started fixing the paritiy == 0 special attack against chinese clones with bad prng...

[proxmark3-svn] / armsrc / pcf7931.c

diff --git a/armsrc/pcf7931.c b/armsrc/pcf7931.c
index 2b23bc36b79db95cd98c205578d933869ab1af0e..799167e991fc5159075f5873d2e579531d8b8aea 100644 (file)
--- a/armsrc/pcf7931.c
+++ b/armsrc/pcf7931.c
@@ -7,9 +7,6 @@
 #define T0_PCF 8 //period for the pcf7931 in us
 #define ALLOC 16
 
-#define abs(x) ( ((x)<0) ? -(x) : (x) )
-#define max(x,y) ( x<y ? y:x)
-
 int DemodPCF7931(uint8_t **outBlocks) {
 
     uint8_t bits[256] = {0x00};
@@ -28,6 +25,8 @@ int DemodPCF7931(uint8_t **outBlocks) {
        int num_blocks = 0;
        int lmin=128, lmax=128;
        uint8_t dir;
+       //clear read buffer
+       BigBuf_Clear_keep_EM();
 
        LFSetupFPGAForADC(95, true);
        DoAcquisition_default(0, true);
@@ -69,7 +68,7 @@ int DemodPCF7931(uint8_t **outBlocks) {
 
                        // Switch depending on lc length:
                        // Tolerance is 1/8 of clock rate (arbitrary)
-                       if (abs(lc-clock/4) < tolerance) {
+                       if (ABS(lc-clock/4) < tolerance) {
                                // 16T0
                                if((i - pmc) == lc) { /* 16T0 was previous one */
                                        /* It's a PMC ! */
@@ -81,7 +80,7 @@ int DemodPCF7931(uint8_t **outBlocks) {
                                else {
                                        pmc = i;
                                }
-                       } else if (abs(lc-clock/2) < tolerance) {
+                       } else if (ABS(lc-clock/2) < tolerance) {
                                // 32TO
                                if((i - pmc) == lc) { /* 16T0 was previous one */
                                        /* It's a PMC ! */
@@ -96,7 +95,7 @@ int DemodPCF7931(uint8_t **outBlocks) {
                                }
                                else
                                        half_switch++;
-                       } else if (abs(lc-clock) < tolerance) {
+                       } else if (ABS(lc-clock) < tolerance) {
                                // 64TO
                 bits[bitidx++] = 1;
                        } else {
@@ -203,7 +202,7 @@ void ReadPCF7931() {
                                                Blocks[0][ALLOC] = 1;
                                                memcpy(Blocks[1], tmpBlocks[i+1], 16);
                                                Blocks[1][ALLOC] = 1;
-                                               max_blocks = max((Blocks[1][14] & 0x7f), Blocks[1][15]) + 1;
+                                               max_blocks = MAX((Blocks[1][14] & 0x7f), Blocks[1][15]) + 1;
                                                // Debug print
                                                Dbprintf("(dbg) Max blocks: %d", max_blocks);
                                                num_blocks = 2;
@@ -386,10 +385,9 @@ void WritePCF7931(uint8_t pass1, uint8_t pass2, uint8_t pass3, uint8_t pass4, ui
  */
 
 void SendCmdPCF7931(uint32_t * tab){
-       uint16_t u=0;
-       uint16_t tempo=0;
+       uint16_t u=0, tempo=0;
 
-       Dbprintf("SENDING DATA FRAME...");
+       Dbprintf("Sending data frame...");
 
        FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 
@@ -413,27 +411,19 @@ void SendCmdPCF7931(uint32_t * tab){
 
 
        tempo = AT91C_BASE_TC0->TC_CV;
-       for(u=0;tab[u]!= 0;u+=3){
-
+       for( u = 0; tab[u] != 0; u += 3){
 
                // modulate antenna
                HIGH(GPIO_SSC_DOUT);
-               while(tempo !=  tab[u]){
-                       tempo = AT91C_BASE_TC0->TC_CV;
-               }
+               while(tempo != tab[u]) tempo = AT91C_BASE_TC0->TC_CV;           
 
                // stop modulating antenna
                LOW(GPIO_SSC_DOUT);
-               while(tempo !=  tab[u+1]){
-                       tempo = AT91C_BASE_TC0->TC_CV;
-               }
-
+               while(tempo != tab[u+1]) tempo = AT91C_BASE_TC0->TC_CV;
 
                // modulate antenna
                HIGH(GPIO_SSC_DOUT);
-               while(tempo !=  tab[u+2]){
-                       tempo = AT91C_BASE_TC0->TC_CV;
-               }
+               while(tempo != tab[u+2]) tempo = AT91C_BASE_TC0->TC_CV;         
        }
 
        LED_A_OFF();
@@ -455,7 +445,7 @@ void SendCmdPCF7931(uint32_t * tab){
 bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p){
 
        uint32_t u;
-       for (u=0; u<8; u++)
+       for ( u=0; u<8; u++)
        {
                if (byte&(1<<u)) {      //bit à 1
                        if( AddBitPCF7931(1, tab, l, p)==1) return 1;
@@ -463,7 +453,6 @@ bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p){
                        if (AddBitPCF7931(0, tab, l, p)==1) return 1;
                }
        }
-
        return 0;
 }
 
@@ -485,16 +474,18 @@ bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p){
                else
                        tab[u] = 34 * T0_PCF + tab[u-1] + p;
 
-               tab[u+1] = 6 * T0_PCF + tab[u] + l;
+               tab[u+1] =  6 * T0_PCF + tab[u] + l;
                tab[u+2] = 88 * T0_PCF + tab[u+1] - l - p;
                return 0;
        } else {                //add a bit 0
 
-               if(u==0) tab[u] = 98*T0_PCF+p;
-               else     tab[u] = 98*T0_PCF+tab[u-1]+p;
+               if ( u == 0 )
+                       tab[u] = 98 * T0_PCF + p;
+               else
+                       tab[u] = 98 * T0_PCF + tab[u-1] + p;
 
-               tab[u+1] = 6*T0_PCF+tab[u]+l;
-               tab[u+2] = 24*T0_PCF+tab[u+1]-l-p;
+               tab[u+1] =  6 * T0_PCF + tab[u] + l;
+               tab[u+2] = 24 * T0_PCF + tab[u+1] - l - p;
                return 0;
        }
 
@@ -510,13 +501,11 @@ bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p){
  */
 bool AddPatternPCF7931(uint32_t a, uint32_t b, uint32_t c, uint32_t * tab){
        uint32_t u = 0;
-       for(u=0;tab[u]!=0;u+=3){} //we put the cursor at the last value of the array
-
-       if(u==0) tab[u] = a;
-       else tab[u] = a + tab[u-1];
+       for(u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
 
-       tab[u+1] = b+tab[u];
-       tab[u+2] = c+tab[u+1];
+       tab[u]   = (u == 0) ? a : a + tab[u-1];
+       tab[u+1] = b + tab[u];
+       tab[u+2] = c + tab[u+1];
 
        return 0;
 }
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