fix(push): close E2EE-flip race by re-checking room encryption at reply send time, pre-flight credentials before optimistic echo, share callId-dedup helpers between FCM and Worker

android/app/src/main/java/chat/vojo/app/ReplyReceiver.java

@@ -12,6 +12,7 @@ import androidx.core.app.NotificationCompat;
 import androidx.core.app.RemoteInput;
 
 import org.json.JSONObject;
+import org.json.JSONException;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -88,12 +89,11 @@ public class ReplyReceiver extends BroadcastReceiver {
 
         final Context appContext = context.getApplicationContext();
 
-        // Optimistic local echo — appends a self-Person message to the
+        // Pre-flight validation BEFORE the optimistic echo. Posting a self
-        // conversation and re-posts, so the user sees their reply in the
+        // bubble first and then immediately stacking an error notif on top
-        // shade before the HTTP completes.
+        // is jarring UX; for predictable failures (logged out, freshly
-        long now = System.currentTimeMillis();
+        // encrypted room) we'd rather skip the echo and only surface the
-        VojoFirebaseMessagingService.appendOutgoingMessage(appContext, roomId, text, now);
+        // error.
-
         final SharedPreferences prefs = appContext.getSharedPreferences(
             VojoPollWorker.PREFS, Context.MODE_PRIVATE);
         final String token = prefs.getString(VojoPollWorker.KEY_ACCESS_TOKEN, null);
@@ -104,6 +104,28 @@ public class ReplyReceiver extends BroadcastReceiver {
             return;
         }
 
+        // Race guard for E2EE flip: the per-room metadata snapshot is
+        // refreshed by JS on m.room.encryption Timeline events, but a push
+        // delivered in the narrow window between the encryption state
+        // landing and the dump completing could still expose the reply
+        // action on a freshly-encrypted room. Re-read the snapshot
+        // synchronously here — Synapse does NOT enforce "no cleartext in
+        // encrypted rooms" at the spec level, so without this guard we'd
+        // leak the user's reply into an E2EE timeline as plaintext.
+        if (isRoomEncryptedAtSendTime(prefs, roomId)) {
+            Log.w(TAG, "onReceive: room flipped to encrypted between render and send, abort");
+            postReplyError(appContext, roomId);
+            return;
+        }
+
+        // Optimistic local echo — appends a self-Person message to the
+        // conversation and re-posts, so the user sees their reply in the
+        // shade before the HTTP completes. Only happens after pre-flight
+        // checks pass so the user doesn't see an echo for a reply we know
+        // will fail.
+        long now = System.currentTimeMillis();
+        VojoFirebaseMessagingService.appendOutgoingMessage(appContext, roomId, text, now);
+
         final PendingResult pendingResult = goAsync();
         final String txnId = "vojo-reply-" + UUID.randomUUID();
         EXECUTOR.execute(() -> {
@@ -180,7 +202,7 @@ public class ReplyReceiver extends BroadcastReceiver {
             ctx.getSystemService(Context.NOTIFICATION_SERVICE);
         if (nm == null) return;
         try {
-            String channel = VojoFirebaseMessagingService.CHANNEL_ID_DM_PUBLIC;
+            String channel = VojoFirebaseMessagingService.CHANNEL_ID_DM;
             NotificationCompat.Builder b = new NotificationCompat.Builder(ctx, channel)
                 .setSmallIcon(R.mipmap.ic_launcher)
                 .setContentTitle(PushStrings.replyFailed(ctx))
@@ -197,4 +219,30 @@ public class ReplyReceiver extends BroadcastReceiver {
     private static String trimTrailingSlash(String s) {
         return (s != null && s.endsWith("/")) ? s.substring(0, s.length() - 1) : s;
     }
+
+    /**
+     * Synchronous re-check of the room's encryption flag at send time.
+     * Mirrors VojoFirebaseMessagingService.loadRoomMetadata's tolerant
+     * parse: legacy string-shape entries and missing flags both default
+     * to encrypted=true (privacy-first — refusing a reply on a falsely-
+     * flagged room is harmless; sending cleartext into a truly encrypted
+     * room is a privacy leak).
+     */
+    private static boolean isRoomEncryptedAtSendTime(SharedPreferences prefs, String roomId) {
+        String raw = prefs.getString(VojoPollWorker.KEY_ROOM_NAMES, null);
+        if (raw == null || raw.isEmpty()) return true;
+        try {
+            JSONObject map = new JSONObject(raw);
+            if (!map.has(roomId) || map.isNull(roomId)) return true;
+            JSONObject obj = map.optJSONObject(roomId);
+            if (obj == null) {
+                // Legacy string-shape predates the encryption flag —
+                // assume encrypted to err on the side of privacy.
+                return true;
+            }
+            return obj.optBoolean("isEncrypted", true);
+        } catch (JSONException je) {
+            return true;
+        }
+    }
 }

