fix(firestore): honor appName in getSession/deleteSession/listEvents

contrib/firestore-session-service/src/main/java/com/google/adk/sessions/FirestoreSessionService.java

@@ -177,6 +177,16 @@ public Maybe<Session> getSession(
                 return Maybe.empty();
               }
 
+              // Enforce the (appName, userId, sessionId) scope. The Firestore
+              // document is keyed only by (userId, sessionId), so without this
+              // check a caller could read a session that belongs to a different
+              // application for the same user. Treat an appName mismatch as
+              // "not found" so cross-application existence is not leaked.
+              if (!appName.equals(data.get(APP_NAME_KEY))) {
+                logger.warn("Session {} does not belong to app {}", sessionId, appName);
+                return Maybe.error(new SessionNotFoundException("Session not found: " + sessionId));
+              }
+
               // Fetch events based on config
               GetSessionConfig config =
                   configOpt.orElseGet(() -> GetSessionConfig.builder().build());
@@ -491,6 +501,16 @@ public Completable deleteSession(String appName, String userId, String sessionId
           com.google.cloud.firestore.DocumentReference sessionRef =
               getSessionsCollection(userId).document(sessionId);
 
+          // Enforce the (appName, userId, sessionId) scope before deleting.
+          // The document is keyed only by (userId, sessionId), so without this
+          // check a caller could delete a session that belongs to a different
+          // application for the same user.
+          DocumentSnapshot sessionDoc = sessionRef.get().get();
+          if (!sessionDoc.exists() || !appName.equals(sessionDoc.get(APP_NAME_KEY))) {
+            logger.warn("Session {} not found for app {}; nothing to delete", sessionId, appName);
+            return;
+          }
+
           // 1. Fetch all events in the subcollection to delete them in batches.
           CollectionReference eventsRef = sessionRef.collection(EVENTS_SUBCOLLECTION_NAME);
           com.google.api.core.ApiFuture<com.google.cloud.firestore.QuerySnapshot> eventsQuery =
@@ -536,9 +556,11 @@ public Single<ListEventsResponse> listEvents(String appName, String userId, Stri
               getSessionsCollection(userId).document(sessionId).get();
           DocumentSnapshot sessionDocument = sessionFuture.get(); // Block for the result
 
-          if (!sessionDocument.exists()) {
+          if (!sessionDocument.exists() || !appName.equals(sessionDocument.get(APP_NAME_KEY))) {
             logger.warn(
-                "Session not found for sessionId: {}. Returning empty list of events.", sessionId);
+                "Session not found for sessionId: {} in app {}. Returning empty list of events.",
+                sessionId,
+                appName);
             throw new SessionNotFoundException(appName + "," + userId + "," + sessionId);
           }
 

contrib/firestore-session-service/src/test/java/com/google/adk/sessions/FirestoreSessionServiceTest.java

