uudecode.c revision 114594 
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. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if 0
35#ifndef lint
36static const char copyright[] =
37"@(#) Copyright (c) 1983, 1993\n\
38	The Regents of the University of California.  All rights reserved.\n";
39#endif /* not lint */
40
41#ifndef lint
42static char sccsid[] = "@(#)uudecode.c	8.2 (Berkeley) 4/2/94";
43#endif /* not lint */
44#endif
45#include <sys/cdefs.h>
46__FBSDID("$FreeBSD: head/usr.bin/uudecode/uudecode.c 114594 2003-05-03 19:44:46Z obrien $");
47
48/*
49 * uudecode [file ...]
50 *
51 * create the specified file, decoding as you go.
52 * used with uuencode.
53 */
54#include <sys/param.h>
55#include <sys/socket.h>
56#include <sys/stat.h>
57
58#include <netinet/in.h>
59
60#include <err.h>
61#include <errno.h>
62#include <fcntl.h>
63#include <libgen.h>
64#include <pwd.h>
65#include <resolv.h>
66#include <stdio.h>
67#include <stdlib.h>
68#include <string.h>
69#include <unistd.h>
70
71static const char *infile, *outfile;
72static FILE *infp, *outfp;
73static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
74
75static void	usage(void);
76static int	decode(void);
77static int	decode2(void);
78static int	uu_decode(void);
79static int	base64_decode(void);
80
81int
82main(int argc, char *argv[])
83{
84	int rval, ch;
85
86	if (strcmp(basename(argv[0]), "b64decode") == 0)
87		base64 = 1;
88
89	while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
90		switch(ch) {
91		case 'c':
92			if (oflag || rflag)
93				usage();
94			cflag = 1; /* multiple uudecode'd files */
95			break;
96		case 'i':
97			iflag = 1; /* ask before override files */
98			break;
99		case 'm':
100			base64 = 1;
101			break;
102		case 'o':
103			if (cflag || pflag || rflag || sflag)
104				usage();
105			oflag = 1; /* output to the specified file */
106			sflag = 1; /* do not strip pathnames for output */
107			outfile = optarg; /* set the output filename */
108			break;
109		case 'p':
110			if (oflag)
111				usage();
112			pflag = 1; /* print output to stdout */
113			break;
114		case 'r':
115			if (cflag || oflag)
116				usage();
117			rflag = 1; /* decode raw data */
118			break;
119		case 's':
120			if (oflag)
121				usage();
122			sflag = 1; /* do not strip pathnames for output */
123			break;
124		default:
125			usage();
126		}
127	}
128        argc -= optind;
129        argv += optind;
130
131	if (*argv) {
132		rval = 0;
133		do {
134			infp = fopen(infile = *argv, "r");
135			if (infp == NULL) {
136				warn("%s", *argv);
137				rval = 1;
138				continue;
139			}
140			rval |= decode();
141			fclose(infp);
142		} while (*++argv);
143	} else {
144		infile = "stdin";
145		infp = stdin;
146		rval = decode();
147	}
148	exit(rval);
149}
150
151static int
152decode(void)
153{
154	int r, v;
155
156	if (rflag) {
157		/* relaxed alternative to decode2() */
158		outfile = "/dev/stdout";
159		outfp = stdout;
160		if (base64)
161			return (base64_decode());
162		else
163			return (uu_decode());
164	}
165	v = decode2();
166	if (v == EOF) {
167		warnx("%s: missing or bad \"begin\" line", infile);
168		return (1);
169	}
170	for (r = v; cflag; r |= v) {
171		v = decode2();
172		if (v == EOF)
173			break;
174	}
175	return (r);
176}
177
178static int
179decode2(void)
180{
181	int flags, fd, mode;
182	size_t n, m;
183	char *p, *q;
184	void *handle;
185	struct passwd *pw;
186	struct stat st;
187	char buf[MAXPATHLEN+1];
188
189	base64 = 0;
190	/* search for header line */
191	for (;;) {
192		if (fgets(buf, sizeof(buf), infp) == NULL)
193			return (EOF);
194		p = buf;
195		if (strncmp(p, "begin-base64 ", 13) == 0) {
196			base64 = 1;
197			p += 13;
198		} else if (strncmp(p, "begin ", 6) == 0)
199			p += 6;
200		else
201			continue;
202		/* p points to mode */
203		q = strchr(p, ' ');
204		if (q == NULL)
205			continue;
206		*q++ = '\0';
207		/* q points to filename */
208		n = strlen(q);
209		while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
210			q[--n] = '\0';
211		/* found valid header? */
212		if (n > 0)
213			break;
214	}
215
216	handle = setmode(p);
217	if (handle == NULL) {
218		warnx("%s: unable to parse file mode", infile);
219		return (1);
220	}
221	mode = getmode(handle, 0) & 0666;
222	free(handle);
223
224	if (sflag) {
225		/* don't strip, so try ~user/file expansion */
226		p = NULL;
227		pw = NULL;
228		if (*q == '~')
229			p = strchr(q, '/');
230		if (p != NULL) {
231			*p = '\0';
232			pw = getpwnam(q + 1);
233			*p = '/';
234		}
235		if (pw != NULL) {
236			n = strlen(pw->pw_dir);
