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add mac length and fix encode/decode

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This commit is contained in:
merlokk 2021-07-07 16:17:35 +03:00
commit 0f0ef4435e
2 changed files with 51 additions and 9 deletions
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56
client/src/mifare/desfirecrypto.c
View file

@ -26,6 +26,7 @@
#include "ui.h"
#include "aes.h"
#include "des.h"
#include <mbedtls/cmac.h>
#include "crc.h"
#include "crc16.h" // crc16 ccitt
#include "crc32.h"
@ -87,6 +88,25 @@ bool DesfireIsAuthenticated(DesfireContext *dctx) {
return dctx->secureChannel != DACNone;
}
size_t DesfireGetMACLength(DesfireContext *ctx) {
size_t mac_length = MAC_LENGTH;
switch (ctx->secureChannel) {
case DACNone:
mac_length = 0;
break;
case DACd40:
mac_length = 4;
break;
case DACEV1:
mac_length = 8;
break;
case DACEV2:
mac_length = 8;
break;
}
return mac_length;
}
static void DesfireCryptoEncDecSingleBlock(uint8_t *key, DesfireCryptoAlgorythm keyType, uint8_t *data, uint8_t *dstdata, uint8_t *ivect, bool dir_to_send, bool encode) {
size_t block_size = desfire_get_key_block_length(keyType);
uint8_t sdata[MAX_CRYPTO_BLOCK_SIZE] = {0};
@ -146,33 +166,49 @@ static void DesfireCryptoEncDecSingleBlock(uint8_t *key, DesfireCryptoAlgorythm
memcpy(dstdata, edata, block_size);
if (dir_to_send) {
memcpy(ivect, sdata, block_size);
memcpy(ivect, edata, block_size);
} else {
memcpy(ivect, data, block_size);
}
}
void DesfireCryptoEncDec(DesfireContext *ctx, bool use_session_key, uint8_t *srcdata, size_t srcdatalen, uint8_t *dstdata, bool encode) {
void DesfireCryptoEncDecEx(DesfireContext *ctx, bool use_session_key, uint8_t *srcdata, size_t srcdatalen, uint8_t *dstdata, bool encode, uint8_t *iv) {
uint8_t data[1024] = {0};
uint8_t xiv[DESFIRE_MAX_CRYPTO_BLOCK_SIZE] = {0};
if (ctx->secureChannel == DACd40)
memset(ctx->IV, 0, DESFIRE_MAX_CRYPTO_BLOCK_SIZE);
size_t block_size = desfire_get_key_block_length(ctx->keyType);
if (iv == NULL)
memcpy(xiv, ctx->IV, block_size);
else
memcpy(xiv, iv, block_size);
size_t offset = 0;
while (offset < srcdatalen) {
//mifare_cypher_single_block(key, data + offset, ivect, direction, operation, block_size);
if (use_session_key)
DesfireCryptoEncDecSingleBlock(ctx->sessionKeyMAC, ctx->keyType, srcdata + offset, data, ctx->IV, encode, encode);
DesfireCryptoEncDecSingleBlock(ctx->sessionKeyMAC, ctx->keyType, srcdata + offset, data, xiv, encode, encode);
else
DesfireCryptoEncDecSingleBlock(ctx->key, ctx->keyType, srcdata + offset, data, ctx->IV, encode, encode);
DesfireCryptoEncDecSingleBlock(ctx->key, ctx->keyType, srcdata + offset, data, xiv, encode, encode);
offset += block_size;
}
if (iv == NULL)
memcpy(ctx->IV, xiv, block_size);
else
memcpy(iv, xiv, block_size);
if (dstdata)
memcpy(dstdata, data, srcdatalen);
