xref: /netbsd-src/usr.bin/su/su.c (revision 1c9b56c830954ccf3b57004ac65562e3d6afacf6)
1 /*	$NetBSD: su.c,v 1.64 2005/01/10 03:11:50 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1988 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT(
35     "@(#) Copyright (c) 1988 The Regents of the University of California.\n\
36  All rights reserved.\n");
37 #endif /* not lint */
38 
39 #ifndef lint
40 #if 0
41 static char sccsid[] = "@(#)su.c	8.3 (Berkeley) 4/2/94";*/
42 #else
43 __RCSID("$NetBSD: su.c,v 1.64 2005/01/10 03:11:50 christos Exp $");
44 #endif
45 #endif /* not lint */
46 
47 #include <sys/param.h>
48 #include <sys/time.h>
49 #include <sys/resource.h>
50 #include <err.h>
51 #include <errno.h>
52 #include <grp.h>
53 #include <paths.h>
54 #include <pwd.h>
55 #include <stdio.h>
56 #ifdef SKEY
57 #include <skey.h>
58 #endif
59 #include <stdlib.h>
60 #include <string.h>
61 #include <syslog.h>
62 #include <time.h>
63 #include <tzfile.h>
64 #include <unistd.h>
65 
66 #ifdef LOGIN_CAP
67 #include <login_cap.h>
68 #endif
69 
70 #ifdef KERBEROS
71 #include <des.h>
72 #include <krb.h>
73 #include <netdb.h>
74 
75 static int kerberos(char *, char *, int);
76 static int koktologin(char *, char *, char *);
77 
78 #endif
79 
80 #ifdef KERBEROS5
81 #include <krb5.h>
82 
83 static int kerberos5(char *, char *, int);
84 
85 #endif
86 
87 #if defined(KERBEROS) || defined(KERBEROS5)
88 
89 #define	ARGSTRX	"-Kdflm"
90 
91 int use_kerberos = 1;
92 
93 #else
94 #define	ARGSTRX	"-dflm"
95 #endif
96 
97 #ifndef	SU_GROUP
98 #define	SU_GROUP	"wheel"
99 #endif
100 
101 #ifdef LOGIN_CAP
102 #define ARGSTR	ARGSTRX "c:"
103 #else
104 #define ARGSTR ARGSTRX
105 #endif
106 
107 static int chshell(const char *);
108 static char *ontty(void);
109 static int check_ingroup(int, const char *, const char *, int);
110 
111 int main(int, char **);
112 
113 int
114 main(int argc, char **argv)
115 {
116 	extern char **environ;
117 	struct passwd *pwd;
118 	char *p;
119 #ifdef BSD4_4
120 	struct timeval tp;
121 #endif
122 	uid_t ruid;
123 	int asme, ch, asthem, fastlogin, prio, gohome;
124 	enum { UNSET, YES, NO } iscsh = UNSET;
125 	char *user, *shell, *avshell, *username, **np;
126 	char *userpass, *class;
127 	char shellbuf[MAXPATHLEN], avshellbuf[MAXPATHLEN];
128 	time_t pw_warntime = _PASSWORD_WARNDAYS * SECSPERDAY;
129 #ifdef LOGIN_CAP
130 	login_cap_t *lc;
131 #endif
132 
133 	asme = asthem = fastlogin = 0;
134 	gohome = 1;
135 	shell = class = NULL;
136 	while ((ch = getopt(argc, argv, ARGSTR)) != -1)
137 		switch((char)ch) {
138 #if defined(KERBEROS) || defined(KERBEROS5)
139 		case 'K':
140 			use_kerberos = 0;
141 			break;
142 #endif
143 #ifdef LOGIN_CAP
144 		case 'c':
145 			class = optarg;
146 			break;
147 #endif
148 		case 'd':
149 			asme = 0;
150 			asthem = 1;
