git.distorted.org.uk Git - u/mdw/catacomb/blob - cc-enc.c

   1 /* -*-c-*-
   2  *
   3  * $Id$
   4  *
   5  * Catcrypt data encoding
   6  *
   7  * (c) 2004 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb 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 Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Header files ------------------------------------------------------*/
  31
  32 #include <errno.h>
  33 #include <stdio.h>
  34
  35 #include <mLib/alloc.h>
  36 #include <mLib/base64.h>
  37 #include <mLib/dstr.h>
  38 #include <mLib/mdwopt.h>
  39 #include <mLib/report.h>
  40 #include <mLib/sub.h>
  41
  42 #include "cc.h"
  43
  44 typedef int encbdryp(const char *, void *);
  45
  46 /*----- Main code ---------------------------------------------------------*/
  47
  48 /* --- Binary --- */
  49
  50 static enc *bin_encinit(FILE *fp, const char *msg)
  51   { enc *e = CREATE(enc); return (e); }
  52 static enc *bin_decinit(FILE *fp, encbdryp *func, void *p)
  53   { enc *e = CREATE(enc); return (e); }
  54
  55 static int bin_read(enc *e, void *p, size_t sz)
  56 {
  57   size_t n;
  58
  59   if (!sz) return (0);
  60   n = fread(p, 1, sz, e->fp);
  61   if (!n || ferror(e->fp)) return (-1);
  62   return (n);
  63 }
  64
  65 static int bin_write(enc *e, const void *p, size_t sz)
  66   { if (sz && fwrite(p, 1, sz, e->fp) < sz) return (-1); return (0); }
  67
  68 static int bin_done(enc *e) { return (0); }
  69
  70 static void bin_destroy(enc *e) { DESTROY(e); }
  71
  72 /* --- PEM --- */
  73
  74 typedef struct pem_encctx {
  75   enc e;
  76   char *msg;
  77   unsigned f;
  78   base64_ctx b;
  79   dstr d;
  80   size_t n;
  81 #define PEMF_NL 1u
  82 #define PEMF_EOF 2u
  83 } pem_encctx;
  84
  85 static enc *pem_encinit(FILE *fp, const char *msg)
  86 {
  87   pem_encctx *pe = CREATE(pem_encctx);
  88   base64_init(&pe->b);
  89   fprintf(fp, "-----BEGIN %s-----\n", msg);
  90   pe->msg = xstrdup(msg);
  91   dstr_create(&pe->d);
  92   pe->n = 0;
  93   pe->f = 0;
  94   return (&pe->e);
  95 }
  96
  97 int checkbdry(const char *b, void *p) { return (!p || strcmp(b, p) == 0); }
  98
  99 static enc *pem_decinit(FILE *fp, encbdryp *func, void *p)
 100 {
 101   char buf[128];
 102   int i, d;
 103   pem_encctx *pe;
 104   int ch;
 105
 106   /* --- Go until I find a newline and `-----' --- */
 107
 108 top:
 109   d = 0;
 110   for (;;) {
 111     if ((ch = getc(fp)) == EOF) goto fail;
 112     switch (ch) {
 113       case '\n': d = 0; break;
 114       case '-': if (d >= 0) { d++; if (d == 5) goto banner; }; break;
 115       default: d = -1; break;
 116     }
 117   }
 118
 119   /* --- See what the banner looks like --- */
 120
 121 banner:
 122   i = d = 0;
 123   for (;;) {
 124     if ((ch = getc(fp)) == EOF) goto fail;
 125     if (ch == '-') { d++; continue; }
 126     if (ch == '\n') break;
 127     if (i + d + 1 >= sizeof(buf)) goto top;
 128     while (d) { buf[i++] = '-'; d--; }
 129     buf[i++] = ch;
 130   }
 131   buf[i] = 0;
 132
 133   /* --- Check we have the right framing --- */
 134
 135   if (d != 5) goto top;
 136   if (strncmp(buf, "BEGIN ", 6) != 0 || (func && !func(buf + 6, p)))
 137     goto top;
 138
 139   /* --- Ready --- */
 140
 141   pe = CREATE(pem_encctx);
 142   base64_init(&pe->b);
 143   pe->msg = xstrdup(buf + 6);
 144   dstr_create(&pe->d);
 145   pe->n = 0;
 146   pe->f = PEMF_NL;
 147   return (&pe->e);
 148
 149   /* --- Failed --- */
 150
 151 fail:
 152   die(EXIT_FAILURE, "initial encapsulation boundary not found");
