netty: Include pseudo-headers in GrpcHttp2RequestHeaders.iterator() (v1.83.x backport) (#13122)

Backport of #13118 to v1.83.x.
---
fixes b/556157371

Author: AgraVator

netty/src/main/java/io/grpc/netty/GrpcHttp2HeadersUtils.java

@@ -306,13 +306,18 @@ protected static void appendNameAndValue(StringBuilder builder, CharSequence nam
 
     private List<Map.Entry<CharSequence, CharSequence>> namesAndValuesToImmutableList() {
       ArrayList<Map.Entry<CharSequence, CharSequence>> list = new ArrayList<>(values.length);
+      addNamesAndValuesToList(list);
+      return Collections.unmodifiableList(list);
+    }
+
+    protected final void addNamesAndValuesToList(
+        List<Map.Entry<CharSequence, CharSequence>> list) {
       for (int i = 0; i < namesAndValuesIdx; i += 2) {
         String name = new String(namesAndValues[i], US_ASCII);
         // If binary headers, the value is base64 encoded.
         AsciiString value = values[i / 2];
         list.add(new AbstractMap.SimpleImmutableEntry<CharSequence, CharSequence>(name, value));
       }
-      return Collections.unmodifiableList(list);
     }
 
     protected final String namesAndValuesToString() {
@@ -494,6 +499,27 @@ public int size() {
       return size;
     }
 
+    @Override
+    public Iterator<Map.Entry<CharSequence, CharSequence>> iterator() {
+      List<Map.Entry<CharSequence, CharSequence>> list = new ArrayList<>(size());
+      addIfPresent(list, PATH_HEADER, path);
+      addIfPresent(list, AUTHORITY_HEADER, authority);
+      addIfPresent(list, METHOD_HEADER, method);
+      addIfPresent(list, SCHEME_HEADER, scheme);
+      addIfPresent(list, TE_HEADER, te);
+      addNamesAndValuesToList(list);
+      return Collections.unmodifiableList(list).iterator();
+    }
+
+    private static void addIfPresent(
+        List<Map.Entry<CharSequence, CharSequence>> list, AsciiString name, AsciiString value) {
+      if (value != null) {
+        list.add(
+            new AbstractMap.SimpleImmutableEntry<CharSequence, CharSequence>(
+                name.toString(), value));
+      }
+    }
+
     @Override
     public String toString() {
       StringBuilder builder = new StringBuilder(getClass().getSimpleName()).append('[');

netty/src/test/java/io/grpc/netty/GrpcHttp2HeadersUtilsTest.java

@@ -328,6 +328,42 @@ public void headerIteartor_nonEmpty() {
     assertThat(it.hasNext()).isFalse();
   }
 
+  @Test
+  public void headerIterator_withPseudoHeadersAndTe() {
+    Http2Headers http2Headers = new GrpcHttp2RequestHeaders(2);
+    http2Headers.add(AsciiString.of(":path"), AsciiString.of("mypath"));
+    http2Headers.add(AsciiString.of(":authority"), AsciiString.of("myauthority"));
+    http2Headers.add(AsciiString.of(":method"), AsciiString.of("mymethod"));
+    http2Headers.add(AsciiString.of(":scheme"), AsciiString.of("myscheme"));
+    http2Headers.add(AsciiString.of("te"), AsciiString.of("trailers"));
+    http2Headers.add(AsciiString.of("custom"), AsciiString.of("val"));
+    Iterator<Map.Entry<CharSequence, CharSequence>> it = http2Headers.iterator();
+
+    assertNextEntry(it, ":path", AsciiString.of("mypath"));
+    assertNextEntry(it, ":authority", AsciiString.of("myauthority"));
+    assertNextEntry(it, ":method", AsciiString.of("mymethod"));
+    assertNextEntry(it, ":scheme", AsciiString.of("myscheme"));
+    assertNextEntry(it, "te", AsciiString.of("trailers"));
+    assertNextEntry(it, "custom", AsciiString.of("val"));
+    assertThat(it.hasNext()).isFalse();
+  }
+
+  @Test
+  public void headerIterator_nullPseudoHeadersSkipped() {
+    Http2Headers http2Headers = new GrpcHttp2RequestHeaders(2);
+    http2Headers.add(AsciiString.of(":path"), AsciiString.of("mypath"));
+    http2Headers.add(AsciiString.of(":authority"), AsciiString.of("myauthority"));
+    http2Headers.remove(AsciiString.of(":authority"));
+    http2Headers.add(AsciiString.of(":scheme"), AsciiString.of("myscheme"));
+    http2Headers.add(AsciiString.of("custom"), AsciiString.of("val"));
+    Iterator<Map.Entry<CharSequence, CharSequence>> it = http2Headers.iterator();
+
+    assertNextEntry(it, ":path", AsciiString.of("mypath"));
+    assertNextEntry(it, ":scheme", AsciiString.of("myscheme"));
+    assertNextEntry(it, "custom", AsciiString.of("val"));
+    assertThat(it.hasNext()).isFalse();
+  }
+
   private static void assertNextEntry(
       Iterator<Map.Entry<CharSequence, CharSequence>> it, CharSequence key, CharSequence value) {
     Map.Entry<CharSequence, CharSequence> entry = it.next();

