mdw@git.distorted.org.uk Git - catacomb/blob - progs/catcrypt.c

   1 /* -*-c-*-
   2  *
   3  * Command-line encryption tool
   4  *
   5  * (c) 2004 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #define _FILE_OFFSET_BITS 64
  31
  32 #include "config.h"
  33
  34 #include <errno.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #include <mLib/base64.h>
  40 #include <mLib/dstr.h>
  41 #include <mLib/mdwopt.h>
  42 #include <mLib/quis.h>
  43 #include <mLib/report.h>
  44 #include <mLib/sub.h>
  45
  46 #include "buf.h"
  47 #include "ct.h"
  48 #include "rand.h"
  49 #include "noise.h"
  50 #include "mprand.h"
  51 #include "key.h"
  52 #include "cc.h"
  53
  54 #include "ectab.h"
  55 #include "ptab.h"
  56
  57 /*----- Static variables --------------------------------------------------*/
  58
  59 static const char *keyring = "keyring";
  60
  61 /*----- Data format -------------------------------------------------------*/
  62
  63 /* --- Overview --- *
  64  *
  65  * The encrypted message is divided into chunks, each preceded by a two-octet
  66  * length.  The chunks don't need to be large -- the idea is that we can
  67  * stream the chunks in and out.
  68  *
  69  * The first chunk is a header.  It contains the decryption key-id, and maybe
  70  * the verification key-id if the message is signed.
  71  *
  72  * Next comes the key-encapsulation chunk.  This is decrypted in some
  73  * KEM-specific way to yield a secret hash.  The hash is expanded using an
  74  * MGF (or similar) to make a symmetric encryption and MAC key.
  75  *
  76  * If the message is signed, there comes a signature chunk.  The signature is
  77  * on the header and key-encapsulation chunks, and further output of the MGF.
  78  * This means that the recipient can modify the message and still have a
  79  * valid signature, so it's not useful for proving things to other people;
  80  * but it also means that the recipient knows that the message is from
  81  * someone who knows the hash, which limits the possiblities to (a) whoever
  82  * encrypted the message (good!) and (b) whoever knows the recipient's
  83  * private key.
  84  *
  85  * Then come message chunks.  Each one begins with a MAC over an implicit
  86  * sequence number and the ciphertext.  The final chunk's ciphertext is
  87  * empty; no other chunk is empty.  Thus can the correct end-of-file be
  88  * discerned.
  89  */
  90
  91 /*----- Chunk I/O ---------------------------------------------------------*/
  92
  93 static void chunk_write(enc *e, buf *b)
  94 {
  95   octet l[2];
  96   size_t n = BLEN(b);
  97   assert(n <= MASK16);
  98   STORE16(l, n);
  99   if (e->ops->write(e, l, 2) ||
 100       e->ops->write(e, BBASE(b), BLEN(b)))
 101     die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 102 }
 103
 104 static void chunk_read(enc *e, dstr *d, buf *b)
 105 {
 106   octet l[2];
 107   size_t n;
 108
 109   dstr_reset(d);
 110   errno = 0;
 111   if (e->ops->read(e, l, 2) != 2)
 112     goto err;
 113   n = LOAD16(l);
 114   dstr_ensure(d, n);
 115   if (e->ops->read(e, d->buf, n) != n)
 116     goto err;
 117   d->len = n;
 118   buf_init(b, d->buf, d->len);
 119   return;
 120
 121 err:
 122   if (!errno) die(EXIT_FAILURE, "unexpected end-of-file on input");
 123   else die(EXIT_FAILURE, "error reading input: %s", strerror(errno));
