source4/auth/gensec/gensec_krb5.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Kerberos backend for GENSEC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004
   7    Copyright (C) Andrew Tridgell 2001
   8    Copyright (C) Luke Howard 2002-2003
   9    Copyright (C) Stefan Metzmacher 2004-2005
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 3 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  24 */
  25
  26 #include "includes.h"
  27 #include "system/kerberos.h"
  28 #include "auth/kerberos/kerberos.h"
  29 #include "auth/auth.h"
  30 #include "lib/tsocket/tsocket.h"
  31 #include "librpc/gen_ndr/dcerpc.h"
  32 #include "auth/credentials/credentials.h"
  33 #include "auth/credentials/credentials_krb5.h"
  34 #include "auth/kerberos/kerberos_credentials.h"
  35 #include "auth/gensec/gensec.h"
  36 #include "auth/gensec/gensec_internal.h"
  37 #include "auth/gensec/gensec_proto.h"
  38 #include "auth/gensec/gensec_toplevel_proto.h"
  39 #include "param/param.h"
  40 #include "auth/auth_sam_reply.h"
  41 #include "lib/util/util_net.h"
  42 #include "../lib/util/asn1.h"
  43 #include "auth/kerberos/pac_utils.h"
  44 #include "gensec_krb5_util.h"
  45
  46 _PUBLIC_ NTSTATUS gensec_krb5_init(void);
  47
  48 enum GENSEC_KRB5_STATE {
  49         GENSEC_KRB5_SERVER_START,
  50         GENSEC_KRB5_CLIENT_START,
  51         GENSEC_KRB5_CLIENT_MUTUAL_AUTH,
  52         GENSEC_KRB5_DONE
  53 };
  54
  55 struct gensec_krb5_state {
  56         enum GENSEC_KRB5_STATE state_position;
  57         struct smb_krb5_context *smb_krb5_context;
  58         krb5_auth_context auth_context;
  59         krb5_data enc_ticket;
  60         krb5_keyblock *keyblock;
  61         krb5_ticket *ticket;
  62         bool gssapi;
  63         krb5_flags ap_req_options;
  64 };
  65
  66 static int gensec_krb5_destroy(struct gensec_krb5_state *gensec_krb5_state)
  67 {
  68         if (!gensec_krb5_state->smb_krb5_context) {
  69                 /* We can't clean anything else up unless we started up this far */
  70                 return 0;
  71         }
  72         if (gensec_krb5_state->enc_ticket.length) {
  73                 kerberos_free_data_contents(gensec_krb5_state->smb_krb5_context->krb5_context,
  74                                             &gensec_krb5_state->enc_ticket);
  75         }
  76
  77         if (gensec_krb5_state->ticket) {
  78                 krb5_free_ticket(gensec_krb5_state->smb_krb5_context->krb5_context,
  79                                  gensec_krb5_state->ticket);
  80         }
  81
  82         /* ccache freed in a child destructor */
  83
  84         krb5_free_keyblock(gensec_krb5_state->smb_krb5_context->krb5_context,
  85                            gensec_krb5_state->keyblock);
  86
  87         if (gensec_krb5_state->auth_context) {
  88                 krb5_auth_con_free(gensec_krb5_state->smb_krb5_context->krb5_context,
  89                                    gensec_krb5_state->auth_context);
  90         }
  91
  92         return 0;
  93 }
  94
  95 static NTSTATUS gensec_krb5_start(struct gensec_security *gensec_security, bool gssapi)
  96 {
  97         krb5_error_code ret;
  98         struct gensec_krb5_state *gensec_krb5_state;
  99         struct cli_credentials *creds;
 100         const struct tsocket_address *tlocal_addr, *tremote_addr;
 101         krb5_address my_krb5_addr, peer_krb5_addr;
 102
 103         creds = gensec_get_credentials(gensec_security);
 104         if (!creds) {
 105                 return NT_STATUS_INVALID_PARAMETER;
 106         }
 107
 108         gensec_krb5_state = talloc(gensec_security, struct gensec_krb5_state);
 109         if (!gensec_krb5_state) {
 110                 return NT_STATUS_NO_MEMORY;
 111         }
 112
 113         gensec_security->private_data = gensec_krb5_state;
 114         gensec_krb5_state->smb_krb5_context = NULL;
 115         gensec_krb5_state->auth_context = NULL;
 116         gensec_krb5_state->ticket = NULL;
 117         ZERO_STRUCT(gensec_krb5_state->enc_ticket);
 118         gensec_krb5_state->keyblock = NULL;
 119         gensec_krb5_state->gssapi = gssapi;
 120
 121         talloc_set_destructor(gensec_krb5_state, gensec_krb5_destroy);
 122
 123         if (cli_credentials_get_krb5_context(creds,
 124                                              gensec_security->settings->lp_ctx, &gensec_krb5_state->smb_krb5_context)) {
 125                 talloc_free(gensec_krb5_state);
 126                 return NT_STATUS_INTERNAL_ERROR;
 127         }
 128
 129         ret = krb5_auth_con_init(gensec_krb5_state->smb_krb5_context->krb5_context, &gensec_krb5_state->auth_context);
 130         if (ret) {
 131                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_init failed (%s)\n",
 132                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 133                                                     ret, gensec_krb5_state)));
 134                 talloc_free(gensec_krb5_state);
 135                 return NT_STATUS_INTERNAL_ERROR;
 136         }
 137
 138         ret = krb5_auth_con_setflags(gensec_krb5_state->smb_krb5_context->krb5_context,
 139                                      gensec_krb5_state->auth_context,
