crontab.c revision 8439:51a23ac0d2a6 
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 2008 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#include <sys/types.h>
30#include <sys/stat.h>
31#include <sys/types.h>
32#include <sys/wait.h>
33#include <errno.h>
34#include <signal.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38#include <fcntl.h>
39#include <ctype.h>
40#include <pwd.h>
41#include <unistd.h>
42#include <locale.h>
43#include <nl_types.h>
44#include <langinfo.h>
45#include <libintl.h>
46#include <spawn.h>
47#include <security/pam_appl.h>
48#include <limits.h>
49#include <libzoneinfo.h>
50#include "cron.h"
51#include "getresponse.h"
52
53#if defined(XPG4)
54#define	VIPATH	"/usr/xpg4/bin/vi"
55#elif defined(XPG6)
56#define	VIPATH	"/usr/xpg6/bin/vi"
57#else
58#define	_XPG_NOTDEFINED
59#define	VIPATH	"vi"
60#endif
61
62#define	TMPFILE		"_cron"		/* prefix for tmp file */
63#define	CRMODE		0600	/* mode for creating crontabs */
64
65#define	BADCREATE	\
66	"can't create your crontab file in the crontab directory."
67#define	BADOPEN		"can't open your crontab file."
68#define	BADSHELL	\
69	"because your login shell isn't /usr/bin/sh, you can't use cron."
70#define	WARNSHELL	"warning: commands will be executed using /usr/bin/sh\n"
71#define	BADUSAGE	\
72	"usage:\n"			\
73	"\tcrontab [file]\n"		\
74	"\tcrontab -e [username]\n"	\
75	"\tcrontab -l [username]\n"	\
76	"\tcrontab -r [username]"
77#define	INVALIDUSER	"you are not a valid user (no entry in /etc/passwd)."
78#define	NOTALLOWED	"you are not authorized to use cron.  Sorry."
79#define	NOTROOT		\
80	"you must be super-user to access another user's crontab file"
81#define	AUDITREJECT	"The audit context for your shell has not been set."
82#define	EOLN		"unexpected end of line."
83#define	UNEXPECT	"unexpected character found in line."
84#define	OUTOFBOUND	"number out of bounds."
85#define	ERRSFND		"errors detected in input, no crontab file generated."
86#define	ED_ERROR	\
87	"     The editor indicates that an error occurred while you were\n"\
88	"     editing the crontab data - usually a minor typing error.\n\n"
89#define	BADREAD		"error reading your crontab file"
90#define	ED_PROMPT	\
91	"     Edit again, to ensure crontab information is intact (%s/%s)?\n"\
92	"     ('%s' will discard edits.)"
93#define	NAMETOOLONG	"login name too long"
94#define	BAD_TZ	"Timezone unrecognized in: %s"
95#define	BAD_SHELL	"Invalid shell specified: %s"
96#define	BAD_HOME	"Unable to access directory: %s\t%s\n"
97
98extern int	per_errno;
99extern char 	**environ;
100
101extern int	audit_crontab_modify(char *, char *, int);
102extern int	audit_crontab_delete(char *, int);
103extern int	audit_crontab_not_allowed(uid_t, char *);
104
105int		err;
106int		cursor;
107char		*cf;
108char		*tnam;
109char		edtemp[5+13+1];
110char		line[CTLINESIZE];
111static		char	login[UNAMESIZE];
112
113static int	next_field(int, int);
114static void	catch(int);
115static void	crabort(char *);
116static void	cerror(char *);
117static void	copycron(FILE *);
118
119int
120main(int argc, char **argv)
121{
122	int	c, r;
123	int	rflag	= 0;
124	int	lflag	= 0;
125	int	eflag	= 0;
126	int	errflg	= 0;
127	char *pp;
128	FILE *fp, *tmpfp;
129	struct stat stbuf;
130	struct passwd *pwp;
131	time_t omodtime;
132	char *editor;
133	uid_t ruid;
134	pid_t pid;
135	int stat_loc;
136	int ret;
137	char real_login[UNAMESIZE];
138	int tmpfd = -1;
139	pam_handle_t *pamh;
140	int pam_error;
141	pid_t cpid;
