Bridge Authorization Rules

The Solution

We implemented an AuthEvaluator class that can be used to describe static objects that will check our different authorization rules. (Sometimes we still need to do a verification on models returned from the system, which are not covered…e.g. “is this object you loaded associated to the study we just verified you have access to?”)

The AuthEvaluator rules can be called in the controllers, then it’s much easier to find the authorization rule for a given API endpoint when writing SDK documentation. The evaluator currently has an overly-broad rule that needs to be removed for more specific checks:

BRIDGE-2897 - Getting issue details... STATUS

Bridge Roles

ADMIN - all authorization checks should succeed for ADMINs. They should be excepted in the AuthEvaluator, then they can be removed from getSession(…) checks.

A SUPERADMIN is an ADMIN in all respects, but who has APIs to switch between apps without an account in each app (UserManagementController.signInForSuperAdmin and AuthenticationController.changeApp). Admin and Superadmin SDK clients can just define the APIs, like the cache or app creation APIs, that are only available to those roles, since all the other clients will work and succeed for these users.

This is not fully or consistently implemented, see:

BRIDGE-2898 - Getting issue details... STATUS

DEVELOPER, RESEARCHER - These divide the APIs between calls to configure an app and calls to return information about study participants (include PII). They are app-scoped, and too broad for apps that have multiple studies run by different researchers.

We might choose to allow these roles access to their study-scoped alternates (described below). They would then be supersets of those roles. See:

BRIDGE-2899 - Getting issue details... STATUS

STUDY COORDINATOR - This is a study-scoped version of a researcher (they can only access studies that they have access to through their organization). This person may be able to do other things, like set up schedules for a study.

STUDY DEVELOPER - This is a study-scoped version of a developer. It’s not clear yet if it will be needed (coordinators might be able to configure everything about a study and we aren’t going to let outside developers muck about with app configuration).

BRIDGE-2896 - Getting issue details... STATUS

ORGANIZATION ADMINISTRATOR - This is an administrator of an organization, that can edit an organization, including creating accounts in the organization. They or their users can in turn create studies that are sponsored by, and accessible to, all organization members.

The Problem (original issues that led to this design)

In adding Mobile Toolbox to Bridge, we’re encountering more complex authorization. We have roles like an organization administrator, who can create users who are members of their organization (but who cannot see any other kind of accounts, including study participants in their organization’s studies), and study designers, who can edit some of the things that a developer can edit…but only in the context of the studies they have access to.

Right now these checks are spread out:

Controllers usually check for roles and consent;
AuthUtils methods are called in the services to check the relationship of the caller to entities like studies and organizations.

This is getting messy. The issues I feel I’m encountering

Security is defined in different places, there’s not one place to see what is and is not permissible;
Utility methods are difficult to compose into new requirements and despite my best attempts, the names of these things rename confusing at times;
Consequently it’s hard to say we don’t have lapses in the authorization checks that are occurring.

I think we could use a more robust alternative to implement this. But first, here are the authorization checks we have implemented or want to implement in the MTB timeframe (described in terms of access to objects in the REST API, rather than through the several endpoints that are needed to expose each object in the API itself, and skipping participant-facing APIs). Then as well look at alternatives for implementation, I’ll show what modeling enrollment would look like.

Authorization Rules

Object	Assoc(1)	Role	Permissions(2)