237			if (buf + n > p) {
238				/* make room */
239				m = strlen(p);
240				if (sizeof(buf) < n + m) {
241					warnx("%s: bad output filename",
242					    infile);
243					return (1);
244				}
245				p = memmove(buf + n, p, m);
246			}
247			q = memcpy(p - n, pw->pw_dir, n);
248		}
249	} else {
250		/* strip down to leaf name */
251		p = strrchr(q, '/');
252		if (p != NULL)
253			q = p + 1;
254	}
255	if (!oflag)
256		outfile = q;
257
258	/* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
259	if (pflag || strcmp(outfile, "/dev/stdout") == 0)
260		outfp = stdout;
261	else {
262		flags = O_WRONLY|O_CREAT|O_EXCL;
263		if (lstat(outfile, &st) == 0) {
264			if (iflag) {
265				warnc(EEXIST, "%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				warnc(EISDIR, "%s: %s", infile, outfile);
278				return (1);
279			default:
280				if (oflag) {
281					/* trust command-line names */
282					flags &= ~O_EXCL;
283					break;
284				}
285				warnc(EEXIST, "%s: %s", infile, outfile);
286				return (1);
287			}
288		} else if (errno != ENOENT) {
289			warn("%s: %s", infile, outfile);
290			return (1);
291		}
292		if ((fd = open(outfile, flags, mode)) < 0 ||
293		    (outfp = fdopen(fd, "w")) == NULL) {
294			warn("%s: %s", infile, outfile);
295			return (1);
296		}
297	}
298
299	if (base64)
300		return (base64_decode());
301	else
302		return (uu_decode());
303}
304
305static int
306getline(char *buf, size_t size)
307{
308	if (fgets(buf, size, infp) != NULL)
309		return (2);
310	if (rflag)
311		return (0);
312	warnx("%s: %s: short file", infile, outfile);
313	return (1);
314}
315
316static int
317checkend(const char *ptr, const char *end, const char *msg)
318{
319	size_t n;
320
321	n = strlen(end);
322	if (strncmp(ptr, end, n) != 0 ||
323	    strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
324		warnx("%s: %s: %s", infile, outfile, msg);
325		return (1);
326	}
327	if (fclose(outfp) != 0) {
328		warn("%s: %s", infile, outfile);
329		return (1);
330	}
331	return (0);
332}
333
334static int
335uu_decode(void)
336{
337	int i, ch;
338	char *p;
339	char buf[MAXPATHLEN+1];
340
341	/* for each input line */
342	for (;;) {
343		switch (getline(buf, sizeof(buf))) {
344		case 0: return (0);
345		case 1: return (1);
346		}
347
348#define	DEC(c)	(((c) - ' ') & 077)		/* single character decode */
349#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
350
351#define OUT_OF_RANGE do {						\
352	warnx("%s: %s: character out of range: [%d-%d]",		\
353	    infile, outfile, 1 + ' ', 077 + ' ' + 1);			\
354        return (1);							\
355} while (0)
356
357		/*
358		 * `i' is used to avoid writing out all the characters
359		 * at the end of the file.
360		 */
361		p = buf;
362		if ((i = DEC(*p)) <= 0)
363			break;
364		for (++p; i > 0; p += 4, i -= 3)
365			if (i >= 3) {
366				if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
367				     IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
368                                	OUT_OF_RANGE;
369
370				ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
371				putc(ch, outfp);
372				ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
373				putc(ch, outfp);
374				ch = DEC(p[2]) << 6 | DEC(p[3]);
375				putc(ch, outfp);
376			}
377			else {
378				if (i >= 1) {
379					if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
380	                                	OUT_OF_RANGE;
381					ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
382					putc(ch, outfp);
383				}
384				if (i >= 2) {
385					if (!(IS_DEC(*(p + 1)) &&
386						IS_DEC(*(p + 2))))
387		                                OUT_OF_RANGE;
388
389					ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
390					putc(ch, outfp);
391				}
392				if (i >= 3) {
393					if (!(IS_DEC(*(p + 2)) &&
394						IS_DEC(*(p + 3))))
395		                                OUT_OF_RANGE;
396					ch = DEC(p[2]) << 6 | DEC(p[3]);
397					putc(ch, outfp);
398				}
399			}
400	}
401	switch (getline(buf, sizeof(buf))) {
402	case 0:  return (0);
403	case 1:  return (1);
404	default: return (checkend(buf, "end", "no \"end\" line"));
405	}
406}
407
408static int
409base64_decode(void)
410{
411	int n;
412	char inbuf[MAXPATHLEN+1];
413	unsigned char outbuf[MAXPATHLEN * 4];
414
415	for (;;) {
416		switch (getline(inbuf, sizeof(inbuf))) {
417		case 0: return (0);
418		case 1: return (1);
419		}
420		n = b64_pton(inbuf, outbuf, sizeof(outbuf));
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
429static void
430usage(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}
439