uudecode.c revision 111596 
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#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1983, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#if 0
41#ifndef lint
42static char sccsid[] = "@(#)uudecode.c	8.2 (Berkeley) 4/2/94";
43#endif /* not lint */
44#endif
45
46#include <sys/cdefs.h>
47__FBSDID("$FreeBSD: head/usr.bin/uudecode/uudecode.c 111596 2003-02-27 05:59:18Z fanf $");
48
49/*
50 * uudecode [file ...]
51 *
52 * create the specified file, decoding as you go.
53 * used with uuencode.
54 */
55#include <sys/param.h>
56#include <sys/socket.h>
57#include <sys/stat.h>
58
59#include <netinet/in.h>
60
61#include <err.h>
62#include <errno.h>
63#include <fcntl.h>
64#include <libgen.h>
65#include <pwd.h>
66#include <resolv.h>
67#include <stdio.h>
68#include <stdlib.h>
69#include <string.h>
70#include <unistd.h>
71
72static const char *infile, *outfile;
73static FILE *infp, *outfp;
74static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
75
76static void	usage(void);
77static int	decode(void);
78static int	decode2(void);
79static int	uu_decode(void);
80static int	base64_decode(void);
81
82int
83main(int argc, char *argv[])
84{
85	int rval, ch;
86
87	if (strcmp(basename(argv[0]), "b64decode") == 0)
88		base64 = 1;
89
90	while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
91		switch(ch) {
92		case 'c':
93			if (oflag || rflag)
94				usage();
95			cflag = 1; /* multiple uudecode'd files */
96			break;
97		case 'i':
98			iflag = 1; /* ask before override files */
99			break;
100		case 'm':
101			base64 = 1;
102			break;
103		case 'o':
104			if (cflag || pflag || rflag || sflag)
105				usage();
106			oflag = 1; /* output to the specified file */
107			sflag = 1; /* do not strip pathnames for output */
108			outfile = optarg; /* set the output filename */
109			break;
110		case 'p':
111			if (oflag)
112				usage();
113			pflag = 1; /* print output to stdout */
114			break;
115		case 'r':
116			if (cflag || oflag)
117				usage();
118			rflag = 1; /* decode raw data */
119			break;
120		case 's':
121			if (oflag)
122				usage();
123			sflag = 1; /* do not strip pathnames for output */
124			break;
125		default:
126			usage();
127		}
128	}
129        argc -= optind;
130        argv += optind;
131
132	if (*argv) {
133		rval = 0;
134		do {
135			infp = fopen(infile = *argv, "r");
136			if (infp == NULL) {
137				warn("%s", *argv);
138				rval = 1;
139				continue;
140			}
141			rval |= decode();
142			fclose(infp);
143		} while (*++argv);
144	} else {
145		infile = "stdin";
146		infp = stdin;
147		rval = decode();
148	}
149	exit(rval);
150}
151
152static int
153decode(void)
154{
155	int r, v;
156
157	if (rflag) {
158		/* relaxed alternative to decode2() */
159		outfile = "/dev/stdout";
160		outfp = stdout;
161		if (base64)
162			return (base64_decode());
163		else
164			return (uu_decode());
165	}
166	v = decode2();
167	if (v == EOF) {
168		warnx("%s: missing or bad \"begin\" line", infile);
169		return (1);
170	}
171	for (r = v; cflag; r |= v) {
172		v = decode2();
173		if (v == EOF)
174			break;
175	}
176	return (r);
177}
178
179static int
180decode2(void)
181{
182	int flags, fd, mode;
183	size_t n, m;
184	char *p, *q;
185	void *handle;
186	struct passwd *pw;
187	struct stat st;
188	char buf[MAXPATHLEN+1];
189
190	base64 = 0;
191	/* search for header line */
192	for (;;) {
193		if (fgets(buf, sizeof(buf), infp) == NULL)
194			return (EOF);
195		p = buf;
196		if (strncmp(p, "begin-base64 ", 13) == 0) {
197			base64 = 1;
198			p += 13;
199		} else if (strncmp(p, "begin ", 6) == 0)
200			p += 6;
201		else
202			continue;
203		/* p points to mode */
204		q = strchr(p, ' ');
205		if (q == NULL)
206			continue;
207		*q++ = '\0';
208		/* q points to filename */
209		n = strlen(q);
210		while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
211			q[--n] = '\0';
212		/* found valid header? */
213		if (n > 0)
214			break;
215	}
216
217	handle = setmode(p);
218	if (handle == NULL) {
219		warnx("%s: unable to parse file mode", infile);
220		return (1);
221	}
222	mode = getmode(handle, 0) & 0666;
223	free(handle);
224
225	if (sflag) {
226		/* don't strip, so try ~user/file expansion */
227		p = NULL;
228		pw = NULL;
229		if (*q == '~')
230			p = strchr(q, '/');
231		if (p != NULL) {
232			*p = '\0';
233			pw = getpwnam(q + 1);
234			*p = '/';
235		}
236		if (pw != NULL) {
237			n = strlen(pw->pw_dir);
238			if (buf + n > p) {
239				/* make room */
240				m = strlen(p);
241				if (sizeof(buf) < n + m) {
242					warnx("%s: bad output filename",
243					    infile);
244					return (1);
245				}
246				p = memmove(buf + n, p, m);
247			}
248			q = memcpy(p - n, pw->pw_dir, n);
249		}
250	} else if (strcmp(q, "/dev/stdout") != 0) {
251		/* strip down to leaf name */
