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 "param/param.h"
  39 #include "auth/auth_sam_reply.h"
  40 #include "lib/util/util_net.h"
  41
  42 _PUBLIC_ NTSTATUS gensec_krb5_init(void);
  43
  44 enum GENSEC_KRB5_STATE {
  45         GENSEC_KRB5_SERVER_START,
  46         GENSEC_KRB5_CLIENT_START,
  47         GENSEC_KRB5_CLIENT_MUTUAL_AUTH,
  48         GENSEC_KRB5_DONE
  49 };
  50
  51 struct gensec_krb5_state {
  52         DATA_BLOB session_key;
  53         DATA_BLOB pac;
  54         enum GENSEC_KRB5_STATE state_position;
  55         struct smb_krb5_context *smb_krb5_context;
  56         krb5_auth_context auth_context;
  57         krb5_data enc_ticket;
  58         krb5_keyblock *keyblock;
  59         krb5_ticket *ticket;
  60         bool gssapi;
  61         krb5_flags ap_req_options;
  62 };
  63
  64 static int gensec_krb5_destroy(struct gensec_krb5_state *gensec_krb5_state)
  65 {
  66         if (!gensec_krb5_state->smb_krb5_context) {
  67                 /* We can't clean anything else up unless we started up this far */
  68                 return 0;
  69         }
  70         if (gensec_krb5_state->enc_ticket.length) {
  71                 kerberos_free_data_contents(gensec_krb5_state->smb_krb5_context->krb5_context,
  72                                             &gensec_krb5_state->enc_ticket);
  73         }
  74
  75         if (gensec_krb5_state->ticket) {
  76                 krb5_free_ticket(gensec_krb5_state->smb_krb5_context->krb5_context,
  77                                  gensec_krb5_state->ticket);
  78         }
  79
  80         /* ccache freed in a child destructor */
  81
  82         krb5_free_keyblock(gensec_krb5_state->smb_krb5_context->krb5_context,
  83                            gensec_krb5_state->keyblock);
  84
  85         if (gensec_krb5_state->auth_context) {
  86                 krb5_auth_con_free(gensec_krb5_state->smb_krb5_context->krb5_context,
  87                                    gensec_krb5_state->auth_context);
  88         }
  89
  90         return 0;
  91 }
  92
  93 static NTSTATUS gensec_krb5_start(struct gensec_security *gensec_security, bool gssapi)
  94 {
  95         krb5_error_code ret;
  96         struct gensec_krb5_state *gensec_krb5_state;
  97         struct cli_credentials *creds;
  98         const struct tsocket_address *tlocal_addr, *tremote_addr;
  99         krb5_address my_krb5_addr, peer_krb5_addr;
 100
 101         creds = gensec_get_credentials(gensec_security);
 102         if (!creds) {
 103                 return NT_STATUS_INVALID_PARAMETER;
 104         }
 105
 106         gensec_krb5_state = talloc(gensec_security, struct gensec_krb5_state);
 107         if (!gensec_krb5_state) {
 108                 return NT_STATUS_NO_MEMORY;
 109         }
 110
 111         gensec_security->private_data = gensec_krb5_state;
 112         gensec_krb5_state->smb_krb5_context = NULL;
 113         gensec_krb5_state->auth_context = NULL;
 114         gensec_krb5_state->ticket = NULL;
 115         ZERO_STRUCT(gensec_krb5_state->enc_ticket);
 116         gensec_krb5_state->keyblock = NULL;
 117         gensec_krb5_state->session_key = data_blob(NULL, 0);
 118         gensec_krb5_state->pac = data_blob(NULL, 0);
 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         struct gensec_krb5_state *gensec_krb5_state;
 239         krb5_error_code ret;
 240         NTSTATUS nt_status;
 241         struct ccache_container *ccache_container;
 242         const char *hostname;
 243         const char *error_string;
 244         const char *principal;
 245         krb5_data in_data;
 246         struct tevent_context *previous_ev;
 247
 248         hostname = gensec_get_target_hostname(gensec_security);
 249         if (!hostname) {
 250                 DEBUG(1, ("Could not determine hostname for target computer, cannot use kerberos\n"));
 251                 return NT_STATUS_INVALID_PARAMETER;
 252         }
 253         if (is_ipaddress(hostname)) {
 254                 DEBUG(2, ("Cannot do krb5 to an IP address"));
 255                 return NT_STATUS_INVALID_PARAMETER;
 256         }
 257         if (strcmp(hostname, "localhost") == 0) {
 258                 DEBUG(2, ("krb5 to 'localhost' does not make sense"));
 259                 return NT_STATUS_INVALID_PARAMETER;
 260         }
 261
 262         nt_status = gensec_krb5_start(gensec_security, gssapi);
 263         if (!NT_STATUS_IS_OK(nt_status)) {
 264                 return nt_status;
 265         }
 266
 267         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 268         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_START;
 269         gensec_krb5_state->ap_req_options = AP_OPTS_USE_SUBKEY;
 270
 271         if (gensec_krb5_state->gssapi) {
 272                 /* The Fake GSSAPI modal emulates Samba3, which does not do mutual authentication */
 273                 if (gensec_setting_bool(gensec_security->settings, "gensec_fake_gssapi_krb5", "mutual", false)) {