 124 }
 125
 126 /*----- Encryption --------------------------------------------------------*/
 127
 128 static int encrypt(int argc, char *argv[])
 129 {
 130   const char *fn, *of = 0, *kn = "ccrypt", *skn = 0;
 131   FILE *ofp = 0;
 132   FILE *fp = 0;
 133   const char *ef = "binary";
 134   fprogress ff;
 135   const char *err;
 136   int i;
 137   int en;
 138   size_t n, chsz;
 139   dstr d = DSTR_INIT;
 140   buf b;
 141   size_t seq;
 142   char bb[65536];
 143   unsigned f = 0;
 144   key_file kf;
 145   key *k;
 146   key *sk = 0;
 147   kem *km;
 148   bulk *bc;
 149   sig *s = 0;
 150   const encops *eo;
 151   enc *e;
 152
 153 #define f_bogus 1u
 154 #define f_nocheck 2u
 155 #define f_progress 4u
 156
 157   for (;;) {
 158     static const struct option opt[] = {
 159       { "key",          OPTF_ARGREQ,    0,      'k' },
 160       { "sign-key",     OPTF_ARGREQ,    0,      's' },
 161       { "armour",       0,              0,      'a' },
 162       { "armor",        0,              0,      'a' },
 163       { "format",       OPTF_ARGREQ,    0,      'f' },
 164       { "output",       OPTF_ARGREQ,    0,      'o' },
 165       { "progress",     0,              0,      'p' },
 166       { "nocheck",      0,              0,      'C' },
 167       { 0,              0,              0,      0 }
 168     };
 169     i = mdwopt(argc, argv, "k:s:af:o:pC", opt, 0, 0, 0);
 170     if (i < 0) break;
 171     switch (i) {
 172       case 'k': kn = optarg; break;
 173       case 's': skn = optarg; break;
 174       case 'a': ef = "pem"; break;
 175       case 'f': ef = optarg; break;
 176       case 'o': of = optarg; break;
 177       case 'p': f |= f_progress; break;
 178       case 'C': f |= f_nocheck; break;
 179       default: f |= f_bogus; break;
 180     }
 181   }
 182   if (argc - optind > 1 || (f & f_bogus))
 183     die(EXIT_FAILURE, "Usage: encrypt [-OPTIONS] [FILE]");
 184
 185   if (key_open(&kf, keyring, KOPEN_READ, key_moan, 0))
 186     die(EXIT_FAILURE, "can't open keyring `%s'", keyring);
 187   if ((k = key_bytag(&kf, kn)) == 0)
 188     die(EXIT_FAILURE, "key `%s' not found", kn);
 189   if (skn && (sk = key_bytag(&kf, skn)) == 0)
 190     die(EXIT_FAILURE, "key `%s' not found", skn);
 191
 192   if ((eo = getenc(ef)) == 0)
 193     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 194
 195   fn = optind < argc ? argv[optind++] : "-";
 196   if (strcmp(fn, "-") == 0)
 197     fp = stdin;
 198   else if ((fp = fopen(fn, "rb")) == 0) {
 199     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 200         fn, strerror(errno));
 201   }
 202
 203   if (!of || strcmp(of, "-") == 0)
 204     ofp = stdout;
 205   else if ((ofp = fopen(of, eo->wmode)) == 0) {
 206     die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 207         of, strerror(errno));
 208   }
 209
 210   dstr_reset(&d);
 211   key_fulltag(k, &d);
 212   e = initenc(eo, ofp, "CATCRYPT ENCRYPTED MESSAGE");
 213   km = getkem(k, "cckem", 0, &bc);
 214   if (!(f & f_nocheck) && (err = km->ops->check(km)) != 0)
 215     moan("key %s fails check: %s", d.buf, err);
 216   if (sk) {
 217     dstr_reset(&d);
 218     key_fulltag(sk, &d);
 219     s = getsig(sk, "ccsig", 1);
 220     if ((err = s->ops->check(s)) != 0)
 221       moan("key %s fails check: %s", d.buf, err);
 222   }
 223
