# Linux_Patch_Manager - Requirements Document

## Project Overview
**Title:** Linux_Patch_Manager
**Version:** 0.0.1
**Status:** Draft

## Functional Requirements

### FR-01: Host Management

- Manual host registration by FQDN or IP address (FQDN resolved to IP at add time)
- On-demand auto-discovery targeting a CIDR subnet range (scans for Linux Patch API agents on port 12443)
- Host metadata tracked: hostname, IP, OS, kernel, agent version, last seen, health status
- Static group-based organization with many-to-many relationships (hosts can belong to multiple groups)
- Ungrouped hosts can be managed by any operator or admin
- Host removal with audit logging

### FR-02: Patch Monitoring

- Scheduled background polling: 5-minute intervals for health checks, 30-minute intervals for patch data
- On-demand refresh triggered by operator/admin from the UI
- Visual dashboard alerts for unhealthy or unreachable agents (red/yellow status indicators)
- CVE severity, patch priority, and reboot requirement display per host

### FR-03: Patch Deployment

- Patches queue for the next available maintenance window by default
- Immediate-apply override option for urgent patches
- No approval gate required — operator/admin triggers deployment directly
- Auto-retry failed patch jobs once if still within the maintenance window, then surface failure prominently
- Batch operations across multiple hosts with partial failure handling (auto-retry once, then report failures)
- Rollback support via upstream Linux Patch API rollback endpoint

### FR-04: Scheduling

- Maintenance windows are per-device (not per-group)
- Recurring schedules: daily, weekly, or monthly
- One-time maintenance windows
- Patch operations execute automatically when a maintenance window opens

### FR-05: Reporting

- Compliance report: percentage of hosts fully patched, by group or fleet-wide
- Patch history: log of all patch operations per host or per group
- Vulnerability exposure: hosts with known CVEs pending patches
- Audit trail: who did what when (user actions, patch operations)
- Export formats: CSV and PDF

### FR-06: User Management

- **Admin role**: Full access to manage all aspects of Linux Patch Manager
- **Operator role**: Can add/remove clients, manage schedules and patches only for devices in their group memberships
- Operators can belong to multiple groups
- Local accounts with MFA required (TOTP or WebAuthn)
- Azure SSO integration (optional, with Azure's built-in MFA)
- Group membership management for users and hosts

## Non-Functional Requirements

### NFR-01: Security

- Combination authentication: local accounts + Azure SSO
- MFA required for all users (TOTP or WebAuthn; Azure MFA for SSO users)
- Session management: short-lived JWT access tokens (15 min) + server-side refresh tokens (1-hour inactivity timeout, revocable)
- mTLS for all agent communication (certificate-based, TLS 1.3 only)
- HTTPS enforced for web UI
- Internal CA managed by Patch Manager for mTLS certificate issuance and renewal
- Certificate distribution to managed clients is manual (server administrators responsible)
- RBAC with group-scoped access control

### NFR-02: Performance

- Support 500 typical managed hosts, up to 2,500
- Dashboard load time under 5 seconds for full fleet view
- Background polling must not degrade UI responsiveness
- Concurrent batch operations (e.g., patch 500 hosts simultaneously) must not overwhelm the system

### NFR-03: Scalability

- Single-instance design on bare metal/VM (Ubuntu 24.04)
- Manual horizontal scaling by dividing clients between multiple Patch Manager hosts if needed
- No automatic clustering or load balancing required

### NFR-04: Reliability

- Agent communication failures: retry with exponential backoff (3 retries, max 30 minutes between retries)
- Patch job failures: auto-retry once within maintenance window, then surface to operators
- Batch partial failures: auto-retry once, then report remaining failures to operator
- Continue processing healthy hosts regardless of individual host failures

### NFR-05: Usability

- 11-page web UI (React + TypeScript SPA)
- Responsive design for desktop/laptop screens
- Dark mode support
- Certificate download links integrated into dashboard (root CA) and host detail (host-specific mTLS)

## Interface Requirements

### IR-01: Web Interface

- React + TypeScript SPA served by Axum backend
- Real-time job status via WebSocket relay (agent WebSocket → Patch Manager → browser)
- RESTful API backend for all UI operations
- Certificate download endpoints for root CA and host-specific mTLS certs

### IR-02: Linux Patch API Integration

- All managed device communication via Linux Patch API (upstream agent)
- mTLS client certificate authentication to each agent
- Base path: `/api/v1/`, Port: 12443, TLS 1.3 only
- Sync operations: GET endpoints (packages, patches, system info, health)
- Async operations: POST/PUT/DELETE endpoints (install, update, remove, patch apply, reboot)
- Job status tracking via GET `/api/v1/jobs/{id}` and WebSocket `/api/v1/ws/jobs`
- Rollback via POST `/api/v1/jobs/{id}/rollback`

## Data Requirements

- **Database:** PostgreSQL
- **Operational data retention:** 30 days (host patch history, job history, health history)
- **Audit log retention:** 6 months
- **Data storage:** All data on Patch Manager host

## Compliance Requirements

### HIPAA (Health Insurance Portability and Accountability Act)

- **Audit Controls (§164.312(b)):** Comprehensive audit logging of all system activity (covered by audit logging requirements)
- **Access Controls (§164.312(a)(1)):** RBAC with group-scoped access, unique user identification, MFA enforcement
- **Integrity Controls (§164.312(c)(1)):** Audit log integrity protection (tamper-evident logging)
- **Transmission Security (§164.312(e)(1)):** mTLS for all agent communication, HTTPS for web UI, TLS 1.3 minimum
- **Encryption at Rest:** PostgreSQL data encryption (full-disk or column-level for sensitive fields)
- **Automatic Logoff (§164.312(a)(2)(iii)):** 1-hour inactivity session timeout

### PCI-DSS (Payment Card Industry Data Security Standard)

- **Requirement 6:** Vulnerability management — patch management is core PCI-DSS requirement; system must track and enforce timely patching
- **Requirement 7:** Restrict access to need-to-know — RBAC with group-scoped operator access
- **Requirement 8:** Identify and authenticate users — MFA required, unique IDs, session timeouts
- **Requirement 10:** Track and monitor all access — comprehensive audit logging with 6-month retention
- **Requirement 3:** Protect stored data — encryption at rest for PostgreSQL
- **Requirement 4:** Encrypt transmission — mTLS (TLS 1.3) for agent communication, HTTPS for web UI

## Constraints

- Single bare metal/VM host running Ubuntu 24.04
- Systemd service management
- Internal network only (no public internet exposure)
- Rust/Axum backend, React/TypeScript frontend, PostgreSQL database
- No direct permissions on managed clients
- Certificate distribution to clients is manual