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Fix json buffer guard #3743

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Fix json buffer guard #3743

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11 changes: 7 additions & 4 deletions wled00/json.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1017,7 +1017,10 @@ void serializeModeNames(JsonArray arr)
// Global buffer locking response helper class
class GlobalBufferAsyncJsonResponse: public JSONBufferGuard, public AsyncJsonResponse {
public:
inline GlobalBufferAsyncJsonResponse(bool isArray) : JSONBufferGuard(17), AsyncJsonResponse(&doc, isArray) {};
// This is safe if and only if the guard owns the lock.
inline GlobalBufferAsyncJsonResponse(JSONBufferGuard&& guard, bool isArray) : JSONBufferGuard(std::move(guard)), AsyncJsonResponse(owns_lock() ? &doc : nullptr, isArray) {
assert(owns_lock());
};
virtual ~GlobalBufferAsyncJsonResponse() {};

// Other members are inherited
Expand Down Expand Up @@ -1054,12 +1057,12 @@ void serveJson(AsyncWebServerRequest* request)
return;
}

GlobalBufferAsyncJsonResponse *response = new GlobalBufferAsyncJsonResponse(subJson==JSON_PATH_FXDATA || subJson==JSON_PATH_EFFECTS); // will clear and convert JsonDocument into JsonArray if necessary
if (!response->owns_lock()) {
JSONBufferGuard guard(17);
if (!guard.owns_lock()) {
request->send(503, "application/json", F("{\"error\":3}"));
delete response;
return;
}
GlobalBufferAsyncJsonResponse *response = new GlobalBufferAsyncJsonResponse(std::move(guard), subJson==JSON_PATH_FXDATA || subJson==JSON_PATH_EFFECTS); // will clear and convert JsonDocument into JsonArray if necessary

JsonVariant lDoc = response->getRoot();

Expand Down