151 			gohome = 0;
152 			break;
153 		case 'f':
154 			fastlogin = 1;
155 			break;
156 		case '-':
157 		case 'l':
158 			asme = 0;
159 			asthem = 1;
160 			break;
161 		case 'm':
162 			asme = 1;
163 			asthem = 0;
164 			break;
165 		case '?':
166 		default:
167 			(void)fprintf(stderr,
168 			    "usage: %s [%s] [login [shell arguments]]\n",
169 			    getprogname(), ARGSTR);
170 			exit(1);
171 		}
172 	argv += optind;
173 
174 	/* Lower the priority so su runs faster */
175 	errno = 0;
176 	prio = getpriority(PRIO_PROCESS, 0);
177 	if (errno)
178 		prio = 0;
179 	if (prio > -2)
180 		(void)setpriority(PRIO_PROCESS, 0, -2);
181 	openlog("su", 0, LOG_AUTH);
182 
183 	/* get current login name and shell */
184 	ruid = getuid();
185 	username = getlogin();
186 	if (username == NULL || (pwd = getpwnam(username)) == NULL ||
187 	    pwd->pw_uid != ruid)
188 		pwd = getpwuid(ruid);
189 	if (pwd == NULL)
190 		errx(1, "who are you?");
191 	username = strdup(pwd->pw_name);
192 	userpass = strdup(pwd->pw_passwd);
193 	if (username == NULL || userpass == NULL)
194 		err(1, "strdup");
195 
196 
197 	if (asme) {
198 		if (pwd->pw_shell && *pwd->pw_shell) {
199 			strlcpy(shellbuf, pwd->pw_shell, sizeof(shellbuf));
200 			shell = shellbuf;
201 		} else {
202 			shell = _PATH_BSHELL;
203 			iscsh = NO;
204 		}
205 	}
206 	/* get target login information, default to root */
207 	user = *argv ? *argv : "root";
208 	np = *argv ? argv : argv-1;
209 
210 	if ((pwd = getpwnam(user)) == NULL)
211 		errx(1, "unknown login %s", user);
212 
213 #ifdef LOGIN_CAP
214 	/* force the usage of specified class */
215 	if (class) {
216 		if (ruid)
217 			errx(1, "Only root may use -c");
218 
219 		pwd->pw_class = class;
220 	}
221 	if ((lc = login_getclass(pwd->pw_class)) == NULL)
222 		errx(1, "Unknown class %s\n", pwd->pw_class);
223 
224 	pw_warntime = login_getcaptime(lc, "password-warn",
225                                     _PASSWORD_WARNDAYS * SECSPERDAY,
226                                     _PASSWORD_WARNDAYS * SECSPERDAY);
227 #endif
228 
229 	if (ruid
230 #ifdef KERBEROS5
231 	    && (!use_kerberos || kerberos5(username, user, pwd->pw_uid))
232 #endif
233 #ifdef KERBEROS
234 	    && (!use_kerberos || kerberos(username, user, pwd->pw_uid))
235 #endif
236 	    ) {
237 		char *pass = pwd->pw_passwd;
238 		int ok = pwd->pw_uid != 0;
239 
240 #ifdef SU_ROOTAUTH
241 		/*
242 		 * Allow those in group rootauth to su to root, by supplying
243 		 * their own password.
244 		 */
245 		if (!ok) {
246 			if ((ok = check_ingroup(-1, SU_ROOTAUTH, username, 0))) {
247 				pass = userpass;
248 				user = username;
249 			}
250 		}
251 #endif
252 		/*
253 		 * Only allow those in group SU_GROUP to su to root,
254 		 * but only if that group has any members.
