crontab.c revision 1818:e8dfcbd4692e 
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 2006 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
51#if defined(XPG4)
52#define	VIPATH	"/usr/xpg4/bin/vi"
53#elif defined(XPG6)
54#define	VIPATH	"/usr/xpg6/bin/vi"
55#else
56#define	_XPG_NOTDEFINED
57#define	VIPATH	"vi"
58#endif
59
60#define	TMPFILE		"_cron"		/* prefix for tmp file */
61#define	CRMODE		0600	/* mode for creating crontabs */
62
63#define	BADCREATE	\
64	"can't create your crontab file in the crontab directory."
65#define	BADOPEN		"can't open your crontab file."
66#define	BADSHELL	\
67	"because your login shell isn't /usr/bin/sh, you can't use cron."
68#define	WARNSHELL	"warning: commands will be executed using /usr/bin/sh\n"
69#define	BADUSAGE	\
70	"usage:\n"			\
71	"\tcrontab [file]\n"		\
72	"\tcrontab -e [username]\n"	\
73	"\tcrontab -l [username]\n"	\
74	"\tcrontab -r [username]"
75#define	INVALIDUSER	"you are not a valid user (no entry in /etc/passwd)."
76#define	NOTALLOWED	"you are not authorized to use cron.  Sorry."
77#define	NOTROOT		\
78	"you must be super-user to access another user's crontab file"
79#define	AUDITREJECT	"The audit context for your shell has not been set."
80#define	EOLN		"unexpected end of line."
81#define	UNEXPECT	"unexpected character found in line."
82#define	OUTOFBOUND	"number out of bounds."
83#define	ERRSFND		"errors detected in input, no crontab file generated."
84#define	ED_ERROR	\
85	"     The editor indicates that an error occurred while you were\n"\
86	"     editing the crontab data - usually a minor typing error.\n\n"
87#define	BADREAD		"error reading your crontab file"
88#define	ED_PROMPT	\
89	"     Edit again, to ensure crontab information is intact (%c/%c)?\n"\
90	"     ('%c' will discard edits.)"
91#define	NAMETOOLONG	"login name too long"
92
93extern int	per_errno;
94
95extern int	audit_crontab_modify(char *, char *, int);
96extern int	audit_crontab_delete(char *, int);
97extern int	audit_crontab_not_allowed(uid_t, char *);
98
99int		err;
100int		cursor;
101char		*cf;
102char		*tnam;
103char		edtemp[5+13+1];
104char		line[CTLINESIZE];
105static		char	login[UNAMESIZE];
106static		char	yeschr;
107static		char	nochr;
108
109static int yes(void);
110static int next_field(int, int);
111static void catch(int);
112static void crabort(char *);
113static void cerror(char *);
114static void copycron(FILE *);
115
116int
117main(int argc, char **argv)
118{
119	int	c, r;
120	int	rflag	= 0;
121	int	lflag	= 0;
122	int	eflag	= 0;
123	int	errflg	= 0;
124	char *pp;
125	FILE *fp, *tmpfp;
126	struct stat stbuf;
127	struct passwd *pwp;
128	time_t omodtime;
129	char *editor;
130	char buf[BUFSIZ];
131	uid_t ruid;
132	pid_t pid;
133	int stat_loc;
134	int ret;
135	char real_login[UNAMESIZE];
136	int tmpfd = -1;
137	pam_handle_t *pamh;
138	int pam_error;
139
140	(void) setlocale(LC_ALL, "");
141#if !defined(TEXT_DOMAIN)	/* Should be defined by cc -D */
142#define	TEXT_DOMAIN "SYS_TEST"	/* Use this only if it weren't */
143#endif
144	(void) textdomain(TEXT_DOMAIN);
145	yeschr = *nl_langinfo(YESSTR);
