fix(security): F03 (Astra P1) — Sitzungswiderruf in beiden Session-Stores durchsetzen

Vorher (Astra-Finding): Widerruf war inkonsistent ueber vier Pfade:
- Deaktivierung invalidierte nur den Berechtigungscache — Sessions
  liefen bis TTL (8h) weiter
- Loeschung invalidierte GAR NICHTS
- Passwortwechsel loeschte nur Redis-Sessions — PostgreSQL-Fallback-
  Sessions ueberlebten jeden Redis-Ausfall
- Fehlende UserTenant-Mitgliedschaft wurde durchgewinkt statt
  abgewiesen

Fix:
- Neuer zentraler Helfer revoke_user_sessions_all_stores (app/core/auth.py):
  Redis-Sessions loeschen UND PostgreSQL-Fallback-Sessions per
  expires_at=now() ablaufen lassen (Audit-Trail bleibt, Zugriff stirbt
  sofort — der DB-Fallback-Pfad prueft expires_at bereits)
- Alle 4 Widerrufsstellen verdrahtet: Deaktivierung + Loeschung
  (routes/users.py), Passwortwechsel (user_service.py), Passwort-Reset
  (auth_service.py)
- Membership-Check in get_current_user fail-closed: None (fehlende
  Mitgliedschaft) wird abgewiesen statt durchgelassen

Abnahme (Astra): Deaktivierung, Austritt und Passwortwechsel wirken
unmittelbar — auch bei Redis-Ausfall (Unit-Test beweist die
DB-Fallback-Abgelaufen-Rejection).

Tests: test_s1_security_guards.py 10/10 (3 neue F03-Tests) +
test_auth.py 11/11 + ruff clean.

app/core/auth.py

@@ -117,6 +117,55 @@ async def revoke_user_redis_sessions(user_id: str | uuid.UUID) -> int:
         return 0
 
 
+async def revoke_user_sessions_all_stores(user_id: str | uuid.UUID) -> None:
+    """F03 (Astra): revoke ALL sessions for a user in BOTH session stores.
+
+    Deactivation, deletion and password changes must take effect immediately —
+    including when Redis is down and requests fall back to the PostgreSQL
+    sessions table.
+
+    1. Redis runtime sessions are deleted (revoke_user_redis_sessions).
+    2. PostgreSQL session records are EXPIRED by setting ``expires_at = now()``
+       (not deleted — they stay as audit trail). The DB fallback path in
+       ``get_session_data`` rejects sessions whose ``expires_at`` is past.
+
+    Never raises — best-effort per store, but errors are logged loudly.
+    """
+    # 1. Redis runtime sessions
+    await revoke_user_redis_sessions(user_id)
+
+    # 2. PostgreSQL fallback sessions — expire instead of delete (audit trail)
+    try:
+        from datetime import UTC, datetime
+
+        from sqlalchemy import update
+
+        from app.core.db import get_session_factory
+        from app.models.session import Session as SessionModel
+
+        uid = user_id if isinstance(user_id, uuid.UUID) else uuid.UUID(str(user_id))
+        factory = get_session_factory()
+        async with factory() as db:
+            result = await db.execute(
+                update(SessionModel)
+                .where(
+                    SessionModel.user_id == uid,
+                    SessionModel.expires_at > datetime.now(UTC),
+                )
+                .values(expires_at=datetime.now(UTC))
+            )
+            await db.commit()
+            if result.rowcount:
+                logger.info(
+                    "F03: expired %d PostgreSQL fallback sessions for user %s",
+                    result.rowcount, uid,
+                )
+    except Exception:
+        logger.warning(
+            "F03: failed to expire PostgreSQL sessions for user %s", user_id, exc_info=True
+        )
+
+
 def hash_token(token: str) -> str:
     """SHA-256 hash a token for storage."""
     return hashlib.sha256(token.encode()).hexdigest()

app/deps.py

@@ -130,10 +130,20 @@ async def get_current_user(
     membership_row = membership_q.first()
     membership_status = membership_row[0] if membership_row else None
     role_id = membership_row[1] if membership_row else None
-    if membership_status is not None and membership_status != "active":
+    # F03 (Astra): a MISSING tenant membership must be rejected, not waved
+    # through. Previously `is not None` let membership-less sessions access
+    # the tenant's data via the RLS context set above.
+    if membership_status is None or membership_status != "active":
         raise HTTPException(
             status_code=status.HTTP_403_FORBIDDEN,
-            detail={"detail": f"Mitgliedschaft ist {membership_status}, Zugriff verweigert", "code": "membership_suspended"},
+            detail={
+                "detail": (
+                    f"Mitgliedschaft ist {membership_status}, Zugriff verweigert"
+                    if membership_status
+                    else "Keine aktive Mandanten-Mitgliedschaft, Zugriff verweigert"
+                ),
+                "code": "membership_suspended",
+            },
         )
 
     # Cache user principals for this request — avoids N+1 queries in visibility.py

app/routes/users.py

@@ -339,6 +339,15 @@ async def update_user(
         except Exception:
             pass  # Best-effort — don't fail the update if Redis is down
 
+    # F03 (Astra): deactivation must take effect IMMEDIATELY in BOTH session
+    # stores (Redis runtime + PostgreSQL fallback) — not just the permission
+    # cache. Otherwise a deactivated user keeps working until the session TTL
+    # (8h) expires, and DB-fallback sessions survive Redis outages entirely.
+    if body.is_active is False:
+        from app.core.auth import revoke_user_sessions_all_stores
+
+        await revoke_user_sessions_all_stores(uid)
+
     return {
         "id": str(user.id),
         "email": user.email,
@@ -379,6 +388,12 @@ async def delete_user(
     if not success:
         raise HTTPException(404, detail={"detail": "User not found", "code": "not_found"})
 
+    # F03 (Astra): deletion must revoke all sessions immediately — in BOTH
+    # stores (Redis runtime + PostgreSQL fallback).
+    from app.core.auth import revoke_user_sessions_all_stores
+
+    await revoke_user_sessions_all_stores(uid)
+
     await log_audit(
         db,
         tenant_id,

app/services/auth_service.py

@@ -328,11 +328,12 @@ class AuthService:
         reset_token.used_at = datetime.now(UTC)
         await db.flush()
 
-        # Invalidate all active Redis sessions for this user
-        # (shared helper — same mechanism as the profile/admin change path)
-        from app.core.auth import revoke_user_redis_sessions
+        # Invalidate all active sessions for this user — in BOTH stores
+        # (F03/Astra: PostgreSQL fallback sessions must not survive a Redis
+        # outage after a password change; shared helper for all password paths)
+        from app.core.auth import revoke_user_sessions_all_stores
 
-        await revoke_user_redis_sessions(user.id)
+        await revoke_user_sessions_all_stores(user.id)
 
         # Audit log entry for password reset — use separate API session (crm_api)
         # to avoid requiring audit_log INSERT grants on crm_auth

app/services/user_service.py

@@ -204,10 +204,12 @@ class UserService:
 
         # G2: after a profile/admin password change, kill all other sessions —
         # a stolen or lingering session must not survive the change.
+        # F03 (Astra): revoke in BOTH stores — PostgreSQL fallback sessions
+        # must not survive a Redis outage after a password change.
         if new_password is not None:
-            from app.core.auth import revoke_user_redis_sessions
+            from app.core.auth import revoke_user_sessions_all_stores
 
-            await revoke_user_redis_sessions(user.id)
+            await revoke_user_sessions_all_stores(user.id)
 
         return user, user_tenant