source4/kdc/kpasswdd.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    kpasswd Server implementation
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
   7    Copyright (C) Andrew Tridgell        2005
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "smbd/service_task.h"
  25 #include "lib/events/events.h"
  26 #include "lib/socket/socket.h"
  27 #include "lib/tsocket/tsocket.h"
  28 #include "system/network.h"
  29 #include "../lib/util/dlinklist.h"
  30 #include "lib/ldb/include/ldb.h"
  31 #include "auth/gensec/gensec.h"
  32 #include "auth/credentials/credentials.h"
  33 #include "auth/credentials/credentials_krb5.h"
  34 #include "auth/auth.h"
  35 #include "dsdb/samdb/samdb.h"
  36 #include "../lib/util/util_ldb.h"
  37 #include "rpc_server/dcerpc_server.h"
  38 #include "rpc_server/samr/proto.h"
  39 #include "libcli/security/security.h"
  40 #include "param/param.h"
  41 #include "kdc/kdc-glue.h"
  42
  43 /* Return true if there is a valid error packet formed in the error_blob */
  44 static bool kpasswdd_make_error_reply(struct kdc_server *kdc,
  45                                      TALLOC_CTX *mem_ctx,
  46                                      uint16_t result_code,
  47                                      const char *error_string,
  48                                      DATA_BLOB *error_blob)
  49 {
  50         char *error_string_utf8;
  51         size_t len;
  52
  53         DEBUG(result_code ? 3 : 10, ("kpasswdd: %s\n", error_string));
  54
  55         if (!push_utf8_talloc(mem_ctx, &error_string_utf8, error_string, &len)) {
  56                 return false;
  57         }
  58
  59         *error_blob = data_blob_talloc(mem_ctx, NULL, 2 + len + 1);
  60         if (!error_blob->data) {
  61                 return false;
  62         }
  63         RSSVAL(error_blob->data, 0, result_code);
  64         memcpy(error_blob->data + 2, error_string_utf8, len + 1);
  65         return true;
  66 }
  67
  68 /* Return true if there is a valid error packet formed in the error_blob */
  69 static bool kpasswdd_make_unauth_error_reply(struct kdc_server *kdc,
  70                                             TALLOC_CTX *mem_ctx,
  71                                             uint16_t result_code,
  72                                             const char *error_string,
  73                                             DATA_BLOB *error_blob)
  74 {
  75         bool ret;
  76         int kret;
  77         DATA_BLOB error_bytes;
  78         krb5_data k5_error_bytes, k5_error_blob;
  79         ret = kpasswdd_make_error_reply(kdc, mem_ctx, result_code, error_string,
  80                                        &error_bytes);
  81         if (!ret) {
  82                 return false;
  83         }
  84         k5_error_bytes.data = error_bytes.data;
  85         k5_error_bytes.length = error_bytes.length;
  86         kret = krb5_mk_error(kdc->smb_krb5_context->krb5_context,
  87                              result_code, NULL, &k5_error_bytes,
  88                              NULL, NULL, NULL, NULL, &k5_error_blob);
  89         if (kret) {
  90                 return false;
  91         }
  92         *error_blob = data_blob_talloc(mem_ctx, k5_error_blob.data, k5_error_blob.length);
  93         krb5_data_free(&k5_error_blob);
  94         if (!error_blob->data) {
  95                 return false;
  96         }
  97         return true;
  98 }
  99
 100 static bool kpasswd_make_pwchange_reply(struct kdc_server *kdc,
 101                                         TALLOC_CTX *mem_ctx,
 102                                         NTSTATUS status,
 103                                         enum samPwdChangeReason reject_reason,
 104                                         struct samr_DomInfo1 *dominfo,
 105                                         DATA_BLOB *error_blob)
 106 {
 107         if (NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_USER)) {
 108                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 109                                                 KRB5_KPASSWD_ACCESSDENIED,
 110                                                 "No such user when changing password",
 111                                                 error_blob);
 112         }
 113         if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
 114                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 115                                                 KRB5_KPASSWD_ACCESSDENIED,
 116                                                 "Not permitted to change password",
 117                                                 error_blob);
 118         }
 119         if (dominfo && NT_STATUS_EQUAL(status, NT_STATUS_PASSWORD_RESTRICTION)) {
 120                 const char *reject_string;
 121                 switch (reject_reason) {
 122                 case SAM_PWD_CHANGE_PASSWORD_TOO_SHORT:
 123                         reject_string = talloc_asprintf(mem_ctx, "Password too short, password must be at least %d characters long",
 124                                                         dominfo->min_password_length);
 125                         break;
 126                 case SAM_PWD_CHANGE_NOT_COMPLEX:
 127                         reject_string = "Password does not meet complexity requirements";
 128                         break;
 129                 case SAM_PWD_CHANGE_PWD_IN_HISTORY:
 130                         reject_string = "Password is already in password history";
 131                         break;
