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 "auth/gensec/gensec.h"
  26 #include "auth/credentials/credentials.h"
  27 #include "auth/auth.h"
  28 #include "dsdb/samdb/samdb.h"
  29 #include "../lib/util/util_ldb.h"
  30 #include "libcli/security/security.h"
  31 #include "param/param.h"
  32 #include "kdc/kdc-glue.h"
  33
  34 /* Return true if there is a valid error packet formed in the error_blob */
  35 static bool kpasswdd_make_error_reply(struct kdc_server *kdc,
  36                                      TALLOC_CTX *mem_ctx,
  37                                      uint16_t result_code,
  38                                      const char *error_string,
  39                                      DATA_BLOB *error_blob)
  40 {
  41         char *error_string_utf8;
  42         size_t len;
  43
  44         DEBUG(result_code ? 3 : 10, ("kpasswdd: %s\n", error_string));
  45
  46         if (!push_utf8_talloc(mem_ctx, &error_string_utf8, error_string, &len)) {
  47                 return false;
  48         }
  49
  50         *error_blob = data_blob_talloc(mem_ctx, NULL, 2 + len + 1);
  51         if (!error_blob->data) {
  52                 return false;
  53         }
  54         RSSVAL(error_blob->data, 0, result_code);
  55         memcpy(error_blob->data + 2, error_string_utf8, len + 1);
  56         return true;
  57 }
  58
  59 /* Return true if there is a valid error packet formed in the error_blob */
  60 static bool kpasswdd_make_unauth_error_reply(struct kdc_server *kdc,
  61                                             TALLOC_CTX *mem_ctx,
  62                                             uint16_t result_code,
  63                                             const char *error_string,
  64                                             DATA_BLOB *error_blob)
  65 {
  66         bool ret;
  67         int kret;
  68         DATA_BLOB error_bytes;
  69         krb5_data k5_error_bytes, k5_error_blob;
  70         ret = kpasswdd_make_error_reply(kdc, mem_ctx, result_code, error_string,
  71                                        &error_bytes);
  72         if (!ret) {
  73                 return false;
  74         }
  75         k5_error_bytes.data = error_bytes.data;
  76         k5_error_bytes.length = error_bytes.length;
  77         kret = krb5_mk_error(kdc->smb_krb5_context->krb5_context,
  78                              result_code, NULL, &k5_error_bytes,
  79                              NULL, NULL, NULL, NULL, &k5_error_blob);
  80         if (kret) {
  81                 return false;
  82         }
  83         *error_blob = data_blob_talloc(mem_ctx, k5_error_blob.data, k5_error_blob.length);
  84         krb5_data_free(&k5_error_blob);
  85         if (!error_blob->data) {
  86                 return false;
  87         }
  88         return true;
  89 }
  90
  91 static bool kpasswd_make_pwchange_reply(struct kdc_server *kdc,
  92                                         TALLOC_CTX *mem_ctx,
  93                                         NTSTATUS status,
  94                                         enum samPwdChangeReason reject_reason,
  95                                         struct samr_DomInfo1 *dominfo,
  96                                         DATA_BLOB *error_blob)
  97 {
  98         if (NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_USER)) {
  99                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 100                                                 KRB5_KPASSWD_ACCESSDENIED,
 101                                                 "No such user when changing password",
 102                                                 error_blob);
 103         }
 104         if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
 105                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 106                                                 KRB5_KPASSWD_ACCESSDENIED,
 107                                                 "Not permitted to change password",
 108                                                 error_blob);
 109         }
 110         if (dominfo && NT_STATUS_EQUAL(status, NT_STATUS_PASSWORD_RESTRICTION)) {
 111                 const char *reject_string;
 112                 switch (reject_reason) {
 113                 case SAM_PWD_CHANGE_PASSWORD_TOO_SHORT:
 114                         reject_string = talloc_asprintf(mem_ctx, "Password too short, password must be at least %d characters long",
 115                                                         dominfo->min_password_length);
 116                         break;
 117                 case SAM_PWD_CHANGE_NOT_COMPLEX:
 118                         reject_string = "Password does not meet complexity requirements";
 119                         break;
 120                 case SAM_PWD_CHANGE_PWD_IN_HISTORY:
 121                         reject_string = "Password is already in password history";
 122                         break;
 123                 default:
 124                         reject_string = talloc_asprintf(mem_ctx, "Password must be at least %d characters long, and cannot match any of your %d previous passwords",
 125                                                         dominfo->min_password_length, dominfo->password_history_length);
 126                         break;
 127                 }
