usr.bin/uudecode/uudecode.c

   1 /*-
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #if 0
  35 #ifndef lint
  36 static const char copyright[] =
  37 "@(#) Copyright (c) 1983, 1993\n\
  38         The Regents of the University of California.  All rights reserved.\n";
  39 #endif /* not lint */
  40
  41 #ifndef lint
  42 static char sccsid[] = "@(#)uudecode.c  8.2 (Berkeley) 4/2/94";
  43 #endif /* not lint */
  44 #endif
  45 #include <sys/cdefs.h>
  46 __FBSDID("$FreeBSD$");
  47
  48 /*
  49  * uudecode [file ...]
  50  *
  51  * create the specified file, decoding as you go.
  52  * used with uuencode.
  53  */
  54 #include <sys/param.h>
  55 #include <sys/socket.h>
  56 #include <sys/stat.h>
  57
  58 #include <netinet/in.h>
  59
  60 #include <ctype.h>
  61 #include <err.h>
  62 #include <errno.h>
  63 #include <fcntl.h>
  64 #include <libgen.h>
  65 #include <pwd.h>
  66 #include <resolv.h>
  67 #include <stdio.h>
  68 #include <stdlib.h>
  69 #include <string.h>
  70 #include <unistd.h>
  71
  72 static const char *infile, *outfile;
  73 static FILE *infp, *outfp;
  74 static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
  75
  76 static void     usage(void);
  77 static int      decode(void);
  78 static int      decode2(void);
  79 static int      uu_decode(void);
  80 static int      base64_decode(void);
  81
  82 int
  83 main(int argc, char *argv[])
  84 {
  85         int rval, ch;
  86
  87         if (strcmp(basename(argv[0]), "b64decode") == 0)
  88                 base64 = 1;
  89
  90         while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
  91                 switch (ch) {
  92                 case 'c':
  93                         if (oflag || rflag)
  94                                 usage();
  95                         cflag = 1; /* multiple uudecode'd files */
  96                         break;
  97                 case 'i':
  98                         iflag = 1; /* ask before override files */
  99                         break;
 100                 case 'm':
 101                         base64 = 1;
 102                         break;
 103                 case 'o':
 104                         if (cflag || pflag || rflag || sflag)
 105                                 usage();
 106                         oflag = 1; /* output to the specified file */
 107                         sflag = 1; /* do not strip pathnames for output */
 108                         outfile = optarg; /* set the output filename */
 109                         break;
 110                 case 'p':
 111                         if (oflag)
 112                                 usage();
 113                         pflag = 1; /* print output to stdout */
 114                         break;
 115                 case 'r':
 116                         if (cflag || oflag)
 117                                 usage();
 118                         rflag = 1; /* decode raw data */
 119                         break;
 120                 case 's':
 121                         if (oflag)
 122                                 usage();
 123                         sflag = 1; /* do not strip pathnames for output */
 124                         break;
 125                 default:
 126                         usage();
 127                 }
 128         }
 129         argc -= optind;
 130         argv += optind;
 131
 132         if (*argv != NULL) {
 133                 rval = 0;
 134                 do {
 135                         infp = fopen(infile = *argv, "r");
 136                         if (infp == NULL) {
 137                                 warn("%s", *argv);
 138                                 rval = 1;
 139                                 continue;
 140                         }
 141                         rval |= decode();
 142                         fclose(infp);
 143                 } while (*++argv);
 144         } else {
 145                 infile = "stdin";
 146                 infp = stdin;
 147                 rval = decode();
 148         }
 149         exit(rval);
 150 }
 151
 152 static int
 153 decode(void)
 154 {
 155         int r, v;
 156
 157         if (rflag) {
 158                 /* relaxed alternative to decode2() */
 159                 outfile = "/dev/stdout";
 160                 outfp = stdout;
 161                 if (base64)
 162                         return (base64_decode());
 163                 else
 164                         return (uu_decode());
 165         }
 166         v = decode2();
 167         if (v == EOF) {
 168                 warnx("%s: missing or bad \"begin\" line", infile);
 169                 return (1);
 170         }
 171         for (r = v; cflag; r |= v) {
 172                 v = decode2();
 173                 if (v == EOF)
 174                         break;
 175         }
 176         return (r);
 177 }
 178
 179 static int
 180 decode2(void)
 181 {
 182         int flags, fd, mode;
 183         size_t n, m;
 184         char *p, *q;
 185         void *handle;
 186         struct passwd *pw;
 187         struct stat st;
 188         char buf[MAXPATHLEN + 1];
 189
 190         base64 = 0;
 191         /* search for header line */
 192         for (;;) {
 193                 if (fgets(buf, sizeof(buf), infp) == NULL)
 194                         return (EOF);
 195                 p = buf;
 196                 if (strncmp(p, "begin-base64 ", 13) == 0) {
 197                         base64 = 1;
 198                         p += 13;
 199                 } else if (strncmp(p, "begin ", 6) == 0)
 200                         p += 6;
 201                 else
 202                         continue;
 203                 /* p points to mode */
 204                 q = strchr(p, ' ');
 205                 if (q == NULL)
 206                         continue;
 207                 *q++ = '\0';
 208                 /* q points to filename */
 209                 n = strlen(q);
 210                 while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
