crontab.c revision 9182:9e3c27050644 
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 2009 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 <security/pam_appl.h>
47#include <limits.h>
48#include <libzoneinfo.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#define	BAD_TZ	"Timezone unrecognized in: %s"
94#define	BAD_SHELL	"Invalid shell specified: %s"
95#define	BAD_HOME	"Unable to access directory: %s\t%s\n"
96
97extern int	per_errno;
98
99extern int	audit_crontab_modify(char *, char *, int);
100extern int	audit_crontab_delete(char *, int);
101extern int	audit_crontab_not_allowed(uid_t, char *);
102
103int		err;
104int		cursor;
105char		*cf;
106char		*tnam;
107char		edtemp[5+13+1];
108char		line[CTLINESIZE];
109static		char	login[UNAMESIZE];
110
111static int	next_field(int, int);
112static void	catch(int);
113static void	crabort(char *);
114static void	cerror(char *);
115static void	copycron(FILE *);
116
117int
118main(int argc, char **argv)
119{
120	int	c, r;
121	int	rflag	= 0;
122	int	lflag	= 0;
123	int	eflag	= 0;
124	int	errflg	= 0;
125	char *pp;
126	FILE *fp, *tmpfp;
127	struct stat stbuf;
128	struct passwd *pwp;
129	time_t omodtime;
130	char *editor;
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	char *buf;
140	size_t buflen;
141
142	(void) setlocale(LC_ALL, "");
143#if !defined(TEXT_DOMAIN)	/* Should be defined by cc -D */
144#define	TEXT_DOMAIN "SYS_TEST"	/* Use this only if it weren't */
145#endif
146	(void) textdomain(TEXT_DOMAIN);
147
148	if (init_yes() < 0) {
149		(void) fprintf(stderr, gettext(ERR_MSG_INIT_YES),
150		    strerror(errno));
151		exit(1);
152	}
153
154	while ((c = getopt(argc, argv, "elr")) != EOF)
155		switch (c) {
156			case 'e':
157				eflag++;
158				break;
159			case 'l':
160				lflag++;
161				break;
162			case 'r':
163				rflag++;
164				break;
165			case '?':
166				errflg++;
167				break;
168		}
169
170	if (eflag + lflag + rflag > 1)
171		errflg++;
172
173	argc -= optind;
174	argv += optind;
175	if (errflg || argc > 1)
176		crabort(BADUSAGE);
177
178	ruid = getuid();
179	if ((pwp = getpwuid(ruid)) == NULL)
180		crabort(INVALIDUSER);
181
182	if (strlcpy(real_login, pwp->pw_name, sizeof (real_login))
183	    >= sizeof (real_login))
184		crabort(NAMETOOLONG);
185
186	if ((eflag || lflag || rflag) && argc == 1) {
187		if ((pwp = getpwnam(*argv)) == NULL)
188			crabort(INVALIDUSER);
189
190		if (!chkauthattr(CRONADMIN_AUTH, real_login)) {
191			if (pwp->pw_uid != ruid)
192				crabort(NOTROOT);
193			else
194				pp = getuser(ruid);
195		} else
196			pp = *argv++;
197	} else {
198		pp = getuser(ruid);
199	}
200
201	if (pp == NULL) {
202		if (per_errno == 2)
203			crabort(BADSHELL);
204		else
205			crabort(INVALIDUSER);
206	}
207	if (strlcpy(login, pp, sizeof (login)) >= sizeof (login))
208		crabort(NAMETOOLONG);
209	if (!allowed(login, CRONALLOW, CRONDENY))
210		crabort(NOTALLOWED);
211
212	/* Do account validation check */
213	pam_error = pam_start("cron", pp, NULL, &pamh);
214	if (pam_error != PAM_SUCCESS) {
215		crabort((char *)pam_strerror(pamh, pam_error));
216	}
217	pam_error = pam_acct_mgmt(pamh, PAM_SILENT);
218	if (pam_error != PAM_SUCCESS) {
219		(void) fprintf(stderr, gettext("Warning - Invalid account: "
