2 * Copyright (c) 1988, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * @(#) Copyright (c) 1988, 1993, 1994 The Regents of the University of California. All rights reserved.
34 * @(#)su.c 8.3 (Berkeley) 4/2/94
35 * $FreeBSD: src/usr.bin/su/su.c,v 1.34.2.4 2002/06/16 21:04:15 nectar Exp $
36 * $DragonFly: src/usr.bin/su/su.c,v 1.7 2004/12/20 19:59:54 cpressey Exp $
39 #include <sys/cdefs.h>
40 #include <sys/param.h>
42 #include <sys/resource.h>
57 #include <login_cap.h>
67 static long get_su_principal(krb5_context context, const char *target_user,
68 const char *current_user, char **su_principal_name,
69 krb5_principal *su_principal);
70 static long kerberos5(krb5_context context, const char *current_user,
71 const char *target_user, krb5_principal su_principal,
74 int use_kerberos5 = 1;
78 #define LOGIN_CAP_ARG(x) x
80 #define LOGIN_CAP_ARG(x)
82 #if defined(KERBEROS5)
83 #define KERBEROS_ARG(x) x
85 #define KERBEROS_ARG(x)
87 #define COMMON_ARG(x) x
88 #define ARGSTR "-" COMMON_ARG("flm") LOGIN_CAP_ARG("c:") KERBEROS_ARG("K")
92 static void usage(void);
94 extern char **environ;
97 main(int argc, char **argv)
104 const char *p, *user, *shell = NULL;
105 const char **nargv, **np;
106 char **g, **cleanenv, *username, *entered_pass;
110 int asme, ch, asthem, fastlogin, prio, i;
111 enum { UNSET, YES, NO } iscsh = UNSET;
117 #if defined(KERBEROS5)
121 char *su_principal_name, *ccname;
122 krb5_context context;
123 krb5_principal su_principal;
125 char shellbuf[MAXPATHLEN];
130 asme = asthem = fastlogin = 0;
132 while((ch = getopt(argc, argv, ARGSTR)) != -1)
134 #if defined(KERBEROS5)
162 user = argv[optind++];
164 if (strlen(user) > MAXLOGNAME - 1) {
165 fprintf(stderr, "su: username too long.\n");
172 if ((nargv = malloc (sizeof (char *) * (argc + 4))) == NULL) {
173 errx(1, "malloc failure");
176 nargv[argc + 3] = NULL;
177 for (i = argc; i >= optind; i--)
178 nargv[i + 3] = argv[i];
183 #if defined(KERBEROS5)
184 k = auth_getval("auth_list");
185 if (k && !strstr(k, "kerberos")) {
188 su_principal_name = NULL;
190 if (krb5_init_context(&context) != 0)
194 prio = getpriority(PRIO_PROCESS, 0);
197 setpriority(PRIO_PROCESS, 0, -2);
198 openlog("su", LOG_CONS, 0);
200 /* get current login name and shell */
202 username = getlogin();
203 if (username == NULL || (pwd = getpwnam(username)) == NULL ||
205 pwd = getpwuid(ruid);
207 errx(1, "who are you?");
208 username = strdup(pwd->pw_name);
210 if (username == NULL)
213 if (pwd->pw_shell != NULL && *pwd->pw_shell != '\0') {
214 /* copy: pwd memory is recycled */
215 shell = strncpy(shellbuf, pwd->pw_shell, sizeof shellbuf);
216 shellbuf[sizeof shellbuf - 1] = '\0';
218 shell = _PATH_BSHELL;
223 /* get target login information, default to root */
224 if ((pwd = getpwnam(user)) == NULL) {
225 errx(1, "unknown login: %s", user);
229 lc = login_getpwclass(pwd);
232 errx(1, "only root may use -c");
233 lc = login_getclass(class);
235 errx(1, "unknown class: %s", class);
240 targetpass = strdup(pwd->pw_passwd);
246 if (get_su_principal(context, user, username,
247 &su_principal_name, &su_principal) != 0 ||
248 !krb5_kuserok(context, su_principal, user)) {
249 warnx("kerberos5: not in %s's ACL.", user);
255 * Only allow those with pw_gid==0 or those listed in
256 * group zero to su to root. If group zero entry is
257 * missing or empty, then allow anyone to su to root.
258 * iswheelsu will only be set if the user is EXPLICITLY
259 * listed in group zero.
