mirror of
https://github.com/RfidResearchGroup/proxmark3.git
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638 lines
No EOL
21 KiB
C
638 lines
No EOL
21 KiB
C
/*-
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* Copyright (C) 2010, Romain Tartiere.
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*
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* This program is free software: you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or (at your
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* option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU Lesser 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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* $Id$
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*/
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/*
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* This implementation was written based on information provided by the
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* following documents:
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*
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* NIST Special Publication 800-38B
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* Recommendation for Block Cipher Modes of Operation: The CMAC Mode for Authentication
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* May 2005
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*/
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#include "desfire_crypto.h"
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static void xor (const uint8_t *ivect, uint8_t *data, const size_t len);
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static size_t key_macing_length (desfirekey_t key);
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// iceman, see memxor inside string.c, dest/src swapped..
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static void xor (const uint8_t *ivect, uint8_t *data, const size_t len) {
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for (size_t i = 0; i < len; i++) {
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data[i] ^= ivect[i];
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}
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}
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void cmac_generate_subkeys ( desfirekey_t key) {
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int kbs = key_block_size (key);
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const uint8_t R = (kbs == 8) ? 0x1B : 0x87;
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uint8_t l[kbs];
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memset (l, 0, kbs);
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uint8_t ivect[kbs];
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memset (ivect, 0, kbs);
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mifare_cypher_blocks_chained (NULL, key, ivect, l, kbs, MCD_RECEIVE, MCO_ENCYPHER);
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bool xor = false;
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// Used to compute CMAC on complete blocks
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memcpy (key->cmac_sk1, l, kbs);
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xor = l[0] & 0x80;
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lsl (key->cmac_sk1, kbs);
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if (xor)
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key->cmac_sk1[kbs-1] ^= R;
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// Used to compute CMAC on the last block if non-complete
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memcpy (key->cmac_sk2, key->cmac_sk1, kbs);
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xor = key->cmac_sk1[0] & 0x80;
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lsl (key->cmac_sk2, kbs);
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if (xor)
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key->cmac_sk2[kbs-1] ^= R;
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}
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void cmac (const desfirekey_t key, uint8_t *ivect, const uint8_t *data, size_t len, uint8_t *cmac) {
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int kbs = key_block_size (key);
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uint8_t *buffer = malloc (padded_data_length (len, kbs));
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memcpy (buffer, data, len);
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if ((!len) || (len % kbs)) {
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buffer[len++] = 0x80;
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while (len % kbs) {
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buffer[len++] = 0x00;
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}
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xor (key->cmac_sk2, buffer + len - kbs, kbs);
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} else {
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xor (key->cmac_sk1, buffer + len - kbs, kbs);
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}
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mifare_cypher_blocks_chained (NULL, key, ivect, buffer, len, MCD_SEND, MCO_ENCYPHER);
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memcpy (cmac, ivect, kbs);
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free(buffer);
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}
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size_t key_block_size (const desfirekey_t key) {
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size_t block_size = 8;
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switch (key->type) {
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case T_DES:
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case T_3DES:
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case T_3K3DES:
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block_size = 8;
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break;
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case T_AES:
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block_size = 16;
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break;
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}
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return block_size;
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}
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/*
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* Size of MACing produced with the key.
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*/
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static size_t key_macing_length (const desfirekey_t key) {
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size_t mac_length = MAC_LENGTH;
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switch (key->type) {
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case T_DES:
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case T_3DES:
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mac_length = MAC_LENGTH;
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break;
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case T_3K3DES:
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case T_AES:
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mac_length = CMAC_LENGTH;
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break;
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}
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return mac_length;
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}
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/*
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* Size required to store nbytes of data in a buffer of size n*block_size.
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*/
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size_t padded_data_length (const size_t nbytes, const size_t block_size) {
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if ((!nbytes) || (nbytes % block_size))
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return ((nbytes / block_size) + 1) * block_size;
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else
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return nbytes;
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}
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/*
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* Buffer size required to MAC nbytes of data
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*/
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size_t maced_data_length (const desfirekey_t key, const size_t nbytes) {
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return nbytes + key_macing_length (key);
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}
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/*
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* Buffer size required to encipher nbytes of data and a two bytes CRC.