@@ -273,7 +273,8 @@ void getSession_withAfterTimestamp_appliesFilterToQuery() {
     when(mockSessionDocRef.get()).thenReturn(ApiFutures.immediateFuture(mockSessionSnapshot));
     when(mockSessionSnapshot.exists()).thenReturn(true);
     when(mockSessionSnapshot.getReference()).thenReturn(mockSessionDocRef);
-    when(mockSessionSnapshot.getData()).thenReturn(ImmutableMap.of("state", Map.of()));
+    when(mockSessionSnapshot.getData())
+        .thenReturn(ImmutableMap.of(Constants.KEY_APP_NAME, APP_NAME, "state", Map.of()));
     when(mockQuery.whereGreaterThan(Constants.KEY_TIMESTAMP, timestamp.toString()))
         .thenReturn(mockQuery);
     when(mockQuery.get()).thenReturn(ApiFutures.immediateFuture(mockQuerySnapshot));
@@ -778,6 +779,7 @@ void listEvents_sessionExists_returnsEvents() {
     when(mockSessionsCollection.document(SESSION_ID)).thenReturn(mockSessionDocRef);
     when(mockSessionDocRef.get()).thenReturn(ApiFutures.immediateFuture(mockSessionSnapshot));
     when(mockSessionSnapshot.exists()).thenReturn(true);
+    when(mockSessionSnapshot.get(Constants.KEY_APP_NAME)).thenReturn(APP_NAME);
     when(mockSessionSnapshot.getReference()).thenReturn(mockSessionDocRef);
     when(mockQuery.get()).thenReturn(ApiFutures.immediateFuture(mockQuerySnapshot));
     Map<String, Object> eventData =
@@ -828,6 +830,10 @@ void listEvents_sessionDoesNotExist_throwsException() {
   void deleteSession_deletesEventsAndSession() {
     // Arrange
     when(mockSessionsCollection.document(SESSION_ID)).thenReturn(mockSessionDocRef);
+    // The ownership check fetches the session document first.
+    when(mockSessionDocRef.get()).thenReturn(ApiFutures.immediateFuture(mockSessionSnapshot));
+    when(mockSessionSnapshot.exists()).thenReturn(true);
+    when(mockSessionSnapshot.get(Constants.KEY_APP_NAME)).thenReturn(APP_NAME);
     when(mockSessionDocRef.collection(Constants.EVENTS_SUBCOLLECTION_NAME))
         .thenReturn(mockEventsCollection);
     when(mockEventsCollection.get()).thenReturn(ApiFutures.immediateFuture(mockQuerySnapshot));
@@ -901,4 +907,75 @@ void listSessions_returnsListOfSessions() {
           return true;
         });
   }
+
+  // --- appName scope enforcement tests ---
+  // Sessions are keyed by (userId, sessionId) only, so getSession, deleteSession and listEvents
+  // must reject a request whose appName does not match the stored session's appName; otherwise one
+  // application could read, list the events of, or delete another application's session for the
+  // same user.
+
+  /** Tests that getSession emits an error when the stored appName does not match the request. */
+  @Test
+  void getSession_appNameMismatch_emitsError() {
+    // Arrange
+    when(mockSessionsCollection.document(SESSION_ID)).thenReturn(mockSessionDocRef);
+    when(mockSessionDocRef.get()).thenReturn(ApiFutures.immediateFuture(mockSessionSnapshot));
+    when(mockSessionSnapshot.exists()).thenReturn(true);
+    when(mockSessionSnapshot.getData())
+        .thenReturn(
+            ImmutableMap.of(
+                "id",
+                SESSION_ID,
+                Constants.KEY_APP_NAME,
+                "other-app",
+                "userId",
+                USER_ID,
+                "updateTime",
+                NOW.toString(),
+                "state",
+                Collections.emptyMap()));
+
+    // Act
+    TestObserver<Session> testObserver =
+        sessionService.getSession(APP_NAME, USER_ID, SESSION_ID, Optional.empty()).test();
+
+    // Assert
+    testObserver.assertError(SessionNotFoundException.class);
+  }
+
+  /** Tests that listEvents emits an error when the stored appName does not match the request. */
+  @Test
+  void listEvents_appNameMismatch_emitsError() {
+    // Arrange
+    when(mockSessionsCollection.document(SESSION_ID)).thenReturn(mockSessionDocRef);
+    when(mockSessionDocRef.get()).thenReturn(ApiFutures.immediateFuture(mockSessionSnapshot));
+    when(mockSessionSnapshot.exists()).thenReturn(true);
+    when(mockSessionSnapshot.get(Constants.KEY_APP_NAME)).thenReturn("other-app");
+
+    // Act
+    TestObserver<ListEventsResponse> testObserver =
+        sessionService.listEvents(APP_NAME, USER_ID, SESSION_ID).test();
+
+    // Assert
+    testObserver.assertError(SessionNotFoundException.class);
+  }
+
+  /**
+   * Tests that deleteSession does not delete when the stored appName does not match the request.
+   */
+  @Test
+  void deleteSession_appNameMismatch_doesNotDelete() {
+    // Arrange
+    when(mockSessionsCollection.document(SESSION_ID)).thenReturn(mockSessionDocRef);
+    when(mockSessionDocRef.get()).thenReturn(ApiFutures.immediateFuture(mockSessionSnapshot));
+    when(mockSessionSnapshot.exists()).thenReturn(true);
+    when(mockSessionSnapshot.get(Constants.KEY_APP_NAME)).thenReturn("other-app");
+
+    // Act
+    sessionService.deleteSession(APP_NAME, USER_ID, SESSION_ID).test().assertComplete();
+
+    // Assert: the session (belonging to another app) must be left intact.
+    verify(mockSessionDocRef, never()).delete();
+    verify(mockWriteBatch, never()).commit();
+  }
 }