 224   /* --- Build the header chunk --- */
 225
 226   dstr_reset(&d);
 227   dstr_ensure(&d, 256);
 228   buf_init(&b, d.buf, 256);
 229   buf_putu32(&b, k->id);
 230   if (sk) buf_putu32(&b, sk->id);
 231   assert(BOK(&b));
 232   if (s) GH_HASHBUF16(s->h, BBASE(&b), BLEN(&b));
 233   chunk_write(e, &b);
 234
 235   /* --- Build the KEM chunk --- */
 236
 237   dstr_reset(&d);
 238   if (setupkem(km, &d, bc)) die(EXIT_FAILURE, "failed to encapsulate key");
 239   buf_init(&b, d.buf, d.len);
 240   BSTEP(&b, d.len);
 241   if (s) GH_HASHBUF16(s->h, BBASE(&b), BLEN(&b));
 242   chunk_write(e, &b);
 243
 244   /* --- Write the signature chunk --- */
 245
 246   if (s) {
 247     GC_ENCRYPT(km->cx, 0, bb, 1024);
 248     GH_HASH(s->h, bb, 1024);
 249     dstr_reset(&d);
 250     if ((en = s->ops->doit(s, &d)) != 0)
 251       die(EXIT_FAILURE, "error creating signature: %s", key_strerror(en));
 252     buf_init(&b, d.buf, d.len);
 253     BSTEP(&b, d.len);
 254     chunk_write(e, &b);
 255   }
 256
 257   /* --- Now do the main crypto --- */
 258
 259   if (f & f_progress) {
 260     if (fprogress_init(&ff, fn, fp)) {
 261       die(EXIT_FAILURE, "failed to initialize progress display: %s",
 262           strerror(errno));
 263     }
 264   }
 265
 266   n = bc->ops->overhead(bc);
 267   dstr_ensure(&d, sizeof(bb) + n);
 268   seq = 0;
 269   chsz = MASK16 - n;
 270   do {
 271     n = fread(bb, 1, chsz, fp);
 272     if (f & f_progress) fprogress_update(&ff, n);
 273     buf_init(&b, d.buf, d.sz);
 274     if ((err = bc->ops->doit(bc, seq, &b, bb, n)) != 0) {
 275       if (f & f_progress) fprogress_done(&ff);
 276       die(EXIT_FAILURE, "failed to encrypt packet: %s\n", err);
 277     }
 278     seq++;
 279     chunk_write(e, &b);
 280   } while (n);
 281
 282   /* --- All done --- */
 283
 284   if (f & f_progress) fprogress_done(&ff);
 285   e->ops->encdone(e);
 286   bc->ops->destroy(bc);
 287   freeenc(e);
 288   if (s) freesig(s);
 289   freekem(km);
 290   if (fp != stdin) fclose(fp);
 291   if (of) fclose(ofp);
 292   key_close(&kf);
 293   dstr_destroy(&d);
 294   return (0);
 295
 296 #undef f_bogus
 297 #undef f_nocheck
 298 #undef f_progress
 299 }
 300
 301 /*---- Decryption ---------------------------------------------------------*/
 302
 303 static int decrypt(int argc, char *argv[])
 304 {
 305   const char *fn, *of = 0;
 306   FILE *ofp = 0, *rfp = 0;
 307   FILE *fp = 0;
 308   const char *ef = "binary";
 309   fprogress ff;
 310   int i;
 311   size_t n;
 312   dstr d = DSTR_INIT;
 313   char bb[65536];
 314   buf b;
 315   key_file kf;
 316   size_t seq;
 317   uint32 id;
 318   key *k;
 319   key *sk = 0;
 320   kem *km;
 321   sig *s = 0;
 322   bulk *bc;
 323   unsigned f = 0;
 324   const encops *eo;
 325   const char *err;
 326   int verb = 1;
 327   enc *e;
 328
 329 #define f_bogus 1u
 330 #define f_buffer 2u
 331 #define f_nocheck 4u
 332 #define f_progress 8u
 333
 334   for (;;) {
 335     static const struct option opt[] = {
 336       { "armour",       0,              0,      'a' },
 337       { "armor",        0,              0,      'a' },
 338       { "buffer",       0,              0,      'b' },
 339       { "verbose",      0,              0,      'v' },
 340       { "quiet",        0,              0,      'q' },
 341       { "nocheck",      0,              0,      'C' },
