shadow/src/su.c
nekral-guest db38a728d1 * configure.in, libmisc/shell.c, libmisc/setupenv.c, src/newgrp.c,
src/su.c: Let the system shell be configurable.
2009-07-22 13:30:06 +00:00

1007 lines
26 KiB
C

/*
* Copyright (c) 1989 - 1994, Julianne Frances Haugh
* Copyright (c) 1996 - 2000, Marek Michałkiewicz
* Copyright (c) 2000 - 2006, Tomasz Kłoczko
* Copyright (c) 2007 - 2009, Nicolas François
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* Some parts substantially derived from an ancestor of:
su for GNU. Run a shell with substitute user and group IDs.
Copyright (C) 1992-2003 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA. */
#include <config.h>
#ident "$Id$"
#include <getopt.h>
#include <grp.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <sys/types.h>
#include "prototypes.h"
#include "defines.h"
#include "pwauth.h"
#include "getdef.h"
#ifdef USE_PAM
#include "pam_defs.h"
#endif /* USE_PAM */
/*@-exitarg@*/
#include "exitcodes.h"
/*
* Assorted #defines to control su's behavior
*/
/*
* Global variables
*/
char *Prog;
/* not needed by sulog.c anymore */
static char name[BUFSIZ];
static char oldname[BUFSIZ];
/* If nonzero, change some environment vars to indicate the user su'd to. */
static bool change_environment;
#ifdef USE_PAM
static pam_handle_t *pamh = NULL;
static bool caught = false;
#endif
extern struct passwd pwent;
/*
* External identifiers
*/
extern char **newenvp;
extern char **environ;
extern size_t newenvc;
/* local function prototypes */
#ifndef USE_PAM
static RETSIGTYPE die (int);
static int iswheel (const char *);
/*
* die - set or reset termio modes.
*
* die() is called before processing begins. signal() is then called
* with die() as the signal handler. If signal later calls die() with a
* signal number, the terminal modes are then reset.
*/
static RETSIGTYPE die (int killed)
{
static TERMIO sgtty;
if (killed)
STTY (0, &sgtty);
else
GTTY (0, &sgtty);
if (killed) {
closelog ();
exit (killed);
}
}
static int iswheel (const char *username)
{
struct group *grp;
grp = getgrnam ("wheel"); /* !USE_PAM, no need for xgetgrnam */
if ( (NULL ==grp)
|| (NULL == grp->gr_mem)) {
return 0;
}
return is_on_list (grp->gr_mem, username);
}
#endif /* !USE_PAM */
/* borrowed from GNU sh-utils' "su.c" */
static bool restricted_shell (const char *shellstr)
{
char *line;
setusershell ();
while ((line = getusershell ()) != NULL) {
if (('#' != *line) && (strcmp (line, shellstr) == 0)) {
endusershell ();
return false;
}
}
endusershell ();
return true;
}
static void su_failure (const char *tty)
{
sulog (tty, false, oldname, name); /* log failed attempt */
#ifdef USE_SYSLOG
if (getdef_bool ("SYSLOG_SU_ENAB")) {
SYSLOG (((0 != pwent.pw_uid) ? LOG_INFO : LOG_NOTICE,
"- %s %s:%s", tty,
('\0' != oldname[0]) ? oldname : "???",
('\0' != name[0]) ? name : "???"));
}
closelog ();
#endif
exit (1);
}
/*
* execve_shell - Execute a shell with execve, or interpret it with
* /bin/sh
*/
void execve_shell (const char *shellstr, char *args[], char *const envp[])
{
int err;
(void) execve (shellstr, (char **) args, envp);
err = errno;
if (access (shellstr, R_OK|X_OK) == 0) {
/*
* Assume this is a shell script (with no shebang).
