/* vi: set sw=4 ts=4: */
-#include <fcntl.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+/*
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
#include <syslog.h>
-#include <termios.h>
-#include <unistd.h>
#include <utmp.h>
#include <sys/resource.h>
-#include <sys/stat.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <ctype.h>
-#include <time.h>
-
-#include "busybox.h"
-#ifdef CONFIG_SELINUX
-#include <flask_util.h>
-#include <get_sid_list.h>
-#include <proc_secure.h>
-#include <fs_secure.h>
-#endif
-#ifdef CONFIG_FEATURE_U_W_TMP
-// import from utmp.c
-static void checkutmp(int picky);
-static void setutmp(const char *name, const char *line);
-/* Stuff global to this file */
-struct utmp utent;
+#if ENABLE_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 */
#endif
-// login defines
-#define TIMEOUT 60
-#define EMPTY_USERNAME_COUNT 10
-#define USERNAME_SIZE 32
+#if ENABLE_PAM
+/* PAM may include <locale.h>. We may need to undefine bbox's stub define: */
+#undef setlocale
+/* For some obscure reason, PAM is not in pam/xxx, but in security/xxx.
+ * Apparently they like to confuse people. */
+#include <security/pam_appl.h>
+#include <security/pam_misc.h>
+static const struct pam_conv conv = {
+ misc_conv,
+ NULL
+};
+#endif
+enum {
+ TIMEOUT = 60,
+ EMPTY_USERNAME_COUNT = 10,
+ USERNAME_SIZE = 32,
+ TTYNAME_SIZE = 32,
+};
-static int check_nologin ( int amroot );
+static char* short_tty;
-#if defined CONFIG_FEATURE_SECURETTY
-static int check_tty ( const char *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.
+ */
-#else
-static inline int check_tty ( const char *tty ) { return 1; }
+static void read_or_build_utent(struct utmp *utptr, int run_by_root)
+{
+ struct utmp *ut;
+ pid_t pid = getpid();
-#endif
+ setutent();
-static int is_my_tty ( const char *tty );
-static int login_prompt ( char *buf_name );
-static void motd ( void );
+ /* First, try to find a valid utmp entry for this process. */
+ /* If there is one, just use it. */
+ while ((ut = getutent()) != NULL)
+ if (ut->ut_pid == pid && ut->ut_line[0] && ut->ut_id[0]
+ && (ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS)
+ ) {
+ *utptr = *ut; /* struct copy */
+ if (run_by_root) /* why only for root? */
+ memset(utptr->ut_host, 0, sizeof(utptr->ut_host));
+ return;
+ }
+// Why? Do we require non-root to exec login from another
+// former login process (e.g. login shell)? Some login's have
+// login shells as children, so it won't work...
+// if (!run_by_root)
+// bb_error_msg_and_die("no utmp entry found");
+
+ /* Otherwise create a new one. */
+ memset(utptr, 0, sizeof(*utptr));
+ utptr->ut_type = LOGIN_PROCESS;
+ utptr->ut_pid = pid;
+ strncpy(utptr->ut_line, short_tty, sizeof(utptr->ut_line));
+ /* This one is only 4 chars wide. Try to fit something
+ * 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_tv.tv_sec = time(NULL);
+}
-static void alarm_handler ( int sig )
+/*
+ * 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(struct utmp *utptr, const char *username)
{
- fprintf (stderr, "\nLogin timed out after %d seconds.\n", TIMEOUT );
- exit ( EXIT_SUCCESS );
+ utptr->ut_type = USER_PROCESS;
