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Diffstat (limited to 'i/pc104/initrd/conf/busybox/loginutils/login.c')
-rw-r--r--i/pc104/initrd/conf/busybox/loginutils/login.c403
1 files changed, 403 insertions, 0 deletions
diff --git a/i/pc104/initrd/conf/busybox/loginutils/login.c b/i/pc104/initrd/conf/busybox/loginutils/login.c
new file mode 100644
index 0000000..830df0a
--- /dev/null
+++ b/i/pc104/initrd/conf/busybox/loginutils/login.c
@@ -0,0 +1,403 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include "busybox.h"
+#include <utmp.h>
+#include <sys/resource.h>
+#include <syslog.h>
+
+#ifdef CONFIG_SELINUX
+#include <selinux/selinux.h> /* for is_selinux_enabled() */
+#include <selinux/get_context_list.h> /* for get_default_context() */
+#include <selinux/flask.h> /* for security class definitions */
+#include <errno.h>
+#endif
+
+enum {
+ TIMEOUT = 60,
+ EMPTY_USERNAME_COUNT = 10,
+ USERNAME_SIZE = 32,
+ TTYNAME_SIZE = 32,
+};
+
+static char full_tty[TTYNAME_SIZE];
+static char* short_tty = full_tty;
+
+#if ENABLE_FEATURE_UTMP
+/* vv Taken from tinylogin utmp.c vv */
+/*
+ * read_or_build_utent - see if utmp file is correct for this process
+ *
+ * System V is very picky about the contents of the utmp file
+ * and requires that a slot for the current process exist.
+ * The utmp file is scanned for an entry with the same process
+ * ID. If no entry exists the process exits with a message.
+ *
+ * The "picky" flag is for network and other logins that may
+ * use special flags. It allows the pid checks to be overridden.
+ * This means that getty should never invoke login with any
+ * command line flags.
+ */
+
+static struct utmp utent;
+
+static void read_or_build_utent(int picky)
+{
+ struct utmp *ut;
+ pid_t pid = getpid();
+
+ setutent();
+
+ /* First, try to find a valid utmp entry for this process. */
+ while ((ut = getutent()))
+ if (ut->ut_pid == pid && ut->ut_line[0] && ut->ut_id[0] &&
+ (ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS))
+ break;
+
+ /* If there is one, just use it, otherwise create a new one. */
+ if (ut) {
+ utent = *ut;
+ } else {
+ if (picky)
+ bb_error_msg_and_die("no utmp entry found");
+
+ memset(&utent, 0, sizeof(utent));
+ utent.ut_type = LOGIN_PROCESS;
+ utent.ut_pid = pid;
+ strncpy(utent.ut_line, short_tty, sizeof(utent.ut_line));
+ /* This one is only 4 chars wide. Try to fit something
+ * remotely meaningful by skipping "tty"... */
+ strncpy(utent.ut_id, short_tty + 3, sizeof(utent.ut_id));
+ strncpy(utent.ut_user, "LOGIN", sizeof(utent.ut_user));
+ utent.ut_time = time(NULL);
+ }
+ if (!picky) /* root login */
+ memset(utent.ut_host, 0, sizeof(utent.ut_host));
+}
+
+/*
+ * write_utent - put a USER_PROCESS entry in the utmp file
+ *
+ * write_utent changes the type of the current utmp entry to
+ * USER_PROCESS. the wtmp file will be updated as well.
