diff options
Diffstat (limited to 'release/src/router/busybox/loginutils/login.c')
| -rw-r--r-- | release/src/router/busybox/loginutils/login.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/release/src/router/busybox/loginutils/login.c b/release/src/router/busybox/loginutils/login.c new file mode 100644 index 00000000..c2bada25 --- /dev/null +++ b/release/src/router/busybox/loginutils/login.c @@ -0,0 +1,481 @@ +/* vi: set sw=4 ts=4: */ +#include <fcntl.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.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; +#endif + +// login defines +#define TIMEOUT 60 +#define EMPTY_USERNAME_COUNT 10 +#define USERNAME_SIZE 32 + + +static int check_nologin ( int amroot ); + +#if defined CONFIG_FEATURE_SECURETTY +static int check_tty ( const char *tty ); + +#else +static inline int check_tty ( const char *tty ) { return 1; } + +#endif + +static int is_my_tty ( const char *tty ); +static int login_prompt ( char *buf_name ); +static void motd ( void ); + + +static void alarm_handler ( int sig ) +{ + fprintf (stderr, "\nLogin timed out after %d seconds.\n", TIMEOUT ); + exit ( EXIT_SUCCESS ); +} + + +extern int login_main(int argc, char **argv) +{ + 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; +#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; + break; + default: + bb_show_usage( ); + } + } + + 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 )); +#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; + + { // delay next try + time_t start, now; + + time ( &start ); + now = start; + while ( difftime ( now, start ) < FAIL_DELAY) { + sleep ( FAIL_DELAY ); + time ( &now ); + } + } + + 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; + } + } + + 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; + } + } + 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; +} + + + +static int login_prompt ( char *buf_name ) +{ + 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; + } + return 0; +} + + +static int check_nologin ( int amroot ) +{ + 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" ); + } + if ( !amroot ) + return 1; + + puts ( "\r\n[Disconnect bypassed -- root login allowed.]\r" ); + } + return 0; +} + +#ifdef CONFIG_FEATURE_SECURETTY + +static int check_tty ( const char *tty ) +{ + 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; + } + /* A missing securetty file is not an error. */ + return 1; +} + +#endif + +/* returns 1 if true */ +static int is_my_tty ( const char *tty ) +{ + 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; +} + + +static void motd ( ) +{ + FILE *fp; + register int c; + + if (( fp = fopen ( bb_path_motd_file, "r" ))) { + while (( c = getc ( fp )) != EOF ) + putchar ( c ); + fclose ( fp ); + } +} + + +#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. + */ + +static void checkutmp(int picky) +{ + char *line; + 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) { + puts(NO_UTENT); + exit(1); + } + line = ttyname(0); + if (!line) { + puts(NO_TTY); + exit(1); + } + 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. + */ + +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); +} +#endif /* CONFIG_FEATURE_U_W_TMP */ |