From 258cab1b22327a31016fe9db92a98b2843f1c5a6 Mon Sep 17 00:00:00 2001
From: Simon Goldschmidt <goldsimon@gmx.de>
Date: Mon, 23 Jul 2018 21:47:33 +0200
Subject: [PATCH] fix bug #54315 (IPV6_V6ONLY socket accepts IPV4 connections)

Signed-off-by: Simon Goldschmidt <goldsimon@gmx.de>
---
 src/core/tcp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/core/tcp.c b/src/core/tcp.c
index c98c43f5..dcf2495c 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -734,7 +734,11 @@ tcp_bind(struct tcp_pcb *pcb, const ip_addr_t *ipaddr, u16_t port)
     }
   }
 
-  if (!ip_addr_isany(ipaddr)) {
+  if (!ip_addr_isany(ipaddr)
+#if LWIP_IPV4 && LWIP_IPV6
+      || (IP_GET_TYPE(ipaddr) != IP_GET_TYPE(&pcb->local_ip))
+#endif /* LWIP_IPV4 && LWIP_IPV6 */
+     ) {
     ip_addr_set(&pcb->local_ip, ipaddr);
   }
   pcb->local_port = port;