* Interpret it with /bin/sh
*/
size_t n_args = 0;
char **targs;
while (NULL != args[n_args]) {
n_args++;
}
targs = (char **) xmalloc ((n_args + 2) * sizeof (args[0]));
targs[0] = "sh";
targs[1] = xstrdup (shellstr);
targs[n_args+1] = NULL;
while (1 != n_args) {
targs[n_args] = args[n_args - 1];
n_args--;
}
(void) execve (SHELL, targs, envp);
} else {
errno = err;
}
}
#ifdef USE_PAM
/* Signal handler for parent process later */
static void catch_signals (unused int sig)
{
caught = true;
}
/* This I ripped out of su.c from sh-utils after the Mandrake pam patch
* have been applied. Some work was needed to get it integrated into
* su.c from shadow.
*/
static void run_shell (const char *shellstr, char *args[], bool doshell,
char *const envp[])
{
pid_t child;
sigset_t ourset;
int status;
int ret;
child = fork ();
if (child == 0) { /* child shell */
/*
* PAM_DATA_SILENT is not supported by some modules, and
* there is no strong need to clean up the process space's
* memory since we will either call exec or exit.
pam_end (pamh, PAM_SUCCESS | PAM_DATA_SILENT);
*/
if (doshell) {
(void) shell (shellstr, (char *) args[0], envp);
} else {
execve_shell (shellstr, (char **) args, envp);
}
exit (errno == ENOENT ? E_CMD_NOTFOUND : E_CMD_NOEXEC);
} else if ((pid_t)-1 == child) {
(void) fprintf (stderr, "%s: Cannot fork user shell\n", Prog);
SYSLOG ((LOG_WARN, "Cannot execute %s", shellstr));
closelog ();
exit (1);
}
/* parent only */
sigfillset (&ourset);
if (sigprocmask (SIG_BLOCK, &ourset, NULL) != 0) {
(void) fprintf (stderr, "%s: signal malfunction\n", Prog);
caught = true;
}
if (!caught) {
struct sigaction action;
action.sa_handler = catch_signals;
sigemptyset (&action.sa_mask);
action.sa_flags = 0;
sigemptyset (&ourset);
if ( (sigaddset (&ourset, SIGTERM) != 0)
|| (sigaddset (&ourset, SIGALRM) != 0)
|| (sigaction (SIGTERM, &action, NULL) != 0)
|| (sigprocmask (SIG_UNBLOCK, &ourset, NULL) != 0)
) {
fprintf (stderr,
"%s: signal masking malfunction\n", Prog);
caught = true;
}
}
if (!caught) {
do {
pid_t pid;
pid = waitpid (-1, &status, WUNTRACED);
if (((pid_t)-1 != pid) && (0 != WIFSTOPPED (status))) {
/* The child (shell) was suspended.
* Suspend su. */
kill (getpid (), WSTOPSIG(status));
/* wake child when resumed */
kill (pid, SIGCONT);
}
} while (0 != WIFSTOPPED (status));
}
if (caught) {
fprintf (stderr, "\nSession terminated, killing shell...");
kill (child, SIGTERM);
}
ret = pam_close_session (pamh, 0);
if (PAM_SUCCESS != ret) {
SYSLOG ((LOG_ERR, "pam_close_session: %s",
pam_strerror (pamh, ret)));
fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
(void) pam_end (pamh, ret);
exit (1);
}
ret = pam_end (pamh, PAM_SUCCESS);
if (caught) {
sleep (2);
kill (child, SIGKILL);
fprintf (stderr, " ...killed.\n");
exit (-1);
}
exit ((0 != WIFEXITED (status)) ? WEXITSTATUS (status)
: WTERMSIG (status) + 128);
}
#endif
/*
* usage - print command line syntax and exit
*/
static void usage (void)
{
fputs (_("Usage: su [options] [LOGIN]\n"
"\n"
"Options:\n"
" -c, --command COMMAND pass COMMAND to the invoked shell\n"
" -h, --help display this help message and exit\n"
" -, -l, --login make the shell a login shell\n"
" -m, -p,\n"
" --preserve-environment do not reset environment variables, and\n"
" keep the same shell\n"
" -s, --shell SHELL use SHELL instead of the default in passwd\n"
"\n"), stderr);
exit (E_USAGE);
}
/*
* su - switch user id
*
* su changes the user's ids to the values for the specified user. if
* no new user name is specified, "root" or UID 0 is used by default.
