# checker-email-keys

DANE-Email posture checker for happyDomain.

Runs a comprehensive testsuite on a domain's DNS-published OpenPGP key
(`OPENPGPKEY`, [RFC 7929][rfc7929]) or S/MIME certificate (`SMIMEA`,
[RFC 8162][rfc8162]) and renders an actionable HTML report whose top
block nudges the user toward the fix for the most common failure
scenarios.

This checker binds to the happyDomain services:

- `abstract.OpenPGP`: individual user's PGP key, owner-hashed below
  `._openpgpkey.<zone>`.
- `abstract.SMimeCert`: user's S/MIME certificate, owner-hashed below
  `._smimecert.<zone>`.

[rfc7929]: https://www.rfc-editor.org/rfc/rfc7929
[rfc8162]: https://www.rfc-editor.org/rfc/rfc8162

## Tests run

All findings are tagged by severity (`info` / `warn` / `crit`) so the
rule engine can fold them into a single `CheckState`.

### DNS (both record types)

| Code | Severity | What it catches |
| --- | --- | --- |
| `dns_query_failed` | crit | The resolver returned an error or did not answer. |
| `dns_no_record` | crit | The authoritative answer has no record at the expected owner. |
| `dnssec_not_validated` | crit / warn | The validating resolver did not set `AD`. RFC 7929/8162 mandate DNSSEC; the severity is configurable via `requireDNSSEC`. |
| `dns_record_mismatch` | warn | The record returned by DNS differs from the one declared in the service (typically a stale zone on the authoritative servers). |
| `owner_hash_mismatch` | crit | Record owner-name first label is not `sha256(localpart)[:28]`; mail clients will never find it. |

### OpenPGP-specific (RFC 7929)

| Code | Severity | What it catches |
| --- | --- | --- |
| `pgp_parse_error` | crit | Malformed base64 or OpenPGP packet stream. |
| `pgp_no_entity` | crit | Record decoded but carries no valid entity. |
| `pgp_primary_revoked` | crit | Primary key has a revocation signature. |
| `pgp_primary_expired` | crit | Self-signature expired; clients will refuse to encrypt. |
| `pgp_primary_expiring_soon` | warn | Expires within the `certExpiryWarnDays` window (default 30). |
| `pgp_weak_algorithm` | warn | Uses DSA / ElGamal (phase-out). |
| `pgp_weak_key_size` | crit / warn | RSA below 2048 bits is critical, 2048-3071 is a warn. |
| `pgp_no_encryption_subkey` | crit | No active key in the entity advertises encryption capability. |
| `pgp_no_identity` | warn | No self-signed User ID. |
| `pgp_uid_mismatch` | info | None of the UIDs reference `<username@…>`. |
| `pgp_multiple_entities` | warn | Record carries more than one entity (RFC 7929 recommends one). |
| `pgp_record_too_large` | warn | Raw key > 4 KiB; forces UDP→TCP fallback on every lookup. |

### SMIMEA-specific (RFC 8162)

| Code | Severity | What it catches |
| --- | --- | --- |
| `smimea_bad_usage` / `_selector` / `_match_type` | crit | Field outside the allowed range. |
| `smimea_cert_parse_error` | crit | Hex-encoded blob is not a valid X.509 certificate / SPKI. |
| `smimea_cert_expired` / `_not_yet_valid` | crit | `notBefore` / `notAfter` gate the current time out. |
| `smimea_cert_expiring_soon` | warn | Within the `certExpiryWarnDays` window. |
| `smimea_no_email_protection_eku` | crit / warn | Missing `emailProtection` EKU (RFC 8550/8551 agents will reject). |
| `smimea_missing_key_usage` | warn | Neither `digitalSignature` nor `keyEncipherment` key-usage is set. |
| `smimea_email_mismatch` | info | No email SAN starts with `<username>@`. |
| `smimea_weak_signature_algorithm` | crit | MD5 / SHA-1 based signature. |
| `smimea_weak_key_size` | crit / warn | RSA < 2048 / 3072 bits. |
| `smimea_self_signed` | info | Self-signed certificate paired with PKIX-EE usage. |
| `smimea_hash_only` | info | Matching-type 1/2 only carries a digest; certificate can't be inspected. |

## Options

| Id | Type | Default | Description |
| --- | --- | --- | --- |
| `resolver` | string | *(system)* | Validating resolver to query; comma-separated list accepted. |
| `certExpiryWarnDays` | number | 30 | Raise an `expiring_soon` warning within this window. |
| `requireDNSSEC` | bool | true | When false, missing AD is a warn instead of crit. |
| `requireEmailProtection` | bool | true | When false, missing `emailProtection` EKU is a warn instead of crit. |

Auto-filled by the host: `domain_name`, `subdomain`, `service`,
`service_type`.

## Running

```bash
# Plugin (loaded by happyDomain at startup)
make plugin

# Standalone HTTP server
make && ./checker-email-keys -listen :8080
```