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