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 enum GENSEC_KRB5_STATE {
  43         GENSEC_KRB5_SERVER_START,
  44         GENSEC_KRB5_CLIENT_START,
  45         GENSEC_KRB5_CLIENT_MUTUAL_AUTH,
  46         GENSEC_KRB5_DONE
  47 };
  48
  49 struct gensec_krb5_state {
  50         DATA_BLOB session_key;
  51         DATA_BLOB pac;
  52         enum GENSEC_KRB5_STATE state_position;
  53         struct smb_krb5_context *smb_krb5_context;
  54         krb5_auth_context auth_context;
  55         krb5_data enc_ticket;
  56         krb5_keyblock *keyblock;
  57         krb5_ticket *ticket;
  58         bool gssapi;
  59         krb5_flags ap_req_options;
  60 };
  61
  62 static int gensec_krb5_destroy(struct gensec_krb5_state *gensec_krb5_state)
  63 {
  64         if (!gensec_krb5_state->smb_krb5_context) {
  65                 /* We can't clean anything else up unless we started up this far */
  66                 return 0;
  67         }
  68         if (gensec_krb5_state->enc_ticket.length) {
  69                 kerberos_free_data_contents(gensec_krb5_state->smb_krb5_context->krb5_context,
  70                                             &gensec_krb5_state->enc_ticket);
  71         }
  72
  73         if (gensec_krb5_state->ticket) {
  74                 krb5_free_ticket(gensec_krb5_state->smb_krb5_context->krb5_context,
  75                                  gensec_krb5_state->ticket);
  76         }
  77
  78         /* ccache freed in a child destructor */
  79
  80         krb5_free_keyblock(gensec_krb5_state->smb_krb5_context->krb5_context,
  81                            gensec_krb5_state->keyblock);
  82
  83         if (gensec_krb5_state->auth_context) {
  84                 krb5_auth_con_free(gensec_krb5_state->smb_krb5_context->krb5_context,
  85                                    gensec_krb5_state->auth_context);
  86         }
  87
  88         return 0;
  89 }
  90
  91 static NTSTATUS gensec_krb5_start(struct gensec_security *gensec_security, bool gssapi)
  92 {
  93         krb5_error_code ret;
  94         struct gensec_krb5_state *gensec_krb5_state;
  95         struct cli_credentials *creds;
  96         const struct tsocket_address *tlocal_addr, *tremote_addr;
  97         krb5_address my_krb5_addr, peer_krb5_addr;
  98
  99         creds = gensec_get_credentials(gensec_security);
 100         if (!creds) {
 101                 return NT_STATUS_INVALID_PARAMETER;
 102         }
 103
 104         gensec_krb5_state = talloc(gensec_security, struct gensec_krb5_state);
 105         if (!gensec_krb5_state) {
 106                 return NT_STATUS_NO_MEMORY;
 107         }
 108
 109         gensec_security->private_data = gensec_krb5_state;
 110         gensec_krb5_state->smb_krb5_context = NULL;
 111         gensec_krb5_state->auth_context = NULL;
 112         gensec_krb5_state->ticket = NULL;
 113         ZERO_STRUCT(gensec_krb5_state->enc_ticket);
 114         gensec_krb5_state->keyblock = NULL;
 115         gensec_krb5_state->session_key = data_blob(NULL, 0);
 116         gensec_krb5_state->pac = data_blob(NULL, 0);
 117         gensec_krb5_state->gssapi = gssapi;
 118
 119         talloc_set_destructor(gensec_krb5_state, gensec_krb5_destroy);
 120
 121         if (cli_credentials_get_krb5_context(creds,
 122                                              gensec_security->settings->lp_ctx, &gensec_krb5_state->smb_krb5_context)) {
 123                 talloc_free(gensec_krb5_state);
 124                 return NT_STATUS_INTERNAL_ERROR;
 125         }
 126
 127         ret = krb5_auth_con_init(gensec_krb5_state->smb_krb5_context->krb5_context, &gensec_krb5_state->auth_context);
 128         if (ret) {
 129                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_init failed (%s)\n",
 130                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 131                                                     ret, gensec_krb5_state)));
 132                 talloc_free(gensec_krb5_state);
 133                 return NT_STATUS_INTERNAL_ERROR;
 134         }
 135
 136         ret = krb5_auth_con_setflags(gensec_krb5_state->smb_krb5_context->krb5_context,
 137                                      gensec_krb5_state->auth_context,
