crypto/openssh/auth-krb5.c

   1 /*
   2  *    Kerberos v5 authentication and ticket-passing routines.
   3  *
   4  * $xFreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp$
   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 $");
  32 RCSID("$FreeBSD$");
  33
  34 #include "ssh.h"
  35 #include "ssh1.h"
  36 #include "packet.h"
  37 #include "xmalloc.h"
  38 #include "log.h"
  39 #include "servconf.h"
  40 #include "uidswap.h"
  41 #include "auth.h"
  42
  43 #ifdef KRB5
  44
  45 #include <krb5.h>
  46
  47 extern ServerOptions     options;
  48
  49 static int
  50 krb5_init(void *context)
  51 {
  52         Authctxt *authctxt = (Authctxt *)context;
  53         krb5_error_code problem;
  54         static int cleanup_registered = 0;
  55
  56         if (authctxt->krb5_ctx == NULL) {
  57                 problem = krb5_init_context(&authctxt->krb5_ctx);
  58                 if (problem)
  59                         return (problem);
  60                 krb5_init_ets(authctxt->krb5_ctx);
  61         }
  62         if (!cleanup_registered) {
  63                 fatal_add_cleanup(krb5_cleanup_proc, authctxt);
  64                 cleanup_registered = 1;
  65         }
  66         return (0);
  67 }
  68
  69 int
  70 auth_krb5_password(Authctxt *authctxt, const char *password)
  71 {
  72 #ifndef HEIMDAL
  73         krb5_creds creds;
  74         krb5_principal server;
  75         char ccname[40];
  76         int tmpfd;
  77 #endif
  78         krb5_error_code problem;
  79         krb5_ccache ccache = NULL;
  80
  81         if (authctxt->pw == NULL)
  82                 return (0);
  83
  84         temporarily_use_uid(authctxt->pw);
  85
  86         problem = krb5_init(authctxt);
  87         if (problem)
  88                 goto out;
  89
  90         problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
  91                     &authctxt->krb5_user);
  92         if (problem)
  93                 goto out;
  94
  95 #ifdef HEIMDAL
  96         problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
  97         if (problem)
  98                 goto out;
  99
 100         problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
 101                 authctxt->krb5_user);
 102         if (problem)
 103                 goto out;
 104
 105         restore_uid();
 106
 107         problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
 108             ccache, password, 1, NULL);
 109
 110         temporarily_use_uid(authctxt->pw);
 111
 112         if (problem)
 113                 goto out;
 114         problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
 115             &authctxt->krb5_fwd_ccache);
 116         if (problem)
 117                 goto out;
 118
 119         problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
 120             authctxt->krb5_fwd_ccache);
 121         krb5_cc_destroy(authctxt->krb5_ctx, ccache);
 122         ccache = NULL;
 123         if (problem)
 124                 goto out;
 125
 126 #else
 127         problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
 128             authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
 129         if (problem)
 130                 goto out;
 131
 132         problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
 133             KRB5_NT_SRV_HST, &server);
 134         if (problem)
 135                 goto out;
 136
 137         restore_uid();
 138         problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
 139             NULL, NULL, NULL);
 140         krb5_free_principal(authctxt->krb5_ctx, server);
 141         temporarily_use_uid(authctxt->pw);
 142         if (problem)
 143                 goto out;
 144
 145         if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
 146                           authctxt->pw->pw_name)) {
 147                 problem = -1;
 148                 goto out;
 149         }
 150
 151         snprintf(ccname,sizeof(ccname),"FILE:/tmp/krb5cc_%d_XXXXXX",geteuid());
 152
 153         if ((tmpfd = mkstemp(ccname+strlen("FILE:")))==-1) {
 154                 logit("mkstemp(): %.100s", strerror(errno));
 155                 problem = errno;
 156                 goto out;
 157         }
 158
 159         if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
 160                 logit("fchmod(): %.100s", strerror(errno));
 161                 close(tmpfd);
 162                 problem = errno;
 163                 goto out;
 164         }
 165         close(tmpfd);
 166
 167         problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &authctxt->krb5_fwd_ccache);
 168         if (problem)
 169                 goto out;
 170
 171         problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
 172                                      authctxt->krb5_user);
 173         if (problem)
 174                 goto out;
 175
 176         problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
 177                                  &creds);
 178         if (problem)
 179                 goto out;
 180 #endif
 181
 182         authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 183
 184  out:
 185         restore_uid();
 186
 187         if (problem) {
 188                 if (ccache)
 189                         krb5_cc_destroy(authctxt->krb5_ctx, ccache);
 190
 191                 if (authctxt->krb5_ctx != NULL && problem!=-1)
 192                         debug("Kerberos password authentication failed: %s",
 193                             krb5_get_err_text(authctxt->krb5_ctx, problem));
 194                 else
 195                         debug("Kerberos password authentication failed: %d",
 196                             problem);
 197
 198                 krb5_cleanup_proc(authctxt);
 199
 200                 if (options.kerberos_or_local_passwd)
 201                         return (-1);
 202                 else
 203                         return (0);
 204         }
 205         return (1);
 206 }
 207
 208 void
 209 krb5_cleanup_proc(void *context)
 210 {
 211         Authctxt *authctxt = (Authctxt *)context;
 212
 213         debug("krb5_cleanup_proc called");
 214         if (authctxt->krb5_fwd_ccache) {
 215                 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 216                 authctxt->krb5_fwd_ccache = NULL;
 217         }
 218         if (authctxt->krb5_user) {
 219                 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
 220                 authctxt->krb5_user = NULL;
 221         }
 222         if (authctxt->krb5_ctx) {
 223                 krb5_free_context(authctxt->krb5_ctx);
 224                 authctxt->krb5_ctx = NULL;
 225         }
 226 }
 227
 228 #endif /* KRB5 */