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 = server_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
 122         nt_status = make_auth4_context_s4(auth_context, mem_ctx, &auth4_context);
 123         if (!NT_STATUS_IS_OK(nt_status)) {
 124                 TALLOC_FREE(frame);
 125                 goto done;
 126         }
 127
 128         nt_status = auth_context_set_challenge(auth4_context, auth_context->challenge.data, "auth_samba4");
 129         if (!NT_STATUS_IS_OK(nt_status)) {
 130                 TALLOC_FREE(auth4_context);
 131                 TALLOC_FREE(frame);
 132                 return nt_status;
 133         }
 134
 135         nt_status = auth_check_password(auth4_context, auth4_context, user_info, &user_info_dc);
 136         if (!NT_STATUS_IS_OK(nt_status)) {
 137                 TALLOC_FREE(auth4_context);
 138                 TALLOC_FREE(frame);
 139                 return nt_status;
 140         }
 141
 142         nt_status = auth_convert_user_info_dc_saminfo3(mem_ctx,
 143                                                        user_info_dc,
 144                                                        &info3);
 145         if (NT_STATUS_IS_OK(nt_status)) {
 146                 /* We need the strings from the server_info to be valid as long as the info3 is around */
 147                 talloc_steal(info3, user_info_dc);
 148         }
 149         talloc_free(auth4_context);
 150
 151         if (!NT_STATUS_IS_OK(nt_status)) {
 152                 goto done;
 153         }
 154
 155         if (user_info->flags & USER_INFO_INFO3_AND_NO_AUTHZ) {
 156                 *server_info = make_server_info(mem_ctx);
 157                 if (*server_info == NULL) {
 158                         nt_status = NT_STATUS_NO_MEMORY;
 159                         goto done;
 160                 }
 161                 (*server_info)->info3 = talloc_steal(*server_info, info3);
 162
 163         } else {
 164                 nt_status = make_server_info_info3(mem_ctx, user_info->client.account_name,
 165                                                    user_info->mapped.domain_name, server_info,
 166                                                    info3);
 167                 if (!NT_STATUS_IS_OK(nt_status)) {
 168                         DEBUG(10, ("make_server_info_info3 failed: %s\n",
 169                                    nt_errstr(nt_status)));
 170                         goto done;
 171                 }
 172         }
 173
 174         nt_status = NT_STATUS_OK;
 175
 176  done:
 177         TALLOC_FREE(frame);
 178         return nt_status;
 179 }
 180
 181 /*
 182  * Hook to allow the source4 set of GENSEC modules to handle
 183  * blob-based authentication mechanisms, without directly linking the
 184  * mechanism code.
 185  *
 186  * This may eventually go away, when the GSSAPI acceptors are merged,
 187  * when we will just rely on the make_auth4_context_s4 hook instead.
 188  *
 189  * Even for NTLMSSP, which has a common module, significant parts of
 190  * the behaviour are overridden here, because it uses the source4 NTLM
 191  * stack and the source4 mapping between the PAC/SamLogon response and
 192  * the local token.
 193  *
 194  * It is important to override all this to ensure that the exact same
 195  * token is generated and used in the SMB and LDAP servers, for NTLM
 196  * and for Kerberos.
 197  */
 198 static NTSTATUS prepare_gensec(const struct auth_context *auth_context,
 199                                TALLOC_CTX *mem_ctx,
 200                                struct gensec_security **gensec_context)
 201 {
 202         NTSTATUS status;
 203         struct loadparm_context *lp_ctx;
 204         struct tevent_context *event_ctx;
 205         TALLOC_CTX *frame = talloc_stackframe();
 206         struct gensec_security *gensec_ctx;
 207         struct imessaging_context *msg_ctx;
 208         struct cli_credentials *server_credentials;
 209         struct server_id *server_id;
 210
 211         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 212         if (lp_ctx == NULL) {
 213                 DEBUG(1, ("loadparm_init_s3 failed\n"));
 214                 TALLOC_FREE(frame);
 215                 return NT_STATUS_INVALID_SERVER_STATE;
 216         }
 217         event_ctx = s4_event_context_init(frame);
 218         if (event_ctx == NULL) {
 219                 DEBUG(1, ("s4_event_context_init failed\n"));
 220                 TALLOC_FREE(frame);
 221                 return NT_STATUS_INVALID_SERVER_STATE;
 222         }
 223
 224         server_id = new_server_id_task(frame);
 225         if (server_id == NULL) {
 226                 DEBUG(1, ("new_server_id_task failed\n"));
 227                 TALLOC_FREE(frame);
 228                 return NT_STATUS_INVALID_SERVER_STATE;
 229         }
 230
 231         msg_ctx = imessaging_init(frame,
 232                                   lp_ctx,
 233                                   *server_id,
 234                                   event_ctx, true);
 235         if (msg_ctx == NULL) {
 236                 DEBUG(1, ("imessaging_init failed\n"));
 237                 TALLOC_FREE(frame);
 238                 return NT_STATUS_INVALID_SERVER_STATE;
 239         }
 240
 241         talloc_reparent(frame, msg_ctx, server_id);
 242
 243         server_credentials
 244                 = cli_credentials_init(frame);
 245         if (!server_credentials) {
 246                 DEBUG(1, ("Failed to init server credentials"));
 247                 TALLOC_FREE(frame);
 248                 return NT_STATUS_INVALID_SERVER_STATE;
 249         }
 250
 251         cli_credentials_set_conf(server_credentials, lp_ctx);
 252         status = cli_credentials_set_machine_account(server_credentials, lp_ctx);
 253         if (!NT_STATUS_IS_OK(status)) {
 254                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
 255                 talloc_free(server_credentials);
 256                 server_credentials = NULL;
 257         }
 258
 259         status = samba_server_gensec_start(mem_ctx,
 260                                            event_ctx, msg_ctx,
 261                                            lp_ctx, server_credentials, "cifs",
 262                                            &gensec_ctx);
 263         if (!NT_STATUS_IS_OK(status)) {
 264                 DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
 265                 TALLOC_FREE(frame);
 266                 return status;
 267         }
 268
 269         talloc_reparent(frame, gensec_ctx, msg_ctx);
 270         talloc_reparent(frame, gensec_ctx, event_ctx);
 271         talloc_reparent(frame, gensec_ctx, lp_ctx);
 272         talloc_reparent(frame, gensec_ctx, server_credentials);
 273
 274         gensec_want_feature(gensec_ctx, GENSEC_FEATURE_SESSION_KEY);
 275         gensec_want_feature(gensec_ctx, GENSEC_FEATURE_UNIX_TOKEN);
 276
 277         *gensec_context = gensec_ctx;
 278         TALLOC_FREE(frame);
 279         return status;
 280 }
 281
 282 /*
 283  * Hook to allow handling of NTLM authentication for AD operation
 284  * without directly linking the s4 auth stack
 285  *
 286  * This ensures we use the source4 authentication stack, as well as
 287  * the authorization stack to create the user's token.  This ensures
 288  * consistency between NTLM logins and NTLMSSP logins, as NTLMSSP is
 289  * handled by the hook above.
