Spring Access Control - java

I working on Spring MVC app. The app funcionality is accessible through ReST API which jsp containing ajax logic consume. I am using spring security with defined roles (USER, COMPANY, ADMIN). Methods use requestMapping with responseBody such as:
www.app.com/auth/{userId}/request/{requestId}
It, of course, support GET for obtaining resource and POST for its creating or updating.
The problem is that after succesful login with, for example, userId = 1 I want GET request with requestId = 99. But when I run WebDev client for Chrome, I can also access another resource with easy request in format
www.app.com/auth/5/request/{requestId}
So basically, I can access resources, which I am not allowed to see. I hope you got the idea, where I am heading.
My question is - What is the best approach to secure this?
I was thinking about storing logged user Id (Integer) in session and comparing it everytime request for resource is made, but it seems to me that I am pulling the wrong end of rope :)
Thank you for any advice

You should have a look into the Expression-Based Access Control section of the spring security documentation.
Example copied from the documentation:
#PreAuthorize("#contact.name == authentication.name")
public void doSomething(Contact contact) {
..
}
This would check if name of the contact is equal to the name of the currently logged in user.
Using this this feature you can build much more sophisticated access rules than you could do with simple roles. However, this does not exclude using roles. You can still keep roles for basic security checks.

Related

Spring Boot - make sure data belongs to current logged in user

I have a Spring Boot REST API that I'm building. Im slightly stuck on the correct way to design my API in a way that protects each individual users' data. For example, consider the following database relations:
User -> (Has Many) Projects -> (Has Many) Tasks. (A User has-many Projects, and a Project has-many tasks).
For example, if I design my endpoints in the following way:
GET /api/v1/projects/{projectId}
POST /api/v1/projects/{projectId}/tasks
Just as a simple example for the above, how can I make sure, when creating new tasks for a certain project, that the project belongs to the logged in user?
Currently, I am using JWT tokens via Spring Security as my authentication strategy, and included in the payload of the token I have my Users' id. So with every request I can retrieve the user, but surely that's incredibly inefficient to be making so many requests to the database and check if the user actually has a given project.
Some solution I was thinking about is to simply have endpoints designed like this:
/api/v1/users/{userId}/projects/{projectId}/tasks
And then I can use the user id in the JWT payload and compare it to the user id in the request parameter. But then that would mean with every new relation in my database, the length of the url is going to be massive :) Also I guess it would mean all the business logic would be inside the User service for the whole application, right? Which seems a little odd to me... but maybe I'm wrong.
Im not sure if thats an issue or not, but just trying to design the API to be as elegant as possible.
Thanks again!
Checking if the user has permissions to a project on every request is the correct solution. Consider cases when many other applications / users are calling your API. You want to make sure that your API is as secure as possible and cannot be manipulated from the frontend.
To make it more efficient you should have a way/query to check associations in your database like a simple query that returns true/false which should be quicker than retrieving all the data and comparing in Java code.
And when possible combine multiple database queries into one, like for one of your examples:
GET /api/v1/projects/{projectId}
in this case, don't run a query to get a user's information and a query for the requested project. Instead you could do a single query with a join between the user's table and the project table which should only return a project if the user is associated with it. The best way really depends on how your database is structured.
Adding a user id into the API URL is just redundant information. Just because the user id in the token matches the user id in the URL doesn't mean the user has any kind of permissions to any project.
Another solution to be avoided is to include the user's project ids in the JWT token which you can then compare without making a database request. This is bad for several reasons:
The token should only have required information for the user to access the API, it shouldn't have business logic
Depending on how much business logic you store in the token the token can become large in size. See this post for a discussion on size limits: What is the maximum size of JWT token?
If there is a way for the someone other than the user (like admin) to add/remove a user's association to a project then that change will not be reflected in the token until the token's data is refreshed
EDIT:
On the spring side I have used the #PreAuthorize annotation before to handle these types of method checks. Below is pseudo code as an example.
#RestController
public class MyController {
#PostMapping
#PreAuthorize("#mySecurityService.isAllowed(principal, #in)")
public SomeResponseType api1(SomeRequestType requestData) {
/* this is not reached unless mySecurityService.isAllowed
returns true, instead a user gets a 401/403 HTTP response
code (i don't remember the exact one) */
}
}
#Service
public class MySecurityService {
/*
Object principal - this is spring's UserDetails object that is
returned from the AuthenticationProvider. So basically a Java
representation of the JWT token which should have the
user's username.
SomeRequestType requestData - this is the request data that was
sent to the API. I'm sure there is a way to get the project ID
from the URL here as well.
*/
public boolean isAllowed(Object principal, SomeRequestType requestData) {
/*
take the user's username from the principal, take the
project ID from the request data and query the database
to check authorization, return true if authorized
make this check efficient
*/
return false;
}
}
The annotation and the security service can then be applied to multiple methods. You can have many different security services depending on what your are checking.
There are other ways available too https://www.baeldung.com/spring-security-method-security and this has to be enabled in spring's configuration (also explained in the link).
Hi so if I understood it correctly you want to automatically assign the task that is going to be created with "POST /api/v1/projects/{projectId}/tasks" to the current logged in user.
You could try to add a Parameter 'Principal principal' to your rest controller. The Principal is the user that is sending the request.
After you have your Prinicipal, you could write a simple convert method(for example: convertPrincipalToUser(Principal principal) which returns you the user. Finally you can add your user to the corresponding task)
Here is some more information about it:
https://www.baeldung.com/get-user-in-spring-security

