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 static const char *infile, *outfile;
  58 static FILE *infp, *outfp;
  59 static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
  60
  61 static void     usage(void);
  62 static int      decode(void);
  63 static int      decode2(void);
  64 static int      uu_decode(void);
  65 static int      base64_decode(void);
  66
  67 int
  68 main(int argc, char *argv[])
  69 {
  70         int rval, ch;
  71
  72         if (strcmp(basename(argv[0]), "b64decode") == 0)
  73                 base64 = 1;
  74
  75         while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
  76                 switch (ch) {
  77                 case 'c':
  78                         if (oflag || rflag)
  79                                 usage();
  80                         cflag = 1; /* multiple uudecode'd files */
  81                         break;
  82                 case 'i':
  83                         iflag = 1; /* ask before override files */
  84                         break;
  85                 case 'm':
  86                         base64 = 1;
  87                         break;
  88                 case 'o':
  89                         if (cflag || pflag || rflag || sflag)
  90                                 usage();
  91                         oflag = 1; /* output to the specified file */
  92                         sflag = 1; /* do not strip pathnames for output */
  93                         outfile = optarg; /* set the output filename */
  94                         break;
  95                 case 'p':
  96                         if (oflag)
  97                                 usage();
  98                         pflag = 1; /* print output to stdout */
  99                         break;
 100                 case 'r':
 101                         if (cflag || oflag)
 102                                 usage();
 103                         rflag = 1; /* decode raw data */
 104                         break;
 105                 case 's':
 106                         if (oflag)
 107                                 usage();
 108                         sflag = 1; /* do not strip pathnames for output */
 109                         break;
 110                 default:
 111                         usage();
 112                 }
 113         }
 114         argc -= optind;
 115         argv += optind;
 116
 117         if (*argv != NULL) {
 118                 rval = 0;
 119                 do {
 120                         infp = fopen(infile = *argv, "r");
 121                         if (infp == NULL) {
 122                                 warn("%s", *argv);
 123                                 rval = 1;
 124                                 continue;
 125                         }
 126                         rval |= decode();
 127                         fclose(infp);
 128                 } while (*++argv);
 129         } else {
 130                 infile = "stdin";
 131                 infp = stdin;
 132                 rval = decode();
 133         }
 134         exit(rval);
 135 }
 136
 137 static int
 138 decode(void)
 139 {
 140         int r, v;
 141
 142         if (rflag) {
 143                 /* relaxed alternative to decode2() */
 144                 outfile = "/dev/stdout";
 145                 outfp = stdout;
 146                 if (base64)
 147                         return (base64_decode());
 148                 else
 149                         return (uu_decode());
 150         }
 151         v = decode2();
 152         if (v == EOF) {
 153                 warnx("%s: missing or bad \"begin\" line", infile);
 154                 return (1);
 155         }
 156         for (r = v; cflag; r |= v) {
 157                 v = decode2();
 158                 if (v == EOF)
 159                         break;
 160         }
 161         return (r);
 162 }
 163
 164 static int
 165 decode2(void)
 166 {
 167         int flags, fd;
 168         size_t n, m;
 169         char *p, *q;
 170         void *handle;
 171         mode_t mode;
 172         struct passwd *pw;
 173         struct stat st;
 174         char buf[MAXPATHLEN + 1];
 175
 176         base64 = 0;
 177         /* search for header line */
 178         for (;;) {
 179                 if (fgets(buf, sizeof(buf), infp) == NULL)
 180                         return (EOF);
 181                 p = buf;
 182                 if (strncmp(p, "begin-base64 ", 13) == 0) {
 183                         base64 = 1;
 184                         p += 13;
 185                 } else if (strncmp(p, "begin ", 6) == 0)
 186                         p += 6;
 187                 else
 188                         continue;
 189                 /* p points to mode */
 190                 q = strchr(p, ' ');
 191                 if (q == NULL)
 192                         continue;
 193                 *q++ = '\0';
 194                 /* q points to filename */
 195                 n = strlen(q);
 196                 while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
 197                         q[--n] = '\0';
 198                 /* found valid header? */
 199                 if (n > 0)
 200                         break;
 201         }
 202
 203         errno = 0;
 204         if ((handle = setmode(p)) == NULL) {
 205                 if (!errno)
 206                         warnx("invalid file mode: %s", infile);
 207                 else
 208                         warn("setmode malloc failed: %s", infile);
 209
 210                 return (1);
 211         }
 212
 213         mode = getmode(handle, 0) & 0666;
 214         free(handle);
 215
 216         if (sflag) {
 217                 /* don't strip, so try ~user/file expansion */
 218                 p = NULL;
 219                 pw = NULL;
 220                 if (*q == '~')
 221                         p = strchr(q, '/');
 222                 if (p != NULL) {
 223                         *p = '\0';
 224                         pw = getpwnam(q + 1);
 225                         *p = '/';
 226                 }
 227                 if (pw != NULL) {
 228                         n = strlen(pw->pw_dir);
 229                         if (buf + n > p) {
 230                                 /* make room */
 231                                 m = strlen(p);
 232                                 if (sizeof(buf) < n + m) {
 233                                         warnx("%s: bad output filename",
 234                                             infile);
 235                                         return (1);
 236                                 }
 237                                 p = memmove(buf + n, p, m);
 238                         }
 239                         q = memcpy(p - n, pw->pw_dir, n);
 240                 }
 241         } else {
 242                 /* strip down to leaf name */
 243                 p = strrchr(q, '/');
 244                 if (p != NULL)
 245                         q = p + 1;
 246         }
 247         if (!oflag)
 248                 outfile = q;
 249
 250         /* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
