249 lines
9.2 KiB
C
249 lines
9.2 KiB
C
/*
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* This file is part of the Pico FIDO distribution (https://github.com/polhenarejos/pico-fido).
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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 "ctap2_cbor.h"
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#include "fido.h"
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#include "ctap.h"
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#include "hid/ctap_hid.h"
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#include "files.h"
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#include "apdu.h"
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#include "credential.h"
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#include "hsm.h"
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#include "random.h"
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#include "mbedtls/ecdh.h"
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#include "mbedtls/chachapoly.h"
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#include "mbedtls/sha256.h"
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extern uint8_t keydev_dec[32];
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extern bool has_keydev_dec;
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int cbor_config(const uint8_t *data, size_t len) {
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CborParser parser;
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CborValue map;
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CborError error = CborNoError;
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uint64_t subcommand = 0, pinUvAuthProtocol = 0, vendorCommandId = 0, newMinPinLength = 0;
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CborByteString pinUvAuthParam = { 0 }, vendorAutCt = { 0 };
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CborCharString minPinLengthRPIDs[32] = { 0 };
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size_t resp_size = 0, raw_subpara_len = 0, minPinLengthRPIDs_len = 0;
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CborEncoder encoder, mapEncoder;
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uint8_t *raw_subpara = NULL;
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const bool *forceChangePin = NULL;
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CBOR_CHECK(cbor_parser_init(data, len, 0, &parser, &map));
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uint64_t val_c = 1;
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CBOR_PARSE_MAP_START(map, 1)
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{
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uint64_t val_u = 0;
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CBOR_FIELD_GET_UINT(val_u, 1);
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if (val_c <= 1 && val_c != val_u) {
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CBOR_ERROR(CTAP2_ERR_MISSING_PARAMETER);
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}
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if (val_u < val_c) {
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CBOR_ERROR(CTAP2_ERR_INVALID_CBOR);
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}
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val_c = val_u + 1;
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if (val_u == 0x01) {
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CBOR_FIELD_GET_UINT(subcommand, 1);
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}
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else if (val_u == 0x02) {
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uint64_t subpara = 0;
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raw_subpara = (uint8_t *) cbor_value_get_next_byte(&_f1);
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CBOR_PARSE_MAP_START(_f1, 2)
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{
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if (subcommand == 0xff) {
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CBOR_FIELD_GET_UINT(subpara, 2);
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if (subpara == 0x01) {
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CBOR_FIELD_GET_UINT(vendorCommandId, 2);
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}
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else if (subpara == 0x02) {
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CBOR_FIELD_GET_BYTES(vendorAutCt, 2);
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}
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}
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else if (subcommand == 0x03) {
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CBOR_FIELD_GET_UINT(subpara, 2);
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if (subpara == 0x01) {
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CBOR_FIELD_GET_UINT(newMinPinLength, 2);
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}
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else if (subpara == 0x02) {
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CBOR_PARSE_ARRAY_START(_f2, 3)
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{
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CBOR_FIELD_GET_TEXT(minPinLengthRPIDs[minPinLengthRPIDs_len], 3);
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minPinLengthRPIDs_len++;
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if (minPinLengthRPIDs_len >= 32) {
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CBOR_ERROR(CTAP2_ERR_KEY_STORE_FULL);
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}
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}
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CBOR_PARSE_ARRAY_END(_f2, 3);
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}
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else if (subpara == 0x03) {
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CBOR_FIELD_GET_BOOL(forceChangePin, 2);
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}
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}
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}
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CBOR_PARSE_MAP_END(_f1, 2);
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raw_subpara_len = cbor_value_get_next_byte(&_f1) - raw_subpara;
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}
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else if (val_u == 0x03) {
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CBOR_FIELD_GET_UINT(pinUvAuthProtocol, 1);
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}
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else if (val_u == 0x04) {
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CBOR_FIELD_GET_BYTES(pinUvAuthParam, 1);
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}
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}
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CBOR_PARSE_MAP_END(map, 1);
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cbor_encoder_init(&encoder, ctap_resp->init.data + 1, CTAP_MAX_PACKET_SIZE, 0);
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if (pinUvAuthParam.present == false) {
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CBOR_ERROR(CTAP2_ERR_PUAT_REQUIRED);
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}
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if (pinUvAuthProtocol == 0) {
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CBOR_ERROR(CTAP2_ERR_MISSING_PARAMETER);
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}
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uint8_t *verify_payload = (uint8_t *) calloc(1, 32 + 1 + 1 + raw_subpara_len);
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memset(verify_payload, 0xff, 32);
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verify_payload[32] = 0x0d;
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verify_payload[33] = subcommand;
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memcpy(verify_payload + 34, raw_subpara, raw_subpara_len);
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error = verify(pinUvAuthProtocol,
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paut.data,
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verify_payload,
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32 + 1 + 1 + raw_subpara_len,
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pinUvAuthParam.data);
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free(verify_payload);
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if (error != CborNoError) {
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CBOR_ERROR(CTAP2_ERR_PIN_AUTH_INVALID);
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}
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if (!(paut.permissions & CTAP_PERMISSION_ACFG)) {
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CBOR_ERROR(CTAP2_ERR_PIN_AUTH_INVALID);
