2 * Copyright (c) 1989 - 1994, Julianne Frances Haugh
3 * Copyright (c) 1996 - 2000, Marek Michałkiewicz
4 * Copyright (c) 2000 - 2006, Tomasz Kłoczko
5 * Copyright (c) 2007 - 2011, Nicolas François
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the copyright holders or contributors may not be used to
17 * endorse or promote products derived from this software without
18 * specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
23 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 /* Some parts substantially derived from an ancestor of:
34 su for GNU. Run a shell with substitute user and group IDs.
36 Copyright (C) 1992-2003 Free Software Foundation, Inc.
38 This program is free software; you can redistribute it and/or modify
39 it under the terms of the GNU General Public License as published by
40 the Free Software Foundation; either version 2, or (at your option)
43 This program is distributed in the hope that it will be useful,
44 but WITHOUT ANY WARRANTY; without even the implied warranty of
45 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
46 GNU General Public License for more details.
48 You should have received a copy of the GNU General Public License
49 along with this program; if not, write to the Free Software
50 Foundation, Inc., 51 Franklin Street, Fifth Floor,
51 Boston, MA 02110-1301, USA. */
63 #include <sys/types.h>
66 #include <sys/ioctl.h>
67 #include <sys/types.h>
71 #include "prototypes.h"
79 #include "exitcodes.h"
85 static const char *caller_tty = NULL; /* Name of tty SU is run from */
86 static bool caller_is_root = false;
87 static uid_t caller_uid;
89 static int caller_on_console = 0;
91 static char *caller_pass;
94 static bool doshell = false;
95 static bool fakelogin = false;
96 static char *shellstr = NULL;
97 static char *command = NULL;
100 /* not needed by sulog.c anymore */
101 static char name[BUFSIZ];
102 static char caller_name[BUFSIZ];
104 /* If nonzero, change some environment vars to indicate the user su'd to. */
105 static bool change_environment = true;
108 static pam_handle_t *pamh = NULL;
109 static int caught = 0;
110 /* PID of the child, in case it needs to be killed */
111 static pid_t pid_child = 0;
115 * External identifiers
118 extern char **newenvp; /* libmisc/env.c */
119 extern size_t newenvc; /* libmisc/env.c */
121 /* local function prototypes */
123 static void execve_shell (const char *shellname,
127 static RETSIGTYPE kill_child (int unused(s));
128 static void prepare_pam_close_session (void);
130 static RETSIGTYPE die (int);
131 static bool iswheel (const char *);
132 #endif /* !USE_PAM */
133 static bool restricted_shell (const char *shellname);
134 static void su_failure (const char *tty, bool su_to_root);
135 static struct passwd * check_perms (void);
137 static void check_perms_pam (struct passwd *pw);
139 static void check_perms_nopam (struct passwd *pw);
140 #endif /* !USE_PAM */
141 static void save_caller_context (char **argv);
142 static void process_flags (int argc, char **argv);
143 static void set_environment (struct passwd *pw);
147 * die - set or reset termio modes.
149 * die() is called before processing begins. signal() is then called
150 * with die() as the signal handler. If signal later calls die() with a
151 * signal number, the terminal modes are then reset.
153 static RETSIGTYPE die (int killed)
169 static bool iswheel (const char *username)
173 grp = getgrnam ("wheel"); /* !USE_PAM, no need for xgetgrnam */
175 || (NULL == grp->gr_mem)) {
178 return is_on_list (grp->gr_mem, username);
181 static RETSIGTYPE kill_child (int unused(s))
183 if (0 != pid_child) {
184 (void) kill (pid_child, SIGKILL);
185 (void) fputs (_(" ...killed.\n"), stderr);
187 (void) fputs (_(" ...waiting for child to terminate.\n"),
194 /* borrowed from GNU sh-utils' "su.c" */
195 static bool restricted_shell (const char *shellname)
200 while ((line = getusershell ()) != NULL) {
201 if (('#' != *line) && (strcmp (line, shellname) == 0)) {
210 static void su_failure (const char *tty, bool su_to_root)
212 sulog (tty, false, caller_name, name); /* log failed attempt */
214 if (getdef_bool ("SYSLOG_SU_ENAB")) {
215 SYSLOG ((su_to_root ? LOG_NOTICE : LOG_INFO,
217 ('\0' != caller_name[0]) ? caller_name : "???",
218 ('\0' != name[0]) ? name : "???"));
226 * execve_shell - Execute a shell with execve, or interpret it with
229 static void execve_shell (const char *shellname,
234 (void) execve (shellname, (char **) args, envp);
237 if (access (shellname, R_OK|X_OK) == 0) {
239 * Assume this is a shell script (with no shebang).
