Harden OpenWrt JSON parsing

services/openwrt.py

@@ -124,16 +124,28 @@ def _extract_ifnames(wireless: dict[str, Any]) -> list[str]:
     return ifnames
 
 
-def _parse_hostapd_clients(raw: str, ifname: str) -> list[str]:
+def _safe_json_load(raw: str) -> Any | None:
+    if not raw:
+        return None
     try:
-        payload = json.loads(raw)
+        return json.loads(raw)
     except json.JSONDecodeError:
+        start = raw.find("{")
+        end = raw.rfind("}")
+        if start == -1 or end == -1 or end <= start:
+            return None
+        try:
+            return json.loads(raw[start : end + 1])
+        except json.JSONDecodeError:
+            return None
+
+
+def _parse_hostapd_clients(payload: Any, ifname: str) -> list[str]:
+    if not isinstance(payload, dict):
         return []
-    data = payload.get("clients") if isinstance(payload, dict) else None
+    data = payload.get("clients")
     if isinstance(data, dict):
         items = data.items()
-    elif isinstance(payload, dict):
-        items = payload.items()
     else:
         return []
     clients: list[str] = []
@@ -229,22 +241,13 @@ async def get_openwrt_status(cfg: dict[str, Any]) -> str:
     wireless = None
     leases = None
     leases_fallback = ""
-    try:
-        sys_info = json.loads(parts[0])
-    except json.JSONDecodeError:
+    sys_info = _safe_json_load(parts[0])
+    if sys_info is None:
         sys_info = None
-    try:
-        wan_status = json.loads(parts[1])
-    except json.JSONDecodeError:
-        wan_status = {}
-    try:
-        wireless = json.loads(parts[2])
-    except json.JSONDecodeError:
-        wireless = {}
-    try:
-        leases = json.loads(parts[3])
-    except json.JSONDecodeError:
-        leases = None
+    wan_status = _safe_json_load(parts[1]) or {}
+    wireless = _safe_json_load(parts[2]) or {}
+    leases = _safe_json_load(parts[3])
+    if leases is None:
         leases_fallback = parts[3]
 
     if isinstance(sys_info, dict):
@@ -270,8 +273,9 @@ async def get_openwrt_status(cfg: dict[str, Any]) -> str:
             rc2, out2 = await run_cmd_full(cmd_clients, timeout=timeout_sec + 15)
             if rc2 == 124:
                 return f"⚠️ OpenWrt SSH error (wifi clients {ifname}): timeout"
-            if rc2 == 0 and out2.strip():
-                wifi_clients.extend(_parse_hostapd_clients(out2.strip(), ifname))
+            payload = _safe_json_load(out2)
+            if payload:
+                wifi_clients.extend(_parse_hostapd_clients(payload, ifname))
 
     if leases:
         leases_list = _extract_leases(leases)