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 "source4/auth/auth.h"
  24 #include "auth/auth_sam_reply.h"
  25 #include "param/param.h"
  26 #include "source4/lib/events/events.h"
  27 #include "source4/lib/messaging/messaging.h"
  28 #include "auth/gensec/gensec.h"
  29 #include "auth/credentials/credentials.h"
  30
  31 #undef DBGC_CLASS
  32 #define DBGC_CLASS DBGC_AUTH
  33
  34 static NTSTATUS make_auth4_context_s4(const struct auth_context *auth_context,
  35                                       TALLOC_CTX *mem_ctx,
  36                                       struct auth4_context **auth4_context);
  37
  38 static struct idr_context *task_id_tree;
  39
  40 static int free_task_id(struct server_id *server_id)
  41 {
  42         idr_remove(task_id_tree, server_id->task_id);
  43         return 0;
  44 }
  45
  46 /* Return a server_id with a unique task_id element.  Free the
  47  * returned pointer to de-allocate the task_id via a talloc destructor
  48  * (ie, use talloc_free()) */
  49 static struct server_id *new_server_id_task(TALLOC_CTX *mem_ctx)
  50 {
  51         struct server_id *server_id;
  52         int task_id;
  53         if (!task_id_tree) {
  54                 task_id_tree = idr_init(NULL);
  55                 if (!task_id_tree) {
  56                         return NULL;
  57                 }
  58         }
  59
  60         server_id = talloc(mem_ctx, struct server_id);
  61
  62         if (!server_id) {
  63                 return NULL;
  64         }
  65         *server_id = procid_self();
  66
  67         /* 0 is the default server_id, so we need to start with 1 */
  68         task_id = idr_get_new_above(task_id_tree, server_id, 1, INT32_MAX);
  69
  70         if (task_id == -1) {
  71                 talloc_free(server_id);
  72                 return NULL;
  73         }
  74
  75         talloc_set_destructor(server_id, free_task_id);
  76         server_id->task_id = task_id;
  77         return server_id;
  78 }
  79
  80 /*
  81  * This module is not an ordinary authentication module.  It is really
  82  * a way to redirect the whole authentication and authorization stack
  83  * to use the source4 auth code, not a way to just handle NTLM
  84  * authentication.
  85  *
  86  * See the comments above each function for how that hook changes the
  87  * behaviour.
  88  */
  89
  90 /*
  91  * This hook is currently used by winbindd only, as all other NTLM
  92  * logins go via the hooks provided by make_auth4_context_s4() below.
  93  *
  94  * This is only left in case we find a way that it might become useful
  95  * in future.  Importantly, this routine returns the information
  96  * needed for a NETLOGON SamLogon, not what is needed to establish a
  97  * session.
  98  *
  99  * We expect we may use this hook in the source3/ winbind when this
 100  * services the AD DC.  It is tested via pdbtest.
 101  */
 102
 103 static NTSTATUS check_samba4_security(const struct auth_context *auth_context,
 104                                       void *my_private_data,
 105                                       TALLOC_CTX *mem_ctx,
 106                                       const struct auth_usersupplied_info *user_info,
 107                                       struct auth_serversupplied_info **server_info)
 108 {
 109         TALLOC_CTX *frame = talloc_stackframe();
 110         struct netr_SamInfo3 *info3 = NULL;
 111         NTSTATUS nt_status;
 112         struct auth_user_info_dc *user_info_dc;
 113         struct auth4_context *auth4_context;
 114
 115         nt_status = make_auth4_context_s4(auth_context, mem_ctx, &auth4_context);
 116         if (!NT_STATUS_IS_OK(nt_status)) {
 117                 TALLOC_FREE(frame);
 118                 goto done;
 119         }
 120
 121         nt_status = auth_context_set_challenge(auth4_context, auth_context->challenge.data, "auth_samba4");
 122         if (!NT_STATUS_IS_OK(nt_status)) {
 123                 TALLOC_FREE(auth4_context);
 124                 TALLOC_FREE(frame);
 125                 return nt_status;
 126         }
 127
 128         nt_status = auth_check_password(auth4_context, auth4_context, user_info, &user_info_dc);
 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_convert_user_info_dc_saminfo3(mem_ctx,
 136                                                        user_info_dc,
 137                                                        &info3);
 138         if (NT_STATUS_IS_OK(nt_status)) {
 139                 /* We need the strings from the server_info to be valid as long as the info3 is around */
 140                 talloc_steal(info3, user_info_dc);
 141         }
 142         talloc_free(auth4_context);
 143
 144         if (!NT_STATUS_IS_OK(nt_status)) {
 145                 goto done;
 146         }
 147
 148         if (user_info->flags & USER_INFO_INFO3_AND_NO_AUTHZ) {
 149                 *server_info = make_server_info(mem_ctx);
 150                 if (*server_info == NULL) {
 151                         nt_status = NT_STATUS_NO_MEMORY;
 152                         goto done;
 153                 }
 154                 (*server_info)->info3 = talloc_steal(*server_info, info3);
 155
 156         } else {
 157                 nt_status = make_server_info_info3(mem_ctx, user_info->client.account_name,
 158                                                    user_info->mapped.domain_name, server_info,
 159                                                    info3);
 160                 if (!NT_STATUS_IS_OK(nt_status)) {
 161                         DEBUG(10, ("make_server_info_info3 failed: %s\n",
 162                                    nt_errstr(nt_status)));
 163                         goto done;
 164                 }
 165         }
 166
 167         nt_status = NT_STATUS_OK;
 168
 169  done:
 170         TALLOC_FREE(frame);
 171         return nt_status;
 172 }
 173
 174 /*
 175  * Hook to allow the source4 set of GENSEC modules to handle
 176  * blob-based authentication mechanisms, without directly linking the
 177  * mechanism code.
