remove now-unneeded memset

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

diff --git a/loginutils/sulogin.c b/loginutils/sulogin.c
index 8cfb64e9ac1c93dd9e49fe0b53d8e060dd26f302..6e3d3b0190922c08ca11c6a366f450246a540e7b 100644 (file)
--- a/loginutils/sulogin.c
+++ b/loginutils/sulogin.c
@@ -5,86 +5,76 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
+#include "libbb.h"
 #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);
-}
+//static void catchalarm(int UNUSED_PARAM junk)
+//{
+//     exit(EXIT_FAILURE);
+//}
 
 
-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;
-       struct spwd *spwd;
+       const char *shell;
+#if ENABLE_FEATURE_SHADOWPASSWDS
+       /* Using _r function to avoid pulling in static buffers */
+       char buffer[256];
+       struct spwd spw;
+#endif
 
        logmode = LOGMODE_BOTH;
-       openlog(bb_applet_name, 0, LOG_AUTH);
+       openlog(applet_name, 0, LOG_AUTH);
 
-       if (bb_getopt_ulflags (argc, argv, "t:", &timeout_arg)) {
-               if (safe_strtoi(timeout_arg, &timeout)) {
-                       timeout = 0;
-               }
-       }
+       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);
+       /* Clear dangerous stuff, set PATH */
+       sanitize_env_if_suid();
 
-       signal(SIGALRM, catchalarm);
-
-       if (!(pwd = getpwuid(0))) {
+       pwd = getpwuid(0);
+       if (!pwd) {
                goto auth_error;
        }
 
-       if (ENABLE_FEATURE_SHADOWPASSWDS) {
-               if (!(spwd = getspnam(pwd->pw_name))) {
+#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 = spwd->sp_pwdp;
+               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_askpass(timeout,
+               cp = bb_ask(STDIN_FILENO, timeout,
                                "Give root password for system maintenance\n"
                                "(or type Control-D for normal startup):");
 
@@ -92,22 +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());
 
-       run_shell(pwd->pw_shell, 1, 0, 0);
-       /* never returns */
+       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);
 
-auth_error:
-       bb_error_msg_and_die("no password entry for `root'");
+ auth_error:
+       bb_error_msg_and_die("no password entry for root");
 }