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  * @(#) Copyright (c) 1983, 1993 The Regents of the University of California.  All rights reserved.
  34  * @(#)uudecode.c       8.2 (Berkeley) 4/2/94
  35  * $FreeBSD: src/usr.bin/uudecode/uudecode.c,v 1.13.2.6 2003/04/07 20:10:33 fanf Exp $
  36  * $DragonFly: src/usr.bin/uudecode/uudecode.c,v 1.3 2004/12/22 11:25:51 liamfoy Exp $
  37  */
  38
  39 /*
  40  * uudecode [file ...]
  41  *
  42  * create the specified file, decoding as you go.
  43  * used with uuencode.
  44  */
  45 #include <sys/param.h>
  46 #include <sys/socket.h>
  47 #include <sys/stat.h>
  48
  49 #include <netinet/in.h>
  50
  51 #include <err.h>
  52 #include <errno.h>
  53 #include <fcntl.h>
  54 #include <libgen.h>
  55 #include <pwd.h>
  56 #include <resolv.h>
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60 #include <unistd.h>
  61
  62 static const char *infile, *outfile;
  63 static FILE *infp, *outfp;
  64 static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
  65
  66 static void     usage(void);
  67 static int      decode(void);
  68 static int      decode2(void);
  69 static int      uu_decode(void);
  70 static int      base64_decode(void);
  71
  72 int
  73 main(int argc, char *argv[])
  74 {
  75         int rval, ch;
  76
  77         if (strcmp(basename(argv[0]), "b64decode") == 0)
  78                 base64 = 1;
  79
  80         while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
  81                 switch(ch) {
  82                 case 'c':
  83                         if (oflag || rflag)
  84                                 usage();
  85                         cflag = 1; /* multiple uudecode'd files */
  86                         break;
  87                 case 'i':
  88                         iflag = 1; /* ask before override files */
  89                         break;
  90                 case 'm':
  91                         base64 = 1;
  92                         break;
  93                 case 'o':
  94                         if (cflag || pflag || rflag || sflag)
  95                                 usage();
  96                         oflag = 1; /* output to the specified file */
  97                         sflag = 1; /* do not strip pathnames for output */
  98                         outfile = optarg; /* set the output filename */
  99                         break;
 100                 case 'p':
 101                         if (oflag)
 102                                 usage();
 103                         pflag = 1; /* print output to stdout */
 104                         break;
 105                 case 'r':
 106                         if (cflag || oflag)
 107                                 usage();
 108                         rflag = 1; /* decode raw data */
 109                         break;
 110                 case 's':
 111                         if (oflag)
 112                                 usage();
 113                         sflag = 1; /* do not strip pathnames for output */
 114                         break;
 115                 default:
 116                         usage();
 117                 }
 118         }
 119         argc -= optind;
 120         argv += optind;
 121
 122         if (*argv) {
 123                 rval = 0;
 124                 do {
 125                         infp = fopen(infile = *argv, "r");
 126                         if (infp == NULL) {
 127                                 warn("%s", *argv);
 128                                 rval = 1;
 129                                 continue;
 130                         }
 131                         rval |= decode();
 132                         fclose(infp);
 133                 } while (*++argv);
 134         } else {
 135                 infile = "stdin";
 136                 infp = stdin;
 137                 rval = decode();
 138         }
 139         exit(rval);
 140 }
 141
 142 static int
 143 decode(void)
 144 {
 145         int r, v;
 146
 147         if (rflag) {
 148                 /* relaxed alternative to decode2() */
 149                 outfile = "/dev/stdout";
 150                 outfp = stdout;
 151                 if (base64)
 152                         return (base64_decode());
 153                 else
 154                         return (uu_decode());
 155         }
 156         v = decode2();
 157         if (v == EOF) {
 158                 warnx("%s: missing or bad \"begin\" line", infile);
 159                 return (1);
 160         }
 161         for (r = v; cflag; r |= v) {
 162                 v = decode2();
 163                 if (v == EOF)
 164                         break;
 165         }
 166         return (r);
 167 }
 168
 169 static int
 170 decode2(void)
 171 {
 172         int flags, fd;
 173         size_t n, m;
 174         char *p, *q;
 175         void *handle;
 176         mode_t mode;
 177         struct passwd *pw;
 178         struct stat st;
 179         char buf[MAXPATHLEN+1];
 180
 181         base64 = 0;
 182         /* search for header line */
 183         for (;;) {
 184                 if (fgets(buf, sizeof(buf), infp) == NULL)
 185                         return (EOF);
 186                 p = buf;
 187                 if (strncmp(p, "begin-base64 ", 13) == 0) {
 188                         base64 = 1;
 189                         p += 13;
 190                 } else if (strncmp(p, "begin ", 6) == 0)
 191                         p += 6;
 192                 else
 193                         continue;
 194                 /* p points to mode */
 195                 q = strchr(p, ' ');
 196                 if (q == NULL)
 197                         continue;
 198                 *q++ = '\0';
 199                 /* q points to filename */
 200                 n = strlen(q);
 201                 while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
