source4/kdc/kpasswd-service-heimdal.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Samba kpasswd implementation
   5
   6    Copyright (c) 2016      Andreas Schneider <asn@samba.org>
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "samba/service_task.h"
  24 #include "param/param.h"
  25 #include "auth/auth.h"
  26 #include "auth/gensec/gensec.h"
  27 #include "gensec_krb5_helpers.h"
  28 #include "kdc/kdc-server.h"
  29 #include "kdc/kpasswd_glue.h"
  30 #include "kdc/kpasswd-service.h"
  31 #include "kdc/kpasswd-helper.h"
  32
  33 #undef DBGC_CLASS
  34 #define DBGC_CLASS DBGC_KERBEROS
  35
  36 static krb5_error_code kpasswd_change_password(struct kdc_server *kdc,
  37                                                TALLOC_CTX *mem_ctx,
  38                                                const struct gensec_security *gensec_security,
  39                                                struct auth_session_info *session_info,
  40                                                DATA_BLOB *password,
  41                                                DATA_BLOB *kpasswd_reply,
  42                                                const char **error_string)
  43 {
  44         NTSTATUS status;
  45         NTSTATUS result = NT_STATUS_UNSUCCESSFUL;
  46         enum samPwdChangeReason reject_reason = SAM_PWD_CHANGE_NO_ERROR;
  47         const char *reject_string = NULL;
  48         struct samr_DomInfo1 *dominfo = NULL;
  49         bool ok;
  50         int ret;
  51
  52         /*
  53          * We're doing a password change (rather than a password set), so check
  54          * that we were given an initial ticket.
  55          */
  56         ret = gensec_krb5_initial_ticket(gensec_security);
  57         if (ret != 1) {
  58                 *error_string = "Expected an initial ticket";
  59                 return KRB5_KPASSWD_INITIAL_FLAG_NEEDED;
  60         }
  61
  62         status = samdb_kpasswd_change_password(mem_ctx,
  63                                                kdc->task->lp_ctx,
  64                                                kdc->task->event_ctx,
  65                                                session_info,
  66                                                password,
  67                                                &reject_reason,
  68                                                &dominfo,
  69                                                &reject_string,
  70                                                &result);
  71         if (!NT_STATUS_IS_OK(status)) {
  72                 ok = kpasswd_make_error_reply(mem_ctx,
  73                                               KRB5_KPASSWD_ACCESSDENIED,
  74                                               reject_string,
  75                                               kpasswd_reply);
  76                 if (!ok) {
  77                         *error_string = "Failed to create reply";
  78                         return KRB5_KPASSWD_HARDERROR;
  79                 }
  80                 /* We want to send an an authenticated packet. */
  81                 return 0;
  82         }
  83
  84         ok = kpasswd_make_pwchange_reply(mem_ctx,
  85                                          result,
  86                                          reject_reason,
  87                                          dominfo,
  88                                          kpasswd_reply);
  89         if (!ok) {
  90                 *error_string = "Failed to create reply";
  91                 return KRB5_KPASSWD_HARDERROR;
  92         }
  93
  94         return 0;
  95 }
  96
  97 static krb5_error_code kpasswd_set_password(struct kdc_server *kdc,
  98                                             TALLOC_CTX *mem_ctx,
  99                                             const struct gensec_security *gensec_security,
 100                                             struct auth_session_info *session_info,
 101                                             DATA_BLOB *decoded_data,
 102                                             DATA_BLOB *kpasswd_reply,
 103                                             const char **error_string)
 104 {
 105         krb5_context context = kdc->smb_krb5_context->krb5_context;
 106         krb5_error_code code;
 107         krb5_principal target_principal;
 108         ChangePasswdDataMS chpw = {};
 109         size_t chpw_len = 0;
 110         DATA_BLOB password = data_blob_null;
 111         enum samPwdChangeReason reject_reason = SAM_PWD_CHANGE_NO_ERROR;
 112         struct samr_DomInfo1 *dominfo = NULL;
 113         char *target_principal_string = NULL;
 114         bool is_service_principal = false;
 115         NTSTATUS status;
 116         bool ok;
 117
 118         code = decode_ChangePasswdDataMS(decoded_data->data,
 119                                          decoded_data->length,
 120                                          &chpw,
 121                                          &chpw_len);
 122         if (code != 0) {
 123                 DBG_WARNING("decode_ChangePasswdDataMS failed\n");
 124                 ok = kpasswd_make_error_reply(mem_ctx,
