| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: keygen.c,v 1.1 1997/07/21 13:47:48 mdw Exp $ |
| 4 | * |
| 5 | * Key generation |
| 6 | * |
| 7 | * (c) 1997 EBI |
| 8 | */ |
| 9 | |
| 10 | /*----- Licencing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of `become' |
| 13 | * |
| 14 | * `Become' is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU General Public License as published by |
| 16 | * the Free Software Foundation; either version 2 of the License, or |
| 17 | * (at your option) any later version. |
| 18 | * |
| 19 | * `Become' is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public License |
| 25 | * along with `become'; if not, write to the Free Software |
| 26 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 27 | */ |
| 28 | |
| 29 | /*----- Revision history --------------------------------------------------* |
| 30 | * |
| 31 | * $Log: keygen.c,v $ |
| 32 | * Revision 1.1 1997/07/21 13:47:48 mdw |
| 33 | * Initial revision |
| 34 | * |
| 35 | */ |
| 36 | |
| 37 | /*----- Header files ------------------------------------------------------*/ |
| 38 | |
| 39 | /* --- ANSI headers --- */ |
| 40 | |
| 41 | #include <ctype.h> |
| 42 | #include <errno.h> |
| 43 | #include <signal.h> |
| 44 | #include <stdio.h> |
| 45 | #include <stdlib.h> |
| 46 | #include <string.h> |
| 47 | |
| 48 | /* --- Unix headers --- */ |
| 49 | |
| 50 | #include <sys/types.h> |
| 51 | #include <sys/time.h> |
| 52 | #include <fcntl.h> |
| 53 | |
| 54 | #include <termios.h> |
| 55 | #include <unistd.h> |
| 56 | |
| 57 | /* --- Local headers --- */ |
| 58 | |
| 59 | #include "config.h" |
| 60 | #include "tx.h" |
| 61 | #include "mdwopt.h" |
| 62 | #include "utils.h" |
| 63 | |
| 64 | /*----- Static variables --------------------------------------------------*/ |
| 65 | |
| 66 | static struct termios kg__raw, kg__old; /* Terminal settings */ |
| 67 | static int kg__tty; /* File handle for the terminal */ |
| 68 | static FILE *kg__ttyfp; /* Stream pointer for terminal */ |
| 69 | static unsigned int kg__flags; /* Various interesting flags */ |
| 70 | |
| 71 | enum { |
| 72 | kgFlag__cbreak = 1 /* Terminal is in cbreak mode */ |
| 73 | }; |
| 74 | |
| 75 | /*----- Main code ---------------------------------------------------------*/ |
| 76 | |
| 77 | /* --- @kg__cbreak@ --- * |
| 78 | * |
| 79 | * Arguments: --- |
| 80 | * |
| 81 | * Returns: --- |
| 82 | * |
| 83 | * Use: Makes the terminal return characters as soon as they're |
| 84 | * asked for. |
| 85 | */ |
| 86 | |
| 87 | void kg__cbreak(void) |
| 88 | { |
| 89 | /* --- Don't do this if I don't have to --- */ |
| 90 | |
| 91 | if (kg__flags & kgFlag__cbreak) |
| 92 | return; |
| 93 | |
| 94 | /* --- Fetch the old attributes, and remember them --- */ |
| 95 | |
| 96 | if (tcgetattr(kg__tty, &kg__old)) |
| 97 | die("couldn't read terminal attributes: %s", strerror(errno)); |
