It's a major reorganization.

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>

src/asn1.c

@@ -0,0 +1,91 @@
+/*
+ * This file is part of the Pico HSM SDK distribution (https://github.com/polhenarejos/pico-hsm-sdk).
+ * 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 "asn1.h"
+
+size_t asn1_len_tag(uint16_t tag, size_t len) {
+    size_t ret = 1+format_tlv_len(len, NULL)+len;
+    if (tag > 0x00ff)
+        return ret+1;
+    return ret;
+}
+
+int format_tlv_len(size_t len, uint8_t *out) {
+    if (len < 128) {
+        if (out)
+            *out = len;
+        return 1;
+    }
+    else if (len < 256) {
+        if (out) {
+            *out++ = 0x81;
+            *out++ = len;
+        }
+        return 2;
+    }
+    else {
+        if (out) {
+            *out++ = 0x82;
+            *out++ = (len >> 8) & 0xff;
+            *out++ = len & 0xff;
+        }
+        return 3;
+    }
+    return 0;
+}
+
+int walk_tlv(const uint8_t *cdata, size_t cdata_len, uint8_t **p, uint16_t *tag, size_t *tag_len, uint8_t **data) {
+    if (!p)
+        return 0;
+    if (!*p)
+        *p = (uint8_t *)cdata;
+    if (*p-cdata >= cdata_len)
+        return 0;
+    uint16_t tg = 0x0;
+    size_t tgl = 0;
+    tg = *(*p)++;
+    if ((tg & 0x1f) == 0x1f) {
+        tg <<= 8;
+        tg |= *(*p)++;
+    }
+    tgl = *(*p)++;
+    if (tgl == 0x82) {
+        tgl = *(*p)++ << 8;
+        tgl |= *(*p)++;
+    }
+    else if (tgl == 0x81) {
+        tgl = *(*p)++;
+    }
+    if (tag)
+        *tag = tg;
+    if (tag_len)
+        *tag_len = tgl;
+    if (data)
+        *data = *p;
+    *p = *p+tgl;
+    return 1;
+}
+
+bool asn1_find_tag(const uint8_t *data, size_t data_len, uint16_t itag, size_t *tag_len, uint8_t **tag_data) {
+    uint16_t tag = 0x0;
+    uint8_t *p = NULL;
+    while (walk_tlv(data, data_len, &p, &tag, tag_len, tag_data)) {
+        if (itag == tag)
+            return true;
+    }
+    return false;
+}