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_socket.h"
  31 #include "auth/credentials/credentials.h"
  32 #include "lib/stream/packet.h"
  33 #include "param/param.h"
  34
  35 struct ldap_simple_creds {
  36         const char *dn;
  37         const char *pw;
  38 };
  39
  40 _PUBLIC_ NTSTATUS ldap_rebind(struct ldap_connection *conn)
  41 {
  42         NTSTATUS status;
  43         struct ldap_simple_creds *creds;
  44
  45         switch (conn->bind.type) {
  46         case LDAP_BIND_SASL:
  47                 status = ldap_bind_sasl(conn, (struct cli_credentials *)conn->bind.creds,
  48                                         conn->lp_ctx);
  49                 break;
  50
  51         case LDAP_BIND_SIMPLE:
  52                 creds = (struct ldap_simple_creds *)conn->bind.creds;
  53
  54                 if (creds == NULL) {
  55                         return NT_STATUS_UNSUCCESSFUL;
  56                 }
  57
  58                 status = ldap_bind_simple(conn, creds->dn, creds->pw);
  59                 break;
  60
  61         default:
  62                 return NT_STATUS_UNSUCCESSFUL;
  63         }
  64
  65         return status;
  66 }
  67
  68
  69 static struct ldap_message *new_ldap_simple_bind_msg(struct ldap_connection *conn,
  70                                                      const char *dn, const char *pw)
  71 {
  72         struct ldap_message *res;
  73
  74         res = new_ldap_message(conn);
  75         if (!res) {
  76                 return NULL;
  77         }
  78
  79         res->type = LDAP_TAG_BindRequest;
  80         res->r.BindRequest.version = 3;
  81         res->r.BindRequest.dn = talloc_strdup(res, dn);
  82         res->r.BindRequest.mechanism = LDAP_AUTH_MECH_SIMPLE;
  83         res->r.BindRequest.creds.password = talloc_strdup(res, pw);
  84         res->controls = NULL;
  85
  86         return res;
  87 }
  88
  89
  90 /*
  91   perform a simple username/password bind
  92 */
  93 _PUBLIC_ NTSTATUS ldap_bind_simple(struct ldap_connection *conn,
  94                           const char *userdn, const char *password)
  95 {
  96         struct ldap_request *req;
  97         struct ldap_message *msg;
  98         const char *dn, *pw;
  99         NTSTATUS status;
 100
 101         if (conn == NULL) {
 102                 return NT_STATUS_INVALID_CONNECTION;
 103         }
 104
 105         if (userdn) {
 106                 dn = userdn;
 107         } else {
 108                 if (conn->auth_dn) {
 109                         dn = conn->auth_dn;
 110                 } else {
 111                         dn = "";
 112                 }
 113         }
 114
 115         if (password) {
 116                 pw = password;
 117         } else {
 118                 if (conn->simple_pw) {
 119                         pw = conn->simple_pw;
 120                 } else {
 121                         pw = "";
 122                 }
 123         }
 124
 125         msg = new_ldap_simple_bind_msg(conn, dn, pw);
 126         NT_STATUS_HAVE_NO_MEMORY(msg);
 127
 128         /* send the request */
 129         req = ldap_request_send(conn, msg);
 130         talloc_free(msg);
 131         NT_STATUS_HAVE_NO_MEMORY(req);
 132
 133         /* wait for replies */
 134         status = ldap_request_wait(req);
 135         if (!NT_STATUS_IS_OK(status)) {
 136                 talloc_free(req);
 137                 return status;
 138         }
 139
 140         /* check its a valid reply */
 141         msg = req->replies[0];
 142         if (msg->type != LDAP_TAG_BindResponse) {
 143                 talloc_free(req);
 144                 return NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 145         }
 146
 147         status = ldap_check_response(conn, &msg->r.BindResponse.response);
 148
 149         talloc_free(req);
 150
 151         if (NT_STATUS_IS_OK(status)) {
 152                 struct ldap_simple_creds *creds = talloc(conn, struct ldap_simple_creds);
 153                 if (creds == NULL) {
 154                         return NT_STATUS_NO_MEMORY;
 155                 }
 156                 creds->dn = talloc_strdup(creds, dn);
 157                 creds->pw = talloc_strdup(creds, pw);
 158                 if (creds->dn == NULL || creds->pw == NULL) {