261 if (pwd->pw_uid == 0 && (gr = getgrgid((gid_t)0)) &&
262 gr->gr_mem && *(gr->gr_mem)) {
263 for (g = gr->gr_mem;; ++g) {
269 "you are not in the correct group (%s) to su %s.",
273 if (strcmp(username, *g) == 0) {
281 /* if target requires a password, verify it */
282 if (*pwd->pw_passwd) {
286 pwd = getpwnam(username);
289 entered_pass = skey_getpass("Password:", pwd, 1);
290 if (!(!strcmp(pwd->pw_passwd, skey_crypt(entered_pass,
291 pwd->pw_passwd, pwd, 1))
293 || (iswheelsu && !strcmp(targetpass,
294 crypt(entered_pass, targetpass)))
298 entered_pass = getpass("Password:");
299 if (strcmp(pwd->pw_passwd, crypt(entered_pass,
303 if (use_kerberos5 && kerberos5(context,
304 username, user, su_principal,
308 fprintf(stderr, "Sorry\n");
309 syslog(LOG_AUTH|LOG_WARNING,
310 "BAD SU %s to %s%s", username, user,
314 #if defined(KERBEROS5)
320 pwd = getpwnam(user);
324 if (pwd->pw_expire && time(NULL) >= pwd->pw_expire) {
325 fprintf(stderr, "Sorry - account expired\n");
326 syslog(LOG_AUTH|LOG_WARNING,
327 "BAD SU %s to %s%s", username,
334 /* if asme and non-standard target shell, must be root */
335 if (!chshell(pwd->pw_shell) && ruid)
336 errx(1, "permission denied (shell).");
337 } else if (pwd->pw_shell && *pwd->pw_shell) {
338 shell = pwd->pw_shell;
341 shell = _PATH_BSHELL;
345 /* if we're forking a csh, we want to slightly muck the args */
346 if (iscsh == UNSET) {
347 p = strrchr(shell, '/');
352 if ((iscsh = strcmp(p, "csh") ? NO : YES) == NO)
353 iscsh = strcmp(p, "tcsh") ? NO : YES;
356 setpriority(PRIO_PROCESS, 0, prio);
359 /* Set everything now except the environment & umask */
360 setwhat = LOGIN_SETUSER|LOGIN_SETGROUP|LOGIN_SETRESOURCES|LOGIN_SETPRIORITY;
362 * Don't touch resource/priority settings if -m has been
363 * used or -l and -c hasn't, and we're not su'ing to root.
365 if ((asme || (!asthem && class == NULL)) && pwd->pw_uid)
366 setwhat &= ~(LOGIN_SETPRIORITY|LOGIN_SETRESOURCES);
367 if (setusercontext(lc, pwd, pwd->pw_uid, setwhat) < 0)
368 err(1, "setusercontext");
370 /* set permissions */
371 if (setgid(pwd->pw_gid) < 0)
373 if (initgroups(user, pwd->pw_gid))
374 errx(1, "initgroups failed");
375 if (setuid(pwd->pw_uid) < 0)
383 ccname = getenv("KRB5CCNAME");
385 if ((cleanenv = calloc(20, sizeof(char*))) == NULL)
390 /* set the su'd user's environment & umask */
391 setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETPATH|LOGIN_SETUMASK|LOGIN_SETENV);
393 setenv("PATH", _PATH_DEFPATH, 1);
396 setenv("TERM", p, 1);
399 setenv("KRB5CCNAME", ccname, 1);
401 if (chdir(pwd->pw_dir) < 0)
402 errx(1, "no directory");
404 if (asthem || pwd->pw_uid)
405 setenv("USER", pwd->pw_name, 1);
406 setenv("HOME", pwd->pw_dir, 1);
407 setenv("SHELL", shell, 1);
416 /* csh strips the first character... */
417 *np = asthem ? "-su" : iscsh == YES ? "_su" : "su";
420 syslog(LOG_NOTICE|LOG_AUTH, "%s to %s%s",
421 username, user, ontty());
427 execv(shell, __DECONST(char * const *, np));
434 fprintf(stderr, "usage: su [-] [-%s] %s[login [args]]\n",
435 KERBEROS_ARG("K") COMMON_ARG("flm"),
452 while (!r && (cp = getusershell()) != NULL)
453 r = strcmp(cp, sh) == 0;
462 static char buf[MAXPATHLEN + 4];
465 p = ttyname(STDERR_FILENO);
467 snprintf(buf, sizeof(buf), " on %s", p);
472 const char superuser[] = "root";
474 /* Authenticate using Kerberos 5.
