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