crontab.c revision 4774:cdf5747c54d6 
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
26/*	  All Rights Reserved  	*/
27
28
29#pragma ident	"%Z%%M%	%I%	%E% SMI"
30
31#include <sys/types.h>
32#include <sys/stat.h>
33#include <sys/types.h>
34#include <sys/wait.h>
35#include <errno.h>
36#include <signal.h>
37#include <stdio.h>
38#include <stdlib.h>
39#include <string.h>
40#include <fcntl.h>
41#include <ctype.h>
42#include <pwd.h>
43#include <unistd.h>
44#include <locale.h>
45#include <nl_types.h>
46#include <langinfo.h>
47#include <libintl.h>
48#include <security/pam_appl.h>
49#include "cron.h"
50#include "getresponse.h"
51
52#if defined(XPG4)
53#define	VIPATH	"/usr/xpg4/bin/vi"
54#elif defined(XPG6)
55#define	VIPATH	"/usr/xpg6/bin/vi"
56#else
57#define	_XPG_NOTDEFINED
58#define	VIPATH	"vi"
59#endif
60
61#define	TMPFILE		"_cron"		/* prefix for tmp file */
62#define	CRMODE		0600	/* mode for creating crontabs */
63
64#define	BADCREATE	\
65	"can't create your crontab file in the crontab directory."
66#define	BADOPEN		"can't open your crontab file."
67#define	BADSHELL	\
68	"because your login shell isn't /usr/bin/sh, you can't use cron."
69#define	WARNSHELL	"warning: commands will be executed using /usr/bin/sh\n"
70#define	BADUSAGE	\
71	"usage:\n"			\
72	"\tcrontab [file]\n"		\
73	"\tcrontab -e [username]\n"	\
74	"\tcrontab -l [username]\n"	\
75	"\tcrontab -r [username]"
76#define	INVALIDUSER	"you are not a valid user (no entry in /etc/passwd)."
77#define	NOTALLOWED	"you are not authorized to use cron.  Sorry."
78#define	NOTROOT		\
79	"you must be super-user to access another user's crontab file"
80#define	AUDITREJECT	"The audit context for your shell has not been set."
81#define	EOLN		"unexpected end of line."
82#define	UNEXPECT	"unexpected character found in line."
83#define	OUTOFBOUND	"number out of bounds."
84#define	ERRSFND		"errors detected in input, no crontab file generated."
85#define	ED_ERROR	\
86	"     The editor indicates that an error occurred while you were\n"\
87	"     editing the crontab data - usually a minor typing error.\n\n"
88#define	BADREAD		"error reading your crontab file"
89#define	ED_PROMPT	\
90	"     Edit again, to ensure crontab information is intact (%s/%s)?\n"\
91	"     ('%s' will discard edits.)"
92#define	NAMETOOLONG	"login name too long"
93
94extern int	per_errno;
95
96extern int	audit_crontab_modify(char *, char *, int);
97extern int	audit_crontab_delete(char *, int);
98extern int	audit_crontab_not_allowed(uid_t, char *);
99
100int		err;
101int		cursor;
102char		*cf;
103char		*tnam;
104char		edtemp[5+13+1];
105char		line[CTLINESIZE];
106static		char	login[UNAMESIZE];
107
108static int	next_field(int, int);
109static void	catch(int);
110static void	crabort(char *);
111static void	cerror(char *);
112static void	copycron(FILE *);
113
114int
115main(int argc, char **argv)
116{
117	int	c, r;
118	int	rflag	= 0;
119	int	lflag	= 0;
120	int	eflag	= 0;
121	int	errflg	= 0;
122	char *pp;
123	FILE *fp, *tmpfp;
124	struct stat stbuf;
125	struct passwd *pwp;
126	time_t omodtime;
127	char *editor;
128	char buf[BUFSIZ];
129	uid_t ruid;
130	pid_t pid;
131	int stat_loc;
132	int ret;
133	char real_login[UNAMESIZE];
134	int tmpfd = -1;
135	pam_handle_t *pamh;
136	int pam_error;
137
138	(void) setlocale(LC_ALL, "");
139#if !defined(TEXT_DOMAIN)	/* Should be defined by cc -D */