 128                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 129                                                 KRB5_KPASSWD_SOFTERROR,
 130                                                 reject_string,
 131                                                 error_blob);
 132         }
 133         if (!NT_STATUS_IS_OK(status)) {
 134                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 135                                                  KRB5_KPASSWD_HARDERROR,
 136                                                  talloc_asprintf(mem_ctx, "failed to set password: %s", nt_errstr(status)),
 137                                                  error_blob);
 138
 139         }
 140         return kpasswdd_make_error_reply(kdc, mem_ctx, KRB5_KPASSWD_SUCCESS,
 141                                         "Password changed",
 142                                         error_blob);
 143 }
 144
 145 /*
 146    A user password change
 147
 148    Return true if there is a valid error packet (or success) formed in
 149    the error_blob
 150 */
 151 static bool kpasswdd_change_password(struct kdc_server *kdc,
 152                                      TALLOC_CTX *mem_ctx,
 153                                      struct auth_session_info *session_info,
 154                                      const DATA_BLOB *password,
 155                                      DATA_BLOB *reply)
 156 {
 157         NTSTATUS status;
 158         enum samPwdChangeReason reject_reason;
 159         struct samr_DomInfo1 *dominfo;
 160         struct samr_Password *oldLmHash, *oldNtHash;
 161         struct ldb_context *samdb;
 162         const char * const attrs[] = { "dBCSPwd", "unicodePwd", NULL };
 163         struct ldb_message **res;
 164         int ret;
 165
 166         /* Fetch the old hashes to get the old password in order to perform
 167          * the password change operation. Naturally it would be much better to
 168          * have a password hash from an authentication around but this doesn't
 169          * seem to be the case here. */
 170         ret = gendb_search(kdc->samdb, mem_ctx, NULL, &res, attrs,
 171                            "(&(objectClass=user)(sAMAccountName=%s))",
 172                            session_info->info->account_name);
 173         if (ret != 1) {
 174                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 175                                                 KRB5_KPASSWD_ACCESSDENIED,
 176                                                 "No such user when changing password",
 177                                                 reply);
 178         }
 179
 180         status = samdb_result_passwords(mem_ctx, kdc->task->lp_ctx, res[0],
 181                                         &oldLmHash, &oldNtHash);
 182         if (!NT_STATUS_IS_OK(status)) {
 183                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 184                                                 KRB5_KPASSWD_ACCESSDENIED,
 185                                                 "Not permitted to change password",
 186                                                 reply);
 187         }
 188
 189         /* Start a SAM with user privileges for the password change */
 190         samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx,
 191                               session_info, 0);
 192         if (!samdb) {
 193                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 194                                                 KRB5_KPASSWD_HARDERROR,
 195                                                 "Failed to open samdb",
 196                                                 reply);
 197         }
 198
 199         DEBUG(3, ("Changing password of %s\\%s (%s)\n",
 200                   session_info->info->domain_name,
 201                   session_info->info->account_name,
 202                   dom_sid_string(mem_ctx, &session_info->security_token->sids[PRIMARY_USER_SID_INDEX])));
 203
 204         /* Performs the password change */
 205         status = samdb_set_password_sid(samdb, mem_ctx,
 206                                         &session_info->security_token->sids[PRIMARY_USER_SID_INDEX],
 207                                         password, NULL, NULL,
 208                                         oldLmHash, oldNtHash, /* this is a user password change */
 209                                         &reject_reason,
 210                                         &dominfo);
 211         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 212                                            status,
 213                                            reject_reason,
 214                                            dominfo,
 215                                            reply);
 216
 217 }
 218
 219 static bool kpasswd_process_request(struct kdc_server *kdc,
 220                                     TALLOC_CTX *mem_ctx,
 221                                     struct gensec_security *gensec_security,
 222                                     uint16_t version,
 223                                     DATA_BLOB *input,
 224                                     DATA_BLOB *reply)
 225 {
 226         struct auth_session_info *session_info;
 227         size_t pw_len;
 228
 229         if (!NT_STATUS_IS_OK(gensec_session_info(gensec_security,
 230                                                  &session_info))) {
