mdev: do not follow symlinks in /sys (as was intended prior to rev 18811).

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

diff --git a/loginutils/login.c b/loginutils/login.c
index 55cbfa7cdb40ecf5c6cc2292c15ebc63ac66ab73..9c7941e0dbc335268b11a8b46366163e611e1267 100644 (file)
--- a/loginutils/login.c
+++ b/loginutils/login.c
@@ -80,7 +80,7 @@ static void read_or_build_utent(struct utmp *utptr, int picky)
                 * remotely meaningful by skipping "tty"... */
                strncpy(utptr->ut_id, short_tty + 3, sizeof(utptr->ut_id));
                strncpy(utptr->ut_user, "LOGIN", sizeof(utptr->ut_user));
-               utptr->ut_time = time(NULL);
+               utptr->ut_tv.tv_sec = time(NULL);
        }
        if (!picky)     /* root login */
                memset(utptr->ut_host, 0, sizeof(utptr->ut_host));
@@ -96,7 +96,7 @@ static void write_utent(struct utmp *utptr, const char *username)
 {
        utptr->ut_type = USER_PROCESS;
        strncpy(utptr->ut_user, username, sizeof(utptr->ut_user));
-       utptr->ut_time = time(NULL);
+       utptr->ut_tv.tv_sec = time(NULL);
        /* other fields already filled in by read_or_build_utent above */
        setutent();
        pututline(utptr);
@@ -114,7 +114,7 @@ static void write_utent(struct utmp *utptr, const char *username)
 #endif /* !ENABLE_FEATURE_UTMP */
 
 #if ENABLE_FEATURE_NOLOGIN
-static void die_if_nologin_and_non_root(int amroot)
+static void die_if_nologin(void)
 {
        FILE *fp;
        int c;
@@ -130,12 +130,10 @@ static void die_if_nologin_and_non_root(int amroot)
                fclose(fp);
        } else
                puts("\r\nSystem closed for routine maintenance\r");
-       if (!amroot)
-               exit(1);
-       puts("\r\n[Disconnect bypassed -- root login allowed]\r");
+       exit(EXIT_FAILURE);
 }
 #else
-static ALWAYS_INLINE void die_if_nologin_and_non_root(int amroot) {}
+static ALWAYS_INLINE void die_if_nologin(void) {}
 #endif
 
 #if ENABLE_FEATURE_SECURETTY && !ENABLE_PAM
@@ -180,18 +178,18 @@ static void get_username_or_die(char *buf, int size_buf)
        /* skip whitespace */
        do {
                c = getchar();
-               if (c == EOF) exit(1);
+               if (c == EOF) exit(EXIT_FAILURE);
                if (c == '\n') {
-                       if (!--cntdown) exit(1);
+                       if (!--cntdown) exit(EXIT_FAILURE);
                        goto prompt;
                }
        } while (isspace(c));
 
        *buf++ = c;
        if (!fgets(buf, size_buf-2, stdin))
-               exit(1);
+               exit(EXIT_FAILURE);
        if (!strchr(buf, '\n'))
-               exit(1);
+               exit(EXIT_FAILURE);
        while (isgraph(*buf)) buf++;
        *buf = '\0';
 }
@@ -208,23 +206,22 @@ static void motd(void)
        }
 }
 
-static void alarm_handler(int sig ATTRIBUTE_UNUSED)
+static void alarm_handler(int sig UNUSED_PARAM)
 {
        /* This is the escape hatch!  Poor serial line users and the like
         * arrive here when their connection is broken.
         * We don't want to block here */
        ndelay_on(1);
-       ndelay_on(2);
        printf("\r\nLogin timed out after %d seconds\r\n", TIMEOUT);
+       fflush(stdout);
        /* unix API is brain damaged regarding O_NONBLOCK,
         * we should undo it, or else we can affect other processes */
        ndelay_off(1);
-       ndelay_off(2);
-       exit(EXIT_SUCCESS);
+       _exit(EXIT_SUCCESS);
 }
 
