login.tproj/klogin.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.0 (the 'License').  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License."
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*-
  25  * Copyright (c) 1990, 1993, 1994
  26  *      The Regents of the University of California.  All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by the University of
  39  *      California, Berkeley and its contributors.
  40  * 4. Neither the name of the University nor the names of its contributors
  41  *    may be used to endorse or promote products derived from this software
  42  *    without specific prior written permission.
  43  *
  44  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  54  * SUCH DAMAGE.
  55  */
  56
  57 #ifdef KERBEROS
  58 #include <sys/param.h>
  59 #include <sys/syslog.h>
  60 #include <kerberosIV/des.h>
  61 #include <kerberosIV/krb.h>
  62
  63 #include <err.h>
  64 #include <netdb.h>
  65 #include <pwd.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69 #include <unistd.h>
  70
  71 #define INITIAL_TICKET  "krbtgt"
  72 #define VERIFY_SERVICE  "rcmd"
  73
  74 extern int notickets;
  75 extern char *krbtkfile_env;
  76
  77 /*
  78  * Attempt to log the user in using Kerberos authentication
  79  *
  80  * return 0 on success (will be logged in)
  81  *        1 if Kerberos failed (try local password in login)
  82  */
  83 int
  84 klogin(pw, instance, localhost, password)
  85         struct passwd *pw;
  86         char *instance, *localhost, *password;
  87 {
  88         int kerror;
  89         AUTH_DAT authdata;
  90         KTEXT_ST ticket;
  91         struct hostent *hp;
  92         unsigned long faddr;
  93         char realm[REALM_SZ], savehost[MAXHOSTNAMELEN];
  94         char tkt_location[MAXPATHLEN];
  95         char *krb_get_phost();
  96
  97         /*
  98          * Root logins don't use Kerberos.
  99          * If we have a realm, try getting a ticket-granting ticket
 100          * and using it to authenticate.  Otherwise, return
 101          * failure so that we can try the normal passwd file
 102          * for a password.  If that's ok, log the user in
 103          * without issuing any tickets.
 104          */
 105         if (strcmp(pw->pw_name, "root") == 0 ||
 106             krb_get_lrealm(realm, 0) != KSUCCESS)
 107                 return (1);
 108
 109         /*
 110          * get TGT for local realm
 111          * tickets are stored in a file named TKT_ROOT plus uid
 112          * except for user.root tickets.
 113          */
 114
 115         if (strcmp(instance, "root") != 0)
 116                 (void)sprintf(tkt_location, "%s%d", TKT_ROOT, pw->pw_uid);
 117         else {
 118                 (void)sprintf(tkt_location, "%s_root_%d", TKT_ROOT, pw->pw_uid);
 119                 krbtkfile_env = tkt_location;
 120         }
 121         (void)krb_set_tkt_string(tkt_location);
 122
 123         /*
 124          * Set real as well as effective ID to 0 for the moment,
 125          * to make the kerberos library do the right thing.
 126          */
 127         if (setuid(0) < 0) {
 128                 warnx("setuid");
 129                 return (1);
 130         }
 131         kerror = krb_get_pw_in_tkt(pw->pw_name, instance,
 132                     realm, INITIAL_TICKET, realm, DEFAULT_TKT_LIFE, password);
 133         /*
 134          * If we got a TGT, get a local "rcmd" ticket and check it so as to
 135          * ensure that we are not talking to a bogus Kerberos server.
 136          *
 137          * There are 2 cases where we still allow a login:
 138          *      1: the VERIFY_SERVICE doesn't exist in the KDC
 139          *      2: local host has no srvtab, as (hopefully) indicated by a
 140          *         return value of RD_AP_UNDEC from krb_rd_req().
 141          */
 142         if (kerror != INTK_OK) {
 143                 if (kerror != INTK_BADPW && kerror != KDC_PR_UNKNOWN) {
 144                         syslog(LOG_ERR, "Kerberos intkt error: %s",
 145                             krb_err_txt[kerror]);
 146                         dest_tkt();
 147                 }
 148                 return (1);
 149         }
 150
 151         if (chown(TKT_FILE, pw->pw_uid, pw->pw_gid) < 0)
 152                 syslog(LOG_ERR, "chown tkfile (%s): %m", TKT_FILE);
 153
 154         (void)strncpy(savehost, krb_get_phost(localhost), sizeof(savehost));
 155         savehost[sizeof(savehost)-1] = NULL;
 156
 157         /*
 158          * if the "VERIFY_SERVICE" doesn't exist in the KDC for this host,
 159          * still allow login with tickets, but log the error condition.
 160          */
 161
 162         kerror = krb_mk_req(&ticket, VERIFY_SERVICE, savehost, realm, 33);
 163         if (kerror == KDC_PR_UNKNOWN) {
 164                 syslog(LOG_NOTICE,
 165                     "warning: TGT not verified (%s); %s.%s not registered, or srvtab is wrong?",
 166                     krb_err_txt[kerror], VERIFY_SERVICE, savehost);
 167                 notickets = 0;
 168                 return (0);
 169         }
 170
 171         if (kerror != KSUCCESS) {
 172                 warnx("unable to use TGT: (%s)", krb_err_txt[kerror]);
 173                 syslog(LOG_NOTICE, "unable to use TGT: (%s)",
 174                     krb_err_txt[kerror]);
 175                 dest_tkt();
 176                 return (1);
 177         }
 178
 179         if (!(hp = gethostbyname(localhost))) {
 180                 syslog(LOG_ERR, "couldn't get local host address");
 181                 dest_tkt();
 182                 return (1);
 183         }
 184
 185         memmove((void *)&faddr, (void *)hp->h_addr, sizeof(faddr));
 186
 187         kerror = krb_rd_req(&ticket, VERIFY_SERVICE, savehost, faddr,
 188             &authdata, "");
 189
 190         if (kerror == KSUCCESS) {
 191                 notickets = 0;
 192                 return (0);
 193         }
 194
 195         /* undecipherable: probably didn't have a srvtab on the local host */
 196         if (kerror = RD_AP_UNDEC) {
 197                 syslog(LOG_NOTICE, "krb_rd_req: (%s)\n", krb_err_txt[kerror]);
 198                 dest_tkt();
 199                 return (1);
 200         }
 201         /* failed for some other reason */
 202         warnx("unable to verify %s ticket: (%s)", VERIFY_SERVICE,
 203             krb_err_txt[kerror]);
 204         syslog(LOG_NOTICE, "couldn't verify %s ticket: %s", VERIFY_SERVICE,
 205             krb_err_txt[kerror]);
 206         dest_tkt();
 207         return (1);
 208 }
 209 #endif