240 * Interpret it with /bin/sh
244 while (NULL != args[n_args]) {
247 targs = (char **) xmalloc ((n_args + 3) * sizeof (args[0]));
250 targs[2] = xstrdup (shellname);
251 targs[n_args+2] = NULL;
252 while (1 != n_args) {
253 targs[n_args+1] = args[n_args - 1];
257 (void) execve (SHELL, targs, envp);
264 /* Signal handler for parent process later */
265 static void catch_signals (int sig)
271 * prepare_pam_close_session - Fork and wait for the child to close the session
273 * Only the child returns. The parent will wait for the child to
274 * terminate and exit.
276 static void prepare_pam_close_session (void)
283 if (pid_child == 0) { /* child shell */
284 return; /* Only the child will return from pam_create_session */
285 } else if ((pid_t)-1 == pid_child) {
286 (void) fprintf (stderr,
287 _("%s: Cannot fork user shell\n"),
289 SYSLOG ((LOG_WARN, "Cannot execute %s", shellstr));
292 /* Only the child returns. See above. */
296 sigfillset (&ourset);
297 if (sigprocmask (SIG_BLOCK, &ourset, NULL) != 0) {
298 (void) fprintf (stderr,
299 _("%s: signal malfunction\n"),
304 struct sigaction action;
306 action.sa_handler = catch_signals;
307 sigemptyset (&action.sa_mask);
309 sigemptyset (&ourset);
311 if ( (sigaddset (&ourset, SIGTERM) != 0)
312 || (sigaddset (&ourset, SIGALRM) != 0)
313 || (sigaction (SIGTERM, &action, NULL) != 0)
314 || ( !doshell /* handle SIGINT (Ctrl-C), SIGQUIT
315 * (Ctrl-\), and SIGTSTP (Ctrl-Z)
316 * since the child will not control
319 && ( (sigaddset (&ourset, SIGINT) != 0)
320 || (sigaddset (&ourset, SIGQUIT) != 0)
321 || (sigaddset (&ourset, SIGTSTP) != 0)
322 || (sigaction (SIGINT, &action, NULL) != 0)
323 || (sigaction (SIGQUIT, &action, NULL) != 0)
324 || (sigaction (SIGTSTP, &action, NULL) != 0)))
325 || (sigprocmask (SIG_UNBLOCK, &ourset, NULL) != 0)
328 _("%s: signal masking malfunction\n"),
341 pid = waitpid (-1, &status, WUNTRACED);
343 /* When interrupted by signal, the signal will be
344 * forwarded to the child, and termination will be
347 if ( ((pid_t)-1 == pid)
349 && (SIGTSTP == caught)) {
350 /* Except for SIGTSTP, which request to
352 * We will SIGSTOP ourself on the next
355 kill (pid_child, SIGSTOP);
357 } else if ( ((pid_t)-1 != pid)
358 && (0 != WIFSTOPPED (status))) {
359 /* The child (shell) was suspended.
