Strict handling of connection error

Following cases are now treated as connection error of type
PROTOCOL_ERROR.

* Receiving HEADERS from client in reserved (local)
* Receiving PUSH_PROMISE against peer-initiated stream
* Receiving WINDOW_UPDATE against in reserved (local, remote)

lib/nghttp2_session.c

@@ -1807,6 +1807,10 @@ int nghttp2_session_on_headers_received(nghttp2_session *session,
         }
       }
     }
+  } else if(stream->state == NGHTTP2_STREAM_RESERVED) {
+    /* reserved (local) */
+    return nghttp2_session_handle_invalid_connection(session, frame,
+                                                     NGHTTP2_PROTOCOL_ERROR);
   } else {
     /* half closed (remote): from the spec:
 
@@ -2162,6 +2166,10 @@ int nghttp2_session_on_push_promise_received(nghttp2_session *session,
   session->last_recv_stream_id = frame->push_promise.promised_stream_id;
   stream = nghttp2_session_get_stream(session, frame->hd.stream_id);
   if(stream) {
+    if(!nghttp2_session_is_my_stream_id(session, frame->hd.stream_id)) {
+      return nghttp2_session_handle_invalid_connection(session, frame,
+                                                       NGHTTP2_PROTOCOL_ERROR);
+    }
     if((stream->shut_flags & NGHTTP2_SHUT_RD) == 0) {
       if(stream->state == NGHTTP2_STREAM_CLOSING) {
         return nghttp2_session_add_rst_stream
@@ -2293,6 +2301,10 @@ int nghttp2_session_on_window_update_received(nghttp2_session *session,
     nghttp2_stream *stream;
     stream = nghttp2_session_get_stream(session, frame->hd.stream_id);
     if(stream) {
+      if(stream->state == NGHTTP2_STREAM_RESERVED) {
+        return nghttp2_session_handle_invalid_connection
+          (session, frame, NGHTTP2_PROTOCOL_ERROR);
+      }
       if(stream->remote_flow_control == 0) {
         /* Same reason with connection-level flow control */
         nghttp2_session_call_on_frame_received(session, frame);

tests/nghttp2_session_test.c

@@ -1043,7 +1043,7 @@ void test_nghttp2_session_on_push_promise_received(void)
   /* After GOAWAY, PUSH_PROMISE will be discarded */
   frame.push_promise.promised_stream_id = 10;
 
- user_data.frame_recv_cb_called = 0;
+  user_data.frame_recv_cb_called = 0;
   user_data.invalid_frame_recv_cb_called = 0;
   CU_ASSERT(0 == nghttp2_session_on_push_promise_received(session, &frame));
 
@@ -1053,6 +1053,25 @@ void test_nghttp2_session_on_push_promise_received(void)
 
   nghttp2_frame_push_promise_free(&frame.push_promise);
   nghttp2_session_del(session);
+
+  nghttp2_session_client_new(&session, &callbacks, &user_data);
+  stream = nghttp2_session_open_stream(session, 2, NGHTTP2_FLAG_NONE,
+                                       NGHTTP2_PRI_DEFAULT,
+                                       NGHTTP2_STREAM_RESERVED, NULL);
+  nvlen = nghttp2_nv_array_from_cstr(&nva, nv);
+  /* Attempt to PUSH_PROMISE against reserved (remote) stream */
+  nghttp2_frame_push_promise_init(&frame.push_promise,
+                                  NGHTTP2_FLAG_END_PUSH_PROMISE, 2, 4,
+                                  nva, nvlen);
+
+  user_data.frame_recv_cb_called = 0;
+  user_data.invalid_frame_recv_cb_called = 0;
+  CU_ASSERT(0 == nghttp2_session_on_push_promise_received(session, &frame));
+
+  CU_ASSERT(0 == user_data.frame_recv_cb_called);
+  CU_ASSERT(1 == user_data.invalid_frame_recv_cb_called);
+
+  nghttp2_session_del(session);
 }
 
 void test_nghttp2_session_on_ping_received(void)