uudecode.c revision 1.16 
1/*	$OpenBSD: uudecode.c,v 1.16 2008/07/29 18:25:28 sobrado Exp $	*/
2/*	$FreeBSD: uudecode.c,v 1.49 2003/05/03 19:44:46 obrien Exp $	*/
3
4/*-
5 * Copyright (c) 1983, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34static const char copyright[] =
35"@(#) Copyright (c) 1983, 1993\n\
36	The Regents of the University of California.  All rights reserved.\n";
37#endif /* not lint */
38
39#ifndef lint
40#if 0
41static const char sccsid[] = "@(#)uudecode.c	8.2 (Berkeley) 4/2/94";
42#endif
43static const char rcsid[] = "$OpenBSD: uudecode.c,v 1.16 2008/07/29 18:25:28 sobrado Exp $";
44#endif /* not lint */
45
46/*
47 * Create the specified file, decoding as you go.
48 * Used with uuencode.
49 */
50
51#include <sys/param.h>
52#include <sys/socket.h>
53#include <sys/stat.h>
54
55#include <netinet/in.h>
56
57#include <err.h>
58#include <errno.h>
59#include <fcntl.h>
60#include <locale.h>
61#include <pwd.h>
62#include <resolv.h>
63#include <stdio.h>
64#include <stdlib.h>
65#include <string.h>
66#include <unistd.h>
67
68static const char *infile, *outfile;
69static FILE *infp, *outfp;
70static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
71
72static void	usage(void);
73static int	decode(void);
74static int	decode2(void);
75static int	uu_decode(void);
76static int	base64_decode(void);
77
78enum program_mode {
79	MODE_DECODE,
80	MODE_B64DECODE
81} pmode;
82
83int
84main(int argc, char *argv[])
85{
86	int rval, ch;
87	extern char *__progname;
88	static const char *optstr[2] = {
89		"cimo:prs",
90		"cio:prs"
91	};
92
93	pmode = MODE_DECODE;
94	if (strcmp(__progname, "b64decode") == 0) {
95		base64 = 1;
96		pmode = MODE_B64DECODE;
97	}
98
99	setlocale(LC_ALL, "");
100	while ((ch = getopt(argc, argv, optstr[pmode])) != -1) {
101		switch(ch) {
102		case 'c':
103			if (oflag || rflag)
104				usage();
105			cflag = 1; /* multiple uudecode'd files */
106			break;
107		case 'i':
108			iflag = 1; /* ask before override files */
109			break;
110		case 'm':
111			base64 = 1;
112			break;
113		case 'o':
114			if (cflag || pflag || rflag || sflag)
115				usage();
116			oflag = 1; /* output to the specified file */
117			sflag = 1; /* do not strip pathnames for output */
118			outfile = optarg; /* set the output filename */
119			break;
120		case 'p':
121			if (oflag)
122				usage();
123			pflag = 1; /* print output to stdout */
124			break;
125		case 'r':
126			if (cflag || oflag)
127				usage();
128			rflag = 1; /* decode raw data */
129			break;
130		case 's':
131			if (oflag)
132				usage();
133			sflag = 1; /* do not strip pathnames for output */
134			break;
135		default:
136			usage();
137		}
138	}
139	argc -= optind;
140	argv += optind;
141
142	if (*argv) {
143		rval = 0;
144		do {
145			infp = fopen(infile = *argv, "r");
146			if (infp == NULL) {
147				warn("%s", *argv);
148				rval = 1;
149				continue;
150			}
151			rval |= decode();
152			fclose(infp);
153		} while (*++argv);
154	} else {
155		infile = "stdin";
156		infp = stdin;
157		rval = decode();
158	}
159	exit(rval);
160}
161
162static int
163decode(void)
164{
165	int r, v;
166
167	if (rflag) {
168		/* relaxed alternative to decode2() */
169		outfile = "/dev/stdout";
170		outfp = stdout;
171		if (base64)
172			return (base64_decode());
173		else
174			return (uu_decode());
175	}
176	v = decode2();
177	if (v == EOF) {