252		p = strrchr(q, '/');
253		if (p != NULL)
254			q = p + 1;
255	}
256	if (!oflag)
257		outfile = q;
258
259	/* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
260	if (pflag || strcmp(outfile, "/dev/stdout") == 0)
261		outfp = stdout;
262	else {
263		flags = O_WRONLY|O_CREAT|O_EXCL;
264		if (lstat(outfile, &st) == 0) {
265			if (iflag) {
266				warnc(EEXIST, "%s: %s", infile, outfile);
267				return (0);
268			}
269			switch (st.st_mode & S_IFMT) {
270			case S_IFREG:
271			case S_IFLNK:
272				/* avoid symlink attacks */
273				if (unlink(outfile) == 0 || errno == ENOENT)
274					break;
275				warn("%s: unlink %s", infile, outfile);
276				return (1);
277			case S_IFDIR:
278				warnc(EISDIR, "%s: %s", infile, outfile);
279				return (1);
280			default:
281				if (oflag) {
282					/* trust command-line names */
283					flags &= ~O_EXCL;
284					break;
285				}
286				warnc(EEXIST, "%s: %s", infile, outfile);
287				return (1);
288			}
289		} else if (errno != ENOENT) {
290			warn("%s: %s", infile, outfile);
291			return (1);
292		}
293		if ((fd = open(outfile, flags, mode)) < 0 ||
294		    (outfp = fdopen(fd, "w")) == NULL) {
295			warn("%s: %s", infile, outfile);
296			return (1);
297		}
298	}
299
300	if (base64)
301		return (base64_decode());
302	else
303		return (uu_decode());
304}
305
306static int
307getline(char *buf, size_t size)
308{
309	if (fgets(buf, size, infp) != NULL)
310		return (2);
311	if (!rflag)
312		return (0);
313	warnx("%s: %s: short file", infile, outfile);
314	return (1);
315}
316
317static int
318checkend(const char *ptr, const char *end, const char *msg)
319{
320	size_t n;
321
322	n = strlen(end);
323	if (strncmp(ptr, end, n) != 0 ||
324	    strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
325		warnx("%s: %s: %s", infile, outfile, msg);
326		return (1);
327	}
328	if (fclose(outfp) != 0) {
329		warn("%s: %s", infile, outfile);
330		return (1);
331	}
332	return (0);
333}
334
335static int
336uu_decode(void)
337{
338	int i, ch;
339	char *p;
340	char buf[MAXPATHLEN+1];
341
342	/* for each input line */
343	for (;;) {
344		switch (getline(buf, sizeof(buf))) {
345		case 0: return (0);
346		case 1: return (1);
347		}
348
349#define	DEC(c)	(((c) - ' ') & 077)		/* single character decode */
350#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
351
352#define OUT_OF_RANGE do {						\
353	warnx("%s: %s: character out of range: [%d-%d]",		\
354	    infile, outfile, 1 + ' ', 077 + ' ' + 1);			\
355        return (1);							\
356} while (0)
357
358		/*
359		 * `i' is used to avoid writing out all the characters
360		 * at the end of the file.
361		 */
362		p = buf;
363		if ((i = DEC(*p)) <= 0)
364			break;
365		for (++p; i > 0; p += 4, i -= 3)
366			if (i >= 3) {
367				if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
368				     IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
369                                	OUT_OF_RANGE;
370
371				ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
372				putc(ch, outfp);
373				ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
374				putc(ch, outfp);
375				ch = DEC(p[2]) << 6 | DEC(p[3]);
376				putc(ch, outfp);
377			}
378			else {
379				if (i >= 1) {
380					if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
381	                                	OUT_OF_RANGE;
382					ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
383					putc(ch, outfp);
384				}
385				if (i >= 2) {
386					if (!(IS_DEC(*(p + 1)) &&
387						IS_DEC(*(p + 2))))
388		                                OUT_OF_RANGE;
389
390					ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
391					putc(ch, outfp);
392				}
393				if (i >= 3) {
394					if (!(IS_DEC(*(p + 2)) &&
395						IS_DEC(*(p + 3))))
396		                                OUT_OF_RANGE;
397					ch = DEC(p[2]) << 6 | DEC(p[3]);
398					putc(ch, outfp);
399				}
400			}
401	}
402	switch (getline(buf, sizeof(buf))) {
403	case 0:  return (0);
404	case 1:  return (1);
405	default: return (checkend(buf, "end", "no \"end\" line"));
406	}
407}
408
409static int
410base64_decode(void)
411{
412	int n;
413	char inbuf[MAXPATHLEN+1];
414	unsigned char outbuf[MAXPATHLEN * 4];
415
416	for (;;) {
417		switch (getline(inbuf, sizeof(inbuf))) {
418		case 0: return (0);
419		case 1: return (1);
420		}
421		n = b64_pton(inbuf, outbuf, sizeof(outbuf));
422		if (n < 0)
423			break;
424		fwrite(outbuf, 1, n, outfp);
425	}
426	return (checkend(inbuf, "====",
427		    "error decoding base64 input stream"));
428}
429
430static void
431usage(void)
432{
433	(void)fprintf(stderr,
434"usage: uudecode [-cimprs] [file ...]\n"
435"       uudecode [-i] -o output_file [file]\n"
436"       b64decode [-cimprs] [file ...]\n"
437"       b64decode [-i] -o output_file [file]\n");
438	exit(1);
439}
440