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 <err.h>
  61 #include <errno.h>
  62 #include <fcntl.h>
  63 #include <libgen.h>
  64 #include <pwd.h>
  65 #include <resolv.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69 #include <unistd.h>
  70
  71 static const char *infile, *outfile;
  72 static FILE *infp, *outfp;
  73 static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
  74
  75 static void     usage(void);
  76 static int      decode(void);
  77 static int      decode2(void);
  78 static int      uu_decode(void);
  79 static int      base64_decode(void);
  80
  81 int
  82 main(int argc, char *argv[])
  83 {
  84         int rval, ch;
  85
  86         if (strcmp(basename(argv[0]), "b64decode") == 0)
  87                 base64 = 1;
  88
  89         while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
  90                 switch(ch) {
  91                 case 'c':
  92                         if (oflag || rflag)
  93                                 usage();
  94                         cflag = 1; /* multiple uudecode'd files */
  95                         break;
  96                 case 'i':
  97                         iflag = 1; /* ask before override files */
  98                         break;
  99                 case 'm':
 100                         base64 = 1;
 101                         break;
 102                 case 'o':
 103                         if (cflag || pflag || rflag || sflag)
 104                                 usage();
 105                         oflag = 1; /* output to the specified file */
 106                         sflag = 1; /* do not strip pathnames for output */
 107                         outfile = optarg; /* set the output filename */
 108                         break;
 109                 case 'p':
 110                         if (oflag)
 111                                 usage();
 112                         pflag = 1; /* print output to stdout */
 113                         break;
 114                 case 'r':
 115                         if (cflag || oflag)
 116                                 usage();
 117                         rflag = 1; /* decode raw data */
 118                         break;
 119                 case 's':
 120                         if (oflag)
 121                                 usage();
 122                         sflag = 1; /* do not strip pathnames for output */
 123                         break;
 124                 default:
 125                         usage();
 126                 }
 127         }
 128         argc -= optind;
 129         argv += optind;
 130
 131         if (*argv) {
 132                 rval = 0;
 133                 do {
 134                         infp = fopen(infile = *argv, "r");
 135                         if (infp == NULL) {
 136                                 warn("%s", *argv);
 137                                 rval = 1;
 138                                 continue;
 139                         }
 140                         rval |= decode();
 141                         fclose(infp);
 142                 } while (*++argv);
 143         } else {
 144                 infile = "stdin";
 145                 infp = stdin;
 146                 rval = decode();
 147         }
 148         exit(rval);
 149 }
 150
 151 static int
 152 decode(void)
 153 {
 154         int r, v;
 155
 156         if (rflag) {
 157                 /* relaxed alternative to decode2() */
 158                 outfile = "/dev/stdout";
 159                 outfp = stdout;
 160                 if (base64)
 161                         return (base64_decode());
 162                 else
 163                         return (uu_decode());
 164         }
 165         v = decode2();
 166         if (v == EOF) {
 167                 warnx("%s: missing or bad \"begin\" line", infile);
 168                 return (1);
 169         }
 170         for (r = v; cflag; r |= v) {
 171                 v = decode2();
 172                 if (v == EOF)
 173                         break;
 174         }
 175         return (r);
 176 }
 177
 178 static int
 179 decode2(void)
 180 {
 181         int flags, fd, mode;
 182         size_t n, m;
 183         char *p, *q;
 184         void *handle;
 185         struct passwd *pw;
 186         struct stat st;
 187         char buf[MAXPATHLEN+1];
 188
 189         base64 = 0;
 190         /* search for header line */
 191         for (;;) {
 192                 if (fgets(buf, sizeof(buf), infp) == NULL)
 193                         return (EOF);
 194                 p = buf;
 195                 if (strncmp(p, "begin-base64 ", 13) == 0) {
 196                         base64 = 1;
 197                         p += 13;
 198                 } else if (strncmp(p, "begin ", 6) == 0)
 199                         p += 6;
 200                 else
 201                         continue;
 202                 /* p points to mode */
 203                 q = strchr(p, ' ');
 204                 if (q == NULL)
 205                         continue;
 206                 *q++ = '\0';
 207                 /* q points to filename */
 208                 n = strlen(q);
 209                 while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
 210                         q[--n] = '\0';
 211                 /* found valid header? */
 212                 if (n > 0)
 213                         break;
 214         }
 215
 216         handle = setmode(p);
 217         if (handle == NULL) {
 218                 warnx("%s: unable to parse file mode", infile);
 219                 return (1);
 220         }
 221         mode = getmode(handle, 0) & 0666;
 222         free(handle);
 223
 224         if (sflag) {
 225                 /* don't strip, so try ~user/file expansion */
 226                 p = NULL;
 227                 pw = NULL;
 228                 if (*q == '~')
 229                         p = strchr(q, '/');
 230                 if (p != NULL) {
 231                         *p = '\0';
 232                         pw = getpwnam(q + 1);
 233                         *p = '/';
 234                 }
 235                 if (pw != NULL) {
 236                         n = strlen(pw->pw_dir);
 237                         if (buf + n > p) {
 238                                 /* make room */
 239                                 m = strlen(p);
 240                                 if (sizeof(buf) < n + m) {
 241                                         warnx("%s: bad output filename",
 242                                             infile);
