source3/auth/auth_samba4.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Authenticate against Samba4's auth subsystem
   4    Copyright (C) Volker Lendecke 2008
   5    Copyright (C) Andrew Bartlett 2010
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "source3/include/auth.h"
  23 #include "source3/include/messages.h"
  24 #include "source4/auth/auth.h"
  25 #include "auth/auth_sam_reply.h"
  26 #include "param/param.h"
  27 #include "source4/lib/events/events.h"
  28 #include "source4/lib/messaging/messaging.h"
  29 #include "auth/gensec/gensec.h"
  30 #include "auth/credentials/credentials.h"
  31 #include "lib/global_contexts.h"
  32 #include "lib/util/idtree.h"
  33
  34 #undef DBGC_CLASS
  35 #define DBGC_CLASS DBGC_AUTH
  36
  37 static NTSTATUS make_auth4_context_s4(const struct auth_context *auth_context,
  38                                       TALLOC_CTX *mem_ctx,
  39                                       struct auth4_context **auth4_context);
  40
  41 static struct idr_context *task_id_tree;
  42
  43 static int free_task_id(struct server_id *server_id)
  44 {
  45         idr_remove(task_id_tree, server_id->task_id);
  46         return 0;
  47 }
  48
  49 /* Return a server_id with a unique task_id element.  Free the
  50  * returned pointer to de-allocate the task_id via a talloc destructor
  51  * (ie, use talloc_free()) */
  52 static struct server_id *new_server_id_task(TALLOC_CTX *mem_ctx)
  53 {
  54         struct messaging_context *msg_ctx;
  55         struct server_id *server_id;
  56         int task_id;
  57         if (!task_id_tree) {
  58                 task_id_tree = idr_init(NULL);
  59                 if (!task_id_tree) {
  60                         return NULL;
  61                 }
  62         }
  63
  64         msg_ctx = global_messaging_context();
  65         if (msg_ctx == NULL) {
  66                 return NULL;
  67         }
  68
  69         server_id = talloc(mem_ctx, struct server_id);
  70
  71         if (!server_id) {
  72                 return NULL;
  73         }
  74         *server_id = messaging_server_id(msg_ctx);
  75
  76         /* 0 is the default server_id, so we need to start with 1 */
  77         task_id = idr_get_new_above(task_id_tree, server_id, 1, INT32_MAX);
  78
  79         if (task_id == -1) {
  80                 talloc_free(server_id);
  81                 return NULL;
  82         }
  83
  84         talloc_set_destructor(server_id, free_task_id);
  85         server_id->task_id = task_id;
  86         return server_id;
  87 }
  88
  89 /*
  90  * This module is not an ordinary authentication module.  It is really
  91  * a way to redirect the whole authentication and authorization stack
  92  * to use the source4 auth code, not a way to just handle NTLM
  93  * authentication.
  94  *
  95  * See the comments above each function for how that hook changes the
  96  * behaviour.
  97  */
  98
  99 /*
 100  * This hook is currently used by winbindd only, as all other NTLM
 101  * logins go via the hooks provided by make_auth4_context_s4() below.
 102  *
 103  * This is only left in case we find a way that it might become useful
 104  * in future.  Importantly, this routine returns the information
 105  * needed for a NETLOGON SamLogon, not what is needed to establish a
 106  * session.
 107  *
 108  * We expect we may use this hook in the source3/ winbind when this
 109  * services the AD DC.  It is tested via pdbtest.