 202                         q[--n] = '\0';
 203                 /* found valid header? */
 204                 if (n > 0)
 205                         break;
 206         }
 207
 208         errno = 0;
 209         if ((handle = setmode(p)) == NULL) {
 210                 if (!errno)
 211                         warnx("invalid file mode: %s", infile);
 212                 else
 213                         warn("setmode malloc failed: %s", infile);
 214
 215                 return(1);
 216         }
 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         if (fgets(buf, size, infp) != NULL)
 306                 return (2);
 307         if (rflag)
 308                 return (0);
 309         warnx("%s: %s: short file", infile, outfile);
 310         return (1);
 311 }
 312
 313 static int
 314 checkend(const char *ptr, const char *end, const char *msg)
 315 {
 316         size_t n;
 317
 318         n = strlen(end);
 319         if (strncmp(ptr, end, n) != 0 ||
 320             strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
 321                 warnx("%s: %s: %s", infile, outfile, msg);
 322                 return (1);
 323         }
 324         if (fclose(outfp) != 0) {
 325                 warn("%s: %s", infile, outfile);
 326                 return (1);
 327         }
 328         return (0);
 329 }
 330
 331 static int
 332 uu_decode(void)
 333 {
 334         int i, ch;
 335         char *p;
 336         char buf[MAXPATHLEN+1];
 337
 338         /* for each input line */
 339         for (;;) {
 340                 switch (getline(buf, sizeof(buf))) {
 341                 case 0: return (0);
 342                 case 1: return (1);
 343                 }
 344
 345 #define DEC(c)  (((c) - ' ') & 077)             /* single character decode */
 346 #define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
 347
 348 #define OUT_OF_RANGE do {                                               \
 349         warnx("%s: %s: character out of range: [%d-%d]",                \
 350             infile, outfile, 1 + ' ', 077 + ' ' + 1);                   \
 351         return (1);                                                     \
 352 } while (0)
 353
 354                 /*
 355                  * `i' is used to avoid writing out all the characters
 356                  * at the end of the file.
 357                  */
 358                 p = buf;
 359                 if ((i = DEC(*p)) <= 0)
 360                         break;
 361                 for (++p; i > 0; p += 4, i -= 3)
 362                         if (i >= 3) {
 363                                 if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
 364                                      IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
 365                                         OUT_OF_RANGE;
 366
 367                                 ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 368                                 putc(ch, outfp);
 369                                 ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 370                                 putc(ch, outfp);
 371                                 ch = DEC(p[2]) << 6 | DEC(p[3]);
 372                                 putc(ch, outfp);
 373                         }
 374                         else {
 375                                 if (i >= 1) {
 376                                         if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
 377                                                 OUT_OF_RANGE;
 378                                         ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 379                                         putc(ch, outfp);
 380                                 }
 381                                 if (i >= 2) {
 382                                         if (!(IS_DEC(*(p + 1)) &&
 383                                                 IS_DEC(*(p + 2))))
 384                                                 OUT_OF_RANGE;
 385
 386                                         ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 387                                         putc(ch, outfp);
 388                                 }
 389                                 if (i >= 3) {
 390                                         if (!(IS_DEC(*(p + 2)) &&
 391                                                 IS_DEC(*(p + 3))))
 392                                                 OUT_OF_RANGE;
 393                                         ch = DEC(p[2]) << 6 | DEC(p[3]);
 394                                         putc(ch, outfp);
 395                                 }
 396                         }
 397         }
 398         switch (getline(buf, sizeof(buf))) {
 399         case 0:  return (0);
 400         case 1:  return (1);
 401         default: return (checkend(buf, "end", "no \"end\" line"));
 402         }
 403 }
 404
 405 static int
 406 base64_decode(void)
 407 {
 408         int n;
 409         char inbuf[MAXPATHLEN+1];
 410         unsigned char outbuf[MAXPATHLEN * 4];
 411
 412         for (;;) {
 413                 switch (getline(inbuf, sizeof(inbuf))) {
 414                 case 0: return (0);
 415                 case 1: return (1);
 416                 }
 417                 n = b64_pton(inbuf, outbuf, sizeof(outbuf));
 418                 if (n < 0)
 419                         break;
 420                 fwrite(outbuf, 1, n, outfp);
 421         }
 422         return (checkend(inbuf, "====",
 423                     "error decoding base64 input stream"));
 424 }
 425
 426 static void
 427 usage(void)
 428 {
 429         (void)fprintf(stderr,
 430 "usage: uudecode [-cimprs] [file ...]\n"
 431 "       uudecode [-i] -o output_file [file]\n"
 432 "       b64decode [-cimprs] [file ...]\n"
 433 "       b64decode [-i] -o output_file [file]\n");
 434         exit(1);
 435 }