Add per-user logins alongside the shared password

The dashboard had one shared password and no concept of a user. This
adds real accounts: a username field on the login page, per-user
credentials, and the signed-in user recorded on the session, which is
the groundwork for per-user permissions later.

Credentials are salted pbkdf2 hashes in settings.json's `users` map.
Three deliberate choices there:

- settings.json rather than an env var, because a pbkdf2 hash contains
  '$' and docker compose interpolates that when it reads .env. It's also
  already the bind-mounted file that survives `up -d --build`.
- pbkdf2 rather than Werkzeug's default scrypt, which needs a hashlib
  built against OpenSSL — the macOS system Python has no hashlib.scrypt
  and would raise at hash time.
- load_users() re-reads the file per check, so adding a user or changing
  a password is live in every gunicorn worker with no restart. The old
  _runtime_password was per-worker and only ever half-applied.

Multi-user activates only once an account exists. Until then the
original LOGIN_PASSWORD path is used unchanged and the username field is
hidden, so deploying this can't lock the existing install out.
manage_users.py prompts for passwords via getpass — never echoed, never
a CLI argument — and only ever writes hashes; it refuses to remove the
last account, which would silently drop the dashboard back to the shared
password.

Two fixes carried along: login no longer requires the LOGIN_PASSWORD env
var specifically, so a settings.json-only password works instead of
locking you out; and the legacy comparison now uses hmac.compare_digest,
which the old docstring claimed but '==' didn't provide.

Also gitignores settings.json and data/ — they hold API keys and now
password hashes, were excluded from the deploy rsync but not from git.

Verified: legacy fallback still signs in with no accounts configured; a
9-case credential matrix (right/wrong user x right/wrong password, plus
the retired shared password); per-user change-password scoped to the
signed-in account and live without restart; and the add/passwd/remove
guards.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.gitignore

@@ -2,3 +2,9 @@
 __pycache__/
 *.pyc
 .DS_Store
+
+# Runtime settings — API-key overrides, timezone, and the `users` map of
+# password hashes. Already excluded from the deploy rsync; keep it out of
+# git too so credentials can't be committed by accident.
+settings.json
+data/

CLAUDE.md

@@ -232,6 +232,48 @@ silently discards it. `data/` is likewise excluded from the deploy
 rsync, which runs `--delete` and would otherwise remove it for not
 being in the repo.
 
+## Logins
+
+Two modes, chosen by whether `settings.json` holds a non-empty `users` map:
+
+- **Multi-user** (once any account exists): username + password, each
+  password stored as a salted pbkdf2 hash under `users` in `settings.json`.
+  `verify_credentials()` is the only entry point; `load_users()` re-reads
+  the file per check, so adding a user or changing a password is live
+  immediately in every gunicorn worker — no restart, unlike the API keys.
+- **Legacy single shared password** (no accounts yet): the original
+  `LOGIN_PASSWORD` / `settings.json.login_password` path, username ignored.
+  This fallback exists so deploying multi-user support can't lock an
+  existing install out; the login page hides the username field entirely
+  until accounts exist.
+
+Manage accounts with `manage_users.py`, which prompts for passwords
+(never echoed, never a CLI argument, so they stay out of shell history)
+and only ever writes hashes:
+
+```bash
+docker exec -it arr-summary python3 manage_users.py list
+docker exec -it arr-summary python3 manage_users.py add <username>
+docker exec -it arr-summary python3 manage_users.py passwd <username>
+docker exec -it arr-summary python3 manage_users.py remove <username>
+```
+
+**Adding the first account switches the whole dashboard to per-user
+logins and the shared password stops working** — verify you can sign in
+as that user before closing the shell. `remove` refuses to delete the
+last account for the same reason.
+
+Users live in `settings.json` rather than an env var deliberately: a
+pbkdf2 hash contains `$`, which docker compose interpolates when reading
+`.env`. `PASSWORD_HASH_METHOD` is pinned to pbkdf2 rather than Werkzeug's
+default scrypt, which needs a hashlib built against OpenSSL and is absent
+on the macOS system Python.
+
+**Never put a real password in the repo** — not in `app.py`, not in
+`settings.json` committed to git, not in a fixture. `.env` and `data/`
+are gitignored and excluded from the deploy rsync precisely so secrets
+have somewhere to live; everything else here is pushed to Forgejo.
+
 A key saved through the Settings page overrides the corresponding
 `.env` value at startup (see the block after the `*_API_KEY` reads in
 `app.py`); `.env` remains the source of truth for anything never

