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 "system/network.h"
  28 #include "../lib/util/dlinklist.h"
  29 #include "lib/ldb/include/ldb.h"
  30 #include "auth/gensec/gensec.h"
  31 #include "auth/credentials/credentials.h"
  32 #include "auth/credentials/credentials_krb5.h"
  33 #include "auth/auth.h"
  34 #include "dsdb/samdb/samdb.h"
  35 #include "rpc_server/dcerpc_server.h"
  36 #include "rpc_server/samr/proto.h"
  37 #include "libcli/security/security.h"
  38 #include "param/param.h"
  39 #include "kdc/kdc.h"
  40
  41 /* TODO: remove all SAMBA4_INTERNAL_HEIMDAL stuff from this file */
  42 #ifdef SAMBA4_INTERNAL_HEIMDAL
  43 #include "heimdal_build/kpasswdd-glue.h"
  44 #endif
  45
  46 /* hold information about one kdc socket */
  47 struct kpasswd_socket {
  48         struct socket_context *sock;
  49         struct kdc_server *kdc;
  50         struct tevent_fd *fde;
  51
  52         /* a queue of outgoing replies that have been deferred */
  53         struct kdc_reply *send_queue;
  54 };
  55
  56 /* Return true if there is a valid error packet formed in the error_blob */
  57 static bool kpasswdd_make_error_reply(struct kdc_server *kdc,
  58                                      TALLOC_CTX *mem_ctx,
  59                                      uint16_t result_code,
  60                                      const char *error_string,
  61                                      DATA_BLOB *error_blob)
  62 {
  63         char *error_string_utf8;
  64         size_t len;
  65
  66         DEBUG(result_code ? 3 : 10, ("kpasswdd: %s\n", error_string));
  67
  68         if (!push_utf8_talloc(mem_ctx, &error_string_utf8, error_string, &len)) {
  69                 return false;
  70         }
  71
  72         *error_blob = data_blob_talloc(mem_ctx, NULL, 2 + len + 1);
  73         if (!error_blob->data) {
  74                 return false;
  75         }
  76         RSSVAL(error_blob->data, 0, result_code);
  77         memcpy(error_blob->data + 2, error_string_utf8, len + 1);
  78         return true;
  79 }
  80
  81 /* Return true if there is a valid error packet formed in the error_blob */
  82 static bool kpasswdd_make_unauth_error_reply(struct kdc_server *kdc,
  83                                             TALLOC_CTX *mem_ctx,
  84                                             uint16_t result_code,
  85                                             const char *error_string,
  86                                             DATA_BLOB *error_blob)
  87 {
  88         bool ret;
  89         int kret;
  90         DATA_BLOB error_bytes;
  91         krb5_data k5_error_bytes, k5_error_blob;
  92         ret = kpasswdd_make_error_reply(kdc, mem_ctx, result_code, error_string,
  93                                        &error_bytes);
  94         if (!ret) {
  95                 return false;
  96         }
  97         k5_error_bytes.data = error_bytes.data;
  98         k5_error_bytes.length = error_bytes.length;
  99         kret = krb5_mk_error(kdc->smb_krb5_context->krb5_context,
 100                              result_code, NULL, &k5_error_bytes,
 101                              NULL, NULL, NULL, NULL, &k5_error_blob);
 102         if (kret) {
 103                 return false;
 104         }
 105         *error_blob = data_blob_talloc(mem_ctx, k5_error_blob.data, k5_error_blob.length);
 106         krb5_data_free(&k5_error_blob);
 107         if (!error_blob->data) {
 108                 return false;
 109         }
 110         return true;
 111 }
 112
 113 static bool kpasswd_make_pwchange_reply(struct kdc_server *kdc,
 114                                         TALLOC_CTX *mem_ctx,
 115                                         NTSTATUS status,
 116                                         enum samr_RejectReason reject_reason,
 117                                         struct samr_DomInfo1 *dominfo,
 118                                         DATA_BLOB *error_blob)
 119 {
 120         if (NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_USER)) {
 121                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 122                                                 KRB5_KPASSWD_ACCESSDENIED,
 123                                                 "No such user when changing password",
 124                                                 error_blob);
 125         }
 126         if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
 127                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 128                                                 KRB5_KPASSWD_ACCESSDENIED,
 129                                                 "Not permitted to change password",
 130                                                 error_blob);
 131         }
 132         if (dominfo && NT_STATUS_EQUAL(status, NT_STATUS_PASSWORD_RESTRICTION)) {
 133                 const char *reject_string;
 134                 switch (reject_reason) {
 135                 case SAMR_REJECT_TOO_SHORT:
 136                         reject_string = talloc_asprintf(mem_ctx, "Password too short, password must be at least %d characters long",
