uudecode.c revision 1.14 
1/*	$OpenBSD: uudecode.c,v 1.14 2004/04/09 22:54:02 millert 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 1.14 2004/04/09 22:54:02 millert 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
78int
79main(int argc, char *argv[])
80{
81	int rval, ch;
82	extern char *__progname;
83
84	if (strcmp(__progname, "b64decode") == 0)
85		base64 = 1;
86
87	setlocale(LC_ALL, "");
88	while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
89		switch(ch) {
90		case 'c':
91			if (oflag || rflag)
92				usage();
93			cflag = 1; /* multiple uudecode'd files */
94			break;
95		case 'i':
96			iflag = 1; /* ask before override files */
97			break;
98		case 'm':
99			base64 = 1;
100			break;
101		case 'o':
102			if (cflag || pflag || rflag || sflag)
103				usage();
104			oflag = 1; /* output to the specified file */
105			sflag = 1; /* do not strip pathnames for output */
106			outfile = optarg; /* set the output filename */
107			break;
108		case 'p':
109			if (oflag)
110				usage();
111			pflag = 1; /* print output to stdout */
112			break;
113		case 'r':
114			if (cflag || oflag)
115				usage();
116			rflag = 1; /* decode raw data */
117			break;
118		case 's':
119			if (oflag)
120				usage();
121			sflag = 1; /* do not strip pathnames for output */
122			break;
123		default:
124			usage();
125		}
126	}
127	argc -= optind;
128	argv += optind;
129
130	if (*argv) {
131		rval = 0;
132		do {
133			infp = fopen(infile = *argv, "r");
134			if (infp == NULL) {
135				warn("%s", *argv);
136				rval = 1;
137				continue;
138			}
139			rval |= decode();
140			fclose(infp);
141		} while (*++argv);
142	} else {
143		infile = "stdin";
144		infp = stdin;
145		rval = decode();
146	}
147	exit(rval);
148}
149
150static int
151decode(void)
152{
153	int r, v;
154
155	if (rflag) {
156		/* relaxed alternative to decode2() */
157		outfile = "/dev/stdout";
158		outfp = stdout;
159		if (base64)
160			return (base64_decode());
161		else
162			return (uu_decode());
163	}
164	v = decode2();
165	if (v == EOF) {
166		warnx("%s: missing or bad \"begin\" line", infile);
167		return (1);
168	}
169	for (r = v; cflag; r |= v) {
170		v = decode2();
171		if (v == EOF)
172			break;
173	}
174	return (r);
175}
176
177static int
178decode2(void)
179{
180	int flags, fd, mode;
181	size_t n, m;
182	char *p, *q;
183	void *handle;
184	struct passwd *pw;
185	struct stat st;
186	char buf[MAXPATHLEN];
187
188	base64 = 0;
189	/* search for header line */
190	for (;;) {
191		if (fgets(buf, sizeof(buf), infp) == NULL)
192			return (EOF);
193		p = buf;
194		if (strncmp(p, "begin-base64 ", 13) == 0) {
195			base64 = 1;
196			p += 13;
197		} else if (strncmp(p, "begin ", 6) == 0)
198			p += 6;
199		else
200			continue;
201		/* p points to mode */
202		q = strchr(p, ' ');
203		if (q == NULL)
204			continue;
205		*q++ = '\0';
206		/* q points to filename */
207		n = strlen(q);
208		while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
209			q[--n] = '\0';
210		/* found valid header? */
211		if (n > 0)
212			break;
213	}
214
215	handle = setmode(p);
216	if (handle == NULL) {
217		warnx("%s: unable to parse file mode", infile);
218		return (1);
219	}
220	mode = getmode(handle, 0) & 0666;
221	free(handle);
222
223	if (sflag) {
224		/* don't strip, so try ~user/file expansion */
225		p = NULL;
226		pw = NULL;
227		if (*q == '~')
228			p = strchr(q, '/');
229		if (p != NULL) {
230			*p = '\0';
231			pw = getpwnam(q + 1);
232			*p = '/';
233		}
234		if (pw != NULL) {
235			n = strlen(pw->pw_dir);
236			if (buf + n > p) {
237				/* make room */
238				m = strlen(p);
239				if (sizeof(buf) < n + m) {
240					warnx("%s: bad output filename",
241					    infile);
242					return (1);
243				}
244				p = memmove(buf + n, p, m);
245			}
246			q = memcpy(p - n, pw->pw_dir, n);
247		}
248	} else {
249		/* strip down to leaf name */
250		p = strrchr(q, '/');
251		if (p != NULL)
252			q = p + 1;
253	}
254	if (!oflag)
255		outfile = q;
256
257	/* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
258	if (pflag || strcmp(outfile, "/dev/stdout") == 0)
259		outfp = stdout;
260	else {
261		flags = O_WRONLY|O_CREAT|O_EXCL|O_NOFOLLOW;
262		if (lstat(outfile, &st) == 0) {
263			if (iflag) {
264				errno = EEXIST;
265				warn("%s: %s", infile, outfile);
266				return (0);
267			}
