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 samPwdChangeReason 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 SAM_PWD_CHANGE_PASSWORD_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 SAM_PWD_CHANGE_NOT_COMPLEX:
 140                         reject_string = "Password does not meet complexity requirements";
 141                         break;
 142                 case SAM_PWD_CHANGE_PWD_IN_HISTORY:
 143                         reject_string = "Password is already in password history";
 144                         break;
 145                 default:
 146                         reject_string = talloc_asprintf(mem_ctx, "Password must be at least %d characters long, and cannot match any of your %d previous passwords",
 147                                                         dominfo->min_password_length, dominfo->password_history_length);
 148                         break;
 149                 }
 150                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 151                                                 KRB5_KPASSWD_SOFTERROR,
 152                                                 reject_string,
 153                                                 error_blob);
 154         }
 155         if (!NT_STATUS_IS_OK(status)) {
 156                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 157                                                  KRB5_KPASSWD_HARDERROR,
 158                                                  talloc_asprintf(mem_ctx, "failed to set password: %s", nt_errstr(status)),
 159                                                  error_blob);
 160
 161         }
 162         return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SUCCESS,
 163                                         "Password changed",
 164                                         error_blob);
 165 }
 166
 167 /*
 168    A user password change
 169
 170    Return true if there is a valid error packet (or sucess) formed in
 171    the error_blob
 172 */
 173 static bool kpasswdd_change_password(struct kdc_server *kdc,
 174                                      TALLOC_CTX *mem_ctx,
 175                                      struct auth_session_info *session_info,
 176                                      const DATA_BLOB *password,
 177                                      DATA_BLOB *reply)
 178 {
 179         NTSTATUS status;
 180         enum samPwdChangeReason reject_reason;
 181         struct samr_DomInfo1 *dominfo;
 182         struct ldb_context *samdb;
 183
 184         samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, system_session(mem_ctx, kdc->task->lp_ctx));
 185         if (!samdb) {
 186                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 187                                                 KRB5_KPASSWD_HARDERROR,
 188                                                 "Failed to open samdb",
 189                                                 reply);
 190         }
 191
 192         DEBUG(3, ("Changing password of %s\\%s (%s)\n",
 193                   session_info->server_info->domain_name,
 194                   session_info->server_info->account_name,
 195                   dom_sid_string(mem_ctx, session_info->security_token->user_sid)));
 196
 197         /* User password change */
 198         status = samdb_set_password_sid(samdb, mem_ctx,
 199                                         session_info->security_token->user_sid,
 200                                         password, NULL, NULL,
 201                                         true, /* this is a user password change */
 202                                         &reject_reason,
 203                                         &dominfo);
 204         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 205                                            status,
 206                                            reject_reason,
 207                                            dominfo,
 208                                            reply);
 209
 210 }
 211
 212 static bool kpasswd_process_request(struct kdc_server *kdc,
 213                                     TALLOC_CTX *mem_ctx,
 214                                     struct gensec_security *gensec_security,
 215                                     uint16_t version,
 216                                     DATA_BLOB *input,
 217                                     DATA_BLOB *reply)
 218 {
 219         struct auth_session_info *session_info;
 220         size_t pw_len;
 221
 222         if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security,
 223                                                  &session_info))) {
 224                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 225                                                 KRB5_KPASSWD_HARDERROR,
 226                                                 "gensec_session_info failed!",
 227                                                 reply);
 228         }
 229
 230         switch (version) {
 231         case KRB5_KPASSWD_VERS_CHANGEPW:
 232         {
 233                 DATA_BLOB password;
 234                 if (!convert_string_talloc_convenience(mem_ctx, lp_iconv_convenience(kdc->task->lp_ctx),
