Admin kann Nutzer-Konto übernehmen (Impersonation) mit Rückwechsel

- sessions.impersonator_id: Admin-Session behält Token, schaltet user_id
  aufs Ziel, Admin bleibt in impersonator_id gespeichert (Stack, keine
  Verschachtelung). uid()/Config/Dateien laufen als Ziel-Nutzer.
- Admin sieht in /admin pro Nutzer "Anmelden als"; Bestätigungsdialog.
- Dauerhaftes amber Banner im Header mit "Zurück zum Admin" (POST, kein JS
  nötig) erscheint auf jeder Seite während Impersonation.
- requireAdmin verweigert während Impersonation -> keine Admin-Aktionen als
  fremder Nutzer; Stop-Route prüft impersonator_id (kein Escalation-Pfad für
  Normalnutzer). Selbst-Imitation blockiert.
- audit_log-Tabelle protokolliert Start/Stop persistent; Admin-Seite zeigt
  Audit-Liste (/admin/audit/impersonations).
- Migration: idempotentes ALTER ADD COLUMN impersonator_id fuer Bestand.

Co-Authored-By: Claude <noreply@anthropic.com>
This commit is contained in:
2026-07-14 02:17:50 +02:00
co-authored by Claude
parent fd1db3970f
commit e0733666ae
4 changed files with 225 additions and 6 deletions
+6
View File
@@ -79,6 +79,12 @@ async function runMigration({ db, dbAll, dbGet, dbRun }) {
)
`);
await exec('CREATE INDEX IF NOT EXISTS idx_sessions_user ON sessions(user_id)');
// Impersonation support: the admin's session keeps its token but switches
// user_id to the target, storing the original admin in impersonator_id so the
// admin can switch back. Added after the fact for existing installs.
if (!(await hasColumn('sessions', 'impersonator_id'))) {
await exec('ALTER TABLE sessions ADD COLUMN impersonator_id INTEGER');
}
// 2. Ensure admin user (idempotent) -----------------------------------
let admin = await dbGet('SELECT id, password_hash FROM users WHERE username = ?', [ADMIN_USERNAME]);
+138 -6
View File
@@ -158,9 +158,16 @@ app.set('views', path.join(__dirname, 'views'));
app.use(async (req, res, next) => {
try {
const cookies = parseCookies(req.headers.cookie);
const user = await loadSessionUser(cookies[SESSION_COOKIE]);
const token = cookies[SESSION_COOKIE];
const user = await loadSessionUser(token);
req.user = user;
req.sessionToken = token;
res.locals.user = user;
// impersonator is set when an admin is acting as another user; the header
// shows a banner and the "switch back" action uses it.
const impersonator = user && user.impersonator ? user.impersonator : null;
req.impersonator = impersonator;
res.locals.impersonator = impersonator;
// The header highlights the section you are in; it needs the current path.
res.locals.pfad = req.path;
// Warm this user's cfg rows before anything reads them: config.get() is
@@ -681,12 +688,22 @@ async function destroySession(token) {
// enforces the server-side absolute session expiry: a cookie is only valid for
// SESSION_MAX_AGE after the last activity, regardless of the client-side
// maxAge (which a client can tamper with). Expired rows are deleted.
//
// When the session is an impersonation (an admin "logging in as" a user), the
// returned user is the *target*; `impersonator` carries the original admin so
// the app can show a banner and offer a "switch back" action. While
// impersonating, the effective user has no admin rights (see requireAdmin) —
// the admin is debugging the user's account, not escalating.
async function loadSessionUser(token) {
if (!token) return null;
const row = await dbGet(
`SELECT u.id AS id, u.username AS username, u.is_admin AS is_admin,
s.created_at AS created_at, s.last_seen AS last_seen
FROM sessions s JOIN users u ON u.id = s.user_id
s.created_at AS created_at, s.last_seen AS last_seen,
s.impersonator_id AS impersonator_id,
i.username AS impersonator_username, i.is_admin AS impersonator_is_admin
FROM sessions s
JOIN users u ON u.id = s.user_id
LEFT JOIN users i ON i.id = s.impersonator_id
WHERE s.token = ?`,
[token]
);
@@ -698,7 +715,11 @@ async function loadSessionUser(token) {
return null;
}
await dbRun('UPDATE sessions SET last_seen = CURRENT_TIMESTAMP WHERE token = ?', [token]).catch(() => {});
return { id: row.id, username: row.username, is_admin: !!row.is_admin };
const user = { id: row.id, username: row.username, is_admin: !!row.is_admin };
if (row.impersonator_id) {
user.impersonator = { id: row.impersonator_id, username: row.impersonator_username, is_admin: !!row.impersonator_is_admin };
}
return user;
}
// Find a user by username + password (login check). Returns the user object or null.