255 		 * If SU_GROUP has no members, allow anyone to su root
256 		 */
257 		if (!ok) {
258 			ok = check_ingroup(-1, SU_GROUP, username, 1);
259 		}
260 		if (!ok)
261 			errx(1,
262 	    "you are not listed in the correct secondary group (%s) to su %s.",
263 					    SU_GROUP, user);
264 		/* if target requires a password, verify it */
265 		if (*pass) {
266 			p = getpass("Password:");
267 #ifdef SKEY
268 			if (strcasecmp(p, "s/key") == 0) {
269 				if (skey_haskey(user))
270 					errx(1, "Sorry, you have no s/key.");
271 				else {
272 					if (skey_authenticate(user)) {
273 						goto badlogin;
274 					}
275 				}
276 
277 			} else
278 #endif
279 			if (strcmp(pass, crypt(p, pass))) {
280 #ifdef SKEY
281 badlogin:
282 #endif
283 				fprintf(stderr, "Sorry\n");
284 				syslog(LOG_WARNING,
285 					"BAD SU %s to %s%s", username,
286 					pwd->pw_name, ontty());
287 				exit(1);
288 			}
289 		}
290 	}
291 
292 	if (asme) {
293 		/* if asme and non-standard target shell, must be root */
294 		if (!chshell(pwd->pw_shell) && ruid)
295 			errx(1,"permission denied (shell).");
296 	} else if (pwd->pw_shell && *pwd->pw_shell) {
297 		shell = pwd->pw_shell;
298 		iscsh = UNSET;
299 	} else {
300 		shell = _PATH_BSHELL;
301 		iscsh = NO;
302 	}
303 
304 	if ((p = strrchr(shell, '/')) != NULL)
305 		avshell = p+1;
306 	else
307 		avshell = shell;
308 
309 	/* if we're forking a csh, we want to slightly muck the args */
310 	if (iscsh == UNSET)
311 		iscsh = strstr(avshell, "csh") ? YES : NO;
312 
313 	/* set permissions */
314 #ifdef LOGIN_CAP
315 	if (setusercontext(lc, pwd, pwd->pw_uid,
316 	    (asthem ? (LOGIN_SETPRIORITY | LOGIN_SETUMASK) : 0) |
317 	    LOGIN_SETRESOURCES | LOGIN_SETGROUP | LOGIN_SETUSER))
318 		err(1, "setting user context");
319 #else
320 	if (setgid(pwd->pw_gid) < 0)
321 		err(1, "setgid");
322 	if (initgroups(user, pwd->pw_gid))
323 		errx(1, "initgroups failed");
324 	if (setuid(pwd->pw_uid) < 0)
325 		err(1, "setuid");
326 #endif
327 
328 	if (!asme) {
329 		if (asthem) {
330 			p = getenv("TERM");
331 			/* Create an empty environment */
332 			if ((environ = malloc(sizeof(char *))) == NULL)
333 				err(1, NULL);
334 			environ[0] = NULL;
335 #ifdef LOGIN_CAP
336 			if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETPATH))
337 				err(1, "setting user context");
338 #else
339 			(void)setenv("PATH", _PATH_DEFPATH, 1);
340 #endif
341 			if (p)
342 				(void)setenv("TERM", p, 1);
343 			if (gohome && chdir(pwd->pw_dir) < 0)
344 				errx(1, "no directory");
345 		}
346 
347 		if (asthem || pwd->pw_uid)
348 			(void)setenv("USER", pwd->pw_name, 1);
349 		(void)setenv("HOME", pwd->pw_dir, 1);
350 		(void)setenv("SHELL", shell, 1);
351 	}
352 	(void)setenv("SU_FROM", username, 1);
353 
354 	if (iscsh == YES) {
355 		if (fastlogin)
356 			*np-- = "-f";
357 		if (asme)
358 			*np-- = "-m";
359 	} else {
360 		if (fastlogin)
361 			unsetenv("ENV");
362 	}
363 
364 	if (asthem) {
365 		avshellbuf[0] = '-';
366 		(void)strlcpy(avshellbuf+1, avshell, sizeof(avshellbuf) - 1);
367 		avshell = avshellbuf;
368 	} else if (iscsh == YES) {
369 		/* csh strips the first character... */
370 		avshellbuf[0] = '_';
371 		(void)strlcpy(avshellbuf+1, avshell, sizeof(avshellbuf) - 1);
372 		avshell = avshellbuf;
373 	}
374 	*np = avshell;
375 
376 #ifdef BSD4_4