netty/src/test/java/io/grpc/netty/NettyServerHandlerTest.java

@@ -80,6 +80,7 @@
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPromise;
 import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http2.DefaultHttp2FrameWriter;
 import io.netty.handler.codec.http2.DefaultHttp2Headers;
 import io.netty.handler.codec.http2.Http2CodecUtil;
 import io.netty.handler.codec.http2.Http2Error;
@@ -764,6 +765,71 @@ public void headersWithOnlyHostBecomesAuthority() throws Exception {
     Truth.assertThat(metadataCaptor.getValue().get(hostKey)).isNull();
   }
 
+  @Test
+  public void trailersWithPseudoHeadersShouldFail() throws Exception {
+    manualSetUp();
+    createStream();
+
+    Http2Headers trailers = new DefaultHttp2Headers()
+        .method(HTTP_METHOD)
+        .set(CONTENT_TYPE_HEADER, CONTENT_TYPE_GRPC)
+        .set(TE_HEADER, TE_TRAILERS)
+        .path(new AsciiString("/smuggled/method"));
+    channelRead(trailersFrame(STREAM_ID, trailers));
+
+    verifyWrite()
+        .writeRstStream(
+            eq(ctx()),
+            eq(STREAM_ID),
+            eq(Http2Error.PROTOCOL_ERROR.code()),
+            any(ChannelPromise.class));
+    verify(transportListener, times(1))
+        .streamCreated(any(ServerStream.class), anyString(), any(Metadata.class));
+    ArgumentCaptor<Status> captor = ArgumentCaptor.forClass(Status.class);
+    verify(streamListener).closed(captor.capture());
+    assertEquals(Code.INTERNAL, captor.getValue().getCode());
+    verify(streamListener, never()).halfClosed();
+  }
+
+  @Test
+  public void trailersWithPseudoHeadersAfterRejectedHeadersShouldFail() throws Exception {
+    manualSetUp();
+    Http2Headers badHeaders = new DefaultHttp2Headers()
+        .method(HTTP_METHOD)
+        .path(new AsciiString("/foo/bar"));
+    channelRead(headersFrame(STREAM_ID, badHeaders));
+    verifyWrite()
+        .writeHeaders(
+            eq(ctx()),
+            eq(STREAM_ID),
+            any(Http2Headers.class),
+            eq(0),
+            eq(false),
+            any(ChannelPromise.class));
+
+    Http2Headers trailers = new DefaultHttp2Headers()
+        .method(HTTP_METHOD)
+        .set(CONTENT_TYPE_HEADER, CONTENT_TYPE_GRPC)
+        .set(TE_HEADER, TE_TRAILERS)
+        .path(new AsciiString("/smuggled/method"));
+    channelRead(trailersFrame(STREAM_ID, trailers));
+
+    verifyWrite()
+        .writeRstStream(
+            eq(ctx()),
+            eq(STREAM_ID),
+            eq(Http2Error.PROTOCOL_ERROR.code()),
+            any(ChannelPromise.class));
+    verify(transportListener, never())
+        .streamCreated(any(ServerStream.class), anyString(), any(Metadata.class));
+  }
+
+  private ByteBuf trailersFrame(int streamId, Http2Headers headers) {
+    ChannelHandlerContext ctx = newMockContext();
+    new DefaultHttp2FrameWriter().writeHeaders(ctx, streamId, headers, 0, true, newPromise());
+    return captureWrite(ctx);
+  }
+
   @Test
   public void keepAliveManagerOnDataReceived_headersRead() throws Exception {
     manualSetUp();