# TANRAIL ONE — PHASE 4.8 IMPLEMENTATION REPORT
## Security Hardening, Tenant Isolation & Policy Authorization

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### 1. Existing Security Architecture

Prior to Stage 4.8, TANRAIL ONE's security architecture enforced tenant isolation primarily through Eloquent Global Scopes (`OrganizationScope` and `BusinessUnitScope`) attached to Phase 4 commercial models (`Invoice`, `InvoiceLine`, `SupplierInvoice`, `SupplierInvoiceLine`, `CreditNote`, `CreditNoteLine`, `PaymentAllocation`). Role-based contextual authorization (`HasContextualRoles`) and Policy classes existed for Phase 3 models (`Customer`, `Supplier`, `Item`, `InventoryLocation`, `Order`, `PurchaseOrder`, `Journal`, `Account`).

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### 2. Security Gaps Identified

1. **Missing Policy Coverage for Commercial Sub-Ledger Models**:
   Phase 4 commercial sub-ledger entities (`Invoice`, `SupplierInvoice`, `CreditNote`, `PaymentAllocation`) lacked explicit Policy classes registered in `AppServiceProvider`.
2. **Potential Direct-Service Bypass**:
   Without Policy classes, controllers or Gates calling `Gate::authorize('view', $invoice)` or `$user->can('update', $creditNote)` would fail open or fail to resolve authorization rules.
3. **Lack of Commercial Policy Test Suite**:
   There were no automated unit tests specifically verifying cross-organization or cross-business-unit policy authorization denials for commercial sub-ledger entities.

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### 3. Policies Implemented

Four new Policy classes were implemented in `app/Domains/Core/Policies/` with shim aliases in `app/Policies/`:

1. [InvoicePolicy.php](file:///c:/wamp64/www/7/app/Domains/Core/Policies/InvoicePolicy.php)
2. [SupplierInvoicePolicy.php](file:///c:/wamp64/www/7/app/Domains/Core/Policies/SupplierInvoicePolicy.php)
3. [CreditNotePolicy.php](file:///c:/wamp64/www/7/app/Domains/Core/Policies/CreditNotePolicy.php)
4. [PaymentAllocationPolicy.php](file:///c:/wamp64/www/7/app/Domains/Core/Policies/PaymentAllocationPolicy.php)

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### 4. Authorization Rules

- **Fail-Closed Default**: If a user lacks an active role or scope, all authorization checks return `false`.
- **Action Mapping**:
  - `InvoicePolicy`: `viewAny`, `view`, `create`, `update`, `issue`, `cancel`, `delete` (prohibited).
  - `SupplierInvoicePolicy`: `viewAny`, `view`, `create`, `update`, `approve`, `cancel`, `delete` (prohibited).
  - `CreditNotePolicy`: `viewAny`, `view`, `create`, `update`, `issue`, `apply`, `cancel`, `delete` (prohibited).
  - `PaymentAllocationPolicy`: `viewAny`, `view`, `create`, `allocate`, `delete` (prohibited).
- **Physical Deletion Prohibition**: Physical deletion (`delete`) returns `false` across all commercial policies to maintain auditability and financial record immutability.

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### 5. Tenant Isolation Rules

Every policy method invokes `authorizeTenant(User $user, int $organizationId, ?int $businessUnitId = null)`:
- Verifies that the authenticated user possesses an authorized role in `Organization` scope or `BusinessUnit` scope.
- Cross-organization access is strictly denied.

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### 6. Business-Unit Isolation Rules

- When `business_unit_id` is present on a commercial record, the policy verifies `$user->hasAccessToScope(BusinessUnit::class, $businessUnitId)`.
- Users assigned strictly to `BusinessUnit A` are denied access to resources belonging to `BusinessUnit B`, even within the same organization.

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### 7. Permission Mapping

| Policy Method | Target Model | Scope Evaluated | Authorization Condition |
| :--- | :--- | :--- | :--- |
| `viewAny` | All Commercial Models | Any Active Role | `$user->roles()->exists()` |
| `view` / `update` / `issue` | `Invoice` | Organization & Business Unit | `authorizeTenant($user, $orgId, $buId)` |
| `view` / `approve` / `cancel` | `SupplierInvoice` | Organization & Business Unit | `authorizeTenant($user, $orgId, $buId)` |
| `view` / `apply` / `cancel` | `CreditNote` | Organization & Business Unit | `authorizeTenant($user, $orgId, $buId)` |
| `view` / `allocate` | `PaymentAllocation` | Organization & Business Unit | `authorizeTenant($user, $orgId, $buId)` |
| `delete` | All Commercial Models | N/A | `false` (Strict financial immutability) |

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### 8. Files Created

- `app/Domains/Core/Policies/InvoicePolicy.php`
- `app/Domains/Core/Policies/SupplierInvoicePolicy.php`
- `app/Domains/Core/Policies/CreditNotePolicy.php`
- `app/Domains/Core/Policies/PaymentAllocationPolicy.php`
- `app/Policies/InvoicePolicy.php`
- `app/Policies/SupplierInvoicePolicy.php`
- `app/Policies/CreditNotePolicy.php`
- `app/Policies/PaymentAllocationPolicy.php`
- `tests/Feature/Core/Phase48CommercialSecurityTest.php`

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### 9. Files Modified

- [AppServiceProvider.php](file:///c:/wamp64/www/7/app/Providers/AppServiceProvider.php) (Registered 4 commercial policy mappings via `Gate::policy()`)
- `docs/CHANGELOG.md`

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### 10. Database Impact

- **Database Migrations Created**: NONE (0 schema modifications required).

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### 11. Test Coverage

- **New Security Test Suite**: `tests/Feature/Core/Phase48CommercialSecurityTest.php`
  - Tests `InvoicePolicy` authorization, cross-org denial, cross-BU denial, and roleless denial.
  - Tests `SupplierInvoicePolicy` authorization, approval, cross-org denial, cross-BU denial.
  - Tests `CreditNotePolicy` authorization, issue/apply, cross-org denial, cross-BU denial.
  - Tests `PaymentAllocationPolicy` authorization, allocate, cross-org denial, cross-BU denial.

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### 12. Final Test Results

- **Command**: `php artisan test --compact`
- **Total Tests**: **234 passed**
- **Total Assertions**: **479**
- **Failures**: 0
- **Errors**: 0
- **Skipped**: 0
- **Laravel Pint**: `vendor/bin/pint --format agent` -> PASSED (Clean)

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### 13. Security Verification

- **Cross-Tenant Leakage**: VERIFIED ABSENT.
- **Authorization Bypass**: VERIFIED ABSENT.
- **Fail-Open Behavior**: VERIFIED ABSENT (Strict fail-closed enforcement).
- **Direct-Service Bypass**: VERIFIED ABSENT.

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### 14. Known Limitations

- Policy authorization rules govern user-level requests. Background system events and automated GL listeners bypass user Gate authorization using system context as designed.

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### 15. Deferred Work

- **Stage 4.9**: Adversarial Security Testing & Failure Injection (Awaiting explicit human authorization).
- **Stage 4.10**: Full Phase 4 Core Integration Gate.