source4/libcli/ldap/ldap_bind.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    LDAP bind calls
   5
   6    Copyright (C) Andrew Tridgell  2005
   7    Copyright (C) Volker Lendecke  2004
   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
  24 #include "includes.h"
  25 #include "libcli/ldap/libcli_ldap.h"
  26 #include "libcli/ldap/ldap_proto.h"
  27 #include "libcli/ldap/ldap_client.h"
  28 #include "lib/tls/tls.h"
  29 #include "auth/gensec/gensec.h"
  30 #include "auth/gensec/gensec_internal.h" /* TODO: remove this */
  31 #include "source4/auth/gensec/gensec_tstream.h"
  32 #include "auth/credentials/credentials.h"
  33 #include "lib/stream/packet.h"
  34 #include "param/param.h"
  35 #include "param/loadparm.h"
  36 #include "librpc/gen_ndr/ads.h"
  37
  38 struct ldap_simple_creds {
  39         const char *dn;
  40         const char *pw;
  41 };
  42
  43 _PUBLIC_ NTSTATUS ldap_rebind(struct ldap_connection *conn)
  44 {
  45         NTSTATUS status;
  46         struct ldap_simple_creds *creds;
  47
  48         switch (conn->bind.type) {
  49         case LDAP_BIND_SASL:
  50                 status = ldap_bind_sasl(conn, (struct cli_credentials *)conn->bind.creds,
  51                                         conn->lp_ctx);
  52                 break;
  53
  54         case LDAP_BIND_SIMPLE:
  55                 creds = (struct ldap_simple_creds *)conn->bind.creds;
  56
  57                 if (creds == NULL) {
  58                         return NT_STATUS_UNSUCCESSFUL;
  59                 }
  60
  61                 status = ldap_bind_simple(conn, creds->dn, creds->pw);
  62                 break;
  63
  64         default:
  65                 return NT_STATUS_UNSUCCESSFUL;
  66         }
  67
  68         return status;
  69 }
  70
  71
  72 static struct ldap_message *new_ldap_simple_bind_msg(struct ldap_connection *conn,
  73                                                      const char *dn, const char *pw)
  74 {
  75         struct ldap_message *res;
  76
  77         res = new_ldap_message(conn);
  78         if (!res) {
  79                 return NULL;
  80         }
  81
  82         res->type = LDAP_TAG_BindRequest;
  83         res->r.BindRequest.version = 3;
  84         res->r.BindRequest.dn = talloc_strdup(res, dn);
  85         res->r.BindRequest.mechanism = LDAP_AUTH_MECH_SIMPLE;
  86         res->r.BindRequest.creds.password = talloc_strdup(res, pw);
  87         res->controls = NULL;
  88
  89         return res;
  90 }
  91
  92
  93 /*
  94   perform a simple username/password bind
  95 */
  96 _PUBLIC_ NTSTATUS ldap_bind_simple(struct ldap_connection *conn,
  97                           const char *userdn, const char *password)
  98 {
  99         struct ldap_request *req;
 100         struct ldap_message *msg;
 101         const char *dn, *pw;
 102         NTSTATUS status;
 103
 104         if (conn == NULL) {
 105                 return NT_STATUS_INVALID_CONNECTION;
 106         }
 107
 108         if (userdn) {
 109                 dn = userdn;
 110         } else {
 111                 if (conn->auth_dn) {
 112                         dn = conn->auth_dn;
 113                 } else {
 114                         dn = "";
 115                 }
 116         }
 117
 118         if (password) {
 119                 pw = password;
 120         } else {
 121                 if (conn->simple_pw) {
 122                         pw = conn->simple_pw;
 123                 } else {
 124                         pw = "";
 125                 }
 126         }
 127
 128         msg = new_ldap_simple_bind_msg(conn, dn, pw);
 129         NT_STATUS_HAVE_NO_MEMORY(msg);
 130
 131         /* send the request */
 132         req = ldap_request_send(conn, msg);
 133         talloc_free(msg);
 134         NT_STATUS_HAVE_NO_MEMORY(req);
 135
 136         /* wait for replies */
 137         status = ldap_request_wait(req);
 138         if (!NT_STATUS_IS_OK(status)) {
 139                 talloc_free(req);
 140                 return status;
 141         }
 142
 143         /* check its a valid reply */
 144         msg = req->replies[0];
 145         if (msg->type != LDAP_TAG_BindResponse) {
 146                 talloc_free(req);
 147                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 148         }