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}
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if (subcommand == 0xff) {
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if (vendorCommandId == CTAP_CONFIG_AUT_DISABLE) {
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if (!file_has_data(ef_keydev_enc)) {
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CBOR_ERROR(CTAP2_ERR_NOT_ALLOWED);
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}
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if (has_keydev_dec == false) {
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CBOR_ERROR(CTAP2_ERR_PIN_AUTH_INVALID);
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}
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flash_write_data_to_file(ef_keydev, keydev_dec, sizeof(keydev_dec));
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mbedtls_platform_zeroize(keydev_dec, sizeof(keydev_dec));
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flash_write_data_to_file(ef_keydev_enc, NULL, 0); // Set ef to 0 bytes
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low_flash_available();
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}
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else if (vendorCommandId == CTAP_CONFIG_AUT_ENABLE) {
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if (!file_has_data(ef_keydev)) {
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CBOR_ERROR(CTAP2_ERR_NOT_ALLOWED);
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}
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if (mse.init == false) {
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CBOR_ERROR(CTAP2_ERR_NOT_ALLOWED);
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}
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mbedtls_chachapoly_context chatx;
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int ret = mse_decrypt_ct(vendorAutCt.data, vendorAutCt.len);
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if (ret != 0) {
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CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
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}
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uint8_t key_dev_enc[12 + 32 + 16];
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random_gen(NULL, key_dev_enc, 12);
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mbedtls_chachapoly_init(&chatx);
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mbedtls_chachapoly_setkey(&chatx, vendorAutCt.data);
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ret = mbedtls_chachapoly_encrypt_and_tag(&chatx,
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file_get_size(ef_keydev),
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key_dev_enc,
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NULL,
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0,
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file_get_data(ef_keydev),
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key_dev_enc + 12,
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key_dev_enc + 12 + file_get_size(ef_keydev));
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mbedtls_chachapoly_free(&chatx);
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if (ret != 0) {
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CBOR_ERROR(CTAP1_ERR_INVALID_PARAMETER);
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}
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flash_write_data_to_file(ef_keydev_enc, key_dev_enc, sizeof(key_dev_enc));
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mbedtls_platform_zeroize(key_dev_enc, sizeof(key_dev_enc));
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flash_write_data_to_file(ef_keydev, key_dev_enc, file_get_size(ef_keydev)); // Overwrite ef with 0
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flash_write_data_to_file(ef_keydev, NULL, 0); // Set ef to 0 bytes
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low_flash_available();
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}
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else {
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CBOR_ERROR(CTAP2_ERR_INVALID_SUBCOMMAND);
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}
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goto err;
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}
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else if (subcommand == 0x03) {
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uint8_t currentMinPinLen = 4;
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file_t *ef_minpin = search_by_fid(EF_MINPINLEN, NULL, SPECIFY_EF);
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if (file_has_data(ef_minpin)) {
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currentMinPinLen = *file_get_data(ef_minpin);
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}
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if (newMinPinLength == 0) {
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newMinPinLength = currentMinPinLen;
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}
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else if (newMinPinLength > 0 && newMinPinLength < currentMinPinLen) {
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CBOR_ERROR(CTAP2_ERR_PIN_POLICY_VIOLATION);
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}
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if (forceChangePin == ptrue && !file_has_data(ef_pin)) {
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CBOR_ERROR(CTAP2_ERR_PIN_NOT_SET);
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}
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if (file_has_data(ef_pin) && file_get_data(ef_pin)[1] < newMinPinLength) {
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forceChangePin = ptrue;
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}
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uint8_t *data = (uint8_t *) calloc(1, 2 + minPinLengthRPIDs_len * 32);
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data[0] = newMinPinLength;
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data[1] = forceChangePin == ptrue ? 1 : 0;
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for (int m = 0; m < minPinLengthRPIDs_len; m++) {
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mbedtls_sha256((uint8_t *) minPinLengthRPIDs[m].data,
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minPinLengthRPIDs[m].len,
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data + 2 + m * 32,
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0);
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}
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flash_write_data_to_file(ef_minpin, data, 2 + minPinLengthRPIDs_len * 32);
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low_flash_available();
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goto err; //No return
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}
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else if (subcommand == 0x01) {
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set_opts(get_opts() | FIDO2_OPT_EA);
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goto err;
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}
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else {
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CBOR_ERROR(CTAP2_ERR_UNSUPPORTED_OPTION);
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}
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CBOR_CHECK(cbor_encoder_close_container(&encoder, &mapEncoder));
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resp_size = cbor_encoder_get_buffer_size(&encoder, ctap_resp->init.data + 1);
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err:
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CBOR_FREE_BYTE_STRING(pinUvAuthParam);
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CBOR_FREE_BYTE_STRING(vendorAutCt);
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for (int i = 0; i < minPinLengthRPIDs_len; i++) {
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CBOR_FREE_BYTE_STRING(minPinLengthRPIDs[i]);
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}
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if (error != CborNoError) {
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if (error == CborErrorImproperValue) {
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return CTAP2_ERR_CBOR_UNEXPECTED_TYPE;
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}
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return error;
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}
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res_APDU_size = resp_size;
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return 0;
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}
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