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 1.5 2004/06/19 18:55:48 joerg Exp $
39 #include <sys/param.h>
41 #include <sys/resource.h>
56 #include <login_cap.h>
66 static long get_su_principal(krb5_context context, const char *target_user,
67 const char *current_user, char **su_principal_name,
68 krb5_principal *su_principal);
69 static long kerberos5(krb5_context context, const char *current_user,
70 const char *target_user, krb5_principal su_principal,
73 int use_kerberos5 = 1;
77 #define LOGIN_CAP_ARG(x) x
79 #define LOGIN_CAP_ARG(x)
81 #if defined(KERBEROS5)
82 #define KERBEROS_ARG(x) x
84 #define KERBEROS_ARG(x)
86 #define COMMON_ARG(x) x
87 #define ARGSTR "-" COMMON_ARG("flm") LOGIN_CAP_ARG("c:") KERBEROS_ARG("K")
91 static void usage(void);
94 main(int argc, char **argv)
96 extern char **environ;
102 char *p, **g, *user, *shell=NULL, *username, **cleanenv, **nargv, **np;
106 int asme, ch, asthem, fastlogin, prio, i;
107 enum { UNSET, YES, NO } iscsh = UNSET;
113 #if defined(KERBEROS5)
117 char *su_principal_name, *ccname;
118 krb5_context context;
119 krb5_principal su_principal;
121 char shellbuf[MAXPATHLEN];
126 asme = asthem = fastlogin = 0;
128 while((ch = getopt(argc, argv, ARGSTR)) != -1)
130 #if defined(KERBEROS5)
158 user = argv[optind++];
160 if (strlen(user) > MAXLOGNAME - 1) {
161 (void)fprintf(stderr, "su: username too long.\n");
168 if ((nargv = malloc (sizeof (char *) * (argc + 4))) == NULL) {
169 errx(1, "malloc failure");
172 nargv[argc + 3] = NULL;
173 for (i = argc; i >= optind; i--)
174 nargv[i + 3] = argv[i];
179 #if defined(KERBEROS5)
180 k = auth_getval("auth_list");
181 if (k && !strstr(k, "kerberos")) {
184 su_principal_name = NULL;
186 if (krb5_init_context(&context) != 0)
190 prio = getpriority(PRIO_PROCESS, 0);
193 (void)setpriority(PRIO_PROCESS, 0, -2);
194 openlog("su", LOG_CONS, 0);
196 /* get current login name and shell */
198 username = getlogin();
199 if (username == NULL || (pwd = getpwnam(username)) == NULL ||
201 pwd = getpwuid(ruid);
203 errx(1, "who are you?");
204 username = strdup(pwd->pw_name);
206 if (username == NULL)
209 if (pwd->pw_shell != NULL && *pwd->pw_shell != '\0') {
210 /* copy: pwd memory is recycled */
211 shell = strncpy(shellbuf, pwd->pw_shell, sizeof shellbuf);
212 shellbuf[sizeof shellbuf - 1] = '\0';
214 shell = _PATH_BSHELL;
219 /* get target login information, default to root */
220 if ((pwd = getpwnam(user)) == NULL) {
221 errx(1, "unknown login: %s", user);
225 lc = login_getpwclass(pwd);
228 errx(1, "only root may use -c");
229 lc = login_getclass(class);
231 errx(1, "unknown class: %s", class);
236 targetpass = strdup(pwd->pw_passwd);
242 if (get_su_principal(context, user, username,
243 &su_principal_name, &su_principal) != 0 ||
244 !krb5_kuserok(context, su_principal, user)) {
245 warnx("kerberos5: not in %s's ACL.", user);
252 * Only allow those with pw_gid==0 or those listed in
253 * group zero to su to root. If group zero entry is
254 * missing or empty, then allow anyone to su to root.
255 * iswheelsu will only be set if the user is EXPLICITLY
256 * listed in group zero.
