Client._add_user_auth() - Code Metrics - Inspection of "metrics" - FreeOpcUa/python-opcua - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#185)

by Olivier

created 2016-05-15 06:32 UTC

Client._add_user_auth() B

↳ Parent: Project

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	8
CRAP Score	6.9683

Metric	Value
cc	5
dl	0
loc	17
rs	8.5454
ccs	8
cts	14
cp	0.5714
crap	6.9683

from __future__ import division  # support for python2
from threading import Thread, Condition
import logging
try:
    from urllib.parse import urlparse
except ImportError:  # support for python2
    from urlparse import urlparse

from opcua import ua
from opcua.client.ua_client import UaClient
from opcua.common.node import Node
from opcua.common.manage_nodes import delete_nodes
from opcua.common.subscription import Subscription
from opcua.common import utils
from opcua.crypto import security_policies
use_crypto = True
try:
    from opcua.crypto import uacrypto
except ImportError:
    print("cryptography is not installed, use of crypto disabled")
    use_crypto = False


class KeepAlive(Thread):

    """
    Used by Client to keep session opened.
    OPCUA defines timeout both for sessions and secure channel
    """

    def __init__(self, client, timeout):
        Thread.__init__(self)
        self.logger = logging.getLogger(__name__)
        if timeout == 0:  # means no timeout bu we do not trust such servers
            timeout = 360000
        self.timeout = timeout
        self.client = client
        self._dostop = False
        self._cond = Condition()

    def run(self):
        self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout)
        server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State))
        while not self._dostop:
            with self._cond:
                self._cond.wait(self.timeout / 1000)
            if self._dostop:
                break
            self.logger.debug("renewing channel")
            self.client.open_secure_channel(renew=True)
            val = server_state.get_value()
            self.logger.debug("server state is: %s ", val)
        self.logger.debug("keepalive thread has stopped")

    def stop(self):
        self.logger.debug("stoping keepalive thread")
        self._dostop = True
        with self._cond:
            self._cond.notify_all()


class Client(object):

    """
    High level client to connect to an OPC-UA server.

    This class makes it easy to connect and browse address space.
    It attemps to expose as much functionality as possible
    but if you want more flexibility it is possible and adviced to
    use UaClient object, available as self.uaclient
    which offers the raw OPC-UA services interface.
    """

    def __init__(self, url, timeout=4):
        """
        used url argument to connect to server.
        if you are unsure of url, write at least hostname and port
        and call get_endpoints
        timeout is the timeout to get an answer for requests to server
        public member of this call are available to be set by API users

        """
        self.logger = logging.getLogger(__name__)
        self.server_url = urlparse(url)
        self.name = "Pure Python Client"
        self.description = self.name
        self.application_uri = "urn:freeopcua:client"
        self.product_uri = "urn:freeopcua.github.no:client"
        self.security_policy = ua.SecurityPolicy()
        self.secure_channel_id = None
        self.default_timeout = 3600000
        self.secure_channel_timeout = self.default_timeout
        self.session_timeout = self.default_timeout
        self._policy_ids = []
        self.uaclient = UaClient(timeout)
        self.user_certificate = None
        self.user_private_key = None
        self._session_counter = 1
        self.keepalive = None

    def __enter__(self):
        self.connect()
        return self

    def __exit__(self):
        self.disconnect()

    @staticmethod
    def find_endpoint(endpoints, security_mode, policy_uri):
        """
        Find endpoint with required security mode and policy URI
        """
        for ep in endpoints:
            if (ep.EndpointUrl.startswith(ua.OPC_TCP_SCHEME) and
                    ep.SecurityMode == security_mode and
                    ep.SecurityPolicyUri == policy_uri):
                return ep
        raise ua.UaError("No matching endpoints: {}, {}".format(
                         security_mode, policy_uri))

    def set_security_string(self, string):
        """
        Set SecureConnection mode. String format:
        Policy,Mode,certificate,private_key[,server_private_key]
        where Policy is Basic128Rsa15 or Basic256,
            Mode is Sign or SignAndEncrypt
            certificate, private_key and server_private_key are
                paths to .pem or .der files
        Call this before connect()
        """
        if not string:
            return
        parts = string.split(',')
        if len(parts) < 4:
            raise ua.UaError('Wrong format: `{}`, expected at least 4 comma-separated values'.format(string))
        policy_class = getattr(security_policies, 'SecurityPolicy' + parts[0])
        mode = getattr(ua.MessageSecurityMode, parts[1])
        return self.set_security(policy_class, parts[2], parts[3],
                                 parts[4] if len(parts) >= 5 else None, mode)