 274                         gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 275                 }
 276         } else {
 277                 /* The wrapping for KPASSWD (a user of the raw KRB5 API) should be mutually authenticated */
 278                 if (gensec_setting_bool(gensec_security->settings, "gensec_krb5", "mutual", true)) {
 279                         gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 280                 }
 281         }
 282
 283         principal = gensec_get_target_principal(gensec_security);
 284
 285         ret = cli_credentials_get_ccache(gensec_get_credentials(gensec_security),
 286                                          gensec_security->event_ctx,
 287                                          gensec_security->settings->lp_ctx, &ccache_container, &error_string);
 288         switch (ret) {
 289         case 0:
 290                 break;
 291         case KRB5KDC_ERR_PREAUTH_FAILED:
 292         case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
 293                 return NT_STATUS_LOGON_FAILURE;
 294         case KRB5_KDC_UNREACH:
 295                 DEBUG(3, ("Cannot reach a KDC we require to contact %s: %s\n", principal, error_string));
 296                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 297         case KRB5_CC_NOTFOUND:
 298         case KRB5_CC_END:
 299                 DEBUG(3, ("Error preparing credentials we require to contact %s : %s\n", principal, error_string));
 300                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 301         default:
 302                 DEBUG(1, ("gensec_krb5_start: Aquiring initiator credentials failed: %s\n", error_string));
 303                 return NT_STATUS_UNSUCCESSFUL;
 304         }
 305         in_data.length = 0;
 306
 307         /* Do this every time, in case we have weird recursive issues here */
 308         ret = smb_krb5_context_set_event_ctx(gensec_krb5_state->smb_krb5_context, gensec_security->event_ctx, &previous_ev);
 309         if (ret != 0) {
 310                 DEBUG(1, ("gensec_krb5_start: Setting event context failed\n"));
 311                 return NT_STATUS_NO_MEMORY;
 312         }
 313         if (principal) {
 314                 krb5_principal target_principal;
 315                 ret = krb5_parse_name(gensec_krb5_state->smb_krb5_context->krb5_context, principal,
 316                                       &target_principal);
 317                 if (ret == 0) {
 318                         ret = krb5_mk_req_exact(gensec_krb5_state->smb_krb5_context->krb5_context,
 319                                                 &gensec_krb5_state->auth_context,
 320                                                 gensec_krb5_state->ap_req_options,
 321                                                 target_principal,
 322                                                 &in_data, ccache_container->ccache,
 323                                                 &gensec_krb5_state->enc_ticket);
 324                         krb5_free_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
 325                                             target_principal);
 326                 }
 327         } else {
 328                 ret = krb5_mk_req(gensec_krb5_state->smb_krb5_context->krb5_context,
 329                                   &gensec_krb5_state->auth_context,
 330                                   gensec_krb5_state->ap_req_options,
 331                                   gensec_get_target_service(gensec_security),
 332                                   hostname,
 333                                   &in_data, ccache_container->ccache,
 334                                   &gensec_krb5_state->enc_ticket);
 335         }
 336
 337         smb_krb5_context_remove_event_ctx(gensec_krb5_state->smb_krb5_context, previous_ev, gensec_security->event_ctx);
 338
 339         switch (ret) {
 340         case 0:
 341                 return NT_STATUS_OK;
 342         case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
 343                 DEBUG(3, ("Server [%s] is not registered with our KDC: %s\n",
 344                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 345                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 346         case KRB5_KDC_UNREACH:
 347                 DEBUG(3, ("Cannot reach a KDC we require to contact host [%s]: %s\n",
 348                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 349                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 350         case KRB5KDC_ERR_PREAUTH_FAILED:
 351         case KRB5KRB_AP_ERR_TKT_EXPIRED:
 352         case KRB5_CC_END:
 353                 /* Too much clock skew - we will need to kinit to re-skew the clock */
 354         case KRB5KRB_AP_ERR_SKEW:
 355         case KRB5_KDCREP_SKEW:
 356         {
 357                 DEBUG(3, ("kerberos (mk_req) failed: %s\n",