178		warnx("%s: missing or bad \"begin\" line", infile);
179		return (1);
180	}
181	for (r = v; cflag; r |= v) {
182		v = decode2();
183		if (v == EOF)
184			break;
185	}
186	return (r);
187}
188
189static int
190decode2(void)
191{
192	int flags, fd, mode;
193	size_t n, m;
194	char *p, *q;
195	void *handle;
196	struct passwd *pw;
197	struct stat st;
198	char buf[MAXPATHLEN];
199
200	base64 = 0;
201	/* search for header line */
202	for (;;) {
203		if (fgets(buf, sizeof(buf), infp) == NULL)
204			return (EOF);
205		p = buf;
206		if (strncmp(p, "begin-base64 ", 13) == 0) {
207			base64 = 1;
208			p += 13;
209		} else if (strncmp(p, "begin ", 6) == 0)
210			p += 6;
211		else
212			continue;
213		/* p points to mode */
214		q = strchr(p, ' ');
215		if (q == NULL)
216			continue;
217		*q++ = '\0';
218		/* q points to filename */
219		n = strlen(q);
220		while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
221			q[--n] = '\0';
222		/* found valid header? */
223		if (n > 0)
224			break;
225	}
226
227	handle = setmode(p);
228	if (handle == NULL) {
229		warnx("%s: unable to parse file mode", infile);
230		return (1);
231	}
232	mode = getmode(handle, 0) & 0666;
233	free(handle);
234
235	if (sflag) {
236		/* don't strip, so try ~user/file expansion */
237		p = NULL;
238		pw = NULL;
239		if (*q == '~')
240			p = strchr(q, '/');
241		if (p != NULL) {
242			*p = '\0';
243			pw = getpwnam(q + 1);
244			*p = '/';
245		}
246		if (pw != NULL) {
247			n = strlen(pw->pw_dir);
248			if (buf + n > p) {
249				/* make room */
250				m = strlen(p);
251				if (sizeof(buf) < n + m) {
252					warnx("%s: bad output filename",
253					    infile);
254					return (1);
255				}
256				p = memmove(buf + n, p, m);
257			}
258			q = memcpy(p - n, pw->pw_dir, n);
259		}
260	} else {
261		/* strip down to leaf name */
262		p = strrchr(q, '/');
263		if (p != NULL)
264			q = p + 1;
265	}
266	if (!oflag)
267		outfile = q;
268
269	/* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
270	if (pflag || strcmp(outfile, "/dev/stdout") == 0)
271		outfp = stdout;
272	else {
273		flags = O_WRONLY|O_CREAT|O_EXCL|O_NOFOLLOW;
274		if (lstat(outfile, &st) == 0) {
275			if (iflag) {
276				errno = EEXIST;
277				warn("%s: %s", infile, outfile);
278				return (0);
279			}
280			switch (st.st_mode & S_IFMT) {
281			case S_IFREG:
282			case S_IFLNK:
283				/* avoid symlink attacks */
284				if (unlink(outfile) == 0 || errno == ENOENT)
285					break;
286				warn("%s: unlink %s", infile, outfile);
287				return (1);
288			case S_IFDIR:
289				errno = EISDIR;
290				warn("%s: %s", infile, outfile);
291				return (1);
292			default:
293				if (oflag) {
294					/* trust command-line names */
295					flags &= ~(O_EXCL|O_NOFOLLOW);
296					break;
297				}
298				errno = EEXIST;
299				warn("%s: %s", infile, outfile);
300				return (1);
301			}
302		} else if (errno != ENOENT) {
303			warn("%s: %s", infile, outfile);
304			return (1);
305		}
306		if ((fd = open(outfile, flags, mode)) < 0 ||
307		    (outfp = fdopen(fd, "w")) == NULL) {
308			warn("%s: %s", infile, outfile);
309			return (1);
310		}
311	}
312
313	if (base64)
314		return (base64_decode());
315	else
316		return (uu_decode());
317}
318
319static int
320getline(char *buf, size_t size)
321{
322	if (fgets(buf, size, infp) != NULL)
323		return (2);
324	if (rflag)
325		return (0);