 235                                                CH_UTF8, CH_UTF16,
 236                                                (const char *)input->data,
 237                                                input->length,
 238                                                (void **)&password.data, &pw_len, false)) {
 239                         return false;
 240                 }
 241                 password.length = pw_len;
 242
 243                 return kpasswdd_change_password(kdc, mem_ctx, session_info,
 244                                                 &password, reply);
 245                 break;
 246         }
 247         case KRB5_KPASSWD_VERS_SETPW:
 248         {
 249                 NTSTATUS status;
 250                 enum samPwdChangeReason reject_reason = SAM_PWD_CHANGE_NO_ERROR;
 251                 struct samr_DomInfo1 *dominfo = NULL;
 252                 struct ldb_context *samdb;
 253                 struct ldb_message *msg;
 254                 krb5_context context = kdc->smb_krb5_context->krb5_context;
 255
 256                 ChangePasswdDataMS chpw;
 257                 DATA_BLOB password;
 258
 259                 krb5_principal principal;
 260                 char *set_password_on_princ;
 261                 struct ldb_dn *set_password_on_dn;
 262
 263                 size_t len;
 264                 int ret;
 265
 266                 msg = ldb_msg_new(mem_ctx);
 267                 if (!msg) {
 268                         return false;
 269                 }
 270
 271                 ret = decode_ChangePasswdDataMS(input->data, input->length,
 272                                                 &chpw, &len);
 273                 if (ret) {
 274                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 275                                                         KRB5_KPASSWD_MALFORMED,
 276                                                         "failed to decode password change structure",
 277                                                         reply);
 278                 }
 279
 280                 if (!convert_string_talloc_convenience(mem_ctx, lp_iconv_convenience(kdc->task->lp_ctx),
 281                                                CH_UTF8, CH_UTF16,
 282                                                (const char *)chpw.newpasswd.data,
 283                                                chpw.newpasswd.length,
 284                                                (void **)&password.data, &pw_len, false)) {
 285                         free_ChangePasswdDataMS(&chpw);
 286                         return false;
 287                 }
 288
 289                 password.length = pw_len;
 290
 291                 if ((chpw.targname && !chpw.targrealm)
 292                     || (!chpw.targname && chpw.targrealm)) {
 293                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 294                                                         KRB5_KPASSWD_MALFORMED,
 295                                                         "Realm and principal must be both present, or neither present",
 296                                                         reply);
 297                 }
 298                 if (chpw.targname && chpw.targrealm) {
 299 #ifdef SAMBA4_INTERNAL_HEIMDAL
 300                         if (_krb5_principalname2krb5_principal(kdc->smb_krb5_context->krb5_context,
 301                                                                &principal, *chpw.targname,
 302                                                                *chpw.targrealm) != 0) {
 303                                 free_ChangePasswdDataMS(&chpw);
 304                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 305                                                                 KRB5_KPASSWD_MALFORMED,
 306                                                                 "failed to extract principal to set",
 307                                                                 reply);
 308
 309                         }
 310 #else /* SAMBA4_INTERNAL_HEIMDAL */
 311                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 312                                                                 KRB5_KPASSWD_BAD_VERSION,
 313                                                                 "Operation Not Implemented",
 314                                                                 reply);
 315 #endif /* SAMBA4_INTERNAL_HEIMDAL */
 316                 } else {
 317                         free_ChangePasswdDataMS(&chpw);
 318                         return kpasswdd_change_password(kdc, mem_ctx, session_info,
 319                                                         &password, reply);
 320                 }
 321                 free_ChangePasswdDataMS(&chpw);
 322
 323                 if (krb5_unparse_name(context, principal, &set_password_on_princ) != 0) {
 324                         krb5_free_principal(context, principal);
 325                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 326                                                         KRB5_KPASSWD_MALFORMED,
 327                                                         "krb5_unparse_name failed!",
 328                                                         reply);
