NetBSD/usr.bin/login/klogin.c

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/* $NetBSD: klogin.c,v 1.13 1997/10/19 19:11:56 mycroft Exp $ */
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/*-
* Copyright (c) 1990, 1993, 1994
* The Regents of the University of California. All rights reserved.
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*
* 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.
*/
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#include <sys/cdefs.h>
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#ifndef lint
#if 0
static char sccsid[] = "@(#)klogin.c 8.3 (Berkeley) 4/2/94";
#endif
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__RCSID("$NetBSD: klogin.c,v 1.13 1997/10/19 19:11:56 mycroft Exp $");
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#endif /* not lint */
#ifdef KERBEROS
#include <sys/param.h>
#include <sys/syslog.h>
#include <kerberosIV/des.h>
#include <kerberosIV/krb.h>
#include <err.h>
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#include <netdb.h>
#include <pwd.h>
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#include <stdio.h>
#include <stdlib.h>
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#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
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#define INITIAL_TICKET "krbtgt"
#define VERIFY_SERVICE "rcmd"
extern int notickets;
extern char *krbtkfile_env;
extern char *tty;
static char tkt_location[MAXPATHLEN]; /* a pointer to this is returned... */
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int klogin __P((struct passwd *, char *, char *, char *));
void kdestroy __P((void));
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/*
* Attempt to log the user in using Kerberos authentication
*
* return 0 on success (will be logged in)
* 1 if Kerberos failed (try local password in login)
*/
int
klogin(pw, instance, localhost, password)
struct passwd *pw;
char *instance, *localhost, *password;
{
int kerror;
AUTH_DAT authdata;
KTEXT_ST ticket;
struct hostent *hp;
unsigned long faddr;
char realm[REALM_SZ], savehost[MAXHOSTNAMELEN];
/*
* Root logins don't use Kerberos.
* If we have a realm, try getting a ticket-granting ticket
* and using it to authenticate. Otherwise, return
* failure so that we can try the normal passwd file
* for a password. If that's ok, log the user in
* without issuing any tickets.
*/
if (strcmp(pw->pw_name, "root") == 0 ||
krb_get_lrealm(realm, 0) != KSUCCESS)
return (1);
/*
* get TGT for local realm
* tickets are stored in a file named TKT_ROOT plus uid plus tty
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* except for user.root tickets.
*/
if (strcmp(instance, "root") != 0)
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(void)snprintf(tkt_location, sizeof tkt_location, "%s%d.%s",
TKT_ROOT, pw->pw_uid, tty);
else
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(void)snprintf(tkt_location, sizeof tkt_location,
"%s_root_%d.%s", TKT_ROOT, pw->pw_uid, tty);
krbtkfile_env = tkt_location;
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(void)krb_set_tkt_string(tkt_location);
/*
* Set real as well as effective ID to 0 for the moment,
* to make the kerberos library do the right thing.
*/
if (setuid(0) < 0) {
warnx("setuid");
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return (1);
}
kerror = krb_get_pw_in_tkt(pw->pw_name, instance,
realm, INITIAL_TICKET, realm, DEFAULT_TKT_LIFE, password);
/*
* If we got a TGT, get a local "rcmd" ticket and check it so as to
* ensure that we are not talking to a bogus Kerberos server.
*
* There are 2 cases where we still allow a login:
* 1: the VERIFY_SERVICE doesn't exist in the KDC
* 2: local host has no srvtab, as (hopefully) indicated by a
* return value of RD_AP_UNDEC from krb_rd_req().
*/
if (kerror != INTK_OK) {
if (kerror != INTK_BADPW && kerror != KDC_PR_UNKNOWN) {
syslog(LOG_ERR, "Kerberos intkt error: %s",
krb_err_txt[kerror]);
dest_tkt();
}
return (1);
}
if (chown(TKT_FILE, pw->pw_uid, pw->pw_gid) < 0)
syslog(LOG_ERR, "chown tkfile (%s): %m", TKT_FILE);
(void)strncpy(savehost, krb_get_phost(localhost), sizeof(savehost));
savehost[sizeof(savehost)-1] = NULL;
/*
* if the "VERIFY_SERVICE" doesn't exist in the KDC for this host,
* still allow login with tickets, but log the error condition.
*/
kerror = krb_mk_req(&ticket, VERIFY_SERVICE, savehost, realm, 33);
if (kerror == KDC_PR_UNKNOWN) {
syslog(LOG_NOTICE,
"warning: TGT not verified (%s); %s.%s not registered, or srvtab is wrong?",
krb_err_txt[kerror], VERIFY_SERVICE, savehost);
notickets = 0;
/*
* but for security, don't allow root instances in under
* this condition!
*/
if (strcmp(instance, "root") == 0) {
syslog(LOG_ERR, "Kerberos %s root instance login refused\n",
pw->pw_name);
dest_tkt();
return (1);
}
return (0);
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}
if (kerror != KSUCCESS) {
warnx("unable to use TGT: (%s)", krb_err_txt[kerror]);
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syslog(LOG_NOTICE, "unable to use TGT: (%s)",
krb_err_txt[kerror]);
dest_tkt();
return (1);
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}
if (!(hp = gethostbyname(localhost))) {
syslog(LOG_ERR, "couldn't get local host address");
dest_tkt();
return (1);
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}
memmove((void *)&faddr, (void *)hp->h_addr, sizeof(faddr));
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kerror = krb_rd_req(&ticket, VERIFY_SERVICE, savehost, faddr,
&authdata, "");
if (kerror == KSUCCESS) {
notickets = 0;
return (0);
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}
/* undecipherable: probably didn't have a srvtab on the local host */
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if (kerror == RD_AP_UNDEC) {
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syslog(LOG_NOTICE, "krb_rd_req: (%s)\n", krb_err_txt[kerror]);
dest_tkt();
return (1);
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}
/* failed for some other reason */
warnx("unable to verify %s ticket: (%s)", VERIFY_SERVICE,
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krb_err_txt[kerror]);
syslog(LOG_NOTICE, "couldn't verify %s ticket: %s", VERIFY_SERVICE,
krb_err_txt[kerror]);
dest_tkt();
return (1);
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}
void
kdestroy()
{
char *file = krbtkfile_env;
int i, fd;
extern int errno;
struct stat statb;
char buf[BUFSIZ];
#ifdef TKT_SHMEM
char shmidname[MAXPATHLEN];
#endif /* TKT_SHMEM */
if (krbtkfile_env == NULL)
return;
errno = 0;
if (lstat(file, &statb) < 0)
goto out;
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if (!S_ISREG(statb.st_mode)
#ifdef notdef
|| statb.st_mode & 077
#endif
)
goto out;
if ((fd = open(file, O_RDWR, 0)) < 0)
goto out;
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memset(buf, 0, BUFSIZ);
for (i = 0; i < statb.st_size; i += BUFSIZ)
if (write(fd, buf, BUFSIZ) != BUFSIZ) {
(void) fsync(fd);
(void) close(fd);
goto out;
}
(void) fsync(fd);
(void) close(fd);
(void) unlink(file);
out:
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if (errno != 0)
return;
#ifdef TKT_SHMEM
/*
* handle the shared memory case
*/
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/* 5 == 4 (".shm") + 1 */
(void)strncpy(shmidname, file, sizeof(shmidname) - 5);
(void)strcat(shmidname, ".shm"); /* XXX strcat is safe */
if (krb_shm_dest(shmidname) != KSUCCESS)
return;
#endif /* TKT_SHMEM */
return;
}
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#endif