 243                                         return (1);
 244                                 }
 245                                 p = memmove(buf + n, p, m);
 246                         }
 247                         q = memcpy(p - n, pw->pw_dir, n);
 248                 }
 249         } else {
 250                 /* strip down to leaf name */
 251                 p = strrchr(q, '/');
 252                 if (p != NULL)
 253                         q = p + 1;
 254         }
 255         if (!oflag)
 256                 outfile = q;
 257
 258         /* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
 259         if (pflag || strcmp(outfile, "/dev/stdout") == 0)
 260                 outfp = stdout;
 261         else {
 262                 flags = O_WRONLY|O_CREAT|O_EXCL;
 263                 if (lstat(outfile, &st) == 0) {
 264                         if (iflag) {
 265                                 warnc(EEXIST, "%s: %s", infile, outfile);
 266                                 return (0);
 267                         }
 268                         switch (st.st_mode & S_IFMT) {
 269                         case S_IFREG:
 270                         case S_IFLNK:
 271                                 /* avoid symlink attacks */
 272                                 if (unlink(outfile) == 0 || errno == ENOENT)
 273                                         break;
 274                                 warn("%s: unlink %s", infile, outfile);
 275                                 return (1);
 276                         case S_IFDIR:
 277                                 warnc(EISDIR, "%s: %s", infile, outfile);
 278                                 return (1);
 279                         default:
 280                                 if (oflag) {
 281                                         /* trust command-line names */
 282                                         flags &= ~O_EXCL;
 283                                         break;
 284                                 }
 285                                 warnc(EEXIST, "%s: %s", infile, outfile);
 286                                 return (1);
 287                         }
 288                 } else if (errno != ENOENT) {
 289                         warn("%s: %s", infile, outfile);
 290                         return (1);
 291                 }
 292                 if ((fd = open(outfile, flags, mode)) < 0 ||
 293                     (outfp = fdopen(fd, "w")) == NULL) {
 294                         warn("%s: %s", infile, outfile);
 295                         return (1);
 296                 }
 297         }
 298
 299         if (base64)
 300                 return (base64_decode());
 301         else
 302                 return (uu_decode());
 303 }
 304
 305 static int
 306 getline(char *buf, size_t size)
 307 {
 308         if (fgets(buf, size, infp) != NULL)
 309                 return (2);
 310         if (rflag)
 311                 return (0);
 312         warnx("%s: %s: short file", infile, outfile);
 313         return (1);
 314 }
 315
 316 static int
 317 checkend(const char *ptr, const char *end, const char *msg)
 318 {
 319         size_t n;
 320
 321         n = strlen(end);
 322         if (strncmp(ptr, end, n) != 0 ||
 323             strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
 324                 warnx("%s: %s: %s", infile, outfile, msg);
 325                 return (1);
 326         }
 327         if (fclose(outfp) != 0) {
 328                 warn("%s: %s", infile, outfile);
 329                 return (1);
 330         }
 331         return (0);
 332 }
 333
 334 static int
 335 uu_decode(void)
 336 {
 337         int i, ch;
 338         char *p;
 339         char buf[MAXPATHLEN+1];
 340
 341         /* for each input line */
 342         for (;;) {
 343                 switch (getline(buf, sizeof(buf))) {
 344                 case 0: return (0);
 345                 case 1: 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                         }
 377                         else {
 378                                 if (i >= 1) {
 379                                         if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
 380                                                 OUT_OF_RANGE;
 381                                         ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 382                                         putc(ch, outfp);
 383                                 }
 384                                 if (i >= 2) {
 385                                         if (!(IS_DEC(*(p + 1)) &&
 386                                                 IS_DEC(*(p + 2))))
 387                                                 OUT_OF_RANGE;
 388
 389                                         ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 390                                         putc(ch, outfp);
 391                                 }
 392                                 if (i >= 3) {
 393                                         if (!(IS_DEC(*(p + 2)) &&
 394                                                 IS_DEC(*(p + 3))))
 395                                                 OUT_OF_RANGE;
 396                                         ch = DEC(p[2]) << 6 | DEC(p[3]);
 397                                         putc(ch, outfp);
 398                                 }
 399                         }
 400         }
 401         switch (getline(buf, sizeof(buf))) {
 402         case 0:  return (0);
 403         case 1:  return (1);
 404         default: return (checkend(buf, "end", "no \"end\" line"));
 405         }
 406 }
 407
 408 static int
 409 base64_decode(void)
 410 {
 411         int n;
 412         char inbuf[MAXPATHLEN+1];
 413         unsigned char outbuf[MAXPATHLEN * 4];
 414
 415         for (;;) {
 416                 switch (getline(inbuf, sizeof(inbuf))) {
 417                 case 0: return (0);
 418                 case 1: return (1);
 419                 }
 420                 n = b64_pton(inbuf, outbuf, sizeof(outbuf));
 421                 if (n < 0)
 422                         break;
 423                 fwrite(outbuf, 1, n, outfp);
 424         }
 425         return (checkend(inbuf, "====",
 426                     "error decoding base64 input stream"));
 427 }
 428
 429 static void
 430 usage(void)
 431 {
 432         (void)fprintf(stderr,
 433 "usage: uudecode [-cimprs] [file ...]\n"
 434 "       uudecode [-i] -o output_file [file]\n"
 435 "       b64decode [-cimprs] [file ...]\n"
 436 "       b64decode [-i] -o output_file [file]\n");
 437         exit(1);
 438 }