Cert services: Self-signed and ACME with DNS challenge

[mvdschee]

This PR adds the long awaited feature to support real SSL certificates without exposing a local server to the internet, it only supports DNS challenge, which is automated for CloudFlare (will add more later on) so we dont need to do anything ourself every 30 days.

[Copilot]

🟡 Changes recommended

Certificate handling has unresolved TLS correctness, renewal recovery, and secret-permission issues.

9 open findings

• Preserve and install intermediate certificates from the PEM chain · New
• Replace existing self-signed certificates when switching to ACME · New
• Restrict permissions on ACME credentials and private keys · New
• Skip ACME account initialization without eligible routes · New
• Retry ACME account initialization after temporary failures · New
• Persist order state before DNS setup and track completion · New
• Retain pending order keys and resume certificate retrieval · New
• Atomically publish certificate and key generations · New
• Update only proxy-managed ACME DNS challenge records · New

What changed in this PR

Adds ACME DNS-01 certificate issuance and renewal to the reverse proxy, alongside self-signed certificates and live TLS updates.

Changes:

• Adds Cloudflare DNS challenges and persistent ACME accounts.
• Integrates background renewal and an atomically replaceable TLS store.
• Updates configuration, dependencies, examples, and documentation.

File	Description
src/​utils.rs	Adds reusable string-newtype macro.
src/​services/​mod.rs	Registers service modules.
src/​services/​http/​mod.rs	Creates shared HTTP clients.
src/​services/​dns/​utils.rs	Builds challenge record names.
src/​services/​dns/​resolver.rs	Looks up challenge TXT records.
src/​services/​dns/​mod.rs	Registers DNS modules.
src/​services/​dns/​cloudflare.rs	Creates and updates challenge records.
src/​services/​certs/​self_signed.rs	Generates self-signed certificate files.
src/​services/​certs/​mod.rs	Registers certificate services.
src/​services/​certs/​acme.rs	Manages ACME accounts and orders.
src/​main.rs	Connects certificate renewal to proxy startup.
src/​error.rs	Adds service error types.
src/​core/​setup.rs	Initializes TLS storage and renewal.
src/​core/​models/​tasks.rs	Documents interval units.
src/​core/​models/​routes.rs	Adds DNS-provider configuration.
src/​core/​models/​proxy.rs	Removes per-route certificate paths.
src/​core/​models/​mod.rs	Exposes new model modules.
src/​core/​models/​filesystem.rs	Reuses string-newtype macro.
src/​core/​models/​dns.rs	Defines DNS providers and credentials.
src/​core/​models/​config.rs	Centralizes configuration models.
src/​core/​models/​certs.rs	Adds renewal state and shared TLS storage.
src/​core/​handlers/​proxy.rs	Uses live certificates and background renewal.
src/​core/​handlers/​certs.rs	Implements certificate issuance and renewal.
src/​config.rs	Adds ACME settings and renewal intervals.
README.md	Documents certificate workflows and deployment.
makefile	Updates local development settings.
example/​example.toml	Demonstrates Cloudflare ACME configuration.
docker-compose.yml	Updates comments and removes temporary mount.
Cargo.toml	Updates dependencies and package version.
Cargo.lock	Records dependency changes.
.rustfmt.toml	Configures import grouping.
.foxguard/​baseline.json	Changes trailing newline only.
.foxguard.yml	Disables a dependency-scanning rule.

🧠 Review effort: Balanced

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Copilot]

🟡 Changes recommended

ACME account recovery and certificate publication can cause repeated registrations or leave unusable certificate files.

1 open finding

• Propagate existing account file read and parse errors · New

9 resolved since last review

• Restrict permissions on ACME credentials and private keys
• Replace existing self-signed certificates when switching to ACME
• Preserve and install intermediate certificates from the PEM chain
• Update only proxy-managed ACME DNS challenge records
• Atomically publish certificate and key generations
• Retain pending order keys and resume certificate retrieval
• Persist order state before DNS setup and track completion
• Retry ACME account initialization after temporary failures
• Skip ACME account initialization without eligible routes

Previously missed (3)

In code that hasn't changed since last review

Reject invalid ACME environment values

src/​services/​certs/​acme.rs:39

Every value except exactly production silently selects staging. A typo such as prodution therefore issues an untrusted staging certificate and takes the route offline instead of reporting bad configuration. Accept the two documented values explicitly and reject anything else.

Check Cloudflare response status before JSON parsing

src/​services/​dns/​cloudflare.rs:143

Unlike the lookup and update paths, record creation does not inspect the HTTP status. Cloudflare 4xx/5xx responses are consequently fed to serde_json and reported as misleading parse errors instead of the API failure status. Check response.status() before consuming the body.

Correct ACME environment documentation and precedence

README.md:114

This contradicts the implementation: ACME_ENV=staging selects Let's Encrypt staging, while production is only the default. Documenting this incorrectly encourages testing against production rate limits; also note that an existing account file takes precedence over the environment setting.

🧠 Review effort: Balanced