RfidResearchGroup/proxmark3
1
1
Fork 0
mirror of https://github.com/RfidResearchGroup/proxmark3.git synced 2025-02-02 13:28:14 +08:00
Code Issues Projects Releases Packages Wiki Activity

Fix Gallagher data decoding & CRC checks

Browse source 
Descramble function was re-scrambling the data
Skip constant magic prefix `7FEA` to get correct data to decode
Fix offsets & bitmasks to correctly decode card and region codes
Fix CRC refin & refout parameters (both now false)
This commit is contained in:
DarkMatterMatt 2021-02-10 15:47:14 +13:00
parent abbbbcebc9
commit a4da1476b6
2 changed files with 36 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

44
client/src/cmdlfgallagher.c
View file

@ -29,8 +29,8 @@
static int CmdHelp(const char *Cmd);
static void descramble(uint8_t *arr, uint8_t len) {
/*
static void scramble(uint8_t *arr, uint8_t len) {
uint8_t lut[] = {
0xa3, 0xb0, 0x80, 0xc6, 0xb2, 0xf4, 0x5c, 0x6c, 0x81, 0xf1, 0xbb, 0xeb, 0x55, 0x67, 0x3c, 0x05,
0x1a, 0x0e, 0x61, 0xf6, 0x22, 0xce, 0xaa, 0x8f, 0xbd, 0x3b, 0x1f, 0x5e, 0x44, 0x04, 0x51, 0x2e,
@ -54,6 +54,32 @@ static void descramble(uint8_t *arr, uint8_t len) {
arr[i] = lut[arr[i]];
}
}
*/
static void descramble(uint8_t *arr, uint8_t len) {
uint8_t lut[] = {
0x2f, 0x6e, 0xdd, 0xdf, 0x1d, 0x0f, 0xb0, 0x76, 0xad, 0xaf, 0x7f, 0xbb, 0x77, 0x85, 0x11, 0x6d,
0xf4, 0xd2, 0x84, 0x42, 0xeb, 0xf7, 0x34, 0x55, 0x4a, 0x3a, 0x10, 0x71, 0xe7, 0xa1, 0x62, 0x1a,
0x3e, 0x4c, 0x14, 0xd3, 0x5e, 0xb2, 0x7d, 0x56, 0xbc, 0x27, 0x82, 0x60, 0xe3, 0xae, 0x1f, 0x9b,
0xaa, 0x2b, 0x95, 0x49, 0x73, 0xe1, 0x92, 0x79, 0x91, 0x38, 0x6c, 0x19, 0x0e, 0xa9, 0xe2, 0x8d,
0x66, 0xc7, 0x5a, 0xf5, 0x1c, 0x80, 0x99, 0xbe, 0x4e, 0x41, 0xf0, 0xe8, 0xa6, 0x20, 0xab, 0x87,
0xc8, 0x1e, 0xa0, 0x59, 0x7b, 0x0c, 0xc3, 0x3c, 0x61, 0xcc, 0x40, 0x9e, 0x06, 0x52, 0x1b, 0x32,
0x8c, 0x12, 0x93, 0xbf, 0xef, 0x3b, 0x25, 0x0d, 0xc2, 0x88, 0xd1, 0xe0, 0x07, 0x2d, 0x70, 0xc6,
0x29, 0x6a, 0x4d, 0x47, 0x26, 0xa3, 0xe4, 0x8b, 0xf6, 0x97, 0x2c, 0x5d, 0x3d, 0xd7, 0x96, 0x28,
0x02, 0x08, 0x30, 0xa7, 0x22, 0xc9, 0x65, 0xf8, 0xb7, 0xb4, 0x8a, 0xca, 0xb9, 0xf2, 0xd0, 0x17,
0xff, 0x46, 0xfb, 0x9a, 0xba, 0x8f, 0xb6, 0x69, 0x68, 0x8e, 0x21, 0x6f, 0xc4, 0xcb, 0xb3, 0xce,
0x51, 0xd4, 0x81, 0x00, 0x2e, 0x9c, 0x74, 0x63, 0x45, 0xd9, 0x16, 0x35, 0x5f, 0xed, 0x78, 0x9f,
0x01, 0x48, 0x04, 0xc1, 0x33, 0xd6, 0x4f, 0x94, 0xde, 0x31, 0x9d, 0x0a, 0xac, 0x18, 0x4b, 0xcd,
0x98, 0xb8, 0x37, 0xa2, 0x83, 0xec, 0x03, 0xd8, 0xda, 0xe5, 0x7a, 0x6b, 0x53, 0xd5, 0x15, 0xa4,
0x43, 0xe9, 0x90, 0x67, 0x58, 0xc0, 0xa5, 0xfa, 0x2a, 0xb1, 0x75, 0x50, 0x39, 0x5c, 0xe6, 0xdc,
0x89, 0xfc, 0xcf, 0xfe, 0xf9, 0x57, 0x54, 0x64, 0xa8, 0xee, 0x23, 0x0b, 0xf1, 0xea, 0xfd, 0xdb,