 132                 default:
 133                         reject_string = talloc_asprintf(mem_ctx, "Password must be at least %d characters long, and cannot match any of your %d previous passwords",
 134                                                         dominfo->min_password_length, dominfo->password_history_length);
 135                         break;
 136                 }
 137                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 138                                                 KRB5_KPASSWD_SOFTERROR,
 139                                                 reject_string,
 140                                                 error_blob);
 141         }
 142         if (!NT_STATUS_IS_OK(status)) {
 143                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 144                                                  KRB5_KPASSWD_HARDERROR,
 145                                                  talloc_asprintf(mem_ctx, "failed to set password: %s", nt_errstr(status)),
 146                                                  error_blob);
 147
 148         }
 149         return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SUCCESS,
 150                                         "Password changed",
 151                                         error_blob);
 152 }
 153
 154 /*
 155    A user password change
 156
 157    Return true if there is a valid error packet (or success) formed in
 158    the error_blob
 159 */
 160 static bool kpasswdd_change_password(struct kdc_server *kdc,
 161                                      TALLOC_CTX *mem_ctx,
 162                                      struct auth_session_info *session_info,
 163                                      const DATA_BLOB *password,
 164                                      DATA_BLOB *reply)
 165 {
 166         NTSTATUS status;
 167         enum samPwdChangeReason reject_reason;
 168         struct samr_DomInfo1 *dominfo;
 169         struct samr_Password *oldLmHash, *oldNtHash;
 170         struct ldb_context *samdb;
 171         const char * const attrs[] = { "dBCSPwd", "unicodePwd", NULL };
 172         struct ldb_message **res;
 173         int ret;
 174
 175         /* Fetch the old hashes to get the old password in order to perform
 176          * the password change operation. Naturally it would be much better to
 177          * have a password hash from an authentication around but this doesn't
 178          * seem to be the case here. */
 179         ret = gendb_search(kdc->samdb, mem_ctx, NULL, &res, attrs,
 180                            "(&(objectClass=user)(sAMAccountName=%s))",
 181                            session_info->server_info->account_name);
 182         if (ret != 1) {
 183                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 184                                                 KRB5_KPASSWD_ACCESSDENIED,
 185                                                 "No such user when changing password",
 186                                                 reply);
 187         }
 188
 189         status = samdb_result_passwords(mem_ctx, kdc->task->lp_ctx, res[0],
 190                                         &oldLmHash, &oldNtHash);
 191         if (!NT_STATUS_IS_OK(status)) {
 192                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 193                                                 KRB5_KPASSWD_ACCESSDENIED,
 194                                                 "Not permitted to change password",
 195                                                 reply);
 196         }
 197
 198         /* Start a SAM with user privileges for the password change */
 199         samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx,
 200                               session_info, 0);
 201         if (!samdb) {
 202                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 203                                                 KRB5_KPASSWD_HARDERROR,
 204                                                 "Failed to open samdb",
 205                                                 reply);
 206         }
 207
 208         DEBUG(3, ("Changing password of %s\\%s (%s)\n",
 209                   session_info->server_info->domain_name,
 210                   session_info->server_info->account_name,
 211                   dom_sid_string(mem_ctx, &session_info->security_token->sids[PRIMARY_USER_SID_INDEX])));
 212
 213         /* Performs the password change */
 214         status = samdb_set_password_sid(samdb, mem_ctx,
 215                                         &session_info->security_token->sids[PRIMARY_USER_SID_INDEX],
 216                                         password, NULL, NULL,
 217                                         oldLmHash, oldNtHash, /* this is a user password change */
 218                                         &reject_reason,
 219                                         &dominfo);
 220         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 221                                            status,
 222                                            reject_reason,
 223                                            dominfo,
 224                                            reply);
 225
 226 }
 227
 228 static bool kpasswd_process_request(struct kdc_server *kdc,
 229                                     TALLOC_CTX *mem_ctx,
 230                                     struct gensec_security *gensec_security,
 231                                     uint16_t version,
 232                                     DATA_BLOB *input,