 153   return (0);
 154 }
 155
 156 #define PEM_CHUNKSZ 4096
 157
 158 static int pem_read(enc *e, void *p, size_t sz)
 159 {
 160   pem_encctx *pe = (pem_encctx *)e;
 161   char buf[PEM_CHUNKSZ];
 162   char *pp = p;
 163   int ch;
 164   size_t n;
 165   int rc = 0;
 166
 167   for (;;) {
 168     n = pe->d.len - pe->n;
 169     if (n > sz) n = sz;
 170     memcpy(pp, pe->d.buf + pe->n, n);
 171     pe->n += n;
 172     pp += n;
 173     rc += n;
 174     sz -= n;
 175     if (!sz) break;
 176     if (pe->f & PEMF_EOF) return (rc ? rc : -1);
 177     dstr_reset(&pe->d);
 178     n = 0;
 179     for (;;) {
 180       if ((ch = getc(pe->e.fp)) == EOF) return (-1);
 181       if ((pe->f & PEMF_NL) && ch == '-') {
 182         ungetc(ch, pe->e.fp);
 183         pe->f |= PEMF_EOF;
 184         break;
 185       }
 186       if (ch == '\n') { pe->f |= PEMF_NL; continue; }
 187       pe->f &= ~PEMF_NL;
 188       buf[n++] = ch;
 189       if (n >= PEM_CHUNKSZ) break;
 190     }
 191     if (n)
 192       base64_decode(&pe->b, buf, n, &pe->d);
 193     if (pe->f & PEMF_EOF)
 194       base64_decode(&pe->b, 0, 0, &pe->d);
 195     pe->n = 0;
 196   }
 197   return (rc);
 198 }
 199
 200 static int pem_write(enc *e, const void *p, size_t sz)
 201 {
 202   pem_encctx *pe = (pem_encctx *)e;
 203   const char *pp = p;
 204   size_t n;
 205
 206   while (sz) {
 207     n = PEM_CHUNKSZ;
 208     if (n > sz) n = sz;
 209     dstr_reset(&pe->d);
 210     base64_encode(&pe->b, pp, n, &pe->d);
 211     if (fwrite(pe->d.buf, 1, pe->d.len, pe->e.fp) < pe->d.len)
 212       return (-1);
 213     pp += n;
 214     sz -= n;
 215   }
 216   return (0);
 217 }
 218
 219 static int pem_encdone(enc *e)
 220 {
 221   pem_encctx *pe = (pem_encctx *)e;
 222   dstr_reset(&pe->d);
 223   base64_encode(&pe->b, 0, 0, &pe->d);
 224   if (fwrite(pe->d.buf, 1, pe->d.len, pe->e.fp) < pe->d.len)
 225     return (-1);
 226   if (pe->b.lnlen) fputc('\n', pe->e.fp);
 227   fprintf(pe->e.fp, "-----END %s-----\n", pe->msg);
 228   return (0);
 229 }
 230
 231 static int pem_decdone(enc *e)
 232 {
 233   pem_encctx *pe = (pem_encctx *)e;
 234   char buf[128];
 235   int i, d;
 236   int ch;
 237
 238   for (d = 0; d < 5; d++)
 239     if ((ch = getc(pe->e.fp)) != '-') goto fail;
 240   i = d = 0;
 241   for (;;) {
 242     if ((ch = getc(pe->e.fp)) == EOF) goto fail;
 243     if (ch == '-') { d++; continue; }
 244     if (ch == '\n') break;
 245     if (i + d + 1 >= sizeof(buf)) goto fail;
 246     while (d) { buf[i++] = '-'; d--; }
 247     buf[i++] = ch;
 248   }
 249   if (d != 5) goto fail;
 250   buf[i] = 0;
 251   if (strncmp(buf, "END ", 4) != 0 || strcmp(buf + 4, pe->msg) != 0)
 252     goto fail;
 253   return (0);
 254
 255 fail:
 256   die(EXIT_FAILURE, "final encapsulation boundary not found");
 257   return (-1);
 258 }
 259
 260 static void pem_destroy(enc *e)
 261 {
 262   pem_encctx *pe = (pem_encctx *)e;
 263   dstr_destroy(&pe->d);
 264   xfree(pe->msg);
 265   DESTROY(pe);
 266 }
 267
 268 /* --- Encoder table --- */
 269
 270 const encops enctab[] = {
 271   { "binary", "rb", "wb",
 272     bin_encinit, bin_decinit,
 273     bin_read, bin_write,
 274     bin_done, bin_done,
 275     bin_destroy },
 276   { "pem", "r", "w",
 277     pem_encinit, pem_decinit,
 278     pem_read, pem_write,
 279     pem_encdone, pem_decdone,
 280     pem_destroy },
 281   { 0 }
 282 };
 283
 284 /* --- @getenc@ --- *
 285  *
 286  * Arguments:   @const char *enc@ = name of wanted encoding
 287  *
 288  * Returns:     Pointer to encoder operations.