361 kill (getpid (), SIGSTOP);
362 /* wake child when resumed */
370 (void) fputs ("\n", stderr);
371 (void) fputs (_("Session terminated, terminating shell..."),
373 (void) kill (pid_child, caught);
376 ret = pam_close_session (pamh, 0);
377 if (PAM_SUCCESS != ret) {
378 SYSLOG ((LOG_ERR, "pam_close_session: %s",
379 pam_strerror (pamh, ret)));
380 fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
383 (void) pam_setcred (pamh, PAM_DELETE_CRED);
384 (void) pam_end (pamh, PAM_SUCCESS);
387 (void) signal (SIGALRM, kill_child);
390 (void) wait (&status);
391 (void) fputs (_(" ...terminated.\n"), stderr);
394 exit ((0 != WIFEXITED (status)) ? WEXITSTATUS (status)
395 : WTERMSIG (status) + 128);
396 /* Only the child returns. See above. */
401 * usage - print command line syntax and exit
403 static void usage (int status)
405 fputs (_("Usage: su [options] [LOGIN]\n"
408 " -c, --command COMMAND pass COMMAND to the invoked shell\n"
409 " -h, --help display this help message and exit\n"
410 " -, -l, --login make the shell a login shell\n"
412 " --preserve-environment do not reset environment variables, and\n"
413 " keep the same shell\n"
414 " -s, --shell SHELL use SHELL instead of the default in passwd\n"
415 "\n"), (E_SUCCESS != status) ? stderr : stdout);
420 static void check_perms_pam (struct passwd *pw)
423 ret = pam_authenticate (pamh, 0);
424 if (PAM_SUCCESS != ret) {
425 SYSLOG ((LOG_ERR, "pam_authenticate: %s",
426 pam_strerror (pamh, ret)));
427 fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
428 (void) pam_end (pamh, ret);
429 su_failure (caller_tty, 0 == pw->pw_uid);
432 ret = pam_acct_mgmt (pamh, 0);
433 if (PAM_SUCCESS != ret) {
434 if (caller_is_root) {
436 _("%s: %s\n(Ignored)\n"),
437 Prog, pam_strerror (pamh, ret));
438 } else if (PAM_NEW_AUTHTOK_REQD == ret) {
439 ret = pam_chauthtok (pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
440 if (PAM_SUCCESS != ret) {
441 SYSLOG ((LOG_ERR, "pam_chauthtok: %s",
442 pam_strerror (pamh, ret)));
445 Prog, pam_strerror (pamh, ret));
446 (void) pam_end (pamh, ret);
447 su_failure (caller_tty, 0 == pw->pw_uid);
450 SYSLOG ((LOG_ERR, "pam_acct_mgmt: %s",
451 pam_strerror (pamh, ret)));
454 Prog, pam_strerror (pamh, ret));
455 (void) pam_end (pamh, ret);
456 su_failure (caller_tty, 0 == pw->pw_uid);
461 static void check_perms_nopam (struct passwd *pw)
463 struct spwd *spwd = NULL;
464 RETSIGTYPE (*oldsig) (int);
466 if (caller_is_root) {
471 * BSD systems only allow "wheel" to SU to root. USG systems don't,
472 * so we make this a configurable option.
475 /* The original Shadow 3.3.2 did this differently. Do it like BSD:
477 * - check for UID 0 instead of name "root" - there are systems with
478 * several root accounts under different names,
480 * - check the contents of /etc/group instead of the current group
481 * set (you must be listed as a member, GID 0 is not sufficient).
483 * In addition to this traditional feature, we now have complete su
484 * access control (allow, deny, no password, own password). Thanks
485 * to Chris Evans <lady0110@sable.ox.ac.uk>.
488 if ( (0 == pw->pw_uid)
489 && getdef_bool ("SU_WHEEL_ONLY")
490 && !iswheel (caller_name)) {
492 _("You are not authorized to su %s\n"),
496 spwd = getspnam (name); /* !USE_PAM, no need for xgetspnam */
498 if (strcmp (pw->pw_passwd, SHADOW_PASSWD_STRING) == 0) {
500 pw->pw_passwd = spwd->sp_pwdp;
504 switch (check_su_auth (caller_name, name, 0 == pw->pw_uid)) {
505 case 0: /* normal su, require target user's password */
507 case 1: /* require no password */
508 pw->pw_passwd = ""; /* XXX warning: const */
510 case 2: /* require own password */
511 puts (_("(Enter your own password)"));
512 pw->pw_passwd = caller_pass;
514 default: /* access denied (-1) or unexpected value */
516 _("You are not authorized to su %s\n"),
520 #endif /* SU_ACCESS */
522 * Set up a signal handler in case the user types QUIT.