142	int cstatus;
143	char *argvec[3];
144
145	(void) setlocale(LC_ALL, "");
146#if !defined(TEXT_DOMAIN)	/* Should be defined by cc -D */
147#define	TEXT_DOMAIN "SYS_TEST"	/* Use this only if it weren't */
148#endif
149	(void) textdomain(TEXT_DOMAIN);
150
151	if (init_yes() < 0) {
152		(void) fprintf(stderr, gettext(ERR_MSG_INIT_YES),
153		    strerror(errno));
154		exit(1);
155	}
156
157	while ((c = getopt(argc, argv, "elr")) != EOF)
158		switch (c) {
159			case 'e':
160				eflag++;
161				break;
162			case 'l':
163				lflag++;
164				break;
165			case 'r':
166				rflag++;
167				break;
168			case '?':
169				errflg++;
170				break;
171		}
172
173	if (eflag + lflag + rflag > 1)
174		errflg++;
175
176	argc -= optind;
177	argv += optind;
178	if (errflg || argc > 1)
179		crabort(BADUSAGE);
180
181	ruid = getuid();
182	if ((pwp = getpwuid(ruid)) == NULL)
183		crabort(INVALIDUSER);
184
185	if (strlcpy(real_login, pwp->pw_name, sizeof (real_login))
186	    >= sizeof (real_login))
187		crabort(NAMETOOLONG);
188
189	if ((eflag || lflag || rflag) && argc == 1) {
190		if ((pwp = getpwnam(*argv)) == NULL)
191			crabort(INVALIDUSER);
192
193		if (!chkauthattr(CRONADMIN_AUTH, real_login)) {
194			if (pwp->pw_uid != ruid)
195				crabort(NOTROOT);
196			else
197				pp = getuser(ruid);
198		} else
199			pp = *argv++;
200	} else {
201		pp = getuser(ruid);
202	}
203
204	if (pp == NULL) {
205		if (per_errno == 2)
206			crabort(BADSHELL);
207		else
208			crabort(INVALIDUSER);
209	}
210	if (strlcpy(login, pp, sizeof (login)) >= sizeof (login))
211		crabort(NAMETOOLONG);
212	if (!allowed(login, CRONALLOW, CRONDENY))
213		crabort(NOTALLOWED);
214
215	/* Do account validation check */
216	pam_error = pam_start("cron", pp, NULL, &pamh);
217	if (pam_error != PAM_SUCCESS) {
218		crabort((char *)pam_strerror(pamh, pam_error));
219	}
220	pam_error = pam_acct_mgmt(pamh, PAM_SILENT);
221	if (pam_error != PAM_SUCCESS) {
222		(void) fprintf(stderr, gettext("Warning - Invalid account: "
223		    "'%s' not allowed to execute cronjobs\n"), pp);
224	}
225	(void) pam_end(pamh, PAM_SUCCESS);
226
227
228	/* check for unaudited shell */
229	if (audit_crontab_not_allowed(ruid, pp))
230		crabort(AUDITREJECT);
231
232	cf = xmalloc(strlen(CRONDIR)+strlen(login)+2);
233	strcat(strcat(strcpy(cf, CRONDIR), "/"), login);
234
235	if (rflag) {
236		r = unlink(cf);
237		cron_sendmsg(DELETE, login, login, CRON);
238		audit_crontab_delete(cf, r);
239		exit(0);
240	}
241	if (lflag) {
242		if ((fp = fopen(cf, "r")) == NULL)
243			crabort(BADOPEN);
244		while (fgets(line, CTLINESIZE, fp) != NULL)
245			fputs(line, stdout);
246		fclose(fp);
247		exit(0);
248	}
249	if (eflag) {
250		if ((fp = fopen(cf, "r")) == NULL) {
251			if (errno != ENOENT)
252				crabort(BADOPEN);
253		}
254		(void) strcpy(edtemp, "/tmp/crontabXXXXXX");
255		tmpfd = mkstemp(edtemp);
256		if (fchown(tmpfd, ruid, -1) == -1) {
257			(void) close(tmpfd);
258			crabort("fchown of temporary file failed");
259		}
260		(void) close(tmpfd);
261		/*
262		 * Fork off a child with user's permissions,
263		 * to edit the crontab file
264		 */
265		if ((pid = fork()) == (pid_t)-1)
266			crabort("fork failed");
267		if (pid == 0) {		/* child process */
268			/* give up super-user privileges. */
269			setuid(ruid);
270			if ((tmpfp = fopen(edtemp, "w")) == NULL)
271				crabort("can't create temporary file");
272			if (fp != NULL) {
273				/*
274				 * Copy user's crontab file to temporary file.
