Files
pico-fido/src/fido/fido.c
2022-09-07 20:03:34 +02:00

244 lines
8.0 KiB
C

/*
* This file is part of the Pico FIDO distribution (https://github.com/polhenarejos/pico-fido).
* Copyright (c) 2022 Pol Henarejos.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "common.h"
#include "fido.h"
#include "hsm.h"
#include "apdu.h"
#include "u2f.h"
#include "files.h"
#include "file.h"
#include "usb.h"
#include "random.h"
#include "mbedtls/ecdsa.h"
#include "mbedtls/x509_crt.h"
#include "mbedtls/hkdf.h"
#include "pk_wrap.h"
#include "crypto_utils.h"
#include <stdio.h>
void init_fido();
int fido_process_apdu();
int fido_unload();
const uint8_t fido_aid[] = {
8,
0xA0, 0x00, 0x00, 0x06, 0x47, 0x2F, 0x00, 0x01
};
app_t *fido_select(app_t *a) {
a->aid = fido_aid;
a->process_apdu = fido_process_apdu;
a->unload = fido_unload;
current_app = a;
init_fido();
return a;
}
void __attribute__ ((constructor)) fido_ctor() {
register_app(fido_select);
//fido_select(&apps[0]);
}
int fido_unload() {
return CCID_OK;
}
int x509_create_cert(mbedtls_ecdsa_context *ecdsa, uint8_t *buffer, size_t buffer_size) {
mbedtls_x509write_cert ctx;
mbedtls_x509write_crt_init(&ctx);
mbedtls_x509write_crt_set_version(&ctx, MBEDTLS_X509_CRT_VERSION_3);
mbedtls_x509write_crt_set_validity(&ctx, "20220901000000", "20320831235959" );
mbedtls_x509write_crt_set_issuer_name(&ctx, "C=ES,O=Pico HSM,CN=Pico FIDO");
mbedtls_x509write_crt_set_subject_name(&ctx, "C=ES,O=Pico HSM,CN=Pico FIDO");
mbedtls_mpi serial;
mbedtls_mpi_init(&serial);
mbedtls_mpi_fill_random(&serial, 32, random_gen, NULL);
mbedtls_x509write_crt_set_serial(&ctx, &serial);
mbedtls_pk_context key;
mbedtls_pk_init(&key);
mbedtls_pk_setup(&key, mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY));
key.pk_ctx = ecdsa;
mbedtls_x509write_crt_set_subject_key(&ctx, &key);
mbedtls_x509write_crt_set_issuer_key(&ctx, &key);
mbedtls_x509write_crt_set_md_alg(&ctx, MBEDTLS_MD_SHA256);
mbedtls_x509write_crt_set_basic_constraints(&ctx, 0, 0);
mbedtls_x509write_crt_set_subject_key_identifier(&ctx);
mbedtls_x509write_crt_set_authority_key_identifier(&ctx);
mbedtls_x509write_crt_set_key_usage(&ctx, MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_KEY_CERT_SIGN);
int ret = mbedtls_x509write_crt_der(&ctx, buffer, buffer_size, random_gen, NULL);
return ret;
}
int load_keydev(uint8_t *key) {
if (!ef_keydev || file_get_size(ef_keydev) == 0)
return CCID_ERR_MEMORY_FATAL;
memcpy(key, file_get_data(ef_keydev), file_get_size(ef_keydev));
//return mkek_decrypt(key, file_get_size(ef_keydev));
return CCID_OK;
}
int derive_key(const uint8_t *app_id, bool new_key, uint8_t *key_handle, mbedtls_ecdsa_context *key) {
uint8_t outk[64] = {0};
int r = 0;
memset(outk, 0, sizeof(outk));
if ((r = load_keydev(outk)) != CCID_OK)
return r;
const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA512);
for (int i = 0; i < KEY_PATH_ENTRIES; i++)
{
if (new_key == true) {
uint32_t val = 0x80000000 | *((uint32_t *)random_bytes_get(sizeof(uint32_t)));
memcpy(&key_handle[i*sizeof(uint32_t)], &val, sizeof(uint32_t));
}
if ((r = mbedtls_hkdf(md_info, &key_handle[i], sizeof(uint32_t), outk, 32, outk + 32, 32, outk, sizeof(outk))) != 0)
{
mbedtls_platform_zeroize(outk, sizeof(outk));
return r;
}
}
if (new_key == true) {
