40288a85f1
In order to add FIDO2 support, we need to reorganize some USB/CCID calls to specific area (named driver). Thus, pico-hsm-sdk has two drivers: - CCID driver implements APDU over USB/CCID ISO-7816 standard procedures. - HID driver implements APDU over HID. Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/*
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* This file is part of the Pico HSM SDK distribution (https://github.com/polhenarejos/pico-hsm-sdk).
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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 "asn1.h"
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size_t asn1_len_tag(uint16_t tag, size_t len) {
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size_t ret = 1+format_tlv_len(len, NULL)+len;
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if (tag > 0x00ff)
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return ret+1;
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return ret;
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}
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int format_tlv_len(size_t len, uint8_t *out) {
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if (len < 128) {
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if (out)
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*out = len;
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return 1;
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}
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else if (len < 256) {
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if (out) {
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*out++ = 0x81;
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*out++ = len;
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}
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return 2;
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}
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else {
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if (out) {
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*out++ = 0x82;
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*out++ = (len >> 8) & 0xff;
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*out++ = len & 0xff;
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}
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return 3;
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}
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return 0;
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}
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int walk_tlv(const uint8_t *cdata, size_t cdata_len, uint8_t **p, uint16_t *tag, size_t *tag_len, uint8_t **data) {
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if (!p)
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return 0;
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if (!*p)
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*p = (uint8_t *)cdata;
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if (*p-cdata >= cdata_len)
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return 0;
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uint16_t tg = 0x0;
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size_t tgl = 0;
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tg = *(*p)++;
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if ((tg & 0x1f) == 0x1f) {
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tg <<= 8;
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tg |= *(*p)++;
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}
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tgl = *(*p)++;
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if (tgl == 0x82) {
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tgl = *(*p)++ << 8;
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tgl |= *(*p)++;
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}
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else if (tgl == 0x81) {
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tgl = *(*p)++;
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}
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if (tag)
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*tag = tg;
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if (tag_len)
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*tag_len = tgl;
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if (data)
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*data = *p;
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*p = *p+tgl;
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return 1;
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}
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bool asn1_find_tag(const uint8_t *data, size_t data_len, uint16_t itag, size_t *tag_len, uint8_t **tag_data) {
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uint16_t tag = 0x0;
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uint8_t *p = NULL;
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while (walk_tlv(data, data_len, &p, &tag, tag_len, tag_data)) {
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if (itag == tag)
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return true;
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}
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return false;
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}
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