Stored cookie dissapearing after captive portal authentication

Question

Obligatory "I'm new at this".

I'm having an issue where a cookie doesn't seem to be persisting after captive portal login. I have a captive portal set up where it lands on our web server, stores mac and a unique ID on 2 cookies, redirects them elsewhere for authentication, and then they come back to our webserver where we look up that uid and return a unique code. Testing this on a windows computer it works fine, however on an android phone it doesn't. It seems that on an android phone I can see that the cookie is set, on that default browser you get with wifi hotspots, because I have made that page echo the value. But then when I manually enter in the url in the chrome browser it shows me that the cookie is no longer set to any value. Tested this on 2 android phones and my windows laptop (which again works fine). Any ideas on this?

This probably looks like a shambles.

This is the first page they land on:

$sql = "select uid from table where mac =('$client_mac_address')";
$uidResult = $conn->query($sql);
if($uidResult->num_rows > 0) {
    while($row = mysqli_fetch_array($uidResult)) {
        $cookie_uid = "UID";
        echo $row['uid'];
        setcookie($cookie_uid,$row['uid'],time() + (86400 * 30),"/");
        if(!isset($_COOKIE[$cookie_uid])) {
            echo "Cookie named '" . $cookie_uid . "' is not set!";
        } else {
            echo "Cookie '" . $cookie_uid . "' is set!<br>";
            echo "Value is: " . $_COOKIE[$cookie_uid];
            echo $_COOKIE[$cookiename];
        }
    }
};

This is the final page they land on I'm getting their MAC first and then using it to find the uid later:

<?php

$cookiename = "UID";
if(!isset($_COOKIE[$cookiename])) {
    echo "Cookie '" . $cookiename . "' isn't set <br>";
} else {
    echo "Cookie '" . $cookiename . "' is set <br>";
    echo "Value: " . $_COOKIE[$cookiename];
}

?>

<script>
function getCookie(UID) {
  var name = UID + "=";
  var decodedCookie = decodeURIComponent(document.cookie);
  var ca = decodedCookie.split(';');
  for(var i = 0; i <ca.length; i++) {
    var c = ca[i];
    while (c.charAt(0) == ' ') {
      c = c.substring(1);
    }
    if (c.indexOf(name) == 0) {
      return c.substring(name.length, c.length);
    }
  }
  return "";
}

function getCode(){
    var uid = getCookie("UID");
    if (uid == "") {
        return;
        console.log("empty");
    } else {
        if (window.XMLHttpRequest) {
            // code for IE7+, Firefox, Chrome, Opera, Safari
            xmlhttp = new XMLHttpRequest();
    } else {
        // code for IE6, IE5
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    xmlhttp.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {
            document.getElementById("divCode").innerHTML = this.responseText;
            console.log("on ready");
        }
    };
    xmlhttp.open("GET","getCode.php?q="+uid,true);
    console.log("open");
    xmlhttp.send();
    console.log("send");
    }           
}

</script>

which goes to a php file on the server to handle the get request:

$q = intval($_GET['q']);
echo "$q";
$servername = "localhost";
$username = "user";
$password = "password";
$dbname = "dbname";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
if (!$conn) {
    die('can't connect: ' . mysqli_error($conn));
}
mysqli_select_db($conn,"table");
$sql="SELECT code FROM table WHERE uid = ".$q;
$result = mysqli_query($conn,$sql);

echo "<table>
<tr>
<th>Code</th>
</tr>";
while($row = mysqli_fetch_array($result)) {
    echo "<tr>";
    echo "<td>" . $row['code'] . "</td>";
    echo "</tr>";
}
echo "</table>";
mysqli_close($conn);

Answer 1

Captive Portal stores the cookies in a sandbox environment, it doesn't share with the normal browser in android as well as ios.