 342       { "format",       OPTF_ARGREQ,    0,      'f' },
 343       { "output",       OPTF_ARGREQ,    0,      'o' },
 344       { "progress",     0,              0,      'p' },
 345       { 0,              0,              0,      0 }
 346     };
 347     i = mdwopt(argc, argv, "abf:o:pqvC", opt, 0, 0, 0);
 348     if (i < 0) break;
 349     switch (i) {
 350       case 'a': ef = "pem"; break;
 351       case 'b': f |= f_buffer; break;
 352       case 'v': verb++; break;
 353       case 'q': if (verb) verb--; break;
 354       case 'C': f |= f_nocheck; break;
 355       case 'f': ef = optarg; break;
 356       case 'o': of = optarg; break;
 357       case 'p': f |= f_progress; break;
 358       default: f |= f_bogus; break;
 359     }
 360   }
 361   if (argc - optind > 1 || (f & f_bogus))
 362     die(EXIT_FAILURE, "Usage: decrypt [-OPTIONS] [FILE]");
 363
 364   if ((eo = getenc(ef)) == 0)
 365     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 366
 367   fn = optind < argc ? argv[optind++] : "-";
 368   if (strcmp(fn, "-") == 0)
 369     fp = stdin;
 370   else if ((fp = fopen(fn, eo->rmode)) == 0) {
 371     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 372         fn, strerror(errno));
 373   }
 374
 375   if (key_open(&kf, keyring, KOPEN_READ, key_moan, 0))
 376     die(EXIT_FAILURE, "can't open keyring `%s'", keyring);
 377
 378   e = initdec(eo, fp, checkbdry, "CATCRYPT ENCRYPTED MESSAGE");
 379
 380   if (f & f_progress) {
 381     if (fprogress_init(&ff, fn, fp)) {
 382       die(EXIT_FAILURE, "failed to initialize progress display: %s",
 383           strerror(errno));
 384     }
 385   }
 386
 387   /* --- Read the header chunk --- */
 388
 389   chunk_read(e, &d, &b);
 390   if (f & f_progress)
 391     fprogress_update(&ff, BLEFT(&b)*e->ops->ncook/e->ops->nraw);
 392   if (buf_getu32(&b, &id)) {
 393     if (f & f_progress) fprogress_done(&ff);
 394     if (verb) printf("FAIL malformed header: missing keyid\n");
 395     exit(EXIT_FAILURE);
 396   }
 397   if ((k = key_byid(&kf, id)) == 0) {
 398     if (f & f_progress) fprogress_done(&ff);
 399     if (verb) printf("FAIL key id %08lx not found\n", (unsigned long)id);
 400     exit(EXIT_FAILURE);
 401   }
 402   if (BLEFT(&b)) {
 403     if (buf_getu32(&b, &id)) {
 404       if (f & f_progress) fprogress_done(&ff);
 405       if (verb) printf("FAIL malformed header: missing signature keyid\n");
 406       exit(EXIT_FAILURE);
 407     }
 408     if ((sk = key_byid(&kf, id)) == 0) {
 409       if (f & f_progress) fprogress_done(&ff);
 410       if (verb) printf("FAIL key id %08lx not found\n", (unsigned long)id);
 411       exit(EXIT_FAILURE);
 412     }
 413   }
 414   if (BLEFT(&b)) {
 415     if (f & f_progress) fprogress_done(&ff);
 416     if (verb) printf("FAIL malformed header: junk at end\n");
 417     exit(EXIT_FAILURE);
 418   }
 419   if (sk) {
 420     s = getsig(sk, "ccsig", 0);
 421     if (!(f & f_nocheck) && verb && (err = s->ops->check(s)) != 0) {
 422       dstr_reset(&d);
 423       key_fulltag(sk, &d);
 424       printf("WARN verification key %s fails check: %s\n", d.buf, err);
 425     }
 426     GH_HASHBUF16(s->h, BBASE(&b), BSZ(&b));
 427   }
 428
 429   /* --- Find the key --- */
 430
 431   km = getkem(k, "cckem", 1, &bc);
 432
 433   /* --- Read the KEM chunk --- */
 434
