| 1 | //----------------------------------------------------------------------------- |
| 2 | // Copyright (C) 2010 iZsh <izsh at fail0verflow.com> |
| 3 | // |
| 4 | // This code is licensed to you under the terms of the GNU GPL, version 2 or, |
| 5 | // at your option, any later version. See the LICENSE.txt file for the text of |
| 6 | // the license. |
| 7 | //----------------------------------------------------------------------------- |
| 8 | // Low frequency EM4x commands |
| 9 | //----------------------------------------------------------------------------- |
| 10 | |
| 11 | #include <stdio.h> |
| 12 | #include <string.h> |
| 13 | #include "proxusb.h" |
| 14 | #include "ui.h" |
| 15 | #include "graph.h" |
| 16 | #include "cmdparser.h" |
| 17 | #include "cmddata.h" |
| 18 | #include "cmdlf.h" |
| 19 | #include "cmdlfem4x.h" |
| 20 | |
| 21 | static int CmdHelp(const char *Cmd); |
| 22 | |
| 23 | /* Read the ID of an EM410x tag. |
| 24 | * Format: |
| 25 | * 1111 1111 1 <-- standard non-repeatable header |
| 26 | * XXXX [row parity bit] <-- 10 rows of 5 bits for our 40 bit tag ID |
| 27 | * .... |
| 28 | * CCCC <-- each bit here is parity for the 10 bits above in corresponding column |
| 29 | * 0 <-- stop bit, end of tag |
| 30 | */ |
| 31 | int CmdEM410xRead(const char *Cmd) |
| 32 | { |
| 33 | int i, j, clock, header, rows, bit, hithigh, hitlow, first, bit2idx, high, low; |
| 34 | int parity[4]; |
| 35 | char id[11]; |
| 36 | int retested = 0; |
| 37 | uint8_t BitStream[MAX_GRAPH_TRACE_LEN]; |
| 38 | high = low = 0; |
| 39 | |
| 40 | /* Detect high and lows and clock */ |
| 41 | for (i = 0; i < GraphTraceLen; i++) |
| 42 | { |
| 43 | if (GraphBuffer[i] > high) |
| 44 | high = GraphBuffer[i]; |
| 45 | else if (GraphBuffer[i] < low) |
| 46 | low = GraphBuffer[i]; |
| 47 | } |
| 48 | |
| 49 | /* get clock */ |
| 50 | clock = GetClock(Cmd, high, 0); |
| 51 | |
| 52 | /* parity for our 4 columns */ |
| 53 | parity[0] = parity[1] = parity[2] = parity[3] = 0; |
| 54 | header = rows = 0; |
| 55 | |
| 56 | /* manchester demodulate */ |
| 57 | bit = bit2idx = 0; |
| 58 | for (i = 0; i < (int)(GraphTraceLen / clock); i++) |
| 59 | { |
| 60 | hithigh = 0; |
| 61 | hitlow = 0; |
| 62 | first = 1; |
| 63 | |
| 64 | /* Find out if we hit both high and low peaks */ |
| 65 | for (j = 0; j < clock; j++) |
| 66 | { |
| 67 | if (GraphBuffer[(i * clock) + j] == high) |
| 68 | hithigh = 1; |
| 69 | else if (GraphBuffer[(i * clock) + j] == low) |
| 70 | hitlow = 1; |
| 71 | |
| 72 | /* it doesn't count if it's the first part of our read |
| 73 | because it's really just trailing from the last sequence */ |
| 74 | if (first && (hithigh || hitlow)) |
| 75 | hithigh = hitlow = 0; |
| 76 | else |
| 77 | first = 0; |
| 78 | |
| 79 | if (hithigh && hitlow) |
| 80 | break; |
| 81 | } |
| 82 | |
| 83 | /* If we didn't hit both high and low peaks, we had a bit transition */ |