146	nochr = *nl_langinfo(NOSTR);
147
148	while ((c = getopt(argc, argv, "elr")) != EOF)
149		switch (c) {
150			case 'e':
151				eflag++;
152				break;
153			case 'l':
154				lflag++;
155				break;
156			case 'r':
157				rflag++;
158				break;
159			case '?':
160				errflg++;
161				break;
162		}
163
164	if (eflag + lflag + rflag > 1)
165		errflg++;
166
167	argc -= optind;
168	argv += optind;
169	if (errflg || argc > 1)
170		crabort(BADUSAGE);
171
172	ruid = getuid();
173	if ((pwp = getpwuid(ruid)) == NULL)
174		crabort(INVALIDUSER);
175
176	if (strlcpy(real_login, pwp->pw_name, sizeof (real_login))
177	    >= sizeof (real_login))
178		crabort(NAMETOOLONG);
179
180	if ((eflag || lflag || rflag) && argc == 1) {
181		if ((pwp = getpwnam(*argv)) == NULL)
182			crabort(INVALIDUSER);
183
184		if (!chkauthattr(CRONADMIN_AUTH, real_login)) {
185			if (pwp->pw_uid != ruid)
186				crabort(NOTROOT);
187			else
188				pp = getuser(ruid);
189		} else
190			pp = *argv++;
191	} else {
192		pp = getuser(ruid);
193	}
194
195	if (pp == NULL) {
196		if (per_errno == 2)
197			crabort(BADSHELL);
198		else
199			crabort(INVALIDUSER);
200	}
201	if (strlcpy(login, pp, sizeof (login)) >= sizeof (login))
202		crabort(NAMETOOLONG);
203	if (!allowed(login, CRONALLOW, CRONDENY))
204		crabort(NOTALLOWED);
205
206	/* Do account validation check */
207	pam_error = pam_start("cron", pp, NULL, &pamh);
208	if (pam_error != PAM_SUCCESS) {
209		crabort((char *)pam_strerror(pamh, pam_error));
210	}
211	pam_error = pam_acct_mgmt(pamh, PAM_SILENT);
212	if (pam_error != PAM_SUCCESS) {
213		(void) fprintf(stderr, gettext("Warning - Invalid account: "
214		    "'%s' not allowed to execute cronjobs\n"), pp);
215	}
216	(void) pam_end(pamh, PAM_SUCCESS);
217
218
219	/* check for unaudited shell */
220	if (audit_crontab_not_allowed(ruid, pp))
221		crabort(AUDITREJECT);
222
223	cf = xmalloc(strlen(CRONDIR)+strlen(login)+2);
224	strcat(strcat(strcpy(cf, CRONDIR), "/"), login);
225
226	if (rflag) {
227		r = unlink(cf);
228		cron_sendmsg(DELETE, login, login, CRON);
229		audit_crontab_delete(cf, r);
230		exit(0);
231	}
232	if (lflag) {
233		if ((fp = fopen(cf, "r")) == NULL)
234			crabort(BADOPEN);
235		while (fgets(line, CTLINESIZE, fp) != NULL)
236			fputs(line, stdout);
237		fclose(fp);
238		exit(0);
239	}
240	if (eflag) {
241		if ((fp = fopen(cf, "r")) == NULL) {
242			if (errno != ENOENT)
243				crabort(BADOPEN);
244		}
245		(void) strcpy(edtemp, "/tmp/crontabXXXXXX");
246		tmpfd = mkstemp(edtemp);
247		if (fchown(tmpfd, ruid, -1) == -1) {
248			(void) close(tmpfd);
249			crabort("fchown of temporary file failed");
250		}
251		(void) close(tmpfd);
252		/*
253		 * Fork off a child with user's permissions,
254		 * to edit the crontab file
255		 */
256		if ((pid = fork()) == (pid_t)-1)
257			crabort("fork failed");
258		if (pid == 0) {		/* child process */
259			/* give up super-user privileges. */
260			setuid(ruid);
261			if ((tmpfp = fopen(edtemp, "w")) == NULL)
262				crabort("can't create temporary file");
263			if (fp != NULL) {
264				/*
265				 * Copy user's crontab file to temporary file.
