How Should Object Memory be Freed Inside an Intel® Software Guard Extensions (Intel® SGX) Enclave?

• Enclave includes C++ objects like classes and unique_ptrs.
• Unable to determine how to free the memory for C++ objects in the enclave.

Within enclaves, use the C++ delete operator to free memory that was previously allocated to classes, unique_ptrs, and other objects using the new operator. The operators new and delete behave the same within enclaves as they do in regular C++ applications.

Sample Code:

test.h:

class{

private:

  ClassA* ca;

  unique_ptr<ClassB> cb;

}

test.cpp:

//Use new to instantiate the class and unique_ptr objects

ca = new ClassA*(...); 

cb = make_unique<ClassB>(function(...));

//Use delete to free the memory previously allocated with new

delete ClassA;

delete cb;

Refer to the C++ Language Support section in the Intel® Software Guard Extensions (Intel® SGX) SDK Developer Reference Guide for your operating system for more information.

• Intel SGX SDK Developer Reference Guide for Windows*
• The Intel SGX Developer Reference for Linux is in the Documentation folder of the latest release of the Intel® Software Guard Extensions SDK for Linux*.