 int login_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int login_main(int argc, char **argv)
+int login_main(int argc UNUSED_PARAM, char **argv)
 {
        enum {
                LOGIN_OPT_f = (1<<0),
@@ -238,8 +235,8 @@ int login_main(int argc, char **argv)
        unsigned opt;
        int count = 0;
        struct passwd *pw;
-       char *opt_host = NULL;
-       char *opt_user = NULL;
+       char *opt_host = opt_host; /* for compiler */
+       char *opt_user = opt_user; /* for compiler */
        char full_tty[TTYNAME_SIZE];
        USE_SELINUX(security_context_t user_sid = NULL;)
        USE_FEATURE_UTMP(struct utmp utent;)
@@ -254,20 +251,17 @@ int login_main(int argc, char **argv)
 
        short_tty = full_tty;
        username[0] = '\0';
-       amroot = (getuid() == 0);
        signal(SIGALRM, alarm_handler);
        alarm(TIMEOUT);
 
+       /* More of suid paranoia if called by non-root */
+       amroot = !sanitize_env_if_suid(); /* Clear dangerous stuff, set PATH */
+
        /* Mandatory paranoia for suid applet:
         * ensure that fd# 0,1,2 are opened (at least to /dev/null)
         * and any extra open fd's are closed.
         * (The name of the function is misleading. Not daemonizing here.) */
        bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE | DAEMON_CLOSE_EXTRA_FDS, NULL);
-       /* More of suid paranoia if called by non-root */
-       if (!amroot) {
-               /* Clear dangerous stuff, set PATH */
-               sanitize_env_for_suid();
-       }
 
        opt = getopt32(argv, "f:h:p", &opt_user, &opt_host);
        if (opt & LOGIN_OPT_f) {
@@ -275,8 +269,9 @@ int login_main(int argc, char **argv)
                        bb_error_msg_and_die("-f is for root only");
                safe_strncpy(username, opt_user, sizeof(username));
        }
-       if (optind < argc) /* user from command line (getty) */
-               safe_strncpy(username, argv[optind], sizeof(username));
+       argv += optind;
+       if (argv[0]) /* user from command line (getty) */
+               safe_strncpy(username, argv[0], sizeof(username));
 
        /* Let's find out and memorize our tty */
        if (!isatty(0) || !isatty(1) || !isatty(2))
@@ -291,7 +286,7 @@ int login_main(int argc, char **argv)
 
        read_or_build_utent(&utent, !amroot);
 
-       if (opt_host) {
+       if (opt & LOGIN_OPT_h) {
                USE_FEATURE_UTMP(
                        safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
                )
@@ -410,7 +405,8 @@ int login_main(int argc, char **argv)
        }
 
        alarm(0);
-       die_if_nologin_and_non_root(pw->pw_uid == 0);
+       if (!amroot)
+               die_if_nologin();
 
        write_utent(&utent, username);
 
@@ -454,9 +450,12 @@ int login_main(int argc, char **argv)
                        xsetenv("LOGIN_UID", utoa(pw->pw_uid));
                        xsetenv("LOGIN_GID", utoa(pw->pw_gid));
                        xsetenv("LOGIN_SHELL", pw->pw_shell);
-                       xspawn(t_argv); /* NOMMU-friendly */
-                       /* All variables are unset by setup_environment */
-                       wait(NULL);
+                       spawn_and_wait(t_argv); /* NOMMU-friendly */
+                       unsetenv("LOGIN_TTY"  );
+                       unsetenv("LOGIN_USER" );
+                       unsetenv("LOGIN_UID"  );
+                       unsetenv("LOGIN_GID"  );
+                       unsetenv("LOGIN_SHELL");
                }
        }
 
@@ -464,9 +463,8 @@ int login_main(int argc, char **argv)
        tmp = pw->pw_shell;
        if (!tmp || !*tmp)
                tmp = DEFAULT_SHELL;
-       /* setup_environment params: shell, loginshell, changeenv, pw */
-       setup_environment(tmp, 1, !(opt & LOGIN_OPT_p), pw);
-       /* FIXME: login shell = 1 -> 3rd parameter is ignored! */
+       /* setup_environment params: shell, clear_env, change_env, pw */
+       setup_environment(tmp, !(opt & LOGIN_OPT_p), 1, pw);
 
        motd();