//usage: "[-p] [-h HOST] [[-f] USER]"
//usage:#define login_full_usage "\n\n"
//usage: "Begin a new session on the system\n"
-//usage: "\nOptions:"
//usage: "\n -f Don't authenticate (user already authenticated)"
//usage: "\n -h Name of the remote host"
//usage: "\n -p Preserve environment"
enum {
TIMEOUT = 60,
EMPTY_USERNAME_COUNT = 10,
- USERNAME_SIZE = 32,
+ /* Some users found 32 chars limit to be too low: */
+ USERNAME_SIZE = 64,
TTYNAME_SIZE = 32,
};
-static char* short_tty;
+struct globals {
+ struct termios tty_attrs;
+} FIX_ALIASING;
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define INIT_G() do { } while (0)
+
#if ENABLE_FEATURE_NOLOGIN
static void die_if_nologin(void)
#endif
#if ENABLE_FEATURE_SECURETTY && !ENABLE_PAM
-static int check_securetty(void)
+static int check_securetty(const char *short_tty)
{
char *buf = (char*)"/etc/securetty"; /* any non-NULL is ok */
parser_t *parser = config_open2("/etc/securetty", fopen_for_read);
return buf != NULL;
}
#else
-static ALWAYS_INLINE int check_securetty(void) { return 1; }
+static ALWAYS_INLINE int check_securetty(const char *short_tty UNUSED_PARAM) { return 1; }
#endif
#if ENABLE_SELINUX
void run_login_script(struct passwd *pw, char *full_tty);
#endif
+#if ENABLE_LOGIN_SESSION_AS_CHILD && ENABLE_PAM
+static void login_pam_end(pam_handle_t *pamh)
+{
+ int pamret;
+
+ pamret = pam_setcred(pamh, PAM_DELETE_CRED);
+ if (pamret != PAM_SUCCESS) {
+ bb_error_msg("pam_%s failed: %s (%d)", "setcred",
+ pam_strerror(pamh, pamret), pamret);
+ }
+ pamret = pam_close_session(pamh, 0);
+ if (pamret != PAM_SUCCESS) {
+ bb_error_msg("pam_%s failed: %s (%d)", "close_session",
+ pam_strerror(pamh, pamret), pamret);
+ }
+ pamret = pam_end(pamh, pamret);
+ if (pamret != PAM_SUCCESS) {
+ bb_error_msg("pam_%s failed: %s (%d)", "end",
+ pam_strerror(pamh, pamret), pamret);
+ }
+}
+#endif /* ENABLE_PAM */
+
static void get_username_or_die(char *buf, int size_buf)
{
int c, cntdown;
static void alarm_handler(int sig UNUSED_PARAM)
{
- /* This is the escape hatch! Poor serial line users and the like
+ /* 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);
- printf("\r\nLogin timed out after %d seconds\r\n", TIMEOUT);
+ ndelay_on(STDOUT_FILENO);
+ /* Test for correct attr restoring:
+ * run "getty 0 -" from a shell, enter bogus username, stop at
+ * password prompt, let it time out. Without the tcsetattr below,
+ * when you are back at shell prompt, echo will be still off.