 140                                      KRB5_AUTH_CONTEXT_DO_SEQUENCE);
 141         if (ret) {
 142                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_setflags failed (%s)\n",
 143                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 144                                                     ret, gensec_krb5_state)));
 145                 talloc_free(gensec_krb5_state);
 146                 return NT_STATUS_INTERNAL_ERROR;
 147         }
 148
 149         tlocal_addr = gensec_get_local_address(gensec_security);
 150         if (tlocal_addr) {
 151                 ssize_t socklen;
 152                 struct sockaddr_storage ss;
 153
 154                 socklen = tsocket_address_bsd_sockaddr(tlocal_addr,
 155                                 (struct sockaddr *) &ss,
 156                                 sizeof(struct sockaddr_storage));
 157                 if (socklen < 0) {
 158                         talloc_free(gensec_krb5_state);
 159                         return NT_STATUS_INTERNAL_ERROR;
 160                 }
 161                 ret = krb5_sockaddr2address(gensec_krb5_state->smb_krb5_context->krb5_context,
 162                                 (const struct sockaddr *) &ss, &my_krb5_addr);
 163                 if (ret) {
 164                         DEBUG(1,("gensec_krb5_start: krb5_sockaddr2address (local) failed (%s)\n",
 165                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 166                                                             ret, gensec_krb5_state)));
 167                         talloc_free(gensec_krb5_state);
 168                         return NT_STATUS_INTERNAL_ERROR;
 169                 }
 170         }
 171
 172         tremote_addr = gensec_get_remote_address(gensec_security);
 173         if (tremote_addr) {
 174                 ssize_t socklen;
 175                 struct sockaddr_storage ss;
 176
 177                 socklen = tsocket_address_bsd_sockaddr(tremote_addr,
 178                                 (struct sockaddr *) &ss,
 179                                 sizeof(struct sockaddr_storage));
 180                 if (socklen < 0) {
 181                         talloc_free(gensec_krb5_state);
 182                         return NT_STATUS_INTERNAL_ERROR;
 183                 }
 184                 ret = krb5_sockaddr2address(gensec_krb5_state->smb_krb5_context->krb5_context,
 185                                 (const struct sockaddr *) &ss, &peer_krb5_addr);
 186                 if (ret) {
 187                         DEBUG(1,("gensec_krb5_start: krb5_sockaddr2address (local) failed (%s)\n",
 188                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 189                                                             ret, gensec_krb5_state)));
 190                         talloc_free(gensec_krb5_state);
 191                         return NT_STATUS_INTERNAL_ERROR;
 192                 }
 193         }
 194
 195         ret = krb5_auth_con_setaddrs(gensec_krb5_state->smb_krb5_context->krb5_context,
 196                                      gensec_krb5_state->auth_context,
 197                                      tlocal_addr ? &my_krb5_addr : NULL,
 198                                      tremote_addr ? &peer_krb5_addr : NULL);
 199         if (ret) {
 200                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_setaddrs failed (%s)\n",
 201                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 202                                                     ret, gensec_krb5_state)));
 203                 talloc_free(gensec_krb5_state);
 204                 return NT_STATUS_INTERNAL_ERROR;
 205         }
 206
 207         return NT_STATUS_OK;
 208 }
 209
 210 static NTSTATUS gensec_krb5_common_server_start(struct gensec_security *gensec_security, bool gssapi)
 211 {
 212         NTSTATUS nt_status;
 213         struct gensec_krb5_state *gensec_krb5_state;
 214
 215         nt_status = gensec_krb5_start(gensec_security, gssapi);
 216         if (!NT_STATUS_IS_OK(nt_status)) {
 217                 return nt_status;
 218         }
 219
 220         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 221         gensec_krb5_state->state_position = GENSEC_KRB5_SERVER_START;
 222
 223         return NT_STATUS_OK;
 224 }
 225
 226 static NTSTATUS gensec_krb5_server_start(struct gensec_security *gensec_security)
 227 {
 228         return gensec_krb5_common_server_start(gensec_security, false);
 229 }
 230
 231 static NTSTATUS gensec_fake_gssapi_krb5_server_start(struct gensec_security *gensec_security)
 232 {
 233         return gensec_krb5_common_server_start(gensec_security, true);
 234 }
 235
 236 static NTSTATUS gensec_krb5_common_client_start(struct gensec_security *gensec_security, bool gssapi)
 237 {
 238         const char *hostname;
 239         struct gensec_krb5_state *gensec_krb5_state;
 240         NTSTATUS nt_status;
 241         hostname = gensec_get_target_hostname(gensec_security);
 242         if (!hostname) {
 243                 DEBUG(3, ("No hostname for target computer passed in, cannot use kerberos for this connection\n"));
 244                 return NT_STATUS_INVALID_PARAMETER;
 245         }