 138                                      KRB5_AUTH_CONTEXT_DO_SEQUENCE);
 139         if (ret) {
 140                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_setflags failed (%s)\n",
 141                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 142                                                     ret, gensec_krb5_state)));
 143                 talloc_free(gensec_krb5_state);
 144                 return NT_STATUS_INTERNAL_ERROR;
 145         }
 146
 147         tlocal_addr = gensec_get_local_address(gensec_security);
 148         if (tlocal_addr) {
 149                 ssize_t socklen;
 150                 struct sockaddr_storage ss;
 151
 152                 socklen = tsocket_address_bsd_sockaddr(tlocal_addr,
 153                                 (struct sockaddr *) &ss,
 154                                 sizeof(struct sockaddr_storage));
 155                 if (socklen < 0) {
 156                         talloc_free(gensec_krb5_state);
 157                         return NT_STATUS_INTERNAL_ERROR;
 158                 }
 159                 ret = krb5_sockaddr2address(gensec_krb5_state->smb_krb5_context->krb5_context,
 160                                 (const struct sockaddr *) &ss, &my_krb5_addr);
 161                 if (ret) {
 162                         DEBUG(1,("gensec_krb5_start: krb5_sockaddr2address (local) failed (%s)\n",
 163                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 164                                                             ret, gensec_krb5_state)));
 165                         talloc_free(gensec_krb5_state);
 166                         return NT_STATUS_INTERNAL_ERROR;
 167                 }
 168         }
 169
 170         tremote_addr = gensec_get_remote_address(gensec_security);
 171         if (tremote_addr) {
 172                 ssize_t socklen;
 173                 struct sockaddr_storage ss;
 174
 175                 socklen = tsocket_address_bsd_sockaddr(tremote_addr,
 176                                 (struct sockaddr *) &ss,
 177                                 sizeof(struct sockaddr_storage));
 178                 if (socklen < 0) {
 179                         talloc_free(gensec_krb5_state);
 180                         return NT_STATUS_INTERNAL_ERROR;
 181                 }
 182                 ret = krb5_sockaddr2address(gensec_krb5_state->smb_krb5_context->krb5_context,
 183                                 (const struct sockaddr *) &ss, &peer_krb5_addr);
 184                 if (ret) {
 185                         DEBUG(1,("gensec_krb5_start: krb5_sockaddr2address (local) failed (%s)\n",
 186                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 187                                                             ret, gensec_krb5_state)));
 188                         talloc_free(gensec_krb5_state);
 189                         return NT_STATUS_INTERNAL_ERROR;
 190                 }
 191         }
 192
 193         ret = krb5_auth_con_setaddrs(gensec_krb5_state->smb_krb5_context->krb5_context,
 194                                      gensec_krb5_state->auth_context,
 195                                      tlocal_addr ? &my_krb5_addr : NULL,
 196                                      tremote_addr ? &peer_krb5_addr : NULL);
 197         if (ret) {
 198                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_setaddrs failed (%s)\n",
 199                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 200                                                     ret, gensec_krb5_state)));
 201                 talloc_free(gensec_krb5_state);
 202                 return NT_STATUS_INTERNAL_ERROR;
 203         }
 204
 205         return NT_STATUS_OK;
 206 }
 207
 208 static NTSTATUS gensec_krb5_common_server_start(struct gensec_security *gensec_security, bool gssapi)
 209 {
 210         NTSTATUS nt_status;
 211         struct gensec_krb5_state *gensec_krb5_state;
 212
 213         nt_status = gensec_krb5_start(gensec_security, gssapi);
 214         if (!NT_STATUS_IS_OK(nt_status)) {
 215                 return nt_status;
 216         }
 217
 218         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 219         gensec_krb5_state->state_position = GENSEC_KRB5_SERVER_START;
