Client.set_user() - Code Metrics - Inspection of "username and password extracted from server_url to..." - FreeOpcUa/python-opcua - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 6c2020...aef276 )

by Olivier

created 2017-02-07 09:43 UTC

Client.set_user() A

↳ Parent: Project

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	1
CRAP Score	1.125

Importance

Changes	1
Bugs	0	Features	1

Metric	Value
cc	1
c	1
b	0
f	1
dl	0
loc	6
ccs	1
cts	2
cp	0.5
crap	1.125
rs	9.4285

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.xmlimporter import XmlImporter
from opcua.common.xmlexporter import XmlExporter
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
from opcua.common.shortcuts import Shortcuts
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 the session open.
    OPCUA defines timeout both for sessions and secure channel
    """

    def __init__(self, client, timeout):
        """
        :param session_timeout: Timeout to re-new the session
            in milliseconds.
        """
        Thread.__init__(self)
        self.logger = logging.getLogger(__name__)

        self.client = client
        self._dostop = False
        self._cond = Condition()
        self.timeout = timeout

        # some server support no timeout, but we do not trust them
        if self.timeout == 0:
            self.timeout = 3600000 # 1 hour

    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):
        """

        :param url: url of the server.
            if you are unsure of url, write at least hostname
            and port and call get_endpoints

        :param timeout:
            Each request sent to the server expects an answer within this
            time. The timeout is specified in seconds.
        """
        self.logger = logging.getLogger(__name__)
        self.server_url = urlparse(url)
        #take initial username and password from the url
        self._username = self.server_url.username
        self._password = self.server_url.password
        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.secure_channel_timeout = 3600000 # 1 hour
        self.session_timeout = 3600000 # 1 hour
        self._policy_ids = []
        self.uaclient = UaClient(timeout)
        self.user_certificate = None
        self.user_private_key = None
        self._session_counter = 1
        self.keepalive = None
        self.nodes = Shortcuts(self.uaclient)

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

    def __exit__(self, exc_type, exc_value, traceback):
        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: {0}, {1}".format(
                         security_mode, policy_uri))

    def set_user(self, username):
        """
        Set user name for the connection.
        initial user from the URL will be overwritten
        """
        self._username = username

    def set_password(self, pwd):
        """
        Set user password for the connection.
        initial password from the URL will be overwritten
        """
        self._password = pwd

    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: `{0}`, 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._username, password=self._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_certificate_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._password:
                self.logger.warning("Sending plain-text password")
                params.UserIdentityToken.Password = password
            params.UserIdentityToken.EncryptionAlgorithm = ''
        elif self._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 = password.encode("utf8")
        if self._server_nonce is not None:
            passwd += self._server_nonce
        etoken = ua.ua_binary.Primitives.Bytes.pack(passwd)
        data, uri = security_policies.encrypt_asymmetric(pubkey, etoken, policy_uri)
        return data, 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.
        period argument is either a publishing interval in seconds or a
        CreateSubscriptionParameters instance. The second option should be used,
        if the opcua-server has problems with the default options.
        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.
        """

        if isinstance(period, ua.CreateSubscriptionParameters):
             return Subscription(self.uaclient, period, handler)
        params = ua.CreateSubscriptionParameters()
        params.RequestedPublishingInterval = period
        params.RequestedLifetimeCount = 10000
        params.RequestedMaxKeepAliveCount = 3000
        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)

    def import_xml(self, path):
        """
        Import nodes defined in xml
        """
        importer = XmlImporter(self)
        return importer.import_xml(path)

    def export_xml(self, nodes, path):
        """
        Export defined nodes to xml
        """
        exp = XmlExporter(self)
        exp.build_etree(nodes)
        return exp.write_xml(path)

    def register_namespace(self, uri):
        """
        Register a new namespace. Nodes should in custom namespace, not 0.
        This method is mainly implemented for symetry with server
        """
        ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
        uries = ns_node.get_value()
        if uri in uries:
            return uries.index(uri)
        uries.append(uri)
        ns_node.set_value(uries)
        return len(uries) - 1




