xref: /illumos-gate/usr/src/cmd/su/su.c (revision 4763305e3243687c189d755d737d52205b2614ed)
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 (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright 2012 Milan Jurik. All rights reserved.
24  * Copyright 2014 Nexenta Systems, Inc.
25  * Copyright 2023 OmniOS Community Edition (OmniOSce) Association.
26  */
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 /*	  All Rights Reserved	*/
29 
30 /*	Copyright (c) 1987, 1988 Microsoft Corporation	*/
31 /*	  All Rights Reserved	*/
32 
33 /*
34  *	su [-] [name [arg ...]] change userid, `-' changes environment.
35  *	If SULOG is defined, all attempts to su to another user are
36  *	logged there.
37  *	If CONSOLE is defined, all successful attempts to su to uid 0
38  *	are also logged there.
39  *
40  *	If su cannot create, open, or write entries into SULOG,
41  *	(or on the CONSOLE, if defined), the entry will not
42  *	be logged -- thus losing a record of the su's attempted
43  *	during this period.
44  */
45 
46 #include <stdio.h>
47 #include <sys/types.h>
48 #include <sys/stat.h>
49 #include <sys/param.h>
50 #include <unistd.h>
51 #include <stdlib.h>
52 #include <crypt.h>
53 #include <pwd.h>
54 #include <shadow.h>
55 #include <time.h>
56 #include <signal.h>
57 #include <fcntl.h>
58 #include <string.h>
59 #include <locale.h>
60 #include <syslog.h>
61 #include <sys/utsname.h>
62 #include <sys/wait.h>
63 #include <grp.h>
64 #include <deflt.h>
65 #include <limits.h>
66 #include <errno.h>
67 #include <stdarg.h>
68 #include <user_attr.h>
69 #include <priv.h>
70 
71 #include <bsm/adt.h>
72 #include <bsm/adt_event.h>
73 
74 #include <security/pam_appl.h>
75 
76 #define	PATH	"/usr/bin:"		/* path for users other than root */
77 #define	SUPATH	"/usr/sbin:/usr/bin"	/* path for root */
78 #define	SUPRMT	"PS1=# "		/* primary prompt for root */
79 #define	ELIM 128
80 #define	ROOT 0
81 #ifdef	DYNAMIC_SU
82 #define	EMBEDDED_NAME	"embedded_su"
83 #define	DEF_ATTEMPTS	3		/* attempts to change password */
84 #endif	/* DYNAMIC_SU */
85 
86 #define	PW_FALSE	1		/* no password change */
87 #define	PW_TRUE		2		/* successful password change */
88 #define	PW_FAILED	3		/* failed password change */
89 
90 /*
91  * Intervals to sleep after failed su
92  */
93 #ifndef SLEEPTIME
94 #define	SLEEPTIME	4
95 #endif
96 
97 #define	DEFAULT_LOGIN "/etc/default/login"
98 #define	DEFFILE "/etc/default/su"
99 
100 
101 char	*Sulog, *Console;
102 char	*Path, *Supath;
103 
104 /*
105  * Locale variables to be propagated to "su -" environment
106  */
107 static char *initvar;
108 static char *initenv[] = {
109 	"TZ", "LANG", "LC_CTYPE",
110 	"LC_NUMERIC", "LC_TIME", "LC_COLLATE",
111 	"LC_MONETARY", "LC_MESSAGES", "LC_ALL", 0};
112 static char mail[30] = { "MAIL=/var/mail/" };
113 
114 static void envalt(void);
115 static void log(char *, char *, int);
116 static void to(int);
117 
118 enum messagemode { USAGE, ERR, WARN };
119 static void message(enum messagemode, char *, ...);
120 
121 static char *alloc_vsprintf(const char *, va_list);
122 static char *tail(char *);
123 
124 static void audit_success(int, struct passwd *, boolean_t);
125 static void audit_logout(adt_session_data_t *, au_event_t);
126 static void audit_failure(int, struct passwd *, char *, int, boolean_t);
127 
128 #ifdef DYNAMIC_SU
129 static void validate(char *, int *, boolean_t);
130 static int legalenvvar(char *);
131 static int su_conv(int, const struct pam_message **, struct pam_response **,
132     void *);
133 static int emb_su_conv(int, const struct pam_message **, struct pam_response **,
134     void *);
135 static void freeresponse(int, struct pam_response **response);
136 static struct pam_conv pam_conv = {su_conv, NULL};
137 static struct pam_conv emb_pam_conv = {emb_su_conv, NULL};
138 static void quotemsg(char *, ...);
139 static void readinitblock(void);
140 #else	/* !DYNAMIC_SU */
141 static void update_audit(struct passwd *pwd);
142 #endif	/* DYNAMIC_SU */
143 
144 static pam_handle_t	*pamh = NULL;	/* Authentication handle */
145 struct	passwd pwd;
146 char	pwdbuf[1024];			/* buffer for getpwnam_r() */
147 char	shell[] = "/usr/bin/sh";	/* default shell */
148 char	safe_shell[] = "/sbin/sh";	/* "fallback" shell */
149 char	su[PATH_MAX] = "su";		/* arg0 for exec of shprog */
150 char	homedir[PATH_MAX] = "HOME=";
151 char	logname[20] = "LOGNAME=";
152 char	*suprmt = SUPRMT;
153 char	termtyp[PATH_MAX] = "TERM=";
154 char	*term;
155 char	shelltyp[PATH_MAX] = "SHELL=";
156 char	*hz;
157 char	tznam[PATH_MAX];
158 char	hzname[10] = "HZ=";
159 char	path[PATH_MAX] = "PATH=";
160 char	supath[PATH_MAX] = "PATH=";
161 char	*envinit[ELIM];
162 extern	char **environ;
163 char *ttyn;
164 char *username;					/* the invoker */
165 static	int	dosyslog = 0;			/* use syslog? */
166 char	*myname;
167 #ifdef	DYNAMIC_SU
168 int pam_flags = 0;
169 boolean_t embedded = B_FALSE;
170 #endif	/* DYNAMIC_SU */
171 
172 int
173 main(int argc, char **argv)
174 {
175 #ifndef DYNAMIC_SU
176 	struct spwd sp;
177 	char  spbuf[1024];		/* buffer for getspnam_r() */
178 	char *password;
179 #endif	/* !DYNAMIC_SU */
180 	char *nptr;
181 	char *pshell;
182 	int eflag = 0;
183 	int envidx = 0;
184 	uid_t uid;
185 	gid_t gid;
186 	char *dir, *shprog, *name;
187 	char *ptr;
188 	char *prog = argv[0];
189 #ifdef DYNAMIC_SU
190 	int sleeptime = SLEEPTIME;
191 	char **pam_env = 0;
192 	int flags = 0;
193 	int retcode;
194 	int idx = 0;
195 	userattr_t *user_entry;
196 	char *authname;
197 #endif	/* DYNAMIC_SU */
198 	int pw_change = PW_FALSE;
199 	boolean_t isrole = B_FALSE;
200 
201 	(void) setlocale(LC_ALL, "");
202 #if !defined(TEXT_DOMAIN)	/* Should be defined by cc -D */
203 #define	TEXT_DOMAIN "SYS_TEST"	/* Use this only if it wasn't */
204 #endif
205 	(void) textdomain(TEXT_DOMAIN);
206 
207 	myname = tail(argv[0]);
208 
209 #ifdef	DYNAMIC_SU
210 	if (strcmp(myname, EMBEDDED_NAME) == 0) {
211 		embedded = B_TRUE;
212 		setbuf(stdin, NULL);
213 		setbuf(stdout, NULL);
214 		readinitblock();
215 	}
216 #endif	/* DYNAMIC_SU */
217 
218 	if (argc > 1 && *argv[1] == '-') {
219 		/* Explicitly check for just `-' (no trailing chars) */
220 		if (strlen(argv[1]) == 1) {
221 			eflag++;	/* set eflag if `-' is specified */
222 			argv++;
223 			argc--;
224 		} else {
225 			message(USAGE,
226 			    gettext("Usage: %s [-] [ username [ arg ... ] ]"),
227 			    prog);
228 			exit(1);
229 		}
230 	}
231 
232 	/*
233 	 * Determine specified userid, get their password file entry,
234 	 * and set variables to values in password file entry fields.
