What's the best (most secure) way of implementing session handling in a web server? I'd like to add that, but don't know how to implement it really. Is cookies a "must" for session handling? (To be able to identify which session)
The session handling isn't really your concern. It is handled by the HttpSession class (read the description in the javadoc!), which you can obtain by calling request.getSession().
It works in two ways (no need for you to do anything to support them):
using a session cookie (if cookies are allowed)
using url-rewriting - appending the session id (JSESSIONID) to the URL.
(Note: it is actually handled by the servlet container (Tomcat, jetty, etc) which provides an implementation of HttpSession)
Assuming that you're talking about a servlet container, then session handling comes backed in. See the relevant part of if the JavaEE tutorial. It covers the session API, as well as how sessions are tracked (cookie or URL rewriting).
Session handling is handled by the web container. If you want safety from prying eyes, use https (enforced in web.xml).
What you might be interested in also, is how the user identifies himself to the web container. Several options exist, where the most secure is the client uses a web browser with a digital certificate. That is quite tedious, but very secure :)
Related
actually I'm just starting to play around spring mvc in webapp and I have tumble across spring security which handles the authentication and session. My question is how does it handles session and can I create my own session id reference for spring security to use. I did use spring security but somewhat I feel blinded by it's process. Another thing is that can I add my own session service that I can control more if its implementable can you give me an insight in where can I start.. Furthermore I'm sorry for my English and if it is a duplicate question, though I think that topics concerning with spring security doesn't satisfy what i had in mind... Thanks for the feedback...
Spring Security handles sessions nicely on its own. If you make a request, it'll append the session id in the response. You can read it and store it if you want to, so you can send it back as a cookie. We use this method with our Android application, because it does not handle it automatically as web browsers do.
If you're making a web application, the browser will store and send back the session id, so you don't have to worry about it.
It seems that spring security implementation is not tied to HTTP session directly, take a look at this package org.springframework.security.core.session, There is SessionCreationEvent, SessionDestroyedEvent and SessionInformation. SessionInformation assumes that you have a String ID for the session but nothing else.
Now of you take a look at SessionRegistryImpl the java doc says you have to add org.springframework.security.web.session.HttpSessionEventPublisher to your web.xml for the registry to be notified of the session events. So if you want to provide your own implementation of session management just replace HttpSessionEventPublisher with your own implementation.
I'm implementing a game in JSP and Servlets. The game should support multiple players.
It is obvious that each player ID is generated on the server side. But where do I store it on the client side, so I can retrieve it later (from within the servlet) when the client calls for the Servlet?
Sessions are handled automatically by the servlet framework, and you retrieve the session by calling request.getSession() in a servlet.
The session is available in different ways once you start using a framework once you outgrow servlets (this happens quickly) and is framework-dependent.
Depends on how long you want the client to remember the player ID.
During the session: The session is a good place
During his subsequent visists: A (permanent) cookie is a good place
Session: request.getSession()
Cookie: request.getCookies() and response.addCookie(cookie)
Session ids are usually stored in a cookie.
I'd be amazed if JSP doesn't have a session library that would take care of all that for you.
I'm using gwt on my glassfish server, and I'm attempting to make some of my RPC calls authenticated via cookies. Is this possible? Are there any examples out there of how to code it?
Depending only on the cookie for authentication will make your website/services vulnerable to Cross-Site Request Forging/XSRF/CSRF attacks - read more on that in Security for GWT Applications.
The best way would be to double check the value you get from the cookie and with the one that's been transported to the server by some other means - as part of the request (header, a custom field, etc).
Other than that, there are many tutorials covering the subject - just search for Java (servlet) authentication - it doesn't have to be GWT-specific. The Google Web Toolkit Group also has many threads about the subject.
I assume that you use GWT's RPC servlet for handling requests made by the client.
One option that comes to my mind is to write and configure a ServletFilter which can examine the cookie, before the request reaches GWT's servlet.
You might rethink using cookies as it is a potencial security hole.
Why not put your communication to HTTPS?
Can you not just use the standard 'session' scope, i.e.
request.getSession()
A pattern I use in GWT apps is to have a separate 'old fashioned' login form which sets up the session. The GWT app's host page is then displayed after they have successfully logged in.
If the necessary values aren't in the session, then the user isn't logged in. Your service should return an exception, maybe, which instructs the GWT app to redirect to the login page, or display an error.
Best way managing session in Java. I heard that cookies are not reliable option for this as they gets stored into browser and can be accessed later on? Is this correct? If possible please come up with the answers with the coding example.
Which is the best among:
URL Rewriting: Server will add an additional parameter at the end of URL link
Hidden parameter in Form: server will add an additional parameter at every form in HTML
cookie: Server will ask browser to maintain a cookie.
The session management (client identification, cookie handling, saving session scoped data and so on) is basically already done by the appserver itself. You don't need to worry about it at all. You can just set/get Java objects in the session by HttpSession#setAttribute() and #getAttribute(). Only thing what you really need to take care of is the URL rewriting for the case that the client doesn't support cookies. It will then append a jsessionid identifier to the URL. In the JSP you can use the JSTL's c:url for this. In the Servlet you can use HttpServletResponse#encodeURL() for this. This way the server can identify the client by reading the new request URL.
