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 "rpc_server/dcerpc_server.h"
  37 #include "rpc_server/samr/proto.h"
  38 #include "libcli/security/security.h"
  39 #include "param/param.h"
  40 #include "kdc/kdc.h"
  41
  42 /* TODO: remove all SAMBA4_INTERNAL_HEIMDAL stuff from this file */
  43 #ifdef SAMBA4_INTERNAL_HEIMDAL
  44 #include "heimdal_build/kpasswdd-glue.h"
  45 #endif
  46
  47 /* Return true if there is a valid error packet formed in the error_blob */
  48 static bool kpasswdd_make_error_reply(struct kdc_server *kdc,
  49                                      TALLOC_CTX *mem_ctx,
  50                                      uint16_t result_code,
  51                                      const char *error_string,
  52                                      DATA_BLOB *error_blob)
  53 {
  54         char *error_string_utf8;
  55         size_t len;
  56
  57         DEBUG(result_code ? 3 : 10, ("kpasswdd: %s\n", error_string));
  58
  59         if (!push_utf8_talloc(mem_ctx, &error_string_utf8, error_string, &len)) {
  60                 return false;
  61         }
  62
  63         *error_blob = data_blob_talloc(mem_ctx, NULL, 2 + len + 1);
  64         if (!error_blob->data) {
  65                 return false;
  66         }
  67         RSSVAL(error_blob->data, 0, result_code);
  68         memcpy(error_blob->data + 2, error_string_utf8, len + 1);
  69         return true;
  70 }
  71
  72 /* Return true if there is a valid error packet formed in the error_blob */
  73 static bool kpasswdd_make_unauth_error_reply(struct kdc_server *kdc,
  74                                             TALLOC_CTX *mem_ctx,
  75                                             uint16_t result_code,
  76                                             const char *error_string,
  77                                             DATA_BLOB *error_blob)
  78 {
  79         bool ret;
  80         int kret;
  81         DATA_BLOB error_bytes;
  82         krb5_data k5_error_bytes, k5_error_blob;
  83         ret = kpasswdd_make_error_reply(kdc, mem_ctx, result_code, error_string,
  84                                        &error_bytes);
  85         if (!ret) {
  86                 return false;
  87         }
  88         k5_error_bytes.data = error_bytes.data;
  89         k5_error_bytes.length = error_bytes.length;
  90         kret = krb5_mk_error(kdc->smb_krb5_context->krb5_context,
  91                              result_code, NULL, &k5_error_bytes,
  92                              NULL, NULL, NULL, NULL, &k5_error_blob);
  93         if (kret) {
  94                 return false;
  95         }
  96         *error_blob = data_blob_talloc(mem_ctx, k5_error_blob.data, k5_error_blob.length);
  97         krb5_data_free(&k5_error_blob);
  98         if (!error_blob->data) {
  99                 return false;
 100         }
 101         return true;
 102 }
 103
 104 static bool kpasswd_make_pwchange_reply(struct kdc_server *kdc,
 105                                         TALLOC_CTX *mem_ctx,
 106                                         NTSTATUS status,
 107                                         enum samPwdChangeReason reject_reason,
 108                                         struct samr_DomInfo1 *dominfo,
 109                                         DATA_BLOB *error_blob)
 110 {
 111         if (NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_USER)) {
 112                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 113                                                 KRB5_KPASSWD_ACCESSDENIED,
 114                                                 "No such user when changing password",
 115                                                 error_blob);
 116         }
 117         if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
 118                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 119                                                 KRB5_KPASSWD_ACCESSDENIED,
 120                                                 "Not permitted to change password",
 121                                                 error_blob);
 122         }
 123         if (dominfo && NT_STATUS_EQUAL(status, NT_STATUS_PASSWORD_RESTRICTION)) {
 124                 const char *reject_string;
 125                 switch (reject_reason) {
 126                 case SAM_PWD_CHANGE_PASSWORD_TOO_SHORT:
 127                         reject_string = talloc_asprintf(mem_ctx, "Password too short, password must be at least %d characters long",
 128                                                         dominfo->min_password_length);
 129                         break;
 130                 case SAM_PWD_CHANGE_NOT_COMPLEX:
 131                         reject_string = "Password does not meet complexity requirements";
 132                         break;
 133                 case SAM_PWD_CHANGE_PWD_IN_HISTORY:
 134                         reject_string = "Password is already in password history";
 135                         break;
 136                 default:
