blob: 6ed63f1a07d79464d1f22ddbdf05e7fe4db402f2 [file] [log] [blame]
/*
* sulogin
*
* This program gives Linux machines a reasonable secure way to boot single
* user. It forces the user to supply the root password before a shell is
* started. If there is a shadow password file and the encrypted root password
* is "x" the shadow password will be used.
*
* Copyright (C) 1998-2003 Miquel van Smoorenburg.
* Copyright (C) 2012 Karel Zak <kzak@redhat.com>
* Copyright (C) 2012 Werner Fink <werner@suse.de>
*
* 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 of the License, 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 <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <pwd.h>
#include <shadow.h>
#include <termios.h>
#include <errno.h>
#include <getopt.h>
#include <sys/ioctl.h>
#ifdef HAVE_CRYPT_H
# include <crypt.h>
#endif
#ifdef HAVE_LIBSELINUX
# include <selinux/selinux.h>
# include <selinux/get_context_list.h>
#endif
#ifdef __linux__
# include <sys/kd.h>
# include <sys/param.h>
#endif
#include "c.h"
#include "closestream.h"
#include "env.h"
#include "nls.h"
#include "pathnames.h"
#ifdef USE_PLYMOUTH_SUPPORT
# include "plymouth-ctrl.h"
#endif
#include "strutils.h"
#include "ttyutils.h"
#include "sulogin-consoles.h"
#define CONMAX 16
static unsigned int timeout;
static int profile;
static volatile uint32_t openfd; /* Remember higher file descriptors */
static struct sigaction saved_sigint;
static struct sigaction saved_sigtstp;
static struct sigaction saved_sigquit;
static struct sigaction saved_sighup;
static struct sigaction saved_sigchld;
static volatile sig_atomic_t alarm_rised;
static volatile sig_atomic_t sigchild;
#ifndef IUCLC
# define IUCLC 0
#endif
#ifndef WEXITED
# warning "WEXITED is missing, sulogin may not work as expected"
# define WEXITED 0
#endif
static int locked_account_password(const char * const passwd)
{
if (passwd && (*passwd == '*' || *passwd == '!'))
return 1;
return 0;
}
/*
* Fix the tty modes and set reasonable defaults.
*/
static void tcinit(struct console *con)
{
int flags = 0, mode = 0;
struct termios *tio = &con->tio;
const int fd = con->fd;
#ifdef USE_PLYMOUTH_SUPPORT
struct termios lock;
int i = (plymouth_command(MAGIC_PING)) ? PLYMOUTH_TERMIOS_FLAGS_DELAY : 0;
if (i)
plymouth_command(MAGIC_QUIT);
while (i-- > 0) {
/*
* With plymouth the termios flags become changed after this
* function had changed the termios.
*/
memset(&lock, 0, sizeof(struct termios));
if (ioctl(fd, TIOCGLCKTRMIOS, &lock) < 0)
break;
if (!lock.c_iflag && !lock.c_oflag && !lock.c_cflag && !lock.c_lflag)
break;
sleep(1);
}
memset(&lock, 0, sizeof(struct termios));
ioctl(fd, TIOCSLCKTRMIOS, &lock);
#endif
errno = 0;
if (tcgetattr(fd, tio) < 0) {
warn(_("tcgetattr failed"));
con->flags |= CON_NOTTY;
return;
}
/* Handle lines other than virtual consoles here */
#if defined(KDGKBMODE)
if (ioctl(fd, KDGKBMODE, &mode) < 0)
#endif
{
speed_t ispeed, ospeed;