 159                         return NT_STATUS_NO_MEMORY;
 160                 }
 161                 conn->bind.type = LDAP_BIND_SIMPLE;
 162                 conn->bind.creds = creds;
 163         }
 164
 165         return status;
 166 }
 167
 168
 169 static struct ldap_message *new_ldap_sasl_bind_msg(struct ldap_connection *conn,
 170                                                    const char *sasl_mechanism,
 171                                                    DATA_BLOB *secblob)
 172 {
 173         struct ldap_message *res;
 174
 175         res = new_ldap_message(conn);
 176         if (!res) {
 177                 return NULL;
 178         }
 179
 180         res->type = LDAP_TAG_BindRequest;
 181         res->r.BindRequest.version = 3;
 182         res->r.BindRequest.dn = "";
 183         res->r.BindRequest.mechanism = LDAP_AUTH_MECH_SASL;
 184         res->r.BindRequest.creds.SASL.mechanism = talloc_strdup(res, sasl_mechanism);
 185         if (secblob) {
 186                 res->r.BindRequest.creds.SASL.secblob = talloc(res, DATA_BLOB);
 187                 if (!res->r.BindRequest.creds.SASL.secblob) {
 188                         talloc_free(res);
 189                         return NULL;
 190                 }
 191                 *res->r.BindRequest.creds.SASL.secblob = *secblob;
 192         } else {
 193                 res->r.BindRequest.creds.SASL.secblob = NULL;
 194         }
 195         res->controls = NULL;
 196
 197         return res;
 198 }
 199
 200
 201 /*
 202   perform a sasl bind using the given credentials
 203 */
 204 _PUBLIC_ NTSTATUS ldap_bind_sasl(struct ldap_connection *conn,
 205                         struct cli_credentials *creds,
 206                         struct loadparm_context *lp_ctx)
 207 {
 208         NTSTATUS status;
 209         TALLOC_CTX *tmp_ctx = NULL;
 210
 211         DATA_BLOB input = data_blob(NULL, 0);
 212         DATA_BLOB output = data_blob(NULL, 0);
 213
 214         struct ldap_message **sasl_mechs_msgs;
 215         struct ldap_SearchResEntry *search;
 216         int count, i;
 217
 218         const char **sasl_names;
 219         uint32_t old_gensec_features;
 220         static const char *supported_sasl_mech_attrs[] = {
 221                 "supportedSASLMechanisms",
 222                 NULL
 223         };
 224         unsigned int logon_retries = 0;
 225
 226         status = ildap_search(conn, "", LDAP_SEARCH_SCOPE_BASE, "", supported_sasl_mech_attrs,
 227                               false, NULL, NULL, &sasl_mechs_msgs);
 228         if (!NT_STATUS_IS_OK(status)) {
 229                 DEBUG(1, ("Failed to inquire of target's available sasl mechs in rootdse search: %s\n",
 230                           nt_errstr(status)));
 231                 goto failed;
 232         }
 233
 234         count = ildap_count_entries(conn, sasl_mechs_msgs);
 235         if (count != 1) {
 236                 DEBUG(1, ("Failed to inquire of target's available sasl mechs in rootdse search: wrong number of replies: %d\n",
 237                           count));
 238                 goto failed;
 239         }
 240
 241         tmp_ctx = talloc_new(conn);
 242         if (tmp_ctx == NULL) goto failed;
 243
 244         search = &sasl_mechs_msgs[0]->r.SearchResultEntry;
 245         if (search->num_attributes != 1) {
 246                 DEBUG(1, ("Failed to inquire of target's available sasl mechs in rootdse search: wrong number of attributes: %d != 1\n",
 247                           search->num_attributes));
 248                 goto failed;
 249         }
 250
 251         sasl_names = talloc_array(tmp_ctx, const char *, search->attributes[0].num_values + 1);
 252         if (!sasl_names) {
 253                 DEBUG(1, ("talloc_arry(char *, %d) failed\n",
 254                           count));
 255                 goto failed;
 256         }
 257
 258         for (i=0; i<search->attributes[0].num_values; i++) {
 259                 sasl_names[i] = (const char *)search->attributes[0].values[i].data;
 260         }
 261         sasl_names[i] = NULL;
 262
 263         gensec_init();
 264
 265 try_logon_again:
 266         /*
 267           we loop back here on a logon failure, and re-create the
 268           gensec session. The logon_retries counter ensures we don't
 269           loop forever.