 125                                               KRB5_KPASSWD_MALFORMED,
 126                                               "Failed to decode packet",
 127                                               kpasswd_reply);
 128                 if (!ok) {
 129                         *error_string = "Failed to create reply";
 130                         return KRB5_KPASSWD_HARDERROR;
 131                 }
 132                 return 0;
 133         }
 134
 135         ok = convert_string_talloc_handle(mem_ctx,
 136                                           lpcfg_iconv_handle(kdc->task->lp_ctx),
 137                                           CH_UTF8,
 138                                           CH_UTF16,
 139                                           chpw.newpasswd.data,
 140                                           chpw.newpasswd.length,
 141                                           &password.data,
 142                                           &password.length);
 143         if (!ok) {
 144                 free_ChangePasswdDataMS(&chpw);
 145                 DBG_WARNING("String conversion failed\n");
 146                 *error_string = "String conversion failed";
 147                 return KRB5_KPASSWD_HARDERROR;
 148         }
 149
 150         if ((chpw.targname != NULL && chpw.targrealm == NULL) ||
 151             (chpw.targname == NULL && chpw.targrealm != NULL)) {
 152                 free_ChangePasswdDataMS(&chpw);
 153                 ok = kpasswd_make_error_reply(mem_ctx,
 154                                               KRB5_KPASSWD_MALFORMED,
 155                                               "Realm and principal must be "
 156                                               "both present, or neither present",
 157                                               kpasswd_reply);
 158                 if (!ok) {
 159                         *error_string = "Failed to create reply";
 160                         return KRB5_KPASSWD_HARDERROR;
 161                 }
 162                 return 0;
 163         }
 164
 165         if (chpw.targname == NULL || chpw.targrealm == NULL) {
 166                 free_ChangePasswdDataMS(&chpw);
 167                 return kpasswd_change_password(kdc,
 168                                                mem_ctx,
 169                                                gensec_security,
 170                                                session_info,
 171                                                &password,
 172                                                kpasswd_reply,
 173                                                error_string);
 174         }
 175         code = krb5_build_principal_ext(context,
 176                                         &target_principal,
 177                                         strlen(*chpw.targrealm),
 178                                         *chpw.targrealm,
 179                                         0);
 180         if (code != 0) {
 181                 free_ChangePasswdDataMS(&chpw);
 182                 return kpasswd_make_error_reply(mem_ctx,
 183                                                 KRB5_KPASSWD_MALFORMED,
 184                                                 "Failed to parse principal",
 185                                                 kpasswd_reply);
 186         }
 187         code = copy_PrincipalName(chpw.targname,
 188                                   &target_principal->name);
 189         free_ChangePasswdDataMS(&chpw);
 190         if (code != 0) {
 191                 krb5_free_principal(context, target_principal);
 192                 return kpasswd_make_error_reply(mem_ctx,
 193                                                 KRB5_KPASSWD_MALFORMED,
 194                                                 "Failed to parse principal",
 195                                                 kpasswd_reply);
 196         }
 197
 198         if (target_principal->name.name_string.len >= 2) {
 199                 is_service_principal = true;
 200
 201                 code = krb5_unparse_name_short(context,
 202                                                target_principal,
 203                                                &target_principal_string);
 204         } else {
 205                 code = krb5_unparse_name(context,
 206                                          target_principal,
 207                                          &target_principal_string);
 208         }
 209         krb5_free_principal(context, target_principal);
 210         if (code != 0) {
 211                 ok = kpasswd_make_error_reply(mem_ctx,
 212                                               KRB5_KPASSWD_MALFORMED,
 213                                               "Failed to parse principal",
 214                                               kpasswd_reply);
 215                 if (!ok) {
 216                         krb5_xfree(target_principal_string);
 217                         *error_string = "Failed to create reply";
 218                         return KRB5_KPASSWD_HARDERROR;
 219                 }
 220         }
 221
 222         status = kpasswd_samdb_set_password(mem_ctx,
 223                                             kdc->task->event_ctx,
