linux-sgx-trts-modified/SampleCode/RemoteAttestation/isv_app/isv_app.cpp

/*
 * Copyright (C) 2011-2016 Intel Corporation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

// This sample is confined to the communication between a SGX client platform
// and an ISV Application Server. 



#include <stdio.h>
#include <limits.h>
#include <unistd.h>
// Needed for definition of remote attestation messages.
#include "remote_attestation_result.h"

#include "isv_enclave_u.h"

// Needed to call untrusted key exchange library APIs, i.e. sgx_ra_proc_msg2.
#include "sgx_ukey_exchange.h"

// Needed to get service provider's information, in your real project, you will
// need to talk to real server.
#include "network_ra.h"

// Needed to create enclave and do ecall.
#include "sgx_urts.h"

// Needed to query extended epid group id.
#include "sgx_uae_service.h"

#include "service_provider.h"

#ifndef SAFE_FREE
#define SAFE_FREE(ptr) {if (NULL != (ptr)) {free(ptr); (ptr) = NULL;}}
#endif

// In addition to generating and sending messages, this application
// can use pre-generated messages to verify the generation of
// messages and the information flow.
#include "sample_messages.h"


#define ENCLAVE_PATH "isv_enclave.signed.so"

uint8_t* msg1_samples[] = { msg1_sample1, msg1_sample2 };
uint8_t* msg2_samples[] = { msg2_sample1, msg2_sample2 };
uint8_t* msg3_samples[MSG3_BODY_SIZE] = { msg3_sample1, msg3_sample2 };
uint8_t* attestation_msg_samples[] =
    { attestation_msg_sample1, attestation_msg_sample2};

// Some utility functions to output some of the data structures passed between
// the ISV app and the remote attestation service provider.
void PRINT_BYTE_ARRAY(
    FILE *file, void *mem, uint32_t len)
{
    if(!mem || !len)
    {
        fprintf(file, "\n( null )\n");
        return;
    }
    uint8_t *array = (uint8_t *)mem;
    fprintf(file, "%u bytes:\n{\n", len);
    uint32_t i = 0;
    for(i = 0; i < len - 1; i++)
    {
        fprintf(file, "0x%x, ", array[i]);
        if(i % 8 == 7) fprintf(file, "\n");
    }
    fprintf(file, "0x%x ", array[i]);
    fprintf(file, "\n}\n");
}


void PRINT_ATTESTATION_SERVICE_RESPONSE(
    FILE *file,
    ra_samp_response_header_t *response)
{
    if(!response)
    {
        fprintf(file, "\t\n( null )\n");
        return;
    }

    fprintf(file, "RESPONSE TYPE:   0x%x\n", response->type);
    fprintf(file, "RESPONSE STATUS: 0x%x 0x%x\n", response->status[0],
            response->status[1]);
    fprintf(file, "RESPONSE BODY SIZE: %u\n", response->size);

    if(response->type == TYPE_RA_MSG2)
    {
        sgx_ra_msg2_t* p_msg2_body = (sgx_ra_msg2_t*)(response->body);

        fprintf(file, "MSG2 gb - ");
        PRINT_BYTE_ARRAY(file, &(p_msg2_body->g_b), sizeof(p_msg2_body->g_b));

        fprintf(file, "MSG2 spid - ");
        PRINT_BYTE_ARRAY(file, &(p_msg2_body->spid), sizeof(p_msg2_body->spid));

        fprintf(file, "MSG2 quote_type : %hx\n", p_msg2_body->quote_type);

        fprintf(file, "MSG2 kdf_id : %hx\n", p_msg2_body->kdf_id);

        fprintf(file, "MSG2 sign_gb_ga - ");
        PRINT_BYTE_ARRAY(file, &(p_msg2_body->sign_gb_ga),
                         sizeof(p_msg2_body->sign_gb_ga));

        fprintf(file, "MSG2 mac - ");
        PRINT_BYTE_ARRAY(file, &(p_msg2_body->mac), sizeof(p_msg2_body->mac));

        fprintf(file, "MSG2 sig_rl - ");
        PRINT_BYTE_ARRAY(file, &(p_msg2_body->sig_rl),
                         p_msg2_body->sig_rl_size);
    }
    else if(response->type == TYPE_RA_ATT_RESULT)
    {
        sample_ra_att_result_msg_t *p_att_result =
            (sample_ra_att_result_msg_t *)(response->body);
        fprintf(file, "ATTESTATION RESULT MSG platform_info_blob - ");
        PRINT_BYTE_ARRAY(file, &(p_att_result->platform_info_blob),
                         sizeof(p_att_result->platform_info_blob));