 246         if (is_ipaddress(hostname)) {
 247                 DEBUG(2, ("Cannot do krb5 to an IP address"));
 248                 return NT_STATUS_INVALID_PARAMETER;
 249         }
 250         if (strcmp(hostname, "localhost") == 0) {
 251                 DEBUG(2, ("krb5 to 'localhost' does not make sense"));
 252                 return NT_STATUS_INVALID_PARAMETER;
 253         }
 254
 255         nt_status = gensec_krb5_start(gensec_security, gssapi);
 256         if (!NT_STATUS_IS_OK(nt_status)) {
 257                 return nt_status;
 258         }
 259
 260         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 261         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_START;
 262         gensec_krb5_state->ap_req_options = AP_OPTS_USE_SUBKEY;
 263
 264         if (gensec_krb5_state->gssapi) {
 265                 /* The Fake GSSAPI model emulates Samba3, which does not do mutual authentication */
 266                 if (gensec_setting_bool(gensec_security->settings, "gensec_fake_gssapi_krb5", "mutual", false)) {
 267                         gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 268                 }
 269         } else {
 270                 /* The wrapping for KPASSWD (a user of the raw KRB5 API) should be mutually authenticated */
 271                 if (gensec_setting_bool(gensec_security->settings, "gensec_krb5", "mutual", true)) {
 272                         gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 273                 }
 274         }
 275         return NT_STATUS_OK;
 276 }
 277
 278 static NTSTATUS gensec_krb5_common_client_creds(struct gensec_security *gensec_security,
 279                                                 struct tevent_context *ev,
 280                                                 bool gssapi)
 281 {
 282         struct gensec_krb5_state *gensec_krb5_state;
 283         krb5_error_code ret;
 284         struct ccache_container *ccache_container;
 285         const char *error_string;
 286         const char *principal;
 287         const char *hostname;
 288         krb5_data in_data = { .length = 0 };
 289         krb5_data *in_data_p = NULL;
 290         struct tevent_context *previous_ev;
 291
 292         if (lpcfg_parm_bool(gensec_security->settings->lp_ctx,
 293                             NULL, "gensec_krb5", "send_authenticator_checksum", true)) {
 294                 in_data_p = &in_data;
 295         }
 296
 297         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 298
 299         principal = gensec_get_target_principal(gensec_security);
 300         hostname = gensec_get_target_hostname(gensec_security);
 301
 302         ret = cli_credentials_get_ccache(gensec_get_credentials(gensec_security),
 303                                          ev,
 304                                          gensec_security->settings->lp_ctx, &ccache_container, &error_string);
 305         switch (ret) {
 306         case 0:
 307                 break;
 308         case KRB5KDC_ERR_PREAUTH_FAILED:
 309         case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
 310                 return NT_STATUS_LOGON_FAILURE;
 311         case KRB5_KDC_UNREACH:
 312                 DEBUG(3, ("Cannot reach a KDC we require to contact %s: %s\n", principal, error_string));
 313                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 314         case KRB5_CC_NOTFOUND:
 315         case KRB5_CC_END:
 316                 DEBUG(3, ("Error preparing credentials we require to contact %s : %s\n", principal, error_string));
 317                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 318         default:
 319                 DEBUG(1, ("gensec_krb5_start: Aquiring initiator credentials failed: %s\n", error_string));
 320                 return NT_STATUS_UNSUCCESSFUL;
 321         }
 322
 323         /* Do this every time, in case we have weird recursive issues here */
 324         ret = smb_krb5_context_set_event_ctx(gensec_krb5_state->smb_krb5_context, ev, &previous_ev);
 325         if (ret != 0) {
 326                 DEBUG(1, ("gensec_krb5_start: Setting event context failed\n"));
 327                 return NT_STATUS_NO_MEMORY;
 328         }
 329         if (principal) {
 330                 krb5_principal target_principal;
 331                 ret = krb5_parse_name(gensec_krb5_state->smb_krb5_context->krb5_context, principal,
 332                                       &target_principal);
 333                 if (ret == 0) {
 334                         ret = krb5_mk_req_exact(gensec_krb5_state->smb_krb5_context->krb5_context,
 335                                                 &gensec_krb5_state->auth_context,
 336                                                 gensec_krb5_state->ap_req_options,
 337                                                 target_principal,
 338                                                 in_data_p, ccache_container->ccache,
 339                                                 &gensec_krb5_state->enc_ticket);
 340                         krb5_free_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
 341                                             target_principal);
 342                 }
 343         } else {
