pgmorbac/docs/DOCUMENTATION.md

pg_morbac Documentation

Complete technical documentation for the Multi-OrBAC PostgreSQL extension.

Table of Contents

• Architecture
• Schema Reference
• Core Concepts
• Advanced Features
• API Reference
• Integration Guides
• Performance
• Security Model

Architecture

Design Principles

pg_morbac is built on these principles:

1. Pure PostgreSQL: No external dependencies (except pgcrypto)
2. Schema Isolation: All objects in morbac schema
3. Default Deny: No permission = access denied
4. Prohibition Precedence: Prohibitions checked first, always override permissions
5. Organization-Centric: All policies scoped to organizations
6. Multi-Tenant Native: Users and resources can span organizations

Authorization Flow

flowchart TD
    A[Authorization Request] --> B[Get Comprehensive Roles]
    B --> C[Direct Assignments]
    B --> D[Delegations]
    B --> E[Derived Roles]
    B --> F[Role Hierarchy]
    C --> G[Filter Negative Assignments]
    D --> G
    E --> G
    F --> G
    G --> H{Check Prohibitions}
    H -->|Found| I[DENY]
    H -->|Not Found| J{Check Permissions}
    J -->|Found| K[ALLOW]
    J -->|Not Found| L[DENY - Default]

Performance Optimizations

Prohibition-first checking: Prohibitions are checked before permissions for early exit on denial.

Indexed foreign keys: All foreign key relationships have indexes for fast joins.

Composite indexes: Optimized indexes for common query patterns (org_id, role_id, activity, view).

STABLE functions: RLS functions are marked STABLE for transaction-level caching.

Recursive CTEs: Efficient hierarchy traversal using PostgreSQL's recursive common table expressions.

Schema Reference

Entity Relationship Diagram

erDiagram
    orgs ||--o{ orgs : "parent_id"
    orgs ||--o{ roles : "has"
    orgs ||--o{ user_roles : "contains"
    orgs ||--o{ rules : "defines"

    roles ||--o{ user_roles : "assigned_to"
    roles ||--o{ role_hierarchy : "senior"
    roles ||--o{ role_hierarchy : "junior"
    roles ||--o{ rules : "applies_to"

    activities ||--o{ rules : "action"
    activities ||--o{ activity_hierarchy : "parent"
    activities ||--o{ activity_hierarchy : "child"

    views ||--o{ rules : "target"
    views ||--o{ view_hierarchy : "parent"
    views ||--o{ view_hierarchy : "child"

    contexts ||--o{ rules : "condition"

    roles ||--o{ delegations : "delegated"
    roles ||--o{ negative_role_assignments : "prohibited"
    roles ||--o{ sod_conflicts : "conflicts_with"
    roles ||--o{ derived_roles : "computed"

Core Tables

morbac.orgs: Organizations with hierarchy support (parent_id self-reference). Unique name required. Supports metadata as JSONB.

morbac.roles: Roles scoped to organizations. Unique (org_id, name) constraint ensures role names are unique within each org.

morbac.role_hierarchy: Role inheritance via (senior_role_id, junior_role_id). Senior roles inherit all junior permissions. Supports transitive closure.

morbac.user_roles: Direct user-to-role assignments. Primary key on (user_id, role_id, org_id). Note: user_id is external (application manages users).

morbac.activities: Abstract actions (global scope). Text primary key. Examples: read, write, delete, approve.

morbac.activity_hierarchy: Activity inheritance via (parent_activity, child_activity). Permission to parent grants child activities.

morbac.views: Abstract object categories (global scope). Text primary key. Examples: documents, reports, financial_data.

morbac.view_hierarchy: View inheritance via (parent_view, child_view). Access to parent grants child views.

morbac.contexts: Contextual conditions as callable predicates. Column evaluator (REGPROC) references a function returning BOOLEAN (preferably STABLE). Built-in context always returns true.

morbac.rules: Core policy rules linking org, role, activity, view, context, and modality. Indexed on (org_id, role_id, activity, view, modality) for fast lookups.

morbac.policy: Policy DSL using names instead of UUIDs. Insert here, then call compile_policy() to generate rules.