 289  *
 290  * Use:         Finds a named encoder or decoder.
 291  */
 292
 293 const encops *getenc(const char *enc)
 294 {
 295   const encops *eo;
 296
 297   for (eo = enctab; eo->name; eo++) {
 298     if (strcmp(eo->name, enc) == 0)
 299       goto e_found;
 300   }
 301   die(EXIT_FAILURE, "couldn't find encoding `%s'", enc);
 302 e_found:
 303   return (eo);
 304 }
 305
 306 /* --- @initenc@ --- *
 307  *
 308  * Arguments:   @const encops *eo@ = operations (from @getenc@)
 309  *              @FILE *fp@ = file handle to attach
 310  *              @const char *msg@ = banner message
 311  *
 312  * Returns:     The encoder object.
 313  *
 314  * Use:         Initializes an encoder.
 315  */
 316
 317 enc *initenc(const encops *eo, FILE *fp, const char *msg)
 318 {
 319   enc *e = eo->initenc(fp, msg);
 320   e->ops = eo;
 321   e->fp = fp;
 322   return (e);
 323 }
 324
 325 /* --- @initdec@ --- *
 326  *
 327  * Arguments:   @const encops *eo@ = operations (from @getenc@)
 328  *              @FILE *fp@ = file handle to attach
 329  *              @int (*func)(const char *, void *)@ = banner check function
 330  *              @void *p@ = argument for @func@
 331  *
 332  * Returns:     The encoder object.
 333  *
 334  * Use:         Initializes an encoder.
 335  */
 336
 337 enc *initdec(const encops *eo, FILE *fp,
 338              int (*func)(const char *, void *), void *p)
 339 {
 340   enc *e = eo->initdec(fp, func, p);
 341   e->ops = eo;
 342   e->fp = fp;
 343   return (e);
 344 }
 345
 346 /* --- @freeenc@ --- *
 347  *
 348  * Arguments:   @enc *e@ = encoder object
 349  *
 350  * Returns:     ---
 351  *
 352  * Use:         Frees an encoder object.
