1 files changed, 609 insertions, 0 deletions

diff --git a/login-utils/sulogin.c b/login-utils/sulogin.c
new file mode 100644
index 0000000..d7d44b6
--- /dev/null
+++ b/login-utils/sulogin.c
@@ -0,0 +1,609 @@
+/*
+ * 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>
+ *
+ * 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/types.h>
+#include <sys/stat.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
+
+#include "c.h"
+#include "closestream.h"
+#include "nls.h"
+#include "pathnames.h"
+#include "strutils.h"
+#include "ttyutils.h"
+
+static unsigned int timeout;
+static int profile;
+
+struct sigaction saved_sigint;
+struct sigaction saved_sigtstp;
+struct sigaction saved_sigquit;
+
+/*
+ * Called at timeout.
+ */
+static void alrm_handler(int sig __attribute__((unused)))
+{
+	return;
+}
+
+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, NULL, origaction);
+	sigaction(signal, &newaction, NULL);
+}
+
+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[256];
+	static char sline[256];
+	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, 256, 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.
+	 */
+	strcpy(pwd.pw_passwd, "");
+	if ((fp = fopen(_PATH_SHADOW_PASSWD, "r")) == NULL) {
+		warn(_("cannot open %s"), _PATH_PASSWD);
+		return &pwd;
+	}
+	while ((p = fgets(sline, 256, 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);
+		strcpy(pwd.pw_passwd, "");
+	}
+	if (!valid(pwd.pw_passwd)) {
+		warnx(_("%s: root password garbled"), _PATH_SHADOW_PASSWD);
+		strcpy(pwd.pw_passwd, "");
+	}
+	return &pwd;
+}
+
+/*
+ * Ask for the password. Note that there is no default timeout as we normally
+ * skip this during boot.
+ */
+static char *getpasswd(char *crypted)
+{
+	struct sigaction sa;
+	struct termios old, tty;
+	static char pass[128];
+	char *ret = pass;
+	size_t i;
+
+	if (crypted[0])
+		printf(_("Give root password for maintenance\n"));
+	else
+		printf(_("Press enter for maintenance"));
+	printf(_("(or type Control-D to continue): "));
+	fflush(stdout);
+
+	tcgetattr(0, &old);
+	tcgetattr(0, &tty);
+	tty.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
+	tty.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
+	tcsetattr(0, TCSANOW, &tty);
+
+	pass[sizeof(pass) - 1] = 0;
+
+	sa.sa_handler = alrm_handler;
+	sa.sa_flags = 0;
+	sigaction(SIGALRM, &sa, NULL);
+	if (timeout)
+		alarm(timeout);
+
+	if (read(0, pass, sizeof(pass) - 1) <= 0)
+		ret = NULL;
+	else {
+		for (i = 0; i < sizeof(pass) && pass[i]; i++)
+			if (pass[i] == '\r' || pass[i] == '\n') {
+				pass[i] = 0;
+				break;
+			}
+	}
+	alarm(0);
+	tcsetattr(0, TCSANOW, &old);
+	printf("\n");
+
+	return ret;
+}
+
+/*
+ * Password was OK, execute a shell.
+ */
+static void sushell(struct passwd *pwd)
+{
+	char shell[PATH_MAX];
+	char home[PATH_MAX];
+	char *p;
+	char *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)
+		setenv("HOME", home, 1);
+
+	setenv("LOGNAME", "root", 1);
+	setenv("USER", "root", 1);
+	if (!profile)
+		setenv("SHLVL","0",1);
+
+	/*
+	 * Try to execute a shell.