 270          */
 271
 272         status = gensec_client_start(conn, &conn->gensec,
 273                                      lpcfg_gensec_settings(conn, lp_ctx));
 274         if (!NT_STATUS_IS_OK(status)) {
 275                 DEBUG(0, ("Failed to start GENSEC engine (%s)\n", nt_errstr(status)));
 276                 goto failed;
 277         }
 278
 279         /* require Kerberos SIGN/SEAL only if we don't use SSL
 280          * Windows seem not to like double encryption */
 281         old_gensec_features = cli_credentials_get_gensec_features(creds);
 282         if (tls_enabled(conn->sock)) {
 283                 cli_credentials_set_gensec_features(creds, old_gensec_features & ~(GENSEC_FEATURE_SIGN|GENSEC_FEATURE_SEAL));
 284         }
 285
 286         /* this call also sets the gensec_want_features */
 287         status = gensec_set_credentials(conn->gensec, creds);
 288         if (!NT_STATUS_IS_OK(status)) {
 289                 DEBUG(1, ("Failed to set GENSEC creds: %s\n",
 290                           nt_errstr(status)));
 291                 goto failed;
 292         }
 293
 294         /* reset the original gensec_features (on the credentials
 295          * context, so we don't tatoo it ) */
 296         cli_credentials_set_gensec_features(creds, old_gensec_features);
 297
 298         if (conn->host) {
 299                 status = gensec_set_target_hostname(conn->gensec, conn->host);
 300                 if (!NT_STATUS_IS_OK(status)) {
 301                         DEBUG(1, ("Failed to set GENSEC target hostname: %s\n",
 302                                   nt_errstr(status)));
 303                         goto failed;
 304                 }
 305         }
 306
 307         status = gensec_set_target_service(conn->gensec, "ldap");
 308         if (!NT_STATUS_IS_OK(status)) {
 309                 DEBUG(1, ("Failed to set GENSEC target service: %s\n",
 310                           nt_errstr(status)));
 311                 goto failed;
 312         }
 313
 314         status = gensec_start_mech_by_sasl_list(conn->gensec, sasl_names);
 315         if (!NT_STATUS_IS_OK(status)) {
 316                 DEBUG(1, ("None of the %d proposed SASL mechs were acceptable: %s\n",
 317                           count, nt_errstr(status)));
 318                 goto failed;
 319         }
 320
 321         while (1) {
 322                 NTSTATUS gensec_status;
 323                 struct ldap_message *response;
 324                 struct ldap_message *msg;
 325                 struct ldap_request *req;
 326                 int result = LDAP_OTHER;
 327
 328                 status = gensec_update(conn->gensec, tmp_ctx,
 329                                        conn->event.event_ctx,
 330                                        input,
 331                                        &output);
 332                 /* The status value here, from GENSEC is vital to the security
 333                  * of the system.  Even if the other end accepts, if GENSEC
 334                  * claims 'MORE_PROCESSING_REQUIRED' then you must keep
 335                  * feeding it blobs, or else the remote host/attacker might
 336                  * avoid mutal authentication requirements.
