--- /dev/null
+/*
+ * libopenemv - a library to work with EMV family of smart cards
+ * Copyright (C) 2015 Dmitry Eremin-Solenikov
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "emv_pki.h"
+#include "crypto.h"
+#include "dump.h"
+#include "util.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+
+static const unsigned char empty_tlv_value[] = {};
+static const struct tlv empty_tlv = {.tag = 0x0, .len = 0, .value = empty_tlv_value};
+
+static size_t emv_pki_hash_psn[256] = { 0, 0, 11, 2, 17, 2, };
+
+static unsigned char *emv_pki_decode_message(const struct emv_pk *enc_pk,
+ uint8_t msgtype,
+ size_t *len,
+ const struct tlv *cert_tlv,
+ ... /* A list of tlv pointers, end with NULL */
+ )
+{
+ struct crypto_pk *kcp;
+ unsigned char *data;
+ size_t data_len;
+ va_list vl;
+
+ if (!enc_pk)
+ return NULL;
+
+ if (!cert_tlv) {
+ printf("ERROR: Can't find certificate\n");
+ return NULL;
+ }
+
+ if (cert_tlv->len != enc_pk->mlen) {
+ printf("ERROR: Certificate length (%d) not equal key length (%d)\n", cert_tlv->len, enc_pk->mlen);
+ return NULL;
+ }
+ kcp = crypto_pk_open(enc_pk->pk_algo,
+ enc_pk->modulus, enc_pk->mlen,
+ enc_pk->exp, enc_pk->elen);
+ if (!kcp)
+ return NULL;
+
+ data = crypto_pk_encrypt(kcp, cert_tlv->value, cert_tlv->len, &data_len);
+ crypto_pk_close(kcp);
+
+/* if (true){
+ printf("Recovered data:\n");
+ dump_buffer(data, data_len, stdout, 0);
+ }*/
+
+ if (data[data_len-1] != 0xbc || data[0] != 0x6a || data[1] != msgtype) {
+ printf("ERROR: Certificate format\n");
+ free(data);
+ return NULL;
+ }
+
+ size_t hash_pos = emv_pki_hash_psn[msgtype];
+ if (hash_pos == 0 || hash_pos > data_len){
+ printf("ERROR: Cant get hash position in the certificate\n");
+ free(data);
+ return NULL;
+ }
+
+ struct crypto_hash *ch;
+ ch = crypto_hash_open(data[hash_pos]);
+ if (!ch) {
+ printf("ERROR: Cant do hash\n");
+ free(data);
+ return NULL;
+ }
+
+ size_t hash_len = crypto_hash_get_size(ch);
+ crypto_hash_write(ch, data + 1, data_len - 2 - hash_len);
+
+ va_start(vl, cert_tlv);
+ while (true) {
+ const struct tlv *add_tlv = va_arg(vl, const struct tlv *);
+ if (!add_tlv)
+ break;
+
+ crypto_hash_write(ch, add_tlv->value, add_tlv->len);
+ }
+ va_end(vl);
+
+ if (memcmp(data + data_len - 1 - hash_len, crypto_hash_read(ch), hash_len)) {
+ printf("ERROR: Calculated wrong hash\n");
+ printf("decoded: %s\n",sprint_hex(data + data_len - 1 - hash_len, hash_len));
+ printf("calculated: %s\n",sprint_hex(crypto_hash_read(ch), hash_len));
+ crypto_hash_close(ch);
+ free(data);
+ return NULL;
+ }
+
+ crypto_hash_close(ch);
+
+ *len = data_len - hash_len - 1;
+
+ return data;
+}
+
+static unsigned emv_cn_length(const struct tlv *tlv)
+{
+ int i;
+
+ for (i = 0; i < tlv->len; i++) {
+ unsigned char c = tlv->value[i];
+
