[Assignment-7] Flake + App base

- Add Assignment-7 to flake.nix
- Implement basic framework of app
- Implement proxy subcommand (mostly)
- Implement basics of intermediary subcommand

7-SGX_Hands-on/src/app/intermediary.c

@@ -0,0 +1,153 @@
+#include <errno.h>
+#include <sgx_urts.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "enclave.h"
+#include "intermediary.h"
+#include "util.h"
+
+#define HASH_BYTES 32
+#define HASH_CHUNK_BYTES 32
+#define KEY_BYTES 32
+
+struct IntermediaryArgs {
+    char* firmware_path;
+    char* key_path;
+    char* output_path;
+};
+
+char* intermediary_syntax(void) {
+    return 
+        "intermediary    mock up implementation of the employee binary\n"
+        "    -f <path>   file path to Firmware file\n"
+        "    -k <path>   key file path\n"
+        "    -o <path>   output file path\n";
+}
+
+int handle_intermediary(int argc, char** argv) {
+    struct IntermediaryArgs args = {
+        NULL,
+        NULL,
+        NULL
+    };
+    FILE* firmware_file;
+    FILE* key_file;
+    FILE* output_file;
+    //uint8_t firmware_hash[HASH_BYTES];
+    uint8_t firmware_chunk[HASH_CHUNK_BYTES];
+    uint8_t key[KEY_BYTES];
+    //EVP_MD_CTX *mdctx;
+    //const EVP_MD *md;
+    //unsigned char md_value[EVP_MAX_MD_SIZE];
+    //unsigned int md_len;
+
+    int i = 0;
+    while(i < argc) {
+        if(strcmp(argv[i], "-f")==0 && argc-i >=2){
+            args.firmware_path = argv[i+1];
+            i += 2;
+        }else if(strcmp(argv[i], "-k")==0 && argc-i >=2){
+            args.key_path = argv[i+1];
+            i += 2;
+        }else if(strcmp(argv[i], "-o")==0 && argc-i >=2){
+            args.output_path = argv[i+1];
+            i += 2;
+        }else
+            syntax_exit();
+    }
+
+    if(args.firmware_path == NULL || args.key_path == NULL || args.output_path == NULL)
+        syntax_exit();
+
+    firmware_file = fopen(args.firmware_path, "r");
+    if(firmware_file == NULL){
+        perror("Error opening firmware file");
+        exit(1);
+    }
+
+    /*
+    md = EVP_sha3_256();
+    mdctx = EVP_MD_CTX_new();
+    if (!EVP_DigestSignInit(mdctx, NULL, md, NULL, key)) {
+        fprintf(stderr, "Message digest initialization failed.\n");
+        EVP_MD_CTX_free(mdctx);
+        exit(1);
+    }
+    */
+
+    size_t chunk_len = HASH_CHUNK_BYTES;
+    while(chunk_len==HASH_CHUNK_BYTES) {
+        chunk_len = fread(&firmware_chunk, HASH_CHUNK_BYTES, 1, firmware_file);
+        if(chunk_len!=HASH_CHUNK_BYTES&&ferror(firmware_file)!=0){
+            perror("Failed to read firmware file");
+            exit(1);
+        }
+
+        /*
+        if (!EVP_DigestSignUpdate(mdctx, firmware_chunk, chunk_len)) {
+            printf("Message digest update failed.\n");
+            EVP_MD_CTX_free(mdctx);
+            exit(1);
+        }
+        */
+    }
+
+    /*
+    if (!EVP_DigestSignFinal_ex(mdctx, md_value, &md_len)) {
+        printf("Message digest finalization failed.\n");
+        EVP_MD_CTX_free(mdctx);
+        exit(1);
+    }
+    EVP_MD_CTX_free(mdctx);
+
+    printf("Digest is: ");
+    for (i = 0; i < md_len; i++)
+        printf("%02x", md_value[i]);
+    printf("\n");
+    */
+
+    key_file = fopen(args.key_path, "r");
+    if(key_file == NULL){
+        perror("Error opening key file");
+        exit(1);
+    }
+
+    size_t key_len = fread(&key, 1, KEY_BYTES, key_file);
+    if(ferror(key_file)!=0){
+        perror("Failed to read key");
+        exit(1);
+    }
+    if(key_len != KEY_BYTES){
+        fprintf(stderr, "invalid key length\n");
+        exit(1);
+    }
+
+    //eckey = EC_KEY_new_by_curve_name(NID_secp256r1);
+    //if(eckey == NULL) {
+    //    fprintf(stderr, "failed to initialize SECP256R1 key\n");
+    //    exit(1);
+    //}
+
+    //if (!EC_KEY_generate_key(eckey)) {
+    //    fprintf(stderr, "failed to generate key\n");
+    //    exit(1);
+    //}
+
+    //sig = ECDSA_do_sign(md_value, md_len, eckey);
+    //if (sig == NULL){
+    //    fprintf(stderr, "failed to sign firmware hash\n");
+    //    exit(1);
+    //}
+
+    output_file = fopen(args.output_path, "w");
+    if(output_file == NULL){
+        perror("Error opening output file");
+        exit(1);
+    }
+
+    printf("intermediary %s %s %s", args.firmware_path, args.key_path, args.output_path);
+    exit(0);
+}