525 oldsig = signal (SIGQUIT, die);
528 * See if the system defined authentication method is being used.
529 * The first character of an administrator defined method is an '@'
532 if (pw_auth (pw->pw_passwd, name, PW_SU, (char *) 0) != 0) {
533 SYSLOG (((pw->pw_uid != 0)? LOG_NOTICE : LOG_WARN,
534 "Authentication failed for %s", name));
535 fprintf(stderr, _("%s: Authentication failure\n"), Prog);
536 su_failure (caller_tty, 0 == pw->pw_uid);
538 (void) signal (SIGQUIT, oldsig);
541 * Check to see if the account is expired. root gets to ignore any
542 * expired accounts, but normal users can't become a user with an
546 (void) expire (pw, spwd);
550 * Check to see if the account permits "su". root gets to ignore any
551 * restricted accounts, but normal users can't become a user if
552 * there is a "SU" entry in the /etc/porttime file denying access to
555 if (!isttytime (name, "SU", time ((time_t *) 0))) {
556 SYSLOG (((0 != pw->pw_uid) ? LOG_WARN : LOG_CRIT,
557 "SU by %s to restricted account %s",
560 _("%s: You are not authorized to su at that time\n"),
562 su_failure (caller_tty, 0 == pw->pw_uid);
565 #endif /* !USE_PAM */
568 * check_perms - check permissions to switch to the user 'name'
570 * In case of subsystem login, the user is first authenticated in the
571 * caller's root subsystem, and then in the user's target subsystem.
573 static struct passwd * check_perms (void)
576 const char *tmp_name;
578 #endif /* !USE_PAM */
580 * The password file entries for the user is gotten and the account
583 struct passwd *pw = xgetpwnam (name);
585 (void) fprintf (stderr,
586 _("No passwd entry for user '%s'\n"), name);
587 SYSLOG ((LOG_ERR, "No passwd entry for user '%s'", name));
588 su_failure (caller_tty, true);
591 (void) signal (SIGINT, SIG_IGN);
592 (void) signal (SIGQUIT, SIG_IGN);
595 check_perms_pam (pw);
596 /* PAM authentication can request a change of account */
597 ret = pam_get_item(pamh, PAM_USER, (const void **) &tmp_name);
598 if (ret != PAM_SUCCESS) {
599 SYSLOG((LOG_ERR, "pam_get_item: internal PAM error\n"));
600 (void) fprintf (stderr,
601 "%s: Internal PAM error retrieving username\n",
603 (void) pam_end (pamh, ret);
604 su_failure (caller_tty, 0 == pw->pw_uid);
606 if (strcmp (name, tmp_name) != 0) {
608 "Change user from '%s' to '%s' as requested by PAM",
610 strncpy (name, tmp_name, sizeof(name) - 1);
611 name[sizeof(name) - 1] = '\0';
612 pw = xgetpwnam (name);
614 (void) fprintf (stderr,
615 _("No passwd entry for user '%s'\n"),
618 "No passwd entry for user '%s'", name));
619 su_failure (caller_tty, true);
623 check_perms_nopam (pw);
624 #endif /* !USE_PAM */
626 (void) signal (SIGINT, SIG_DFL);
627 (void) signal (SIGQUIT, SIG_DFL);
630 * Even if --shell is specified, the subsystem login test is based on
631 * the shell specified in /etc/passwd (not the one specified with
632 * --shell, which will be the one executed in the chroot later).
634 if ('*' == pw->pw_shell[0]) { /* subsystem root required */
635 subsystem (pw); /* change to the subsystem root */
636 endpwent (); /* close the old password databases */
638 return check_perms (); /* authenticate in the subsystem */
645 * save_caller_context - save information from the call context
647 * Save the program's name (Prog), caller's UID (caller_uid /
648 * caller_is_root), name (caller_name), and password (caller_pass),
649 * the TTY (ttyp), and whether su was called from a console
650 * (is_console) for further processing and before they might change.
