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      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 #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 <spawn.h>
     49 #include <security/pam_appl.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 
     95 extern int	per_errno;
     96 extern char 	**environ;
     97 
     98 extern int	audit_crontab_modify(char *, char *, int);
     99 extern int	audit_crontab_delete(char *, int);
    100 extern int	audit_crontab_not_allowed(uid_t, char *);
    101 
    102 int		err;
    103 int		cursor;
    104 char		*cf;
    105 char		*tnam;
    106 char		edtemp[5+13+1];
    107 char		line[CTLINESIZE];
    108 static		char	login[UNAMESIZE];
    109 
    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 	uid_t ruid;
    131 	pid_t pid;
    132 	int stat_loc;
    133 	int ret;
    134 	char real_login[UNAMESIZE];
    135 	int tmpfd = -1;
    136 	pam_handle_t *pamh;
    137 	int pam_error;
    138 	pid_t cpid;
    139 	int cstatus;
    140 	char *argvec[3];
    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 			argvec[0] = strdup(editor);
    305 			argvec[1] = strdup(edtemp);
    306 			argvec[2] = NULL;
    307 
    308 			if (argvec[0] == NULL || argvec[1] == NULL)
    309 				crabort("Insufficient memory");
    310 
    311 			sleep(1);
    312 
    313 			while (1) {
    314 				/*
    315 				 * posix_spawnp() allows the file pointed to
    316 				 * by the 'EDITOR' variable to be searched in
    317 				 * the PATH environment variable
    318 				 */
    319 
    320 				ret = posix_spawnp(&cpid, editor, NULL, NULL,
    321 				    (char *const *)argvec,
    322 				    (char *const *)environ);
    323 				if (ret) {
    324 					(void) fprintf(stderr,
    325 					    gettext("crontab: %s: %s\n"),
    326 					    editor, strerror(errno));
    327 					cstatus = -1;
    328 				} else {
    329 					pid_t wpid = 0;
    330 					while ((wpid = waitpid(cpid, &cstatus,
    331 					    0)) == -1 && errno == EINTR)
    332 						;
    333 					if (wpid  == -1)
    334 						cstatus = -1;
    335 				}
    336 
    337 				/* sanity checks */
    338 				if ((tmpfp = fopen(edtemp, "r")) == NULL)
    339 					crabort("can't open temporary file");
    340 				if (fstat(fileno(tmpfp), &stbuf) < 0)
    341 					crabort("can't stat temporary file");
    342 				if (stbuf.st_size == 0)
    343 					crabort("temporary file empty");
    344 				if (omodtime == stbuf.st_mtime) {
    345 					(void) unlink(edtemp);
    346 					fprintf(stderr, gettext(
    347 					    "The crontab file was not"
    348 					    " changed.\n"));
    349 					exit(1);
    350 				}
    351 				if ((cstatus) && (errno != EINTR)) {
    352 					/*
    353 					 * Some editors (like 'vi') can return
    354 					 * a non-zero exit status even though
    355 					 * everything is okay. Need to check.
    356 					 */
    357 					fprintf(stderr, gettext(ED_ERROR));
    358 					fflush(stderr);
    359 					if (isatty(fileno(stdin))) {
    360 						/* Interactive */
    361 						fprintf(stdout,
    362 						    gettext(ED_PROMPT),
    363 						    yesstr, nostr, nostr);
    364 						fflush(stdout);
    365 
    366 						if (yes()) {
    367 							/* Edit again */
    368 							continue;
    369 						} else {
    370 							/* Dump changes */
    371 							(void) unlink(edtemp);
    372 							exit(1);
    373 						}
    374 					} else {
    375 						/*
    376 						 * Non-interactive, dump changes
    377 						 */
    378 						(void) unlink(edtemp);
    379 						exit(1);
    380 					}
    381 				}
    382 				exit(0);
    383 			} /* while (1) */
    384 		}
    385 
    386 		/* fix for 1125555 - ignore common signals while waiting */
    387 		(void) signal(SIGINT, SIG_IGN);
    388 		(void) signal(SIGHUP, SIG_IGN);
    389 		(void) signal(SIGQUIT, SIG_IGN);
    390 		(void) signal(SIGTERM, SIG_IGN);
    391 		wait(&stat_loc);
    392 		if ((stat_loc & 0xFF00) != 0)
    393 			exit(1);
    394 
    395 		/*
    396 		 * unlink edtemp as 'ruid'. The file contents will be held
    397 		 * since we open the file descriptor 'tmpfp' before calling
    398 		 * unlink.
