102 lines
3.4 KiB
C
102 lines
3.4 KiB
C
/*
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* This file is part of the Pico HSM distribution (https://github.com/polhenarejos/pico-hsm).
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* Copyright (c) 2022 Pol Henarejos.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 3.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "sc_hsm.h"
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#include "mbedtls/ecdsa.h"
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#include "crypto_utils.h"
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#include "cvc.h"
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#define MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED -0x006E
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#define MOD_ADD(N) \
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while (mbedtls_mpi_cmp_mpi(&(N), &grp->P) >= 0) \
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MBEDTLS_MPI_CHK(mbedtls_mpi_sub_abs(&(N), &(N), &grp->P))
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static inline int mbedtls_mpi_add_mod(const mbedtls_ecp_group *grp,
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mbedtls_mpi *X,
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const mbedtls_mpi *A,
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const mbedtls_mpi *B) {
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(X, A, B));
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MOD_ADD(*X);
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cleanup:
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return ret;
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}
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int cmd_derive_asym() {
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uint8_t key_id = P1(apdu);
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uint8_t dest_id = P2(apdu);
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file_t *fkey;
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if (!isUserAuthenticated) {
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return SW_SECURITY_STATUS_NOT_SATISFIED();
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}
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if (!(fkey = search_file((KEY_PREFIX << 8) | key_id)) || !file_has_data(fkey)) {
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return SW_FILE_NOT_FOUND();
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}
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if (key_has_purpose(fkey, ALGO_EC_DERIVE) == false) {
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return SW_CONDITIONS_NOT_SATISFIED();
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}
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if (apdu.nc == 0) {
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return SW_WRONG_LENGTH();
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}
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if (apdu.data[0] == ALGO_EC_DERIVE) {
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mbedtls_ecp_keypair ctx;
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mbedtls_ecp_keypair_init(&ctx);
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int r;
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r = load_private_key_ec(&ctx, fkey);
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if (r != PICOKEY_OK) {
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mbedtls_ecp_keypair_free(&ctx);
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if (r == PICOKEY_VERIFICATION_FAILED) {
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return SW_SECURE_MESSAGE_EXEC_ERROR();
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}
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return SW_EXEC_ERROR();
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}
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mbedtls_mpi a, nd;
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mbedtls_mpi_init(&a);
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mbedtls_mpi_init(&nd);
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r = mbedtls_mpi_read_binary(&a, apdu.data + 1, apdu.nc - 1);
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if (r != 0) {
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mbedtls_ecp_keypair_free(&ctx);
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mbedtls_mpi_free(&a);
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mbedtls_mpi_free(&nd);
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return SW_DATA_INVALID();
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}
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r = mbedtls_mpi_add_mod(&ctx.grp, &nd, &ctx.d, &a);
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mbedtls_mpi_free(&a);
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if (r != 0) {
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mbedtls_ecp_keypair_free(&ctx);
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mbedtls_mpi_free(&nd);
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return SW_EXEC_ERROR();
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}
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r = mbedtls_mpi_copy(&ctx.d, &nd);
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mbedtls_mpi_free(&nd);
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if (r != 0) {
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mbedtls_ecp_keypair_free(&ctx);
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return SW_EXEC_ERROR();
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}
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r = store_keys(&ctx, PICO_KEYS_KEY_EC, dest_id);
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if (r != PICOKEY_OK) {
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mbedtls_ecp_keypair_free(&ctx);
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return SW_EXEC_ERROR();
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}
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mbedtls_ecp_keypair_free(&ctx);
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}
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else {
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return SW_WRONG_DATA();
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}
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return SW_OK();
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}
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