652 static void save_caller_context (char **argv)
654 struct passwd *pw = NULL;
656 * Get the program name. The program name is used as a prefix to
657 * most error messages.
659 Prog = Basename (argv[0]);
661 caller_uid = getuid ();
662 caller_is_root = (caller_uid == 0);
665 * Get the tty name. Entries will be logged indicating that the user
666 * tried to change to the named new user from the current terminal.
668 caller_tty = ttyname (0);
669 if ((isatty (0) != 0) && (NULL != caller_tty)) {
671 caller_on_console = console (caller_tty);
675 * Be more paranoid, like su from SimplePAMApps. --marekm
677 if (!caller_is_root) {
679 _("%s: must be run from a terminal\n"),
687 * Get the user's real name. The current UID is used to determine
688 * who has executed su. That user ID must exist.
690 pw = get_my_pwent ();
693 _("%s: Cannot determine your user name.\n"),
695 SYSLOG ((LOG_WARN, "Cannot determine the user name of the caller (UID %lu)",
696 (unsigned long) caller_uid));
697 su_failure (caller_tty, true); /* unknown target UID*/
699 STRFCPY (caller_name, pw->pw_name);
704 * Sort out the password of user calling su, in case needed later
707 if (strcmp (pw->pw_passwd, SHADOW_PASSWD_STRING) == 0) {
708 struct spwd *spwd = getspnam (caller_name);
710 pw->pw_passwd = spwd->sp_pwdp;
713 caller_pass = xstrdup (pw->pw_passwd);
714 #endif /* SU_ACCESS */
715 #endif /* !USE_PAM */
719 * process_flags - Process the command line arguments
721 * process_flags() interprets the command line arguments and sets
722 * the values that the user will be created with accordingly. The
723 * values are checked for sanity.
725 static void process_flags (int argc, char **argv)
727 int option_index = 0;
729 static struct option long_options[] = {
730 {"command", required_argument, NULL, 'c'},
731 {"help", no_argument, NULL, 'h'},
732 {"login", no_argument, NULL, 'l'},
733 {"preserve-environment", no_argument, NULL, 'p'},
734 {"shell", required_argument, NULL, 's'},
735 {NULL, 0, NULL, '\0'}
738 while ((c = getopt_long (argc, argv, "c:hlmps:", long_options,
739 &option_index)) != -1) {
752 /* This will only have an effect if the target
753 * user do not have a restricted shell, or if
754 * su is called by root.
756 change_environment = false;
762 usage (E_USAGE); /* NOT REACHED */
766 if ((optind < argc) && (strcmp (argv[optind], "-") == 0)) {
770 && (strcmp (argv[optind], "--") == 0)) {
776 * The next argument must be either a user ID, or some flag to a
777 * subshell. Pretty sticky since you can't have an argument which
778 * doesn't start with a "-" unless you specify the new user name.
779 * Any remaining arguments will be passed to the user's login shell.
781 if ((optind < argc) && ('-' != argv[optind][0])) {
782 STRFCPY (name, argv[optind++]); /* use this login id */
783 if ((optind < argc) && (strcmp (argv[optind], "--") == 0)) {
787 if ('\0' == name[0]) { /* use default user */
788 struct passwd *root_pw = getpwnam ("root");
789 if ((NULL != root_pw) && (0 == root_pw->pw_uid)) {
790 (void) strcpy (name, "root");
792 root_pw = getpwuid (0);
793 if (NULL == root_pw) {
794 SYSLOG ((LOG_CRIT, "There is no UID 0 user."));
795 su_failure (caller_tty, true);
797 (void) strcpy (name, root_pw->pw_name);
801 doshell = (argc == optind); /* any arguments remaining? */
802 if (NULL != command) {
807 static void set_environment (struct passwd *pw)
811 * If a new login is being set up, the old environment will be
812 * ignored and a new one created later on.
814 if (change_environment && fakelogin) {
816 * The terminal type will be left alone if it is present in
817 * the environment already.