        fprintf(file, "ATTESTATION RESULT MSG mac - ");
        PRINT_BYTE_ARRAY(file, &(p_att_result->mac), sizeof(p_att_result->mac));

        fprintf(file, "ATTESTATION RESULT MSG secret.payload_tag - %u bytes\n",
                p_att_result->secret.payload_size);

        fprintf(file, "ATTESTATION RESULT MSG secret.payload - ");
        PRINT_BYTE_ARRAY(file, p_att_result->secret.payload,
                p_att_result->secret.payload_size);
    }
    else
    {
        fprintf(file, "\nERROR in printing out the response. "
                       "Response of type not supported %d\n", response->type);
    }
}

// This sample code doesn't have any recovery/retry mechanisms for the remote
// attestation. Since the enclave can be lost due S3 transitions, apps
// susceptible to S3 transitions should have logic to restart attestation in
// these scenarios.
#define _T(x) x
int main(int argc, char* argv[])
{
    int ret = 0;
    ra_samp_request_header_t *p_msg0_full = NULL;
    ra_samp_response_header_t *p_msg0_resp_full = NULL;
    ra_samp_request_header_t *p_msg1_full = NULL;
    ra_samp_response_header_t *p_msg2_full = NULL;
    sgx_ra_msg3_t *p_msg3 = NULL;
    ra_samp_response_header_t* p_att_result_msg_full = NULL;
    sgx_enclave_id_t enclave_id = 0;
    int enclave_lost_retry_time = 1;
    int busy_retry_time = 4;
    sgx_ra_context_t context = INT_MAX;
    sgx_status_t status = SGX_SUCCESS;
    ra_samp_request_header_t* p_msg3_full = NULL;

    int32_t verify_index = -1;
    int32_t verification_samples = sizeof(msg1_samples)/sizeof(msg1_samples[0]);

    FILE* OUTPUT = stdout;

#define VERIFICATION_INDEX_IS_VALID() (verify_index > 0 && \
                                       verify_index <= verification_samples)
#define GET_VERIFICATION_ARRAY_INDEX() (verify_index-1)

    if(argc > 1)
    {

        verify_index = atoi(argv[1]);

        if( VERIFICATION_INDEX_IS_VALID())
        {
            fprintf(OUTPUT, "\nVerifying precomputed attestation messages "
                            "using precomputed values# %d\n", verify_index);
        }
        else
        {
            fprintf(OUTPUT, "\nValid invocations are:\n");
            fprintf(OUTPUT, "\n\tisv_app\n");
            fprintf(OUTPUT, "\n\tisv_app <verification index>\n");
            fprintf(OUTPUT, "\nValid indices are [1 - %d]\n",
                    verification_samples);
            fprintf(OUTPUT, "\nUsing a verification index uses precomputed "
                    "messages to assist debugging the remote attestation "
                    "service provider.\n");
            return -1;
        }
    }

    // Preparation for remote attestation by configuring extended epid group id.
    {
        uint32_t extended_epid_group_id = 0;
        ret = sgx_get_extended_epid_group_id(&extended_epid_group_id);
        if (SGX_SUCCESS != ret)
        {
            ret = -1;
            fprintf(OUTPUT, "\nError, call sgx_get_extended_epid_group_id fail [%s].",
                __FUNCTION__);
            return ret;
        }
        fprintf(OUTPUT, "\nCall sgx_get_extended_epid_group_id success.");

        p_msg0_full = (ra_samp_request_header_t*)
            malloc(sizeof(ra_samp_request_header_t)
            +sizeof(uint32_t));
        if (NULL == p_msg0_full)
        {
            ret = -1;
            goto CLEANUP;
        }
        p_msg0_full->type = TYPE_RA_MSG0;
        p_msg0_full->size = sizeof(uint32_t);

        *(uint32_t*)((uint8_t*)p_msg0_full + sizeof(ra_samp_request_header_t)) = extended_epid_group_id;
        {

            fprintf(OUTPUT, "\nMSG0 body generated -\n");

            PRINT_BYTE_ARRAY(OUTPUT, p_msg0_full->body, p_msg0_full->size);