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.xmlimporter import XmlImporter
12	1	from opcua.common.xmlexporter import XmlExporter
13	1	from opcua.common.node import Node
14	1	from opcua.common.manage_nodes import delete_nodes
15	1	from opcua.common.subscription import Subscription
16	1	from opcua.common import utils
17	1	from opcua.crypto import security_policies
18	1	from opcua.common.shortcuts import Shortcuts
19	1	use_crypto = True
20	1	try:
21	1	from opcua.crypto import uacrypto
22		except ImportError:
23		print("cryptography is not installed, use of crypto disabled")
24		use_crypto = False
25
26
27	1	class KeepAlive(Thread):
28
29		"""
30		Used by Client to keep the session open.
31		OPCUA defines timeout both for sessions and secure channel
32		"""
33
34	1	def __init__(self, client, timeout):
35		"""
36		:param session_timeout: Timeout to re-new the session
37		in milliseconds.
38		"""
39	1	Thread.__init__(self)
40	1	self.logger = logging.getLogger(__name__)
41
42	1	self.client = client
43	1	self._dostop = False
44	1	self._cond = Condition()
45	1	self.timeout = timeout
46
47		# some server support no timeout, but we do not trust them
48	1	if self.timeout == 0:
49		self.timeout = 3600000 # 1 hour
50
51	1	def run(self):
52	1	self.logger.debug("starting keepalive thread with period of %s milliseconds", self.timeout)
53	1	server_state = self.client.get_node(ua.FourByteNodeId(ua.ObjectIds.Server_ServerStatus_State))
54	1	while not self._dostop:
55	1	with self._cond:
56	1	self._cond.wait(self.timeout / 1000)
57	1	if self._dostop:
58	1	break
59		self.logger.debug("renewing channel")
60		self.client.open_secure_channel(renew=True)
61		val = server_state.get_value()
62		self.logger.debug("server state is: %s ", val)
63	1	self.logger.debug("keepalive thread has stopped")
64
65	1	def stop(self):
66	1	self.logger.debug("stoping keepalive thread")
67	1	self._dostop = True
68	1	with self._cond:
69	1	self._cond.notify_all()
70
71
72	1	class Client(object):
73
74		"""
75		High level client to connect to an OPC-UA server.
76
77		This class makes it easy to connect and browse address space.
78		It attemps to expose as much functionality as possible
79		but if you want more flexibility it is possible and adviced to
80		use UaClient object, available as self.uaclient
81		which offers the raw OPC-UA services interface.
82		"""
83
84	1	def __init__(self, url, timeout=4):
85		"""
86
87		:param url: url of the server.
88		if you are unsure of url, write at least hostname
89		and port and call get_endpoints
90
91		:param timeout:
92		Each request sent to the server expects an answer within this
93		time. The timeout is specified in seconds.
94		"""
95	1	self.logger = logging.getLogger(__name__)
96	1	self.server_url = urlparse(url)
97		#take initial username and password from the url
98	1	self._username = self.server_url.username
99	1	self._password = self.server_url.password
100	1	self.name = "Pure Python Client"
101	1	self.description = self.name
102	1	self.application_uri = "urn:freeopcua:client"
103	1	self.product_uri = "urn:freeopcua.github.no:client"
104	1	self.security_policy = ua.SecurityPolicy()
105	1	self.secure_channel_id = None
106	1	self.secure_channel_timeout = 3600000 # 1 hour
107	1	self.session_timeout = 3600000 # 1 hour
108	1	self._policy_ids = []
109	1	self.uaclient = UaClient(timeout)
110	1	self.user_certificate = None
111	1	self.user_private_key = None
112	1	self._session_counter = 1
113	1	self.keepalive = None
114	1	self.nodes = Shortcuts(self.uaclient)
115
116	1	def __enter__(self):
117	1	self.connect()
118	1	return self
119
120	1	def __exit__(self, exc_type, exc_value, traceback):
121	1	self.disconnect()
122
123	1	@staticmethod
124		def find_endpoint(endpoints, security_mode, policy_uri):
125		"""
126		Find endpoint with required security mode and policy URI
127		"""
128	1	for ep in endpoints:
129	1	if (ep.EndpointUrl.startswith(ua.OPC_TCP_SCHEME) and
130		ep.SecurityMode == security_mode and
131		ep.SecurityPolicyUri == policy_uri):
132	1	return ep
133	1	raise ua.UaError("No matching endpoints: {0}, {1}".format(
134		security_mode, policy_uri))