 220
 221         return NT_STATUS_OK;
 222 }
 223
 224 static NTSTATUS gensec_krb5_server_start(struct gensec_security *gensec_security)
 225 {
 226         return gensec_krb5_common_server_start(gensec_security, false);
 227 }
 228
 229 static NTSTATUS gensec_fake_gssapi_krb5_server_start(struct gensec_security *gensec_security)
 230 {
 231         return gensec_krb5_common_server_start(gensec_security, true);
 232 }
 233
 234 static NTSTATUS gensec_krb5_common_client_start(struct gensec_security *gensec_security, bool gssapi)
 235 {
 236         struct gensec_krb5_state *gensec_krb5_state;
 237         krb5_error_code ret;
 238         NTSTATUS nt_status;
 239         struct ccache_container *ccache_container;
 240         const char *hostname;
 241         const char *error_string;
 242         const char *principal;
 243         krb5_data in_data;
 244         struct tevent_context *previous_ev;
 245
 246         hostname = gensec_get_target_hostname(gensec_security);
 247         if (!hostname) {
 248                 DEBUG(1, ("Could not determine hostname for target computer, cannot use kerberos\n"));
 249                 return NT_STATUS_INVALID_PARAMETER;
 250         }
 251         if (is_ipaddress(hostname)) {
 252                 DEBUG(2, ("Cannot do krb5 to an IP address"));
 253                 return NT_STATUS_INVALID_PARAMETER;
 254         }
 255         if (strcmp(hostname, "localhost") == 0) {
 256                 DEBUG(2, ("krb5 to 'localhost' does not make sense"));
 257                 return NT_STATUS_INVALID_PARAMETER;
 258         }
 259
 260         nt_status = gensec_krb5_start(gensec_security, gssapi);
 261         if (!NT_STATUS_IS_OK(nt_status)) {
 262                 return nt_status;
 263         }
 264
 265         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 266         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_START;
 267         gensec_krb5_state->ap_req_options = AP_OPTS_USE_SUBKEY;
 268
 269         if (gensec_krb5_state->gssapi) {
 270                 /* The Fake GSSAPI modal emulates Samba3, which does not do mutual authentication */
 271                 if (gensec_setting_bool(gensec_security->settings, "gensec_fake_gssapi_krb5", "mutual", false)) {
 272                         gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 273                 }
 274         } else {
 275                 /* The wrapping for KPASSWD (a user of the raw KRB5 API) should be mutually authenticated */
 276                 if (gensec_setting_bool(gensec_security->settings, "gensec_krb5", "mutual", true)) {
 277                         gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 278                 }
 279         }
 280
 281         principal = gensec_get_target_principal(gensec_security);
 282
 283         ret = cli_credentials_get_ccache(gensec_get_credentials(gensec_security),
 284                                          gensec_security->event_ctx,
 285                                          gensec_security->settings->lp_ctx, &ccache_container, &error_string);
 286         switch (ret) {
 287         case 0:
 288                 break;
 289         case KRB5KDC_ERR_PREAUTH_FAILED:
 290         case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
 291                 return NT_STATUS_LOGON_FAILURE;
 292         case KRB5_KDC_UNREACH:
 293                 DEBUG(3, ("Cannot reach a KDC we require to contact %s: %s\n", principal, error_string));
 294                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 295         case KRB5_CC_NOTFOUND:
 296         case KRB5_CC_END:
 297                 DEBUG(3, ("Error preparing credentials we require to contact %s : %s\n", principal, error_string));
 298                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 299         default:
 300                 DEBUG(1, ("gensec_krb5_start: Aquiring initiator credentials failed: %s\n", error_string));
 301                 return NT_STATUS_UNSUCCESSFUL;
 302         }
 303         in_data.length = 0;
 304
 305         /* Do this every time, in case we have weird recursive issues here */
 306         ret = smb_krb5_context_set_event_ctx(gensec_krb5_state->smb_krb5_context, gensec_security->event_ctx, &previous_ev);
