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  * @(#) 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  * $DragonFly: src/usr.bin/uudecode/uudecode.c,v 1.3 2004/12/22 11:25:51 liamfoy Exp $
  33  */
  34
  35 /*
  36  * uudecode [file ...]
  37  *
  38  * create the specified file, decoding as you go.
  39  * used with uuencode.
  40  */
  41 #include <sys/param.h>
  42 #include <sys/socket.h>
  43 #include <sys/stat.h>
  44
  45 #include <netinet/in.h>
  46
  47 #include <err.h>
  48 #include <errno.h>
  49 #include <fcntl.h>
  50 #include <libgen.h>
  51 #include <pwd.h>
  52 #include <resolv.h>
  53 #include <stdio.h>
  54 #include <stdlib.h>
  55 #include <string.h>
  56 #include <unistd.h>
  57
  58 static const char *infile, *outfile;
  59 static FILE *infp, *outfp;
  60 static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
  61
  62 static void     usage(void);
  63 static int      decode(void);
  64 static int      decode2(void);
  65 static int      uu_decode(void);
  66 static int      base64_decode(void);
  67
  68 int
  69 main(int argc, char *argv[])
  70 {
  71         int rval, ch;
  72
  73         if (strcmp(basename(argv[0]), "b64decode") == 0)
  74                 base64 = 1;
  75
  76         while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
  77                 switch(ch) {
  78                 case 'c':
  79                         if (oflag || rflag)
  80                                 usage();
  81                         cflag = 1; /* multiple uudecode'd files */
  82                         break;
  83                 case 'i':
  84                         iflag = 1; /* ask before override files */
  85                         break;
  86                 case 'm':
  87                         base64 = 1;
  88                         break;
  89                 case 'o':
  90                         if (cflag || pflag || rflag || sflag)
  91                                 usage();
  92                         oflag = 1; /* output to the specified file */
  93                         sflag = 1; /* do not strip pathnames for output */
  94                         outfile = optarg; /* set the output filename */
  95                         break;
  96                 case 'p':
  97                         if (oflag)
  98                                 usage();
  99                         pflag = 1; /* print output to stdout */
 100                         break;
 101                 case 'r':
 102                         if (cflag || oflag)
 103                                 usage();
 104                         rflag = 1; /* decode raw data */
 105                         break;
 106                 case 's':
 107                         if (oflag)
 108                                 usage();
 109                         sflag = 1; /* do not strip pathnames for output */
 110                         break;
 111                 default:
 112                         usage();
 113                 }
 114         }
 115         argc -= optind;
 116         argv += optind;
 117
 118         if (*argv) {
 119                 rval = 0;
 120                 do {
 121                         infp = fopen(infile = *argv, "r");
 122                         if (infp == NULL) {
 123                                 warn("%s", *argv);
 124                                 rval = 1;
 125                                 continue;
 126                         }
 127                         rval |= decode();
 128                         fclose(infp);
 129                 } while (*++argv);
 130         } else {
 131                 infile = "stdin";
 132                 infp = stdin;
 133                 rval = decode();
 134         }
 135         exit(rval);
 136 }
 137
 138 static int
 139 decode(void)
 140 {
 141         int r, v;
 142
 143         if (rflag) {
 144                 /* relaxed alternative to decode2() */
 145                 outfile = "/dev/stdout";
 146                 outfp = stdout;
 147                 if (base64)
 148                         return (base64_decode());
 149                 else
 150                         return (uu_decode());
 151         }
 152         v = decode2();
 153         if (v == EOF) {
 154                 warnx("%s: missing or bad \"begin\" line", infile);
 155                 return (1);
 156         }
 157         for (r = v; cflag; r |= v) {
 158                 v = decode2();
 159                 if (v == EOF)
 160                         break;
 161         }
 162         return (r);
 163 }
 164
 165 static int
 166 decode2(void)
 167 {
 168         int flags, fd;
 169         size_t n, m;
