Treat DATA on a RST-closed stream as a connection error per RFC 9113 §5.1

java/org/apache/coyote/http2/StreamStateMachine.java

@@ -197,8 +197,10 @@ private enum State {
                             Http2Error.STREAM_CLOSED,  FrameType.PRIORITY,
                                                        FrameType.RST,
                                                        FrameType.WINDOW_UPDATE),
-        CLOSED_RST_RX      (false, false, false, false,
-                            Http2Error.STREAM_CLOSED,  FrameType.PRIORITY),
+        CLOSED_RST_RX      (false, false, false, true,
+                            Http2Error.STREAM_CLOSED,  FrameType.PRIORITY,
+                                                       FrameType.RST,
+                                                       FrameType.WINDOW_UPDATE),
         CLOSED_RST_TX      (false, false, false, false,
                             Http2Error.STREAM_CLOSED,  FrameType.DATA,
                                                        FrameType.HEADERS,

test/org/apache/coyote/http2/TestHttp2Section_5_1.java

@@ -156,29 +156,65 @@ private void doTestHalfClosedRemoteHeadersMaintainsHpackState(boolean useContinu
 
     @Test
     public void testClosedInvalidFrame01() throws Exception {
-        // HTTP2 upgrade
+        // RFC 9113, section 5.1 permits an endpoint to treat receipt of any frame other than
+        // PRIORITY, WINDOW_UPDATE, or RST_STREAM on a closed stream as a connection error of
+        // type STREAM_CLOSED. Tomcat adopts this stricter policy for the CLOSED_RST_RX state,
+        // so receiving DATA after RST_STREAM produces a GOAWAY rather than a RST_STREAM.
+
         http2Connect();
 
-        // Build the simple request
-        byte[] frameHeader = new byte[9];
-        ByteBuffer headersPayload = ByteBuffer.allocate(128);
-        buildSimpleGetRequest(frameHeader, headersPayload, null, 3);
+        // Complete a full request/response on stream 3 to drive it to CLOSED_TX,
+        // then send RST_STREAM so the server transitions to CLOSED_RST_RX.
+        sendSimpleGetRequest(3);
+        readSimpleGetResponse();
+        output.clearTrace();
 
-        // Remove the end of stream and end of headers flags
-        frameHeader[4] = 0;
+        sendRst(3, Http2Error.CANCEL.getCode());
 
-        // Process the request
-        writeFrame(frameHeader, headersPayload);
+        // DATA on a CLOSED_RST_RX stream must trigger a connection error.
+        sendData(3, new byte[] {});
 
-        // Send a rst
-        sendRst(3, Http2Error.INTERNAL_ERROR.getCode());
+        handleGoAwayResponse(3, Http2Error.STREAM_CLOSED);
+    }
 
-        // Then try sending some data (which should fail)
-        sendData(3, new byte[] {});
-        parser.readFrame();
 
-        Assert.assertTrue(output.getTrace(),
-                output.getTrace().startsWith("3-RST-[" + Http2Error.STREAM_CLOSED.getCode() + "]"));
+    @Test
+    public void testRstStreamAfterRstStreamReceived() throws Exception {
+        // RFC 9113, section 5.1: RST_STREAM on a closed stream must be silently ignored.
+        // A second RST_STREAM after the stream has entered CLOSED_RST_RX must not produce
+        // a connection error; the connection must remain open.
+        http2Connect();
+
+        sendSimpleGetRequest(3);
+        readSimpleGetResponse();
+        output.clearTrace();
+
+        sendRst(3, Http2Error.CANCEL.getCode());
+        sendRst(3, Http2Error.CANCEL.getCode());
+
+        sendSimpleGetRequest(5);
+        readSimpleGetResponse();
+        Assert.assertTrue(output.getTrace(), output.getTrace().contains(getSimpleResponseTrace(5)));
+    }
+
+
+    @Test
+    public void testWindowUpdateAfterRstStreamReceived() throws Exception {
+        // RFC 9113, section 5.1: WINDOW_UPDATE on a closed stream must be silently ignored.
+        // Receiving WINDOW_UPDATE after the stream has entered CLOSED_RST_RX must not produce
+        // a connection error; the connection must remain open.
+        http2Connect();
+
+        sendSimpleGetRequest(3);
+        readSimpleGetResponse();
+        output.clearTrace();
+
+        sendRst(3, Http2Error.CANCEL.getCode());
+        sendWindowUpdate(3, 100);
+
+        sendSimpleGetRequest(5);
+        readSimpleGetResponse();
+        Assert.assertTrue(output.getTrace(), output.getTrace().contains(getSimpleResponseTrace(5)));
     }