 358                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 359                 /*fall through*/
 360         }
 361
 362         /* just don't print a message for these really ordinary messages */
 363         case KRB5_FCC_NOFILE:
 364         case KRB5_CC_NOTFOUND:
 365         case ENOENT:
 366
 367                 return NT_STATUS_UNSUCCESSFUL;
 368                 break;
 369
 370         default:
 371                 DEBUG(0, ("kerberos: %s\n",
 372                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 373                 return NT_STATUS_UNSUCCESSFUL;
 374         }
 375 }
 376
 377 static NTSTATUS gensec_krb5_client_start(struct gensec_security *gensec_security)
 378 {
 379         return gensec_krb5_common_client_start(gensec_security, false);
 380 }
 381
 382 static NTSTATUS gensec_fake_gssapi_krb5_client_start(struct gensec_security *gensec_security)
 383 {
 384         return gensec_krb5_common_client_start(gensec_security, true);
 385 }
 386
 387 /**
 388  * Check if the packet is one for this mechansim
 389  *
 390  * @param gensec_security GENSEC state
 391  * @param in The request, as a DATA_BLOB
 392  * @return Error, INVALID_PARAMETER if it's not a packet for us
 393  *                or NT_STATUS_OK if the packet is ok.
 394  */
 395
 396 static NTSTATUS gensec_fake_gssapi_krb5_magic(struct gensec_security *gensec_security,
 397                                   const DATA_BLOB *in)
 398 {
 399         if (gensec_gssapi_check_oid(in, GENSEC_OID_KERBEROS5)) {
 400                 return NT_STATUS_OK;
 401         } else {
 402                 return NT_STATUS_INVALID_PARAMETER;
 403         }
 404 }
 405
 406
 407 /**
 408  * Next state function for the Krb5 GENSEC mechanism
 409  *
 410  * @param gensec_krb5_state KRB5 State
 411  * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
 412  * @param in The request, as a DATA_BLOB
 413  * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
 414  * @return Error, MORE_PROCESSING_REQUIRED if a reply is sent,
 415  *                or NT_STATUS_OK if the user is authenticated.
 416  */
 417
 418 static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 419                                    TALLOC_CTX *out_mem_ctx,
 420                                    const DATA_BLOB in, DATA_BLOB *out)
 421 {
 422         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 423         krb5_error_code ret = 0;
 424         NTSTATUS nt_status;
 425
 426         switch (gensec_krb5_state->state_position) {
 427         case GENSEC_KRB5_CLIENT_START:
 428         {
 429                 DATA_BLOB unwrapped_out;
 430
 431                 if (gensec_krb5_state->gssapi) {
 432                         unwrapped_out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 433
 434                         /* wrap that up in a nice GSS-API wrapping */
 435                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REQ);
 436                 } else {
 437                         *out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 438                 }
 439                 if (gensec_krb5_state->ap_req_options & AP_OPTS_MUTUAL_REQUIRED) {
 440                         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_MUTUAL_AUTH;
 441                         nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
 442                 } else {
 443                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 444                         nt_status = NT_STATUS_OK;
 445                 }
 446                 return nt_status;
 447         }
 448
 449         case GENSEC_KRB5_CLIENT_MUTUAL_AUTH:
 450         {
 451                 DATA_BLOB unwrapped_in;
 452                 krb5_data inbuf;
 453                 krb5_ap_rep_enc_part *repl = NULL;
 454                 uint8_t tok_id[2];
 455
 456                 if (gensec_krb5_state->gssapi) {
 457                         if (!gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 458                                 DEBUG(1,("gensec_gssapi_parse_krb5_wrap(mutual authentication) failed to parse\n"));
 459                                 dump_data_pw("Mutual authentication message:\n", in.data, in.length);
 460                                 return NT_STATUS_INVALID_PARAMETER;
 461                         }
 462                 } else {
 463                         unwrapped_in = in;
 464                 }
 465                 /* TODO: check the tok_id */
 466
 467                 inbuf.data = unwrapped_in.data;
 468                 inbuf.length = unwrapped_in.length;
 469                 ret = krb5_rd_rep(gensec_krb5_state->smb_krb5_context->krb5_context,
 470                                   gensec_krb5_state->auth_context,
 471                                   &inbuf, &repl);
 472                 if (ret) {
 473                         DEBUG(1,("krb5_rd_rep (mutual authentication) failed (%s)\n",