        }
        // The ISV application sends msg0 to the SP.
        // The ISV decides whether to support this extended epid group id.
        fprintf(OUTPUT, "\nSending msg0 to remote attestation service provider.\n");

        ret = ra_network_send_receive("http://SampleServiceProvider.intel.com/",
            p_msg0_full,
            &p_msg0_resp_full);
        if (ret != 0)
        {
            fprintf(OUTPUT, "\nError, ra_network_send_receive for msg0 failed "
                "[%s].", __FUNCTION__);
            goto CLEANUP;
        }
        fprintf(OUTPUT, "\nSent MSG0 to remote attestation service.\n");
    }
    // Remote attestation will be initiated the ISV server challenges the ISV
    // app or if the ISV app detects it doesn't have the credentials
    // (shared secret) from a previous attestation required for secure
    // communication with the server.
    {
        // ISV application creates the ISV enclave.
        int launch_token_update = 0;
        sgx_launch_token_t launch_token = {0};
        memset(&launch_token, 0, sizeof(sgx_launch_token_t));
        do
        {
            ret = sgx_create_enclave(_T(ENCLAVE_PATH),
                                     SGX_DEBUG_FLAG,
                                     &launch_token,
                                     &launch_token_update,
                                     &enclave_id, NULL);
            if(SGX_SUCCESS != ret)
            {
                ret = -1;
                fprintf(OUTPUT, "\nError, call sgx_create_enclave fail [%s].",
                        __FUNCTION__);
                goto CLEANUP;
            }
            fprintf(OUTPUT, "\nCall sgx_create_enclave success.");

            ret = enclave_init_ra(enclave_id,
                                  &status,
                                  false,
                                  &context);
        //Ideally, this check would be around the full attestation flow.
        } while (SGX_ERROR_ENCLAVE_LOST == ret && enclave_lost_retry_time--);

        if(SGX_SUCCESS != ret || status)
        {
            ret = -1;
            fprintf(OUTPUT, "\nError, call enclave_init_ra fail [%s].",
                    __FUNCTION__);
            goto CLEANUP;
        }
        fprintf(OUTPUT, "\nCall enclave_init_ra success.");

        // isv application call uke sgx_ra_get_msg1
        p_msg1_full = (ra_samp_request_header_t*)
                      malloc(sizeof(ra_samp_request_header_t)
                             + sizeof(sgx_ra_msg1_t));
        if(NULL == p_msg1_full)
        {
            ret = -1;
            goto CLEANUP;
        }
        p_msg1_full->type = TYPE_RA_MSG1;
        p_msg1_full->size = sizeof(sgx_ra_msg1_t);
        do
        {
            ret = sgx_ra_get_msg1(context, enclave_id, sgx_ra_get_ga,
                                  (sgx_ra_msg1_t*)((uint8_t*)p_msg1_full
                                  + sizeof(ra_samp_request_header_t)));
            sleep(3); // Wait 3s between retries
        } while (SGX_ERROR_BUSY == ret && busy_retry_time--);
        if(SGX_SUCCESS != ret)
        {
            ret = -1;
            fprintf(OUTPUT, "\nError, call sgx_ra_get_msg1 fail [%s].",
                    __FUNCTION__);
            goto CLEANUP;
        }
        else
        {
            fprintf(OUTPUT, "\nCall sgx_ra_get_msg1 success.\n");

            fprintf(OUTPUT, "\nMSG1 body generated -\n");

            PRINT_BYTE_ARRAY(OUTPUT, p_msg1_full->body, p_msg1_full->size);

        }

        if(VERIFICATION_INDEX_IS_VALID())
        {

            memcpy_s(p_msg1_full->body, p_msg1_full->size,
                     msg1_samples[GET_VERIFICATION_ARRAY_INDEX()],
                     p_msg1_full->size);

            fprintf(OUTPUT, "\nInstead of using the recently generated MSG1, "
                            "we will use the following precomputed MSG1 -\n");

            PRINT_BYTE_ARRAY(OUTPUT, p_msg1_full->body, p_msg1_full->size);
        }


        // The ISV application sends msg1 to the SP to get msg2,
        // msg2 needs to be freed when no longer needed.
        // The ISV decides whether to use linkable or unlinkable signatures.
        fprintf(OUTPUT, "\nSending msg1 to remote attestation service provider."
                        "Expecting msg2 back.\n");


        ret = ra_network_send_receive("http://SampleServiceProvider.intel.com/",
                                      p_msg1_full,
                                      &p_msg2_full);

        if(ret != 0 || !p_msg2_full)
        {
            fprintf(OUTPUT, "\nError, ra_network_send_receive for msg1 failed "
                            "[%s].", __FUNCTION__);
            if(VERIFICATION_INDEX_IS_VALID())
            {
                fprintf(OUTPUT, "\nBecause we are in verification mode we will "
                                "ignore this error.\n");
                fprintf(OUTPUT, "\nInstead, we will pretend we received the "
                                "following MSG2 - \n");