@@ -1161,10 +1182,27 @@ async function initializeDatabase() {
user_id INTEGER NOT NULL,
created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
last_seen DATETIME DEFAULT CURRENT_TIMESTAMP,
FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
impersonator_id INTEGER,
FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
FOREIGN KEY (impersonator_id) REFERENCES users(id) ON DELETE SET NULL
)
`);
await exec('CREATE INDEX IF NOT EXISTS idx_sessions_user ON sessions(user_id)');
// Audit trail for admin actions that act on another user's account (today:
// impersonation start/stop). Persistent so a later review can reconstruct who
// acted as whom and when — a plain console.log would not survive a restart.
await exec(`
CREATE TABLE IF NOT EXISTS audit_log (
id INTEGER PRIMARY KEY AUTOINCREMENT,
actor_user_id INTEGER,
target_user_id INTEGER,
action TEXT NOT NULL,
created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
FOREIGN KEY (actor_user_id) REFERENCES users(id) ON DELETE SET NULL,
FOREIGN KEY (target_user_id) REFERENCES users(id) ON DELETE SET NULL
)
`);
await exec('CREATE INDEX IF NOT EXISTS idx_audit_created ON audit_log(created_at)');
// Upgrade legacy single-user installs BEFORE the per-user CREATE/INDEX
// statements below: the migration adds the user_id column to every existing
@@ -3473,7 +3511,10 @@ initializeDatabase().then(async () => {
// alle seine Daten (Bewerbungen, E-Mails, Termine, Chat, Dateien liegen in
// data/<dir>/<userId>/ und müssen separat entfernt werden — siehe unten).
function requireAdmin(req, res, next) {
if (req.user && req.user.is_admin) return next();
// Admin rights are suspended while impersonating another user: the admin is
// reviewing that user's account, not exercising admin powers. This also
// keeps the impersonated session from reaching admin endpoints at all.
if (req.user && req.user.is_admin && !req.impersonator) return next();
if (req.path.startsWith('/admin/') || req.xhr || (req.get('accept') || '').includes('application/json')) {
return res.status(403).send('Zugriff verweigert nur für Administratoren.');
}
@@ -3552,6 +3593,97 @@ initializeDatabase().then(async () => {
}
});
// --- Impersonation: admin "logs in as" a user --------------------------
// Best practice (Django/Flask-impersonate style): the admin's own session
// keeps its cookie token, but its user_id switches to the target and the
// original admin is preserved in sessions.impersonator_id. Everything the app
// does (DB queries via uid(), per-user config, file dirs) then runs as the
// target — the admin sees exactly the user's account. Admin rights are
// suspended while impersonating (requireAdmin), and a banner + "switch back"
// action are always one click away. Every start/stop is recorded in audit_log.
async function auditLog(actorId, targetId, action) {
await dbRun(
'INSERT INTO audit_log (actor_user_id, target_user_id, action) VALUES (?, ?, ?)',
[actorId || null, targetId || null, action]
).catch((e) => console.error('audit_log write failed:', e.message));
}
// Start impersonating a user. Admin-only, and never while already
// impersonating (no nesting — switch back first).
app.post('/admin/users/:id/impersonate', requireAdmin, async (req, res) => {
try {
const targetId = Number(req.params.id);
if (!targetId || targetId === Number(req.user.id)) {
return res.status(400).send('Man kann sich nicht selbst imitieren.');
}
const target = await dbGet('SELECT id, username FROM users WHERE id = ?', [targetId]);
if (!target) return res.status(404).send('Benutzer nicht gefunden.');
const token = req.sessionToken;
if (!token) return res.status(400).send('Keine Sitzung.');
await dbRun(
'UPDATE sessions SET user_id = ?, impersonator_id = ?, last_seen = CURRENT_TIMESTAMP WHERE token = ?',
[target.id, req.user.id, token]
);
await auditLog(req.user.id, target.id, `impersonate_start → ${target.username}`);
console.log(`Impersonation: Admin #${req.user.id} (${req.user.username}) → User #${target.id} (${target.username})`);
res.redirect('/');
} catch (error) {
console.error('Admin impersonate error:', error);
res.status(500).send('Serverfehler');
}
});
// Switch back to the original admin. This is intentionally NOT requireAdmin:
// it runs while impersonating, when req.user is the target (non-admin). The
// guard is the session's impersonator_id — only an actual impersonation can
// stop one, so a normal user session (impersonator_id NULL) cannot use it.