 110  */
 111
 112 static NTSTATUS check_samba4_security(
 113         const struct auth_context *auth_context,
 114         void *my_private_data,
 115         TALLOC_CTX *mem_ctx,
 116         const struct auth_usersupplied_info *user_info,
 117         struct auth_serversupplied_info **pserver_info)
 118 {
 119         TALLOC_CTX *frame = talloc_stackframe();
 120         struct netr_SamInfo3 *info3 = NULL;
 121         NTSTATUS nt_status;
 122         struct auth_user_info_dc *user_info_dc;
 123         struct auth4_context *auth4_context;
 124         uint8_t authoritative = 1;
 125         struct auth_serversupplied_info *server_info = NULL;
 126
 127         nt_status = make_auth4_context_s4(auth_context, mem_ctx, &auth4_context);
 128         if (!NT_STATUS_IS_OK(nt_status)) {
 129                 TALLOC_FREE(frame);
 130                 goto done;
 131         }
 132
 133         nt_status = auth_context_set_challenge(auth4_context, auth_context->challenge.data, "auth_samba4");
 134         if (!NT_STATUS_IS_OK(nt_status)) {
 135                 TALLOC_FREE(auth4_context);
 136                 TALLOC_FREE(frame);
 137                 return nt_status;
 138         }
 139
 140         nt_status = auth_check_password(auth4_context, auth4_context, user_info,
 141                                         &user_info_dc, &authoritative);
 142         if (!NT_STATUS_IS_OK(nt_status)) {
 143                 if (NT_STATUS_EQUAL(nt_status, NT_STATUS_NO_SUCH_USER) &&
 144                                     authoritative == 0)
 145                 {
 146                         nt_status = NT_STATUS_NOT_IMPLEMENTED;
 147                 }
 148                 TALLOC_FREE(auth4_context);
 149                 TALLOC_FREE(frame);
 150                 return nt_status;
 151         }
 152
 153         nt_status = auth_convert_user_info_dc_saminfo3(mem_ctx,
 154                                                        user_info_dc,
 155                                                        AUTH_INCLUDE_RESOURCE_GROUPS,
 156                                                        &info3,
 157                                                        NULL);
 158         if (NT_STATUS_IS_OK(nt_status)) {
 159                 /* We need the strings from the server_info to be valid as long as the info3 is around */
 160                 talloc_steal(info3, user_info_dc);
 161         }
 162         talloc_free(auth4_context);
 163
 164         if (!NT_STATUS_IS_OK(nt_status)) {
 165                 goto done;
 166         }
 167
 168         if (user_info->flags & USER_INFO_INFO3_AND_NO_AUTHZ) {
 169                 server_info = make_server_info(mem_ctx);
 170                 if (server_info == NULL) {
 171                         nt_status = NT_STATUS_NO_MEMORY;
 172                         goto done;
 173                 }
 174                 server_info->info3 = talloc_move(server_info, &info3);
 175         } else {
 176                 nt_status = make_server_info_info3(
 177                         mem_ctx,
 178                         user_info->client.account_name,
 179                         user_info->mapped.domain_name,
 180                         &server_info,
 181                         info3);
 182                 if (!NT_STATUS_IS_OK(nt_status)) {
 183                         DEBUG(10, ("make_server_info_info3 failed: %s\n",
 184                                    nt_errstr(nt_status)));
 185                         goto done;
 186                 }
 187         }
 188
 189         *pserver_info = server_info;
 190         nt_status = NT_STATUS_OK;
 191
 192  done:
 193         TALLOC_FREE(frame);
 194         return nt_status;
 195 }
 196
 197 /*
 198  * Hook to allow the source4 set of GENSEC modules to handle
 199  * blob-based authentication mechanisms, without directly linking the
 200  * mechanism code.
 201  *
 202  * This may eventually go away, when the GSSAPI acceptors are merged,
 203  * when we will just rely on the make_auth4_context_s4 hook instead.
 204  *
 205  * Even for NTLMSSP, which has a common module, significant parts of
 206  * the behaviour are overridden here, because it uses the source4 NTLM
 207  * stack and the source4 mapping between the PAC/SamLogon response and
 208  * the local token.
 209  *
 210  * It is important to override all this to ensure that the exact same
 211  * token is generated and used in the SMB and LDAP servers, for NTLM
 212  * and for Kerberos.
