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1 | //----------------------------------------------------------------------------- |
2 | // |
3 | // This code is licensed to you under the terms of the GNU GPL, version 2 or, |
4 | // at your option, any later version. See the LICENSE.txt file for the text of |
5 | // the license. |
6 | //----------------------------------------------------------------------------- |
7 | // Low frequency G Prox II tag commands |
b9957414 |
8 | // Biphase, rf/ , 96 bits (unknown key calc + some bits) |
946a84c3 |
9 | //----------------------------------------------------------------------------- |
10 | #include <stdio.h> |
11 | #include <string.h> |
12 | #include <inttypes.h> |
13 | #include "cmdlfgproxii.h" |
14 | #include "proxmark3.h" |
15 | #include "ui.h" |
16 | #include "util.h" |
17 | #include "graph.h" |
18 | #include "cmdparser.h" |
19 | #include "cmddata.h" |
20 | #include "cmdmain.h" |
21 | #include "cmdlf.h" |
22 | #include "lfdemod.h" |
23 | static int CmdHelp(const char *Cmd); |
24 | |
25 | //by marshmellow |
26 | //attempts to demodulate and identify a G_Prox_II verex/chubb card |
27 | //WARNING: if it fails during some points it will destroy the DemodBuffer data |
28 | // but will leave the GraphBuffer intact. |
29 | //if successful it will push askraw data back to demod buffer ready for emulation |
30 | int CmdG_Prox_II_Demod(const char *Cmd) |
31 | { |
32 | if (!ASKbiphaseDemod(Cmd, false)){ |
33 | if (g_debugMode) PrintAndLog("Error gProxII: ASKbiphaseDemod failed 1st try"); |
34 | return 0; |
35 | } |
36 | size_t size = DemodBufferLen; |
37 | //call lfdemod.c demod for gProxII |
38 | int ans = gProxII_Demod(DemodBuffer, &size); |
39 | if (ans < 0){ |
40 | if (g_debugMode) PrintAndLog("Error gProxII_Demod"); |
41 | return 0; |
42 | } |
43 | //got a good demod of 96 bits |
44 | uint8_t ByteStream[8] = {0x00}; |
45 | uint8_t xorKey=0; |
46 | size_t startIdx = ans + 6; //start after 6 bit preamble |
47 | |
48 | uint8_t bits_no_spacer[90]; |
49 | //so as to not mess with raw DemodBuffer copy to a new sample array |
50 | memcpy(bits_no_spacer, DemodBuffer + startIdx, 90); |
51 | // remove the 18 (90/5=18) parity bits (down to 72 bits (96-6-18=72)) |
52 | size_t bitLen = removeParity(bits_no_spacer, 0, 5, 3, 90); //source, startloc, paritylen, ptype, length_to_run |
53 | if (bitLen != 72) { |
54 | if (g_debugMode) PrintAndLog("Error gProxII: spacer removal did not produce 72 bits: %u, start: %u", bitLen, startIdx); |
55 | return 0; |
56 | } |
57 | // get key and then get all 8 bytes of payload decoded |
58 | xorKey = (uint8_t)bytebits_to_byteLSBF(bits_no_spacer, 8); |
59 | for (size_t idx = 0; idx < 8; idx++) { |
60 | ByteStream[idx] = ((uint8_t)bytebits_to_byteLSBF(bits_no_spacer+8 + (idx*8),8)) ^ xorKey; |
61 | if (g_debugMode) PrintAndLog("byte %u after xor: %02x", (unsigned int)idx, ByteStream[idx]); |
62 | } |
63 | //now ByteStream contains 8 Bytes (64 bits) of decrypted raw tag data |
64 | // |
65 | uint8_t fmtLen = ByteStream[0]>>2; |
66 | uint32_t FC = 0; |
67 | uint32_t Card = 0; |
68 | //get raw 96 bits to print |
69 | uint32_t raw1 = bytebits_to_byte(DemodBuffer+ans,32); |
70 | uint32_t raw2 = bytebits_to_byte(DemodBuffer+ans+32, 32); |
71 | uint32_t raw3 = bytebits_to_byte(DemodBuffer+ans+64, 32); |
72 | |
73 | if (fmtLen==36){ |
74 | FC = ((ByteStream[3] & 0x7F)<<7) | (ByteStream[4]>>1); |
75 | Card = ((ByteStream[4]&1)<<19) | (ByteStream[5]<<11) | (ByteStream[6]<<3) | (ByteStream[7]>>5); |
76 | PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card); |
77 | } else if(fmtLen==26){ |
78 | FC = ((ByteStream[3] & 0x7F)<<1) | (ByteStream[4]>>7); |
79 | Card = ((ByteStream[4]&0x7F)<<9) | (ByteStream[5]<<1) | (ByteStream[6]>>7); |
80 | PrintAndLog("G-Prox-II Found: FmtLen %d, FC %u, Card %u", (int)fmtLen, FC, Card); |
81 | } else { |
82 | PrintAndLog("Unknown G-Prox-II Fmt Found: FmtLen %d",(int)fmtLen); |
83 | PrintAndLog("Decoded Raw: %s", sprint_hex(ByteStream, 8)); |
84 | } |
85 | PrintAndLog("Raw: %08x%08x%08x", raw1,raw2,raw3); |
9fe4507c |
86 | setDemodBuf(DemodBuffer, 96, ans); |
87 | setClockGrid(g_DemodClock, g_DemodStartIdx + (ans*g_DemodClock)); |
88 | |
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89 | return 1; |
90 | } |
91 | //by marshmellow |
92 | //see ASKDemod for what args are accepted |
93 | int CmdG_Prox_II_Read(const char *Cmd) { |
94 | // read lf silently |
b9957414 |
95 | lf_read(true, 10000); |
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96 | // demod and output viking ID |
97 | return CmdG_Prox_II_Demod(Cmd); |
98 | } |
99 | |
100 | static command_t CommandTable[] = { |
101 | {"help", CmdHelp, 1, "This help"}, |
102 | {"demod", CmdG_Prox_II_Demod, 1, "Demodulate a G Prox II tag from the GraphBuffer"}, |
103 | {"read", CmdG_Prox_II_Read, 0, "Attempt to read and Extract tag data from the antenna"}, |
104 | {NULL, NULL, 0, NULL} |
105 | }; |
106 | |
107 | int CmdLF_G_Prox_II(const char *Cmd) { |
108 | CmdsParse(CommandTable, Cmd); |
109 | return 0; |
110 | } |
111 | |
112 | int CmdHelp(const char *Cmd) { |
113 | CmdsHelp(CommandTable); |
114 | return 0; |
115 | } |