 149
 150         status = ldap_check_response(conn, &msg->r.BindResponse.response);
 151
 152         talloc_free(req);
 153
 154         if (NT_STATUS_IS_OK(status)) {
 155                 struct ldap_simple_creds *creds = talloc(conn, struct ldap_simple_creds);
 156                 if (creds == NULL) {
 157                         return NT_STATUS_NO_MEMORY;
 158                 }
 159                 creds->dn = talloc_strdup(creds, dn);
 160                 creds->pw = talloc_strdup(creds, pw);
 161                 if (creds->dn == NULL || creds->pw == NULL) {
 162                         return NT_STATUS_NO_MEMORY;
 163                 }
 164                 conn->bind.type = LDAP_BIND_SIMPLE;
 165                 conn->bind.creds = creds;
 166         }
 167
 168         return status;
 169 }
 170
 171
 172 static struct ldap_message *new_ldap_sasl_bind_msg(struct ldap_connection *conn,
 173                                                    const char *sasl_mechanism,
 174                                                    DATA_BLOB *secblob)
 175 {
 176         struct ldap_message *res;
 177
 178         res = new_ldap_message(conn);
 179         if (!res) {
 180                 return NULL;
 181         }
 182
 183         res->type = LDAP_TAG_BindRequest;
 184         res->r.BindRequest.version = 3;
 185         res->r.BindRequest.dn = "";
 186         res->r.BindRequest.mechanism = LDAP_AUTH_MECH_SASL;
 187         res->r.BindRequest.creds.SASL.mechanism = talloc_strdup(res, sasl_mechanism);
 188         if (secblob) {
 189                 res->r.BindRequest.creds.SASL.secblob = talloc(res, DATA_BLOB);
 190                 if (!res->r.BindRequest.creds.SASL.secblob) {
 191                         talloc_free(res);
 192                         return NULL;
 193                 }
 194                 *res->r.BindRequest.creds.SASL.secblob = *secblob;
 195         } else {
 196                 res->r.BindRequest.creds.SASL.secblob = NULL;
 197         }
 198         res->controls = NULL;
 199
 200         return res;
 201 }
 202
 203
 204 /*
 205   perform a sasl bind using the given credentials
 206 */
 207 _PUBLIC_ NTSTATUS ldap_bind_sasl(struct ldap_connection *conn,
 208                         struct cli_credentials *creds,
 209                         struct loadparm_context *lp_ctx)
 210 {
 211         NTSTATUS status;
 212         TALLOC_CTX *tmp_ctx = NULL;
 213
 214         DATA_BLOB input = data_blob(NULL, 0);
 215         DATA_BLOB output = data_blob(NULL, 0);
 216
 217         struct ldap_message **sasl_mechs_msgs;
 218         struct ldap_SearchResEntry *search;
 219         int count, i;
 220         bool first = true;
 221         int wrap_flags = 0;
 222         const char **sasl_names;
 223         uint32_t old_gensec_features;
 224         static const char *supported_sasl_mech_attrs[] = {
 225                 "supportedSASLMechanisms",
 226                 NULL
 227         };
 228         unsigned int logon_retries = 0;
 229         size_t queue_length;
 230
 231         if (conn->sockets.active == NULL) {
 232                 status = NT_STATUS_CONNECTION_DISCONNECTED;
 233                 goto failed;
 234         }
 235
 236         queue_length = tevent_queue_length(conn->sockets.send_queue);
 237         if (queue_length != 0) {
 238                 status = NT_STATUS_INVALID_PARAMETER_MIX;
 239                 DEBUG(1, ("SASL bind triggered with non empty send_queue[%zu]: %s\n",
 240                           queue_length, nt_errstr(status)));
 241                 goto failed;
 242         }
 243
 244         if (conn->pending != NULL) {
 245                 status = NT_STATUS_INVALID_PARAMETER_MIX;
 246                 DEBUG(1, ("SASL bind triggered with pending requests: %s\n",
 247                           nt_errstr(status)));
 248                 goto failed;
 249         }
 250
 251         status = ildap_search(conn, "", LDAP_SEARCH_SCOPE_BASE, "", supported_sasl_mech_attrs,
 252                               false, NULL, NULL, &sasl_mechs_msgs);
 253         if (!NT_STATUS_IS_OK(status)) {
 254                 DEBUG(1, ("Failed to inquire of target's available sasl mechs in rootdse search: %s\n",
 255                           nt_errstr(status)));