 344                 ret = krb5_mk_req(gensec_krb5_state->smb_krb5_context->krb5_context,
 345                                   &gensec_krb5_state->auth_context,
 346                                   gensec_krb5_state->ap_req_options,
 347                                   gensec_get_target_service(gensec_security),
 348                                   hostname,
 349                                   in_data_p, ccache_container->ccache,
 350                                   &gensec_krb5_state->enc_ticket);
 351         }
 352
 353         smb_krb5_context_remove_event_ctx(gensec_krb5_state->smb_krb5_context, previous_ev, ev);
 354
 355         switch (ret) {
 356         case 0:
 357                 return NT_STATUS_OK;
 358         case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
 359                 DEBUG(3, ("Server [%s] is not registered with our KDC: %s\n",
 360                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 361                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 362         case KRB5_KDC_UNREACH:
 363                 DEBUG(3, ("Cannot reach a KDC we require to contact host [%s]: %s\n",
 364                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 365                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 366         case KRB5KDC_ERR_PREAUTH_FAILED:
 367         case KRB5KRB_AP_ERR_TKT_EXPIRED:
 368         case KRB5_CC_END:
 369                 /* Too much clock skew - we will need to kinit to re-skew the clock */
 370         case KRB5KRB_AP_ERR_SKEW:
 371         case KRB5_KDCREP_SKEW:
 372         {
 373                 DEBUG(3, ("kerberos (mk_req) failed: %s\n",
 374                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 375                 /*fall through*/
 376         }
 377
 378         /* just don't print a message for these really ordinary messages */
 379         case KRB5_FCC_NOFILE:
 380         case KRB5_CC_NOTFOUND:
 381         case ENOENT:
 382
 383                 return NT_STATUS_UNSUCCESSFUL;
 384                 break;
 385
 386         default:
 387                 DEBUG(0, ("kerberos: %s\n",
 388                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 389                 return NT_STATUS_UNSUCCESSFUL;
 390         }
 391 }
 392
 393 static NTSTATUS gensec_krb5_client_start(struct gensec_security *gensec_security)
 394 {
 395         return gensec_krb5_common_client_start(gensec_security, false);
 396 }
 397
 398 static NTSTATUS gensec_fake_gssapi_krb5_client_start(struct gensec_security *gensec_security)
 399 {
 400         return gensec_krb5_common_client_start(gensec_security, true);
 401 }
 402
 403
 404 /*
 405   generate a krb5 GSS-API wrapper packet given a ticket
 406 */
 407 static DATA_BLOB gensec_gssapi_gen_krb5_wrap(TALLOC_CTX *mem_ctx, const DATA_BLOB *ticket, const uint8_t tok_id[2])
 408 {
 409         struct asn1_data *data;
 410         DATA_BLOB ret = data_blob_null;
 411
 412         data = asn1_init(mem_ctx);
 413         if (!data || !ticket->data) {
 414                 return ret;
 415         }
 416
 417         if (!asn1_push_tag(data, ASN1_APPLICATION(0))) goto err;
 418         if (!asn1_write_OID(data, GENSEC_OID_KERBEROS5)) goto err;
 419
 420         if (!asn1_write(data, tok_id, 2)) goto err;
 421         if (!asn1_write(data, ticket->data, ticket->length)) goto err;
 422         if (!asn1_pop_tag(data)) goto err;
 423
 424
 425         if (!asn1_extract_blob(data, mem_ctx, &ret)) {
 426                 goto err;
 427         }
 428         asn1_free(data);
 429
 430         return ret;
 431
 432   err:
 433
 434         DEBUG(1, ("Failed to build krb5 wrapper at offset %d\n",
 435                   (int)asn1_current_ofs(data)));
 436         asn1_free(data);
 437         return ret;
 438 }
 439
 440 /*
 441   parse a krb5 GSS-API wrapper packet giving a ticket
 442 */
 443 static bool gensec_gssapi_parse_krb5_wrap(TALLOC_CTX *mem_ctx, const DATA_BLOB *blob, DATA_BLOB *ticket, uint8_t tok_id[2])
 444 {
 445         bool ret = false;
 446         struct asn1_data *data = asn1_init(mem_ctx);
 447         int data_remaining;
 448
 449         if (!data) {
 450                 return false;
 451         }
 452
 453         if (!asn1_load(data, *blob)) goto err;
 454         if (!asn1_start_tag(data, ASN1_APPLICATION(0))) goto err;
 455         if (!asn1_check_OID(data, GENSEC_OID_KERBEROS5)) goto err;
 456
 457         data_remaining = asn1_tag_remaining(data);
 458
 459         if (data_remaining < 3) {
 460                 asn1_set_error(data);
 461         } else {
 462                 if (!asn1_read(data, tok_id, 2)) goto err;
 463                 data_remaining -= 2;
 464                 *ticket = data_blob_talloc(mem_ctx, NULL, data_remaining);
 465                 if (!asn1_read(data, ticket->data, ticket->length)) goto err;
 466         }
 467
 468         if (!asn1_end_tag(data)) goto err;
 469
 470         ret = !asn1_has_error(data);
 471
 472   err:
 473
 474         asn1_free(data);
 475
 476         return ret;
 477 }
 478
 479 /**
 480  * Next state function for the Krb5 GENSEC mechanism
 481  *
 482  * @param gensec_krb5_state KRB5 State
 483  * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