 353  */
 354
 355 void freeenc(enc *e) { e->ops->destroy(e); }
 356
 357 /*----- Encoding and decoding commands ------------------------------------*/
 358
 359 int cmd_encode(int argc, char *argv[])
 360 {
 361   const char *of = 0;
 362   FILE *ofp = 0;
 363   FILE *fp = 0;
 364   const char *ef = "binary";
 365   const char *bd = "MESSAGE";
 366   int i;
 367   size_t n;
 368   char buf[4096];
 369   unsigned f = 0;
 370   const encops *eo;
 371   enc *e;
 372
 373 #define f_bogus 1u
 374
 375   for (;;) {
 376     static const struct option opt[] = {
 377       { "format",       OPTF_ARGREQ,    0,      'f' },
 378       { "boundary",     OPTF_ARGREQ,    0,      'b' },
 379       { "output",       OPTF_ARGREQ,    0,      'o' },
 380       { 0,              0,              0,      0 }
 381     };
 382     i = mdwopt(argc, argv, "f:b:o:", opt, 0, 0, 0);
 383     if (i < 0) break;
 384     switch (i) {
 385       case 'f': ef = optarg; break;
 386       case 'b': bd = optarg; break;
 387       case 'o': of = optarg; break;
 388       default: f |= f_bogus; break;
 389     }
 390   }
 391   if (argc - optind > 1 || (f & f_bogus))
 392     die(EXIT_FAILURE, "Usage: encode [-OPTIONS] [FILE]");
 393
 394   if ((eo = getenc(ef)) == 0)
 395     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 396
 397   if (optind == argc)
 398     fp = stdin;
 399   else if (strcmp(argv[optind], "-") == 0) {
 400     fp = stdin;
 401     optind++;
 402   } else if ((fp = fopen(argv[optind], "rb")) == 0) {
 403     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 404         argv[optind], strerror(errno));
 405   } else
 406     optind++;
 407
 408   if (!of || strcmp(of, "-") == 0)
 409     ofp = stdout;
 410   else if ((ofp = fopen(of, eo->wmode)) == 0) {
 411     die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 412         ofp, strerror(errno));
 413   }
 414
 415   e = initenc(eo, ofp, bd);
 416
 417   do {
 418     n = fread(buf, 1, sizeof(buf), fp);
 419     if (e->ops->write(e, buf, n))
 420       die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 421   } while (n == sizeof(buf));
 422   e->ops->encdone(e);
 423   freeenc(e);
 424   return (0);
 425
 426 #undef f_bogus
 427 }
 428
 429 int cmd_decode(int argc, char *argv[])
 430 {
 431   const char *of = 0;
 432   FILE *ofp = 0;
 433   FILE *fp = 0;
 434   const char *ef = "binary";
 435   const char *bd = 0;
 436   int i;
 437   char buf[4096];
 438   unsigned f = 0;
 439   const encops *eo;
 440   enc *e;
 441
 442 #define f_bogus 1u
 443
 444   for (;;) {
 445     static const struct option opt[] = {
 446       { "format",       OPTF_ARGREQ,    0,      'f' },
 447       { "boundary",     OPTF_ARGREQ,    0,      'b' },
 448       { "output",       OPTF_ARGREQ,    0,      'o' },
 449       { 0,              0,              0,      0 }
 450     };
 451     i = mdwopt(argc, argv, "f:b:o:", opt, 0, 0, 0);
 452     if (i < 0) break;
 453     switch (i) {
 454       case 'f': ef = optarg; break;
 455       case 'b': bd = optarg; break;
 456       case 'o': of = optarg; break;
 457       default: f |= f_bogus; break;
 458     }
 459   }
 460   if (argc - optind > 1 || (f & f_bogus))
 461     die(EXIT_FAILURE, "Usage: decode [-OPTIONS] [FILE]");
 462
 463   if ((eo = getenc(ef)) == 0)
 464     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 465
 466   if (optind == argc)
 467     fp = stdin;
 468   else if (strcmp(argv[optind], "-") == 0) {
 469     fp = stdin;
 470     optind++;
 471   } else if ((fp = fopen(argv[optind], eo->rmode)) == 0) {
 472     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 473         argv[optind], strerror(errno));
 474   } else
 475     optind++;
 476
 477   if (!of || strcmp(of, "-") == 0)
 478     ofp = stdout;
 479   else if ((ofp = fopen(of, "wb")) == 0) {
 480     die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 481         ofp, strerror(errno));
 482   }
 483
 484   e = initdec(eo, fp, checkbdry, (/*unconst*/ void *)bd);
 485
 486   do {
 487     if ((i = e->ops->read(e, buf, sizeof(buf))) < 0)
 488       die(EXIT_FAILURE, "error reading input: %s", strerror(errno));
 489     if (fwrite(buf, 1, i, ofp) < i)
 490       die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 491   } while (i == sizeof(buf));
 492   e->ops->decdone(e);
 493   freeenc(e);
 494   return (0);
 495
 496 #undef f_bogus
 497 }
 498
 499 /*----- That's all, folks -------------------------------------------------*/