Merge pull request #179 from matrix-org/rav/send_megolm_keys

Send out megolm keys when we start a megolm session

lib/crypto-algorithms/base.js

@@ -50,12 +50,14 @@ module.exports.DECRYPTION_CLASSES = {};
  * @param {string} params.deviceId The identifier for this device.
  * @param {module:crypto} params.crypto crypto core
  * @param {module:OlmDevice} params.olmDevice olm.js wrapper
+ * @param {module:base-apis~MatrixBaseApis} baseApis base matrix api interface
  * @param {string} params.roomId  The ID of the room we will be sending to
  */
 var EncryptionAlgorithm = function(params) {
     this._deviceId = params.deviceId;
     this._crypto = params.crypto;
     this._olmDevice = params.olmDevice;
+    this._baseApis = params.baseApis;
     this._roomId = params.roomId;
 };
 /** */
@@ -81,7 +83,7 @@ EncryptionAlgorithm.prototype.initRoomEncryption = function(roomMembers) {
  * @method module:crypto-algorithms/base.EncryptionAlgorithm#encryptMessage
  * @abstract
  *
- * @param {module:models/room?} room
+ * @param {module:models/room} room
  * @param {string} eventType
  * @param {object} plaintext event content
  *

lib/crypto-algorithms/megolm.js

@@ -46,10 +46,12 @@ utils.inherits(MegolmEncryption, base.EncryptionAlgorithm);
 /**
  * @private
  *
+ * @param {module:models/room} room
+ *
  * @return {module:client.Promise} Promise which resolves when setup is
  *   complete.
  */
-MegolmEncryption.prototype._ensureOutboundSession = function() {
+MegolmEncryption.prototype._ensureOutboundSession = function(room) {
     if (this._prepPromise) {
         // prep already in progress
         return this._prepPromise;
@@ -61,8 +63,6 @@ MegolmEncryption.prototype._ensureOutboundSession = function() {
     }
 
     var session_id = this._olmDevice.createOutboundGroupSession();
-    this._outboundSessionId = session_id;
-
     var key = this._olmDevice.getOutboundGroupSessionKey(session_id);
 
     console.log(
@@ -80,20 +80,94 @@ MegolmEncryption.prototype._ensureOutboundSession = function() {
         key.key, key.chain_index
     );
 
+    // send the keys to each (unblocked) device in the room.
+    var payload = {
+        type: "m.room_key",
+        content: {
+            algorithm: olmlib.MEGOLM_ALGORITHM,
+            room_id: this._roomId,
+            session_id: session_id,
+            session_key: key.key,
+            chain_index: key.chain_index,
+        }
+    };
+
+    var roomMembers = utils.map(room.getJoinedMembers(), function(u) {
+        return u.userId;
+    });
+
     var self = this;
-    // TODO: initiate key-sharing
+    var txnBase = '' + (new Date().getTime()) + '.';
-    this._prepPromise = q.delay(3000).then(function() {
+    var txnCtr = 0;
-        console.log("woop woop, we totally shared the keys");
+
+    // TODO: we need to give the user a chance to block any devices or users
+    // before we send them the keys; it's too late to download them here.
+    this._prepPromise = this._crypto.downloadKeys(
+        roomMembers, false
+    ).then(function(res) {
+        return self._crypto.ensureOlmSessionsForUsers(roomMembers);
+    }).then(function(devicemap) {
+        var promises = [];
+        for (var userId in devicemap) {
+            if (!devicemap.hasOwnProperty(userId)) {
+                continue;
+            }
+
+            var devices = devicemap[userId];
+
+            for (var deviceId in devices) {
+                if (!devices.hasOwnProperty(deviceId)) {
+                    continue;
+                }
+
+                var deviceInfo = devices[deviceId].device;
+                var encryptedContent = olmlib.encryptMessageForDevices(
+                    self._deviceId,
+                    self._olmDevice,
+                    [deviceInfo.getIdentityKey()],
+                    payload
+                );
+
+                var txnId = txnBase + (txnCtr++);
+
+                // TODO: send an OOB message. for now, send an in-band message.
+
+                // TODO: aggregate the messages into batches. If we make a
+                // separate request for each message, we will get rate-limited.
+                // On the other hand, we can't just send them in one big batch,
+                // because we'll hit the event size limit.
+
+                var path = utils.encodeUri(
+                    "/rooms/$roomId/send/m.room.encrypted/$txnId", {
+                        $roomId: self._roomId,
+                        $txnId: txnId,
+                    }
+                );
+
+                // TODO: retries
+                var promise = self._baseApis._http.authedRequest(
+                    undefined, "PUT", path, undefined, encryptedContent
+                );
+
+                promises.push(promise);
+            }
+        }
+        return q.all(promises);
+    }).then(function() {
+        // don't set this until the keys are sent successfully; if we get an
+        // error, the user can restart by resending the message.
+        self._outboundSessionId = session_id;
+    }).finally(function() {
         self._prepPromise = null;
     });
+
     return this._prepPromise;
 };
 
-
 /**
  * @inheritdoc
  *
- * @param {module:models/room?} room
+ * @param {module:models/room} room
  * @param {string} eventType
  * @param {object} plaintext event content
  *
@@ -101,7 +175,7 @@ MegolmEncryption.prototype._ensureOutboundSession = function() {
  */
 MegolmEncryption.prototype.encryptMessage = function(room, eventType, content) {
     var self = this;
-    return this._ensureOutboundSession().then(function() {
+    return this._ensureOutboundSession(room).then(function() {
         var payloadJson = {
             room_id: self._roomId,
             type: eventType,

lib/crypto-algorithms/olm.js

@@ -56,17 +56,13 @@ OlmEncryption.prototype.initRoomEncryption = function(roomMembers) {
 /**
  * @inheritdoc
  *
- * @param {module:models/room?} room
+ * @param {module:models/room} room
  * @param {string} eventType
  * @param {object} plaintext event content
  *
  * @return {module:client.Promise} Promise which resolves to the new event body
  */
 OlmEncryption.prototype.encryptMessage = function(room, eventType, content) {
-    if (!room) {
-        throw new Error("Cannot send encrypted messages in unknown rooms");
-    }
-
     // pick the list of recipients based on the membership list.
     //
     // TODO: there is a race condition here! What if a new user turns up

lib/crypto.js

@@ -540,6 +540,7 @@ Crypto.prototype.setRoomEncryption = function(roomId, config, roomMembers) {
         deviceId: this._deviceId,
         crypto: this,
         olmDevice: this._olmDevice,
+        baseApis: this._baseApis,
         roomId: roomId,
     });
     this._roomAlgorithms[roomId] = alg;
@@ -678,6 +679,10 @@ Crypto.prototype.encryptEventIfNeeded = function(event, room) {
         return null;
     }
 
+    if (!room) {
+        throw new Error("Cannot send encrypted messages in unknown rooms");
+    }
+
     var roomId = event.getRoomId();
 
     var alg = this._roomAlgorithms[roomId];