    def set_security(self, policy, certificate_path, private_key_path,
                     server_certificate_path=None,
                     mode=ua.MessageSecurityMode.SignAndEncrypt):
        """
        Set SecureConnection mode.
        Call this before connect()
        """
        if server_certificate_path is None:
            # load certificate from server's list of endpoints
            endpoints = self.connect_and_get_server_endpoints()
            endpoint = Client.find_endpoint(endpoints, mode, policy.URI)
            server_cert = uacrypto.x509_from_der(endpoint.ServerCertificate)
        else:
            server_cert = uacrypto.load_certificate(server_certificate_path)
        cert = uacrypto.load_certificate(certificate_path)
        pk = uacrypto.load_private_key(private_key_path)
        self.security_policy = policy(server_cert, cert, pk, mode)
        self.uaclient.set_security(self.security_policy)

    def load_client_certificate(self, path):
        """
        load our certificate from file, either pem or der
        """
        self.user_certificate = uacrypto.load_certificate(path)

    def load_private_key(self, path):
        """
        Load user private key. This is used for authenticating using certificate
        """
        self.user_private_key = uacrypto.load_private_key(path)

    def connect_and_get_server_endpoints(self):
        """
        Connect, ask server for endpoints, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        endpoints = self.get_endpoints()
        self.close_secure_channel()
        self.disconnect_socket()
        return endpoints

    def connect_and_find_servers(self):
        """
        Connect, ask server for a list of known servers, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()  # spec says it should not be necessary to open channel
        servers = self.find_servers()
        self.close_secure_channel()
        self.disconnect_socket()
        return servers

    def connect_and_find_servers_on_network(self):
        """
        Connect, ask server for a list of known servers on network, and disconnect
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        servers = self.find_servers_on_network()
        self.close_secure_channel()
        self.disconnect_socket()
        return servers

    def connect(self):
        """
        High level method
        Connect, create and activate session
        """
        self.connect_socket()
        self.send_hello()
        self.open_secure_channel()
        self.create_session()
        self.activate_session(username=self.server_url.username, password=self.server_url.password, certificate=self.user_certificate)

    def disconnect(self):
        """
        High level method
        Close session, secure channel and socket
        """
        self.close_session()
        self.close_secure_channel()
        self.disconnect_socket()

    def connect_socket(self):
        """
        connect to socket defined in url
        """
        self.uaclient.connect_socket(self.server_url.hostname, self.server_url.port)

    def disconnect_socket(self):
        self.uaclient.disconnect_socket()

    def send_hello(self):
        """
        Send OPC-UA hello to server
        """
        ack = self.uaclient.send_hello(self.server_url.geturl())
        # FIXME check ack

    def open_secure_channel(self, renew=False):
        """
        Open secure channel, if renew is True, renew channel
        """
        params = ua.OpenSecureChannelParameters()
        params.ClientProtocolVersion = 0
        params.RequestType = ua.SecurityTokenRequestType.Issue
        if renew:
            params.RequestType = ua.SecurityTokenRequestType.Renew
        params.SecurityMode = self.security_policy.Mode
        params.RequestedLifetime = self.secure_channel_timeout
        nonce = utils.create_nonce(self.security_policy.symmetric_key_size)   # length should be equal to the length of key of symmetric encryption
        params.ClientNonce = nonce	# this nonce is used to create a symmetric key
        result = self.uaclient.open_secure_channel(params)
        self.security_policy.make_symmetric_key(nonce, result.ServerNonce)
        self.secure_channel_timeout = result.SecurityToken.RevisedLifetime

    def close_secure_channel(self):
        return self.uaclient.close_secure_channel()

    def get_endpoints(self):
        params = ua.GetEndpointsParameters()
        params.EndpointUrl = self.server_url.geturl()
        return self.uaclient.get_endpoints(params)

    def register_server(self, server, discovery_configuration=None):
        """
        register a server to discovery server
        if discovery_configuration is provided, the newer register_server2 service call is used
        """
        serv = ua.RegisteredServer()
        serv.ServerUri = server.application_uri
        serv.ProductUri = server.product_uri
        serv.DiscoveryUrls = [server.endpoint.geturl()]
        serv.ServerType = server.application_type
        serv.ServerNames = [ua.LocalizedText(server.name)]
        serv.IsOnline = True
        if discovery_configuration:
            params = ua.RegisterServer2Parameters()
            params.Server = serv
            params.DiscoveryConfiguration = discovery_configuration
            return self.uaclient.register_server2(params)
        else:
            return self.uaclient.register_server(serv)