 137                         reject_string = talloc_asprintf(mem_ctx, "Password must be at least %d characters long, and cannot match any of your %d previous passwords",
 138                                                         dominfo->min_password_length, dominfo->password_history_length);
 139                         break;
 140                 }
 141                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 142                                                 KRB5_KPASSWD_SOFTERROR,
 143                                                 reject_string,
 144                                                 error_blob);
 145         }
 146         if (!NT_STATUS_IS_OK(status)) {
 147                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 148                                                  KRB5_KPASSWD_HARDERROR,
 149                                                  talloc_asprintf(mem_ctx, "failed to set password: %s", nt_errstr(status)),
 150                                                  error_blob);
 151
 152         }
 153         return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SUCCESS,
 154                                         "Password changed",
 155                                         error_blob);
 156 }
 157
 158 /*
 159    A user password change
 160
 161    Return true if there is a valid error packet (or sucess) formed in
 162    the error_blob
 163 */
 164 static bool kpasswdd_change_password(struct kdc_server *kdc,
 165                                      TALLOC_CTX *mem_ctx,
 166                                      struct auth_session_info *session_info,
 167                                      const DATA_BLOB *password,
 168                                      DATA_BLOB *reply)
 169 {
 170         NTSTATUS status;
 171         enum samPwdChangeReason reject_reason;
 172         struct samr_DomInfo1 *dominfo;
 173         struct ldb_context *samdb;
 174
 175         samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, system_session(kdc->task->lp_ctx));
 176         if (!samdb) {
 177                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 178                                                 KRB5_KPASSWD_HARDERROR,
 179                                                 "Failed to open samdb",
 180                                                 reply);
 181         }
 182
 183         DEBUG(3, ("Changing password of %s\\%s (%s)\n",
 184                   session_info->server_info->domain_name,
 185                   session_info->server_info->account_name,
 186                   dom_sid_string(mem_ctx, session_info->security_token->user_sid)));
 187
 188         /* User password change */
 189         status = samdb_set_password_sid(samdb, mem_ctx,
 190                                         session_info->security_token->user_sid,
 191                                         password, NULL, NULL,
 192                                         true, /* this is a user password change */
 193                                         &reject_reason,
 194                                         &dominfo);
 195         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 196                                            status,
 197                                            reject_reason,
 198                                            dominfo,
 199                                            reply);
 200
 201 }
 202
 203 static bool kpasswd_process_request(struct kdc_server *kdc,
 204                                     TALLOC_CTX *mem_ctx,
 205                                     struct gensec_security *gensec_security,
 206                                     uint16_t version,
 207                                     DATA_BLOB *input,
 208                                     DATA_BLOB *reply)
 209 {
 210         struct auth_session_info *session_info;
 211         size_t pw_len;
 212
 213         if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security,
 214                                                  &session_info))) {
 215                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 216                                                 KRB5_KPASSWD_HARDERROR,
 217                                                 "gensec_session_info failed!",
 218                                                 reply);
 219         }
 220
 221         switch (version) {
 222         case KRB5_KPASSWD_VERS_CHANGEPW:
 223         {
 224                 DATA_BLOB password;
 225                 if (!convert_string_talloc_convenience(mem_ctx, lp_iconv_convenience(kdc->task->lp_ctx),
 226                                                CH_UTF8, CH_UTF16,
 227                                                (const char *)input->data,
 228                                                input->length,
 229                                                (void **)&password.data, &pw_len, false)) {
 230                         return false;
 231                 }
 232                 password.length = pw_len;
 233
 234                 return kpasswdd_change_password(kdc, mem_ctx, session_info,