 170         char *p, *q;
 171         void *handle;
 172         mode_t mode;
 173         struct passwd *pw;
 174         struct stat st;
 175         char buf[MAXPATHLEN+1];
 176
 177         base64 = 0;
 178         /* search for header line */
 179         for (;;) {
 180                 if (fgets(buf, sizeof(buf), infp) == NULL)
 181                         return (EOF);
 182                 p = buf;
 183                 if (strncmp(p, "begin-base64 ", 13) == 0) {
 184                         base64 = 1;
 185                         p += 13;
 186                 } else if (strncmp(p, "begin ", 6) == 0)
 187                         p += 6;
 188                 else
 189                         continue;
 190                 /* p points to mode */
 191                 q = strchr(p, ' ');
 192                 if (q == NULL)
 193                         continue;
 194                 *q++ = '\0';
 195                 /* q points to filename */
 196                 n = strlen(q);
 197                 while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
 198                         q[--n] = '\0';
 199                 /* found valid header? */
 200                 if (n > 0)
 201                         break;
 202         }
 203
 204         errno = 0;
 205         if ((handle = setmode(p)) == NULL) {
 206                 if (!errno)
 207                         warnx("invalid file mode: %s", infile);
 208                 else
 209                         warn("setmode malloc failed: %s", infile);
 210
 211                 return(1);
 212         }
 213
 214         mode = getmode(handle, 0) & 0666;
 215         free(handle);
 216
 217         if (sflag) {
 218                 /* don't strip, so try ~user/file expansion */
 219                 p = NULL;
 220                 pw = NULL;
 221                 if (*q == '~')
 222                         p = strchr(q, '/');
 223                 if (p != NULL) {
 224                         *p = '\0';
 225                         pw = getpwnam(q + 1);
 226                         *p = '/';
 227                 }
 228                 if (pw != NULL) {
 229                         n = strlen(pw->pw_dir);
 230                         if (buf + n > p) {
 231                                 /* make room */
 232                                 m = strlen(p);
 233                                 if (sizeof(buf) < n + m) {
 234                                         warnx("%s: bad output filename",
 235                                             infile);
 236                                         return (1);
 237                                 }
 238                                 p = memmove(buf + n, p, m);
 239                         }
 240                         q = memcpy(p - n, pw->pw_dir, n);
 241                 }
 242         } else {
 243                 /* strip down to leaf name */
 244                 p = strrchr(q, '/');
 245                 if (p != NULL)
 246                         q = p + 1;
 247         }
 248         if (!oflag)
 249                 outfile = q;
 250
 251         /* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
 252         if (pflag || strcmp(outfile, "/dev/stdout") == 0)
 253                 outfp = stdout;
 254         else {
 255                 flags = O_WRONLY|O_CREAT|O_EXCL;
 256                 if (lstat(outfile, &st) == 0) {
 257                         if (iflag) {
 258                                 warnc(EEXIST, "%s: %s", infile, outfile);
 259                                 return (0);
 260                         }
 261                         switch (st.st_mode & S_IFMT) {
 262                         case S_IFREG:
 263                         case S_IFLNK:
 264                                 /* avoid symlink attacks */
 265                                 if (unlink(outfile) == 0 || errno == ENOENT)
 266                                         break;
 267                                 warn("%s: unlink %s", infile, outfile);
 268                                 return (1);
 269                         case S_IFDIR:
 270                                 warnc(EISDIR, "%s: %s", infile, outfile);
 271                                 return (1);
 272                         default:
 273                                 if (oflag) {
 274                                         /* trust command-line names */
 275                                         flags &= ~O_EXCL;
 276                                         break;
 277                                 }
 278                                 warnc(EEXIST, "%s: %s", infile, outfile);
 279                                 return (1);
