/*
* Mini sulogin implementation for busybox
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
-#include <syslog.h>
+//usage:#define sulogin_trivial_usage
+//usage: "[-t N] [TTY]"
+//usage:#define sulogin_full_usage "\n\n"
+//usage: "Single user login\n"
+//usage: "\n -t N Timeout"
#include "libbb.h"
+#include <syslog.h>
-static const char forbid[] ALIGN1 =
- "ENV" "\0"
- "BASH_ENV" "\0"
- "HOME" "\0"
- "IFS" "\0"
- "PATH" "\0"
- "SHELL" "\0"
- "LD_LIBRARY_PATH" "\0"
- "LD_PRELOAD" "\0"
- "LD_TRACE_LOADED_OBJECTS" "\0"
- "LD_BIND_NOW" "\0"
- "LD_AOUT_LIBRARY_PATH" "\0"
- "LD_AOUT_PRELOAD" "\0"
- "LD_NOWARN" "\0"
- "LD_KEEPDIR" "\0";
-
-//static void catchalarm(int ATTRIBUTE_UNUSED junk)
+//static void catchalarm(int UNUSED_PARAM junk)
//{
// exit(EXIT_FAILURE);
//}
int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int sulogin_main(int argc, char **argv)
+int sulogin_main(int argc UNUSED_PARAM, char **argv)
{
char *cp;
int timeout = 0;
- char *timeout_arg;
- const char *p;
struct passwd *pwd;
const char *shell;
#if ENABLE_FEATURE_SHADOWPASSWDS
/* Using _r function to avoid pulling in static buffers */
char buffer[256];
struct spwd spw;
- struct spwd *result;
#endif
logmode = LOGMODE_BOTH;
openlog(applet_name, 0, LOG_AUTH);
- if (getopt32(argv, "t:", &timeout_arg)) {
- timeout = xatoi_u(timeout_arg);
- }
+ opt_complementary = "t+"; /* -t N */
+ getopt32(argv, "t:", &timeout);
+ argv += optind;
- if (argv[optind]) {
+ if (argv[0]) {
close(0);
close(1);
- dup(xopen(argv[optind], O_RDWR));
+ dup(xopen(argv[0], O_RDWR));
close(2);
dup(0);
}
+ /* Malicious use like "sulogin /dev/sda"? */
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 */
- p = forbid;
- do {
- unsetenv(p);
- p += strlen(p) + 1;
- } while (*p);
-
-// bb_askpass() already handles this
-// signal(SIGALRM, catchalarm);
+ /* Clear dangerous stuff, set PATH */
+ sanitize_env_if_suid();
pwd = getpwuid(0);
if (!pwd) {
}
#if ENABLE_FEATURE_SHADOWPASSWDS
- if (getspnam_r(pwd->pw_name, &spw, buffer, sizeof(buffer), &result)) {
- goto auth_error;
+ {
+ /* getspnam_r may return 0 yet set result to NULL.
+ * At least glibc 2.4 does this. Be extra paranoid here. */
+ struct spwd *result = NULL;
+ int r = getspnam_r(pwd->pw_name, &spw, buffer, sizeof(buffer), &result);
+ if (r || !result) {
+ goto auth_error;
+ }
+ pwd->pw_passwd = result->sp_pwdp;
}
- pwd->pw_passwd = spw.sp_pwdp;
#endif
while (1) {
+ char *encrypted;
+ int r;
+
/* cp points to a static buffer that is zeroed every time */
- cp = bb_askpass(timeout,
+ cp = bb_ask(STDIN_FILENO, timeout,
"Give root password for system maintenance\n"
"(or type Control-D for normal startup):");
bb_info_msg("Normal startup");
return 0;
}
- if (strcmp(pw_encrypt(cp, pwd->pw_passwd), pwd->pw_passwd) == 0) {
+ encrypted = pw_encrypt(cp, pwd->pw_passwd, 1);
+ r = strcmp(encrypted, pwd->pw_passwd);
+ free(encrypted);
+ if (r == 0) {
break;
}
- bb_do_delay(FAIL_DELAY);
- bb_error_msg("login incorrect");
+ bb_do_delay(LOGIN_FAIL_DELAY);
+ bb_info_msg("Login incorrect");
}
memset(cp, 0, strlen(cp));
// signal(SIGALRM, SIG_DFL);
bb_info_msg("System Maintenance Mode");
- USE_SELINUX(renew_current_security_context());
+ IF_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;
- }
+ if (!shell)
+ shell = pwd->pw_shell;
+
/* Exec login shell with no additional parameters. Never returns. */
run_shell(shell, 1, NULL, NULL);