 329                 }
 330
 331                 krb5_free_principal(context, principal);
 332
 333                 samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, session_info);
 334                 if (!samdb) {
 335                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 336                                                          KRB5_KPASSWD_HARDERROR,
 337                                                          "Unable to open database!",
 338                                                          reply);
 339                 }
 340
 341                 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
 342                           session_info->server_info->domain_name,
 343                           session_info->server_info->account_name,
 344                           dom_sid_string(mem_ctx, session_info->security_token->user_sid),
 345                           set_password_on_princ));
 346                 ret = ldb_transaction_start(samdb);
 347                 if (ret) {
 348                         status = NT_STATUS_TRANSACTION_ABORTED;
 349                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 350                                                            status,
 351                                                            SAM_PWD_CHANGE_NO_ERROR,
 352                                                            NULL,
 353                                                            reply);
 354                 }
 355
 356                 status = crack_user_principal_name(samdb, mem_ctx,
 357                                                    set_password_on_princ,
 358                                                    &set_password_on_dn, NULL);
 359                 free(set_password_on_princ);
 360                 if (!NT_STATUS_IS_OK(status)) {
 361                         ldb_transaction_cancel(samdb);
 362                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 363                                                            status,
 364                                                            SAM_PWD_CHANGE_NO_ERROR,
 365                                                            NULL,
 366                                                            reply);
 367                 }
 368
 369                 msg = ldb_msg_new(mem_ctx);
 370                 if (msg == NULL) {
 371                         ldb_transaction_cancel(samdb);
 372                         status = NT_STATUS_NO_MEMORY;
 373                 } else {
 374                         msg->dn = ldb_dn_copy(msg, set_password_on_dn);
 375                         if (!msg->dn) {
 376                                 status = NT_STATUS_NO_MEMORY;
 377                         }
 378                 }
 379
 380                 if (NT_STATUS_IS_OK(status)) {
 381                         /* Admin password set */
 382                         status = samdb_set_password(samdb, mem_ctx,
 383                                                     set_password_on_dn, NULL,
 384                                                     msg, &password, NULL, NULL,
 385                                                     false, /* this is not a user password change */
 386                                                     &reject_reason, &dominfo);
 387                 }
 388
 389                 if (NT_STATUS_IS_OK(status)) {
 390                         /* modify the samdb record */
 391                         ret = samdb_replace(samdb, mem_ctx, msg);
 392                         if (ret != 0) {
 393                                 DEBUG(2,("Failed to modify record to set password on %s: %s\n",
 394                                          ldb_dn_get_linearized(msg->dn),
 395                                          ldb_errstring(samdb)));
 396                                 status = NT_STATUS_ACCESS_DENIED;
 397                         }
 398                 }
 399                 if (NT_STATUS_IS_OK(status)) {
 400                         ret = ldb_transaction_commit(samdb);
 401                         if (ret != 0) {
 402                                 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
 403                                          ldb_dn_get_linearized(msg->dn),
 404                                          ldb_errstring(samdb)));
 405                                 status = NT_STATUS_TRANSACTION_ABORTED;
 406                         }
 407                 } else {
 408                         ldb_transaction_cancel(samdb);
 409                 }
 410                 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 411                                                    status,
 412                                                    reject_reason,
 413                                                    dominfo,
 414                                                    reply);
 415         }
 416         default:
 417                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 418                                                  KRB5_KPASSWD_BAD_VERSION,
 419                                                  talloc_asprintf(mem_ctx,
