Systemsicherheit/7-SGX_Hands-on/src/app/proxysetup.c

445 lines
11 KiB
C

#include <errno.h>
#include <sgx_urts.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/core_names.h>
#include <openssl/sha.h>
#include <openssl/ec.h>
#include <openssl/bn.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <sgx_tcrypto.h>
#include "enclave_u.h"
#include "proxy.h"
#include "util.h"
struct ProxysetupArgs {
char* sealed_key_file_path;
char* sgx_token_path;
};
char* proxysetup_syntax(void) {
return
"proxysetup implementation of the enclave-powered SignatureProxy\n"
" outputs public key on stdout\n"
" -s <path> file path of the sealed proxy key\n"
" -t <path> file path of the sgx token\n";
}
static EVP_PKEY *sgx_public_to_EVP_PKEY(const sgx_ec256_public_t *p_public)
{
EVP_PKEY *evp_key = NULL;
EVP_PKEY_CTX *pkey_ctx = NULL;
BIGNUM *bn_pub_x = NULL;
BIGNUM *bn_pub_y = NULL;
EC_POINT *point = NULL;
EC_GROUP* group = NULL;
OSSL_PARAM_BLD *params_build = NULL;
OSSL_PARAM *params = NULL;
const char *curvename = NULL;
int nid = 0;
size_t key_len;
unsigned char pub_key[SGX_ECP256_KEY_SIZE+4];
group = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
if (group == NULL)
return NULL;
do {
// converts the x value of public key, represented as positive integer in little-endian into a BIGNUM
bn_pub_x = BN_lebin2bn((unsigned char*)p_public->gx, sizeof(p_public->gx), bn_pub_x);
if (NULL == bn_pub_x) {
break;
}
// converts the y value of public key, represented as positive integer in little-endian into a BIGNUM
bn_pub_y = BN_lebin2bn((unsigned char*)p_public->gy, sizeof(p_public->gy), bn_pub_y);
if (NULL == bn_pub_y) {
break;
}
// creates new point and assigned the group object that the point relates to
point = EC_POINT_new(group);
if (NULL == point) {
break;
}
// sets point based on public key's x,y coordinates
if (1 != EC_POINT_set_affine_coordinates(group, point, bn_pub_x, bn_pub_y, NULL)) {
break;
}
// check point if the point is on curve
if (1 != EC_POINT_is_on_curve(group, point, NULL)) {
break;
}
// convert point to octet string
key_len = EC_POINT_point2oct(group, point, POINT_CONVERSION_COMPRESSED, pub_key, sizeof(pub_key), NULL);
if (key_len == 0) {
break;
}
// build OSSL_PARAM
params_build = OSSL_PARAM_BLD_new();
if (NULL == params_build) {
break;
}
nid = EC_GROUP_get_curve_name(group);
if (nid == NID_undef) {
break;
}
curvename = OBJ_nid2sn(nid);
if (curvename == NULL) {
break;
}
if (1 != OSSL_PARAM_BLD_push_utf8_string(params_build, "group", curvename, 0)) {
break;
}
if (1 != OSSL_PARAM_BLD_push_octet_string(params_build, OSSL_PKEY_PARAM_PUB_KEY, pub_key, key_len)) {
break;
}
params = OSSL_PARAM_BLD_to_param(params_build);
if (NULL == params) {
break;
}
// get pkey from params
pkey_ctx = EVP_PKEY_CTX_new_from_name(NULL, "EC", NULL);
if (NULL == pkey_ctx) {
break;
}
if (1 != EVP_PKEY_fromdata_init(pkey_ctx)) {
break;
}
if (1 != EVP_PKEY_fromdata(pkey_ctx, &evp_key, EVP_PKEY_PUBLIC_KEY, params)) {
EVP_PKEY_free(evp_key);
evp_key = NULL;
}
} while(0);
BN_clear_free(bn_pub_x);
BN_clear_free(bn_pub_y);
EC_POINT_clear_free(point);
OSSL_PARAM_free(params);
OSSL_PARAM_BLD_free(params_build);
EVP_PKEY_CTX_free(pkey_ctx);
EC_GROUP_free(group);