Your new question shall probably be "But how are cookies related to this? How does the server do it all?". Well, the answer is this: if the server receives a request from a client and the server side code (your code) is trying to get the HttpSession by HttpServletRequest#getSession() while there's no one created yet (first request in a fresh session), the server will create a new one itself. The server will generate a long, unique and hard-to-guess ID (the one which you can get by HttpSession#getId()) and set this ID as a value of the cookie with the name jsessionid. Under the hood the server uses HttpServletResponse#addCookie() for this. Finally the server will store all sessions in some kind of Map with the session ID as key and the HttpSession as value.
According to the HTTP cookie spec the client is required to send the same cookies back in the headers of the subsequent request. Under the hood the server will search for the jsessionid cookie by HttpServletRequest#getCookies() and determine its value. This way the server is able to obtain the associated HttpSession and give it back by every call on HttpServletRequest#getSession().
To the point: the only thing which is stored in the client side is the session ID (in flavor of a cookie) and the HttpSession object (including all of its attributes) is stored in the server side (in Java's memory). You don't need to worry about session management youself and you also don't need to worry about the security.
See also:
Authenticating the username, password by using filters in Java (contacting with database)
How to redirect to Login page when Session is expired in Java web application?
How to implement "Stay Logged In" when user login in to the web application
All Java web frameworks support cookies or URL-encoded session IDs. They will chose the correct approach automatically, so there is nothing you need to do. Just request the session object from your container and it will handle the details.
[EDIT] There are two options: Cookies and a special URL. There are problems with both approaches. For example, if you encode the session in an URL, people can try to pass the session on (by putting the URL into a mail, for example). If you want to understand this, read a couple of articles about security and build app servers. Otherwise: Your Java app server will do the right thing for you. Don't think about it.
The cookie just stores the session ID, this ID is useless once the session has expired.
Servlet specification defines the API for accessing/setting session data in standard J2EE application. Also it defines that session data is stored on the server-side and nothing is transferred to the client except the session identifier. There are 2 mechanisms how session id is transferred:
1) request URL e.g. jessionid=....
2) cookie
Mechanism is determined automatically based on client capabilities.
EDIT. There is no best option, there is servlet specification that defines the way.
Http is a stateless, client-side pull only protocol.
To implement a stateful conversation over it, Java EE Web Server need to hide some information (which is sessionid) in client-side and the mechanism it can use should follow HTTP and HTML spec.
There are three ways to accomplish this goal:
URL Rewriting: Server will add an additional parameter at the end of URL link.
Hidden parameter in Form: server will add an additional parameter at every form in HTML.
cookie: Server will ask browser to maintain a cookie.
Basically, modern web server will have a "filter" to choose which way to use automatically.
So if Server detected that browser already turn off cookie support, it will switch to other ways.
2 important questions:
Which web technology are you using? JSF, Struts, SpringMVC or just plain servlets/JSPs.
Servlets/JSPs already give you the session support you need. JSP Example: Hello, <%= session.getAttribute( "theName" ) %>
I really don't think you have something to worry about cookies, since the data is stored safely in the server and handeling the cookie is done automaticlly.
Is your application installed on a single server?
If YES than you have no problem, use the servlet session option.
if NO than you gotta find another way to do this. Like using a sticky session, or maybe parse the entire session object in the requests/responses as a field. This option indeed requires you to take security measures.
I'm working on an existing j2ee app and am required to remove some vendor specific method calls from the code.
The daos behind a session facade make calls into the ejb container to get the user's id and password - in order to connect to the database. The user id and password part of the initialContext used to connect to the server.
I am able to get the userid using sessionContext.getCallerPrincipal()
Is there anyway to get to the SECURITY_CREDENTIALS used on the server connection or, is there a way to pass information from the server connection into the ejbs (they are all stateless session beans).
This is a large app with both a rich-client and web front end, and in a perfect world I'd be happy to go back and re-architect the entire solution to use J2EE security etc - but unfortunately, that is not realistic.
I can't give you a generic solution, but this is what has worked for us. We have the app server connect to LDAP as a specific user that has the ability to request credentials for other users. Then we have some generic security code that we can use to request a users credentials from inside the session beans, based on the users identity from their initial login (just as you are doing it via getCallerPrincipal()).
We also place the users identity in a thread local variable, so that classes down the call chain from the EJB do not have to be "container aware". They simply access the identity from the thread local and use the security classes to look up user profile information. This also makes it easy to change the implementation for testing, or even something other than LDAP lookups.
Other conveniences we created were a JDBCServiceLocator that retrieves connections with user/password for the current user. So the developer does not have to explicitly code the security lookups at all.
Normally the Java EE security model will not allow the retrieval of the user password, for security reasons. But it depends on the implementation. Some vendors provide methods to retrieve this kind of information, but if you rely on such implementations, be aware that the portability of the application will be compromised.
One common approach is to write a servlet filter to intercept the login request and save a copy of the credentials, to be used later. If your application doesn't use the Java EE security infrastructure, this could be easily implemented. That's because some vendors prevent you from filtering an authentication servlet.
Robin,
Sounds like what I was planning. I figured I'd make a call right after a successful server connection to load the credentials into a threadLocal variable on my connection class. I was hoping there was an easier way - but I guess not.