busybox/loginutils/login.c
Robert Griebl 1fca558799 Bigger patch for (partial) tinylogin integration
- Made a new dir loginutils
- Moved all applets from pwd_grp to loginutils
- Added new applets su.c login.c to loginutils
- Made a new dir libpwdgrp
- Moved everything from pwd_grp/libpwd_grp there
- Added shadow.c to libpwdgrp
- Removed dir pwd_grp
- Added usage strings for login and su to usage.h
- Changed main Makefile to reflect the dir rearrangements
[Parts of this patch may overlap with my other two patches]
2002-06-04 20:45:46 +00:00

460 lines
9.7 KiB
C

/* 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"
#include "pwd.h"
#include "grp.h"
#ifdef CONFIG_FEATURE_SHADOWPASSWDS
#include "shadow.h"
#endif
#include "tinylogin.h"
// import from utmp.c
static void checkutmp(int picky);
static void setutmp(const char *name, const char *line);
// import from encrypt.c
extern char *pw_encrypt(const char *clear, const char *salt);
// login defines
#define DEFAULT_USER "UNKNOWN"
#define DEFAULT_PWD "!"
#define DEFAULT_SHELL "/bin/sh"
#define TIMEOUT 60
#define FAIL_DELAY 3
#define MOTD_FILE "/etc/motd"
#define NOLOGIN_FILE "/etc/nologin"
#define SECURETTY_FILE "/etc/securetty"
/* Stuff global to this file */
struct utmp utent;
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 const char *login_prompt ( void );
static void motd ( void );
static void set_env(int argc, char *const *argv);
static void alarm_handler ( int sig )
{
error_msg ( "\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 *tmp;
int amroot;
int flag;
int failed;
int count=0;
struct passwd *pw, pw_copy;
int opt_preserve = 0;
int opt_fflag = 0;
char *opt_host = 0;
const char *username = 0;
int alarmstarted = 0;
amroot = ( getuid ( ) == 0 );
signal ( SIGALRM, alarm_handler );
if (( argc > 1 ) && ( TIMEOUT > 0 )) {
alarm ( TIMEOUT );
alarmstarted = 1;
}
while (( flag = getopt(argc, argv, "f:h:p")) != EOF ) {
switch ( flag ) {
case 'p':
printf ( "PRESERVE\n" );
opt_preserve = 1;
break;
case 'f':
/*
* username must be a seperate token
* (-f root, *NOT* -froot). --marekm
*/
if ( optarg != argv[optind-1] )
show_usage ( );
if ( !amroot ) /* Auth bypass only if real UID is zero */
error_msg_and_die ( "login: -f permission denied\n" );
printf ( "USERNAME: %s\n", optarg );
username = optarg;
opt_fflag = 1;
break;
case 'h':
opt_host = optarg;
break;
default:
show_usage ( );
}
}
if ( optind < argc ) // got a username
username = argv [optind++];
if ( !isatty ( 0 ) || !isatty ( 1 ) || !isatty ( 2 ))
return EXIT_FAILURE; /* Must be a terminal */
checkutmp ( !amroot );
tmp = ttyname ( 0 );
if ( tmp && ( strncmp ( tmp, "/dev/", 5 ) == 0 ))
safe_strncpy ( tty, tmp + 5, sizeof( tty ));
else
safe_strncpy ( tty, "UNKNOWN", sizeof( tty ));
if ( amroot )
memset ( utent.ut_host, 0, sizeof utent.ut_host );
if ( opt_host ) {
safe_strncpy ( utent.ut_host, opt_host, sizeof( utent. ut_host ));
snprintf ( fromhost, sizeof( fromhost ) - 1, " on `%.100s' from `%.200s'", tty, opt_host );
}
else
snprintf ( fromhost, sizeof( fromhost ) - 1, " on `%.100s'", tty );
openlog ( "login", LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH );
while ( 1 ) {
failed = 0;
if ( !username || !username[0] )
username = login_prompt ( );
if ( !alarmstarted && ( TIMEOUT > 0 )) {
alarm ( TIMEOUT );
alarmstarted = 1;
}
if (!( pw = getpwnam ( username ))) {
pw_copy. pw_name = DEFAULT_USER;
pw_copy. pw_passwd = DEFAULT_PWD;
pw_copy. pw_shell = DEFAULT_SHELL;
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 (( 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;
syslog ( LOG_WARNING, "invalid password for `%s'%s\n", pw-> pw_name, fromhost);
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");
if ( ++count == 3 )
return EXIT_FAILURE;
}
alarm ( 0 );
if ( check_nologin ( pw-> pw_uid == 0 ))
return EXIT_FAILURE;
setutmp ( username, tty );
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 ); /* exec the shell finally. */
return EXIT_FAILURE;
}
static const char *login_prompt ( void )
{
char buf [1024];
char *sp, *ep;
gethostname ( buf, sizeof( buf ));
printf ( "\nBusyBox on %s login: ", buf );
fflush ( stdout );
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;
return sp;
}
static int check_nologin ( int amroot )
{
if ( access ( NOLOGIN_FILE, F_OK ) == 0 ) {
FILE *fp;
int c;
if (( fp = fopen ( 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 ( SECURETTY_FILE, "r" ))) {
while ( fgets ( buf, sizeof( buf ) - 1, fp )) {
for ( i = xstrlen( 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;
}
else {
syslog ( LOG_WARNING, "cannot open securetty file.\n" );
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 ( MOTD_FILE, "r" ))) {
while (( c = getc ( fp )) != EOF )
putchar ( c );
fclose ( fp );
}
}
// 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);
}
}
#if __GNU_LIBRARY__ < 5
/*
* Some systems already have updwtmp() and possibly updwtmpx(). Others
* don't, so we re-implement these functions if necessary. --marekm
*/
static void updwtmp(const char *filename, const struct utmp *ut)
{
int fd;
fd = open(filename, O_APPEND | O_WRONLY, 0);
if (fd >= 0) {
write(fd, (const char *) ut, sizeof(*ut));
close(fd);
}
}
#endif
/*
* 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);
}