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