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