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. 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  * @(#) Copyright (c) 1983, 1993 The Regents of the University of California.  All rights reserved.
  30  * @(#)uudecode.c       8.2 (Berkeley) 4/2/94
  31  * $FreeBSD: src/usr.bin/uudecode/uudecode.c,v 1.13.2.6 2003/04/07 20:10:33 fanf Exp $
  32  */
  33
  34 /*
  35  * uudecode [file ...]
  36  *
  37  * create the specified file, decoding as you go.
  38  * used with uuencode.
  39  */
  40 #include <sys/param.h>
  41 #include <sys/socket.h>
  42 #include <sys/stat.h>
  43
  44 #include <netinet/in.h>
  45
  46 #include <err.h>
  47 #include <errno.h>
  48 #include <fcntl.h>
  49 #include <libgen.h>
  50 #include <pwd.h>
  51 #include <resolv.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <unistd.h>
  56
  57 #ifdef BOOTSTRAPPING
  58 #define getline get_line /* help bootstrap previous stdio.h */
  59 #endif
  60
  61 static const char *infile, *outfile;
  62 static FILE *infp, *outfp;
  63 static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
  64
  65 static void     usage(void);
  66 static int      decode(void);
  67 static int      decode2(void);
  68 static int      uu_decode(void);
  69 static int      base64_decode(void);
  70
  71 int
  72 main(int argc, char *argv[])
  73 {
  74         int rval, ch;
  75
  76         if (strcmp(basename(argv[0]), "b64decode") == 0)
  77                 base64 = 1;
  78
  79         while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
  80                 switch (ch) {
  81                 case 'c':
  82                         if (oflag || rflag)
  83                                 usage();
  84                         cflag = 1; /* multiple uudecode'd files */
  85                         break;
  86                 case 'i':
  87                         iflag = 1; /* ask before override files */
  88                         break;
  89                 case 'm':
  90                         base64 = 1;
  91                         break;
  92                 case 'o':
  93                         if (cflag || pflag || rflag || sflag)
  94                                 usage();
  95                         oflag = 1; /* output to the specified file */
  96                         sflag = 1; /* do not strip pathnames for output */
  97                         outfile = optarg; /* set the output filename */
  98                         break;
  99                 case 'p':
 100                         if (oflag)
 101                                 usage();
 102                         pflag = 1; /* print output to stdout */
 103                         break;
 104                 case 'r':
 105                         if (cflag || oflag)
 106                                 usage();
 107                         rflag = 1; /* decode raw data */
 108                         break;
 109                 case 's':
 110                         if (oflag)
 111                                 usage();
 112                         sflag = 1; /* do not strip pathnames for output */
 113                         break;
 114                 default:
 115                         usage();
 116                 }
 117         }
 118         argc -= optind;
 119         argv += optind;
 120
 121         if (*argv != NULL) {
 122                 rval = 0;
 123                 do {
 124                         infp = fopen(infile = *argv, "r");
 125                         if (infp == NULL) {
 126                                 warn("%s", *argv);
 127                                 rval = 1;
 128                                 continue;
 129                         }
 130                         rval |= decode();
 131                         fclose(infp);
 132                 } while (*++argv);
 133         } else {
 134                 infile = "stdin";
 135                 infp = stdin;
 136                 rval = decode();
 137         }
 138         exit(rval);
 139 }
 140
 141 static int
 142 decode(void)
 143 {
 144         int r, v;
 145
 146         if (rflag) {
 147                 /* relaxed alternative to decode2() */
 148                 outfile = "/dev/stdout";
 149                 outfp = stdout;
 150                 if (base64)
 151                         return (base64_decode());
 152                 else
 153                         return (uu_decode());
 154         }
 155         v = decode2();
 156         if (v == EOF) {
 157                 warnx("%s: missing or bad \"begin\" line", infile);
 158                 return (1);
 159         }
 160         for (r = v; cflag; r |= v) {
 161                 v = decode2();
 162                 if (v == EOF)