+ if (c >> 4 == 0xf)
+ return 2 * i;
+
+ if ((c & 0xf) == 0xf)
+ return 2 * i + 1;
+ }
+
+ return 2 * tlv->len;
+}
+
+static unsigned char emv_cn_get(const struct tlv *tlv, unsigned pos)
+{
+ if (pos > tlv->len * 2)
+ return 0xf;
+
+ unsigned char c = tlv->value[pos / 2];
+
+ if (pos % 2)
+ return c & 0xf;
+ else
+ return c >> 4;
+}
+
+static struct emv_pk *emv_pki_decode_key_ex(const struct emv_pk *enc_pk,
+ unsigned char msgtype,
+ const struct tlv *pan_tlv,
+ const struct tlv *cert_tlv,
+ const struct tlv *exp_tlv,
+ const struct tlv *rem_tlv,
+ const struct tlv *add_tlv,
+ bool showData
+ )
+{
+ size_t pan_length;
+ unsigned char *data;
+ size_t data_len;
+ size_t pk_len;
+
+ if (!cert_tlv || !exp_tlv || !pan_tlv)
+ return NULL;
+
+ if (!rem_tlv)
+ rem_tlv = &empty_tlv;
+
+ if (msgtype == 2)
+ pan_length = 4;
+ else if (msgtype == 4)
+ pan_length = 10;
+ else {
+ printf("ERROR: Message type must be 2 or 4\n");
+ return NULL;
+ }
+
+ data = emv_pki_decode_message(enc_pk, msgtype, &data_len,
+ cert_tlv,
+ rem_tlv,
+ exp_tlv,
+ add_tlv,
+ NULL);
+ if (!data || data_len < 11 + pan_length) {
+ printf("ERROR: Can't decode message\n");
+ return NULL;
+ }
+
+ if (showData){
+ printf("Recovered data:\n");
+ dump_buffer(data, data_len, stdout, 0);
+ }
+
+ /* Perform the rest of checks here */
+
+ struct tlv pan2_tlv = {
+ .tag = 0x5a,
+ .len = pan_length,
+ .value = &data[2],
+ };
+ unsigned pan_len = emv_cn_length(pan_tlv);
+ unsigned pan2_len = emv_cn_length(&pan2_tlv);
+
+ if (((msgtype == 2) && (pan2_len < 4 || pan2_len > pan_len)) ||
+ ((msgtype == 4) && (pan2_len != pan_len))) {
+ printf("ERROR: Invalid PAN lengths\n");
+ free(data);
+
+ return NULL;
+ }
+
+ unsigned i;
+ for (i = 0; i < pan2_len; i++)
+ if (emv_cn_get(pan_tlv, i) != emv_cn_get(&pan2_tlv, i)) {
+ printf("ERROR: PAN data mismatch\n");
+ printf("tlv pan=%s\n", sprint_hex(pan_tlv->value, pan_tlv->len));
+ printf("cert pan=%s\n", sprint_hex(pan2_tlv.value, pan2_tlv.len));
+ free(data);
+
+ return NULL;
+ }
+
+ pk_len = data[9 + pan_length];
+ if (pk_len > data_len - 11 - pan_length + rem_tlv->len) {
+ printf("ERROR: Invalid pk length\n");
+ free(data);
+ return NULL;
+ }
+
+ if (exp_tlv->len != data[10 + pan_length]) {
+ free(data);
+ return NULL;
+ }
+
+ struct emv_pk *pk = emv_pk_new(pk_len, exp_tlv->len);
+
+ memcpy(pk->rid, enc_pk->rid, 5);
+ pk->index = enc_pk->index;
+
+ pk->hash_algo = data[7 + pan_length];
+ pk->pk_algo = data[8 + pan_length];
+ pk->expire = (data[3 + pan_length] << 16) | (data[2 + pan_length] << 8) | 0x31;
+ memcpy(pk->serial, data + 4 + pan_length, 3);
+ memcpy(pk->pan, data + 2, pan_length);
+ memset(pk->pan + pan_length, 0xff, 10 - pan_length);
+
+ memcpy(pk->modulus, data + 11 + pan_length,
+ pk_len < data_len - (11 + pan_length) ?