235 	 */
236 	if (argc > 1) {
237 		/*
238 		 * Usernames can't start with a `-', so we check for that to
239 		 * catch bad usage (like "su - -c ls").
240 		 */
241 		if (*argv[1] == '-') {
242 			message(USAGE,
243 			    gettext("Usage: %s [-] [ username [ arg ... ] ]"),
244 			    prog);
245 			exit(1);
246 		} else
247 			nptr = argv[1];	/* use valid command-line username */
248 	} else
249 		nptr = "root";		/* use default "root" username */
250 
251 	if (defopen(DEFFILE) == 0) {
252 
253 		if ((Sulog = defread("SULOG=")) != NULL)
254 			Sulog = strdup(Sulog);
255 		if ((Console = defread("CONSOLE=")) != NULL)
256 			Console = strdup(Console);
257 		if ((Path = defread("PATH=")) != NULL)
258 			Path = strdup(Path);
259 		if ((Supath = defread("SUPATH=")) != NULL)
260 			Supath = strdup(Supath);
261 		if ((ptr = defread("SYSLOG=")) != NULL)
262 			dosyslog = strcmp(ptr, "YES") == 0;
263 
264 		(void) defopen(NULL);
265 	}
266 	(void) strlcat(path, (Path) ? Path : PATH, sizeof (path));
267 	(void) strlcat(supath, (Supath) ? Supath : SUPATH, sizeof (supath));
268 
269 	if ((ttyn = ttyname(0)) == NULL)
270 		if ((ttyn = ttyname(1)) == NULL)
271 			if ((ttyn = ttyname(2)) == NULL)
272 				ttyn = "/dev/???";
273 	if ((username = cuserid(NULL)) == NULL)
274 		username = "(null)";
275 
276 	/*
277 	 * if Sulog defined, create SULOG, if it does not exist, with
278 	 * mode read/write user. Change owner and group to root
279 	 */
280 	if (Sulog != NULL) {
281 		(void) close(open(Sulog, O_WRONLY | O_APPEND | O_CREAT,
282 		    (S_IRUSR|S_IWUSR)));
283 		(void) chown(Sulog, (uid_t)ROOT, (gid_t)ROOT);
284 	}
285 
286 #ifdef DYNAMIC_SU
287 	authname = nptr;
288 
289 	if (((user_entry = getusernam(authname)) != NULL)) {
290 		kva_t *attr = user_entry->attr;
291 		char *kv;
292 
293 		if ((kv = kva_match(attr, USERATTR_TYPE_KW)) != NULL &&
294 		    ((strcmp(kv, USERATTR_TYPE_NONADMIN_KW) == 0) ||
295 		    (strcmp(kv, USERATTR_TYPE_ADMIN_KW) == 0))) {
296 			isrole = B_TRUE;
297 
298 			if ((kv = kva_match(attr,
299 			    USERATTR_ROLEAUTH_KW)) != NULL &&
300 			    strcmp(kv, USERATTR_ROLEAUTH_USER) == 0) {
301 				authname = cuserid(NULL);
302 			}
303 
304 		}
305 		free_userattr(user_entry);
306 	}
307 
308 	if (authname == NULL)
309 		exit(1);
310 
311 	if (pam_start(embedded ? EMBEDDED_NAME : "su", authname,
312 	    embedded ? &emb_pam_conv : &pam_conv, &pamh) != PAM_SUCCESS)
313 		exit(1);
314 	if (pam_set_item(pamh, PAM_TTY, ttyn) != PAM_SUCCESS)
315 		exit(1);
316 	if (getpwuid_r(getuid(), &pwd, pwdbuf, sizeof (pwdbuf)) == NULL ||
317 	    pam_set_item(pamh, PAM_AUSER, pwd.pw_name) != PAM_SUCCESS)
318 		exit(1);
319 #endif	/* DYNAMIC_SU */
320 
321 	openlog("su", LOG_CONS, LOG_AUTH);
322 
323 #ifdef DYNAMIC_SU
324 
325 	/*
326 	 * Use the same value of sleeptime and password required that
327 	 * login(1) uses.
328 	 * This is obtained by reading the file /etc/default/login
329 	 * using the def*() functions
330 	 */
331 	if (defopen(DEFAULT_LOGIN) == 0) {
332 		if ((ptr = defread("SLEEPTIME=")) != NULL) {
333 			sleeptime = atoi(ptr);
334 			if (sleeptime < 0 || sleeptime > 5)
335 				sleeptime = SLEEPTIME;
336 		}
337 
338 		if ((ptr = defread("PASSREQ=")) != NULL &&
339 		    strcasecmp("YES", ptr) == 0)
340 			pam_flags |= PAM_DISALLOW_NULL_AUTHTOK;
341 
342 		(void) defopen((char *)NULL);
343 	}
344 	/*
345 	 * Ignore SIGQUIT and SIGINT
346 	 */
347 	(void) signal(SIGQUIT, SIG_IGN);
348 	(void) signal(SIGINT, SIG_IGN);
349 
350 	/* call pam_authenticate() to authenticate the user through PAM */
351 	if (getpwnam_r(nptr, &pwd, pwdbuf, sizeof (pwdbuf)) == NULL)
352 		retcode = PAM_USER_UNKNOWN;
353 	else if ((flags = (getuid() != (uid_t)ROOT)) != 0) {
354 		retcode = pam_authenticate(pamh, pam_flags);
355 	} else /* root user does not need to authenticate */
356 		retcode = PAM_SUCCESS;
357 
358 	if (retcode != PAM_SUCCESS) {
359 		/*
360 		 * 1st step: audit and log the error.
361 		 * 2nd step: sleep.
362 		 * 3rd step: print out message to user.