| 98 | memcpy(&kg__raw, &kg__old, sizeof(kg__raw)); |
| 99 | |
| 100 | /* --- Now modify them for raw mode --- */ |
| 101 | |
| 102 | kg__raw.c_lflag &= ~(ICANON | ECHO); |
| 103 | kg__raw.c_cc[VTIME] = 0; |
| 104 | kg__raw.c_cc[VMIN] = 1; |
| 105 | |
| 106 | /* --- Remember the new state, and away we go --- */ |
| 107 | |
| 108 | kg__flags |= kgFlag__cbreak; |
| 109 | if (tcsetattr(kg__tty, TCSAFLUSH, &kg__raw)) |
| 110 | die("couldn't set terminal attributes: %s", strerror(errno)); |
| 111 | } |
| 112 | |
| 113 | /* --- @kg__crepair@ --- * |
| 114 | * |
| 115 | * Arguments: --- |
| 116 | * |
| 117 | * Returns: --- |
| 118 | * |
| 119 | * Use: Unbreaks a cbroken tty. Obvious, innit? |
| 120 | */ |
| 121 | |
| 122 | static void kg__crepair(void) |
| 123 | { |
| 124 | /* --- Don't do this if I don't have to --- */ |
| 125 | |
| 126 | if (~kg__flags & kgFlag__cbreak) |
| 127 | return; |
| 128 | |
| 129 | /* --- Reset the old attributes --- */ |
| 130 | |
| 131 | tcsetattr(kg__tty, TCSAFLUSH, &kg__old); |
| 132 | kg__flags &= ~kgFlag__cbreak; |
| 133 | } |
| 134 | |
| 135 | /* --- @kg__signal@ --- * |
| 136 | * |
| 137 | * Arguments: @int sig@ = signal number |
| 138 | * |
| 139 | * Returns: --- |
| 140 | * |
| 141 | * Use: Tidies up if I get a signal. |
| 142 | */ |
| 143 | |
| 144 | static void kg__signal(int sig) |
| 145 | { |
| 146 | kg__crepair(); |
| 147 | signal(sig, SIG_DFL); |
| 148 | raise(sig); |
| 149 | } |
| 150 | |
| 151 | /* --- @kgFmt__binary@ --- * |
| 152 | * |
| 153 | * Arguments: @unsigned char *k@ = pointer to key buffer |
| 154 | * @size_t bits@ = number of bits to write |
| 155 | * @FILE *fp@ = stream to write on |
| 156 | * |
| 157 | * Returns: --- |
| 158 | * |
| 159 | * Use: Writes bits on a stream. |
| 160 | */ |
| 161 | |
| 162 | static void kgFmt__binary(unsigned char *k, size_t bits, FILE *fp) |
| 163 | { |
| 164 | fwrite(k, 1, bits / 8, fp); |
| 165 | } |
| 166 | |
| 167 | /* --- @kgFmt__base64@ --- * |
| 168 | * |
| 169 | * Arguments: @unsigned char *k@ = pointer to key buffer |
| 170 | * @size_t bits@ = number of bits to write |
| 171 | * @FILE *fp@ = stream to write on |
| 172 | * |
| 173 | * Returns: --- |
| 174 | * |
| 175 | * Use: Writes bits on a stream in an encoded way. |
| 176 | */ |
| 177 | |
| 178 | static void kgFmt__base64(unsigned char *k, size_t bits, FILE *fp) |
| 179 | { |
| 180 | static const char xlt[64] = { "ABCDEFGHIJKLMNOPQRSTUVWXYZ" |
| 181 | "abcdefghijklmnopqrstuvwxyz" |
| 182 | "0123456789+/" }; |
| 183 | unsigned long b; |
| 184 | int ll = 0; |
| 185 | |
| 186 | while (bits > 24) { |
| 187 | b = ((k[0] & 0xffu) << 16) | ((k[1] & 0xffu) << 8) | (k[2] & 0xffu); |
| 188 | k += 3; |
| 189 | bits -= 24; |
| 190 | putc(xlt[(b >> 18) & 0x3fu], fp); |
| 191 | putc(xlt[(b >> 12) & 0x3fu], fp); |
| 192 | putc(xlt[(b >> 6) & 0x3fu], fp); |