app.py

@@ -2,6 +2,7 @@ import os
 import re
 import json
 import time
+import hmac
 import hashlib
 import secrets
 import requests
@@ -11,6 +12,7 @@ from datetime import datetime, timedelta
 from functools import wraps
 from concurrent.futures import ThreadPoolExecutor, as_completed
 from flask import Flask, render_template, request, jsonify, redirect, url_for, session
+from werkzeug.security import generate_password_hash, check_password_hash
 
 # Suppress SSL warnings for Unraid's self-signed certificate
 urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
@@ -134,6 +136,12 @@ def inject_version():
 LOGIN_PASSWORD = os.environ.get("LOGIN_PASSWORD", "")
 _runtime_password = None  # overrides env var after change-password call
 
+# scrypt (Werkzeug's default) needs a hashlib built against OpenSSL, which
+# isn't guaranteed — the macOS system Python has no hashlib.scrypt at all.
+# pbkdf2 is pure hashlib and available everywhere this runs.
+PASSWORD_HASH_METHOD = "pbkdf2:sha256"
+_dummy_hash = None  # lazily built; see verify_credentials
+
 
 def get_active_password():
     if _runtime_password is not None:
@@ -145,9 +153,57 @@ def get_active_password():
     return LOGIN_PASSWORD
 
 def _hash_password(pw):
-    """SHA-256 hash for constant-time comparison."""
+    """SHA-256 of the legacy single shared password.
+
+    Only used for the pre-multi-user fallback below. New accounts are hashed
+    with pbkdf2 + a per-user salt via load_users()/verify_credentials.
+    """
     return hashlib.sha256(pw.encode()).hexdigest()
 
+
+def load_users():
+    """Username -> pbkdf2 hash, read fresh from settings.json.
+
+    Users live in settings.json rather than an env var for two reasons: a
+    pbkdf2 hash contains '$', which docker compose interpolates when it reads
+    .env, and settings.json is already the bind-mounted file that survives
+    `up -d --build`. Reading it per-call also means an added user takes effect
+    without a restart, and applies to every gunicorn worker at once.
+    """
+    users = load_settings().get("users") or {}
+    if not isinstance(users, dict):
+        return {}
+    return {u: h for u, h in users.items() if isinstance(h, str) and h}
+
+
+def verify_credentials(username, password):
+    """True if these credentials are valid.
+
+    Multi-user as soon as settings.json holds a non-empty `users` map;
+    until then this falls back to the original single shared password so
+    deploying this doesn't lock an existing install out. The username is
+    ignored on that legacy path.
+    """
+    global _dummy_hash
+    users = load_users()
+    if users:
+        stored = users.get(username)
+        if not stored:
+            # Verify against a throwaway hash anyway, so a wrong username
+            # costs the same time as a wrong password and can't be probed.
+            if _dummy_hash is None:
+                _dummy_hash = generate_password_hash(
+                    secrets.token_hex(16), method=PASSWORD_HASH_METHOD
+                )
+            check_password_hash(_dummy_hash, password)
+            return False
+        return check_password_hash(stored, password)
+
+    active = get_active_password()
+    if not active:
+        return False
+    return hmac.compare_digest(_hash_password(password), _hash_password(active))
+
 def login_required(f):
     @wraps(f)
     def decorated(*args, **kwargs):
@@ -1013,20 +1069,25 @@ def get_rt_tv():
 @app.route("/login", methods=["GET", "POST"])
 def login():
     error = None
+    multi_user = bool(load_users())
     if request.method == "POST":
+        username = request.form.get("username", "").strip()
         entered = request.form.get("password", "")
-        if LOGIN_PASSWORD and _hash_password(entered) == _hash_password(get_active_password()):
+        if verify_credentials(username, entered):
             session["authenticated"] = True
+            session["user"] = username if multi_user else ""
             session.permanent = True
             # Always redirect to dashboard — avoids bare-path redirect issues
             # when running behind a reverse proxy subpath (e.g. /media/)
             return redirect(url_for("dashboard"))
-        error = "Incorrect password. Try again."
+        # Deliberately doesn't say which half was wrong.
-    # If no password is set, auto-login (dev mode)
+        error = ("Incorrect username or password." if multi_user
-    if not get_active_password():
+                 else "Incorrect password. Try again.")
+    # If nothing is configured at all, auto-login (dev mode)
+    if not multi_user and not get_active_password():
         session["authenticated"] = True
         return redirect(url_for("dashboard"))
-    return render_template("login.html", error=error)
+    return render_template("login.html", error=error, multi_user=multi_user)
 
