# 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 --create CN --email user@example.com --days 90
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 + regenerate CRL + 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. Both `--list`/`--list-all` grow a trailing `CERT` column marking `MISSING` CNs — see `CertInfo.has_cert_file`. The column is omitted entirely when every CN has its `.crt` |
| `--email EMAIL` | Recipient address |
| `--days N` | Certificate lifetime in days for `--create`/`--reissue`; overrides `CERT_DAYS` for that run |
| `--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_current_certs()`, `load_expiring_certs()`, `load_all_certs()`, `_parse_index_line()`, `get_email()` |
| PASSWORD | `generate_password()` |
| EASYRSA | `EasyRSAError`, `_easyrsa_diagnostics()`, `issued_cert_path()`, `has_issued_cert()`, `revoke_issued()`, `build_client_full()`, `gen_crl()`, `copy_crl()`, `is_ca_key_encrypted()`, `resolve_ca_passphrase()`, `resolve_cert_days()` |
| 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

0. `has_issued_cert()` gates steps 1–2: if `<PKI_DIR>/issued/<CN>.crt` is absent, both are **skipped** with a warning and the workflow goes straight to step 3. EasyRSA reads the serial out of the `.crt` itself, so `revoke-issued` can only fail on such a CN — and there is nothing to add to the CRL either. This happens when an `index.txt` is carried over from an older EasyRSA install without the `issued/` files: the index still lists V-status certs whose `.crt` never came along. `--revoke` / the TUI `r` key deliberately do *not* skip — an explicit revoke request should fail loudly rather than silently no-op. Such CNs are flagged before the user picks one: `_load_current_certs()` sets `CertInfo.has_cert_file` (one stat per CN, after the dedup), rendered as `(no cert)` before the email in the TUI list and as a `MISSING` cell in the `CERT` column of `--list`/`--list-all`. Two guards bound the skip so it can't silently do the wrong thing: (a) on the CLI, the skip only fires for a CN that `_load_current_certs()` actually knows about — a typo'd/nonexistent `--reissue CN` is *not* a migration gap and is rejected with `error: unknown CN ...` before anything is built (the TUI can't hit this: renewal always opens on an existing row, so the CN is never freeform there); (b) whichever entry point takes the skip, it first checks for leftover `pki/reqs/<CN>.req` / `pki/private/<CN>.key` — normally `revoke-issued` archives both into `pki/revoked/`, but skipping it leaves them in place, and EasyRSA's `build-client-full` aborts outright rather than overwrite them. Either leftover fails the workflow fast with the exact path(s), before the CA passphrase prompt — this tool never moves or deletes a private key itself
1. `revoke-issued <CN>` — archives old key + CSR to `pki/revoked/`
2. CRL regenerated and copied to `CRL_DEST_PATH` immediately after the revoke succeeds — the old cert is already revoked at this point, so the published CRL would otherwise be stale until a separate manual regen. Not fatal: a failure here is reported but the workflow continues to step 3 (a new cert is more urgent than a fresh CRL, and "Regenerate CRL" / `--gen-crl` remain available to retry)
3. `build-client-full <CN> --passout=pass:<pw>` — generates new key + cert

## 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
- EasyRSA error text arrives on **stdout**, not stderr: its `print()` is `printf '%s\n'`, and both `die()` and `user_error()` route through it. stderr only carries output from the tools EasyRSA shells out to (openssl), and even that is silenced under `-S/--silent-ssl` (not passed here). `_easyrsa_diagnostics()` therefore merges both streams — building an error from stderr alone reports failures as blank
- 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
- Certificate lifetime (`resolve_cert_days()`, run once in `main()` right after the config overrides are applied — before the `--list` early return, since it validates config and never prompts): `CERT_DAYS = "default"` or `""` → omit `--days` entirely and let EasyRSA's own `EASYRSA_CERT_EXPIRE` (from `vars`) decide; a positive number → passed as `--days=N`, normalised so `"090"` becomes `"90"`. `0`, negatives and non-numeric values raise `ConfigError` — a fast-fail mirror of EasyRSA's own gate (`Cannot use --days=0 for command build-client-full`), not a substitute for it. `--days N` overrides `CERT_DAYS` for one CLI run; the TUI's Days field overrides it per certificate. The flag is added in `build_client_full()` only, never in `_base_cmd()` — `gen-crl` reads `--days` as CRL validity
- 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, then runs `RESTORECON_BINARY` (default `restorecon`) on the copied file — best-effort like `is_ca_key_encrypted()`: a missing/misconfigured binary is swallowed, not fatal. Set `RESTORECON_BINARY=""` to disable on non-SELinux systems
- 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; there is no `openvpncertupdate-metadata.json`
- `index.txt` is append-only and a CN can accumulate multiple V-status lines (e.g. left unrevoked after expiring, then reissued) alongside older R-status ones. `_load_current_certs()` is the single place that resolves this: keeps only the last (most recently appended) V-status line per CN. `load_expiring_certs()`, `load_all_certs()`, and `get_email()` all build on it, so the TUI list, `--list`/`--list-all`, and email lookups never show/use a stale duplicate