How to get more/optional data for users using keyclaok rest api?

We are using Keycloak for SSO purpose, in particular we are able to use the REST API /admin/realms/{realm}/users to get the basic user details in a Keycloak realm, the response we get is UserRepresentation which seems to have provision for realmRoles and clientRoles as well but by default they are not required/false.
We have a new requirement to fetch the roles of all users, I see there are additional API exposed to get these roles: /auth/admin/realms/realm/users/user-id/role-mappings/realm/, but this means firing another request, and if we have 2k users that means 2k more request.
My question is as UserRepresentation also have properties realmRoles and clientRoles but seems to be optional by default, how can I enable these while firing the request /admin/realms/{realm}/users, and avoid additional request to get roles.
I'm afraid that getting the data you need in one request is not possible: just by looking at the source code of getting all users in UsersResource you can see that realmRoles and clientRoles are never populated.
Having that said, there is one thing that you can do - write your own REST Resource by implementing SPI. In fact, in the past I had a similar problem with groups resource and I ended up writing my own resource. In this case you will need to write custom resource with just one method - getting all users with roles. You can just copy-paste current keycloak logic and add extra bits or extend built-in UsersResource. This, however, is not a single bullet - on the long run you will be required to maintain your own code and upgrades to latest keycloak may not be that simple if some interface will change.

Get logged in userId from a 'me' relative id in /users/me spring boot api

We have a bunch of secured web services (using spring security) defined like this:
#GetMapping("/users/{userId}")
public User getUserInfo(#PathVariable String userId) {
...
#GetMapping("/users/{userId}/addresses")
public User getUserInfo(#PathVariable String userId) {
If I want to get the logged in user, I can add the Principal principal or HttpServletRequest request to the method and spring will support the data for the logged in user, or also I can use SecurityContextHolder.getContext().getAuthentication().
So far so good, if we want to get the logged in user for the api /users/1234 we have no problem. However we got a requirement to support a relative userId value being me where the api would be /users/me.
We could resolve this by adding in each api just an if statement and replacing the userId me with the real logged in userId. We don't like this implementation since we have a boilerplate code in 20 apis. So, another solution we tried was by just adding an aspect to replace the me by the real userId but I don't like using reflection for solving this problem.
So, i was wondering if there is a "spring boot" way of doing this? I haven't found any feature supporting this behavior.
I think the best solution would be to change that URL. If statement is ver explicit too though. There are interceptors as well you could use but I don't see them as being much different to using aspects, pretty evil stuff. But if you do use aspects I would suggest that you have an annotation such as #Me which you could annotated method inputs such as userId with, which would replace them with the id of the principal if the parameter is equal to me.