*
* Any additional arguments are passed to the user's shell. In
* particular, the argument "-c" will cause the next argument to be
* interpreted as a command by the common shell programs.
*/
int main (int argc, char **argv)
{
const char *cp;
const char *tty = NULL; /* Name of tty SU is run from */
bool doshell = false;
bool fakelogin = false;
bool amroot = false;
uid_t my_uid;
struct passwd *pw = NULL;
char **envp = environ;
char *shellstr = NULL;
char *command = NULL;
#ifdef USE_PAM
char **envcp;
int ret;
#else /* !USE_PAM */
int err = 0;
RETSIGTYPE (*oldsig) (int);
int is_console = 0;
struct spwd *spwd = 0;
#ifdef SU_ACCESS
char *oldpass;
#endif
#endif /* !USE_PAM */
sanitize_env ();
(void) setlocale (LC_ALL, "");
(void) bindtextdomain (PACKAGE, LOCALEDIR);
(void) textdomain (PACKAGE);
change_environment = true;
/*
* Get the program name. The program name is used as a prefix to
* most error messages.
*/
Prog = Basename (argv[0]);
OPENLOG ("su");
/*
* Process the command line arguments.
*/
{
/*
* Parse the command line options.
*/
int option_index = 0;
int c;
static struct option long_options[] = {
{"command", required_argument, NULL, 'c'},
{"help", no_argument, NULL, 'h'},
{"login", no_argument, NULL, 'l'},
{"preserve-environment", no_argument, NULL, 'p'},
{"shell", required_argument, NULL, 's'},
{NULL, 0, NULL, '\0'}
};
while ((c =
getopt_long (argc, argv, "c:hlmps:", long_options,
&option_index)) != -1) {
switch (c) {
case 'c':
command = optarg;
break;
case 'h':
usage ();
break;
case 'l':
fakelogin = true;
break;
case 'm':
case 'p':
/* This will only have an effect if the target
* user do not have a restricted shell, or if
* su is called by root.
*/
change_environment = false;
break;
case 's':
shellstr = optarg;
break;
default:
usage (); /* NOT REACHED */
}
}
if ((optind < argc) && (strcmp (argv[optind], "-") == 0)) {
fakelogin = true;
optind++;
if ( (optind < argc)
&& (strcmp (argv[optind], "--") == 0)) {
optind++;
}
}
}
initenv ();
my_uid = getuid ();
amroot = (my_uid == 0);
/*
* Get the tty name. Entries will be logged indicating that the user
* tried to change to the named new user from the current terminal.
*/
tty = ttyname (0);
if ((isatty (0) != 0) && (NULL != tty)) {
#ifndef USE_PAM
is_console = console (tty);
#endif
} else {
/*
* Be more paranoid, like su from SimplePAMApps. --marekm
*/
if (!amroot) {
fprintf (stderr,
_("%s: must be run from a terminal\n"), Prog);
exit (1);
}
tty = "???";
}
/*
* The next argument must be either a user ID, or some flag to a
* subshell. Pretty sticky since you can't have an argument which
* doesn't start with a "-" unless you specify the new user name.
* Any remaining arguments will be passed to the user's login shell.
*/
if ((optind < argc) && ('-' != argv[optind][0])) {
STRFCPY (name, argv[optind++]); /* use this login id */
if ((optind < argc) && (strcmp (argv[optind], "--") == 0)) {
optind++;
}
}
if ('\0' == name[0]) { /* use default user */
struct passwd *root_pw = getpwnam ("root");
if ((NULL != root_pw) && (0 == root_pw->pw_uid)) {
(void) strcpy (name, "root");
} else {
root_pw = getpwuid (0);
if (NULL == root_pw) {
SYSLOG ((LOG_CRIT, "There is no UID 0 user."));
su_failure (tty);
}
(void) strcpy (name, root_pw->pw_name);
}
}
doshell = (argc == optind); /* any arguments remaining? */
if (NULL != command) {
doshell = false;
}
/*
* Get the user's real name. The current UID is used to determine
* who has executed su. That user ID must exist.
