+
+/*
+ * Output BigBuf and deobfuscate LEGIC RF tag data.
+ * This is based on information given in the talk held
+ * by Henryk Ploetz and Karsten Nohl at 26c3
+ * FIXME: will crash if sample buffer does not contain valid legic data
+ */
+int CmdLegicDecode(const char *Cmd)
+{
+ int h, i, j, k, n;
+ int segment_len = 0;
+ int segment_flag = 0;
+ int stamp_len = 0;
+ int crc = 0;
+ int wrp = 0;
+ int wrc = 0;
+ int data_buf[1032]; // receiver buffer
+ char out_string[3076]; // just use big buffer - bad practice
+ char token_type[4];
+ int delivered = 0;
+
+ h = 0;
+
+ // copy data from proxmark into buffer
+ for (i = 0; i < 256; i += 12, h += 48) {
+ UsbCommand c = {CMD_DOWNLOAD_RAW_ADC_SAMPLES_125K, {i, 0, 0}};
+ SendCommand(&c);
+ WaitForResponse(CMD_DOWNLOADED_RAW_ADC_SAMPLES_125K);
+
+ for (j = 0; j < 48; j += 8) {
+ for (k = 0; k < 8; k++) {
+ data_buf[h+j+k] = sample_buf[j+k];
+ }
+ delivered += 8;
+ if (delivered >= 1024)
+ break;
+ }
+ }
+
+ // Output CDF System area (9 bytes) plus remaining header area (12 bytes)
+
+ PrintAndLog("\nCDF: System Area");
+
+ PrintAndLog("MCD: %02x, MSN: %02x %02x %02x, MCC: %02x",
+ data_buf[0],
+ data_buf[1],
+ data_buf[2],
+ data_buf[3],
+ data_buf[4]
+ );
+
+ crc = data_buf[4];
+
+ switch (data_buf[5]&0x7f) {
+ case 0x00 ... 0x2f:
+ strncpy(token_type, "IAM",sizeof(token_type));
+ break;
+ case 0x30 ... 0x6f:
+ strcpy(token_type, "SAM");
+ break;
+ case 0x70 ... 0x7f:
+ strcpy(token_type, "GAM");
+ break;
+ default:
+ strcpy(token_type, "???");
+ break;
+ }
+
+ stamp_len = 0xfc - data_buf[6];
+
+ PrintAndLog("DCF: %02x %02x, Token_Type=%s (OLE=%01u), Stamp_len=%02u",
+ data_buf[5],
+ data_buf[6],
+ token_type,
+ (data_buf[5]&0x80)>>7,
+ stamp_len
+ );
+
+ PrintAndLog("WRP=%02u, WRC=%01u, RD=%01u, raw=%02x, SSC=%02x",
+ data_buf[7]&0x0f,
+ (data_buf[7]&0x70)>>4,
+ (data_buf[7]&0x80)>>7,
+ data_buf[7],
+ data_buf[8]
+ );
+
+ PrintAndLog("Remaining Header Area");
+
+ PrintAndLog("%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
+ data_buf[9],
+ data_buf[10],
+ data_buf[11],
+ data_buf[12],
+ data_buf[13],
+ data_buf[14],
+ data_buf[15],
+ data_buf[16],
+ data_buf[17],
+ data_buf[18],
+ data_buf[19],
+ data_buf[20],
+ data_buf[21]
+ );
+
+ PrintAndLog("\nADF: User Area");
+
+ i = 22;
+ for (n=0; n<64; n++) {
+ segment_len = ((data_buf[i+1]^crc)&0x0f) * 256 + (data_buf[i]^crc);
+ segment_flag = ((data_buf[i+1]^crc)&0xf0)>>4;
+
+ wrp = (data_buf[i+2]^crc);
+ wrc = ((data_buf[i+3]^crc)&0x70)>>4;
+
+ PrintAndLog("Segment %02u: raw header=%02x %02x %02x %02x, flag=%01x (valid=%01u, last=%01u), len=%04u, WRP=%02u, WRC=%02u, RD=%01u, CRC=%02x",
+ n,
+ data_buf[i]^crc,
+ data_buf[i+1]^crc,
+ data_buf[i+2]^crc,
+ data_buf[i+3]^crc,
+ segment_flag,
+ (segment_flag&0x4)>>2,
+ (segment_flag&0x8)>>3,
+ segment_len,
+ wrp,
+ wrc,
+ ((data_buf[i+3]^crc)&0x80)>>7,
+ (data_buf[i+4]^crc)
+ );
+
+ i+=5;
+
+ if (wrc>0) {
+ PrintAndLog("WRC protected area:");
+ for (k=0, j=0; k < wrc; k++, i++, j += 3) {
+ sprintf(&out_string[j], "%02x", (data_buf[i]^crc));
+ out_string[j+2] = ' ';
+ };
+
+ out_string[j] = '\0';
+
+ PrintAndLog("%s", out_string);
+ }
+
+ if (wrp>wrc) {
+ PrintAndLog("Remaining write protected area:");
+
+ for (k=0, j=0; k < (wrp-wrc); k++, i++, j += 3) {
+ sprintf(&out_string[j], "%02x", (data_buf[i]^crc));
+ out_string[j+2] = ' ';
+ };
+
+ out_string[j] = '\0';
+
+ PrintAndLog("%s", out_string);
+ if((wrp-wrc) == 8) {
+ sprintf(out_string,"Card ID: %2X%02X%02X",data_buf[i-4]^crc,data_buf[i-3]^crc,data_buf[i-2]^crc);
+ PrintAndLog("%s", out_string);
+ }
+ }
+
+ PrintAndLog("Remaining segment payload:");
+ for (k=0, j=0; k < (segment_len - wrp - 5); k++, i++, j += 3) {
+ sprintf(&out_string[j], "%02x", (data_buf[i]^crc));
+ out_string[j+2] = ' ';
+ };
+
+ out_string[j] = '\0';
+
+ PrintAndLog("%s", out_string);
+
+ // end with last segment
+ if (segment_flag & 0x8)
+ return 0;
+ };
+ return 0;
+}