 307         if (ret != 0) {
 308                 DEBUG(1, ("gensec_krb5_start: Setting event context failed\n"));
 309                 return NT_STATUS_NO_MEMORY;
 310         }
 311         if (principal) {
 312                 krb5_principal target_principal;
 313                 ret = krb5_parse_name(gensec_krb5_state->smb_krb5_context->krb5_context, principal,
 314                                       &target_principal);
 315                 if (ret == 0) {
 316                         ret = krb5_mk_req_exact(gensec_krb5_state->smb_krb5_context->krb5_context,
 317                                                 &gensec_krb5_state->auth_context,
 318                                                 gensec_krb5_state->ap_req_options,
 319                                                 target_principal,
 320                                                 &in_data, ccache_container->ccache,
 321                                                 &gensec_krb5_state->enc_ticket);
 322                         krb5_free_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
 323                                             target_principal);
 324                 }
 325         } else {
 326                 ret = krb5_mk_req(gensec_krb5_state->smb_krb5_context->krb5_context,
 327                                   &gensec_krb5_state->auth_context,
 328                                   gensec_krb5_state->ap_req_options,
 329                                   gensec_get_target_service(gensec_security),
 330                                   hostname,
 331                                   &in_data, ccache_container->ccache,
 332                                   &gensec_krb5_state->enc_ticket);
 333         }
 334
 335         smb_krb5_context_remove_event_ctx(gensec_krb5_state->smb_krb5_context, previous_ev, gensec_security->event_ctx);
 336
 337         switch (ret) {
 338         case 0:
 339                 return NT_STATUS_OK;
 340         case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
 341                 DEBUG(3, ("Server [%s] is not registered with our KDC: %s\n",
 342                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 343                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 344         case KRB5_KDC_UNREACH:
 345                 DEBUG(3, ("Cannot reach a KDC we require to contact host [%s]: %s\n",
 346                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 347                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 348         case KRB5KDC_ERR_PREAUTH_FAILED:
 349         case KRB5KRB_AP_ERR_TKT_EXPIRED:
 350         case KRB5_CC_END:
 351                 /* Too much clock skew - we will need to kinit to re-skew the clock */
 352         case KRB5KRB_AP_ERR_SKEW:
 353         case KRB5_KDCREP_SKEW:
 354         {
 355                 DEBUG(3, ("kerberos (mk_req) failed: %s\n",
 356                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 357                 /*fall through*/
 358         }
 359
 360         /* just don't print a message for these really ordinary messages */
 361         case KRB5_FCC_NOFILE:
 362         case KRB5_CC_NOTFOUND:
 363         case ENOENT:
 364
 365                 return NT_STATUS_UNSUCCESSFUL;
 366                 break;
 367
 368         default:
 369                 DEBUG(0, ("kerberos: %s\n",
 370                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 371                 return NT_STATUS_UNSUCCESSFUL;
 372         }
 373 }
 374
 375 static NTSTATUS gensec_krb5_client_start(struct gensec_security *gensec_security)
 376 {
 377         return gensec_krb5_common_client_start(gensec_security, false);
 378 }
 379
 380 static NTSTATUS gensec_fake_gssapi_krb5_client_start(struct gensec_security *gensec_security)
 381 {
 382         return gensec_krb5_common_client_start(gensec_security, true);
 383 }
 384
 385 /**
 386  * Check if the packet is one for this mechansim
 387  *
 388  * @param gensec_security GENSEC state
 389  * @param in The request, as a DATA_BLOB
 390  * @return Error, INVALID_PARAMETER if it's not a packet for us
 391  *                or NT_STATUS_OK if the packet is ok.