7-SGX_Hands-on/src/app/intermediary.h

@@ -0,0 +1,23 @@
+#ifndef _APP_INTERMEDIARY_H_
+#define _APP_INTERMEDIARY_H_
+
+
+/*
+ * @brief getter for intermediary subcommand syntax string
+ *
+ * @returns null-terminated syntax string
+ */
+char* intermediary_syntax(void);
+
+/*
+ * @brief CLI implementation for the "intermediary" subcommand
+ *
+ * @param argc number of arguments with command and subcommand stripped
+ * @param argv arguments with command and subcommand stripped
+ *
+ * @returns 0 on success, else error with output on stderr
+ */
+int handle_intermediary(int argc, char** argv);
+
+
+#endif

7-SGX_Hands-on/src/app/main.c

@@ -0,0 +1,24 @@
+#include <errno.h>
+#include <string.h>
+
+#include "intermediary.h"
+#include "proxy.h"
+#include "util.h"
+
+
+int main(int argc, char** argv) {
+    if(argc < 1)
+        syntax_exit();
+    BIN_NAME = argv[0];
+    if(argc < 2)
+        syntax_exit();
+
+    char* command = argv[1];
+
+    if(strcmp(command, "intermediary")==0)
+        handle_intermediary(argc-2, argv+2);
+    else if (strcmp(command, "proxy")==0)
+        handle_proxy(argc-2, argv+2);
+    else
+        syntax_exit();
+}