363 		 */
364 		/* don't let audit_failure distinguish a role here */
365 		audit_failure(PW_FALSE, NULL, nptr, retcode, B_FALSE);
366 		switch (retcode) {
367 		case PAM_USER_UNKNOWN:
368 			closelog();
369 			(void) sleep(sleeptime);
370 			message(ERR, gettext("Unknown id: %s"), nptr);
371 			break;
372 
373 		case PAM_AUTH_ERR:
374 			if (Sulog != NULL)
375 				log(Sulog, nptr, 0);	/* log entry */
376 			if (dosyslog)
377 				syslog(LOG_CRIT, "'su %s' failed for %s on %s",
378 				    pwd.pw_name, username, ttyn);
379 			closelog();
380 			(void) sleep(sleeptime);
381 			message(ERR, gettext("Sorry"));
382 			break;
383 
384 		case PAM_CONV_ERR:
385 		default:
386 			if (dosyslog)
387 				syslog(LOG_CRIT, "'su %s' failed for %s on %s",
388 				    pwd.pw_name, username, ttyn);
389 			closelog();
390 			(void) sleep(sleeptime);
391 			message(ERR, gettext("Sorry"));
392 			break;
393 		}
394 
395 		(void) signal(SIGQUIT, SIG_DFL);
396 		(void) signal(SIGINT, SIG_DFL);
397 		exit(1);
398 	}
399 	if (flags)
400 		validate(username, &pw_change, isrole);
401 	if (pam_setcred(pamh, PAM_REINITIALIZE_CRED) != PAM_SUCCESS) {
402 		message(ERR, gettext("unable to set credentials"));
403 		exit(2);
404 	}
405 	if (dosyslog)
406 		syslog(pwd.pw_uid == 0 ? LOG_NOTICE : LOG_INFO,
407 		    "'su %s' succeeded for %s on %s",
408 		    pwd.pw_name, username, ttyn);
409 	closelog();
410 	(void) signal(SIGQUIT, SIG_DFL);
411 	(void) signal(SIGINT, SIG_DFL);
412 #else	/* !DYNAMIC_SU */
413 	if ((getpwnam_r(nptr, &pwd, pwdbuf, sizeof (pwdbuf)) == NULL) ||
414 	    (getspnam_r(nptr, &sp, spbuf, sizeof (spbuf)) == NULL)) {
415 		message(ERR, gettext("Unknown id: %s"), nptr);
416 		audit_failure(PW_FALSE, NULL, nptr, PAM_USER_UNKNOWN, B_FALSE);
417 		closelog();
418 		exit(1);
419 	}
420 
421 	/*
422 	 * Prompt for password if invoking user is not root or
423 	 * if specified(new) user requires a password
424 	 */
425 	if (sp.sp_pwdp[0] == '\0' || getuid() == (uid_t)ROOT)
426 		goto ok;
427 	password = getpass(gettext("Password:"));
428 
429 	if ((strcmp(sp.sp_pwdp, crypt(password, sp.sp_pwdp)) != 0)) {
430 		/* clear password file entry */
431 		(void) memset((void *)spbuf, 0, sizeof (spbuf));
432 		if (Sulog != NULL)
433 			log(Sulog, nptr, 0);    /* log entry */
434 		message(ERR, gettext("Sorry"));
435 		audit_failure(PW_FALSE, NULL, nptr, PAM_AUTH_ERR, B_FALSE);
436 		if (dosyslog)
437 			syslog(LOG_CRIT, "'su %s' failed for %s on %s",
438 			    pwd.pw_name, username, ttyn);
439 		closelog();
440 		exit(2);
441 	}
442 	/* clear password file entry */
443 	(void) memset((void *)spbuf, 0, sizeof (spbuf));
444 ok:
445 	/* update audit session in a non-pam environment */
446 	update_audit(&pwd);
447 	if (dosyslog)
448 		syslog(pwd.pw_uid == 0 ? LOG_NOTICE : LOG_INFO,
449 		    "'su %s' succeeded for %s on %s",
450 		    pwd.pw_name, username, ttyn);
451 #endif	/* DYNAMIC_SU */
452 
453 	audit_success(pw_change, &pwd, isrole);
454 	uid = pwd.pw_uid;
455 	gid = pwd.pw_gid;
456 	dir = strdup(pwd.pw_dir);
457 	shprog = strdup(pwd.pw_shell);
458 	name = strdup(pwd.pw_name);
459 
460 	if (Sulog != NULL)
461 		log(Sulog, nptr, 1);	/* log entry */
462 
463 	/* set user and group ids to specified user */
464 
465 	/* set the real (and effective) GID */
466 	if (setgid(gid) == -1) {
467 		message(ERR, gettext("Invalid GID"));
468 		exit(2);
469 	}
470 	/* Initialize the supplementary group access list. */
471 	if (!nptr)
472 		exit(2);
473 	if (initgroups(nptr, gid) == -1) {
474 		exit(2);
475 	}
476 	/* set the real (and effective) UID */
477 	if (setuid(uid) == -1) {
478 		message(ERR, gettext("Invalid UID"));
479 		exit(2);
480 	}
481 
482 	/*
483 	 * If new user's shell field is neither NULL nor equal to /usr/bin/sh,
484 	 * set:
485 	 *
486 	 *	pshell = their shell
487 	 *	su = [-]last component of shell's pathname
488 	 *
489 	 * Otherwise, set the shell to /usr/bin/sh and set argv[0] to '[-]su'.
490 	 */
491 	if (shprog[0] != '\0' && strcmp(shell, shprog) != 0) {
492 		char *p;
493 
494 		pshell = shprog;
495 		(void) strcpy(su, eflag ? "-" : "");
496 
497 		if ((p = strrchr(pshell, '/')) != NULL)
498 			(void) strlcat(su, p + 1, sizeof (su));
499 		else
500 			(void) strlcat(su, pshell, sizeof (su));
501 	} else {
502 		pshell = shell;
503 		(void) strcpy(su, eflag ? "-su" : "su");
504 	}
505 
506 	/*
507 	 * set environment variables for new user;
508 	 * arg0 for exec of shprog must now contain `-'
509 	 * so that environment of new user is given
510 	 */
511 	if (eflag) {
512 		int j;
513 		char *var;
514 
515 		if (strlen(dir) == 0) {
516 			(void) strcpy(dir, "/");
517 			message(WARN, gettext("No directory! Using home=/"));
518 		}
519 		(void) strlcat(homedir, dir, sizeof (homedir));
520 		(void) strlcat(logname, name, sizeof (logname));
521 		if ((hz = getenv("HZ")) != NULL)
522 			(void) strlcat(hzname, hz, sizeof (hzname));
523 
524 		(void) strlcat(shelltyp, pshell, sizeof (shelltyp));
525 
526 		if (chdir(dir) < 0) {
527 			message(ERR, gettext("No directory!"));
528 			exit(1);
529 		}
530 		envinit[envidx = 0] = homedir;
531 		envinit[++envidx] = ((uid == (uid_t)ROOT) ? supath : path);
532 		envinit[++envidx] = logname;
533 		envinit[++envidx] = hzname;
534 		if ((term = getenv("TERM")) != NULL) {
535 			(void) strlcat(termtyp, term, sizeof (termtyp));
536 			envinit[++envidx] = termtyp;
537 		}
538 		envinit[++envidx] = shelltyp;
539 
540 		(void) strlcat(mail, name, sizeof (mail));
541 		envinit[++envidx] = mail;
542 
543 		/*
544 		 * Fetch the relevant locale/TZ environment variables from
545 		 * the inherited environment.
546 		 *
547 		 * We have a priority here for setting TZ. If TZ is set in
548 		 * in the inherited environment, that value remains top
549 		 * priority. If the file /etc/default/login has TIMEZONE set,
550 		 * that has second highest priority.
