]> git.zerfleddert.de Git - proxmark3-svn/blobdiff - winsrc/command.cpp
Add checks in em4x50read to avoid segfaults in case loops go over the GraphTraceLen.
[proxmark3-svn] / winsrc / command.cpp
index b830922bed9111d3587a8a1008870ba94df347c8..454fbab2417b1ddff306eb647fee98ce602ce862 100644 (file)
@@ -12,6 +12,7 @@
 \r
 #include "prox.h"\r
 #include "../common/iso14443_crc.c"\r
+#include "../common/crc16.c"\r
 \r
 #define arraylen(x) (sizeof(x)/sizeof((x)[0]))\r
 #define BIT(x) GraphBuffer[x * clock]\r
@@ -300,17 +301,19 @@ static void CmdEM4x50read(char *str)
        while(i < GraphTraceLen)\r
                {\r
                // measure from low to low\r
-               while(GraphBuffer[i] > low)\r
+               while((GraphBuffer[i] > low) && (i<GraphTraceLen))\r
                        ++i;\r
                start= i;\r
-               while(GraphBuffer[i] < high)\r
+               while((GraphBuffer[i] < high) && (i<GraphTraceLen))\r
                        ++i;\r
-               while(GraphBuffer[i] > low)\r
+               while((GraphBuffer[i] > low) && (i<GraphTraceLen))\r
                        ++i;\r
+               if (j>(MAX_GRAPH_TRACE_LEN/64)) {\r
+                       break;\r
+               }\r
                tmpbuff[j++]= i - start;\r
                }\r
 \r
-\r
        /* look for data start - should be 2 pairs of LW (pulses of 192,128) */\r
        start= -1;\r
        skip= 0;\r
@@ -330,7 +333,7 @@ static void CmdEM4x50read(char *str)
 \r
        /* skip over the remainder of the LW */\r
        skip += tmpbuff[i+1]+tmpbuff[i+2];\r
-       while(GraphBuffer[skip] > low)\r
+       while(skip < MAX_GRAPH_TRACE_LEN && GraphBuffer[skip] > low)\r
                ++skip;\r
        skip += 8;\r
 \r
@@ -1394,14 +1397,14 @@ static void CmdHi15demod(char *str)
        PrintToScrollback("CRC=%04x", Iso15693Crc(outBuf, k-2));\r
 }\r
 \r
-static void CmdTiread(char *str)\r
+static void CmdTIReadRaw(char *str)\r
 {\r
        UsbCommand c;\r
        c.cmd = CMD_ACQUIRE_RAW_BITS_TI_TYPE;\r
        SendCommand(&c, FALSE);\r
 }\r
 \r
-static void CmdTibits(char *str)\r
+static void CmdTIBits(char *str)\r
 {\r
        int cnt = 0;\r
        int i;\r
@@ -1553,7 +1556,30 @@ static void CmdFSKdemod(char *cmdline)
        PrintToScrollback("hex: %08x %08x", hi, lo);\r
 }\r
 \r
-static void CmdTidemod(char *cmdline)\r
+// read a TI tag and return its ID\r
+static void CmdTIRead(char *str)\r
+{\r
+       UsbCommand c;\r
+       c.cmd = CMD_READ_TI_TYPE;\r
+       SendCommand(&c, FALSE);\r
+}\r
+\r
+// write new data to a r/w TI tag\r
+static void CmdTIWrite(char *str)\r
+{\r
+       UsbCommand c;\r
+       int res=0;\r
+\r
+       c.cmd = CMD_WRITE_TI_TYPE;\r
+       res = sscanf(str, "0x%x 0x%x 0x%x ", &c.ext1, &c.ext2, &c.ext3);\r
+       if (res == 2) c.ext3=0;\r
+       if (res<2)\r
+               PrintToScrollback("Please specify 2 or three hex strings, eg 0x1234 0x5678");\r
+       else\r
+               SendCommand(&c, FALSE);\r
+}\r
+\r
+static void CmdTIDemod(char *cmdline)\r
 {\r
        /* MATLAB as follows:\r
 f_s = 2000000;  % sampling frequency\r
@@ -1608,8 +1634,8 @@ h = sign(sin(cumsum(h)));
  };\r
 \r
        int convLen = max(arraylen(HighTone), arraylen(LowTone));\r
-\r
-       int i;\r
+       WORD crc;\r
+       int i, TagType;\r
        for(i = 0; i < GraphTraceLen - convLen; i++) {\r
                int j;\r
                int lowSum = 0, highSum = 0;;\r
@@ -1644,17 +1670,29 @@ h = sign(sin(cumsum(h)));
 \r
        RepaintGraphWindow();\r
 \r
-       // Okay, so now we have unsliced soft decisions; find bit-sync, and then\r
-       // get some bits.\r
+       // TI tag data format is 16 prebits, 8 start bits, 64 data bits,\r
+       // 16 crc CCITT bits, 8 stop bits, 15 end bits\r
+\r
+       // the 16 prebits are always low\r
+       // the 8 start and stop bits of a tag must match\r
+       // the start/stop prebits of a ro tag are 01111110\r
+       // the start/stop prebits of a rw tag are 11111110\r
+  // the 15 end bits of a ro tag are all low\r
+  // the 15 end bits of a rw tag match bits 15-1 of the data bits\r
 \r
+       // Okay, so now we have unsliced soft decisions;\r
+       // find bit-sync, and then get some bits.\r
+       // look for 17 low bits followed by 6 highs (common pattern for ro and rw tags)\r
        int max = 0, maxPos = 0;\r
        for(i = 0; i < 6000; i++) {\r
                int j;\r
