feat: security hardening — SSRF guard, template sandbox timeout, webhook log prune, auth & backup polish

- Add outbound URL validation (SSRF) for webhook/Discord/Slack/ntfy/Matrix dispatch
- Template renderer: input/output caps and thread-based render timeout
- Webhook log filter: strip Authorization/signature/token-like headers; atomic prune
- Auth/JWT/backup/config tightening; misc frontend UX fixes

packages/server/src/notify_bridge_server/services/backup_service.py

@@ -34,6 +34,44 @@ _LOGGER = logging.getLogger(__name__)
 # Fields to skip when serializing TrackingConfig into the generic `fields` dict
 _TRACKING_SKIP = frozenset(("id", "user_id", "provider_type", "name", "icon", "created_at"))
 
+# Import-time config hardening limits
+_MAX_CONFIG_DEPTH = 6
+_MAX_CONFIG_KEYS = 200
+_MAX_STRING_LEN = 8192
+
+
+def _sanitize_config(value: Any, depth: int = 0) -> Any:
+    """Clamp imported config values to safe shapes before persistence.
+
+    Rejects anything that is not a JSON-compatible primitive/container, truncates
+    over-long strings, and caps dict/list sizes. Returns a defensively-copied
+    structure; the caller should never see attacker-controlled references.
+    """
+    if depth > _MAX_CONFIG_DEPTH:
+        raise ValueError("Config nesting exceeds maximum depth")
+    if value is None or isinstance(value, bool):
+        return value
+    if isinstance(value, (int, float)):
+        return value
+    if isinstance(value, str):
+        return value[:_MAX_STRING_LEN]
+    if isinstance(value, list):
+        if len(value) > _MAX_CONFIG_KEYS:
+            raise ValueError("Config list exceeds maximum length")
+        return [_sanitize_config(v, depth + 1) for v in value]
+    if isinstance(value, dict):
+        if len(value) > _MAX_CONFIG_KEYS:
+            raise ValueError("Config dict exceeds maximum key count")
+        cleaned: dict[str, Any] = {}
+        for k, v in value.items():
+            if not isinstance(k, str):
+                raise ValueError("Config keys must be strings")
+            if len(k) > 128:
+                raise ValueError(f"Config key too long: {k[:40]}...")
+            cleaned[k] = _sanitize_config(v, depth + 1)
+        return cleaned
+    raise ValueError(f"Unsupported config value type: {type(value).__name__}")
+
 
 # ---------------------------------------------------------------------------
 # Export
@@ -530,9 +568,14 @@ async def import_backup(
             )
             if name is None:
                 continue
+            try:
+                safe_cfg = _sanitize_config(p.config or {})
+            except ValueError as exc:
+                result.warnings.append(f"Skipped provider '{p.name}': {exc}")
+                continue
             new_p = ServiceProvider(
                 user_id=user_id, type=p.type, name=name,
-                icon=p.icon, config=p.config,
+                icon=p.icon, config=safe_cfg,
             )
             session.add(new_p)
             await session.flush()
@@ -635,17 +678,27 @@ async def import_backup(
             )
             if name is None:
                 continue
+            try:
+                safe_tgt_cfg = _sanitize_config(tgt.config or {})
+            except ValueError as exc:
+                result.warnings.append(f"Skipped target '{tgt.name}': {exc}")
+                continue
             new_tgt = NotificationTarget(
                 user_id=user_id, type=tgt.type, name=name,
-                icon=tgt.icon, config=tgt.config,
+                icon=tgt.icon, config=safe_tgt_cfg,
                 chat_action=tgt.chat_action,
             )
             session.add(new_tgt)
             await session.flush()
             id_map["targets"][tgt.id] = new_tgt.id
             for r in tgt.receivers:
+                try:
+                    safe_r_cfg = _sanitize_config(r.config or {})
+                except ValueError as exc:
+                    result.warnings.append(f"Skipped receiver in '{tgt.name}': {exc}")
+                    continue
                 session.add(TargetReceiver(
-                    target_id=new_tgt.id, name=r.name, config=r.config,
+                    target_id=new_tgt.id, name=r.name, config=safe_r_cfg,
                     receiver_key=r.receiver_key, locale=r.locale,
                     enabled=r.enabled,
                 ))