377 	if (pwd->pw_change || pwd->pw_expire)
378 		(void)gettimeofday(&tp, (struct timezone *)NULL);
379 	if (pwd->pw_change) {
380 		if (tp.tv_sec >= pwd->pw_change) {
381 			(void)printf("%s -- %s's password has expired.\n",
382 				     (ruid ? "Sorry" : "Note"), user);
383 			if (ruid != 0)
384 				exit(1);
385 		} else if (pwd->pw_change - tp.tv_sec < pw_warntime)
386 			(void)printf("Warning: %s's password expires on %s",
387 				     user, ctime(&pwd->pw_change));
388 	}
389 	if (pwd->pw_expire) {
390 		if (tp.tv_sec >= pwd->pw_expire) {
391 			(void)printf("%s -- %s's account has expired.\n",
392 				     (ruid ? "Sorry" : "Note"), user);
393 			if (ruid != 0)
394 				exit(1);
395 		} else if (pwd->pw_expire - tp.tv_sec <
396 		    _PASSWORD_WARNDAYS * SECSPERDAY)
397 			(void)printf("Warning: %s's account expires on %s",
398 				     user, ctime(&pwd->pw_expire));
399  	}
400 #endif
401 	if (ruid != 0)
402 		syslog(LOG_NOTICE, "%s to %s%s",
403 		    username, pwd->pw_name, ontty());
404 
405 	/* Raise our priority back to what we had before */
406 	(void)setpriority(PRIO_PROCESS, 0, prio);
407 
408 	execv(shell, np);
409 	err(1, "%s", shell);
410         /* NOTREACHED */
411 }
412 
413 
414 static int
415 chshell(const char *sh)
416 {
417 	const char *cp;
418 
419 	setusershell();
420 	while ((cp = getusershell()) != NULL)
421 		if (!strcmp(cp, sh))
422 			return 1;
423 	return 0;
424 }
425 
426 static char *
427 ontty(void)
428 {
429 	char *p;
430 	static char buf[MAXPATHLEN + 4];
431 
432 	buf[0] = 0;
433 	if ((p = ttyname(STDERR_FILENO)) != NULL)
434 		(void)snprintf(buf, sizeof buf, " on %s", p);
435 	return buf;
436 }
437 
438 #ifdef KERBEROS5
439 static int
440 kerberos5(char *username, char *user, int uid)
441 {
442 	krb5_error_code ret;
443 	krb5_context context;
444 	krb5_principal princ = NULL;
445 	krb5_ccache ccache, ccache2;
446 	char *cc_name;
447 	const char *filename;
448 
449 	ret = krb5_init_context(&context);
450 	if (ret)
451 		return (1);
452 
453 	if (strcmp (user, "root") == 0)
454 		ret = krb5_make_principal(context, &princ,
455 					  NULL, username, "root", NULL);
456 	else
457 		ret = krb5_make_principal(context, &princ,
458 					  NULL, user, NULL);
459 	if (ret)
460 		goto fail;
461 	if (!krb5_kuserok(context, princ, user) && !uid) {
462 		warnx ("kerberos5: not in %s's ACL.", user);
463 		goto fail;
464 	}
465 	ret = krb5_cc_gen_new(context, &krb5_mcc_ops, &ccache);
466 	if (ret)
467 		goto fail;
468 	ret = krb5_verify_user_lrealm(context, princ, ccache, NULL, TRUE,
469 				      NULL);
470 	if (ret) {
471 		krb5_cc_destroy(context, ccache);
472 		switch (ret) {
473 		case KRB5_LIBOS_PWDINTR :
474 			break;
475 		case KRB5KRB_AP_ERR_BAD_INTEGRITY:
476 		case KRB5KRB_AP_ERR_MODIFIED:
477 			krb5_warnx(context, "Password incorrect");
478 			break;
479 		default :
480 			krb5_warn(context, ret, "krb5_verify_user");
481 			break;
482 		}
483 		goto fail;
484 	}
485 	ret = krb5_cc_gen_new(context, &krb5_fcc_ops, &ccache2);
486 	if (ret) {
487 		krb5_cc_destroy(context, ccache);
488 		goto fail;
489 	}
490 	ret = krb5_cc_copy_cache(context, ccache, ccache2);
491 	if (ret) {
492 		krb5_cc_destroy(context, ccache);
493 		krb5_cc_destroy(context, ccache2);
494 		goto fail;
495 	}
496 
497 	filename = krb5_cc_get_name(context, ccache2);
