diff options
| -rw-r--r-- | README.rst | 33 | ||||
| -rw-r--r-- | client/src/leap/soledad/client/sync.py | 12 | ||||
| -rw-r--r-- | common/changes/create_db_cmd | 2 | ||||
| -rw-r--r-- | common/src/leap/soledad/common/command.py | 55 | ||||
| -rw-r--r-- | common/src/leap/soledad/common/couch.py | 62 | ||||
| -rw-r--r-- | common/src/leap/soledad/common/tests/test_command.py | 53 | ||||
| -rw-r--r-- | common/src/leap/soledad/common/tests/test_couch.py | 45 | ||||
| -rw-r--r-- | common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py | 6 | ||||
| -rw-r--r-- | common/src/leap/soledad/common/tests/test_server.py | 12 | ||||
| -rw-r--r-- | server/changes/create_db_cmd | 3 | ||||
| -rwxr-xr-x | server/pkg/create-user-db | 59 | ||||
| -rw-r--r-- | server/src/leap/soledad/server/__init__.py | 3 |
12 files changed, 312 insertions, 33 deletions
@@ -55,3 +55,36 @@ to run tests in development mode you must do the following:: Note that to run CouchDB tests, be sure you have ``CouchDB`` installed on your system. + + +Privileges +----- +In order to prevent privilege escalation, Soledad should not be run as a +database administrator. This implies the following side effects: + +----------------- +Database creation: +----------------- +Can be done via a script located in ``server/pkg/create-user-db`` +It reads a netrc file that should be placed on +``/etc/couchdb/couchdb-admin.netrc``. +That file holds the admin credentials in netrc format and should be accessible +only by 'soledad-admin' user. + +The debian package will do the following in order to automate this: + +* create a user ``soledad-admin`` +* make this script available as ``create-user-db`` in ``/usr/bin`` +* grant restricted sudo access, that only enables user ``soledad`` to call this + exact command via ``soledad-admin`` user. + +The server side process, configured via ``/etc/leap/soledad-server.conf``, will +then use a parameter called 'create_cmd' to know which command is used to +allocate new databases. All steps of creation process is then handled +automatically by the server, following the same logic as u1db server. + +------------------ +Database deletion: +------------------ +No code at all handles this and privilege to do so needs to be removed as +explained before. This can be automated via a simple cron job. diff --git a/client/src/leap/soledad/client/sync.py b/client/src/leap/soledad/client/sync.py index 110baa0a..225d3e2d 100644 --- a/client/src/leap/soledad/client/sync.py +++ b/client/src/leap/soledad/client/sync.py @@ -69,9 +69,15 @@ class SoledadSynchronizer(Synchronizer): # get target identifier, its current generation, # and its last-seen database generation for this source ensure_callback = None - (self.target_replica_uid, target_gen, target_trans_id, - target_my_gen, target_my_trans_id) = yield \ - sync_target.get_sync_info(self.source._replica_uid) + try: + (self.target_replica_uid, target_gen, target_trans_id, + target_my_gen, target_my_trans_id) = yield \ + sync_target.get_sync_info(self.source._replica_uid) + except errors.DatabaseDoesNotExist: + logger.debug("Database isn't ready on server. Will be created.") + self.target_replica_uid = None + target_gen, target_trans_id = 0, '' + target_my_gen, target_my_trans_id = 0, '' logger.debug( "Soledad target sync info:\n" diff --git a/common/changes/create_db_cmd b/common/changes/create_db_cmd new file mode 100644 index 00000000..00bbdf71 --- /dev/null +++ b/common/changes/create_db_cmd @@ -0,0 +1,2 @@ + o Add a sanitized command executor for database creation and re-enable + user database creation on CouchServerState via command line. diff --git a/common/src/leap/soledad/common/command.py b/common/src/leap/soledad/common/command.py new file mode 100644 index 00000000..811bf135 --- /dev/null +++ b/common/src/leap/soledad/common/command.py @@ -0,0 +1,55 @@ +# -*- coding: utf-8 -*- +# command.py +# Copyright (C) 2015 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/>. + + +""" +Utility to sanitize and run shell commands. +""" + + +import subprocess + + +def exec_validated_cmd(cmd, argument, validator=None): + """ + Executes cmd, validating argument with a validator function. + + :param cmd: command. + :type