*/
pw = get_my_pwent ();
if (NULL == pw) {
fprintf (stderr, _("%s: Cannot determine your user name.\n"),
Prog);
SYSLOG ((LOG_WARN, "Cannot determine the user name of the caller (UID %lu)",
(unsigned long) my_uid));
su_failure (tty);
}
STRFCPY (oldname, pw->pw_name);
#ifndef USE_PAM
#ifdef SU_ACCESS
/*
* Sort out the password of user calling su, in case needed later
* -- chris
*/
spwd = getspnam (oldname); /* !USE_PAM, no need for xgetspnam */
if (NULL != spwd) {
pw->pw_passwd = spwd->sp_pwdp;
}
oldpass = xstrdup (pw->pw_passwd);
#endif /* SU_ACCESS */
#else /* USE_PAM */
ret = pam_start ("su", name, &conv, &pamh);
if (PAM_SUCCESS != ret) {
SYSLOG ((LOG_ERR, "pam_start: error %d", ret);
fprintf (stderr, _("%s: pam_start: error %d\n"),
Prog, ret));
exit (1);
}
ret = pam_set_item (pamh, PAM_TTY, (const void *) tty);
if (PAM_SUCCESS == ret) {
ret = pam_set_item (pamh, PAM_RUSER, (const void *) oldname);
}
if (PAM_SUCCESS != ret) {
SYSLOG ((LOG_ERR, "pam_set_item: %s",
pam_strerror (pamh, ret)));
fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
pam_end (pamh, ret);
exit (1);
}
#endif /* USE_PAM */
top:
/*
* This is the common point for validating a user whose name is
* known. It will be reached either by normal processing, or if the
* user is to be logged into a subsystem root.
*
* The password file entries for the user is gotten and the account
* validated.
*/
pw = xgetpwnam (name);
if (NULL == pw) {
(void) fprintf (stderr, _("Unknown id: %s\n"), name);
closelog ();
exit (1);
}
#ifndef USE_PAM
spwd = NULL;
if (strcmp (pw->pw_passwd, SHADOW_PASSWD_STRING) == 0) {
spwd = getspnam (name); /* !USE_PAM, no need for xgetspnam */
if (NULL != spwd) {
pw->pw_passwd = spwd->sp_pwdp;
}
}
#endif /* !USE_PAM */
pwent = *pw;
/* If su is not called by root, and the target user has a restricted
* shell, the environment must be changed.
*/
change_environment |= (restricted_shell (pwent.pw_shell) && !amroot);
/*
* If a new login is being set up, the old environment will be
* ignored and a new one created later on.
* (note: in the case of a subsystem, the shell will be restricted,
* and this won't be executed on the first pass)
*/
if (change_environment && fakelogin) {
/*
* The terminal type will be left alone if it is present in
* the environment already.
*/
cp = getenv ("TERM");
if (NULL != cp) {
addenv ("TERM", cp);
}
/*
* For some terminals COLORTERM seems to be the only way
* for checking for that specific terminal. For instance,
* gnome-terminal sets its TERM as "xterm" but its
* COLORTERM as "gnome-terminal". The COLORTERM variable
* is also of use when running GNU screen since it sets
* TERM to "screen" but doesn't touch COLORTERM.