android/app/src/main/java/chat/vojo/app/VojoFirebaseMessagingService.java

@@ -66,12 +66,11 @@ public class VojoFirebaseMessagingService extends MessagingService {
     // after creation on API 26+, so any future config change (sound, vibration
     // pattern) bumps the version.
     private static final String MESSAGE_CHANNEL_GROUP_ID = "vojo_messages_v1";
-    private static final String CHANNEL_ID_DM = "vojo_messages_dm_v1";
+    // Package-visible: ReplyReceiver reuses CHANNEL_ID_DM for its "reply
+    // failed" one-shot notification. Was previously a separate _PUBLIC
+    // alias; collapsed to a single package-private constant.
+    static final String CHANNEL_ID_DM = "vojo_messages_dm_v1";
     private static final String CHANNEL_ID_GROUP = "vojo_messages_group_v1";
-    // Package-visible mirror of CHANNEL_ID_DM so ReplyReceiver can post its
-    // one-shot "reply failed" error notification on the same channel without
-    // duplicating the literal.
-    static final String CHANNEL_ID_DM_PUBLIC = CHANNEL_ID_DM;
 
     private static final String GROUP_KEY = "vojo_messages";
     // NotificationChannel settings (vibration pattern, sound, importance) are
@@ -105,8 +104,12 @@ public class VojoFirebaseMessagingService extends MessagingService {
      * m.rtc.notification events that share the parent — re-ring for
      * participant rejoin, FCM retry-with-fresh-event-id — see the mark and
      * silently skip the post.
+     *
+     * Package-private so VojoPollWorker can build the same key shape from
+     * its flatten path without duplicating the literal — keeps the FCM and
+     * polling paths trivially in sync.
      */
-    private static String compositeCallDedupKey(String roomId, String callSessionId) {
+    static String compositeCallDedupKey(String roomId, String callSessionId) {
         return "call:" + roomId + ":" + callSessionId;
     }
 
@@ -121,8 +124,12 @@ public class VojoFirebaseMessagingService extends MessagingService {
      * deployment config. We probe both shapes — and `content_call_id` as
      * a third candidate for legacy MSC2746 calls — so the dedup works
      * regardless of which encoding the homeserver's Sygnal happens to use.
+     *
+     * Package-private: VojoPollWorker's flatten path writes the
+     * `content_m.relates_to_event_id` form, so this same helper resolves
+     * both FCM and polling payloads.
      */
-    private static String extractCallSessionId(Map<String, String> data) {
+    static String extractCallSessionId(Map<String, String> data) {
         String[] candidates = new String[] {
             "content_m.relates_to_event_id",
             "content_m_relates_to_event_id",

android/app/src/main/java/chat/vojo/app/VojoPollWorker.java

@@ -291,13 +291,16 @@ public class VojoPollWorker extends Worker {
                             // missed-call. Without this, a session with one
                             // FCM live-alert ring + one re-ring through
                             // polling would surface as both a CallStyle and
-                            // a missed-call card.
+                            // a missed-call card. Helpers live in
+                            // VojoFirebaseMessagingService so the key shape
+                            // stays in lock-step across FCM and polling.
                             String roomIdField = flattened.get("room_id");
-                            String sessionId = flattened.get("content_m.relates_to_event_id");
+                            String sessionId = VojoFirebaseMessagingService
-                            if (sessionId == null) sessionId = flattened.get("content_call_id");
+                                .extractCallSessionId(flattened);
+                            String composite = null;
                             if (roomIdField != null && sessionId != null) {
-                                String composite =
+                                composite = VojoFirebaseMessagingService
-                                    "call:" + roomIdField + ":" + sessionId;
+                                    .compositeCallDedupKey(roomIdField, sessionId);
                                 if (NotificationDedup.wasNotified(ctx, composite)) {
                                     if (ts > highestTsSeen) highestTsSeen = ts;
                                     treatAsNotRenderable = true;
@@ -311,12 +314,11 @@ public class VojoPollWorker extends Worker {
                                 // CallStyle.
                                 posted = VojoFirebaseMessagingService
                                     .renderMissedCallNotification(ctx, flattened);
-                                if (posted && roomIdField != null && sessionId != null) {
+                                if (posted && composite != null) {
                                     // Mark the composite so the next polling
                                     // cycle observing a re-ring for the same
                                     // session doesn't double-post.
-                                    NotificationDedup.markNotified(ctx,
+                                    NotificationDedup.markNotified(ctx, composite);
-                                        "call:" + roomIdField + ":" + sessionId);
                                 }
                             }
                         } else if (isRtcType) {