From 669c1b80c563bb9cb7eda52c6d01e720453d00b0 Mon Sep 17 00:00:00 2001 From: "adam@algroup.co.uk" Date: Fri, 5 Feb 2010 13:56:33 +0000 Subject: [PATCH 1/1] add LEGIC decoder (submitted by Sourcerer, untested by me) --- client/cmdhflegic.c | 183 ++++++++++++++++++++++++++++++++++++++++++++ client/cmdhflegic.h | 1 + 2 files changed, 184 insertions(+) diff --git a/client/cmdhflegic.c b/client/cmdhflegic.c index e2229a73..cc4e0ff2 100644 --- a/client/cmdhflegic.c +++ b/client/cmdhflegic.c @@ -3,6 +3,11 @@ #include "proxusb.h" #include "cmdparser.h" #include "cmdhflegic.h" +#include "cmdmain.h" +#include "data.h" +#include "ui.h" +#include +#include static int CmdHelp(const char *Cmd); @@ -21,6 +26,7 @@ static command_t CommandTable[] = { {"help", CmdHelp, 1, "This help"}, {"reader", CmdLegicRFRead, 0, "[offset [length]] -- read bytes from a LEGIC card"}, + {"decode", CmdLegicDecode, 0, "Display deobfuscated and decoded LEGIC RF tag data (use after hf legic reader)"}, {NULL, NULL, 0, NULL} }; @@ -35,3 +41,180 @@ int CmdHelp(const char *Cmd) CmdsHelp(CommandTable); return 0; } + +/* + * 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; +} diff --git a/client/cmdhflegic.h b/client/cmdhflegic.h index 1810322f..7da1be61 100644 --- a/client/cmdhflegic.h +++ b/client/cmdhflegic.h @@ -4,5 +4,6 @@ int CmdHFLegic(const char *Cmd); int CmdLegicRFRead(const char *Cmd); +int CmdLegicDecode(const char *Cmd); #endif -- 2.39.5