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NetBSD/usr.bin/login/login.c

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/* $NetBSD: login.c,v 1.17 1997/02/11 08:15:10 mrg Exp $ */
/*-
* 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
#if 0
static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94";
#endif
static char rcsid[] = "$NetBSD: login.c,v 1.17 1997/02/11 08:15:10 mrg Exp $";
#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>
#include <util.h>
#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));
int pwcheck __P((char *, char *, char *, char *));
#if defined(KERBEROS) || defined(KERBEROS5)
int klogin __P((struct passwd *, char *, char *, char *));
void kdestroy __P((void));
void dofork __P((void));
#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;
#if defined(KERBEROS) || defined(KERBEROS5)
int notickets = 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;
uid_t uid;
char *domain, *p, *salt, *ttyn;
char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10];
char localhost[MAXHOSTNAMELEN];
(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
*/
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;
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 defined(KERBEROS) || defined(KERBEROS5)
kdestroy();
#endif
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
#ifdef KERBEROS5
if ((instance = strchr(username, '/')) != NULL) {
if (strncmp(instance, "/root", 5) == 0)
rootlogin = 1;
*instance++ = '\0';
} else
instance = "";
#endif
if (strlen(username) > MAXLOGNAME)
username[MAXLOGNAME] = '\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)strncpy(tbuf, username, sizeof(tbuf) - 1);
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);
p = getpass("Password:");
if (pwd) {
#if defined(KERBEROS) || defined(KERBEROS5)
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) {
if (pwd->pw_uid != 0)
rootlogin = 0;
rval = pwcheck(username, p, salt, pwd->pw_passwd);
}
#else
rval = pwcheck(username, p, salt, 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.
*/
#if defined(KERBEROS) || defined(KERBEROS5)
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);
if (pwd->pw_change)
if (tp.tv_sec >= pwd->pw_change) {
(void)printf("Sorry -- your password has expired.\n");
sleepexit(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);
(void)chown(ttyn, pwd->pw_uid,
(gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid);
if (ttyaction(ttyn, "login", pwd->pw_name))
(void)printf("Warning: ttyaction failed.\n");
#if defined(KERBEROS) || defined(KERBEROS5)
/* Fork so that we can call kdestroy */
if (krbtkfile_env)
dofork();
#endif
(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
#ifdef KERBEROS5
if (krbtkfile_env)
(void)setenv("KRB5CCNAME", 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);
#if defined(KERBEROS) || defined(KERBEROS5)
if (!quietlog && notickets == 1)
(void)printf("Warning: no Kerberos tickets issued.\n");
#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 " : "");
}
(void)signal(SIGALRM, SIG_DFL);
(void)signal(SIGQUIT, SIG_DFL);
(void)signal(SIGINT, SIG_DFL);
(void)signal(SIGTSTP, SIG_IGN);
tbuf[0] = '-';
(void)strncpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ?
p + 1 : pwd->pw_shell, sizeof(tbuf) - 2);
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);
execlp(pwd->pw_shell, tbuf, 0);
err(1, "%s", pwd->pw_shell);
}
int
pwcheck(user, p, salt, passwd)
char *user, *p, *salt, *passwd;
{
#ifdef SKEY
if (strcasecmp(p, "s/key") == 0)
if (skey_haskey(user))
return 1;
else
return skey_authenticate(user);
#endif
return strcmp(crypt(p, salt), passwd);
}
#if defined(KERBEROS) || defined(KERBEROS5)
#define NBUFSIZ (MAXLOGNAME + 1 + 5) /* .root suffix */
#else
#define NBUFSIZ (MAXLOGNAME + 1)
#endif
#if defined(KERBEROS) || defined(KERBEROS5)
/*
* This routine handles cleanup stuff, and the like.
* It exists only in the child process.
*/
#include <sys/wait.h>
void
dofork()
{
int child;
if (!(child = fork()))
return; /* Child process */
/* Setup stuff? This would be things we could do in parallel with login */
(void) chdir("/"); /* Let's not keep the fs busy... */
/* If we're the parent, watch the child until it dies */
while (wait(0) != child)
;
/* Cleanup stuff */
/* Run kdestroy to destroy tickets */
kdestroy();
/* Leave */
exit(0);
}
#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);
}
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