    def find_servers(self, uris=None):
        """
        send a FindServer request to the server. The answer should be a list of
        servers the server knows about
        A list of uris can be provided, only server having matching uris will be returned
        """
        if uris is None:
            uris = []
        params = ua.FindServersParameters()
        params.EndpointUrl = self.server_url.geturl()
        params.ServerUris = uris
        return self.uaclient.find_servers(params)

    def find_servers_on_network(self):
        params = ua.FindServersOnNetworkParameters()
        return self.uaclient.find_servers_on_network(params)

    def create_session(self):
        """
        send a CreateSessionRequest to server with reasonable parameters.
        If you want o modify settings look at code of this methods
        and make your own
        """
        desc = ua.ApplicationDescription()
        desc.ApplicationUri = self.application_uri
        desc.ProductUri = self.product_uri
        desc.ApplicationName = ua.LocalizedText(self.name)
        desc.ApplicationType = ua.ApplicationType.Client

        params = ua.CreateSessionParameters()
        nonce = utils.create_nonce(32)  # at least 32 random bytes for server to prove possession of private key (specs part 4, 5.6.2.2)
        params.ClientNonce = nonce
        params.ClientCertificate = self.security_policy.client_certificate
        params.ClientDescription = desc
        params.EndpointUrl = self.server_url.geturl()
        params.SessionName = self.description + " Session" + str(self._session_counter)
        params.RequestedSessionTimeout = 3600000
        params.MaxResponseMessageSize = 0  # means no max size
        response = self.uaclient.create_session(params)
        if self.security_policy.client_certificate is None:
            data = nonce
        else:
            data = self.security_policy.client_certificate + nonce
        self.security_policy.asymmetric_cryptography.verify(data, response.ServerSignature.Signature)
        self._server_nonce = response.ServerNonce
        if not self.security_policy.server_certificate:
            self.security_policy.server_certificate = response.ServerCertificate
        elif self.security_policy.server_certificate != response.ServerCertificate:
            raise ua.UaError("Server certificate mismatch")
        # remember PolicyId's: we will use them in activate_session()
        ep = Client.find_endpoint(response.ServerEndpoints, self.security_policy.Mode, self.security_policy.URI)
        self._policy_ids = ep.UserIdentityTokens
        self.session_timeout = response.RevisedSessionTimeout
        self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7)  # 0.7 is from spec
        self.keepalive.start()
        return response

    def server_policy_id(self, token_type, default):
        """
        Find PolicyId of server's UserTokenPolicy by token_type.
        Return default if there's no matching UserTokenPolicy.
        """
        for policy in self._policy_ids:
            if policy.TokenType == token_type:
                return policy.PolicyId
        return default

    def server_policy_uri(self, token_type):
        """
        Find SecurityPolicyUri of server's UserTokenPolicy by token_type.
        If SecurityPolicyUri is empty, use default SecurityPolicyUri
        of the endpoint
        """
        for policy in self._policy_ids:
            if policy.TokenType == token_type:
                if policy.SecurityPolicyUri:
                    return policy.SecurityPolicyUri
                else:   # empty URI means "use this endpoint's policy URI"
                    return self.security_policy.URI
        return self.security_policy.URI

    def activate_session(self, username=None, password=None, certificate=None):
        """
        Activate session using either username and password or private_key
        """
        params = ua.ActivateSessionParameters()
        challenge = b""
        if self.security_policy.server_certificate is not None:
            challenge += self.security_policy.server_certificate
        if self._server_nonce is not None:
            challenge += self._server_nonce
        params.ClientSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
        params.ClientSignature.Signature = self.security_policy.asymmetric_cryptography.signature(challenge)
        params.LocaleIds.append("en")
        if not username and not certificate:
            self._add_anonymous_auth(params)
        elif certificate:
            self._add_cetificate_auth(params, certificate, challenge)
        else:
            self._add_user_auth(params, username, password)
        return self.uaclient.activate_session(params)

    def _add_anonymous_auth(self, params):
        params.UserIdentityToken = ua.AnonymousIdentityToken()
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")

    def _add_certificate_auth(self, params, certificate, challenge):
        params.UserIdentityToken = ua.X509IdentityToken()
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
        params.UserIdentityToken.CertificateData = uacrypto.der_from_x509(certificate)
        # specs part 4, 5.6.3.1: the data to sign is created by appending
        # the last serverNonce to the serverCertificate
        sig = uacrypto.sign_sha1(self.user_private_key, challenge)
        params.UserTokenSignature = ua.SignatureData()
        params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
        params.UserTokenSignature.Signature = sig