                int dec = 0;\r
-               for(j = 0; j < 8*arraylen(LowTone); j++) {\r
+               // searching 17 consecutive lows\r
+               for(j = 0; j < 17*arraylen(LowTone); j++) {\r
                        dec -= GraphBuffer[i+j];\r
                }\r
-               for(; j < 8*arraylen(LowTone) + 8*arraylen(HighTone); j++) {\r
+               // searching 7 consecutive highs\r
+               for(; j < 17*arraylen(LowTone) + 6*arraylen(HighTone); j++) {\r
                        dec += GraphBuffer[i+j];\r
                }\r
                if(dec > max) {\r
@@ -1662,14 +1700,18 @@ h = sign(sin(cumsum(h)));
                        maxPos = i;\r
                }\r
        }\r
-       GraphBuffer[maxPos] = 800;\r
-       GraphBuffer[maxPos+1] = -800;\r
 \r
-       maxPos += 8*arraylen(LowTone);\r
+       // place a marker in the buffer to visually aid location\r
+       // of the start of sync\r
        GraphBuffer[maxPos] = 800;\r
        GraphBuffer[maxPos+1] = -800;\r
-       maxPos += 8*arraylen(HighTone);\r
 \r
+       // advance pointer to start of actual data stream (after 16 pre and 8 start bits)\r
+       maxPos += 17*arraylen(LowTone);\r
+       maxPos += 6*arraylen(HighTone);\r
+\r
+       // place a marker in the buffer to visually aid location\r
+       // of the end of sync\r
        GraphBuffer[maxPos] = 800;\r
        GraphBuffer[maxPos+1] = -800;\r
 \r
@@ -1677,10 +1719,12 @@ h = sign(sin(cumsum(h)));
 \r
        PrintToScrollback("length %d/%d", arraylen(HighTone), arraylen(LowTone));\r
 \r
-       BYTE bits[64+16+8+1];\r
+       BYTE bits[1+64+16+8+16];\r
        bits[sizeof(bits)-1] = '\0';\r
 \r
-       for(i = 0; i < arraylen(bits); i++) {\r
+       DWORD shift3 = 0x7e000000, shift2 = 0, shift1 = 0, shift0 = 0;\r
+\r
+       for(i = 0; i < arraylen(bits)-1; i++) {\r
                int high = 0;\r
                int low = 0;\r
                int j;\r
@@ -1690,30 +1734,79 @@ h = sign(sin(cumsum(h)));
                for(j = 0; j < arraylen(HighTone); j++) {\r
                        high += GraphBuffer[maxPos+j];\r
                }\r
+\r
                if(high > low) {\r
                        bits[i] = '1';\r
                        maxPos += arraylen(HighTone);\r
+                       // bitstream arrives lsb first so shift right\r
+                       shift3 |= (1<<31);\r
                } else {\r
                        bits[i] = '.';\r
                        maxPos += arraylen(LowTone);\r
                }\r
+\r
+               // 128 bit right shift register\r
+         shift0 = (shift0>>1) | (shift1 << 31);\r
+         shift1 = (shift1>>1) | (shift2 << 31);\r
+         shift2 = (shift2>>1) | (shift3 << 31);\r
+         shift3 >>= 1;\r
+\r
+               // place a marker in the buffer between bits to visually aid location\r
                GraphBuffer[maxPos] = 800;\r
                GraphBuffer[maxPos+1] = -800;\r
        }\r
-       PrintToScrollback("bits: '%s'", bits);\r
+       PrintToScrollback("Info: raw tag bits = %s", bits);\r
 \r
-       DWORD h = 0, l = 0;\r
-       for(i = 0; i < 32; i++) {\r
-               if(bits[i] == '1') {\r
-                       l |= (1<<i);\r
-               }\r
+       TagType = (shift3>>8)&0xff;\r
+       if ( TagType != ((shift0>>16)&0xff) ) {\r
+               PrintToScrollback("Error: start and stop bits do not match!");\r
+               return;\r
+       }\r
+       else if (TagType == 0x7e) {\r
+               PrintToScrollback("Info: Readonly TI tag detected.");\r
+               return;\r
        }\r
-       for(i = 32; i < 64; i++) {\r
-               if(bits[i] == '1') {\r
-                       h |= (1<<(i-32));\r
+       else if (TagType == 0xfe) {\r
+               PrintToScrollback("Info: Rewriteable TI tag detected.");\r
+\r
+         // put 64 bit data into shift1 and shift0\r
+         shift0 = (shift0>>24) | (shift1 << 8);\r
+         shift1 = (shift1>>24) | (shift2 << 8);\r
+\r
+               // align 16 bit crc into lower half of shift2\r
+         shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;\r
+\r
+               // align 16 bit "end bits" or "ident" into lower half of shift3\r
+         shift3 >>= 16;\r
+\r
+               // only 15 bits compare, last bit of ident is not valid\r
+               if ( (shift3^shift0)&0x7fff ) {\r
+                       PrintToScrollback("Error: Ident mismatch!");\r
+               }\r
