1 files changed, 121 insertions, 0 deletions
diff --git a/loginutils/sulogin.c b/loginutils/sulogin.c
new file mode 100644
index 000000000..c07264e7b
--- /dev/null
+++ b/loginutils/sulogin.c
@@ -0,0 +1,121 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini sulogin implementation for busybox
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include <syslog.h>
+
+#include "busybox.h"
+
+static const char * const forbid[] = {
+	"ENV",
+	"BASH_ENV",
+	"HOME",
+	"IFS",
+	"PATH",
+	"SHELL",
+	"LD_LIBRARY_PATH",
+	"LD_PRELOAD",
+	"LD_TRACE_LOADED_OBJECTS",
+	"LD_BIND_NOW",
+	"LD_AOUT_LIBRARY_PATH",
+	"LD_AOUT_PRELOAD",
+	"LD_NOWARN",
+	"LD_KEEPDIR",
+	(char *) 0
+};
+
+
+static void catchalarm(int ATTRIBUTE_UNUSED junk)
+{
+	exit(EXIT_FAILURE);
+}
+
+
+int sulogin_main(int argc, char **argv)
+{
+	char *cp;
+	int timeout = 0;
+	char *timeout_arg;
+	const char * const *p;
+	struct passwd *pwd;
+	struct spwd *spwd;
+	const char *shell;
+
+	logmode = LOGMODE_BOTH;
+	openlog(applet_name, 0, LOG_AUTH);
+
+	if (getopt32(argc, argv, "t:", &timeout_arg)) {
+		timeout = xatoi_u(timeout_arg);
+	}
+
+	if (argv[optind]) {
+		close(0);
+		close(1);
+		dup(xopen(argv[optind], O_RDWR));
+		close(2);
+		dup(0);
+	}
+
+	if (!isatty(0) || !isatty(1) || !isatty(2)) {
+		logmode = LOGMODE_SYSLOG;
+		bb_error_msg_and_die("not a tty");
+	}
+
+	/* Clear out anything dangerous from the environment */
+	for (p = forbid; *p; p++)
+		unsetenv(*p);
+
+	signal(SIGALRM, catchalarm);
+
+	pwd = getpwuid(0);
+	if (!pwd) {
+		goto auth_error;
+	}
+
+	if (ENABLE_FEATURE_SHADOWPASSWDS) {
+		spwd = getspnam(pwd->pw_name);
+		if (!spwd) {
+			goto auth_error;
+		}
+		pwd->pw_passwd = spwd->sp_pwdp;
+	}
+
+	while (1) {
+		/* cp points to a static buffer that is zeroed every time */
+		cp = bb_askpass(timeout,
+				"Give root password for system maintenance\n"
+				"(or type Control-D for normal startup):");
+
+		if (!cp || !*cp) {
+			bb_info_msg("Normal startup");
+			return 0;
+		}
+		if (strcmp(pw_encrypt(cp, pwd->pw_passwd), pwd->pw_passwd) == 0) {
+			break;
+		}
+		bb_do_delay(FAIL_DELAY);
+		bb_error_msg("login incorrect");
+	}
+	memset(cp, 0, strlen(cp));
+	signal(SIGALRM, SIG_DFL);
+
+	bb_info_msg("System Maintenance Mode");
+
+	USE_SELINUX(renew_current_security_context());
+
+	shell = getenv("SUSHELL");
+	if (!shell) shell = getenv("sushell");
+	if (!shell) {
+		shell = "/bin/sh";
+		if (pwd->pw_shell[0])
+			shell = pwd->pw_shell;
+	}
+	run_shell(shell, 1, 0, 0);
+	/* never returns */
+
+auth_error:
+	bb_error_msg_and_die("no password entry for 'root'");
+}