140#define	TEXT_DOMAIN "SYS_TEST"	/* Use this only if it weren't */
141#endif
142	(void) textdomain(TEXT_DOMAIN);
143
144	if (init_yes() < 0) {
145		(void) fprintf(stderr, gettext(ERR_MSG_INIT_YES),
146		    strerror(errno));
147		exit(1);
148	}
149
150	while ((c = getopt(argc, argv, "elr")) != EOF)
151		switch (c) {
152			case 'e':
153				eflag++;
154				break;
155			case 'l':
156				lflag++;
157				break;
158			case 'r':
159				rflag++;
160				break;
161			case '?':
162				errflg++;
163				break;
164		}
165
166	if (eflag + lflag + rflag > 1)
167		errflg++;
168
169	argc -= optind;
170	argv += optind;
171	if (errflg || argc > 1)
172		crabort(BADUSAGE);
173
174	ruid = getuid();
175	if ((pwp = getpwuid(ruid)) == NULL)
176		crabort(INVALIDUSER);
177
178	if (strlcpy(real_login, pwp->pw_name, sizeof (real_login))
179	    >= sizeof (real_login))
180		crabort(NAMETOOLONG);
181
182	if ((eflag || lflag || rflag) && argc == 1) {
183		if ((pwp = getpwnam(*argv)) == NULL)
184			crabort(INVALIDUSER);
185
186		if (!chkauthattr(CRONADMIN_AUTH, real_login)) {
187			if (pwp->pw_uid != ruid)
188				crabort(NOTROOT);
189			else
190				pp = getuser(ruid);
191		} else
192			pp = *argv++;
193	} else {
194		pp = getuser(ruid);
195	}
196
197	if (pp == NULL) {
198		if (per_errno == 2)
199			crabort(BADSHELL);
200		else
201			crabort(INVALIDUSER);
202	}
203	if (strlcpy(login, pp, sizeof (login)) >= sizeof (login))
204		crabort(NAMETOOLONG);
205	if (!allowed(login, CRONALLOW, CRONDENY))
206		crabort(NOTALLOWED);
207
208	/* Do account validation check */
209	pam_error = pam_start("cron", pp, NULL, &pamh);
210	if (pam_error != PAM_SUCCESS) {
211		crabort((char *)pam_strerror(pamh, pam_error));
212	}
213	pam_error = pam_acct_mgmt(pamh, PAM_SILENT);
214	if (pam_error != PAM_SUCCESS) {
215		(void) fprintf(stderr, gettext("Warning - Invalid account: "
216		    "'%s' not allowed to execute cronjobs\n"), pp);
217	}
218	(void) pam_end(pamh, PAM_SUCCESS);
219
220
221	/* check for unaudited shell */
222	if (audit_crontab_not_allowed(ruid, pp))
223		crabort(AUDITREJECT);
224
225	cf = xmalloc(strlen(CRONDIR)+strlen(login)+2);
226	strcat(strcat(strcpy(cf, CRONDIR), "/"), login);
227
228	if (rflag) {
229		r = unlink(cf);
230		cron_sendmsg(DELETE, login, login, CRON);
231		audit_crontab_delete(cf, r);
232		exit(0);
233	}
234	if (lflag) {
235		if ((fp = fopen(cf, "r")) == NULL)
236			crabort(BADOPEN);
237		while (fgets(line, CTLINESIZE, fp) != NULL)
238			fputs(line, stdout);
239		fclose(fp);
240		exit(0);
241	}
242	if (eflag) {
243		if ((fp = fopen(cf, "r")) == NULL) {
244			if (errno != ENOENT)
245				crabort(BADOPEN);
246		}
247		(void) strcpy(edtemp, "/tmp/crontabXXXXXX");
248		tmpfd = mkstemp(edtemp);
249		if (fchown(tmpfd, ruid, -1) == -1) {
250			(void) close(tmpfd);
251			crabort("fchown of temporary file failed");
252		}
253		(void) close(tmpfd);
254		/*
255		 * Fork off a child with user's permissions,
256		 * to edit the crontab file
257		 */
258		if ((pid = fork()) == (pid_t)-1)
259			crabort("fork failed");
260		if (pid == 0) {		/* child process */
261			/* give up super-user privileges. */
262			setuid(ruid);
263			if ((tmpfp = fopen(edtemp, "w")) == NULL)
264				crabort("can't create temporary file");
265			if (fp != NULL) {
266				/*
267				 * Copy user's crontab file to temporary file.