struct winsize ws;
errno = 0;
/* this is a modem line */
con->flags |= CON_SERIAL;
/* Flush input and output queues on modem lines */
tcflush(fd, TCIOFLUSH);
ispeed = cfgetispeed(tio);
ospeed = cfgetospeed(tio);
if (!ispeed) ispeed = TTYDEF_SPEED;
if (!ospeed) ospeed = TTYDEF_SPEED;
tio->c_cflag = CREAD | CS8 | HUPCL | (tio->c_cflag & CLOCAL);
tio->c_iflag = 0;
tio->c_lflag = 0;
tio->c_oflag &= OPOST | ONLCR;
cfsetispeed(tio, ispeed);
cfsetospeed(tio, ospeed);
#ifdef HAVE_STRUCT_TERMIOS_C_LINE
tio->c_line = 0;
#endif
tio->c_cc[VTIME] = 0;
tio->c_cc[VMIN] = 1;
if (ioctl(fd, TIOCGWINSZ, &ws) == 0) {
int update = 0;
if (ws.ws_row == 0) {
ws.ws_row = 24;
update++;
}
if (ws.ws_col == 0) {
ws.ws_col = 80;
update++;
}
if (update)
ignore_result( ioctl(fd, TIOCSWINSZ, &ws) );
}
setlocale(LC_CTYPE, "POSIX");
goto setattr;
}
#if defined(IUTF8) && defined(KDGKBMODE)
/* Handle mode of current keyboard setup, e.g. for UTF-8 */
switch(mode) {
case K_UNICODE:
setlocale(LC_CTYPE, "C.UTF-8");
flags |= UL_TTY_UTF8;
break;
case K_RAW:
case K_MEDIUMRAW:
case K_XLATE:
default:
setlocale(LC_CTYPE, "POSIX");
break;
}
#else
setlocale(LC_CTYPE, "POSIX");
#endif
reset_virtual_console(tio, flags);
setattr:
if (tcsetattr(fd, TCSANOW, tio))
warn(_("tcsetattr failed"));
/* Enable blocking mode for read and write */
if ((flags = fcntl(fd, F_GETFL, 0)) != -1)
ignore_result( fcntl(fd, F_SETFL, flags & ~O_NONBLOCK) );
}
/*
* Finalize the tty modes on modem lines.
*/
static void tcfinal(struct console *con)
{
struct termios *tio = &con->tio;
const int fd = con->fd;
if ((con->flags & CON_SERIAL) == 0) {
xsetenv("TERM", "linux", 1);
return;
}
if (con->flags & CON_NOTTY) {
xsetenv("TERM", "dumb", 1);
return;
}
#if defined (__s390__) || defined (__s390x__)
xsetenv("TERM", "dumb", 1);
#else
xsetenv("TERM", "vt102", 1);
#endif
tio->c_iflag |= (IXON | IXOFF);
tio->c_lflag |= (ICANON | ISIG | ECHO|ECHOE|ECHOK|ECHOKE);
tio->c_oflag |= OPOST;
tio->c_cc[VINTR] = CINTR;
tio->c_cc[VQUIT] = CQUIT;
tio->c_cc[VERASE] = con->cp.erase;
tio->c_cc[VKILL] = con->cp.kill;
tio->c_cc[VEOF] = CEOF;
#ifdef VSWTC
tio->c_cc[VSWTC] = _POSIX_VDISABLE;
#elif defined(VSWTCH)
tio->c_cc[VSWTCH] = _POSIX_VDISABLE;
#endif
tio->c_cc[VSTART] = CSTART;
tio->c_cc[VSTOP] = CSTOP;
tio->c_cc[VSUSP] = CSUSP;
tio->c_cc[VEOL] = _POSIX_VDISABLE;
if (con->cp.eol == CR) {
tio->c_iflag |= ICRNL;
tio->c_iflag &= ~(INLCR|IGNCR);
tio->c_oflag |= ONLCR;
tio->c_oflag &= ~(OCRNL|ONLRET);
}
switch (con->cp.parity) {
default:
case 0:
tio->c_cflag &= ~(PARODD | PARENB);
tio->c_iflag &= ~(INPCK | ISTRIP);
break;
case 1: /* odd parity */
tio->c_cflag |= PARODD;
/* fallthrough */
case 2: /* even parity */
tio->c_cflag |= PARENB;
tio->c_iflag |= (INPCK | ISTRIP);
/* fallthrough */
case (1 | 2): /* no parity bit */
tio->c_cflag &= ~CSIZE;
tio->c_cflag |= CS7;
break;
}
/* Set line attributes */
tcsetattr(fd, TCSANOW, tio);
}
/*
* Called at timeout.