| 193 | putc(xlt[(b >> 0) & 0x3fu], fp); |
| 194 | if ((ll += 4) > 70) { |
| 195 | putc('\n', fp); |
| 196 | ll = 0; |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | b = 0; |
| 201 | switch (bits) { |
| 202 | case 24: |
| 203 | b = *k++ & 0xffu; |
| 204 | case 16: |
| 205 | b = (b << 8) | (*k++ & 0xffu); |
| 206 | case 8: |
| 207 | b = (b << 8) | (*k++ & 0xffu); |
| 208 | } |
| 209 | b <<= (24 - bits); |
| 210 | putc(xlt[(b >> 18) & 0x3fu], fp); |
| 211 | putc(xlt[(b >> 12) & 0x3fu], fp); |
| 212 | switch (bits) { |
| 213 | case 24: |
| 214 | putc(xlt[(b >> 6) & 0x3fu], fp); |
| 215 | putc(xlt[(b >> 0) & 0x3fu], fp); |
| 216 | break; |
| 217 | case 16: |
| 218 | putc(xlt[(b >> 6) & 0x3fu], fp); |
| 219 | putc('=', fp); |
| 220 | break; |
| 221 | case 8: |
| 222 | fputs("==", fp); |
| 223 | break; |
| 224 | } |
| 225 | |
| 226 | putc('\n', fp); |
| 227 | } |
| 228 | |
| 229 | /* --- @kg__gen@ --- * |
| 230 | * |
| 231 | * Arguments: @unsigned char *ui@ = pointer to array to fill in |
| 232 | * @size_t sz@ = number of bits to generate |
| 233 | * |
| 234 | * Returns: --- |
| 235 | * |
| 236 | * Use: Uses key timings to generate random numbers. Maybe. |
| 237 | */ |
| 238 | |
| 239 | static void kg__gen(unsigned char *ui, size_t sz) |
| 240 | { |
| 241 | int bits = 32 < sz ? 32 : sz; |
| 242 | size_t wsz = (sz + 31u) & ~31u; |
| 243 | unsigned long last, ldiff = 0; |
| 244 | unsigned long a = 0; |
| 245 | unsigned long fact = 1000000 / CLOCKS_PER_SEC; |
| 246 | |
| 247 | fprintf(kg__ttyfp, |
| 248 | "I need to get %i random bits; I'll do this by timing your keypresses.\n" |
| 249 | "Please type some arbitrary text until I say `done'.\n", |
| 250 | sz); |
| 251 | |
| 252 | { |
| 253 | struct timeval tv; |
| 254 | gettimeofday(&tv, 0); |
| 255 | last = tv.tv_usec / fact + tv.tv_sec * fact; |
| 256 | } |
| 257 | |
| 258 | while (sz) { |
| 259 | int useful; |
| 260 | uint_32 orr, xor; |
| 261 | |
| 262 | /* --- Print current status --- */ |
| 263 | |
| 264 | fprintf(kg__ttyfp, "\r%5i...", sz); |
| 265 | fflush(kg__ttyfp); |
| 266 | |
| 267 | /* --- Read the next character --- */ |
| 268 | |
| 269 | { |
| 270 | char buff[16]; |
| 271 | if (read(kg__tty, buff, sizeof(buff)) < 0) |
| 272 | die("couldn't read from terminal: %s", strerror(errno)); |
| 273 | } |
| 274 | |
| 275 | /* --- Fiddle with times --- * |
| 276 | * |
| 277 | * Read the time now. Turn it into 32 bits of useful information, and |
| 278 | * find the difference between that and the previous time. Compare this |
| 279 | * with the difference between the previous pair of keypresses. |
| 280 | */ |
| 281 | |
| 282 | { |
| 283 | struct timeval tv; |
| 284 | uint_32 n, nd; |
| 285 | |
| 286 | gettimeofday(&tv, 0); |
| 287 | n = tv.tv_usec / fact + tv.tv_sec * fact; |
| 288 | if (!ldiff) { |
| 289 | ldiff = n - last; |
| 290 | last = n; |