| 84 | if (!hithigh || !hitlow) |
| 85 | bit ^= 1; |
| 86 | |
| 87 | BitStream[bit2idx++] = bit; |
| 88 | } |
| 89 | |
| 90 | retest: |
| 91 | /* We go till 5 before the graph ends because we'll get that far below */ |
| 92 | for (i = 1; i < bit2idx - 5; i++) |
| 93 | { |
| 94 | /* Step 2: We have our header but need our tag ID */ |
| 95 | if (header == 9 && rows < 10) |
| 96 | { |
| 97 | /* Confirm parity is correct */ |
| 98 | if ((BitStream[i] ^ BitStream[i+1] ^ BitStream[i+2] ^ BitStream[i+3]) == BitStream[i+4]) |
| 99 | { |
| 100 | /* Read another byte! */ |
| 101 | sprintf(id+rows, "%x", (8 * BitStream[i]) + (4 * BitStream[i+1]) + (2 * BitStream[i+2]) + (1 * BitStream[i+3])); |
| 102 | rows++; |
| 103 | |
| 104 | /* Keep parity info */ |
| 105 | parity[0] ^= BitStream[i]; |
| 106 | parity[1] ^= BitStream[i+1]; |
| 107 | parity[2] ^= BitStream[i+2]; |
| 108 | parity[3] ^= BitStream[i+3]; |
| 109 | |
| 110 | /* Move 4 bits ahead */ |
| 111 | i += 4; |
| 112 | } |
| 113 | |
| 114 | /* Damn, something wrong! reset */ |
| 115 | else |
| 116 | { |
| 117 | PrintAndLog("Thought we had a valid tag but failed at word %d (i=%d)", rows + 1, i); |
| 118 | |
| 119 | /* Start back rows * 5 + 9 header bits, -1 to not start at same place */ |
| 120 | i -= 9 + (5 * rows) - 5; |
| 121 | |
| 122 | rows = header = 0; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | /* Step 3: Got our 40 bits! confirm column parity */ |
| 127 | else if (rows == 10) |
| 128 | { |
| 129 | /* We need to make sure our 4 bits of parity are correct and we have a stop bit */ |
| 130 | if (BitStream[i] == parity[0] && BitStream[i+1] == parity[1] && |
| 131 | BitStream[i+2] == parity[2] && BitStream[i+3] == parity[3] && |
| 132 | BitStream[i+4] == 0) |
| 133 | { |
| 134 | /* Sweet! */ |
| 135 | PrintAndLog("EM410x Tag ID: %s", id); |
| 136 | |
| 137 | /* Stop any loops */ |
| 138 | return 1; |
| 139 | } |
| 140 | |
| 141 | /* Crap! Incorrect parity or no stop bit, start all over */ |
| 142 | else |
| 143 | { |
| 144 | rows = header = 0; |
| 145 | |
| 146 | /* Go back 59 bits (9 header bits + 10 rows at 4+1 parity) */ |
| 147 | i -= 59; |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | /* Step 1: get our header */ |
| 152 | else if (header < 9) |
| 153 | { |
| 154 | /* Need 9 consecutive 1's */ |
| 155 | if (BitStream[i] == 1) |
| 156 | header++; |
| 157 | |
| 158 | /* We don't have a header, not enough consecutive 1 bits */ |
| 159 | else |
| 160 | header = 0; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | /* if we've already retested after flipping bits, return */ |
| 165 | if (retested++) |
| 166 | return 0; |
| 167 | |
| 168 | /* if this didn't work, try flipping bits */ |
| 169 | for (i = 0; i < bit2idx; i++) |
| 170 | BitStream[i] ^= 1; |
| 171 | |
| 172 | goto retest; |
| 173 | } |
| 174 | |
| 175 | /* emulate an EM410X tag |
| 176 | * Format: |
| 177 | * 1111 1111 1 <-- standard non-repeatable header |
