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em4x05 - psk detection improvement

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This commit is contained in:
iceman1001 2020-10-21 13:29:45 +02:00
parent ea6ac60726
commit 6c4b629547
1 changed files with 36 additions and 2 deletions
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38
client/src/cmdlfem4x05.c
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@ -171,16 +171,19 @@ static int doPreambleSearch(size_t *startIdx) {
// do not set it too long else an error preamble followed by 010 could be seen as success.
size_t size = (11 > DemodBufferLen) ? DemodBufferLen : 11;
*startIdx = 0;
// skip first two 0 bits as they might have been missed in the demod
uint8_t preamble[EM_PREAMBLE_LEN] = {0, 0, 0, 0, 1, 0, 1, 0};
uint8_t errpreamble[EM_PREAMBLE_LEN] = {0, 0, 0, 0, 0, 0, 0, 1};
if (!preambleSearchEx(DemodBuffer, preamble, EM_PREAMBLE_LEN, &size, startIdx, true)) {
uint8_t errpreamble[EM_PREAMBLE_LEN] = {0, 0, 0, 0, 0, 0, 0, 1};
if (!preambleSearchEx(DemodBuffer, errpreamble, EM_PREAMBLE_LEN, &size, startIdx, true)) {
PrintAndLogEx(DEBUG, "DEBUG: Error - EM4305 preamble not found :: %zu", *startIdx);
return PM3_ESOFT;
}
return PM3_EFAILED; // Error preamble found
}
return PM3_SUCCESS;
}
@ -211,6 +214,18 @@ static bool detectPSK(void) {
ans = PSKDemod(0, 0, 6, false);
if (ans != PM3_SUCCESS) {
PrintAndLogEx(DEBUG, "DEBUG: Error - EM: PSK1 Demod failed");
return false;
}
// In order to hit the INVERT, we need to demod here
if (DemodBufferLen < 11) {
PrintAndLogEx(INFO," demod buff len less than PREAMBLE lEN");
}
size_t size = (11 > DemodBufferLen) ? DemodBufferLen : 11;
size_t startIdx = 0;
uint8_t preamble[EM_PREAMBLE_LEN] = {0, 0, 0, 0, 1, 0, 1, 0};
if (!preambleSearchEx(DemodBuffer, preamble, EM_PREAMBLE_LEN, &size, &startIdx, true)) {
//try psk1 inverted
ans = PSKDemod(0, 1, 6, false);
@ -218,7 +233,13 @@ static bool detectPSK(void) {
PrintAndLogEx(DEBUG, "DEBUG: Error - EM: PSK1 inverted Demod failed");
return false;
}
if (!preambleSearchEx(DemodBuffer, preamble, EM_PREAMBLE_LEN, &size, &startIdx, true)) {
PrintAndLogEx(DEBUG, "DEBUG: Error - EM: PSK1 inverted Demod failed 2");
return false;
}
}
// either PSK1 or PSK1 inverted is ok from here.
// lets check PSK2 later.
return true;
@ -324,6 +345,11 @@ static int em4x05_demod_resp(uint32_t *word, bool onlyPreamble) {
res = doPreambleSearch(&idx);
if (res == PM3_SUCCESS)
break;
res = doPreambleSearch(&idx);
if (res == PM3_SUCCESS)
break;
if (res == PM3_EFAILED)
found_err = true;
@ -331,9 +357,15 @@ static int em4x05_demod_resp(uint32_t *word, bool onlyPreamble) {
res = doPreambleSearch(&idx);
if (res == PM3_SUCCESS)
break;
res = doPreambleSearch(&idx);
if (res == PM3_SUCCESS)
break;
if (res == PM3_EFAILED)
found_err = true;
}
if (found_err)
return PM3_EFAILED;
@ -1082,8 +1114,10 @@ int CmdEM4x05Info(const char *Cmd) {
// read word 4 (config block)
// needs password if one is set
if (em4x05_read_word_ext(EM_CONFIG_BLOCK, pwd, usePwd, &word) != PM3_SUCCESS)
if (em4x05_read_word_ext(EM_CONFIG_BLOCK, pwd, usePwd, &word) != PM3_SUCCESS) {
PrintAndLogEx(DEBUG, "(CmdEM4x05Info) failed to read CONFIG BLOCK");
return PM3_ESOFT;
}
printEM4x05config(word);