 137                                                         dominfo->min_password_length);
 138                         break;
 139                 case SAMR_REJECT_COMPLEXITY:
 140                         reject_string = "Password does not meet complexity requirements";
 141                         break;
 142                 case SAMR_REJECT_IN_HISTORY:
 143                         reject_string = "Password is already in password history";
 144                         break;
 145                 case SAMR_REJECT_OTHER:
 146                 default:
 147                         reject_string = talloc_asprintf(mem_ctx, "Password must be at least %d characters long, and cannot match any of your %d previous passwords",
 148                                                         dominfo->min_password_length, dominfo->password_history_length);
 149                         break;
 150                 }
 151                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 152                                                 KRB5_KPASSWD_SOFTERROR,
 153                                                 reject_string,
 154                                                 error_blob);
 155         }
 156         if (!NT_STATUS_IS_OK(status)) {
 157                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 158                                                  KRB5_KPASSWD_HARDERROR,
 159                                                  talloc_asprintf(mem_ctx, "failed to set password: %s", nt_errstr(status)),
 160                                                  error_blob);
 161
 162         }
 163         return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SUCCESS,
 164                                         "Password changed",
 165                                         error_blob);
 166 }
 167
 168 /*
 169    A user password change
 170
 171    Return true if there is a valid error packet (or sucess) formed in
 172    the error_blob
 173 */
 174 static bool kpasswdd_change_password(struct kdc_server *kdc,
 175                                      TALLOC_CTX *mem_ctx,
 176                                      struct auth_session_info *session_info,
 177                                      const DATA_BLOB *password,
 178                                      DATA_BLOB *reply)
 179 {
 180         NTSTATUS status;
 181         enum samr_RejectReason reject_reason;
 182         struct samr_DomInfo1 *dominfo;
 183         struct ldb_context *samdb;
 184
 185         samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, system_session(mem_ctx, kdc->task->lp_ctx));
 186         if (!samdb) {
 187                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 188                                                 KRB5_KPASSWD_HARDERROR,
 189                                                 "Failed to open samdb",
 190                                                 reply);
 191         }
 192
 193         DEBUG(3, ("Changing password of %s\\%s (%s)\n",
 194                   session_info->server_info->domain_name,
 195                   session_info->server_info->account_name,
 196                   dom_sid_string(mem_ctx, session_info->security_token->user_sid)));
 197
 198         /* User password change */
 199         status = samdb_set_password_sid(samdb, mem_ctx,
 200                                         session_info->security_token->user_sid,
 201                                         password, NULL, NULL,
 202                                         true, /* this is a user password change */
 203                                         &reject_reason,
 204                                         &dominfo);
 205         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 206                                            status,
 207                                            reject_reason,
 208                                            dominfo,
 209                                            reply);
 210
 211 }
 212
 213 static bool kpasswd_process_request(struct kdc_server *kdc,
 214                                     TALLOC_CTX *mem_ctx,
 215                                     struct gensec_security *gensec_security,
 216                                     uint16_t version,
 217                                     DATA_BLOB *input,
 218                                     DATA_BLOB *reply)
 219 {
 220         struct auth_session_info *session_info;
 221         size_t pw_len;
 222
 223         if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security,
 224                                                  &session_info))) {
 225                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 226                                                 KRB5_KPASSWD_HARDERROR,
 227                                                 "gensec_session_info failed!",
 228                                                 reply);
 229         }
 230
 231         switch (version) {
 232         case KRB5_KPASSWD_VERS_CHANGEPW:
 233         {