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*/
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size_t enciphered_data_length (const desfiretag_t tag, const size_t nbytes, int communication_settings) {
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size_t crc_length = 0;
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if (!(communication_settings & NO_CRC)) {
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switch (DESFIRE(tag)->authentication_scheme) {
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case AS_LEGACY:
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crc_length = 2;
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break;
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case AS_NEW:
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crc_length = 4;
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break;
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}
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}
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size_t block_size = DESFIRE(tag)->session_key ? key_block_size (DESFIRE(tag)->session_key) : 1;
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return padded_data_length (nbytes + crc_length, block_size);
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}
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void* mifare_cryto_preprocess_data (desfiretag_t tag, void *data, size_t *nbytes, size_t offset, int communication_settings) {
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uint8_t *res = data;
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uint8_t mac[4];
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size_t edl;
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bool append_mac = true;
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desfirekey_t key = DESFIRE(tag)->session_key;
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if (!key)
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return data;
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switch (communication_settings & MDCM_MASK) {
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case MDCM_PLAIN:
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if (AS_LEGACY == DESFIRE(tag)->authentication_scheme)
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break;
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/*
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* When using new authentication methods, PLAIN data transmission from
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* the PICC to the PCD are CMACed, so we have to maintain the
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* cryptographic initialisation vector up-to-date to check data
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* integrity later.
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*
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* The only difference with CMACed data transmission is that the CMAC
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* is not apended to the data send by the PCD to the PICC.
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*/
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append_mac = false;
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/* pass through */
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case MDCM_MACED:
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switch (DESFIRE(tag)->authentication_scheme) {
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case AS_LEGACY:
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if (!(communication_settings & MAC_COMMAND))
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break;
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/* pass through */
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edl = padded_data_length (*nbytes - offset, key_block_size (DESFIRE(tag)->session_key)) + offset;
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// Fill in the crypto buffer with data ...
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memcpy (res, data, *nbytes);
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// ... and 0 padding
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memset (res + *nbytes, 0, edl - *nbytes);
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mifare_cypher_blocks_chained (tag, NULL, NULL, res + offset, edl - offset, MCD_SEND, MCO_ENCYPHER);
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memcpy (mac, res + edl - 8, 4);
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// Copy again provided data (was overwritten by mifare_cypher_blocks_chained)
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memcpy (res, data, *nbytes);
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if (!(communication_settings & MAC_COMMAND))
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break;
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// Append MAC
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size_t bla = maced_data_length (DESFIRE(tag)->session_key, *nbytes - offset) + offset;
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bla++;
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memcpy (res + *nbytes, mac, 4);
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*nbytes += 4;
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break;
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case AS_NEW:
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if (!(communication_settings & CMAC_COMMAND))
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break;
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cmac (key, DESFIRE (tag)->ivect, res, *nbytes, DESFIRE (tag)->cmac);
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if (append_mac) {
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size_t len = maced_data_length (key, *nbytes);
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++len;
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memcpy (res, data, *nbytes);
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memcpy (res + *nbytes, DESFIRE (tag)->cmac, CMAC_LENGTH);
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*nbytes += CMAC_LENGTH;
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}
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break;
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}
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break;
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case MDCM_ENCIPHERED:
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/* |<-------------- data -------------->|
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* |<--- offset -->| |
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* +---------------+--------------------+-----+---------+
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* | CMD + HEADERS | DATA TO BE SECURED | CRC | PADDING |
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* +---------------+--------------------+-----+---------+ ----------------
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* | |<~~~~v~~~~~~~~~~~~~>| ^ | | (DES / 3DES)
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* | | `---- crc16() ----' | |
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* | | | ^ | | ----- *or* -----
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* |<~~~~~~~~~~~~~~~~~~~~v~~~~~~~~~~~~~>| ^ | | (3K3DES / AES)
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* | `---- crc32() ----' | |
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* | | ---- *then* ----
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* |<---------------------------------->|
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* encypher()/decypher()
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*/
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if (!(communication_settings & ENC_COMMAND))
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break;
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edl = enciphered_data_length (tag, *nbytes - offset, communication_settings) + offset;
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// Fill in the crypto buffer with data ...
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memcpy (res, data, *nbytes);
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if (!(communication_settings & NO_CRC)) {
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// ... CRC ...