+ */
+static void write_utent(const char *username)
+{
+ utent.ut_type = USER_PROCESS;
+ strncpy(utent.ut_user, username, sizeof(utent.ut_user));
+ utent.ut_time = time(NULL);
+ /* other fields already filled in by read_or_build_utent above */
+ setutent();
+ pututline(&utent);
+ endutent();
+#if ENABLE_FEATURE_WTMP
+ if (access(bb_path_wtmp_file, R_OK|W_OK) == -1) {
+ close(creat(bb_path_wtmp_file, 0664));
+ }
+ updwtmp(bb_path_wtmp_file, &utent);
+#endif
+}
+#else /* !ENABLE_FEATURE_UTMP */
+static inline void read_or_build_utent(int ATTRIBUTE_UNUSED picky) {}
+static inline void write_utent(const char ATTRIBUTE_UNUSED *username) {}
+#endif /* !ENABLE_FEATURE_UTMP */
+
+static void die_if_nologin_and_non_root(int amroot)
+{
+ FILE *fp;
+ int c;
+
+ if (access(bb_path_nologin_file, F_OK))
+ return;
+
+ fp = fopen(bb_path_nologin_file, "r");
+ if (fp) {
+ while ((c = getc(fp)) != EOF)
+ putchar((c=='\n') ? '\r' : c);
+ fflush(stdout);
+ fclose(fp);
+ } else
+ puts("\r\nSystem closed for routine maintenance\r");
+ if (!amroot)
+ exit(1);
+ puts("\r\n[Disconnect bypassed -- root login allowed.]\r");
+}
+
+#if ENABLE_FEATURE_SECURETTY
+static int check_securetty(void)
+{
+ FILE *fp;
+ int i;
+ char buf[BUFSIZ];
+
+ fp = fopen(bb_path_securetty_file, "r");
+ if (!fp) {
+ /* A missing securetty file is not an error. */
+ return 1;
+ }
+ while (fgets(buf, sizeof(buf)-1, fp)) {
+ for (i = strlen(buf)-1; i>=0; --i) {
+ if (!isspace(buf[i]))
+ break;
+ }
+ buf[++i] = '\0';
+ if ((buf[0]=='\0') || (buf[0]=='#'))
+ continue;
+ if (strcmp(buf, short_tty) == 0) {
+ fclose(fp);
+ return 1;
+ }
+ }
+ fclose(fp);
+ return 0;
+}
+#else
+static inline int check_securetty(void) { return 1; }
+#endif
+
+static void get_username_or_die(char *buf, int size_buf)
+{
+ int c, cntdown;
+ cntdown = EMPTY_USERNAME_COUNT;
+prompt:
+ /* skip whitespace */
+ print_login_prompt();
+ do {
+ c = getchar();
+ if (c == EOF) exit(1);
+ if (c == '\n') {
+ if (!--cntdown) exit(1);
+ goto prompt;
+ }
+ } while (isspace(c));
+
+ *buf++ = c;
+ if (!fgets(buf, size_buf-2, stdin))
+ exit(1);
+ if (!strchr(buf, '\n'))
+ exit(1);
+ while (isgraph(*buf)) buf++;
+ *buf = '\0';
+}
+
+static void motd(void)
+{
+ FILE *fp;
+ int c;
+
+ fp = fopen(bb_path_motd_file, "r");
+ if (fp) {
+ while ((c = getc(fp)) != EOF)
+ putchar(c);
+ fclose(fp);
+ }
+}
+
+static void nonblock(int fd)
+{
+ fcntl(fd, F_SETFL, O_NONBLOCK | fcntl(fd, F_GETFL));
+}
+
+static void alarm_handler(int sig ATTRIBUTE_UNUSED)
+{
+ /* 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 */
+ nonblock(1);
+ nonblock(2);
+ bb_info_msg("\r\nLogin timed out after %d seconds\r", TIMEOUT);
+ exit(EXIT_SUCCESS);
+}
+
+int login_main(int argc, char **argv);
+int login_main(int argc, char **argv)
+{
+ enum {
+ LOGIN_OPT_f = (1<<0),
+ LOGIN_OPT_h = (1<<1),
+ LOGIN_OPT_p = (1<<2),
+ };
+ char fromhost[512];
+ char username[USERNAME_SIZE];
+ const char *tmp;
+ int amroot;
+ unsigned opt;
+ int count = 0;
+ struct passwd *pw;
+ char *opt_host = NULL;
+ char *opt_user = NULL;
+ USE_SELINUX(security_context_t user_sid = NULL;)
+
+ username[0] = '\0';
+ amroot = (getuid() == 0);
+ signal(SIGALRM, alarm_handler);
+ alarm(TIMEOUT);
+
+ opt = getopt32(argc, argv, "f:h:p", &opt_user, &opt_host);
+ if (opt & LOGIN_OPT_f) {
+ if (!amroot)
+ 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));
+
+ /* Let's find out and memorize our tty */
+ if (!isatty(0) || !isatty(1) || !isatty(2))
+ return EXIT_FAILURE; /* Must be a terminal */
+ safe_strncpy(full_tty, "UNKNOWN", sizeof(full_tty));
+ tmp = ttyname(0);
+ if (tmp) {
+ safe_strncpy(full_tty, tmp, sizeof(full_tty));
+ if (strncmp(full_tty, "/dev/", 5) == 0)
+ short_tty = full_tty + 5;
+ }
+
+ read_or_build_utent(!amroot);
+
+ if (opt_host) {