 233                                     DATA_BLOB *reply)
 234 {
 235         struct auth_session_info *session_info;
 236         size_t pw_len;
 237
 238         if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security,
 239                                                  &session_info))) {
 240                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 241                                                 KRB5_KPASSWD_HARDERROR,
 242                                                 "gensec_session_info failed!",
 243                                                 reply);
 244         }
 245
 246         switch (version) {
 247         case KRB5_KPASSWD_VERS_CHANGEPW:
 248         {
 249                 DATA_BLOB password;
 250                 if (!convert_string_talloc_convenience(mem_ctx, lpcfg_iconv_convenience(kdc->task->lp_ctx),
 251                                                CH_UTF8, CH_UTF16,
 252                                                (const char *)input->data,
 253                                                input->length,
 254                                                (void **)&password.data, &pw_len, false)) {
 255                         return false;
 256                 }
 257                 password.length = pw_len;
 258
 259                 return kpasswdd_change_password(kdc, mem_ctx, session_info,
 260                                                 &password, reply);
 261         }
 262         case KRB5_KPASSWD_VERS_SETPW:
 263         {
 264                 NTSTATUS status;
 265                 enum samPwdChangeReason reject_reason = SAM_PWD_CHANGE_NO_ERROR;
 266                 struct samr_DomInfo1 *dominfo = NULL;
 267                 struct ldb_context *samdb;
 268                 krb5_context context = kdc->smb_krb5_context->krb5_context;
 269
 270                 ChangePasswdDataMS chpw;
 271                 DATA_BLOB password;
 272
 273                 krb5_principal principal;
 274                 char *set_password_on_princ;
 275                 struct ldb_dn *set_password_on_dn;
 276                 bool service_principal_name = false;
 277
 278                 size_t len;
 279                 int ret;
 280
 281                 ret = decode_ChangePasswdDataMS(input->data, input->length,
 282                                                 &chpw, &len);
 283                 if (ret) {
 284                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 285                                                         KRB5_KPASSWD_MALFORMED,
 286                                                         "failed to decode password change structure",
 287                                                         reply);
 288                 }
 289
 290                 if (!convert_string_talloc_convenience(mem_ctx, lpcfg_iconv_convenience(kdc->task->lp_ctx),
 291                                                CH_UTF8, CH_UTF16,
 292                                                (const char *)chpw.newpasswd.data,
 293                                                chpw.newpasswd.length,
 294                                                (void **)&password.data, &pw_len, false)) {
 295                         free_ChangePasswdDataMS(&chpw);
 296                         return false;
 297                 }
 298
 299                 password.length = pw_len;
 300
 301                 if ((chpw.targname && !chpw.targrealm)
 302                     || (!chpw.targname && chpw.targrealm)) {
 303                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 304                                                         KRB5_KPASSWD_MALFORMED,
 305                                                         "Realm and principal must be both present, or neither present",
 306                                                         reply);
 307                 }
 308                 if (chpw.targname && chpw.targrealm) {
 309                         krb5_build_principal_ext(kdc->smb_krb5_context->krb5_context,
 310                                                  &principal, strlen(*chpw.targrealm), *chpw.targrealm, 0);
 311                         if (copy_PrincipalName(chpw.targname, &principal->name)) {
 312                                 free_ChangePasswdDataMS(&chpw);
 313                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 314                                                                 KRB5_KPASSWD_MALFORMED,
 315                                                                 "failed to extract principal to set",
 316                                                                 reply);
 317                         }
 318                 } else {
 319                         free_ChangePasswdDataMS(&chpw);
 320                         return kpasswdd_change_password(kdc, mem_ctx, session_info,
 321                                                         &password, reply);
 322                 }
 323                 free_ChangePasswdDataMS(&chpw);
 324
 325                 if (principal->name.name_string.len >= 2) {
 326                         service_principal_name = true;
 327
 328                         /* We use this, rather than 'no realm' flag,
 329                          * as we don't want to accept a password
 330                          * change on a principal from another realm */
 331
 332                         if (krb5_unparse_name_short(context, principal, &set_password_on_princ) != 0) {
