freebsd-dev/usr.bin/login/login.c
Garrett Wollman 758f3a64bd Modify klogin to:
1) Don't spit out an error message if Kerberos is installed but not yet
   set up.

2) Don't attempt to verify the ticket you got back, as workstations
   are not intended to have srvtab files of their own.

Both behaviors can be re-enabled with KLOGIN_PARANOID.
1995-01-14 22:57:41 +00:00

669 lines
16 KiB
C

/*-
* Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94";
#endif /* not lint */
/*
* login [ name ]
* login -h hostname (for telnetd, etc.)
* login -f name (for pre-authenticated login: datakit, xterm, etc.)
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/file.h>
#include <err.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <ttyent.h>
#include <tzfile.h>
#include <unistd.h>
#include <utmp.h>
#ifdef SKEY
#include <skey.h>
#endif
#include "pathnames.h"
void badlogin __P((char *));
void checknologin __P((void));
void dolastlog __P((int));
void getloginname __P((void));
void motd __P((void));
int rootterm __P((char *));
void sigint __P((int));
void sleepexit __P((int));
char *stypeof __P((char *));
void timedout __P((int));
void login_fbtab __P((char *, uid_t, gid_t));
#ifdef KERBEROS
int klogin __P((struct passwd *, char *, char *, char *));
#endif
extern void login __P((struct utmp *));
#define TTYGRPNAME "tty" /* name of group to own ttys */
/*
* This bounds the time given to login. Not a define so it can
* be patched on machines where it's too small.
*/
u_int timeout = 300;
#ifdef KERBEROS
int notickets = 1;
int noticketsdontcomplain = 1;
char *instance;
char *krbtkfile_env;
int authok;
#endif
struct passwd *pwd;
int failures;
char term[64], *envinit[1], *hostname, *username, *tty;
int
main(argc, argv)
int argc;
char *argv[];
{
extern char **environ;
struct group *gr;
struct stat st;
struct timeval tp;
struct utmp utmp;
int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval;
int changepass;
uid_t uid;
char *domain, *p, *ep, *salt, *ttyn;
char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10];
char localhost[MAXHOSTNAMELEN];
char full_hostname[MAXHOSTNAMELEN];
#ifdef SKEY
int permit_passwd = 0;
#endif
(void)signal(SIGALRM, timedout);
(void)alarm(timeout);
(void)signal(SIGQUIT, SIG_IGN);
(void)signal(SIGINT, SIG_IGN);
(void)setpriority(PRIO_PROCESS, 0, 0);
openlog("login", LOG_ODELAY, LOG_AUTH);
/*
* -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
*/
*full_hostname = '\0';
domain = NULL;
if (gethostname(localhost, sizeof(localhost)) < 0)
syslog(LOG_ERR, "couldn't get local hostname: %m");
else
domain = strchr(localhost, '.');
fflag = hflag = pflag = 0;
uid = getuid();
while ((ch = getopt(argc, argv, "fh:p")) != EOF)
switch (ch) {
case 'f':
fflag = 1;
break;
case 'h':
if (uid)
errx(1, "-h option: %s", strerror(EPERM));
hflag = 1;
strncpy(full_hostname, optarg, sizeof(full_hostname)-1);
if (domain && (p = strchr(optarg, '.')) &&
strcasecmp(p, domain) == 0)
*p = 0;
hostname = optarg;
break;
case 'p':
pflag = 1;
break;
case '?':
default:
if (!uid)
syslog(LOG_ERR, "invalid flag %c", ch);
(void)fprintf(stderr,
"usage: login [-fp] [-h hostname] [username]\n");
exit(1);
}
argc -= optind;
argv += optind;
if (*argv) {
username = *argv;
ask = 0;
} else
ask = 1;
for (cnt = getdtablesize(); cnt > 2; cnt--)
(void)close(cnt);
ttyn = ttyname(STDIN_FILENO);
if (ttyn == NULL || *ttyn == '\0') {
(void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
ttyn = tname;
}
if (tty = strrchr(ttyn, '/'))
++tty;
else
tty = ttyn;
for (cnt = 0;; ask = 1) {
if (ask) {
fflag = 0;
getloginname();
}
rootlogin = 0;
#ifdef KERBEROS
if ((instance = strchr(username, '.')) != NULL) {
if (strncmp(instance, ".root", 5) == 0)
rootlogin = 1;
*instance++ = '\0';
} else
instance = "";
#endif
if (strlen(username) > UT_NAMESIZE)
username[UT_NAMESIZE] = '\0';
/*
* Note if trying multiple user names; log failures for
* previous user name, but don't bother logging one failure
* for nonexistent name (mistyped username).