 435   chunk_read(e, &d, &b);
 436   if (f & f_progress)
 437     fprogress_update(&ff, BLEFT(&b)*e->ops->ncook/e->ops->nraw);
 438   if (setupkem(km, &d, bc)) {
 439     if (f & f_progress) fprogress_done(&ff);
 440     if (verb) printf("FAIL failed to decapsulate key\n");
 441     exit(EXIT_FAILURE);
 442   }
 443   if (s) GH_HASHBUF16(s->h, d.buf, d.len);
 444
 445   /* --- Verify the signature, if there is one --- */
 446
 447   if (sk) {
 448     dstr_reset(&d);
 449     dstr_ensure(&d, 1024);
 450     GC_ENCRYPT(km->cx, 0, d.buf, 1024);
 451     GH_HASH(s->h, d.buf, 1024);
 452     chunk_read(e, &d, &b);
 453     if (f & f_progress)
 454       fprogress_update(&ff, BLEFT(&b)*e->ops->ncook/e->ops->nraw);
 455     if (s->ops->doit(s, &d)) {
 456       if (f & f_progress) fprogress_done(&ff);
 457       if (verb) printf("FAIL signature verification failed\n");
 458       exit(EXIT_FAILURE);
 459     }
 460     if (verb) {
 461       dstr_reset(&d);
 462       key_fulltag(sk, &d);
 463       if (f & f_progress) fprogress_clear(&ff);
 464       printf("INFO good-signature %s\n", d.buf);
 465     }
 466     freesig(s);
 467   } else if (verb) {
 468     if (f & f_progress) fprogress_clear(&ff);
 469     printf("INFO no-signature\n");
 470   }
 471
 472   /* --- Now decrypt the main body --- */
 473
 474   if (!of || strcmp(of, "-") == 0) {
 475     ofp = stdout;
 476     f |= f_buffer;
 477   }
 478   if (!(f & f_buffer)) {
 479     if ((ofp = fopen(of, "wb")) == 0) {
 480       if (f & f_progress) fprogress_done(&ff);
 481       die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 482           of, strerror(errno));
 483     }
 484     rfp = ofp;
 485   } else if ((rfp = tmpfile()) == 0) {
 486     if (f & f_progress) fprogress_done(&ff);
 487     die(EXIT_FAILURE, "couldn't create temporary file: %s", strerror(errno));
 488   }
 489
 490   seq = 0;
 491   dstr_ensure(&d, bc->ops->overhead(bc));
 492   dstr_ensure(&d, 4);
 493   for (;;) {
 494     chunk_read(e, &d, &b);
 495     if (f & f_progress)
 496       fprogress_update(&ff, BLEFT(&b)*e->ops->ncook/e->ops->nraw);
 497     buf_init(&b, bb, sizeof(bb));
 498     if ((err = bc->ops->doit(bc, seq, &b, d.buf, d.len)) != 0) {
 499       if (f & f_progress) fprogress_done(&ff);
 500       if (verb) printf("FAIL bad ciphertext chunk: %s\n", err);
 501       exit(EXIT_FAILURE);
 502     }
 503     seq++;
 504     if (!BLEN(&b)) break;
 505     if (fwrite(BBASE(&b), 1, BLEN(&b), rfp) != BLEN(&b)) {
 506       if (f & f_progress) fprogress_done(&ff);
 507       if (verb) printf("FAIL error writing output: %s\n", strerror(errno));
 508       exit(EXIT_FAILURE);
 509     }
 510   }
 511
 512   if (f & f_progress) fprogress_done(&ff);
 513   if (fflush(rfp) || ferror(rfp)) {
 514     if (verb) printf("FAIL error writing output: %s\n", strerror(errno));
 515     exit(EXIT_FAILURE);
 516   }
 517   if (f & f_buffer) {
 518     if (!ofp && (ofp = fopen(of, "wb")) == 0) {
 519       die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 520           of, strerror(errno));
 521     }
 522     rewind(rfp);
 523     if (f & f_progress) fprogress_init(&ff, "copying buffer", rfp);
 524     dstr_reset(&d);
 525     dstr_ensure(&d, 65536);
 526     if (verb && ofp == stdout) printf("DATA\n");
 527     for (;;) {
 528       n = fread(d.buf, 1, d.sz, rfp);