Securing REST services in Jersey

I am very much new to web services. I have exposed some REST services using Jersey 2 in integration with Spring. Now I need to secure those rest services using authentication with username/password. I am told not to use Spring Security.
I have no idea of how to do this. I did search on the net but various links show various implementation and I am unable to decide how to proceed with it.
A common way for authenticating with username and password is to use Basic Authentication. Basically the client needs to send a request header Authorization, with the the header value as Basic Base64Encoded(username:password). So is my username is peeskillet and my password is pass, I, as a client, should set the header as
Authorization: Basic cGVlc2tpbGxldDpwYXNz
In a servlet environment, the container should have support for Basic authentication. You would configure this support on the web.xml. You can see an example in 48.2 Securing Web Applications of the Java EE tutorial. You will also notice in an example
<transport-guarantee>CONFIDENTIAL</transport-guarantee>
That is for SSL support. This is recommended for Basic Authentication.
If you don't want to deal with the hassle of working with security domains and login modules, realm, and such, that would be required to customize the servlet support, or if you're just not in a servlet environment, implementing Basic Auth in a ContainerRequestFilter is really not too difficult.
You can see a complete example of how this could be done at jersey/examples/https-clientserver-grizzly. You should focus on the SecurityFilter
The basic flow in the filter goes something like this
Get the Authorization header. If it doesn't exist, throw an AuthenticationException. In which case the AuthenticationExceptionMapper will send out the header "WWW-Authenticate", "Basic realm=\"" + e.getRealm() + "\", which is part of the Basic Auth protocol
Once we have the header, we parse it just to get the Base64 encoded username:password. Then we decode it, then split it, then separate the user name and password. If any of this process fails, again throw the WebApplicationException that maps to a 400 Bad Request.
Check the username and password. The example source code just checks if the username is user and the password is password, but you will want to use some service in the filter to verify this information. If either of these fail, throw an AuthenticationException
If all goes well, a User is created from the authenticate method, and is injected into an Authorizer (which is a SecurityContext). In JAX-RS, the SecurityContext is normally used for authorization`.
For the authorization, if you want to secure certain areas for certain resources, you can use the #RolesAllowed annotation for your classes or methods. Jersey has support for this annotation, by registering the RolesAllowedDynamicFeature.
What happens under the hood is that the SecurityContext will be obtained from the request. With the example I linked to, you can see the Authorizer, it has an overridden method isUserInRole. This method will be called to check against the value(s) in #RolesAllowed({"ADMIN"}). So when you create the SecurityContext, you should make sure to include on the overridden method, the roles of the user.
For testing, you can simply use a browser. If everything is set up correctly, when you try and access the resource, you should see (in Firefox) a dialog as seen in this post. If you use cURL, you could do
C:/>curl -v -u username:password http://localhost:8080/blah/resource
This will send out a Basic Authenticated request. Because of the -v switch, you should see all the headers involved. If you just want to test with the client API, you can see here how to set it up. In any of the three cases mentioned, the Base64 encoding will be done for you, so you don't have to worry about it.
As for the SSL, you should look into the documentation of your container for information about how to set it up.
So this is really a matter what you would like to achieve. My case was to get this thing running with mobile and a One-Page-App JavaScript.
Basically all you need to do is generate some kind of header that value that will be needed in every consecutive request you client will make.
So you do a endpoint in which you wait for a post with user/password:
#Path("/login")
public class AuthenticationResource {
#POST
#Consumes("application/json")
public Response authenticate(Credentials credential) {
boolean canBeLoggedIn = (...check in your DB or anywher you need to)
if (canBeLoggedIn) {
UUID uuid = UUID.randomUUID();
Token token = new Token();
token.setToken(uuid.toString());
//save your token with associated with user
(...)
return Response.ok(token).type(MediaType.APPLICATION_JSON_TYPE).build();
} else {
return Response.status(Response.Status.UNAUTHORIZED).build();
}
}
}
Now you need to secure resource with need for that token:
#Path("/payment")
#AuthorizedWithToken
public class Payments {
#GET
#Produces("application/json")
public Response sync() {
(...)
}
}
Notice the #AuthorizedWithToken annotation. This annotaation you can create on your own using special meta annotation #NameBinding
#NameBinding
#Target({ElementType.METHOD, ElementType.TYPE})
#Retention(RetentionPolicy.RUNTIME)
public #interface AuthorizedWithToken {}
And now for the filter that implements checking of the header:
#AuthorizedWithToken
#Provider
public class XAuthTokenFilter implements ContainerRequestFilter {
private static String X_Auth_Token = "X-Auth-Token";
#Override
public void filter(ContainerRequestContext crc) throws IOException {
String headerValue = crc.getHeaderString(X_Auth_Token);