135
136	1	def set_user(self, username):
137		"""
138		Set user name for the connection.
139		initial user from the URL will be overwritten
140		"""
141		self._username = username
142
143	1	def set_password(self, pwd):
144		"""
145		Set user password for the connection.
146		initial password from the URL will be overwritten
147		"""
148		self._password = pwd
149
150	1	def set_security_string(self, string):
151		"""
152		Set SecureConnection mode. String format:
153		Policy,Mode,certificate,private_key[,server_private_key]
154		where Policy is Basic128Rsa15 or Basic256,
155		Mode is Sign or SignAndEncrypt
156		certificate, private_key and server_private_key are
157		paths to .pem or .der files
158		Call this before connect()
159		"""
160	1	if not string:
161		return
162	1	parts = string.split(',')
163	1	if len(parts) < 4:
164		raise ua.UaError('Wrong format: `{0}`, expected at least 4 comma-separated values'.format(string))
165	1	policy_class = getattr(security_policies, 'SecurityPolicy' + parts[0])
166	1	mode = getattr(ua.MessageSecurityMode, parts[1])
167	1	return self.set_security(policy_class, parts[2], parts[3],
168		parts[4] if len(parts) >= 5 else None, mode)
169
170	1	def set_security(self, policy, certificate_path, private_key_path,
171		server_certificate_path=None,
172		mode=ua.MessageSecurityMode.SignAndEncrypt):
173		"""
174		Set SecureConnection mode.
175		Call this before connect()
176		"""
177	1	if server_certificate_path is None:
178		# load certificate from server's list of endpoints
179	1	endpoints = self.connect_and_get_server_endpoints()
180	1	endpoint = Client.find_endpoint(endpoints, mode, policy.URI)
181	1	server_cert = uacrypto.x509_from_der(endpoint.ServerCertificate)
182		else:
183		server_cert = uacrypto.load_certificate(server_certificate_path)
184	1	cert = uacrypto.load_certificate(certificate_path)
185	1	pk = uacrypto.load_private_key(private_key_path)
186	1	self.security_policy = policy(server_cert, cert, pk, mode)
187	1	self.uaclient.set_security(self.security_policy)
188
189	1	def load_client_certificate(self, path):
190		"""
191		load our certificate from file, either pem or der
192		"""
193		self.user_certificate = uacrypto.load_certificate(path)
194
195	1	def load_private_key(self, path):
196		"""
197		Load user private key. This is used for authenticating using certificate
198		"""
199		self.user_private_key = uacrypto.load_private_key(path)
200
201	1	def connect_and_get_server_endpoints(self):
202		"""
203		Connect, ask server for endpoints, and disconnect
204		"""
205	1	self.connect_socket()
206	1	self.send_hello()
207	1	self.open_secure_channel()
208	1	endpoints = self.get_endpoints()
209	1	self.close_secure_channel()
210	1	self.disconnect_socket()
211	1	return endpoints
212
213	1	def connect_and_find_servers(self):
214		"""
215		Connect, ask server for a list of known servers, and disconnect
216		"""
217		self.connect_socket()
218		self.send_hello()
219		self.open_secure_channel() # spec says it should not be necessary to open channel
220		servers = self.find_servers()
221		self.close_secure_channel()
222		self.disconnect_socket()
223		return servers
224
225	1	def connect_and_find_servers_on_network(self):
226		"""
227		Connect, ask server for a list of known servers on network, and disconnect
228		"""
229		self.connect_socket()
230		self.send_hello()
231		self.open_secure_channel()
232		servers = self.find_servers_on_network()
233		self.close_secure_channel()
234		self.disconnect_socket()
235		return servers
236
237	1	def connect(self):
238		"""
239		High level method
240		Connect, create and activate session
241		"""
242	1	self.connect_socket()
243	1	self.send_hello()
244	1	self.open_secure_channel()
245	1	self.create_session()
246	1	self.activate_session(username=self._username, password=self._password, certificate=self.user_certificate)
247
248	1	def disconnect(self):
249		"""
250		High level method
251		Close session, secure channel and socket
252		"""
253	1	self.close_session()
254	1	self.close_secure_channel()
255	1	self.disconnect_socket()
256
257	1	def connect_socket(self):
258		"""
259		connect to socket defined in url