268				 */
269				while (fgets(line, CTLINESIZE, fp) != NULL) {
270					fputs(line, tmpfp);
271					if (ferror(tmpfp)) {
272						fclose(fp);
273						fclose(tmpfp);
274						crabort("write error on"
275						    "temporary file");
276					}
277				}
278				if (ferror(fp)) {
279					fclose(fp);
280					fclose(tmpfp);
281					crabort(BADREAD);
282				}
283				fclose(fp);
284			}
285			if (fclose(tmpfp) == EOF)
286				crabort("write error on temporary file");
287			if (stat(edtemp, &stbuf) < 0)
288				crabort("can't stat temporary file");
289			omodtime = stbuf.st_mtime;
290#ifdef _XPG_NOTDEFINED
291			editor = getenv("VISUAL");
292			if (editor == NULL) {
293#endif
294				editor = getenv("EDITOR");
295				if (editor == NULL)
296					editor = VIPATH;
297#ifdef _XPG_NOTDEFINED
298			}
299#endif
300			(void) snprintf(buf, sizeof (buf),
301			    "%s %s", editor, edtemp);
302			sleep(1);
303
304			while (1) {
305				ret = system(buf);
306				/* sanity checks */
307				if ((tmpfp = fopen(edtemp, "r")) == NULL)
308					crabort("can't open temporary file");
309				if (fstat(fileno(tmpfp), &stbuf) < 0)
310					crabort("can't stat temporary file");
311				if (stbuf.st_size == 0)
312					crabort("temporary file empty");
313				if (omodtime == stbuf.st_mtime) {
314					(void) unlink(edtemp);
315					fprintf(stderr, gettext(
316					    "The crontab file was not"
317					    " changed.\n"));
318					exit(1);
319				}
320				if ((ret) && (errno != EINTR)) {
321				/*
322				 * Some editors (like 'vi') can return
323				 * a non-zero exit status even though
324				 * everything is okay. Need to check.
325				 */
326				fprintf(stderr, gettext(ED_ERROR));
327				fflush(stderr);
328				if (isatty(fileno(stdin))) {
329				    /* Interactive */
330					fprintf(stdout, gettext(ED_PROMPT),
331					    yesstr, nostr, nostr);
332					fflush(stdout);
333
334					if (yes()) {
335						/* Edit again */
336						continue;
337					} else {
338						/* Dump changes */
339						(void) unlink(edtemp);
340						exit(1);
341					}
342				} else {
343					/* Non-interactive, dump changes */
344					(void) unlink(edtemp);
345					exit(1);
346				}
347			}
348			exit(0);
349			} /* while (1) */
350		}
351
352		/* fix for 1125555 - ignore common signals while waiting */
353		(void) signal(SIGINT, SIG_IGN);
354		(void) signal(SIGHUP, SIG_IGN);
355		(void) signal(SIGQUIT, SIG_IGN);
356		(void) signal(SIGTERM, SIG_IGN);
357		wait(&stat_loc);
358		if ((stat_loc & 0xFF00) != 0)
359			exit(1);
360
361		if ((seteuid(ruid) < 0) ||
362		    ((tmpfp = fopen(edtemp, "r")) == NULL)) {
363			fprintf(stderr, "crontab: %s: %s\n",
364			    edtemp, errmsg(errno));
365			(void) unlink(edtemp);
366			exit(1);
367		} else
368			seteuid(0);
369
370		copycron(tmpfp);
371		(void) unlink(edtemp);
372	} else {
373		if (argc == 0)
374			copycron(stdin);
375		else if (seteuid(getuid()) != 0 || (fp = fopen(argv[0], "r"))
376		    == NULL)
377			crabort(BADOPEN);
378		else {
379			seteuid(0);
380			copycron(fp);
381		}
382	}
383	cron_sendmsg(ADD, login, login, CRON);
384/*
385 *	if (per_errno == 2)
386 *		fprintf(stderr, gettext(WARNSHELL));
387 */
388	return (0);
389}
390
391static void
392copycron(fp)
393FILE *fp;
394{
395	FILE *tfp;
396	char pid[6], *tnam_end;
397	int t;
398
399	sprintf(pid, "%-5d", getpid());
400	tnam = xmalloc(strlen(CRONDIR)+strlen(TMPFILE)+7);
401	strcat(strcat(strcat(strcpy(tnam, CRONDIR), "/"), TMPFILE), pid);
402	/* cut trailing blanks */
403	tnam_end = strchr(tnam, ' ');
