ColaFlow/docs/stories/sprint_5/story_5_7.md

story_id, sprint_id, phase, status, priority, story_points, assignee, estimated_days, created_date, dependencies

story_id	sprint_id	phase	status	priority	story_points	assignee	estimated_days	created_date	dependencies
story_5_7	sprint_5	Phase 2 - Resources	not_started	P0	5	backend	2	2025-11-06	story_5_5 story_5_2

Story 5.7: Multi-Tenant Isolation Verification

Phase: Phase 2 - Resources (Week 3-4) Priority: P0 CRITICAL Estimated Effort: 5 Story Points (2 days)

User Story

As a Security Engineer I want 100% multi-tenant data isolation for all MCP operations So that AI agents cannot access data from other tenants

Business Value

Multi-tenant security is CRITICAL for M2. A single data leak could:

• Violate customer trust
• Cause legal liability (GDPR, SOC2)
• Damage brand reputation
• Block enterprise adoption

This Story ensures zero cross-tenant data access.

Acceptance Criteria

AC1: TenantContext Service

• Extract TenantId from API Key
• Set CurrentTenantId in request context
• Accessible to all MCP operations

AC2: Global Query Filters

• EF Core Global Query Filters applied to all entities
• All queries automatically filtered by TenantId
• Cannot be disabled by accident

AC3: Repository Level Isolation

• All repositories enforce TenantId filter
• No queries bypass tenant check
• Aggregate roots include TenantId property

AC4: Integration Tests

• Create 2 test tenants (Tenant A, Tenant B)
• Create test data in each tenant
• Test 1: Tenant A API Key cannot read Tenant B projects
• Test 2: Tenant A API Key cannot read Tenant B issues
• Test 3: Tenant A API Key cannot read Tenant B users
• Test 4: Direct ID access fails for other tenant's data
• Test 5: Search queries never return cross-tenant results
• All tests must pass (100% isolation)

AC5: Security Audit

• Code review by security team
• Static analysis (no raw SQL without TenantId)
• Verify all API endpoints enforce tenant filter

Technical Design

TenantContext Service

public interface ITenantContext
{
    Guid CurrentTenantId { get; }
}

public class McpTenantContext : ITenantContext
{
    private readonly IHttpContextAccessor _httpContextAccessor;

    public Guid CurrentTenantId
    {
        get
        {
            var tenantId = _httpContextAccessor.HttpContext?.Items["TenantId"];
            if (tenantId == null)
                throw new McpUnauthorizedException("Tenant context not set");

            return (Guid)tenantId;
        }
    }
}

Global Query Filters

public class ColaFlowDbContext : DbContext
{
    private readonly ITenantContext _tenantContext;

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        // Apply tenant filter to all tenant-scoped entities
        modelBuilder.Entity<Project>()
            .HasQueryFilter(p => p.TenantId == _tenantContext.CurrentTenantId);

        modelBuilder.Entity<Epic>()
            .HasQueryFilter(e => e.TenantId == _tenantContext.CurrentTenantId);

        modelBuilder.Entity<Story>()
            .HasQueryFilter(s => s.TenantId == _tenantContext.CurrentTenantId);

        modelBuilder.Entity<WorkTask>()
            .HasQueryFilter(t => t.TenantId == _tenantContext.CurrentTenantId);

        modelBuilder.Entity<Sprint>()
            .HasQueryFilter(s => s.TenantId == _tenantContext.CurrentTenantId);

        modelBuilder.Entity<User>()
            .HasQueryFilter(u => u.TenantId == _tenantContext.CurrentTenantId);
    }
}

Integration Test Example

[Fact]
public async Task TenantA_CannotReadTenantB_Projects()
{
    // Arrange
    var tenantA = await CreateTestTenant("Tenant A");
    var tenantB = await CreateTestTenant("Tenant B");

    var apiKeyA = await CreateApiKey(tenantA.Id, "API Key A");
    var projectB = await CreateProject(tenantB.Id, "Project B");

    // Act - Tenant A tries to access Tenant B's project
    var result = await CallMcpResource(
        apiKeyA,
        $"colaflow://projects.get/{projectB.Id}");