260		"""
261	1	self.uaclient.connect_socket(self.server_url.hostname, self.server_url.port)
262
263	1	def disconnect_socket(self):
264	1	self.uaclient.disconnect_socket()
265
266	1	def send_hello(self):
267		"""
268		Send OPC-UA hello to server
269		"""
270	1	ack = self.uaclient.send_hello(self.server_url.geturl())
271		# FIXME check ack
272
273	1	def open_secure_channel(self, renew=False):
274		"""
275		Open secure channel, if renew is True, renew channel
276		"""
277	1	params = ua.OpenSecureChannelParameters()
278	1	params.ClientProtocolVersion = 0
279	1	params.RequestType = ua.SecurityTokenRequestType.Issue
280	1	if renew:
281		params.RequestType = ua.SecurityTokenRequestType.Renew
282	1	params.SecurityMode = self.security_policy.Mode
283	1	params.RequestedLifetime = self.secure_channel_timeout
284	1	nonce = utils.create_nonce(self.security_policy.symmetric_key_size) # length should be equal to the length of key of symmetric encryption
285	1	params.ClientNonce = nonce # this nonce is used to create a symmetric key
286	1	result = self.uaclient.open_secure_channel(params)
287	1	self.security_policy.make_symmetric_key(nonce, result.ServerNonce)
288	1	self.secure_channel_timeout = result.SecurityToken.RevisedLifetime
289
290	1	def close_secure_channel(self):
291	1	return self.uaclient.close_secure_channel()
292
293	1	def get_endpoints(self):
294	1	params = ua.GetEndpointsParameters()
295	1	params.EndpointUrl = self.server_url.geturl()
296	1	return self.uaclient.get_endpoints(params)
297
298	1	def register_server(self, server, discovery_configuration=None):
299		"""
300		register a server to discovery server
301		if discovery_configuration is provided, the newer register_server2 service call is used
302		"""
303	1	serv = ua.RegisteredServer()
304	1	serv.ServerUri = server.application_uri
305	1	serv.ProductUri = server.product_uri
306	1	serv.DiscoveryUrls = [server.endpoint.geturl()]
307	1	serv.ServerType = server.application_type
308	1	serv.ServerNames = [ua.LocalizedText(server.name)]
309	1	serv.IsOnline = True
310	1	if discovery_configuration:
311		params = ua.RegisterServer2Parameters()
312		params.Server = serv
313		params.DiscoveryConfiguration = discovery_configuration
314		return self.uaclient.register_server2(params)
315		else:
316	1	return self.uaclient.register_server(serv)
317
318	1	def find_servers(self, uris=None):
319		"""
320		send a FindServer request to the server. The answer should be a list of
321		servers the server knows about
322		A list of uris can be provided, only server having matching uris will be returned
323		"""
324	1	if uris is None:
325	1	uris = []
326	1	params = ua.FindServersParameters()
327	1	params.EndpointUrl = self.server_url.geturl()
328	1	params.ServerUris = uris
329	1	return self.uaclient.find_servers(params)
330
331	1	def find_servers_on_network(self):
332		params = ua.FindServersOnNetworkParameters()
333		return self.uaclient.find_servers_on_network(params)
334
335	1	def create_session(self):
336		"""
337		send a CreateSessionRequest to server with reasonable parameters.
338		If you want o modify settings look at code of this methods
339		and make your own
340		"""
341	1	desc = ua.ApplicationDescription()
342	1	desc.ApplicationUri = self.application_uri
343	1	desc.ProductUri = self.product_uri
344	1	desc.ApplicationName = ua.LocalizedText(self.name)
345	1	desc.ApplicationType = ua.ApplicationType.Client
346
347	1	params = ua.CreateSessionParameters()
348	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)
349	1	params.ClientNonce = nonce
350	1	params.ClientCertificate = self.security_policy.client_certificate
351	1	params.ClientDescription = desc
352	1	params.EndpointUrl = self.server_url.geturl()
353	1	params.SessionName = self.description + " Session" + str(self._session_counter)
354	1	params.RequestedSessionTimeout = 3600000
355	1	params.MaxResponseMessageSize = 0 # means no max size
356	1	response = self.uaclient.create_session(params)
357	1	if self.security_policy.client_certificate is None:
358	1	data = nonce
359		else:
360	1	data = self.security_policy.client_certificate + nonce