551 		 */
552 		tznam[0] = '\0';
553 		for (j = 0; initenv[j] != 0; j++) {
554 			if ((initvar = getenv(initenv[j])) != NULL) {
555 
556 				/*
557 				 * Skip over values beginning with '/' for
558 				 * security.
559 				 */
560 				if (initvar[0] == '/')  continue;
561 
562 				if (strcmp(initenv[j], "TZ") == 0) {
563 					(void) strcpy(tznam, "TZ=");
564 					(void) strlcat(tznam, initvar,
565 					    sizeof (tznam));
566 
567 				} else {
568 					var = (char *)
569 					    malloc(strlen(initenv[j])
570 					    + strlen(initvar)
571 					    + 2);
572 					if (var == NULL) {
573 						perror("malloc");
574 						exit(4);
575 					}
576 					(void) strcpy(var, initenv[j]);
577 					(void) strcat(var, "=");
578 					(void) strcat(var, initvar);
579 					envinit[++envidx] = var;
580 				}
581 			}
582 		}
583 
584 		/*
585 		 * Check if TZ was found. If not then try to read it from
586 		 * /etc/default/login.
587 		 */
588 		if (tznam[0] == '\0') {
589 			if (defopen(DEFAULT_LOGIN) == 0) {
590 				if ((initvar = defread("TIMEZONE=")) != NULL) {
591 					(void) strcpy(tznam, "TZ=");
592 					(void) strlcat(tznam, initvar,
593 					    sizeof (tznam));
594 				}
595 				(void) defopen(NULL);
596 			}
597 		}
598 
599 		if (tznam[0] != '\0')
600 			envinit[++envidx] = tznam;
601 
602 #ifdef DYNAMIC_SU
603 		/*
604 		 * set the PAM environment variables -
605 		 * check for legal environment variables
606 		 */
607 		if ((pam_env = pam_getenvlist(pamh)) != 0) {
608 			while (pam_env[idx] != 0) {
609 				if (envidx + 2 < ELIM &&
610 				    legalenvvar(pam_env[idx])) {
611 					envinit[++envidx] = pam_env[idx];
612 				}
613 				idx++;
614 			}
615 		}
616 #endif	/* DYNAMIC_SU */
617 		envinit[++envidx] = NULL;
618 		environ = envinit;
619 	} else {
620 		char **pp = environ, **qq, *p;
621 
622 		while ((p = *pp) != NULL) {
623 			if (*p == 'L' && p[1] == 'D' && p[2] == '_') {
624 				for (qq = pp; (*qq = qq[1]) != NULL; qq++)
625 					;
626 				/* pp is not advanced */
627 			} else {
628 				pp++;
629 			}
630 		}
631 	}
632 
633 #ifdef DYNAMIC_SU
634 	if (pamh)
635 		(void) pam_end(pamh, PAM_SUCCESS);
636 #endif	/* DYNAMIC_SU */
637 
638 	/*
639 	 * if new user is root:
640 	 *	if CONSOLE defined, log entry there;
641 	 *	if eflag not set, change environment to that of root.
642 	 */
643 	if (uid == (uid_t)ROOT) {
644 		if (Console != NULL)
645 			if (strcmp(ttyn, Console) != 0) {
646 				(void) signal(SIGALRM, to);
647 				(void) alarm(30);
648 				log(Console, nptr, 1);
649 				(void) alarm(0);
650 			}
651 		if (!eflag)
652 			envalt();
653 	}
654 
655 	/*
656 	 * Default for SIGCPU and SIGXFSZ.  Shells inherit
657 	 * signal disposition from parent.  And the
658 	 * shells should have default dispositions for these
659 	 * signals.
660 	 */
661 	(void) signal(SIGXCPU, SIG_DFL);
662 	(void) signal(SIGXFSZ, SIG_DFL);
663 
664 #ifdef	DYNAMIC_SU
665 	if (embedded) {
666 		(void) puts("SUCCESS");
667 		/*
668 		 * After this point, we're no longer talking the
669 		 * embedded_su protocol, so turn it off.
670 		 */
671 		embedded = B_FALSE;
672 	}
673 #endif	/* DYNAMIC_SU */
674 
675 	/*
676 	 * if additional arguments, exec shell program with array
677 	 * of pointers to arguments:
678 	 *	-> if shell = default, then su = [-]su
679 	 *	-> if shell != default, then su = [-]last component of
680 	 *						shell's pathname
681 	 *
682 	 * if no additional arguments, exec shell with arg0 of su
683 	 * where:
684 	 *	-> if shell = default, then su = [-]su
685 	 *	-> if shell != default, then su = [-]last component of
686 	 *						shell's pathname
687 	 */
688 	if (argc > 2) {
689 		argv[1] = su;
690 		(void) execv(pshell, &argv[1]);
691 	} else
692 		(void) execl(pshell, su, 0);
693 
694 
695 	/*
696 	 * Try to clean up after an administrator who has made a mistake
697 	 * configuring root's shell; if root's shell is other than /sbin/sh,
698 	 * try exec'ing /sbin/sh instead.
699 	 */
700 	if ((uid == (uid_t)ROOT) && (strcmp(name, "root") == 0) &&
701 	    (strcmp(safe_shell, pshell) != 0)) {
702 		message(WARN,
703 		    gettext("No shell %s.  Trying fallback shell %s."),
704 		    pshell, safe_shell);
705 
706 		if (eflag) {
707 			(void) strcpy(su, "-sh");
708 			(void) strlcpy(shelltyp + strlen("SHELL="),
709 			    safe_shell, sizeof (shelltyp) - strlen("SHELL="));
710 		} else {
711 			(void) strcpy(su, "sh");
712 		}
713 
714 		if (argc > 2) {
715 			argv[1] = su;
716 			(void) execv(safe_shell, &argv[1]);
717 		} else {
718 			(void) execl(safe_shell, su, 0);
719 		}
720 		message(ERR, gettext("Couldn't exec fallback shell %s: %s"),
721 		    safe_shell, strerror(errno));
722 	} else {
723 		message(ERR, gettext("No shell"));
724 	}
725 	return (3);
726 }
727 
728 /*
729  * Environment altering routine -
730  *	This routine is called when a user is su'ing to root
731  *	without specifying the - flag.
732  *	The user's PATH and PS1 variables are reset
733  *	to the correct value for root.
734  *	All of the user's other environment variables retain
735  *	their current values after the su (if they are exported).
736  */
737 static void
738 envalt(void)
739 {
740 	/*
741 	 * If user has PATH variable in their environment, change its value
742 	 *		to /bin:/etc:/usr/bin ;
743 	 * if user does not have PATH variable, add it to the user's
744 	 *		environment;
745 	 * if either of the above fail, an error message is printed.
746 	 */
747 	if (putenv(supath) != 0) {
748 		message(ERR,
749 		    gettext("unable to obtain memory to expand environment"));
750 		exit(4);
751 	}
752 
753 	/*
754 	 * If user has PROMPT variable in their environment, change its value
755 	 *		to # ;
756 	 * if user does not have PROMPT variable, add it to the user's
757 	 *		environment;
758 	 * if either of the above fail, an error message is printed.