Advanced Feature Tables

morbac.delegations

Temporal role delegation with time bounds.

Key columns:

• delegator_user_id: User granting the role
• delegate_user_id: User receiving the role
• role_id, org_id: Role being delegated
• valid_from, valid_until: Time window (NULL = indefinite)

Behavior: Automatically included in get_comprehensive_roles() when active.

morbac.negative_role_assignments

Explicit role prohibitions with highest precedence.

Key columns:

• user_id, role_id, org_id: Assignment to prohibit
• reason: Explanation for prohibition

Behavior: Overrides direct assignments, delegations, and derived roles.

morbac.sod_conflicts

Separation of Duty constraints enforce mutually exclusive roles.

Key columns:

• role1_id, role2_id: Conflicting role pair
• org_id: Organization scope
• description: Explanation of conflict

Behavior: Prevents users from holding both roles simultaneously. Validated via check_sod_violation() before role assignment.

morbac.role_cardinality

Constrains the number of users per role.

Key columns:

• role_id, org_id: Role to constrain
• min_users: Minimum required users (default 0)
• max_users: Maximum allowed users (NULL = unlimited)

Behavior: Validated via check_cardinality_violation() before role assignment.

morbac.derived_roles

Dynamically computed roles via custom functions.

Key columns:

• role_id, org_id: Role to compute
• evaluator: Function returning TABLE(user_id UUID, org_id UUID)
• description: Explanation of computation logic

Behavior: Function is called at runtime to determine role membership. Included in get_comprehensive_roles().

morbac.cross_org_rules

Inter-organizational access policies.

Key columns:

• source_org_id: Organization where role is held
• target_org_id: Organization where access is granted
• role_id, activity, view: Policy specification
• modality: Permission or prohibition

Behavior: Allows roles in source organization to access resources in target organization.

morbac.admin_rules

Administration meta-policies for delegated management.

Key columns:

• org_id, role_id: Role receiving admin capabilities
• can_manage_policies: Can create/modify policies
• can_manage_roles: Can create/modify roles
• can_manage_users: Can assign/revoke user roles

Behavior: Enables organization-scoped administrators without database superuser privileges.

Core Concepts

Deontic Modalities

Multi-OrBAC implements four modalities:

1. Permission: Allows action (if no prohibition)
2. Prohibition: Denies action (always wins)
3. Obligation: Must be done (informational only)
4. Recommendation: Should be done (informational only)

Only permissions and prohibitions affect is_allowed() decisions.

Context Evaluation

Contexts are boolean predicates that determine if a rule applies:

-- Context function signature
CREATE OR REPLACE FUNCTION morbac.my_context()
RETURNS BOOLEAN
LANGUAGE plpgsql
STABLE  -- Important for RLS performance
AS $$
BEGIN
    RETURN <condition>;
END;
$$;

-- Register context
INSERT INTO morbac.contexts (name, evaluator) VALUES
    ('my_context', 'morbac.my_context'::regproc);

Context functions should:

• Use STABLE (not VOLATILE) for RLS compatibility
• Keep logic simple and fast
• Avoid external dependencies
• Consider caching if computation is expensive

Policy DSL

Simplified policy declaration:

-- Insert policies using names
INSERT INTO morbac.policy (org_name, role_name, activity, view, modality) VALUES
    ('Acme Corp', 'manager', 'approve', 'requests', 'permission');

-- Compile (idempotent)
SELECT * FROM morbac.compile_policy();

Compiler behavior:

• Creates missing activities/views
• Resolves names to UUIDs
• Creates entries in morbac.rules
• Reports errors for missing orgs/roles/contexts
• Safe to run multiple times

Advanced Features

Hierarchies

Organizations, roles, activities, and views all support hierarchical relationships with transitive closure.

