[security] Without verifying whether malloc is successful, write the user_key outside directly

[jmp0x7c00]

sgx_status_t enclave_get_user_key(unsigned char *enc_user_key, size_t enc_user_key_len,
				  unsigned char *iv, size_t iv_len, sgx_aes_gcm_128bit_tag_t *tag)
{
  sgx_status_t ctx;
  sgx_ra_key_128_t k;
  
  sgx_status_t get_keys_ret = sgx_ra_get_keys(ctx, SGX_RA_KEY_SK, &k);
  if ( get_keys_ret != SGX_SUCCESS ) return get_keys_ret;
  

  // doesn't check user_key  is not NULL
  unsigned char *user_key = (unsigned char*)malloc(16); 
  sgx_status_t ret;
  
  //decrypt user's key that was used for encrypting source & data.
  ret = sgx_rijndael128GCM_decrypt(&k, enc_user_key, enc_user_key_len, user_key, iv, 12, NULL, 0, tag);
  
  print_hexstring(enc_user_key,16);
  print_hexstring(iv,12);
  print_hexstring((unsigned char*)tag,16);
  print_hexstring(user_key,16);
  
  //for security reason
  memset(user_key, 0x00, 16);
  free(user_key);
  
  return ret;
}

[LeoneChen]

Besides, sgx_ra_get_keys expects ctx is "Context returned by sgx_ra_init."

But it gives uninitialized sgx_status_t