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