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Diffstat (limited to 'src/leap/soledad_server/__init__.py')
| -rw-r--r-- | src/leap/soledad_server/__init__.py | 393 |
1 files changed, 393 insertions, 0 deletions
diff --git a/src/leap/soledad_server/__init__.py b/src/leap/soledad_server/__init__.py new file mode 100644 index 00000000..bea5d5fd --- /dev/null +++ b/src/leap/soledad_server/__init__.py @@ -0,0 +1,393 @@ +# -*- 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) |