7-SGX_Hands-on/src/app/proxy.c

@@ -0,0 +1,235 @@
+#include <errno.h>
+#include <sgx_urts.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "enclave.h"
+#include "proxy.h"
+#include "util.h"
+
+sgx_enclave_id_t global_eid = 0;
+
+struct ProxyArgs {
+    char* input_path;
+    char* output_path;
+    char* sealed_key_file_path;
+    char* sgx_token_path;
+};
+
+typedef struct _sgx_errlist_t {
+    sgx_status_t err;
+    const char *msg;
+    const char *sug; /* Suggestion */
+} sgx_errlist_t;
+
+/* Error code returned by sgx_create_enclave */
+static sgx_errlist_t sgx_errlist[] = {
+    {
+        SGX_ERROR_UNEXPECTED,
+        "Unexpected error occurred.",
+        NULL
+    },
+    {
+        SGX_ERROR_INVALID_PARAMETER,
+        "Invalid parameter.",
+        NULL
+    },
+    {
+        SGX_ERROR_OUT_OF_MEMORY,
+        "Out of memory.",
+        NULL
+    },
+    {
+        SGX_ERROR_ENCLAVE_LOST,
+        "Power transition occurred.",
+        "Please refer to the sample \"PowerTransition\" for details."
+    },
+    {
+        SGX_ERROR_INVALID_ENCLAVE,
+        "Invalid enclave image.",
+        NULL
+    },
+    {
+        SGX_ERROR_INVALID_ENCLAVE_ID,
+        "Invalid enclave identification.",
+        NULL
+    },
+    {
+        SGX_ERROR_INVALID_SIGNATURE,
+        "Invalid enclave signature.",
+        NULL
+    },
+    {
+        SGX_ERROR_OUT_OF_EPC,
+        "Out of EPC memory.",
+        NULL
+    },
+    {
+        SGX_ERROR_NO_DEVICE,
+        "Invalid SGX device.",
+        "Please make sure SGX module is enabled in the BIOS, and install SGX driver afterwards."
+    },
+    {
+        SGX_ERROR_MEMORY_MAP_CONFLICT,
+        "Memory map conflicted.",
+        NULL
+    },
+    {
+        SGX_ERROR_INVALID_METADATA,
+        "Invalid enclave metadata.",
+        NULL
+    },
+    {
+        SGX_ERROR_DEVICE_BUSY,
+        "SGX device was busy.",
+        NULL
+    },
+    {
+        SGX_ERROR_INVALID_VERSION,
+        "Enclave version was invalid.",
+        NULL
+    },
+    {
+        SGX_ERROR_INVALID_ATTRIBUTE,
+        "Enclave was not authorized.",
+        NULL
+    },
+    {
+        SGX_ERROR_ENCLAVE_FILE_ACCESS,
+        "Can't open enclave file.",
+        NULL
+    },
+};
+
+/* Check error conditions for loading enclave */
+static void print_error_message(sgx_status_t ret)
+{
+    size_t idx = 0;
+    size_t ttl = sizeof sgx_errlist/sizeof sgx_errlist[0];
+
+    for (idx = 0; idx < ttl; idx++) {
+        if(ret == sgx_errlist[idx].err) {
+            if(NULL != sgx_errlist[idx].sug)
+                printf("Info: %s\n", sgx_errlist[idx].sug);
+            printf("Error: %s\n", sgx_errlist[idx].msg);
+            break;
+        }
+    }
+    
+    if (idx == ttl)
+    	printf("Error code is 0x%X. Please refer to the \"Intel SGX SDK Developer Reference\" for more details.\n", ret);
+}
+
+static int initialize_enclave(char* token_path) {
+    FILE* sgx_token_file;
+    sgx_launch_token_t token = {0};
+    sgx_status_t ret;
+    int updated = 0;
+
+    sgx_token_file = fopen(token_path, "r");
+    if(sgx_token_file == NULL){
+        perror("Error opening sgx token file");
+        exit(1);
+    }
+
+    size_t read_num = fread(token, 1, sizeof(sgx_launch_token_t), sgx_token_file);
+    if (read_num != 0 && read_num != sizeof(sgx_launch_token_t)) {
+        fprintf(stderr, "sgx token file is corrupted");
+        return (1);
+    }
+
+   ret = sgx_create_enclave("enclave.so", SGX_DEBUG_FLAG, &token, &updated, &global_eid, NULL);
+    if (ret != SGX_SUCCESS) {
+        print_error_message(ret);
+        return (1);
+    }
+
+    if (updated) {
+        sgx_token_file = freopen(token_path, "w", sgx_token_file);
+        if(sgx_token_file == NULL){
+            perror("Error opening sgx token file");
+            return (1);
+        }
+        size_t write_num = fwrite(token, 1, sizeof(sgx_launch_token_t), sgx_token_file);
+        if (write_num != sizeof(sgx_launch_token_t)){
+            fprintf(stderr,"Warning: Failed to save launch token to \"%s\".\n", token_path);
+            return (1);
+        }
+    }
+    return (0);
+}
+
+char* proxy_syntax(void) {
+    return
+        "proxy           implementation of the enclave-powered SignatureProxy\n"
+        "    -i <path>   file path to the intermediary output(signature of firmware)\n"
+        "    -o <path>   output path of the signature\n"
+        "    -s <path>   file path of the sealed proxy key\n"
+        "    -t <path>   file path of the sgx token\n";
+}
+
+int handle_proxy(int argc, char** argv) {
+    struct ProxyArgs args = {
+        NULL,
+        NULL,
+        NULL,
+        NULL
+    };
+    FILE* input_file;
+    FILE* output_file;
+    FILE* sealed_key_file;
+
+    int i = 0;
+    while(i < argc) {
+        if(strcmp(argv[i], "-i")==0 && argc-i >=2){
+            args.input_path = argv[i+1];
+            i += 2;
+        }else if(strcmp(argv[i], "-o")==0 && argc-i >=2){
+            args.output_path = argv[i+1];
+            i += 2;
+        }else if(strcmp(argv[i], "-s")==0 && argc-i >=2){
+            args.sealed_key_file_path = argv[i+1];
+            i += 2;
+        }else if(strcmp(argv[i], "-t")==0 && argc-i >=2){
+            args.sgx_token_path = argv[i+1];
+            i += 2;
+        }else
+            syntax_exit();
+    }
+
+    if(args.input_path == NULL || args.output_path == NULL || args.sealed_key_file_path == NULL || args.sgx_token_path == NULL)
+        syntax_exit();
+
+    input_file = fopen(args.input_path, "r");
+    if(input_file == NULL){
+        perror("Error opening input file");
+        exit(1);
+    }
+
+    output_file = fopen(args.output_path, "w");
+    if(output_file == NULL){
+        perror("Error opening output file");
+        exit(1);
+    }
+
+    //TODO read input -> calculate size of input (ECDSA of SHA3-256 of Firmware File, generated by intermediary)
+    //TODO read sealed key -> calculate size or dynamic alloc
+
+    sealed_key_file = fopen(args.sealed_key_file_path, "w");
+    if(sealed_key_file == NULL){
+        perror("Error opening sealed_key_file file");
+        exit(1);
+    }
+
+    if (initialize_enclave(args.sgx_token_path) != 0)
+        exit(1);
+
+    //TODO call enclave -> refactor interface to do verify and sign in one call to avoid trip through "untrusted" land.
+
+    //TODO store sealed key if changed
+    //TODO write output
+
+    printf("proxy %s %s", args.input_path, args.output_path);
+    exit(0);
+}

