Handle incoming identity key changes

This ended up turning into a rewrite/refactor of the background page.
For best results, view this diff with `-w` to ignore whitespace. In
order to support retrying message decryption, possibly at a much later
time than the message is received, we now implement the following:

Each message is saved before it is decrypted. This generates a unique
message_id which is later used to update the database entry with the
message contents, or with any errors generated during processing.

When an IncomingIdentityKeyError occurs, we catch it and save it on the
model, then update the front end as usual. When the user clicks to
accept the new key, the error is replayed, which causes the message to
be decrypted and then passed to the background page for normal
processing.

js/background.js

@@ -16,28 +16,148 @@
 
 ;(function() {
     'use strict';
+    var conversations = new Whisper.ConversationCollection();
+    var messages      = new Whisper.MessageCollection();
 
-    function init() {
     if (!localStorage.getItem('first_install_ran')) {
         localStorage.setItem('first_install_ran', 1);
         extension.navigator.tabs.create("options.html");
-        } else {
+    }
+
     if (textsecure.registration.isDone()) {
-                var conversations = new Whisper.ConversationCollection();
+        init();
-                textsecure.subscribeToPush(function(message) {
+    } else {
-                    conversations.addIncomingMessage(message).then(function(message) {
+        extension.on('registration_done', init);
-                        extension.trigger('message', message);
+    }
+
+    function init() {
+        if (!textsecure.registration.isDone()) { return; }
+
+        // initialize the socket and start listening for messages
+        var socket = textsecure.api.getMessageWebsocket();
+        new WebSocketResource(socket, function(request) {
+            // TODO: handle different types of requests. for now we only expect
+            // PUT /messages <encrypted IncomingPushMessageSignal>
+            textsecure.protocol.decryptWebsocketMessage(request.body).then(function(plaintext) {
+                var proto = textsecure.protobuf.IncomingPushMessageSignal.decode(plaintext);
+                // After this point, decoding errors are not the server's
+                // fault, and we should handle them gracefully and tell the
+                // user they received an invalid message
+                request.respond(200, 'OK');
+
+                if (proto.type === textsecure.protobuf.IncomingPushMessageSignal.Type.RECEIPT) {
+                    onDeliveryReceipt(proto);
+                } else {
+                    onMessageReceived(proto);
+                }
+
+            }).catch(function(e) {
+                console.log("Error handling incoming message:", e);
+                extension.trigger('error', e);
+                request.respond(500, 'Bad encrypted websocket message');
+            });
+        });
+    };
+
+    function onMessageReceived(pushMessage) {
+        var now = new Date().getTime();
+        var timestamp = pushMessage.timestamp.toNumber();
+
+        var conversation = conversations.add({
+            id   : pushMessage.source,
+            type : 'private'
+        }, { merge : true } );
+
+        var message = messages.add({
+            source         : pushMessage.source,
+            sourceDevice   : pushMessage.sourceDevice,
+            relay          : pushMessage.relay,
+            sent_at        : timestamp,
+            received_at    : now,
+            conversationId : pushMessage.source,
+            type           : 'incoming'
         });
-                    console.log("Got message from " + message.pushMessage.source + "." + message.pushMessage.sourceDevice +
+
-                                ': "' + getString(message.message.body) + '"');
         var newUnreadCount = textsecure.storage.getUnencrypted("unreadCount", 0) + 1;
         textsecure.storage.putUnencrypted("unreadCount", newUnreadCount);
         extension.navigator.setBadgeText(newUnreadCount);
+
+        conversation.save().then(function() {
+            message.save().then(function() {
+                return new Promise(function(resolve) {
+                    resolve(textsecure.protocol.handleIncomingPushMessageProto(pushMessage).then(
+                        function(pushMessageContent) {
+                            handlePushMessageContent(pushMessageContent, message);
+                        }
+                    ));
+                }).catch(function(e) {
+                    if (e.name === 'IncomingIdentityKeyError') {
+                        e.args.push(message.id);
+                        message.save({ errors : [e] }).then(function() {
+                            extension.trigger('message', message); // notify frontend listeners
+                        });
+                    } else {
+                        throw e;
+                    }
+                });
+            });
         });
+    };
+
+    extension.on('message:decrypted', function(options) {
+        var message = messages.add({id: options.message_id});
+        message.fetch().then(function() {
+            var pushMessageContent = handlePushMessageContent(
+                new textsecure.protobuf.PushMessageContent(options.data),
+                message
+            );
+        });
+    });
+
+    function handlePushMessageContent(pushMessageContent, message) {
+        // This function can be called from the background script on an
+        // incoming message or from the frontend after the user accepts an
+        // identity key change.
+        return textsecure.processDecrypted(pushMessageContent).then(function(pushMessageContent) {
+            var now = new Date().getTime();
+            var source = message.get('source');
+            var conversationId = pushMessageContent.group ? pushMessageContent.group.id : source;
+            var conversation = conversations.add({id: conversationId}, {merge: true});
+            conversation.fetch().always(function() {
+                var attributes = { active_at: now };
+                if (pushMessageContent.group) {
+                    attributes = {
+                        groupId    : pushMessageContent.group.id,
+                        name       : pushMessageContent.group.name,
+                        type       : 'group',
+                    };
+                } else {
+                    attributes = {
+                        name       : source,
+                        type       : 'private'
+                    };
                 }
+                conversation.set(attributes);
+
+                message.set({
+                    body           : pushMessageContent.body,
+                    conversationId : conversation.id,
+                    attachments    : pushMessageContent.attachments,
+                    decrypted_at   : now,
+                    errors         : []
+                });
+
+                conversation.save().then(function() {
+                    message.save().then(function() {
+                        extension.trigger('message', message); // notify frontend listeners
+                    });
+                });
+            });
+        });
     }
+
+    function onDeliveryReceipt(pushMessage) {
+        console.log('delivery receipt', pushMessage.source, timestamp);
     };
 
