c - 将 char 数组传递给函数以获取更新 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;
}

我想从另一个函数调用 get_alpha() 函数并从 resecret char 数组中获取值。我尝试将 get_alpha() 更改为 get_alpha(char *resecret) 并评论 char resecret[12];在 get_alpha 函数中，还制作了 uint64_t resecret_size = sizeof(resecret);到 uint64_t resecret_size = (12);。

并从其他函数中这样调用它

char resecret[12];
get_alpha(resecret);

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

但我没有得到正确的答案。看来 sgx_unseal_data 失败了。

sgx_unseal_data的签名:

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

标记的线看起来很奇怪:

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);

我认为调用应该是:

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