+ */
+ tcsetattr_stdin_TCSANOW(&G.tty_attrs);
+ printf("\r\nLogin timed out after %u seconds\r\n", TIMEOUT);
fflush_all();
/* unix API is brain damaged regarding O_NONBLOCK,
* we should undo it, or else we can affect other processes */
- ndelay_off(1);
+ ndelay_off(STDOUT_FILENO);
_exit(EXIT_SUCCESS);
}
char *opt_host = NULL;
char *opt_user = opt_user; /* for compiler */
char *full_tty;
+ char *short_tty;
IF_SELINUX(security_context_t user_sid = NULL;)
#if ENABLE_PAM
int pamret;
char pwdbuf[256];
char **pamenv;
#endif
+#if ENABLE_LOGIN_SESSION_AS_CHILD
+ pid_t child_pid;
+#endif
- username[0] = '\0';
- signal(SIGALRM, alarm_handler);
- alarm(TIMEOUT);
+ INIT_G();
/* More of suid paranoia if called by non-root: */
/* Clear dangerous stuff, set PATH */
* (The name of the function is misleading. Not daemonizing here.) */
bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE | DAEMON_CLOSE_EXTRA_FDS, NULL);
+ username[0] = '\0';
opt = getopt32(argv, "f:h:p", &opt_user, &opt_host);
if (opt & LOGIN_OPT_f) {
if (!run_by_root)
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(STDIN_FILENO) || !isatty(STDOUT_FILENO) || !isatty(STDERR_FILENO))
+ /* Save tty attributes - and by doing it, check that it's indeed a tty */
+ if (tcgetattr(STDIN_FILENO, &G.tty_attrs) < 0
+ || !isatty(STDOUT_FILENO)
+ /*|| !isatty(STDERR_FILENO) - no, guess some people might want to redirect this */
+ ) {
return EXIT_FAILURE; /* Must be a terminal */
+ }
+
+ /* We install timeout handler only _after_ we saved G.tty_attrs */
+ signal(SIGALRM, alarm_handler);
+ alarm(TIMEOUT);
+
+ /* Find out and memorize our tty name */
full_tty = xmalloc_ttyname(STDIN_FILENO);
if (!full_tty)
full_tty = xstrdup("UNKNOWN");
goto pam_auth_failed;
}
}
- pamret = pam_authenticate(pamh, 0);
- if (pamret != PAM_SUCCESS) {
- failed_msg = "authenticate";
- goto pam_auth_failed;
- /* TODO: or just "goto auth_failed"
- * since user seems to enter wrong password
- * (in this case pamret == 7)
- */
+ if (!(opt & LOGIN_OPT_f)) {
+ pamret = pam_authenticate(pamh, 0);
+ if (pamret != PAM_SUCCESS) {
+ failed_msg = "authenticate";
+ goto pam_auth_failed;
+ /* TODO: or just "goto auth_failed"
+ * since user seems to enter wrong password
+ * (in this case pamret == 7)
+ */
+ }
}
/* check that the account is healthy */
pamret = pam_acct_mgmt(pamh, 0);
if (opt & LOGIN_OPT_f)
break; /* -f USER: success without asking passwd */
- if (pw->pw_uid == 0 && !check_securetty())
+ if (pw->pw_uid == 0 && !check_securetty(short_tty))
goto auth_failed;
/* Don't check the password if password entry is empty (!) */
if (!pw->pw_passwd[0])
break;
fake_it:
- /* authorization takes place here */
- if (correct_password(pw))
+ /* Password reading and authorization takes place here.
+ * Note that reads (in no-echo mode) trash tty attributes.
+ * If we get interrupted by SIGALRM, we need to restore attrs.
+ */
+ if (ask_and_check_password(pw) > 0)
break;
#endif /* ENABLE_PAM */
auth_failed:
if (pw->pw_uid != 0)
die_if_nologin();
- IF_SELINUX(initselinux(username, full_tty, &user_sid));
+#if ENABLE_LOGIN_SESSION_AS_CHILD
+ child_pid = vfork();
+ if (child_pid != 0) {
+ if (child_pid < 0)
+ bb_perror_msg("vfork");
+ else {
+ if (safe_waitpid(child_pid, NULL, 0) == -1)
+ bb_perror_msg("waitpid");
+ update_utmp_DEAD_PROCESS(child_pid);
+ }
+ IF_PAM(login_pam_end(pamh);)
+ return 0;
+ }
+#endif
+
+ IF_SELINUX(initselinux(username, full_tty, &user_sid);)
/* Try these, but don't complain if they fail.
* _f_chown is safe wrt race t=ttyname(0);...;chown(t); */
projects / oweals / busybox.git / blobdiff