220		    "'%s' not allowed to execute cronjobs\n"), pp);
221	}
222	(void) pam_end(pamh, PAM_SUCCESS);
223
224
225	/* check for unaudited shell */
226	if (audit_crontab_not_allowed(ruid, pp))
227		crabort(AUDITREJECT);
228
229	cf = xmalloc(strlen(CRONDIR)+strlen(login)+2);
230	strcat(strcat(strcpy(cf, CRONDIR), "/"), login);
231
232	if (rflag) {
233		r = unlink(cf);
234		cron_sendmsg(DELETE, login, login, CRON);
235		audit_crontab_delete(cf, r);
236		exit(0);
237	}
238	if (lflag) {
239		if ((fp = fopen(cf, "r")) == NULL)
240			crabort(BADOPEN);
241		while (fgets(line, CTLINESIZE, fp) != NULL)
242			fputs(line, stdout);
243		fclose(fp);
244		exit(0);
245	}
246	if (eflag) {
247		if ((fp = fopen(cf, "r")) == NULL) {
248			if (errno != ENOENT)
249				crabort(BADOPEN);
250		}
251		(void) strcpy(edtemp, "/tmp/crontabXXXXXX");
252		tmpfd = mkstemp(edtemp);
253		if (fchown(tmpfd, ruid, -1) == -1) {
254			(void) close(tmpfd);
255			crabort("fchown of temporary file failed");
256		}
257		(void) close(tmpfd);
258		/*
259		 * Fork off a child with user's permissions,
260		 * to edit the crontab file
261		 */
262		if ((pid = fork()) == (pid_t)-1)
263			crabort("fork failed");
264		if (pid == 0) {		/* child process */
265			/* give up super-user privileges. */
266			setuid(ruid);
267			if ((tmpfp = fopen(edtemp, "w")) == NULL)
268				crabort("can't create temporary file");
269			if (fp != NULL) {
270				/*
271				 * Copy user's crontab file to temporary file.
272				 */
273				while (fgets(line, CTLINESIZE, fp) != NULL) {
274					fputs(line, tmpfp);
275					if (ferror(tmpfp)) {
276						fclose(fp);
277						fclose(tmpfp);
278						crabort("write error on"
279						    "temporary file");
280					}
281				}
282				if (ferror(fp)) {
283					fclose(fp);
284					fclose(tmpfp);
285					crabort(BADREAD);
286				}
287				fclose(fp);
288			}
289			if (fclose(tmpfp) == EOF)
290				crabort("write error on temporary file");
291			if (stat(edtemp, &stbuf) < 0)
292				crabort("can't stat temporary file");
293			omodtime = stbuf.st_mtime;
294#ifdef _XPG_NOTDEFINED
295			editor = getenv("VISUAL");
296			if (editor == NULL) {
297#endif
298				editor = getenv("EDITOR");
299				if (editor == NULL)
300					editor = VIPATH;
301#ifdef _XPG_NOTDEFINED
302			}
303#endif
304			buflen = strlen(editor) + strlen(edtemp) + 2;
305			buf = xmalloc(buflen);
306			(void) snprintf(buf, buflen, "%s %s", editor, edtemp);
307
308			sleep(1);
309
310			while (1) {
311				ret = system(buf);
312
313				/* sanity checks */
314				if ((tmpfp = fopen(edtemp, "r")) == NULL)
315					crabort("can't open temporary file");
316				if (fstat(fileno(tmpfp), &stbuf) < 0)
317					crabort("can't stat temporary file");
318				if (stbuf.st_size == 0)
319					crabort("temporary file empty");
320				if (omodtime == stbuf.st_mtime) {
321					(void) unlink(edtemp);
322					fprintf(stderr, gettext(
323					    "The crontab file was not"
324					    " changed.\n"));
325					exit(1);
326				}
327				if ((ret) && (errno != EINTR)) {
328					/*
329					 * Some editors (like 'vi') can return
330					 * a non-zero exit status even though
331					 * everything is okay. Need to check.
