Securing JSON-PATCH paths in Spring Boot Data Rest application - java

I'm using a pretty vanilla spring-boot-starter-data-rest setup and enabled the PATCH method. All is working, but I have a security concern and wonder what's the recommended way of mitigating it.
The problem is that PATCH paths allow reachable entities to be updated from a different endpoint. So, suppose I have a comments endpoint and an article endpoint. Each comment has a to-one association with its article. A user that has permission to edit a comment could then do something like this:
PATCH http://some.domain.foo/api/comments/1234
Content-Type: application/json-patch+json
[
{ "op": "replace", "path": "/article/title", "value": "foobar2" }
]
and thereby change the title of the article !!
Clearly this ain't good.
In this case, for other parts of the API the association to the "article" needs to be traversable. But it must be read-only.
So... how do I accomplish this in Spring?
Intercept the request?
Implement a handler method?
Write my own Controller from scratch ?
Thanks!

Seems that current implementation on spring-data-rest converts paths to SpEL to apply values directly on beans. See PatchOperation (v2.5.x).
Consider these options:
Instead of json-patch use json-merge PATCH request to send partial updates (with "application/json" or "application/merge-patch+json" content type). This will respect #JsonIgnore and other Jackson annotations and also treat associations differently.
You can disable "json-patch+json" completely, for example by adding a security filter
You can always create your custom json-patch implementation, if you still need it
Use application-level joining not relying on JPA, i.e. only exposing IDs of the linked entities and providing custom links in your ResourceProcessor.
Additionally, if you're using JPA and Comment.article is annotated with #ManyToOne make sure that there's no cascading on association. Even if the article object is modified with patch it won't be saved together with the comment.

There's been a recent fix in Spring Data Rest:
https://github.com/spring-projects/spring-data-rest/issues/2177
The commit that resolves this issue is:
https://github.com/spring-projects/spring-data-rest/commit/5d0687d1a1bb9a84264ecb4cd088907837c382d3
From a quick read this seems to be checking that when applying a JSON patch to an entity a check is done with Jackson that the path should be accessible (read/write).
This should prevent users from being able to specify paths in the JSON patch that aren't normally exposed through POST/GET requests that are mapped directly onto entities through Jackson. I think that if you had marked the article as readable from the comment and the title attribute as writeable then the new code should allow it. Or that's I think what org.springframework.data.rest.webmvc.json.patch.JsonPointerMapping#verify is trying to do.
So if you marked the article on the comment as not being readable through Jackson (#JsonIgnore on the getter) then JSON patch shouldn't allow the title of the article to be set through a comment. The association would still exist, just not be exposed through JSON serialization, I'm not sure if this would cause problems for your application.
The change is released in Spring Data Rest 4.0.0 which is part of Spring Data 2022.0.1 which is in Spring Boot 3.0.2.
https://github.com/spring-projects/spring-data-rest/releases/tag/4.0.0
https://github.com/spring-projects/spring-data-bom/releases/tag/2022.0.1
https://github.com/spring-projects/spring-boot/releases/tag/v3.0.2

Related

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.

