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 struct idr_context *task_id_tree;
  35
  36 static int free_task_id(struct server_id *server_id)
  37 {
  38         idr_remove(task_id_tree, server_id->task_id);
  39         return 0;
  40 }
  41
  42 /* Return a server_id with a unique task_id element.  Free the
  43  * returned pointer to de-allocate the task_id via a talloc destructor
  44  * (ie, use talloc_free()) */
  45 static struct server_id *new_server_id_task(TALLOC_CTX *mem_ctx)
  46 {
  47         struct server_id *server_id;
  48         int task_id;
  49         if (!task_id_tree) {
  50                 task_id_tree = idr_init(NULL);
  51                 if (!task_id_tree) {
  52                         return NULL;
  53                 }
  54         }
  55
  56         server_id = talloc(mem_ctx, struct server_id);
  57
  58         if (!server_id) {
  59                 return NULL;
  60         }
  61         *server_id = procid_self();
  62
  63         /* 0 is the default server_id, so we need to start with 1 */
  64         task_id = idr_get_new_above(task_id_tree, server_id, 1, INT32_MAX);
  65
  66         if (task_id == -1) {
  67                 talloc_free(server_id);
  68                 return NULL;
  69         }
  70
  71         talloc_set_destructor(server_id, free_task_id);
  72         server_id->task_id = task_id;
  73         return server_id;
  74 }
  75
  76 /*
  77  * This module is not an ordinary authentication module.  It is really
  78  * a way to redirect the whole authentication and authorization stack
  79  * to use the source4 auth code, not a way to just handle NTLM
  80  * authentication.
  81  *
  82  * See the comments above each function for how that hook changes the
  83  * behaviour.
  84  */
  85
  86 /*
  87  * This hook is currently unused, as all NTLM logins go via the hooks
  88  * provided by make_auth4_context_s4() below.
  89  *
  90  * This is only left in case we find a way that it might become useful
  91  * in future.  Importantly, this routine returns the information
  92  * needed for a NETLOGON SamLogon, not what is needed to establish a
  93  * session.
  94  *
  95  * We expect we may use this hook in the source3/ winbind when this
  96  * services the AD DC.  It is tested via pdbtest.
  97  */
  98
  99 static NTSTATUS check_samba4_security(const struct auth_context *auth_context,
 100                                       void *my_private_data,
 101                                       TALLOC_CTX *mem_ctx,
 102                                       const struct auth_usersupplied_info *user_info,
 103                                       struct auth_serversupplied_info **server_info)
 104 {
 105         TALLOC_CTX *frame = talloc_stackframe();
 106         struct netr_SamInfo3 *info3 = NULL;
 107         NTSTATUS nt_status;
 108         struct auth_user_info_dc *user_info_dc;
 109         struct auth4_context *auth4_context;
 110         struct loadparm_context *lp_ctx;
 111
 112         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 113         if (lp_ctx == NULL) {
 114                 DEBUG(10, ("loadparm_init_s3 failed\n"));
 115                 talloc_free(frame);
 116                 return NT_STATUS_INVALID_SERVER_STATE;
 117         }
 118
 119         /* We create a private tevent context here to avoid nested loops in
 120          * the s3 one, as that may not be expected */
 121         nt_status = auth_context_create(mem_ctx,
 122                                         s4_event_context_init(frame), NULL,
 123                                         lp_ctx,
 124                                         &auth4_context);
 125         NT_STATUS_NOT_OK_RETURN(nt_status);
 126
 127         nt_status = auth_context_set_challenge(auth4_context, auth_context->challenge.data, "auth_samba4");
 128         NT_STATUS_NOT_OK_RETURN_AND_FREE(nt_status, auth4_context);
 129
 130         nt_status = auth_check_password(auth4_context, auth4_context, user_info, &user_info_dc);
 131         NT_STATUS_NOT_OK_RETURN_AND_FREE(nt_status, auth4_context);
 132
 133         nt_status = auth_convert_user_info_dc_saminfo3(mem_ctx,
 134                                                        user_info_dc,
 135                                                        &info3);
 136         if (NT_STATUS_IS_OK(nt_status)) {
 137                 /* We need the strings from the server_info to be valid as long as the info3 is around */
 138                 talloc_steal(info3, user_info_dc);
 139         }
 140         talloc_free(auth4_context);
 141
 142         if (!NT_STATUS_IS_OK(nt_status)) {
 143                 goto done;
 144         }
 145
 146         nt_status = make_server_info_info3(mem_ctx, user_info->client.account_name,
 147                                            user_info->mapped.domain_name, server_info,
 148                                         info3);
 149         if (!NT_STATUS_IS_OK(nt_status)) {
 150                 DEBUG(10, ("make_server_info_info3 failed: %s\n",
 151                            nt_errstr(nt_status)));
 152                 TALLOC_FREE(frame);
 153                 return nt_status;
 154         }
 155
 156         nt_status = NT_STATUS_OK;
 157
 158  done:
 159         TALLOC_FREE(frame);
 160         return nt_status;
 161 }
 162
 163 /*
 164  * Hook to allow the source4 set of GENSEC modules to handle
 165  * blob-based authentication mechanisms, without directly linking the
 166  * mechanism code.