+ strncpy(utptr->ut_user, username, sizeof(utptr->ut_user));
+ utptr->ut_tv.tv_sec = time(NULL);
+ /* other fields already filled in by read_or_build_utent above */
+ setutent();
+ pututline(utptr);
+ 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, utptr);
+#endif
}
+#else /* !ENABLE_FEATURE_UTMP */
+#define read_or_build_utent(utptr, run_by_root) ((void)0)
+#define write_utent(utptr, username) ((void)0)
+#endif /* !ENABLE_FEATURE_UTMP */
-
-extern int login_main(int argc, char **argv)
+#if ENABLE_FEATURE_NOLOGIN
+static void die_if_nologin(void)
{
- char tty[BUFSIZ];
- char full_tty[200];
- char fromhost[512];
- char username[USERNAME_SIZE];
- char *tmp;
- int amroot;
- int flag;
- int failed;
- int count=0;
- struct passwd *pw, pw_copy;
-#ifdef CONFIG_WHEEL_GROUP
- struct group *grp;
-#endif
- int opt_preserve = 0;
- int opt_fflag = 0;
- char *opt_host = 0;
- int alarmstarted = 0;
-#ifdef CONFIG_SELINUX
- int flask_enabled = is_flask_enabled();
- security_id_t sid = 0, old_tty_sid, new_tty_sid;
+ FILE *fp;
+ int c;
+ int empty = 1;
+
+ fp = fopen_for_read("/etc/nologin");
+ if (!fp) /* assuming it does not exist */
+ return;
+
+ while ((c = getc(fp)) != EOF) {
+ if (c == '\n')
+ bb_putchar('\r');
+ bb_putchar(c);
+ empty = 0;
+ }
+ if (empty)
+ puts("\r\nSystem closed for routine maintenance\r");
+
+ fclose(fp);
+ fflush_all();
+ /* Users say that they do need this prior to exit: */
+ tcdrain(STDOUT_FILENO);
+ exit(EXIT_FAILURE);
+}
+#else
+static ALWAYS_INLINE void die_if_nologin(void) {}
#endif
- username[0]=0;
- amroot = ( getuid ( ) == 0 );
- signal ( SIGALRM, alarm_handler );
- alarm ( TIMEOUT );
- alarmstarted = 1;
-
- while (( flag = getopt(argc, argv, "f:h:p")) != EOF ) {
- switch ( flag ) {
- case 'p':
- opt_preserve = 1;
- break;
- case 'f':
- /*
- * username must be a seperate token
- * (-f root, *NOT* -froot). --marekm
- */
- if ( optarg != argv[optind-1] )
- bb_show_usage( );
-
- if ( !amroot ) /* Auth bypass only if real UID is zero */
- bb_error_msg_and_die ( "-f permission denied" );
-
- safe_strncpy(username, optarg, USERNAME_SIZE);
- opt_fflag = 1;
- break;
- case 'h':
- opt_host = optarg;
+#if ENABLE_FEATURE_SECURETTY && !ENABLE_PAM
+static int check_securetty(void)
+{
+ char *buf = (char*)"/etc/securetty"; /* any non-NULL is ok */
+ parser_t *parser = config_open2("/etc/securetty", fopen_for_read);
+ while (config_read(parser, &buf, 1, 1, "# \t", PARSE_NORMAL)) {
+ if (strcmp(buf, short_tty) == 0)
break;
- default:
- bb_show_usage( );
- }
+ buf = NULL;
}
-
- if (optind < argc) // user from command line (getty)
- safe_strncpy(username, argv[optind], USERNAME_SIZE);
-
- if ( !isatty ( 0 ) || !isatty ( 1 ) || !isatty ( 2 ))
- return EXIT_FAILURE; /* Must be a terminal */
-
-#ifdef CONFIG_FEATURE_U_W_TMP
- checkutmp ( !amroot );
-#endif
-
- tmp = ttyname ( 0 );
- if ( tmp && ( strncmp ( tmp, "/dev/", 5 ) == 0 ))
- safe_strncpy ( tty, tmp + 5, sizeof( tty ));
- else
- safe_strncpy ( tty, "UNKNOWN", sizeof( tty ));
-
-#ifdef CONFIG_FEATURE_U_W_TMP
- if ( amroot )
- memset ( utent.ut_host, 0, sizeof utent.ut_host );
-#endif
-
- if ( opt_host ) {
-#ifdef CONFIG_FEATURE_U_W_TMP
- safe_strncpy ( utent.ut_host, opt_host, sizeof( utent. ut_host ));
