login.c

Util-linux 软件包包含许多工具。其中比较重要的是加载、卸载、格式化、分区和管理硬盘驱动器

/* This program is derived from 4.3 BSD software and is
   subject to the copyright notice below.
   
   The port to HP-UX has been motivated by the incapability
   of 'rlogin'/'rlogind' as per HP-UX 6.5 (and 7.0) to transfer window sizes.
   
   Changes:
   
   - General HP-UX portation. Use of facilities not available
     in HP-UX (e.g. setpriority) has been eliminated.
     Utmp/wtmp handling has been ported.
   
   - The program uses BSD command line options to be used
     in connection with e.g. 'rlogind' i.e. 'new login'.
   
   - HP features left out:	    password expiry
				    '*' as login shell, add it if you need it

   - BSD features left out:         quota checks
   	                            password expiry
				    analysis of terminal type (tset feature)
   
   - BSD features thrown in:        Security logging to syslogd.
                                    This requires you to have a (ported) syslog
				    system -- 7.0 comes with syslog
   
				    'Lastlog' feature.
   
   - A lot of nitty gritty details have been adjusted in favour of
     HP-UX, e.g. /etc/securetty, default paths and the environment
     variables assigned by 'login'.
   
   - We do *nothing* to setup/alter tty state, under HP-UX this is
     to be done by getty/rlogind/telnetd/some one else.
   
   Michael Glad ([e-mail])
   Computer Science Department
   Aarhus University
   Denmark
   
   1990-07-04
   
   1991-09-24 [e-mail]: HP-UX 8.0 port:
   - now explictly sets non-blocking mode on descriptors
   - strcasecmp is now part of HP-UX

   1992-02-05 [e-mail]: Ported the stuff to Linux 0.12
   From 1992 till now (1997) this code for Linux has been maintained at
   ftp.daimi.aau.dk:/pub/linux/poe/

   1999-02-22 Arkadiusz Mi秌iewicz <[e-mail]>
    - added Native Language Support
   Sun Mar 21 1999 - Arnaldo Carvalho de Melo <[e-mail]>
    - fixed strerr(errno) in gettext calls
 */

/*
 * Copyright (c) 1980, 1987, 1988 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

/*
 * login [ name ]
 * login -h hostname	(for telnetd, etc.)
 * login -f name	(for pre-authenticated login: datakit, xterm, etc.)
 */

/* #define TESTING */

#ifdef TESTING
#include "param.h"
#else
#include <sys/param.h>
#endif

#include <stdio.h>
#include <ctype.h>
#include <unistd.h>
#include <getopt.h>
#include <memory.h>
#include <time.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/file.h>
#include <termios.h>
#include <string.h>
#define index strchr
#define rindex strrchr
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <signal.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <utmp.h>
#include <setjmp.h>
#include <stdlib.h>
#include <string.h>
#include <sys/syslog.h>
#include <sys/sysmacros.h>
#include <netdb.h>
#include "pathnames.h"
#include "my_crypt.h"
#include "login.h"
#include "xstrncpy.h"
#include "nls.h"

#ifdef __linux__
#  include <sys/sysmacros.h>
#  include <linux/major.h>
#endif

#ifdef TESTING
#  include "utmp.h"
#else
#  include <utmp.h>
#endif

#ifdef SHADOW_PWD
#  include <shadow.h>
#endif

#ifdef USE_PAM
#  include <security/pam_appl.h>
#  include <security/pam_misc.h>
#  define PAM_MAX_LOGIN_TRIES	3
#  define PAM_FAIL_CHECK if (retcode != PAM_SUCCESS) { \
       fprintf(stderr,"\n%s\n",pam_strerror(pamh, retcode)); \
       syslog(LOG_ERR,"%s",pam_strerror(pamh, retcode)); \
       pam_end(pamh, retcode); exit(1); \
   }
#  define PAM_END { \
	pam_setcred(pamh, PAM_DELETE_CRED); \
	retcode = pam_close_session(pamh,0); \
	pam_end(pamh,retcode); \
}
#endif

#ifndef __linux__
#  include <tzfile.h>
#endif
#include <lastlog.h>

#define SLEEP_EXIT_TIMEOUT 5

#ifdef __linux__
#define DO_PS_FIDDLING
#endif

#ifdef DO_PS_FIDDLING
#include "setproctitle.h"
#endif

#if 0
/* from before we had a lastlog.h file in linux */
struct  lastlog
{ long ll_time;
  char ll_line[12];
  char ll_host[16];
};
#endif

