X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/6f1a597855d5ba70e0d37613ffe144e63690a058..2d99d9912c430b09c8178c9154a44a99e7ee6561:/client/cmdlfem4x.c

diff --git a/client/cmdlfem4x.c b/client/cmdlfem4x.c
index 820b24e9..2d1600f6 100644
--- a/client/cmdlfem4x.c
+++ b/client/cmdlfem4x.c
@@ -514,17 +514,17 @@ int usage_lf_em_read(void) {
 }
 
 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex
-uint8_t EMpreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t size, size_t *startIdx)
-{
+uint8_t EMpreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t size, size_t *startIdx) {
 	// Sanity check.  If preamble length is bigger than bitstream length.
 	if ( size <= pLen ) return 0;
 	// em only sends preamble once, so look for it once in the first x bits
 	uint8_t foundCnt = 0;
-	for (int idx = 0; idx < size - pLen; idx++){
+	for (size_t idx = 0; idx < size - pLen; idx++){
 		if (memcmp(BitStream+idx, preamble, pLen) == 0){
 			//first index found
 			foundCnt++;
 			if (foundCnt == 1) {
+				if (g_debugMode) PrintAndLog("DEBUG: preamble found at %u", idx);
 				*startIdx = idx;
 				return 1;
 			}
@@ -533,12 +533,16 @@ uint8_t EMpreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, siz
 	return 0;
 }
 
+// FSK, PSK, ASK/MANCHESTER, ASK/BIPHASE, ASK/DIPHASE 
+// should cover 90% of known used configs
+// the rest will need to be manually demoded for now...
 int demodEM4x05resp(uint8_t bitsNeeded) {
 	int ans = 0;
 	bool demodFound = false;
 	DemodBufferLen = 0x00;
 	// skip first two 0 bits as they might have been missed in the demod 
 	uint8_t preamble[6] = {0,0,1,0,1,0};
+	size_t startIdx = 0; 
 
 	// test for FSK wave (easiest to 99% ID)
 	if (GetFskClock("", FALSE, FALSE)) {
@@ -546,18 +550,16 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
 		ans = FSKrawDemod("0 0", false);
 		if (!ans) {
 			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: FSK Demod failed");
-			//return -1;
 		} else {
 			// set size to 10 to only test first 4 positions for the preamble
 			size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
-			size_t startIdx = 0; 
+			startIdx = 0; 
 
 			if (g_debugMode) PrintAndLog("ANS: %d | %u | %u", ans, startIdx, size);
 
-			uint8_t errChk = !EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
+			uint8_t errChk = EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
 			if ( errChk == 0) {
 				if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
-				//return -1;
 			} else {
 				//can't test size because the preamble doesn't repeat :(
 				//meaning chances of false positives are high.
@@ -565,10 +567,38 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
 			}
 		}
 	}
+	// PSK clocks should be easy to detect ( but difficult to demod a non-repeating pattern... )
+	if (!demodFound) {
+		ans = GetPskClock("", FALSE, FALSE);
+		if (ans>0) {
+			PrintAndLog("PSK response possibly found, run `data rawd p1` to attempt to demod");
+		}
+	}
+
+	// more common than biphase
+	if (!demodFound) {
+		DemodBufferLen = 0x00;
+		bool stcheck = false;
+		// try manchester - NOTE: ST only applies to T55x7 tags.
+		ans = ASKDemod_ext("0,0,1", false, false, 1, &stcheck);
+		if (!ans) {
+			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/Manchester Demod failed");
+		} else {
+			// set size to 10 to only test first 4 positions for the preamble
+			size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
+			startIdx = 0; 
 