 333                                 krb5_free_principal(context, principal);
 334                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 335                                                                  KRB5_KPASSWD_MALFORMED,
 336                                                                  "krb5_unparse_name failed!",
 337                                                                  reply);
 338                         }
 339                 } else {
 340                         if (krb5_unparse_name(context, principal, &set_password_on_princ) != 0) {
 341                                 krb5_free_principal(context, principal);
 342                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 343                                                                  KRB5_KPASSWD_MALFORMED,
 344                                                                  "krb5_unparse_name failed!",
 345                                                                  reply);
 346                         }
 347                 }
 348                 krb5_free_principal(context, principal);
 349
 350                 samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, session_info, 0);
 351                 if (!samdb) {
 352                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 353                                                          KRB5_KPASSWD_HARDERROR,
 354                                                          "Unable to open database!",
 355                                                          reply);
 356                 }
 357
 358                 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
 359                           session_info->server_info->domain_name,
 360                           session_info->server_info->account_name,
 361                           dom_sid_string(mem_ctx, &session_info->security_token->sids[PRIMARY_USER_SID_INDEX]),
 362                           set_password_on_princ));
 363                 ret = ldb_transaction_start(samdb);
 364                 if (ret != LDB_SUCCESS) {
 365                         status = NT_STATUS_TRANSACTION_ABORTED;
 366                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 367                                                            status,
 368                                                            SAM_PWD_CHANGE_NO_ERROR,
 369                                                            NULL,
 370                                                            reply);
 371                 }
 372
 373                 if (service_principal_name) {
 374                         status = crack_service_principal_name(samdb, mem_ctx,
 375                                                               set_password_on_princ,
 376                                                               &set_password_on_dn, NULL);
 377                 } else {
 378                         status = crack_user_principal_name(samdb, mem_ctx,
 379                                                            set_password_on_princ,
 380                                                            &set_password_on_dn, NULL);
 381                 }
 382                 free(set_password_on_princ);
 383                 if (!NT_STATUS_IS_OK(status)) {
 384                         ldb_transaction_cancel(samdb);
 385                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 386                                                            status,
 387                                                            SAM_PWD_CHANGE_NO_ERROR,
 388                                                            NULL,
 389                                                            reply);
 390                 }
 391
 392                 if (NT_STATUS_IS_OK(status)) {
 393                         /* Admin password set */
 394                         status = samdb_set_password(samdb, mem_ctx,
 395                                                     set_password_on_dn, NULL,
 396                                                     &password, NULL, NULL,
 397                                                     NULL, NULL, /* this is not a user password change */
 398                                                     &reject_reason, &dominfo);
 399                 }
 400
 401                 if (NT_STATUS_IS_OK(status)) {
 402                         ret = ldb_transaction_commit(samdb);
 403                         if (ret != LDB_SUCCESS) {
 404                                 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
 405                                          ldb_dn_get_linearized(set_password_on_dn),
 406                                          ldb_errstring(samdb)));
 407                                 status = NT_STATUS_TRANSACTION_ABORTED;
 408                         }
 409                 } else {
 410                         ldb_transaction_cancel(samdb);
 411                 }
 412                 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 413                                                    status,
 414                                                    reject_reason,
 415                                                    dominfo,
 416                                                    reply);
 417         }
 418         default:
 419                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 420                                                  KRB5_KPASSWD_BAD_VERSION,
 421                                                  talloc_asprintf(mem_ctx,