326	warnx("%s: %s: short file", infile, outfile);
327	return (1);
328}
329
330static int
331checkend(const char *ptr, const char *end, const char *msg)
332{
333	size_t n;
334
335	n = strlen(end);
336	if (strncmp(ptr, end, n) != 0 ||
337	    strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
338		warnx("%s: %s: %s", infile, outfile, msg);
339		return (1);
340	}
341	if (fclose(outfp) != 0) {
342		warn("%s: %s", infile, outfile);
343		return (1);
344	}
345	return (0);
346}
347
348static int
349uu_decode(void)
350{
351	int i, ch;
352	char *p;
353	char buf[MAXPATHLEN];
354
355	/* for each input line */
356	for (;;) {
357		switch (getline(buf, sizeof(buf))) {
358		case 0:
359			return (0);
360		case 1:
361			return (1);
362		}
363
364#define	DEC(c)	(((c) - ' ') & 077)		/* single character decode */
365#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
366
367#define OUT_OF_RANGE do {						\
368	warnx("%s: %s: character out of range: [%d-%d]",		\
369	    infile, outfile, 1 + ' ', 077 + ' ' + 1);			\
370	return (1);							\
371} while (0)
372
373		/*
374		 * `i' is used to avoid writing out all the characters
375		 * at the end of the file.
376		 */
377		p = buf;
378		if ((i = DEC(*p)) <= 0)
379			break;
380		for (++p; i > 0; p += 4, i -= 3)
381			if (i >= 3) {
382				if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
383				     IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
384					OUT_OF_RANGE;
385
386				ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
387				putc(ch, outfp);
388				ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
389				putc(ch, outfp);
390				ch = DEC(p[2]) << 6 | DEC(p[3]);
391				putc(ch, outfp);
392			}
393			else {
394				if (i >= 1) {
395					if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
396						OUT_OF_RANGE;
397					ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
398					putc(ch, outfp);
399				}
400				if (i >= 2) {
401					if (!(IS_DEC(*(p + 1)) &&
402					    IS_DEC(*(p + 2))))
403						OUT_OF_RANGE;
404
405					ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
406					putc(ch, outfp);
407				}
408				if (i >= 3) {
409					if (!(IS_DEC(*(p + 2)) &&
410					    IS_DEC(*(p + 3))))
411						OUT_OF_RANGE;
412					ch = DEC(p[2]) << 6 | DEC(p[3]);
413					putc(ch, outfp);
414				}
415			}
416	}
417	switch (getline(buf, sizeof(buf))) {
418	case 0:
419		return (0);
420	case 1:
421		return (1);
422	default:
423		return (checkend(buf, "end", "no \"end\" line"));
424	}
425}
426
427static int
428base64_decode(void)
429{
430	int n;
431	char inbuf[MAXPATHLEN];
432	unsigned char outbuf[MAXPATHLEN * 4];
433
434	for (;;) {
435		switch (getline(inbuf, sizeof(inbuf))) {
436		case 0:
437			return (0);
438		case 1:
439			return (1);
440		}
441		n = b64_pton(inbuf, outbuf, sizeof(outbuf));
442		if (n < 0)
443			break;
444		fwrite(outbuf, 1, n, outfp);
445	}
446	return (checkend(inbuf, "====",
447		    "error decoding base64 input stream"));
448}
449
450static void
451usage(void)
452{
453	switch (pmode) {
454	case MODE_DECODE:
455		(void)fprintf(stderr,
456		    "usage: uudecode [-cimprs] [file ...]\n"
457		    "       uudecode [-i] -o output_file [file]\n");
458		break;
459	case MODE_B64DECODE:
460		(void)fprintf(stderr,
461		    "usage: b64decode [-ciprs] [file ...]\n"
462		    "       b64decode [-i] -o output_file [file]\n");
463		break;
464	}
465	exit(1);
466}
467