| 291 | continue; |
| 292 | } |
| 293 | nd = n - last; |
| 294 | orr = nd | ldiff; |
| 295 | xor = nd ^ ldiff; |
| 296 | D( printf("\nlast = %08lx, next = %08lx, ldiff = %08lx, nd = %08lx\n", |
| 297 | (unsigned long)last, (unsigned long)n, |
| 298 | (unsigned long)ldiff, (unsigned long)nd); |
| 299 | printf("xor = %08lx\n", (unsigned long)xor); ) |
| 300 | ldiff = nd; |
| 301 | last = n; |
| 302 | } |
| 303 | |
| 304 | /* --- Find the useful bits in this value --- * |
| 305 | * |
| 306 | * Find the least significant set bit in @bowl@ and chop it off. Then |
| 307 | * find the most significant set bit and chop that off two. The rest is |
| 308 | * probably interesting. |
| 309 | */ |
| 310 | |
| 311 | { |
| 312 | unsigned long i; |
| 313 | |
| 314 | if (!orr || !xor) |
| 315 | continue; /* erk! */ |
| 316 | |
| 317 | useful = 30; |
| 318 | |
| 319 | i = 0x80000000ul; |
| 320 | if (xor & i) { |
| 321 | while (i && (xor & i) != 0) { |
| 322 | i >>= 1; |
| 323 | useful--; |
| 324 | } |
| 325 | } else { |
| 326 | while (i && (xor & i) == 0) { |
| 327 | i >>= 1; |
| 328 | useful--; |
| 329 | } |
| 330 | } |
| 331 | xor &= ~-i; |
| 332 | |
| 333 | while ((orr & 1) == 0) { |
| 334 | useful--; |
| 335 | orr >>= 1; |
| 336 | xor >>= 1; |
| 337 | } |
| 338 | xor >>= 1; |
| 339 | |
| 340 | if (useful < 1) |
| 341 | continue; |
| 342 | } |
| 343 | |
| 344 | /* --- Now add the bits in the mixing bowl to my stash --- * |
| 345 | * |
| 346 | * There are two cases: |
| 347 | * |
| 348 | * 1. I have more bits than will fit into the accumulator. Then I must |
| 349 | * put as many bits into the accumulator as will fit, store the |
| 350 | * accumulator, and remove the spent bits. |
| 351 | * |
| 352 | * 2. I have too few bits to fit in the accumulator. Then shift them |
| 353 | * in and return. |
| 354 | */ |
| 355 | |
| 356 | while (sz && useful) { |
| 357 | |
| 358 | D( printf("got %i bits, need %i/%i: %8lx\n", |
| 359 | useful, bits, sz, (unsigned long)xor); ) |
| 360 | |
| 361 | if (useful >= bits) { |
| 362 | |
| 363 | D( printf("shifted acc = %08lx\n" |
| 364 | " new bits = %08lx\n" |
| 365 | " result = %08lx\n", |
| 366 | (unsigned long)(a << bits), |
| 367 | (unsigned long)(xor >> (useful - bits)), |
| 368 | (unsigned long)((a << bits) | (xor >> (useful - bits)))); ) |
| 369 | |
| 370 | a = (a << bits) | (xor >> (useful - bits)); |
| 371 | |
| 372 | sz -= bits; |
| 373 | wsz -= bits; |
| 374 | useful -= bits; |
| 375 | |
| 376 | if (sz == 0) { |
| 377 | a <<= wsz; |
| 378 | bits = 32 - wsz; |
| 379 | } else |
| 380 | bits = 32; |
| 381 | |
| 382 | while (bits > 0) { |
| 383 | D( printf("writing %02x\n", (a >> 24) & 0xffu); ) |
| 384 | *ui++ = (a >> 24) & 0xffu; |
| 385 | a <<= 8; |
| 386 | bits -= 8; |
| 387 | } |
| 388 | a = 0; |
| 389 | |
| 390 | bits = 32 < sz ? 32 : sz; |
| 391 | |
| 392 | } else { |