                SAFE_FREE(p_msg2_full);
                ra_samp_response_header_t* precomputed_msg2 =
                    (ra_samp_response_header_t*)msg2_samples[
                        GET_VERIFICATION_ARRAY_INDEX()];
                const size_t msg2_full_size = sizeof(ra_samp_response_header_t)
                                              +  precomputed_msg2->size;
                p_msg2_full =
                    (ra_samp_response_header_t*)malloc(msg2_full_size);
                if(NULL == p_msg2_full)
                {
                    ret = -1;
                    goto CLEANUP;
                }
                memcpy_s(p_msg2_full, msg2_full_size, precomputed_msg2,
                         msg2_full_size);

                PRINT_BYTE_ARRAY(OUTPUT, p_msg2_full,
                                 sizeof(ra_samp_response_header_t)
                                 + p_msg2_full->size);
            }
            else
            {
                goto CLEANUP;
            }
        }
        else
        {
            // Successfully sent msg1 and received a msg2 back.
            // Time now to check msg2.
            if(TYPE_RA_MSG2 != p_msg2_full->type)
            {

                fprintf(OUTPUT, "\nError, didn't get MSG2 in response to MSG1. "
                                "[%s].", __FUNCTION__);

                if(VERIFICATION_INDEX_IS_VALID())
                {
                    fprintf(OUTPUT, "\nBecause we are in verification mode we "
                                    "will ignore this error.");
                }
                else
                {
                    goto CLEANUP;
                }
            }

            fprintf(OUTPUT, "\nSent MSG1 to remote attestation service "
                            "provider. Received the following MSG2:\n");
            PRINT_BYTE_ARRAY(OUTPUT, p_msg2_full,
                             sizeof(ra_samp_response_header_t)
                             + p_msg2_full->size);

            fprintf(OUTPUT, "\nA more descriptive representation of MSG2:\n");
            PRINT_ATTESTATION_SERVICE_RESPONSE(OUTPUT, p_msg2_full);

            if( VERIFICATION_INDEX_IS_VALID() )
            {
                // The response should match the precomputed MSG2:
                ra_samp_response_header_t* precomputed_msg2 =
                    (ra_samp_response_header_t *)
                    msg2_samples[GET_VERIFICATION_ARRAY_INDEX()];
                if(memcmp( precomputed_msg2, p_msg2_full,
                   sizeof(ra_samp_response_header_t) + p_msg2_full->size))
                {
                    fprintf(OUTPUT, "\nVerification ERROR. Our precomputed "
                                    "value for MSG2 does NOT match.\n");
                    fprintf(OUTPUT, "\nPrecomputed value for MSG2:\n");
                    PRINT_BYTE_ARRAY(OUTPUT, precomputed_msg2,
                                     sizeof(ra_samp_response_header_t)
                                     + precomputed_msg2->size);
                    fprintf(OUTPUT, "\nA more descriptive representation "
                                    "of precomputed value for MSG2:\n");
                    PRINT_ATTESTATION_SERVICE_RESPONSE(OUTPUT,
                                                       precomputed_msg2);
                }
                else
                {
                    fprintf(OUTPUT, "\nVerification COMPLETE. Remote "
                                    "attestation service provider generated a "
                                    "matching MSG2.\n");
                }
            }

        }

        sgx_ra_msg2_t* p_msg2_body = (sgx_ra_msg2_t*)((uint8_t*)p_msg2_full
                                      + sizeof(ra_samp_response_header_t));