275				 */
276				while (fgets(line, CTLINESIZE, fp) != NULL) {
277					fputs(line, tmpfp);
278					if (ferror(tmpfp)) {
279						fclose(fp);
280						fclose(tmpfp);
281						crabort("write error on"
282						    "temporary file");
283					}
284				}
285				if (ferror(fp)) {
286					fclose(fp);
287					fclose(tmpfp);
288					crabort(BADREAD);
289				}
290				fclose(fp);
291			}
292			if (fclose(tmpfp) == EOF)
293				crabort("write error on temporary file");
294			if (stat(edtemp, &stbuf) < 0)
295				crabort("can't stat temporary file");
296			omodtime = stbuf.st_mtime;
297#ifdef _XPG_NOTDEFINED
298			editor = getenv("VISUAL");
299			if (editor == NULL) {
300#endif
301				editor = getenv("EDITOR");
302				if (editor == NULL)
303					editor = VIPATH;
304#ifdef _XPG_NOTDEFINED
305			}
306#endif
307			argvec[0] = strdup(editor);
308			argvec[1] = strdup(edtemp);
309			argvec[2] = NULL;
310
311			if (argvec[0] == NULL || argvec[1] == NULL)
312				crabort("Insufficient memory");
313
314			sleep(1);
315
316			while (1) {
317				/*
318				 * posix_spawnp() allows the file pointed to
319				 * by the 'EDITOR' variable to be searched in
320				 * the PATH environment variable
321				 */
322
323				ret = posix_spawnp(&cpid, editor, NULL, NULL,
324				    (char *const *)argvec,
325				    (char *const *)environ);
326				if (ret) {
327					(void) fprintf(stderr,
328					    gettext("crontab: %s: %s\n"),
329					    editor, strerror(errno));
330					cstatus = -1;
331				} else {
332					pid_t wpid = 0;
333					while ((wpid = waitpid(cpid, &cstatus,
334					    0)) == -1 && errno == EINTR)
335						;
336					if (wpid  == -1)
337						cstatus = -1;
338				}
339
340				/* sanity checks */
341				if ((tmpfp = fopen(edtemp, "r")) == NULL)
342					crabort("can't open temporary file");
343				if (fstat(fileno(tmpfp), &stbuf) < 0)
344					crabort("can't stat temporary file");
345				if (stbuf.st_size == 0)
346					crabort("temporary file empty");
347				if (omodtime == stbuf.st_mtime) {
348					(void) unlink(edtemp);
349					fprintf(stderr, gettext(
350					    "The crontab file was not"
351					    " changed.\n"));
352					exit(1);
353				}
354				if ((cstatus) && (errno != EINTR)) {
355					/*
356					 * Some editors (like 'vi') can return
357					 * a non-zero exit status even though
358					 * everything is okay. Need to check.
359					 */
360					fprintf(stderr, gettext(ED_ERROR));
361					fflush(stderr);
362					if (isatty(fileno(stdin))) {
363						/* Interactive */
364						fprintf(stdout,
365						    gettext(ED_PROMPT),
366						    yesstr, nostr, nostr);
367						fflush(stdout);
368
369						if (yes()) {
370							/* Edit again */
371							continue;
372						} else {
373							/* Dump changes */
374							(void) unlink(edtemp);
375							exit(1);
376						}
377					} else {
378						/*
379						 * Non-interactive, dump changes
380						 */
381						(void) unlink(edtemp);
382						exit(1);
383					}
384				}
385				exit(0);
386			} /* while (1) */
387		}
388
389		/* fix for 1125555 - ignore common signals while waiting */
390		(void) signal(SIGINT, SIG_IGN);
391		(void) signal(SIGHUP, SIG_IGN);
392		(void) signal(SIGQUIT, SIG_IGN);
393		(void) signal(SIGTERM, SIG_IGN);
394		wait(&stat_loc);
395		if ((stat_loc & 0xFF00) != 0)
396			exit(1);
397
398		/*
399		 * unlink edtemp as 'ruid'. The file contents will be held
400		 * since we open the file descriptor 'tmpfp' before calling
401		 * unlink.
