login.tproj/klogin.c

   1 /*
   2  * Copyright (c) 1999-2016 Apple 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
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  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(struct passwd *pw, char *instance, char *localhost, char *password)
  85 {
  86         int kerror;
  87         AUTH_DAT authdata;
  88         KTEXT_ST ticket;
  89         struct hostent *hp;
  90         unsigned long faddr;
  91         char realm[REALM_SZ], savehost[MAXHOSTNAMELEN];
  92         char tkt_location[MAXPATHLEN];
  93         char *krb_get_phost();
  94
  95         /*
  96          * Root logins don't use Kerberos.
  97          * If we have a realm, try getting a ticket-granting ticket
  98          * and using it to authenticate.  Otherwise, return
  99          * failure so that we can try the normal passwd file
 100          * for a password.  If that's ok, log the user in
 101          * without issuing any tickets.
 102          */
 103         if (strcmp(pw->pw_name, "root") == 0 ||
 104             krb_get_lrealm(realm, 0) != KSUCCESS)
 105                 return (1);
 106
 107         /*
 108          * get TGT for local realm
 109          * tickets are stored in a file named TKT_ROOT plus uid
 110          * except for user.root tickets.
 111          */
 112
 113         if (strcmp(instance, "root") != 0)
 114                 (void)sprintf(tkt_location, "%s%d", TKT_ROOT, pw->pw_uid);
 115         else {
 116                 (void)sprintf(tkt_location, "%s_root_%d", TKT_ROOT, pw->pw_uid);
 117                 krbtkfile_env = tkt_location;
 118         }
 119         (void)krb_set_tkt_string(tkt_location);
 120
 121         /*
 122          * Set real as well as effective ID to 0 for the moment,
 123          * to make the kerberos library do the right thing.
 124          */
 125         if (setuid(0) < 0) {
 126                 warnx("setuid");
 127                 return (1);
 128         }
 129         kerror = krb_get_pw_in_tkt(pw->pw_name, instance,
 130                     realm, INITIAL_TICKET, realm, DEFAULT_TKT_LIFE, password);
 131         /*
 132          * If we got a TGT, get a local "rcmd" ticket and check it so as to
 133          * ensure that we are not talking to a bogus Kerberos server.
 134          *
 135          * There are 2 cases where we still allow a login:
 136          *      1: the VERIFY_SERVICE doesn't exist in the KDC
 137          *      2: local host has no srvtab, as (hopefully) indicated by a
 138          *         return value of RD_AP_UNDEC from krb_rd_req().
 139          */
 140         if (kerror != INTK_OK) {
 141                 if (kerror != INTK_BADPW && kerror != KDC_PR_UNKNOWN) {
 142                         syslog(LOG_ERR, "Kerberos intkt error: %s",
 143                             krb_err_txt[kerror]);
 144                         dest_tkt();
 145                 }
 146                 return (1);
 147         }
 148
 149         if (chown(TKT_FILE, pw->pw_uid, pw->pw_gid) < 0)
 150                 syslog(LOG_ERR, "chown tkfile (%s): %m", TKT_FILE);
 151
 152         (void)strncpy(savehost, krb_get_phost(localhost), sizeof(savehost));
 153         savehost[sizeof(savehost)-1] = NULL;
 154
 155         /*
 156          * if the "VERIFY_SERVICE" doesn't exist in the KDC for this host,
 157          * still allow login with tickets, but log the error condition.
 158          */
 159
 160         kerror = krb_mk_req(&ticket, VERIFY_SERVICE, savehost, realm, 33);
 161         if (kerror == KDC_PR_UNKNOWN) {
 162                 syslog(LOG_NOTICE,
 163                     "warning: TGT not verified (%s); %s.%s not registered, or srvtab is wrong?",
 164                     krb_err_txt[kerror], VERIFY_SERVICE, savehost);
 165                 notickets = 0;
 166                 return (0);
 167         }
 168
 169         if (kerror != KSUCCESS) {
 170                 warnx("unable to use TGT: (%s)", krb_err_txt[kerror]);
 171                 syslog(LOG_NOTICE, "unable to use TGT: (%s)",
 172                     krb_err_txt[kerror]);
 173                 dest_tkt();
 174                 return (1);
 175         }
 176
 177         if (!(hp = gethostbyname(localhost))) {
 178                 syslog(LOG_ERR, "couldn't get local host address");
 179                 dest_tkt();
 180                 return (1);
 181         }
 182
 183         memmove((void *)&faddr, (void *)hp->h_addr, sizeof(faddr));
 184
 185         kerror = krb_rd_req(&ticket, VERIFY_SERVICE, savehost, faddr,
 186             &authdata, "");
 187
 188         if (kerror == KSUCCESS) {
 189                 notickets = 0;
 190                 return (0);
 191         }
 192
 193         /* undecipherable: probably didn't have a srvtab on the local host */
 194         if (kerror = RD_AP_UNDEC) {
 195                 syslog(LOG_NOTICE, "krb_rd_req: (%s)\n", krb_err_txt[kerror]);
 196                 dest_tkt();
 197                 return (1);
 198         }
 199         /* failed for some other reason */
 200         warnx("unable to verify %s ticket: (%s)", VERIFY_SERVICE,
 201             krb_err_txt[kerror]);
 202         syslog(LOG_NOTICE, "couldn't verify %s ticket: %s", VERIFY_SERVICE,
 203             krb_err_txt[kerror]);
 204         dest_tkt();
 205         return (1);
 206 }
 207 #endif