 231                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 232                                                 KRB5_KPASSWD_HARDERROR,
 233                                                 "gensec_session_info failed!",
 234                                                 reply);
 235         }
 236
 237         switch (version) {
 238         case KRB5_KPASSWD_VERS_CHANGEPW:
 239         {
 240                 DATA_BLOB password;
 241                 if (!convert_string_talloc_convenience(mem_ctx, lpcfg_iconv_convenience(kdc->task->lp_ctx),
 242                                                CH_UTF8, CH_UTF16,
 243                                                (const char *)input->data,
 244                                                input->length,
 245                                                (void **)&password.data, &pw_len, false)) {
 246                         return false;
 247                 }
 248                 password.length = pw_len;
 249
 250                 return kpasswdd_change_password(kdc, mem_ctx, session_info,
 251                                                 &password, reply);
 252         }
 253         case KRB5_KPASSWD_VERS_SETPW:
 254         {
 255                 NTSTATUS status;
 256                 enum samPwdChangeReason reject_reason = SAM_PWD_CHANGE_NO_ERROR;
 257                 struct samr_DomInfo1 *dominfo = NULL;
 258                 struct ldb_context *samdb;
 259                 krb5_context context = kdc->smb_krb5_context->krb5_context;
 260
 261                 ChangePasswdDataMS chpw;
 262                 DATA_BLOB password;
 263
 264                 krb5_principal principal;
 265                 char *set_password_on_princ;
 266                 struct ldb_dn *set_password_on_dn;
 267                 bool service_principal_name = false;
 268
 269                 size_t len;
 270                 int ret;
 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, lpcfg_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                         free_ChangePasswdDataMS(&chpw);
 295                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 296                                                         KRB5_KPASSWD_MALFORMED,
 297                                                         "Realm and principal must be both present, or neither present",
 298                                                         reply);
 299                 }
 300                 if (chpw.targname && chpw.targrealm) {
 301                         ret = krb5_build_principal_ext(kdc->smb_krb5_context->krb5_context,
 302                                                        &principal,
 303                                                        strlen(*chpw.targrealm),
 304                                                        *chpw.targrealm, 0);
 305                         if (ret) {
 306                                 free_ChangePasswdDataMS(&chpw);
 307                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 308                                                                 KRB5_KPASSWD_MALFORMED,
 309                                                                 "failed to get principal",
 310                                                                 reply);
 311                         }
 312                         if (copy_PrincipalName(chpw.targname, &principal->name)) {
 313                                 free_ChangePasswdDataMS(&chpw);
 314                                 krb5_free_principal(context, principal);
 315                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 316                                                                 KRB5_KPASSWD_MALFORMED,
 317                                                                 "failed to extract principal to set",
 318                                                                 reply);
 319                         }
 320                 } else {
 321                         free_ChangePasswdDataMS(&chpw);
 322                         return kpasswdd_change_password(kdc, mem_ctx, session_info,
 323                                                         &password, reply);
 324                 }
 325                 free_ChangePasswdDataMS(&chpw);
 326
 327                 if (principal->name.name_string.len >= 2) {
 328                         service_principal_name = true;
 329
 330                         /* We use this, rather than 'no realm' flag,
 331                          * as we don't want to accept a password
 332                          * change on a principal from another realm */
 333
 334                         if (krb5_unparse_name_short(context, principal, &set_password_on_princ) != 0) {
 335                                 krb5_free_principal(context, principal);
 336                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 337                                                                  KRB5_KPASSWD_MALFORMED,
 338                                                                  "krb5_unparse_name failed!",
 339                                                                  reply);
 340                         }
 341                 } else {
 342                         if (krb5_unparse_name(context, principal, &set_password_on_princ) != 0) {