402		 */
403		if (((ret = seteuid(ruid)) < 0) ||
404		    ((tmpfp = fopen(edtemp, "r")) == NULL) ||
405		    (unlink(edtemp) == -1)) {
406			fprintf(stderr, "crontab: %s: %s\n",
407			    edtemp, errmsg(errno));
408			if ((ret < 0) || (tmpfp == NULL))
409				(void) unlink(edtemp);
410			exit(1);
411		} else
412			seteuid(0);
413
414		copycron(tmpfp);
415	} else {
416		if (argc == 0)
417			copycron(stdin);
418		else if (seteuid(getuid()) != 0 || (fp = fopen(argv[0], "r"))
419		    == NULL)
420			crabort(BADOPEN);
421		else {
422			seteuid(0);
423			copycron(fp);
424		}
425	}
426	cron_sendmsg(ADD, login, login, CRON);
427/*
428 *	if (per_errno == 2)
429 *		fprintf(stderr, gettext(WARNSHELL));
430 */
431	return (0);
432}
433
434static void
435copycron(fp)
436FILE *fp;
437{
438	FILE *tfp;
439	char pid[6], *tnam_end;
440	int t;
441	char buf[LINE_MAX];
442
443	sprintf(pid, "%-5d", getpid());
444	tnam = xmalloc(strlen(CRONDIR)+strlen(TMPFILE)+7);
445	strcat(strcat(strcat(strcpy(tnam, CRONDIR), "/"), TMPFILE), pid);
446	/* cut trailing blanks */
447	tnam_end = strchr(tnam, ' ');
448	if (tnam_end != NULL)
449		*tnam_end = 0;
450	/* catch SIGINT, SIGHUP, SIGQUIT signals */
451	if (signal(SIGINT, catch) == SIG_IGN)
452		signal(SIGINT, SIG_IGN);
453	if (signal(SIGHUP, catch) == SIG_IGN) signal(SIGHUP, SIG_IGN);
454	if (signal(SIGQUIT, catch) == SIG_IGN) signal(SIGQUIT, SIG_IGN);
455	if (signal(SIGTERM, catch) == SIG_IGN) signal(SIGTERM, SIG_IGN);
456	if ((t = creat(tnam, CRMODE)) == -1) crabort(BADCREATE);
457	if ((tfp = fdopen(t, "w")) == NULL) {
458		unlink(tnam);
459		crabort(BADCREATE);
460	}
461	err = 0;	/* if errors found, err set to 1 */
462	while (fgets(line, CTLINESIZE, fp) != NULL) {
463		cursor = 0;
464		while (line[cursor] == ' ' || line[cursor] == '\t')
465			cursor++;
466		/* fix for 1039689 - treat blank line like a comment */
467		if (line[cursor] == '#' || line[cursor] == '\n')
468			goto cont;
469
470		if (strncmp(&line[cursor], ENV_TZ, strlen(ENV_TZ)) == 0) {
471			char *x;
472
473			strncpy(buf, &line[cursor + strlen(ENV_TZ)],
474			    sizeof (buf));
475			if ((x = strchr(buf, '\n')) != NULL)
476				*x = NULL;
477
478			if (isvalid_tz(buf, NULL, _VTZ_ALL)) {
479				goto cont;
480			} else {
481				err = 1;
482				fprintf(stderr, BAD_TZ, &line[cursor]);
483				continue;
484			}
485		} else if (strncmp(&line[cursor], ENV_SHELL,
486		    strlen(ENV_SHELL)) == 0) {
487			char *x;
488
489			strncpy(buf, &line[cursor + strlen(ENV_SHELL)],
490			    sizeof (buf));
491			if ((x = strchr(buf, '\n')) != NULL)
492				*x = NULL;
493
494			if (isvalid_shell(buf)) {
495				goto cont;
496			} else {
497				err = 1;
498				fprintf(stderr, BAD_SHELL, &line[cursor]);
499				continue;
500			}
501		} else if (strncmp(&line[cursor], ENV_HOME,
502		    strlen(ENV_HOME)) == 0) {
503			char *x;
504
505			strncpy(buf, &line[cursor + strlen(ENV_HOME)],
506			    sizeof (buf));