*/
cp = getenv ("COLORTERM");
if (NULL != cp) {
addenv ("COLORTERM", cp);
}
#ifndef USE_PAM
cp = getdef_str ("ENV_TZ");
if (NULL != cp) {
addenv (('/' == *cp) ? tz (cp) : cp, NULL);
}
/*
* The clock frequency will be reset to the login value if required
*/
cp = getdef_str ("ENV_HZ");
if (NULL != cp) {
addenv (cp, NULL); /* set the default $HZ, if one */
}
#endif /* !USE_PAM */
/*
* Also leave DISPLAY and XAUTHORITY if present, else
* pam_xauth will not work.
*/
cp = getenv ("DISPLAY");
if (NULL != cp) {
addenv ("DISPLAY", cp);
}
cp = getenv ("XAUTHORITY");
if (NULL != cp) {
addenv ("XAUTHORITY", cp);
}
} else {
while (NULL != *envp) {
addenv (*envp, NULL);
envp++;
}
}
#ifndef USE_PAM
/*
* BSD systems only allow "wheel" to SU to root. USG systems don't,
* so we make this a configurable option.
*/
/* The original Shadow 3.3.2 did this differently. Do it like BSD:
*
* - check for UID 0 instead of name "root" - there are systems with
* several root accounts under different names,
*
* - check the contents of /etc/group instead of the current group
* set (you must be listed as a member, GID 0 is not sufficient).
*
* In addition to this traditional feature, we now have complete su
* access control (allow, deny, no password, own password). Thanks
* to Chris Evans <lady0110@sable.ox.ac.uk>.
*/
if (!amroot) {
if ( (0 == pwent.pw_uid)
&& getdef_bool ("SU_WHEEL_ONLY")
&& !iswheel (oldname)) {
fprintf (stderr,
_("You are not authorized to su %s\n"), name);
exit (1);
}
#ifdef SU_ACCESS
switch (check_su_auth (oldname, name)) {
case 0: /* normal su, require target user's password */
break;
case 1: /* require no password */
pwent.pw_passwd = ""; /* XXX warning: const */
break;
case 2: /* require own password */
puts (_("(Enter your own password)"));
pwent.pw_passwd = oldpass;
break;
default: /* access denied (-1) or unexpected value */
fprintf (stderr,
_("You are not authorized to su %s\n"), name);
exit (1);
}
#endif /* SU_ACCESS */
}
#endif /* !USE_PAM */
/* If the user do not want to change the environment,
* use the current SHELL.
* (unless another shell is required by the command line)
*/
if ((NULL == shellstr) && !change_environment) {
shellstr = getenv ("SHELL");
}
/* For users with non null UID, if this user has a restricted
* shell, the shell must be the one specified in /etc/passwd
*/
if ( (NULL != shellstr)
&& !amroot
&& restricted_shell (pwent.pw_shell)) {
shellstr = NULL;
}
/* If the shell is not set at this time, use the shell specified
* in /etc/passwd.
*/
if (NULL == shellstr) {
shellstr = (char *) strdup (pwent.pw_shell);
}
/*
* Set the default shell.
*/
if ((NULL == shellstr) || ('\0' == shellstr[0])) {
shellstr = SHELL;
}
(void) signal (SIGINT, SIG_IGN);
(void) signal (SIGQUIT, SIG_IGN);
#ifdef USE_PAM
ret = pam_authenticate (pamh, 0);
if (PAM_SUCCESS != ret) {
SYSLOG ((LOG_ERR, "pam_authenticate: %s",
pam_strerror (pamh, ret)));
fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
(void) pam_end (pamh, ret);
su_failure (tty);
}
ret = pam_acct_mgmt (pamh, 0);
if (PAM_SUCCESS != ret) {
if (amroot) {
fprintf (stderr, _("%s: %s\n(Ignored)\n"), Prog,
pam_strerror (pamh, ret));
} else if (PAM_NEW_AUTHTOK_REQD == ret) {
ret = pam_chauthtok (pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
if (PAM_SUCCESS != ret) {
SYSLOG ((LOG_ERR, "pam_chauthtok: %s",
pam_strerror (pamh, ret)));
fprintf (stderr, _("%s: %s\n"), Prog,
pam_strerror (pamh, ret));
(void) pam_end (pamh, ret);
su_failure (tty);
}
} else {
SYSLOG ((LOG_ERR, "pam_acct_mgmt: %s",
pam_strerror (pamh, ret)));
fprintf (stderr, _("%s: %s\n"), Prog,
pam_strerror (pamh, ret));
(void) pam_end (pamh, ret);
su_failure (tty);
}
}
#else /* !USE_PAM */
/*
* Set up a signal handler in case the user types QUIT.