 167  *
 168  * This may eventually go away, when the GSSAPI acceptors are merged,
 169  * when we will just rely on the make_auth4_context_s4 hook instead.
 170  *
 171  * Even for NTLMSSP, which has a common module, significant parts of
 172  * the behaviour are overridden here, because it uses the source4 NTLM
 173  * stack and the source4 mapping between the PAC/SamLogon response and
 174  * the local token.
 175  *
 176  * It is important to override all this to ensure that the exact same
 177  * token is generated and used in the SMB and LDAP servers, for NTLM
 178  * and for Kerberos.
 179  */
 180 static NTSTATUS prepare_gensec(TALLOC_CTX *mem_ctx,
 181                                struct gensec_security **gensec_context)
 182 {
 183         NTSTATUS status;
 184         struct loadparm_context *lp_ctx;
 185         struct tevent_context *event_ctx;
 186         TALLOC_CTX *frame = talloc_stackframe();
 187         struct gensec_security *gensec_ctx;
 188         struct imessaging_context *msg_ctx;
 189         struct cli_credentials *server_credentials;
 190         struct server_id *server_id;
 191
 192         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 193         if (lp_ctx == NULL) {
 194                 DEBUG(1, ("loadparm_init_s3 failed\n"));
 195                 TALLOC_FREE(frame);
 196                 return NT_STATUS_INVALID_SERVER_STATE;
 197         }
 198         event_ctx = s4_event_context_init(frame);
 199         if (event_ctx == NULL) {
 200                 DEBUG(1, ("s4_event_context_init failed\n"));
 201                 TALLOC_FREE(frame);
 202                 return NT_STATUS_INVALID_SERVER_STATE;
 203         }
 204
 205         server_id = new_server_id_task(frame);
 206         if (server_id == NULL) {
 207                 DEBUG(1, ("new_server_id_task failed\n"));
 208                 TALLOC_FREE(frame);
 209                 return NT_STATUS_INVALID_SERVER_STATE;
 210         }
 211
 212         msg_ctx = imessaging_init(frame,
 213                                   lp_ctx,
 214                                   *server_id,
 215                                   event_ctx, true);
 216         if (msg_ctx == NULL) {
 217                 DEBUG(1, ("imessaging_init failed\n"));
 218                 TALLOC_FREE(frame);
 219                 return NT_STATUS_INVALID_SERVER_STATE;
 220         }
 221
 222         talloc_reparent(frame, msg_ctx, server_id);
 223
 224         server_credentials
 225                 = cli_credentials_init(frame);
 226         if (!server_credentials) {
 227                 DEBUG(1, ("Failed to init server credentials"));
 228                 TALLOC_FREE(frame);
 229                 return NT_STATUS_INVALID_SERVER_STATE;
 230         }
 231
 232         cli_credentials_set_conf(server_credentials, lp_ctx);
 233         status = cli_credentials_set_machine_account(server_credentials, lp_ctx);
 234         if (!NT_STATUS_IS_OK(status)) {
 235                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
 236                 talloc_free(server_credentials);
 237                 server_credentials = NULL;
 238         }
 239
 240         status = samba_server_gensec_start(mem_ctx,
 241                                            event_ctx, msg_ctx,
 242                                            lp_ctx, server_credentials, "cifs",
 243                                            &gensec_ctx);
 244         if (!NT_STATUS_IS_OK(status)) {
 245                 DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
 246                 TALLOC_FREE(frame);
 247                 return status;
 248         }
 249
 250         talloc_reparent(frame, gensec_ctx, msg_ctx);
 251         talloc_reparent(frame, gensec_ctx, event_ctx);
 252         talloc_reparent(frame, gensec_ctx, lp_ctx);
 253         talloc_reparent(frame, gensec_ctx, server_credentials);
 254
 255         gensec_want_feature(gensec_ctx, GENSEC_FEATURE_SESSION_KEY);
 256         gensec_want_feature(gensec_ctx, GENSEC_FEATURE_UNIX_TOKEN);
 257
 258         *gensec_context = gensec_ctx;
 259         TALLOC_FREE(frame);
 260         return status;
 261 }
 262
 263 /*
 264  * Hook to allow handling of NTLM authentication for AD operation
 265  * without directly linking the s4 auth stack
 266  *
 267  * This ensures we use the source4 authentication stack, as well as
 268  * the authorization stack to create the user's token.  This ensures
 269  * consistency between NTLM logins and NTLMSSP logins, as NTLMSSP is
 270  * handled by the hook above.