 474                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, out_mem_ctx)));
 475                         dump_data_pw("Mutual authentication message:\n", (uint8_t *)inbuf.data, inbuf.length);
 476                         nt_status = NT_STATUS_ACCESS_DENIED;
 477                 } else {
 478                         *out = data_blob(NULL, 0);
 479                         nt_status = NT_STATUS_OK;
 480                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 481                 }
 482                 if (repl) {
 483                         krb5_free_ap_rep_enc_part(gensec_krb5_state->smb_krb5_context->krb5_context, repl);
 484                 }
 485                 return nt_status;
 486         }
 487
 488         case GENSEC_KRB5_SERVER_START:
 489         {
 490                 DATA_BLOB unwrapped_in;
 491                 DATA_BLOB unwrapped_out = data_blob(NULL, 0);
 492                 krb5_data inbuf, outbuf;
 493                 uint8_t tok_id[2];
 494                 struct keytab_container *keytab;
 495                 krb5_principal server_in_keytab;
 496                 const char *error_string;
 497                 enum credentials_obtained obtained;
 498
 499                 if (!in.data) {
 500                         return NT_STATUS_INVALID_PARAMETER;
 501                 }
 502
 503                 /* Grab the keytab, however generated */
 504                 ret = cli_credentials_get_keytab(gensec_get_credentials(gensec_security),
 505                                                  gensec_security->settings->lp_ctx, &keytab);
 506                 if (ret) {
 507                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 508                 }
 509
 510                 /* This ensures we lookup the correct entry in that keytab */
 511                 ret = principal_from_credentials(out_mem_ctx, gensec_get_credentials(gensec_security),
 512                                                  gensec_krb5_state->smb_krb5_context,
 513                                                  &server_in_keytab, &obtained, &error_string);
 514
 515                 if (ret) {
 516                         DEBUG(2,("Failed to make credentials from principal: %s\n", error_string));
 517                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 518                 }
 519
 520                 /* Parse the GSSAPI wrapping, if it's there... (win2k3 allows it to be omited) */
 521                 if (gensec_krb5_state->gssapi
 522                     && gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 523                         inbuf.data = unwrapped_in.data;
 524                         inbuf.length = unwrapped_in.length;
 525                 } else {
 526                         inbuf.data = in.data;
 527                         inbuf.length = in.length;
 528                 }
 529
 530                 ret = smb_rd_req_return_stuff(gensec_krb5_state->smb_krb5_context->krb5_context,
 531                                               &gensec_krb5_state->auth_context,
 532                                               &inbuf, keytab->keytab, server_in_keytab,
 533                                               &outbuf,
 534                                               &gensec_krb5_state->ticket,
 535                                               &gensec_krb5_state->keyblock);
 536
 537                 if (ret) {
 538                         return NT_STATUS_LOGON_FAILURE;
 539                 }
 540                 unwrapped_out.data = (uint8_t *)outbuf.data;
 541                 unwrapped_out.length = outbuf.length;
 542                 gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 543                 /* wrap that up in a nice GSS-API wrapping */
 544                 if (gensec_krb5_state->gssapi) {
 545                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REP);
 546                 } else {
 547                         *out = data_blob_talloc(out_mem_ctx, outbuf.data, outbuf.length);
 548                 }
 549                 krb5_data_free(&outbuf);
 550                 return NT_STATUS_OK;
 551         }
 552
 553         case GENSEC_KRB5_DONE:
 554         default:
 555                 /* Asking too many times... */
 556                 return NT_STATUS_INVALID_PARAMETER;
 557         }
 558 }
 559
 560 static NTSTATUS gensec_krb5_session_key(struct gensec_security *gensec_security,
 561                                         DATA_BLOB *session_key)
 562 {
 563         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 564         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 565         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 566         krb5_keyblock *skey;
 567         krb5_error_code err = -1;
 568
 569         if (gensec_krb5_state->state_position != GENSEC_KRB5_DONE) {
 570                 return NT_STATUS_NO_USER_SESSION_KEY;
 571         }
 572