 420                                                                  "Protocol version %u not supported",
 421                                                                  version),
 422                                                  reply);
 423         }
 424         return true;
 425 }
 426
 427 bool kpasswdd_process(struct kdc_server *kdc,
 428                       TALLOC_CTX *mem_ctx,
 429                       DATA_BLOB *input,
 430                       DATA_BLOB *reply,
 431                       struct socket_address *peer_addr,
 432                       struct socket_address *my_addr,
 433                       int datagram_reply)
 434 {
 435         bool ret;
 436         const uint16_t header_len = 6;
 437         uint16_t len;
 438         uint16_t ap_req_len;
 439         uint16_t krb_priv_len;
 440         uint16_t version;
 441         NTSTATUS nt_status;
 442         DATA_BLOB ap_req, krb_priv_req;
 443         DATA_BLOB krb_priv_rep = data_blob(NULL, 0);
 444         DATA_BLOB ap_rep = data_blob(NULL, 0);
 445         DATA_BLOB kpasswd_req, kpasswd_rep;
 446         struct cli_credentials *server_credentials;
 447         struct gensec_security *gensec_security;
 448         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 449
 450         char *keytab_name;
 451
 452         if (!tmp_ctx) {
 453                 return false;
 454         }
 455
 456         /* Be parinoid.  We need to ensure we don't just let the
 457          * caller lead us into a buffer overflow */
 458         if (input->length <= header_len) {
 459                 talloc_free(tmp_ctx);
 460                 return false;
 461         }
 462
 463         len = RSVAL(input->data, 0);
 464         if (input->length != len) {
 465                 talloc_free(tmp_ctx);
 466                 return false;
 467         }
 468
 469         /* There are two different versions of this protocol so far,
 470          * plus others in the standards pipe.  Fortunetly they all
 471          * take a very similar framing */
 472         version = RSVAL(input->data, 2);
 473         ap_req_len = RSVAL(input->data, 4);
 474         if ((ap_req_len >= len) || (ap_req_len + header_len) >= len) {
 475                 talloc_free(tmp_ctx);
 476                 return false;
 477         }
 478
 479         krb_priv_len = len - ap_req_len;
 480         ap_req = data_blob_const(&input->data[header_len], ap_req_len);
 481         krb_priv_req = data_blob_const(&input->data[header_len + ap_req_len], krb_priv_len);
 482
 483         server_credentials = cli_credentials_init(tmp_ctx);
 484         if (!server_credentials) {
 485                 DEBUG(1, ("Failed to init server credentials\n"));
 486                 return false;
 487         }
 488
 489         /* We want the credentials subsystem to use the krb5 context
 490          * we already have, rather than a new context */
 491         cli_credentials_set_krb5_context(server_credentials, kdc->smb_krb5_context);
 492         cli_credentials_set_conf(server_credentials, kdc->task->lp_ctx);
 493
 494         keytab_name = talloc_asprintf(server_credentials, "HDB:samba4&%p", kdc->hdb_samba4_context);
 495
 496         cli_credentials_set_username(server_credentials, "kadmin/changepw", CRED_SPECIFIED);
 497         ret = cli_credentials_set_keytab_name(server_credentials, kdc->task->event_ctx, kdc->task->lp_ctx, keytab_name, CRED_SPECIFIED);
 498         if (ret != 0) {
 499                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 500                                                        KRB5_KPASSWD_HARDERROR,
 501                                                        talloc_asprintf(mem_ctx,
 502                                                                        "Failed to obtain server credentials for kadmin/changepw: %s\n",
 503                                                                        nt_errstr(nt_status)),
 504                                                        &krb_priv_rep);
 505                 ap_rep.length = 0;
 506                 if (ret) {
 507                         goto reply;
 508                 }
 509                 talloc_free(tmp_ctx);
 510                 return ret;
 511         }
 512
 513         /* We don't strictly need to call this wrapper, and could call
 514          * gensec_server_start directly, as we have no need for NTLM
 515          * and we have a PAC, but this ensures that the wrapper can be
 516          * safely extended for other helpful things in future */
 517         nt_status = samba_server_gensec_start(tmp_ctx, kdc->task->event_ctx,
 518                                               kdc->task->msg_ctx,
 519                                               kdc->task->lp_ctx,
 520                                               server_credentials,
 521                                               "kpasswd",
 522                                               &gensec_security);
 523         if (!NT_STATUS_IS_OK(nt_status)) {
 524                 talloc_free(tmp_ctx);
 525                 return false;
 526         }
 527
 528         /* The kerberos PRIV packets include these addresses.  MIT
 529          * clients check that they are present */
 530 #if 0