| 178 | * XXXX [row parity bit] <-- 10 rows of 5 bits for our 40 bit tag ID |
| 179 | * .... |
| 180 | * CCCC <-- each bit here is parity for the 10 bits above in corresponding column |
| 181 | * 0 <-- stop bit, end of tag |
| 182 | */ |
| 183 | int CmdEM410xSim(const char *Cmd) |
| 184 | { |
| 185 | int i, n, j, h, binary[4], parity[4]; |
| 186 | |
| 187 | /* clock is 64 in EM410x tags */ |
| 188 | int clock = 64; |
| 189 | |
| 190 | /* clear our graph */ |
| 191 | ClearGraph(0); |
| 192 | |
| 193 | /* write it out a few times */ |
| 194 | for (h = 0; h < 4; h++) |
| 195 | { |
| 196 | /* write 9 start bits */ |
| 197 | for (i = 0; i < 9; i++) |
| 198 | AppendGraph(0, clock, 1); |
| 199 | |
| 200 | /* for each hex char */ |
| 201 | parity[0] = parity[1] = parity[2] = parity[3] = 0; |
| 202 | for (i = 0; i < 10; i++) |
| 203 | { |
| 204 | /* read each hex char */ |
| 205 | sscanf(&Cmd[i], "%1x", &n); |
| 206 | for (j = 3; j >= 0; j--, n/= 2) |
| 207 | binary[j] = n % 2; |
| 208 | |
| 209 | /* append each bit */ |
| 210 | AppendGraph(0, clock, binary[0]); |
| 211 | AppendGraph(0, clock, binary[1]); |
| 212 | AppendGraph(0, clock, binary[2]); |
| 213 | AppendGraph(0, clock, binary[3]); |
| 214 | |
| 215 | /* append parity bit */ |
| 216 | AppendGraph(0, clock, binary[0] ^ binary[1] ^ binary[2] ^ binary[3]); |
| 217 | |
| 218 | /* keep track of column parity */ |
| 219 | parity[0] ^= binary[0]; |
| 220 | parity[1] ^= binary[1]; |
| 221 | parity[2] ^= binary[2]; |
| 222 | parity[3] ^= binary[3]; |
| 223 | } |
| 224 | |
| 225 | /* parity columns */ |
| 226 | AppendGraph(0, clock, parity[0]); |
| 227 | AppendGraph(0, clock, parity[1]); |
| 228 | AppendGraph(0, clock, parity[2]); |
| 229 | AppendGraph(0, clock, parity[3]); |
| 230 | |
| 231 | /* stop bit */ |
| 232 | AppendGraph(0, clock, 0); |
| 233 | } |
| 234 | |
| 235 | /* modulate that biatch */ |
| 236 | CmdManchesterMod(""); |
| 237 | |
| 238 | /* booyah! */ |
| 239 | RepaintGraphWindow(); |
| 240 | |
| 241 | CmdLFSim(""); |
| 242 | return 0; |
| 243 | } |
| 244 | |
| 245 | /* Function is equivalent of loread + losamples + em410xread |
| 246 | * looped until an EM410x tag is detected */ |
| 247 | int CmdEM410xWatch(const char *Cmd) |
| 248 | { |
| 249 | do |
| 250 | { |
| 251 | CmdLFRead(""); |
| 252 | CmdSamples("2000"); |
| 253 | } while ( ! CmdEM410xRead("")); |
| 254 | return 0; |
| 255 | } |
| 256 | |
| 257 | /* Read the transmitted data of an EM4x50 tag |
| 258 | * Format: |
| 259 | * |
| 260 | * XXXXXXXX [row parity bit (even)] <- 8 bits plus parity |
| 261 | * XXXXXXXX [row parity bit (even)] <- 8 bits plus parity |
| 262 | * XXXXXXXX [row parity bit (even)] <- 8 bits plus parity |
| 263 | * XXXXXXXX [row parity bit (even)] <- 8 bits plus parity |
| 264 | * CCCCCCCC <- column parity bits |
| 265 | * 0 <- stop bit |
| 266 | * LW <- Listen Window |
| 267 | * |