404	if (tnam_end != NULL)
405		*tnam_end = 0;
406	/* catch SIGINT, SIGHUP, SIGQUIT signals */
407	if (signal(SIGINT, catch) == SIG_IGN)
408		signal(SIGINT, SIG_IGN);
409	if (signal(SIGHUP, catch) == SIG_IGN) signal(SIGHUP, SIG_IGN);
410	if (signal(SIGQUIT, catch) == SIG_IGN) signal(SIGQUIT, SIG_IGN);
411	if (signal(SIGTERM, catch) == SIG_IGN) signal(SIGTERM, SIG_IGN);
412	if ((t = creat(tnam, CRMODE)) == -1) crabort(BADCREATE);
413	if ((tfp = fdopen(t, "w")) == NULL) {
414		unlink(tnam);
415		crabort(BADCREATE);
416	}
417	err = 0;	/* if errors found, err set to 1 */
418	while (fgets(line, CTLINESIZE, fp) != NULL) {
419		cursor = 0;
420		while (line[cursor] == ' ' || line[cursor] == '\t')
421			cursor++;
422		/* fix for 1039689 - treat blank line like a comment */
423		if (line[cursor] == '#' || line[cursor] == '\n')
424			goto cont;
425		if (next_field(0, 59)) continue;
426		if (next_field(0, 23)) continue;
427		if (next_field(1, 31)) continue;
428		if (next_field(1, 12)) continue;
429		if (next_field(0, 06)) continue;
430		if (line[++cursor] == '\0') {
431			cerror(EOLN);
432			continue;
433		}
434cont:
435		if (fputs(line, tfp) == EOF) {
436			unlink(tnam);
437			crabort(BADCREATE);
438		}
439	}
440	fclose(fp);
441	fclose(tfp);
442
443	/* audit differences between old and new crontabs */
444	audit_crontab_modify(cf, tnam, err);
445
446	if (!err) {
447		/* make file tfp the new crontab */
448		unlink(cf);
449		if (link(tnam, cf) == -1) {
450			unlink(tnam);
451			crabort(BADCREATE);
452		}
453	} else
454		fprintf(stderr, "crontab: %s\n", gettext(ERRSFND));
455	unlink(tnam);
456}
457
458static int
459next_field(lower, upper)
460int lower, upper;
461{
462	int num, num2;
463
464	while ((line[cursor] == ' ') || (line[cursor] == '\t')) cursor++;
465	if (line[cursor] == '\0') {
466		cerror(EOLN);
467		return (1);
468	}
469	if (line[cursor] == '*') {
470		cursor++;
471		if ((line[cursor] != ' ') && (line[cursor] != '\t')) {
472			cerror(UNEXPECT);
473			return (1);
474		}
475		return (0);
476	}
477	while (TRUE) {
478		if (!isdigit(line[cursor])) {
479			cerror(UNEXPECT);
480			return (1);
481		}
482		num = 0;
483		do {
484			num = num*10 + (line[cursor]-'0');
485		} while (isdigit(line[++cursor]));
486		if ((num < lower) || (num > upper)) {
487			cerror(OUTOFBOUND);
488			return (1);
489		}
490		if (line[cursor] == '-') {
491			if (!isdigit(line[++cursor])) {
492				cerror(UNEXPECT);
493				return (1);
494			}
495			num2 = 0;
496			do {
497				num2 = num2*10 + (line[cursor]-'0');
498			} while (isdigit(line[++cursor]));
499			if ((num2 < lower) || (num2 > upper)) {
500				cerror(OUTOFBOUND);
501				return (1);
502			}
503		}
504		if ((line[cursor] == ' ') || (line[cursor] == '\t')) break;
505		if (line[cursor] == '\0') {
506			cerror(EOLN);
507			return (1);
508		}
509		if (line[cursor++] != ',') {
510			cerror(UNEXPECT);
511			return (1);
512		}
513	}
514	return (0);
515}
516
517static void
518cerror(msg)
519char *msg;
520{
521	fprintf(stderr, gettext("%scrontab: error on previous line; %s\n"),
522	    line, msg);
523	err = 1;
524}
525
526
527static void
528catch(int x)
529{
530	unlink(tnam);
531	exit(1);
532}
533
534static void
535crabort(msg)
536char *msg;
537{
538	int sverrno;
539
540	if (strcmp(edtemp, "") != 0) {
541		sverrno = errno;
542		(void) unlink(edtemp);
543		errno = sverrno;
544	}
545	if (tnam != NULL) {
546		sverrno = errno;
547		(void) unlink(tnam);
548		errno = sverrno;
549	}
550	fprintf(stderr, "crontab: %s\n", gettext(msg));
551	exit(1);
552}
553