 251         if (pflag || strcmp(outfile, "/dev/stdout") == 0)
 252                 outfp = stdout;
 253         else {
 254                 flags = O_WRONLY | O_CREAT | O_EXCL;
 255                 if (lstat(outfile, &st) == 0) {
 256                         if (iflag) {
 257                                 warnc(EEXIST, "%s: %s", infile, outfile);
 258                                 return (0);
 259                         }
 260                         switch (st.st_mode & S_IFMT) {
 261                         case S_IFREG:
 262                         case S_IFLNK:
 263                                 /* avoid symlink attacks */
 264                                 if (unlink(outfile) == 0 || errno == ENOENT)
 265                                         break;
 266                                 warn("%s: unlink %s", infile, outfile);
 267                                 return (1);
 268                         case S_IFDIR:
 269                                 warnc(EISDIR, "%s: %s", infile, outfile);
 270                                 return (1);
 271                         default:
 272                                 if (oflag) {
 273                                         /* trust command-line names */
 274                                         flags &= ~O_EXCL;
 275                                         break;
 276                                 }
 277                                 warnc(EEXIST, "%s: %s", infile, outfile);
 278                                 return (1);
 279                         }
 280                 } else if (errno != ENOENT) {
 281                         warn("%s: %s", infile, outfile);
 282                         return (1);
 283                 }
 284                 if ((fd = open(outfile, flags, mode)) < 0 ||
 285                     (outfp = fdopen(fd, "w")) == NULL) {
 286                         warn("%s: %s", infile, outfile);
 287                         return (1);
 288                 }
 289         }
 290
 291         if (base64)
 292                 return (base64_decode());
 293         else
 294                 return (uu_decode());
 295 }
 296
 297 static int
 298 get_line(char *buf, size_t size)
 299 {
 300         if (fgets(buf, size, infp) != NULL)
 301                 return (2);
 302         if (rflag)
 303                 return (0);
 304         warnx("%s: %s: short file", infile, outfile);
 305         return (1);
 306 }
 307
 308 static int
 309 checkend(const char *ptr, const char *end, const char *msg)
 310 {
 311         size_t n;
 312
 313         n = strlen(end);
 314         if (strncmp(ptr, end, n) != 0 ||
 315             strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
 316                 warnx("%s: %s: %s", infile, outfile, msg);
 317                 return (1);
 318         }
 319         if (fclose(outfp) != 0) {
 320                 warn("%s: %s", infile, outfile);
 321                 return (1);
 322         }
 323         return (0);
 324 }
 325
 326 static int
 327 uu_decode(void)
 328 {
 329         int i, ch;
 330         char *p;
 331         char buf[MAXPATHLEN+1];
 332
 333         /* for each input line */
 334         for (;;) {
 335                 switch (get_line(buf, sizeof(buf))) {
 336                 case 0:
 337                         return (0);
 338                 case 1:
 339                         return (1);
 340                 }
 341
 342 #define DEC(c)          (((c) - ' ') & 077)     /* single character decode */
 343 #define IS_DEC(c)       ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
 344
 345 #define OUT_OF_RANGE do {                                               \
 346         warnx("%s: %s: character out of range: [%d-%d]",                \
 347             infile, outfile, 1 + ' ', 077 + ' ' + 1);                   \
 348         return (1);                                                     \
 349 } while (0)
 350
 351                 /*
 352                  * `i' is used to avoid writing out all the characters
 353                  * at the end of the file.
 354                  */
 355                 p = buf;
 356                 if ((i = DEC(*p)) <= 0)
 357                         break;
 358                 for (++p; i > 0; p += 4, i -= 3)
 359                         if (i >= 3) {
 360                                 if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
 361                                     IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
 362                                         OUT_OF_RANGE;
 363
 364                                 ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 365                                 putc(ch, outfp);
 366                                 ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 367                                 putc(ch, outfp);
 368                                 ch = DEC(p[2]) << 6 | DEC(p[3]);
 369                                 putc(ch, outfp);
 370                         } else {
 371                                 if (i >= 1) {
 372                                         if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
 373                                                 OUT_OF_RANGE;
 374                                         ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 375                                         putc(ch, outfp);
 376                                 }
 377                                 if (i >= 2) {
 378                                         if (!(IS_DEC(*(p + 1)) &&
 379                                             IS_DEC(*(p + 2))))
 380                                                 OUT_OF_RANGE;
 381
 382                                         ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 383                                         putc(ch, outfp);
 384                                 }
 385                                 if (i >= 3) {
 386                                         if (!(IS_DEC(*(p + 2)) &&
 387                                             IS_DEC(*(p + 3))))
 388                                                 OUT_OF_RANGE;
 389                                         ch = DEC(p[2]) << 6 | DEC(p[3]);
 390                                         putc(ch, outfp);
 391                                 }
 392                         }
 393         }
 394         switch (get_line(buf, sizeof(buf))) {
 395         case 0:
 396                 return (0);
 397         case 1:
 398                 return (1);
 399         default:
 400                 return (checkend(buf, "end", "no \"end\" line"));
 401         }
 402 }
 403
 404 static int
 405 base64_decode(void)
 406 {
 407         int n;
 408         char inbuf[MAXPATHLEN + 1];
 409         unsigned char outbuf[MAXPATHLEN * 4];
 410
 411         for (;;) {
 412                 switch (get_line(inbuf, sizeof(inbuf))) {
 413                 case 0:
 414                         return (0);
 415                 case 1:
 416                         return (1);
 417                 }
 418
 419                 n = b64_pton(inbuf, outbuf, sizeof(outbuf));
 420
 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 }