475 * context -- An initialized krb5_context.
476 * current_user -- The current username.
477 * target_user -- The target account name.
478 * su_principal -- The target krb5_principal.
479 * pass -- The user's password.
480 * Note that a valid keytab in the default location with a host entry
482 * Returns 0 if authentication was successful, or a com_err error code if
486 kerberos5(krb5_context context, const char *current_user,
487 const char *target_user, krb5_principal su_principal,
491 krb5_get_init_creds_opt gic_opt;
492 krb5_verify_init_creds_opt vic_opt;
495 krb5_get_init_creds_opt_init(&gic_opt);
496 krb5_verify_init_creds_opt_init(&vic_opt);
497 rv = krb5_get_init_creds_password(context, &creds, su_principal,
498 pass, NULL, NULL, 0, NULL, &gic_opt);
500 syslog(LOG_NOTICE|LOG_AUTH, "BAD Kerberos5 SU: %s to %s%s: %s",
501 current_user, target_user, ontty(),
502 krb5_get_err_text(context, rv));
505 krb5_verify_init_creds_opt_set_ap_req_nofail(&vic_opt, 1);
506 rv = krb5_verify_init_creds(context, &creds, NULL, NULL, NULL,
508 krb5_free_cred_contents(context, &creds);
510 syslog(LOG_NOTICE|LOG_AUTH, "BAD Kerberos5 SU: %s to %s%s: %s",
511 current_user, target_user, ontty(),
512 krb5_get_err_text(context, rv));
518 /* Determine the target principal given the current user and the target user.
519 * context -- An initialized krb5_context.
520 * target_user -- The target username.
521 * current_user -- The current username.
522 * su_principal_name -- (out) The target principal name.
523 * su_principal -- (out) The target krb5_principal.
525 * When target_user is `root', the su_principal will be a `root
526 * instance', e.g. `luser/root@REA.LM'. Otherwise, the su_principal
527 * will simply be the current user's default principal name. Note that
528 * in any case, if KRB5CCNAME is set and a credentials cache exists, the
529 * principal name found there will be the `starting point', rather than
530 * the current_user parameter.
532 * Returns 0 for success, or a com_err error code on failure.
535 get_su_principal(krb5_context context, const char *target_user,
536 const char *current_user, char **su_principal_name,
537 krb5_principal *su_principal)
539 krb5_principal default_principal;
541 char *principal_name, *ccname, *p;
545 *su_principal = NULL;
546 default_principal = NULL;
547 /* Lower privs while messing about with the credentials
552 rv = seteuid(getuid());
555 p = getenv("KRB5CCNAME");
559 asprintf(&ccname, "%s%lu", KRB5_DEFAULT_CCROOT,
560 (unsigned long)ruid);
564 rv = krb5_cc_resolve(context, ccname, &ccache);
567 rv = krb5_cc_get_principal(context, ccache,
569 krb5_cc_close(context, ccache);
571 default_principal = NULL; /* just to be safe */
576 if (default_principal == NULL) {
577 rv = krb5_make_principal(context, &default_principal, NULL,
580 warnx("Could not determine default principal name.");
584 /* Now that we have some principal, if the target account is
585 * `root', then transform it into a `root' instance, e.g.
586 * `user@REA.LM' -> `user/root@REA.LM'.
588 rv = krb5_unparse_name(context, default_principal, &principal_name);
589 krb5_free_principal(context, default_principal);
591 warnx("krb5_unparse_name: %s", krb5_get_err_text(context, rv));
594 if (strcmp(target_user, superuser) == 0) {
595 p = strrchr(principal_name, '@');
597 warnx("malformed principal name `%s'", principal_name);
598 free(principal_name);
602 asprintf(su_principal_name, "%s/%s@%s", principal_name,
604 free(principal_name);
606 *su_principal_name = principal_name;
607 if (*su_principal_name == NULL)
609 rv = krb5_parse_name(context, *su_principal_name, &default_principal);
611 warnx("krb5_parse_name `%s': %s", *su_principal_name,
612 krb5_get_err_text(context, rv));
613 free(*su_principal_name);
616 *su_principal = default_principal;