+ config_close(parser);
+ /* buf != NULL here if config file was not found, empty
+ * or line was found which equals short_tty */
+ return buf != NULL;
+}
+#else
+static ALWAYS_INLINE int check_securetty(void) { return 1; }
#endif
- snprintf ( fromhost, sizeof( fromhost ) - 1, " on `%.100s' from `%.200s'", tty, opt_host );
- }
- else
- snprintf ( fromhost, sizeof( fromhost ) - 1, " on `%.100s'", tty );
-
- setpgrp();
-
- openlog ( "login", LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH );
-
- while ( 1 ) {
- failed = 0;
-
- if ( !username[0] )
- if(!login_prompt ( username ))
- return EXIT_FAILURE;
- if ( !alarmstarted && ( TIMEOUT > 0 )) {
- alarm ( TIMEOUT );
- alarmstarted = 1;
- }
-
- if (!( pw = getpwnam ( username ))) {
- pw_copy.pw_name = "UNKNOWN";
- pw_copy.pw_passwd = "!";
- opt_fflag = 0;
- failed = 1;
- } else
- pw_copy = *pw;
-
- pw = &pw_copy;
-
- if (( pw-> pw_passwd [0] == '!' ) || ( pw-> pw_passwd[0] == '*' ))
- failed = 1;
-
- if ( opt_fflag ) {
- opt_fflag = 0;
- goto auth_ok;
- }
-
- if (!failed && ( pw-> pw_uid == 0 ) && ( !check_tty ( tty )))
- failed = 1;
-
- /* Don't check the password if password entry is empty (!) */
- if ( !pw-> pw_passwd[0] )
- goto auth_ok;
-
- /* authorization takes place here */
- if ( correct_password ( pw ))
- goto auth_ok;
-
- failed = 1;
-
-auth_ok:
- if ( !failed)
- break;
+#if ENABLE_SELINUX
+static void initselinux(char *username, char *full_tty,
+ security_context_t *user_sid)
+{
+ security_context_t old_tty_sid, new_tty_sid;
- { // delay next try
- time_t start, now;
-
- time ( &start );
- now = start;
- while ( difftime ( now, start ) < FAIL_DELAY) {
- sleep ( FAIL_DELAY );
- time ( &now );
- }
- }
+ if (!is_selinux_enabled())
+ return;
- puts("Login incorrect");
- username[0] = 0;
- if ( ++count == 3 ) {
- syslog ( LOG_WARNING, "invalid password for `%s'%s\n", pw->pw_name, fromhost);
- return EXIT_FAILURE;
+ if (get_default_context(username, NULL, user_sid)) {
+ bb_error_msg_and_die("can't get SID for %s", username);
}
+ if (getfilecon(full_tty, &old_tty_sid) < 0) {
+ bb_perror_msg_and_die("getfilecon(%s) failed", full_tty);
}
-
- alarm ( 0 );
- if ( check_nologin ( pw-> pw_uid == 0 ))
- return EXIT_FAILURE;
-
-#ifdef CONFIG_FEATURE_U_W_TMP
- setutmp ( username, tty );
-#endif
-#ifdef CONFIG_SELINUX
- if (flask_enabled)
- {
- struct stat st;
-
- if (get_default_sid(username, 0, &sid))
- {
- fprintf(stderr, "Unable to get SID for %s\n", username);
- exit(1);
- }
- if (stat_secure(tty, &st, &old_tty_sid))
- {
- fprintf(stderr, "stat_secure(%.100s) failed: %.100s\n", tty, strerror(errno));
- return EXIT_FAILURE;
- }
- if (security_change_sid (sid, old_tty_sid, SECCLASS_CHR_FILE, &new_tty_sid) != 0)
- {
- fprintf(stderr, "security_change_sid(%.100s) failed: %.100s\n", tty, strerror(errno));
- return EXIT_FAILURE;
- }
- if(chsid(tty, new_tty_sid) != 0)
- {
- fprintf(stderr, "chsid(%.100s, %d) failed: %.100s\n", tty, new_tty_sid, strerror(errno));
- return EXIT_FAILURE;
- }
+ 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);
}
- else
- sid = 0;
-#endif
-
- if ( *tty != '/' )
- snprintf ( full_tty, sizeof( full_tty ) - 1, "/dev/%s", tty);
