source4/libcli/ldap/ldap_bind.c

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