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+# -*- coding: utf-8 -*-
+# server.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/>.
+
+
+"""
+A U1DB server that stores data using CouchDB as its persistence layer.
+
+This should be run with:
+ twistd -n web --wsgi=leap.soledad_server.application --port=2424
+"""
+
+import configparser
+import httplib
+import simplejson as json
+
+
+from hashlib import sha256
+from routes.mapper import Mapper
+from u1db import DBNAME_CONSTRAINTS
+from u1db.remote import http_app
+
+
+# Keep OpenSSL's tsafe before importing Twisted submodules so we can put
+# it back if Twisted==12.0.0 messes with it.
+from OpenSSL import tsafe
+old_tsafe = tsafe
+
+from twisted.web.wsgi import WSGIResource
+from twisted.internet import reactor
+from twisted.python import log
+
+from twisted import version
+if version.base() == "12.0.0":
+ # Put OpenSSL's tsafe back into place. This can probably be removed if we
+ # come to use Twisted>=12.3.0.
+ import sys
+ sys.modules['OpenSSL.tsafe'] = old_tsafe
+
+from couchdb.client import Server
+
+from leap.soledad import SECRETS_DOC_ID_HASH_PREFIX
+from leap.soledad_server.couch import CouchServerState
+
+
+#-----------------------------------------------------------------------------
+# Authentication
+#-----------------------------------------------------------------------------
+
+class Unauthorized(Exception):
+ """
+ User authentication failed.
+ """
+
+
+class URLToAuth(object):
+ """
+ Verify if actions can be performed by a user.
+ """
+
+ HTTP_METHOD_GET = 'GET'
+ HTTP_METHOD_PUT = 'PUT'
+ HTTP_METHOD_DELETE = 'DELETE'
+ HTTP_METHOD_POST = 'POST'
+
+ def __init__(self, uuid):
+ """
+ Initialize the mapper.
+
+ The C{uuid} is used to create the rules that will either allow or
+ disallow the user to perform specific actions.
+
+ @param uuid: The user uuid.
+ @type uuid: str
+ """
+ self._map = Mapper(controller_scan=None)
+ self._register_auth_info(self._uuid_dbname(uuid))
+
+ def is_authorized(self, environ):
+ """
+ Return whether an HTTP request that produced the CGI C{environ}
+ corresponds to an authorized action.
+
+ @param environ: Dictionary containing CGI variables.
+ @type environ: dict
+
+ @return: Whether the action is authorized or not.
+ @rtype: bool
+ """
+ return self._map.match(environ=environ) is not None
+
+ def _register(self, pattern, http_methods):
+ """
+ Register a C{pattern} in the mapper as valid for C{http_methods}.
+
+ @param pattern: The URL pattern that corresponds to the user action.
+ @type pattern: str
+ @param http_methods: A list of authorized HTTP methods.
+ @type http_methods: list of str
+ """
+ self._map.connect(
+ None, pattern, http_methods=http_methods,
+ conditions=dict(method=http_methods),
+ requirements={'dbname': DBNAME_CONSTRAINTS})
+
+ def _uuid_dbname(self, uuid):
+ """
+ Return the database name corresponding to C{uuid}.
+
+ @param uuid: The user uid.
+ @type uuid: str
+
+ @return: The database name corresponding to C{uuid}.
+ @rtype: str
+ """
+ return '%s%s' % (SoledadApp.USER_DB_PREFIX, uuid)
+
+ def _register_auth_info(self, dbname):
+ """
+ Register the authorization info in the mapper using C{dbname} as the
+ user's database name.
+
+ This method sets up the following authorization rules:
+
+ URL path | Authorized actions
+ --------------------------------------------------
+ / | GET
+ /shared-db | GET
+ /shared-db/docs | -
+ /shared-db/doc/{id} | GET, PUT, DELETE
+ /shared-db/sync-from/{source} | -
+ /user-db | GET, PUT, DELETE
+ /user-db/docs | -
+ /user-db/doc/{id} | -
+ /user-db/sync-from/{source} | GET, PUT, POST
+
+ @param dbname: The name of the user's database.