- else
- safe_strncpy ( full_tty, tty, sizeof( full_tty ) - 1 );
-
- if ( !is_my_tty ( full_tty ))
- syslog ( LOG_ERR, "unable to determine TTY name, got %s\n", full_tty );
-
- /* Try these, but don't complain if they fail
- * (for example when the root fs is read only) */
- chown ( full_tty, pw-> pw_uid, pw-> pw_gid );
- chmod ( full_tty, 0600 );
-
- change_identity ( pw );
- setup_environment ( pw-> pw_shell, 1, !opt_preserve, pw );
-
- motd ( );
- signal ( SIGALRM, SIG_DFL ); /* default alarm signal */
-
- if ( pw-> pw_uid == 0 )
- syslog ( LOG_INFO, "root login %s\n", fromhost );
-
- run_shell ( pw-> pw_shell, 1, 0, 0
-#ifdef CONFIG_SELINUX
- , sid
-#endif
- ); /* exec the shell finally. */
-
- return EXIT_FAILURE;
}
+#endif
-
-
-static int login_prompt ( char *buf_name )
+#if ENABLE_LOGIN_SCRIPTS
+static void run_login_script(struct passwd *pw, char *full_tty)
{
- char buf [1024];
- char *sp, *ep;
- int i;
-
- for(i=0; i<EMPTY_USERNAME_COUNT; i++) {
- print_login_prompt();
-
- if ( !fgets ( buf, sizeof( buf ) - 1, stdin ))
- return 0;
-
- if ( !strchr ( buf, '\n' ))
- return 0;
-
- for ( sp = buf; isspace ( *sp ); sp++ ) { }
- for ( ep = sp; isgraph ( *ep ); ep++ ) { }
-
- *ep = 0;
- safe_strncpy(buf_name, sp, USERNAME_SIZE);
- if(buf_name[0])
- return 1;
+ char *t_argv[2];
+
+ t_argv[0] = getenv("LOGIN_PRE_SUID_SCRIPT");
+ if (t_argv[0]) {
+ t_argv[1] = NULL;
+ xsetenv("LOGIN_TTY", full_tty);
+ xsetenv("LOGIN_USER", pw->pw_name);
+ xsetenv("LOGIN_UID", utoa(pw->pw_uid));
+ xsetenv("LOGIN_GID", utoa(pw->pw_gid));
+ xsetenv("LOGIN_SHELL", pw->pw_shell);
+ spawn_and_wait(t_argv); /* NOMMU-friendly */
+ unsetenv("LOGIN_TTY");
+ unsetenv("LOGIN_USER");
+ unsetenv("LOGIN_UID");
+ unsetenv("LOGIN_GID");
+ unsetenv("LOGIN_SHELL");
}
- return 0;
}
+#else
+void run_login_script(struct passwd *pw, char *full_tty);
+#endif
-
-static int check_nologin ( int amroot )
+static void get_username_or_die(char *buf, int size_buf)
{
- if ( access ( bb_path_nologin_file, F_OK ) == 0 ) {
- FILE *fp;
- int c;
-
- if (( fp = fopen ( bb_path_nologin_file, "r" ))) {
- while (( c = getc ( fp )) != EOF )
- putchar (( c == '\n' ) ? '\r' : c );
-
- fflush ( stdout );
- fclose ( fp );
- } else {
- puts ( "\r\nSystem closed for routine maintenance.\r" );
+ int c, cntdown;
+
+ cntdown = EMPTY_USERNAME_COUNT;
+ prompt:
+ print_login_prompt();
+ /* skip whitespace */
+ do {
+ c = getchar();
+ if (c == EOF)
+ exit(EXIT_FAILURE);
+ if (c == '\n') {
+ if (!--cntdown)
+ exit(EXIT_FAILURE);
+ goto prompt;
}
- if ( !amroot )
- return 1;
-
- puts ( "\r\n[Disconnect bypassed -- root login allowed.]\r" );
- }
- return 0;
+ } while (isspace(c)); /* maybe isblank? */
+
+ *buf++ = c;
+ if (!fgets(buf, size_buf-2, stdin))
+ exit(EXIT_FAILURE);
+ if (!strchr(buf, '\n'))
+ exit(EXIT_FAILURE);
+ while ((unsigned char)*buf > ' ')
+ buf++;
+ *buf = '\0';
}
-#ifdef CONFIG_FEATURE_SECURETTY
-
-static int check_tty ( const char *tty )
+static void motd(void)
{
- FILE *fp;
- int i;
- char buf[BUFSIZ];
-
- if (( fp = fopen ( bb_path_securetty_file, "r" ))) {
- while ( fgets ( buf, sizeof( buf ) - 1, fp )) {
- for ( i = bb_strlen( buf ) - 1; i >= 0; --i ) {