 337                  *
 338                  * Likewise, you must not feed GENSEC too much (after the OK),
 339                  * it doesn't like that either
 340                  */
 341
 342                 gensec_status = status;
 343
 344                 if (!NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED) &&
 345                     !NT_STATUS_IS_OK(status)) {
 346                         break;
 347                 }
 348                 if (NT_STATUS_IS_OK(status) && output.length == 0) {
 349                         break;
 350                 }
 351
 352                 /* Perhaps we should make gensec_start_mech_by_sasl_list() return the name we got? */
 353                 msg = new_ldap_sasl_bind_msg(tmp_ctx, conn->gensec->ops->sasl_name, (output.data?&output:NULL));
 354                 if (msg == NULL) {
 355                         status = NT_STATUS_NO_MEMORY;
 356                         goto failed;
 357                 }
 358
 359                 req = ldap_request_send(conn, msg);
 360                 if (req == NULL) {
 361                         status = NT_STATUS_NO_MEMORY;
 362                         goto failed;
 363                 }
 364                 talloc_reparent(conn, tmp_ctx, req);
 365
 366                 status = ldap_result_n(req, 0, &response);
 367                 if (!NT_STATUS_IS_OK(status)) {
 368                         goto failed;
 369                 }
 370
 371                 if (response->type != LDAP_TAG_BindResponse) {
 372                         status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 373                         goto failed;
 374                 }
 375
 376                 result = response->r.BindResponse.response.resultcode;
 377
 378                 if (result == LDAP_INVALID_CREDENTIALS) {
 379                         /*
 380                           try a second time on invalid credentials, to
 381                           give the user a chance to re-enter the
 382                           password and to handle the case where our
 383                           kerberos ticket is invalid as the server
 384                           password has changed
 385                         */
 386                         const char *principal;
 387
 388                         principal = gensec_get_target_principal(conn->gensec);
 389                         if (principal == NULL) {
 390                                 const char *hostname = gensec_get_target_hostname(conn->gensec);
 391                                 const char *service  = gensec_get_target_service(conn->gensec);
 392                                 if (hostname != NULL && service != NULL) {
 393                                         principal = talloc_asprintf(tmp_ctx, "%s/%s", service, hostname);
 394                                 }
 395                         }
 396
 397                         if (cli_credentials_failed_kerberos_login(creds, principal, &logon_retries) ||
 398                             cli_credentials_wrong_password(creds)) {
 399                                 /*
 400                                   destroy our gensec session and loop
 401                                   back up to the top to retry,
 402                                   offering the user a chance to enter
 403                                   new credentials, or get a new ticket
 404                                   if using kerberos
 405                                  */
 406                                 talloc_free(conn->gensec);
 407                                 conn->gensec = NULL;
 408                                 goto try_logon_again;
 409                         }
 410                 }
 411
 412                 if (result != LDAP_SUCCESS && result != LDAP_SASL_BIND_IN_PROGRESS) {
 413                         status = ldap_check_response(conn,
 414                                                      &response->r.BindResponse.response);
 415                         break;
 416                 }
 417
 418                 /* This is where we check if GENSEC wanted to be fed more data */
 419                 if (!NT_STATUS_EQUAL(gensec_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 420                         break;
 421                 }
 422                 if (response->r.BindResponse.SASL.secblob) {
 423                         input = *response->r.BindResponse.SASL.secblob;
 424                 } else {
 425                         input = data_blob(NULL, 0);
 426                 }
 427         }
 428
 429         talloc_free(tmp_ctx);
 430
 431         if (NT_STATUS_IS_OK(status)) {
 432                 struct socket_context *sasl_socket;
 433                 status = gensec_socket_init(conn->gensec,
 434                                             conn,
 435                                             conn->sock,
 436                                             conn->event.event_ctx,
 437                                             ldap_read_io_handler,
 438                                             conn,
 439                                             &sasl_socket);
 440                 if (!NT_STATUS_IS_OK(status)) goto failed;
 441
 442                 conn->sock = sasl_socket;
 443                 packet_set_socket(conn->packet, conn->sock);
 444
 445                 conn->bind.type = LDAP_BIND_SASL;
 446                 conn->bind.creds = creds;
 447         }
 448
 449         return status;
 450
 451 failed:
 452         talloc_free(tmp_ctx);
 453         talloc_free(conn->gensec);
 454         conn->gensec = NULL;
 455         return status;
 456 }