X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/dc8ba239fbc1b8f50f572e84adfcfdf52bd0d0da..dfb387bf0f73129f4bcb27eb4c840d9a35f390d6:/armsrc/iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 2fd568b9..0431876e 100644
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -551,12 +551,8 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 	
 	LEDsoff();
 
-	// We won't start recording the frames that we acquire until we trigger;
-	// a good trigger condition to get started is probably when we see a
-	// response from the tag.
-	// triggered == FALSE -- to wait first for card
-	bool triggered = !(param & 0x03); 
-	
+	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
+
 	// Allocate memory from BigBuf for some buffers
 	// free all previous allocations first
 	BigBuf_free();
@@ -583,8 +579,6 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 	bool TagIsActive = FALSE;
 	bool ReaderIsActive = FALSE;
 	
-	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
-
 	// Set up the demodulator for tag -> reader responses.
 	DemodInit(receivedResponse, receivedResponsePar);
 	
@@ -594,6 +588,12 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 	// Setup and start DMA.
 	FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
 	
+	// We won't start recording the frames that we acquire until we trigger;
+	// a good trigger condition to get started is probably when we see a
+	// response from the tag.
+	// triggered == FALSE -- to wait first for card
+	bool triggered = !(param & 0x03); 
+	
 	// And now we loop, receiving samples.
 	for(uint32_t rsamples = 0; TRUE; ) {
 
@@ -1026,6 +1026,9 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 		.modulation_n = 0
 	};
   
+	// We need to listen to the high-frequency, peak-detected path.
+	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
+
 	BigBuf_free_keep_EM();
 
 	// allocate buffers:
@@ -1054,16 +1057,12 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 	int happened2 = 0;
 	int cmdsRecvd = 0;
 
-	// We need to listen to the high-frequency, peak-detected path.
-	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-
 	cmdsRecvd = 0;
 	tag_response_info_t* p_response;
 
 	LED_A_ON();
 	for(;;) {
 		// Clean receive command buffer
-		
 		if(!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) {
 			DbpString("Button press");
 			break;
@@ -1994,6 +1993,10 @@ void ReaderMifare(bool first_try)
 	uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE];
 	uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE];
 
+	if (first_try) { 
+		iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
+	}
+	
 	// free eventually allocated BigBuf memory. We want all for tracing.
 	BigBuf_free();
 	
@@ -2013,6 +2016,7 @@ void ReaderMifare(bool first_try)
 	byte_t par_list[8] = {0x00};
 	byte_t ks_list[8] = {0x00};
 
+	#define PRNG_SEQUENCE_LENGTH  (1 << 16);
 	static uint32_t sync_time;
 	static uint32_t sync_cycles;
 	int catch_up_cycles = 0;
@@ -2022,9 +2026,8 @@ void ReaderMifare(bool first_try)
 
 	if (first_try) { 
 		mf_nr_ar3 = 0;
-		iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
 		sync_time = GetCountSspClk() & 0xfffffff8;
-		sync_cycles = 65536;									// theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
+		sync_cycles = PRNG_SEQUENCE_LENGTH;							// theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the tag nonces).
 		nt_attacked = 0;
 		nt = 0;
 		par[0] = 0;
@@ -2041,8 +2044,12 @@ void ReaderMifare(bool first_try)
 	LED_C_OFF();
 	
 
-	#define DARKSIDE_MAX_TRIES	32		// number of tries to sync on PRNG cycle. Then give up.
-	uint16_t unsuccessfull_tries = 0;
+	#define MAX_UNEXPECTED_RANDOM	4		// maximum number of unexpected (i.e. real) random numbers when trying to sync. Then give up.
+	#define MAX_SYNC_TRIES			16
+	uint16_t unexpected_random = 0;
+	uint16_t sync_tries = 0;
+	int16_t debug_info_nr = -1;
+	uint32_t debug_info[MAX_SYNC_TRIES];
 	
 	for(uint16_t i = 0; TRUE; i++) {
 		
@@ -2060,16 +2067,20 @@ void ReaderMifare(bool first_try)
 			continue;
 		}
 
-		sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
-		catch_up_cycles = 0;
+		if (debug_info_nr == -1) {
+			sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
+			catch_up_cycles = 0;
 
-		// if we missed the sync time already, advance to the next nonce repeat
-		while(GetCountSspClk() > sync_time) {
-			sync_time = (sync_time & 0xfffffff8) + sync_cycles;
-		}
+			// if we missed the sync time already, advance to the next nonce repeat
+			while(GetCountSspClk() > sync_time) {
+				sync_time = (sync_time & 0xfffffff8) + sync_cycles;
+			}
 