 290  */
 291 static NTSTATUS make_auth4_context_s4(const struct auth_context *auth_context,
 292                                       TALLOC_CTX *mem_ctx,
 293                                       struct auth4_context **auth4_context)
 294 {
 295         NTSTATUS status;
 296         struct loadparm_context *lp_ctx;
 297         struct tevent_context *event_ctx;
 298         TALLOC_CTX *frame = talloc_stackframe();
 299         struct imessaging_context *msg_ctx;
 300         struct server_id *server_id;
 301
 302         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 303         if (lp_ctx == NULL) {
 304                 DEBUG(1, ("loadparm_init_s3 failed\n"));
 305                 TALLOC_FREE(frame);
 306                 return NT_STATUS_INVALID_SERVER_STATE;
 307         }
 308         event_ctx = s4_event_context_init(frame);
 309         if (event_ctx == NULL) {
 310                 DEBUG(1, ("s4_event_context_init failed\n"));
 311                 TALLOC_FREE(frame);
 312                 return NT_STATUS_INVALID_SERVER_STATE;
 313         }
 314
 315         server_id = new_server_id_task(frame);
 316         if (server_id == NULL) {
 317                 DEBUG(1, ("new_server_id_task failed\n"));
 318                 TALLOC_FREE(frame);
 319                 return NT_STATUS_INVALID_SERVER_STATE;
 320         }
 321
 322         msg_ctx = imessaging_init(frame,
 323                                   lp_ctx,
 324                                   *server_id,
 325                                   event_ctx, true);
 326         if (msg_ctx == NULL) {
 327                 DEBUG(1, ("imessaging_init failed\n"));
 328                 TALLOC_FREE(frame);
 329                 return NT_STATUS_INVALID_SERVER_STATE;
 330         }
 331         talloc_reparent(frame, msg_ctx, server_id);
 332
 333         /* Allow forcing a specific auth4 module */
 334         if (!auth_context->forced_samba4_methods) {
 335                 status = auth_context_create(mem_ctx,
 336                                              event_ctx,
 337                                              msg_ctx,
 338                                              lp_ctx,
 339                                              auth4_context);
 340         } else {
 341                 const char * const *forced_auth_methods = (const char * const *)str_list_make(mem_ctx, auth_context->forced_samba4_methods, NULL);
 342                 status = auth_context_create_methods(mem_ctx, forced_auth_methods, event_ctx, msg_ctx, lp_ctx, NULL, auth4_context);
 343         }
 344         if (!NT_STATUS_IS_OK(status)) {
 345                 DEBUG(1, ("Failed to start auth server code: %s\n", nt_errstr(status)));
 346                 TALLOC_FREE(frame);
 347                 return status;
 348         }
 349
 350         talloc_reparent(frame, *auth4_context, msg_ctx);
 351         talloc_reparent(frame, *auth4_context, event_ctx);
 352         talloc_reparent(frame, *auth4_context, lp_ctx);
 353
 354         TALLOC_FREE(frame);
 355         return status;
 356 }
 357
 358 /* module initialisation */
 359 static NTSTATUS auth_init_samba4(struct auth_context *auth_context,
 360                                     const char *param,
 361                                     auth_methods **auth_method)
 362 {
 363         struct auth_methods *result;
 364
 365         gensec_init();
 366
 367         result = talloc_zero(auth_context, struct auth_methods);
 368         if (result == NULL) {
 369                 return NT_STATUS_NO_MEMORY;
 370         }
 371         result->name = "samba4";
 372         result->auth = check_samba4_security;
 373         result->prepare_gensec = prepare_gensec;
 374         result->make_auth4_context = make_auth4_context_s4;
 375         result->flags = AUTH_METHOD_LOCAL_SAM;
 376
 377         if (param && *param) {
 378                 auth_context->forced_samba4_methods = talloc_strdup(result, param);
 379                 if (!auth_context->forced_samba4_methods) {
 380                         return NT_STATUS_NO_MEMORY;
 381                 }
 382         }
 383
 384         *auth_method = result;
 385         return NT_STATUS_OK;
 386 }
 387
 388 NTSTATUS auth_samba4_init(void);
 389 NTSTATUS auth_samba4_init(void)
 390 {
 391         smb_register_auth(AUTH_INTERFACE_VERSION, "samba4",
 392                           auth_init_samba4);
 393         return NT_STATUS_OK;
 394 }