jarl/docs/permissions.md

# Users, tokens and permissions

## Ways to authenticate

| Who | How | Notes |
|-----|-----|-------|
| People in the web UI | Username + password → session cookie | argon2id password hashes. The session cookie is HttpOnly and SameSite=Strict and lasts 12h (2h idle). Every change also needs the session's CSRF token, which the UI sends in `X-CSRF-Token`. Changing a password logs out the user's other sessions. |
| CLI, scripts, certbot | API token: `Authorization: Bearer jarl_...` | Shown once at creation, stored hashed. Optional expiry. Revocable. Last use time and IP are recorded. |
| lego / Traefik (`httpreq`) | HTTP Basic: the token's user and the API token | Only on `/api/v1/acme/httpreq/...`, only when `acme.httpreq.enabled` is set, and by default only over HTTPS ([acme.md](acme.md)). The token's grants apply as usual. |
| Root on the server, with the CLI | jarld's local socket (`/run/jarl/jarl.sock`): no token | `sudo jarl ...` with no server configured. The kernel tells jarld which system user is connecting; root and the `jarl` user are administrators, anyone else must send a token. Audited as the system user (e.g. `root`) via `socket`. See [The local socket](#the-local-socket). |
| Root on the server | `jarld` subcommands (`init`, `user`, `import`, `adopt`, `check`, `resync`, `backup`) | Work directly on the database. They are for bootstrapping and recovery, and are audited as "local". |

API tokens are how you give a script, a tool or a person limited access:
a token restricted with grants (below) can, for example, only change TXT
records under `_acme-challenge` in one zone. TSIG keys, on the TSIG keys page,
are something else: shared secrets that BIND servers use to authenticate
each other (zone transfers, NOTIFY); they don't give access to Jarl.

Failed logins are rate limited: 8 per username and 20 per client IP within
15 minutes. Failed token attempts count against the IP too. Every attempt
is in the audit log.

A user **without a password** (`--no-password`) is a service account. It
can't log in to the web UI and is used only through its tokens, which suits
certbot, CI jobs and backups.

## Grants

A user's permissions are a list of grants. Administrators (`admin: true`)
may do everything, and only they can manage users, see everyone's tokens
and run `resync`.

A grant is written as:

```
RESOURCE:ACCESS [zones=PATTERNS] [views=PATTERNS] [names=PATTERNS] [types=TYPES]
```

| Resource | Covers |
|----------|--------|
| `zones` | zone definitions (create, delete, SOA, TTL, view) and zone options |
| `records` | records in primary zones |
| `views` | views and view options |
| `acls` | ACLs |
| `tsig` | TSIG keys (`write` is needed to see a secret) |
| `options` | server options, top-level statements, the defaults for new zones, `jarl check` |
| `audit` | everyone's audit events and changesets (without it, users see only their own) |
| `stats` | query statistics, including client addresses and the names they look up (read only) |
| `*` | all of the above |

`ACCESS` is `read` or `write` (write includes read). Filters narrow a grant.
Each takes comma separated patterns where `*` and `?` are wildcards, and a
missing filter matches everything:

* `zones=adbraun.lol,*.adbraun.lol`: zone names, without the final dot
* `views=internal`: view names (`_default` means zones outside any view)
* `names=_acme-challenge.*`: record owner names, as FQDNs without the final dot
* `types=TXT,CNAME`: record types

Examples:

```
*:read                                                    read everything
records:write zones=lab.adbraun.lol                       edit records in one zone
zones:write zones=*.lab.adbraun.lol                       create/delete zones below lab
records:write zones=adbraun.lol views=internal            only the internal copy of a split zone
records:write names=_acme-challenge.* types=TXT           ACME challenges anywhere
records:write zones=acme.adbraun.lol types=TXT            only TXT records in a dedicated ACME zone
```

A user who may see some records of a zone may also see that the zone exists
(its name and type), but not its other records.

### Roles

Roles are ready-made grant lists. Choosing a role copies its grants, which
you can then edit.

| Role | Grants |
|------|--------|
| `readonly` | `*:read` (includes statistics) |
| `dns-editor` | `zones:write`, `records:write`, `views:read`, `acls:read`, `options:read` |
| `operator` | `*:write` (everything except user management) |
| `acme` | `records:write names=_acme-challenge.* types=TXT` |

```sh
jarl user create alice --role dns-editor
jarl user update alice --grant "records:write zones=adbraun.lol" --grant "zones:read"   # replaces all grants
jarl user update alice --role readonly
```

## Tokens

Every token belongs to a user, and every token request acts as that user.
The audit log shows the user and the token name.

* A token **without grants** has all of its user's permissions, and they
  follow the user: if the user loses a permission, so does the token.
* A token **with grants** is restricted to them. Effective permission is
  *user grants ∩ token grants*: a token can never do more than its user.
  Admin rights don't pass through a restricted token.
* A restricted token can create further tokens, but only ones no wider than
  itself.
* Disabling or deleting a user stops all their tokens at once.

```sh
jarl token create laptop                                  # full rights of the user, no expiry
jarl token create ci --grant "records:write zones=lab.adbraun.lol" --expires 90d
jarl token create certbot --user certbot --role acme       # admin: a token for another user
jarl token list --all
jarl token revoke 12
```

In the web UI: Account → API tokens (your own) and Users → *user* →
Tokens (admin).