 213  */
 214 static NTSTATUS prepare_gensec(const struct auth_context *auth_context,
 215                                TALLOC_CTX *mem_ctx,
 216                                struct gensec_security **gensec_context)
 217 {
 218         NTSTATUS status;
 219         struct loadparm_context *lp_ctx;
 220         struct tevent_context *event_ctx;
 221         TALLOC_CTX *frame = talloc_stackframe();
 222         struct gensec_security *gensec_ctx;
 223         struct imessaging_context *msg_ctx;
 224         struct cli_credentials *server_credentials;
 225         struct server_id *server_id;
 226
 227         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 228         if (lp_ctx == NULL) {
 229                 DEBUG(1, ("loadparm_init_s3 failed\n"));
 230                 TALLOC_FREE(frame);
 231                 return NT_STATUS_INVALID_SERVER_STATE;
 232         }
 233         event_ctx = s4_event_context_init(frame);
 234         if (event_ctx == NULL) {
 235                 DEBUG(1, ("s4_event_context_init failed\n"));
 236                 TALLOC_FREE(frame);
 237                 return NT_STATUS_INVALID_SERVER_STATE;
 238         }
 239
 240         server_id = new_server_id_task(frame);
 241         if (server_id == NULL) {
 242                 DEBUG(1, ("new_server_id_task failed\n"));
 243                 TALLOC_FREE(frame);
 244                 return NT_STATUS_INVALID_SERVER_STATE;
 245         }
 246
 247         msg_ctx = imessaging_init_discard_incoming(frame,
 248                                   lp_ctx,
 249                                   *server_id,
 250                                   event_ctx);
 251         if (msg_ctx == NULL) {
 252                 DEBUG(1, ("imessaging_init_discard_incoming failed\n"));
 253                 TALLOC_FREE(frame);
 254                 return NT_STATUS_INVALID_SERVER_STATE;
 255         }
 256
 257         talloc_reparent(frame, msg_ctx, server_id);
 258
 259         server_credentials
 260                 = cli_credentials_init_server(frame, lp_ctx);
 261         if (!server_credentials) {
 262                 DEBUG(1, ("Failed to init server credentials\n"));
 263                 TALLOC_FREE(frame);
 264                 return NT_STATUS_INVALID_SERVER_STATE;
 265         }
 266
 267         status = samba_server_gensec_start(mem_ctx,
 268                                            event_ctx, msg_ctx,
 269                                            lp_ctx, server_credentials, "cifs",
 270                                            &gensec_ctx);
 271         if (!NT_STATUS_IS_OK(status)) {
 272                 DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
 273                 TALLOC_FREE(frame);
 274                 return status;
 275         }
 276
 277         talloc_reparent(frame, gensec_ctx, msg_ctx);
 278         talloc_reparent(frame, gensec_ctx, event_ctx);
 279         talloc_reparent(frame, gensec_ctx, lp_ctx);
 280         talloc_reparent(frame, gensec_ctx, server_credentials);
 281
 282         gensec_want_feature(gensec_ctx, GENSEC_FEATURE_SESSION_KEY);
 283         gensec_want_feature(gensec_ctx, GENSEC_FEATURE_UNIX_TOKEN);
 284
 285         *gensec_context = gensec_ctx;
 286         TALLOC_FREE(frame);
 287         return status;
 288 }
 289
 290 /*
 291  * Hook to allow handling of NTLM authentication for AD operation
 292  * without directly linking the s4 auth stack
 293  *
 294  * This ensures we use the source4 authentication stack, as well as
 295  * the authorization stack to create the user's token.  This ensures
 296  * consistency between NTLM logins and NTLMSSP logins, as NTLMSSP is
 297  * handled by the hook above.