 211                         q[--n] = '\0';
 212                 /* found valid header? */
 213                 if (n > 0)
 214                         break;
 215         }
 216
 217         handle = setmode(p);
 218         if (handle == NULL) {
 219                 warnx("%s: unable to parse file mode", infile);
 220                 return (1);
 221         }
 222         mode = getmode(handle, 0) & 0666;
 223         free(handle);
 224
 225         if (sflag) {
 226                 /* don't strip, so try ~user/file expansion */
 227                 p = NULL;
 228                 pw = NULL;
 229                 if (*q == '~')
 230                         p = strchr(q, '/');
 231                 if (p != NULL) {
 232                         *p = '\0';
 233                         pw = getpwnam(q + 1);
 234                         *p = '/';
 235                 }
 236                 if (pw != NULL) {
 237                         n = strlen(pw->pw_dir);
 238                         if (buf + n > p) {
 239                                 /* make room */
 240                                 m = strlen(p);
 241                                 if (sizeof(buf) < n + m) {
 242                                         warnx("%s: bad output filename",
 243                                             infile);
 244                                         return (1);
 245                                 }
 246                                 p = memmove(buf + n, p, m);
 247                         }
 248                         q = memcpy(p - n, pw->pw_dir, n);
 249                 }
 250         } else {
 251                 /* strip down to leaf name */
 252                 p = strrchr(q, '/');
 253                 if (p != NULL)
 254                         q = p + 1;
 255         }
 256         if (!oflag)
 257                 outfile = q;
 258
 259         /* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
 260         if (pflag || strcmp(outfile, "/dev/stdout") == 0)
 261                 outfp = stdout;
 262         else {
 263                 flags = O_WRONLY | O_CREAT | O_EXCL;
 264                 if (lstat(outfile, &st) == 0) {
 265                         if (iflag) {
 266                                 warnc(EEXIST, "%s: %s", infile, outfile);
 267                                 return (0);
 268                         }
 269                         switch (st.st_mode & S_IFMT) {
 270                         case S_IFREG:
 271                         case S_IFLNK:
 272                                 /* avoid symlink attacks */
 273                                 if (unlink(outfile) == 0 || errno == ENOENT)
 274                                         break;
 275                                 warn("%s: unlink %s", infile, outfile);
 276                                 return (1);
 277                         case S_IFDIR:
 278                                 warnc(EISDIR, "%s: %s", infile, outfile);
 279                                 return (1);
 280                         default:
 281                                 if (oflag) {
 282                                         /* trust command-line names */
 283                                         flags &= ~O_EXCL;
 284                                         break;
 285                                 }
 286                                 warnc(EEXIST, "%s: %s", infile, outfile);
 287                                 return (1);
 288                         }
 289                 } else if (errno != ENOENT) {
 290                         warn("%s: %s", infile, outfile);
 291                         return (1);
 292                 }
 293                 if ((fd = open(outfile, flags, mode)) < 0 ||
 294                     (outfp = fdopen(fd, "w")) == NULL) {
 295                         warn("%s: %s", infile, outfile);
 296                         return (1);
 297                 }
 298         }
 299
 300         if (base64)
 301                 return (base64_decode());
 302         else
 303                 return (uu_decode());
 304 }
 305
 306 static int
 307 getline(char *buf, size_t size)
 308 {
 309
 310         if (fgets(buf, size, infp) != NULL)
 311                 return (2);
 312         if (rflag)
 313                 return (0);
 314         warnx("%s: %s: short file", infile, outfile);
 315         return (1);
 316 }
 317
 318 static int
 319 checkend(const char *ptr, const char *end, const char *msg)
 320 {
 321         size_t n;
 322
 323         n = strlen(end);
 324         if (strncmp(ptr, end, n) != 0 ||
 325             strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
 326                 warnx("%s: %s: %s", infile, outfile, msg);
 327                 return (1);
 328         }
 329         if (fclose(outfp) != 0) {
 330                 warn("%s: %s", infile, outfile);
 331                 return (1);
 332         }
 333         return (0);
 334 }
 335
 336 static int
 337 uu_decode(void)
 338 {
 339         int i, ch;
 340         char *p;
 341         char buf[MAXPATHLEN+1];
 342
 343         /* for each input line */
 344         for (;;) {
 345                 switch (getline(buf, sizeof(buf))) {
 346                 case 0:
 347                         return (0);
 348                 case 1:
 349                         return (1);
 350                 }
 351
 352 #define DEC(c)          (((c) - ' ') & 077)     /* single character decode */
 353 #define IS_DEC(c)        ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
 354
 355 #define OUT_OF_RANGE do {                                               \
 356         warnx("%s: %s: character out of range: [%d-%d]",                \
 357             infile, outfile, 1 + ' ', 077 + ' ' + 1);                   \
 358         return (1);                                                     \
 359 } while (0)
 360
 361                 /*
 362                  * `i' is used to avoid writing out all the characters
 363                  * at the end of the file.