7-SGX_Hands-on/src/app/proxy.h

@@ -0,0 +1,23 @@
+#ifndef _APP_PROXY_H_
+#define _APP_PROXY_H_
+
+
+/*
+ * @brief getter for proxy subcommand syntax string
+ *
+ * @returns null-terminated syntax string
+ */
+char* proxy_syntax(void);
+
+/*
+ * @brief CLI implementation for the "proxy" subcommand
+ *
+ * @param argc number of arguments with command and subcommand stripped
+ * @param argv arguments with command and subcommand stripped
+ *
+ * @returns 0 on success, else error with output on stderr
+ */
+int handle_proxy(int argc, char** argv);
+
+
+#endif

7-SGX_Hands-on/src/app/test.c

@@ -0,0 +1,3 @@
+int main() {
+    return (0);
+}

7-SGX_Hands-on/src/app/util.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "util.h"
+#include "proxy.h"
+#include "intermediary.h"
+
+
+char* BIN_NAME = "SignatureProxy";
+
+void syntax_exit(void) {
+    char* syntax =
+        "SignatureProxy Version 0.0.0\n"
+        "Syntax: %s <command> <arguments>\n"
+        "\n"
+        "Commands:\n"
+        "%s"
+        "\n"
+        "%s";
+
+    printf(syntax, BIN_NAME, intermediary_syntax(), proxy_syntax());
+    exit(1);
+}

7-SGX_Hands-on/src/app/util.h

@@ -0,0 +1,13 @@
+#ifndef _APP_UTIL_H_
+#define _APP_UTIL_H_
+
+
+char* BIN_NAME;
+
+/*
+ * @brief prints the command syntax and exits with EXIT_FAILURE
+ */
+void syntax_exit(void);
+
+
+#endif

