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