361	1	self.security_policy.asymmetric_cryptography.verify(data, response.ServerSignature.Signature)
362	1	self._server_nonce = response.ServerNonce
363	1	if not self.security_policy.server_certificate:
364	1	self.security_policy.server_certificate = response.ServerCertificate
365	1	elif self.security_policy.server_certificate != response.ServerCertificate:
366		raise ua.UaError("Server certificate mismatch")
367		# remember PolicyId's: we will use them in activate_session()
368	1	ep = Client.find_endpoint(response.ServerEndpoints, self.security_policy.Mode, self.security_policy.URI)
369	1	self._policy_ids = ep.UserIdentityTokens
370	1	self.session_timeout = response.RevisedSessionTimeout
371	1	self.keepalive = KeepAlive(self, min(self.session_timeout, self.secure_channel_timeout) * 0.7) # 0.7 is from spec
372	1	self.keepalive.start()
373	1	return response
374
375	1	def server_policy_id(self, token_type, default):
376		"""
377		Find PolicyId of server's UserTokenPolicy by token_type.
378		Return default if there's no matching UserTokenPolicy.
379		"""
380	1	for policy in self._policy_ids:
381	1	if policy.TokenType == token_type:
382	1	return policy.PolicyId
383		return default
384
385	1	def server_policy_uri(self, token_type):
386		"""
387		Find SecurityPolicyUri of server's UserTokenPolicy by token_type.
388		If SecurityPolicyUri is empty, use default SecurityPolicyUri
389		of the endpoint
390		"""
391	1	for policy in self._policy_ids:
392	1	if policy.TokenType == token_type:
393	1	if policy.SecurityPolicyUri:
394		return policy.SecurityPolicyUri
395		else: # empty URI means "use this endpoint's policy URI"
396	1	return self.security_policy.URI
397		return self.security_policy.URI
398
399	1	def activate_session(self, username=None, password=None, certificate=None):
400		"""
401		Activate session using either username and password or private_key
402		"""
403	1	params = ua.ActivateSessionParameters()
404	1	challenge = b""
405	1	if self.security_policy.server_certificate is not None:
406	1	challenge += self.security_policy.server_certificate
407	1	if self._server_nonce is not None:
408	1	challenge += self._server_nonce
409	1	params.ClientSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
410	1	params.ClientSignature.Signature = self.security_policy.asymmetric_cryptography.signature(challenge)
411	1	params.LocaleIds.append("en")
412	1	if not username and not certificate:
413	1	self._add_anonymous_auth(params)
414	1	elif certificate:
415		self._add_certificate_auth(params, certificate, challenge)
416		else:
417	1	self._add_user_auth(params, username, password)
418	1	return self.uaclient.activate_session(params)
419
420	1	def _add_anonymous_auth(self, params):
421	1	params.UserIdentityToken = ua.AnonymousIdentityToken()
422	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Anonymous, b"anonymous")
423
424	1	def _add_certificate_auth(self, params, certificate, challenge):
425		params.UserIdentityToken = ua.X509IdentityToken()
426		params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.Certificate, b"certificate_basic256")
427		params.UserIdentityToken.CertificateData = uacrypto.der_from_x509(certificate)
428		# specs part 4, 5.6.3.1: the data to sign is created by appending
429		# the last serverNonce to the serverCertificate
430		sig = uacrypto.sign_sha1(self.user_private_key, challenge)
431		params.UserTokenSignature = ua.SignatureData()
432		params.UserTokenSignature.Algorithm = b"http://www.w3.org/2000/09/xmldsig#rsa-sha1"
433		params.UserTokenSignature.Signature = sig
434
435	1	def _add_user_auth(self, params, username, password):
436	1	params.UserIdentityToken = ua.UserNameIdentityToken()
437	1	params.UserIdentityToken.UserName = username
438	1	policy_uri = self.server_policy_uri(ua.UserTokenType.UserName)
439	1	if not policy_uri or policy_uri == security_policies.POLICY_NONE_URI:
440		# see specs part 4, 7.36.3: if the token is NOT encrypted,
441		# then the password only contains UTF-8 encoded password
442		# and EncryptionAlgorithm is null
443	1	if self._password:
444		self.logger.warning("Sending plain-text password")
445		params.UserIdentityToken.Password = password