7-SGX_Hands-on/src/enclave/enclave.c

@@ -0,0 +1,266 @@
+/*
+ * Copyright (C) 2011-2018 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.
+ *
+ */
+
+
+#include <stdarg.h>
+#include <stdio.h>      /* vsnprintf */
+#include <string.h>
+#include <stdlib.h>
+
+#include "Enclave.h"
+#include "Enclave_t.h"
+#include <sgx_tseal.h>
+#include <sgx_error.h>
+#include <sgx_tcrypto.h>
+
+#ifndef SK_SIZE
+#define SK_SIZE SGX_ECP256_KEY_SIZE
+#endif
+
+#ifndef PK_SIZE
+#define PK_SIZE 2*SK_SIZE
+#endif
+
+#ifndef SI_SIZE
+#define SI_SIZE 2*SK_SIZE
+#endif
+
+int get_sealed_size() {
+    return sgx_calc_sealed_data_size(PK_SIZE, SK_SIZE);
+}
+
+int get_signature_size() {
+    return SI_SIZE;
+}
+
+int get_public_key_size() {
+    return PK_SIZE;
+}
+
+int get_private_key_size() {
+    return SK_SIZE;
+}
+
+sgx_status_t seal_key_pair(sgx_ec256_private_t *private, sgx_ec256_public_t *public, uint8_t **sealed, uint32_t sealed_size) {
+    // invalid parameter handling
+    if((private == NULL) || (public == NULL))
+        return SGX_ERROR_INVALID_PARAMETER;
+
+    // allocate temporary buffers on stack
+    uint8_t pk[PK_SIZE] = {0};
+    uint8_t sk[SK_SIZE] = {0};
+
+    // copy key pair into buffers
+    memcpy(pk, public->gx, PK_SIZE);
+    memcpy(sk, private->r, SK_SIZE);
+
+    // calculate needed size
+    uint32_t size = get_sealed_size();
+    if(size > sealed_size) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // seal keypair
+    return sgx_seal_data(PK_SIZE, (const uint8_t *)pk, SK_SIZE, (const uint8_t *)sk, size, (sgx_sealed_data_t *) *sealed);
+}
+
+sgx_status_t unseal_key_pair(const uint8_t *sealed, sgx_ec256_private_t *private, sgx_ec256_public_t *public) {
+    // invalid parameter handling
+    if(sealed == NULL) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // allocate temporary buffers on stack
+    uint8_t pk[PK_SIZE] = {0};
+    uint8_t sk[SK_SIZE] = {0};
+    
+    // calculate public_key size and return error for unexpected results
+    uint32_t pk_size = sgx_get_add_mac_txt_len((const sgx_sealed_data_t *)sealed);
+    uint32_t sk_size = sgx_get_encrypt_txt_len((const sgx_sealed_data_t *)sealed);
+    if ((pk_size != PK_SIZE) || (sk_size != SK_SIZE)) {
+        return SGX_ERROR_UNEXPECTED;
+    }
+
+    // unseal ecc key pair
+    sgx_status_t status = sgx_unseal_data((const sgx_sealed_data_t *)sealed, pk, &pk_size, sk, &sk_size);
+    if (status != SGX_SUCCESS) {
+        return status;
+    }
+
+    // copy buffers into key structs
+    if(public != NULL) {
+        memcpy(public->gx, pk, PK_SIZE);
+    }
+    if (private != NULL) {
+        memcpy(private->r, sk, SK_SIZE);
+    }
+
+    // return success
+    return status;
+}
+
+sgx_status_t get_public_key(const uint8_t *sealed, uint32_t sealed_size, uint8_t *gx, uint32_t gx_size, uint8_t *gy, uint32_t gy_size) {
+    // invalid parameter handling
+    if((sealed == NULL) || (sealed_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // unseal public key
+    sgx_status_t status;
+    sgx_ec256_public_t public;
+    if((status = unseal_key_pair(sealed, NULL, &public)) != SGX_SUCCESS) {
+        return status;
+    }
+
+    // copy public key into return buffers
+    if((gx != NULL) && (gy != NULL)) {
+        memcpy(gx, public.gx, SK_SIZE);
+        memcpy(gy, public.gy, SK_SIZE);
+    }
+
+    // return success
+    return status;
+}
+
+sgx_status_t sign_firmware(const uint8_t *data, uint32_t data_size, uint8_t *sealed, uint32_t sealed_size, uint8_t *signature, uint32_t signature_size) {
+    // invalid parameter handling
+    if((data == NULL) || (data_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if((sealed == NULL) || (sealed_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+    