759 	 */
760 	if (putenv(suprmt) != 0) {
761 		message(ERR,
762 		    gettext("unable to obtain memory to expand environment"));
763 		exit(4);
764 	}
765 }
766 
767 /*
768  * Logging routine -
769  *	where = SULOG or CONSOLE
770  *	towho = specified user ( user being su'ed to )
771  *	how = 0 if su attempt failed; 1 if su attempt succeeded
772  */
773 static void
774 log(char *where, char *towho, int how)
775 {
776 	FILE *logf;
777 	time_t now;
778 	struct tm *tmp;
779 
780 	/*
781 	 * open SULOG or CONSOLE - if open fails, return
782 	 */
783 	if ((logf = fopen(where, "a")) == NULL)
784 		return;
785 
786 	now = time(0);
787 	tmp = localtime(&now);
788 
789 	/*
790 	 * write entry into SULOG or onto CONSOLE - if write fails, return
791 	 */
792 	(void) fprintf(logf, "SU %.2d/%.2d %.2d:%.2d %c %s %s-%s\n",
793 	    tmp->tm_mon + 1, tmp->tm_mday, tmp->tm_hour, tmp->tm_min,
794 	    how ? '+' : '-', ttyn + sizeof ("/dev/") - 1, username, towho);
795 
796 	(void) fclose(logf);	/* close SULOG or CONSOLE */
797 }
798 
799 /*ARGSUSED*/
800 static void
801 to(int sig)
802 {}
803 
804 /*
805  * audit_success - audit successful su
806  *
807  *	Entry	process audit context established -- i.e., pam_setcred()
808  *			or equivalent called.
809  *		pw_change = PW_TRUE, if successful password change audit
810  *				required.
811  *		pwd = passwd entry for new user.
812  */
813 
814 static void
815 audit_success(int pw_change, struct passwd *pwd, boolean_t isrole)
816 {
817 	adt_session_data_t	*ah = NULL;
818 	adt_event_data_t	*event;
819 	au_event_t		event_id = ADT_su;
820 
821 	if (adt_start_session(&ah, NULL, ADT_USE_PROC_DATA) != 0) {
822 		syslog(LOG_AUTH | LOG_ALERT,
823 		    "adt_start_session(ADT_su): %m");
824 		return;
825 	}
826 	if (isrole)
827 		event_id = ADT_role_login;
828 
829 	/* since proc uid/gid not yet updated */
830 	if (adt_set_user(ah, pwd->pw_uid, pwd->pw_gid, pwd->pw_uid,
831 	    pwd->pw_gid, NULL, ADT_USER) != 0) {
832 		syslog(LOG_AUTH | LOG_ERR,
833 		    "adt_set_user(ADT_su, ADT_FAILURE): %m");
834 	}
835 	if ((event = adt_alloc_event(ah, event_id)) == NULL) {
836 		syslog(LOG_AUTH | LOG_ALERT, "adt_alloc_event(ADT_su): %m");
837 	} else if (adt_put_event(event, ADT_SUCCESS, ADT_SUCCESS) != 0) {
838 		syslog(LOG_AUTH | LOG_ALERT,
839 		    "adt_put_event(ADT_su, ADT_SUCCESS): %m");
840 	}
841 
842 	if (pw_change == PW_TRUE) {
843 		/* Also audit password change */
844 		adt_free_event(event);
845 		if ((event = adt_alloc_event(ah, ADT_passwd)) == NULL) {
846 			syslog(LOG_AUTH | LOG_ALERT,
847 			    "adt_alloc_event(ADT_passwd): %m");
848 		} else if (adt_put_event(event, ADT_SUCCESS,
849 		    ADT_SUCCESS) != 0) {
850 			syslog(LOG_AUTH | LOG_ALERT,
851 			    "adt_put_event(ADT_passwd, ADT_SUCCESS): %m");
852 		}
853 	}
854 	adt_free_event(event);
855 	/*
856 	 * The preceeding code is a noop if audit isn't enabled,
857 	 * but, let's not make a new process when it's not necessary.
858 	 */
859 	if (adt_audit_state(AUC_AUDITING)) {
860 		audit_logout(ah, event_id);	/* fork to catch logout */
861 	}
862 	(void) adt_end_session(ah);
863 }
864 
865 
866 /*
867  * audit_logout - audit successful su logout
868  *
869  *	Entry	ah = Successful su audit handle
870  *		event_id = su event ID: ADT_su, ADT_role_login
871  *
872  *	Exit	Errors are just ignored and we go on.
873  *		su logout event written.
874  */
875 static void
876 audit_logout(adt_session_data_t *ah, au_event_t event_id)
877 {
878 	adt_event_data_t	*event;
879 	int			status;		/* wait status */
880 	pid_t			pid;
881 	priv_set_t		*priv;		/* waiting process privs */
882 
883 	if (event_id == ADT_su) {
884 		event_id = ADT_su_logout;
885 	} else {
886 		event_id = ADT_role_logout;
887 	}
888 	if ((event = adt_alloc_event(ah, event_id)) == NULL) {
889 		syslog(LOG_AUTH | LOG_ALERT,
890 		    "adt_alloc_event(ADT_su_logout): %m");
891 		return;
892 	}
893 	if ((priv = priv_allocset())  == NULL) {
894 		syslog(LOG_AUTH | LOG_ALERT,
895 		    "su audit_logout: could not alloc basic privs: %m");
896 		adt_free_event(event);
897 		return;
898 	}
899 
900 	/*
901 	 * The child returns and continues su processing.
902 	 * The parent's sole job is to wait for child exit, write the
903 	 * logout audit record, and replay the child's exit code.
904 	 */
905 	if ((pid = fork()) == 0) {
906 		/* child */
907 
908 		adt_free_event(event);
909 		priv_freeset(priv);
910 		return;
911 	}
912 	if (pid == -1) {
913 		/* failure */
914 
915 		syslog(LOG_AUTH | LOG_ALERT,
916 		    "su audit_logout: could not fork: %m");
917 		adt_free_event(event);
918 		priv_freeset(priv);
919 		return;
920 	}
921 
922 	/* parent process */
923 
924 	/*
925 	 * When this routine is called, the current working
926 	 * directory is the unknown and there are unknown open
927 	 * files. For the waiting process, change the current
928 	 * directory to root and close open files so that
929 	 * directories can be unmounted if necessary.
930 	 */
931 	if (chdir("/") != 0) {
932 		syslog(LOG_AUTH | LOG_ALERT,
933 		    "su audit_logout: could not chdir /: %m");
934 	}
935 	/*
936 	 * Reduce privileges to just those needed.
937 	 */
938 	priv_basicset(priv);
939 	(void) priv_delset(priv, PRIV_PROC_EXEC);
940 	(void) priv_delset(priv, PRIV_PROC_FORK);
941 	(void) priv_delset(priv, PRIV_PROC_INFO);
942 	(void) priv_delset(priv, PRIV_PROC_SESSION);
943 	(void) priv_delset(priv, PRIV_FILE_LINK_ANY);
944 	if ((priv_addset(priv, PRIV_PROC_AUDIT) != 0) ||
945 	    (setppriv(PRIV_SET, PRIV_PERMITTED, priv) != 0)) {
946 		syslog(LOG_AUTH | LOG_ALERT,
947 		    "su audit_logout: could not reduce privs: %m");
948 	}
949 	closefrom(0);
950 	priv_freeset(priv);
951 
952 	for (;;) {
953 		if (pid != waitpid(pid, &status, WUNTRACED)) {
954 			if (errno == ECHILD) {
955 				/*
956 				 * No existing child with the given pid. Lets
957 				 * audit the logout.