 531         /* Skip this part for now, it breaks with a NetAPP filer and
 532          * in any case where the client address is behind NAT.  If
 533          * older MIT clients need this, we might have to insert more
 534          * complex code */
 535
 536         nt_status = gensec_set_peer_addr(gensec_security, peer_addr);
 537         if (!NT_STATUS_IS_OK(nt_status)) {
 538                 talloc_free(tmp_ctx);
 539                 return false;
 540         }
 541 #endif
 542
 543         nt_status = gensec_set_my_addr(gensec_security, my_addr);
 544         if (!NT_STATUS_IS_OK(nt_status)) {
 545                 talloc_free(tmp_ctx);
 546                 return false;
 547         }
 548
 549         /* We want the GENSEC wrap calls to generate PRIV tokens */
 550         gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
 551
 552         nt_status = gensec_start_mech_by_name(gensec_security, "krb5");
 553         if (!NT_STATUS_IS_OK(nt_status)) {
 554                 talloc_free(tmp_ctx);
 555                 return false;
 556         }
 557
 558         /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
 559         nt_status = gensec_update(gensec_security, tmp_ctx, ap_req, &ap_rep);
 560         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 561
 562                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 563                                                        KRB5_KPASSWD_HARDERROR,
 564                                                        talloc_asprintf(mem_ctx,
 565                                                                        "gensec_update failed: %s",
 566                                                                        nt_errstr(nt_status)),
 567                                                        &krb_priv_rep);
 568                 ap_rep.length = 0;
 569                 if (ret) {
 570                         goto reply;
 571                 }
 572                 talloc_free(tmp_ctx);
 573                 return ret;
 574         }
 575
 576         /* Extract the data from the KRB-PRIV half of the message */
 577         nt_status = gensec_unwrap(gensec_security, tmp_ctx, &krb_priv_req, &kpasswd_req);
 578         if (!NT_STATUS_IS_OK(nt_status)) {
 579                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 580                                                        KRB5_KPASSWD_HARDERROR,
 581                                                        talloc_asprintf(mem_ctx,
 582                                                                        "gensec_unwrap failed: %s",
 583                                                                        nt_errstr(nt_status)),
 584                                                        &krb_priv_rep);
 585                 ap_rep.length = 0;
 586                 if (ret) {
 587                         goto reply;
 588                 }
 589                 talloc_free(tmp_ctx);
 590                 return ret;
 591         }
 592
 593         /* Figure out something to do with it (probably changing a password...) */
 594         ret = kpasswd_process_request(kdc, tmp_ctx,
 595                                       gensec_security,
 596                                       version,
 597                                       &kpasswd_req, &kpasswd_rep);
 598         if (!ret) {
 599                 /* Argh! */
 600                 return false;
 601         }
 602
 603         /* And wrap up the reply: This ensures that the error message
 604          * or success can be verified by the client */
 605         nt_status = gensec_wrap(gensec_security, tmp_ctx,
 606                                 &kpasswd_rep, &krb_priv_rep);
 607         if (!NT_STATUS_IS_OK(nt_status)) {
 608                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 609                                                        KRB5_KPASSWD_HARDERROR,
 610                                                        talloc_asprintf(mem_ctx,
 611                                                                        "gensec_wrap failed: %s",
 612                                                                        nt_errstr(nt_status)),
 613                                                        &krb_priv_rep);
 614                 ap_rep.length = 0;
 615                 if (ret) {
 616                         goto reply;
 617                 }
 618                 talloc_free(tmp_ctx);
 619                 return ret;
 620         }
 621
 622 reply:
 623         *reply = data_blob_talloc(mem_ctx, NULL, krb_priv_rep.length + ap_rep.length + header_len);
 624         if (!reply->data) {
 625                 return false;
 626         }
 627
 628         RSSVAL(reply->data, 0, reply->length);
 629         RSSVAL(reply->data, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
 630         RSSVAL(reply->data, 4, ap_rep.length);
 631         memcpy(reply->data + header_len,
 632                ap_rep.data,
 633                ap_rep.length);
 634         memcpy(reply->data + header_len + ap_rep.length,
 635                krb_priv_rep.data,
 636                krb_priv_rep.length);
 637
 638         talloc_free(tmp_ctx);
 639         return ret;
 640 }
 641