As web applications increasingly adopt a microservices architecture, managing authorization, and access control becomes more complex. Developers must verify user identities and enforce precise controls over resources and actions. This is where identity and access management (IAM) becomes essential.

In a recent technical presentation, the Broadleaf team shared how their platform addresses these IAM challenges through OAuth 2.0 and a robust policy enforcement system. Here are the key insights from the session.

Understanding OAuth 2.0 for Delegated Access

OAuth 2.0, an open standard, is at the core of Broadleaf's authorization model. It allows applications to access user data on their behalf without requiring users to share login credentials. This process involves a delegation flow, where users grant applications specific permissions to access resources.

OAuth 2.0 Flow in Broadleaf

1. Request Access: A client application (e.g., a React-based storefront) requests access to a resource from a resource server (e.g., a microservice).
2. Redirect for Consent: Since the client lacks authorization, the user is redirected to the authorization server (part of Broadleaf’s authentication service) to obtain consent.
3. Grant Permission: After the user authenticates and grants permission, the authorization server issues an authorization grant.
4. Obtain Access Token: The client exchanges the authorization grant for an access token, which it uses to access the resource server.

The flow enables secure delegation by ensuring client applications never directly handle user credentials. This separation is essential for security and scalability in microservices architectures.

Grant Types in Broadleaf

• Authorization Code Grant: Used for user delegation, where a client application accesses resources on behalf of an authenticated user. The user consents and the client receives an authorization code to exchange for an access token.
• Client Credentials Grant: Used for server-to-server communication, where one microservice accesses resources on its behalf using a client ID and secret.

By decoupling authentication from authorization, OAuth 2.0 enables Broadleaf to maintain a consistent authorization model across the platform while integrating with different authentication services as needed. This flexibility is vital for adapting to evolving application needs.

Anatomy of an Access Token

Access tokens are central to authorization. Broadleaf’s tokens are JSON Web Tokens (JWTs) that are digitally signed to ensure integrity. Key claims within the token include:

• Identity Claims: Details about the authenticated user (e.g., name, ID).
• User Context Claims: Information about the user’s context, such as tenant and application access.
• Authorities Claims: A list of permissions (e.g., update_product) granted to the user.

Custom Claims

Broadleaf extends standard OAuth 2.0 tokens with custom claims, such as admin status and customer ID, to enhance authorization decisions. These customizations allow for granular control tailored to the platform’s unique needs.

Token Lifespan

Access tokens are intentionally short-lived to mitigate risks if a token is compromised. This ensures that even if a malicious actor obtains a token, their window of opportunity is limited.

Enforcing Authorization with Broadleaf Policies

Broadleaf’s policy enforcement system extends token-based authorization with fine-grained controls using the @Policy annotation. This annotation is applied to API endpoints and repository methods, allowing developers to specify authorization requirements, such as:

• Permission Validation: Defines required permissions and their matching strategies.
• Ownership Validation: Ensures users can only access or modify resources they own.
• Mutability Validation: Checks permissions for modifying entities based on trackable behaviors (e.g., tenant, catalog).

Policy Merging

Broadleaf’s system merges policies along the call stack, allowing policy definitions at higher levels (such as endpoints) to automatically apply to lower levels (such as repositories) within a single request. For example, a policy annotation can be defined on a method in the endpoint layer, while another policy annotation is set on a repository method that is called during request processing. When the request reaches the repository method, the policy annotation there will automatically inherit all of the information defined at the endpoint layer. This eliminates the need to duplicate policy declarations at multiple levels and improves reusability within a service.

Policy Overrides

Broadleaf supports policy overrides, allowing clients to customize or replace the default @Policy configuration for specific components within the framework. This mechanism enables the introduction of policy enforcement to components that do not have built-in policy configuration, including areas within the Broadleaf framework itself or third-party components such as those provided by Spring or other libraries. By enabling policy enforcement at both granular and overarching levels, Broadleaf ensures comprehensive security coverage across its microservices without sacrificing development efficiency.

Managing Permissions and Roles

Permissions in Broadleaf follow the format <operation>_<permission_root>, where operations include create, read, update, delete, or all. Permissions are organized into roles and pre-defined sets of permissions assigned to users. For instance:

• A Merchandiser role might include read_product, update_product, and create_promotion.
• A Customer Service Agent role might include permissions to manage customer information and orders.

Administrators can configure roles and permissions via the Broadleaf admin interface. A role-based access control (RBAC) model simplifies access control.

Role-Based Access Control (RBAC)

RBAC simplifies permission management by associating users with roles instead of configuring individual permissions. This approach reduces administrative overhead and ensures consistent access control policies across the platform.

Dynamic Role Updates

Broadleaf’s system allows for dynamic updates to roles and permissions, enabling administrators to respond quickly to changing business requirements. For example, a new product line might require additional permissions for merchandisers, which can be configured and applied without system downtime.

Securing New Services and Going to Production

As new microservices are added to the Broadleaf ecosystem, securing them is straightforward. By including the broadleaf-oauth2-resource-security library, developers can:

• Verify access tokens.
• Leverage policy enforcement features without implementing IAM from scratch.

Production Considerations

To ensure a secure production environment, Broadleaf emphasizes:

• Generate Signing Keys: Replace default JWT signing keys with new ones to enhance security.
• Leverage Advanced Features: Utilize features like impersonation (for customer support) and refresh tokens (for long-lived sessions).
• Monitor Security Logs: Regularly review logs for unusual access patterns or potential breaches.

Impersonation

Broadleaf’s impersonation feature allows customer support representatives to access the store on their customers' behalf. This functionality improves customer service while maintaining secure access boundaries.

Scalable Security

Broadleaf’s IAM system's modular design ensures that new services automatically inherit security best practices. Developers can focus on building features while relying on the platform to handle authorization complexities.

Conclusion

Broadleaf’s security model, powered by OAuth 2.0 and a robust policy enforcement system, addresses the complexities of managing authorization in a microservices architecture. Broadleaf empowers developers to build secure, scalable, and maintainable web applications by combining flexible access tokens, customizable policies, and role-based permissions.

As the microservices landscape continues to evolve, Broadleaf’s security model ensures that developers can confidently meet modern challenges while delivering exceptional user experiences.