 343                                 krb5_free_principal(context, principal);
 344                                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 345                                                                  KRB5_KPASSWD_MALFORMED,
 346                                                                  "krb5_unparse_name failed!",
 347                                                                  reply);
 348                         }
 349                 }
 350                 krb5_free_principal(context, principal);
 351
 352                 samdb = samdb_connect(mem_ctx, kdc->task->event_ctx, kdc->task->lp_ctx, session_info, 0);
 353                 if (!samdb) {
 354                         free(set_password_on_princ);
 355                         return kpasswdd_make_error_reply(kdc, mem_ctx,
 356                                                          KRB5_KPASSWD_HARDERROR,
 357                                                          "Unable to open database!",
 358                                                          reply);
 359                 }
 360
 361                 DEBUG(3, ("%s\\%s (%s) is changing password of %s\n",
 362                           session_info->info->domain_name,
 363                           session_info->info->account_name,
 364                           dom_sid_string(mem_ctx, &session_info->security_token->sids[PRIMARY_USER_SID_INDEX]),
 365                           set_password_on_princ));
 366                 ret = ldb_transaction_start(samdb);
 367                 if (ret != LDB_SUCCESS) {
 368                         free(set_password_on_princ);
 369                         status = NT_STATUS_TRANSACTION_ABORTED;
 370                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 371                                                            status,
 372                                                            SAM_PWD_CHANGE_NO_ERROR,
 373                                                            NULL,
 374                                                            reply);
 375                 }
 376
 377                 if (service_principal_name) {
 378                         status = crack_service_principal_name(samdb, mem_ctx,
 379                                                               set_password_on_princ,
 380                                                               &set_password_on_dn, NULL);
 381                 } else {
 382                         status = crack_user_principal_name(samdb, mem_ctx,
 383                                                            set_password_on_princ,
 384                                                            &set_password_on_dn, NULL);
 385                 }
 386                 free(set_password_on_princ);
 387                 if (!NT_STATUS_IS_OK(status)) {
 388                         ldb_transaction_cancel(samdb);
 389                         return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 390                                                            status,
 391                                                            SAM_PWD_CHANGE_NO_ERROR,
 392                                                            NULL,
 393                                                            reply);
 394                 }
 395
 396                 if (NT_STATUS_IS_OK(status)) {
 397                         /* Admin password set */
 398                         status = samdb_set_password(samdb, mem_ctx,
 399                                                     set_password_on_dn, NULL,
 400                                                     &password, NULL, NULL,
 401                                                     NULL, NULL, /* this is not a user password change */
 402                                                     &reject_reason, &dominfo);
 403                 }
 404
 405                 if (NT_STATUS_IS_OK(status)) {
 406                         ret = ldb_transaction_commit(samdb);
 407                         if (ret != LDB_SUCCESS) {
 408                                 DEBUG(1,("Failed to commit transaction to set password on %s: %s\n",
 409                                          ldb_dn_get_linearized(set_password_on_dn),
 410                                          ldb_errstring(samdb)));
 411                                 status = NT_STATUS_TRANSACTION_ABORTED;
 412                         }
 413                 } else {
 414                         ldb_transaction_cancel(samdb);
 415                 }
 416                 return kpasswd_make_pwchange_reply(kdc, mem_ctx,
 417                                                    status,
 418                                                    reject_reason,
 419                                                    dominfo,
 420                                                    reply);
 421         }
 422         default:
 423                 return kpasswdd_make_error_reply(kdc, mem_ctx,
 424                                                  KRB5_KPASSWD_BAD_VERSION,
 425                                                  talloc_asprintf(mem_ctx,
 426                                                                  "Protocol version %u not supported",
 427                                                                  version),
 428                                                  reply);
