# Multi-Tenant Implementation Audit - Final Report

**Date:** November 29, 2025  
**Auditor:** Automated Audit Process  
**Version:** 1.0

---

## Executive Summary

This audit reviewed the multi-tenant implementation of the LightRAG stack from Web UI through REST API to Storage layer. The implementation uses a **workspace-based isolation model** where `workspace = tenant_id/kb_id`.

### Overall Assessment: ⚠️ FUNCTIONAL WITH CONCERNS

The multi-tenant implementation is **functionally correct** but has several security and architectural concerns that should be addressed before production deployment.

---

## Architecture Overview

```
┌─────────────────────────────────────────────────────────────────┐
│                         Web UI (React)                          │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────────────┐  │
│  │ TenantStore  │  │ KBSelector   │  │ Axios Interceptor    │  │
│  │ (Zustand)    │  │              │  │ X-Tenant-ID Header   │  │
│  └──────────────┘  └──────────────┘  └──────────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
                              │
                    HTTP Headers (X-Tenant-ID, X-KB-ID)
                              │
┌─────────────────────────────────────────────────────────────────┐
│                      REST API (FastAPI)                         │
│  ┌──────────────────┐  ┌────────────────┐  ┌─────────────────┐ │
│  │ get_tenant_      │  │ TenantContext  │  │ TenantRAG       │ │
│  │ context()        │──│ (dataclass)    │──│ Manager         │ │
│  │ dependency       │  │                │  │ (per-tenant RAG)│ │
│  └──────────────────┘  └────────────────┘  └─────────────────┘ │
└─────────────────────────────────────────────────────────────────┘
                              │
                    workspace = tenant_id/kb_id
                              │
┌─────────────────────────────────────────────────────────────────┐
│                     Storage Layer                               │
│  ┌──────────────────────────────────────────────────────────┐  │
│  │ PostgreSQL Tables with workspace column                   │  │
│  │ PRIMARY KEY (workspace, id)                               │  │
│  │                                                           │  │
│  │ Tables: LIGHTRAG_DOC_FULL, LIGHTRAG_DOC_CHUNKS,          │  │
│  │         LIGHTRAG_VDB_*, LIGHTRAG_TENANTS, etc.           │  │
│  └──────────────────────────────────────────────────────────┘  │
│  ┌─────────────────┐  ┌─────────────────┐  ┌────────────────┐  │
│  │ Redis           │  │ Apache AGE      │  │ Vector Store   │  │
│  │ (key prefix)    │  │ (graph per ws)  │  │ (ws filter)    │  │
│  └─────────────────┘  └─────────────────┘  └────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
```

---

## Test Results Summary

### Unit Tests: ✅ ALL PASSED

| Test Suite | Tests | Result |
|------------|-------|--------|
| test_multitenant_e2e.py | 32 | ✅ PASSED |
| test_tenant_security.py | 11 | ✅ PASSED |
| test_multi_tenant_backends.py | 37 | ✅ PASSED |
| test_tenant_storage_phase3.py | 22 | ✅ PASSED |
| **TOTAL** | **102** | **✅ ALL PASSED** |

### Key Verifications
- ✅ Cross-tenant data access prevention
- ✅ Knowledge base isolation within tenants
- ✅ Role-based permission enforcement
- ✅ Composite key uniqueness
- ✅ Redis namespace isolation
- ✅ Vector ID uniqueness per tenant

---

## Security Findings

### Critical Findings

| ID | Severity | Component | Finding |
|----|----------|-----------|---------|
| SEC-001 | 🔴 HIGH | API | `get_tenant_context_optional()` allows global RAG fallback |
| SEC-002 | 🔴 HIGH | API | Admin user bypass in `tenant_service.py` |
| SEC-003 | 🟡 MEDIUM | API | `user_id` parameter optional in RAG manager |
| SEC-004 | 🟡 MEDIUM | Storage | No PostgreSQL Row-Level Security (RLS) |
| SEC-005 | 🟢 LOW | Storage | Tenant context set for logging only |
| SEC-006 | 🟢 LOW | WebUI | localStorage used for token storage |

### SEC-001: Global RAG Fallback (HIGH)

**Location:** `lightrag/api/routers/document_routes.py`, `query_routes.py`

**Issue:** Using `get_tenant_context_optional` allows requests without tenant headers to use global RAG:

```python
async def get_tenant_rag(
    tenant_context: Optional[TenantContext] = Depends(get_tenant_context_optional)
) -> LightRAG:
    if rag_manager and tenant_context:
        return await rag_manager.get_rag_instance(...)
    return rag  # Falls back to global RAG!
```

**Risk:** Data leakage if global RAG contains multi-tenant data.

**Recommendation:** Use `get_tenant_context` (required) for all data endpoints in multi-tenant mode.

### SEC-002: Admin User Bypass (HIGH)

**Location:** `lightrag/services/tenant_service.py`

**Issue:**
```python
if user_id.lower() == "admin":
    return True  # Bypass all access checks
```

**Risk:** Any user with username "admin" can access any tenant's data.

**Recommendation:** Implement proper super-admin role with separate authentication.

### SEC-003: Optional User ID (MEDIUM)

**Location:** `lightrag/tenant_rag_manager.py`

**Issue:** `user_id` parameter is optional, allowing access without authentication check.

**Recommendation:** Deprecate unauthenticated access path.

### SEC-004: No Row-Level Security (MEDIUM)

**Location:** PostgreSQL Tables

**Issue:** Tenant isolation relies entirely on application-level `workspace` filtering. No database-level enforcement.

**Recommendation:** Enable PostgreSQL RLS as defense-in-depth:
```sql
ALTER TABLE LIGHTRAG_DOC_FULL ENABLE ROW LEVEL SECURITY;
CREATE POLICY tenant_isolation ON LIGHTRAG_DOC_FULL
    USING (workspace = current_setting('app.current_workspace'));
```