 235                                                 &password, reply);
 236                 break;
 237         }
 238         case KRB5_KPASSWD_VERS_SETPW:
 239         {
 240                 NTSTATUS status;
 241                 enum samPwdChangeReason reject_reason = SAM_PWD_CHANGE_NO_ERROR;
 242                 struct samr_DomInfo1 *dominfo = NULL;
 243                 struct ldb_context *samdb;
 244                 struct ldb_message *msg;
 245                 krb5_context context = kdc->smb_krb5_context->krb5_context;
 246
 247                 ChangePasswdDataMS chpw;
 248                 DATA_BLOB password;
 249
 250                 krb5_principal principal;
 251                 char *set_password_on_princ;
 252                 struct ldb_dn *set_password_on_dn;
 253
 254                 size_t len;
 255                 int ret;
 256
 257                 msg = ldb_msg_new(mem_ctx);
 258                 if (!msg) {
 259                         return false;
 260                 }
 261
 262                 ret = decode_ChangePasswdDataMS(input->data, input->length,
 263                                                 &chpw, &len);
 264                 if (ret) {
 265                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 266                                                         KRB5_KPASSWD_MALFORMED,
 267                                                         "failed to decode password change structure",
 268                                                         reply);
 269                 }
 270
 271                 if (!convert_string_talloc_convenience(mem_ctx, lp_iconv_convenience(kdc->task->lp_ctx),
 272                                                CH_UTF8, CH_UTF16,
 273                                                (const char *)chpw.newpasswd.data,
 274                                                chpw.newpasswd.length,
 275                                                (void **)&password.data, &pw_len, false)) {
 276                         free_ChangePasswdDataMS(&chpw);
 277                         return false;
 278                 }
 279
 280                 password.length = pw_len;
 281
 282                 if ((chpw.targname && !chpw.targrealm)
 283                     || (!chpw.targname && chpw.targrealm)) {
 284                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 285                                                         KRB5_KPASSWD_MALFORMED,
 286                                                         "Realm and principal must be both present, or neither present",
 287                                                         reply);
 288                 }
 289                 if (chpw.targname && chpw.targrealm) {
 290 #ifdef SAMBA4_INTERNAL_HEIMDAL
 291                         if (_krb5_principalname2krb5_principal(kdc->smb_krb5_context->krb5_context,
 292                                                                &principal, *chpw.targname,
 293                                                                *chpw.targrealm) != 0) {
 294                                 free_ChangePasswdDataMS(&chpw);
 295                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 296                                                                 KRB5_KPASSWD_MALFORMED,
 297                                                                 "failed to extract principal to set",
 298                                                                 reply);
 299
 300                         }
 301 #else /* SAMBA4_INTERNAL_HEIMDAL */
 302                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 303                                                                 KRB5_KPASSWD_BAD_VERSION,
 304                                                                 "Operation Not Implemented",
 305                                                                 reply);
 306 #endif /* SAMBA4_INTERNAL_HEIMDAL */
 307                 } else {
 308                         free_ChangePasswdDataMS(&chpw);
 309                         return kpasswdd_change_password(kdc, mem_ctx, session_info,
 310                                                         &password, reply);
 311                 }
 312                 free_ChangePasswdDataMS(&chpw);
 313
 314                 if (krb5_unparse_name(context, principal, &set_password_on_princ) != 0) {
 315                         krb5_free_principal(context, principal);
 316                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 317                                                         KRB5_KPASSWD_MALFORMED,
 318                                                         "krb5_unparse_name failed!",
 319                                                         reply);
 320                 }
 321
 322                 krb5_free_principal(context, principal);
 323
 324                 samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, session_info);
 325                 if (!samdb) {
 326                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 327                                                          KRB5_KPASSWD_HARDERROR,