 429         }
 430 }
 431
 432 enum kdc_process_ret kpasswdd_process(struct kdc_server *kdc,
 433                                       TALLOC_CTX *mem_ctx,
 434                                       DATA_BLOB *input,
 435                                       DATA_BLOB *reply,
 436                                       struct tsocket_address *peer_addr,
 437                                       struct tsocket_address *my_addr,
 438                                       int datagram_reply)
 439 {
 440         bool ret;
 441         const uint16_t header_len = 6;
 442         uint16_t len;
 443         uint16_t ap_req_len;
 444         uint16_t krb_priv_len;
 445         uint16_t version;
 446         NTSTATUS nt_status;
 447         DATA_BLOB ap_req, krb_priv_req;
 448         DATA_BLOB krb_priv_rep = data_blob(NULL, 0);
 449         DATA_BLOB ap_rep = data_blob(NULL, 0);
 450         DATA_BLOB kpasswd_req, kpasswd_rep;
 451         struct cli_credentials *server_credentials;
 452         struct gensec_security *gensec_security;
 453         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 454
 455         char *keytab_name;
 456
 457         if (!tmp_ctx) {
 458                 return KDC_PROCESS_FAILED;
 459         }
 460
 461         if (kdc->am_rodc) {
 462                 talloc_free(tmp_ctx);
 463                 return KDC_PROCESS_PROXY;
 464         }
 465
 466         /* Be parinoid.  We need to ensure we don't just let the
 467          * caller lead us into a buffer overflow */
 468         if (input->length <= header_len) {
 469                 talloc_free(tmp_ctx);
 470                 return KDC_PROCESS_FAILED;
 471         }
 472
 473         len = RSVAL(input->data, 0);
 474         if (input->length != len) {
 475                 talloc_free(tmp_ctx);
 476                 return KDC_PROCESS_FAILED;
 477         }
 478
 479         /* There are two different versions of this protocol so far,
 480          * plus others in the standards pipe.  Fortunetly they all
 481          * take a very similar framing */
 482         version = RSVAL(input->data, 2);
 483         ap_req_len = RSVAL(input->data, 4);
 484         if ((ap_req_len >= len) || (ap_req_len + header_len) >= len) {
 485                 talloc_free(tmp_ctx);
 486                 return KDC_PROCESS_FAILED;
 487         }
 488
 489         krb_priv_len = len - ap_req_len;
 490         ap_req = data_blob_const(&input->data[header_len], ap_req_len);
 491         krb_priv_req = data_blob_const(&input->data[header_len + ap_req_len], krb_priv_len);
 492
 493         server_credentials = cli_credentials_init(tmp_ctx);
 494         if (!server_credentials) {
 495                 DEBUG(1, ("Failed to init server credentials\n"));
 496                 talloc_free(tmp_ctx);
 497                 return KDC_PROCESS_FAILED;
 498         }
 499
 500         /* We want the credentials subsystem to use the krb5 context
 501          * we already have, rather than a new context */
 502         cli_credentials_set_krb5_context(server_credentials, kdc->smb_krb5_context);
 503         cli_credentials_set_conf(server_credentials, kdc->task->lp_ctx);
 504
 505         keytab_name = talloc_asprintf(server_credentials, "HDB:samba4&%p", kdc->base_ctx);
 506
 507         cli_credentials_set_username(server_credentials, "kadmin/changepw", CRED_SPECIFIED);
 508         ret = cli_credentials_set_keytab_name(server_credentials, kdc->task->lp_ctx, keytab_name, CRED_SPECIFIED);
 509         if (ret != 0) {
 510                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 511                                                        KRB5_KPASSWD_HARDERROR,
 512                                                        talloc_asprintf(mem_ctx,
 513                                                                        "Failed to obtain server credentials for kadmin/changepw!"),
 514                                                        &krb_priv_rep);
 515                 ap_rep.length = 0;
 516                 if (ret) {
 517                         goto reply;
 518                 }
 519                 talloc_free(tmp_ctx);
 520                 return ret;
 521         }
 522
 523         /* We don't strictly need to call this wrapper, and could call
 524          * gensec_server_start directly, as we have no need for NTLM
 525          * and we have a PAC, but this ensures that the wrapper can be
 526          * safely extended for other helpful things in future */
 527         nt_status = samba_server_gensec_start(tmp_ctx, kdc->task->event_ctx,
 528                                               kdc->task->msg_ctx,
 529                                               kdc->task->lp_ctx,
 530                                               server_credentials,
 531                                               "kpasswd",
 532                                               &gensec_security);
 533         if (!NT_STATUS_IS_OK(nt_status)) {
 534                 talloc_free(tmp_ctx);
 535                 return KDC_PROCESS_FAILED;
 536         }
 537
 538         /* The kerberos PRIV packets include these addresses.  MIT
 539          * clients check that they are present */
 540 #if 0
 541         /* Skip this part for now, it breaks with a NetAPP filer and
 542          * in any case where the client address is behind NAT.  If