266				 */
267				while (fgets(line, CTLINESIZE, fp) != NULL) {
268					fputs(line, tmpfp);
269					if (ferror(tmpfp)) {
270						fclose(fp);
271						fclose(tmpfp);
272						crabort("write error on"
273						    "temporary file");
274					}
275				}
276				if (ferror(fp)) {
277					fclose(fp);
278					fclose(tmpfp);
279					crabort(BADREAD);
280				}
281				fclose(fp);
282			}
283			if (fclose(tmpfp) == EOF)
284				crabort("write error on temporary file");
285			if (stat(edtemp, &stbuf) < 0)
286				crabort("can't stat temporary file");
287			omodtime = stbuf.st_mtime;
288#ifdef _XPG_NOTDEFINED
289			editor = getenv("VISUAL");
290			if (editor == NULL) {
291#endif
292				editor = getenv("EDITOR");
293				if (editor == NULL)
294					editor = VIPATH;
295#ifdef _XPG_NOTDEFINED
296			}
297#endif
298			(void) snprintf(buf, sizeof (buf),
299				"%s %s", editor, edtemp);
300			sleep(1);
301
302			while (1) {
303				ret = system(buf);
304				/* sanity checks */
305				if ((tmpfp = fopen(edtemp, "r")) == NULL)
306				    crabort("can't open temporary file");
307				if (fstat(fileno(tmpfp), &stbuf) < 0)
308				    crabort("can't stat temporary file");
309				if (stbuf.st_size == 0)
310				    crabort("temporary file empty");
311				if (omodtime == stbuf.st_mtime) {
312				    (void) unlink(edtemp);
313				    fprintf(stderr, gettext(
314					"The crontab file was not changed.\n"));
315				    exit(1);
316				}
317				if ((ret) && (errno != EINTR)) {
318				/*
319				 * Some editors (like 'vi') can return
320				 * a non-zero exit status even though
321				 * everything is okay. Need to check.
322				 */
323				fprintf(stderr, gettext(ED_ERROR));
324				fflush(stderr);
325				if (isatty(fileno(stdin))) {
326				    /* Interactive */
327					fprintf(stdout, gettext(ED_PROMPT),
328					    yeschr, nochr, nochr);
329					fflush(stdout);
330
331					if (yes()) {
332						/* Edit again */
333						continue;
334					} else {
335						/* Dump changes */
336						(void) unlink(edtemp);
337						exit(1);
338					}
339				} else {
340				    /* Non-interactive, dump changes */
341				    (void) unlink(edtemp);
342				    exit(1);
343				}
344			}
345			exit(0);
346			} /* while (1) */
347		}
348
349		/* fix for 1125555 - ignore common signals while waiting */
350		(void) signal(SIGINT, SIG_IGN);
351		(void) signal(SIGHUP, SIG_IGN);
352		(void) signal(SIGQUIT, SIG_IGN);
353		(void) signal(SIGTERM, SIG_IGN);
354		wait(&stat_loc);
355		if ((stat_loc & 0xFF00) != 0)
356			exit(1);
357
358		if ((seteuid(ruid) < 0) ||
359		    ((tmpfp = fopen(edtemp, "r")) == NULL)) {
360			fprintf(stderr, "crontab: %s: %s\n",
361			    edtemp, errmsg(errno));
362			(void) unlink(edtemp);
363			exit(1);
364		} else
365			seteuid(0);
366
367		copycron(tmpfp);
368		(void) unlink(edtemp);
369	} else {
370		if (argc == 0)
371			copycron(stdin);
372		else if (seteuid(getuid()) != 0 || (fp = fopen(argv[0], "r"))
373		    == NULL)
374			crabort(BADOPEN);
375		else {
376			seteuid(0);
377			copycron(fp);
378		}
379	}
380	cron_sendmsg(ADD, login, login, CRON);
381/*
382 *	if (per_errno == 2)
383 *		fprintf(stderr, gettext(WARNSHELL));
384 */
385	return (0);
386}
387
388static void
389copycron(fp)
390FILE *fp;
391{
392	FILE *tfp;
393	char pid[6], *tnam_end;
394	int t;
395
396	sprintf(pid, "%-5d", getpid());
397	tnam = xmalloc(strlen(CRONDIR)+strlen(TMPFILE)+7);
398	strcat(strcat(strcat(strcpy(tnam, CRONDIR), "/"), TMPFILE), pid);
399	/* cut trailing blanks */
400	tnam_end = strchr(tnam, ' ');
401	if (tnam_end != NULL)
402		*tnam_end = 0;
403	/* catch SIGINT, SIGHUP, SIGQUIT signals */
404	if (signal(SIGINT, catch) == SIG_IGN)
405		signal(SIGINT, SIG_IGN);