498 	asprintf(&cc_name, "%s:%s", krb5_cc_get_type(context, ccache2),
499 		 filename);
500 	if (chown (filename, uid, -1) < 0) {
501 		warn("chown %s", filename);
502 		free(cc_name);
503 		krb5_cc_destroy(context, ccache);
504 		krb5_cc_destroy(context, ccache2);
505 		goto fail;
506 	}
507 
508 	setenv("KRB5CCNAME", cc_name, 1);
509 	free(cc_name);
510 	krb5_cc_close(context, ccache2);
511 	krb5_cc_destroy(context, ccache);
512 	return (0);
513 
514  fail:
515 	if (princ != NULL)
516 		krb5_free_principal (context, princ);
517 	krb5_free_context (context);
518 	return (1);
519 }
520 #endif
521 
522 #ifdef KERBEROS
523 static int
524 kerberos(char *username, char *user, int uid)
525 {
526 	KTEXT_ST ticket;
527 	AUTH_DAT authdata;
528 	struct hostent *hp;
529 	int kerno;
530 	u_long faddr;
531 	char lrealm[REALM_SZ], krbtkfile[MAXPATHLEN];
532 	char hostname[MAXHOSTNAMELEN + 1], savehost[MAXHOSTNAMELEN + 1];
533 
534 	if (krb_get_lrealm(lrealm, 1) != KSUCCESS)
535 		return (1);
536 	if (koktologin(username, lrealm, user) && !uid) {
537 		warnx("kerberos: not in %s's ACL.", user);
538 		return (1);
539 	}
540 	(void)snprintf(krbtkfile, sizeof krbtkfile, "%s_%s_%d", TKT_ROOT,
541 	    user, getuid());
542 
543 	(void)setenv("KRBTKFILE", krbtkfile, 1);
544 	(void)krb_set_tkt_string(krbtkfile);
545 	/*
546 	 * Set real as well as effective ID to 0 for the moment,
547 	 * to make the kerberos library do the right thing.
548 	 */
549 	if (setuid(0) < 0) {
550 		warn("setuid");
551 		return (1);
552 	}
553 
554 	/*
555 	 * Little trick here -- if we are su'ing to root,
556 	 * we need to get a ticket for "xxx.root", where xxx represents
557 	 * the name of the person su'ing.  Otherwise (non-root case),
558 	 * we need to get a ticket for "yyy.", where yyy represents
559 	 * the name of the person being su'd to, and the instance is null
560 	 *
561 	 * We should have a way to set the ticket lifetime,
562 	 * with a system default for root.
563 	 */
564 	{
565 		char prompt[128];
566 		char passw[256];
567 
568 		(void)snprintf (prompt, sizeof(prompt),
569 			  "%s's Password: ",
570 			  krb_unparse_name_long ((uid == 0 ? username : user),
571 						 (uid == 0 ? "root" : ""),
572 						 lrealm));
573 		if (des_read_pw_string (passw, sizeof (passw), prompt, 0)) {
574 			memset (passw, 0, sizeof (passw));
575 			return (1);
576 		}
577 		if (strlen(passw) == 0)
578 			return (1); /* Empty passwords are not allowed */
579 
580 		kerno = krb_get_pw_in_tkt((uid == 0 ? username : user),
581 					  (uid == 0 ? "root" : ""), lrealm,
582 					  KRB_TICKET_GRANTING_TICKET,
583 					  lrealm,
584 					  DEFAULT_TKT_LIFE,
585 					  passw);
586 		memset (passw, 0, strlen (passw));
587 	}
588 
589 	if (kerno != KSUCCESS) {
590 		if (kerno == KDC_PR_UNKNOWN) {
591 			warnx("kerberos: principal unknown: %s.%s@%s",
592 				(uid == 0 ? username : user),
593 				(uid == 0 ? "root" : ""), lrealm);
594 			return (1);
595 		}
596 		warnx("kerberos: unable to su: %s", krb_err_txt[kerno]);
597 		syslog(LOG_WARNING,
598 		    "BAD Kerberos SU: %s to %s%s: %s",
599 		    username, user, ontty(), krb_err_txt[kerno]);
600 		return (1);
601 	}
602 
603 	if (chown(krbtkfile, uid, -1) < 0) {
604 		warn("chown");
605 		(void)unlink(krbtkfile);
606 		return (1);
607 	}
608 
609 	(void)setpriority(PRIO_PROCESS, 0, -2);