        uint32_t msg3_size = 0;
        if( VERIFICATION_INDEX_IS_VALID())
        {
            // We cannot generate a valid MSG3 using the precomputed messages
            // we have been using. We will use the precomputed msg3 instead.
            msg3_size = MSG3_BODY_SIZE;
            p_msg3 = (sgx_ra_msg3_t*)malloc(msg3_size);
            if(NULL == p_msg3)
            {
                ret = -1;
                goto CLEANUP;
            }
            memcpy_s(p_msg3, msg3_size,
                     msg3_samples[GET_VERIFICATION_ARRAY_INDEX()], msg3_size);
            fprintf(OUTPUT, "\nBecause MSG1 was a precomputed value, the MSG3 "
                            "we use will also be. PRECOMPUTED MSG3 - \n");
        }
        else
        {
            busy_retry_time = 2;
            // The ISV app now calls uKE sgx_ra_proc_msg2,
            // The ISV app is responsible for freeing the returned p_msg3!!
            do
            {
                ret = sgx_ra_proc_msg2(context,
                                   enclave_id,
                                   sgx_ra_proc_msg2_trusted,
                                   sgx_ra_get_msg3_trusted,
                                   p_msg2_body,
                                   p_msg2_full->size,
                                   &p_msg3,
                                   &msg3_size);
            } while (SGX_ERROR_BUSY == ret && busy_retry_time--);
            if(!p_msg3)
            {
                fprintf(OUTPUT, "\nError, call sgx_ra_proc_msg2 fail. "
                                "p_msg3 = 0x%p [%s].", p_msg3, __FUNCTION__);
                ret = -1;
                goto CLEANUP;
            }
            if(SGX_SUCCESS != (sgx_status_t)ret)
            {
                fprintf(OUTPUT, "\nError, call sgx_ra_proc_msg2 fail. "
                                "ret = 0x%08x [%s].", ret, __FUNCTION__);
                ret = -1;
                goto CLEANUP;
            }
            else
            {
                fprintf(OUTPUT, "\nCall sgx_ra_proc_msg2 success.\n");
                fprintf(OUTPUT, "\nMSG3 - \n");
            }
        }

        PRINT_BYTE_ARRAY(OUTPUT, p_msg3, msg3_size);

        p_msg3_full = (ra_samp_request_header_t*)malloc(
                       sizeof(ra_samp_request_header_t) + msg3_size);
        if(NULL == p_msg3_full)
        {
            ret = -1;
            goto CLEANUP;
        }
        p_msg3_full->type = TYPE_RA_MSG3;
        p_msg3_full->size = msg3_size;
        if(memcpy_s(p_msg3_full->body, msg3_size, p_msg3, msg3_size))
        {
            fprintf(OUTPUT,"\nError: INTERNAL ERROR - memcpy failed in [%s].",
                    __FUNCTION__);
            ret = -1;
            goto CLEANUP;
        }

        // The ISV application sends msg3 to the SP to get the attestation
        // result message, attestation result message needs to be freed when
        // no longer needed. The ISV service provider decides whether to use
        // linkable or unlinkable signatures. The format of the attestation
        // result is up to the service provider. This format is used for
        // demonstration.  Note that the attestation result message makes use
        // of both the MK for the MAC and the SK for the secret. These keys are
        // established from the SIGMA secure channel binding.
        ret = ra_network_send_receive("http://SampleServiceProvider.intel.com/",
                                      p_msg3_full,
                                      &p_att_result_msg_full);
        if(ret || !p_att_result_msg_full)
        {
            ret = -1;
            fprintf(OUTPUT, "\nError, sending msg3 failed [%s].", __FUNCTION__);
            goto CLEANUP;
        }


        sample_ra_att_result_msg_t * p_att_result_msg_body =
            (sample_ra_att_result_msg_t *)((uint8_t*)p_att_result_msg_full
                                           + sizeof(ra_samp_response_header_t));
        if(TYPE_RA_ATT_RESULT != p_att_result_msg_full->type)
        {
            ret = -1;
            fprintf(OUTPUT, "\nError. Sent MSG3 successfully, but the message "
                            "received was NOT of type att_msg_result. Type = "
                            "%d. [%s].", p_att_result_msg_full->type,
                             __FUNCTION__);
            goto CLEANUP;
        }
        else
        {
            fprintf(OUTPUT, "\nSent MSG3 successfully. Received an attestation "
                            "result message back\n.");
            if( VERIFICATION_INDEX_IS_VALID() )
            {
                if(memcmp(p_att_result_msg_full->body,
                        attestation_msg_samples[GET_VERIFICATION_ARRAY_INDEX()],
                        p_att_result_msg_full->size) )
                {
                    fprintf(OUTPUT, "\nSent MSG3 successfully. Received an "
                                    "attestation result message back that did "
                                    "NOT match the expected value.\n");
                    fprintf(OUTPUT, "\nEXPECTED ATTESTATION RESULT -");
                    PRINT_BYTE_ARRAY(OUTPUT,
                        attestation_msg_samples[GET_VERIFICATION_ARRAY_INDEX()],
                        p_att_result_msg_full->size);
                }
            }
        }

        fprintf(OUTPUT, "\nATTESTATION RESULT RECEIVED - ");
        PRINT_BYTE_ARRAY(OUTPUT, p_att_result_msg_full->body,
                         p_att_result_msg_full->size);


        if( VERIFICATION_INDEX_IS_VALID() )
        {
            fprintf(OUTPUT, "\nBecause we used precomputed values for the "
                            "messages, the attestation result message will "
                            "not pass further verification tests, so we will "
                            "skip them.\n");
            goto CLEANUP;
        }