 234                 DATA_BLOB password;
 235                 if (!convert_string_talloc_convenience(mem_ctx, lp_iconv_convenience(kdc->task->lp_ctx),
 236                                                CH_UTF8, CH_UTF16,
 237                                                (const char *)input->data,
 238                                                input->length,
 239                                                (void **)&password.data, &pw_len, false)) {
 240                         return false;
 241                 }
 242                 password.length = pw_len;
 243
 244                 return kpasswdd_change_password(kdc, mem_ctx, session_info,
 245                                                 &password, reply);
 246                 break;
 247         }
 248         case KRB5_KPASSWD_VERS_SETPW:
 249         {
 250                 NTSTATUS status;
 251                 enum samr_RejectReason reject_reason = SAMR_REJECT_OTHER;
 252                 struct samr_DomInfo1 *dominfo = NULL;
 253                 struct ldb_context *samdb;
 254                 struct ldb_message *msg;
 255                 krb5_context context = kdc->smb_krb5_context->krb5_context;
 256
 257                 ChangePasswdDataMS chpw;
 258                 DATA_BLOB password;
 259
 260                 krb5_principal principal;
 261                 char *set_password_on_princ;
 262                 struct ldb_dn *set_password_on_dn;
 263
 264                 size_t len;
 265                 int ret;
 266
 267                 msg = ldb_msg_new(mem_ctx);
 268                 if (!msg) {
 269                         return false;
 270                 }
 271
 272                 ret = decode_ChangePasswdDataMS(input->data, input->length,
 273                                                 &chpw, &len);
 274                 if (ret) {
 275                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 276                                                         KRB5_KPASSWD_MALFORMED,
 277                                                         "failed to decode password change structure",
 278                                                         reply);
 279                 }
 280
 281                 if (!convert_string_talloc_convenience(mem_ctx, lp_iconv_convenience(kdc->task->lp_ctx),
 282                                                CH_UTF8, CH_UTF16,
 283                                                (const char *)chpw.newpasswd.data,
 284                                                chpw.newpasswd.length,
 285                                                (void **)&password.data, &pw_len, false)) {
 286                         free_ChangePasswdDataMS(&chpw);
 287                         return false;
 288                 }
 289
 290                 password.length = pw_len;
 291
 292                 if ((chpw.targname && !chpw.targrealm)
 293                     || (!chpw.targname && chpw.targrealm)) {
 294                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 295                                                         KRB5_KPASSWD_MALFORMED,
 296                                                         "Realm and principal must be both present, or neither present",
 297                                                         reply);
 298                 }
 299                 if (chpw.targname && chpw.targrealm) {
 300 #ifdef SAMBA4_INTERNAL_HEIMDAL
 301                         if (_krb5_principalname2krb5_principal(kdc->smb_krb5_context->krb5_context,
 302                                                                &principal, *chpw.targname,
 303                                                                *chpw.targrealm) != 0) {
 304                                 free_ChangePasswdDataMS(&chpw);
 305                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 306                                                                 KRB5_KPASSWD_MALFORMED,
 307                                                                 "failed to extract principal to set",
 308                                                                 reply);
 309
 310                         }
 311 #else /* SAMBA4_INTERNAL_HEIMDAL */
 312                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 313                                                                 KRB5_KPASSWD_BAD_VERSION,
 314                                                                 "Operation Not Implemented",
 315                                                                 reply);
 316 #endif /* SAMBA4_INTERNAL_HEIMDAL */
 317                 } else {
 318                         free_ChangePasswdDataMS(&chpw);
 319                         return kpasswdd_change_password(kdc, mem_ctx, session_info,
 320                                                         &password, reply);
 321                 }
 322                 free_ChangePasswdDataMS(&chpw);
 323
 324                 if (krb5_unparse_name(context, principal, &set_password_on_princ) != 0) {
 325                         krb5_free_principal(context, principal);