 163                         break;
 164         }
 165         return (r);
 166 }
 167
 168 static int
 169 decode2(void)
 170 {
 171         int flags, fd;
 172         size_t n, m;
 173         char *p, *q;
 174         void *handle;
 175         mode_t mode;
 176         struct passwd *pw;
 177         struct stat st;
 178         char buf[MAXPATHLEN + 1];
 179
 180         base64 = 0;
 181         /* search for header line */
 182         for (;;) {
 183                 if (fgets(buf, sizeof(buf), infp) == NULL)
 184                         return (EOF);
 185                 p = buf;
 186                 if (strncmp(p, "begin-base64 ", 13) == 0) {
 187                         base64 = 1;
 188                         p += 13;
 189                 } else if (strncmp(p, "begin ", 6) == 0)
 190                         p += 6;
 191                 else
 192                         continue;
 193                 /* p points to mode */
 194                 q = strchr(p, ' ');
 195                 if (q == NULL)
 196                         continue;
 197                 *q++ = '\0';
 198                 /* q points to filename */
 199                 n = strlen(q);
 200                 while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
 201                         q[--n] = '\0';
 202                 /* found valid header? */
 203                 if (n > 0)
 204                         break;
 205         }
 206
 207         errno = 0;
 208         if ((handle = setmode(p)) == NULL) {
 209                 if (!errno)
 210                         warnx("invalid file mode: %s", infile);
 211                 else
 212                         warn("setmode malloc failed: %s", infile);
 213
 214                 return (1);
 215         }
 216
 217         mode = getmode(handle, 0) & 0666;
 218         free(handle);
 219
 220         if (sflag) {
 221                 /* don't strip, so try ~user/file expansion */
 222                 p = NULL;
 223                 pw = NULL;
 224                 if (*q == '~')
 225                         p = strchr(q, '/');
 226                 if (p != NULL) {
 227                         *p = '\0';
 228                         pw = getpwnam(q + 1);
 229                         *p = '/';
 230                 }
 231                 if (pw != NULL) {
 232                         n = strlen(pw->pw_dir);
 233                         if (buf + n > p) {
 234                                 /* make room */
 235                                 m = strlen(p);
 236                                 if (sizeof(buf) < n + m) {
 237                                         warnx("%s: bad output filename",
 238                                             infile);
 239                                         return (1);
 240                                 }
 241                                 p = memmove(buf + n, p, m);
 242                         }
 243                         q = memcpy(p - n, pw->pw_dir, n);
 244                 }
 245         } else {
 246                 /* strip down to leaf name */
 247                 p = strrchr(q, '/');
 248                 if (p != NULL)
 249                         q = p + 1;
 250         }
 251         if (!oflag)
 252                 outfile = q;
 253
 254         /* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
 255         if (pflag || strcmp(outfile, "/dev/stdout") == 0)
 256                 outfp = stdout;
 257         else {
 258                 flags = O_WRONLY | O_CREAT | O_EXCL;
 259                 if (lstat(outfile, &st) == 0) {
 260                         if (iflag) {
 261                                 warnc(EEXIST, "%s: %s", infile, outfile);
 262                                 return (0);
 263                         }
 264                         switch (st.st_mode & S_IFMT) {
 265                         case S_IFREG:
 266                         case S_IFLNK:
 267                                 /* avoid symlink attacks */
 268                                 if (unlink(outfile) == 0 || errno == ENOENT)
 269                                         break;
 270                                 warn("%s: unlink %s", infile, outfile);
 271                                 return (1);
 272                         case S_IFDIR:
 273                                 warnc(EISDIR, "%s: %s", infile, outfile);
 274                                 return (1);
 275                         default:
 276                                 if (oflag) {
 277                                         /* trust command-line names */
 278                                         flags &= ~O_EXCL;
 279                                         break;
 280                                 }
