Tuesday, 14 March 2017

cookie monster user agent compatibility mode and more–Load Balancer problems.

I’ve having issues with some cookies, specifically JSESSIONID.  Specifically when using ie11 and also specifically when I used a proxy server.  Yes – the combination of all of these are causing me to have immediate “your session has expired” messages from JDE.  This is a classic “load balancer not using JSESSIONID to manage web server affinity.  We’ve all seen it 20 times before.

  • The problem is that chrome works with the proxy
  • The problem is that ie11 works without the proxy.

So where is my problem?

Let’s start with some basics.

The JDE login page needs to make 295 calls back and forth.  This sends 172KB of traffic and receives 3.97MB.  Did you know that?  Cool stat!

The web server set’s a cookie almost immediately:

Key    Value
Set-Cookie    JSESSIONID=SoLLe2MGnfzecDkSIxm56qv8pf2a0SXrmjeRTFPGw84Xo8k89XBK!1342963082; path=/; HttpOnly

This expires at the end of the session.  Easy!

image

Note that this is used for all of the exchanges of gif’s and css’s.

Now, we try and login.

image

The first time we do a MAF call, we have the cookie set on us to a different value

URL    Protocol    Method    Result    Type    Received    Taken    Initiator    Wait‎‎    Start‎‎    Request‎‎    Response‎‎    Cache read‎‎    Gap‎‎
/jde/ResourceCanonicalsJS.mafService?e1UserActInfo=false&e1.mode=view&e1.namespace=&RENDER_MAFLET=E1Menu&e1.state=maximized&e1.service=ResourceCanonicalsJS    HTTP    GET    200    application/x-javascript    67.28 KB    78 ms    <script>    1404    0    31    47    0    234

We send:

Key    Value
Cookie    _ga=GA1.1.1246774349.1489119748; _gat=1; JSESSIONID=u1jLgQJ7eBiRq9_cBQ3KPSUN71R2OmOJtgWRcpySaAWKc6gxlJrU!1830213081; e1AppState=

but, the server sends us:

Key    Value
Set-Cookie    JSESSIONID=eTnLgQfKjk4NyAAkLYm8XvOij6Oax5WNqwM0zgPaYhe78J5j_Rt1!1342963082; path=/; HttpOnly

So the browser can only use the new value in the next request (but we’ve flunked our session, as the cookie originally passed was invalid)

The interesting thing is, that when I remove the proxy, the JSESSIONID is being sent all of the time!  Every request for a gif or png has the cookie in the request header.  So the proxy or browser is ripping this out very early!

The reply from the server is pretty simple – I do not know you here is a new JSESSIONID if you want to try again.

{"notificationReply": {"idle":0, "timedout":true, "logoutURL":"/jde/MafletClose.mafService?action=close&e1UserActInfo=false&e1.mode=view&jdemafjasFrom=SessionTimeout&e1.namespace=&RENDER_MAFLET=E1Menu&e1.state=maximized&e1.service=MafletClose"}}

See that we have an appstate and now 2 session ID’s!

Direction    Key    Value    Expires    Domain    Path    Secure    HTTP only
Sent    JSESSIONID    fwPLmXbOOv9FTQ1mY3cm_BFUAg3C5UuAfWmzDpK4T2as7ovnsVe4!1830213081                   
Sent    e1AppState    E1MENUMAIN_5531488967363928064:E1MENUMAIN_5531488967363928064|                   
Received    JSESSIONID    tgHLmXbO-vkMOxZmJr-1vfxgdeg7eJaq5JLxuYqLz5ljXrnUeEjn!1342963082    At end of session        /    No    Yes

The client is doing a post of the following content

    • Request headers:
    • Key  Value
    • Request    POST /jde/NotificationController.mafService HTTP/1.1
    • Accept     */*
    • Referer     http://jde92.xxxxx/jde/js/notificationWorker.js
    • Accept-Language en-AU
    • Content-Type    text/plain;charset=UTF-8
    • Accept-Encoding gzip, deflate
    • User-Agent Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko
    • Host jde92.xxxxx
    • Content-Length  5
    • Connection Keep-Alive
    • Cache-Control   no-cache
    • Cookie     _ga=GA1.1.1246774349.1489119748; JSESSIONID=FOLMOkDx9cu0Trx4oC7Joy24sGBo8pc-bdFde-mCP5vcDdCVrLY4!1342963082; _gat=1; e1AppState=E1MENUMAIN_3349205142792595456:E1MENUMAIN_3349205142792595456|
    • Sent payload
    • cmd=0
    • cmd=0

The response from this request is the Set-cookie

Key    Value
Response    HTTP/1.1 200 OK
Date    Tue, 14 Mar 2017 07:32:29 GMT
Content-Type    text/html; charset=UTF-8
Set-Cookie    JSESSIONID=YVbLu4qUOF1x4Fesurjkq-Fb-N54fgjN-sE0biUYng3md9cVHl5H!1830213081; path=/; HttpOnly
Content-Length    208

When chrome sends this – there is no reply with an alternate cookie in the header.

Wow, this is tough..  When you only have the client end of the comms – this is difficult to solve.

We got a LB consultant in who was able to hone in on LB side of things, and indeed was able to solve the problem. This is a complicated LB which actually detects the user agent and sends people to the appropriate JVM (because of activeX – if you know much about JDE you’ll understand this).   This is a nice fix and some cool functionality to put into the LB.

The browser was sending Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko which is wrong.

What was happening was that the rules around IE vs. other browsers were being triggered by certain payloads (so the browser emulation went generic for some posts), which then went to a different LB member and everything broke.  Wow!

What the consultant found was that JDE implemented this on some of their pages.

<meta http-equiv="X-UA-Compatible" content="IE=edge">

This client has “display intranet sites in compatibility mode”.  Which meant that JDE was being displayed in compatibility mode. What this does is it overrides the "Compatibility View" settings on IE and forces the it to use IE11 (as opposed to IE7 which is the "Compatibility View" default). This explains why I was seeing the IE11 user agent on some requests, and the IE7 user agent on others.

Note that this causes the browser to disregard the payload and request it again using the compatibility settings.  This means that accessing JDE in IE11 using compatibility mode and a fancy LB is going to break things every time.  You need to be careful what headers you are going to use when directing traffic.

You can fix this with the LB rules and search for some different options, not just IE11 – search for the agnet rv:11 for example.

Lessons, shift ctrl I in chrome is awesome, F12 in iexplore is awesome.  Browsers, proxies, compatibility mode and LB’s are complex beasts.

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