Re: Cause of undefined offset notice

Most probably an IP-address with only 2 dots. $ php -r 'list($a, $b, $c, $d) = explode(".", "127.0.0");' PHP Notice: Undefined offset: 3 in Command line code on line 1 Martijn van Duren On 11/17/17 21:42, Jennifer wrote: > Hello, > > I have a script that compares a visitors IP address against a file of known bad addresses but > I'm getting this notice: > > Notice: Undefined offset: 3 (line 26 below) > > Can anyone see what I've done wrong? Perhaps this sub was not written correctly to begin > with? > > Thank you, > Jenni > > ----------------------------------------------------------- > > function validate_ip($ip_array, $cm) { > $msg = ''; > if (isset($cm['bad_ip_message'])) { > $msg = $cm['bad_ip_message']; > } > if (@strpos( $cm['remote_ip'], ':' ) !== false) { return false; } // Skip > IPv6 addresses (?). > > if (!is_array($ip_array)) { return false; } > foreach ($ip_array as $banned_ip) { > $banned_ip = trim($banned_ip); > if ($banned_ip[0] === '#' || $banned_ip === '') { continue; } // Skip > comments and blank lines. > > if ( @strpos( $banned_ip, '/' ) === false ) { > if (ip2long($banned_ip) === ip2long($cm['remote_ip'])) { > ban_message($msg); > } > if (substr($banned_ip, -1) == '0') { > $banned_ip .= '/24'; // Create a CIDR if IP ends in '0'. > } > } > if ( @strpos( $banned_ip, '/' ) !== false ) { > // Get the base and the bits from the CIDR. > list($base, $bits) = explode('/', $banned_ip); > > // Now split it up into it's classes. > list($a, $b, $c, $d) = explode('.', $base); // Notice: Undefined offset: 3 > > // Now do some bit shifting/switching to convert to ints. > $i = ($a << 24) + ($b << 16) + ($c << 8) + $d; > $mask = $bits == 0 ? 0: (~0 << (32 - $bits)); > > // Here's our lowest int. > $low = $i & $mask; > > // Here's our highest int. > $high = $i | (~$mask & 0xFFFFFFFF); > > // Now split up the IP we're checking against into classes. > list($a, $b, $c, $d) = explode('.', $cm['remote_ip']); > > // Now convert the IP we're checking against to an int. > $check = ($a << 24) + ($b << 16) + ($c << 8) + $d; > > // If the IP is within the range, including highest/lowest values, > // then it's within the CIDR range. > if ($check >= $low && $check <= $high) { > ban_message($msg); > } > } > } > return; > } >