/*
 * 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
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 */


#include "type_length_value.h"
#include "sgx_tcrypto_internal.h"
#include <sgx_trts.h>
#include "epid_utility.h"
#include "aeerror.h"
#include "PVEClass.h"
#include "se_wrapper.h"
#include "oal/internal_log.h"
/**
* File: epid_provision_msg4.cpp 
* Description: Provide the untrusted implementation of code to process ProvMsg4
*
* Untrusted Code for EPID Provision
*/
#define MSG4_TOP_FIELDS_COUNT    3
#define MSG4_TOP_FIELD_NONCE tlvs_msg4[0]
#define MSG4_TOP_FIELD_DATA  tlvs_msg4[1]
#define MSG4_TOP_FIELD_MAC   tlvs_msg4[2]

#define MSG4_FIELD1_COUNT  6
#define MSG4_FIELD1_DEVICE_ID   tlvs_field1[5]
#define MSG4_FIELD1_ENC_TCB     tlvs_field1[0]
#define MSG4_FIELD1_MAC_TCB     tlvs_field1[1]
#define MSG4_FIELD1_ENC_Axf     tlvs_field1[2]
#define MSG4_FIELD1_MAC_Axf     tlvs_field1[3]
#define MSG4_FIELD1_GROUP_CERT  tlvs_field1[4]


static ae_error_t msg4_integrity_checking(const TLVsMsg& tlvs_msg4)
{
    uint32_t tlv_count = tlvs_msg4.get_tlv_count();
    if(tlv_count != MSG4_TOP_FIELDS_COUNT)
        return PVE_INTEGRITY_CHECK_ERROR;
    if(MSG4_TOP_FIELD_NONCE.type != TLV_NONCE || MSG4_TOP_FIELD_NONCE.size != NONCE_SIZE || 
        MSG4_TOP_FIELD_NONCE.version != TLV_VERSION_1 || MSG4_TOP_FIELD_NONCE.header_size != SMALL_TLV_HEADER_SIZE)
        return PVE_INTEGRITY_CHECK_ERROR;
    if(MSG4_TOP_FIELD_DATA.type != TLV_BLOCK_CIPHER_TEXT || MSG4_TOP_FIELD_DATA.version != TLV_VERSION_1)
        return PVE_INTEGRITY_CHECK_ERROR;
    if(MSG4_TOP_FIELD_MAC.type != TLV_MESSAGE_AUTHENTICATION_CODE || MSG4_TOP_FIELD_MAC.version != TLV_VERSION_1 ||
        MSG4_TOP_FIELD_MAC.size != MAC_SIZE || MSG4_TOP_FIELD_MAC.header_size != SMALL_TLV_HEADER_SIZE)
        return PVE_INTEGRITY_CHECK_ERROR;
    return AE_SUCCESS;
}

static ae_error_t msg4_field1_msg_checking(const TLVsMsg& tlvs_field1)
{
    uint32_t tlv_count = tlvs_field1.get_tlv_count();
    if(tlv_count!=MSG4_FIELD1_COUNT){
        return PVE_MSG_ERROR;
    }
    uint32_t i;
    for(i=0;i<tlv_count;++i)
        if(tlvs_field1[i].version != TLV_VERSION_1)
            return PVE_MSG_ERROR;


    if(MSG4_FIELD1_GROUP_CERT.type != TLV_EPID_GROUP_CERT||
        MSG4_FIELD1_GROUP_CERT.size != sizeof(signed_epid_group_cert_t)||
        MSG4_FIELD1_GROUP_CERT.header_size != SMALL_TLV_HEADER_SIZE)
        return PVE_MSG_ERROR;

    if(MSG4_FIELD1_DEVICE_ID.type != TLV_DEVICE_ID ||
        MSG4_FIELD1_DEVICE_ID.size != sizeof(device_id_t)||
        MSG4_FIELD1_DEVICE_ID.header_size != SMALL_TLV_HEADER_SIZE)
        return PVE_MSG_ERROR;
    if(MSG4_FIELD1_ENC_TCB.type != TLV_BLOCK_CIPHER_TEXT||
        MSG4_FIELD1_ENC_TCB.size != BLOCK_CIPHER_TEXT_TLV_PAYLOAD_SIZE(SK_SIZE))
        return PVE_MSG_ERROR;
    if(MSG4_FIELD1_MAC_TCB.type != TLV_MESSAGE_AUTHENTICATION_CODE||
        MSG4_FIELD1_MAC_TCB.size != MAC_SIZE ||
        MSG4_FIELD1_MAC_TCB.header_size != SMALL_TLV_HEADER_SIZE)
        return PVE_MSG_ERROR;
    if(MSG4_FIELD1_ENC_Axf.type != TLV_BLOCK_CIPHER_TEXT||
        MSG4_FIELD1_ENC_Axf.size != BLOCK_CIPHER_TEXT_TLV_PAYLOAD_SIZE(HARD_CODED_EPID_MEMBER_WITH_ESCROW_TLV_SIZE))
        return PVE_MSG_ERROR;
    if(MSG4_FIELD1_MAC_Axf.type != TLV_MESSAGE_AUTHENTICATION_CODE||
        MSG4_FIELD1_MAC_Axf.size != MAC_SIZE||
        MSG4_FIELD1_MAC_Axf.header_size != SMALL_TLV_HEADER_SIZE)
        return PVE_MSG_ERROR;
    return AE_SUCCESS;
}