}
void DesfireCryptoEncDec(DesfireContext *ctx, bool use_session_key, uint8_t *srcdata, size_t srcdatalen, uint8_t *dstdata, bool encode) {
DesfireCryptoEncDecEx(ctx, use_session_key, srcdata, srcdatalen, dstdata, encode, NULL);
}
static void DesfireCMACGenerateSubkeys(DesfireContext *ctx, uint8_t *sk1, uint8_t *sk2) {
int kbs = desfire_get_key_block_length(ctx->keyType);
const uint8_t R = (kbs == 8) ? 0x1B : 0x87;
@ -184,7 +220,7 @@ static void DesfireCMACGenerateSubkeys(DesfireContext *ctx, uint8_t *sk1, uint8_
memset(ivect, 0, kbs);
//mifare_cypher_blocks_chained(NULL, key, ivect, l, kbs, MCD_SEND, MCO_ENCYPHER);
DesfireCryptoEncDec(ctx, true, l, kbs, l, true);
DesfireCryptoEncDecEx(ctx, true, l, kbs, l, true, ivect);
//PrintAndLogEx(INFO, "i: %s", sprint_hex(l, kbs));
bool txor = false;
@ -211,14 +247,15 @@ void DesfireCryptoCMAC(DesfireContext *ctx, uint8_t *data, size_t len, uint8_t *
if (kbs == 0)
return;
uint8_t buffer[kbs];
memset(buffer, 0, kbs);
uint8_t buffer[padded_data_length(len, kbs)];
memset(buffer, 0, sizeof(buffer));
uint8_t sk1[DESFIRE_MAX_CRYPTO_BLOCK_SIZE] = {0};
uint8_t sk2[DESFIRE_MAX_CRYPTO_BLOCK_SIZE] = {0};
DesfireCMACGenerateSubkeys(ctx, sk1, sk2);
memcpy(buffer, data, len);
PrintAndLogEx(INFO, "key: %s", sprint_hex(ctx->sessionKeyMAC, 24));
PrintAndLogEx(INFO, "sk1: %s", sprint_hex(sk1, 8));
PrintAndLogEx(INFO, "sk2: %s", sprint_hex(sk2, 8));
@ -227,15 +264,18 @@ PrintAndLogEx(INFO, "sk2: %s", sprint_hex(sk2, 8));
while (len % kbs) {
buffer[len++] = 0x00;
}
PrintAndLogEx(INFO, "befode xor sk1: %s", sprint_hex(buffer, len));
bin_xor(buffer + len - kbs, sk2, kbs);
} else {
PrintAndLogEx(INFO, "befode xor sk2: %s", sprint_hex(buffer, len));
bin_xor(buffer + len - kbs, sk1, kbs);
}
PrintAndLogEx(INFO, "cbuf: %s", sprint_hex(buffer, len));
PrintAndLogEx(INFO, "iv: %s", sprint_hex(ctx->IV, kbs));
//mifare_cypher_blocks_chained(NULL, key, ivect, buffer, len, MCD_SEND, MCO_ENCYPHER);
DesfireCryptoEncDec(ctx, true, buffer, len, NULL, true);
memcpy(cmac, ctx->IV, kbs);
}

2
client/src/mifare/desfirecrypto.h
View file

@ -91,9 +91,11 @@ void DesfireSetCommandSet(DesfireContext *ctx, DesfireCommandSet cmdSet);
void DesfireSetCommMode(DesfireContext *ctx, DesfireCommunicationMode commMode);
void DesfireSetKdf(DesfireContext *ctx, uint8_t kdfAlgo, uint8_t *kdfInput, uint8_t kdfInputLen);
bool DesfireIsAuthenticated(DesfireContext *dctx);
size_t DesfireGetMACLength(DesfireContext *ctx);
void DesfireCryptoEncDec(DesfireContext *ctx, bool use_session_key, uint8_t *srcdata, size_t srcdatalen, uint8_t *dstdata, bool encode);
void DesfireCryptoEncDecEx(DesfireContext *ctx, bool use_session_key, uint8_t *srcdata, size_t srcdatalen, uint8_t *dstdata, bool encode, uint8_t *iv);
void DesfireCryptoCMAC(DesfireContext *ctx, uint8_t *srcdata, size_t srcdatalen, uint8_t *cmac);