 224                                             kdc->task->lp_ctx,
 225                                             session_info,
 226                                             is_service_principal,
 227                                             target_principal_string,
 228                                             &password,
 229                                             &reject_reason,
 230                                             &dominfo);
 231         krb5_xfree(target_principal_string);
 232         if (!NT_STATUS_IS_OK(status)) {
 233                 DBG_ERR("kpasswd_samdb_set_password failed - %s\n",
 234                         nt_errstr(status));
 235         }
 236
 237         ok = kpasswd_make_pwchange_reply(mem_ctx,
 238                                          status,
 239                                          reject_reason,
 240                                          dominfo,
 241                                          kpasswd_reply);
 242         if (!ok) {
 243                 *error_string = "Failed to create reply";
 244                 return KRB5_KPASSWD_HARDERROR;
 245         }
 246
 247         return 0;
 248 }
 249
 250 krb5_error_code kpasswd_handle_request(struct kdc_server *kdc,
 251                                        TALLOC_CTX *mem_ctx,
 252                                        struct gensec_security *gensec_security,
 253                                        uint16_t verno,
 254                                        DATA_BLOB *decoded_data,
 255                                        DATA_BLOB *kpasswd_reply,
 256                                        const char **error_string)
 257 {
 258         struct auth_session_info *session_info;
 259         NTSTATUS status;
 260         krb5_error_code code;
 261
 262         status = gensec_session_info(gensec_security,
 263                                      mem_ctx,
 264                                      &session_info);
 265         if (!NT_STATUS_IS_OK(status)) {
 266                 *error_string = talloc_asprintf(mem_ctx,
 267                                                 "gensec_session_info failed - %s",
 268                                                 nt_errstr(status));
 269                 return KRB5_KPASSWD_HARDERROR;
 270         }
 271
 272         /*
 273          * Since the kpasswd service shares its keys with the krbtgt, we might
 274          * have received a TGT rather than a kpasswd ticket. We need to check
 275          * the ticket type to ensure that TGTs cannot be misused in this manner.
 276          */
 277         code = kpasswd_check_non_tgt(session_info,
 278                                      error_string);
 279         if (code != 0) {
 280                 DBG_WARNING("%s\n", *error_string);
 281                 return code;
 282         }
 283
 284         switch(verno) {
 285         case KRB5_KPASSWD_VERS_CHANGEPW: {
 286                 DATA_BLOB password = data_blob_null;
 287                 bool ok;
 288
 289                 ok = convert_string_talloc_handle(mem_ctx,
 290                                                   lpcfg_iconv_handle(kdc->task->lp_ctx),
 291                                                   CH_UTF8,
 292                                                   CH_UTF16,
 293                                                   decoded_data->data,
 294                                                   decoded_data->length,
 295                                                   &password.data,
 296                                                   &password.length);
 297                 if (!ok) {
 298                         *error_string = "String conversion failed!";
 299                         DBG_WARNING("%s\n", *error_string);
 300                         return KRB5_KPASSWD_HARDERROR;
 301                 }
 302
 303                 return kpasswd_change_password(kdc,
 304                                                mem_ctx,
 305                                                gensec_security,
 306                                                session_info,
 307                                                &password,
 308                                                kpasswd_reply,
 309                                                error_string);
 310         }
 311         case KRB5_KPASSWD_VERS_SETPW: {
 312                 return kpasswd_set_password(kdc,
 313                                             mem_ctx,
 314                                             gensec_security,
 315                                             session_info,
 316                                             decoded_data,
 317                                             kpasswd_reply,
 318                                             error_string);
 319         }
 320         default:
 321                 *error_string = talloc_asprintf(mem_ctx,
 322                                                 "Protocol version %u not supported",
 323                                                 verno);
 324                 return KRB5_KPASSWD_BAD_VERSION;
 325         }
 326
 327         return 0;
 328 }