-- Organization hierarchy (via parent_id)
INSERT INTO morbac.orgs (name, parent_id) VALUES ('EMEA', parent_org_id);
SELECT * FROM morbac.get_org_ancestors(org_id);
SELECT * FROM morbac.get_org_descendants(org_id);

-- Role hierarchy (senior inherits from junior)
INSERT INTO morbac.role_hierarchy (senior_role_id, junior_role_id)
VALUES (manager_role_id, employee_role_id);
SELECT * FROM morbac.get_inherited_roles(role_id);

-- Activity hierarchy (parent includes children)
INSERT INTO morbac.activity_hierarchy (parent_activity, child_activity)
VALUES ('write', 'create'), ('write', 'update');
SELECT * FROM morbac.get_effective_activities('write');

-- View hierarchy (parent includes children)
INSERT INTO morbac.view_hierarchy (parent_view, child_view)
VALUES ('documents', 'invoices'), ('documents', 'contracts');
SELECT * FROM morbac.get_effective_views('documents');

Example hierarchy diagram:

graph TD
    A[Director] -->|inherits from| B[Manager]
    B -->|inherits from| C[Employee]
    A -.->|transitive| C

Delegation

Temporary role delegation with time bounds:

INSERT INTO morbac.delegations (
    delegator_user_id, delegate_user_id, role_id, org_id,
    valid_from, valid_until
) VALUES (
    alice_uuid, bob_uuid, approver_role_id, org_id,
    NOW(), NOW() + INTERVAL '7 days'
);

Automatically included in get_comprehensive_roles() when active. Set valid_until to NULL for indefinite delegation.

Negative Role Assignments

Explicit prohibitions with highest precedence:

INSERT INTO morbac.negative_role_assignments (user_id, role_id, org_id, reason)
VALUES (user_uuid, admin_role_id, org_id, 'Security audit requirement');

Separation of Duty

Prevents users from holding conflicting roles that could enable fraud or abuse.

Example: Financial Controls

In an accounting system, the same person should not both create and approve invoices:

-- Create roles
INSERT INTO morbac.roles (org_id, name) VALUES
    (org_id, 'invoice_creator'),
    (org_id, 'invoice_approver');

-- Define conflict
INSERT INTO morbac.sod_conflicts (role1_id, role2_id, org_id, description)
VALUES (creator_role_id, approver_role_id, org_id, 'Financial controls: prevent self-approval');

-- Check before assignment
SELECT morbac.check_sod_violation(alice_uuid, org_id);
-- Returns: empty array if valid, or ['invoice_creator', 'invoice_approver'] if conflict exists

If Alice already has the invoice_creator role, attempting to assign invoice_approver will violate the constraint.

Cardinality Constraints

Enforce minimum and maximum users per role:

-- Require 1-3 administrators
INSERT INTO morbac.role_cardinality (role_id, org_id, min_users, max_users)
VALUES (admin_role_id, org_id, 1, 3);

-- Validate before assignment
SELECT morbac.check_cardinality_violation(admin_role_id, org_id);
-- Returns: error message if constraint violated, NULL if valid

Dynamically computed roles via custom functions:

CREATE OR REPLACE FUNCTION morbac.eval_project_leads()
RETURNS TABLE(user_id UUID, org_id UUID)
LANGUAGE sql STABLE AS $$
    SELECT user_id, org_id FROM app.projects WHERE lead_user_id IS NOT NULL;
$$;

INSERT INTO morbac.derived_roles (role_id, org_id, evaluator)
VALUES (project_lead_role_id, org_id, 'morbac.eval_project_leads'::regproc);

Cross-Organizational Rules

Inter-organizational access policies:

INSERT INTO morbac.cross_org_rules (
    source_org_id, target_org_id, role_id, activity, view, modality
) VALUES (
    global_org_id, subsidiary_org_id, auditor_role_id,
    'read', 'financial_reports', 'permission'
);

Administration Rules

Meta-policies for policy management:

INSERT INTO morbac.admin_rules (org_id, role_id, can_manage_policies)
VALUES (org_id, sec_admin_role_id, true);

SELECT morbac.is_admin_allowed(user_uuid, org_id, 'manage_policies');

Temporal Constraints

Rules and cross-organizational rules support optional temporal validity periods. Rules are only active within their specified time window.