    def _add_user_auth(self, params, username, password):
        params.UserIdentityToken = ua.UserNameIdentityToken()
        params.UserIdentityToken.UserName = username
        policy_uri = self.server_policy_uri(ua.UserTokenType.UserName)
        if not policy_uri or policy_uri == security_policies.POLICY_NONE_URI:
            # see specs part 4, 7.36.3: if the token is NOT encrypted,
            # then the password only contains UTF-8 encoded password
            # and EncryptionAlgorithm is null
            if self.server_url.password:
                self.logger.warning("Sending plain-text password")
                params.UserIdentityToken.Password = password
            params.UserIdentityToken.EncryptionAlgorithm = ''
        elif self.server_url.password:
            data, uri = self._encrypt_password(password, policy_uri)
            params.UserIdentityToken.Password = data 
            params.UserIdentityToken.EncryptionAlgorithm = uri
        params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")

    def _encrypt_password(self, password, policy_uri):
        pubkey = uacrypto.x509_from_der(self.security_policy.server_certificate).public_key()
        # see specs part 4, 7.36.3: if the token is encrypted, password
        # shall be converted to UTF-8 and serialized with server nonce
        passwd = bytes(password, "utf8")
        if self._server_nonce is not None:
            passwd += self._server_nonce
        etoken = ua.pack_bytes(passwd)
        data, uri = security_policies.encrypt_asymmetric(pubkey, etoken, policy_uri)

    def close_session(self):
        """
        Close session
        """
        if self.keepalive:
            self.keepalive.stop()
        return self.uaclient.close_session(True)

    def get_root_node(self):
        return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder))

    def get_objects_node(self):
        return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder))

    def get_server_node(self):
        return self.get_node(ua.FourByteNodeId(ua.ObjectIds.Server))

    def get_node(self, nodeid):
        """
        Get node using NodeId object or a string representing a NodeId
        """
        return Node(self.uaclient, nodeid)

    def create_subscription(self, period, handler):
        """
        Create a subscription.
        returns a Subscription object which allow
        to subscribe to events or data on server
        handler argument is a class with data_change and/or event methods.
        These methods will be called when notfication from server are received.
        See example-client.py.
        Do not do expensive/slow or network operation from these methods
        since they are called directly from receiving thread. This is a design choice,
        start another thread if you need to do such a thing.
        """
        params = ua.CreateSubscriptionParameters()
        params.RequestedPublishingInterval = period
        params.RequestedLifetimeCount = 3000
        params.RequestedMaxKeepAliveCount = 10000
        params.MaxNotificationsPerPublish = 10000
        params.PublishingEnabled = True
        params.Priority = 0
        return Subscription(self.uaclient, params, handler)

    def get_namespace_array(self):
        ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
        return ns_node.get_value()

    def get_namespace_index(self, uri):
        uries = self.get_namespace_array()
        return uries.index(uri)

    def delete_nodes(self, nodes, recursive=False):
        return delete_nodes(self.uaclient, nodes, recursive)
            


