proxmark3/client/emv/emv_pki.c
2019-01-09 21:05:52 +02:00

588 lines
14 KiB
C

/*
* 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 bool strictExecution = true;
void PKISetStrictExecution(bool se) {
strictExecution = se;
}
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,
int tlv_count,
... /* A list of tlv pointers */
)
{
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 (%zu) not equal key length (%zu)\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, tlv_count);
for (int i = 0; i < tlv_count; i++) {
const struct tlv *add_tlv = va_arg(vl, const struct tlv *);
if (!add_tlv)
continue;
crypto_hash_write(ch, add_tlv->value, add_tlv->len);
}
va_end(vl);
uint8_t hash[hash_len];
memset(hash, 0, hash_len);
memcpy(hash, crypto_hash_read(ch), hash_len);
if (memcmp(data + data_len - 1 - hash_len, hash, 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(hash, hash_len));
if (strictExecution) {
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,
const struct tlv *sdatl_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,
5,
rem_tlv,
exp_tlv,
add_tlv,
sdatl_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,
const struct tlv *sdatl_tlv
) {
return emv_pki_decode_key_ex(enc_pk, msgtype, pan_tlv, cert_tlv, exp_tlv, rem_tlv, add_tlv, sdatl_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,
NULL);
}
struct emv_pk *emv_pki_recover_icc_cert(const struct emv_pk *pk, struct tlvdb *db, const struct tlv *sda_tlv)
{
size_t sdatl_len;
unsigned char *sdatl = emv_pki_sdatl_fill(db, &sdatl_len);
struct tlv sda_tdata = {
.tag = 0x00, // dummy tag
.len = sdatl_len,
.value = sdatl
};
struct emv_pk *res = 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,
&sda_tdata);
free(sdatl); // malloc here: emv_pki_sdatl_fill
return res;
}
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,
NULL);
}
unsigned char *emv_pki_sdatl_fill(const struct tlvdb *db, size_t *sdatl_len) {
uint8_t buf[2048] = {0};
size_t len = 0;
*sdatl_len = 0;
const struct tlv *sda_tl = tlvdb_get(db, 0x9f4a, NULL);
if (!sda_tl || sda_tl->len <= 0)
return NULL;
for (int i = 0; i < sda_tl->len; i++) {
uint32_t tag = sda_tl->value[i]; // here may be multibyte, but now not
const struct tlv *elm = tlvdb_get(db, tag, NULL);
if (elm) {
memcpy(&buf[len], elm->value, elm->len);
len += elm->len;
}
}
if (len) {
*sdatl_len = len;
unsigned char *value = malloc(len);
memcpy(value, buf, len);
return value;
}
return 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;
// Static Data Authentication Tag List
size_t sdatl_len;
unsigned char *sdatl = emv_pki_sdatl_fill(db, &sdatl_len);
struct tlv sda_tdata = {
.tag = 0x00, // dummy tag
.len = sdatl_len,
.value = sdatl
};
unsigned char *data = emv_pki_decode_message(enc_pk, 3, &data_len,
tlvdb_get(db, 0x93, NULL),
3,
sda_tlv,
&sda_tdata,
NULL);
free(sdatl); // malloc here: emv_pki_sdatl_fill
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),
2,
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),
5,
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),
2,
un_tlv,
NULL);
if (!data || data_len < 3) {
printf("ERROR: can't decode message. len %zu\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;
}