Memory Leak in Status Class and Usage in leveldb

[YancyLii]

Description

There appears to be a potential memory leak issue within the Status class of the leveldb project. This issue was discovered during fuzz testing and further analysis of the source code. The memory leak is primarily associated with the dynamic memory allocation and management within the Status class' constructors and CopyState method.

Reproduce

Memory leaks were detected using a fuzzing tool, which revealed issues during operations involving error status creation and management. extern "C" int LLVMFuzzerTestOneInput(const uint8_t data, size_t size) { leveldb::Slice slice1(reinterpret_cast<const char>(data), size); leveldb::Slice slice2(reinterpret_cast<const char*>(data), size); leveldb::Status status = leveldb::Status::NotFound(slice1, slice2); leveldb::Iterator* iterator = leveldb::NewErrorIterator(status); return 0; }

Analysis

1.Status::CopyState Method: This method allocates memory for a new state string but does not have a corresponding deallocation mechanism. If the returned pointer from CopyState is not properly managed by the calling function, it can lead to memory leaks. 2.Status Constructor: The constructor for creating an error Status object dynamically allocates memory to hold the error message and associated data. However, there is no explicit destructor in the Status class to deallocate this memory once the Status object is no longer in use.

Potential Impact

If these memory allocations are not properly managed, it can lead to memory leaks, which may affect the performance and reliability of applications using the leveldb library, especially in long-running applications where repeated status errors might occur.

Suggested Fix

Implement a destructor in the Status class that properly deallocates the state_ member if it is not nullptr. Ensure that any usage of CopyState handles the allocated memory correctly, preferably by using smart pointers or ensuring that the memory is deleted when no longer needed. Additional Information The memory leak is evident from both fuzz test results and direct code analysis. This issue could potentially be resolved by revising memory management practices within the Status class implementation.