 328                                                          "Unable to open database!",
 329                                                          reply);
 330                 }
 331
 332                 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
 333                           session_info->server_info->domain_name,
 334                           session_info->server_info->account_name,
 335                           dom_sid_string(mem_ctx, session_info->security_token->user_sid),
 336                           set_password_on_princ));
 337                 ret = ldb_transaction_start(samdb);
 338                 if (ret) {
 339                         status = NT_STATUS_TRANSACTION_ABORTED;
 340                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 341                                                            status,
 342                                                            SAM_PWD_CHANGE_NO_ERROR,
 343                                                            NULL,
 344                                                            reply);
 345                 }
 346
 347                 status = crack_user_principal_name(samdb, mem_ctx,
 348                                                    set_password_on_princ,
 349                                                    &set_password_on_dn, NULL);
 350                 free(set_password_on_princ);
 351                 if (!NT_STATUS_IS_OK(status)) {
 352                         ldb_transaction_cancel(samdb);
 353                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 354                                                            status,
 355                                                            SAM_PWD_CHANGE_NO_ERROR,
 356                                                            NULL,
 357                                                            reply);
 358                 }
 359
 360                 msg = ldb_msg_new(mem_ctx);
 361                 if (msg == NULL) {
 362                         ldb_transaction_cancel(samdb);
 363                         status = NT_STATUS_NO_MEMORY;
 364                 } else {
 365                         msg->dn = ldb_dn_copy(msg, set_password_on_dn);
 366                         if (!msg->dn) {
 367                                 status = NT_STATUS_NO_MEMORY;
 368                         }
 369                 }
 370
 371                 if (NT_STATUS_IS_OK(status)) {
 372                         /* Admin password set */
 373                         status = samdb_set_password(samdb, mem_ctx,
 374                                                     set_password_on_dn, NULL,
 375                                                     msg, &password, NULL, NULL,
 376                                                     false, /* this is not a user password change */
 377                                                     &reject_reason, &dominfo);
 378                 }
 379
 380                 if (NT_STATUS_IS_OK(status)) {
 381                         /* modify the samdb record */
 382                         ret = samdb_replace(samdb, mem_ctx, msg);
 383                         if (ret != 0) {
 384                                 DEBUG(2,("Failed to modify record to set password on %s: %s\n",
 385                                          ldb_dn_get_linearized(msg->dn),
 386                                          ldb_errstring(samdb)));
 387                                 status = NT_STATUS_ACCESS_DENIED;
 388                         }
 389                 }
 390                 if (NT_STATUS_IS_OK(status)) {
 391                         ret = ldb_transaction_commit(samdb);
 392                         if (ret != 0) {
 393                                 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
 394                                          ldb_dn_get_linearized(msg->dn),
 395                                          ldb_errstring(samdb)));
 396                                 status = NT_STATUS_TRANSACTION_ABORTED;
 397                         }
 398                 } else {
 399                         ldb_transaction_cancel(samdb);
 400                 }
 401                 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 402                                                    status,
 403                                                    reject_reason,
 404                                                    dominfo,
 405                                                    reply);
 406         }
 407         default:
 408                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 409                                                  KRB5_KPASSWD_BAD_VERSION,
 410                                                  talloc_asprintf(mem_ctx,
 411                                                                  "Protocol version %u not supported",
 412                                                                  version),
 413                                                  reply);
 414         }
 415         return true;
 416 }
 417