-		// Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
-		ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+			// Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
+			ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+		} else {
+			ReaderTransmit(mf_auth, sizeof(mf_auth), NULL);
+		}			
 
 		// Receive the (4 Byte) "random" nonce
 		if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {
@@ -2087,19 +2098,32 @@ void ReaderMifare(bool first_try)
 			int nt_distance = dist_nt(previous_nt, nt);
 			if (nt_distance == 0) {
 				nt_attacked = nt;
-			}
-			else {
+			} else {
 				if (nt_distance == -99999) { // invalid nonce received
-					unsuccessfull_tries++;
-					if (!nt_attacked && unsuccessfull_tries > DARKSIDE_MAX_TRIES) {
+					unexpected_random++;
+					if (!nt_attacked && unexpected_random > MAX_UNEXPECTED_RANDOM) {
 						isOK = -3;		// Card has an unpredictable PRNG. Give up	
 						break;
 					} else {
 						continue;		// continue trying...
 					}
 				}
+				if (++sync_tries > MAX_SYNC_TRIES) {
+					if (sync_tries > 2 * MAX_SYNC_TRIES) {
+						isOK = -4; 			// Card's PRNG runs at an unexpected frequency or resets unexpectedly
+						break;
+					} else {				// continue for a while, just to collect some debug info
+						debug_info[++debug_info_nr] = nt_distance;
+						continue;
+					}
+				}
 				sync_cycles = (sync_cycles - nt_distance);
-				if (MF_DBGLEVEL >= 3) Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
+				if (sync_cycles <= 0) {
+					sync_cycles += PRNG_SEQUENCE_LENGTH;
+				}
+				if (MF_DBGLEVEL >= 3) {
+					Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
+				}
 				continue;
 			}
 		}
@@ -2170,6 +2194,14 @@ void ReaderMifare(bool first_try)
 
 
 	mf_nr_ar[3] &= 0x1F;
+
+	if (isOK == -4) {
+		if (MF_DBGLEVEL >= 3) {
+			for(uint16_t i = 0; i < MAX_SYNC_TRIES; i++) {
+				Dbprintf("collected debug info[%d] = %d\n", i, debug_info[i]);
+			}
+		}
+	}
 	
 	byte_t buf[28];
 	memcpy(buf + 0,  uid, 4);
@@ -2239,13 +2271,6 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 	uint32_t ar_nr_responses[] = {0,0,0,0,0,0,0,0};
 	uint8_t ar_nr_collected = 0;
 
-	// free eventually allocated BigBuf memory but keep Emulator Memory
-	BigBuf_free_keep_EM();
-
-	// clear trace
-	clear_trace();
-	set_tracing(TRUE);
-
 	// Authenticate response - nonce
 	uint32_t nonce = bytes_to_num(rAUTH_NT, 4);
 	
@@ -2287,10 +2312,6 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 		rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
 	}
 
-	// We need to listen to the high-frequency, peak-detected path.
-	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-
-
 	if (MF_DBGLEVEL >= 1)	{
 		if (!_7BUID) {
 			Dbprintf("4B UID: %02x%02x%02x%02x", 
@@ -2302,6 +2323,17 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 		}
 	}
 
+	// We need to listen to the high-frequency, peak-detected path.
+	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
+
+	// free eventually allocated BigBuf memory but keep Emulator Memory
+	BigBuf_free_keep_EM();
+
+	// clear trace
+	clear_trace();
+	set_tracing(TRUE);
+
+
 	bool finished = FALSE;
 	while (!BUTTON_PRESS() && !finished) {
 		WDT_HIT();
@@ -2720,10 +2752,8 @@ void RAMFUNC SniffMifare(uint8_t param) {
 	uint8_t receivedResponse[MAX_MIFARE_FRAME_SIZE];
 	uint8_t receivedResponsePar[MAX_MIFARE_PARITY_SIZE];
 
-	// As we receive stuff, we copy it from receivedCmd or receivedResponse
-	// into trace, along with its length and other annotations.
-	//uint8_t *trace = (uint8_t *)BigBuf;
-	
+	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
+
 	// free eventually allocated BigBuf memory
 	BigBuf_free();
 	// allocate the DMA buffer, used to stream samples from the FPGA
@@ -2735,8 +2765,6 @@ void RAMFUNC SniffMifare(uint8_t param) {
 	bool ReaderIsActive = FALSE;
 	bool TagIsActive = FALSE;
 
-	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
-
 	// Set up the demodulator for tag -> reader responses.
 	DemodInit(receivedResponse, receivedResponsePar);