 364                  */
 365                 p = buf;
 366                 if ((i = DEC(*p)) <= 0)
 367                         break;
 368                 for (++p; i > 0; p += 4, i -= 3)
 369                         if (i >= 3) {
 370                                 if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
 371                                     IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
 372                                         OUT_OF_RANGE;
 373
 374                                 ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 375                                 putc(ch, outfp);
 376                                 ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 377                                 putc(ch, outfp);
 378                                 ch = DEC(p[2]) << 6 | DEC(p[3]);
 379                                 putc(ch, outfp);
 380                         } else {
 381                                 if (i >= 1) {
 382                                         if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
 383                                                 OUT_OF_RANGE;
 384                                         ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 385                                         putc(ch, outfp);
 386                                 }
 387                                 if (i >= 2) {
 388                                         if (!(IS_DEC(*(p + 1)) &&
 389                                             IS_DEC(*(p + 2))))
 390                                                 OUT_OF_RANGE;
 391
 392                                         ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 393                                         putc(ch, outfp);
 394                                 }
 395                                 if (i >= 3) {
 396                                         if (!(IS_DEC(*(p + 2)) &&
 397                                             IS_DEC(*(p + 3))))
 398                                                 OUT_OF_RANGE;
 399                                         ch = DEC(p[2]) << 6 | DEC(p[3]);
 400                                         putc(ch, outfp);
 401                                 }
 402                         }
 403         }
 404         switch (getline(buf, sizeof(buf))) {
 405         case 0:
 406                 return (0);
 407         case 1:
 408                 return (1);
 409         default:
 410                 return (checkend(buf, "end", "no \"end\" line"));
 411         }
 412 }
 413
 414 static int
 415 base64_decode(void)
 416 {
 417         int n, count, count4;
 418         char inbuf[MAXPATHLEN + 1], *p;
 419         unsigned char outbuf[MAXPATHLEN * 4];
 420         char leftover[MAXPATHLEN + 1];
 421
 422         leftover[0] = '\0';
 423         for (;;) {
 424                 strcpy(inbuf, leftover);
 425                 switch (getline(inbuf + strlen(inbuf),
 426                     sizeof(inbuf) - strlen(inbuf))) {
 427                 case 0:
 428                         return (0);
 429                 case 1:
 430                         return (1);
 431                 }
 432
 433                 count = 0;
 434                 count4 = -1;
 435                 p = inbuf;
 436                 while (*p != '\0') {
 437                         /*
 438                          * Base64 encoded strings have the following
 439                          * characters in them: A-Z, a-z, 0-9 and +, / and =
 440                          */
 441                         if (isalnum(*p) || *p == '+' || *p == '/' || *p == '=')
 442                                 count++;
 443                         if (count % 4 == 0)
 444                                 count4 = p - inbuf;
 445                         p++;
 446                 }
 447
 448                 strcpy(leftover, inbuf + count4 + 1);
 449                 inbuf[count4 + 1] = 0;
 450
 451                 n = b64_pton(inbuf, outbuf, sizeof(outbuf));
 452
 453                 if (n < 0)
 454                         break;
 455                 fwrite(outbuf, 1, n, outfp);
 456         }
 457         return (checkend(inbuf, "====", "error decoding base64 input stream"));
 458 }
 459
 460 static void
 461 usage(void)
 462 {
 463
 464         (void)fprintf(stderr,
 465             "usage: uudecode [-cimprs] [file ...]\n"
 466             "       uudecode [-i] -o output_file [file]\n"
 467             "       b64decode [-cimprs] [file ...]\n"
 468             "       b64decode [-i] -o output_file [file]\n");
 469         exit(1);
 470 }