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 1.15 2003/11/21 11:57:02 djm 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 #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
  54         if (authctxt->krb5_ctx == NULL) {
  55                 problem = krb5_init_context(&authctxt->krb5_ctx);
  56                 if (problem)
  57                         return (problem);
  58 #ifdef KRB5_INIT_ETS
  59                 krb5_init_ets(authctxt->krb5_ctx);
  60 #endif
  61         }
  62         return (0);
  63 }
  64
  65 int
  66 auth_krb5_password(Authctxt *authctxt, const char *password)
  67 {
  68 #ifndef HEIMDAL
  69         krb5_creds creds;
  70         krb5_principal server;
  71         char ccname[40];
  72         int tmpfd;
  73         mode_t old_umask;
  74 #endif
  75         krb5_error_code problem;
  76         krb5_ccache ccache = NULL;
  77         int len;
  78
  79         if (!authctxt->valid)
  80                 return (0);
  81
  82         temporarily_use_uid(authctxt->pw);
  83
  84         problem = krb5_init(authctxt);
  85         if (problem)
  86                 goto out;
  87
  88         problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
  89                     &authctxt->krb5_user);
  90         if (problem)
  91                 goto out;
  92
  93 #ifdef HEIMDAL
  94         problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
  95         if (problem)
  96                 goto out;
  97
  98         problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
  99                 authctxt->krb5_user);
 100         if (problem)
 101                 goto out;
 102
 103         restore_uid();
 104
 105         problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
 106             ccache, password, 1, NULL);
 107
 108         temporarily_use_uid(authctxt->pw);
 109
 110         if (problem)
 111                 goto out;
 112
 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         old_umask = umask(0177);
 153         tmpfd = mkstemp(ccname + strlen("FILE:"));
 154         umask(old_umask);
 155         if (tmpfd == -1) {
 156                 logit("mkstemp(): %.100s", strerror(errno));
 157                 problem = errno;
 158                 goto out;
 159         }
 160
 161         if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
 162                 logit("fchmod(): %.100s", strerror(errno));
 163                 close(tmpfd);
 164                 problem = errno;
 165                 goto out;
 166         }
 167         close(tmpfd);
 168
 169         problem = krb5_cc_resolve(authctxt->krb5_ctx, ccname, &authctxt->krb5_fwd_ccache);
 170         if (problem)
 171                 goto out;
 172
 173         problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
 174                                      authctxt->krb5_user);
 175         if (problem)
 176                 goto out;
 177
 178         problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
 179                                  &creds);
 180         if (problem)
 181                 goto out;
 182 #endif
 183
 184         authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 185
 186         len = strlen(authctxt->krb5_ticket_file) + 6;
 187         authctxt->krb5_ccname = xmalloc(len);
 188         snprintf(authctxt->krb5_ccname, len, "FILE:%s",
 189             authctxt->krb5_ticket_file);
 190
 191 #ifdef USE_PAM
 192         if (options.use_pam)
 193                 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
 194 #endif
 195
 196  out:
 197         restore_uid();
 198
 199         if (problem) {
 200                 if (ccache)
 201                         krb5_cc_destroy(authctxt->krb5_ctx, ccache);
 202
 203                 if (authctxt->krb5_ctx != NULL && problem!=-1)
 204                         debug("Kerberos password authentication failed: %s",
 205                             krb5_get_err_text(authctxt->krb5_ctx, problem));
 206                 else
 207                         debug("Kerberos password authentication failed: %d",
 208                             problem);
 209
 210                 krb5_cleanup_proc(authctxt);
 211
 212                 if (options.kerberos_or_local_passwd)
 213                         return (-1);
 214                 else
 215                         return (0);
 216         }
 217         return (1);
 218 }
 219
 220 void
 221 krb5_cleanup_proc(Authctxt *authctxt)
 222 {
 223         debug("krb5_cleanup_proc called");
 224         if (authctxt->krb5_fwd_ccache) {
 225                 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
 226                 authctxt->krb5_fwd_ccache = NULL;
 227         }
 228         if (authctxt->krb5_user) {
 229                 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
 230                 authctxt->krb5_user = NULL;
 231         }
 232         if (authctxt->krb5_ctx) {
 233                 krb5_free_context(authctxt->krb5_ctx);
 234                 authctxt->krb5_ctx = NULL;
 235         }
 236 }
 237
 238 #endif /* KRB5 */