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