*/
die (0);
oldsig = signal (SIGQUIT, die);
/*
* See if the system defined authentication method is being used.
* The first character of an administrator defined method is an '@'
* character.
*/
if (!amroot && pw_auth (pwent.pw_passwd, name, PW_SU, (char *) 0)) {
SYSLOG ((pwent.pw_uid ? LOG_NOTICE : LOG_WARN,
"Authentication failed for %s", name));
fprintf(stderr, _("%s: Authentication failure\n"), Prog);
su_failure (tty);
}
(void) signal (SIGQUIT, oldsig);
/*
* Check to see if the account is expired. root gets to ignore any
* expired accounts, but normal users can't become a user with an
* expired password.
*/
if (!amroot) {
if (NULL == spwd) {
spwd = pwd_to_spwd (&pwent);
}
if (expire (&pwent, spwd)) {
/* !USE_PAM, no need for xgetpwnam */
struct passwd *pwd = getpwnam (name);
/* !USE_PAM, no need for xgetspnam */
spwd = getspnam (name);
if (NULL != pwd) {
pwent = *pwd;
}
}
}
/*
* Check to see if the account permits "su". root gets to ignore any
* restricted accounts, but normal users can't become a user if
* there is a "SU" entry in the /etc/porttime file denying access to
* the account.
*/
if (!amroot) {
if (!isttytime (pwent.pw_name, "SU", time ((time_t *) 0))) {
SYSLOG (((0 != pwent.pw_uid) ? LOG_WARN : LOG_CRIT,
"SU by %s to restricted account %s",
oldname, name));
fprintf(stderr,
_("%s: You are not authorized to su at that time\n"), Prog);
su_failure (tty);
}
}
#endif /* !USE_PAM */
(void) signal (SIGINT, SIG_DFL);
(void) signal (SIGQUIT, SIG_DFL);
cp = getdef_str ((pwent.pw_uid == 0) ? "ENV_SUPATH" : "ENV_PATH");
if (NULL == cp) {
addenv ("PATH=/bin:/usr/bin", NULL);
} else if (strchr (cp, '=') != NULL) {
addenv (cp, NULL);
} else {
addenv ("PATH", cp);
}
if (getenv ("IFS") != NULL) { /* don't export user IFS ... */
addenv ("IFS= \t\n", NULL); /* ... instead, set a safe IFS */
}
/*
* Even if --shell is specified, the subsystem login test is based on
* the shell specified in /etc/passwd (not the one specified with
* --shell, which will be the one executed in the chroot later).