app.post('/admin/impersonate/stop', async (req, res) => {
try {
const token = req.sessionToken;
if (!token) return res.redirect('/');
const row = await dbGet(
'SELECT user_id, impersonator_id FROM sessions WHERE token = ?',
[token]
);
if (!row || !row.impersonator_id) {
return res.status(403).send('Keine aktive Impersonation.');
}
const adminId = row.impersonator_id;
const targetId = row.user_id;
await dbRun(
'UPDATE sessions SET user_id = ?, impersonator_id = NULL, last_seen = CURRENT_TIMESTAMP WHERE token = ?',
[adminId, token]
);
await auditLog(adminId, targetId, 'impersonate_stop');
console.log(`Impersonation: Admin #${adminId} switched back from User #${targetId}`);
res.redirect('/admin');
} catch (error) {
console.error('Admin impersonate stop error:', error);
res.status(500).send('Serverfehler');
}
});
// Recent impersonation audit entries for the admin dashboard.
app.get('/admin/audit/impersonations', requireAdmin, async (req, res) => {
try {
const rows = await dbAll(
`SELECT a.action, a.created_at,
au.username AS actor, tu.username AS target
FROM audit_log a
LEFT JOIN users au ON au.id = a.actor_user_id
LEFT JOIN users tu ON tu.id = a.target_user_id
WHERE a.action LIKE 'impersonate_%'
ORDER BY a.created_at DESC
LIMIT 25`
);
res.json({ items: rows });
} catch (error) {
console.error('Audit list error:', error);
res.status(500).json({ error: 'Serverfehler' });
}
});
// ----- Conversational KI-Chat (Ollama, streaming) -----
// Gated behind OLLAMA_API_KEY. Threads + messages persist in SQLite; the
// assistant answer is streamed back via Server-Sent Events.
+58
View File
@@ -77,6 +77,13 @@
<a href="/jobsuche?user=<%= u.id %>"
class="text-sm text-blue-600 dark:text-blue-400 hover:underline mr-3"
title="Suchprofil und Zeitplan dieses Benutzers verwalten">Jobsuche</a>
<% if (u.id !== currentUserId) { %>
<form method="POST" action="/admin/users/<%= u.id %>/impersonate" class="inline"
onsubmit="return confirm('Als „<%= u.username %>“ anmelden? Du siehst dann dessen Konto. Admin-Rechte sind dabei pausiert; über das Banner oben kannst du zurückwechseln.');">
<button type="submit" class="text-sm text-emerald-600 dark:text-emerald-400 hover:underline mr-3"
title="Dieses Konto übernehmen (Impersonation)">Anmelden als</button>
</form>
<% } %>
<button type="button"
onclick="document.getElementById('resetForm<%= u.id %>').classList.toggle('hidden')"
class="text-sm text-blue-600 dark:text-blue-400 hover:underline mr-3">
@@ -109,6 +116,57 @@
</table>
</div>
</div>
<!-- Impersonations-Audit: wer hat als wen gehandelt, wann -->
<div class="bg-white dark:bg-gray-800 rounded-lg shadow-md p-6 mt-8">
<h3 class="text-lg font-semibold mb-1">Impersonationen (Audit)</h3>
<p class="text-sm text-gray-500 dark:text-gray-400 mb-4">Nachvollziehbar protokolliert: jeder Wechsel auf ein anderes Konto und jeder Rückwechsel.</p>
<div class="overflow-x-auto">
<table class="w-full text-sm">
<thead>
<tr class="text-left text-gray-500 dark:text-gray-400 border-b border-gray-200 dark:border-gray-700">
<th class="py-2 pr-4 font-medium">Admin</th>
<th class="py-2 pr-4 font-medium">Aktion</th>
<th class="py-2 pr-4 font-medium">Zeit</th>
</tr>
</thead>
<tbody id="auditBody" class="divide-y divide-gray-100 dark:divide-gray-700">
<tr><td colspan="3" class="py-4 text-gray-400 dark:text-gray-500">… wird geladen</td></tr>
</tbody>
</table>
</div>
</div>
</main>
<script>
