shared retained secrets

src/common/connection_handlers.py

@@ -1609,7 +1609,7 @@ class ConnectionHandlers(ConnectionVcard, ConnectionBytestream, ConnectionDisco,
 		del self.sessions[original_jid][thread_id]
 
 		new_jid = gajim.get_jid_without_resource(original_jid) + '/' + to_resource
-		session.jid = new_jid
+		session.jid = common.xmpp.JID(new_jid)
 
 		if not new_jid in self.sessions:
 			self.sessions[new_jid] = {}
@@ -1628,7 +1628,7 @@ returns the session that we last sent a message to.'''
 		return no_threadid_sessions[-1]
 
 	def make_new_session(self, jid, thread_id = None, type = 'chat'):
-		sess = EncryptedStanzaSession(self, jid, thread_id, type)
+		sess = EncryptedStanzaSession(self, common.xmpp.JID(jid), thread_id, type)
 
 		if not jid in self.sessions:
 			self.sessions[jid] = {}

src/common/stanza_session.py

@@ -1,4 +1,4 @@
-import gajim
+from common import gajim
 
 from common import xmpp
 from common import helpers
@@ -23,10 +23,7 @@ class StanzaSession(object):
 	def __init__(self, conn, jid, thread_id, type):
 		self.conn = conn
 
-		if isinstance(jid, str) or isinstance(jid, unicode):
+		self.jid = jid
-			self.jid = xmpp.JID(jid)
-		else:
-			self.jid = jid
 
 		self.type = type
 
@@ -543,8 +540,15 @@ class EncryptedStanzaSession(StanzaSession):
 		result.addChild(node=xmpp.DataField(name='nonce', value=base64.b64encode(self.n_o)))
 		result.addChild(node=xmpp.DataField(name='dhkeys', value=base64.b64encode(self.encode_mpi(e))))
 
-		# TODO: store and return rshashes, or at least randomly generate some
+		secrets = gajim.interface.list_secrets(self.conn.name, self.jid.getStripped()) 
-		result.addChild(node=xmpp.DataField(name='rshashes', value=[]))
+		rshashes = [self.hmac(self.n_s, rs) for rs in secrets]
+
+		# XXX add some random fake rshashes here
+
+		rshashes.sort()
+
+		rshashes = [base64.b64encode(rshash) for rshash in rshashes]
+		result.addChild(node=xmpp.DataField(name='rshashes', value=rshashes))
 
 		form_a2 = ''.join(map(lambda el: xmpp.c14n.c14n(el), result.getChildren()))
 
@@ -615,7 +619,18 @@ class EncryptedStanzaSession(StanzaSession):
 			raise exceptions.NegotiationError, 'calculated mac_a differs from received mac_a'
 
 		# 4.5.4 generating bob's final session keys
-		self.srs = ''
+
+		srs = ''
+	
+		secrets = gajim.interface.list_secrets(self.conn.name, self.jid.getStripped())
+		rshashes = [base64.b64decode(rshash) for rshash in form.getField('rshashes').getValues()]
+
+		for secret in secrets:
+			if self.hmac(self.n_o, secret) in rshashes:
+				srs = secret
+				break
+
+		# other shared secret, we haven't got one.
 		oss = ''
 
 		# check for a retained secret
@@ -623,15 +638,15 @@ class EncryptedStanzaSession(StanzaSession):
 		if self.sas_algs == 'sas28x5':
 			self.sas = self.sas_28x5(m_a, self.form_b)
 		
-		k = self.sha256(k + self.srs + oss)
+		k = self.sha256(k + srs + oss)
 
 		# XXX I can skip generating ks_o here
 		self.kc_s, self.km_s, self.ks_s = self.generate_responder_keys(k)
 		self.kc_o, self.km_o, self.ks_o = self.generate_initiator_keys(k)
 