406	if (signal(SIGHUP, catch) == SIG_IGN) signal(SIGHUP, SIG_IGN);
407	if (signal(SIGQUIT, catch) == SIG_IGN) signal(SIGQUIT, SIG_IGN);
408	if (signal(SIGTERM, catch) == SIG_IGN) signal(SIGTERM, SIG_IGN);
409	if ((t = creat(tnam, CRMODE)) == -1) crabort(BADCREATE);
410	if ((tfp = fdopen(t, "w")) == NULL) {
411		unlink(tnam);
412		crabort(BADCREATE);
413	}
414	err = 0;	/* if errors found, err set to 1 */
415	while (fgets(line, CTLINESIZE, fp) != NULL) {
416		cursor = 0;
417		while (line[cursor] == ' ' || line[cursor] == '\t')
418			cursor++;
419		/* fix for 1039689 - treat blank line like a comment */
420		if (line[cursor] == '#' || line[cursor] == '\n')
421			goto cont;
422		if (next_field(0, 59)) continue;
423		if (next_field(0, 23)) continue;
424		if (next_field(1, 31)) continue;
425		if (next_field(1, 12)) continue;
426		if (next_field(0, 06)) continue;
427		if (line[++cursor] == '\0') {
428			cerror(EOLN);
429			continue;
430		}
431cont:
432		if (fputs(line, tfp) == EOF) {
433			unlink(tnam);
434			crabort(BADCREATE);
435		}
436	}
437	fclose(fp);
438	fclose(tfp);
439
440	/* audit differences between old and new crontabs */
441	audit_crontab_modify(cf, tnam, err);
442
443	if (!err) {
444		/* make file tfp the new crontab */
445		unlink(cf);
446		if (link(tnam, cf) == -1) {
447			unlink(tnam);
448			crabort(BADCREATE);
449		}
450	} else
451		fprintf(stderr, "crontab: %s\n", gettext(ERRSFND));
452	unlink(tnam);
453}
454
455static int
456next_field(lower, upper)
457int lower, upper;
458{
459	int num, num2;
460
461	while ((line[cursor] == ' ') || (line[cursor] == '\t')) cursor++;
462	if (line[cursor] == '\0') {
463		cerror(EOLN);
464		return (1);
465	}
466	if (line[cursor] == '*') {
467		cursor++;
468		if ((line[cursor] != ' ') && (line[cursor] != '\t')) {
469			cerror(UNEXPECT);
470			return (1);
471		}
472		return (0);
473	}
474	while (TRUE) {
475		if (!isdigit(line[cursor])) {
476			cerror(UNEXPECT);
477			return (1);
478		}
479		num = 0;
480		do {
481			num = num*10 + (line[cursor]-'0');
482		} while (isdigit(line[++cursor]));
483		if ((num < lower) || (num > upper)) {
484			cerror(OUTOFBOUND);
485			return (1);
486		}
487		if (line[cursor] == '-') {
488			if (!isdigit(line[++cursor])) {
489				cerror(UNEXPECT);
490				return (1);
491			}
492			num2 = 0;
493			do {
494				num2 = num2*10 + (line[cursor]-'0');
495			} while (isdigit(line[++cursor]));
496			if ((num2 < lower) || (num2 > upper)) {
497				cerror(OUTOFBOUND);
498				return (1);
499			}
500		}
501		if ((line[cursor] == ' ') || (line[cursor] == '\t')) break;
502		if (line[cursor] == '\0') {
503			cerror(EOLN);
504			return (1);
505		}
506		if (line[cursor++] != ',') {
507			cerror(UNEXPECT);
508			return (1);
509		}
510	}
511	return (0);
512}
513
514static void
515cerror(msg)
516char *msg;
517{
518	fprintf(stderr, gettext("%scrontab: error on previous line; %s\n"),
519	    line, msg);
520	err = 1;
521}
522
523
524static void
525catch(int x)
526{
527	unlink(tnam);
528	exit(1);
529}
530
531static void
532crabort(msg)
533char *msg;
534{
535	int sverrno;
536
537	if (strcmp(edtemp, "") != 0) {
538		sverrno = errno;
539		(void) unlink(edtemp);
540		errno = sverrno;
541	}
542	if (tnam != NULL) {
543		sverrno = errno;
544		(void) unlink(tnam);
545		errno = sverrno;
546	}
547	fprintf(stderr, "crontab: %s\n", gettext(msg));
548	exit(1);
549}
550
551static int
552yes(void)
553{
554	int	first_char;
555	int	dummy_char;
556
557	first_char = dummy_char = getchar();
558	while ((dummy_char != '\n')	&&
559	    (dummy_char != '\0')	&&
560	    (dummy_char != EOF))
561		dummy_char = getchar();
562	return (first_char == yeschr);
563}
564