 418 bool kpasswdd_process(struct kdc_server *kdc,
 419                       TALLOC_CTX *mem_ctx,
 420                       DATA_BLOB *input,
 421                       DATA_BLOB *reply,
 422                       struct tsocket_address *peer_addr,
 423                       struct tsocket_address *my_addr,
 424                       int datagram_reply)
 425 {
 426         bool ret;
 427         const uint16_t header_len = 6;
 428         uint16_t len;
 429         uint16_t ap_req_len;
 430         uint16_t krb_priv_len;
 431         uint16_t version;
 432         NTSTATUS nt_status;
 433         DATA_BLOB ap_req, krb_priv_req;
 434         DATA_BLOB krb_priv_rep = data_blob(NULL, 0);
 435         DATA_BLOB ap_rep = data_blob(NULL, 0);
 436         DATA_BLOB kpasswd_req, kpasswd_rep;
 437         struct cli_credentials *server_credentials;
 438         struct gensec_security *gensec_security;
 439         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 440
 441         char *keytab_name;
 442
 443         if (!tmp_ctx) {
 444                 return false;
 445         }
 446
 447         /* Be parinoid.  We need to ensure we don't just let the
 448          * caller lead us into a buffer overflow */
 449         if (input->length <= header_len) {
 450                 talloc_free(tmp_ctx);
 451                 return false;
 452         }
 453
 454         len = RSVAL(input->data, 0);
 455         if (input->length != len) {
 456                 talloc_free(tmp_ctx);
 457                 return false;
 458         }
 459
 460         /* There are two different versions of this protocol so far,
 461          * plus others in the standards pipe.  Fortunetly they all
 462          * take a very similar framing */
 463         version = RSVAL(input->data, 2);
 464         ap_req_len = RSVAL(input->data, 4);
 465         if ((ap_req_len >= len) || (ap_req_len + header_len) >= len) {
 466                 talloc_free(tmp_ctx);
 467                 return false;
 468         }
 469
 470         krb_priv_len = len - ap_req_len;
 471         ap_req = data_blob_const(&input->data[header_len], ap_req_len);
 472         krb_priv_req = data_blob_const(&input->data[header_len + ap_req_len], krb_priv_len);
 473
 474         server_credentials = cli_credentials_init(tmp_ctx);
 475         if (!server_credentials) {
 476                 DEBUG(1, ("Failed to init server credentials\n"));
 477                 return false;
 478         }
 479
 480         /* We want the credentials subsystem to use the krb5 context
 481          * we already have, rather than a new context */
 482         cli_credentials_set_krb5_context(server_credentials, kdc->smb_krb5_context);
 483         cli_credentials_set_conf(server_credentials, kdc->task->lp_ctx);
 484
 485         keytab_name = talloc_asprintf(server_credentials, "HDB:samba4&%p", kdc->hdb_samba4_context);
 486
 487         cli_credentials_set_username(server_credentials, "kadmin/changepw", CRED_SPECIFIED);
 488         ret = cli_credentials_set_keytab_name(server_credentials, kdc->task->event_ctx, kdc->task->lp_ctx, keytab_name, CRED_SPECIFIED);
 489         if (ret != 0) {
 490                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 491                                                        KRB5_KPASSWD_HARDERROR,
 492                                                        talloc_asprintf(mem_ctx,
 493                                                                        "Failed to obtain server credentials for kadmin/changepw: %s\n",
 494                                                                        nt_errstr(nt_status)),
 495                                                        &krb_priv_rep);
 496                 ap_rep.length = 0;
 497                 if (ret) {
 498                         goto reply;
 499                 }
 500                 talloc_free(tmp_ctx);
 501                 return ret;
 502         }
 503
 504         /* We don't strictly need to call this wrapper, and could call
 505          * gensec_server_start directly, as we have no need for NTLM
 506          * and we have a PAC, but this ensures that the wrapper can be
 507          * safely extended for other helpful things in future */
 508         nt_status = samba_server_gensec_start(tmp_ctx, kdc->task->event_ctx,
 509                                               kdc->task->msg_ctx,
 510                                               kdc->task->lp_ctx,
 511                                               server_credentials,
 512                                               "kpasswd",
 513                                               &gensec_security);
 514         if (!NT_STATUS_IS_OK(nt_status)) {
 515                 talloc_free(tmp_ctx);
 516                 return false;
 517         }
 518
 519         /* The kerberos PRIV packets include these addresses.  MIT
 520          * clients check that they are present */
 521 #if 0
 522         /* Skip this part for now, it breaks with a NetAPP filer and
 523          * in any case where the client address is behind NAT.  If