*/
if (failures && strcmp(tbuf, username)) {
if (failures > (pwd ? 0 : 1))
badlogin(tbuf);
failures = 0;
}
(void)strcpy(tbuf, username);
if (pwd = getpwnam(username))
salt = pwd->pw_passwd;
else
salt = "xx";
/*
* if we have a valid account name, and it doesn't have a
* password, or the -f option was specified and the caller
* is root or the caller isn't changing their uid, don't
* authenticate.
*/
if (pwd) {
if (pwd->pw_uid == 0)
rootlogin = 1;
if (fflag && (uid == 0 || uid == pwd->pw_uid)) {
/* already authenticated */
break;
} else if (pwd->pw_passwd[0] == '\0') {
/* pretend password okay */
rval = 0;
goto ttycheck;
}
}
fflag = 0;
(void)setpriority(PRIO_PROCESS, 0, -4);
#ifdef SKEY
permit_passwd = skeyaccess(username, tty,
hostname ? full_hostname : NULL,
NULL);
p = skey_getpass("Password:", pwd, permit_passwd);
ep = skey_crypt(p, salt, pwd, permit_passwd);
#else
p = getpass("Password:");
ep = crypt(p, salt);
#endif
if (pwd) {
#ifdef KERBEROS
rval = klogin(pwd, instance, localhost, p);
if (rval != 0 && rootlogin && pwd->pw_uid != 0)
rootlogin = 0;
if (rval == 0)
authok = 1;
else if (rval == 1)
rval = strcmp(ep, pwd->pw_passwd);
#else
rval = strcmp(ep, pwd->pw_passwd);
#endif
}
memset(p, 0, strlen(p));
(void)setpriority(PRIO_PROCESS, 0, 0);
ttycheck:
/*
* If trying to log in as root without Kerberos,
* but with insecure terminal, refuse the login attempt.
*/
#ifdef KERBEROS
if (authok == 0)
#endif
if (pwd && !rval && rootlogin && !rootterm(tty)) {
(void)fprintf(stderr,
"%s login refused on this terminal.\n",
pwd->pw_name);
if (hostname)
syslog(LOG_NOTICE,
"LOGIN %s REFUSED FROM %s ON TTY %s",
pwd->pw_name, hostname, tty);
else
syslog(LOG_NOTICE,
"LOGIN %s REFUSED ON TTY %s",
pwd->pw_name, tty);
continue;
}
if (pwd && !rval)
break;
(void)printf("Login incorrect\n");
failures++;
/* we allow 10 tries, but after 3 we start backing off */
if (++cnt > 3) {
if (cnt >= 10) {
badlogin(username);
sleepexit(1);
}
sleep((u_int)((cnt - 3) * 5));
}
}
/* committed to login -- turn off timeout */
(void)alarm((u_int)0);
endpwent();
/* if user not super-user, check for disabled logins */
if (!rootlogin)
checknologin();
if (chdir(pwd->pw_dir) < 0) {
(void)printf("No home directory %s!\n", pwd->pw_dir);
if (chdir("/"))
exit(0);
pwd->pw_dir = "/";
(void)printf("Logging in with home = \"/\".\n");
}
quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
if (pwd->pw_change || pwd->pw_expire)
(void)gettimeofday(&tp, (struct timezone *)NULL);
changepass=0;
if (pwd->pw_change)
if (tp.tv_sec >= pwd->pw_change) {
(void)printf("Sorry -- your password has expired.\n");
changepass=1;
} else if (pwd->pw_change - tp.tv_sec <
2 * DAYSPERWEEK * SECSPERDAY && !quietlog)
(void)printf("Warning: your password expires on %s",
ctime(&pwd->pw_change));
if (pwd->pw_expire)
if (tp.tv_sec >= pwd->pw_expire) {
(void)printf("Sorry -- your account has expired.\n");
sleepexit(1);
} else if (pwd->pw_expire - tp.tv_sec <
2 * DAYSPERWEEK * SECSPERDAY && !quietlog)
(void)printf("Warning: your account expires on %s",
ctime(&pwd->pw_expire));
/* Nothing else left to fail -- really log in. */
memset((void *)&utmp, 0, sizeof(utmp));
(void)time(&utmp.ut_time);
(void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name));
if (hostname)
(void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
(void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
login(&utmp);
dolastlog(quietlog);
/*
* Set device protections, depending on what terminal the
* user is logged in. This feature is used on Suns to give
* console users better privacy.
