CODEWITHSUNDEEP
php
Nikk
Nikk

Reputation: 7921

php Mac Address check format

I am getting the mac of the user from the url. What I'm trying to do is match to see if the address is genuine. Cause I'll be running it against a database and I don't want to run it if it's not the right format.

This is what I have so far:

if (isset($_GET['mac'])) { 
    if (strlen($_GET['mac']) == 18) { 
        $get_mac_filtered = preg_replace('/^([a-fA-F0-9]{2}:){5}[a-fA-F0-9]{2}$/', '',$_GET['mac']);
            if (preg_match('/^([a-fA-F0-9]{2}:){5}[a-fA-F0-9]{2}$/', $_GET['mac']) == $get_mac_filtered) {
                echo 'Got a mac match! '.$get_mac_filtered;
            }else {
                echo 'Sorry !=';
            }
}else {die();} }

I'm guessing the problem is somewhere in here (preg_match('/^([a-fA-F0-9]{2}:){5}[a-fA-F0-9]{2}$/', $_GET['mac']) == $get_mac_filtered) because it returns else

Upvotes: 1

Views: 10845

Answers (2)

j0k
j0k

Reputation: 22756

Available since PHP 5.5, the best way to validate a MAC address is using filter_var with the constant FILTER_VALIDATE_MAC:

var_dump(filter_var('FA-F9-DD-B2-5E-0D', FILTER_VALIDATE_MAC));
// string(17) "FA-F9-DD-B2-5E-0D"

var_dump(filter_var('DC:BB:17:9A:CE:81', FILTER_VALIDATE_MAC));
// string(17) "DC:BB:17:9A:CE:81"

var_dump(filter_var('96-D5-9E-67-40-AB', FILTER_VALIDATE_MAC));
// string(17) "96-D5-9E-67-40-AB"

var_dump(filter_var('96-D5-9E-67-40', FILTER_VALIDATE_MAC));
// bool(false)

var_dump(filter_var('', FILTER_VALIDATE_MAC));
// bool(false)

So you can just do:

if (false === filter_var($_GET['mac'], FILTER_VALIDATE_MAC)) {
    throw new \Exception('Invalid mac address');
}

Upvotes: 8

user149341
user149341

Reputation:

Remove this line. It does nothing useful:

$get_mac_filtered = preg_replace('/^([a-fA-F0-9]{2}:){5}[a-fA-F0-9]{2}$/', '',$_GET['mac']);

As written, this replaces anything resembling a valid MAC address with… nothing. This is almost certainly not what you want to do here.

Instead, on the next line, compare the results of preg_match() to 1. (It returns 1 if the regular expression matches, and 0 if it does not.)

Upvotes: 0

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