 573         if (gensec_krb5_state->session_key.data) {
 574                 *session_key = gensec_krb5_state->session_key;
 575                 return NT_STATUS_OK;
 576         }
 577
 578         switch (gensec_security->gensec_role) {
 579         case GENSEC_CLIENT:
 580                 err = krb5_auth_con_getlocalsubkey(context, auth_context, &skey);
 581                 break;
 582         case GENSEC_SERVER:
 583                 err = krb5_auth_con_getremotesubkey(context, auth_context, &skey);
 584                 break;
 585         }
 586         if (err == 0 && skey != NULL) {
 587                 DEBUG(10, ("Got KRB5 session key of length %d\n",
 588                            (int)KRB5_KEY_LENGTH(skey)));
 589                 gensec_krb5_state->session_key = data_blob_talloc(gensec_krb5_state,
 590                                                 KRB5_KEY_DATA(skey), KRB5_KEY_LENGTH(skey));
 591                 *session_key = gensec_krb5_state->session_key;
 592                 dump_data_pw("KRB5 Session Key:\n", session_key->data, session_key->length);
 593
 594                 krb5_free_keyblock(context, skey);
 595                 return NT_STATUS_OK;
 596         } else {
 597                 DEBUG(10, ("KRB5 error getting session key %d\n", err));
 598                 return NT_STATUS_NO_USER_SESSION_KEY;
 599         }
 600 }
 601
 602 static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security,
 603                                          struct auth_session_info **_session_info)
 604 {
 605         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 606         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 607         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 608         struct auth_user_info_dc *user_info_dc = NULL;
 609         struct auth_session_info *session_info = NULL;
 610         struct PAC_LOGON_INFO *logon_info;
 611
 612         krb5_principal client_principal;
 613         char *principal_string;
 614
 615         DATA_BLOB pac;
 616         krb5_data pac_data;
 617
 618         krb5_error_code ret;
 619
 620         TALLOC_CTX *mem_ctx = talloc_new(gensec_security);
 621         if (!mem_ctx) {
 622                 return NT_STATUS_NO_MEMORY;
 623         }
 624
 625         ret = krb5_ticket_get_client(context, gensec_krb5_state->ticket, &client_principal);
 626         if (ret) {
 627                 DEBUG(5, ("krb5_ticket_get_client failed to get cleint principal: %s\n",
 628                           smb_get_krb5_error_message(context,
 629                                                      ret, mem_ctx)));
 630                 talloc_free(mem_ctx);
 631                 return NT_STATUS_NO_MEMORY;
 632         }
 633
 634         ret = krb5_unparse_name(gensec_krb5_state->smb_krb5_context->krb5_context,
 635                                 client_principal, &principal_string);
 636         if (ret) {
 637                 DEBUG(1, ("Unable to parse client principal: %s\n",
 638                           smb_get_krb5_error_message(context,
 639                                                      ret, mem_ctx)));
 640                 krb5_free_principal(context, client_principal);
 641                 talloc_free(mem_ctx);
 642                 return NT_STATUS_NO_MEMORY;
 643         }
 644
 645         ret = krb5_ticket_get_authorization_data_type(context, gensec_krb5_state->ticket,
 646                                                       KRB5_AUTHDATA_WIN2K_PAC,
 647                                                       &pac_data);
 648
 649         if (ret && gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
 650                 DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access: %s \n",
 651                           principal_string,
 652                           smb_get_krb5_error_message(context,
 653                                                      ret, mem_ctx)));
 654                 free(principal_string);
 655                 krb5_free_principal(context, client_principal);
 656                 talloc_free(mem_ctx);
 657                 return NT_STATUS_ACCESS_DENIED;
 658         } else if (ret) {
 659                 /* NO pac */
 660                 DEBUG(5, ("krb5_ticket_get_authorization_data_type failed to find PAC: %s\n",
 661                           smb_get_krb5_error_message(context,
 662                                                      ret, mem_ctx)));
 663                 if (gensec_security->auth_context &&
 664                     !gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
 665                         DEBUG(1, ("Unable to find PAC for %s, resorting to local user lookup: %s",
 666                                   principal_string, smb_get_krb5_error_message(context,
 667                                                      ret, mem_ctx)));
 668                         nt_status = gensec_security->auth_context->get_user_info_dc_principal(mem_ctx,