258 if (pwd->pw_uid == 0 && (gr = getgrgid((gid_t)0)) &&
259 gr->gr_mem && *(gr->gr_mem))
260 for (g = gr->gr_mem;; ++g) {
266 "you are not in the correct group (%s) to su %s.",
270 if (strcmp(username, *g) == 0) {
278 /* if target requires a password, verify it */
279 if (*pwd->pw_passwd) {
283 pwd = getpwnam(username);
286 p = skey_getpass("Password:", pwd, 1);
287 if (!(!strcmp(pwd->pw_passwd, skey_crypt(p, pwd->pw_passwd, pwd, 1))
289 || (iswheelsu && !strcmp(targetpass, crypt(p,targetpass)))
293 p = getpass("Password:");
294 if (strcmp(pwd->pw_passwd, crypt(p, pwd->pw_passwd))) {
297 if (use_kerberos5 && kerberos5(context,
298 username, user, su_principal, p) == 0)
301 fprintf(stderr, "Sorry\n");
302 syslog(LOG_AUTH|LOG_WARNING,
303 "BAD SU %s to %s%s", username, user,
307 #if defined(KERBEROS5)
313 pwd = getpwnam(user);
317 if (pwd->pw_expire && time(NULL) >= pwd->pw_expire) {
318 fprintf(stderr, "Sorry - account expired\n");
319 syslog(LOG_AUTH|LOG_WARNING,
320 "BAD SU %s to %s%s", username,
327 /* if asme and non-standard target shell, must be root */
328 if (!chshell(pwd->pw_shell) && ruid)
329 errx(1, "permission denied (shell).");
330 } else if (pwd->pw_shell && *pwd->pw_shell) {
331 shell = pwd->pw_shell;
334 shell = _PATH_BSHELL;
338 /* if we're forking a csh, we want to slightly muck the args */
339 if (iscsh == UNSET) {
340 p = strrchr(shell, '/');
345 if ((iscsh = strcmp(p, "csh") ? NO : YES) == NO)
346 iscsh = strcmp(p, "tcsh") ? NO : YES;
349 (void)setpriority(PRIO_PROCESS, 0, prio);
352 /* Set everything now except the environment & umask */
353 setwhat = LOGIN_SETUSER|LOGIN_SETGROUP|LOGIN_SETRESOURCES|LOGIN_SETPRIORITY;
355 * Don't touch resource/priority settings if -m has been
356 * used or -l and -c hasn't, and we're not su'ing to root.
358 if ((asme || (!asthem && class == NULL)) && pwd->pw_uid)
359 setwhat &= ~(LOGIN_SETPRIORITY|LOGIN_SETRESOURCES);
360 if (setusercontext(lc, pwd, pwd->pw_uid, setwhat) < 0)
361 err(1, "setusercontext");
363 /* set permissions */
364 if (setgid(pwd->pw_gid) < 0)
366 if (initgroups(user, pwd->pw_gid))
367 errx(1, "initgroups failed");
368 if (setuid(pwd->pw_uid) < 0)
376 ccname = getenv("KRB5CCNAME");
378 if ((cleanenv = calloc(20, sizeof(char*))) == NULL)
383 /* set the su'd user's environment & umask */
384 setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETPATH|LOGIN_SETUMASK|LOGIN_SETENV);
386 (void)setenv("PATH", _PATH_DEFPATH, 1);
389 (void)setenv("TERM", p, 1);
392 (void)setenv("KRB5CCNAME", ccname, 1);
394 if (chdir(pwd->pw_dir) < 0)
395 errx(1, "no directory");
397 if (asthem || pwd->pw_uid)
398 (void)setenv("USER", pwd->pw_name, 1);
399 (void)setenv("HOME", pwd->pw_dir, 1);
400 (void)setenv("SHELL", shell, 1);
409 /* csh strips the first character... */
410 *np = asthem ? "-su" : iscsh == YES ? "_su" : "su";
413 syslog(LOG_NOTICE|LOG_AUTH, "%s to %s%s",
414 username, user, ontty());
427 (void)fprintf(stderr, "usage: su [-] [-%s] %s[login [args]]\n",
428 KERBEROS_ARG("K") COMMON_ARG("flm"),
445 while (!r && (cp = getusershell()) != NULL)
446 r = strcmp(cp, sh) == 0;
455 static char buf[MAXPATHLEN + 4];
458 p = ttyname(STDERR_FILENO);
460 snprintf(buf, sizeof(buf), " on %s", p);
465 const char superuser[] = "root";
467 /* Authenticate using Kerberos 5.
