Allocating a buffer inside an Enclave

Meysam_t_ — Thu, 02 Jan 2020 08:40:24 GMT

Hello,

I am trying to allocate a buffer inside an enclave by using new in an ecall function as follows

This is what I have in Enclave.edl

public int buffer_allocator([out, size=len] char * buffer, size_t len);

And this is what I defined in Enclave.cpp

// to allocate a buffer in EPC

// to allocate a buffer in EPC 
int buffer_allocator(char * buffer, size_t len)
{
    buffer = new char[len];
    if (!buffer)
        return (1);
    else
        return(0);    
    
 }

However, when I am running it, it returns 0 meaning that it fails to allocate memory. The question is how to allocate a buffer inside the enclave?

Hello.

Scott_R_Intel — Fri, 03 Jan 2020 15:59:26 GMT

Hello.

That will allocate the buffer just fine, provided you have set up enough enclave heap size in the Enclave.config.xml for the length of buffer you're trying to allocate.

I think the problem is that you have your null check logic (or return values) backward, which is why you are getting a zero returned... It should be "if (buffer) return 1;" or "if (!buffer) return 0;".

Regards.

Scott

topic Allocating a buffer inside an Enclave in Intel® Software Guard Extensions (Intel® SGX)

Allocating a buffer inside an Enclave

Hello.