From b934c3f4711fca0171e6a7d62c1f47b3d2ffd839 Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon@gmx.de>
Date: Mon, 28 Nov 2016 15:50:59 +0100
Subject: [PATCH] fixed bug #49726: setsockopt() set TCP_NODELAY TCP_KEEPALIVE
 ... with a listen state TCP will crash

---
 src/api/sockets.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/api/sockets.c b/src/api/sockets.c
index 4d2dd656..e493ba6b 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -2074,6 +2074,9 @@ lwip_getsockopt_impl(int s, int level, int optname, void *optval, socklen_t *opt
   case IPPROTO_TCP:
     /* Special case: all IPPROTO_TCP option take an int */
     LWIP_SOCKOPT_CHECK_OPTLEN_CONN_PCB_TYPE(sock, *optlen, int, NETCONN_TCP);
+    if (sock->conn->pcb.tcp->state == LISTEN) {
+      return EINVAL;
+    }
     switch (optname) {
     case TCP_NODELAY:
       *(int*)optval = tcp_nagle_disabled(sock->conn->pcb.tcp);
@@ -2467,6 +2470,9 @@ lwip_setsockopt_impl(int s, int level, int optname, const void *optval, socklen_
   case IPPROTO_TCP:
     /* Special case: all IPPROTO_TCP option take an int */
     LWIP_SOCKOPT_CHECK_OPTLEN_CONN_PCB_TYPE(sock, optlen, int, NETCONN_TCP);
+    if (sock->conn->pcb.tcp->state == LISTEN) {
+      return EINVAL;
+    }
     switch (optname) {
     case TCP_NODELAY:
       if (*(const int*)optval) {