dbname: str + :param argument: argument. + :type argument: str + :param validator: optional function to validate argument + :type validator: function + + :return: exit code and stdout or stderr (if code != 0) + :rtype: (int, str) + """ + if validator and not validator(argument): + return 1, "invalid argument" + command = cmd.split(' ') + command.append(argument) + try: + process = subprocess.Popen(command, stdout=subprocess.PIPE, + stderr=subprocess.PIPE) + except OSError, e: + return 1, e + (out, err) = process.communicate() + code = process.wait() + if code is not 0: + return code, err + else: + return code, out diff --git a/common/src/leap/soledad/common/couch.py b/common/src/leap/soledad/common/couch.py index 38041c09..4c5f6400 100644 --- a/common/src/leap/soledad/common/couch.py +++ b/common/src/leap/soledad/common/couch.py @@ -60,6 +60,7 @@ from u1db.remote.server_state import ServerState from leap.soledad.common import ddocs, errors +from leap.soledad.common.command import exec_validated_cmd from leap.soledad.common.document import SoledadDocument @@ -434,6 +435,7 @@ class CouchDatabase(CommonBackend): self._set_replica_uid(replica_uid) if ensure_ddocs: self.ensure_ddocs_on_db() + self.ensure_security_ddoc() self._cache = None @property @@ -466,6 +468,21 @@ class CouchDatabase(CommonBackend): getattr(ddocs, ddoc_name))) self._database.save(ddoc) + def ensure_security_ddoc(self): + """ + Make sure that only soledad user is able to access this database as + an unprivileged member, meaning that administration access will + be forbidden even inside an user database. + The goal is to make sure that only the lowest access level is given + to the unprivileged CouchDB user set on the server process. + This is achieved by creating a _security design document, see: + http://docs.couchdb.org/en/latest/api/database/security.html + """ + security = self._database.security + security['members'] = {'names': ['soledad'], 'roles': []} + security['admins'] = {'names': [], 'roles': []} + self._database.security = security + def get_sync_target(self): """ Return a SyncTarget object, for another u1db to synchronize with. @@ -1374,13 +1391,27 @@ class CouchSyncTarget(CommonSyncTarget): source_replica_transaction_id) +def is_db_name_valid(name): + """ + Validate a user database using a regular expression. + + :param name: database name. + :type name: str + + :return: boolean for name vailidity + :rtype: bool + """ + db_name_regex = "^user-[a-f0-9]+$" + return re.match(db_name_regex, name) is not None + + class CouchServerState(ServerState): """ Inteface of the WSGI server with the CouchDB backend. """ - def __init__(self, couch_url): + def __init__(self, couch_url, create_cmd=None): """ Initialize the couch server state. @@ -1388,6 +1419,7 @@ class CouchServerState(ServerState): :type couch_url: str """ self.couch_url = couch_url + self.create_cmd = create_cmd def open_database(self, dbname): """ @@ -1409,20 +1441,28 @@ class CouchServerState(ServerState): """ Ensure couch database exists. - Usually, this method is used by the server to ensure the existence of - a database. In our setup, the Soledad user that accesses the underlying - couch server should never have permission to create (or delete) - databases. But, in case it ever does, by raising an exception here we - have one more guarantee that no modified client will be able to - enforce creation of a database when syncing. - :param dbname: The name of the database to ensure. :type dbname: str - :raise Unauthorized: Always, because Soledad server is not allowed to - create databases. + :raise Unauthorized: If disabled or other error was raised. + + :return: The CouchDatabase object and its replica_uid. + :rtype: (CouchDatabase, str) """ - raise Unauthorized() + if not self.create_cmd: + raise Unauthorized() + else: + code, out = exec_validated_cmd(self.create_cmd, dbname, + validator=is_db_name_valid) + if code is not 0: + logger.error(""" + Error while creating database (%s) with (%s) command. + Output: %s + Exit code: %d + """ % (dbname, self.create_cmd, out, code)) + raise Unauthorized() + db = self.open_database(dbname) + return db, db.replica_uid def delete_database(self, dbname): """ diff --git a/common/src/leap/soledad/common/tests/test_command.py b/common/src/leap/soledad/common/tests/test_command.py new file mode 100644 index 00000000..c386bdd2 --- /dev/null +++ b/common/src/leap/soledad/common/tests/test_command.py @@ -0,0 +1,53 @@ +# -*- coding: utf-8 -*- +# test_command.py +# Copyright (C) 2015 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/>. +""" +Tests for command execution using a validator function for arguments. +""" +from twisted.trial import unittest +from leap.soledad.common.command import exec_validated_cmd + + +class ExecuteValidatedCommandTest(unittest.TestCase): + + def test_argument_validation(self): + validator = lambda arg: True if arg is 'valid' else False + status, out = exec_validated_cmd("command", "invalid arg", validator) + self.assertEquals(status, 1) + self.assertEquals(out, "invalid argument") + status, out = exec_validated_cmd("echo", "valid", validator) + self.assertEquals(status, 0) + self.assertEquals(out, "valid\n") + + def test_return_status_code_success(self): + status, out = exec_validated_cmd("echo", "arg") + self.assertEquals(status, 0) + self.assertEquals(out, "arg\n") + + def test_handle_command_with_spaces(self): + status, out = exec_validated_cmd("echo I am", "an argument") + self.assertEquals(status, 0, out) + self.assertEquals(out, "I am an argument\n") + + def test_handle_oserror_on_invalid_command(self): + status, out = exec_validated_cmd("inexistent command with", "args") + self.assertEquals(status, 1) + self.assertIn("No such file or directory", out) + + def test_return_status_code_number_on_failure(self): + status, out = exec_validated_cmd("ls", "user-bebacafe") + self.assertNotEquals(status, 0) + self.assertIn('No such file or directory\n', out) diff --git a/common/src/leap/soledad/common/tests/test_couch.py b/common/src/leap/soledad/common/tests/test_couch.py index c8d13667..d1a07a3a 100644 --- a/common/src/leap/soledad/common/tests/test_couch.py +++ b/common/src/leap/soledad/common/tests/test_couch.py @@ -28,6 +28,8 @@ from couchdb.client import Server from uuid import uuid4 from testscenarios import TestWithScenarios +from twisted.trial import unittest +from mock import Mock from u1db import errors as u1db_errors from u1db import SyncTarget @@ -1498,3 +1500,46 @@ class CouchDatabaseExceptionsTests(CouchDBTestCase): self.db._get_transaction_log) self.create_db(ensure=True, dbname=self.db._dbname) self.db._get_transaction_log() + + def test_ensure_security_doc(self): + """ + Ensure_security creates a _security ddoc to ensure that only soledad + will have the lowest privileged access to an user db. + """ + self.create_db(ensure=False) + self.assertFalse(self.db._database.security) + self.db.ensure_security_ddoc() + security_ddoc = self.db._database.security + self.assertIn('admins', security_ddoc) + self.assertFalse(security_ddoc['admins']['names']) + self.assertIn('members', security_ddoc) + self.assertIn('soledad', security_ddoc['members']['names']) + + +class DatabaseNameValidationTest(unittest.TestCase): + + def test_database_name_validation(self): + self.assertFalse(couch.is_db_name_valid("user-deadbeef | cat /secret")) + self.assertTrue(couch.is_db_name_valid("user-cafe1337")) + + +class CommandBasedDBCreationTest(unittest.TestCase): + + def test_ensure_db_using_custom_command(self): + state = couch.CouchServerState("url", create_cmd="echo") + mock_db = Mock() + mock_db.replica_uid = 'replica_uid' + state.open_database = Mock(return_value=mock_db) + db, replica_uid = state.ensure_database("user-1337") # works + self.assertEquals(mock_db, db) + self.assertEquals(mock_db.replica_uid, replica_uid) + + def test_raises_unauthorized_on_failure(self): + state = couch.CouchServerState("url", create_cmd="inexistent") + self.assertRaises(u1db_errors.Unauthorized, + state.ensure_database, "user-1337") + + def test_raises_unauthorized_by_default(self): + state = couch.CouchServerState("url") + self.assertRaises(u1db_errors.Unauthorized, + state.ensure_database, "user-1337") diff --git a/common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py b/common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py index 3e8e8cce..507f2984 