Shiro throws an UnavailableSecurityManagerException in custom JSON serialiser

I'm working on a REST API of a TomEE 7 based web app, which uses Shiro 1.3.2 for security. When an API request comes in, a SecurityManager and a Subject are created, and the latter is bound to a SubjectThreadState. I can call SecurityUtils.getSubject() anywhere in the endpoint code and the subject is always available.
However, problems arise when I try to do the same inside my custom JSON serialiser. It only serialises specific fields in some classes, so I register it on a per-field basis using this annotation:
#JsonSerialize(using = MySerialiser.class)
Long myRelatedItemId;
I wrote my serialiser based on the example code on this page under "2.7. #JsonSerialize". The serialiser needs to perform a cache lookup, and for that it has to have a Shiro subject. There is none because, thanks to the annotation above, I don't call the serialiser manually; instead Jersey calls it. This exception gets thrown (clarification: when I try to run SecurityUtils.getSubject() from the serialiser code):
org.apache.shiro.UnavailableSecurityManagerException: No SecurityManager accessible to the calling code, either bound to the org.apache.shiro.util.ThreadContext or as a vm static singleton. This is an invalid application configuration.
at org.apache.shiro.SecurityUtils.getSecurityManager(SecurityUtils.java:123)
at org.apache.shiro.subject.Subject$Builder.<init>(Subject.java:627)
at org.apache.shiro.SecurityUtils.getSubject(SecurityUtils.java:56)
I have confirmed that everything works if I call something like ObjectMapper().writeValueAsString() manually from the API endpoint code. However, that is definitely not the proper way to do it, because then the endpoint would effectively send and receive strings instead of the objects they are meant to handle.
I don't understand much about the inner workings of Shiro or Jackson, but it seems like the serialisation is being performed inside another thread, where Shiro's SubjectThreadState doesn't exist. Although if threading really is the cause, then I cannot see why Thread.currentThread().getName() returns the same value both inside and outside the serialiser, as does Thread.currentThread().getId().
I have tried a vast number of things to no avail, including:
Upgrading to Shiro 1.4.0.
Upgrading Jackson from 2.7.5 to 2.9.7.
Saving the SecurityManager instance that is created at the start of the API call inside a static ThreadLocal variable of the serialiser class.
Writing my own implementation of MessageBodyWriter which, not surprisingly, is called in exactly the same fashion.
Setting the staticSecurityManagerEnabled parameter to true in the ShiroFilter configuration in my web.xml.
Can anyone suggest how I could make the SecurityManager (or Subject) visible to the serialiser, when it's running in a thread not started by my code (clarification: or, otherwise running in parallel and started by Jersey, as far as I can tell)? Thanks in advance.
Update:
This stack trace was taken inside the serialiser:
<mypackage>.MySerializer.serialize()
com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField()
com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields()
com.fasterxml.jackson.databind.ser.BeanSerializer.serialize()
com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue()
com.fasterxml.jackson.databind.ObjectWriter$Prefetch.serialize()
com.fasterxml.jackson.databind.ObjectWriter.writeValue()
com.fasterxml.jackson.jaxrs.base.ProviderBase.writeTo()
org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.invokeWriteTo()
org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo()
org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed()
org.glassfish.jersey.server.internal.JsonWithPaddingInterceptor.aroundWriteTo()
org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed()
org.glassfish.jersey.server.internal.MappableExceptionWrapperInterceptor.aroundWriteTo()
org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed()
org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo()
org.glassfish.jersey.server.ServerRuntime$Responder.writeResponse()
org.glassfish.jersey.server.ServerRuntime$Responder.processResponse()
org.glassfish.jersey.server.ServerRuntime$Responder.process()
org.glassfish.jersey.server.ServerRuntime$2.run()
This one was taken in our interceptor class where the Subject is created and bound:
<mypackage>.MySecurityInterceptor.createSession()
sun.reflect.NativeMethodAccessorImpl.invoke0()
sun.reflect.NativeMethodAccessorImpl.invoke()
sun.reflect.DelegatingMethodAccessorImpl.invoke()
java.lang.reflect.Method.invoke()
org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke()
org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed()
org.apache.openejb.monitoring.StatsInterceptor.record()
org.apache.openejb.monitoring.StatsInterceptor.invoke()
sun.reflect.GeneratedMethodAccessor111.invoke()
sun.reflect.DelegatingMethodAccessorImpl.invoke()
java.lang.reflect.Method.invoke()
org.apache.openejb.core.interceptor.ReflectionInvocationContext$Invocation.invoke()
org.apache.openejb.core.interceptor.ReflectionInvocationContext.proceed()
org.apache.openejb.core.interceptor.InterceptorStack.invoke()
org.apache.openejb.core.stateless.StatelessContainer._invoke()
org.apache.openejb.core.stateless.StatelessContainer.invoke()
org.apache.openejb.core.ivm.EjbObjectProxyHandler.synchronizedBusinessMethod()
org.apache.openejb.core.ivm.EjbObjectProxyHandler.businessMethod()
org.apache.openejb.core.ivm.EjbObjectProxyHandler._invoke()
org.apache.openejb.core.ivm.BaseEjbProxyHandler.invoke()
com.sun.proxy.$Proxy279.getEntity()
org.openapitools.api.impl.MyApiServiceImpl.getEntity()
org.openapitools.api.MyApi.getEntity()
sun.reflect.NativeMethodAccessorImpl.invoke0()
sun.reflect.NativeMethodAccessorImpl.invoke()
sun.reflect.DelegatingMethodAccessorImpl.invoke()
java.lang.reflect.Method.invoke()
org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke()
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run()
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke()
org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$ResponseOutInvoker.doDispatch()
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch()
org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke()
org.glassfish.jersey.server.model.ResourceMethodInvoker.apply()
org.glassfish.jersey.server.model.ResourceMethodInvoker.apply()
org.glassfish.jersey.server.ServerRuntime$2.run()
There are 46 more calls that are identical in both traces after that last line, so I excluded them. They contain a bunch of org.apache.catalina.core and org.glassfish.jersey.
Take a look at Shiro's Subject Thread Association doc