 484  * @param in The request, as a DATA_BLOB
 485  * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
 486  * @return Error, MORE_PROCESSING_REQUIRED if a reply is sent,
 487  *                or NT_STATUS_OK if the user is authenticated.
 488  */
 489
 490 static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 491                                    TALLOC_CTX *out_mem_ctx,
 492                                    struct tevent_context *ev,
 493                                    const DATA_BLOB in, DATA_BLOB *out)
 494 {
 495         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 496         krb5_error_code ret = 0;
 497         NTSTATUS nt_status;
 498
 499         switch (gensec_krb5_state->state_position) {
 500         case GENSEC_KRB5_CLIENT_START:
 501         {
 502                 DATA_BLOB unwrapped_out;
 503
 504                 nt_status = gensec_krb5_common_client_creds(gensec_security, ev, gensec_krb5_state->gssapi);
 505                 if (!NT_STATUS_IS_OK(nt_status)) {
 506                         return nt_status;
 507                 }
 508
 509                 if (gensec_krb5_state->gssapi) {
 510                         unwrapped_out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 511
 512                         /* wrap that up in a nice GSS-API wrapping */
 513                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REQ);
 514                 } else {
 515                         *out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 516                 }
 517                 if (gensec_krb5_state->ap_req_options & AP_OPTS_MUTUAL_REQUIRED) {
 518                         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_MUTUAL_AUTH;
 519                         nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
 520                 } else {
 521                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 522                         nt_status = NT_STATUS_OK;
 523                 }
 524                 return nt_status;
 525         }
 526
 527         case GENSEC_KRB5_CLIENT_MUTUAL_AUTH:
 528         {
 529                 DATA_BLOB unwrapped_in;
 530                 krb5_data inbuf;
 531                 krb5_ap_rep_enc_part *repl = NULL;
 532                 uint8_t tok_id[2];
 533
 534                 if (gensec_krb5_state->gssapi) {
 535                         if (!gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 536                                 DEBUG(1,("gensec_gssapi_parse_krb5_wrap(mutual authentication) failed to parse\n"));
 537                                 dump_data_pw("Mutual authentication message:\n", in.data, in.length);
 538                                 return NT_STATUS_INVALID_PARAMETER;
 539                         }
 540                 } else {
 541                         unwrapped_in = in;
 542                 }
 543                 /* TODO: check the tok_id */
 544
 545                 inbuf.data = unwrapped_in.data;
 546                 inbuf.length = unwrapped_in.length;
 547                 ret = krb5_rd_rep(gensec_krb5_state->smb_krb5_context->krb5_context,
 548                                   gensec_krb5_state->auth_context,
 549                                   &inbuf, &repl);
 550                 if (ret) {
 551                         DEBUG(1,("krb5_rd_rep (mutual authentication) failed (%s)\n",
 552                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, out_mem_ctx)));
 553                         dump_data_pw("Mutual authentication message:\n", (uint8_t *)inbuf.data, inbuf.length);
 554                         nt_status = NT_STATUS_ACCESS_DENIED;
 555                 } else {
 556                         *out = data_blob(NULL, 0);
 557                         nt_status = NT_STATUS_OK;
 558                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 559                 }
 560                 if (repl) {
 561                         krb5_free_ap_rep_enc_part(gensec_krb5_state->smb_krb5_context->krb5_context, repl);
 562                 }
 563                 return nt_status;
 564         }
 565
 566         case GENSEC_KRB5_SERVER_START:
 567         {
 568                 DATA_BLOB unwrapped_in;
 569                 DATA_BLOB unwrapped_out = data_blob(NULL, 0);
 570                 krb5_data inbuf, outbuf;
 571                 uint8_t tok_id[2];
 572                 struct keytab_container *keytab;
 573                 krb5_principal server_in_keytab;
 574                 const char *error_string;
 575                 enum credentials_obtained obtained;
 576
 577                 if (!in.data) {
 578                         return NT_STATUS_INVALID_PARAMETER;
 579                 }
 580
 581                 /* Grab the keytab, however generated */
 582                 ret = cli_credentials_get_keytab(gensec_get_credentials(gensec_security),
 583                                                  gensec_security->settings->lp_ctx, &keytab);
 584                 if (ret) {
 585                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 586                 }
 587
 588                 /* This ensures we lookup the correct entry in that
 589                  * keytab.  A NULL principal is acceptable, and means