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switch (DESFIRE (tag)->authentication_scheme) {
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case AS_LEGACY:
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AddCrc14A(res + offset, *nbytes - offset);
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*nbytes += 2;
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break;
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case AS_NEW:
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crc32_append (res, *nbytes);
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*nbytes += 4;
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break;
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}
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}
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// ... and padding
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memset (res + *nbytes, 0, edl - *nbytes);
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*nbytes = edl;
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mifare_cypher_blocks_chained (tag, NULL, NULL, res + offset, *nbytes - offset, MCD_SEND, (AS_NEW == DESFIRE(tag)->authentication_scheme) ? MCO_ENCYPHER : MCO_DECYPHER);
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break;
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default:
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*nbytes = -1;
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res = NULL;
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break;
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}
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return res;
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}
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void* mifare_cryto_postprocess_data (desfiretag_t tag, void *data, size_t *nbytes, int communication_settings)
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{
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void *res = data;
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size_t edl;
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void *edata = NULL;
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uint8_t first_cmac_byte = 0x00;
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desfirekey_t key = DESFIRE(tag)->session_key;
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if (!key)
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return data;
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// Return directly if we just have a status code.
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if (1 == *nbytes)
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return res;
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switch (communication_settings & MDCM_MASK) {
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case MDCM_PLAIN:
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if (AS_LEGACY == DESFIRE(tag)->authentication_scheme)
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break;
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/* pass through */
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case MDCM_MACED:
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switch (DESFIRE (tag)->authentication_scheme) {
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case AS_LEGACY:
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if (communication_settings & MAC_VERIFY) {
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*nbytes -= key_macing_length (key);
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if (*nbytes <= 0) {
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*nbytes = -1;
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res = NULL;
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#ifdef WITH_DEBUG
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Dbprintf ("No room for MAC!");
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#endif
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break;
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}
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edl = enciphered_data_length (tag, *nbytes - 1, communication_settings);
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edata = malloc (edl);
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memcpy (edata, data, *nbytes - 1);
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memset ((uint8_t *)edata + *nbytes - 1, 0, edl - *nbytes + 1);
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mifare_cypher_blocks_chained (tag, NULL, NULL, edata, edl, MCD_SEND, MCO_ENCYPHER);
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if (0 != memcmp ((uint8_t *)data + *nbytes - 1, (uint8_t *)edata + edl - 8, 4)) {
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#ifdef WITH_DEBUG
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Dbprintf ("MACing not verified");
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hexdump ((uint8_t *)data + *nbytes - 1, key_macing_length (key), "Expect ", 0);
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hexdump ((uint8_t *)edata + edl - 8, key_macing_length (key), "Actual ", 0);
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#endif
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DESFIRE (tag)->last_pcd_error = CRYPTO_ERROR;
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*nbytes = -1;
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res = NULL;
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}
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}
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break;
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case AS_NEW:
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if (!(communication_settings & CMAC_COMMAND))
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break;
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if (communication_settings & CMAC_VERIFY) {
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if (*nbytes < 9) {
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*nbytes = -1;
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res = NULL;
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break;
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}
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first_cmac_byte = ((uint8_t *)data)[*nbytes - 9];
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((uint8_t *)data)[*nbytes - 9] = ((uint8_t *)data)[*nbytes-1];
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}
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int n = (communication_settings & CMAC_VERIFY) ? 8 : 0;
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cmac (key, DESFIRE (tag)->ivect, ((uint8_t *)data), *nbytes - n, DESFIRE (tag)->cmac);
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if (communication_settings & CMAC_VERIFY) {
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((uint8_t *)data)[*nbytes - 9] = first_cmac_byte;
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if (0 != memcmp (DESFIRE (tag)->cmac, (uint8_t *)data + *nbytes - 9, 8)) {
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#ifdef WITH_DEBUG
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Dbprintf ("CMAC NOT verified :-(");
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hexdump ((uint8_t *)data + *nbytes - 9, 8, "Expect ", 0);
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hexdump (DESFIRE (tag)->cmac, 8, "Actual ", 0);
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#endif
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DESFIRE (tag)->last_pcd_error = CRYPTO_ERROR;
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*nbytes = -1;
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res = NULL;
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} else {
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*nbytes -= 8;
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}
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}
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break;
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}
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free (edata);
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break;
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case MDCM_ENCIPHERED:
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(*nbytes)--;
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bool verified = false;
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int crc_pos = 0x00;
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int end_crc_pos = 0x00;
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uint8_t x;
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/*
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* AS_LEGACY:
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* ,-----------------+-------------------------------+--------+
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* \ BLOCK n-1 | BLOCK n | STATUS |
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* / PAYLOAD | CRC0 | CRC1 | 0x80? | 0x000000000000 | 0x9100 |
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* `-----------------+-------------------------------+--------+
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*
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* <------------ DATA ------------>
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* FRAME = PAYLOAD + CRC(PAYLOAD) + PADDING
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*
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* AS_NEW:
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* ,-------------------------------+-----------------------------------------------+--------+
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* \ BLOCK n-1 | BLOCK n | STATUS |
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* / PAYLOAD | CRC0 | CRC1 | CRC2 | CRC3 | 0x80? | 0x0000000000000000000000000000 | 0x9100 |
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* `-------------------------------+-----------------------------------------------+--------+
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* <----------------------------------- DATA ------------------------------------->|
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*
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* <----------------- DATA ---------------->
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* FRAME = PAYLOAD + CRC(PAYLOAD + STATUS) + PADDING + STATUS
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* `------------------'
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*/
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mifare_cypher_blocks_chained (tag, NULL, NULL, res, *nbytes, MCD_RECEIVE, MCO_DECYPHER);
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/*
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* Look for the CRC and ensure it is followed by NULL padding. We
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* can't start by the end because the CRC is supposed to be 0 when
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* verified, and accumulating 0's in it should not change it.