 326                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 327                                                         KRB5_KPASSWD_MALFORMED,
 328                                                         "krb5_unparse_name failed!",
 329                                                         reply);
 330                 }
 331
 332                 krb5_free_principal(context, principal);
 333
 334                 samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, session_info);
 335                 if (!samdb) {
 336                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 337                                                          KRB5_KPASSWD_HARDERROR,
 338                                                          "Unable to open database!",
 339                                                          reply);
 340                 }
 341
 342                 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
 343                           session_info->server_info->domain_name,
 344                           session_info->server_info->account_name,
 345                           dom_sid_string(mem_ctx, session_info->security_token->user_sid),
 346                           set_password_on_princ));
 347                 ret = ldb_transaction_start(samdb);
 348                 if (ret) {
 349                         status = NT_STATUS_TRANSACTION_ABORTED;
 350                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 351                                                            status,
 352                                                            SAMR_REJECT_OTHER,
 353                                                            NULL,
 354                                                            reply);
 355                 }
 356
 357                 status = crack_user_principal_name(samdb, mem_ctx,
 358                                                    set_password_on_princ,
 359                                                    &set_password_on_dn, NULL);
 360                 free(set_password_on_princ);
 361                 if (!NT_STATUS_IS_OK(status)) {
 362                         ldb_transaction_cancel(samdb);
 363                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 364                                                            status,
 365                                                            SAMR_REJECT_OTHER,
 366                                                            NULL,
 367                                                            reply);
 368                 }
 369
 370                 msg = ldb_msg_new(mem_ctx);
 371                 if (msg == NULL) {
 372                         ldb_transaction_cancel(samdb);
 373                         status = NT_STATUS_NO_MEMORY;
 374                 } else {
 375                         msg->dn = ldb_dn_copy(msg, set_password_on_dn);
 376                         if (!msg->dn) {
 377                                 status = NT_STATUS_NO_MEMORY;
 378                         }
 379                 }
 380
 381                 if (NT_STATUS_IS_OK(status)) {
 382                         /* Admin password set */
 383                         status = samdb_set_password(samdb, mem_ctx,
 384                                                     set_password_on_dn, NULL,
 385                                                     msg, &password, NULL, NULL,
 386                                                     false, /* this is not a user password change */
 387                                                     &reject_reason, &dominfo);
 388                 }
 389
 390                 if (NT_STATUS_IS_OK(status)) {
 391                         /* modify the samdb record */
 392                         ret = samdb_replace(samdb, mem_ctx, msg);
 393                         if (ret != 0) {
 394                                 DEBUG(2,("Failed to modify record to set password on %s: %s\n",
 395                                          ldb_dn_get_linearized(msg->dn),
 396                                          ldb_errstring(samdb)));
 397                                 status = NT_STATUS_ACCESS_DENIED;
 398                         }
 399                 }
 400                 if (NT_STATUS_IS_OK(status)) {
 401                         ret = ldb_transaction_commit(samdb);
 402                         if (ret != 0) {
 403                                 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
 404                                          ldb_dn_get_linearized(msg->dn),
 405                                          ldb_errstring(samdb)));
 406                                 status = NT_STATUS_TRANSACTION_ABORTED;
 407                         }
 408                 } else {
 409                         ldb_transaction_cancel(samdb);
 410                 }
 411                 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 412                                                    status,
 413                                                    reject_reason,
