From 65c7d9cc88079e57667846852ce338d8d29de27d Mon Sep 17 00:00:00 2001
From: Marco Ochse <t3chn0m4g3@users.noreply.github.com>
Date: Thu, 28 Sep 2017 13:30:39 +0200
Subject: [PATCH] check valid ipv4

---
 bin/myip.sh | 131 +++++++++++++++++++++++++++++-----------------------
 1 file changed, 73 insertions(+), 58 deletions(-)

diff --git a/bin/myip.sh b/bin/myip.sh
index 86a9114e..e464b421 100755
--- a/bin/myip.sh
+++ b/bin/myip.sh
@@ -6,83 +6,98 @@ timeout=2   # seconds to wait for a reply before trying next server
 verbose=1   # prints which server was used to STDERR
 
 dnslist=(
-    "dig +short            myip.opendns.com        @resolver1.opendns.com"
-    "dig +short            myip.opendns.com        @resolver2.opendns.com"
-    "dig +short            myip.opendns.com        @resolver3.opendns.com"
-    "dig +short            myip.opendns.com        @resolver4.opendns.com"
-    "dig +short -4 -t a    whoami.akamai.net       @ns1-1.akamaitech.net"
-    "dig +short            whoami.akamai.net       @ns1-1.akamaitech.net"
+  "dig +short            myip.opendns.com        @resolver1.opendns.com"
+  "dig +short            myip.opendns.com        @resolver2.opendns.com"
+  "dig +short            myip.opendns.com        @resolver3.opendns.com"
+  "dig +short            myip.opendns.com        @resolver4.opendns.com"
+  "dig +short -4 -t a    whoami.akamai.net       @ns1-1.akamaitech.net"
+  "dig +short            whoami.akamai.net       @ns1-1.akamaitech.net"
 )
 
 httplist=(
-    alma.ch/myip.cgi
-    api.infoip.io/ip
-    api.ipify.org
-    bot.whatismyipaddress.com
-    canhazip.com
-    checkip.amazonaws.com
-    eth0.me
-    icanhazip.com
-    ident.me
-    ipecho.net/plain
-    ipinfo.io/ip
-    ipof.in/txt
-    ip.tyk.nu
-    l2.io/ip
-    smart-ip.net/myip
-    wgetip.com
-    whatismyip.akamai.com
+  alma.ch/myip.cgi
+  api.infoip.io/ip
+  api.ipify.org
+  bot.whatismyipaddress.com
+  canhazip.com
+  checkip.amazonaws.com
+  eth0.me
+  icanhazip.com
+  ident.me
+  ipecho.net/plain
+  ipinfo.io/ip
+  ipof.in/txt
+  ip.tyk.nu
+  l2.io/ip
+  smart-ip.net/myip
+  wgetip.com
+  whatismyip.akamai.com
 )
 
+# function to check for valid ip
+function valid_ip()
+{
+  local  ip=$1
+  local  stat=1
+
+  if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
+    OIFS=$IFS
+    IFS='.'
+    ip=($ip)
+    IFS=$OIFS
+    [[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \
+        && ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]
+    stat=$?
+  fi
+  return $stat
+}
+
 # function to shuffle the global array "array"
 shuffle() {
-   local i tmp size max rand
-   size=${#array[*]}
-   max=$(( 32768 / size * size ))
-   for ((i=size-1; i>0; i--)); do
-      while (( (rand=$RANDOM) >= max )); do :; done
-      rand=$(( rand % (i+1) ))
-      tmp=${array[i]} array[i]=${array[rand]} array[rand]=$tmp
-   done
+  local i tmp size max rand
+  size=${#array[*]}
+  max=$(( 32768 / size * size ))
+  for ((i=size-1; i>0; i--)); do
+    while (( (rand=$RANDOM) >= max )); do :; done
+    rand=$(( rand % (i+1) ))
+    tmp=${array[i]} array[i]=${array[rand]} array[rand]=$tmp
+  done
 }
-
 # if we have dig and a list of dns methods, try that first
 if hash dig 2>/dev/null && [ ${#dnslist[*]} -gt 0 ]; then
-    eval array=( \"\${dnslist[@]}\" )
-    shuffle
-
-    for cmd in "${array[@]}"; do
-        [ "$verbose" == 1 ] && echo Trying: $cmd 1>&2
-        ip=$(timeout $timeout $cmd)
-        if [ -n "$ip" ]; then
-            echo $ip
-            exit
-        fi
-    done
+  eval array=( \"\${dnslist[@]}\" )
+  shuffle
+  for cmd in "${array[@]}"; do
+    [ "$verbose" == 1 ] && echo Trying: $cmd 1>&2
+    ip=$(timeout $timeout $cmd)
+    if [ -n "$ip" ]; then
+      if valid_ip $ip; then
+        echo $ip 
+        exit
+      fi
+    fi
+  done
 fi
-
 # if we haven't succeeded with DNS, try HTTP
 if [ ${#httplist[*]} == 0 ]; then
-    echo "No hosts in httplist array!" >&2
-    exit 1
+  echo "No hosts in httplist array!" >&2
+  exit 1
 fi
-
 # use curl or wget, depending on which one we find
-curl_or_wget=$(if hash curl 2>/dev/null; then echo curl; elif hash wget 2>/dev/null; then echo "wget -qO-"; fi);
-
+curl_or_wget=$(if hash curl 2>/dev/null; then echo "curl -s"; elif hash wget 2>/dev/null; then echo "wget -qO-"; fi);
 if [ -z "$curl_or_wget" ]; then
-    echo "Neither curl nor wget found. Cannot use http method." >&2
-    exit 1
+  echo "Neither curl nor wget found. Cannot use http method." >&2
+  exit 1
 fi
-
 eval array=( \"\${httplist[@]}\" )
 shuffle
-
 for url in "${array[@]}"; do
-    [ "$verbose" == 1 ] && echo Trying: $curl_or_wget -s "$url" 1>&2
-    ip=$(timeout $timeout $curl_or_wget -s "$url")
-    if [ -n "$ip" ]; then
-        echo $ip
-        exit
+  [ "$verbose" == 1 ] && echo Trying: $curl_or_wget "$url" 1>&2
+  ip=$(timeout $timeout $curl_or_wget "$url")
+  if [ -n "$ip" ]; then
+    if valid_ip $ip; then 
+      echo $ip 
+      exit
     fi
+  fi
 done