*/
static void alrm_handler(int sig __attribute__((unused)))
{
/* Timeout expired */
alarm_rised++;
}
static void chld_handler(int sig __attribute__((unused)))
{
sigchild++;
}
static void mask_signal(int signal, void (*handler)(int),
struct sigaction *origaction)
{
struct sigaction newaction;
newaction.sa_handler = handler;
sigemptyset(&newaction.sa_mask);
newaction.sa_flags = 0;
sigaction(signal, &newaction, origaction);
}
static void unmask_signal(int signal, struct sigaction *sa)
{
sigaction(signal, sa, NULL);
}
/*
* See if an encrypted password is valid. The encrypted password is checked for
* traditional-style DES and FreeBSD-style MD5 encryption.
*/
static int valid(const char *pass)
{
const char *s;
char id[5];
size_t len;
off_t off;
if (pass[0] == 0)
return 1;
if (pass[0] != '$')
goto check_des;
/*
* up to 4 bytes for the signature e.g. $1$
*/
for (s = pass+1; *s && *s != '$'; s++);
if (*s++ != '$')
return 0;
if ((off = (off_t)(s-pass)) > 4 || off < 3)
return 0;
memset(id, '\0', sizeof(id));
strncpy(id, pass, off);
/*
* up to 16 bytes for the salt
*/
for (; *s && *s != '$'; s++);
if (*s++ != '$')
return 0;
if ((off_t)(s-pass) > 16)
return 0;
len = strlen(s);
/*
* the MD5 hash (128 bits or 16 bytes) encoded in base64 = 22 bytes
*/
if ((strcmp(id, "$1$") == 0) && (len < 22 || len > 24))
return 0;
/*
* the SHA-256 hash 43 bytes
*/
if ((strcmp(id, "$5$") == 0) && (len < 42 || len > 44))
return 0;
/*
* the SHA-512 hash 86 bytes
*/
if ((strcmp(id, "$6$") == 0) && (len < 85 || len > 87))
return 0;
/*
* e.g. Blowfish hash
*/
return 1;
check_des:
if (strlen(pass) != 13)
return 0;
for (s = pass; *s; s++) {
if ((*s < '0' || *s > '9') &&
(*s < 'a' || *s > 'z') &&
(*s < 'A' || *s > 'Z') &&
*s != '.' && *s != '/')
return 0;
}
return 1;
}
/*
* Set a variable if the value is not NULL.
*/
static inline void set(char **var, char *val)
{
if (val)
*var = val;
}
/*
* Get the root password entry.
*/
static struct passwd *getrootpwent(int try_manually)
{
static struct passwd pwd;
struct passwd *pw;
struct spwd *spw;
FILE *fp;
static char line[2 * BUFSIZ];
static char sline[2 * BUFSIZ];
char *p;
/*
* First, we try to get the password the standard way using normal
* library calls.
*/
if ((pw = getpwnam("root")) &&
!strcmp(pw->pw_passwd, "x") &&
(spw = getspnam("root")))
pw->pw_passwd = spw->sp_pwdp;
if (pw || !try_manually)
return pw;
/*
* If we come here, we could not retrieve the root password through
* library calls and we try to read the password and shadow files
* manually.
*/
pwd.pw_name = "root";
pwd.pw_passwd = "";
pwd.pw_gecos = "Super User";
pwd.pw_dir = "/";
pwd.pw_shell = "";
pwd.pw_uid = 0;
pwd.pw_gid = 0;
if ((fp = fopen(_PATH_PASSWD, "r")) == NULL) {
warn(_("cannot open %s"), _PATH_PASSWD);
return &pwd;
}
/*
* Find root in the password file.
*/
while ((p = fgets(line, sizeof(line), fp)) != NULL) {
if (strncmp(line, "root:", 5) != 0)
continue;
p += 5;
set(&pwd.pw_passwd, strsep(&p, ":"));
strsep(&p, ":");
strsep(&p, ":");
set(&pwd.pw_gecos, strsep(&p, ":"));
set(&pwd.pw_dir, strsep(&p, ":"));
set(&pwd.pw_shell, strsep(&p, "\n"));
p = line;
break;
}
fclose(fp);
/*
* If the encrypted password is valid or not found, return.