uint8_t key_base[U2F_APPID_SIZE + KEY_PATH_LEN];
memcpy(key_base, app_id, U2F_APPID_SIZE);
memcpy(key_base + U2F_APPID_SIZE, key_handle, KEY_PATH_LEN);
if ((r = mbedtls_md_hmac(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), outk, 32, key_base, sizeof(key_base), key_handle + 32)) != 0)
{
mbedtls_platform_zeroize(outk, sizeof(outk));
return r;
}
}
if (key != NULL) {
mbedtls_ecp_group_load(&key->grp, MBEDTLS_ECP_DP_SECP256R1);
r = mbedtls_ecp_read_key(MBEDTLS_ECP_DP_SECP256R1, key, outk, 32);
mbedtls_platform_zeroize(outk, sizeof(outk));
if (r != 0)
return r;
return mbedtls_ecp_mul(&key->grp, &key->Q, &key->d, &key->grp.G, random_gen, NULL );
}
mbedtls_platform_zeroize(outk, sizeof(outk));
return r;
}
int scan_files() {
ef_keydev = search_by_fid(EF_KEY_DEV, NULL, SPECIFY_EF);
if (ef_keydev) {
if (!ef_keydev->data) {
printf("KEY DEVICE is empty. Generating SECP256R1 curve...");
mbedtls_ecdsa_context ecdsa;
mbedtls_ecdsa_init(&ecdsa);
uint8_t index = 0;
int ret = mbedtls_ecdsa_genkey(&ecdsa, MBEDTLS_ECP_DP_SECP256R1, random_gen, &index);
if (ret != 0) {
mbedtls_ecdsa_free(&ecdsa);
return ret;
}
uint8_t kdata[32];
int key_size = mbedtls_mpi_size(&ecdsa.d);
mbedtls_mpi_write_binary(&ecdsa.d, kdata, key_size);
ret = flash_write_data_to_file(ef_keydev, kdata, key_size);
mbedtls_platform_zeroize(kdata, sizeof(kdata));
if (ret != CCID_OK) {
mbedtls_ecdsa_free(&ecdsa);
return ret;
}
printf(" done!\n");
}
}
else {
printf("FATAL ERROR: KEY DEV not found in memory!\r\n");
}
ef_certdev = search_by_fid(EF_EE_DEV, NULL, SPECIFY_EF);
if (ef_certdev) {
if (file_get_size(ef_certdev) == 0 || !ef_certdev->data) {
uint8_t cert[4096];
mbedtls_ecdsa_context key;
mbedtls_ecdsa_init(&key);
int ret = mbedtls_ecp_read_key(MBEDTLS_ECP_DP_SECP256R1, &key, file_get_data(ef_keydev), 32);
printf("ret %d\n", ret);
if (ret != 0)
return ret;
ret = x509_create_cert(&key, cert, sizeof(cert));
mbedtls_ecdsa_free(&key);
printf("ret %d\n", ret);
if (ret <= 0)
return ret;
flash_write_data_to_file(ef_certdev, cert + sizeof(cert) - ret, ret);
DEBUG_PAYLOAD(cert + sizeof(cert) - ret, ret);
}
}
else {
printf("FATAL ERROR: CERT DEV not found in memory!\r\n");
}
ef_counter = search_by_fid(EF_COUNTER, NULL, SPECIFY_EF);
if (ef_counter) {
if (file_get_size(ef_counter) == 0 || !ef_counter->data) {
uint32_t v = 0;
flash_write_data_to_file(ef_counter, (uint8_t *)&v, sizeof(v));
}
}
else {
printf("FATAL ERROR: Global counter not found in memory!\r\n");
}
low_flash_available();
return CCID_OK;
}
void scan_all() {
scan_flash();
}
void init_fido() {
scan_all();
}
bool wait_button_pressed() {
uint32_t val = EV_PRESS_BUTTON;
queue_try_add(&card_to_usb_q, &val);
do {
queue_remove_blocking(&usb_to_card_q, &val);
} while (val != EV_BUTTON_PRESSED && val != EV_BUTTON_TIMEOUT);
return val == EV_BUTTON_TIMEOUT;
}
typedef struct cmd
{
uint8_t ins;
int (*cmd_handler)();
} cmd_t;
extern int cmd_register();
extern int cmd_authenticate();
extern int cmd_version();
static const cmd_t cmds[] = {
{ U2F_REGISTER, cmd_register },
{ U2F_AUTHENTICATE, cmd_authenticate },
{ U2F_VERSION, cmd_version },
{ 0x00, 0x0}
};
int fido_process_apdu() {
for (const cmd_t *cmd = cmds; cmd->ins != 0x00; cmd++)
{
if (cmd->ins == INS(apdu)) {
int r = cmd->cmd_handler();
return r;
}
}
return SW_INS_NOT_SUPPORTED();
}