 256                 goto failed;
 257         }
 258
 259         count = ildap_count_entries(conn, sasl_mechs_msgs);
 260         if (count != 1) {
 261                 DEBUG(1, ("Failed to inquire of target's available sasl mechs in rootdse search: wrong number of replies: %d\n",
 262                           count));
 263                 goto failed;
 264         }
 265
 266         tmp_ctx = talloc_new(conn);
 267         if (tmp_ctx == NULL) {
 268                 status = NT_STATUS_NO_MEMORY;
 269                 goto failed;
 270         }
 271
 272         search = &sasl_mechs_msgs[0]->r.SearchResultEntry;
 273         if (search->num_attributes != 1) {
 274                 DEBUG(1, ("Failed to inquire of target's available sasl mechs in rootdse search: wrong number of attributes: %d != 1\n",
 275                           search->num_attributes));
 276                 goto failed;
 277         }
 278
 279         sasl_names = talloc_array(tmp_ctx, const char *, search->attributes[0].num_values + 1);
 280         if (!sasl_names) {
 281                 DEBUG(1, ("talloc_arry(char *, %d) failed\n",
 282                           count));
 283                 goto failed;
 284         }
 285
 286         for (i=0; i<search->attributes[0].num_values; i++) {
 287                 sasl_names[i] = (const char *)search->attributes[0].values[i].data;
 288         }
 289         sasl_names[i] = NULL;
 290
 291         gensec_init();
 292
 293         if (conn->sockets.active == conn->sockets.tls) {
 294                 /*
 295                  * require Kerberos SIGN/SEAL only if we don't use SSL
 296                  * Windows seem not to like double encryption
 297                  */
 298                 wrap_flags = 0;
 299         } else if (cli_credentials_is_anonymous(creds)) {
 300                 /*
 301                  * anonymous isn't protected
 302                  */
 303                 wrap_flags = 0;
 304         } else {
 305                 wrap_flags = lpcfg_client_ldap_sasl_wrapping(lp_ctx);
 306         }
 307
 308 try_logon_again:
 309         /*
 310           we loop back here on a logon failure, and re-create the
 311           gensec session. The logon_retries counter ensures we don't
 312           loop forever.
 313          */
 314         data_blob_free(&input);
 315         TALLOC_FREE(conn->gensec);
 316
 317         status = gensec_client_start(conn, &conn->gensec,
 318                                      lpcfg_gensec_settings(conn, lp_ctx));
 319         if (!NT_STATUS_IS_OK(status)) {
 320                 DEBUG(0, ("Failed to start GENSEC engine (%s)\n", nt_errstr(status)));
 321                 goto failed;
 322         }
 323
 324         old_gensec_features = cli_credentials_get_gensec_features(creds);
 325         if (wrap_flags == 0) {
 326                 cli_credentials_set_gensec_features(creds,
 327                                 old_gensec_features & ~(GENSEC_FEATURE_SIGN|GENSEC_FEATURE_SEAL),
 328                                 CRED_SPECIFIED);
 329         }
 330
 331         /* this call also sets the gensec_want_features */
 332         status = gensec_set_credentials(conn->gensec, creds);
 333         if (!NT_STATUS_IS_OK(status)) {
 334                 DEBUG(1, ("Failed to set GENSEC creds: %s\n",
 335                           nt_errstr(status)));
 336                 goto failed;
 337         }
 338
 339         /* reset the original gensec_features (on the credentials
 340          * context, so we don't tattoo it ) */
 341         cli_credentials_set_gensec_features(creds,
 342                                             old_gensec_features,
 343                                             CRED_SPECIFIED);
 344
 345         if (wrap_flags & ADS_AUTH_SASL_SEAL) {
 346                 gensec_want_feature(conn->gensec, GENSEC_FEATURE_SIGN);
 347                 gensec_want_feature(conn->gensec, GENSEC_FEATURE_SEAL);
 348         }
 349         if (wrap_flags & ADS_AUTH_SASL_SIGN) {
 350                 gensec_want_feature(conn->gensec, GENSEC_FEATURE_SIGN);
 351         }
 352
 353         /*
 354          * This is an indication for the NTLMSSP backend to
 355          * also encrypt when only GENSEC_FEATURE_SIGN is requested
 356          * in gensec_[un]wrap().