*/
if (p == NULL) {
warnx(_("%s: no entry for root\n"), _PATH_PASSWD);
return &pwd;
}
if (valid(pwd.pw_passwd))
return &pwd;
/*
* The password is invalid. If there is a shadow password, try it.
*/
*pwd.pw_passwd = '\0';
if ((fp = fopen(_PATH_SHADOW_PASSWD, "r")) == NULL) {
warn(_("cannot open %s"), _PATH_PASSWD);
return &pwd;
}
while ((p = fgets(sline, sizeof(sline), fp)) != NULL) {
if (strncmp(sline, "root:", 5) != 0)
continue;
p += 5;
set(&pwd.pw_passwd, strsep(&p, ":"));
break;
}
fclose(fp);
/*
* If the password is still invalid, NULL it, and return.
*/
if (p == NULL) {
warnx(_("%s: no entry for root"), _PATH_SHADOW_PASSWD);
*pwd.pw_passwd = '\0';
}
/* locked account passwords are valid too */
if (!locked_account_password(pwd.pw_passwd) && !valid(pwd.pw_passwd)) {
warnx(_("%s: root password garbled"), _PATH_SHADOW_PASSWD);
*pwd.pw_passwd = '\0';
}
return &pwd;
}
/*
* Ask by prompt for the password.
*/
static void doprompt(const char *crypted, struct console *con, int deny)
{
struct termios tty;
if (con->flags & CON_SERIAL) {
tty = con->tio;
/*
* For prompting: map NL in output to CR-NL
* otherwise we may see stairs in the output.
*/
tty.c_oflag |= (ONLCR | OPOST);
tcsetattr(con->fd, TCSADRAIN, &tty);
}
if (!con->file) {
con->file = fdopen(con->fd, "r+");
if (!con->file)
goto err;
}
if (deny)
fprintf(con->file, _("\nCannot open access to console, the root account is locked.\n"
"See sulogin(8) man page for more details.\n\n"
"Press Enter to continue.\n"));
else {
#if defined(USE_ONELINE)
if (crypted[0] && !locked_account_password(crypted))
fprintf(con->file, _("Give root password for login: "));
else
fprintf(con->file, _("Press Enter for login: "));
#else
if (crypted[0] && !locked_account_password(crypted))
fprintf(con->file, _("Give root password for maintenance\n"));
else
fprintf(con->file, _("Press Enter for maintenance\n"));
fprintf(con->file, _("(or press Control-D to continue): "));
#endif
}
fflush(con->file);
err:
if (con->flags & CON_SERIAL)
tcsetattr(con->fd, TCSADRAIN, &con->tio);
}
/*
* Make sure to have an own session and controlling terminal
*/
static void setup(struct console *con)
{
int fd = con->fd;
const pid_t pid = getpid(), pgrp = getpgid(0), ppgrp =
getpgid(getppid()), ttypgrp = tcgetpgrp(fd);
if (con->flags & CON_NOTTY)
return;
/*
* Only go through this trouble if the new
* tty doesn't fall in this process group.
*/
if (pgrp != ttypgrp && ppgrp != ttypgrp) {
if (pid != getsid(0)) {
if (pid == getpgid(0))
setpgid(0, getpgid(getppid()));
setsid();
}
mask_signal(SIGHUP, SIG_IGN, &saved_sighup);
if (ttypgrp > 0)
ioctl(STDIN_FILENO, TIOCNOTTY, (char *)1);
unmask_signal(SIGHUP, &saved_sighup);
if (fd > STDIN_FILENO) close(STDIN_FILENO);
if (fd > STDOUT_FILENO) close(STDOUT_FILENO);
if (fd > STDERR_FILENO) close(STDERR_FILENO);
ioctl(fd, TIOCSCTTY, (char *)1);
tcsetpgrp(fd, ppgrp);
}
dup2(fd, STDIN_FILENO);
dup2(fd, STDOUT_FILENO);
dup2(fd, STDERR_FILENO);
con->fd = STDIN_FILENO;
for (fd = STDERR_FILENO+1; fd < 32; fd++) {
if (openfd & (1<<fd)) {
close(fd);
openfd &= ~(1<<fd);
}
}
}
/*
* Ask for the password. Note that there is no default timeout as we normally
* skip this during boot.
