xref: /titanic_52/usr/src/cmd/cron/crontab.c (revision c2580b931007758eab8cb5ae8726ebe1588e259b)
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 
93 extern int	per_errno;
94 
95 extern int	audit_crontab_modify(char *, char *, int);
96 extern int	audit_crontab_delete(char *, int);
97 extern int	audit_crontab_not_allowed(uid_t, char *);
98 
99 int		err;
100 int		cursor;
101 char		*cf;
102 char		*tnam;
103 char		edtemp[5+13+1];
104 char		line[CTLINESIZE];
105 static		char	login[UNAMESIZE];
106 static		char	yeschr;
107 static		char	nochr;
108 
109 static int yes(void);
110 static int next_field(int, int);
111 static void catch(int);
112 static void crabort(char *);
113 static void cerror(char *);
114 static void copycron(FILE *);
115 
116 int
117 main(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 
388 static void
389 copycron(fp)
390 FILE *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 		}
431 cont:
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 
455 static int
456 next_field(lower, upper)
457 int 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 
514 static void
515 cerror(msg)
516 char *msg;
517 {
518 	fprintf(stderr, gettext("%scrontab: error on previous line; %s\n"),
519 	    line, msg);
520 	err = 1;
521 }
522 
523 
524 static void
525 catch(int x)
526 {
527 	unlink(tnam);
528 	exit(1);
529 }
530 
531 static void
532 crabort(msg)
533 char *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 
551 static int
552 yes(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