| 268 | * This pattern repeats for every block of data being transmitted. |
| 269 | * Transmission starts with two Listen Windows (LW - a modulated |
| 270 | * pattern of 320 cycles each (32/32/128/64/64)). |
| 271 | * |
| 272 | * Note that this data may or may not be the UID. It is whatever data |
| 273 | * is stored in the blocks defined in the control word First and Last |
| 274 | * Word Read values. UID is stored in block 32. |
| 275 | */ |
| 276 | int CmdEM4x50Read(const char *Cmd) |
| 277 | { |
| 278 | int i, j, startblock, skip, block, start, end, low, high; |
| 279 | bool complete= false; |
| 280 | int tmpbuff[MAX_GRAPH_TRACE_LEN / 64]; |
| 281 | char tmp[6]; |
| 282 | |
| 283 | high= low= 0; |
| 284 | memset(tmpbuff, 0, MAX_GRAPH_TRACE_LEN / 64); |
| 285 | |
| 286 | /* first get high and low values */ |
| 287 | for (i = 0; i < GraphTraceLen; i++) |
| 288 | { |
| 289 | if (GraphBuffer[i] > high) |
| 290 | high = GraphBuffer[i]; |
| 291 | else if (GraphBuffer[i] < low) |
| 292 | low = GraphBuffer[i]; |
| 293 | } |
| 294 | |
| 295 | /* populate a buffer with pulse lengths */ |
| 296 | i= 0; |
| 297 | j= 0; |
| 298 | while (i < GraphTraceLen) |
| 299 | { |
| 300 | // measure from low to low |
| 301 | while ((GraphBuffer[i] > low) && (i<GraphTraceLen)) |
| 302 | ++i; |
| 303 | start= i; |
| 304 | while ((GraphBuffer[i] < high) && (i<GraphTraceLen)) |
| 305 | ++i; |
| 306 | while ((GraphBuffer[i] > low) && (i<GraphTraceLen)) |
| 307 | ++i; |
| 308 | if (j>(MAX_GRAPH_TRACE_LEN/64)) { |
| 309 | break; |
| 310 | } |
| 311 | tmpbuff[j++]= i - start; |
| 312 | } |
| 313 | |
| 314 | /* look for data start - should be 2 pairs of LW (pulses of 192,128) */ |
| 315 | start= -1; |
| 316 | skip= 0; |
| 317 | for (i= 0; i < j - 4 ; ++i) |
| 318 | { |
| 319 | skip += tmpbuff[i]; |
| 320 | if (tmpbuff[i] >= 190 && tmpbuff[i] <= 194) |
| 321 | if (tmpbuff[i+1] >= 126 && tmpbuff[i+1] <= 130) |
| 322 | if (tmpbuff[i+2] >= 190 && tmpbuff[i+2] <= 194) |
| 323 | if (tmpbuff[i+3] >= 126 && tmpbuff[i+3] <= 130) |
| 324 | { |
| 325 | start= i + 3; |
| 326 | break; |
| 327 | } |
| 328 | } |
| 329 | startblock= i + 3; |
| 330 | |
| 331 | /* skip over the remainder of the LW */ |
| 332 | skip += tmpbuff[i+1]+tmpbuff[i+2]; |
| 333 | while (skip < MAX_GRAPH_TRACE_LEN && GraphBuffer[skip] > low) |
| 334 | ++skip; |
| 335 | skip += 8; |
| 336 | |
| 337 | /* now do it again to find the end */ |
| 338 | end= start; |
| 339 | for (i += 3; i < j - 4 ; ++i) |
| 340 | { |
| 341 | end += tmpbuff[i]; |
| 342 | if (tmpbuff[i] >= 190 && tmpbuff[i] <= 194) |
| 343 | if (tmpbuff[i+1] >= 126 && tmpbuff[i+1] <= 130) |
| 344 | if (tmpbuff[i+2] >= 190 && tmpbuff[i+2] <= 194) |
| 345 | if (tmpbuff[i+3] >= 126 && tmpbuff[i+3] <= 130) |
| 346 | { |
| 347 | complete= true; |
| 348 | break; |
| 349 | } |
| 350 | } |
| 351 | |
| 352 | if (start >= 0) |
| 353 | PrintAndLog("Found data at sample: %i",skip); |
| 354 | else |
| 355 | { |