 298  */
 299 static NTSTATUS make_auth4_context_s4(const struct auth_context *auth_context,
 300                                       TALLOC_CTX *mem_ctx,
 301                                       struct auth4_context **auth4_context)
 302 {
 303         NTSTATUS status;
 304         struct loadparm_context *lp_ctx;
 305         struct tevent_context *event_ctx;
 306         TALLOC_CTX *frame = talloc_stackframe();
 307         struct imessaging_context *msg_ctx;
 308         struct server_id *server_id;
 309
 310         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 311         if (lp_ctx == NULL) {
 312                 DEBUG(1, ("loadparm_init_s3 failed\n"));
 313                 TALLOC_FREE(frame);
 314                 return NT_STATUS_INVALID_SERVER_STATE;
 315         }
 316         event_ctx = s4_event_context_init(frame);
 317         if (event_ctx == NULL) {
 318                 DEBUG(1, ("s4_event_context_init failed\n"));
 319                 TALLOC_FREE(frame);
 320                 return NT_STATUS_INVALID_SERVER_STATE;
 321         }
 322
 323         server_id = new_server_id_task(frame);
 324         if (server_id == NULL) {
 325                 DEBUG(1, ("new_server_id_task failed\n"));
 326                 TALLOC_FREE(frame);
 327                 return NT_STATUS_INVALID_SERVER_STATE;
 328         }
 329
 330         msg_ctx = imessaging_init_discard_incoming(frame,
 331                                   lp_ctx,
 332                                   *server_id,
 333                                   event_ctx);
 334         if (msg_ctx == NULL) {
 335                 DEBUG(1, ("imessaging_init_discard_incoming failed\n"));
 336                 TALLOC_FREE(frame);
 337                 return NT_STATUS_INVALID_SERVER_STATE;
 338         }
 339         talloc_reparent(frame, msg_ctx, server_id);
 340
 341         /* Allow forcing a specific auth4 module */
 342         if (!auth_context->forced_samba4_methods) {
 343                 status = auth_context_create(mem_ctx,
 344                                              event_ctx,
 345                                              msg_ctx,
 346                                              lp_ctx,
 347                                              auth4_context);
 348         } else {
 349                 const char * const *forced_auth_methods = (const char * const *)str_list_make(mem_ctx, auth_context->forced_samba4_methods, NULL);
 350                 status = auth_context_create_methods(mem_ctx, forced_auth_methods, event_ctx, msg_ctx, lp_ctx, NULL, auth4_context);
 351         }
 352         if (!NT_STATUS_IS_OK(status)) {
 353                 DEBUG(1, ("Failed to start auth server code: %s\n", nt_errstr(status)));
 354                 TALLOC_FREE(frame);
 355                 return status;
 356         }
 357
 358         talloc_reparent(frame, *auth4_context, msg_ctx);
 359         talloc_reparent(frame, *auth4_context, event_ctx);
 360         talloc_reparent(frame, *auth4_context, lp_ctx);
 361
 362         TALLOC_FREE(frame);
 363         return status;
 364 }
 365
 366 /* module initialisation */
 367 static NTSTATUS auth_init_samba4(struct auth_context *auth_context,
 368                                  const char *param,
 369                                  struct auth_methods **auth_method)
 370 {
 371         struct auth_methods *result;
 372
 373         gensec_init();
 374
 375         result = talloc_zero(auth_context, struct auth_methods);
 376         if (result == NULL) {
 377                 return NT_STATUS_NO_MEMORY;
 378         }
 379         result->name = "samba4";
 380         result->auth = check_samba4_security;
 381         result->prepare_gensec = prepare_gensec;
 382         result->make_auth4_context = make_auth4_context_s4;
 383
 384         if (param && *param) {
 385                 auth_context->forced_samba4_methods = talloc_strdup(result, param);
 386                 if (!auth_context->forced_samba4_methods) {
 387                         return NT_STATUS_NO_MEMORY;
 388                 }
 389         }
 390
 391         *auth_method = result;
 392         return NT_STATUS_OK;
 393 }
 394
 395 NTSTATUS auth_samba4_init(TALLOC_CTX *mem_ctx);
 396 NTSTATUS auth_samba4_init(TALLOC_CTX *mem_ctx)
 397 {
 398         smb_register_auth(AUTH_INTERFACE_VERSION, "samba4",
 399                           auth_init_samba4);
 400         return NT_STATUS_OK;
 401 }