From 3b920280db306fd05322be0e70156e51dd2191f1 Mon Sep 17 00:00:00 2001 From: iceman1001 Date: Sun, 14 Feb 2016 11:56:54 +0100 Subject: [PATCH] ADD: Calc legic Crc8 method on given input hexstring. --- client/cmdhflegic.c | 124 +++++++++++++++++++++++++++----------------- client/cmdhflegic.h | 3 ++ 2 files changed, 80 insertions(+), 47 deletions(-) diff --git a/client/cmdhflegic.c b/client/cmdhflegic.c index 2d198820..f40ff963 100644 --- a/client/cmdhflegic.c +++ b/client/cmdhflegic.c @@ -17,24 +17,35 @@ #include "cmdhflegic.h" #include "cmdmain.h" #include "util.h" +#include "crc.h" static int CmdHelp(const char *Cmd); +int usage_legic_calccrc8(void){ + PrintAndLog("Calculates the legic crc8 on the input hexbytes."); + PrintAndLog("There must be an even number of hexsymbols as input."); + PrintAndLog("Usage: hf legic crc8 "); + PrintAndLog("Options :"); + PrintAndLog(" : hex bytes in a string"); + PrintAndLog(""); + PrintAndLog("Sample : hf legic crc8 deadbeef1122"); + 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 */ -int CmdLegicDecode(const char *Cmd) -{ - int i, j, k, n; +int CmdLegicDecode(const char *Cmd) { + int i, k, n; int segment_len = 0; int segment_flag = 0; int stamp_len = 0; int crc = 0; int wrp = 0; int wrc = 0; - uint8_t data_buf[3076]; // receiver buffer - char out_string[3076]; // just use big buffer - bad practice + uint8_t data_buf[1200]; // receiver buffer + //char out_string[3076]; // just use big buffer - bad practice char token_type[4]; // copy data from proxmark into buffer @@ -42,18 +53,19 @@ int CmdLegicDecode(const char *Cmd) WaitForResponse(CMD_ACK,NULL); // Output CDF System area (9 bytes) plus remaining header area (12 bytes) - + crc = data_buf[4]; + uint32_t calc_crc = CRC8Legic(data_buf, 4); + PrintAndLog("\nCDF: System Area"); - PrintAndLog("MCD: %02x, MSN: %02x %02x %02x, MCC: %02x", + PrintAndLog("MCD: %02x, MSN: %02x %02x %02x, MCC: %02x %s", data_buf[0], data_buf[1], data_buf[2], data_buf[3], - data_buf[4] + data_buf[4], + (calc_crc == crc) ? "OK":"Failed" ); - - crc = data_buf[4]; switch (data_buf[5]&0x7f) { case 0x00 ... 0x2f: @@ -116,46 +128,46 @@ int CmdLegicDecode(const char *Cmd) (data_buf[i+4]^crc) ); - i+=5; + i += 5; if ( wrc>0 ) { PrintAndLog("WRC protected area:"); - for ( k=0, j=0; k < wrc && j<(sizeof(out_string)-3); 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); + + for ( k=i; k < wrc; k++) + data_buf[k] ^= crc; + + for ( k=i; k < wrc; k += 8) + PrintAndLog("%s", sprint_hex( data_buf+k, 8) ); + + i += wrc; } if ( wrp>wrc ) { PrintAndLog("Remaining write protected area:"); - for (k=0, j=0; k < (wrp-wrc) && j<(sizeof(out_string)-3); 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); + if ( data_buf[k] > 0) { + for (k=i; k < (wrp-wrc); k++) + data_buf[k] ^= crc; } + + for (k=i; k < (wrp-wrc); k++) + PrintAndLog("%s", sprint_hex( data_buf+k, 16) ); + + i += (wrp-wrc); + + if( (wrp-wrc) == 8 ) + PrintAndLog("Card ID: %2X%02X%02X", data_buf[i-4]^crc, data_buf[i-3]^crc, data_buf[i-2]^crc); } PrintAndLog("Remaining segment payload:"); - for ( k=0, j=0; k < (segment_len - wrp - 5) && j<(sizeof(out_string)-3); 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 ( data_buf[k] > 0 ) { + for ( k=i; k < (segment_len - wrp - 5); k++) + data_buf[k] ^= crc; + } + + for ( k=i; k < (segment_len - wrp - 5); k++) + PrintAndLog("%s", sprint_hex( data_buf+k, 16) ); // end with last segment if (segment_flag & 0x8) return 0; @@ -282,7 +294,7 @@ int CmdLegicSave(const char *Cmd) { } int CmdLegicRfSim(const char *Cmd) { - UsbCommand c= {CMD_SIMULATE_TAG_LEGIC_RF, {6,3,0}}; + UsbCommand c = {CMD_SIMULATE_TAG_LEGIC_RF, {6,3,0}}; sscanf(Cmd, " %"lli" %"lli" %"lli, &c.arg[0], &c.arg[1], &c.arg[2]); clearCommandBuffer(); SendCommand(&c); @@ -325,15 +337,33 @@ int CmdLegicRfFill(const char *Cmd) { return 0; } + +int CmdLegicCalcCrc8(const char *Cmd){ + + int len = strlen(Cmd); + if (len & 1 ) return usage_legic_calccrc8(); + + uint8_t *data = malloc(len); + if ( data == NULL ) return 1; + + param_gethex(Cmd, 0, data, len ); + + uint32_t checksum = CRC8Legic(data, len/2); + PrintAndLog("Bytes: %s || CRC8: %X", sprint_hex(data, len/2), checksum ); + free(data); + return 0; +} + static command_t CommandTable[] = { - {"help", CmdHelp, 1, "This help"}, - {"decode", CmdLegicDecode, 0, "Display deobfuscated and decoded LEGIC RF tag data (use after hf legic reader)"}, - {"reader", CmdLegicRFRead, 0, "[offset [length]] -- read bytes from a LEGIC card"}, - {"save", CmdLegicSave, 0, " [] -- Store samples"}, - {"load", CmdLegicLoad, 0, " -- Restore samples"}, - {"sim", CmdLegicRfSim, 0, "[phase drift [frame drift [req/resp drift]]] Start tag simulator (use after load or read)"}, - {"write", CmdLegicRfWrite,0, " -- Write sample buffer (user after load or read)"}, - {"fill", CmdLegicRfFill, 0, " -- Fill/Write tag with constant value"}, + {"help", CmdHelp, 1, "This help"}, + {"decode", CmdLegicDecode, 0, "Display deobfuscated and decoded LEGIC RF tag data (use after hf legic reader)"}, + {"read", CmdLegicRFRead, 0, "[offset][length] -- read bytes from a LEGIC card"}, + {"save", CmdLegicSave, 0, " [] -- Store samples"}, + {"load", CmdLegicLoad, 0, " -- Restore samples"}, + {"sim", CmdLegicRfSim, 0, "[phase drift [frame drift [req/resp drift]]] Start tag simulator (use after load or read)"}, + {"write", CmdLegicRfWrite,0, " -- Write sample buffer (user after load or read)"}, + {"fill", CmdLegicRfFill, 0, " -- Fill/Write tag with constant value"}, + {"crc8", CmdLegicCalcCrc8, 1, "Calculate Legic CRC8 over given hexbytes"}, {NULL, NULL, 0, NULL} }; diff --git a/client/cmdhflegic.h b/client/cmdhflegic.h index ab8bc6fd..31082155 100644 --- a/client/cmdhflegic.h +++ b/client/cmdhflegic.h @@ -21,4 +21,7 @@ int CmdLegicRfSim(const char *Cmd); int CmdLegicRfWrite(const char *Cmd); int CmdLegicRfFill(const char *Cmd); +int CmdLegicCalcCrc8(const char *Cmd); + +int usage_legic_calccrc8(void); #endif -- 2.39.5