auth-krb5.c

   1 /*
   2  *    Kerberos v5 authentication and ticket-passing routines.
   3  *
   4  * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
   5  */
   6 /*
   7  * Copyright (c) 2002 Daniel Kouril.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include "includes.h"
  31 RCSID("$OpenBSD: auth-krb5.c,v 1.12 2003/08/28 12:54:34 markus Exp $");
  32
  33 #include "ssh.h"
  34 #include "ssh1.h"
  35 #include "packet.h"
  36 #include "xmalloc.h"
  37 #include "log.h"
  38 #include "servconf.h"
  39 #include "uidswap.h"
  40 #include "auth.h"
  41
  42 #ifdef KRB5
  43
  44 #include <krb5.h>
  45
  46 extern ServerOptions     options;
  47
  48 static int
  49 krb5_init(void *context)
  50 {
  51         Authctxt *authctxt = (Authctxt *)context;
  52         krb5_error_code problem;
  53         static int cleanup_registered = 0;
  54
  55         if (authctxt->krb5_ctx == NULL) {
  56                 problem = krb5_init_context(&authctxt->krb5_ctx);
  57                 if (problem)
  58                         return (problem);
  59                 krb5_init_ets(authctxt->krb5_ctx);
  60         }
  61         if (!cleanup_registered) {
  62                 fatal_add_cleanup(krb5_cleanup_proc, authctxt);
  63                 cleanup_registered = 1;
  64         }
  65         return (0);
  66 }
  67
  68 int
  69 auth_krb5_password(Authctxt *authctxt, const char *password)
  70 {
  71 #ifndef HEIMDAL
  72         krb5_creds creds;
  73         krb5_principal server;
  74         char ccname[40];
  75         int tmpfd;
  76 #endif
  77         krb5_error_code problem;
  78         krb5_ccache ccache = NULL;
  79
  80         if (authctxt->pw == NULL)
  81                 return (0);
  82
  83         temporarily_use_uid(authctxt->pw);
  84
  85         problem = krb5_init(authctxt);
  86         if (problem)
  87                 goto out;
  88
  89         problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
  90                     &authctxt->krb5_user);
  91         if (problem)
  92                 goto out;
  93
  94 #ifdef HEIMDAL
  95         problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
  96         if (problem)
  97                 goto out;
  98
  99         problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
 100                 authctxt->krb5_user);
 101         if (problem)
 102                 goto out;
 103
 104         restore_uid();
 105
 106         problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
 107             ccache, password, 1, NULL);
 108
 109         temporarily_use_uid(authctxt->pw);
 110
 111         if (problem)
 112                 goto out;
 113         problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
 114             &authctxt->krb5_fwd_ccache);
 115         if (problem)
 116                 goto out;
 117
 118         problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
 119             authctxt->krb5_fwd_ccache);
 120         krb5_cc_destroy(authctxt->krb5_ctx, ccache);
 121         ccache = NULL;
 122         if (problem)
 123                 goto out;
 124
 125 #else
 126         problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
 127             authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
 128         if (problem)
 129                 goto out;
 130
 131         problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
 132             KRB5_NT_SRV_HST, &server);
 133         if (problem)
 134                 goto out;
 135
 136         restore_uid();
 137         problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
 138             NULL, NULL, NULL);
 139         krb5_free_principal(authctxt->krb5_ctx, server);
 140         temporarily_use_uid(authctxt->pw);
 141         if (problem)
 142                 goto out;
 143
 144         if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
 145                           authctxt->pw->pw_name)) {
 146                 problem = -1;
 147                 goto out;
 148         }
 149
 150         snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid());
 151
 152         if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) {
 153                 logit("mkstemp(): %.100s", strerror(errno));
 154                 problem = errno;
 155                 goto out;
 156         }
 157
 158         if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
 159                 logit("fchmod(): %.100s", strerror(errno));
 160                 close(tmpfd);
 161                 problem = errno;
 162                 goto out;
 163         }
 164         close(tmpfd);
 165
 166         problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &authctxt->krb5_fwd_ccache);
 167         if (problem)
 168                 goto out;
 169
 170         problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
 171                                      authctxt->krb5_user);
 172         if (problem)
 173                 goto out;
 174
 175         problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
 176                                  &creds);
 177         if (problem)
 178                 goto out;
 179 #endif
 180
 181         authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 182
 183  out:
 184         restore_uid();
 185
 186         if (problem) {
 187                 if (ccache)
 188                         krb5_cc_destroy(authctxt->krb5_ctx, ccache);
 189
 190                 if (authctxt->krb5_ctx != NULL && problem!=-1)
 191                         debug("Kerberos password authentication failed: %s",
 192                             krb5_get_err_text(authctxt->krb5_ctx, problem));
 193                 else
 194                         debug("Kerberos password authentication failed: %d",
 195                             problem);
 196
 197                 krb5_cleanup_proc(authctxt);
 198
 199                 if (options.kerberos_or_local_passwd)
 200                         return (-1);
 201                 else
 202                         return (0);
 203         }
 204         return (1);
 205 }
 206
 207 void
 208 krb5_cleanup_proc(void *context)
 209 {
 210         Authctxt *authctxt = (Authctxt *)context;
 211
 212         debug("krb5_cleanup_proc called");
 213         if (authctxt->krb5_fwd_ccache) {
 214                 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 215                 authctxt->krb5_fwd_ccache = NULL;
 216         }
 217         if (authctxt->krb5_user) {
 218                 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
 219                 authctxt->krb5_user = NULL;
 220         }
 221         if (authctxt->krb5_ctx) {
 222                 krb5_free_context(authctxt->krb5_ctx);
 223                 authctxt->krb5_ctx = NULL;
 224         }
 225 }
 226
 227 #endif /* KRB5 */