return evp_key;
}
static int EVP_PKEY_to_sgx_public(EVP_PKEY* ecdsa_key, sgx_ec256_public_t* sgx_public) {
EC_GROUP* group = NULL;
EC_POINT *point = NULL;
BIGNUM* pub_x = NULL;
BIGNUM* pub_y = NULL;
size_t ec_key_buf_len = 0;
unsigned char ec_key_buf[1024];
int ret;
int retval;
group = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
if (group == NULL)
return 1;
point = EC_POINT_new(group);
if (point == NULL)
return 2;
ret = EVP_PKEY_get_octet_string_param(ecdsa_key, OSSL_PKEY_PARAM_PUB_KEY, ec_key_buf, 1024, &ec_key_buf_len);
if (ret != 1)
return 3;
ret = EC_POINT_oct2point(group, point, ec_key_buf, ec_key_buf_len, NULL);
if (ret != 1){
retval = 4;
goto cleanup;
}
pub_x = BN_new();
pub_y = BN_new();
ret = EC_POINT_get_affine_coordinates(group, point, pub_x, pub_y, NULL);
if (ret != 1){
retval = 5;
goto cleanup;
}
ret = BN_bn2lebinpad(pub_x, sgx_public->gx, SGX_ECP256_KEY_SIZE);
if (ret == -1){
retval = 6;
goto cleanup;
}
ret = BN_bn2lebinpad(pub_y, sgx_public->gy, SGX_ECP256_KEY_SIZE);
if (ret == -1){
retval = 7;
goto cleanup;
}
cleanup:
if (pub_x != NULL)
BN_clear_free(pub_x);
if (pub_y != NULL)
BN_clear_free(pub_y);
if (point != NULL)
EC_POINT_clear_free(point);
if (group != NULL)
EC_GROUP_free(group);
return (retval);
}
/*
sgx_status_t pfz_ecdsa_verify_hash(const uint8_t *p_data,
const sgx_ec256_public_t *p_public,
const sgx_ec256_signature_t *p_signature,
uint8_t *p_result,
sgx_ecc_state_handle_t ecc_handle)
{
if ((ecc_handle == NULL) || (p_public == NULL) || (p_signature == NULL) ||
(p_data == NULL) || (p_result == NULL)) {
return SGX_ERROR_INVALID_PARAMETER;
}
EVP_PKEY_CTX *ctx = NULL;
EVP_PKEY *public_key = NULL;
BIGNUM *bn_r = NULL;
BIGNUM *bn_s = NULL;
ECDSA_SIG *ecdsa_sig = NULL;
unsigned char *sig_data = NULL;
size_t sig_size = 0;
sgx_status_t retval = SGX_ERROR_UNEXPECTED;
int ret = -1;
*p_result = SGX_EC_INVALID_SIGNATURE;
do {
public_key = pfz_get_pub_key_from_coords(p_public, ecc_handle);
if(NULL == public_key) {
break;
}
// converts the x value of the signature, represented as positive integer in little-endian into a BIGNUM
//
bn_r = BN_lebin2bn((unsigned char*)p_signature->x, sizeof(p_signature->x), 0);
if (NULL == bn_r) {
break;
}
// converts the y value of the signature, represented as positive integer in little-endian into a BIGNUM
//
bn_s = BN_lebin2bn((unsigned char*)p_signature->y, sizeof(p_signature->y), 0);
if (NULL == bn_s) {
break;
}
// allocates a new ECDSA_SIG structure (note: this function also allocates the BIGNUMs) and initialize it
//
ecdsa_sig = ECDSA_SIG_new();
if (NULL == ecdsa_sig) {
retval = SGX_ERROR_OUT_OF_MEMORY;
break;
}
// setes the r and s values of ecdsa_sig
// calling this function transfers the memory management of the values to the ECDSA_SIG object,
// and therefore the values that have been passed in should not be freed directly after this function has been called
//
if (1 != ECDSA_SIG_set0(ecdsa_sig, bn_r, bn_s)) {
ECDSA_SIG_free(ecdsa_sig);
ecdsa_sig = NULL;
break;
}
sig_size = i2d_ECDSA_SIG(ecdsa_sig, &sig_data);
if (sig_size <= 0) {
break;
}
ctx = EVP_PKEY_CTX_new(public_key, NULL);
if (!ctx) {
break;
}
if (1 != EVP_PKEY_verify_init(ctx)) {
break;
}
if (1 != EVP_PKEY_CTX_set_signature_md(ctx, EVP_sha256())) {