+	 */
+	setenv("SHELL", su_shell, 1);
+	unmask_signal(SIGINT, &saved_sigint);
+	unmask_signal(SIGTSTP, &saved_sigtstp);
+	unmask_signal(SIGQUIT, &saved_sigquit);
+
+#ifdef HAVE_LIBSELINUX
+	if (is_selinux_enabled() > 0) {
+		security_context_t 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, NULL);
+	warn(_("%s: exec failed"), su_shell);
+
+	setenv("SHELL", "/bin/sh", 1);
+	execl("/bin/sh", profile ? "-sh" : "sh", NULL);
+	warn(_("%s: exec failed"), "/bin/sh");
+}
+
+static void fixtty(void)
+{
+	struct termios tp;
+	int x = 0, fl = 0;
+
+	/* Skip serial console */
+	if (ioctl(STDIN_FILENO, TIOCMGET, (char *) &x) == 0)
+		return;
+
+#if defined(IUTF8) && defined(KDGKBMODE)
+	/* Detect mode of current keyboard setup, e.g. for UTF-8 */
+	if (ioctl(STDIN_FILENO, KDGKBMODE, &x) == 0 && x == K_UNICODE) {
+		setlocale(LC_CTYPE, "C.UTF-8");
+		fl |= UL_TTY_UTF8;
+	}
+#else
+	setlocale(LC_CTYPE, "POSIX");
+#endif
+	memset(&tp, 0, sizeof(struct termios));
+	if (tcgetattr(STDIN_FILENO, &tp) < 0) {
+		warn(_("tcgetattr failed"));
+		return;
+	}
+
+	reset_virtual_console(&tp, fl);
+
+	if (tcsetattr(0, TCSADRAIN, &tp))
+		warn(_("tcsetattr failed"));
+}
+
+static void usage(FILE *out)
+{
+	fputs(USAGE_HEADER, out);
+	fprintf(out, _(
+		" %s [options] [tty device]\n"), program_invocation_short_name);
+
+	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);
+	fputs(USAGE_HELP, out);
+	fputs(USAGE_VERSION, out);
+	fprintf(out, USAGE_MAN_TAIL("sulogin(8)"));
+}
+
+int main(int argc, char **argv)
+{
+	char *tty = NULL;
+	char *p;
+	struct passwd *pwd;
+	int c, fd = -1;
+	int opt_e = 0;
+	pid_t pid, pgrp, ppgrp, ttypgrp;
+	struct sigaction saved_sighup;
+
+	static const struct option longopts[] = {
+		{ "login-shell",  0, 0, 'p' },
+		{ "timeout",      1, 0, 't' },
+		{ "force",        0, 0, 'e' },
+		{ "help",         0, 0, 'h' },
+		{ "version",      0, 0, 'V' },
+		{ NULL,           0, 0, 0 }
+	};
+
+	setlocale(LC_ALL, "");
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+	atexit(close_stdout);
+
+	/*
+	 * 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':
+			printf(UTIL_LINUX_VERSION);
+			return EXIT_SUCCESS;
+		case 'h':
+			usage(stdout);
+			return EXIT_SUCCESS;
+		default:
+			usage(stderr);
+			/* Do not exit! */
+			break;
+		}
+	}
+
+	if (geteuid() != 0)
+		errx(EXIT_FAILURE, _("only root can run this program."));
+
+	/*
+	 * See if we need to open an other tty device.
+	 */
+	mask_signal(SIGQUIT, SIG_IGN, &saved_sigquit);
+	mask_signal(SIGTSTP, SIG_IGN, &saved_sigtstp);
+	mask_signal(SIGINT,  SIG_IGN, &saved_sigint);
+	if (optind < argc)
+		tty = argv[optind];
+
+	if (tty || (tty = getenv("CONSOLE"))) {
+
+		if ((fd = open(tty, O_RDWR)) < 0) {
+			warn(_("cannot open %s"), tty);
+			fd = dup(0);
+		}
+
+		if (!isatty(fd)) {
+			warn(_("%s: not a tty"), tty);
+			close(fd);
+		} else {
+
+			/*
+			 * Only go through this trouble if the new tty doesn't
+			 * fall in this process group.
+			 */
+			pid = getpid();
+			pgrp = getpgid(0);
+			ppgrp = getpgid(getppid());
+			ttypgrp = tcgetpgrp(fd);
+
+			if (pgrp != ttypgrp && ppgrp != ttypgrp) {
+				if (pid != getsid(0)) {
+					if (pid == getpgid(0))
+						setpgid(0, getpgid(getppid()));
+					setsid();
+				}
+
+				sigaction(SIGHUP, NULL, &saved_sighup);
+				if (ttypgrp > 0)
+					ioctl(0, TIOCNOTTY, (char *)1);
+				sigaction(SIGHUP, &saved_sighup, NULL);
+				close(0);
+				close(1);
+				close(2);
+				if (fd > 2)
+					close(fd);
+				if ((fd = open(tty, O_RDWR|O_NOCTTY)) < 0)
+					warn(_("cannot open %s"), tty);
+				else {
+					ioctl(0, TIOCSCTTY, (char *)1);
+					tcsetpgrp(fd, ppgrp);
+					dup2(fd, 0);
+					dup2(fd, 1);
+					dup2(fd, 2);
+					if (fd > 2)
+						close(fd);
+				}
+			} else
+				if (fd > 2)
+					close(fd);
+		}
+	} else if (getpid() == 1) {
+		/* We are init. We hence need to set a session anyway */
+		setsid();
+		if (ioctl(0, TIOCSCTTY, (char *)1))
+			warn(_("TIOCSCTTY: ioctl failed"));
+	}
+
+	fixtty();
+
+	/*
+	 * Get the root password.
+	 */
+	if ((pwd = getrootpwent(opt_e)) == NULL) {
+		warnx(_("cannot open password database."));
+		sleep(2);
+	}
+
+	/*
+	 * Ask for the password.
+	 */
+	while (pwd) {
+		if ((p = getpasswd(pwd->pw_passwd)) == NULL)
+			break;
+		if (pwd->pw_passwd[0] == 0 ||
+		    strcmp(crypt(p, pwd->pw_passwd), pwd->pw_passwd) == 0)
+			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, _("Login incorrect\n\n"));
+	}
+
+	/*
+	 * User pressed Control-D.
+	 */
+	return EXIT_SUCCESS;
+}