Best Way To Bounce Users Without Getting XSSed

[neoform]

I have a login script that needs to be able to send the user back to where they were before logging in..

 

right now I'm using

login.php?b=previous_page.php

but this leaves me open for abuse from malicious links..  what would be the best way to protect from this sort of thing? I thought about cookies, but i'm not sure how i'd pull that off since i'd have to set a 'referral' cookie on virtually every page for it to know where to go back..

[rcorlew]

I don't know if this is the best way, here is what I am using at the moment to stop most of it,

 

<?php
$num_m = preg_match("[href|</A>|</a>|<]",  $_SERVER['QUERY_STRING'], $z1, PREG_OFFSET_CAPTURE);
if($num_m >= 1){
exit();
}
?>
//Rest of page in new <?php ?> brackets

 

I will keep adding stuff to the match as it besomes clear, but I think that should catch most of it.

[hitman6003]

echo $_SERVER['HTTP_REFERER'];

[Waldir]

header("Location: ".$_SERVER['HTTP_REFERER']);

[neoform]

header("Location: ".$_SERVER['HTTP_REFERER']);

 

that wont work if the page they're coming from is an action or something.. or if you actually want them to bounce to a different page.. :S

 

like to track outgoing clicks or something.. (just generalizing, but i'm looking for the most versatile method)

[Waldir]

specify which page u want to send them to:

 

header("Location: login.php");

 

works just as fine

[neoform]

i think i'mma use this:

 

function make_bounce($url = '')
{
if (isset($_SERVER['HTTP_REFERER']) && ! $url) 
	$url = $_SERVER['HTTP_REFERER'];
make_cookie('bounce', rawurlencode($url));
}

function bounce_user()
{
$url = isset($_COOKIE['bounce']) ? rawurldecode($_COOKIE['bounce']) : '';
kill_cookie('bounce');
if ($url)
	header('Location: '.$url);
}

unless someone sees a problem with this sorta method..