sgx_status_t sgx_read_rand(unsigned char *rand, size_t length_in_bytes)
{
// check parameters
//
// rand can be within or outside the enclave
if(!rand || !length_in_bytes)
{
return SGX_ERROR_INVALID_PARAMETER;
}
if(!sgx_is_within_enclave(rand, length_in_bytes) && !sgx_is_outside_enclave(rand, length_in_bytes))
{
return SGX_ERROR_INVALID_PARAMETER;
}
// loop to rdrand
uint32_t rand_num = 0;
while(length_in_bytes > 0)
{
sgx_status_t status = __do_get_rand32(&rand_num);
if(status != SGX_SUCCESS)
{
return status;
}
size_t size = (length_in_bytes < sizeof(rand_num)) ? length_in_bytes : sizeof(rand_num);
memcpy(rand, &rand_num, size);
rand += size;
length_in_bytes -= size;
}
memset_s(&rand_num, sizeof(rand_num), 0, sizeof(rand_num));
return SGX_SUCCESS;
}
/* The function should generate a random number properly, and the pseudo-rand
implementation is only for demo purpose. */
sample_status_t sample_read_rand(unsigned char *rand, size_t length_in_bytes)
{
// check parameters
if(!rand || !length_in_bytes)
{
return SAMPLE_ERROR_INVALID_PARAMETER;
}
// loop to rdrand
while(length_in_bytes > 0)
{
uint32_t rand_num = 0;
sample_status_t status = __do_get_rand32(&rand_num);
if(status != SAMPLE_SUCCESS)
{
return status;
}
size_t size = (length_in_bytes < sizeof(rand_num))
? length_in_bytes : sizeof(rand_num);
if(memcpy_s(rand, size, &rand_num, size))
{
return status;
}
rand += size;
length_in_bytes -= size;
}
return SAMPLE_SUCCESS;
}