(function () {
function esc(s) { var d = document.createElement('div'); d.textContent = s == null ? '' : String(s); return d.innerHTML; }
fetch('/admin/audit/impersonations', { cache: 'no-store' })
.then(function (r) { return r.json(); })
.then(function (d) {
var body = document.getElementById('auditBody');
var items = (d && d.items) || [];
if (!items.length) {
body.innerHTML = '<tr><td colspan="3" class="py-4 text-gray-400 dark:text-gray-500">Keine Impersonationen protokolliert.</td></tr>';
return;
}
body.innerHTML = items.map(function (it) {
var isStop = /stop/.test(it.action);
var badge = isStop
? '<span class="inline-flex px-2 py-0.5 rounded-full text-xs font-medium bg-gray-100 text-gray-600 dark:bg-gray-700 dark:text-gray-300">Rückwechsel</span>'
: '<span class="inline-flex px-2 py-0.5 rounded-full text-xs font-medium bg-emerald-100 text-emerald-700 dark:bg-emerald-900/40 dark:text-emerald-300">Anmeldung als</span>';
var ziel = isStop ? '' : ' <span class="text-gray-700 dark:text-gray-300">' + esc(it.action.replace(/^impersonate_start\s*→\s*/, '')) + '</span>';
return '<tr>'
+ '<td class="py-2 pr-4 font-medium text-gray-800 dark:text-gray-100">' + esc(it.actor || '?') + '</td>'
+ '<td class="py-2 pr-4">' + badge + ziel + '</td>'
+ '<td class="py-2 pr-4 text-gray-500 dark:text-gray-400">' + esc(it.created_at) + '</td>'
+ '</tr>';
}).join('');
})
.catch(function () {
document.getElementById('auditBody').innerHTML = '<tr><td colspan="3" class="py-4 text-gray-400 dark:text-gray-500">Audit konnte nicht geladen werden.</td></tr>';
});
})();
</script>
</body>
</html>
+23
View File
@@ -212,6 +212,29 @@
</div>
</div>
<% if (typeof impersonator !== 'undefined' && impersonator) { %>
<!-- Impersonation banner: unmistakable and always present while an admin is
acting as another user. The "switch back" form is a real POST so it works
without JS; admin rights are suspended until the switch back. -->
<div class="border-t border-amber-300/60 bg-amber-50/95 backdrop-blur-md dark:border-amber-400/20 dark:bg-amber-500/10">
<div class="container mx-auto flex flex-wrap items-center gap-x-3 gap-y-1 px-4 py-2 text-sm text-amber-800 dark:text-amber-200">
<svg class="h-4 w-4 shrink-0" fill="none" stroke="currentColor" stroke-width="2" viewBox="0 0 24 24">
<path stroke-linecap="round" stroke-linejoin="round" d="M16 7a4 4 0 11-8 0 4 4 0 018 0zM12 14v7m-4-4h8"></path>
</svg>
<span class="font-medium">Impersonation aktiv:</span>
<span>du handelst als <strong class="font-semibold"><%= user.username %></strong> (eingeloggt durch <strong class="font-semibold"><%= impersonator.username %></strong>). Admin-Aktionen sind pausiert.</span>
<form method="POST" action="/admin/impersonate/stop" class="ml-auto">
<button type="submit" class="inline-flex items-center gap-1.5 rounded-md bg-amber-600 hover:bg-amber-700 px-3 py-1.5 text-xs font-medium text-white transition-colors">
<svg class="h-3.5 w-3.5" fill="none" stroke="currentColor" stroke-width="2.5" viewBox="0 0 24 24">
<path stroke-linecap="round" stroke-linejoin="round" d="M10 19l-7-7m0 0l7-7m-7 7h18"></path>
</svg>
Zurück zum Admin
</button>
</form>
</div>
</div>
<% } %>
<!-- Mobile navigation: the same structure, spelled out. The old header just
dropped the labels and left seven unlabelled icons. -->
<div id="mobileNav" class="hidden border-t border-gray-200/80 bg-gray-50 lg:hidden dark:border-white/5 dark:bg-gray-900">