 414                                                    dominfo,
 415                                                    reply);
 416         }
 417         default:
 418                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 419                                                  KRB5_KPASSWD_BAD_VERSION,
 420                                                  talloc_asprintf(mem_ctx,
 421                                                                  "Protocol version %u not supported",
 422                                                                  version),
 423                                                  reply);
 424         }
 425         return true;
 426 }
 427
 428 bool kpasswdd_process(struct kdc_server *kdc,
 429                       TALLOC_CTX *mem_ctx,
 430                       DATA_BLOB *input,
 431                       DATA_BLOB *reply,
 432                       struct socket_address *peer_addr,
 433                       struct socket_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 false;
 455         }
 456
 457         /* Be parinoid.  We need to ensure we don't just let the
 458          * caller lead us into a buffer overflow */
 459         if (input->length <= header_len) {
 460                 talloc_free(tmp_ctx);
 461                 return false;
 462         }
 463
 464         len = RSVAL(input->data, 0);
 465         if (input->length != len) {
 466                 talloc_free(tmp_ctx);
 467                 return false;
 468         }
 469
 470         /* There are two different versions of this protocol so far,
 471          * plus others in the standards pipe.  Fortunetly they all
 472          * take a very similar framing */
 473         version = RSVAL(input->data, 2);
 474         ap_req_len = RSVAL(input->data, 4);
 475         if ((ap_req_len >= len) || (ap_req_len + header_len) >= len) {
 476                 talloc_free(tmp_ctx);
 477                 return false;
 478         }
 479
 480         krb_priv_len = len - ap_req_len;
 481         ap_req = data_blob_const(&input->data[header_len], ap_req_len);
 482         krb_priv_req = data_blob_const(&input->data[header_len + ap_req_len], krb_priv_len);
 483
 484         server_credentials = cli_credentials_init(tmp_ctx);
 485         if (!server_credentials) {
 486                 DEBUG(1, ("Failed to init server credentials\n"));
 487                 return false;
 488         }
 489
 490         /* We want the credentials subsystem to use the krb5 context
 491          * we already have, rather than a new context */
 492         cli_credentials_set_krb5_context(server_credentials, kdc->smb_krb5_context);
 493         cli_credentials_set_conf(server_credentials, kdc->task->lp_ctx);
 494
 495         keytab_name = talloc_asprintf(server_credentials, "HDB:samba4&%p", kdc->hdb_samba4_context);
 496
 497         cli_credentials_set_username(server_credentials, "kadmin/changepw", CRED_SPECIFIED);
 498         ret = cli_credentials_set_keytab_name(server_credentials, kdc->task->event_ctx, kdc->task->lp_ctx, keytab_name, CRED_SPECIFIED);
 499         if (ret != 0) {
 500                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 501                                                        KRB5_KPASSWD_HARDERROR,
 502                                                        talloc_asprintf(mem_ctx,
 503                                                                        "Failed to obtain server credentials for kadmin/changepw: %s\n",
 504                                                                        nt_errstr(nt_status)),
 505                                                        &krb_priv_rep);
 506                 ap_rep.length = 0;
 507                 if (ret) {
 508                         goto reply;
 509                 }
 510                 talloc_free(tmp_ctx);
 511                 return ret;
 512         }
 513
 514         /* We don't strictly need to call this wrapper, and could call
 515          * gensec_server_start directly, as we have no need for NTLM
 516          * and we have a PAC, but this ensures that the wrapper can be
 517          * safely extended for other helpful things in future */
 518         nt_status = samba_server_gensec_start(tmp_ctx, kdc->task->event_ctx,
 519                                               kdc->task->msg_ctx,
 520                                               kdc->task->lp_ctx,
 521                                               server_credentials,
 522                                               "kpasswd",
 523                                               &gensec_security);
 524         if (!NT_STATUS_IS_OK(nt_status)) {
 525                 talloc_free(tmp_ctx);
 526                 return false;
 527         }
 528
 529         /* The kerberos PRIV packets include these addresses.  MIT
 530          * clients check that they are present */
 531 #if 0
 532         /* Skip this part for now, it breaks with a NetAPP filer and
 533          * in any case where the client address is behind NAT.  If