#ifndef USE_PAM
static void getloginname (void);
static void checknologin (void);
static int rootterm (char *ttyn);
#endif
static void timedout (int);
static void sigint (int);
static void motd (void);
static void dolastlog (int quiet);

#ifdef CRYPTOCARD
#include "cryptocard.h"
#endif

#ifdef	KERBEROS
#include <kerberos/krb.h>
#include <sys/termios.h>
char	realm[REALM_SZ];
int	kerror = KSUCCESS, notickets = 1;
#endif

#ifdef USE_TTY_GROUP
#  define TTY_MODE 0620
#else
#  define TTY_MODE 0600
#endif

#define	TTYGRPNAME	"tty"		/* name of group to own ttys */

#ifndef MAXPATHLEN
#  define MAXPATHLEN 1024
#endif

/*
 * This bounds the time given to login.  Not a define so it can
 * be patched on machines where it's too small.
 */
#ifndef __linux__
int	timeout = 300;
#else
int     timeout = 60;		/* used in cryptocard.c */
#endif

struct	passwd *pwd;		/* used in cryptocard.c */
#if USE_PAM
static struct passwd pwdcopy;
#endif
char    hostaddress[4];		/* used in checktty.c */
char	*hostname;		/* idem */
static char	*username, *tty_name, *tty_number;
static char	thishost[100];
static int	failures = 1;
static pid_t	pid;

#ifndef __linux__
struct	sgttyb sgttyb;
struct	tchars tc = {
	CINTR, CQUIT, CSTART, CSTOP, CEOT, CBRK
};
struct	ltchars ltc = {
	CSUSP, CDSUSP, CRPRNT, CFLUSH, CWERASE, CLNEXT
};
#endif

/* Nice and simple code provided by Linus Torvalds 16-Feb-93 */
/* Nonblocking stuff by Maciej W. Rozycki, [e-mail], 1999.
   He writes: "Login performs open() on a tty in a blocking mode.
   In some cases it may make login wait in open() for carrier infinitely,
   for example if the line is a simplistic case of a three-wire serial
   connection. I believe login should open the line in the non-blocking mode
   leaving the decision to make a connection to getty (where it actually
   belongs). */
static void
opentty(const char * tty) {
	int i, fd, flags;

	fd = open(tty, O_RDWR | O_NONBLOCK);
	if (fd == -1) {
		syslog(LOG_ERR, _("FATAL: can't reopen tty: %s"),
		       strerror(errno));
		sleep(1);
		exit(1);
	}

	flags = fcntl(fd, F_GETFL);
	flags &= ~O_NONBLOCK;
	fcntl(fd, F_SETFL, flags);
    
	for (i = 0; i < fd; i++)
		close(i);
	for (i = 0; i < 3; i++)
		if (fd != i)
			dup2(fd, i);
	if (fd >= 3)
		close(fd);
}

/* In case login is suid it was possible to use a hardlink as stdin
   and exploit races for a local root exploit. (Wojciech Purczynski). */
/* More precisely, the problem is  ttyn := ttyname(0); ...; chown(ttyn);
   here ttyname() might return "/tmp/x", a hardlink to a pseudotty. */
/* All of this is a problem only when login is suid, which it isnt. */
static void
check_ttyname(char *ttyn) {
	struct stat statbuf;

	if (lstat(ttyn, &statbuf)
	    || !S_ISCHR(statbuf.st_mode)
	    || (statbuf.st_nlink > 1 && strncmp(ttyn, "/dev/", 5))) {
		syslog(LOG_ERR, _("FATAL: bad tty"));
		sleep(1);
		exit(1);
	}
}

/* true if the filedescriptor fd is a console tty, very Linux specific */
static int
consoletty(int fd) {
#ifdef __linux__
    struct stat stb;

    if ((fstat(fd, &stb) >= 0) 
	&& (major(stb.st_rdev) == TTY_MAJOR)
	&& (minor(stb.st_rdev) < 64)) {
	return 1;
    }
#endif
    return 0;
}

#if USE_PAM
/*
 * Log failed login attempts in _PATH_BTMP if that exists.
 * Must be called only with username the name of an actual user.
 * The most common login failure is to give password instead of username.
 */
#define	_PATH_BTMP	"/var/log/btmp"
static void
logbtmp(const char *line, const char *username, const char *hostname) {
	struct utmp ut;

	memset(&ut, 0, sizeof(ut));

	strncpy(ut.ut_user, username ? username : "(unknown)",
		sizeof(ut.ut_user));

	strncpy(ut.ut_id, line + 3, sizeof(ut.ut_id));
	xstrncpy(ut.ut_line, line, sizeof(ut.ut_line));

