From 5bd75183438cbc2e61575dd6e3344f2ec542cf4d Mon Sep 17 00:00:00 2001
From: Erik Ekman <erik@kryo.se>
Date: Fri, 22 Jan 2021 20:19:44 +0100
Subject: [PATCH] netdb: Accept '0' as service in lwip_getaddrinfo

Fixes bug #59925
---
 src/api/netdb.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/api/netdb.c b/src/api/netdb.c
index b6891de7..ee782978 100644
--- a/src/api/netdb.c
+++ b/src/api/netdb.c
@@ -305,7 +305,11 @@ lwip_getaddrinfo(const char *nodename, const char *servname,
     /* service name specified: convert to port number
      * @todo?: currently, only ASCII integers (port numbers) are supported (AI_NUMERICSERV)! */
     port_nr = atoi(servname);
-    if ((port_nr <= 0) || (port_nr > 0xffff)) {
+    if (port_nr == 0 && (servname[0] != '0')) {
+      /* atoi failed - service was not numeric */
+      return EAI_SERVICE;
+    }
+    if ((port_nr < 0) || (port_nr > 0xffff)) {
       return EAI_SERVICE;
     }
   }