268			switch (st.st_mode & S_IFMT) {
269			case S_IFREG:
270			case S_IFLNK:
271				/* avoid symlink attacks */
272				if (unlink(outfile) == 0 || errno == ENOENT)
273					break;
274				warn("%s: unlink %s", infile, outfile);
275				return (1);
276			case S_IFDIR:
277				errno = EISDIR;
278				warn("%s: %s", infile, outfile);
279				return (1);
280			default:
281				if (oflag) {
282					/* trust command-line names */
283					flags &= ~(O_EXCL|O_NOFOLLOW);
284					break;
285				}
286				errno = EEXIST;
287				warn("%s: %s", infile, outfile);
288				return (1);
289			}
290		} else if (errno != ENOENT) {
291			warn("%s: %s", infile, outfile);
292			return (1);
293		}
294		if ((fd = open(outfile, flags, mode)) < 0 ||
295		    (outfp = fdopen(fd, "w")) == NULL) {
296			warn("%s: %s", infile, outfile);
297			return (1);
298		}
299	}
300
301	if (base64)
302		return (base64_decode());
303	else
304		return (uu_decode());
305}
306
307static int
308getline(char *buf, size_t size)
309{
310	if (fgets(buf, size, infp) != NULL)
311		return (2);
312	if (rflag)
313		return (0);
314	warnx("%s: %s: short file", infile, outfile);
315	return (1);
316}
317
318static int
319checkend(const char *ptr, const char *end, const char *msg)
320{
321	size_t n;
322
323	n = strlen(end);
324	if (strncmp(ptr, end, n) != 0 ||
325	    strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
326		warnx("%s: %s: %s", infile, outfile, msg);
327		return (1);
328	}
329	if (fclose(outfp) != 0) {
330		warn("%s: %s", infile, outfile);
331		return (1);
332	}
333	return (0);
334}
335
336static int
337uu_decode(void)
338{
339	int i, ch;
340	char *p;
341	char buf[MAXPATHLEN];
342
343	/* for each input line */
344	for (;;) {
345		switch (getline(buf, sizeof(buf))) {
346		case 0:
347			return (0);
348		case 1:
349			return (1);
350		}
351
352#define	DEC(c)	(((c) - ' ') & 077)		/* single character decode */
353#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
354
355#define OUT_OF_RANGE do {						\
356	warnx("%s: %s: character out of range: [%d-%d]",		\
357	    infile, outfile, 1 + ' ', 077 + ' ' + 1);			\
358	return (1);							\
359} while (0)
360
361		/*
362		 * `i' is used to avoid writing out all the characters
363		 * at the end of the file.
364		 */
365		p = buf;
366		if ((i = DEC(*p)) <= 0)
367			break;
368		for (++p; i > 0; p += 4, i -= 3)
369			if (i >= 3) {
370				if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
371				     IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
372					OUT_OF_RANGE;
373
374				ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
375				putc(ch, outfp);
376				ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
377				putc(ch, outfp);
378				ch = DEC(p[2]) << 6 | DEC(p[3]);
379				putc(ch, outfp);
380			}
381			else {
382				if (i >= 1) {
383					if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
384						OUT_OF_RANGE;
385					ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
386					putc(ch, outfp);
387				}
388				if (i >= 2) {
389					if (!(IS_DEC(*(p + 1)) &&
390					    IS_DEC(*(p + 2))))
391						OUT_OF_RANGE;
392
393					ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
394					putc(ch, outfp);
395				}
396				if (i >= 3) {
397					if (!(IS_DEC(*(p + 2)) &&
398					    IS_DEC(*(p + 3))))
399						OUT_OF_RANGE;
400					ch = DEC(p[2]) << 6 | DEC(p[3]);
401					putc(ch, outfp);
402				}
403			}
404	}
405	switch (getline(buf, sizeof(buf))) {
406	case 0:
407		return (0);
408	case 1:
409		return (1);
410	default:
411		return (checkend(buf, "end", "no \"end\" line"));
412	}
413}
414
415static int
416base64_decode(void)
417{
418	int n;
419	char inbuf[MAXPATHLEN];
420	unsigned char outbuf[MAXPATHLEN * 4];
421
422	for (;;) {
423		switch (getline(inbuf, sizeof(inbuf))) {
424		case 0:
425			return (0);
426		case 1:
427			return (1);
428		}
429		n = b64_pton(inbuf, outbuf, sizeof(outbuf));
430		if (n < 0)
431			break;
432		fwrite(outbuf, 1, n, outfp);
433	}
434	return (checkend(inbuf, "====",
435		    "error decoding base64 input stream"));
436}
437
438static void
439usage(void)
440{
441	(void)fprintf(stderr,
442	    "usage: uudecode [-cimprs] [file ...]\n"
443	    "       uudecode [-i] -o output_file [file]\n"
444	    "       b64decode [-cimprs] [file ...]\n"
445	    "       b64decode [-i] -o output_file [file]\n");
446	exit(1);
447}
448