I’ve come across an issue where a web application has managed to create a cookie on the client, which, when submitted by the client to Apache, causes Apache to return the following:
HTTP/1.1 400 Bad Request
Date: Mon, 08 Mar 2010 21:21:21 GMT
Server: Apache/2.2.3 (Red Hat)
Content-Length: 7274
Connection: close
Content-Type: text/html; charset=iso-8859-1
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>400 Bad Request</title>
</head><body>
<h1>Bad Request</h1>
<p>Your browser sent a request that this server could not understand.<br />
Size of a request header field exceeds server limit.<br />
<pre>
Cookie: ::: A REALLY LONG COOKIE ::: </pre>
</p>
<hr>
<address>Apache/2.2.3 (Red Hat) Server at www.foobar.com Port 80</address>
</body></html>
After looking into the issue, it would appear that the web application has managed to create a really long cookie, over 7000 characters. Now, don’t ask me how the web application was able to do this, I was under the impression browsers were supposed to prevent this from happening. I’ve managed to come up with a solution to prevent the cookies from growing out of control again.
The issue I’m trying to tackle is how do I reset the large cookie on the client if every time the client tries to submit a request to Apache, Apache returns a 400 client error? I’ve tried using the ErrorDocument directive, but it appears that Apache bails on the request before reaching any custom error handling.
Oh dear! I think you’ll have to at increase the LimitRequestFieldSize configuration option in Apache’s
httpd.confto go any further, so you can get as far as running the server-side script. Make sure it cleans up the cookies as quickly as possible before they start to grow again!