+    // declare need structures
+    sgx_ecc_state_handle_t ecc_handle;
+    sgx_ec256_private_t private;
+    sgx_ec256_public_t public;
+
+    // open ecc handle
+    sgx_status_t status;
+    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
+        return status;
+    }
+
+    // try unseal keypair
+    sgx_status_t seal_status;
+    if(seal_status = unseal_key_pair(sealed, &private, NULL) != SGX_SUCCESS) {
+        if((status = sgx_ecc256_create_key_pair(&private, &public, ecc_handle)) != SGX_SUCCESS) {
+            sgx_ecc256_close_context(ecc_handle);
+            return status;
+        }
+    }
+
+    // create signature
+    sgx_ec256_signature_t ecc_signature;
+    if((status = sgx_ecdsa_sign(data, data_size, &private, &ecc_signature, ecc_handle)) != SGX_SUCCESS) {
+        sgx_ecc256_close_context(ecc_handle);
+        return status;
+    }
+
+    // TODO: possible wrong endianess for other programms
+    // copy signature to return buffer
+    if((signature == NULL) || (signature_size == 0)) {
+        sgx_ecc256_close_context(ecc_handle);
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+    memcpy(signature, ecc_signature.x, SI_SIZE);
+
+    // seal the key
+    if((seal_status != SGX_SUCCESS) && (sealed != NULL)) {
+        seal_status = seal_key_pair(&private, &public, &sealed, sealed_size);
+    }
+
+    // close ecc handle and return success
+    sgx_ecc256_close_context(ecc_handle);
+    return seal_status;
+}
+
+sgx_status_t verify_firmware(const uint8_t *data, uint32_t data_size, const uint8_t *sealed, uint32_t sealed_size, const uint8_t *public_key, uint32_t public_key_size, const uint8_t *signature, uint32_t signature_size) {
+    // invalid parameter handling
+    if((data == NULL) || (data_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if(((sealed == NULL) || (sealed_size == 0)) && ((public_key == NULL) || (public_key_size == 0))) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if((sealed != NULL) && (public_key != NULL)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    } else if((signature == NULL) || (signature_size == 0)) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // declare need structures
+    sgx_ec256_signature_t ecc_signature;
+    sgx_ecc_state_handle_t ecc_handle;
+    sgx_ec256_public_t public;
+
+    // invalid signature
+    if(signature_size > SI_SIZE) {
+        return SGX_ERROR_INVALID_PARAMETER;
+    }
+
+    // open ecc handle
+    sgx_status_t status;
+    if((status = sgx_ecc256_open_context(&ecc_handle)) != SGX_SUCCESS) {
+        return status;
+    }
+
+    // copy signature into struct
+    memcpy(ecc_signature.x, signature, SI_SIZE);
+
+    // verify signature from staff or enclave
+    if(public_key != NULL) {
+        // invalid public key
+        if(public_key_size != PK_SIZE) {
+            return SGX_ERROR_INVALID_PARAMETER;
+        }
+
+        // copy public key into struct
+        memcpy(public.gx, public_key, PK_SIZE);
+    } else {
+        // unseal public key
+        if(unseal_key_pair(sealed, NULL, &public) != SGX_SUCCESS) {
+            sgx_ecc256_close_context(ecc_handle);
+            return SGX_ERROR_UNEXPECTED;
+        }
+    }
+
+    // verify signature
+    uint8_t result;
+    sgx_status_t verification_status = sgx_ecdsa_verify((const uint8_t *)data, data_size, (const sgx_ec256_public_t *)&public, (const sgx_ec256_signature_t *)&ecc_signature, &result, ecc_handle);
+
+    // handle failed verification process
+    if(verification_status != SGX_SUCCESS) {
+        result = verification_status;
+    }
+
+    // close handle and return result
+    sgx_ecc256_close_context(ecc_handle);
+    return result;
+}