*/
static const char *getpasswd(struct console *con)
{
struct sigaction sa;
struct termios tty;
static char pass[128], *ptr;
struct chardata *cp;
const char *ret = pass;
unsigned char tc;
char c, ascval;
int eightbit;
const int fd = con->fd;
if (con->flags & CON_NOTTY)
goto out;
cp = &con->cp;
tty = con->tio;
tty.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
tty.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP|ISIG);
tc = (tcsetattr(fd, TCSAFLUSH, &tty) == 0);
sigemptyset(&sa.sa_mask);
sa.sa_handler = alrm_handler;
sa.sa_flags = 0;
sigaction(SIGALRM, &sa, NULL);
if (timeout)
alarm(timeout);
ptr = &pass[0];
cp->eol = *ptr = '\0';
eightbit = ((con->flags & CON_SERIAL) == 0 || (tty.c_cflag & (PARODD|PARENB)) == 0);
while (cp->eol == '\0') {
if (read(fd, &c, 1) < 1) {
if (errno == EINTR || errno == EAGAIN) {
if (alarm_rised) {
ret = NULL;
goto quit;
}
xusleep(250000);
continue;
}
ret = NULL;
switch (errno) {
case 0:
case EIO:
case ESRCH:
case EINVAL:
case ENOENT:
break;
default:
warn(_("cannot read %s"), con->tty);
break;
}
goto quit;
}
if (eightbit)
ascval = c;
else if (c != (ascval = (c & 0177))) {
uint32_t bits, mask;
for (bits = 1, mask = 1; mask & 0177; mask <<= 1) {
if (mask & ascval)
bits++;
}
cp->parity |= ((bits & 1) ? 1 : 2);
}
switch (ascval) {
case 0:
*ptr = '\0';
goto quit;
case CR:
case NL:
*ptr = '\0';
cp->eol = ascval;
break;
case BS:
case CERASE:
cp->erase = ascval;
if (ptr > &pass[0])
ptr--;
break;
case CKILL:
cp->kill = ascval;
while (ptr > &pass[0])
ptr--;
break;
case CEOF:
ret = NULL;
goto quit;
default:
if ((size_t)(ptr - &pass[0]) >= (sizeof(pass) -1 )) {
fprintf(stderr, "sulogin: input overrun at %s\n\r", con->tty);
ret = NULL;
goto quit;
}
*ptr++ = ascval;
break;
}
}
quit:
alarm(0);
if (tc)
tcsetattr(fd, TCSAFLUSH, &con->tio);
tcfinal(con);
printf("\r\n");
out:
return ret;
}
/*
* Password was OK, execute a shell.
*/
static void sushell(struct passwd *pwd)
{
char shell[PATH_MAX];
char home[PATH_MAX];
char const *p;
char const *su_shell;
/*
* Set directory and shell.
*/
if (chdir(pwd->pw_dir) != 0) {
warn(_("%s: change directory failed"), pwd->pw_dir);
printf(_("Logging in with home = \"/\".\n"));
if (chdir("/") != 0)
warn(_("change directory to system root failed"));
}
if ((p = getenv("SUSHELL")) != NULL)
su_shell = p;
else if ((p = getenv("sushell")) != NULL)
su_shell = p;
else {
if (pwd->pw_shell[0])
su_shell = pwd->pw_shell;
else
su_shell = "/bin/sh";
}
if ((p = strrchr(su_shell, '/')) == NULL)
p = su_shell;
else
p++;
snprintf(shell, sizeof(shell), profile ? "-%s" : "%s", p);
/*
* Set some important environment variables.
*/
if (getcwd(home, sizeof(home)) == NULL)
strcpy(home, "/");
xsetenv("HOME", home, 1);
xsetenv("LOGNAME", "root", 1);
xsetenv("USER", "root", 1);
if (!profile)
xsetenv("SHLVL","0",1);
/*
* Try to execute a shell.
