From 98080c7d07cbc1110f1495fee0613f3815a92218 Mon Sep 17 00:00:00 2001
From: Aaron Riedel <git@ar21.de>
Date: Wed, 24 Jul 2024 14:06:03 +0200
Subject: [PATCH] add validity check for ipv4 addresses

---
 ddns4.sh | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ddns4.sh b/ddns4.sh
index ab2e6fb..7388416 100755
--- a/ddns4.sh
+++ b/ddns4.sh
@@ -44,10 +44,10 @@ echo -e "${INFO} started $(date)"
 echo -e "${INFO} DNS Record will be $SUBDOMAIN_IPV4.$DNSZONE_IPV4"
 echo -e "${PENDING} get IP address"
 IPv4="$(curl -s4 https://ip.hetzner.com)"
-if [[ -z $IPv4 ]]; then
+if [[ -z $IPv4 || ! $IPv4 =~ ^[0-9]{1,3}("."[0-9]{1,3}){3}$ ]]; then
 	IPv4="$(curl -s4 https://icanhazip.com)"
-fi	
-if [[ -z $IPv4 ]]; then
+fi
+if [[ -z $IPv4 || ! $IPv4 =~ ^[0-9]{1,3}("."[0-9]{1,3}){3}$ ]]; then
 	echo -e "${REPLACE}${FAIL} IPv4 not found"
 	exit 1
 else