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*/
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switch (DESFIRE (tag)->authentication_scheme) {
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case AS_LEGACY:
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crc_pos = *nbytes - 8 - 1; // The CRC can be over two blocks
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if (crc_pos < 0) {
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/* Single block */
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crc_pos = 0;
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}
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break;
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case AS_NEW:
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/* Move status between payload and CRC */
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res = DESFIRE (tag)->crypto_buffer;
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memcpy (res, data, *nbytes);
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crc_pos = (*nbytes) - 16 - 3;
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if (crc_pos < 0) {
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/* Single block */
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crc_pos = 0;
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}
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memcpy ((uint8_t *)res + crc_pos + 1, (uint8_t *)res + crc_pos, *nbytes - crc_pos);
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((uint8_t *)res)[crc_pos] = 0x00;
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crc_pos++;
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*nbytes += 1;
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break;
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}
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do {
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uint16_t crc16 =0x00;
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uint32_t crc;
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switch (DESFIRE (tag)->authentication_scheme) {
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case AS_LEGACY:
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AddCrc14A( (uint8_t*)res, end_crc_pos);
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end_crc_pos = crc_pos + 2;
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//
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crc = crc16;
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break;
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case AS_NEW:
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end_crc_pos = crc_pos + 4;
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crc32_ex (res, end_crc_pos, (uint8_t *)&crc);
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break;
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}
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if (!crc) {
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verified = true;
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for (int n = end_crc_pos; n < *nbytes - 1; n++) {
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uint8_t byte = ((uint8_t *)res)[n];
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if (!( (0x00 == byte) || ((0x80 == byte) && (n == end_crc_pos)) ))
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verified = false;
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}
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}
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if (verified) {
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*nbytes = crc_pos;
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switch (DESFIRE (tag)->authentication_scheme) {
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case AS_LEGACY:
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((uint8_t *)data)[(*nbytes)++] = 0x00;
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break;
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case AS_NEW:
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/* The status byte was already before the CRC */
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break;
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}
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} else {
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switch (DESFIRE (tag)->authentication_scheme) {
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case AS_LEGACY:
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break;
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case AS_NEW:
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x = ((uint8_t *)res)[crc_pos - 1];
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((uint8_t *)res)[crc_pos - 1] = ((uint8_t *)res)[crc_pos];
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((uint8_t *)res)[crc_pos] = x;
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break;