 
 @app.route("/logout")
@@ -1404,13 +1465,26 @@ def api_change_password():
     confirm = data.get("confirm", "")
     if not current or not new_pw or not confirm:
         return jsonify({"error": "All fields are required"}), 400
-    if _hash_password(current) != _hash_password(get_active_password()):
-        return jsonify({"error": "Current password is incorrect"}), 403
     if new_pw != confirm:
         return jsonify({"error": "New passwords do not match"}), 400
     if len(new_pw) < 6:
         return jsonify({"error": "Password must be at least 6 characters"}), 400
-    # Persist to settings.json and update runtime variable
+
+    users = load_users()
+    if users:
+        # Multi-user: change only the signed-in account's own password.
+        me = session.get("user", "")
+        if me not in users or not verify_credentials(me, current):
+            return jsonify({"error": "Current password is incorrect"}), 403
+        users[me] = generate_password_hash(new_pw, method=PASSWORD_HASH_METHOD)
+        save_settings({"users": users})
+        # No _runtime_password here: load_users() re-reads settings.json on
+        # every check, so the change is live in every worker immediately.
+        return jsonify({"success": True})
+
+    if not verify_credentials("", current):
+        return jsonify({"error": "Current password is incorrect"}), 403
+    # Legacy single-password install: persist and update the runtime value.
     save_settings({"login_password": new_pw})
     _runtime_password = new_pw
     return jsonify({"success": True})