958 				 */
959 				break;
960 			}
961 			continue;
962 		}
963 
964 		if (WIFEXITED(status) || WIFSIGNALED(status)) {
965 			/*
966 			 * The child shell exited or was terminated by
967 			 * a signal. Lets audit logout.
968 			 */
969 			break;
970 		} else if (WIFSTOPPED(status)) {
971 			pid_t pgid;
972 			int fd;
973 			void (*sg_handler)();
974 			/*
975 			 * The child shell has been stopped/suspended.
976 			 * We need to suspend here as well and pass down
977 			 * the control to the parent process.
978 			 */
979 			sg_handler = signal(WSTOPSIG(status), SIG_DFL);
980 			(void) sigsend(P_PGID, getpgrp(), WSTOPSIG(status));
981 			/*
982 			 * We stop here. When resumed, mark the child
983 			 * shell group as foreground process group
984 			 * which gives the child shell a control over
985 			 * the controlling terminal.
986 			 */
987 			(void) signal(WSTOPSIG(status), sg_handler);
988 
989 			pgid = getpgid(pid);
990 			if ((fd = open("/dev/tty", O_RDWR)) != -1) {
991 				/*
992 				 * Pass down the control over the controlling
993 				 * terminal iff we are in a foreground process
994 				 * group. Otherwise, we are in a background
995 				 * process group and the kernel will send
996 				 * SIGTTOU signal to stop us (by default).
997 				 */
998 				if (tcgetpgrp(fd) == getpgrp()) {
999 					(void) tcsetpgrp(fd, pgid);
1000 				}
1001 				(void) close(fd);
1002 			}
1003 			/* Wake up the child shell */
1004 			(void) sigsend(P_PGID, pgid, SIGCONT);
1005 		}
1006 	}
1007 
1008 	(void) adt_put_event(event, ADT_SUCCESS, ADT_SUCCESS);
1009 	adt_free_event(event);
1010 	(void) adt_end_session(ah);
1011 	exit(WEXITSTATUS(status));
1012 }
1013 
1014 
1015 /*
1016  * audit_failure - audit failed su
1017  *
1018  *	Entry	New audit context not set.
1019  *		pw_change == PW_FALSE, if no password change requested.
1020  *			     PW_FAILED, if failed password change audit
1021  *				      required.
1022  *		pwd = NULL, or password entry to use.
1023  *		user = username entered.  Add to record if pwd == NULL.
1024  *		pamerr = PAM error code; reason for failure.
1025  */
1026 
1027 static void
1028 audit_failure(int pw_change, struct passwd *pwd, char *user, int pamerr,
1029     boolean_t isrole)
1030 {
1031 	adt_session_data_t	*ah;	/* audit session handle */
1032 	adt_event_data_t	*event;	/* event to generate */
1033 	au_event_t		event_id = ADT_su;
1034 
1035 	if (adt_start_session(&ah, NULL, ADT_USE_PROC_DATA) != 0) {
1036 		syslog(LOG_AUTH | LOG_ALERT,
1037 		    "adt_start_session(ADT_su, ADT_FAILURE): %m");
1038 		return;
1039 	}
1040 
1041 	if (pwd != NULL) {
1042 		/* target user authenticated, merge audit state */
1043 		if (adt_set_user(ah, pwd->pw_uid, pwd->pw_gid, pwd->pw_uid,
1044 		    pwd->pw_gid, NULL, ADT_UPDATE) != 0) {
1045 			syslog(LOG_AUTH | LOG_ERR,
1046 			    "adt_set_user(ADT_su, ADT_FAILURE): %m");
1047 		}
1048 		if (isrole)
1049 			event_id = ADT_role_login;
1050 	}
1051 	if ((event = adt_alloc_event(ah, event_id)) == NULL) {
1052 		syslog(LOG_AUTH | LOG_ALERT,
1053 		    "adt_alloc_event(ADT_su, ADT_FAILURE): %m");
1054 		return;
1055 	}
1056 	/*
1057 	 * can't tell if user not found is a role, so always use su
1058 	 * If we do pass in pwd when the JNI is fixed, then can
1059 	 * distinguish and set name in both su and role_login
1060 	 */
1061 	if (pwd == NULL) {
1062 		/*
1063 		 * this should be "fail_user" rather than "message"
1064 		 * see adt_xml.  The JNI breaks, so for now we leave
1065 		 * this alone.
1066 		 */
1067 		event->adt_su.message = user;
1068 	}
1069 	if (adt_put_event(event, ADT_FAILURE,
1070 	    ADT_FAIL_PAM + pamerr) != 0) {
1071 		syslog(LOG_AUTH | LOG_ALERT,
1072 		    "adt_put_event(ADT_su(ADT_FAIL, %s): %m",
1073 		    pam_strerror(pamh, pamerr));
1074 	}
1075 	if (pw_change != PW_FALSE) {
1076 		/* Also audit password change failed */
1077 		adt_free_event(event);
1078 		if ((event = adt_alloc_event(ah, ADT_passwd)) == NULL) {
1079 			syslog(LOG_AUTH | LOG_ALERT,
1080 			    "su: adt_alloc_event(ADT_passwd): %m");
1081 		} else if (adt_put_event(event, ADT_FAILURE,
1082 		    ADT_FAIL_PAM + pamerr) != 0) {
1083 			syslog(LOG_AUTH | LOG_ALERT,
1084 			    "su: adt_put_event(ADT_passwd, ADT_FAILURE): %m");
1085 		}
1086 	}
1087 	adt_free_event(event);
1088 	(void) adt_end_session(ah);
1089 }
1090 
1091 #ifdef DYNAMIC_SU
1092 /*
1093  * su_conv():
1094  *	This is the conv (conversation) function called from
1095  *	a PAM authentication module to print error messages
1096  *	or garner information from the user.