 422                                                                  "Protocol version %u not supported",
 423                                                                  version),
 424                                                  reply);
 425         }
 426 }
 427
 428 enum kdc_process_ret kpasswdd_process(struct kdc_server *kdc,
 429                                       TALLOC_CTX *mem_ctx,
 430                                       DATA_BLOB *input,
 431                                       DATA_BLOB *reply,
 432                                       struct tsocket_address *peer_addr,
 433                                       struct tsocket_address *my_addr,
 434                                       int datagram_reply)
 435 {
 436         bool ret;
 437         const uint16_t header_len = 6;
 438         uint16_t len;
 439         uint16_t ap_req_len;
 440         uint16_t krb_priv_len;
 441         uint16_t version;
 442         NTSTATUS nt_status;
 443         DATA_BLOB ap_req, krb_priv_req;
 444         DATA_BLOB krb_priv_rep = data_blob(NULL, 0);
 445         DATA_BLOB ap_rep = data_blob(NULL, 0);
 446         DATA_BLOB kpasswd_req, kpasswd_rep;
 447         struct cli_credentials *server_credentials;
 448         struct gensec_security *gensec_security;
 449         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 450
 451         char *keytab_name;
 452
 453         if (!tmp_ctx) {
 454                 return KDC_PROCESS_FAILED;
 455         }
 456
 457         if (kdc->am_rodc) {
 458                 talloc_free(tmp_ctx);
 459                 return KDC_PROCESS_PROXY;
 460         }
 461
 462         /* Be parinoid.  We need to ensure we don't just let the
 463          * caller lead us into a buffer overflow */
 464         if (input->length <= header_len) {
 465                 talloc_free(tmp_ctx);
 466                 return KDC_PROCESS_FAILED;
 467         }
 468
 469         len = RSVAL(input->data, 0);
 470         if (input->length != len) {
 471                 talloc_free(tmp_ctx);
 472                 return KDC_PROCESS_FAILED;
 473         }
 474
 475         /* There are two different versions of this protocol so far,
 476          * plus others in the standards pipe.  Fortunetly they all
 477          * take a very similar framing */
 478         version = RSVAL(input->data, 2);
 479         ap_req_len = RSVAL(input->data, 4);
 480         if ((ap_req_len >= len) || (ap_req_len + header_len) >= len) {
 481                 talloc_free(tmp_ctx);
 482                 return KDC_PROCESS_FAILED;
 483         }
 484
 485         krb_priv_len = len - ap_req_len;
 486         ap_req = data_blob_const(&input->data[header_len], ap_req_len);
 487         krb_priv_req = data_blob_const(&input->data[header_len + ap_req_len], krb_priv_len);
 488
 489         server_credentials = cli_credentials_init(tmp_ctx);
 490         if (!server_credentials) {
 491                 DEBUG(1, ("Failed to init server credentials\n"));
 492                 talloc_free(tmp_ctx);
 493                 return KDC_PROCESS_FAILED;
 494         }
 495
 496         /* We want the credentials subsystem to use the krb5 context
 497          * we already have, rather than a new context */
 498         cli_credentials_set_krb5_context(server_credentials, kdc->smb_krb5_context);
 499         cli_credentials_set_conf(server_credentials, kdc->task->lp_ctx);
 500
 501         keytab_name = talloc_asprintf(server_credentials, "HDB:samba4&%p", kdc->base_ctx);
 502
 503         cli_credentials_set_username(server_credentials, "kadmin/changepw", CRED_SPECIFIED);
 504         ret = cli_credentials_set_keytab_name(server_credentials, kdc->task->lp_ctx, keytab_name, CRED_SPECIFIED);
 505         if (ret != 0) {
 506                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 507                                                        KRB5_KPASSWD_HARDERROR,
 508                                                        talloc_asprintf(mem_ctx,
 509                                                                        "Failed to obtain server credentials for kadmin/changepw: %s\n",
 510                                                                        nt_errstr(nt_status)),
 511                                                        &krb_priv_rep);
 512                 ap_rep.length = 0;
 513                 if (ret) {
 514                         goto reply;
 515                 }
 516                 talloc_free(tmp_ctx);
 517                 return ret;
 518         }
 519
 520         /* We don't strictly need to call this wrapper, and could call
 521          * gensec_server_start directly, as we have no need for NTLM
 522          * and we have a PAC, but this ensures that the wrapper can be
 523          * safely extended for other helpful things in future */
 524         nt_status = samba_server_gensec_start(tmp_ctx, kdc->task->event_ctx,
 525                                               kdc->task->msg_ctx,
 526                                               kdc->task->lp_ctx,
 527                                               server_credentials,
 528                                               "kpasswd",
 529                                               &gensec_security);
 530         if (!NT_STATUS_IS_OK(nt_status)) {
 531                 talloc_free(tmp_ctx);
 532                 return KDC_PROCESS_FAILED;
 533         }
 534
 535         /* The kerberos PRIV packets include these addresses.  MIT