1	1	from __future__ import division # support for python2
2	1	from threading import Thread, Condition
3	1	import logging
4	1	try:
5	1	from urllib.parse import urlparse
6		except ImportError: # support for python2
7		from urlparse import urlparse
8
9	1	from opcua import ua
10	1	from opcua.client.ua_client import UaClient
11	1	from opcua.common.node import Node
12	1	from opcua.common.manage_nodes import delete_nodes
13	1	from opcua.common.subscription import Subscription
14	1	from opcua.common import utils
15	1	from opcua.crypto import security_policies
16	1	use_crypto = True
17	1	try:
18	1	from opcua.crypto import uacrypto
19	1	except ImportError:
20	1	print("cryptography is not installed, use of crypto disabled")
21	1	use_crypto = False
22
23
24	1	class KeepAlive(Thread):
25
26		"""
27		Used by Client to keep session opened.
28		OPCUA defines timeout both for sessions and secure channel
29		"""
30
31	1	def __init__(self, client, timeout):
32	1	Thread.__init__(self)
33	1	self.logger = logging.getLogger(__name__)
34	1	if timeout == 0: # means no timeout bu we do not trust such servers
35		timeout = 360000
36	1	self.timeout = timeout
37	1	self.client = client
38	1	self._dostop = False
39	1	self._cond = Condition()
40
41	1	def run(self):
42	1	self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout)
43	1	server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State))
44	1	while not self._dostop:
45	1	with self._cond:
46	1	self._cond.wait(self.timeout / 1000)
47	1	if self._dostop:
48	1	break
49		self.logger.debug("renewing channel")
50		self.client.open_secure_channel(renew=True)
51		val = server_state.get_value()
52		self.logger.debug("server state is: %s ", val)
53	1	self.logger.debug("keepalive thread has stopped")
54
55	1	def stop(self):
56	1	self.logger.debug("stoping keepalive thread")
57	1	self._dostop = True
58	1	with self._cond:
59	1	self._cond.notify_all()
60
61
62	1	class Client(object):
63
64		"""
65		High level client to connect to an OPC-UA server.
66
67		This class makes it easy to connect and browse address space.
68		It attemps to expose as much functionality as possible
69		but if you want more flexibility it is possible and adviced to
70		use UaClient object, available as self.uaclient
71		which offers the raw OPC-UA services interface.
72		"""
73
74	1	def __init__(self, url, timeout=4):
75		"""
76		used url argument to connect to server.
77		if you are unsure of url, write at least hostname and port
78		and call get_endpoints
79		timeout is the timeout to get an answer for requests to server
80		public member of this call are available to be set by API users
81
82		"""
83	1	self.logger = logging.getLogger(__name__)
84	1	self.server_url = urlparse(url)
85	1	self.name = "Pure Python Client"
86	1	self.description = self.name
87	1	self.application_uri = "urn:freeopcua:client"
88	1	self.product_uri = "urn:freeopcua.github.no:client"
89	1	self.security_policy = ua.SecurityPolicy()
90	1	self.secure_channel_id = None
91	1	self.default_timeout = 3600000
92	1	self.secure_channel_timeout = self.default_timeout
93	1	self.session_timeout = self.default_timeout
94	1	self._policy_ids = []
95	1	self.uaclient = UaClient(timeout)
96	1	self.user_certificate = None
97	1	self.user_private_key = None
98	1	self._session_counter = 1
99	1	self.keepalive = None
100
101	1	def __enter__(self):
102		self.connect()
103		return self
104
105	1	def __exit__(self):
106		self.disconnect()
107
108	1	@staticmethod
109		def find_endpoint(endpoints, security_mode, policy_uri):
110		"""
111		Find endpoint with required security mode and policy URI
112		"""
113	1	for ep in endpoints:
114	1	if (ep.EndpointUrl.startswith(ua.OPC_TCP_SCHEME) and
115		ep.SecurityMode == security_mode and
116		ep.SecurityPolicyUri == policy_uri):
117	1	return ep
118		raise ua.UaError("No matching endpoints: {}, {}".format(
119		security_mode, policy_uri))
120
121	1	def set_security_string(self, string):
122		"""
123		Set SecureConnection mode. String format:
124		Policy,Mode,certificate,private_key[,server_private_key]
125		where Policy is Basic128Rsa15 or Basic256,
126		Mode is Sign or SignAndEncrypt
127		certificate, private_key and server_private_key are
128		paths to .pem or .der files
129		Call this before connect()
130		"""
131		if not string:
132		return
133		parts = string.split(',')
134		if len(parts) < 4:
135		raise ua.UaError('Wrong format: `{}`, expected at least 4 comma-separated values'.format(string))
136		policy_class = getattr(security_policies, 'SecurityPolicy' + parts[0])
137		mode = getattr(ua.MessageSecurityMode, parts[1])
138		return self.set_security(policy_class, parts[2], parts[3],
139		parts[4] if len(parts) >= 5 else None, mode)
140