- if ( !isspace ( buf[i] ))
- break;
- }
- buf[++i] = '\0';
- if (( buf [0] == '\0' ) || ( buf [0] == '#' ))
- continue;
-
- if ( strcmp ( buf, tty ) == 0 ) {
- fclose ( fp );
- return 1;
- }
- }
- fclose(fp);
- return 0;
+ int fd;
+
+ fd = open(bb_path_motd_file, O_RDONLY);
+ if (fd >= 0) {
+ fflush_all();
+ bb_copyfd_eof(fd, STDOUT_FILENO);
+ close(fd);
}
- /* A missing securetty file is not an error. */
- return 1;
}
-#endif
-
-/* returns 1 if true */
-static int is_my_tty ( const char *tty )
+static void alarm_handler(int sig UNUSED_PARAM)
{
- struct stat by_name, by_fd;
-
- if ( stat ( tty, &by_name ) || fstat ( 0, &by_fd ))
- return 0;
-
- if ( by_name. st_rdev != by_fd. st_rdev )
- return 0;
- else
- return 1;
+ /* 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);
+ fflush_all();
+ /* unix API is brain damaged regarding O_NONBLOCK,
+ * we should undo it, or else we can affect other processes */
+ ndelay_off(1);
+ _exit(EXIT_SUCCESS);
}
-
-static void motd ( )
+int login_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int login_main(int argc UNUSED_PARAM, char **argv)
{
- FILE *fp;
- register int c;
+ enum {
+ LOGIN_OPT_f = (1<<0),
+ LOGIN_OPT_h = (1<<1),
+ LOGIN_OPT_p = (1<<2),
+ };
+ char *fromhost;
+ char username[USERNAME_SIZE];
+ const char *tmp;
+ int run_by_root;
+ unsigned opt;
+ int count = 0;
+ struct passwd *pw;
+ char *opt_host = opt_host; /* for compiler */
+ char *opt_user = opt_user; /* for compiler */
+ char *full_tty;
+ IF_SELINUX(security_context_t user_sid = NULL;)
+ IF_FEATURE_UTMP(struct utmp utent;)
+#if ENABLE_PAM
+ int pamret;
+ pam_handle_t *pamh;
+ const char *pamuser;
+ const char *failed_msg;
+ struct passwd pwdstruct;
+ char pwdbuf[256];
+#endif
- if (( fp = fopen ( bb_path_motd_file, "r" ))) {
- while (( c = getc ( fp )) != EOF )
- putchar ( c );
- fclose ( fp );
+ username[0] = '\0';
+ signal(SIGALRM, alarm_handler);
+ alarm(TIMEOUT);
+
+ /* More of suid paranoia if called by non-root: */
+ /* Clear dangerous stuff, set PATH */
+ run_by_root = !sanitize_env_if_suid();
+
+ /* 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);
+
+ opt = getopt32(argv, "f:h:p", &opt_user, &opt_host);
+ if (opt & LOGIN_OPT_f) {
+ if (!run_by_root)
+ bb_error_msg_and_die("-f is for root only");
+ safe_strncpy(username, opt_user, 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(STDIN_FILENO) || !isatty(STDOUT_FILENO) || !isatty(STDERR_FILENO))
+ return EXIT_FAILURE; /* Must be a terminal */
+ full_tty = xmalloc_ttyname(STDIN_FILENO);
+ if (!full_tty)
+ full_tty = xstrdup("UNKNOWN");
+ short_tty = full_tty;
+ if (strncmp(full_tty, "/dev/", 5) == 0)
+ short_tty += 5;
+
+ read_or_build_utent(&utent, run_by_root);
+
+ if (opt & LOGIN_OPT_h) {
+ IF_FEATURE_UTMP(safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));)
+ fromhost = xasprintf(" on '%s' from '%s'", short_tty, opt_host);
+ } else {
+ fromhost = xasprintf(" on '%s'", short_tty);
+ }
-#ifdef CONFIG_FEATURE_U_W_TMP
-// vv Taken from tinylogin utmp.c vv
-
-#define _WTMP_FILE "/var/log/wtmp"
-
-#define NO_UTENT \
- "No utmp entry. You must exec \"login\" from the lowest level \"sh\""
-#define NO_TTY \
- "Unable to determine your tty name."