 669                                                                                              gensec_security->auth_context,
 670                                                                                              principal_string,
 671                                                                                              NULL, &user_info_dc);
 672                         if (!NT_STATUS_IS_OK(nt_status)) {
 673                                 free(principal_string);
 674                                 krb5_free_principal(context, client_principal);
 675                                 talloc_free(mem_ctx);
 676                                 return nt_status;
 677                         }
 678                 } else {
 679                         DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access\n",
 680                                   principal_string));
 681                         free(principal_string);
 682                         krb5_free_principal(context, client_principal);
 683                         talloc_free(mem_ctx);
 684                         return NT_STATUS_ACCESS_DENIED;
 685                 }
 686         } else {
 687                 /* Found pac */
 688                 union netr_Validation validation;
 689
 690                 pac = data_blob_talloc(mem_ctx, pac_data.data, pac_data.length);
 691                 if (!pac.data) {
 692                         free(principal_string);
 693                         krb5_free_principal(context, client_principal);
 694                         talloc_free(mem_ctx);
 695                         return NT_STATUS_NO_MEMORY;
 696                 }
 697
 698                 /* decode and verify the pac */
 699                 nt_status = kerberos_pac_logon_info(gensec_krb5_state,
 700                                                     pac,
 701                                                     gensec_krb5_state->smb_krb5_context->krb5_context,
 702                                                     NULL, gensec_krb5_state->keyblock,
 703                                                     client_principal,
 704                                                     gensec_krb5_state->ticket->ticket.authtime, &logon_info);
 705
 706                 if (!NT_STATUS_IS_OK(nt_status)) {
 707                         free(principal_string);
 708                         krb5_free_principal(context, client_principal);
 709                         talloc_free(mem_ctx);
 710                         return nt_status;
 711                 }
 712
 713                 validation.sam3 = &logon_info->info3;
 714                 nt_status = make_user_info_dc_netlogon_validation(mem_ctx,
 715                                                                  NULL,
 716                                                                  3, &validation,
 717                                                                   true, /* This user was authenticated */
 718                                                                  &user_info_dc);
 719                 if (!NT_STATUS_IS_OK(nt_status)) {
 720                         free(principal_string);
 721                         krb5_free_principal(context, client_principal);
 722                         talloc_free(mem_ctx);
 723                         return nt_status;
 724                 }
 725         }
 726
 727         free(principal_string);
 728         krb5_free_principal(context, client_principal);
 729
 730         /* references the user_info_dc into the session_info */
 731         nt_status = gensec_generate_session_info(mem_ctx, gensec_security, user_info_dc, &session_info);
 732
 733         if (!NT_STATUS_IS_OK(nt_status)) {
 734                 talloc_free(mem_ctx);
 735                 return nt_status;
 736         }
 737
 738         nt_status = gensec_krb5_session_key(gensec_security, &session_info->session_key);
 739
 740         if (!NT_STATUS_IS_OK(nt_status)) {
 741                 talloc_free(mem_ctx);
 742                 return nt_status;
 743         }
 744
 745         *_session_info = session_info;
 746
 747         talloc_steal(gensec_krb5_state, session_info);
 748         talloc_free(mem_ctx);
 749         return NT_STATUS_OK;
 750 }
 751
 752 static NTSTATUS gensec_krb5_wrap(struct gensec_security *gensec_security,
 753                                    TALLOC_CTX *mem_ctx,
 754                                    const DATA_BLOB *in,
 755                                    DATA_BLOB *out)
 756 {
 757         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 758         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 759         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 760         krb5_error_code ret;
 761         krb5_data input, output;
 762         input.length = in->length;
 763         input.data = in->data;
 764