*/
xsetenv("SHELL", su_shell, 1);
unmask_signal(SIGINT, &saved_sigint);
unmask_signal(SIGTSTP, &saved_sigtstp);
unmask_signal(SIGQUIT, &saved_sigquit);
mask_signal(SIGHUP, SIG_DFL, NULL);
#ifdef HAVE_LIBSELINUX
if (is_selinux_enabled() > 0) {
char *scon = NULL;
char *seuser = NULL;
char *level = NULL;
if (getseuserbyname("root", &seuser, &level) == 0) {
if (get_default_context_with_level(seuser, level, 0, &scon) == 0) {
if (setexeccon(scon) != 0)
warnx(_("setexeccon failed"));
freecon(scon);
}
}
free(seuser);
free(level);
}
#endif
execl(su_shell, shell, (char *)NULL);
warn(_("failed to execute %s"), su_shell);
xsetenv("SHELL", "/bin/sh", 1);
execl("/bin/sh", profile ? "-sh" : "sh", (char *)NULL);
warn(_("failed to execute %s"), "/bin/sh");
}
static void usage(void)
{
FILE *out = stdout;
fputs(USAGE_HEADER, out);
fprintf(out, _(
" %s [options] [tty device]\n"), program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("Single-user login.\n"), out);
fputs(USAGE_OPTIONS, out);
fputs(_(" -p, --login-shell start a login shell\n"
" -t, --timeout <seconds> max time to wait for a password (default: no limit)\n"
" -e, --force examine password files directly if getpwnam(3) fails\n"),
out);
fputs(USAGE_SEPARATOR, out);
printf(USAGE_HELP_OPTIONS(26));
printf(USAGE_MAN_TAIL("sulogin(8)"));
exit(EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
struct list_head *ptr, consoles;
struct console *con;
char *tty = NULL;
struct passwd *pwd;
const struct timespec sigwait = { .tv_sec = 0, .tv_nsec = 50000000 };
siginfo_t status = { 0 };
sigset_t set;
int c, reconnect = 0;
int opt_e = 0;
int wait = 0;
pid_t pid;
static const struct option longopts[] = {
{ "login-shell", no_argument, NULL, 'p' },
{ "timeout", required_argument, NULL, 't' },
{ "force", no_argument, NULL, 'e' },
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V' },
{ NULL, 0, NULL, 0 }
};
INIT_LIST_HEAD(&consoles);
/*
* If we are init we need to set up an own session.
*/
if ((pid = getpid()) == 1) {
setsid();
ignore_result( ioctl(STDIN_FILENO, TIOCSCTTY, (char *) 1) );
}
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
close_stdout_atexit();
/*
* See if we have a timeout flag.
*/
while ((c = getopt_long(argc, argv, "ehpt:V", longopts, NULL)) != -1) {
switch(c) {
case 't':
timeout = strtou32_or_err(optarg, _("invalid timeout argument"));
break;
case 'p':
profile = 1;
break;
case 'e':
opt_e = 1;
break;
case 'V':
print_version(EXIT_SUCCESS);
case 'h':
usage();
default:
/* Do not exit! getopt prints a warning. */
break;
}
}
if (geteuid() != 0)
errx(EXIT_FAILURE, _("only superuser can run this program"));
mask_signal(SIGQUIT, SIG_IGN, &saved_sigquit);
mask_signal(SIGTSTP, SIG_IGN, &saved_sigtstp);
mask_signal(SIGINT, SIG_IGN, &saved_sigint);
mask_signal(SIGHUP, SIG_IGN, &saved_sighup);
emergency_do_mounts();
atexit( emergency_do_umounts );
/*
* See if we need to open an other tty device.
*/
if (optind < argc)
tty = argv[optind];
if (!tty || *tty == '\0')
tty = getenv("CONSOLE");
/*
* Detect possible consoles, use stdin as fallback.
* If an optional tty is given, reconnect it to stdin.
*/
reconnect = detect_consoles(tty, STDIN_FILENO, &consoles);
/*
* If previous stdin was not the specified tty and therefore reconnected
* to the specified tty also reconnect stdout and stderr.
*/
if (reconnect) {
if (isatty(STDOUT_FILENO) == 0)
dup2(STDOUT_FILENO, STDIN_FILENO);
if (isatty(STDERR_FILENO) == 0)
dup2(STDOUT_FILENO, STDERR_FILENO);
}
/*
* Should not happen
*/
if (list_empty(&consoles)) {
if (!errno)
errno = ENOENT;
err(EXIT_FAILURE, _("cannot open console"));
}
/*
* Get the root password.