---

## Architectural Findings

### ARCH-001: Workspace Encoding

**Pattern:** `workspace = "{tenant_id}/{kb_id}"`

**Strengths:**
- Simple, hierarchical namespace
- Clear data ownership
- Compatible with file-based storage

**Concerns:**
- No explicit validation of workspace format
- Potential collision if tenant IDs contain `/`

### ARCH-002: Context Propagation

**Pattern:** Python `ContextVar` for tenant context

```python
tenant_id_var: ContextVar[Optional[str]] = ContextVar("tenant_id")
```

**Current Use:** Set for PostgreSQL session logging, but NOT used for security.

**Recommendation:** Use context variable for RLS enforcement.

### ARCH-003: RAG Instance Caching

**Pattern:** LRU cache keyed by `(tenant_id, kb_id)`

**Strengths:**
- Memory efficient
- Fast subsequent access

**Concerns:**
- Cache size limit may cause thrashing with many tenants
- No cache invalidation on tenant deletion

---

## Web UI Findings

### UI-001: Tenant State Management

**Location:** `lightrag_webui/src/stores/tenant.ts`

**Status:** ✅ Well implemented

- Zustand store with persistence
- Automatic header injection via Axios interceptor
- Console logging for debugging

### UI-002: Document State Clearing

**Location:** `lightrag_webui/src/features/DocumentManager.tsx`

**Recent Fix:** State clearing on tenant/KB change

```typescript
useEffect(() => {
  setCurrentPageDocs([]);
  setDocs(null);
  setStatusCounts({ all: 0 });
  // ...
}, [selectedTenant?.tenant_id, selectedKB?.kb_id]);
```

**Status:** ✅ Fixed (per task log dated 2025-02-25)

### UI-003: Token Storage

**Finding:** Authentication token stored in localStorage

**Risk:** XSS vulnerability could expose tokens

**Recommendation:** Use httpOnly cookies for production

---

## Recommendations

### Priority 1: Critical Security Fixes

1. **Replace `get_tenant_context_optional` with `get_tenant_context`** for all data endpoints
2. **Remove admin bypass** in `tenant_service.py`
3. **Make `user_id` required** in RAG manager

### Priority 2: Defense-in-Depth

4. **Enable PostgreSQL RLS** for all tenant-scoped tables
5. **Validate workspace format** to prevent injection
6. **Add audit logging** for cross-tenant access attempts

### Priority 3: Operational Improvements

7. **Add cache invalidation** on tenant/KB deletion
8. **Implement rate limiting** per tenant
9. **Add metrics/monitoring** for tenant isolation verification

---

## Test Protocol for Manual Verification

### Prerequisites
```bash
# Start test databases
docker compose -f docker-compose.test-db.yml up -d

# Verify containers
docker ps --filter "name=lightrag-audit"
```

### Test Scenarios

#### Scenario 1: Cross-Tenant Data Access Prevention
1. Create Tenant A and KB
2. Upload document to Tenant A
3. Attempt to list documents with Tenant B headers
4. **Expected:** Empty list for Tenant B

#### Scenario 2: Missing Tenant Header
1. Send document list request without X-Tenant-ID header
2. **Expected:** 400 Bad Request OR empty response (not global data)

#### Scenario 3: Query Isolation
1. Insert data into Tenant A KB
2. Query with Tenant B context
3. **Expected:** Query returns no results from Tenant A

### Test Script
```bash
# Run API isolation tests
python docs/action_plan/multitenant-audit/scripts/test_api_isolation.py
```

---

## Conclusion

The LightRAG multi-tenant implementation provides **functional tenant isolation** through:
- Workspace-based table partitioning
- Per-tenant RAG instance management
- Header-based tenant context extraction
- Role-based permission model

However, the implementation has **security gaps** that must be addressed:
1. Optional tenant context fallback to global RAG
2. Admin user bypass in access control
3. No database-level security (RLS)

### Recommended Next Steps

1. 🔴 **Immediate:** Fix SEC-001 and SEC-002 before production
2. 🟡 **Short-term:** Enable PostgreSQL RLS
3. 🟢 **Long-term:** Add comprehensive audit logging and monitoring

---

## Appendices

### A. Files Reviewed

| Layer | Files |
|-------|-------|
| Web UI | `tenant.ts`, `client.ts`, `DocumentManager.tsx` |
| API | `dependencies.py`, `document_routes.py`, `query_routes.py`, `tenant_routes.py` |
| Service | `tenant_service.py`, `tenant_rag_manager.py` |
| Storage | `postgres_impl.py`, `utils_context.py`, `namespace.py` |
| Tests | `test_multitenant_e2e.py`, `test_tenant_security.py`, `test_multi_tenant_backends.py` |

### B. Test Environment

| Component | Version/Config |
|-----------|----------------|
| Python | 3.12.12 |
| PostgreSQL | pgvector/pgvector:pg16 |
| Redis | 7-alpine |
| OS | macOS (arm64) |

### C. Related Documentation

- `docs/0001-multi-tenant-architecture.md`
- `docs/0002-multi-tenant-visual-reference.md`
- `docs/0003-multi-tenant-documentation-index.md`
- `MULTITENANT_IMPLEMENTATION_SUMMARY.md`