332					 */
333					fprintf(stderr, gettext(ED_ERROR));
334					fflush(stderr);
335					if (isatty(fileno(stdin))) {
336						/* Interactive */
337						fprintf(stdout,
338						    gettext(ED_PROMPT),
339						    yesstr, nostr, nostr);
340						fflush(stdout);
341
342						if (yes()) {
343							/* Edit again */
344							continue;
345						} else {
346							/* Dump changes */
347							(void) unlink(edtemp);
348							exit(1);
349						}
350					} else {
351						/*
352						 * Non-interactive, dump changes
353						 */
354						(void) unlink(edtemp);
355						exit(1);
356					}
357				}
358				exit(0);
359			} /* while (1) */
360		}
361
362		/* fix for 1125555 - ignore common signals while waiting */
363		(void) signal(SIGINT, SIG_IGN);
364		(void) signal(SIGHUP, SIG_IGN);
365		(void) signal(SIGQUIT, SIG_IGN);
366		(void) signal(SIGTERM, SIG_IGN);
367		wait(&stat_loc);
368		if ((stat_loc & 0xFF00) != 0)
369			exit(1);
370
371		/*
372		 * unlink edtemp as 'ruid'. The file contents will be held
373		 * since we open the file descriptor 'tmpfp' before calling
374		 * unlink.
375		 */
376		if (((ret = seteuid(ruid)) < 0) ||
377		    ((tmpfp = fopen(edtemp, "r")) == NULL) ||
378		    (unlink(edtemp) == -1)) {
379			fprintf(stderr, "crontab: %s: %s\n",
380			    edtemp, errmsg(errno));
381			if ((ret < 0) || (tmpfp == NULL))
382				(void) unlink(edtemp);
383			exit(1);
384		} else
385			seteuid(0);
386
387		copycron(tmpfp);
388	} else {
389		if (argc == 0)
390			copycron(stdin);
391		else if (seteuid(getuid()) != 0 || (fp = fopen(argv[0], "r"))
392		    == NULL)
393			crabort(BADOPEN);
394		else {
395			seteuid(0);
396			copycron(fp);
397		}
398	}
399	cron_sendmsg(ADD, login, login, CRON);
400/*
401 *	if (per_errno == 2)
402 *		fprintf(stderr, gettext(WARNSHELL));
403 */
404	return (0);
405}
406
407static void
408copycron(fp)
409FILE *fp;
410{
411	FILE *tfp;
412	char pid[6], *tnam_end;
413	int t;
414	char buf[LINE_MAX];
415
416	sprintf(pid, "%-5d", getpid());
417	tnam = xmalloc(strlen(CRONDIR)+strlen(TMPFILE)+7);
418	strcat(strcat(strcat(strcpy(tnam, CRONDIR), "/"), TMPFILE), pid);
419	/* cut trailing blanks */
420	tnam_end = strchr(tnam, ' ');
421	if (tnam_end != NULL)
422		*tnam_end = 0;
423	/* catch SIGINT, SIGHUP, SIGQUIT signals */
424	if (signal(SIGINT, catch) == SIG_IGN)
425		signal(SIGINT, SIG_IGN);
426	if (signal(SIGHUP, catch) == SIG_IGN) signal(SIGHUP, SIG_IGN);
427	if (signal(SIGQUIT, catch) == SIG_IGN) signal(SIGQUIT, SIG_IGN);
428	if (signal(SIGTERM, catch) == SIG_IGN) signal(SIGTERM, SIG_IGN);
429	if ((t = creat(tnam, CRMODE)) == -1) crabort(BADCREATE);
430	if ((tfp = fdopen(t, "w")) == NULL) {
431		unlink(tnam);
432		crabort(BADCREATE);
433	}
434	err = 0;	/* if errors found, err set to 1 */
435	while (fgets(line, CTLINESIZE, fp) != NULL) {
436		cursor = 0;
437		while (line[cursor] == ' ' || line[cursor] == '\t')
438			cursor++;
439		/* fix for 1039689 - treat blank line like a comment */
440		if (line[cursor] == '#' || line[cursor] == '\n')
441			goto cont;
442
443		if (strncmp(&line[cursor], ENV_TZ, strlen(ENV_TZ)) == 0) {
444			char *x;
445
446			strncpy(buf, &line[cursor + strlen(ENV_TZ)],
447			    sizeof (buf));
448			if ((x = strchr(buf, '\n')) != NULL)
449				*x = NULL;
450
451			if (isvalid_tz(buf, NULL, _VTZ_ALL)) {
452				goto cont;
453			} else {
454				err = 1;
455				fprintf(stderr, BAD_TZ, &line[cursor]);
456				continue;
457			}
458		} else if (strncmp(&line[cursor], ENV_SHELL,