    399 		 */
    400 		if (((ret = seteuid(ruid)) < 0) ||
    401 		    ((tmpfp = fopen(edtemp, "r")) == NULL) ||
    402 		    (unlink(edtemp) == -1)) {
    403 			fprintf(stderr, "crontab: %s: %s\n",
    404 			    edtemp, errmsg(errno));
    405 			if ((ret < 0) || (tmpfp == NULL))
    406 				(void) unlink(edtemp);
    407 			exit(1);
    408 		} else
    409 			seteuid(0);
    410 
    411 		copycron(tmpfp);
    412 	} else {
    413 		if (argc == 0)
    414 			copycron(stdin);
    415 		else if (seteuid(getuid()) != 0 || (fp = fopen(argv[0], "r"))
    416 		    == NULL)
    417 			crabort(BADOPEN);
    418 		else {
    419 			seteuid(0);
    420 			copycron(fp);
    421 		}
    422 	}
    423 	cron_sendmsg(ADD, login, login, CRON);
    424 /*
    425  *	if (per_errno == 2)
    426  *		fprintf(stderr, gettext(WARNSHELL));
    427  */
    428 	return (0);
    429 }
    430 
    431 static void
    432 copycron(fp)
    433 FILE *fp;
    434 {
    435 	FILE *tfp;
    436 	char pid[6], *tnam_end;
    437 	int t;
    438 
    439 	sprintf(pid, "%-5d", getpid());
    440 	tnam = xmalloc(strlen(CRONDIR)+strlen(TMPFILE)+7);
    441 	strcat(strcat(strcat(strcpy(tnam, CRONDIR), "/"), TMPFILE), pid);
    442 	/* cut trailing blanks */
    443 	tnam_end = strchr(tnam, ' ');
    444 	if (tnam_end != NULL)
    445 		*tnam_end = 0;
    446 	/* catch SIGINT, SIGHUP, SIGQUIT signals */
    447 	if (signal(SIGINT, catch) == SIG_IGN)
    448 		signal(SIGINT, SIG_IGN);
    449 	if (signal(SIGHUP, catch) == SIG_IGN) signal(SIGHUP, SIG_IGN);
    450 	if (signal(SIGQUIT, catch) == SIG_IGN) signal(SIGQUIT, SIG_IGN);
    451 	if (signal(SIGTERM, catch) == SIG_IGN) signal(SIGTERM, SIG_IGN);
    452 	if ((t = creat(tnam, CRMODE)) == -1) crabort(BADCREATE);
    453 	if ((tfp = fdopen(t, "w")) == NULL) {
    454 		unlink(tnam);
    455 		crabort(BADCREATE);
    456 	}
    457 	err = 0;	/* if errors found, err set to 1 */
    458 	while (fgets(line, CTLINESIZE, fp) != NULL) {
    459 		cursor = 0;
    460 		while (line[cursor] == ' ' || line[cursor] == '\t')
    461 			cursor++;
    462 		/* fix for 1039689 - treat blank line like a comment */
    463 		if (line[cursor] == '#' || line[cursor] == '\n')
    464 			goto cont;
    465 		if (next_field(0, 59)) continue;
    466 		if (next_field(0, 23)) continue;
    467 		if (next_field(1, 31)) continue;
    468 		if (next_field(1, 12)) continue;
    469 		if (next_field(0, 06)) continue;
    470 		if (line[++cursor] == '\0') {
    471 			cerror(EOLN);
    472 			continue;
    473 		}
    474 cont:
    475 		if (fputs(line, tfp) == EOF) {
    476 			unlink(tnam);
    477 			crabort(BADCREATE);
    478 		}
    479 	}
    480 	fclose(fp);
    481 	fclose(tfp);
    482 
    483 	/* audit differences between old and new crontabs */