 178  *
 179  * This may eventually go away, when the GSSAPI acceptors are merged,
 180  * when we will just rely on the make_auth4_context_s4 hook instead.
 181  *
 182  * Even for NTLMSSP, which has a common module, significant parts of
 183  * the behaviour are overridden here, because it uses the source4 NTLM
 184  * stack and the source4 mapping between the PAC/SamLogon response and
 185  * the local token.
 186  *
 187  * It is important to override all this to ensure that the exact same
 188  * token is generated and used in the SMB and LDAP servers, for NTLM
 189  * and for Kerberos.
 190  */
 191 static NTSTATUS prepare_gensec(const struct auth_context *auth_context,
 192                                TALLOC_CTX *mem_ctx,
 193                                struct gensec_security **gensec_context)
 194 {
 195         NTSTATUS status;
 196         struct loadparm_context *lp_ctx;
 197         struct tevent_context *event_ctx;
 198         TALLOC_CTX *frame = talloc_stackframe();
 199         struct gensec_security *gensec_ctx;
 200         struct imessaging_context *msg_ctx;
 201         struct cli_credentials *server_credentials;
 202         struct server_id *server_id;
 203
 204         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 205         if (lp_ctx == NULL) {
 206                 DEBUG(1, ("loadparm_init_s3 failed\n"));
 207                 TALLOC_FREE(frame);
 208                 return NT_STATUS_INVALID_SERVER_STATE;
 209         }
 210         event_ctx = s4_event_context_init(frame);
 211         if (event_ctx == NULL) {
 212                 DEBUG(1, ("s4_event_context_init failed\n"));
 213                 TALLOC_FREE(frame);
 214                 return NT_STATUS_INVALID_SERVER_STATE;
 215         }
 216
 217         server_id = new_server_id_task(frame);
 218         if (server_id == NULL) {
 219                 DEBUG(1, ("new_server_id_task failed\n"));
 220                 TALLOC_FREE(frame);
 221                 return NT_STATUS_INVALID_SERVER_STATE;
 222         }
 223
 224         msg_ctx = imessaging_init(frame,
 225                                   lp_ctx,
 226                                   *server_id,
 227                                   event_ctx, true);
 228         if (msg_ctx == NULL) {
 229                 DEBUG(1, ("imessaging_init failed\n"));
 230                 TALLOC_FREE(frame);
 231                 return NT_STATUS_INVALID_SERVER_STATE;
 232         }
 233
 234         talloc_reparent(frame, msg_ctx, server_id);
 235
 236         server_credentials
 237                 = cli_credentials_init(frame);
 238         if (!server_credentials) {
 239                 DEBUG(1, ("Failed to init server credentials"));
 240                 TALLOC_FREE(frame);
 241                 return NT_STATUS_INVALID_SERVER_STATE;
 242         }
 243
 244         cli_credentials_set_conf(server_credentials, lp_ctx);
 245         status = cli_credentials_set_machine_account(server_credentials, lp_ctx);
 246         if (!NT_STATUS_IS_OK(status)) {
 247                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
 248                 talloc_free(server_credentials);
 249                 server_credentials = NULL;
 250         }
 251
 252         status = samba_server_gensec_start(mem_ctx,
 253                                            event_ctx, msg_ctx,
 254                                            lp_ctx, server_credentials, "cifs",
 255                                            &gensec_ctx);
 256         if (!NT_STATUS_IS_OK(status)) {
 257                 DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
 258                 TALLOC_FREE(frame);
 259                 return status;
 260         }
 261
 262         talloc_reparent(frame, gensec_ctx, msg_ctx);
 263         talloc_reparent(frame, gensec_ctx, event_ctx);
 264         talloc_reparent(frame, gensec_ctx, lp_ctx);
 265         talloc_reparent(frame, gensec_ctx, server_credentials);
 266
 267         gensec_want_feature(gensec_ctx, GENSEC_FEATURE_SESSION_KEY);
 268         gensec_want_feature(gensec_ctx, GENSEC_FEATURE_UNIX_TOKEN);
 269
 270         *gensec_context = gensec_ctx;
 271         TALLOC_FREE(frame);
 272         return status;
 273 }
 274
 275 /*
 276  * Hook to allow handling of NTLM authentication for AD operation
 277  * without directly linking the s4 auth stack
 278  *
 279  * This ensures we use the source4 authentication stack, as well as
 280  * the authorization stack to create the user's token.  This ensures
 281  * consistency between NTLM logins and NTLMSSP logins, as NTLMSSP is
 282  * handled by the hook above.