-    extension.on('registration_done', init);
-    init();
 })();

js/helpers.js

@@ -126,24 +126,28 @@ window.textsecure.throwHumanError = function(error, type, humanError) {
     throw e;
 }
 
-// message_callback({message: decryptedMessage, pushMessage: server-providedPushMessage})
+var handleAttachment = function(attachment) {
-window.textsecure.subscribeToPush = function(message_callback) {
+    function getAttachment() {
-    var socket = textsecure.api.getMessageWebsocket();
+        return textsecure.api.getAttachment(attachment.id.toString());
-
+    }
-    var resource = new WebSocketResource(socket, function(request) {
+
-        // TODO: handle different types of requests. for now we only receive
+    function decryptAttachment(encrypted) {
-        // PUT /messages <base64-encoded encrypted IncomingPushMessageSignal>
+        return textsecure.protocol.decryptAttachment(
-        textsecure.protocol.decryptWebsocketMessage(request.body).then(function(plaintext) {
+            encrypted,
-            var proto = textsecure.protobuf.IncomingPushMessageSignal.decode(plaintext);
+            attachment.key.toArrayBuffer()
-            // After this point, a) decoding errors are not the server's fault, and
+        );
-            // b) we should handle them gracefully and tell the user they received an invalid message
+    }
-            request.respond(200, 'OK');
+
-
+    function updateAttachment(data) {
-            return textsecure.protocol.handleIncomingPushMessageProto(proto).then(function(decrypted) {
+        attachment.data = data;
-                // Delivery receipt
+    }
-                if (decrypted === null)
+
-                    //TODO: Pass to UI
+    return getAttachment().
-                    return;
+      then(decryptAttachment).
+      then(updateAttachment);
+};
+
+textsecure.processDecrypted = function(decrypted) {
 
     // Now that its decrypted, validate the message and clean it up for consumer processing
     // Note that messages may (generally) only perform one action and we ignore remaining fields
@@ -155,16 +159,9 @@ window.textsecure.subscribeToPush = function(message_callback) {
     if ((decrypted.flags & textsecure.protobuf.PushMessageContent.Flags.END_SESSION)
                 == textsecure.protobuf.PushMessageContent.Flags.END_SESSION)
         return;
-                if (decrypted.flags != 0)
+    if (decrypted.flags != 0) {
         throw new Error("Unknown flags in message");
-
+    }
-                var handleAttachment = function(attachment) {
-                    return textsecure.api.getAttachment(attachment.id.toString()).then(function(encryptedBin) {
-                        return textsecure.protocol.decryptAttachment(encryptedBin, attachment.key.toArrayBuffer()).then(function(decryptedBin) {
-                            attachment.data = decryptedBin;
-                        });
-                    });
-                };
 
     var promises = [];
 