//Function to check message header of ProvMsg4 to determine whether it is valid
//@msg4_header, input the message header of ProvMsg4
//@return AE_SUCCESS if the message header is valid ProvMsg4 or error code if there're any problems
static ae_error_t check_prov_msg4_header(const provision_response_header_t *msg4_header, uint32_t msg4_size)
{
    if(msg4_header->protocol != SE_EPID_PROVISIONING || msg4_header->type != TYPE_PROV_MSG4 ||
        msg4_header->version != TLV_VERSION_1){
            return PVE_INTEGRITY_CHECK_ERROR;
    }
    uint32_t size_in_header = lv_ntohl(msg4_header->size);
    if(size_in_header + PROVISION_RESPONSE_HEADER_SIZE != msg4_size)
        return PVE_INTEGRITY_CHECK_ERROR;
    return AE_SUCCESS;
}


//Function to decode ProvMsg4 and generate epid data blob
uint32_t CPVEClass::proc_prov_msg4(
        bool  use_ek2_in_input,
        const uint8_t ek2[SK_SIZE],
        const uint8_t* msg4,
        uint32_t msg4_size,
        uint8_t* data_blob,
        uint32_t blob_size)
{
    ae_error_t ret = AE_SUCCESS;
    uint8_t local_ek2[SK_SIZE];
    uint8_t *decoded_msg4 = NULL;
    const provision_response_header_t *msg4_header = reinterpret_cast<const provision_response_header_t *>(msg4);
    if(msg4_size < PROVISION_RESPONSE_HEADER_SIZE){
        AESM_DBG_ERROR("invalid msg4 size");
        return PVE_MSG_ERROR;
    }
    if(blob_size != HARD_CODED_EPID_BLOB_SIZE){
        AESM_DBG_FATAL("invalid input epid blob size");
        return PVE_PARAMETER_ERROR;
    }

    ret = check_prov_msg4_header(msg4_header, msg4_size);
    if( AE_SUCCESS != ret){
        AESM_DBG_ERROR("Invalid ProvMsg4 Header:%d",ret);
        return ret;
    }
    ret = check_epid_pve_pg_status_before_mac_verification(msg4_header);
    if( AE_SUCCESS != ret){
        AESM_DBG_ERROR("Backend return failure in ProvMsg4 Header:%d",ret);
        return ret;
    }

    do{
        TLVsMsg tlvs_msg4;
        tlv_status_t tlv_status;
        tlv_status = tlvs_msg4.init_from_buffer(msg4+static_cast<uint32_t>(PROVISION_RESPONSE_HEADER_SIZE), msg4_size - static_cast<uint32_t>(PROVISION_RESPONSE_HEADER_SIZE));
        ret = tlv_error_2_pve_error(tlv_status);
        if(AE_SUCCESS!=ret){
            AESM_DBG_ERROR("fail to decode ProvMsg4:%d",tlv_status);
            break;
        }
        ret = msg4_integrity_checking(tlvs_msg4);
        if(AE_SUCCESS != ret){
            AESM_DBG_ERROR("ProvMsg4 integrity checking error:%d",ret);
            break;
        }
        AESM_DBG_TRACE("ProvMsg4 decoded");
        if(!use_ek2_in_input){ //we need generate ek2
            prov_get_ek2_input_t ek2_input;
            if(memcpy_s(ek2_input.nonce, NONCE_SIZE, MSG4_TOP_FIELD_NONCE.payload, NONCE_SIZE)!=0){
                AESM_DBG_ERROR("fail in memcpy");
                ret = PVE_UNEXPECTED_ERROR;
                break;
            }
            if(memcpy_s(ek2_input.xid, XID_SIZE, msg4_header->xid, XID_SIZE)!=0){
                AESM_DBG_ERROR("fail in memcpy");
                ret = PVE_UNEXPECTED_ERROR;
                break;
            }
            //call PvE to get EK2
            se_static_assert(SK_SIZE == sizeof(prov_get_ek2_output_t));