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}
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crc_pos++;
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}
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} while (!verified && (end_crc_pos < *nbytes));
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if (!verified) {
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#ifdef WITH_DEBUG
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/* FIXME In some configurations, the file is transmitted PLAIN */
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Dbprintf("CRC not verified in decyphered stream");
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#endif
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DESFIRE (tag)->last_pcd_error = CRYPTO_ERROR;
|
|
*nbytes = -1;
|
|
res = NULL;
|
|
}
|
|
|
|
break;
|
|
default:
|
|
Dbprintf("Unknown communication settings");
|
|
*nbytes = -1;
|
|
res = NULL;
|
|
break;
|
|
|
|
}
|
|
return res;
|
|
}
|
|
|
|
|
|
void mifare_cypher_single_block (desfirekey_t key, uint8_t *data, uint8_t *ivect, MifareCryptoDirection direction, MifareCryptoOperation operation, size_t block_size)
|
|
{
|
|
uint8_t ovect[MAX_CRYPTO_BLOCK_SIZE];
|
|
|
|
if (direction == MCD_SEND) {
|
|
xor (ivect, data, block_size);
|
|
} else {
|
|
memcpy (ovect, data, block_size);
|
|
}
|
|
|
|
uint8_t edata[MAX_CRYPTO_BLOCK_SIZE];
|
|
|
|
switch (key->type) {
|
|
case T_DES:
|
|
switch (operation) {
|
|
case MCO_ENCYPHER:
|
|
//DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_ENCRYPT);
|
|
des_enc(edata, data, key->data);
|
|
break;
|
|
case MCO_DECYPHER:
|
|
//DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_DECRYPT);
|
|
des_dec(edata, data, key->data);
|
|
break;
|
|
}
|
|
break;
|
|
case T_3DES:
|
|
switch (operation) {
|
|
case MCO_ENCYPHER:
|
|
// DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_ENCRYPT);
|
|
// DES_ecb_encrypt ((DES_cblock *) edata, (DES_cblock *) data, &(key->ks2), DES_DECRYPT);
|
|
// DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_ENCRYPT);
|
|
tdes_enc(edata,data, key->data);
|
|
break;
|
|
case MCO_DECYPHER:
|
|
// DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_DECRYPT);
|
|
// DES_ecb_encrypt ((DES_cblock *) edata, (DES_cblock *) data, &(key->ks2), DES_ENCRYPT);
|
|
// DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_DECRYPT);
|
|
tdes_dec(data, edata, key->data);
|
|
break;
|
|
}
|
|
break;
|
|
case T_3K3DES:
|
|
switch (operation) {
|
|
case MCO_ENCYPHER:
|
|
tdes_enc(edata,data, key->data);
|
|
// DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_ENCRYPT);
|
|
// DES_ecb_encrypt ((DES_cblock *) edata, (DES_cblock *) data, &(key->ks2), DES_DECRYPT);
|
|
// DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks3), DES_ENCRYPT);
|
|
break;
|
|
case MCO_DECYPHER:
|
|
tdes_dec(data, edata, key->data);
|
|
// DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks3), DES_DECRYPT);
|
|
// DES_ecb_encrypt ((DES_cblock *) edata, (DES_cblock *) data, &(key->ks2), DES_ENCRYPT);
|
|
// DES_ecb_encrypt ((DES_cblock *) data, (DES_cblock *) edata, &(key->ks1), DES_DECRYPT);
|
|
break;
|
|
}
|
|
break;
|
|
case T_AES:
|
|
switch (operation)
|
|
{
|
|
case MCO_ENCYPHER:
|
|
{
|
|
AesCtx ctx;
|
|
AesCtxIni(&ctx, ivect, key->data, KEY128,CBC);
|
|
AesEncrypt(&ctx, data, edata, sizeof(edata) );
|
|
break;
|
|
}
|
|
case MCO_DECYPHER:
|
|
{
|
|
AesCtx ctx;
|
|
AesCtxIni(&ctx, ivect, key->data, KEY128,CBC);
|
|
AesDecrypt(&ctx, edata, data, sizeof(edata));
|
|
break;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
memcpy (data, edata, block_size);
|
|
|
|
if (direction == MCD_SEND) {
|
|
memcpy (ivect, data, block_size);
|
|
} else {
|
|
xor (ivect, data, block_size);
|
|
memcpy (ivect, ovect, block_size);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This function performs all CBC cyphering / deciphering.
|
|
*
|
|
* The tag argument may be NULL, in which case both key and ivect shall be set.
|
|
* When using the tag session_key and ivect for processing data, these
|
|
* arguments should be set to NULL.
|
|
*
|
|
* Because the tag may contain additional data, one may need to call this
|
|
* function with tag, key and ivect defined.
|
|
*/
|
|
void mifare_cypher_blocks_chained (desfiretag_t tag, desfirekey_t key, uint8_t *ivect, uint8_t *data, size_t data_size, MifareCryptoDirection direction, MifareCryptoOperation operation) {
|
|
size_t block_size;
|
|
|
|
if (tag) {
|
|
if (!key)
|
|
key = DESFIRE (tag)->session_key;
|
|
if (!ivect)
|
|
ivect = DESFIRE (tag)->ivect;
|
|
|
|
switch (DESFIRE (tag)->authentication_scheme) {
|
|
case AS_LEGACY:
|
|
memset (ivect, 0, MAX_CRYPTO_BLOCK_SIZE);
|
|
break;
|
|
case AS_NEW:
|
|
break;
|
|
}
|
|
}
|
|
|
|
block_size = key_block_size (key);
|
|
|
|
size_t offset = 0;
|
|
while (offset < data_size) {
|
|
mifare_cypher_single_block (key, data + offset, ivect, direction, operation, block_size);
|
|
offset += block_size;
|
|
}
|
|
} |