# License Compatibility Analysis

**Document Version:** 1.0.0
**Last Updated:** 2025-12-26
**StellaOps License:** AGPL-3.0-or-later

This document analyzes the compatibility of third-party licenses with StellaOps' AGPL-3.0-or-later license.

---

## 1. AGPL-3.0-or-later Overview

The GNU Affero General Public License v3.0 or later (AGPL-3.0-or-later) is a strong copyleft license that:

1. **Requires** source code disclosure for modifications
2. **Requires** network use disclosure (Section 13) - users interacting over a network must be able to receive the source code
3. **Allows** linking with permissively-licensed code (MIT, Apache-2.0, BSD)
4. **Prohibits** linking with incompatibly-licensed code (GPL-2.0-only, proprietary)

### Key Compatibility Principle

> Code licensed under permissive licenses (MIT, Apache-2.0, BSD, ISC) can be incorporated into AGPL projects. The combined work is distributed under AGPL terms.

---

## 2. License Compatibility Matrix

### 2.1 Fully Compatible (Inbound)

These licenses are fully compatible with AGPL-3.0-or-later. Code under these licenses can be incorporated into StellaOps.

| License | SPDX | Compatibility | Rationale |
|---------|------|---------------|-----------|
| MIT | MIT | **Yes** | Permissive, no copyleft restrictions |
| Apache-2.0 | Apache-2.0 | **Yes** | Permissive, patent grant included |
| BSD-2-Clause | BSD-2-Clause | **Yes** | Permissive, minimal restrictions |
| BSD-3-Clause | BSD-3-Clause | **Yes** | Permissive, no-endorsement clause only |
| ISC | ISC | **Yes** | Functionally equivalent to MIT |
| 0BSD | 0BSD | **Yes** | Public domain equivalent |
| CC0-1.0 | CC0-1.0 | **Yes** | Public domain dedication |
| Unlicense | Unlicense | **Yes** | Public domain dedication |
| PostgreSQL | PostgreSQL | **Yes** | Permissive, similar to MIT/BSD |
| Zlib | Zlib | **Yes** | Permissive |
| WTFPL | WTFPL | **Yes** | Do what you want |

### 2.2 Compatible with Conditions

| License | SPDX | Compatibility | Conditions |
|---------|------|---------------|------------|
| LGPL-2.1-or-later | LGPL-2.1-or-later | **Yes** | Must allow relinking |
| LGPL-3.0-or-later | LGPL-3.0-or-later | **Yes** | Must allow relinking |
| MPL-2.0 | MPL-2.0 | **Yes** | File-level copyleft; MPL code must remain in separate files |
| GPL-3.0-or-later | GPL-3.0-or-later | **Yes** | Combined work is AGPL-3.0+ |
| AGPL-3.0-or-later | AGPL-3.0-or-later | **Yes** | Same license |

### 2.3 Incompatible

These licenses are **NOT** compatible with AGPL-3.0-or-later:

| License | SPDX | Issue |
|---------|------|-------|
| GPL-2.0-only | GPL-2.0-only | Version lock conflicts with AGPL-3.0 |
| SSPL-1.0 | SSPL-1.0 | Additional restrictions |
| Proprietary | LicenseRef-Proprietary | No redistribution rights |
| Commons Clause | LicenseRef-Commons-Clause | Commercial use restrictions |
| BUSL-1.1 | BUSL-1.1 | Production use restrictions |

---

## 3. Distribution Models

### 3.1 Source Distribution (AGPL Compliant)

When distributing StellaOps source code:

```
StellaOps (AGPL-3.0-or-later)
├── StellaOps code (AGPL-3.0-or-later)
├── MIT-licensed deps (retain copyright notices)
├── Apache-2.0 deps (retain NOTICE files)
└── BSD deps (retain copyright notices)
```

**Requirements:**
- Include full AGPL-3.0-or-later license text
- Preserve all third-party copyright notices
- Preserve all NOTICE files from Apache-2.0 dependencies
- Provide complete corresponding source

### 3.2 Binary Distribution (AGPL Compliant)

When distributing StellaOps binaries (containers, packages):

```
StellaOps Binary
├── LICENSE (AGPL-3.0-or-later)
├── NOTICE.md (all attributions)
├── third-party-licenses/ (full license texts)
└── Source availability: git.stella-ops.org
```

**Requirements:**
- Include AGPL-3.0-or-later license
- Include NOTICE file with all attributions
- Provide mechanism to obtain source code
- For network services: provide source access per Section 13

### 3.3 Network Service (Section 13)

StellaOps is primarily deployed as network services. AGPL Section 13 requires:

> If you modify the Program, your modified version must prominently offer all users interacting with it remotely through a computer network [...] an opportunity to receive the Corresponding Source of your version.

**StellaOps Compliance:**
- Source code is available at `https://git.stella-ops.org`
- Web UI includes "Source" link in footer/about page
- API responses include `X-Source-URL` header option
- Documentation includes source availability notice

### 3.4 Aggregation (Not Derivation)

The following are considered **aggregation**, not derivation:

| Scenario | Classification | AGPL Impact |
|----------|---------------|-------------|
| PostgreSQL database | Aggregation | PostgreSQL stays PostgreSQL-licensed |
| RabbitMQ message broker | Aggregation | RabbitMQ stays MPL-2.0 |
| Docker containers | Aggregation | Base image licenses unaffected |
| Kubernetes orchestration | Aggregation | K8s stays Apache-2.0 |
| Hardware (HSM) | Interface only | HSM license unaffected |

**Rationale:** These components communicate via network protocols, APIs, or standard interfaces. They are not linked into StellaOps binaries.

