From d35c8f881e08d9cd02a3842828313e8854228d29 Mon Sep 17 00:00:00 2001
From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Sun, 29 Dec 2024 16:49:50 +0900
Subject: [PATCH] Explicitly deny new server-initiated bidirectional stream

Vanilla HTTP/3 does not allow server to create bidirectional stream.
libnghttp3 expects that application configures the QUIC stack like so.
Still it would be nice to explicitly deny new server-initiated
bidirectional stream for clarity.
---
 lib/nghttp3_conn.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/nghttp3_conn.c b/lib/nghttp3_conn.c
index 1f6c857..0f04e94 100644
--- a/lib/nghttp3_conn.c
+++ b/lib/nghttp3_conn.c
@@ -434,6 +434,10 @@ nghttp3_ssize nghttp3_conn_read_stream(nghttp3_conn *conn, int64_t stream_id,
             return rv;
           }
         }
+      } else if(!nghttp3_stream_uni(stream_id)) {
+        /* server does not expect to receive new server initiated
+           bidirectional stream from client. */
+        return NGHTTP3_ERR_H3_STREAM_CREATION_ERROR;
       } else {
         /* unidirectional stream */
         if (srclen == 0 && fin) {