@@ -172,32 +169,38 @@ window.textsecure.subscribeToPush = function(message_callback) {
         decrypted.group.id = getString(decrypted.group.id);
         var existingGroup = textsecure.storage.groups.getNumbers(decrypted.group.id);
         if (existingGroup === undefined) {
-                        if (decrypted.group.type != textsecure.protobuf.PushMessageContent.GroupContext.Type.UPDATE)
+            if (decrypted.group.type != textsecure.protobuf.PushMessageContent.GroupContext.Type.UPDATE) {
                 throw new Error("Got message for unknown group");
+            }
             textsecure.storage.groups.createNewGroup(decrypted.group.members, decrypted.group.id);
         } else {
             var fromIndex = existingGroup.indexOf(proto.source);
 
-                        if (fromIndex < 0) //TODO: This could be indication of a race...
+            if (fromIndex < 0) {
+                //TODO: This could be indication of a race...
                 throw new Error("Sender was not a member of the group they were sending from");
+            }
 
             switch(decrypted.group.type) {
             case textsecure.protobuf.PushMessageContent.GroupContext.Type.UPDATE:
                 if (decrypted.group.avatar !== null)
                     promises.push(handleAttachment(decrypted.group.avatar));
 
-                            if (existingGroup.filter(function(number) { decrypted.group.members.indexOf(number) < 0 }).length != 0)
+                if (existingGroup.filter(function(number) { decrypted.group.members.indexOf(number) < 0 }).length != 0) {
                     throw new Error("Attempted to remove numbers from group with an UPDATE");
+                }
                 decrypted.group.added = decrypted.group.members.filter(function(number) { return existingGroup.indexOf(number) < 0; });
 
                 var newGroup = textsecure.storage.groups.addNumbers(decrypted.group.id, decrypted.group.added);
                 if (newGroup.length != decrypted.group.members.length ||
-                                        newGroup.filter(function(number) { return decrypted.group.members.indexOf(number) < 0; }).length != 0)
+                    newGroup.filter(function(number) { return decrypted.group.members.indexOf(number) < 0; }).length != 0) {
                     throw new Error("Error calculating group member difference");
+                }
 
                 //TODO: Also follow this path if avatar + name haven't changed (ie we should start storing those)
-                            if (decrypted.group.avatar === null && decrypted.group.added.length == 0 && decrypted.group.name === null)
+                if (decrypted.group.avatar === null && decrypted.group.added.length == 0 && decrypted.group.name === null) {
                     return;
+                }
 
                 //TODO: Strictly verify all numbers (ie dont let verifyNumber do any user-magic tweaking)
 
@@ -222,19 +225,13 @@ window.textsecure.subscribeToPush = function(message_callback) {
         }
     }
 
-                for (var i in decrypted.attachments)
+    for (var i in decrypted.attachments) {
         promises.push(handleAttachment(decrypted.attachments[i]));
+    }
     return Promise.all(promises).then(function() {
-                    message_callback({pushMessage: proto, message: decrypted});
+        return decrypted;
-                });
-            })
-        }).catch(function(e) {
-            // TODO: Show "Invalid message" messages?
-            console.log("Error handling incoming message: ");
-            console.log(e);
     });
-    });
+}
-};
 
 window.textsecure.registerSingleDevice = function(number, verificationCode, stepDone) {
     var signalingKey = textsecure.crypto.getRandomBytes(32 + 20);

js/protocol.js

@@ -362,9 +362,17 @@ window.textsecure.protocol = function() {
         });
     }
 
-    var wipeIdentityAndTryMessageAgain = function(from, encodedMessage) {
+    var wipeIdentityAndTryMessageAgain = function(from, encodedMessage, message_id) {
-        //TODO: Wipe identity key!
+        // Wipe identity key!
-        return handlePreKeyWhisperMessage(from, encodedMessage);
+        textsecure.storage.removeEncrypted("devices" + from.split('.')[0]);
+        return handlePreKeyWhisperMessage(from, encodedMessage).then(
+            function(pushMessageContent) {
+                extension.trigger('message:decrypted', {
+                    message_id : message_id,
+                    data       : pushMessageContent
+                });
+            }
+        );
     }
     textsecure.replay.registerFunction(wipeIdentityAndTryMessageAgain, textsecure.replay.Type.INIT_SESSION);