*/
login_fbtab(tty, pwd->pw_uid, pwd->pw_gid);
(void)chown(ttyn, pwd->pw_uid,
(gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid);
(void)setgid(pwd->pw_gid);
initgroups(username, pwd->pw_gid);
if (*pwd->pw_shell == '\0')
pwd->pw_shell = _PATH_BSHELL;
/* Destroy environment unless user has requested its preservation. */
if (!pflag)
environ = envinit;
(void)setenv("HOME", pwd->pw_dir, 1);
(void)setenv("SHELL", pwd->pw_shell, 1);
if (term[0] == '\0')
(void)strncpy(term, stypeof(tty), sizeof(term));
(void)setenv("TERM", term, 0);
(void)setenv("LOGNAME", pwd->pw_name, 1);
(void)setenv("USER", pwd->pw_name, 1);
(void)setenv("PATH", _PATH_DEFPATH, 0);
#ifdef KERBEROS
if (krbtkfile_env)
(void)setenv("KRBTKFILE", krbtkfile_env, 1);
#endif
if (tty[sizeof("tty")-1] == 'd')
syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
/* If fflag is on, assume caller/authenticator has logged root login. */
if (rootlogin && fflag == 0)
if (hostname)
syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s",
username, tty, hostname);
else
syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty);
#ifdef KERBEROS
if (!quietlog && notickets == 1 && !noticketsdontcomplain)
(void)printf("Warning: no Kerberos tickets issued.\n");
#endif
#ifdef LOGALL
/*
* Syslog each successful login, so we don't have to watch hundreds
* of wtmp or lastlogin files.
*/
if (hostname) {
syslog(LOG_INFO, "login from %s as %s", hostname, pwd->pw_name);
} else {
syslog(LOG_INFO, "login on %s as %s", tty, pwd->pw_name);
}
#endif
if (!quietlog) {
(void)printf("%s\n\t%s %s\n\n",
"Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
"The Regents of the University of California. ",
"All rights reserved.");
motd();
(void)snprintf(tbuf,
sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name);
if (stat(tbuf, &st) == 0 && st.st_size != 0)
(void)printf("You have %smail.\n",
(st.st_mtime > st.st_atime) ? "new " : "");
}
#ifdef LOGIN_ACCESS
if (login_access(pwd->pw_name, hostname ? full_hostname : tty) == 0) {
printf("Permission denied\n");
if (hostname)
syslog(LOG_NOTICE, "%s LOGIN REFUSED FROM %s",
pwd->pw_name, hostname);
else
syslog(LOG_NOTICE, "%s LOGIN REFUSED ON %s",
pwd->pw_name, tty);
sleepexit(1);
}
#endif
(void)signal(SIGALRM, SIG_DFL);
(void)signal(SIGQUIT, SIG_DFL);
(void)signal(SIGINT, SIG_DFL);
(void)signal(SIGTSTP, SIG_IGN);
tbuf[0] = '-';
(void)strcpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ?