 271  */
 272 static NTSTATUS make_auth4_context_s4(TALLOC_CTX *mem_ctx,
 273                                       struct auth4_context **auth4_context)
 274 {
 275         NTSTATUS status;
 276         struct loadparm_context *lp_ctx;
 277         struct tevent_context *event_ctx;
 278         TALLOC_CTX *frame = talloc_stackframe();
 279         struct imessaging_context *msg_ctx;
 280         struct server_id *server_id;
 281
 282         lp_ctx = loadparm_init_s3(frame, loadparm_s3_helpers());
 283         if (lp_ctx == NULL) {
 284                 DEBUG(1, ("loadparm_init_s3 failed\n"));
 285                 TALLOC_FREE(frame);
 286                 return NT_STATUS_INVALID_SERVER_STATE;
 287         }
 288         event_ctx = s4_event_context_init(frame);
 289         if (event_ctx == NULL) {
 290                 DEBUG(1, ("s4_event_context_init failed\n"));
 291                 TALLOC_FREE(frame);
 292                 return NT_STATUS_INVALID_SERVER_STATE;
 293         }
 294
 295         server_id = new_server_id_task(frame);
 296         if (server_id == NULL) {
 297                 DEBUG(1, ("new_server_id_task failed\n"));
 298                 TALLOC_FREE(frame);
 299                 return NT_STATUS_INVALID_SERVER_STATE;
 300         }
 301
 302         msg_ctx = imessaging_init(frame,
 303                                   lp_ctx,
 304                                   *server_id,
 305                                   event_ctx, true);
 306         if (msg_ctx == NULL) {
 307                 DEBUG(1, ("imessaging_init failed\n"));
 308                 TALLOC_FREE(frame);
 309                 return NT_STATUS_INVALID_SERVER_STATE;
 310         }
 311         talloc_reparent(frame, msg_ctx, server_id);
 312
 313         status = auth_context_create(mem_ctx,
 314                                         event_ctx,
 315                                         msg_ctx,
 316                                         lp_ctx,
 317                                         auth4_context);
 318
 319         if (!NT_STATUS_IS_OK(status)) {
 320                 DEBUG(1, ("Failed to start auth server code: %s\n", nt_errstr(status)));
 321                 TALLOC_FREE(frame);
 322                 return status;
 323         }
 324
 325         talloc_reparent(frame, *auth4_context, msg_ctx);
 326         talloc_reparent(frame, *auth4_context, event_ctx);
 327         talloc_reparent(frame, *auth4_context, lp_ctx);
 328
 329         TALLOC_FREE(frame);
 330         return status;
 331 }
 332
 333 /* module initialisation */
 334 static NTSTATUS auth_init_samba4(struct auth_context *auth_context,
 335                                     const char *param,
 336                                     auth_methods **auth_method)
 337 {
 338         struct auth_methods *result;
 339
 340         gensec_init();
 341
 342         result = talloc_zero(auth_context, struct auth_methods);
 343         if (result == NULL) {
 344                 return NT_STATUS_NO_MEMORY;
 345         }
 346         result->name = "samba4";
 347         result->auth = check_samba4_security;
 348         result->prepare_gensec = prepare_gensec;
 349         result->make_auth4_context = make_auth4_context_s4;
 350
 351         *auth_method = result;
 352         return NT_STATUS_OK;
 353 }
 354
 355 NTSTATUS auth_samba4_init(void)
 356 {
 357         smb_register_auth(AUTH_INTERFACE_VERSION, "samba4",
 358                           auth_init_samba4);
 359         return NT_STATUS_OK;
 360 }