Object	Assoc(1)	Role	Permissions(2)
AccountSummary	global (but filtered)	researcher	read
	Study (“participant”)	researcher	read
	Organization (“member”)	org admin	read
App		all	read
		dev, admin	update
		superadmin	create, delete
AppConfig		public	read (filtered)
		dev	create, read, write, delete
AppConfigElement		dev	create, read, write, delete
Assessment	Organization (“owner”)	dev	create, read, write
		admin	delete
AssessmentConfig		public	read
	Organization (“owner”)	dev	write
Enrollment(Detail)	Account (“self”)	any	create, read, delete
	Study	researcher	create, read, delete
	Study	admin	create, read, delete
AssessmentResource	Organization (“owner”)	developer	create, read, delete
		admin	delete
FileMetadata/Revision		developer	create, read, write
		admin	delete
HealthDataRecord(Ex3)		participant	create
		worker	write
MasterScheduleConfig		superadmin	create, read, write, delete
NotificationMessage		self, admin, researcher	create
NotificationRegistration		self, researcher, admin	read
NotificationTopic		developer	create, read, write
		admin	delete
Organization		any	read
	Account (“membership”)	org_admin	write
		admin	create, delete
RecordExportStatusRequest		worker	write
ReportData	Study	any/public	read
	Study	dev, worker	create, delete
ReportIndex	Study	any	read
	Study	dev	create, write
RequestInfo	Account (“self”)
RequestInfo	Study	researcher	read
		admin, worker	read
SchedulePlan		developer, researcher, worker	read
		developer	create, write
		admin	delete
SmsTemplate	Account	worker	create
Study		org_admin	create
	Organization (“sponsors”)	org_admin	create, read, delete
StudyConsent		dev	create, read
StudyParticipant	Study (“enrolled”)	researcher	create, read, write
		worker	read
	Participant (“self”)		read, write
		admin	create
Subpopulation		dev	create, read, write
		researcher	read
		admin	delete
Survey		dev, researcher, worker	read
		dev	create, write
		admin	delete
Tag		public	read
		superadmin	create, delete
Template/TemplateRevision		dev	create, read, write
		admin	delete
Upload		dev, admin, worker	read
UploadSchema		dev	create, read, write
		admin	delete

(1) = association to another model object. This typically means an additional check to ensure is a member of an organization, or has access to a study through their organization, or is the target of the call as well as the caller, and so forth. If blank, then the association is to an app, because everything is scoped/tenanted to an app.

(2) C = create/write, R = read (list or detail object), U = update/write/delete logically, D = delete physically.

Here are objects from the v2 domain model that have been designed far enough to think about permissions (designer = STUDY_DESIGNER):

Object	Assoc	Role	Permissions

Object	Assoc	Role	Permissions
Protocol/Study Arms	Organization (“owner”)	designer, developer	create, read, write
	Study	designer, developer	read
		admin	delete
Schedule	Study (“owner”)	designer, developer	create, read, write
		admin	delete
Study Arm Schedule	Organization (“owner”)	designer, developer	create, read, delete

Spring Security

This is the most complex option available, but we could use the method-based security via annotations. Our service methods could declare the security using complex expression rules.

Modeling EnrollmentService, it would look like this (ignoring the work necessary to make it work):

public class EnrollmentService {

    @Secure("principal.id == userId or hasRole('ADMIN') or " + 
      "(hasRole('RESEARCHER') and hasOrgSponsoredStudy(studyId))")
    public PagedResourceList<EnrollmentDetail> getEnrollments(...) {
    }
    
    @Secure("principal.id == userId or hasRole('ADMIN') or " + 
      "(hasRole('RESEARCHER') and hasOrgSponsoredStudy(studyId))")
    public Enrollment enroll(...) {
    }
    
    @Secure("principal.id == userId or hasRole('ADMIN') or " + 
      "(hasRole('RESEARCHER') and hasOrgSponsoredStudy(studyId))")
    public void updateEnrollment(...) {
    }
    
    @Secure("principal.id == userId or hasRole('ADMIN') or " + 
      "(hasRole('RESEARCHER') and hasOrgSponsoredStudy(studyId))")
    public Enrollment unenroll(...) {
    }
}

Pros

It’s a standardized thing so other developers should have an easier time working with it;
Ultimately, security would be expressed in annotations, which seems nice;
One step closer to implementing a major change to something like storing access rights in a database (so far we haven’t seen anything in Bridge that requires that level of authorization, but)

Cons

Our existing authentication and authorization have all been written from scratch, which means we’d need to overwrite all the core Spring Security classes before any of this would work;
The result would take time and involve learning a lot more about Spring Security;
Security exceptions would appear in places where we are now able to return InvalidEntityExceptions and the like. For example empty/null/imaginary values are going to throw security exceptions. (I’m fine with this).