1097  */
1098 static int
1099 su_conv(int num_msg, const struct pam_message **msg,
1100     struct pam_response **response, void *appdata_ptr)
1101 {
1102 	const struct pam_message *m;
1103 	struct pam_response *r;
1104 	char *temp;
1105 	int k;
1106 	char respbuf[PAM_MAX_RESP_SIZE];
1107 
1108 	if (num_msg <= 0)
1109 		return (PAM_CONV_ERR);
1110 
1111 	*response = (struct pam_response *)calloc(num_msg,
1112 	    sizeof (struct pam_response));
1113 	if (*response == NULL)
1114 		return (PAM_BUF_ERR);
1115 
1116 	k = num_msg;
1117 	m = *msg;
1118 	r = *response;
1119 	while (k--) {
1120 
1121 		switch (m->msg_style) {
1122 
1123 		case PAM_PROMPT_ECHO_OFF:
1124 			errno = 0;
1125 			temp = getpassphrase(m->msg);
1126 			if (errno == EINTR)
1127 				return (PAM_CONV_ERR);
1128 			if (temp != NULL) {
1129 				r->resp = strdup(temp);
1130 				if (r->resp == NULL) {
1131 					freeresponse(num_msg, response);
1132 					return (PAM_BUF_ERR);
1133 				}
1134 			}
1135 			break;
1136 
1137 		case PAM_PROMPT_ECHO_ON:
1138 			if (m->msg != NULL) {
1139 				(void) fputs(m->msg, stdout);
1140 			}
1141 
1142 			(void) fgets(respbuf, sizeof (respbuf), stdin);
1143 			temp = strchr(respbuf, '\n');
1144 			if (temp != NULL)
1145 				*temp = '\0';
1146 
1147 			r->resp = strdup(respbuf);
1148 			if (r->resp == NULL) {
1149 				freeresponse(num_msg, response);
1150 				return (PAM_BUF_ERR);
1151 			}
1152 			break;
1153 
1154 		case PAM_ERROR_MSG:
1155 			if (m->msg != NULL) {
1156 				(void) fputs(m->msg, stderr);
1157 				(void) fputs("\n", stderr);
1158 			}
1159 			break;
1160 
1161 		case PAM_TEXT_INFO:
1162 			if (m->msg != NULL) {
1163 				(void) fputs(m->msg, stdout);
1164 				(void) fputs("\n", stdout);
1165 			}
1166 			break;
1167 
1168 		default:
1169 			break;
1170 		}
1171 		m++;
1172 		r++;
1173 	}
1174 	return (PAM_SUCCESS);
1175 }
1176 
1177 /*
1178  * emb_su_conv():
1179  *	This is the conv (conversation) function called from
1180  *	a PAM authentication module to print error messages
1181  *	or garner information from the user.
1182  *	This version is used for embedded_su.
1183  */
1184 static int
1185 emb_su_conv(int num_msg, const struct pam_message **msg,
1186     struct pam_response **response, void *appdata_ptr)
1187 {
1188 	const struct pam_message *m;
1189 	struct pam_response *r;
1190 	char *temp;
1191 	int k;
1192 	char respbuf[PAM_MAX_RESP_SIZE];
1193 
1194 	if (num_msg <= 0)
1195 		return (PAM_CONV_ERR);
1196 
1197 	*response = (struct pam_response *)calloc(num_msg,
1198 	    sizeof (struct pam_response));
1199 	if (*response == NULL)
1200 		return (PAM_BUF_ERR);
1201 
1202 	/* First, send the prompts */
1203 	(void) printf("CONV %d\n", num_msg);
1204 	k = num_msg;
1205 	m = *msg;
1206 	while (k--) {
1207 		switch (m->msg_style) {
1208 
1209 		case PAM_PROMPT_ECHO_OFF:
1210 			(void) puts("PAM_PROMPT_ECHO_OFF");
1211 			goto msg_common;
1212 
1213 		case PAM_PROMPT_ECHO_ON:
1214 			(void) puts("PAM_PROMPT_ECHO_ON");
1215 			goto msg_common;
1216 
1217 		case PAM_ERROR_MSG:
1218 			(void) puts("PAM_ERROR_MSG");
1219 			goto msg_common;
1220 
1221 		case PAM_TEXT_INFO:
1222 			(void) puts("PAM_TEXT_INFO");
1223 			/* fall through to msg_common */
1224 msg_common:
1225 			if (m->msg == NULL)
1226 				quotemsg(NULL);
1227 			else
1228 				quotemsg("%s", m->msg);
1229 			break;
1230 
1231 		default:
1232 			break;
1233 		}
1234 		m++;
1235 	}
1236 
1237 	/* Next, collect the responses */
1238 	k = num_msg;
1239 	m = *msg;
1240 	r = *response;
1241 	while (k--) {
1242 
1243 		switch (m->msg_style) {
1244 
1245 		case PAM_PROMPT_ECHO_OFF:
1246 		case PAM_PROMPT_ECHO_ON:
1247 			(void) fgets(respbuf, sizeof (respbuf), stdin);
1248 
1249 			temp = strchr(respbuf, '\n');
1250 			if (temp != NULL)
1251 				*temp = '\0';
1252 
1253 			r->resp = strdup(respbuf);
1254 			if (r->resp == NULL) {
1255 				freeresponse(num_msg, response);
1256 				return (PAM_BUF_ERR);
1257 			}
1258 
1259 			break;
1260 
1261 		case PAM_ERROR_MSG:
1262 		case PAM_TEXT_INFO:
1263 			break;
1264 
1265 		default:
1266 			break;
1267 		}
1268 		m++;
1269 		r++;
1270 	}
1271 	return (PAM_SUCCESS);
1272 }
1273 
1274 static void
1275 freeresponse(int num_msg, struct pam_response **response)
1276 {
1277 	struct pam_response *r;
1278 	int i;
1279 
1280 	/* free responses */
1281 	r = *response;
1282 	for (i = 0; i < num_msg; i++, r++) {
1283 		if (r->resp != NULL) {
1284 			/* Zap it in case it's a password */
1285 			(void) memset(r->resp, '\0', strlen(r->resp));
1286 			free(r->resp);
1287 		}
1288 	}
1289 	free(*response);
1290 	*response = NULL;
1291 }
1292 
1293 /*
1294  * Print a message, applying quoting for lines starting with '.'.
1295  *
1296  * I18n note:  \n is "safe" in all locales, and all locales use
1297  * a high-bit-set character to start multibyte sequences, so
1298  * scanning for a \n followed by a '.' is safe.
1299  */
1300 static void
1301 quotemsg(char *fmt, ...)
1302 {
1303 	if (fmt != NULL) {
1304 		char *msg;
1305 		char *p;
1306 		boolean_t bol;
1307 		va_list v;
1308 
1309 		va_start(v, fmt);
1310 		msg = alloc_vsprintf(fmt, v);
1311 		va_end(v);
1312 
1313 		bol = B_TRUE;
1314 		for (p = msg; *p != '\0'; p++) {
1315 			if (bol) {
1316 				if (*p == '.')
1317 					(void) putchar('.');
1318 				bol = B_FALSE;
1319 			}
1320 			(void) putchar(*p);
1321 			if (*p == '\n')
1322 				bol = B_TRUE;
1323 		}
1324 		(void) putchar('\n');
1325 		free(msg);
1326 	}
1327 	(void) putchar('.');
1328 	(void) putchar('\n');
1329 }
1330 
1331 /*
1332  * validate - Check that the account is valid for switching to.