p + 1 : pwd->pw_shell);
if (setlogin(pwd->pw_name) < 0)
syslog(LOG_ERR, "setlogin() failure: %m");
/* Discard permissions last so can't get killed and drop core. */
if (rootlogin)
(void) setuid(0);
else
(void) setuid(pwd->pw_uid);
if (changepass) {
int res;
if ((res=system(_PATH_CHPASS)))
sleepexit(1);
}
execlp(pwd->pw_shell, tbuf, 0);
err(1, "%s", pwd->pw_shell);
}
#ifdef KERBEROS
#define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */
#else
#define NBUFSIZ (UT_NAMESIZE + 1)
#endif
void
getloginname()
{
int ch;
char *p;
static char nbuf[NBUFSIZ];
for (;;) {
(void)printf("login: ");
for (p = nbuf; (ch = getchar()) != '\n'; ) {
if (ch == EOF) {
badlogin(username);
exit(0);
}
if (p < nbuf + (NBUFSIZ - 1))
*p++ = ch;
}
if (p > nbuf)
if (nbuf[0] == '-')
(void)fprintf(stderr,
"login names may not start with '-'.\n");
else {
*p = '\0';
username = nbuf;
break;
}
}
}
int
rootterm(ttyn)
char *ttyn;
{
struct ttyent *t;
return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE);
}
jmp_buf motdinterrupt;
void
motd()
{
int fd, nchars;
sig_t oldint;
char tbuf[8192];
if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0)
return;
oldint = signal(SIGINT, sigint);
if (setjmp(motdinterrupt) == 0)
while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0)
(void)write(fileno(stdout), tbuf, nchars);
(void)signal(SIGINT, oldint);
(void)close(fd);
}
/* ARGSUSED */
void
sigint(signo)
int signo;
{
longjmp(motdinterrupt, 1);
}
/* ARGSUSED */
void
timedout(signo)
int signo;
{
(void)fprintf(stderr, "Login timed out after %d seconds\n", timeout);
exit(0);
}
void
checknologin()
{
int fd, nchars;
char tbuf[8192];
if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) {
while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0)
(void)write(fileno(stdout), tbuf, nchars);
sleepexit(0);
}
}
void
dolastlog(quiet)
int quiet;
{
struct lastlog ll;
int fd;
if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) {
(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
if (!quiet) {
if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) &&
ll.ll_time != 0) {
(void)printf("Last login: %.*s ",
24-5, (char *)ctime(&ll.ll_time));
if (*ll.ll_host != '\0')
(void)printf("from %.*s\n",
(int)sizeof(ll.ll_host),
ll.ll_host);
else
(void)printf("on %.*s\n",
(int)sizeof(ll.ll_line),
ll.ll_line);
}
(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
}
memset((void *)&ll, 0, sizeof(ll));
(void)time(&ll.ll_time);
(void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
if (hostname)
(void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host));
(void)write(fd, (char *)&ll, sizeof(ll));
(void)close(fd);
}
}
void
badlogin(name)
char *name;
{
if (failures == 0)
return;
if (hostname) {
syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s",
failures, failures > 1 ? "S" : "", hostname);
syslog(LOG_AUTHPRIV|LOG_NOTICE,
"%d LOGIN FAILURE%s FROM %s, %s",
failures, failures > 1 ? "S" : "", hostname, name);
} else {
syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s",
failures, failures > 1 ? "S" : "", tty);
syslog(LOG_AUTHPRIV|LOG_NOTICE,
"%d LOGIN FAILURE%s ON %s, %s",
failures, failures > 1 ? "S" : "", tty, name);
}
}
#undef UNKNOWN
#define UNKNOWN "su"
char *
stypeof(ttyid)
char *ttyid;
{
struct ttyent *t;
return (ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN);
}
void
sleepexit(eval)
int eval;
{
(void)sleep(5);
exit(eval);
}