 529       if (!n) break;
 530       if (f & f_progress) fprogress_update(&ff, n);
 531       if (fwrite(d.buf, 1, n, ofp) < n) {
 532         if (f & f_progress) fprogress_done(&ff);
 533         die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 534       }
 535     }
 536     if (f & f_progress) fprogress_done(&ff);
 537     if (ferror(rfp) || fclose(rfp))
 538       die(EXIT_FAILURE, "error unbuffering output: %s", strerror(errno));
 539   }
 540
 541   e->ops->decdone(e);
 542   if (verb && ofp != stdout)
 543     printf("OK decrypted successfully\n");
 544   if (ofp && (fflush(ofp) || ferror(ofp) || fclose(ofp)))
 545       die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 546   bc->ops->destroy(bc);
 547   freeenc(e);
 548   freekem(km);
 549   if (fp != stdin) fclose(fp);
 550   key_close(&kf);
 551   dstr_destroy(&d);
 552   return (0);
 553
 554 #undef f_bogus
 555 #undef f_buffer
 556 #undef f_nocheck
 557 #undef f_progress
 558 }
 559
 560 /*----- Main code ---------------------------------------------------------*/
 561
 562 #define LISTS(LI)                                                       \
 563   LI("Lists", list,                                                     \
 564      listtab[i].name, listtab[i].name)                                  \
 565   LI("Key-encapsulation mechanisms", kem,                               \
 566      kemtab[i].name, kemtab[i].name)                                    \
 567   LI("Bulk crypto transforms", bulk,                                    \
 568      bulktab[i].name, bulktab[i].name)                                  \
 569   LI("Signature schemes", sig,                                          \
 570      sigtab[i].name, sigtab[i].name)                                    \
 571   LI("Encodings", enc,                                                  \
 572      enctab[i].name, enctab[i].name)                                    \
 573   LI("Symmetric encryption algorithms", cipher,                         \
 574      gciphertab[i], gciphertab[i]->name)                                \
 575   LI("Hash functions", hash,                                            \
 576      ghashtab[i], ghashtab[i]->name)                                    \
 577   LI("Message authentication codes", mac,                               \
 578      gmactab[i], gmactab[i]->name)
 579
 580 MAKELISTTAB(listtab, LISTS)
 581
 582 int cmd_show(int argc, char *argv[])
 583 {
 584   return (displaylists(listtab, argv + 1));
 585 }
 586
 587 static int cmd_help(int, char **);
 588
 589 static cmd cmdtab[] = {
 590   { "help", cmd_help, "help [COMMAND...]" },
 591   { "show", cmd_show, "show [ITEM...]" },
 592   CMD_ENCODE,
 593   CMD_DECODE,
 594   { "encrypt", encrypt,
 595     "encrypt [-apC] [-k TAG] [-s TAG] [-f FORMAT]\n\t\
 596 [-o OUTPUT] [FILE]", "\
 597 Options:\n\
 598 \n\
 599 -a, --armour            Same as `-f pem'.\n\
 600 -f, --format=FORMAT     Encode as FORMAT.\n\
 601 -k, --key=TAG           Use public encryption key named by TAG.\n\
 602 -s, --sign-key=TAG      Use private signature key named by TAG.\n\
 603 -o, --output=FILE       Write output to FILE.\n\
 604 -p, --progress          Show progress on large files.\n\
 605 -C, --nocheck           Don't check the public key.\n\
 606 " },
 607   { "decrypt", decrypt,
 608     "decrypt [-abpqvC] [-f FORMAT] [-o OUTPUT] [FILE]", "\