---

## 4. Specific Dependency Analysis

### 4.1 BouncyCastle Cryptography (MIT)

| Aspect | Status |
|--------|--------|
| License | MIT |
| Compatibility | Full |
| Usage | Linked into binaries |
| Requirement | Include copyright notice in NOTICE.md |

### 4.2 Npgsql/PostgreSQL (PostgreSQL License)

| Aspect | Status |
|--------|--------|
| License | PostgreSQL (permissive) |
| Compatibility | Full |
| Usage | NuGet package (linked) |
| Requirement | Include copyright notice in NOTICE.md |

### 4.3 Polly (BSD-3-Clause)

| Aspect | Status |
|--------|--------|
| License | BSD-3-Clause |
| Compatibility | Full |
| Usage | NuGet package (linked) |
| Requirement | Include copyright notice; no endorsement claims |

### 4.4 RxJS (Apache-2.0)

| Aspect | Status |
|--------|--------|
| License | Apache-2.0 |
| Compatibility | Full |
| Usage | npm package (bundled in frontend) |
| Requirement | Preserve NOTICE file |

### 4.5 CryptoPro CSP (Commercial)

| Aspect | Status |
|--------|--------|
| License | Commercial (LicenseRef-CryptoPro) |
| Compatibility | N/A - Not distributed |
| Usage | PKCS#11 interface only |
| Requirement | Customer obtains own license |

**Analysis:** StellaOps provides only the integration code (AGPL-3.0-or-later). CryptoPro CSP binaries are never distributed by StellaOps. This is a clean separation:

```
StellaOps Ships:
├── PKCS#11 interface code (AGPL-3.0-or-later)
├── Configuration documentation
└── Integration tests (mock only)

Customer Provides:
├── CryptoPro CSP license
├── CryptoPro CSP binaries
└── Hardware tokens (optional)
```

### 4.6 AlexMAS.GostCryptography (MIT)

| Aspect | Status |
|--------|--------|
| License | MIT |
| Compatibility | Full |
| Usage | Source vendored |
| Requirement | Include copyright notice; license file preserved |

**Analysis:** The fork is MIT-licensed and compatible with AGPL-3.0-or-later. The combined work (StellaOps + fork) is distributed under AGPL-3.0-or-later terms.

### 4.7 axe-core/Playwright (@axe-core/playwright - MPL-2.0)

| Aspect | Status |
|--------|--------|
| License | MPL-2.0 |
| Compatibility | Yes (with conditions) |
| Usage | Dev dependency only |
| Requirement | MPL files stay in separate files |

**Analysis:** MPL-2.0 is file-level copyleft. Since this is a dev dependency used only for accessibility testing (not distributed in production), there are no special requirements for end-user distribution.

---

## 5. Outbound Licensing

### 5.1 StellaOps Core

All StellaOps-authored code is licensed under AGPL-3.0-or-later:

```
SPDX-License-Identifier: AGPL-3.0-or-later
Copyright (C) 2025 stella-ops.org
```

### 5.2 Documentation

Documentation is licensed under:
- Code examples: AGPL-3.0-or-later (same as source)
- Prose content: CC-BY-4.0 (where specified)
- API specifications: AGPL-3.0-or-later

### 5.3 Configuration Samples

Sample configuration files (`etc/*.yaml.sample`) are:
- Licensed under: AGPL-3.0-or-later
- Derived configurations by users: User's choice (no copyleft propagation for configuration)

---

## 6. Compliance Checklist

### 6.1 For StellaOps Maintainers

- [ ] All new dependencies checked against allowlist
- [ ] NOTICE.md updated for new MIT/Apache-2.0/BSD dependencies
- [ ] third-party-licenses/ includes texts for vendored code
- [ ] No GPL-2.0-only or incompatible licenses introduced
- [ ] Source remains available at documented URL

### 6.2 For StellaOps Operators (Self-Hosted)

- [ ] Source code available to network users (link in UI/docs)
- [ ] Modifications (if any) made available under AGPL-3.0-or-later
- [ ] Commercial components (CryptoPro, HSM) separately licensed
- [ ] NOTICE file preserved in deployment

### 6.3 For Contributors

- [ ] New code contributed under AGPL-3.0-or-later
- [ ] No proprietary code introduced
- [ ] Third-party code properly attributed
- [ ] License headers in new files

---

## 7. FAQ

### Q: Can I use StellaOps commercially?
**A:** Yes. AGPL-3.0-or-later permits commercial use. You must provide source code access to users interacting with your deployment over a network.

### Q: Can I modify StellaOps for internal use?
**A:** Yes. If modifications are internal only (not exposed to network users), no disclosure required.

### Q: Does using StellaOps make my data AGPL-licensed?
**A:** No. AGPL applies to software, not data processed by the software. Your SBOMs, vulnerability data, and configurations remain yours.

### Q: Can I integrate StellaOps with proprietary systems?
**A:** Yes, via API/network interfaces. This is aggregation, not derivation. Your proprietary systems retain their licenses.

### Q: Do I need to disclose my CryptoPro CSP license?
**A:** CryptoPro CSP is customer-provided. StellaOps only ships integration code. Your CSP license is between you and CryptoPro.

---

## 8. References

- [GNU AGPL-3.0 FAQ](https://www.gnu.org/licenses/gpl-faq.html)
- [FSF License Compatibility](https://www.gnu.org/licenses/license-list.html)
- [SPDX License List](https://spdx.org/licenses/)
- [Apache-2.0/GPL Compatibility](https://www.apache.org/licenses/GPL-compatibility.html)
- [REUSE Best Practices](https://reuse.software/tutorial/)

---

*Document maintained by: Legal + Security Guild*
*Last review: 2025-12-26*