### Expiring tokens

A token with an expiry stops working at that moment. So that it doesn't
catch you out (a certbot token that expired breaks renewals silently, until
the certificate itself expires), Jarl warns from **14 days before**:

* the dashboard lists the tokens that expire soon or expired in the last 14
  days (administrators see everyone's, others their own), and token lists
  mark them *soon* or *expired*;
* jarld logs a warning once a day for each of them;
* every response to such a token carries a `Jarl-Token-Expires` header,
  and the `jarl` CLI prints a warning on stderr when it sees it, so the
  logs of the script using the token show it;
* `jarl token list --all --expiring` lists them (`--expiring 60d` looks
  further ahead).

Rotating the token (below) gives it a new lifetime, and keeps its
permissions.

### Rotating a token

Rotating gives a token a **new secret** and changes nothing else: it keeps
its ID, name, user, grants and audit history, so there is nothing to set
up again. Only the programs that use the token need the new secret. Use it
on a schedule, when someone who knew the token leaves, or when it may have
leaked. Revoking is for a token that is no longer needed.

```sh
jarl token rotate 12                          # by ID (see 'jarl token list')
jarl token rotate laptop --save               # by name, and update the CLI's configuration
jarl token rotate deploy --user ci --grace 1h # another user's token (admin), old secret works 1 more hour
jarl token rotate --current --save            # the token this CLI runs with
```

* **The old secret** stops working at once. With `--grace` (at most 7d)
  it keeps working for that long, so clients can be switched over without
  an outage. While it does, jarld logs a warning each time the old secret
  is used (at most once a minute per token and address), with the client's
  IP, so you can find what still needs updating:
  `journalctl -u jarl | grep "old secret"`. `jarl token list` and the web
  UI show when the old secret stops. Rotating again ends the previous grace
  period. If the token may have leaked, rotate without `--grace`.
* **Expiry**: a token that expires gets its lifetime again, counted from
  now, so a 90-day token is good for another 90 days. `--expires 30d` sets
  a new lifetime and `--no-expiry` removes the expiry. A token without an
  expiry keeps having none.
* **Where the new secret goes**: it is printed once, like a new token.
  `--write FILE` writes it to a file instead (an existing file keeps its
  owner and mode; a new one gets mode 0600). `--save` puts it where the CLI
  got its token from: the configuration file (the selected server's entry)
  or the file named in `--token @FILE`. `--save` refuses before rotating
  when the token came from a literal `--token` or `JARL_TOKEN`.
* **Who may rotate**: administrators any token; users their own tokens. A
  restricted token may rotate itself and tokens no wider than itself, but
  not a wider token of its user, since it would learn that token's secret.
  So automation can renew its own token, for example a monthly timer:

  ```sh
  jarl --token @/etc/jarl/certbot.token token rotate --current --save
  ```
* Every rotation is in the audit log (`token.rotate`), with when the old
  secret stops and the new expiry.

In the web UI, the **Rotate** button next to each token asks how long the
old secret should keep working and how long the token should last, then
shows the new secret once.

## The local socket

jarld also listens on a unix socket, `/run/jarl/jarl.sock` (`socket` in
jarl.yaml; systemd creates `/run/jarl`). It serves the same API, but a
request on it without a token is trusted by **who sent it**: the kernel
reports the connecting process's user (`SO_PEERCRED`), and

| Connecting user | Without a token | With a token |
|--|--|--|
| root | administrator | the token's permissions |
| `jarl` (jarld's own user) | administrator | the token's permissions |
| anyone else | refused (401) | the token's permissions |

This gives root nothing it doesn't already have: root can read Jarl's
database, run `jarld user token` and edit named.conf directly. What it adds
is convenience and a way back in: on the server, `sudo jarl status` and
every other command work with nothing configured and no token stored in a
file, even after every token has been revoked and every password
forgotten.

* The socket file is mode 0600 in a 0750 directory owned by `jarl`, so
  other users can't even connect; the user check doesn't depend on that.
* Changes made this way are in the history and audit log under the system
  user's name (`root`) with `socket` as the method. That name isn't a Jarl
  user, so it has no tokens of its own: `sudo jarl token create laptop
  --user admin` makes one for a real user.
* The CLI uses the socket only when no server is configured at all, or
  with `-s local`, so a configured server is never silently swapped for
  the local one ([cli.md](cli.md#on-the-server-itself)).
* Turn it off with `socket: ""` in jarl.yaml.

## Recovering access

Revoking a token never locks you out: tokens and web sessions are
separate. Revoking the token your CLI uses stops only the programs that
use it; you stay logged in to the web UI with your password, with all your
rights, and can make a new token under Account → API tokens. Jarl also
refuses to delete, disable or demote the last administrator.

On the server, root can always use the CLI through the local socket,
without a token:

```sh
sudo jarl whoami
sudo jarl token create laptop --user admin    # a new token for admin
sudo jarl user update admin --password        # a new password
```

The `jarld` subcommands work even when jarld isn't running. As root or the
`jarl` user:

```sh
sudo -u jarl jarld user list
sudo -u jarl jarld user passwd admin          # set a new password and re-enable the account
sudo -u jarl jarld user add --admin rescue    # a new administrator
sudo -u jarl jarld user token admin cli       # a new API token for a user
```