 590                  * that the krb5 libs should search the keytab at
 591                  * accept time for any matching key */
 592                 ret = principal_from_credentials(out_mem_ctx, gensec_get_credentials(gensec_security),
 593                                                  gensec_krb5_state->smb_krb5_context,
 594                                                  &server_in_keytab, &obtained, &error_string);
 595
 596                 if (ret) {
 597                         DEBUG(2,("Failed to make credentials from principal: %s\n", error_string));
 598                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 599                 }
 600
 601                 if (keytab->password_based || obtained < CRED_SPECIFIED) {
 602                         /*
 603                          * Use match-by-key in this case (matches
 604                          * cli_credentials_get_server_gss_creds()
 605                          * behaviour).  No need to free the memory,
 606                          * this is handled with a talloc destructor.
 607                          */
 608                         server_in_keytab = NULL;
 609                 }
 610
 611                 /* Parse the GSSAPI wrapping, if it's there... (win2k3 allows it to be omited) */
 612                 if (gensec_krb5_state->gssapi
 613                     && gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 614                         inbuf.data = unwrapped_in.data;
 615                         inbuf.length = unwrapped_in.length;
 616                 } else {
 617                         inbuf.data = in.data;
 618                         inbuf.length = in.length;
 619                 }
 620
 621                 ret = smb_rd_req_return_stuff(gensec_krb5_state->smb_krb5_context->krb5_context,
 622                                               &gensec_krb5_state->auth_context,
 623                                               &inbuf, keytab->keytab, server_in_keytab,
 624                                               &outbuf,
 625                                               &gensec_krb5_state->ticket,
 626                                               &gensec_krb5_state->keyblock);
 627
 628                 if (ret) {
 629                         return NT_STATUS_LOGON_FAILURE;
 630                 }
 631                 unwrapped_out.data = (uint8_t *)outbuf.data;
 632                 unwrapped_out.length = outbuf.length;
 633                 gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 634                 /* wrap that up in a nice GSS-API wrapping */
 635                 if (gensec_krb5_state->gssapi) {
 636                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REP);
 637                 } else {
 638                         *out = data_blob_talloc(out_mem_ctx, outbuf.data, outbuf.length);
 639                 }
 640                 krb5_data_free(&outbuf);
 641                 return NT_STATUS_OK;
 642         }
 643
 644         case GENSEC_KRB5_DONE:
 645         default:
 646                 /* Asking too many times... */
 647                 return NT_STATUS_INVALID_PARAMETER;
 648         }
 649 }
 650
 651 static NTSTATUS gensec_krb5_session_key(struct gensec_security *gensec_security,
 652                                         TALLOC_CTX *mem_ctx,
 653                                         DATA_BLOB *session_key)
 654 {
 655         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 656         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 657         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 658         krb5_keyblock *skey;
 659         krb5_error_code err = -1;
 660
 661         if (gensec_krb5_state->state_position != GENSEC_KRB5_DONE) {
 662                 return NT_STATUS_NO_USER_SESSION_KEY;
 663         }
 664
 665         switch (gensec_security->gensec_role) {
 666         case GENSEC_CLIENT:
 667                 err = krb5_auth_con_getlocalsubkey(context, auth_context, &skey);
 668                 break;
 669         case GENSEC_SERVER:
 670                 err = krb5_auth_con_getremotesubkey(context, auth_context, &skey);
 671                 break;
 672         }
 673         if (err == 0 && skey != NULL) {
 674                 DEBUG(10, ("Got KRB5 session key of length %d\n",
 675                            (int)KRB5_KEY_LENGTH(skey)));
 676                 *session_key = data_blob_talloc(mem_ctx,
 677                                                KRB5_KEY_DATA(skey), KRB5_KEY_LENGTH(skey));
 678                 dump_data_pw("KRB5 Session Key:\n", session_key->data, session_key->length);
 679
 680                 krb5_free_keyblock(context, skey);
 681                 return NT_STATUS_OK;
 682         } else {
 683                 DEBUG(10, ("KRB5 error getting session key %d\n", err));
 684                 return NT_STATUS_NO_USER_SESSION_KEY;
 685         }
 686 }
 687
 688 static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security,
 689                                          TALLOC_CTX *mem_ctx,
 690                                          struct auth_session_info **_session_info)
 691 {