446	1	params.UserIdentityToken.EncryptionAlgorithm = ''
447		elif self._password:
448		data, uri = self._encrypt_password(password, policy_uri)
449		params.UserIdentityToken.Password = data
450		params.UserIdentityToken.EncryptionAlgorithm = uri
451	1	params.UserIdentityToken.PolicyId = self.server_policy_id(ua.UserTokenType.UserName, b"username_basic256")
452
453	1	def _encrypt_password(self, password, policy_uri):
454		pubkey = uacrypto.x509_from_der(self.security_policy.server_certificate).public_key()
455		# see specs part 4, 7.36.3: if the token is encrypted, password
456		# shall be converted to UTF-8 and serialized with server nonce
457		passwd = password.encode("utf8")
458		if self._server_nonce is not None:
459		passwd += self._server_nonce
460		etoken = ua.ua_binary.Primitives.Bytes.pack(passwd)
461		data, uri = security_policies.encrypt_asymmetric(pubkey, etoken, policy_uri)
462		return data, uri
463
464	1	def close_session(self):
465		"""
466		Close session
467		"""
468	1	if self.keepalive:
469	1	self.keepalive.stop()
470	1	return self.uaclient.close_session(True)
471
472	1	def get_root_node(self):
473	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.RootFolder))
474
475	1	def get_objects_node(self):
476	1	return self.get_node(ua.TwoByteNodeId(ua.ObjectIds.ObjectsFolder))
477
478	1	def get_server_node(self):
479	1	return self.get_node(ua.FourByteNodeId(ua.ObjectIds.Server))
480
481	1	def get_node(self, nodeid):
482		"""
483		Get node using NodeId object or a string representing a NodeId
484		"""
485	1	return Node(self.uaclient, nodeid)
486
487	1	def create_subscription(self, period, handler):
488		"""
489		Create a subscription.
490		returns a Subscription object which allow
491		to subscribe to events or data on server
492		handler argument is a class with data_change and/or event methods.
493		period argument is either a publishing interval in seconds or a
494		CreateSubscriptionParameters instance. The second option should be used,
495		if the opcua-server has problems with the default options.
496		These methods will be called when notfication from server are received.
497		See example-client.py.
498		Do not do expensive/slow or network operation from these methods
499		since they are called directly from receiving thread. This is a design choice,
500		start another thread if you need to do such a thing.
501		"""
502
503	1	if isinstance(period, ua.CreateSubscriptionParameters):
504		return Subscription(self.uaclient, period, handler)
505	1	params = ua.CreateSubscriptionParameters()
506	1	params.RequestedPublishingInterval = period
507	1	params.RequestedLifetimeCount = 10000
508	1	params.RequestedMaxKeepAliveCount = 3000
509	1	params.MaxNotificationsPerPublish = 10000
510	1	params.PublishingEnabled = True
511	1	params.Priority = 0
512	1	return Subscription(self.uaclient, params, handler)
513
514	1	def get_namespace_array(self):
515	1	ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
516	1	return ns_node.get_value()
517
518	1	def get_namespace_index(self, uri):
519	1	uries = self.get_namespace_array()
520	1	return uries.index(uri)
521
522	1	def delete_nodes(self, nodes, recursive=False):
523	1	return delete_nodes(self.uaclient, nodes, recursive)
524
525	1	def import_xml(self, path):
526		"""
527		Import nodes defined in xml
528		"""
529	1	importer = XmlImporter(self)
530	1	return importer.import_xml(path)
531
532	1	def export_xml(self, nodes, path):
533		"""
534		Export defined nodes to xml
535		"""
536	1	exp = XmlExporter(self)
537	1	exp.build_etree(nodes)
538	1	return exp.write_xml(path)
539
540	1	def register_namespace(self, uri):
541		"""
542		Register a new namespace. Nodes should in custom namespace, not 0.
543		This method is mainly implemented for symetry with server
544		"""
545	1	ns_node = self.get_node(ua.NodeId(ua.ObjectIds.Server_NamespaceArray))
546	1	uries = ns_node.get_value()
547	1	if uri in uries:
548	1	return uries.index(uri)
549	1	uries.append(uri)
550	1	ns_node.set_value(uries)
551	1	return len(uries) - 1
552
553
554

FreeOpcUa / python-opcua

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