819 cp = getenv ("TERM");
825 * For some terminals COLORTERM seems to be the only way
826 * for checking for that specific terminal. For instance,
827 * gnome-terminal sets its TERM as "xterm" but its
828 * COLORTERM as "gnome-terminal". The COLORTERM variable
829 * is also of use when running GNU screen since it sets
830 * TERM to "screen" but doesn't touch COLORTERM.
832 cp = getenv ("COLORTERM");
834 addenv ("COLORTERM", cp);
838 cp = getdef_str ("ENV_TZ");
840 addenv (('/' == *cp) ? tz (cp) : cp, NULL);
844 * The clock frequency will be reset to the login value if required
846 cp = getdef_str ("ENV_HZ");
848 addenv (cp, NULL); /* set the default $HZ, if one */
850 #endif /* !USE_PAM */
853 * Also leave DISPLAY and XAUTHORITY if present, else
854 * pam_xauth will not work.
856 cp = getenv ("DISPLAY");
858 addenv ("DISPLAY", cp);
860 cp = getenv ("XAUTHORITY");
862 addenv ("XAUTHORITY", cp);
865 char **envp = environ;
866 while (NULL != *envp) {
867 addenv (*envp, NULL);
872 cp = getdef_str ((pw->pw_uid == 0) ? "ENV_SUPATH" : "ENV_PATH");
874 addenv ((pw->pw_uid == 0) ? "PATH=/sbin:/bin:/usr/sbin:/usr/bin" : "PATH=/bin:/usr/bin", NULL);
875 } else if (strchr (cp, '=') != NULL) {
881 if (getenv ("IFS") != NULL) { /* don't export user IFS ... */
882 addenv ("IFS= \t\n", NULL); /* ... instead, set a safe IFS */
886 /* we need to setup the environment *after* pam_open_session(),
887 * else the UID is changed before stuff like pam_xauth could
888 * run, and we cannot access /etc/shadow and co
890 environ = newenvp; /* make new environment active */
892 if (change_environment) {
893 /* update environment with all pam set variables */
894 char **envcp = pam_getenvlist (pamh);
896 while (NULL != *envcp) {
897 addenv (*envcp, NULL);
904 environ = newenvp; /* make new environment active */
905 #endif /* !USE_PAM */
907 if (change_environment) {
909 pw->pw_shell = shellstr;
912 addenv ("HOME", pw->pw_dir);
913 addenv ("USER", pw->pw_name);
914 addenv ("LOGNAME", pw->pw_name);
915 addenv ("SHELL", shellstr);
922 * su - switch user id
924 * su changes the user's ids to the values for the specified user. if
925 * no new user name is specified, "root" or UID 0 is used by default.
927 * Any additional arguments are passed to the user's shell. In
928 * particular, the argument "-c" will cause the next argument to be
929 * interpreted as a command by the common shell programs.
931 int main (int argc, char **argv)
934 struct passwd *pw = NULL;
940 (void) setlocale (LC_ALL, "");
941 (void) bindtextdomain (PACKAGE, LOCALEDIR);
942 (void) textdomain (PACKAGE);
944 save_caller_context (argv);
948 process_flags (argc, argv);
953 ret = pam_start ("su", name, &conv, &pamh);
954 if (PAM_SUCCESS != ret) {
955 SYSLOG ((LOG_ERR, "pam_start: error %d", ret);
957 _("%s: pam_start: error %d\n"),
962 ret = pam_set_item (pamh, PAM_TTY, (const void *) caller_tty);
963 if (PAM_SUCCESS == ret) {
964 ret = pam_set_item (pamh, PAM_RUSER, (const void *) caller_name);
966 if (PAM_SUCCESS != ret) {
967 SYSLOG ((LOG_ERR, "pam_set_item: %s",
968 pam_strerror (pamh, ret)));
969 fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
977 /* If the user do not want to change the environment,
978 * use the current SHELL.
979 * (unless another shell is required by the command line)
981 if ((NULL == shellstr) && !change_environment) {
982 shellstr = getenv ("SHELL");
985 /* If su is not called by root, and the target user has a
986 * restricted shell, the environment must be changed and the shell
987 * must be the one specified in /etc/passwd.