    // Assert
    Assert.Equal(404, result.StatusCode); // NOT 403 (don't leak existence)
    Assert.Null(result.Data);
}

[Fact]
public async Task IssuesSearch_NeverReturnsCrossTenant_Results()
{
    // Arrange
    var tenantA = await CreateTestTenant("Tenant A");
    var tenantB = await CreateTestTenant("Tenant B");

    await CreateIssue(tenantA.Id, "Issue A");
    await CreateIssue(tenantB.Id, "Issue B");

    var apiKeyA = await CreateApiKey(tenantA.Id, "API Key A");

    // Act - Tenant A searches all issues
    var result = await CallMcpResource(
        apiKeyA,
        "colaflow://issues.search");

    // Assert
    var issues = result.Data["issues"];
    Assert.Single(issues); // Only Tenant A's issue
    Assert.Equal("Issue A", issues[0]["title"]);
}

Tasks

Task 1: TenantContext Service (2 hours)

• Create ITenantContext interface
• Implement McpTenantContext (extract from HttpContext)
• Register in DI container
• Update API Key middleware to set TenantId

Files to Create:

• ColaFlow.Modules.Mcp/Services/McpTenantContext.cs

Task 2: Global Query Filters (3 hours)

• Add TenantId to all aggregate roots (if missing)
• Configure Global Query Filters in DbContext
• Test filters apply automatically
• Verify cannot be disabled

Files to Modify:

• ColaFlow.Infrastructure/Data/ColaFlowDbContext.cs

Task 3: Repository Validation (2 hours)

• Audit all repository methods
• Ensure all queries include TenantId
• Add TenantId to method signatures if needed

Task 4: Integration Tests - Cross-Tenant Access (6 hours)

• Create multi-tenant test infrastructure
• Test 1: Projects cross-tenant access
• Test 2: Issues cross-tenant access
• Test 3: Users cross-tenant access
• Test 4: Direct ID access (404, not 403)
• Test 5: Search never returns cross-tenant results

Files to Create:

• ColaFlow.Modules.Mcp.Tests/Integration/MultiTenantIsolationTests.cs

Task 5: Security Audit (3 hours)

• Code review by security team
• Static analysis (grep for raw SQL)
• Verify all API endpoints use TenantContext
• Document security architecture

Files to Create:

• docs/security/multi-tenant-isolation-audit.md

Testing Strategy

Integration Tests (Critical)

• 2 test tenants with separate data
• 10+ test scenarios covering all Resources
• 100% isolation verified
• Tests must fail if isolation broken

Security Audit Checklist

• All entities have TenantId property
• Global Query Filters configured
• No raw SQL without TenantId
• All API endpoints use TenantContext
• Return 404 (not 403) for cross-tenant access
• Audit logs include TenantId

Dependencies

Prerequisites:

• Story 5.2 (API Key Management) - API Key linked to Tenant
• Story 5.5 (Core Resources) - Resources to test

Critical Path: BLOCKS M2 production deployment

Risks & Mitigation

Risk	Impact	Probability	Mitigation
Tenant leak vulnerability	CRITICAL	Low	100% test coverage, code review
Global filter bypass	HIGH	Low	EF Core best practices, testing
Performance impact	Medium	Low	Indexed TenantId columns

Definition of Done

• TenantContext service working
• Global Query Filters applied
• ALL integration tests passing (100%)
• Security audit complete (no findings)
• Code reviewed by security team
• Documentation updated

Notes

Why This Story Matters

• CRITICAL SECURITY: Single most important security Story in M2
• Compliance: Required for GDPR, SOC2, enterprise customers
• Trust: Multi-tenant leaks destroy customer trust
• Legal: Data breaches have severe legal consequences

Security Best Practices

1. Defense in Depth: Multiple layers (API Key, TenantContext, Global Filters)
2. Fail Closed: No data if TenantId missing (throw exception)
3. 404 not 403: Don't leak existence of other tenant's data
4. Audit Everything: Log all tenant context access
5. Test Religiously: 100% integration test coverage

Reference Materials

• Multi-Tenant Security: https://learn.microsoft.com/en-us/ef/core/querying/filters
• Sprint 5 Plan: docs/plans/sprint_5.md