fix false positive psk demod with fsk wave

[proxmark3-svn] / client / cmdlfem4x.c

diff --git a/client/cmdlfem4x.c b/client/cmdlfem4x.c
index 7664978639fd425de6e752f327518d1f491962fa..d1245306ef00d0256de5ec23ea1163fa5fb5c9c7 100644 (file)
--- a/client/cmdlfem4x.c
+++ b/client/cmdlfem4x.c
@@ -530,14 +530,16 @@ bool downloadSamplesEM() {
 }
 
 bool EM4x05testDemodReadData(uint32_t *word, bool readCmd) {
-       // em4x05/em4x69 preamble is 00001010
+       // em4x05/em4x69 command response preamble is 00001010
        // skip first two 0 bits as they might have been missed in the demod
        uint8_t preamble[] = {0,0,1,0,1,0};
        size_t startIdx = 0;
-       // set size to 20 to only test first 14 positions for the preamble
-       size_t size = (20 > DemodBufferLen) ? DemodBufferLen : 20;
 
-       //test preamble
+       // set size to 20 to only test first 14 positions for the preamble or less if not a read command
+       size_t size = (readCmd) ? 20 : 11;
+       // sanity check
+       size = (size > DemodBufferLen) ? DemodBufferLen : size;
+       // test preamble
        if ( !onePreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx) ) {
                if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
                return false;
@@ -548,7 +550,7 @@ bool EM4x05testDemodReadData(uint32_t *word, bool readCmd) {
                        if (g_debugMode) PrintAndLog("DEBUG: Error - End Parity check failed");
                        return false;
                }
-               //test for even parity bits.
+               // test for even parity bits.
                if ( removeParity(DemodBuffer, startIdx + sizeof(preamble),9,0,44) == 0 ) {             
                        if (g_debugMode) PrintAndLog("DEBUG: Error - Parity not detected");
                        return false;
@@ -808,6 +810,8 @@ int CmdEM4x05WriteWord(const char *Cmd) {
        int result = demodEM4x05resp(&dummy,false);
        if (result == 1) {
                PrintAndLog("Write Verified");
+       } else {
+               PrintAndLog("Write could not be verified");
        }
        return result;
 }
@@ -893,6 +897,12 @@ void printEM4x05info(uint8_t chipType, uint8_t cap, uint16_t custCode, uint32_t
        }
 }
 
+void printEM4x05ProtectionBits(uint32_t wordData) {
+       for (uint8_t i = 0; i < 14; i++) {
+               PrintAndLog("      Word:  %02u | %s", i, (((1 << i) & wordData ) || i < 2) ? "Is Locked" : "Is Not Locked");
+       }
+}
+
 //quick test for EM4x05/EM4x69 tag
 bool EM4x05Block0Test(uint32_t *wordData) {
        if (EM4x05ReadWord_ext(0,0,false,wordData) == 1) {
@@ -940,6 +950,26 @@ int CmdEM4x05info(const char *Cmd) {
                return 0;
        }
        printEM4x05config(wordData);
+
+       // read word 14 and 15 to see which is being used for the protection bits
+       wordData = 0;
+       if ( EM4x05ReadWord_ext(14, pwd, usePwd, &wordData) != 1 ) {
+               //failed
+               return 0;
+       }
+       // if status bit says this is not the used protection word
+       if (!(wordData & 0x8000)) {
+               if ( EM4x05ReadWord_ext(15, pwd, usePwd, &wordData) != 1 ) {
+                       //failed
+                       return 0;
+               }
+       }
+       if (!(wordData & 0x8000)) {
+               //something went wrong
+               return 0;
+       }
+       printEM4x05ProtectionBits(wordData);
+
        return 1;
 }