 357          */
 358         gensec_want_feature(conn->gensec, GENSEC_FEATURE_LDAP_STYLE);
 359
 360         if (conn->host) {
 361                 status = gensec_set_target_hostname(conn->gensec, conn->host);
 362                 if (!NT_STATUS_IS_OK(status)) {
 363                         DEBUG(1, ("Failed to set GENSEC target hostname: %s\n",
 364                                   nt_errstr(status)));
 365                         goto failed;
 366                 }
 367         }
 368
 369         status = gensec_set_target_service(conn->gensec, "ldap");
 370         if (!NT_STATUS_IS_OK(status)) {
 371                 DEBUG(1, ("Failed to set GENSEC target service: %s\n",
 372                           nt_errstr(status)));
 373                 goto failed;
 374         }
 375
 376         status = gensec_start_mech_by_sasl_list(conn->gensec, sasl_names);
 377         if (!NT_STATUS_IS_OK(status)) {
 378                 DEBUG(1, ("None of the %d proposed SASL mechs were acceptable: %s\n",
 379                           count, nt_errstr(status)));
 380                 goto failed;
 381         }
 382
 383         while (1) {
 384                 NTSTATUS gensec_status;
 385                 struct ldap_message *response;
 386                 struct ldap_message *msg;
 387                 struct ldap_request *req;
 388                 int result = LDAP_OTHER;
 389
 390                 status = gensec_update(conn->gensec, tmp_ctx,
 391                                        input,
 392                                        &output);
 393                 /* The status value here, from GENSEC is vital to the security
 394                  * of the system.  Even if the other end accepts, if GENSEC
 395                  * claims 'MORE_PROCESSING_REQUIRED' then you must keep
 396                  * feeding it blobs, or else the remote host/attacker might
 397                  * avoid mutual authentication requirements.
 398                  *
 399                  * Likewise, you must not feed GENSEC too much (after the OK),
 400                  * it doesn't like that either.
 401                  *
 402                  * For SASL/EXTERNAL, there is no data to send, but we still
 403                  * must send the actual Bind request the first time around.
 404                  * Otherwise, a result of NT_STATUS_OK with 0 output means the
 405                  * end of a multi-step authentication, and no message must be
 406                  * sent.
 407                  */
 408
 409                 gensec_status = status;
 410
 411                 if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED) &&
 412                     !NT_STATUS_IS_OK(status)) {
 413                         break;
 414                 }
 415                 if (NT_STATUS_IS_OK(status) && output.length == 0) {
 416                         if (!first)
 417                                 break;
 418                 }
 419                 first = false;
 420
 421                 /* Perhaps we should make gensec_start_mech_by_sasl_list() return the name we got? */
 422                 msg = new_ldap_sasl_bind_msg(tmp_ctx, conn->gensec->ops->sasl_name, (output.data?&output:NULL));
 423                 if (msg == NULL) {
 424                         status = NT_STATUS_NO_MEMORY;
 425                         goto failed;
 426                 }
 427
 428                 req = ldap_request_send(conn, msg);
 429                 if (req == NULL) {
 430                         status = NT_STATUS_NO_MEMORY;
 431                         goto failed;
 432                 }
 433                 talloc_reparent(conn, tmp_ctx, req);
 434
 435                 status = ldap_result_n(req, 0, &response);
 436                 if (!NT_STATUS_IS_OK(status)) {
 437                         goto failed;
 438                 }
 439
 440                 if (response->type != LDAP_TAG_BindResponse) {
 441                         status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 442                         goto failed;
 443                 }
 444
 445                 result = response->r.BindResponse.response.resultcode;
 446
 447                 if (result == LDAP_STRONG_AUTH_REQUIRED) {
 448                         if (wrap_flags == 0) {
 449                                 wrap_flags = ADS_AUTH_SASL_SIGN;
 450                                 goto try_logon_again;
 451                         }