 765         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 766                 ret = krb5_mk_priv(context, auth_context, &input, &output, NULL);
 767                 if (ret) {
 768                         DEBUG(1, ("krb5_mk_priv failed: %s\n",
 769                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 770                                                              ret, mem_ctx)));
 771                         return NT_STATUS_ACCESS_DENIED;
 772                 }
 773                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 774
 775                 krb5_data_free(&output);
 776         } else {
 777                 return NT_STATUS_ACCESS_DENIED;
 778         }
 779         return NT_STATUS_OK;
 780 }
 781
 782 static NTSTATUS gensec_krb5_unwrap(struct gensec_security *gensec_security,
 783                                      TALLOC_CTX *mem_ctx,
 784                                      const DATA_BLOB *in,
 785                                      DATA_BLOB *out)
 786 {
 787         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 788         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 789         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 790         krb5_error_code ret;
 791         krb5_data input, output;
 792         krb5_replay_data replay;
 793         input.length = in->length;
 794         input.data = in->data;
 795
 796         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 797                 ret = krb5_rd_priv(context, auth_context, &input, &output, &replay);
 798                 if (ret) {
 799                         DEBUG(1, ("krb5_rd_priv failed: %s\n",
 800                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 801                                                              ret, mem_ctx)));
 802                         return NT_STATUS_ACCESS_DENIED;
 803                 }
 804                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 805
 806                 krb5_data_free(&output);
 807         } else {
 808                 return NT_STATUS_ACCESS_DENIED;
 809         }
 810         return NT_STATUS_OK;
 811 }
 812
 813 static bool gensec_krb5_have_feature(struct gensec_security *gensec_security,
 814                                      uint32_t feature)
 815 {
 816         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 817         if (feature & GENSEC_FEATURE_SESSION_KEY) {
 818                 return true;
 819         }
 820         if (!gensec_krb5_state->gssapi &&
 821             (feature & GENSEC_FEATURE_SEAL)) {
 822                 return true;
 823         }
 824
 825         return false;
 826 }
 827
 828 static const char *gensec_krb5_oids[] = {
 829         GENSEC_OID_KERBEROS5,
 830         GENSEC_OID_KERBEROS5_OLD,
 831         NULL
 832 };
 833
 834 static const struct gensec_security_ops gensec_fake_gssapi_krb5_security_ops = {
 835         .name           = "fake_gssapi_krb5",
 836         .auth_type      = DCERPC_AUTH_TYPE_KRB5,
 837         .oid            = gensec_krb5_oids,
 838         .client_start   = gensec_fake_gssapi_krb5_client_start,
 839         .server_start   = gensec_fake_gssapi_krb5_server_start,
 840         .update         = gensec_krb5_update,
 841         .magic          = gensec_fake_gssapi_krb5_magic,
 842         .session_key    = gensec_krb5_session_key,
 843         .session_info   = gensec_krb5_session_info,
 844         .have_feature   = gensec_krb5_have_feature,
 845         .enabled        = false,
 846         .kerberos       = true,
 847         .priority       = GENSEC_KRB5
 848 };
 849
 850 static const struct gensec_security_ops gensec_krb5_security_ops = {
 851         .name           = "krb5",
 852         .client_start   = gensec_krb5_client_start,
 853         .server_start   = gensec_krb5_server_start,
 854         .update         = gensec_krb5_update,
 855         .session_key    = gensec_krb5_session_key,
 856         .session_info   = gensec_krb5_session_info,
 857         .have_feature   = gensec_krb5_have_feature,
 858         .wrap           = gensec_krb5_wrap,
 859         .unwrap         = gensec_krb5_unwrap,
 860         .enabled        = true,
 861         .kerberos       = true,
 862         .priority       = GENSEC_KRB5
 863 };
 864
 865 _PUBLIC_ NTSTATUS gensec_krb5_init(void)
 866 {
 867         NTSTATUS ret;
 868
 869         ret = gensec_register(&gensec_krb5_security_ops);
 870         if (!NT_STATUS_IS_OK(ret)) {
 871                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 872                         gensec_krb5_security_ops.name));
 873                 return ret;
 874         }
 875
 876         ret = gensec_register(&gensec_fake_gssapi_krb5_security_ops);
 877         if (!NT_STATUS_IS_OK(ret)) {
 878                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 879                         gensec_krb5_security_ops.name));
 880                 return ret;
 881         }
 882
 883         return ret;
 884 }