    484 	audit_crontab_modify(cf, tnam, err);
    485 
    486 	if (!err) {
    487 		/* make file tfp the new crontab */
    488 		unlink(cf);
    489 		if (link(tnam, cf) == -1) {
    490 			unlink(tnam);
    491 			crabort(BADCREATE);
    492 		}
    493 	} else
    494 		fprintf(stderr, "crontab: %s\n", gettext(ERRSFND));
    495 	unlink(tnam);
    496 }
    497 
    498 static int
    499 next_field(lower, upper)
    500 int lower, upper;
    501 {
    502 	int num, num2;
    503 
    504 	while ((line[cursor] == ' ') || (line[cursor] == '\t')) cursor++;
    505 	if (line[cursor] == '\0') {
    506 		cerror(EOLN);
    507 		return (1);
    508 	}
    509 	if (line[cursor] == '*') {
    510 		cursor++;
    511 		if ((line[cursor] != ' ') && (line[cursor] != '\t')) {
    512 			cerror(UNEXPECT);
    513 			return (1);
    514 		}
    515 		return (0);
    516 	}
    517 	while (TRUE) {
    518 		if (!isdigit(line[cursor])) {
    519 			cerror(UNEXPECT);
    520 			return (1);
    521 		}
    522 		num = 0;
    523 		do {
    524 			num = num*10 + (line[cursor]-'0');
    525 		} while (isdigit(line[++cursor]));
    526 		if ((num < lower) || (num > upper)) {
    527 			cerror(OUTOFBOUND);
    528 			return (1);
    529 		}
    530 		if (line[cursor] == '-') {
    531 			if (!isdigit(line[++cursor])) {
    532 				cerror(UNEXPECT);
    533 				return (1);
    534 			}
    535 			num2 = 0;
    536 			do {
    537 				num2 = num2*10 + (line[cursor]-'0');
    538 			} while (isdigit(line[++cursor]));
    539 			if ((num2 < lower) || (num2 > upper)) {
    540 				cerror(OUTOFBOUND);
    541 				return (1);
    542 			}
    543 		}
    544 		if ((line[cursor] == ' ') || (line[cursor] == '\t')) break;
    545 		if (line[cursor] == '\0') {
    546 			cerror(EOLN);
    547 			return (1);
    548 		}
    549 		if (line[cursor++] != ',') {
    550 			cerror(UNEXPECT);
    551 			return (1);
    552 		}
    553 	}
    554 	return (0);
    555 }
    556 
    557 static void
    558 cerror(msg)
    559 char *msg;
    560 {
    561 	fprintf(stderr, gettext("%scrontab: error on previous line; %s\n"),
    562 	    line, msg);
    563 	err = 1;
    564 }
    565 
    566 
    567 static void
    568 catch(int x)
    569 {
    570 	unlink(tnam);
    571 	exit(1);
    572 }
    573 
    574 static void
    575 crabort(msg)
    576 char *msg;
    577 {
    578 	int sverrno;
    579 
    580 	if (strcmp(edtemp, "") != 0) {
    581 		sverrno = errno;
    582 		(void) unlink(edtemp);
    583 		errno = sverrno;
    584 	}
    585 	if (tnam != NULL) {
    586 		sverrno = errno;
    587 		(void) unlink(tnam);
    588 		errno = sverrno;
    589 	}
    590 	fprintf(stderr, "crontab: %s\n", gettext(msg));
    591 	exit(1);
    592 }
    593