if (headerValue == null) {
crc.abortWith(Response.status(Response.Status.FORBIDDEN).entity("Missing " + X_Auth_Token + " value").build());
return;
}
if(! TOKEN_FOUND_IN_DB) {
crc.abortWith(Response.status(Response.Status.UNAUTHORIZED).entity("Wrong " + X_Auth_Token + " value").build());
return;
}
}
}
You can create any number of your own annotations checking for various things in the http request and mix them. However you need to pay attention to Priorities but that actually easy thing to find. This method needs using https but that is obvious.
Security comes in two main flavours :
Container Based
application based
the standard way to secure spring applications is to use Spring Security (formerly Acegi).
It would be interesting to know why you're not being allowed to use that.
You could use container based security, but I'm guessing that your use of spring precludes that option too.
Since the choice of Spring is usually to obviate the need for the use of a full J2EE container (Edit : though as pointed out below by others, most ordinary servlet containers do allow you to implement various container based security methods)
This really only leaves you with one option which is to roll your own security.
Your use of Jersey suggests that this might be a REST application.
In which case you really ought to stick with standard HTTP Authentication methods that
comes in the following flavours in reverse order of strength :
BASIC
Digest
Form
Certificate
REST applications are usually supposed to be 'stateless', which essentially rules out form based authentication (because you'd require the use of Session)
leaving you with BASIC, Digest and Certificate.
Your next question is, who am I authenticating. If you can expect to know the username AND the password of the user based on what URL they requested (say if it's one set of credentials for all users) then Digest is the best bet since the password is never sent, only a hash.
If you cannot know the Password (because you ask a third party system to validate it etc.) then you are stuck with BASIC.
But you can enhance the security of BASIC by using SSL, or better yet, combining BASIC with client certificate authentication.
In fact BASIC authentication over HTTPS is the standard technique for securing most REST applications.
You can easily implement a Servlet Filter that looks for the Authentication Header and validates the credentials yourself.
There are many examples of such filters, it's a single self contained class file.
If no credentials are found the filter returns 401 passing a prompt for basic auth in the response headers.
If the credentials are invalid you return 403.
App security is almost an entire career in itself, but I hope this helps.
As the former posts say, you could go with different options, with a varying overhead for implementation. From a practical view, if you're going to start with this and are looking for a comfortable way for a simple implementation, I'd recommend container-based option using BASIC authentication.
If you use tomcat, you can setup a realm, which is relatively simple to implement. You could use JDBCRealm, which gets you a user and password from specified columns in your database, and configure it via server.xml and web.xml.
This will prompt you for credentials automatically, everytime you are trying to access your application. You don't have any application-side implementation to do for that.
What I can tell you now is that you already did most of the 'dirty' job integrating Jersey with Spring. I recommend to you to go an Application-based solution, is it does not tie you to a particular container. Spring Security can be intimidating at first, but then when you tame the beast, you see it was actually a friendly puppy.
The fact is that Spring Security is hugely customizable, just by implementing their interfaces. And there is a lot of documentation and support. Plus, you already have a Spring based application.
As all you seek is guidance, I can provide you with some tutorials. You can take advantage from this blog.
http://www.baeldung.com/rest-with-spring-series/
http://www.baeldung.com/2011/10/31/securing-a-restful-web-service-with-spring-security-3-1-part-3/

Protecting resources such as images in a servlet

Let's say that you have an image I that you only want users who have logged into your website to be able to see. What is the best way to protect I from non-logged in users. One possible way is to have a page where you pass the image name via get or post parameters, and it would return the image by reading the image from disk and writing back in the response based on if the user was logged in the session. Is/Are there better ways to achieve security of resources more efficiently?
use your session. when the user is logged in, you load the image to your page.
There are couple easy ways you could to this with servlet filters or just plain servlet that servers your resource.
Personally I would check if the principal have been set is so then you know the user is authenitcated
Principal principal = request.getUserPrincipal();
if (principal == null) {
return null;
}
If there is no principal you know the user is not authenticated, you could return 403 status, blank image or whatever you like.
If you want to protect the urls of the image files, set some rules about their access in your code. I think a better alternative is using some security framework. There are some security platforms like Spring Security provide very comprehensive access rules based on user authentication status, url-role combination, and acl, etc..

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