*/
if ((pwd = getrootpwent(opt_e)) == NULL) {
warnx(_("cannot open password database"));
sleep(2);
return EXIT_FAILURE;
}
/*
* Ask for the password on the consoles.
*/
list_for_each(ptr, &consoles) {
con = list_entry(ptr, struct console, entry);
if (con->id >= CONMAX)
break;
if (con->fd >= 0) {
openfd |= (1 << con->fd);
tcinit(con);
continue;
}
if ((con->fd = open(con->tty, O_RDWR | O_NOCTTY | O_NONBLOCK)) < 0)
continue;
openfd |= (1 << con->fd);
tcinit(con);
}
ptr = (&consoles)->next;
if (ptr->next == &consoles) {
con = list_entry(ptr, struct console, entry);
goto nofork;
}
mask_signal(SIGCHLD, chld_handler, &saved_sigchld);
do {
con = list_entry(ptr, struct console, entry);
if (con->id >= CONMAX)
break;
switch ((con->pid = fork())) {
case 0:
mask_signal(SIGCHLD, SIG_DFL, NULL);
nofork:
setup(con);
while (1) {
const char *passwd = pwd->pw_passwd;
const char *answer;
int doshell = 0;
int deny = !opt_e && locked_account_password(pwd->pw_passwd);
doprompt(passwd, con, deny);
if ((answer = getpasswd(con)) == NULL)
break;
if (deny)
exit(EXIT_FAILURE);
/* no password or locked account */
if (!passwd[0] || locked_account_password(passwd))
doshell++;
else {
const char *cryptbuf;
cryptbuf = crypt(answer, passwd);
if (cryptbuf == NULL)
warn(_("crypt failed"));
else if (strcmp(cryptbuf, pwd->pw_passwd) == 0)
doshell++;
}
if (doshell) {
/* sushell() unmask signals */
sushell(pwd);
mask_signal(SIGQUIT, SIG_IGN, &saved_sigquit);
mask_signal(SIGTSTP, SIG_IGN, &saved_sigtstp);
mask_signal(SIGINT, SIG_IGN, &saved_sigint);
fprintf(stderr, _("cannot execute su shell\n\n"));
break;
}
fprintf(stderr, _("Login incorrect\n\n"));
}
if (alarm_rised) {
tcfinal(con);
warnx(_("Timed out\n\n"));
}
/*
* User pressed Control-D.
*/
exit(0);
case -1:
warn(_("fork failed"));
/* fallthrough */
default:
break;
}
ptr = ptr->next;
} while (ptr != &consoles);
do {
int ret;
status.si_pid = 0;
ret = waitid(P_ALL, 0, &status, WEXITED);
if (ret == 0)
break;
if (ret < 0) {
if (errno == ECHILD)
break;
if (errno == EINTR)
continue;
}
errx(EXIT_FAILURE, _("cannot wait on su shell\n\n"));
} while (1);
list_for_each(ptr, &consoles) {
con = list_entry(ptr, struct console, entry);
if (con->fd < 0)
continue;
if (con->pid < 0)
continue;
if (con->pid == status.si_pid)
con->pid = -1;
else {
kill(con->pid, SIGTERM);
wait++;
}
}
sigemptyset(&set);
sigaddset(&set, SIGCHLD);
do {
int signum, ret;
if (!wait)
break;
status.si_pid = 0;
ret = waitid(P_ALL, 0, &status, WEXITED|WNOHANG);
if (ret < 0) {
if (errno == ECHILD)
break;
if (errno == EINTR)
continue;
}
if (!ret && status.si_pid > 0) {
list_for_each(ptr, &consoles) {
con = list_entry(ptr, struct console, entry);
if (con->fd < 0)
continue;
if (con->pid < 0)
continue;
if (con->pid == status.si_pid) {
con->pid = -1;
wait--;
}
}
continue;
}
signum = sigtimedwait(&set, NULL, &sigwait);
if (signum != SIGCHLD && signum < 0 && errno == EAGAIN)
break;
} while (1);
mask_signal(SIGCHLD, SIG_DFL, NULL);
return EXIT_SUCCESS;
}