990 && restricted_shell (pw->pw_shell)) {
992 change_environment = true;
995 /* If the shell is not set at this time, use the shell specified
998 if (NULL == shellstr) {
999 shellstr = (char *) strdup (pw->pw_shell);
1003 * Set the default shell.
1005 if ((NULL == shellstr) || ('\0' == shellstr[0])) {
1009 sulog (caller_tty, true, caller_name, name); /* save SU information */
1011 if (getdef_bool ("SYSLOG_SU_ENAB")) {
1012 SYSLOG ((LOG_INFO, "+ %s %s:%s", caller_tty,
1013 ('\0' != caller_name[0]) ? caller_name : "???",
1014 ('\0' != name[0]) ? name : "???"));
1019 /* set primary group id and supplementary groups */
1020 if (setup_groups (pw) != 0) {
1021 pam_end (pamh, PAM_ABORT);
1026 * pam_setcred() may do things like resource limits, console groups,
1027 * and much more, depending on the configured modules
1029 ret = pam_setcred (pamh, PAM_ESTABLISH_CRED);
1030 if (PAM_SUCCESS != ret) {
1031 SYSLOG ((LOG_ERR, "pam_setcred: %s", pam_strerror (pamh, ret)));
1032 fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
1033 (void) pam_end (pamh, ret);
1037 ret = pam_open_session (pamh, 0);
1038 if (PAM_SUCCESS != ret) {
1039 SYSLOG ((LOG_ERR, "pam_open_session: %s",
1040 pam_strerror (pamh, ret)));
1041 fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
1042 pam_setcred (pamh, PAM_DELETE_CRED);
1043 (void) pam_end (pamh, ret);
1047 prepare_pam_close_session ();
1049 /* become the new user */
1050 if (change_uid (pw) != 0) {
1053 #else /* !USE_PAM */
1054 /* no limits if su from root (unless su must fake login's behavior) */
1055 if (!caller_is_root || fakelogin) {
1059 if (setup_uid_gid (pw, caller_on_console) != 0) {
1062 #endif /* !USE_PAM */
1064 set_environment (pw);
1067 /* There is no need for a controlling terminal.
1068 * This avoids the callee to inject commands on
1069 * the caller's tty. */
1073 /* When PAM is used, we are on the child */
1076 /* Otherwise, we cannot use setsid */
1077 int fd = open ("/dev/tty", O_RDWR);
1080 err = ioctl (fd, TIOCNOTTY, (char *) 0);
1083 #endif /* USE_PAM */
1086 (void) fprintf (stderr,
1087 _("%s: Cannot drop the controlling terminal\n"),
1094 * PAM_DATA_SILENT is not supported by some modules, and
1095 * there is no strong need to clean up the process space's
1096 * memory since we will either call exec or exit.
1097 pam_end (pamh, PAM_SUCCESS | PAM_DATA_SILENT);
1103 * This is a workaround for Linux libc bug/feature (?) - the
1104 * /dev/log file descriptor is open without the close-on-exec flag
1105 * and used to be passed to the new shell. There is "fcntl(LogFile,
1106 * F_SETFD, 1)" in libc/misc/syslog.c, but it is commented out (at
1107 * least in 5.4.33). Why? --marekm
1112 * See if the user has extra arguments on the command line. In that
1113 * case they will be provided to the new user's shell as arguments.
1118 cp = getdef_str ("SU_NAME");
1120 cp = Basename (shellstr);
1123 arg0 = xmalloc (strlen (cp) + 2);
1125 strcpy (arg0 + 1, cp);
1128 cp = Basename (shellstr);
1133 /* Position argv to the remaining arguments */
1135 if (NULL != command) {
1141 * Use the shell and create an argv
1142 * with the rest of the command line included.
1145 execve_shell (shellstr, &argv[-1], environ);
1147 (void) fprintf (stderr,
1148 _("Cannot execute %s\n"), shellstr);
1151 (void) shell (shellstr, cp, environ);
1154 return (errno == ENOENT ? E_CMD_NOTFOUND : E_CMD_NOEXEC);