break;
}
ret = EVP_PKEY_verify(ctx, sig_data, sig_size, p_data, SGX_SHA256_HASH_SIZE);
if (ret < 0) {
break;
}
// sets the p_result based on verification result
//
if (ret == 1)
*p_result = SGX_EC_VALID;
retval = SGX_SUCCESS;
} while(0);
if (ecdsa_sig) {
ECDSA_SIG_free(ecdsa_sig);
bn_r = NULL;
bn_s = NULL;
}
if (ctx)
EVP_PKEY_CTX_free(ctx);
if (public_key)
EVP_PKEY_free(public_key);
if (bn_r)
BN_clear_free(bn_r);
if (bn_s)
BN_clear_free(bn_s);
return retval;
}
sgx_status_t pfz_ecc256_open_context(sgx_ecc_state_handle_t* p_ecc_handle)
{
if (p_ecc_handle == NULL) {
return SGX_ERROR_INVALID_PARAMETER;
}
sgx_status_t retval = SGX_SUCCESS;
EC_GROUP* ec_group = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
if (NULL == ec_group) {
retval = SGX_ERROR_UNEXPECTED;
} else {
*p_ecc_handle = (void*)ec_group;
}
return retval;
}
sgx_status_t pfz_ecdsa_verify(const uint8_t *p_data,
uint32_t data_size,
const sgx_ec256_public_t *p_public,
const sgx_ec256_signature_t *p_signature,
uint8_t *p_result,
sgx_ecc_state_handle_t ecc_handle)
{
if ((ecc_handle == NULL) || (p_public == NULL) || (p_signature == NULL) ||
(p_data == NULL) || (data_size < 1) || (p_result == NULL)) {
return SGX_ERROR_INVALID_PARAMETER;
}
unsigned char digest[SGX_SHA256_HASH_SIZE] = { 0 };
SHA256((const unsigned char *)p_data, data_size, (unsigned char *)digest);
return (pfz_ecdsa_verify_hash(digest, p_public, p_signature, p_result, ecc_handle));
}
*/
int handle_proxysetup(int argc, char** argv) {
struct ProxysetupArgs args = {
NULL,
NULL
};
FILE* sealed_file;
sgx_status_t sgx_ret;
/*
* Parse Input
*/
int i = 0;
while(i < argc) {
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.sealed_key_file_path == NULL)
syntax_exit();
/*
* Initialize SGX Enclave
*/
if (initialize_enclave(args.sgx_token_path) != 0)
exit(1);
/*
* Setup Sealed Keypair
*/
sealed_file = fopen(args.sealed_key_file_path, "wb");
if(sealed_file == NULL){
perror("Error opening sealed_key_file file");
exit(1);
}
int sealed_size;
sgx_ret = get_sealed_size(get_global_eid(), &sealed_size);
if (sgx_ret != SGX_SUCCESS) {
print_error_message(sgx_ret);
exit (1);
}
uint8_t* sealed = malloc(sizeof(uint8_t)*sealed_size);
if (sealed == NULL) {
fprintf(stderr, "failed to allocate for sealed key");
exit(1);
}
/*
* Use Enclave To Generate Keypair
*/
generate_key_pair(get_global_eid(), &sgx_ret, sealed, sealed_size);
if (sgx_ret != SGX_SUCCESS) {
print_error_message(sgx_ret);
exit (1);
}
/*
* Store Sealed Keypair
*/
if (fwrite(sealed, sealed_size, 1, sealed_file) != 1 || ferror(sealed_file) != 0) {
fprintf(stderr, "failed to write sealed key");
exit(1);
}
fflush(sealed_file);
fclose(sealed_file);
/*
* Fetch Public Key From Enclave And Print
*/
sgx_ec256_public_t sgx_public_key;
get_public_key(get_global_eid(), &sgx_ret, sealed, sealed_size, (uint8_t*)&sgx_public_key);
if (sgx_ret != SGX_SUCCESS) {
print_error_message(sgx_ret);
exit (1);
}
EVP_PKEY* public_key = sgx_public_to_EVP_PKEY(&sgx_public_key);
if (PEM_write_PUBKEY(stdout, public_key, NULL, NULL) != 1) {
fprintf(stderr, "could not write publickey\n");
exit (EXIT_FAILURE);
}
fflush(stdout);
EVP_PKEY_free(public_key);
free(sealed);
exit(0);
}