 692         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 693         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 694         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 695         struct auth_session_info *session_info = NULL;
 696
 697         krb5_principal client_principal;
 698         char *principal_string;
 699
 700         DATA_BLOB pac_blob, *pac_blob_ptr = NULL;
 701         krb5_data pac_data;
 702
 703         krb5_error_code ret;
 704
 705         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 706         if (!tmp_ctx) {
 707                 return NT_STATUS_NO_MEMORY;
 708         }
 709
 710         ret = krb5_ticket_get_client(context, gensec_krb5_state->ticket, &client_principal);
 711         if (ret) {
 712                 DEBUG(5, ("krb5_ticket_get_client failed to get cleint principal: %s\n",
 713                           smb_get_krb5_error_message(context,
 714                                                      ret, tmp_ctx)));
 715                 talloc_free(tmp_ctx);
 716                 return NT_STATUS_NO_MEMORY;
 717         }
 718
 719         ret = krb5_unparse_name(gensec_krb5_state->smb_krb5_context->krb5_context,
 720                                 client_principal, &principal_string);
 721         if (ret) {
 722                 DEBUG(1, ("Unable to parse client principal: %s\n",
 723                           smb_get_krb5_error_message(context,
 724                                                      ret, tmp_ctx)));
 725                 krb5_free_principal(context, client_principal);
 726                 talloc_free(tmp_ctx);
 727                 return NT_STATUS_NO_MEMORY;
 728         }
 729
 730         ret = krb5_ticket_get_authorization_data_type(context, gensec_krb5_state->ticket,
 731                                                       KRB5_AUTHDATA_WIN2K_PAC,
 732                                                       &pac_data);
 733
 734         if (ret) {
 735                 /* NO pac */
 736                 DEBUG(5, ("krb5_ticket_get_authorization_data_type failed to find PAC: %s\n",
 737                           smb_get_krb5_error_message(context,
 738                                                      ret, tmp_ctx)));
 739         } else {
 740                 /* Found pac */
 741                 pac_blob = data_blob_talloc(tmp_ctx, pac_data.data, pac_data.length);
 742                 kerberos_free_data_contents(context, &pac_data);
 743                 if (!pac_blob.data) {
 744                         free(principal_string);
 745                         krb5_free_principal(context, client_principal);
 746                         talloc_free(tmp_ctx);
 747                         return NT_STATUS_NO_MEMORY;
 748                 }
 749
 750                 /* decode and verify the pac */
 751                 nt_status = kerberos_decode_pac(gensec_krb5_state,
 752                                                 pac_blob,
 753                                                 gensec_krb5_state->smb_krb5_context->krb5_context,
 754                                                 NULL, gensec_krb5_state->keyblock,
 755                                                 client_principal,
 756                                                 gensec_krb5_state->ticket->ticket.authtime, NULL);
 757
 758                 if (!NT_STATUS_IS_OK(nt_status)) {
 759                         free(principal_string);
 760                         krb5_free_principal(context, client_principal);
 761                         talloc_free(tmp_ctx);
 762                         return nt_status;
 763                 }
 764
 765                 pac_blob_ptr = &pac_blob;
 766         }
 767
 768         nt_status = gensec_generate_session_info_pac(tmp_ctx,
 769                                                      gensec_security,
 770                                                      gensec_krb5_state->smb_krb5_context,
 771                                                      pac_blob_ptr, principal_string,
 772                                                      gensec_get_remote_address(gensec_security),
 773                                                      &session_info);
 774
 775         free(principal_string);
 776         krb5_free_principal(context, client_principal);
 777
 778         if (!NT_STATUS_IS_OK(nt_status)) {
 779                 talloc_free(tmp_ctx);
 780                 return nt_status;
 781         }
 782
 783         nt_status = gensec_krb5_session_key(gensec_security, session_info, &session_info->session_key);
 784
 785         if (!NT_STATUS_IS_OK(nt_status)) {
 786                 talloc_free(tmp_ctx);
 787                 return nt_status;
 788         }
 789
 790         *_session_info = talloc_steal(mem_ctx, session_info);
 791
 792         talloc_free(tmp_ctx);
 793         return NT_STATUS_OK;
 794 }
 795
 796 static NTSTATUS gensec_krb5_wrap(struct gensec_security *gensec_security,
 797                                    TALLOC_CTX *mem_ctx,
 798                                    const DATA_BLOB *in,
 799                                    DATA_BLOB *out)
 800 {
 801         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 802         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 803         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 804         krb5_error_code ret;
