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