459		    strlen(ENV_SHELL)) == 0) {
460			char *x;
461
462			strncpy(buf, &line[cursor + strlen(ENV_SHELL)],
463			    sizeof (buf));
464			if ((x = strchr(buf, '\n')) != NULL)
465				*x = NULL;
466
467			if (isvalid_shell(buf)) {
468				goto cont;
469			} else {
470				err = 1;
471				fprintf(stderr, BAD_SHELL, &line[cursor]);
472				continue;
473			}
474		} else if (strncmp(&line[cursor], ENV_HOME,
475		    strlen(ENV_HOME)) == 0) {
476			char *x;
477
478			strncpy(buf, &line[cursor + strlen(ENV_HOME)],
479			    sizeof (buf));
480			if ((x = strchr(buf, '\n')) != NULL)
481				*x = NULL;
482			if (chdir(buf) == 0) {
483				goto cont;
484			} else {
485				err = 1;
486				fprintf(stderr, BAD_HOME, &line[cursor],
487				    strerror(errno));
488				continue;
489			}
490		}
491
492		if (next_field(0, 59)) continue;
493		if (next_field(0, 23)) continue;
494		if (next_field(1, 31)) continue;
495		if (next_field(1, 12)) continue;
496		if (next_field(0, 06)) continue;
497		if (line[++cursor] == '\0') {
498			cerror(EOLN);
499			continue;
500		}
501cont:
502		if (fputs(line, tfp) == EOF) {
503			unlink(tnam);
504			crabort(BADCREATE);
505		}
506	}
507	fclose(fp);
508	fclose(tfp);
509
510	/* audit differences between old and new crontabs */
511	audit_crontab_modify(cf, tnam, err);
512
513	if (!err) {
514		/* make file tfp the new crontab */
515		unlink(cf);
516		if (link(tnam, cf) == -1) {
517			unlink(tnam);
518			crabort(BADCREATE);
519		}
520	} else {
521		crabort(ERRSFND);
522	}
523	unlink(tnam);
524}
525
526static int
527next_field(lower, upper)
528int lower, upper;
529{
530	int num, num2;
531
532	while ((line[cursor] == ' ') || (line[cursor] == '\t')) cursor++;
533	if (line[cursor] == '\0') {
534		cerror(EOLN);
535		return (1);
536	}
537	if (line[cursor] == '*') {
538		cursor++;
539		if ((line[cursor] != ' ') && (line[cursor] != '\t')) {
540			cerror(UNEXPECT);
541			return (1);
542		}
543		return (0);
544	}
545	while (TRUE) {
546		if (!isdigit(line[cursor])) {
547			cerror(UNEXPECT);
548			return (1);
549		}
550		num = 0;
551		do {
552			num = num*10 + (line[cursor]-'0');
553		} while (isdigit(line[++cursor]));
554		if ((num < lower) || (num > upper)) {
555			cerror(OUTOFBOUND);
556			return (1);
557		}
558		if (line[cursor] == '-') {
559			if (!isdigit(line[++cursor])) {
560				cerror(UNEXPECT);
561				return (1);
562			}
563			num2 = 0;
564			do {
565				num2 = num2*10 + (line[cursor]-'0');
566			} while (isdigit(line[++cursor]));
567			if ((num2 < lower) || (num2 > upper)) {
568				cerror(OUTOFBOUND);
569				return (1);
570			}
571		}
572		if ((line[cursor] == ' ') || (line[cursor] == '\t')) break;
573		if (line[cursor] == '\0') {
574			cerror(EOLN);
575			return (1);
576		}
577		if (line[cursor++] != ',') {
578			cerror(UNEXPECT);
579			return (1);
580		}
581	}
582	return (0);
583}
584
585static void
586cerror(msg)
587char *msg;
588{
589	fprintf(stderr, gettext("%scrontab: error on previous line; %s\n"),
590	    line, msg);
591	err = 1;
592}
593
594
595static void
596catch(int x)
597{
598	unlink(tnam);
599	exit(1);
600}
601
602static void
603crabort(msg)
604char *msg;
605{
606	int sverrno;
607
608	if (strcmp(edtemp, "") != 0) {
609		sverrno = errno;
610		(void) unlink(edtemp);
611		errno = sverrno;
612	}
613	if (tnam != NULL) {
614		sverrno = errno;
615		(void) unlink(tnam);
616		errno = sverrno;
617	}
618	fprintf(stderr, "crontab: %s\n", gettext(msg));
619	exit(1);
620}
621