+               // WARNING the order of the bytes in which we calc crc below needs checking\r
+               // i'm 99% sure the crc algorithm is correct, but it may need to eat the\r
+               // bytes in reverse or something\r
+               // calculate CRC\r
+               crc=0;\r
+               crc = update_crc16(crc, (shift0)&0xff);\r
+               crc = update_crc16(crc, (shift0>>8)&0xff);\r
+               crc = update_crc16(crc, (shift0>>16)&0xff);\r
+               crc = update_crc16(crc, (shift0>>24)&0xff);\r
+               crc = update_crc16(crc, (shift1)&0xff);\r
+               crc = update_crc16(crc, (shift1>>8)&0xff);\r
+               crc = update_crc16(crc, (shift1>>16)&0xff);\r
+               crc = update_crc16(crc, (shift1>>24)&0xff);\r
+               PrintToScrollback("Info: Tag data = %08X%08X", shift1, shift0);\r
+               if (crc != (shift2&0xffff)) {\r
+                       PrintToScrollback("Error: CRC mismatch, calculated %04X, got ^04X", crc, shift2&0xffff);\r
+               } else {\r
+                       PrintToScrollback("Info: CRC %04X is good", crc);\r
                }\r
        }\r
-       PrintToScrollback("hex: %08x %08x", h, l);\r
+       else {\r
+               PrintToScrollback("Unknown tag type.");\r
+               return;\r
+       }\r
 }\r
 \r
 static void CmdNorm(char *str)\r
@@ -2720,7 +2813,7 @@ static struct {
        {"autocorr",                    CmdAutoCorr,                            1, "<window length> -- Autocorrelation over window"},\r
        {"bitsamples",          CmdBitsamples,                  0, "Get raw samples as bitstring"},\r
        {"bitstream",                   Cmdbitstream,                           1, "[clock rate] -- Convert waveform into a bitstream"},\r
-       {"buffclear",                   CmdBuffClear,                           0, "Clear sample buffer and graph window"},\r
+       {"buffclear",                   CmdBuffClear,                           1, "Clear sample buffer and graph window"},\r
        {"dec",                                         CmdDec,                                                 1, "Decimate samples"},\r
        {"detectclock",         Cmddetectclockrate,     1, "Detect clock rate"},\r
        {"detectreader",        CmdDetectReader,                0, "['l'|'h'] -- Detect external reader field (option 'l' or 'h' to limit to LF or HF)"},\r
@@ -2777,9 +2870,11 @@ static struct {
        {"scale",                                       CmdScale,                                               1, "<int> -- Set cursor display scale"},\r
        {"setlfdivisor",        CmdSetDivisor,                  0, "<19 - 255> -- Drive LF antenna at 12Mhz/(divisor+1)"},\r
        {"sri512read",          CmdSri512read,                  0, "<int> -- Read contents of a SRI512 tag"},\r
-       {"tibits",                              CmdTibits,                                      0, "Get raw bits for TI-type LF tag"},\r
-       {"tidemod",                             CmdTidemod,                                     1, "Demodulate raw bits for TI-type LF tag"},\r
-       {"tiread",                              CmdTiread,                                      0, "Read a TI-type 134 kHz tag"},\r
+       {"tibits",                              CmdTIBits,                                      0, "Get raw bits for TI-type LF tag"},\r
+       {"tidemod",                             CmdTIDemod,                                     1, "Demodulate raw bits for TI-type LF tag"},\r
+       {"tireadraw",                   CmdTIReadRaw,                           0, "Read a TI-type 134 kHz tag in raw mode"},\r
+       {"tiread",                              CmdTIRead,                                      0, "Read and decode a TI 134 kHz tag"},\r
+       {"tiwrite",                             CmdTIWrite,                                     0, "Write new data to a r/w TI 134 kHz tag"},\r
        {"threshold",                   CmdThreshold,                           1, "Maximize/minimize every value in the graph window depending on threshold"},\r
        {"tune",                                        CmdTune,                                                0, "Measure antenna tuning"},\r
        {"vchdemod",                    CmdVchdemod,                            0, "['clone'] -- Demodulate samples for VeriChip"},\r
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