| 393 | |
| 394 | D( printf("shifted acc = %08lx\n" |
| 395 | " new bits = %08lx\n" |
| 396 | " result = %08lx\n", |
| 397 | (unsigned long)(a << useful), |
| 398 | (unsigned long)(xor), |
| 399 | (unsigned long)((a << useful) | (xor))); ) |
| 400 | a = (a << useful) | xor; |
| 401 | bits -= useful; |
| 402 | sz -= useful; |
| 403 | wsz -= useful; |
| 404 | useful = 0; |
| 405 | } |
| 406 | } |
| 407 | } |
| 408 | |
| 409 | fputs("\rDone! \n", kg__ttyfp); |
| 410 | putc('\a', kg__ttyfp); fflush(kg__ttyfp); |
| 411 | sleep(1); |
| 412 | } |
| 413 | |
| 414 | /* --- @main@ --- * |
| 415 | * |
| 416 | * Arguments: @int argc@ = number of arguments |
| 417 | * @char *argv[]@ = array of arguments |
| 418 | * |
| 419 | * Returns: Zero if it worked, nonzero if it didn't. |
| 420 | * |
| 421 | * Use: Generates random numbers from the keyboard. |
| 422 | */ |
| 423 | |
| 424 | int main(int argc, char *argv[]) |
| 425 | { |
| 426 | unsigned char *uip; |
| 427 | size_t sz = 128; |
| 428 | const char *file = 0; |
| 429 | FILE *fp; |
| 430 | |
| 431 | /* --- Formats table --- */ |
| 432 | |
| 433 | static struct { |
| 434 | const char *name; |
| 435 | void (*proc)(unsigned char *k, size_t bits, FILE *fp); |
| 436 | } format[] = { |
| 437 | { "tx", tx_putBits }, |
| 438 | { "hex", tx_putBits }, |
| 439 | { "binary", kgFmt__binary }, |
| 440 | { "base64", kgFmt__base64 }, |
| 441 | { 0, 0 } |
| 442 | }; |
| 443 | |
| 444 | void (*fmt)(unsigned char *, size_t, FILE *) = tx_putBits; |
| 445 | |
| 446 | /* --- Explain who I am --- */ |
| 447 | |
| 448 | ego(argv[0]); |
| 449 | |
| 450 | /* --- Read arguments --- */ |
| 451 | |
| 452 | for (;;) { |
| 453 | static struct option opts[] = { |
| 454 | { "help", 0, 0, 'h' }, |
| 455 | { "bits", gFlag_argReq, 0, 'b' }, |
| 456 | { "output", gFlag_argReq, 0, 'o' }, |
| 457 | { "format", gFlag_argReq, 0, 'f' }, |
| 458 | { 0, 0, 0, 0 } |
| 459 | }; |
| 460 | |
| 461 | int i = mdwopt(argc, argv, "hb:o:f:", opts, 0, 0, 0); |
| 462 | |
| 463 | if (i < 0) |
| 464 | break; |
| 465 | switch (i) { |
| 466 | case 'h': |
| 467 | printf("" |
| 468 | "Usage: %s [--bits=BITS] [--output=FILE] [--format=FORMAT]\n" |
| 469 | "\n" |
| 470 | "Generates BITS (by default, 128) random bits by timing keypresses. The\n" |
| 471 | "resulting number is written to FILE, or standard output in the given\n" |
| 472 | "format. Formats currently supported are:\n" |
| 473 | "\n" |
| 474 | "tx, hex Hexadecimal, with punctuating dashes.\n" |
| 475 | "binary Raw binary.\n" |
| 476 | "base64 Base64-encoded binary; the result is printable ASCII.\n", |
| 477 | quis()); |
| 478 | exit(0); |
| 479 | break; |
| 480 | case 'b': |
| 481 | sz = atoi(optarg); |
| 482 | if (sz == 0) |
| 483 | die("bad number of bits (illegible or zero)"); |
| 484 | if (sz % 8) |
| 485 | die("can only generate a whole number of 8-bit bytes"); |
