
90 The same goes for an an unauthorized request:
91
92 >>> b
93 ''
94 >>> s
95 401
96 """
97 resp_headers = {'Content-Type': 'application/x-www-form-urlencoded'}
98 try:
99 request = self._create_request(uri, http_method, body, headers)
100 valid, processed_request = self.validate_request_token_request(
101 request)
102 if valid:
103 token = self.create_request_token(request, credentials or {})
104 return resp_headers, token, 200
105 else:
106 return {}, None, 401
107 except errors.OAuth1Error as e:
108 return resp_headers, e.urlencoded, e.status_code
109
110 def validate_request_token_request(self, request):
111 """Validate a request token request.
112
113 :param request: OAuthlib request.
114 :type request: oauthlib.common.Request
115 :raises: OAuth1Error if the request is invalid.
116 :returns: A tuple of 2 elements.
117 1. The validation result (True or False).
118 2. The request object.
119 """
120 self._check_transport_security(request)
121 self._check_mandatory_parameters(request)
122
123 if request.realm:
124 request.realms = request.realm.split(' ')
125 else:
126 request.realms = self.request_validator.get_default_realms(
127 request.client_key, request)
128 if not self.request_validator.check_realms(request.realms):
129 raise errors.InvalidRequestError(
130 description='Invalid realm {}. Allowed are {!r}.'.format(
131 request.realms, self.request_validator.realms))
132
133 if not request.redirect_uri:
134 raise errors.InvalidRequestError(
135 description='Missing callback URI.')
136
137 if not self.request_validator.validate_timestamp_and_nonce(
138 request.client_key, request.timestamp, request.nonce, request,
139 request_token=request.resource_owner_key):
140 return False, request
141
142 # The server SHOULD return a 401 (Unauthorized) status code when
143 # receiving a request with invalid client credentials.
144 # Note: This is postponed in order to avoid timing attacks, instead
145 # a dummy client is assigned and used to maintain near constant
146 # time request verification.
147 #
148 # Note that early exit would enable client enumeration
149 valid_client = self.request_validator.validate_client_key(
150 request.client_key, request)
151 if not valid_client:
152 request.client_key = self.request_validator.dummy_client
153
154 # Note that `realm`_ is only used in authorization headers and how
155 # it should be interpreted is not included in the OAuth spec.
156 # However they could be seen as a scope or realm to which the
157 # client has access and as such every client should be checked
158 # to ensure it is authorized access to that scope or realm.
159 # .. _`realm`: https://tools.ietf.org/html/rfc2617#section-1.2
160 #
161 # Note that early exit would enable client realm access enumeration.
162 #
163 # The require_realm indicates this is the first step in the OAuth
164 # workflow where a client requests access to a specific realm.
165 # This first step (obtaining request token) need not require a realm
166 # and can then be identified by checking the require_resource_owner
167 # flag and absence of realm.
168 #
169 # Clients obtaining an access token will not supply a realm and it will
170 # not be checked. Instead the previously requested realm should be
171 # transferred from the request token to the access token.
172 #
173 # Access to protected resources will always validate the realm but note
174 # that the realm is now tied to the access token and not provided by
175 # the client.
176 valid_realm = self.request_validator.validate_requested_realms(
177 request.client_key, request.realms, request)
178
179 # Callback is normally never required, except for requests for
180 # a Temporary Credential as described in `Section 2.1`_
181 # .._`Section 2.1`: https://tools.ietf.org/html/rfc5849#section-2.1
182 valid_redirect = self.request_validator.validate_redirect_uri(
183 request.client_key, request.redirect_uri, request)
184 if not request.redirect_uri:
185 raise NotImplementedError('Redirect URI must either be provided '
186 'or set to a default during validation.')
187
188 valid_signature = self._check_signature(request)
189
190 # log the results to the validator_log
191 # this lets us handle internal reporting and analysis
192 request.validator_log['client'] = valid_client
193 request.validator_log['realm'] = valid_realm
194 request.validator_log['callback'] = valid_redirect
195 request.validator_log['signature'] = valid_signature
196
197 # We delay checking validity until the very end, using dummy values for
198 # calculations and fetching secrets/keys to ensure the flow of every
199 # request remains almost identical regardless of whether valid values
200 # have been supplied. This ensures near constant time execution and
201 # prevents malicious users from guessing sensitive information
202 v = all((valid_client, valid_realm, valid_redirect, valid_signature))
203 if not v:
204 log.info("[Failure] request verification failed.")
205 log.info("Valid client: %s.", valid_client)
206 log.info("Valid realm: %s.", valid_realm)
207 log.info("Valid callback: %s.", valid_redirect)
208 log.info("Valid signature: %s.", valid_signature)
209 return v, request