+ USE_FEATURE_UTMP(
+ safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
+ )
+ snprintf(fromhost, sizeof(fromhost)-1, " on '%.100s' from "
+ "'%.200s'", short_tty, opt_host);
+ }
+ else
+ snprintf(fromhost, sizeof(fromhost)-1, " on '%.100s'", short_tty);
+
+ bb_setpgrp;
+
+ openlog(applet_name, LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
+
+ while (1) {
+ if (!username[0])
+ get_username_or_die(username, sizeof(username));
+
+ pw = getpwnam(username);
+ if (!pw) {
+ safe_strncpy(username, "UNKNOWN", sizeof(username));
+ goto auth_failed;
+ }
+
+ if (pw->pw_passwd[0] == '!' || pw->pw_passwd[0] == '*')
+ goto auth_failed;
+
+ if (opt & LOGIN_OPT_f)
+ break; /* -f USER: success without asking passwd */
+
+ if (pw->pw_uid == 0 && !check_securetty())
+ goto auth_failed;
+
+ /* Don't check the password if password entry is empty (!) */
+ if (!pw->pw_passwd[0])
+ break;
+
+ /* authorization takes place here */
+ if (correct_password(pw))
+ break;
+
+auth_failed:
+ opt &= ~LOGIN_OPT_f;
+ bb_do_delay(FAIL_DELAY);
+ puts("Login incorrect");
+ if (++count == 3) {
+ syslog(LOG_WARNING, "invalid password for '%s'%s",
+ username, fromhost);
+ return EXIT_FAILURE;
+ }
+ username[0] = '\0';
+ }
+
+ alarm(0);
+ die_if_nologin_and_non_root(pw->pw_uid == 0);
+
+ write_utent(username);
+
+#ifdef CONFIG_SELINUX
+ if (is_selinux_enabled()) {
+ security_context_t old_tty_sid, new_tty_sid;
+
+ if (get_default_context(username, NULL, &user_sid)) {
+ bb_error_msg_and_die("cannot get SID for %s",
+ username);
+ }
+ if (getfilecon(full_tty, &old_tty_sid) < 0) {
+ bb_perror_msg_and_die("getfilecon(%s) failed",
+ full_tty);
+ }
+ if (security_compute_relabel(user_sid, old_tty_sid,
+ SECCLASS_CHR_FILE, &new_tty_sid) != 0) {
+ bb_perror_msg_and_die("security_change_sid(%s) failed",
+ full_tty);
+ }
+ if (setfilecon(full_tty, new_tty_sid) != 0) {
+ bb_perror_msg_and_die("chsid(%s, %s) failed",
+ full_tty, new_tty_sid);
+ }
+ }
+#endif
+ /* Try these, but don't complain if they fail.
+ * _f_chown is safe wrt race t=ttyname(0);...;chown(t); */
+ fchown(0, pw->pw_uid, pw->pw_gid);
+ fchmod(0, 0600);
+
+ /* TODO: be nommu-friendly, use spawn? */
+ if (ENABLE_LOGIN_SCRIPTS) {
+ char *script = getenv("LOGIN_PRE_SUID_SCRIPT");
+ if (script) {
+ char *t_argv[2] = { script, NULL };
+ switch (fork()) {
+ case -1: break;
+ case 0: /* child */
+ xchdir("/");
+ setenv("LOGIN_TTY", full_tty, 1);
+ setenv("LOGIN_USER", pw->pw_name, 1);
+ setenv("LOGIN_UID", utoa(pw->pw_uid), 1);
+ setenv("LOGIN_GID", utoa(pw->pw_gid), 1);
+ setenv("LOGIN_SHELL", pw->pw_shell, 1);
+ BB_EXECVP(script, t_argv);
+ exit(1);
+ default: /* parent */
+ wait(NULL);
+ }
+ }
+ }
+
+ change_identity(pw);
+ tmp = pw->pw_shell;
+ if (!tmp || !*tmp)
+ tmp = DEFAULT_SHELL;
+ setup_environment(tmp, 1, !(opt & LOGIN_OPT_p), pw);
+
+ motd();
+
+ if (pw->pw_uid == 0)
+ syslog(LOG_INFO, "root login%s", fromhost);
+#ifdef CONFIG_SELINUX
+ /* well, a simple setexeccon() here would do the job as well,
+ * but let's play the game for now */
+ set_current_security_context(user_sid);
+#endif
+
+ // util-linux login also does:
+ // /* start new session */
+ // setsid();
+ // /* TIOCSCTTY: steal tty from other process group */
+ // if (ioctl(0, TIOCSCTTY, 1)) error_msg...
+
+ /* set signals to defaults */
+ signal(SIGALRM, SIG_DFL);
+ /* Is this correct? This way user can ctrl-c out of /etc/profile,
+ * potentially creating security breach (tested with bash 3.0).
+ * But without this, bash 3.0 will not enable ctrl-c either.
+ * Maybe bash is buggy?
+ * Need to find out what standards say about /bin/login -
+ * should it leave SIGINT etc enabled or disabled? */
+ signal(SIGINT, SIG_DFL);
+
+ run_shell(tmp, 1, 0, 0); /* exec the shell finally */
+
+ return EXIT_FAILURE;
+}