将char数组传递给函数以获取update char数组的值

Question

int get_alpha()
{
    std::string sealed_alpha_file = "/home/roshan/thesis/osn_server/sealed_alpha";

    long fsize;
    ocall_get_textsize(sealed_alpha_file.c_str(), &fsize, 0);
    unsigned char sealed_data[fsize];
    size_t ocall_return;
    ocall_load_file(&ocall_return, sealed_alpha_file.c_str(), fsize, sealed_data, 0);

      char resecret[12];
      uint64_t resecret_size = sizeof(resecret);
      sgx_status_t ret;
      ret = sgx_unseal_data(
              (sgx_sealed_data_t*)sealed_data,
              NULL,
              NULL,
              (uint8_t*)&resecret,
              (uint32_t*)&resecret_size);

      if(ret != SGX_SUCCESS)
      {
          mbedtls_printf("Enclave: Unsealing sealed_alpha failed %#x\n", ret);
          return -1;
      }

    mbedtls_printf("Enclave: Unsealing sealed_alpha success");
    mbedtls_printf("Enclave: After unsealing alpha number: %llu\n", *(char *)resecret);
    return 0;
}

I wanted to call the get_alpha() function from another function and get the value from the resecret char array. I tried to change the get_alpha() to get_alpha(char *resecret) and commented the char resecret[12]; in the get_alpha function and also made uint64_t resecret_size = sizeof(resecret); to uint64_t resecret_size = (12);.

And call it like this from other function

char resecret[12];
get_alpha(resecret);

mbedtls_printf("Enclave: After unsealing alpha number: %llu\n", *(char *)resecret);

But I do not get the correct answer. It seems sgx_unseal_data fails.

The signature of sgx_unseal_data:

sgx_status_t SGXAPI sgx_unseal_data(const sgx_sealed_data_t *p_sealed_data,
    uint8_t *p_additional_MACtext,
    uint32_t *p_additional_MACtext_length,
    uint8_t *p_decrypted_text,
    uint32_t *p_decrypted_text_length);

Answer 1

The marked line seems odd:

ret = sgx_unseal_data(
              (sgx_sealed_data_t*)sealed_data,
              NULL,
              NULL,
              (uint8_t*)&resecret,    // Probably shouldn't use address-of (&) here?
              (uint32_t*)&resecret_size);

I believe the call should be:

ret = sgx_unseal_data(
              (sgx_sealed_data_t*)sealed_data,
              NULL,
              NULL,
              (uint8_t*)resecret,                  
              (uint32_t*)&resecret_size);