-
-/*
- * checkutmp - 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.
- */
+ /* Was breaking "login <username>" from shell command line: */
+ /*bb_setpgrp();*/
-static void checkutmp(int picky)
-{
- char *line;
- struct utmp *ut;
- pid_t pid = getpid();
+ openlog(applet_name, LOG_PID | LOG_CONS, LOG_AUTH);
- setutent();
+ while (1) {
+ /* flush away any type-ahead (as getty does) */
+ ioctl(0, TCFLSH, TCIFLUSH);
- /* 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 (!username[0])
+ get_username_or_die(username, sizeof(username));
- /* If there is one, just use it, otherwise create a new one. */
- if (ut) {
- utent = *ut;
- } else {
- if (picky) {
- puts(NO_UTENT);
- exit(1);
+#if ENABLE_PAM
+ pamret = pam_start("login", username, &conv, &pamh);
+ if (pamret != PAM_SUCCESS) {
+ failed_msg = "start";
+ goto pam_auth_failed;
}
- line = ttyname(0);
- if (!line) {
- puts(NO_TTY);
- exit(1);
+ /* set TTY (so things like securetty work) */
+ pamret = pam_set_item(pamh, PAM_TTY, short_tty);
+ if (pamret != PAM_SUCCESS) {
+ failed_msg = "set_item(TTY)";
+ 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)
+ */
+ }
+ /* check that the account is healthy */
+ pamret = pam_acct_mgmt(pamh, 0);
+ if (pamret != PAM_SUCCESS) {
+ failed_msg = "acct_mgmt";
+ goto pam_auth_failed;
+ }
+ /* read user back */
+ pamuser = NULL;
+ /* gcc: "dereferencing type-punned pointer breaks aliasing rules..."
+ * thus we cast to (void*) */
+ if (pam_get_item(pamh, PAM_USER, (void*)&pamuser) != PAM_SUCCESS) {
+ failed_msg = "get_item(USER)";
+ goto pam_auth_failed;
+ }
+ if (!pamuser || !pamuser[0])
+ goto auth_failed;
+ safe_strncpy(username, pamuser, sizeof(username));
+ /* Don't use "pw = getpwnam(username);",
+ * PAM is said to be capable of destroying static storage
+ * used by getpwnam(). We are using safe(r) function */
+ pw = NULL;
+ getpwnam_r(username, &pwdstruct, pwdbuf, sizeof(pwdbuf), &pw);
+ if (!pw)
+ goto auth_failed;
+ pamret = pam_open_session(pamh, 0);
+ if (pamret != PAM_SUCCESS) {
+ failed_msg = "open_session";
+ goto pam_auth_failed;
+ }
+ pamret = pam_setcred(pamh, PAM_ESTABLISH_CRED);
+ if (pamret != PAM_SUCCESS) {
+ failed_msg = "setcred";
+ goto pam_auth_failed;
+ }
+ break; /* success, continue login process */
+
+ pam_auth_failed:
+ /* syslog, because we don't want potential attacker
+ * to know _why_ login failed */
+ syslog(LOG_WARNING, "pam_%s call failed: %s (%d)", failed_msg,
+ pam_strerror(pamh, pamret), pamret);
+ safe_strncpy(username, "UNKNOWN", sizeof(username));
+#else /* not PAM */
+ pw = getpwnam(username);
+ if (!pw) {
+ strcpy(username, "UNKNOWN");
+ goto fake_it;
}
- if (strncmp(line, "/dev/", 5) == 0)
- line += 5;
- memset((void *) &utent, 0, sizeof utent);
- utent.ut_type = LOGIN_PROCESS;
- utent.ut_pid = pid;
- strncpy(utent.ut_line, line, sizeof utent.ut_line);
- /* XXX - assumes /dev/tty?? */
- strncpy(utent.ut_id, utent.ut_line + 3, sizeof utent.ut_id);
- strncpy(utent.ut_user, "LOGIN", sizeof utent.ut_user);
- time(&utent.ut_time);
- }
-}
-/*
- * setutmp - put a USER_PROCESS entry in the utmp file
- *
- * setutmp changes the type of the current utmp entry to
- * USER_PROCESS. the wtmp file will be updated as well.