Adding temporal constraints to rules:

-- Rule active only in 2024
INSERT INTO morbac.rules (org_id, role_id, activity, view, context_id, modality, valid_from, valid_until)
VALUES (org_id, contractor_role_id, 'read', 'projects', ctx_id, 'permission',
        '2024-01-01 00:00:00+00', '2024-12-31 23:59:59+00');

-- Rule active starting from a specific date (no end date)
INSERT INTO morbac.rules (org_id, role_id, activity, view, context_id, modality, valid_from)
VALUES (org_id, employee_role_id, 'read', 'handbook', ctx_id, 'permission',
        '2024-06-01 00:00:00+00');

-- Rule expires at a specific date
INSERT INTO morbac.rules (org_id, role_id, activity, view, context_id, modality, valid_until)
VALUES (org_id, temp_role_id, 'write', 'reports', ctx_id, 'permission',
        '2024-12-31 23:59:59+00');

Temporal constraints on cross-org rules:

INSERT INTO morbac.cross_org_rules (
    source_org_id, target_org_id, role_id, activity, view, modality,
    valid_from, valid_until
) VALUES (
    parent_org_id, subsidiary_org_id, auditor_role_id,
    'read', 'financial_data', 'permission',
    '2024-01-01 00:00:00+00', '2024-03-31 23:59:59+00'
);

Checking rule validity manually:

SELECT morbac.is_rule_valid(valid_from, valid_until);
-- Returns: TRUE if current time is within bounds (or no constraints set)
--          FALSE if outside validity period

Behavior:

• Both valid_from and valid_until are optional (can be NULL)
• If both are NULL, rule is always active
• If only valid_from is set, rule is active from that time onwards
• If only valid_until is set, rule is active until that time
• If both are set, rule is active only during that window
• is_allowed() automatically checks temporal validity for all rules
• Expired rules are effectively inactive but remain in database for audit purposes

Audit Logging

Comprehensive audit trail for security-critical operations. The audit system tracks all INSERT, UPDATE, and DELETE operations on specified tables.

Audit log table structure:

morbac.audit_log (
    id              BIGSERIAL PRIMARY KEY,
    timestamp       TIMESTAMPTZ,      -- When change occurred
    user_id         UUID,             -- User making change (if applicable)
    org_id          UUID,             -- Organization context
    table_name      TEXT,             -- Table being modified
    operation       TEXT,             -- INSERT, UPDATE, DELETE
    record_id       UUID,             -- ID of affected record
    old_data        JSONB,            -- Record state before change (UPDATE/DELETE)
    new_data        JSONB,            -- Record state after change (INSERT/UPDATE)
    changed_fields  TEXT[],           -- List of modified columns (UPDATE)
    session_user    TEXT,             -- PostgreSQL session user
    client_addr     INET,             -- Client IP address
    application_name TEXT,            -- Application name from connection
    metadata        JSONB             -- Additional custom metadata
)

Enabling audit logging:

-- Enable auditing on user_roles table
SELECT morbac.enable_audit('user_roles');

-- Enable auditing on multiple tables
SELECT morbac.enable_audit('rules');
SELECT morbac.enable_audit('delegations');
SELECT morbac.enable_audit('admin_rules');

Disabling audit logging:

SELECT morbac.disable_audit('user_roles');

Querying audit log:

-- Recent changes to user_roles
SELECT
    timestamp,
    operation,
    session_user,
    old_data->>'role_id' AS old_role,
    new_data->>'role_id' AS new_role
FROM morbac.audit_log
WHERE table_name = 'user_roles'
ORDER BY timestamp DESC
LIMIT 20;

-- All changes by specific user
SELECT * FROM morbac.audit_log
WHERE user_id = '123e4567-e89b-12d3-a456-426614174000'
ORDER BY timestamp DESC;

-- Changes to specific record
SELECT * FROM morbac.audit_log
WHERE table_name = 'rules' AND record_id = rule_uuid
ORDER BY timestamp;

-- Detect field-level changes
SELECT
    timestamp,
    record_id,
    changed_fields,
    old_data,
    new_data
FROM morbac.audit_log
WHERE table_name = 'rules'
  AND operation = 'UPDATE'
  AND 'modality' = ANY(changed_fields);

Best practices:

• Enable auditing on security-critical tables: user_roles, rules, delegations, admin_rules, sod_conflicts
• Create indexes on frequently queried columns: CREATE INDEX ON morbac.audit_log(table_name, timestamp DESC)
• Implement retention policies to archive old audit logs
• Use JSONB operators to query old_data and new_data efficiently
• Consider partitioning audit_log by timestamp for large installations

API Reference

Authorization Functions

is_allowed(user_id, org_id, activity, view): Main authorization decision. Returns BOOLEAN. Checks prohibitions first, then permissions, defaults to deny.