610 
611 	if (gethostname(hostname, sizeof(hostname)) == -1) {
612 		warn("gethostname");
613 		dest_tkt();
614 		return (1);
615 	}
616 	hostname[sizeof(hostname) - 1] = '\0';
617 
618 	(void)strlcpy(savehost, krb_get_phost(hostname), sizeof(savehost));
619 	savehost[sizeof(savehost) - 1] = '\0';
620 
621 	kerno = krb_mk_req(&ticket, "rcmd", savehost, lrealm, 33);
622 
623 	if (kerno == KDC_PR_UNKNOWN) {
624 		warnx("Warning: TGT not verified.");
625 		syslog(LOG_WARNING,
626 		    "%s to %s%s, TGT not verified (%s); %s.%s not registered?",
627 		    username, user, ontty(), krb_err_txt[kerno],
628 		    "rcmd", savehost);
629 	} else if (kerno != KSUCCESS) {
630 		warnx("Unable to use TGT: %s", krb_err_txt[kerno]);
631 		syslog(LOG_WARNING, "failed su: %s to %s%s: %s",
632 		    username, user, ontty(), krb_err_txt[kerno]);
633 		dest_tkt();
634 		return (1);
635 	} else {
636 		if (!(hp = gethostbyname(hostname))) {
637 			warnx("can't get addr of %s", hostname);
638 			dest_tkt();
639 			return (1);
640 		}
641 		memmove((char *)&faddr, (char *)hp->h_addr, sizeof(faddr));
642 
643 		if ((kerno = krb_rd_req(&ticket, "rcmd", savehost, faddr,
644 		    &authdata, "")) != KSUCCESS) {
645 			warnx("kerberos: unable to verify rcmd ticket: %s",
646 			    krb_err_txt[kerno]);
647 			syslog(LOG_WARNING,
648 			    "failed su: %s to %s%s: %s", username,
649 			     user, ontty(), krb_err_txt[kerno]);
650 			dest_tkt();
651 			return (1);
652 		}
653 	}
654 	return (0);
655 }
656 
657 static int
658 koktologin(char *name, char *realm, char *toname)
659 {
660 	return krb_kuserok(name,
661 			   strcmp (toname, "root") == 0 ? "root" : "",
662 			   realm,
663 			   toname);
664 }
665 #endif
666 
667 static int
668 check_ingroup (int gid, const char *gname, const char *user, int ifempty)
669 {
670 	struct group *gr;
671 	char **g;
672 #ifdef SU_INDIRECT_GROUP
673 	char **gr_mem;
674 	int n = 0;
675 	int i = 0;
676 #endif
677 	int ok = 0;
678 
679 	if (gname == NULL)
680 		gr = getgrgid((gid_t) gid);
681 	else
682 		gr = getgrnam(gname);
683 
684 	/*
685 	 * XXX we are relying on the fact that we only set ifempty when
686 	 * calling to check for SU_GROUP and that is the only time a
687 	 * missing group is acceptable.
688 	 */
689 	if (gr == NULL)
690 		return ifempty;
691 	if (!*gr->gr_mem)		/* empty */
692 		return ifempty;
693 
694 	/*
695 	 * Ok, first see if user is in gr_mem
696 	 */
697 	for (g = gr->gr_mem; *g; ++g) {
698 		if (strcmp(*g, user) == 0)
699 			return 1;	/* ok */
700 #ifdef SU_INDIRECT_GROUP
701 		++n;			/* count them */
702 #endif
703 	}
704 #ifdef SU_INDIRECT_GROUP
705 	/*
706 	 * No.
707 	 * Now we need to duplicate the gr_mem list, and recurse for
708 	 * each member to see if it is a group, and if so whether user is
709 	 * in it.
710 	 */
711 	gr_mem = malloc((n + 1) * sizeof (char *));
712 	for  (g = gr->gr_mem, i = 0; *g; ++g) {
713 		gr_mem[i] = strdup(*g);
714 		if (!gr_mem[i])
715 			err(1, "strdup");
716 		i++;
717 	}
718 	gr_mem[i++] = NULL;
719 
720 	for  (g = gr_mem; ok == 0 && *g; ++g) {
721 		/*
722 		 * If we get this far we don't accept empty/missing groups.
723 		 */
724 		ok = check_ingroup(-1, *g, user, 0);
725 	}
726 	for  (g = gr_mem; *g; ++g) {
727 		free(*g);
728 	}
729 	free(gr_mem);
730 #endif
731 	return ok;
732 }
733