From f2ea55fb3c9946cb36620586b30dd3f302cfed26 Mon Sep 17 00:00:00 2001
From: marshmellow42 <marshmellowrf@gmail.com>
Date: Wed, 29 Mar 2017 10:02:29 -0400
Subject: [PATCH] fix/update removeParity & fix securakey detection
---
client/cmdlfsecurakey.c | 30 +++++++++++++++++-------------
common/lfdemod.c | 29 +++++++++++++----------------
2 files changed, 30 insertions(+), 29 deletions(-)
diff --git a/client/cmdlfsecurakey.c b/client/cmdlfsecurakey.c
index 1d55faf9..1e3899db 100644
--- a/client/cmdlfsecurakey.c
+++ b/client/cmdlfsecurakey.c
@@ -83,33 +83,37 @@ int CmdSecurakeyDemod(const char *Cmd) {
// y = card #
// standard wiegand parities.
// unknown checksum 11 bits? at the end
- uint8_t bits_no_spacer[86];
- memcpy(bits_no_spacer, DemodBuffer + 10, 86);
+ uint8_t bits_no_spacer[85];
+ memcpy(bits_no_spacer, DemodBuffer + 11, 85);
// remove marker bits (0's every 9th digit after preamble) (pType = 3 (always 0s))
- size = removeParity(bits_no_spacer, 0, 9, 3, 86);
- if ( size != 86-10 ) {
+ size = removeParity(bits_no_spacer, 0, 9, 3, 85);
+ if ( size != 85-9 ) {
if (g_debugMode) PrintAndLog("DEBUG: Error removeParity: %d", size);
return 0;
}
- uint8_t bitLen = (uint8_t)bytebits_to_byte(DemodBuffer+2, 6);
+ uint8_t bitLen = (uint8_t)bytebits_to_byte(bits_no_spacer+2, 6);
uint32_t fc=0, lWiegand=0, rWiegand=0;
- // get FC
+ if (bitLen > 40) { //securakey's max bitlen is 40 bits...
+ if (g_debugMode) PrintAndLog("DEBUG: Error bitLen too long: %u", bitLen);
+ return 0;
+ }
// get left 1/2 wiegand & right 1/2 wiegand (for parity test and wiegand print)
- lWiegand = bytebits_to_byte(DemodBuffer + 48 - bitLen, bitLen/2);
- rWiegand = bytebits_to_byte(DemodBuffer + 48 - bitLen + bitLen/2, bitLen/2);
- fc = bytebits_to_byte(DemodBuffer+49-bitLen, bitLen-2-16);
+ lWiegand = bytebits_to_byte(bits_no_spacer + 48 - bitLen, bitLen/2);
+ rWiegand = bytebits_to_byte(bits_no_spacer + 48 - bitLen + bitLen/2, bitLen/2);
+ // get FC
+ fc = bytebits_to_byte(bits_no_spacer+49-bitLen, bitLen-2-16);
// test bitLen
if (bitLen != 26 && bitLen != 32)
PrintAndLog("***unknown securakey bitLen - share with forum***");
- uint32_t cardid = bytebits_to_byte(DemodBuffer+8+23, 16);
- // test parities
- bool parity = evenparity32(lWiegand) && oddparity32(rWiegand);
+ uint32_t cardid = bytebits_to_byte(bits_no_spacer+8+23, 16);
+ // test parities - evenparity32 looks to add an even parity returns 0 if already even...
+ bool parity = !evenparity32(lWiegand) && !oddparity32(rWiegand);
- PrintAndLog("Securakey Tag Found--BitLen: %u, Card ID: %u, FC: %X, Raw: %08X%08X%08X", bitLen, cardid, fc, raw1 ,raw2, raw3);
+ PrintAndLog("Securakey Tag Found--BitLen: %u, Card ID: %u, FC: 0x%X, Raw: %08X%08X%08X", bitLen, cardid, fc, raw1 ,raw2, raw3);
if (bitLen <= 32)
PrintAndLog("Wiegand: %08X, Parity: %s", (lWiegand<<(bitLen/2)) | rWiegand, parity ? "Passed" : "Failed");
PrintAndLog("\nHow the FC translates to printed FC is unknown");
diff --git a/common/lfdemod.c b/common/lfdemod.c
index eb84203e..c56301c0 100644
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -35,6 +35,7 @@
#include <string.h> // for memset, memcmp and size_t
#include <stdint.h> // for uint_32+
#include <stdbool.h> // for bool
+#include "parity.h" // for parity test
//**********************************************************************************************
//---------------------------------Utilities Section--------------------------------------------
@@ -82,40 +83,35 @@ int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi
// by marshmellow
// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
// returns 1 if passed
-uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) {
- uint8_t ans = 0;
- for (uint8_t i = 0; i < bitLen; i++){
- ans ^= ((bits >> i) & 1);
- }
- if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
- return (ans == pType);
+bool parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) {
+ return oddparity32(bits) ^ pType;
}
// by marshmellow
-// takes a array of binary values, start position, length of bits per parity (includes parity bit),
-// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
+// takes a array of binary values, start position, length of bits per parity (includes parity bit - MAX 32),
+// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) {
uint32_t parityWd = 0;
- size_t j = 0, bitCnt = 0;
+ size_t bitCnt = 0;
for (int word = 0; word < (bLen); word+=pLen) {
for (int bit=0; bit < pLen; bit++) {
+ if (word+bit >= bLen) break;
parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
- BitStream[j++] = (BitStream[startIdx+word+bit]);
+ BitStream[bitCnt++] = (BitStream[startIdx+word+bit]);
}
if (word+pLen > bLen) break;
- j--; // overwrite parity with next data
+ bitCnt--; // overwrite parity with next data
// if parity fails then return 0
switch (pType) {
- case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit
- case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit
+ case 3: if (BitStream[bitCnt]==1) {return 0;} break; //should be 0 spacer bit
+ case 2: if (BitStream[bitCnt]==0) {return 0;} break; //should be 1 spacer bit
default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
}
- bitCnt+=(pLen-1);
parityWd = 0;
}
// if we got here then all the parities passed
- //return ID start index and size
+ //return size
return bitCnt;
}
@@ -1687,6 +1683,7 @@ uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_
*hi = (bytebits_to_byte(BitStream, 24));
*lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
} else {
+ if (g_debugMode) prnt("Error removing parity: %u", *size);
return 0;
}
return 1;
--
2.39.5