SELECT morbac.is_allowed(user_uuid, org_uuid, 'read', 'documents');

get_comprehensive_roles(user_id, org_id): Returns all roles for user (direct, delegated, derived, hierarchy, minus negative assignments).

get_effective_roles(user_id, org_id): Alias for get_comprehensive_roles().

Hierarchy Functions

get_org_ancestors(org_id): Returns all parent organizations with depth.

get_org_descendants(org_id): Returns all child organizations with depth.

get_inherited_roles(role_id): Returns all junior roles (transitive).

get_effective_activities(activity): Returns activity plus all child activities.

get_effective_views(view): Returns view plus all child views.

Validation Functions

check_sod_violation(user_id, org_id): Returns empty array if valid, or array of conflicting role name pairs if violations exist.

check_cardinality_violation(role_id, org_id): Returns error message if constraint violated, NULL if valid.

Administration Functions

is_admin_allowed(user_id, org_id, capability): Check administrative permissions. Capabilities: manage_policies, manage_roles, manage_users.

eval_derived_role(user_id, org_id, derived_role_id): Evaluate if user has derived role.

Context Functions

eval_context(context_id): Evaluate a context predicate.

Policy DSL Functions

compile_policy(): Compile policy DSL into rules. Returns TABLE with success status and messages. Idempotent.

RLS Helper Functions

current_user_id(): Get user ID from request.header.x-user-id (PostgREST) or current_setting('morbac.user_id').

current_org_id(): Get org ID from request.header.x-org-id (PostgREST) or current_setting('morbac.org_id').

rls_check(activity, view): Authorization check for RLS policies using current user/org context.

CREATE POLICY my_policy ON app.table
FOR SELECT USING (morbac.rls_check('read', 'documents'));

Informational Functions

pending_obligations(user_id, org_id): Returns obligations for user (informational only).

pending_recommendations(user_id, org_id): Returns recommendations for user (informational only).

user_has_role(user_id, org_id, role_name): Check if user has specific role by name.

morbac.user_has_role(
    p_user_id UUID,
    p_org_id UUID,
    p_role_name TEXT
) RETURNS BOOLEAN

Integration Guides

PostgREST Integration

Configure PostgREST to pass user/org context via headers:

# Nginx config
proxy_set_header X-User-Id $user_id;
proxy_set_header X-Org-Id $org_id;

Enable RLS and grant permissions:

ALTER TABLE app.documents ENABLE ROW LEVEL SECURITY;

GRANT USAGE ON SCHEMA morbac TO postgrest_role;
GRANT SELECT ON ALL TABLES IN SCHEMA morbac TO postgrest_role;
GRANT EXECUTE ON ALL FUNCTIONS IN SCHEMA morbac TO postgrest_role;

Create RLS policies:

CREATE POLICY document_read ON app.documents
FOR SELECT
USING (morbac.rls_check('read', 'documents'));

CREATE POLICY document_write ON app.documents
FOR INSERT
WITH CHECK (morbac.rls_check('write', 'documents'));

Alternative method using session variables:

SET morbac.user_id = '123e4567-e89b-12d3-a456-426614174000';
SET morbac.org_id = '987fcdeb-51a2-43d7-9c6e-5a8b7c9d0e1f';

Application Integration

Python example:

import psycopg2
conn = psycopg2.connect("dbname=mydb")
cursor = conn.cursor()
cursor.execute("SET morbac.user_id = %s", [user_id])
cursor.execute("SET morbac.org_id = %s", [org_id])
cursor.execute("SELECT * FROM app.documents")  # RLS enforced