-	ans = GetPskClock("", FALSE, FALSE);
-	if (ans>0) {
-		PrintAndLog("PSK response possibly found, run `data rawd p1` to attempt to demod");
+			if (g_debugMode) PrintAndLog("ANS: %d | %u | %u", ans, startIdx, size);
+
+			uint8_t errChk = EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
+			if ( errChk == 0) {
+				if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
+			} else {
+				//can't test size because the preamble doesn't repeat :(
+				//meaning chances of false positives are high.
+				demodFound = true;
+			}
+		}
 	}
 
 	if (!demodFound) {
@@ -577,18 +607,16 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
 		ans = ASKbiphaseDemod("0 0 1", FALSE);
 		if (!ans) { 
 			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/biphase Demod failed");
-			//return -1;
 		} else {
 			// set size to 10 to only test first 4 positions for the preamble
 			size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
-			size_t startIdx = 0; 
+			startIdx = 0; 
 
 			if (g_debugMode) PrintAndLog("ANS: %d | %u | %u", ans, startIdx, size);
 
-			uint8_t errChk = !EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
+			uint8_t errChk = EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
 			if ( errChk == 0) {
 				if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
-				//return -1;
 			} else {
 				//can't test size because the preamble doesn't repeat :(
 				//meaning chances of false positives are high.
@@ -599,22 +627,20 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
 
 	if (!demodFound) {
 		DemodBufferLen = 0x00;
-		// try manchester - NOTE: ST only applies to T55x7 tags.
-		ans = ASKDemod_ext("0,0,1", false, false, 1, false);
-		if (!ans) {
-			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/Manchester Demod failed");
-			//return -1;
+		//try diphase (differential biphase or inverted)
+		ans = ASKbiphaseDemod("0 1 1", FALSE);
+		if (!ans) { 
+			if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/biphase Demod failed");
 		} else {
 			// set size to 10 to only test first 4 positions for the preamble
 			size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
-			size_t startIdx = 0; 
+			startIdx = 0; 
 
 			if (g_debugMode) PrintAndLog("ANS: %d | %u | %u", ans, startIdx, size);
 
-			uint8_t errChk = !EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
+			uint8_t errChk = EMpreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx);
 			if ( errChk == 0) {
 				if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
-				//return -1;
 			} else {
 				//can't test size because the preamble doesn't repeat :(
 				//meaning chances of false positives are high.
@@ -624,8 +650,10 @@ int demodEM4x05resp(uint8_t bitsNeeded) {
 	}
 
 	if (demodFound && bitsNeeded < DemodBufferLen) {
-		setDemodBuf(DemodBuffer + ans + sizeof(preamble), bitsNeeded, 0);
-		CmdPrintDemodBuff("x");
+		if (bitsNeeded > 0) {
+			setDemodBuf(DemodBuffer + startIdx + sizeof(preamble), bitsNeeded, 0);
+			CmdPrintDemodBuff("x");			
+		}
 		return 1;
 	}
 	return -1;
@@ -673,10 +701,9 @@ int CmdReadWord(const char *Cmd) {
 		return -1;
 	}
 
-	//need 32 bits for read word
-	demodEM4x05resp(32);
-
-	return 1;
+	//attempt demod:
+	//need 32 bits from a read word
+	return demodEM4x05resp(44);
 }
 
 int usage_lf_em_write(void) {
@@ -693,6 +720,7 @@ int usage_lf_em_write(void) {
 	PrintAndLog("      lf em writeword 1 deadc0de 11223344");
 	return 0;
 }
+
 int CmdWriteWord(const char *Cmd) {
 	uint8_t ctmp = param_getchar(Cmd, 0);
 	if ( strlen(Cmd) == 0 || ctmp == 'H' || ctmp == 'h' ) return usage_lf_em_write();
@@ -738,7 +766,14 @@ int CmdWriteWord(const char *Cmd) {
 	}
 	setGraphBuf(got, sizeof(got));
 	//todo: check response for 00001010 then write data for write confirmation!
-	return 0;
+	
+	//attempt demod:
+	//need 0 bits demoded (after preamble) to verify write cmd
+	int result = demodEM4x05resp(0);
+	if (result == 1) {
+		PrintAndLog("Write Verified");
+	}
+	return result;
 }
 
 /*