141	1	def set_security(self, policy, certificate_path, private_key_path,
142		server_certificate_path=None,
143		mode=ua.MessageSecurityMode.SignAndEncrypt):
144		"""
145		Set SecureConnection mode.
146		Call this before connect()
147		"""
148		if server_certificate_path is None:
149		# load certificate from server's list of endpoints
150		endpoints = self.connect_and_get_server_endpoints()
151		endpoint = Client.find_endpoint(endpoints, mode, policy.URI)
152		server_cert = uacrypto.x509_from_der(endpoint.ServerCertificate)
153		else:
154		server_cert = uacrypto.load_certificate(server_certificate_path)
155		cert = uacrypto.load_certificate(certificate_path)
156		pk = uacrypto.load_private_key(private_key_path)
157		self.security_policy = policy(server_cert, cert, pk, mode)
158		self.uaclient.set_security(self.security_policy)
159
160	1	def load_client_certificate(self, path):
161		"""
162		load our certificate from file, either pem or der
163		"""
164		self.user_certificate = uacrypto.load_certificate(path)
165
166	1	def load_private_key(self, path):
167		"""
168		Load user private key. This is used for authenticating using certificate
169		"""
170		self.user_private_key = uacrypto.load_private_key(path)
171
172	1	def connect_and_get_server_endpoints(self):
173		"""
174		Connect, ask server for endpoints, and disconnect
175		"""
176		self.connect_socket()
177		self.send_hello()
178		self.open_secure_channel()
179		endpoints = self.get_endpoints()
180		self.close_secure_channel()
181		self.disconnect_socket()
182		return endpoints
183
184	1	def connect_and_find_servers(self):
185		"""
186		Connect, ask server for a list of known servers, and disconnect
187		"""
188		self.connect_socket()
189		self.send_hello()
190		self.open_secure_channel() # spec says it should not be necessary to open channel
191		servers = self.find_servers()
192		self.close_secure_channel()
193		self.disconnect_socket()
194		return servers
195
196	1	def connect_and_find_servers_on_network(self):
197		"""
198		Connect, ask server for a list of known servers on network, and disconnect
199		"""
200		self.connect_socket()
201		self.send_hello()
202		self.open_secure_channel()
203		servers = self.find_servers_on_network()
204		self.close_secure_channel()
205		self.disconnect_socket()
206		return servers
207
208	1	def connect(self):
209		"""
210		High level method
211		Connect, create and activate session
212		"""
213	1	self.connect_socket()
214	1	self.send_hello()
215	1	self.open_secure_channel()
216	1	self.create_session()
217	1	self.activate_session(username=self.server_url.username, password=self.server_url.password, certificate=self.user_certificate)
218
219	1	def disconnect(self):
220		"""
221		High level method
222		Close session, secure channel and socket
223		"""
224	1	self.close_session()
225	1	self.close_secure_channel()
226	1	self.disconnect_socket()
227
228	1	def connect_socket(self):
229		"""
230		connect to socket defined in url
231		"""
232	1	self.uaclient.connect_socket(self.server_url.hostname, self.server_url.port)
233
234	1	def disconnect_socket(self):
235	1	self.uaclient.disconnect_socket()
236
237	1	def send_hello(self):
238		"""
239		Send OPC-UA hello to server
240		"""
241	1	ack = self.uaclient.send_hello(self.server_url.geturl())
242		# FIXME check ack
243
244	1	def open_secure_channel(self, renew=False):
245		"""
246		Open secure channel, if renew is True, renew channel
247		"""
248	1	params = ua.OpenSecureChannelParameters()
249	1	params.ClientProtocolVersion = 0
250	1	params.RequestType = ua.SecurityTokenRequestType.Issue
251	1	if renew:
252		params.RequestType = ua.SecurityTokenRequestType.Renew
253	1	params.SecurityMode = self.security_policy.Mode
254	1	params.RequestedLifetime = self.secure_channel_timeout
255	1	nonce = utils.create_nonce(self.security_policy.symmetric_key_size) # length should be equal to the length of key of symmetric encryption
256	1	params.ClientNonce = nonce # this nonce is used to create a symmetric key
257	1	result = self.uaclient.open_secure_channel(params)
258	1	self.security_policy.make_symmetric_key(nonce, result.ServerNonce)
259	1	self.secure_channel_timeout = result.SecurityToken.RevisedLifetime
260
261	1	def close_secure_channel(self):
262	1	return self.uaclient.close_secure_channel()
263
264	1	def get_endpoints(self):
265	1	params = ua.GetEndpointsParameters()
266	1	params.EndpointUrl = self.server_url.geturl()
267	1	return self.uaclient.get_endpoints(params)
268
269	1	def register_server(self, server, discovery_configuration=None):
270		"""
271		register a server to discovery server
272		if discovery_configuration is provided, the newer register_server2 service call is used
273		"""