 		# 4.5.5
-		if self.srs:
+		if srs:
-			srshash = self.hmac(self.srs, 'Shared Retained Secret')
+			srshash = self.hmac(srs, 'Shared Retained Secret')
 		else:
 			srshash = self.random_bytes(32)
 
@@ -655,11 +670,7 @@ class EncryptedStanzaSession(StanzaSession):
 
 		self.send(response)
 
-		# destroy all copies of srs
+		self.do_retained_secret(k, srs)
-
-		self.srs = self.hmac(k, 'New Retained Secret')
-
-		# destroy k
 
 		if self.negotiated['logging'] == 'mustnot':
 			self.loggable = False
@@ -668,27 +679,28 @@ class EncryptedStanzaSession(StanzaSession):
 		self.enable_encryption = True
 
 	def final_steps_alice(self, form):
-		# Alice MUST identify the shared retained secret (SRS) by selecting from her client's list of the secrets it retained from sessions with Bob's clients (the most recent secret for each of the clients he has used to negotiate ESessions with Alice's client).
-
-		# Alice does this by using each secret in the list in turn as the key to calculate the HMAC (with SHA256) of the string "Shared Retained Secret", and comparing the calculated value with the value in the 'srshash' field she received from Bob (see Sending Bob's Identity). Once she finds a match, and has confirmed that the secret has not expired (because it is older than an implementation-defined period of time), then she has found the SRS.
-
-
 		srs = ''
+		secrets = gajim.interface.list_secrets(self.conn.name, self.jid.getStripped())
+
+		srshash = base64.b64decode(form['srshash'])
+
+		for secret in secrets:
+			if self.hmac(secret, 'Shared Retained Secret') == srshash:
+				srs = secret
+				break
+
 		oss = ''
-		self.k = self.sha256(self.k + srs + oss)
+		k = self.sha256(self.k + srs + oss)
+		del self.k
 
-		# Alice MUST destroy all her copies of the old retained secret (SRS) she was keeping for Bob's client, and calculate a new retained secret for this session:
+		self.do_retained_secret(k, srs)
-
-		srs = self.hmac('New Retained Secret', self.k)
-
-		# Alice MUST securely store the new value along with the retained secrets her client shares with Bob's other clients.
 
 		# don't need to calculate ks_s here
 
-		self.kc_s, self.km_s, self.ks_s = self.generate_initiator_keys(self.k)
+		self.kc_s, self.km_s, self.ks_s = self.generate_initiator_keys(k)
-		self.kc_o, self.km_o, self.ks_o = self.generate_responder_keys(self.k) 
+		self.kc_o, self.km_o, self.ks_o = self.generate_responder_keys(k)
 
-#4.6.2 Verifying Bob's Identity
+		# 4.6.2 Verifying Bob's Identity
 
 		m_b = base64.b64decode(form['mac'])
 		id_b = base64.b64decode(form['identity'])
@@ -716,6 +728,19 @@ class EncryptedStanzaSession(StanzaSession):
 		self.status = 'active'
 		self.enable_encryption = True
 
+	# calculate and store the new retained secret
+	# prompt the user to check the remote party's identity (if necessary)
+	def do_retained_secret(self, k, srs):
+		new_srs = self.hmac(k, 'New Retained Secret')
+		account = self.conn.name
+		bjid = self.jid.getStripped()
+
+		if srs:
+			gajim.interface.replace_secret(account, bjid, srs, new_srs)
+		else:
+			self.check_identity()
+			gajim.interface.save_new_secret(account, bjid, new_srs)
+
 	# generate a random number between 'bottom' and 'top'
 	def srand(self, bottom, top):
 		# minimum number of bytes needed to represent that range
@@ -773,12 +798,12 @@ class EncryptedStanzaSession(StanzaSession):
 		self.status = None
 
 	def is_loggable(self):
-		name = self.conn.name
+		account = self.conn.name
-		no_log_for = gajim.config.get_per('accounts', name, 'no_log_for')
+		no_log_for = gajim.config.get_per('accounts', account, 'no_log_for')
 
 		if not no_log_for:
 			no_log_for = ''
 
 		no_log_for = no_log_for.split()
 
