Add fallback encryption (FallBackSessionCipher. simple DH) for when key bundle hasn't been received yet. Skip padding of bytes.

libtextsecure/message_receiver.js

@@ -646,6 +646,7 @@ MessageReceiver.prototype.extend({
       case textsecure.protobuf.Envelope.Type.CIPHERTEXT:
         window.log.info('message from', this.getEnvelopeId(envelope));
         promise = Promise.resolve(ciphertext.toArrayBuffer())//;sessionCipher
+          // TODO: restore decryption & unpadding
           //.decryptWhisperMessage(ciphertext)
           //.then(this.unpad);
         break;

libtextsecure/outgoing_message.js

@@ -28,6 +28,7 @@ function OutgoingMessage(
   this.numbersCompleted = 0;
   this.errors = [];
   this.successfulNumbers = [];
+  this.fallBackEncryption = false;
 }
 
 OutgoingMessage.prototype = {
@@ -63,11 +64,12 @@ OutgoingMessage.prototype = {
     return () =>
       textsecure.storage.protocol.getDeviceIds(number).then(deviceIds => {
         if (deviceIds.length === 0) {
-          return this.registerError(
-            number,
-            'Got empty device list when loading device keys',
-            null
-          );
+          deviceIds = [1];
+          // return this.registerError(
+          //   number,
+          //   'Got empty device list when loading device keys',
+          //   null
+          // );
         }
         return this.doSendMessage(number, deviceIds, recurse);
       });
@@ -110,7 +112,7 @@ OutgoingMessage.prototype = {
           return null;
         })
       );
-
+    // TODO: check if still applicable
     if (updateDevices === undefined) {
       return this.server.getKeysForNumber(number).then(handleResult);
     }
@@ -124,6 +126,8 @@ OutgoingMessage.prototype = {
           const [preKey, signedPreKey] = keys;
           if (preKey == undefined || signedPreKey == undefined) {
             log.error("Will need to request keys!")
+            this.fallBackEncryption = true;
+            return Promise.resolve();
           }
           else {
             const identityKey = StringView.hexToArrayBuffer(number);
@@ -186,11 +190,13 @@ OutgoingMessage.prototype = {
   getPlaintext() {
     if (!this.plaintext) {
       const messageBuffer = this.message.toArrayBuffer();
-      this.plaintext = new Uint8Array(
-        this.getPaddedMessageLength(messageBuffer.byteLength + 1) - 1
-      );
+      this.plaintext = new Uint8Array(messageBuffer.byteLength);
+      // TODO: figure out why we needed padding in the first place
+      // this.plaintext = new Uint8Array(
+      //   this.getPaddedMessageLength(messageBuffer.byteLength + 1) - 1
+      // );
       this.plaintext.set(new Uint8Array(messageBuffer));
-      this.plaintext[messageBuffer.byteLength] = 0x80;
+      //this.plaintext[messageBuffer.byteLength] = 0x80;
     }
     return this.plaintext;
   },
@@ -211,11 +217,43 @@ OutgoingMessage.prototype = {
           options.messageKeysLimit = false;
         }
 
-        const sessionCipher = new libsignal.SessionCipher(
+        let sessionCipher;
+        if (this.fallBackEncryption) {
+          // TODO: move to own file?
+          FallBackSessionCipher = function (address) {
+            this.recipientPubKey = StringView.hexToArrayBuffer(address.getName());
+            this.encrypt = async (plaintext) => {
+              const myKeyPair = await textsecure.storage.protocol.getIdentityKeyPair();
+              const myPrivateKey = myKeyPair.privKey;
+              const symmetricKey = libsignal.Curve.calculateAgreement(this.recipientPubKey, myPrivateKey);
+              const iv = libsignal.crypto.getRandomBytes(16);
+              const ciphertext = await libsignal.crypto.encrypt(symmetricKey, plaintext, iv);
+              const ivAndCiphertext = new Uint8Array(
+                iv.byteLength + ciphertext.byteLength
+              );
+              ivAndCiphertext.set(new Uint8Array(iv));
+              ivAndCiphertext.set(
+                new Uint8Array(ciphertext),
+                iv.byteLength
+              );
+
+              return {
+                  type           : 6, //friend request
+                  body           : new dcodeIO.ByteBuffer.wrap(ivAndCiphertext).toString('binary'),
+                  registrationId : null
+              };
+            }
+          }
+          sessionCipher = new FallBackSessionCipher(
+            address
+          );
+        } else {
+          sessionCipher = new libsignal.SessionCipher(
             textsecure.storage.protocol,
             address,
             options
           );
+        }
         ciphers[address.getDeviceId()] = sessionCipher;
         return sessionCipher.encrypt(plaintext).then(ciphertext => ({
           type: ciphertext.type,

protos/SignalService.proto

@@ -11,6 +11,7 @@ message Envelope {
     KEY_EXCHANGE  = 2;
     PREKEY_BUNDLE = 3;
     RECEIPT       = 5;
+    FRIEND_REQUEST = 6;
   }
 
   optional Type   type          = 1;