 534          * older MIT clients need this, we might have to insert more
 535          * complex code */
 536
 537         nt_status = gensec_set_peer_addr(gensec_security, peer_addr);
 538         if (!NT_STATUS_IS_OK(nt_status)) {
 539                 talloc_free(tmp_ctx);
 540                 return false;
 541         }
 542 #endif
 543
 544         nt_status = gensec_set_my_addr(gensec_security, my_addr);
 545         if (!NT_STATUS_IS_OK(nt_status)) {
 546                 talloc_free(tmp_ctx);
 547                 return false;
 548         }
 549
 550         /* We want the GENSEC wrap calls to generate PRIV tokens */
 551         gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
 552
 553         nt_status = gensec_start_mech_by_name(gensec_security, "krb5");
 554         if (!NT_STATUS_IS_OK(nt_status)) {
 555                 talloc_free(tmp_ctx);
 556                 return false;
 557         }
 558
 559         /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
 560         nt_status = gensec_update(gensec_security, tmp_ctx, ap_req, &ap_rep);
 561         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 562
 563                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 564                                                        KRB5_KPASSWD_HARDERROR,
 565                                                        talloc_asprintf(mem_ctx,
 566                                                                        "gensec_update failed: %s",
 567                                                                        nt_errstr(nt_status)),
 568                                                        &krb_priv_rep);
 569                 ap_rep.length = 0;
 570                 if (ret) {
 571                         goto reply;
 572                 }
 573                 talloc_free(tmp_ctx);
 574                 return ret;
 575         }
 576
 577         /* Extract the data from the KRB-PRIV half of the message */
 578         nt_status = gensec_unwrap(gensec_security, tmp_ctx, &krb_priv_req, &kpasswd_req);
 579         if (!NT_STATUS_IS_OK(nt_status)) {
 580                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 581                                                        KRB5_KPASSWD_HARDERROR,
 582                                                        talloc_asprintf(mem_ctx,
 583                                                                        "gensec_unwrap failed: %s",
 584                                                                        nt_errstr(nt_status)),
 585                                                        &krb_priv_rep);
 586                 ap_rep.length = 0;
 587                 if (ret) {
 588                         goto reply;
 589                 }
 590                 talloc_free(tmp_ctx);
 591                 return ret;
 592         }
 593
 594         /* Figure out something to do with it (probably changing a password...) */
 595         ret = kpasswd_process_request(kdc, tmp_ctx,
 596                                       gensec_security,
 597                                       version,
 598                                       &kpasswd_req, &kpasswd_rep);
 599         if (!ret) {
 600                 /* Argh! */
 601                 return false;
 602         }
 603
 604         /* And wrap up the reply: This ensures that the error message
 605          * or success can be verified by the client */
 606         nt_status = gensec_wrap(gensec_security, tmp_ctx,
 607                                 &kpasswd_rep, &krb_priv_rep);
 608         if (!NT_STATUS_IS_OK(nt_status)) {
 609                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 610                                                        KRB5_KPASSWD_HARDERROR,
 611                                                        talloc_asprintf(mem_ctx,
 612                                                                        "gensec_wrap failed: %s",
 613                                                                        nt_errstr(nt_status)),
 614                                                        &krb_priv_rep);
 615                 ap_rep.length = 0;
 616                 if (ret) {
 617                         goto reply;
 618                 }
 619                 talloc_free(tmp_ctx);
 620                 return ret;
 621         }
 622
 623 reply:
 624         *reply = data_blob_talloc(mem_ctx, NULL, krb_priv_rep.length + ap_rep.length + header_len);
 625         if (!reply->data) {
 626                 return false;
 627         }
 628
 629         RSSVAL(reply->data, 0, reply->length);
 630         RSSVAL(reply->data, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
 631         RSSVAL(reply->data, 4, ap_rep.length);
 632         memcpy(reply->data + header_len,
 633                ap_rep.data,
 634                ap_rep.length);
 635         memcpy(reply->data + header_len + ap_rep.length,
 636                krb_priv_rep.data,
 637                krb_priv_rep.length);
 638
 639         talloc_free(tmp_ctx);
 640         return ret;
 641 }
 642