| 486 | break; |
| 487 | case 'o': |
| 488 | file = optarg; |
| 489 | break; |
| 490 | case 'f': |
| 491 | fmt = 0; |
| 492 | for (i = 0; format[i].name; i++) { |
| 493 | const char *p = format[i].name, *q = optarg; |
| 494 | for (;;) { |
| 495 | if (*q == 0) |
| 496 | break; |
| 497 | if (*p != *q) |
| 498 | break; |
| 499 | p++, q++; |
| 500 | } |
| 501 | if (!*q) { |
| 502 | if (fmt) |
| 503 | die("ambiguous format name: `%s'", optarg); |
| 504 | fmt = format[i].proc; |
| 505 | } |
| 506 | } |
| 507 | if (!fmt) |
| 508 | die("unknown format name: `%s'", optarg); |
| 509 | break; |
| 510 | case '?': |
| 511 | exit(1); |
| 512 | break; |
| 513 | } |
| 514 | } |
| 515 | |
| 516 | if (optind < argc) { |
| 517 | fprintf(stderr, "Usage: %s [--bits=BITS] [--output=FILE]\n", quis()); |
| 518 | exit(1); |
| 519 | } |
| 520 | |
| 521 | /* --- Allocate memory --- */ |
| 522 | |
| 523 | uip = xmalloc(sz / 8); |
| 524 | |
| 525 | /* --- Open the terminal --- * |
| 526 | * |
| 527 | * I'd like to be able to @fprintf@ to the terminal, so use @fopen@. |
| 528 | */ |
| 529 | |
| 530 | if ((kg__ttyfp = fopen("/dev/tty", "r+")) == 0) |
| 531 | die("couldn't open terminal: %s", strerror(errno)); |
| 532 | kg__tty = fileno(kg__ttyfp); |
| 533 | |
| 534 | /* --- Open the output file, if one is specified --- */ |
| 535 | |
| 536 | if (file) { |
| 537 | int fd; |
| 538 | |
| 539 | /* --- Open the file oddly --- * |
| 540 | * |
| 541 | * There's a good reason for this. I want to be able to @fprintf@ (for |
| 542 | * the benefit of @tx_putWords@ mainly) but I also want to ensure that |
| 543 | * only the user has read permissions for the file. So I'll use @open@ |
| 544 | * with an appropriate mode and then @fdopen@ the file descriptor to get |
| 545 | * a stream. Yuk. |
| 546 | */ |
| 547 | |
| 548 | if ((fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0) |
| 549 | die("couldn't open output file: %s", strerror(errno)); |
| 550 | if ((fp = fdopen(fd, "w")) == 0) |
| 551 | die("couldn't attach stream to output file: %s", strerror(errno)); |
| 552 | } else |
| 553 | fp = stdout; |
| 554 | |
| 555 | /* --- Tidy up nicely if I die --- */ |
| 556 | |
| 557 | signal(SIGINT, kg__signal); |
| 558 | signal(SIGTERM, kg__signal); |
| 559 | atexit(kg__crepair); |
| 560 | |
| 561 | /* --- Put the terminal into cbreak, read the key, and restore --- */ |
| 562 | |
| 563 | kg__cbreak(); |
| 564 | kg__gen(uip, sz); |
| 565 | kg__crepair(); |
| 566 | |
| 567 | /* --- Now write the number and exit --- */ |
| 568 | |
| 569 | D( fputs("*** ", fp); tx_putBits(uip, sz, stdout); ) |
| 570 | fmt(uip, sz, fp); |
| 571 | if (file) |
| 572 | fclose(fp); |
| 573 | memset(uip, 0, sz / 8); /* Burn temporary buffer */ |
| 574 | return (0); |
| 575 | } |
| 576 | |
| 577 | /*----- That's all, folks -------------------------------------------------*/ |