7-SGX_Hands-on/src/enclave/enclave.config.xml

@@ -0,0 +1,12 @@
+<EnclaveConfiguration>
+  <ProdID>0</ProdID>
+  <ISVSVN>0</ISVSVN>
+  <StackMaxSize>0x400000</StackMaxSize>
+  <HeapMaxSize>0x1000000</HeapMaxSize>
+  <TCSNum>10</TCSNum>
+  <TCSPolicy>1</TCSPolicy>
+  <!-- Recommend changing 'DisableDebug' to 1 to make the enclave undebuggable for enclave release -->
+  <DisableDebug>0</DisableDebug>
+  <MiscSelect>0</MiscSelect>
+  <MiscMask>0xFFFFFFFF</MiscMask>
+</EnclaveConfiguration>

7-SGX_Hands-on/src/enclave/enclave.edl

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2011-2018 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.
+ *
+ */
+
+/* Enclave.edl - Top EDL file. */
+
+enclave {
+    
+    /* Import ECALL/OCALL from sub-directory EDLs.
+     *  [from]: specifies the location of EDL file. 
+     *  [import]: specifies the functions to import, 
+     *  [*]: implies to import all functions.
+     */
+    
+    trusted {
+        public int get_sealed_size();
+        public int get_signature_size();
+        public int get_public_key_size();
+        public int get_private_key_size();
+        public sgx_status_t get_public_key([in, size=sealed_size]const uint8_t *sealed, uint32_t sealed_size, [out, size=gx_size]uint8_t *gx, uint32_t gx_size, [out, size=gx_size]uint8_t *gy, uint32_t gy_size);
+        public sgx_status_t sign_firmware([in, size=data_size]const uint8_t *data, uint32_t data_size, [in, out, size=sealed_size]uint8_t *sealed, uint32_t sealed_size, [out, size=signature_size]uint8_t *signature, uint32_t signature_size);
+        public sgx_status_t verify_firmware([in, size=data_size]const uint8_t *data, uint32_t data_size, [in, size=sealed_size]const uint8_t *sealed, uint32_t sealed_size, [in, size=public_key_size]const uint8_t *public_key, uint32_t public_key_size, [in, size=signature_size]const uint8_t *signature, uint32_t signature_size);
+    };
+
+    /* 
+     * ocall_print_string - invokes OCALL to display string buffer inside the enclave.
+     *  [in]: copy the string buffer to App outside.
+     *  [string]: specifies 'str' is a NULL terminated buffer.
+     */
+    untrusted {
+        
+    };
+};

7-SGX_Hands-on/src/enclave/enclave.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2011-2018 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.
+ *
+ */
+
+
+#ifndef _ENCLAVE_H_
+#define _ENCLAVE_H_
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+#include <sgx_error.h>
+
+int get_sealed_size();
+int get_signature_size();
+int get_public_key_size();
+int get_private_key_size();
+
+sgx_status_t get_public_key(const uint8_t *sealed, const uint32_t sealed_size, uint8_t *gx, uint32_t gx_size, uint8_t *gy, uint32_t gy_size);
+sgx_status_t sign_firmware(const uint8_t *data, uint32_t data_size, uint8_t *sealed, uint32_t sealed_size, uint8_t *signature, uint32_t signature_size);
+sgx_status_t verify_firmware(const uint8_t *data, uint32_t data_size, const uint8_t *sealed, uint32_t sealed_size, const uint8_t *public_key, uint32_t public_key_size, const uint8_t *signature, uint32_t signature_size);
+
+#endif /* !_ENCLAVE_H_ */