Node.js example:

const client = await pool.connect();
await client.query('SET morbac.user_id = $1', [userId]);
await client.query('SET morbac.org_id = $1', [orgId]);
const res = await client.query('SELECT * FROM app.documents');

Multi-Organization Resources

Resources can belong to multiple organizations using a junction table:

-- Application defines document-org relationships
-- morbac.rls_check() enforces access rules
CREATE POLICY doc_access ON app.documents FOR SELECT USING (
    EXISTS (
        SELECT 1 FROM app.document_orgs
        WHERE document_id = app.documents.id
          AND org_id = morbac.current_org_id()
    )
    AND morbac.rls_check('read', 'documents')
);

Performance

Optimization Strategies

Prohibition-first checking provides early exit on denial for both security and performance.

For large hierarchies, use materialized views:

CREATE MATERIALIZED VIEW morbac.mv_role_closure AS
SELECT senior_role_id, junior_role_id FROM ...;
CREATE INDEX ON morbac.mv_role_closure(senior_role_id);
REFRESH MATERIALIZED VIEW morbac.mv_role_closure;

Context optimization:

• Use STABLE functions (not VOLATILE) for RLS caching
• Avoid expensive computations or external calls
• Keep context logic simple

All foreign keys are indexed. Critical composite indexes exist on (user_id, org_id) and (org_id, role_id, activity, view, modality).

Benchmarking

Example query performance (1M rules, 10K users, 100 orgs):

-- Simple authorization check
EXPLAIN ANALYZE
SELECT morbac.is_allowed(user_id, org_id, 'read', 'documents');
-- Typical: 5-15ms

-- With hierarchies (3 levels)
EXPLAIN ANALYZE
SELECT morbac.is_allowed(user_id, org_id, 'read', 'documents');
-- Typical: 10-30ms

-- RLS query (1M rows)
EXPLAIN ANALYZE
SELECT * FROM app.documents WHERE morbac.rls_check('read', 'documents');
-- Depends on selectivity, uses indexes

Security Model

Threat Model

Protected against:

• Unauthorized access (default deny)
• Privilege escalation (prohibition precedence)
• SQL injection (parameterized queries)
• Org boundary violations (explicit cross-org rules)

Not protected against:

• Malicious context functions (trusted code)
• Database user privilege escalation (PostgreSQL security model)
• Time-of-check/time-of-use races (transaction-based consistency only)

Security Best Practices

Context Function Security

-- BAD: Leaks information
CREATE FUNCTION morbac.bad_context()
RETURNS BOOLEAN VOLATILE AS $$
    SELECT EXISTS(SELECT 1 FROM sensitive_table);
$$;

-- GOOD: Self-contained, stable
CREATE FUNCTION morbac.good_context()
RETURNS BOOLEAN STABLE AS $$
    SELECT EXTRACT(HOUR FROM CURRENT_TIME) BETWEEN 9 AND 17;
$$;

User ID Validation

-- Validate user exists before authorization
SELECT morbac.is_allowed(
    user_id,  -- Must be from authenticated session
    org_id,
    activity,
    view
);

Org Context Validation

-- Verify user belongs to org
SELECT EXISTS(
    SELECT 1 FROM morbac.user_roles
    WHERE user_id = ? AND org_id = ?
);

Comparison: Multi-OrBAC vs Traditional RBAC

Aspect	Traditional RBAC	Multi-OrBAC (pg_morbac)
Multi-tenancy	Single tenant or complex workarounds	Native multi-organization
Prohibition	No standard support	First-class, always wins
Context	Static permissions	Dynamic, condition-based
Hierarchy	Basic (roles only)	Full (orgs, roles, activities, views)
Delegation	Manual implementation	Native temporal delegation
SoD	Application logic	Database-enforced constraints
Cross-tenant	Not supported	Native cross-org rules
Audit	Application layer	Meta-policies (admin rules)

---

Additional Resources

• Multi-OrBAC Research Paper
• test_morbac.sql: Comprehensive examples
• CHANGELOG.md: Version history
• CONTRIBUTING.md: Contribution guidelines
• SECURITY.md: Security policy