1333  */
1334 static void
1335 validate(char *usernam, int *pw_change, boolean_t isrole)
1336 {
1337 	int error;
1338 	int tries;
1339 
1340 	if ((error = pam_acct_mgmt(pamh, pam_flags)) != PAM_SUCCESS) {
1341 		if (Sulog != NULL)
1342 			log(Sulog, pwd.pw_name, 0);    /* log entry */
1343 		if (error == PAM_NEW_AUTHTOK_REQD) {
1344 			tries = 0;
1345 			message(ERR, gettext("Password for user "
1346 			    "'%s' has expired"), pwd.pw_name);
1347 			while ((error = pam_chauthtok(pamh,
1348 			    PAM_CHANGE_EXPIRED_AUTHTOK)) != PAM_SUCCESS) {
1349 				if ((error == PAM_AUTHTOK_ERR ||
1350 				    error == PAM_TRY_AGAIN) &&
1351 				    (tries++ < DEF_ATTEMPTS)) {
1352 					continue;
1353 				}
1354 				message(ERR, gettext("Sorry"));
1355 				audit_failure(PW_FAILED, &pwd, NULL, error,
1356 				    isrole);
1357 				if (dosyslog)
1358 					syslog(LOG_CRIT,
1359 					    "'su %s' failed for %s on %s",
1360 					    pwd.pw_name, usernam, ttyn);
1361 				closelog();
1362 				exit(1);
1363 			}
1364 			*pw_change = PW_TRUE;
1365 			return;
1366 		} else {
1367 			message(ERR, gettext("Sorry"));
1368 			audit_failure(PW_FALSE, &pwd, NULL, error, isrole);
1369 			if (dosyslog)
1370 				syslog(LOG_CRIT, "'su %s' failed for %s on %s",
1371 				    pwd.pw_name, usernam, ttyn);
1372 			closelog();
1373 			exit(3);
1374 		}
1375 	}
1376 }
1377 
1378 static char *illegal[] = {
1379 	"SHELL=",
1380 	"HOME=",
1381 	"LOGNAME=",
1382 #ifndef NO_MAIL
1383 	"MAIL=",
1384 #endif
1385 	"CDPATH=",
1386 	"IFS=",
1387 	"PATH=",
1388 	"TZ=",
1389 	"HZ=",
1390 	"TERM=",
1391 	0
1392 };
1393 
1394 /*
1395  * legalenvvar - can PAM modules insert this environmental variable?
1396  */
1397 
1398 static int
1399 legalenvvar(char *s)
1400 {
1401 	register char **p;
1402 
1403 	for (p = illegal; *p; p++)
1404 		if (strncmp(s, *p, strlen(*p)) == 0)
1405 			return (0);
1406 
1407 	if (s[0] == 'L' && s[1] == 'D' && s[2] == '_')
1408 		return (0);
1409 
1410 	return (1);
1411 }
1412 
1413 /*
1414  * The embedded_su protocol allows the client application to supply
1415  * an initialization block terminated by a line with just a "." on it.
1416  *
1417  * This initialization block is currently unused, reserved for future
1418  * expansion.  Ignore it.  This is made very slightly more complex by
1419  * the desire to cleanly ignore input lines of any length, while still
1420  * correctly detecting a line with just a "." on it.
1421  *
1422  * I18n note:  It appears that none of the Solaris-supported locales
1423  * use 0x0a for any purpose other than newline, so looking for '\n'
1424  * seems safe.
1425  * All locales use high-bit-set leadin characters for their multi-byte
1426  * sequences, so a line consisting solely of ".\n" is what it appears
1427  * to be.
1428  */
1429 static void
1430 readinitblock(void)
1431 {
1432 	char buf[100];
1433 	boolean_t bol;
1434 
1435 	bol = B_TRUE;
1436 	for (;;) {
1437 		if (fgets(buf, sizeof (buf), stdin) == NULL)
1438 			return;
1439 		if (bol && strcmp(buf, ".\n") == 0)
1440 			return;
1441 		bol = (strchr(buf, '\n') != NULL);
1442 	}
1443 }
1444 #else	/* !DYNAMIC_SU */
1445 static void
1446 update_audit(struct passwd *pwd)
1447 {
1448 	adt_session_data_t	*ah;	/* audit session handle */
1449 
1450 	if (adt_start_session(&ah, NULL, ADT_USE_PROC_DATA) != 0) {
1451 		message(ERR, gettext("Sorry"));
1452 		if (dosyslog)
1453 			syslog(LOG_CRIT, "'su %s' failed for %s "
1454 			    "cannot start audit session %m",
1455 			    pwd->pw_name, username);
1456 		closelog();
1457 		exit(2);
1458 	}
1459 	if (adt_set_user(ah, pwd->pw_uid, pwd->pw_gid, pwd->pw_uid,
1460 	    pwd->pw_gid, NULL, ADT_UPDATE) != 0) {
1461 		if (dosyslog)
1462 			syslog(LOG_CRIT, "'su %s' failed for %s "
1463 			    "cannot update audit session %m",
1464 			    pwd->pw_name, username);
1465 		closelog();
1466 		exit(2);
1467 	}
1468 }
1469 #endif	/* DYNAMIC_SU */
1470 
1471 /*
1472  * Report an error, either a fatal one, a warning, or a usage message,
1473  * depending on the mode parameter.
1474  */
1475 /*ARGSUSED*/
1476 static void
1477 message(enum messagemode mode, char *fmt, ...)
1478 {
1479 	char *s;
1480 	va_list v;
1481 
1482 	va_start(v, fmt);
1483 	s = alloc_vsprintf(fmt, v);
1484 	va_end(v);
1485 
1486 #ifdef	DYNAMIC_SU
1487 	if (embedded) {
1488 		if (mode == WARN) {
1489 			(void) printf("CONV 1\n");
1490 			(void) printf("PAM_ERROR_MSG\n");
1491 		} else { /* ERR, USAGE */
1492 			(void) printf("ERROR\n");
1493 		}
1494 		if (mode == USAGE) {
1495 			quotemsg("%s", s);
1496 		} else { /* ERR, WARN */
1497 			quotemsg("%s: %s", myname, s);
1498 		}
1499 	} else {
1500 #endif	/* DYNAMIC_SU */
1501 		if (mode == USAGE) {
1502 			(void) fprintf(stderr, "%s\n", s);
1503 		} else { /* ERR, WARN */
1504 			(void) fprintf(stderr, "%s: %s\n", myname, s);
1505 		}
1506 #ifdef	DYNAMIC_SU
1507 	}
1508 #endif	/* DYNAMIC_SU */
1509 
1510 	free(s);
1511 }
1512 
1513 /*
1514  * Return a pointer to the last path component of a.
1515  */
1516 static char *
1517 tail(char *a)
1518 {
1519 	char *p;
1520 
1521 	p = strrchr(a, '/');
1522 	if (p == NULL)
1523 		p = a;
1524 	else
1525 		p++;	/* step over the '/' */
1526 
1527 	return (p);
1528 }
1529 
1530 static char *
1531 alloc_vsprintf(const char *fmt, va_list ap1)
1532 {
1533 	va_list ap2;
1534 	int n;
1535 	char buf[1];
1536 	char *s;
1537 
1538 	/*
1539 	 * We need to scan the argument list twice.  Save off a copy
1540 	 * of the argument list pointer(s) for the second pass.  Note that
1541 	 * we are responsible for va_end'ing our copy.
1542 	 */
1543 	va_copy(ap2, ap1);
1544 
1545 	/*
1546 	 * vsnprintf into a dummy to get a length.  One might
1547 	 * think that passing 0 as the length to snprintf would
1548 	 * do what we want, but it's defined not to.
1549 	 *
1550 	 * Perhaps we should sprintf into a 100 character buffer
1551 	 * or something like that, to avoid two calls to snprintf
1552 	 * in most cases.
1553 	 */
1554 	n = vsnprintf(buf, sizeof (buf), fmt, ap2);
1555 	va_end(ap2);
1556 
1557 	/*
1558 	 * Allocate an appropriately-sized buffer.
1559 	 */
1560 	s = malloc(n + 1);
1561 	if (s == NULL) {
1562 		perror("malloc");
1563 		exit(4);
1564 	}
1565 
1566 	(void) vsnprintf(s, n+1, fmt, ap1);
1567 
1568 	return (s);
1569 }
1570