+ pk_len :
+ data_len - (11 + pan_length));
+ memcpy(pk->modulus + data_len - (11 + pan_length), rem_tlv->value, rem_tlv->len);
+ memcpy(pk->exp, exp_tlv->value, exp_tlv->len);
+
+ free(data);
+
+ return pk;
+}
+
+static struct emv_pk *emv_pki_decode_key(const struct emv_pk *enc_pk,
+ unsigned char msgtype,
+ const struct tlv *pan_tlv,
+ const struct tlv *cert_tlv,
+ const struct tlv *exp_tlv,
+ const struct tlv *rem_tlv,
+ const struct tlv *add_tlv
+ ) {
+ return emv_pki_decode_key_ex(enc_pk, msgtype, pan_tlv, cert_tlv, exp_tlv, rem_tlv, add_tlv, false);
+}
+
+struct emv_pk *emv_pki_recover_issuer_cert(const struct emv_pk *pk, struct tlvdb *db)
+{
+ return emv_pki_decode_key(pk, 2,
+ tlvdb_get(db, 0x5a, NULL),
+ tlvdb_get(db, 0x90, NULL),
+ tlvdb_get(db, 0x9f32, NULL),
+ tlvdb_get(db, 0x92, NULL),
+ NULL);
+}
+
+struct emv_pk *emv_pki_recover_icc_cert(const struct emv_pk *pk, struct tlvdb *db, const struct tlv *sda_tlv)
+{
+ return emv_pki_decode_key(pk, 4,
+ tlvdb_get(db, 0x5a, NULL),
+ tlvdb_get(db, 0x9f46, NULL),
+ tlvdb_get(db, 0x9f47, NULL),
+ tlvdb_get(db, 0x9f48, NULL),
+ sda_tlv);
+}
+
+struct emv_pk *emv_pki_recover_icc_pe_cert(const struct emv_pk *pk, struct tlvdb *db)
+{
+ return emv_pki_decode_key(pk, 4,
+ tlvdb_get(db, 0x5a, NULL),
+ tlvdb_get(db, 0x9f2d, NULL),
+ tlvdb_get(db, 0x9f2e, NULL),
+ tlvdb_get(db, 0x9f2f, NULL),
+ NULL);
+}
+
+struct tlvdb *emv_pki_recover_dac_ex(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *sda_tlv, bool showData)
+{
+ size_t data_len;
+ unsigned char *data = emv_pki_decode_message(enc_pk, 3, &data_len,
+ tlvdb_get(db, 0x93, NULL),
+ sda_tlv,
+ NULL);
+
+ if (!data || data_len < 5)
+ return NULL;
+
+ if (showData){
+ printf("Recovered data:\n");
+ dump_buffer(data, data_len, stdout, 0);
+ }
+
+ struct tlvdb *dac_db = tlvdb_fixed(0x9f45, 2, data+3);
+
+ free(data);
+
+ return dac_db;
+}
+struct tlvdb *emv_pki_recover_dac(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *sda_tlv) {
+ return emv_pki_recover_dac_ex(enc_pk, db, sda_tlv, false);
+}
+
+struct tlvdb *emv_pki_recover_idn(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *dyn_tlv) {
+ return emv_pki_recover_idn_ex(enc_pk, db, dyn_tlv, false);
+}
+
+struct tlvdb *emv_pki_recover_idn_ex(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *dyn_tlv, bool showData)
+{
+ size_t data_len;
+ unsigned char *data = emv_pki_decode_message(enc_pk, 5, &data_len,
+ tlvdb_get(db, 0x9f4b, NULL),
+ dyn_tlv,
+ NULL);
+
+ if (!data || data_len < 3)
+ return NULL;
+
+ if (data[3] < 2 || data[3] > data_len - 3) {
+ free(data);
+ return NULL;
+ }
+
+ if (showData){
+ printf("Recovered data:\n");
+ dump_buffer(data, data_len, stdout, 0);
+ }
+
+ size_t idn_len = data[4];
+ if (idn_len > data[3] - 1) {
+ free(data);
+ return NULL;
+ }
+
+ // 9f4c ICC Dynamic Number
+ struct tlvdb *idn_db = tlvdb_fixed(0x9f4c, idn_len, data + 5);
+
+ free(data);
+
+ return idn_db;
+}
+
+struct tlvdb *emv_pki_recover_atc_ex(const struct emv_pk *enc_pk, const struct tlvdb *db, bool showData)
+{
+ size_t data_len;
+ unsigned char *data = emv_pki_decode_message(enc_pk, 5, &data_len,
+ tlvdb_get(db, 0x9f4b, NULL),
+ tlvdb_get(db, 0x9f37, NULL),
+ tlvdb_get(db, 0x9f02, NULL),