274	1	serv = ua.RegisteredServer()
275	1	serv.ServerUri = server.application_uri
276	1	serv.ProductUri = server.product_uri
277	1	serv.DiscoveryUrls = [server.endpoint.geturl()]
278	1	serv.ServerType = server.application_type
279	1	serv.ServerNames = [ua.LocalizedText(server.name)]
280	1	serv.IsOnline = True
281	1	if discovery_configuration:
282		params = ua.RegisterServer2Parameters()
283		params.Server = serv
284		params.DiscoveryConfiguration = discovery_configuration
285		return self.uaclient.register_server2(params)
286		else:
287	1	return self.uaclient.register_server(serv)
288
289	1	def find_servers(self, uris=None):
290		"""
291		send a FindServer request to the server. The answer should be a list of
292		servers the server knows about
293		A list of uris can be provided, only server having matching uris will be returned
294		"""
295	1	if uris is None:
296	1	uris = []
297	1	params = ua.FindServersParameters()
298	1	params.EndpointUrl = self.server_url.geturl()
299	1	params.ServerUris = uris
300	1	return self.uaclient.find_servers(params)
301
302	1	def find_servers_on_network(self):
303		params = ua.FindServersOnNetworkParameters()
304		return self.uaclient.find_servers_on_network(params)
305
306	1	def create_session(self):
307		"""
308		send a CreateSessionRequest to server with reasonable parameters.
309		If you want o modify settings look at code of this methods
310		and make your own
311		"""
312	1	desc = ua.ApplicationDescription()
313	1	desc.ApplicationUri = self.application_uri
314	1	desc.ProductUri = self.product_uri
315	1	desc.ApplicationName = ua.LocalizedText(self.name)
316	1	desc.ApplicationType = ua.ApplicationType.Client
317
318	1	params = ua.CreateSessionParameters()
319	1	nonce = utils.create_nonce(32) # at least 32 random bytes for server to prove possession of private key (specs part 4, 5.6.2.2)
320	1	params.ClientNonce = nonce
321	1	params.ClientCertificate = self.security_policy.client_certificate
322	1	params.ClientDescription = desc
323	1	params.EndpointUrl = self.server_url.geturl()
324	1	params.SessionName = self.description + " Session" + str(self._session_counter)
325	1	params.RequestedSessionTimeout = 3600000
326	1	params.MaxResponseMessageSize = 0 # means no max size
327	1	response = self.uaclient.create_session(params)
328	1	if self.security_policy.client_certificate is None:
329	1	data = nonce
330		else:
331		data = self.security_policy.client_certificate + nonce
332	1	self.security_policy.asymmetric_cryptography.verify(data, response.ServerSignature.Signature)
333	1	self._server_nonce = response.ServerNonce
334	1	if not self.security_policy.server_certificate:
335	1	self.security_policy.server_certificate = response.ServerCertificate
336		elif self.security_policy.server_certificate != response.ServerCertificate:
337		raise ua.UaError("Server certificate mismatch")
338		# remember PolicyId's: we will use them in activate_session()
339	1	ep = Client.find_endpoint(response.ServerEndpoints, self.security_policy.Mode, self.security_policy.URI)
340	1	self._policy_ids = ep.UserIdentityTokens
341	1	self.session_timeout = response.RevisedSessionTimeout
342	1	self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7) # 0.7 is from spec
343	1	self.keepalive.start()
344	1	return response
345
346	1	def server_policy_id(self, token_type, default):
347		"""
348		Find PolicyId of server's UserTokenPolicy by token_type.
349		Return default if there's no matching UserTokenPolicy.
350		"""
351	1	for policy in self._policy_ids:
352	1	if policy.TokenType == token_type:
353	1	return policy.PolicyId
354		return default
355
356	1	def server_policy_uri(self, token_type):
357		"""
358		Find SecurityPolicyUri of server's UserTokenPolicy by token_type.
359		If SecurityPolicyUri is empty, use default SecurityPolicyUri
360		of the endpoint
361		"""
362	1	for policy in self._policy_ids:
363	1	if policy.TokenType == token_type:
364	1	if policy.SecurityPolicyUri:
365		return policy.SecurityPolicyUri
366		else: # empty URI means "use this endpoint's policy URI"
367	1	return self.security_policy.URI
368		return self.security_policy.URI
369
370	1	def activate_session(self, username=None, password=None, certificate=None):
371		"""
372		Activate session using either username and password or private_key
373		"""
374	1	params = ua.ActivateSessionParameters()
375	1	challenge = b""
376	1	if self.security_policy.server_certificate is not None:
377		challenge += self.security_policy.server_certificate
378	1	if self._server_nonce is not None:
379	1	challenge += self._server_nonce
380	1	params.ClientSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
381	1	params.ClientSignature.Signature = self.security_policy.asymmetric_cryptography.signature(challenge)