-		return self.loggable and name not in no_log_for and self.jid not in no_log_for
+		return self.loggable and account not in no_log_for and self.jid not in no_log_for

src/gajim.py

@@ -109,6 +109,8 @@ from common import exceptions
 from common.zeroconf import connection_zeroconf
 from common import dbus_support
 
+import pickle
+
 if os.name == 'posix': # dl module is Unix Only
 	try: # rename the process name to gajim
 		import dl
@@ -208,6 +210,7 @@ gajimpaths = common.configpaths.gajimpaths
 
 pid_filename = gajimpaths['PID_FILE']
 config_filename = gajimpaths['CONFIG_FILE']
+secrets_filename = gajimpaths['SECRETS_FILE']
 
 import traceback
 import errno
@@ -1390,6 +1393,46 @@ class Interface:
 			if os.path.isfile(path_to_original_file):
 				os.remove(path_to_original_file)
 
+	def list_secrets(self, account, jid):
+		f = open(secrets_filename)
+
+		try:
+			s = pickle.load(f)[account][jid]
+		except KeyError:
+			s = []
+
+		f.close()
+		return s
+
+	def save_new_secret(self, account, jid, secret):
+		f = open(secrets_filename, 'r')
+		secrets = pickle.load(f)
+		f.close()
+
+		if not account in secrets:
+			secrets[account] = {}
+
+		if not jid in secrets[account]:
+			secrets[account][jid] = []
+
+		secrets[account][jid].append(secret)
+
+		f = open(secrets_filename, 'w')
+		pickle.dump(secrets, f)
+		f.close()
+
+	def replace_secret(self, account, jid, old_secret, new_secret):
+		f = open(secrets_filename, 'r')
+		secrets = pickle.load(f)
+		f.close()
+
+		this_secrets = secrets[account][jid]
+		this_secrets[this_secrets.index(old_secret)] = new_secret
+
+		f = open(secrets_filename, 'w')
+		pickle.dump(secrets, f)
+		f.close()
+		
 	def add_event(self, account, jid, type_, event_args):
 		'''add an event to the gajim.events var'''
 		# We add it to the gajim.events queue
@@ -1727,8 +1770,6 @@ class Interface:
 					negotiated.update(ask_user)
 					session.accept_e2e_alice(form, negotiated)
 
-					negotiation.show_sas_dialog(jid, session.sas)
-
 				def reject_nondefault_options(widget):
 					session.reject_negotiation()
 					dialog.destroy()
@@ -1739,19 +1780,20 @@ class Interface:
 						on_response_no = reject_nondefault_options)
 			else:
 				session.accept_e2e_alice(form, negotiated)
-				negotiation.show_sas_dialog(jid, session.sas)
 
 			return
 		elif session.status == 'responded-e2e' and form.getType() == 'result':
+			session.check_identity = lambda: negotiation.show_sas_dialog(jid, session.sas)
+
 			try:
 				session.accept_e2e_bob(form)
 			except exceptions.NegotiationError, details: 
 				session.fail_bad_negotiation(details)
-			else:
-				negotiation.show_sas_dialog(jid, session.sas)
 
 			return
 		elif session.status == 'identified-alice' and form.getType() == 'result':
+			session.check_identity = lambda: negotiation.show_sas_dialog(jid, session.sas)
+
 			try:
 				session.final_steps_alice(form)
 			except exceptions.NegotiationError, details: 
@@ -2549,5 +2591,11 @@ if __name__ == '__main__':
 		
 	check_paths.check_and_possibly_create_paths()
 
+	# create secrets file (unless it exists)
+	if not os.path.exists(secrets_filename):
+		f = open(secrets_filename, 'w')
+		pickle.dump({}, f)
+		f.close()
+
 	Interface()
 	gtk.main()