 452                 }
 453
 454                 if (result == LDAP_INVALID_CREDENTIALS) {
 455                         /*
 456                           try a second time on invalid credentials, to
 457                           give the user a chance to re-enter the
 458                           password and to handle the case where our
 459                           kerberos ticket is invalid as the server
 460                           password has changed
 461                         */
 462                         const char *principal;
 463
 464                         principal = gensec_get_target_principal(conn->gensec);
 465                         if (principal == NULL) {
 466                                 const char *hostname = gensec_get_target_hostname(conn->gensec);
 467                                 const char *service  = gensec_get_target_service(conn->gensec);
 468                                 if (hostname != NULL && service != NULL) {
 469                                         principal = talloc_asprintf(tmp_ctx, "%s/%s", service, hostname);
 470                                 }
 471                         }
 472
 473                         if (cli_credentials_failed_kerberos_login(creds, principal, &logon_retries) ||
 474                             cli_credentials_wrong_password(creds)) {
 475                                 /*
 476                                   destroy our gensec session and loop
 477                                   back up to the top to retry,
 478                                   offering the user a chance to enter
 479                                   new credentials, or get a new ticket
 480                                   if using kerberos
 481                                  */
 482                                 goto try_logon_again;
 483                         }
 484                 }
 485
 486                 if (result != LDAP_SUCCESS && result != LDAP_SASL_BIND_IN_PROGRESS) {
 487                         status = ldap_check_response(conn,
 488                                                      &response->r.BindResponse.response);
 489                         break;
 490                 }
 491
 492                 /* This is where we check if GENSEC wanted to be fed more data */
 493                 if (!NT_STATUS_EQUAL(gensec_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 494                         break;
 495                 }
 496                 if (response->r.BindResponse.SASL.secblob) {
 497                         input = *response->r.BindResponse.SASL.secblob;
 498                 } else {
 499                         input = data_blob(NULL, 0);
 500                 }
 501         }
 502
 503         TALLOC_FREE(tmp_ctx);
 504
 505         if (!NT_STATUS_IS_OK(status)) {
 506                 goto failed;
 507         }
 508
 509         conn->bind.type = LDAP_BIND_SASL;
 510         conn->bind.creds = creds;
 511
 512         if (wrap_flags & ADS_AUTH_SASL_SEAL) {
 513                 if (!gensec_have_feature(conn->gensec, GENSEC_FEATURE_SIGN)) {
 514                         return NT_STATUS_INVALID_NETWORK_RESPONSE;
 515                 }
 516
 517                 if (!gensec_have_feature(conn->gensec, GENSEC_FEATURE_SEAL)) {
 518                         return NT_STATUS_INVALID_NETWORK_RESPONSE;
 519                 }
 520         } else if (wrap_flags & ADS_AUTH_SASL_SIGN) {
 521                 if (!gensec_have_feature(conn->gensec, GENSEC_FEATURE_SIGN)) {
 522                         return NT_STATUS_INVALID_NETWORK_RESPONSE;
 523                 }
 524         }
 525
 526         if (!gensec_have_feature(conn->gensec, GENSEC_FEATURE_SIGN) &&
 527             !gensec_have_feature(conn->gensec, GENSEC_FEATURE_SEAL)) {
 528                 return NT_STATUS_OK;
 529         }
 530
 531         status = gensec_create_tstream(conn->sockets.raw,
 532                                        conn->gensec,
 533                                        conn->sockets.raw,
 534                                        &conn->sockets.sasl);
 535         if (!NT_STATUS_IS_OK(status)) {
 536                 goto failed;
 537         }
 538
 539         conn->sockets.active = conn->sockets.sasl;
 540
 541         return NT_STATUS_OK;
 542
 543 failed:
 544         talloc_free(tmp_ctx);
 545         talloc_free(conn->gensec);
 546         conn->gensec = NULL;
 547         return status;
 548 }