 280                         }
 281                 } else if (errno != ENOENT) {
 282                         warn("%s: %s", infile, outfile);
 283                         return (1);
 284                 }
 285                 if ((fd = open(outfile, flags, mode)) < 0 ||
 286                     (outfp = fdopen(fd, "w")) == NULL) {
 287                         warn("%s: %s", infile, outfile);
 288                         return (1);
 289                 }
 290         }
 291
 292         if (base64)
 293                 return (base64_decode());
 294         else
 295                 return (uu_decode());
 296 }
 297
 298 static int
 299 getline(char *buf, size_t size)
 300 {
 301         if (fgets(buf, size, infp) != NULL)
 302                 return (2);
 303         if (rflag)
 304                 return (0);
 305         warnx("%s: %s: short file", infile, outfile);
 306         return (1);
 307 }
 308
 309 static int
 310 checkend(const char *ptr, const char *end, const char *msg)
 311 {
 312         size_t n;
 313
 314         n = strlen(end);
 315         if (strncmp(ptr, end, n) != 0 ||
 316             strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
 317                 warnx("%s: %s: %s", infile, outfile, msg);
 318                 return (1);
 319         }
 320         if (fclose(outfp) != 0) {
 321                 warn("%s: %s", infile, outfile);
 322                 return (1);
 323         }
 324         return (0);
 325 }
 326
 327 static int
 328 uu_decode(void)
 329 {
 330         int i, ch;
 331         char *p;
 332         char buf[MAXPATHLEN+1];
 333
 334         /* for each input line */
 335         for (;;) {
 336                 switch (getline(buf, sizeof(buf))) {
 337                 case 0: return (0);
 338                 case 1: return (1);
 339                 }
 340
 341 #define DEC(c)  (((c) - ' ') & 077)             /* single character decode */
 342 #define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
 343
 344 #define OUT_OF_RANGE do {                                               \
 345         warnx("%s: %s: character out of range: [%d-%d]",                \
 346             infile, outfile, 1 + ' ', 077 + ' ' + 1);                   \
 347         return (1);                                                     \
 348 } while (0)
 349
 350                 /*
 351                  * `i' is used to avoid writing out all the characters
 352                  * at the end of the file.
 353                  */
 354                 p = buf;
 355                 if ((i = DEC(*p)) <= 0)
 356                         break;
 357                 for (++p; i > 0; p += 4, i -= 3)
 358                         if (i >= 3) {
 359                                 if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
 360                                      IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
 361                                         OUT_OF_RANGE;
 362
 363                                 ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
 364                                 putc(ch, outfp);
 365                                 ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
 366                                 putc(ch, outfp);
 367                                 ch = DEC(p[2]) << 6 | DEC(p[3]);
 368                                 putc(ch, outfp);
 369                         }
 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 (getline(buf, sizeof(buf))) {
 395         case 0:  return (0);
 396         case 1:  return (1);
 397         default: return (checkend(buf, "end", "no \"end\" line"));
 398         }
 399 }
 400
 401 static int
 402 base64_decode(void)
 403 {
 404         int n;
 405         char inbuf[MAXPATHLEN+1];
 406         unsigned char outbuf[MAXPATHLEN * 4];
 407
 408         for (;;) {
 409                 switch (getline(inbuf, sizeof(inbuf))) {
 410                 case 0: return (0);
 411                 case 1: return (1);
 412                 }
 413                 n = b64_pton(inbuf, outbuf, sizeof(outbuf));
 414                 if (n < 0)
 415                         break;
 416                 fwrite(outbuf, 1, n, outfp);
 417         }
 418         return (checkend(inbuf, "====",
 419                     "error decoding base64 input stream"));
 420 }
 421
 422 static void
 423 usage(void)
 424 {
 425         (void)fprintf(stderr,
 426 "usage: uudecode [-cimprs] [file ...]\n"
 427 "       uudecode [-i] -o output_file [file]\n"
 428 "       b64decode [-cimprs] [file ...]\n"
 429 "       b64decode [-i] -o output_file [file]\n");
 430         exit(1);
 431 }