openvpncertupdate/CLAUDE.md

# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## What this is

`openvpncertupdate` is a single-file Python + curses TUI tool for managing OpenVPN user certificates via EasyRSA 3.2.x. It lists expiring/expired certs, re-issues them with fresh keys, creates new certs, and delivers configs via Cryptgeon (one-time password URL) and email. It also supports a non-interactive CLI mode for scripting and cron use.

## Running

```bash
pip install -r requirements.txt   # just: cryptography>=41
python3 openvpncertupdate.py               # interactive TUI
python3 openvpncertupdate.py --create CN --email user@example.com
python3 openvpncertupdate.py --reissue CN [--email user@example.com]
python3 openvpncertupdate.py --revoke CN
python3 openvpncertupdate.py --gen-crl
python3 openvpncertupdate.py --list
python3 openvpncertupdate.py --list-all
```

Edit the `SETTINGS` block at the top of `openvpncertupdate.py` before first run.

### CLI flags

| Flag | Effect |
|---|---|
| `--create CN` | Issue new cert (requires `--email`) |
| `--reissue CN` | Revoke + reissue cert (`--email` optional, falls back to stored) |
| `--revoke CN` | Revoke cert and regenerate CRL |
| `--gen-crl` | Regenerate and copy CRL only |
| `--list` | List recently-expired/soon-to-expire CNs (per `DAYS_PAST`/`DAYS_AHEAD`) with email; read-only, no CA passphrase needed |
| `--list-all` | List all CNs with email; read-only, no CA passphrase needed |
| `--email EMAIL` | Recipient address |
| `--send-email` | Force email delivery |
| `--no-send-email` | Skip email; print URL to stdout |
| `--show-eml` | Print base64-encoded `.eml` to stdout (implies `--no-send-email` unless `--send-email` also given) |
| `--config PATH` | External `.conf` file overriding `SETTINGS` (overrides `CONFIG_PATH`; missing file here is an error) |

## Tests

```bash
python3 -m pytest tests/ -v
python3 -m pytest tests/test_password.py -v            # single file
python3 -m pytest tests/test_pki.py::test_sorted_ascending -v  # single test
```

## File layout — sections inside `openvpncertupdate.py`

| Section | Key symbols |
|---|---|
| SETTINGS | all-caps constants |
| SETTINGS OVERRIDE | `ConfigError`, `load_settings_overrides()`, `_OVERRIDABLE_SETTINGS` |
| PKI | `CertInfo`, `load_expiring_certs()`, `load_all_certs()`, `_parse_index_line()`, `get_email()` |
| PASSWORD | `generate_password()` |
| EASYRSA | `EasyRSAError`, `revoke_issued()`, `build_client_full()`, `gen_crl()`, `copy_crl()`, `is_ca_key_encrypted()`, `resolve_ca_passphrase()` |
| CONFIG | `build_ovpn()` → `vpn-configs/<CN>_<YYYY-MM-DD>_<NN>/CONFIG_NAME` |
| CRYPTGEON | `CryptgeonError`, `create_note()` |
| MAILER | `build_mime_message()`, `send_email()` |
| TUI WIDGETS | `InputField`, `clamp()`, `draw_box()`, `init_colors()`, `COLOR_*` |
| TUI DIALOGS | `show_confirm()`, `show_cert_form()`, `CertFormResult` |
| TUI SCREEN | `show_main_screen()`, `Action`, `ScreenResult` |
| APP | `CursesApp` |
| CLI | `CliRunner`, `_build_parser()` |
| ENTRY POINT | `main()` |

## Re-issue workflow

1. `revoke-issued <CN>` — archives old key + CSR to `pki/revoked/`
2. `build-client-full <CN> --passout=pass:<pw>` — generates new key + cert
3. CRL **not** auto-updated during renewal; use "Regenerate CRL" menu item or `r` hotkey

## TUI key bindings

| Key | Action |
|---|---|
| `↑`/`↓` | Navigate list |
| `Space` | Toggle checkbox selection |
| `Enter` | Confirm / open selected item |
| `r` | Revoke selected cert |
| `A` | Toggle between expiring-only and all-certs view |
| `q`/`Esc` | Quit |

## Key constraints

- External config file (`load_settings_overrides()`, run once in `main()` right after arg parsing, before dispatch): resolution order is `--config PATH` > `CONFIG_PATH` setting > `<this-script-path>.conf` next to the script. The CLI flag or `CONFIG_PATH` make the path explicit — a missing file there is a fatal `ConfigError`; the default `<script>.conf` path is optional and silently skipped if absent. The file is executed as Python (same syntax as the `SETTINGS` block, so only run trusted files) and only names listed in `_OVERRIDABLE_SETTINGS` are applied — `CONFIG_PATH` itself is deliberately not overridable this way
- Email: set `SMTP_HOST` to use smtplib (SMTP_TLS: `"starttls"`/`"ssl"`/`""`); leave empty to use `MAIL_BINARY`. Auth skipped when `SMTP_USER=""`
- EasyRSA called with `--batch`; `--passin=pass:<passphrase>` omitted when the resolved passphrase is empty
- CA passphrase resolution (`resolve_ca_passphrase()`, run once in `main()` right after arg parsing, before dispatch): `CA_PASSPHRASE=""` → auto-detect via `is_ca_key_encrypted()` (checks `<PKI_DIR>/private/ca.key` PEM header for `ENCRYPTED`) and prompt only if encrypted; `"!empty"` → never check/prompt, passphrase is `""`; `"!ask"` → always prompt, skip detection; any other value → used literally. `--list`/`--list-all` skip this resolution entirely since they only read `index.txt` and never touch the CA
- Cryptgeon: matches the `occulto` browser client — `key=os.urandom(32)` used directly (no derivation) for AES-256-GCM; `contents` = `base64(b"AES-GCM") + "--" + base64(nonce) + "--" + base64(ciphertext)`; `meta` = JSON string `{"type": "text"}`; URL = `<base>/note/<id>#<key.hex()>`
- `copy_crl()` does `chmod 644` after copy
- Password: pos 1=uppercase, pos 2=lowercase (no j), pos 3-27=alphanumeric, pos 28=lowercase (no j); `oO01lIQ5S2Z8B` banned everywhere
- Inline file path: `<PKI_DIR>/inline/private/<CN>.inline`
- User emails are not stored separately: `build_client_full()` sets `EASYRSA_REQ_EMAIL` whenever an email is known, which EasyRSA embeds as `emailAddress=` in the cert subject — so it round-trips through `<PKI_DIR>/index.txt` itself. `get_email()` reads it back from there (`load_all_certs()` + CN match); there is no `openvpncertupdate-metadata.json`