507			if ((x = strchr(buf, '\n')) != NULL)
508				*x = NULL;
509			if (chdir(buf) == 0) {
510				goto cont;
511			} else {
512				err = 1;
513				fprintf(stderr, BAD_HOME, &line[cursor],
514				    strerror(errno));
515				continue;
516			}
517		}
518
519		if (next_field(0, 59)) continue;
520		if (next_field(0, 23)) continue;
521		if (next_field(1, 31)) continue;
522		if (next_field(1, 12)) continue;
523		if (next_field(0, 06)) continue;
524		if (line[++cursor] == '\0') {
525			cerror(EOLN);
526			continue;
527		}
528cont:
529		if (fputs(line, tfp) == EOF) {
530			unlink(tnam);
531			crabort(BADCREATE);
532		}
533	}
534	fclose(fp);
535	fclose(tfp);
536
537	/* audit differences between old and new crontabs */
538	audit_crontab_modify(cf, tnam, err);
539
540	if (!err) {
541		/* make file tfp the new crontab */
542		unlink(cf);
543		if (link(tnam, cf) == -1) {
544			unlink(tnam);
545			crabort(BADCREATE);
546		}
547	} else
548		fprintf(stderr, "crontab: %s\n", gettext(ERRSFND));
549	unlink(tnam);
550}
551
552static int
553next_field(lower, upper)
554int lower, upper;
555{
556	int num, num2;
557
558	while ((line[cursor] == ' ') || (line[cursor] == '\t')) cursor++;
559	if (line[cursor] == '\0') {
560		cerror(EOLN);
561		return (1);
562	}
563	if (line[cursor] == '*') {
564		cursor++;
565		if ((line[cursor] != ' ') && (line[cursor] != '\t')) {
566			cerror(UNEXPECT);
567			return (1);
568		}
569		return (0);
570	}
571	while (TRUE) {
572		if (!isdigit(line[cursor])) {
573			cerror(UNEXPECT);
574			return (1);
575		}
576		num = 0;
577		do {
578			num = num*10 + (line[cursor]-'0');
579		} while (isdigit(line[++cursor]));
580		if ((num < lower) || (num > upper)) {
581			cerror(OUTOFBOUND);
582			return (1);
583		}
584		if (line[cursor] == '-') {
585			if (!isdigit(line[++cursor])) {
586				cerror(UNEXPECT);
587				return (1);
588			}
589			num2 = 0;
590			do {
591				num2 = num2*10 + (line[cursor]-'0');
592			} while (isdigit(line[++cursor]));
593			if ((num2 < lower) || (num2 > upper)) {
594				cerror(OUTOFBOUND);
595				return (1);
596			}
597		}
598		if ((line[cursor] == ' ') || (line[cursor] == '\t')) break;
599		if (line[cursor] == '\0') {
600			cerror(EOLN);
601			return (1);
602		}
603		if (line[cursor++] != ',') {
604			cerror(UNEXPECT);
605			return (1);
606		}
607	}
608	return (0);
609}
610
611static void
612cerror(msg)
613char *msg;
614{
615	fprintf(stderr, gettext("%scrontab: error on previous line; %s\n"),
616	    line, msg);
617	err = 1;
618}
619
620
621static void
622catch(int x)
623{
624	unlink(tnam);
625	exit(1);
626}
627
628static void
629crabort(msg)
630char *msg;
631{
632	int sverrno;
633
634	if (strcmp(edtemp, "") != 0) {
635		sverrno = errno;
636		(void) unlink(edtemp);
637		errno = sverrno;
638	}
639	if (tnam != NULL) {
640		sverrno = errno;
641		(void) unlink(tnam);
642		errno = sverrno;
643	}
644	fprintf(stderr, "crontab: %s\n", gettext(msg));
645	exit(1);
646}
647