From 8518d08ff3c5864c8d8009f949ee5b1e716f8ddb Mon Sep 17 00:00:00 2001
From: Till Zimmermann <tzimmermann@uni-osnabrueck.de>
Date: Thu, 9 May 2019 13:08:19 +0200
Subject: [PATCH] Fixed Segmentation Fault / NULLptr dereference

Signed-off-by: Till Zimmermann <tzimmermann@uni-osnabrueck.de>
---
 client/client_shared.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/client/client_shared.c b/client/client_shared.c
index 8569651d..b1cbd7bb 100644
--- a/client/client_shared.c
+++ b/client/client_shared.c
@@ -662,6 +662,10 @@ int client_config_line_proc(struct mosq_config *cfg, int pub_or_sub, int argc, c
 					return 1;
 				}
 				topic = strchr(url, '/');
+				if(!topic){
+					fprintf(stderr, "Error: invalid URL for -L argument specified.\n\n");
+					return 1;
+				}
 				*topic++ = 0;
 
 				if(cfg_add_topic(cfg, pub_or_sub, topic, "-L topic"))