Auth is a centralized service that provides authentication and authorization capabilities for Lerian Studio's applications. Built on top of an Identity Provider (IdP), this service offers:

• OAuth2/OIDC-compliant authentication flows
• Token issuance, validation, and refresh capabilities
• User information retrieval according to OIDC standards
• Permission enforcement for resources
• Performance optimization through caching mechanisms

Auth serves as a middleware between Lerian’s applications and the underlying authorization server, providing a unified interface for all authentication and authorization needs while adding caching capabilities to improve performance.

Authentication and Authorization Flow

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Auth implements several key authentication and authorization flows:

Authentication Flow

1. Token Request

   • Client applications request access tokens using either:
     • Password grant (username/password for interactive users)
     • Client credentials grant (for service-to-service authentication)
   • The request is forwarded to the Identity Provider
   • Access token, refresh token, and optional ID token are returned

2. Token Refresh

   • Client applications use refresh tokens to obtain new access tokens
   • The refresh token is validated via the Identity Provider
   • A new access token is issued

3. Token Validation

   • The access tokens are validated on protected resource access
   • The results are cached for performance optimization
   • Token claims are extracted to identify the subject

Authorization Flow

1. Permission Enforcement

   • Client requests access to a resource with an action.
   • The subject ID is extracted from the token.
   • The policy engine determines if the subject has permission.
   • The result is cached for performance.
   • The authorization decision is returned.

2. User Policies Retrieval

   • The client requests all policies for the authenticated user.
   • The policy engine is queried for all permitted resources and actions.
   • Policies are returned as a map of resources to the allowed actions.

User Information Flow

1. User Profile Retrieval
   • The client requests user profile information.
   • The access token is validated.
   • User details are retrieved from the Identity Provider.
   • OIDC-compliant user information is returned.

Logout Flow

1. User Logout
   • Client sends logout request with ID token hint.
   • The tokens are invalidated in the Identity Provider.
   • Cache entries are invalidated.

API Overview

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Auth provides secure identity management and access control for Lerian applications. APIs support:

• Authentication and token lifecycle management.
• Authorization and permission enforcement.
• User information retrieval.

Access to the Auth APIs is secured by strict permission controls. For technical details on endpoints and usage, check the Auth APIs documentation.

Policy Structure

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The policy tables store permissions using the following pattern:

Policy Rule (ptype='p'):

p, <role>, <resource>, <action>, allow, <note>

Example:

p, lerian/identity-editor-role, users, get, allow, lerian/identity-editor-permission

This grants the identity-editor-role permission to perform the GET action on the users resource.

Group Assignment (ptype='g'):

g, <user_id>, <role>

Example:

g, user123, lerian/identity-editor-role  

This assigns the user with ID user123 to the identity-editor-role role.

Data Storage and Caching

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Auth optimizes performance and security by leveraging a structured storage system and caching mechanisms:

• Policy Management: Stores access control policies for users and services.
• Token Introspection Cache: Caches token validation results to reduce redundant checks.
• Permission Cache: Stores authorization decisions to improve response time.
• User Policies Cache: Maintains a map of resources and actions for efficient access control.

Testing & Reliability

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Auth undergoes continuous testing to maintain reliability and security. Tests cover:

• Authentication and token validation flows
• Access control enforcement
• Performance and caching efficiency

Security assessments and monitoring ensure compliance with best practices and evolving security standards.