+ @type dbname: str
+ """
+ # auth info for global resource
+ self._register('/', [self.HTTP_METHOD_GET])
+ # auth info for shared-db database resource
+ self._register(
+ '/%s' % SoledadApp.SHARED_DB_NAME,
+ [self.HTTP_METHOD_GET])
+ # auth info for shared-db doc resource
+ self._register(
+ '/%s/doc/{id:.*}' % SoledadApp.SHARED_DB_NAME,
+ [self.HTTP_METHOD_GET, self.HTTP_METHOD_PUT,
+ self.HTTP_METHOD_DELETE])
+ # auth info for user-db database resource
+ self._register(
+ '/%s' % dbname,
+ [self.HTTP_METHOD_GET, self.HTTP_METHOD_PUT,
+ self.HTTP_METHOD_DELETE])
+ # auth info for user-db sync resource
+ self._register(
+ '/%s/sync-from/{source_replica_uid}' % dbname,
+ [self.HTTP_METHOD_GET, self.HTTP_METHOD_PUT,
+ self.HTTP_METHOD_POST])
+ # generate the regular expressions
+ self._map.create_regs()
+
+
+class SoledadAuthMiddleware(object):
+ """
+ Soledad Authentication WSGI middleware.
+
+ In general, databases are accessed using a token provided by the LEAP API.
+ Some special databases can be read without authentication.
+ """
+
+ TOKENS_DB = "tokens"
+ TOKENS_TYPE_KEY = "type"
+ TOKENS_TYPE_DEF = "Token"
+ TOKENS_USER_ID_KEY = "user_id"
+
+ HTTP_AUTH_KEY = "HTTP_AUTHORIZATION"
+ PATH_INFO_KEY = "PATH_INFO"
+
+ CONTENT_TYPE_JSON = ('content-type', 'application/json')
+
+ def __init__(self, app):
+ """
+ Initialize the Soledad Authentication Middleware.
+
+ @param app: The application to run on successfull authentication.
+ @type app: u1db.remote.http_app.HTTPApp
+ @param prefix: Auth app path prefix.
+ @type prefix: str
+ """
+ self._app = app
+
+ def _error(self, start_response, status, description, message=None):
+ """
+ Send a JSON serialized error to WSGI client.
+
+ @param start_response: Callable of the form start_response(status,
+ response_headers, exc_info=None).
+ @type start_response: callable
+ @param status: Status string of the form "999 Message here"
+ @type status: str
+ @param response_headers: A list of (header_name, header_value) tuples
+ describing the HTTP response header.
+ @type response_headers: list
+ @param description: The error description.
+ @type description: str
+ @param message: The error message.
+ @type message: str
+
+ @return: List with JSON serialized error message.
+ @rtype list
+ """
+ start_response("%d %s" % (status, httplib.responses[status]),
+ [self.CONTENT_TYPE_JSON])
+ err = {"error": description}
+ if message:
+ err['message'] = message
+ return [json.dumps(err)]
+
+ def __call__(self, environ, start_response):
+ """
+ Handle a WSGI call to the authentication application.
+
+ @param environ: Dictionary containing CGI variables.
+ @type environ: dict
+ @param start_response: Callable of the form start_response(status,
+ response_headers, exc_info=None).
+ @type start_response: callable
+
+ @return: Target application results if authentication succeeds, an
+ error message otherwise.
+ @rtype: list
+ """
+ unauth_err = lambda msg: self._error(start_response,
+ 401,
+ "unauthorized",
+ msg)
+
+ auth = environ.get(self.HTTP_AUTH_KEY)
+ if not auth:
+ return unauth_err("Missing Token Authentication.")
+
+ scheme, encoded = auth.split(None, 1)
+ if scheme.lower() != 'token':
+ return unauth_err("Missing Token Authentication")
+
+ uuid, token = encoded.decode('base64').split(':', 1)
+ if not self.verify_token(environ, uuid, token):
+ return unauth_err("Incorrect address or token.")
+
+ if not self.verify_action(uuid, environ):
+ return unauth_err("Unauthorized action.")
+
+ del environ[self.HTTP_AUTH_KEY]
+
+ return self._app(environ, start_response)
+
+ def verify_token(self, environ, uuid, token):
+ """
+ Verify if token is valid for authenticating this request.
+
+ @param environ: Dictionary containing CGI variables.
+ @type environ: dict
+ @param uuid: The user's uuid.
+ @type uuid: str
+ @param token: The authentication token.
+ @type token: str
+
+ @return: Whether the token is valid for authenticating the request.
+ @rtype: bool
+ """
+
+ server = Server(url=self._app.state.couch_url)
+ try:
+ dbname = self.TOKENS_DB
+ db = server[dbname]
+ token = db.get(token)
+ if token is None:
+ return False
+ return token[self.TOKENS_TYPE_KEY] == self.TOKENS_TYPE_DEF and \
+ token[self.TOKENS_USER_ID_KEY] == uuid
+ except Exception as e:
+ log.err(e)
+ return False
+ return True
+
+ def verify_action(self, uuid, environ):
+ """
+ Verify if the user is authorized to perform the requested action over
+ the requested database.
+
+ @param uuid: The user's uuid.
+ @type uuid: str
+ @param environ: Dictionary containing CGI variables.
+ @type environ: dict
+
+ @return: Whether the user is authorize to perform the requested action
+ over the requested db.
+ @rtype: bool
+ """
+ return URLToAuth(uuid).is_authorized(environ)
+
+
+#-----------------------------------------------------------------------------
+# Soledad WSGI application
+#-----------------------------------------------------------------------------
+
+class SoledadApp(http_app.HTTPApp):
+ """
+ Soledad WSGI application
+ """
+
+ SHARED_DB_NAME = 'shared'
+ """
+ The name of the shared database that holds user's encrypted secrets.
+ """
+
+ USER_DB_PREFIX = 'uuid-'
+ """
+ The string prefix of users' databases.
+ """
+
+ def __call__(self, environ, start_response):
+ """
+ Handle a WSGI call to the Soledad application.
+
+ @param environ: Dictionary containing CGI variables.
+ @type environ: dict
+ @param start_response: Callable of the form start_response(status,
+ response_headers, exc_info=None).
+ @type start_response: callable
+
+ @return: HTTP application results.
+ @rtype: list
+ """
+ # ensure the shared database exists
+ self.state.ensure_database(self.SHARED_DB_NAME)
+ return http_app.HTTPApp.__call__(self, environ, start_response)
+
+
+#-----------------------------------------------------------------------------
+# Auxiliary functions
+#-----------------------------------------------------------------------------
+
+def load_configuration(file_path):
+ """
+ Load server configuration from file.
+
+ @param file_path: The path to the configuration file.
+ @type file_path: str
+
+ @return: A dictionary with the configuration.
+ @rtype: dict
+ """
+ conf = {
+ 'couch_url': 'http://localhost:5984',
+ }
+ config = configparser.ConfigParser()
+ config.read(file_path)
+ if 'soledad-server' in config:
+ for key in conf:
+ if key in config['soledad-server']:
+ conf[key] = config['soledad-server'][key]
+ # TODO: implement basic parsing/sanitization of options comming from
+ # config file.
+ return conf
+
+
+#-----------------------------------------------------------------------------
+# Run as Twisted WSGI Resource
+#-----------------------------------------------------------------------------
+
+conf = load_configuration('/etc/leap/soledad-server.conf')
+state = CouchServerState(conf['couch_url'])
+
+# WSGI application that may be used by `twistd -web`
+application = SoledadAuthMiddleware(SoledadApp(state))
+
+resource = WSGIResource(reactor, reactor.getThreadPool(), application)