        // Check the MAC using MK on the attestation result message.
        // The format of the attestation result message is ISV specific.
        // This is a simple form for demonstration. In a real product,
        // the ISV may want to communicate more information.
        ret = verify_att_result_mac(enclave_id,
                &status,
                context,
                (uint8_t*)&p_att_result_msg_body->platform_info_blob,
                sizeof(ias_platform_info_blob_t),
                (uint8_t*)&p_att_result_msg_body->mac,
                sizeof(sgx_mac_t));
        if((SGX_SUCCESS != ret) ||
           (SGX_SUCCESS != status))
        {
            ret = -1;
            fprintf(OUTPUT, "\nError: INTEGRITY FAILED - attestation result "
                            "message MK based cmac failed in [%s].",
                            __FUNCTION__);
            goto CLEANUP;
        }

        bool attestation_passed = true;
        // Check the attestation result for pass or fail.
        // Whether attestation passes or fails is a decision made by the ISV Server.
        // When the ISV server decides to trust the enclave, then it will return success.
        // When the ISV server decided to not trust the enclave, then it will return failure.
        if(0 != p_att_result_msg_full->status[0]
           || 0 != p_att_result_msg_full->status[1])
        {
            fprintf(OUTPUT, "\nError, attestation result message MK based cmac "
                            "failed in [%s].", __FUNCTION__);
            attestation_passed = false;
        }

        // The attestation result message should contain a field for the Platform
        // Info Blob (PIB).  The PIB is returned by attestation server in the attestation report.
        // It is not returned in all cases, but when it is, the ISV app
        // should pass it to the blob analysis API called sgx_report_attestation_status()
        // along with the trust decision from the ISV server.
        // The ISV application will take action based on the update_info.
        // returned in update_info by the API.  
        // This call is stubbed out for the sample.
        // 
        // sgx_update_info_bit_t update_info;
        // ret = sgx_report_attestation_status(
        //     &p_att_result_msg_body->platform_info_blob,
        //     attestation_passed ? 0 : 1, &update_info);

        // Get the shared secret sent by the server using SK (if attestation
        // passed)
        if(attestation_passed)
        {
            ret = put_secret_data(enclave_id,
                                  &status,
                                  context,
                                  p_att_result_msg_body->secret.payload,
                                  p_att_result_msg_body->secret.payload_size,
                                  p_att_result_msg_body->secret.payload_tag);
            if((SGX_SUCCESS != ret)  || (SGX_SUCCESS != status))
            {
                fprintf(OUTPUT, "\nError, attestation result message secret "
                                "using SK based AESGCM failed in [%s]. ret = "
                                "0x%0x. status = 0x%0x", __FUNCTION__, ret,
                                 status);
                goto CLEANUP;
            }
        }
        fprintf(OUTPUT, "\nSecret successfully received from server.");
        fprintf(OUTPUT, "\nRemote attestation success!");
    }

CLEANUP:
    // Clean-up
    // Need to close the RA key state.
    if(INT_MAX != context)
    {
        int ret_save = ret;
        ret = enclave_ra_close(enclave_id, &status, context);
        if(SGX_SUCCESS != ret || status)
        {
            ret = -1;
            fprintf(OUTPUT, "\nError, call enclave_ra_close fail [%s].",
                    __FUNCTION__);
        }
        else
        {
            // enclave_ra_close was successful, let's restore the value that
            // led us to this point in the code.
            ret = ret_save;
        }
        fprintf(OUTPUT, "\nCall enclave_ra_close success.");
    }

    sgx_destroy_enclave(enclave_id);


    ra_free_network_response_buffer(p_msg0_resp_full);
    ra_free_network_response_buffer(p_msg2_full);
    ra_free_network_response_buffer(p_att_result_msg_full);

    // p_msg3 is malloc'd by the untrusted KE library. App needs to free.
    SAFE_FREE(p_msg3);
    SAFE_FREE(p_msg3_full);
    SAFE_FREE(p_msg1_full);
    SAFE_FREE(p_msg0_full);
    printf("\nEnter a character before exit ...\n");
    getchar();
    return ret;
}