 524          * older MIT clients need this, we might have to insert more
 525          * complex code */
 526
 527         nt_status = gensec_set_local_address(gensec_security, peer_addr);
 528         if (!NT_STATUS_IS_OK(nt_status)) {
 529                 talloc_free(tmp_ctx);
 530                 return false;
 531         }
 532 #endif
 533
 534         nt_status = gensec_set_local_address(gensec_security, my_addr);
 535         if (!NT_STATUS_IS_OK(nt_status)) {
 536                 talloc_free(tmp_ctx);
 537                 return false;
 538         }
 539
 540         /* We want the GENSEC wrap calls to generate PRIV tokens */
 541         gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
 542
 543         nt_status = gensec_start_mech_by_name(gensec_security, "krb5");
 544         if (!NT_STATUS_IS_OK(nt_status)) {
 545                 talloc_free(tmp_ctx);
 546                 return false;
 547         }
 548
 549         /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
 550         nt_status = gensec_update(gensec_security, tmp_ctx, ap_req, &ap_rep);
 551         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 552
 553                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 554                                                        KRB5_KPASSWD_HARDERROR,
 555                                                        talloc_asprintf(mem_ctx,
 556                                                                        "gensec_update failed: %s",
 557                                                                        nt_errstr(nt_status)),
 558                                                        &krb_priv_rep);
 559                 ap_rep.length = 0;
 560                 if (ret) {
 561                         goto reply;
 562                 }
 563                 talloc_free(tmp_ctx);
 564                 return ret;
 565         }
 566
 567         /* Extract the data from the KRB-PRIV half of the message */
 568         nt_status = gensec_unwrap(gensec_security, tmp_ctx, &krb_priv_req, &kpasswd_req);
 569         if (!NT_STATUS_IS_OK(nt_status)) {
 570                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 571                                                        KRB5_KPASSWD_HARDERROR,
 572                                                        talloc_asprintf(mem_ctx,
 573                                                                        "gensec_unwrap failed: %s",
 574                                                                        nt_errstr(nt_status)),
 575                                                        &krb_priv_rep);
 576                 ap_rep.length = 0;
 577                 if (ret) {
 578                         goto reply;
 579                 }
 580                 talloc_free(tmp_ctx);
 581                 return ret;
 582         }
 583
 584         /* Figure out something to do with it (probably changing a password...) */
 585         ret = kpasswd_process_request(kdc, tmp_ctx,
 586                                       gensec_security,
 587                                       version,
 588                                       &kpasswd_req, &kpasswd_rep);
 589         if (!ret) {
 590                 /* Argh! */
 591                 return false;
 592         }
 593
 594         /* And wrap up the reply: This ensures that the error message
 595          * or success can be verified by the client */
 596         nt_status = gensec_wrap(gensec_security, tmp_ctx,
 597                                 &kpasswd_rep, &krb_priv_rep);
 598         if (!NT_STATUS_IS_OK(nt_status)) {
 599                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 600                                                        KRB5_KPASSWD_HARDERROR,
 601                                                        talloc_asprintf(mem_ctx,
 602                                                                        "gensec_wrap failed: %s",
 603                                                                        nt_errstr(nt_status)),
 604                                                        &krb_priv_rep);
 605                 ap_rep.length = 0;
 606                 if (ret) {
 607                         goto reply;
 608                 }
 609                 talloc_free(tmp_ctx);
 610                 return ret;
 611         }
 612
 613 reply:
 614         *reply = data_blob_talloc(mem_ctx, NULL, krb_priv_rep.length + ap_rep.length + header_len);
 615         if (!reply->data) {
 616                 return false;
 617         }
 618
 619         RSSVAL(reply->data, 0, reply->length);
 620         RSSVAL(reply->data, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
 621         RSSVAL(reply->data, 4, ap_rep.length);
 622         memcpy(reply->data + header_len,
 623                ap_rep.data,
 624                ap_rep.length);
 625         memcpy(reply->data + header_len + ap_rep.length,
 626                krb_priv_rep.data,
 627                krb_priv_rep.length);
 628
 629         talloc_free(tmp_ctx);
 630         return ret;
 631 }
 632