 609 Options:\n\
 610 \n\
 611 -a, --armour            Same as `-f pem'.\n\
 612 -b, --buffer            Buffer output until we're sure we have it all.\n\
 613 -f, --format=FORMAT     Decode as FORMAT.\n\
 614 -o, --output=FILE       Write output to FILE.\n\
 615 -p, --progress          Show progress on large files.\n\
 616 -q, --quiet             Produce fewer messages.\n\
 617 -v, --verbose           Produce more verbose messages.\n\
 618 -C, --nocheck           Don't check the private key.\n\
 619 " },
 620   { 0, 0, 0 }
 621 };
 622
 623 static int cmd_help(int argc, char **argv)
 624 {
 625   sc_help(cmdtab, stdout, argv + 1);
 626   return (0);
 627 }
 628
 629 void version(FILE *fp)
 630 {
 631   pquis(fp, "$, Catacomb version " VERSION "\n");
 632 }
 633
 634 static void usage(FILE *fp)
 635 {
 636   pquis(fp, "Usage: $ [-k KEYRING] COMMAND [ARGS]\n");
 637 }
 638
 639 void help_global(FILE *fp)
 640 {
 641   usage(fp);
 642   fputs("\n\
 643 Encrypt and decrypt files.\n\
 644 \n\
 645 Global command-line options:\n\
 646 \n\
 647 -h, --help [COMMAND...] Show this help message, or help for COMMANDs.\n\
 648 -v, --version           Show program version number.\n\
 649 -u, --usage             Show a terse usage message.\n\
 650 \n\
 651 -k, --keyring=FILE      Read keys from FILE.\n",
 652         fp);
 653 }
 654
 655 /* --- @main@ --- *
 656  *
 657  * Arguments:   @int argc@ = number of command line arguments
 658  *              @char *argv[]@ = vector of command line arguments
 659  *
 660  * Returns:     Zero if successful, nonzero otherwise.
 661  *
 662  * Use:         Encrypts or decrypts files.
 663  */
 664
 665 int main(int argc, char *argv[])
 666 {
 667   unsigned f = 0;
 668
 669 #define f_bogus 1u
 670
 671   /* --- Initialize the library --- */
 672
 673   ego(argv[0]);
 674   sub_init();
 675   rand_noisesrc(RAND_GLOBAL, &noise_source);
 676   rand_seed(RAND_GLOBAL, 160);
 677
 678   /* --- Parse options --- */
 679
 680   for (;;) {
 681     static struct option opts[] = {
 682       { "help",         0,              0,      'h' },
 683       { "version",      0,              0,      'v' },
 684       { "usage",        0,              0,      'u' },
 685       { "keyring",      OPTF_ARGREQ,    0,      'k' },
 686       { 0,              0,              0,      0 }
 687     };
 688     int i = mdwopt(argc, argv, "+hvu k:", opts, 0, 0, 0);
 689     if (i < 0)
 690       break;
 691     switch (i) {
 692       case 'h':
 693         sc_help(cmdtab, stdout, argv + optind);
 694         exit(0);
 695         break;
 696       case 'v':
 697         version(stdout);
 698         exit(0);
 699         break;
 700       case 'u':
 701         usage(stdout);
 702         exit(0);
 703       case 'k':
 704         keyring = optarg;
 705         break;
 706       default:
 707         f |= f_bogus;
 708         break;
 709     }
 710   }
 711
 712   argc -= optind;
 713   argv += optind;
 714   optind = 0;
 715   if (f & f_bogus || argc < 1) {
 716     usage(stderr);
 717     exit(EXIT_FAILURE);
 718   }
 719
 720   /* --- Dispatch to the correct subcommand handler --- */
 721
 722   return (findcmd(cmdtab, argv[0])->cmd(argc, argv));
 723
 724 #undef f_bogus
 725 }
 726
 727 /*----- That's all, folks -------------------------------------------------*/