 283  */
 284 static NTSTATUS make_auth4_context_s4(const struct auth_context *auth_context,
 285                                       TALLOC_CTX *mem_ctx,
 286                                       struct auth4_context **auth4_context)
 287 {
 288         NTSTATUS status;
 289         struct loadparm_context *lp_ctx;
 290         struct tevent_context *event_ctx;
 291         TALLOC_CTX *frame = talloc_stackframe();
 292         struct imessaging_context *msg_ctx;
 293         struct server_id *server_id;
 294
 295         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 296         if (lp_ctx == NULL) {
 297                 DEBUG(1, ("loadparm_init_s3 failed\n"));
 298                 TALLOC_FREE(frame);
 299                 return NT_STATUS_INVALID_SERVER_STATE;
 300         }
 301         event_ctx = s4_event_context_init(frame);
 302         if (event_ctx == NULL) {
 303                 DEBUG(1, ("s4_event_context_init failed\n"));
 304                 TALLOC_FREE(frame);
 305                 return NT_STATUS_INVALID_SERVER_STATE;
 306         }
 307
 308         server_id = new_server_id_task(frame);
 309         if (server_id == NULL) {
 310                 DEBUG(1, ("new_server_id_task failed\n"));
 311                 TALLOC_FREE(frame);
 312                 return NT_STATUS_INVALID_SERVER_STATE;
 313         }
 314
 315         msg_ctx = imessaging_init(frame,
 316                                   lp_ctx,
 317                                   *server_id,
 318                                   event_ctx, true);
 319         if (msg_ctx == NULL) {
 320                 DEBUG(1, ("imessaging_init failed\n"));
 321                 TALLOC_FREE(frame);
 322                 return NT_STATUS_INVALID_SERVER_STATE;
 323         }
 324         talloc_reparent(frame, msg_ctx, server_id);
 325
 326         /* Allow forcing a specific auth4 module */
 327         if (!auth_context->forced_samba4_methods) {
 328                 status = auth_context_create(mem_ctx,
 329                                              event_ctx,
 330                                              msg_ctx,
 331                                              lp_ctx,
 332                                              auth4_context);
 333         } else {
 334                 const char * const *forced_auth_methods = (const char * const *)str_list_make(mem_ctx, auth_context->forced_samba4_methods, NULL);
 335                 status = auth_context_create_methods(mem_ctx, forced_auth_methods, event_ctx, msg_ctx, lp_ctx, NULL, auth4_context);
 336         }
 337         if (!NT_STATUS_IS_OK(status)) {
 338                 DEBUG(1, ("Failed to start auth server code: %s\n", nt_errstr(status)));
 339                 TALLOC_FREE(frame);
 340                 return status;
 341         }
 342
 343         talloc_reparent(frame, *auth4_context, msg_ctx);
 344         talloc_reparent(frame, *auth4_context, event_ctx);
 345         talloc_reparent(frame, *auth4_context, lp_ctx);
 346
 347         TALLOC_FREE(frame);
 348         return status;
 349 }
 350
 351 /* module initialisation */
 352 static NTSTATUS auth_init_samba4(struct auth_context *auth_context,
 353                                     const char *param,
 354                                     auth_methods **auth_method)
 355 {
 356         struct auth_methods *result;
 357
 358         gensec_init();
 359
 360         result = talloc_zero(auth_context, struct auth_methods);
 361         if (result == NULL) {
 362                 return NT_STATUS_NO_MEMORY;
 363         }
 364         result->name = "samba4";
 365         result->auth = check_samba4_security;
 366         result->prepare_gensec = prepare_gensec;
 367         result->make_auth4_context = make_auth4_context_s4;
 368         result->flags = AUTH_METHOD_LOCAL_SAM;
 369
 370         if (param && *param) {
 371                 auth_context->forced_samba4_methods = talloc_strdup(result, param);
 372                 if (!auth_context->forced_samba4_methods) {
 373                         return NT_STATUS_NO_MEMORY;
 374                 }
 375         }
 376
 377         *auth_method = result;
 378         return NT_STATUS_OK;
 379 }
 380
 381 NTSTATUS auth_samba4_init(void);
 382 NTSTATUS auth_samba4_init(void)
 383 {
 384         smb_register_auth(AUTH_INTERFACE_VERSION, "samba4",
 385                           auth_init_samba4);
 386         return NT_STATUS_OK;
 387 }