#if defined(_HAVE_UT_TV)	    /* in <utmpbits.h> included by <utmp.h> */
	gettimeofday(&ut.ut_tv, NULL);
#else
	{
		time_t t;
		time(&t);
		ut.ut_time = t;	    /* ut_time is not always a time_t */
	}
#endif

	ut.ut_type = LOGIN_PROCESS; /* XXX doesn't matter */
	ut.ut_pid = pid;
	if (hostname) {
		xstrncpy(ut.ut_host, hostname, sizeof(ut.ut_host));
		if (hostaddress[0])
			memcpy(&ut.ut_addr, hostaddress, sizeof(ut.ut_addr));
	}
#ifdef HAVE_updwtmp		/* bad luck for ancient systems */
	updwtmp(_PATH_BTMP, &ut);
#endif
}
#endif	/* USE_PAM */

int
main(int argc, char **argv)
{
    extern int optind;
    extern char *optarg, **environ;
    struct group *gr;
    register int ch;
    register char *p;
    int ask, fflag, hflag, pflag, cnt, errsv;
    int quietlog, passwd_req;
    char *domain, *ttyn;
    char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10];
    char *termenv;
    char *childArgv[10];
    char *buff;
    int childArgc = 0;
#ifdef USE_PAM
    int retcode;
    pam_handle_t *pamh = NULL;
    struct pam_conv conv = { misc_conv, NULL };
    pid_t childPid;
#else
    char *salt, *pp;
#endif
#ifdef CHOWNVCS
    char vcsn[20], vcsan[20];
#endif

    pid = getpid();

    signal(SIGALRM, timedout);
    alarm((unsigned int)timeout);
    signal(SIGQUIT, SIG_IGN);
    signal(SIGINT, SIG_IGN);

    setlocale(LC_ALL, "");
    bindtextdomain(PACKAGE, LOCALEDIR);
    textdomain(PACKAGE);
    
    setpriority(PRIO_PROCESS, 0, 0);
#ifdef HAVE_QUOTA
    quota(Q_SETUID, 0, 0, 0);
#endif
#ifdef DO_PS_FIDDLING
    initproctitle(argc, argv);
#endif
    
    /*
     * -p is used by getty to tell login not to destroy the environment
     * -f is used to skip a second login authentication 
     * -h is used by other servers to pass the name of the remote
     *    host to login so that it may be placed in utmp and wtmp
     */
    gethostname(tbuf, sizeof(tbuf));
    xstrncpy(thishost, tbuf, sizeof(thishost));
    domain = index(tbuf, '.');
    
    username = tty_name = hostname = NULL;
    fflag = hflag = pflag = 0;
    passwd_req = 1;

    while ((ch = getopt(argc, argv, "fh:p")) != -1)
      switch (ch) {
	case 'f':
	  fflag = 1;
	  break;
	  
	case 'h':
	  if (getuid()) {
	      fprintf(stderr,
		      _("login: -h for super-user only.\n"));
	      exit(1);
	  }
	  hflag = 1;
	  if (domain && (p = index(optarg, '.')) &&
	      strcasecmp(p, domain) == 0)
	    *p = 0;

	  hostname = strdup(optarg); 	/* strdup: Ambrose C. Li */
	  {
		  struct hostent *he = gethostbyname(hostname);

		  /* he points to static storage; copy the part we use */
		  hostaddress[0] = 0;
		  if (he && he->h_addr_list && he->h_addr_list[0])
			  memcpy(hostaddress, he->h_addr_list[0],
				 sizeof(hostaddress));
	  }
	  break;
	  
	case 'p':
	  pflag = 1;
	  break;

	case '?':
	default:
	  fprintf(stderr,
		  _("usage: login [-fp] [username]\n"));
	  exit(1);
      }
    argc -= optind;
    argv += optind;
    if (*argv) {
	char *p = *argv;
	username = strdup(p);
	ask = 0;
	/* wipe name - some people mistype their password here */
	/* (of course we are too late, but perhaps this helps a little ..) */
	while(*p)
	    *p++ = ' ';
    } else
        ask = 1;

    for (cnt = getdtablesize(); cnt > 2; cnt--)
      close(cnt);
    
    ttyn = ttyname(0);

    if (ttyn == NULL || *ttyn == '\0') {
	/* no snprintf required - see definition of tname */
	sprintf(tname, "%s??", _PATH_TTY);
	ttyn = tname;
    }

    check_ttyname(ttyn);

    if (strncmp(ttyn, "/dev/", 5) == 0)
	tty_name = ttyn+5;
    else