manage_users.py

@@ -0,0 +1,136 @@
+#!/usr/bin/env python3
+"""Add, list and remove Media Centre dashboard accounts.
+
+Passwords are prompted for interactively (never echoed, never taken as a
+command-line argument, so they don't land in shell history) and only ever
+stored as a salted pbkdf2 hash in settings.json. Nothing here writes a
+plaintext password anywhere.
+
+Run it inside the container, where Werkzeug and the real settings.json are:
+
+    docker exec -it arr-summary python3 manage_users.py list
+    docker exec -it arr-summary python3 manage_users.py add <username>
+    docker exec -it arr-summary python3 manage_users.py passwd <username>
+    docker exec -it arr-summary python3 manage_users.py remove <username>
+
+The first `add` switches the dashboard from its single shared password to
+per-user logins. Until then the old LOGIN_PASSWORD keeps working, so you
+can't lock yourself out by deploying this.
+"""
+
+import sys
+import getpass
+
+from app import (
+    SETTINGS_FILE,
+    PASSWORD_HASH_METHOD,
+    save_settings,
+    load_users,
+    generate_password_hash,
+)
+
+MIN_LEN = 6
+
+
+def _prompt_new_password(username):
+    """Ask twice, confirm they match, never echo. None if aborted."""
+    pw = getpass.getpass(f"New password for {username!r}: ")
+    if not pw:
+        print("Aborted: empty password.", file=sys.stderr)
+        return None
+    if len(pw) < MIN_LEN:
+        print(f"Aborted: must be at least {MIN_LEN} characters.", file=sys.stderr)
+        return None
+    if pw != getpass.getpass("Confirm: "):
+        print("Aborted: passwords don't match.", file=sys.stderr)
+        return None
+    return pw
+
+
+def cmd_list(_args):
+    users = load_users()
+    if not users:
+        print("No accounts configured — the dashboard is still using the")
+        print("single shared password (LOGIN_PASSWORD / settings.json).")
+        return 0
+    print(f"{len(users)} account(s) in {SETTINGS_FILE}:")
+    for name in sorted(users):
+        print(f"  {name}")
+    return 0
+
+
+def _set_password(username, require_existing):
+    users = load_users()
+    exists = username in users
+    if require_existing and not exists:
+        print(f"No such account: {username!r}. Use `add` to create it.", file=sys.stderr)
+        return 1
+    if not require_existing and exists:
+        print(f"Account {username!r} already exists. Use `passwd` to change it.",
+              file=sys.stderr)
+        return 1
+
+    pw = _prompt_new_password(username)
+    if pw is None:
+        return 1
+
+    users[username] = generate_password_hash(pw, method=PASSWORD_HASH_METHOD)
+    save_settings({"users": users})
+    print(f"{'Updated' if exists else 'Created'} {username!r} in {SETTINGS_FILE}.")
+    if not exists and len(users) == 1:
+        print()
+        print("This is the first account, so the dashboard has just switched to")
+        print("per-user logins. The old shared password no longer signs in —")
+        print("make sure you can log in as this user before closing this shell.")
+    return 0
+
+
+def cmd_add(args):
+    if not args:
+        print("Usage: manage_users.py add <username>", file=sys.stderr)
+        return 2
+    return _set_password(args[0].strip(), require_existing=False)
+
+
+def cmd_passwd(args):
+    if not args:
+        print("Usage: manage_users.py passwd <username>", file=sys.stderr)
+        return 2
+    return _set_password(args[0].strip(), require_existing=True)
+
+
+def cmd_remove(args):
+    if not args:
+        print("Usage: manage_users.py remove <username>", file=sys.stderr)
+        return 2
+    username = args[0].strip()
+    users = load_users()
+    if username not in users:
+        print(f"No such account: {username!r}", file=sys.stderr)
+        return 1
+    if len(users) == 1:
+        print("Refusing to remove the last account — that would drop the dashboard",
+              file=sys.stderr)
+        print("back to the shared password, which is probably not what you meant.",
+              file=sys.stderr)
+        print("Add another account first, or clear `users` from settings.json by hand.",
+              file=sys.stderr)
+        return 1
+    del users[username]
+    save_settings({"users": users})
+    print(f"Removed {username!r}. {len(users)} account(s) remain.")
+    return 0
+
+
+COMMANDS = {"list": cmd_list, "add": cmd_add, "passwd": cmd_passwd, "remove": cmd_remove}
+
+
+def main(argv):
+    if len(argv) < 2 or argv[1] not in COMMANDS:
+        print(__doc__.strip())
+        return 2
+    return COMMANDS[argv[1]](argv[2:])
+
+
+if __name__ == "__main__":
+    sys.exit(main(sys.argv))

static/css/login.css

@@ -54,6 +54,9 @@ input {
 }
 input:focus { border-color: var(--accent); }
 input::placeholder { color: var(--text-3); }
+/* Second field in a stacked pair (username above password) needs the gap
+   the single-field form never had. */
+label.stacked { margin-top: 1rem; }
 
 .error-msg {
   background: var(--surface-2);

templates/login.html

@@ -29,9 +29,19 @@
       {% endif %}
 
       <form method="POST" action="{{ url_for('login', next=request.args.get('next', '')) }}">
-        <label for="password">Password</label>
+        {# The username field only appears once accounts exist in
+           settings.json. A single-password install never sees a box it
+           would have to leave blank. #}
+        {% if multi_user %}
+        <label for="username">Username</label>
+        <input type="text" id="username" name="username"
+               placeholder="Enter username" autofocus autocomplete="username"
+               autocapitalize="none" autocorrect="off" spellcheck="false">
+        {% endif %}
+        <label for="password"{% if multi_user %} class="stacked"{% endif %}>Password</label>
         <input type="password" id="password" name="password"
-               placeholder="Enter password" autofocus autocomplete="current-password">
+               placeholder="Enter password"{% if not multi_user %} autofocus{% endif %}
+               autocomplete="current-password">
         <button type="submit">Sign in</button>
       </form>
     </div>