            ret = (ae_error_t)get_ek2(&ek2_input, reinterpret_cast<prov_get_ek2_output_t *>(local_ek2));
            if(AE_SUCCESS != ret){
                AESM_DBG_ERROR("fail to get EK2:%d",ret);
                break;
            }
        }else{//reuse ek2 generated in processing ProvMsg2
            if(0!=memcpy_s(local_ek2, sizeof(local_ek2), ek2, SK_SIZE)){
                AESM_DBG_ERROR("fail in memcpy");
                ret = PVE_UNEXPECTED_ERROR;
                break;
            }
        }
        se_static_assert(SK_SIZE==sizeof(sgx_aes_gcm_128bit_key_t));
        tlv_msg_t field1 = block_cipher_tlv_get_encrypted_text(MSG4_TOP_FIELD_DATA);
        decoded_msg4 = reinterpret_cast<uint8_t *>(malloc(field1.msg_size));
        if(NULL == decoded_msg4){
            AESM_DBG_ERROR("malloc error");
            ret = AE_OUT_OF_MEMORY_ERROR;
            break;
        }
        sgx_status_t sgx_status = sgx_rijndael128GCM_decrypt(reinterpret_cast<const sgx_aes_gcm_128bit_key_t *>(local_ek2),
            field1.msg_buf, field1.msg_size, decoded_msg4, 
            reinterpret_cast<uint8_t *>(block_cipher_tlv_get_iv(MSG4_TOP_FIELD_DATA)), IV_SIZE, 
            reinterpret_cast<const uint8_t *>(msg4_header), PROVISION_RESPONSE_HEADER_SIZE,
            reinterpret_cast<const sgx_aes_gcm_128bit_tag_t *>(MSG4_TOP_FIELD_MAC.payload));
        if(SGX_ERROR_MAC_MISMATCH == sgx_status){
            AESM_DBG_ERROR("fail to decrypt ProvMsg4 by EK2");
            ret = PVE_INTEGRITY_CHECK_ERROR;
            break;
        }
        if( AE_SUCCESS != (ret = sgx_error_to_ae_error(sgx_status))){
            AESM_DBG_ERROR("error in decrypting ProvMsg4:%d",sgx_status);
            break;
        }
        AESM_DBG_TRACE("ProvMsg4 decrypted by EK2 successfully");
        ret = check_epid_pve_pg_status_after_mac_verification(msg4_header);
        if(AE_SUCCESS != ret){
            AESM_DBG_ERROR("Backend reported error passed MAC verification:%d",ret);
            break;
        }
        TLVsMsg tlvs_field1;
        tlv_status = tlvs_field1.init_from_buffer(decoded_msg4, field1.msg_size);
        ret = tlv_error_2_pve_error(tlv_status);
        if(AE_SUCCESS != ret){
            AESM_DBG_ERROR("ProvMsg4 Field2.1 decoding failed:%d",tlv_status);
            break;
        }
        ret = msg4_field1_msg_checking(tlvs_field1);
        if( AE_SUCCESS != ret){
            AESM_DBG_ERROR("ProvMsg4 Field2.1 invalid:%d",ret);
            break;
        }
        proc_prov_msg4_input_t msg4_input;
        if(sizeof(proc_prov_msg4_output_t)!=SGX_TRUSTED_EPID_BLOB_SIZE){
            AESM_DBG_FATAL("Trusted ProvMsg4 output buffer size error");
            ret = PVE_UNEXPECTED_ERROR;
            break;
        }
        tlv_msg_t tcb_data = block_cipher_tlv_get_encrypted_text(MSG4_FIELD1_ENC_TCB);
        tlv_msg_t Axf_data = block_cipher_tlv_get_encrypted_text(MSG4_FIELD1_ENC_Axf);
        if(0!=memcpy_s(&msg4_input.group_cert, sizeof(msg4_input.group_cert), MSG4_FIELD1_GROUP_CERT.payload, MSG4_FIELD1_GROUP_CERT.size)||
            0!=memcpy_s(&msg4_input.equivalent_psvn, sizeof(psvn_t), device_id_tlv_get_psvn(MSG4_FIELD1_DEVICE_ID), sizeof(psvn_t))||
            0!=memcpy_s(&msg4_input.fmsp, sizeof(fmsp_t), device_id_tlv_get_fmsp(MSG4_FIELD1_DEVICE_ID), sizeof(fmsp_t))||
            0!=memcpy_s(&msg4_input.tcb_iv, IV_SIZE, block_cipher_tlv_get_iv(MSG4_FIELD1_ENC_TCB), IV_SIZE)||
            0!=memcpy_s(&msg4_input.encrypted_tcb, SK_SIZE, tcb_data.msg_buf, tcb_data.msg_size)||
            0!=memcpy_s(&msg4_input.tcb_mac, MAC_SIZE, MSG4_FIELD1_MAC_TCB.payload, MSG4_FIELD1_MAC_TCB.size)||
            0!=memcpy_s(&msg4_input.member_credential_iv, IV_SIZE, block_cipher_tlv_get_iv(MSG4_FIELD1_ENC_Axf), IV_SIZE)||
            0!=memcpy_s(&msg4_input.encrypted_member_credential, HARD_CODED_EPID_MEMBER_WITH_ESCROW_TLV_SIZE, Axf_data.msg_buf, Axf_data.msg_size)||
            0!=memcpy_s(&msg4_input.member_credential_mac, MAC_SIZE, MSG4_FIELD1_MAC_Axf.payload, MSG4_FIELD1_MAC_Axf.size)){
                AESM_DBG_ERROR("memcpy error");
                ret = PVE_UNEXPECTED_ERROR;
                break;
        }
        ret = (ae_error_t)proc_prov_msg4_data(&msg4_input, reinterpret_cast<proc_prov_msg4_output_t *>(data_blob));
        AESM_DBG_TRACE("PvE return %d in Process ProvMsg4",ret);
    }while(0);
    if(decoded_msg4)free(decoded_msg4);
    return ret;
}