*/
if ('*' == pwent.pw_shell[0]) { /* subsystem root required */
pwent.pw_shell++; /* skip the '*' */
subsystem (&pwent); /* figure out what to execute */
endpwent ();
endspent ();
goto top;
}
sulog (tty, true, oldname, name); /* save SU information */
endpwent ();
endspent ();
#ifdef USE_SYSLOG
if (getdef_bool ("SYSLOG_SU_ENAB")) {
SYSLOG ((LOG_INFO, "+ %s %s:%s", tty,
('\0' != oldname[0]) ? oldname : "???",
('\0' != name[0]) ? name : "???"));
}
#endif
#ifdef USE_PAM
/* set primary group id and supplementary groups */
if (setup_groups (&pwent) != 0) {
pam_end (pamh, PAM_ABORT);
exit (1);
}
/*
* pam_setcred() may do things like resource limits, console groups,
* and much more, depending on the configured modules
*/
ret = pam_setcred (pamh, PAM_ESTABLISH_CRED);
if (PAM_SUCCESS != ret) {
SYSLOG ((LOG_ERR, "pam_setcred: %s", pam_strerror (pamh, ret)));
fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
(void) pam_end (pamh, ret);
exit (1);
}
ret = pam_open_session (pamh, 0);
if (PAM_SUCCESS != ret) {
SYSLOG ((LOG_ERR, "pam_open_session: %s",
pam_strerror (pamh, ret)));
fprintf (stderr, _("%s: %s\n"), Prog, pam_strerror (pamh, ret));
pam_setcred (pamh, PAM_DELETE_CRED);
(void) pam_end (pamh, ret);
exit (1);
}
if (change_environment) {
/* we need to setup the environment *after* pam_open_session(),
* else the UID is changed before stuff like pam_xauth could
* run, and we cannot access /etc/shadow and co
*/
environ = newenvp; /* make new environment active */
/* update environment with all pam set variables */
envcp = pam_getenvlist (pamh);
if (NULL != envcp) {
while (NULL != *envcp) {
addenv (*envcp, NULL);
envcp++;
}
}
}
/* become the new user */
if (change_uid (&pwent) != 0) {
pam_close_session (pamh, 0);
pam_setcred (pamh, PAM_DELETE_CRED);
(void) pam_end (pamh, PAM_ABORT);
exit (1);
}
#else /* !USE_PAM */
environ = newenvp; /* make new environment active */
/* no limits if su from root (unless su must fake login's behavior) */
if (!amroot || fakelogin) {
setup_limits (&pwent);
}
if (setup_uid_gid (&pwent, is_console) != 0) {
exit (1);
}
#endif /* !USE_PAM */
if (change_environment) {
if (fakelogin) {
pwent.pw_shell = shellstr;
setup_env (&pwent);
} else {
addenv ("HOME", pwent.pw_dir);
addenv ("USER", pwent.pw_name);
addenv ("LOGNAME", pwent.pw_name);
addenv ("SHELL", shellstr);
}
}
/*
* This is a workaround for Linux libc bug/feature (?) - the
* /dev/log file descriptor is open without the close-on-exec flag
* and used to be passed to the new shell. There is "fcntl(LogFile,
* F_SETFD, 1)" in libc/misc/syslog.c, but it is commented out (at
* least in 5.4.33). Why? --marekm
*/
closelog ();
/*
* See if the user has extra arguments on the command line. In that
* case they will be provided to the new user's shell as arguments.
*/
if (fakelogin) {
char *arg0;
cp = getdef_str ("SU_NAME");
if (NULL == cp) {
cp = Basename (shellstr);
}
arg0 = xmalloc (strlen (cp) + 2);
arg0[0] = '-';
strcpy (arg0 + 1, cp);
cp = arg0;
} else {
cp = Basename (shellstr);
}
if (!doshell) {
/* Position argv to the remaining arguments */
argv += optind;
if (NULL != command) {
argv -= 2;
argv[0] = "-c";
argv[1] = command;
}
/*
* Use the shell and create an argv
* with the rest of the command line included.
*/
argv[-1] = shellstr;
#ifndef USE_PAM
execve_shell (shellstr, &argv[-1], environ);
err = errno;
(void) fputs (_("No shell\n"), stderr);
SYSLOG ((LOG_WARN, "Cannot execute %s", shellstr));
closelog ();
exit ((ENOENT == err) ? E_CMD_NOTFOUND : E_CMD_NOEXEC);
#else
run_shell (shellstr, &argv[-1], false, environ); /* no return */
#endif
}
#ifndef USE_PAM
err = shell (shellstr, cp, environ);
exit ((ENOENT == err) ? E_CMD_NOTFOUND : E_CMD_NOEXEC);
#else
run_shell (shellstr, &cp, true, environ);
#endif
/* NOT REACHED */
exit (1);
}