Understanding the flow of spring framework & MVC

I am having some trouble understanding this. Can someone help me better understand this?
MVC
Model --> Java- Spring Framework
View ---> templating language(JSP velocity) & Javascript
DB --> SQL
Q-1)
Now, When I open a particular page, I can't visualize the flow. I've read about DAO, controller , service etc and I understand them individually but I am really confused when I club all together what's the order of execution? Whats the flow exactly ? Is it that first the view is loaded then it sends JS request to fetch the necessary data from backend and then the controller and service are invoked and the DAO queries the db? Then how does the API come into picture? DAO deals with the API?
Q-2)
Why do we need xyz.properties? I have removed a module from my page. If I remove a particular js file(related to that module) from the scripts.properties, then ideally that js should not get executed at all right? Then still why would I see the api call to fetch the data related to that module? I don't see the module but I sure see the api call. Why is that?
DB doesn't enter in MVC model. And you're forgetting a principal element in your analysis: the Controller. The flow goes like this:
Client performs a request to an URL
The application server gets the URL and passes the handling to the web application.
The web application using Spring MVC will handle the URL processing to the Controller: DispatchServlet, which is a Servlet.
The DispatchServlet will try handle the URL. If there's an URL mapping, then it will pass it to the class (mapped in the spring.xml config or decorated with #Controller annotation).
This controller (which in fact is part of the model) will handle the request. It will call services, daos, etc (Model) and return the necessary data to complete the response to the DispatchServlet.
The DispatchServlet will finish the request handling and, in the end, will generate the results e.g. a text/json response, or it will forward to a JSP file (View).
For question two, I never have used such scripts.properties file, so I don't know what you're talking about. Usage of a properties file is to store application properties that should not change until an application redeploy. They have 3 main advantages:
They can be easily manipulated by human users. It's no rocket science to add, edit or remove values.
Since it is a plain text, it's easier to version using a version control system like SVN, Git or another of your preference.
It provides a faster access since it is usually in the same disk as the application, so there's no much time penalty when accessing to its contents compared to a database configuration. But since it is in disk, it still has a disadvantage against RAM access only.
In simple layman's term, MVC explained in pictorial form
(inputing data) (data related part) (display rendering)
-request mapping -classes -JSP (Script,CSS,HTML)
-request param -interface -velocity
Controller ------------->Model--------------->View
||
\/
(data processing logic) (access to Databse)
-optimization -JDBC
-business logic -SQL
Service--------------------->DAO

Spring Security ACL tags for REST Services

I am new to Posting question in Stack Overflow.
I am currently implementing Spring Security ACL for my REST Services.
What i want is a way to hide and show certain UI tags based on ACL entry.
Since i am using REST Services - All my calls from UI are ajax based and returns a JSON.
Now with Spring Security ACL tags its required to send a DomainObject to the tag so that it can resolve the authorization.
Since i get a JSON from backend i cant create a DomainObject.
Also the time i return a JSON to frontened the JSP will be delivered in first place so the security tag will not be effected.
Best Regards
Sriram
I solved this by returning a json which will have crud variables marked true or false depending on the users access control and in the ui I show/hide using this data.

Spring MVC Request mapping, can this be dynamic/configurable?

With Spring MVC, I know how you set the RequestMapping in every controller and method/action.
But what if I wanted this to be configurable, so for example I the following controllers:
BlogController
- with methods for listing blogs entries, single entry, new, update, etc.
ArticleController
- with methods for listing articles entries, single entry, new, update, etc.
Now in my application, the administrator can setup 2 blogs for the webiste, and 1 article section so the urls would be like:
www.example.com/article_section1/ - uses ArticleController
www.example.com/blog1/ - uses BlogController
www.example.com/blog2/ - uses BlogController
Maybe after a while the administrator wants another article section, so they just configure that with a new section like:
www.example.com/article_section2/
This has to work dynamically/on-the-fly without having to restart the application of course.
My question is only concerned with how I will handle url mappings to my controllers.
How would this be possible with Spring MVC?
I only know how to map urls to controllers using #RequestMapping("/helloWorld") at the controller or method level, but this makes the url mappings fixed and not configurable like how I want it.
Update:
I will be storing the paths in the database, and with the mapping to the type of controller so like:
path controller
/article_section1/ article
/blog1/ blog
/blog2/ blog
..
With the above information, how could I dispatch the request to the correct controller?
Again, not looking to reload/redeploy, and I realize this will require more work but its in the spec :)
Would this sort of URL mapping work for you?
www.example.com/blog/1/
www.example.com/blog/2/
If yes, then that's easy: Spring 3 supports path variables: http://static.springsource.org/spring/docs/3.0.x/reference/mvc.html#mvc-ann-requestmapping-advanced
Alternatively, you can create a generic request mapping and your own sub-dispatcher that reads a config file, but I think that's probably more work than it's worth.
Truly changing the request mappings at runtime might be hard (and not really recommended, since small errors can easily occur). If you still wish to do it, perhaps JRebel, and more specificly LiveRebel can be interesting for live redeployment of code and configuration.
Otherwise, like other posts suggested, RequestMappings supports wildcards, the limits of this should be clear after a quick read of the official documentation.
Try using with #RequestMapping wild cards as below:
#RequestMapping(value="/article_section*/"}
public void getArticle(....){
//TODO implementation
}
#RequestMapping(value="/blog*/"}
public void getBlog(....){
//TODO implementation
}
Hope this helps!!!
Also another solution might be to create a custom annotation that holds the already defined path on the #RequestMapping and also the new one to apply, let's say #ApiRestController.
Then, before the Spring context loads, the #Controller classes can be changed to have their annotation values changed at runtime by the new one (with the desired path). By doing this, Spring will load the enhanced request mapping and not the default one.
Created a small project to exemplify this for someone that needs this in the future https://gitlab.com/jdiasamaro/spring-api-rest-controllers.
Hope it helps.
Cheers.
doesn't this work?
#RequestMapping("/helloWorld*")

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