- */
+ if (pw->pw_passwd[0] == '!' || pw->pw_passwd[0] == '*')
+ goto auth_failed;
-static void setutmp(const char *name, const char *line)
-{
- utent.ut_type = USER_PROCESS;
- strncpy(utent.ut_user, name, sizeof utent.ut_user);
- time(&utent.ut_time);
- /* other fields already filled in by checkutmp above */
- setutent();
- pututline(&utent);
- endutent();
- updwtmp(_WTMP_FILE, &utent);
+ 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;
+ fake_it:
+ /* authorization takes place here */
+ if (correct_password(pw))
+ break;
+#endif /* ENABLE_PAM */
+ auth_failed:
+ opt &= ~LOGIN_OPT_f;
+ bb_do_delay(FAIL_DELAY);
+ /* TODO: doesn't sound like correct English phrase to me */
+ puts("Login incorrect");
+ if (++count == 3) {
+ syslog(LOG_WARNING, "invalid password for '%s'%s",
+ username, fromhost);
+ return EXIT_FAILURE;
+ }
+ username[0] = '\0';
+ } /* while (1) */
+
+ alarm(0);
+ /* We can ignore /etc/nologin if we are logging in as root,
+ * it doesn't matter whether we are run by root or not */
+ if (pw->pw_uid != 0)
+ die_if_nologin();
+
+ write_utent(&utent, username);
+
+ 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); */
+ fchown(0, pw->pw_uid, pw->pw_gid);
+ fchmod(0, 0600);
+
+ /* We trust environment only if we run by root */
+ if (ENABLE_LOGIN_SCRIPTS && run_by_root)
+ run_login_script(pw, full_tty);
+
+ change_identity(pw);
+ tmp = pw->pw_shell;
+ if (!tmp || !*tmp)
+ tmp = DEFAULT_SHELL;
+ /* setup_environment params: shell, clear_env, change_env, pw */
+ setup_environment(tmp, !(opt & LOGIN_OPT_p), 1, pw);
+
+ motd();
+
+ if (pw->pw_uid == 0)
+ syslog(LOG_INFO, "root login%s", fromhost);
+
+ /* well, a simple setexeccon() here would do the job as well,
+ * but let's play the game for now */
+ IF_SELINUX(set_current_security_context(user_sid);)
+
+ // util-linux login also does:
+ // /* start new session */
+ // setsid();
+ // /* TIOCSCTTY: steal tty from other process group */
+ // if (ioctl(0, TIOCSCTTY, 1)) error_msg...
+ // BBox login used to do this (see above):
+ // bb_setpgrp();
+ // If this stuff is really needed, add it and explain why!
+
+ /* Set signals to defaults */
+ /* Non-ignored signals revert to SIG_DFL on exec anyway */
+ /*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 we leave SIGINT etc enabled or disabled? */
+ signal(SIGINT, SIG_DFL);
+
+ /* Exec login shell with no additional parameters */
+ run_shell(tmp, 1, NULL, NULL);
+
+ /* return EXIT_FAILURE; - not reached */
}
-#endif /* CONFIG_FEATURE_U_W_TMP */