 281                                 warnc(EEXIST, "%s: %s", infile, outfile);
 282                                 return (1);
 283                         }
 284                 } else if (errno != ENOENT) {
 285                         warn("%s: %s", infile, outfile);
 286                         return (1);
 287                 }
 288                 if ((fd = open(outfile, flags, mode)) < 0 ||
 289                     (outfp = fdopen(fd, "w")) == NULL) {
 290                         warn("%s: %s", infile, outfile);
 291                         return (1);
 292                 }
 293         }
 294
 295         if (base64)
 296                 return (base64_decode());
 297         else
 298                 return (uu_decode());
 299 }
 300
 301 static int
 302 get_line(char *buf, size_t size)
 303 {
 304         if (fgets(buf, size, infp) != NULL)
 305                 return (2);
 306         if (rflag)
 307                 return (0);
 308         warnx("%s: %s: short file", infile, outfile);
 309         return (1);
 310 }
 311
 312 static int
 313 checkend(const char *ptr, const char *end, const char *msg)
 314 {
 315         size_t n;
 316
 317         n = strlen(end);
 318         if (strncmp(ptr, end, n) != 0 ||
 319             strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
 320                 warnx("%s: %s: %s", infile, outfile, msg);
 321                 return (1);
 322         }
 323         if (fclose(outfp) != 0) {
 324                 warn("%s: %s", infile, outfile);
 325                 return (1);
 326         }
 327         return (0);
 328 }
 329
 330 static int
 331 uu_decode(void)
 332 {
 333         int i, ch;
 334         char *p;
 335         char buf[MAXPATHLEN+1];
 336
 337         /* for each input line */
 338         for (;;) {
 339                 switch (get_line(buf, sizeof(buf))) {
 340                 case 0:
 341                         return (0);
 342                 case 1:
 343                         return (1);
 344                 }
 345
 346 #define DEC(c)          (((c) - ' ') & 077)     /* single character decode */
 347 #define IS_DEC(c)       ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
 348
 349 #define OUT_OF_RANGE do {                                               \
 350         warnx("%s: %s: character out of range: [%d-%d]",                \
 351             infile, outfile, 1 + ' ', 077 + ' ' + 1);                   \
 352         return (1);                                                     \
 353 } while (0)
 354
 355                 /*
 356                  * `i' is used to avoid writing out all the characters
 357                  * at the end of the file.
 358                  */
 359                 p = buf;
 360                 if ((i = DEC(*p)) <= 0)
 361                         break;
 362                 for (++p; i > 0; p += 4, i -= 3)
 363                         if (i >= 3) {
 364                                 if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
 365                                     IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
 366                                         OUT_OF_RANGE;
 367
 368                                 ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 369                                 putc(ch, outfp);
 370                                 ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 371                                 putc(ch, outfp);
 372                                 ch = DEC(p[2]) << 6 | DEC(p[3]);
 373                                 putc(ch, outfp);
 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 (get_line(buf, sizeof(buf))) {
 399         case 0:
 400                 return (0);
 401         case 1:
 402                 return (1);
 403         default:
 404                 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 (get_line(inbuf, sizeof(inbuf))) {
 417                 case 0:
 418                         return (0);
 419                 case 1:
 420                         return (1);
 421                 }
 422
 423                 n = b64_pton(inbuf, outbuf, sizeof(outbuf));
 424
 425                 if (n < 0)
 426                         break;
 427                 fwrite(outbuf, 1, n, outfp);
 428         }
 429         return (checkend(inbuf, "====",
 430                     "error decoding base64 input stream"));
 431 }
 432
 433 static void
 434 usage(void)
 435 {
 436         (void)fprintf(stderr,
 437 "usage: uudecode [-cimprs] [file ...]\n"
 438 "       uudecode [-i] -o output_file [file]\n"
 439 "       b64decode [-cimprs] [file ...]\n"
 440 "       b64decode [-i] -o output_file [file]\n");
 441         exit(1);
 442 }