382	1	params.LocaleIds.append("en")
383	1	if not username and not certificate:
384	1	self._add_anonymous_auth(params)
385	1	elif certificate:
386		self._add_cetificate_auth(params, certificate, challenge)
387		else:
388	1	self._add_user_auth(params, username, password)
389	1	return self.uaclient.activate_session(params)
390
391	1	def _add_anonymous_auth(self, params):
392	1	params.UserIdentityToken = ua.AnonymousIdentityToken()
393	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")
394
395	1	def _add_certificate_auth(self, params, certificate, challenge):
396		params.UserIdentityToken = ua.X509IdentityToken()
397		params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
398		params.UserIdentityToken.CertificateData = uacrypto.der_from_x509(certificate)
399		# specs part 4, 5.6.3.1: the data to sign is created by appending
400		# the last serverNonce to the serverCertificate
401		sig = uacrypto.sign_sha1(self.user_private_key, challenge)
402		params.UserTokenSignature = ua.SignatureData()
403		params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
404		params.UserTokenSignature.Signature = sig
405
406	1	def _add_user_auth(self, params, username, password):
407	1	params.UserIdentityToken = ua.UserNameIdentityToken()
408	1	params.UserIdentityToken.UserName = username
409	1	policy_uri = self.server_policy_uri(ua.UserTokenType.UserName)
410	1	if not policy_uri or policy_uri == security_policies.POLICY_NONE_URI:
411		# see specs part 4, 7.36.3: if the token is NOT encrypted,
412		# then the password only contains UTF-8 encoded password
413		# and EncryptionAlgorithm is null
414	1	if self.server_url.password:
415		self.logger.warning("Sending plain-text password")
416		params.UserIdentityToken.Password = password
417	1	params.UserIdentityToken.EncryptionAlgorithm = ''
418		elif self.server_url.password:
419		data, uri = self._encrypt_password(password, policy_uri)
420		params.UserIdentityToken.Password = data
421		params.UserIdentityToken.EncryptionAlgorithm = uri
422	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")
423
424	1	def _encrypt_password(self, password, policy_uri):
425		pubkey = uacrypto.x509_from_der(self.security_policy.server_certificate).public_key()
426		# see specs part 4, 7.36.3: if the token is encrypted, password
427		# shall be converted to UTF-8 and serialized with server nonce
428		passwd = bytes(password, "utf8")
429		if self._server_nonce is not None:
430		passwd += self._server_nonce
431		etoken = ua.pack_bytes(passwd)
432		data, uri = security_policies.encrypt_asymmetric(pubkey, etoken, policy_uri)
433
434	1	def close_session(self):
435		"""
436		Close session
437		"""
438	1	if self.keepalive:
439	1	self.keepalive.stop()
440	1	return self.uaclient.close_session(True)
441
442	1	def get_root_node(self):
443	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder))
444
445	1	def get_objects_node(self):
446	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder))
447
448	1	def get_server_node(self):
449	1	return self.get_node(ua.FourByteNodeId(ua.ObjectIds.Server))
450
451	1	def get_node(self, nodeid):
452		"""
453		Get node using NodeId object or a string representing a NodeId
454		"""
455	1	return Node(self.uaclient, nodeid)
456
457	1	def create_subscription(self, period, handler):
458		"""
459		Create a subscription.
460		returns a Subscription object which allow
461		to subscribe to events or data on server
462		handler argument is a class with data_change and/or event methods.
463		These methods will be called when notfication from server are received.
464		See example-client.py.
465		Do not do expensive/slow or network operation from these methods
466		since they are called directly from receiving thread. This is a design choice,
467		start another thread if you need to do such a thing.
468		"""
469	1	params = ua.CreateSubscriptionParameters()
470	1	params.RequestedPublishingInterval = period
471	1	params.RequestedLifetimeCount = 3000
472	1	params.RequestedMaxKeepAliveCount = 10000
473	1	params.MaxNotificationsPerPublish = 10000
474	1	params.PublishingEnabled = True
475	1	params.Priority = 0
476	1	return Subscription(self.uaclient, params, handler)
477
478	1	def get_namespace_array(self):
479	1	ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
480	1	return ns_node.get_value()
481
482	1	def get_namespace_index(self, uri):
483	1	uries = self.get_namespace_array()
484	1	return uries.index(uri)
485
486	1	def delete_nodes(self, nodes, recursive=False):
487	1	return delete_nodes(self.uaclient, nodes, recursive)
488
489

FreeOpcUa / python-opcua

Pull Request — master (#185)

Client._add_user_auth() B

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