 805         krb5_data input, output;
 806         input.length = in->length;
 807         input.data = in->data;
 808
 809         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 810                 ret = krb5_mk_priv(context, auth_context, &input, &output, NULL);
 811                 if (ret) {
 812                         DEBUG(1, ("krb5_mk_priv failed: %s\n",
 813                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 814                                                              ret, mem_ctx)));
 815                         return NT_STATUS_ACCESS_DENIED;
 816                 }
 817                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 818
 819                 krb5_data_free(&output);
 820         } else {
 821                 return NT_STATUS_ACCESS_DENIED;
 822         }
 823         return NT_STATUS_OK;
 824 }
 825
 826 static NTSTATUS gensec_krb5_unwrap(struct gensec_security *gensec_security,
 827                                      TALLOC_CTX *mem_ctx,
 828                                      const DATA_BLOB *in,
 829                                      DATA_BLOB *out)
 830 {
 831         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 832         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 833         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 834         krb5_error_code ret;
 835         krb5_data input, output;
 836         krb5_replay_data replay;
 837         input.length = in->length;
 838         input.data = in->data;
 839
 840         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 841                 ret = krb5_rd_priv(context, auth_context, &input, &output, &replay);
 842                 if (ret) {
 843                         DEBUG(1, ("krb5_rd_priv failed: %s\n",
 844                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 845                                                              ret, mem_ctx)));
 846                         return NT_STATUS_ACCESS_DENIED;
 847                 }
 848                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 849
 850                 krb5_data_free(&output);
 851         } else {
 852                 return NT_STATUS_ACCESS_DENIED;
 853         }
 854         return NT_STATUS_OK;
 855 }
 856
 857 static bool gensec_krb5_have_feature(struct gensec_security *gensec_security,
 858                                      uint32_t feature)
 859 {
 860         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 861         if (feature & GENSEC_FEATURE_SESSION_KEY) {
 862                 return true;
 863         }
 864         if (!gensec_krb5_state->gssapi &&
 865             (feature & GENSEC_FEATURE_SEAL)) {
 866                 return true;
 867         }
 868
 869         return false;
 870 }
 871
 872 static const char *gensec_krb5_oids[] = {
 873         GENSEC_OID_KERBEROS5,
 874         GENSEC_OID_KERBEROS5_OLD,
 875         NULL
 876 };
 877
 878 static const struct gensec_security_ops gensec_fake_gssapi_krb5_security_ops = {
 879         .name           = "fake_gssapi_krb5",
 880         .auth_type      = DCERPC_AUTH_TYPE_KRB5,
 881         .oid            = gensec_krb5_oids,
 882         .client_start   = gensec_fake_gssapi_krb5_client_start,
 883         .server_start   = gensec_fake_gssapi_krb5_server_start,
 884         .update         = gensec_krb5_update,
 885         .magic          = gensec_magic_check_krb5_oid,
 886         .session_key    = gensec_krb5_session_key,
 887         .session_info   = gensec_krb5_session_info,
 888         .have_feature   = gensec_krb5_have_feature,
 889         .enabled        = false,
 890         .kerberos       = true,
 891         .priority       = GENSEC_KRB5
 892 };
 893
 894 static const struct gensec_security_ops gensec_krb5_security_ops = {
 895         .name           = "krb5",
 896         .client_start   = gensec_krb5_client_start,
 897         .server_start   = gensec_krb5_server_start,
 898         .update         = gensec_krb5_update,
 899         .session_key    = gensec_krb5_session_key,
 900         .session_info   = gensec_krb5_session_info,
 901         .have_feature   = gensec_krb5_have_feature,
 902         .wrap           = gensec_krb5_wrap,
 903         .unwrap         = gensec_krb5_unwrap,
 904         .enabled        = true,
 905         .kerberos       = true,
 906         .priority       = GENSEC_KRB5
 907 };
 908
 909 _PUBLIC_ NTSTATUS gensec_krb5_init(void)
 910 {
 911         NTSTATUS ret;
 912
 913         ret = gensec_register(&gensec_krb5_security_ops);
 914         if (!NT_STATUS_IS_OK(ret)) {
 915                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 916                         gensec_krb5_security_ops.name));
 917                 return ret;
 918         }
 919
 920         ret = gensec_register(&gensec_fake_gssapi_krb5_security_ops);
 921         if (!NT_STATUS_IS_OK(ret)) {
 922                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 923                         gensec_fake_gssapi_krb5_security_ops.name));
 924                 return ret;
 925         }
 926
 927         return ret;
 928 }