tls: prepare for ECDH_anon ciphers

[oweals/busybox.git] / loginutils / sulogin.c

diff --git a/loginutils/sulogin.c b/loginutils/sulogin.c
index 4ffefe933b3a31decd6c2bf5c447b9afa5269960..27ea5dff028b62a18b7adb46b8c04dff34f359b0 100644 (file)
--- a/loginutils/sulogin.c
+++ b/loginutils/sulogin.c
@@ -2,36 +2,48 @@
 /*
  * 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.
  */
+//config:config SULOGIN
+//config:      bool "sulogin (17 kb)"
+//config:      default y
+//config:      select FEATURE_SYSLOG
+//config:      help
+//config:      sulogin is invoked when the system goes into single user
+//config:      mode (this is done through an entry in inittab).
 
-#include "libbb.h"
-#include <syslog.h>
+//applet:IF_SULOGIN(APPLET_NOEXEC(sulogin, sulogin, BB_DIR_SBIN, BB_SUID_DROP, sulogin))
+
+//kbuild:lib-$(CONFIG_SULOGIN) += sulogin.o
 
-//static void catchalarm(int UNUSED_PARAM junk)
-//{
-//     exit(EXIT_FAILURE);
-//}
+//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>
 
 int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int sulogin_main(int argc UNUSED_PARAM, char **argv)
 {
-       char *cp;
        int timeout = 0;
        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;
-#endif
+
+       /* Note: sulogin is not a suid app. It is meant to be run by init
+        * for single user / emergency mode. init starts it as root.
+        * Normal users (potentially malicious ones) can only run it under
+        * their UID, therefore no paranoia here is warranted:
+        * $LD_LIBRARY_PATH in env, TTY = /dev/sda
+        * are no more dangerous here than in e.g. cp applet.
+        */
 
        logmode = LOGMODE_BOTH;
        openlog(applet_name, 0, LOG_AUTH);
 
-       opt_complementary = "t+"; /* -t N */
-       getopt32(argv, "t:", &timeout);
+       getopt32(argv, "t:+", &timeout);
        argv += optind;
 
        if (argv[0]) {
@@ -42,76 +54,40 @@ int sulogin_main(int argc UNUSED_PARAM, char **argv)
                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 dangerous stuff, set PATH */
-       sanitize_env_if_suid();
-
-// bb_ask() already handles this
-//     signal(SIGALRM, catchalarm);
-
        pwd = getpwuid(0);
        if (!pwd) {
-               goto auth_error;
+               bb_error_msg_and_die("no password entry for root");
        }
 
-#if ENABLE_FEATURE_SHADOWPASSWDS
-       {
-               /* 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;
-       }
-#endif
-
        while (1) {
-               char *encrypted;
                int r;
 
-               /* cp points to a static buffer that is zeroed every time */
-               cp = bb_ask(STDIN_FILENO, timeout,
-                               "Give root password for system maintenance\n"
-                               "(or type Control-D for normal startup):");
-
-               if (!cp || !*cp) {
-                       bb_info_msg("Normal startup");
+               r = ask_and_check_password_extended(pwd, timeout,
+                       "Give root password for system maintenance\n"
+                       "(or type Control-D for normal startup):"
+               );
+               if (r < 0) {
+                       /* ^D, ^C, timeout, or read error */
+                       bb_error_msg("normal startup");
                        return 0;
                }
-               encrypted = pw_encrypt(cp, pwd->pw_passwd, 1);
-               r = strcmp(encrypted, pwd->pw_passwd);
-               free(encrypted);
-               if (r == 0) {
+               if (r > 0) {
                        break;
                }
-               bb_do_delay(FAIL_DELAY);
-               bb_error_msg("login incorrect");
+               bb_do_delay(LOGIN_FAIL_DELAY);
+               bb_error_msg("Login incorrect");
        }
-       memset(cp, 0, strlen(cp));
-//     signal(SIGALRM, SIG_DFL);
 
-       bb_info_msg("System Maintenance Mode");
+       bb_error_msg("starting shell for system maintenance");
 
-       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;
-       }
-       /* Exec login shell with no additional parameters. Never returns. */
-       run_shell(shell, 1, NULL, NULL);
+       if (!shell)
+               shell = pwd->pw_shell;
 
- auth_error:
-       bb_error_msg_and_die("no password entry for root");
+       /* Exec login shell with no additional parameters. Never returns. */
+       run_shell(shell, 1, NULL);
 }