4.3BSD-Reno/src/usr.bin/login/login.c
/*-
* 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: (1) source distributions retain this entire copyright notice and
* comment, and (2) distributions including binaries display the following
* acknowledgement: ``This product includes software developed by the
* University of California, Berkeley and its contributors'' in the
* documentation or other materials provided with the distribution and in
* all advertising materials mentioning features or use of this software.
* 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1980, 1987, 1988 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)login.c 5.63 (Berkeley) 6/29/90";
#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 <sgtty.h>
#include <utmp.h>
#include <signal.h>
#include <errno.h>
#include <ttyent.h>
#include <syslog.h>
#include <grp.h>
#include <pwd.h>
#include <setjmp.h>
#include <stdio.h>
#include <string.h>
#include <tzfile.h>
#include "pathnames.h"
#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.
*/
int timeout = 300;
#ifdef KERBEROS
int notickets = 1;
#endif
struct passwd *pwd;
int failures;
char term[64], *envinit[1], *hostname, *username, *tty;
main(argc, argv)
int argc;
char **argv;
{
extern int optind;
extern char *optarg, **environ;
struct timeval tp;
struct group *gr;
register int ch;
register char *p;
int ask, fflag, hflag, pflag, cnt, uid;
int quietlog, rval;
char *domain, *salt, *ttyn;
char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10];
char localhost[MAXHOSTNAMELEN];
char *ctime(), *ttyname(), *stypeof(), *crypt(), *getpass();
time_t time();
off_t lseek();
void timedout();
(void)signal(SIGALRM, timedout);
(void)alarm((u_int)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 = index(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) {
(void)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 = optarg;
break;
case 'p':
pflag = 1;
break;
case '?':
default:
if (!uid)
syslog(LOG_ERR, "invalid flag %c", ch);
(void)fprintf(stderr,
"usage: login [-fp] [username]\n");
exit(1);
}
argc -= optind;
argv += optind;
if (*argv) {
username = *argv;
if (strlen(username) > UT_NAMESIZE)
username[UT_NAMESIZE] = '\0';
ask = 0;
} else
ask = 1;
for (cnt = getdtablesize(); cnt > 2; cnt--)
close(cnt);
ttyn = ttyname(0);
if (ttyn == NULL || *ttyn == '\0') {
(void)sprintf(tname, "%s??", _PATH_TTY);
ttyn = tname;
}
if (tty = rindex(ttyn, '/'))
++tty;
else
tty = ttyn;
for (cnt = 0;; ask = 1) {
if (ask) {
fflag = 0;
getloginname();
}
/*
* 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 && (*pwd->pw_passwd == '\0' ||
fflag && (uid == 0 || uid == pwd->pw_uid)))
break;
fflag = 0;
/*
* If trying to log in as root, but with insecure terminal,
* refuse the login attempt.
*/
if (pwd && pwd->pw_uid == 0 && !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;
}
(void)setpriority(PRIO_PROCESS, 0, -4);
p = getpass("Password:");
if (pwd) {
#ifdef KERBEROS
rval = klogin(pwd, localhost, p);
if (rval == 1)
rval = strcmp(crypt(p, salt), pwd->pw_passwd);
#else
rval = strcmp(crypt(p, salt), pwd->pw_passwd);
#endif
}
bzero(p, strlen(p));
(void)setpriority(PRIO_PROCESS, 0, 0);
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);
/* paranoia... */
endpwent();
/* if user not super-user, check for disabled logins */
if (pwd->pw_uid)
checknologin();
if (chdir(pwd->pw_dir) < 0) {
(void)printf("No 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_expire));
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 */
{
struct utmp utmp;
bzero((void *)&utmp, sizeof(utmp));
(void)time(&utmp.ut_time);
strncpy(utmp.ut_name, username, sizeof(utmp.ut_name));
if (hostname)
strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
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);
(void)chmod(ttyn, 0620);
(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 preservation */
if (!pflag)
environ = envinit;
(void)setenv("HOME", pwd->pw_dir, 1);
(void)setenv("SHELL", pwd->pw_shell, 1);
if (term[0] == '\0')
strncpy(term, stypeof(tty), sizeof(term));
(void)setenv("TERM", term, 0);
(void)setenv("USER", pwd->pw_name, 1);
(void)setenv("PATH", _PATH_DEFPATH, 0);
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 (pwd->pw_uid == 0 && fflag == 0)
if (hostname)
syslog(LOG_NOTICE, "ROOT LOGIN ON %s FROM %s",
tty, hostname);
else
syslog(LOG_NOTICE, "ROOT LOGIN ON %s", tty);
#ifdef KERBEROS
if (!quietlog && notickets == 1)
(void)printf("Warning: no Kerberos tickets issued.\n");
#endif
if (!quietlog) {
struct stat st;
motd();
(void)sprintf(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] = '-';
strcpy(tbuf + 1, (p = rindex(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 */
(void)setuid(pwd->pw_uid);
execlp(pwd->pw_shell, tbuf, 0);
(void)fprintf(stderr, "login: no shell: %s.\n", strerror(errno));
exit(0);
}
getloginname()
{
register int ch;
register char *p;
static char nbuf[UT_NAMESIZE + 1];
for (;;) {
(void)printf("login: ");
for (p = nbuf; (ch = getchar()) != '\n'; ) {
if (ch == EOF) {
badlogin(username);
exit(0);
}
if (p < nbuf + UT_NAMESIZE)
*p++ = ch;
}
if (p > nbuf)
if (nbuf[0] == '-')
(void)fprintf(stderr,
"login names may not start with '-'.\n");
else {
*p = '\0';
username = nbuf;
break;
}
}
}
void
timedout()
{
(void)fprintf(stderr, "Login timed out after %d seconds\n", timeout);
exit(0);
}
rootterm(ttyn)
char *ttyn;
{
struct ttyent *t;
return((t = getttynam(ttyn)) && t->ty_status&TTY_SECURE);
}
jmp_buf motdinterrupt;
motd()
{
register int fd, nchars;
sig_t oldint;
int sigint();
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);
}
sigint()
{
longjmp(motdinterrupt, 1);
}
checknologin()
{
register 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);
}
}
dolastlog(quiet)
int quiet;
{
struct lastlog ll;
int fd;
char *ctime();
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",
sizeof(ll.ll_host), ll.ll_host);
else
(void)printf("on %.*s\n",
sizeof(ll.ll_line), ll.ll_line);
}
(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
}
bzero((void *)&ll, sizeof(ll));
(void)time(&ll.ll_time);
strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
if (hostname)
strncpy(ll.ll_host, hostname, sizeof(ll.ll_host));
(void)write(fd, (char *)&ll, sizeof(ll));
(void)close(fd);
}
}
badlogin(name)
char *name;
{
if (failures == 0)
return;
if (hostname)
syslog(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, %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);
}
sleepexit(eval)
int eval;
{
sleep((u_int)5);
exit(eval);
}