remove now-unneeded memset

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

diff --git a/loginutils/sulogin.c b/loginutils/sulogin.c
index 5f0a4081d2213c2b447da820664de0b7c3b517a4..6e3d3b0190922c08ca11c6a366f450246a540e7b 100644 (file)
--- a/loginutils/sulogin.c
+++ b/loginutils/sulogin.c
@@ -5,76 +5,51 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <syslog.h>
-
 #include "libbb.h"
+#include <syslog.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);
-}
+//static void catchalarm(int UNUSED_PARAM junk)
+//{
+//     exit(EXIT_FAILURE);
+//}
 
 
-int sulogin_main(int argc, char **argv);
-int sulogin_main(int argc, char **argv)
+int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int sulogin_main(int argc UNUSED_PARAM, char **argv)
 {
        char *cp;
        int timeout = 0;
-       char *timeout_arg;
-       const char *const *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 */
-       for (p = forbid; *p; p++)
-               unsetenv(*p);
-
-       signal(SIGALRM, catchalarm);
+       /* Clear dangerous stuff, set PATH */
+       sanitize_env_if_suid();
 
        pwd = getpwuid(0);
        if (!pwd) {
@@ -82,15 +57,24 @@ int sulogin_main(int argc, char **argv)
        }
 
 #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):");
 
@@ -98,29 +82,33 @@ int sulogin_main(int argc, char **argv)
                        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");
        }
        memset(cp, 0, strlen(cp));
-       signal(SIGALRM, SIG_DFL);
+//     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 = getenv("sushell");
        if (!shell) {
                shell = "/bin/sh";
                if (pwd->pw_shell[0])
                        shell = pwd->pw_shell;
        }
-       run_shell(shell, 1, 0, 0);
-       /* never returns */
+       /* Exec login shell with no additional parameters. Never returns. */
+       run_shell(shell, 1, NULL, NULL);
 
-auth_error:
-       bb_error_msg_and_die("no password entry for 'root'");
+ auth_error:
+       bb_error_msg_and_die("no password entry for root");
 }