100644 --- a/common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py +++ b/common/src/leap/soledad/common/tests/test_couch_operations_atomicity.py @@ -35,17 +35,11 @@ from leap.soledad.common.tests.util import ( ) from leap.soledad.common.tests.test_couch import CouchDBTestCase from leap.soledad.common.tests.u1db_tests import TestCaseWithServer -from leap.soledad.common.tests.test_server import _couch_ensure_database REPEAT_TIMES = 20 -# monkey path CouchServerState so it can ensure databases. - -CouchServerState.ensure_database = _couch_ensure_database - - class CouchAtomicityTestCase(CouchDBTestCase, TestCaseWithServer): @staticmethod diff --git a/common/src/leap/soledad/common/tests/test_server.py b/common/src/leap/soledad/common/tests/test_server.py index f512d6c1..19d2907d 100644 --- a/common/src/leap/soledad/common/tests/test_server.py +++ b/common/src/leap/soledad/common/tests/test_server.py @@ -46,18 +46,6 @@ from leap.soledad.server import LockResource from leap.soledad.server.auth import URLToAuthorization -# monkey path CouchServerState so it can ensure databases. - -def _couch_ensure_database(self, dbname): - db = CouchDatabase.open_database( - self.couch_url + '/' + dbname, - create=True, - ensure_ddocs=True) - return db, db._replica_uid - -CouchServerState.ensure_database = _couch_ensure_database - - class ServerAuthorizationTestCase(BaseSoledadTest): """ diff --git a/server/changes/create_db_cmd b/server/changes/create_db_cmd new file mode 100644 index 00000000..cee0a935 --- /dev/null +++ b/server/changes/create_db_cmd @@ -0,0 +1,3 @@ + o Adds a new config parameter 'create_cmd', which allows sysadmin to specify + which command will create a database. That command was added in + pkg/create-user-db and debian package automates steps needed for sudo access. diff --git a/server/pkg/create-user-db b/server/pkg/create-user-db new file mode 100755 index 00000000..1a7e77a7 --- /dev/null +++ b/server/pkg/create-user-db @@ -0,0 +1,59 @@ +#!/usr/bin/env python +# -*- coding: utf-8 -*- +# create-user-db +# Copyright (C) 2015 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/>. +import os +import sys +import netrc +import argparse +from leap.soledad.common.couch import CouchDatabase +from leap.soledad.common.couch import is_db_name_valid + + +description = """ +Creates a user database. +This is meant to be used by Soledad Server. +""" +parser = argparse.ArgumentParser(description=description) +parser.add_argument('dbname', metavar='user-d34db33f', type=str, + help='database name on the format user-{uuid4}') +NETRC_PATH = '/etc/couchdb/couchdb-admin.netrc' + + +def url_for_db(dbname): + if not os.path.exists(NETRC_PATH): + print ('netrc not found in %s' % NETRC_PATH) + sys.exit(1) + parsed_netrc = netrc.netrc(NETRC_PATH) + host, (login, _, password) = parsed_netrc.hosts.items()[0] + url = ('http://%(login)s:%(password)s@%(host)s:5984/%(dbname)s' % { + 'login': login, + 'password': password, + 'host': host, + 'dbname': dbname}) + return url + + +if __name__ == '__main__': + args = parser.parse_args() + if not is_db_name_valid(args.dbname): + print ("Invalid name! %s" % args.dbname) + sys.exit(1) + url = url_for_db(args.dbname) + db = CouchDatabase.open_database(url=url, create=True, + replica_uid=None, ensure_ddocs=True) + print ('success! Created %s, replica_uid: %s' % + (db._dbname, db.replica_uid)) diff --git a/server/src/leap/soledad/server/__init__.py b/server/src/leap/soledad/server/__init__.py index 1b795016..bb1c6db0 100644 --- a/server/src/leap/soledad/server/__init__.py +++ b/server/src/leap/soledad/server/__init__.py @@ -285,6 +285,7 @@ def load_configuration(file_path): """ conf = { 'couch_url': 'http://localhost:5984', + 'create_cmd': None } config = configparser.ConfigParser() config.read(file_path) @@ -303,7 +304,7 @@ def load_configuration(file_path): def application(environ, start_response): conf = load_configuration('/etc/leap/soledad-server.conf') - state = CouchServerState(conf['couch_url']) + state = CouchServerState(conf['couch_url'], create_cmd=conf['create_cmd']) # WSGI application that may be used by `twistd -web` application = GzipMiddleware( SoledadTokenAuthMiddleware(SoledadApp(state))) |