468 * context -- An initialized krb5_context.
469 * current_user -- The current username.
470 * target_user -- The target account name.
471 * su_principal -- The target krb5_principal.
472 * pass -- The user's password.
473 * Note that a valid keytab in the default location with a host entry
475 * Returns 0 if authentication was successful, or a com_err error code if
479 kerberos5(krb5_context context, const char *current_user,
480 const char *target_user, krb5_principal su_principal,
484 krb5_get_init_creds_opt gic_opt;
485 krb5_verify_init_creds_opt vic_opt;
488 krb5_get_init_creds_opt_init(&gic_opt);
489 krb5_verify_init_creds_opt_init(&vic_opt);
490 rv = krb5_get_init_creds_password(context, &creds, su_principal,
491 pass, NULL, NULL, 0, NULL, &gic_opt);
493 syslog(LOG_NOTICE|LOG_AUTH, "BAD Kerberos5 SU: %s to %s%s: %s",
494 current_user, target_user, ontty(),
495 krb5_get_err_text(context, rv));
498 krb5_verify_init_creds_opt_set_ap_req_nofail(&vic_opt, 1);
499 rv = krb5_verify_init_creds(context, &creds, NULL, NULL, NULL,
501 krb5_free_cred_contents(context, &creds);
503 syslog(LOG_NOTICE|LOG_AUTH, "BAD Kerberos5 SU: %s to %s%s: %s",
504 current_user, target_user, ontty(),
505 krb5_get_err_text(context, rv));
511 /* Determine the target principal given the current user and the target user.
512 * context -- An initialized krb5_context.
513 * target_user -- The target username.
514 * current_user -- The current username.
515 * su_principal_name -- (out) The target principal name.
516 * su_principal -- (out) The target krb5_principal.
518 * When target_user is `root', the su_principal will be a `root
519 * instance', e.g. `luser/root@REA.LM'. Otherwise, the su_principal
520 * will simply be the current user's default principal name. Note that
521 * in any case, if KRB5CCNAME is set and a credentials cache exists, the
522 * principal name found there will be the `starting point', rather than
523 * the current_user parameter.
525 * Returns 0 for success, or a com_err error code on failure.
528 get_su_principal(krb5_context context, const char *target_user,
529 const char *current_user, char **su_principal_name,
530 krb5_principal *su_principal)
532 krb5_principal default_principal;
534 char *principal_name, *ccname, *p;
538 *su_principal = NULL;
539 default_principal = NULL;
540 /* Lower privs while messing about with the credentials
545 rv = seteuid(getuid());
548 p = getenv("KRB5CCNAME");
552 (void)asprintf(&ccname, "%s%lu", KRB5_DEFAULT_CCROOT,
553 (unsigned long)ruid);
556 rv = krb5_cc_resolve(context, ccname, &ccache);
559 rv = krb5_cc_get_principal(context, ccache,
561 krb5_cc_close(context, ccache);
563 default_principal = NULL; /* just to be safe */
568 if (default_principal == NULL) {
569 rv = krb5_make_principal(context, &default_principal, NULL,
572 warnx("Could not determine default principal name.");
576 /* Now that we have some principal, if the target account is
577 * `root', then transform it into a `root' instance, e.g.
578 * `user@REA.LM' -> `user/root@REA.LM'.
580 rv = krb5_unparse_name(context, default_principal, &principal_name);
581 krb5_free_principal(context, default_principal);
583 warnx("krb5_unparse_name: %s", krb5_get_err_text(context, rv));
586 if (strcmp(target_user, superuser) == 0) {
587 p = strrchr(principal_name, '@');
589 warnx("malformed principal name `%s'", principal_name);
590 free(principal_name);
594 (void)asprintf(su_principal_name, "%s/%s@%s", principal_name,
596 free(principal_name);
598 *su_principal_name = principal_name;
599 if (*su_principal_name == NULL)
601 rv = krb5_parse_name(context, *su_principal_name, &default_principal);
603 warnx("krb5_parse_name `%s': %s", *su_principal_name,
604 krb5_get_err_text(context, rv));
605 free(*su_principal_name);
608 *su_principal = default_principal;