0xbd, 0x09, 0xb5, 0x5b, 0x05, 0x86, 0x13, 0xf3, 0x24, 0xc5, 0x3f, 0x44, 0x72, 0x7c, 0x7e, 0x36
};
for (int i = 0; i < len; i++) {
arr[i] = lut[arr[i]];
}
}
//see ASK/MAN Demod for what args are accepted
int demodGallagher(bool verbose) {
@ -81,7 +107,7 @@ int demodGallagher(bool verbose) {
setDemodBuff(DemodBuffer, 96, ans);
setClockGrid(g_DemodClock, g_DemodStartIdx + (ans * g_DemodClock));
//got a good demod
// got a good demod
uint32_t raw1 = bytebits_to_byte(DemodBuffer, 32);
uint32_t raw2 = bytebits_to_byte(DemodBuffer + 32, 32);
uint32_t raw3 = bytebits_to_byte(DemodBuffer + 64, 32);
@ -89,14 +115,12 @@ int demodGallagher(bool verbose) {
// bytes
uint8_t arr[8] = {0};
for (int i = 0, pos = 0; i < ARRAYLEN(arr); i++) {
pos = (i * 8) + i;
pos = 16 + 9*i;
arr[i] = bytebits_to_byte(DemodBuffer + pos, 8);
PrintAndLogEx(NORMAL, "%d -" NOLF, pos);
}
PrintAndLogEx(NORMAL, "");
// crc
uint8_t crc = bytebits_to_byte(DemodBuffer + 72, 8);
uint8_t crc = bytebits_to_byte(DemodBuffer + 16 + 9*8, 8);
uint8_t calc_crc = CRC8Cardx(arr, ARRAYLEN(arr));
PrintAndLogEx(INFO, " Before: %s", sprint_hex(arr, 8));
@ -104,19 +128,19 @@ int demodGallagher(bool verbose) {
PrintAndLogEx(INFO, " After : %s", sprint_hex(arr, 8));
// 4bit region code
uint8_t rc = (arr[3] & 0x0E) >> 1;
uint8_t rc = (arr[3] & 0x1E) >> 1;
// 16bit FC
uint16_t fc = (arr[5] & 0x0F) << 12 | arr[1] << 4 | ((arr[7] >> 4) & 0x0F);
// 24bit CN
uint32_t cn = arr[0] << 16 | (arr[4] & 0x1F) << 11 | arr[2] << 3 | (arr[3] & 0xE0) >> 4;
uint32_t cn = arr[0] << 16 | (arr[4] & 0x1F) << 11 | arr[2] << 3 | (arr[3] & 0xE0) >> 5;
// 4bit issue level
uint8_t il = arr[7] & 0x0F;
PrintAndLogEx(SUCCESS, "GALLAGHER - Region: " _GREEN_("%u") " FC: " _GREEN_("%u") " CN: " _GREEN_("%u") " Issue Level: " _GREEN_("%u"), rc, fc, cn, il);
PrintAndLogEx(SUCCESS, " Printed: " _GREEN_("%C%u"), rc + 0x40, fc);
PrintAndLogEx(SUCCESS, " Displayed: " _GREEN_("%C%u"), rc + 'A', fc);
PrintAndLogEx(SUCCESS, " Raw: %08X%08X%08X", raw1, raw2, raw3);
PrintAndLogEx(SUCCESS, " CRC: %02X - %02X (%s)", crc, calc_crc, (crc == calc_crc) ? "ok" : "fail");
return PM3_SUCCESS;

4
common/crc.c
View file

@ -126,10 +126,10 @@ uint32_t CRC8Legic(uint8_t *buff, size_t size) {
crc_update2(&crc, buff[i], 8);
return reflect8(crc_finish(&crc));
}
// width=8 poly=0x107, init=0x2C refin=true refout=true xorout=0x0000 check=0 name="CRC-8/CARDX"
// width=8 poly=0x7, init=0x2C refin=false refout=false xorout=0x0000 check=0 name="CRC-8/CARDX"
uint32_t CRC8Cardx(uint8_t *buff, size_t size) {
crc_t crc;
crc_init_ref(&crc, 8, 0x107, 0x2C, 0, true, true);
crc_init_ref(&crc, 8, 0x7, 0x2C, 0, false, false);
for (size_t i = 0; i < size; ++i)
crc_update2(&crc, buff[i], 8);
return crc_finish(&crc);