 536          * clients check that they are present */
 537 #if 0
 538         /* Skip this part for now, it breaks with a NetAPP filer and
 539          * in any case where the client address is behind NAT.  If
 540          * older MIT clients need this, we might have to insert more
 541          * complex code */
 542
 543         nt_status = gensec_set_local_address(gensec_security, peer_addr);
 544         if (!NT_STATUS_IS_OK(nt_status)) {
 545                 talloc_free(tmp_ctx);
 546                 return KDC_PROCESS_FAILED;
 547         }
 548 #endif
 549
 550         nt_status = gensec_set_local_address(gensec_security, my_addr);
 551         if (!NT_STATUS_IS_OK(nt_status)) {
 552                 talloc_free(tmp_ctx);
 553                 return KDC_PROCESS_FAILED;
 554         }
 555
 556         /* We want the GENSEC wrap calls to generate PRIV tokens */
 557         gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
 558
 559         nt_status = gensec_start_mech_by_name(gensec_security, "krb5");
 560         if (!NT_STATUS_IS_OK(nt_status)) {
 561                 talloc_free(tmp_ctx);
 562                 return KDC_PROCESS_FAILED;
 563         }
 564
 565         /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
 566         nt_status = gensec_update(gensec_security, tmp_ctx, ap_req, &ap_rep);
 567         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 568
 569                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 570                                                        KRB5_KPASSWD_HARDERROR,
 571                                                        talloc_asprintf(mem_ctx,
 572                                                                        "gensec_update failed: %s",
 573                                                                        nt_errstr(nt_status)),
 574                                                        &krb_priv_rep);
 575                 ap_rep.length = 0;
 576                 if (ret) {
 577                         goto reply;
 578                 }
 579                 talloc_free(tmp_ctx);
 580                 return KDC_PROCESS_FAILED;
 581         }
 582
 583         /* Extract the data from the KRB-PRIV half of the message */
 584         nt_status = gensec_unwrap(gensec_security, tmp_ctx, &krb_priv_req, &kpasswd_req);
 585         if (!NT_STATUS_IS_OK(nt_status)) {
 586                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 587                                                        KRB5_KPASSWD_HARDERROR,
 588                                                        talloc_asprintf(mem_ctx,
 589                                                                        "gensec_unwrap failed: %s",
 590                                                                        nt_errstr(nt_status)),
 591                                                        &krb_priv_rep);
 592                 ap_rep.length = 0;
 593                 if (ret) {
 594                         goto reply;
 595                 }
 596                 talloc_free(tmp_ctx);
 597                 return KDC_PROCESS_FAILED;
 598         }
 599
 600         /* Figure out something to do with it (probably changing a password...) */
 601         ret = kpasswd_process_request(kdc, tmp_ctx,
 602                                       gensec_security,
 603                                       version,
 604                                       &kpasswd_req, &kpasswd_rep);
 605         if (!ret) {
 606                 /* Argh! */
 607                 talloc_free(tmp_ctx);
 608                 return KDC_PROCESS_FAILED;
 609         }
 610
 611         /* And wrap up the reply: This ensures that the error message
 612          * or success can be verified by the client */
 613         nt_status = gensec_wrap(gensec_security, tmp_ctx,
 614                                 &kpasswd_rep, &krb_priv_rep);
 615         if (!NT_STATUS_IS_OK(nt_status)) {
 616                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 617                                                        KRB5_KPASSWD_HARDERROR,
 618                                                        talloc_asprintf(mem_ctx,
 619                                                                        "gensec_wrap failed: %s",
 620                                                                        nt_errstr(nt_status)),
 621                                                        &krb_priv_rep);
 622                 ap_rep.length = 0;
 623                 if (ret) {
 624                         goto reply;
 625                 }
 626                 talloc_free(tmp_ctx);
 627                 return KDC_PROCESS_FAILED;
 628         }
 629
 630 reply:
 631         *reply = data_blob_talloc(mem_ctx, NULL, krb_priv_rep.length + ap_rep.length + header_len);
 632         if (!reply->data) {
 633                 talloc_free(tmp_ctx);
 634                 return KDC_PROCESS_FAILED;
 635         }
 636
 637         RSSVAL(reply->data, 0, reply->length);
 638         RSSVAL(reply->data, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
 639         RSSVAL(reply->data, 4, ap_rep.length);
 640         memcpy(reply->data + header_len,
 641                ap_rep.data,
 642                ap_rep.length);
 643         memcpy(reply->data + header_len + ap_rep.length,
 644                krb_priv_rep.data,
 645                krb_priv_rep.length);
 646
 647         talloc_free(tmp_ctx);
 648         return KDC_PROCESS_OK;
 649 }
 650