+ tlvdb_get(db, 0x5f2a, NULL),
+ tlvdb_get(db, 0x9f69, NULL),
+ NULL);
+
+ if (!data || data_len < 3)
+ return NULL;
+
+ if (data[3] < 2 || data[3] > data_len - 3) {
+ free(data);
+ return NULL;
+ }
+
+ if (showData){
+ printf("Recovered data:\n");
+ dump_buffer(data, data_len, stdout, 0);
+ }
+
+ size_t idn_len = data[4];
+ if (idn_len > data[3] - 1) {
+ free(data);
+ return NULL;
+ }
+
+ // 9f36 Application Transaction Counter (ATC)
+ struct tlvdb *atc_db = tlvdb_fixed(0x9f36, idn_len, data + 5);
+
+ free(data);
+
+ return atc_db;
+}
+
+static bool tlv_hash(void *data, const struct tlv *tlv, int level, bool is_leaf)
+{
+ struct crypto_hash *ch = data;
+ size_t tag_len;
+ unsigned char *tag;
+
+ if (tlv_is_constructed(tlv))
+ return true;
+
+ if (tlv->tag == 0x9f4b)
+ return true;
+
+ tag = tlv_encode(tlv, &tag_len);
+ crypto_hash_write(ch, tag, tag_len);
+ free(tag);
+
+ return true;
+}
+
+struct tlvdb *emv_pki_perform_cda(const struct emv_pk *enc_pk, const struct tlvdb *db,
+ const struct tlvdb *this_db,
+ const struct tlv *pdol_data_tlv,
+ const struct tlv *crm1_tlv,
+ const struct tlv *crm2_tlv)
+{
+ return emv_pki_perform_cda_ex(enc_pk, db, this_db, pdol_data_tlv, crm1_tlv, crm2_tlv, false);
+}
+struct tlvdb *emv_pki_perform_cda_ex(const struct emv_pk *enc_pk, const struct tlvdb *db,
+ const struct tlvdb *this_db, // AC TLV result
+ const struct tlv *pdol_data_tlv, // PDOL
+ const struct tlv *crm1_tlv, // CDOL1
+ const struct tlv *crm2_tlv, // CDOL2
+ bool showData)
+{
+ const struct tlv *un_tlv = tlvdb_get(db, 0x9f37, NULL);
+ const struct tlv *cid_tlv = tlvdb_get(this_db, 0x9f27, NULL);
+
+ if (!un_tlv || !cid_tlv)
+ return NULL;
+
+ size_t data_len = 0;
+ unsigned char *data = emv_pki_decode_message(enc_pk, 5, &data_len,
+ tlvdb_get(this_db, 0x9f4b, NULL),
+ un_tlv,
+ NULL);
+ if (!data || data_len < 3) {
+ printf("ERROR: can't decode message. len %d\n", data_len);
+ return NULL;
+ }
+
+ if (showData){
+ printf("Recovered data:\n");
+ dump_buffer(data, data_len, stdout, 0);
+ }
+
+ if (data[3] < 30 || data[3] > data_len - 4) {
+ printf("ERROR: Invalid data length\n");
+ free(data);
+ return NULL;
+ }
+
+ if (!cid_tlv || cid_tlv->len != 1 || cid_tlv->value[0] != data[5 + data[4]]) {
+ printf("ERROR: CID mismatch\n");
+ free(data);
+ return NULL;
+ }
+
+ struct crypto_hash *ch;
+ ch = crypto_hash_open(enc_pk->hash_algo);
+ if (!ch) {
+ printf("ERROR: can't create hash\n");
+ free(data);
+ return NULL;
+ }
+
+ if (pdol_data_tlv)
+ crypto_hash_write(ch, pdol_data_tlv->value, pdol_data_tlv->len);
+ if (crm1_tlv)
+ crypto_hash_write(ch, crm1_tlv->value, crm1_tlv->len);
+ if (crm2_tlv)
+ crypto_hash_write(ch, crm2_tlv->value, crm2_tlv->len);
+
+ tlvdb_visit(this_db, tlv_hash, ch, 0);
+
+ if (memcmp(data + 5 + data[4] + 1 + 8, crypto_hash_read(ch), 20)) {
+ printf("ERROR: calculated hash error\n");
+ crypto_hash_close(ch);
+ free(data);
+ return NULL;
+ }
+ crypto_hash_close(ch);
+
+ size_t idn_len = data[4];
+ if (idn_len > data[3] - 1) {
+ printf("ERROR: Invalid IDN length\n");
+ free(data);
+ return NULL;
+ }
+
+ struct tlvdb *idn_db = tlvdb_fixed(0x9f4c, idn_len, data + 5);
+ free(data);
+
+ return idn_db;
+}
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