 543          * older MIT clients need this, we might have to insert more
 544          * complex code */
 545
 546         nt_status = gensec_set_local_address(gensec_security, peer_addr);
 547         if (!NT_STATUS_IS_OK(nt_status)) {
 548                 talloc_free(tmp_ctx);
 549                 return KDC_PROCESS_FAILED;
 550         }
 551 #endif
 552
 553         nt_status = gensec_set_local_address(gensec_security, my_addr);
 554         if (!NT_STATUS_IS_OK(nt_status)) {
 555                 talloc_free(tmp_ctx);
 556                 return KDC_PROCESS_FAILED;
 557         }
 558
 559         /* We want the GENSEC wrap calls to generate PRIV tokens */
 560         gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
 561
 562         nt_status = gensec_start_mech_by_name(gensec_security, "krb5");
 563         if (!NT_STATUS_IS_OK(nt_status)) {
 564                 talloc_free(tmp_ctx);
 565                 return KDC_PROCESS_FAILED;
 566         }
 567
 568         /* Accept the AP-REQ and generate teh AP-REP we need for the reply */
 569         nt_status = gensec_update(gensec_security, tmp_ctx, ap_req, &ap_rep);
 570         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 571
 572                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 573                                                        KRB5_KPASSWD_HARDERROR,
 574                                                        talloc_asprintf(mem_ctx,
 575                                                                        "gensec_update failed: %s",
 576                                                                        nt_errstr(nt_status)),
 577                                                        &krb_priv_rep);
 578                 ap_rep.length = 0;
 579                 if (ret) {
 580                         goto reply;
 581                 }
 582                 talloc_free(tmp_ctx);
 583                 return KDC_PROCESS_FAILED;
 584         }
 585
 586         /* Extract the data from the KRB-PRIV half of the message */
 587         nt_status = gensec_unwrap(gensec_security, tmp_ctx, &krb_priv_req, &kpasswd_req);
 588         if (!NT_STATUS_IS_OK(nt_status)) {
 589                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 590                                                        KRB5_KPASSWD_HARDERROR,
 591                                                        talloc_asprintf(mem_ctx,
 592                                                                        "gensec_unwrap failed: %s",
 593                                                                        nt_errstr(nt_status)),
 594                                                        &krb_priv_rep);
 595                 ap_rep.length = 0;
 596                 if (ret) {
 597                         goto reply;
 598                 }
 599                 talloc_free(tmp_ctx);
 600                 return KDC_PROCESS_FAILED;
 601         }
 602
 603         /* Figure out something to do with it (probably changing a password...) */
 604         ret = kpasswd_process_request(kdc, tmp_ctx,
 605                                       gensec_security,
 606                                       version,
 607                                       &kpasswd_req, &kpasswd_rep);
 608         if (!ret) {
 609                 /* Argh! */
 610                 talloc_free(tmp_ctx);
 611                 return KDC_PROCESS_FAILED;
 612         }
 613
 614         /* And wrap up the reply: This ensures that the error message
 615          * or success can be verified by the client */
 616         nt_status = gensec_wrap(gensec_security, tmp_ctx,
 617                                 &kpasswd_rep, &krb_priv_rep);
 618         if (!NT_STATUS_IS_OK(nt_status)) {
 619                 ret = kpasswdd_make_unauth_error_reply(kdc, mem_ctx,
 620                                                        KRB5_KPASSWD_HARDERROR,
 621                                                        talloc_asprintf(mem_ctx,
 622                                                                        "gensec_wrap failed: %s",
 623                                                                        nt_errstr(nt_status)),
 624                                                        &krb_priv_rep);
 625                 ap_rep.length = 0;
 626                 if (ret) {
 627                         goto reply;
 628                 }
 629                 talloc_free(tmp_ctx);
 630                 return KDC_PROCESS_FAILED;
 631         }
 632
 633 reply:
 634         *reply = data_blob_talloc(mem_ctx, NULL, krb_priv_rep.length + ap_rep.length + header_len);
 635         if (!reply->data) {
 636                 talloc_free(tmp_ctx);
 637                 return KDC_PROCESS_FAILED;
 638         }
 639
 640         RSSVAL(reply->data, 0, reply->length);
 641         RSSVAL(reply->data, 2, 1); /* This is a version 1 reply, MS change/set or otherwise */
 642         RSSVAL(reply->data, 4, ap_rep.length);
 643         memcpy(reply->data + header_len,
 644                ap_rep.data,
 645                ap_rep.length);
 646         memcpy(reply->data + header_len + ap_rep.length,
 647                krb_priv_rep.data,
 648                krb_priv_rep.length);
 649
 650         talloc_free(tmp_ctx);
 651         return KDC_PROCESS_OK;
 652 }
 653