Implement a DSL

Nothing Spring does is that hard to duplicate with a DSL that uses our existing RequestContext. I think it makes sense to call these in the services, where multiple endpoints might create multiple conditions under which a call is acceptable. It could look something like this:

public class EnrollmentService {
    private static final AuthEvaluator SELF_ADMIN_OR_STUDY_RESEARCHER = 
        AuthUtils.canAccessStudy().inRole(RESEARCHER).or()
            .inAnyRole(ADMIN, SUPERADMIN).or()
            isSelf();

    public PagedResourceList<EnrollmentDetail> getEnrollments(...) {
        SELF_ADMIN_OR_STUDY_RESEARCHER.checkAndThrow("studyId", studyId, "userId", userId);
    }
    
    public Enrollment enroll(...) {
        SELF_ADMIN_OR_STUDY_RESEARCHER.checkAndThrow("studyId", studyId, "userId", userId);
    }
    
    public void updateEnrollment(...) {
        SELF_ADMIN_OR_STUDY_RESEARCHER.checkAndThrow("studyId", studyId, "userId", userId);
    }
    
    public Enrollment unenroll(...) {
        SELF_ADMIN_OR_STUDY_RESEARCHER.checkAndThrow("studyId", studyId, "userId", userId);
    }
}

Pros:

Easier to implement and understand at this point, when compared with overriding Spring Security’s implementation classes
Arguably, easier to understand because it’ll only contain what it necessary for our application (as opposed to Spring which is always more complicated because it can handle anything, including future requirements).

Cons:

More custom code for new developers to learn (assuming they already know Spring security which is more portable for them anyway);
We’re bearing down further on a custom implementation making that much harder later if we decide to abandon it for anything else. If we’re going to switch, better to switch sooner.

Recommit to implementing authorization in the controllers

Arguably we can continue to use authorization in the controllers if we just create more endpoints that are tailored to our specific authorization scenarios.

Take the example of AuthUtils.checkSelfStudyResearcherOrAdmin check for enrollments:

public class EnrollmentService {

    @GetMapping("/v5/studies/{studyId}/enrollments")
    public PagedResourceList<EnrollmentDetail> getEnrollments(...) {
        UserSession session = getAuthenticatedSession(RESEARCHER, ADMIN);

        if (!session.isInRole(ADMIN) && !AuthUtils.canAccessStudy(studyId)) {
          throw new UnauthorizedException();
        }
    }
    
    @GetMapping("/v3/participants/self/enrollments")
    public PagedResourceList<EnrollmentDetail> getSelfEnrollments(...) {
        UserSession session = getAuthenticatedSession();
        // set userId to the caller's user Id
    }

    @PostMapping("/v5/studies/{studyId}/enrollments")
    public Enrollment enroll(...) {
        UserSession session = getAuthenticatedSession(RESEARCHER, ADMIN);

        if (!session.isInRole(ADMIN) && !AuthUtils.canAccessStudy(studyId)) {
          throw new UnauthorizedException();
        }
    }

    @PostMapping("/v3/participants/self/enrollments")
    public Enrollment enrollSelf(...) {
        UserSession session = getAuthenticatedSession();
        // set userId to the caller's user Id
    }

    @PostMapping("/v5/studies/{studyId}/enrollments/{userId}")
    public void updateEnrollment(...) {
        UserSession session = getAuthenticatedSession(RESEARCHER, ADMIN);

        if (!session.isInRole(ADMIN) && !AuthUtils.canAccessStudy(studyId)) {
          throw new UnauthorizedException();
        }
    }
    
    @DeleteMapping("/v5/studies/{studyId}/enrollments/{userId}")
    public Enrollment unenroll(...) {
        UserSession session = getAuthenticatedSession(RESEARCHER, ADMIN);

        if (!session.isInRole(ADMIN) && !AuthUtils.canAccessStudy(studyId)) {
          throw new UnauthorizedException();
        }
    }

    @DeleteMapping("/v3/participants/self/enrollments/{userId}")
    public Enrollment unenrollSelf(...) {
        UserSession session = getAuthenticatedSession();
        // set userId to the caller's user Id
    }
}

Another example are org administrators who can list, read, create, and delete administrative accounts in their organizations:

Pros:

Consistent with what we’ve done and thus the least code churn;
Possibly easier for external users to understand our APIs;
Possibly easier to secure down the road with Spring Security (using URL-based security rather than method-based security);

Cons

Honestly I was trying to eliminate keywords like “self” that make more endpoints…that’s more to add to the SDK, more to test, more to document, etc. In the second example, all those APIs are redundant with the participant APIs except for the security differences. Putting all the security within the system is easier;
Some security checks might get tedious. You might still want a DSL class even if doing this work in the controller. The delete user is a good example: