# HG changeset patch
# User Goffi <goffi@goffi.org>
# Date 1584982338 -3600
# Node ID e756e0eb1be4a2e06d045080b6321ae49f18073b
# Parent  109d94c62b95b6597208dc741a5796740dee4bfb
core (memory/encryption): automatic start encryption if peer send encrypted message:

If peer sends encrypted message and we have no encryption activated, we automatically
start encryption to avoid sending plain text message when answering.

markAsEncrypted now needs the encryption algorithm namespace as mandatory argument.

diff -r 109d94c62b95 -r e756e0eb1be4 sat/memory/encryption.py
--- a/sat/memory/encryption.py	Mon Mar 23 16:55:15 2020 +0100
+++ b/sat/memory/encryption.py	Mon Mar 23 17:52:18 2020 +0100
@@ -442,23 +442,38 @@
         to_jid = mess_data['to']
         encryption = self._sessions.get(to_jid.userhostJID())
         if encryption is not None:
-            if mess_data["type"] == "groupchat" and encryption['plugin'].directed:
+            plugin = encryption['plugin']
+            if mess_data["type"] == "groupchat" and plugin.directed:
                 raise exceptions.InternalError(
                 f"encryption flag must not be set for groupchat if encryption algorithm "
                 f"({encryption['plugin'].name}) is directed!")
             mess_data[C.MESS_KEY_ENCRYPTION] = encryption
-            self.markAsEncrypted(mess_data)
+            self.markAsEncrypted(mess_data, plugin.namespace)
 
     ## Misc ##
 
-    def markAsEncrypted(self, mess_data):
+    def markAsEncrypted(self, mess_data, namespace):
         """Helper method to mark a message as having been e2e encrypted.
 
         This should be used in the post_treat workflow of messageReceived trigger of
         the plugin
         @param mess_data(dict): message data as used in post treat workflow
+        @param namespace(str): namespace of the algorithm used for encrypting the message
         """
         mess_data['extra'][C.MESS_KEY_ENCRYPTED] = True
+        from_bare_jid = mess_data['from'].userhostJID()
+        if from_bare_jid != self.client.jid.userhostJID():
+            session = self.getSession(from_bare_jid)
+            if session is None:
+                # if we are currently unencrypted, we start a session automatically
+                # to avoid sending unencrypted messages in an encrypted context
+                log.info(_(
+                    "Starting e2e session with {peer_jid} as we receive encrypted "
+                    "messages")
+                    .format(peer_jid=from_bare_jid)
+                )
+                defer.ensureDeferred(self.start(from_bare_jid, namespace))
+
         return mess_data
 
     def isEncryptionRequested(self, mess_data, namespace=None):
diff -r 109d94c62b95 -r e756e0eb1be4 sat/plugins/plugin_sec_otr.py
--- a/sat/plugins/plugin_sec_otr.py	Mon Mar 23 16:55:15 2020 +0100
+++ b/sat/plugins/plugin_sec_otr.py	Mon Mar 23 17:52:18 2020 +0100
@@ -698,7 +698,7 @@
                     exceptions.CancelError("Cancelled by OTR")
                 )  # no message at all (no history, no signal)
 
-            client.encryption.markAsEncrypted(data)
+            client.encryption.markAsEncrypted(data, namespace=NS_OTR)
             trusted = otrctx.isTrusted()
 
             if trusted:
diff -r 109d94c62b95 -r e756e0eb1be4 sat/plugins/plugin_xep_0384.py
--- a/sat/plugins/plugin_xep_0384.py	Mon Mar 23 16:55:15 2020 +0100
+++ b/sat/plugins/plugin_xep_0384.py	Mon Mar 23 17:52:18 2020 +0100
@@ -1162,7 +1162,7 @@
         message_elt.children.remove(encrypted_elt)
         if plaintext:
             message_elt.addElement("body", content=plaintext)
-        post_treat.addCallback(client.encryption.markAsEncrypted)
+        post_treat.addCallback(client.encryption.markAsEncrypted, namespace=NS_OMEMO)
         defer.returnValue(True)
 
     def getJIDsForRoom(self, client, room_jid):