| 356 | PrintAndLog("No data found!"); |
| 357 | PrintAndLog("Try again with more samples."); |
| 358 | return 0; |
| 359 | } |
| 360 | |
| 361 | if (!complete) |
| 362 | { |
| 363 | PrintAndLog("*** Warning!"); |
| 364 | PrintAndLog("Partial data - no end found!"); |
| 365 | PrintAndLog("Try again with more samples."); |
| 366 | } |
| 367 | |
| 368 | /* get rid of leading crap */ |
| 369 | sprintf(tmp,"%i",skip); |
| 370 | CmdLtrim(tmp); |
| 371 | |
| 372 | /* now work through remaining buffer printing out data blocks */ |
| 373 | block= 0; |
| 374 | i= startblock; |
| 375 | while (block < 6) |
| 376 | { |
| 377 | PrintAndLog("Block %i:", block); |
| 378 | // mandemod routine needs to be split so we can call it for data |
| 379 | // just print for now for debugging |
| 380 | CmdManchesterDemod("i 64"); |
| 381 | skip= 0; |
| 382 | /* look for LW before start of next block */ |
| 383 | for ( ; i < j - 4 ; ++i) |
| 384 | { |
| 385 | skip += tmpbuff[i]; |
| 386 | if (tmpbuff[i] >= 190 && tmpbuff[i] <= 194) |
| 387 | if (tmpbuff[i+1] >= 126 && tmpbuff[i+1] <= 130) |
| 388 | break; |
| 389 | } |
| 390 | while (GraphBuffer[skip] > low) |
| 391 | ++skip; |
| 392 | skip += 8; |
| 393 | sprintf(tmp,"%i",skip); |
| 394 | CmdLtrim(tmp); |
| 395 | start += skip; |
| 396 | block++; |
| 397 | } |
| 398 | return 0; |
| 399 | } |
| 400 | |
| 401 | int CmdEM410xWrite(const char *Cmd) |
| 402 | { |
| 403 | uint64_t id = 0; |
| 404 | unsigned int card; |
| 405 | |
| 406 | sscanf(Cmd, "%lx %d", &id, &card); |
| 407 | |
| 408 | if (id >= 0x10000000000) { |
| 409 | PrintAndLog("Error! Given EM410x ID is longer than 40 bits.\n"); |
| 410 | return 0; |
| 411 | } |
| 412 | |
| 413 | if (card > 1) { |
| 414 | PrintAndLog("Error! Bad card type selected.\n"); |
| 415 | return 0; |
| 416 | } |
| 417 | |
| 418 | PrintAndLog("Writing %s tag with UID 0x%010lx", card ? "T55x7":"T5555", id); |
| 419 | UsbCommand c = {CMD_EM410X_WRITE_TAG, {card, (uint32_t)(id >> 32), (uint32_t)id}}; |
| 420 | SendCommand(&c); |
| 421 | |
| 422 | return 0; |
| 423 | } |
| 424 | |
| 425 | static command_t CommandTable[] = |
| 426 | { |
| 427 | {"help", CmdHelp, 1, "This help"}, |
| 428 | {"em410xread", CmdEM410xRead, 1, "[clock rate] -- Extract ID from EM410x tag"}, |
| 429 | {"em410xsim", CmdEM410xSim, 0, "<UID> -- Simulate EM410x tag"}, |
| 430 | {"em410xwatch", CmdEM410xWatch, 0, "Watches for EM410x tags"}, |
| 431 | {"em410xwrite", CmdEM410xWrite, 1, "<UID> <'0' T5555> <'1' T55x7> -- Write EM410x UID to T5555(Q5) or T55x7 tag"}, |
| 432 | {"em4x50read", CmdEM4x50Read, 1, "Extract data from EM4x50 tag"}, |
| 433 | {NULL, NULL, 0, NULL} |
| 434 | }; |
| 435 | |
| 436 | int CmdLFEM4X(const char *Cmd) |
| 437 | { |
| 438 | CmdsParse(CommandTable, Cmd); |
| 439 | return 0; |
| 440 | } |
| 441 | |
| 442 | int CmdHelp(const char *Cmd) |
| 443 | { |
| 444 | CmdsHelp(CommandTable); |
| 445 | return 0; |
| 446 | } |