 392  */
 393
 394 static NTSTATUS gensec_fake_gssapi_krb5_magic(struct gensec_security *gensec_security,
 395                                   const DATA_BLOB *in)
 396 {
 397         if (gensec_gssapi_check_oid(in, GENSEC_OID_KERBEROS5)) {
 398                 return NT_STATUS_OK;
 399         } else {
 400                 return NT_STATUS_INVALID_PARAMETER;
 401         }
 402 }
 403
 404
 405 /**
 406  * Next state function for the Krb5 GENSEC mechanism
 407  *
 408  * @param gensec_krb5_state KRB5 State
 409  * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
 410  * @param in The request, as a DATA_BLOB
 411  * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
 412  * @return Error, MORE_PROCESSING_REQUIRED if a reply is sent,
 413  *                or NT_STATUS_OK if the user is authenticated.
 414  */
 415
 416 static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 417                                    TALLOC_CTX *out_mem_ctx,
 418                                    const DATA_BLOB in, DATA_BLOB *out)
 419 {
 420         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 421         krb5_error_code ret = 0;
 422         NTSTATUS nt_status;
 423
 424         switch (gensec_krb5_state->state_position) {
 425         case GENSEC_KRB5_CLIENT_START:
 426         {
 427                 DATA_BLOB unwrapped_out;
 428
 429                 if (gensec_krb5_state->gssapi) {
 430                         unwrapped_out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 431
 432                         /* wrap that up in a nice GSS-API wrapping */
 433                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REQ);
 434                 } else {
 435                         *out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 436                 }
 437                 if (gensec_krb5_state->ap_req_options & AP_OPTS_MUTUAL_REQUIRED) {
 438                         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_MUTUAL_AUTH;
 439                         nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
 440                 } else {
 441                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 442                         nt_status = NT_STATUS_OK;
 443                 }
 444                 return nt_status;
 445         }
 446
 447         case GENSEC_KRB5_CLIENT_MUTUAL_AUTH:
 448         {
 449                 DATA_BLOB unwrapped_in;
 450                 krb5_data inbuf;
 451                 krb5_ap_rep_enc_part *repl = NULL;
 452                 uint8_t tok_id[2];
 453
 454                 if (gensec_krb5_state->gssapi) {
 455                         if (!gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 456                                 DEBUG(1,("gensec_gssapi_parse_krb5_wrap(mutual authentication) failed to parse\n"));
 457                                 dump_data_pw("Mutual authentication message:\n", in.data, in.length);
 458                                 return NT_STATUS_INVALID_PARAMETER;
 459                         }
 460                 } else {
 461                         unwrapped_in = in;
 462                 }
 463                 /* TODO: check the tok_id */
 464
 465                 inbuf.data = unwrapped_in.data;
 466                 inbuf.length = unwrapped_in.length;
 467                 ret = krb5_rd_rep(gensec_krb5_state->smb_krb5_context->krb5_context,
 468                                   gensec_krb5_state->auth_context,
 469                                   &inbuf, &repl);
 470                 if (ret) {
 471                         DEBUG(1,("krb5_rd_rep (mutual authentication) failed (%s)\n",
 472                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, out_mem_ctx)));
 473                         dump_data_pw("Mutual authentication message:\n", (uint8_t *)inbuf.data, inbuf.length);
 474                         nt_status = NT_STATUS_ACCESS_DENIED;
 475                 } else {
 476                         *out = data_blob(NULL, 0);
 477                         nt_status = NT_STATUS_OK;
 478                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 479                 }
 480                 if (repl) {
 481                         krb5_free_ap_rep_enc_part(gensec_krb5_state->smb_krb5_context->krb5_context, repl);
 482                 }
 483                 return nt_status;
 484         }
 485
 486         case GENSEC_KRB5_SERVER_START:
 487         {
 488                 DATA_BLOB unwrapped_in;
 489                 DATA_BLOB unwrapped_out = data_blob(NULL, 0);
 490                 krb5_data inbuf, outbuf;
 491                 uint8_t tok_id[2];
 492                 struct keytab_container *keytab;
 493                 krb5_principal server_in_keytab;
 494                 const char *error_string;
 495                 enum credentials_obtained obtained;
 496
 497                 if (!in.data) {
 498                         return NT_STATUS_INVALID_PARAMETER;
 499                 }
 500
 501                 /* Grab the keytab, however generated */
 502                 ret = cli_credentials_get_keytab(gensec_get_credentials(gensec_security),
 503                                                  gensec_security->settings->lp_ctx, &keytab);
 504                 if (ret) {
 505                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 506                 }
 507
 508                 /* This ensures we lookup the correct entry in that keytab */
 509                 ret = principal_from_credentials(out_mem_ctx, gensec_get_credentials(gensec_security),
 510                                                  gensec_krb5_state->smb_krb5_context,
 511                                                  &server_in_keytab, &obtained, &error_string);
 512
 513                 if (ret) {
 514                         DEBUG(2,("Failed to make credentials from principal: %s\n", error_string));
 515                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 516                 }
 517
 518                 /* Parse the GSSAPI wrapping, if it's there... (win2k3 allows it to be omited) */
 519                 if (gensec_krb5_state->gssapi
 520                     && gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 521                         inbuf.data = unwrapped_in.data;
 522                         inbuf.length = unwrapped_in.length;
 523                 } else {
 524                         inbuf.data = in.data;
 525                         inbuf.length = in.length;
 526                 }
 527
 528                 ret = smb_rd_req_return_stuff(gensec_krb5_state->smb_krb5_context->krb5_context,
 529                                               &gensec_krb5_state->auth_context,
 530                                               &inbuf, keytab->keytab, server_in_keytab,
 531                                               &outbuf,
 532                                               &gensec_krb5_state->ticket,
 533                                               &gensec_krb5_state->keyblock);
 534
 535                 if (ret) {
 536                         return NT_STATUS_LOGON_FAILURE;
 537                 }
 538                 unwrapped_out.data = (uint8_t *)outbuf.data;
 539                 unwrapped_out.length = outbuf.length;
 540                 gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 541                 /* wrap that up in a nice GSS-API wrapping */
 542                 if (gensec_krb5_state->gssapi) {
 543                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REP);
 544                 } else {
 545                         *out = data_blob_talloc(out_mem_ctx, outbuf.data, outbuf.length);
 546                 }
 547                 krb5_data_free(&outbuf);
 548                 return NT_STATUS_OK;
 549         }
 550
 551         case GENSEC_KRB5_DONE:
 552         default:
 553                 /* Asking too many times... */
 554                 return NT_STATUS_INVALID_PARAMETER;
 555         }
 556 }
 557
 558 static NTSTATUS gensec_krb5_session_key(struct gensec_security *gensec_security,
 559                                         DATA_BLOB *session_key)
 560 {
 561         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 562         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 563         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 564         krb5_keyblock *skey;
 565         krb5_error_code err = -1;
 566
 567         if (gensec_krb5_state->state_position != GENSEC_KRB5_DONE) {
 568                 return NT_STATUS_NO_USER_SESSION_KEY;
 569         }
 570
 571         if (gensec_krb5_state->session_key.data) {
 572                 *session_key = gensec_krb5_state->session_key;
 573                 return NT_STATUS_OK;
 574         }
 575
 576         switch (gensec_security->gensec_role) {
 577         case GENSEC_CLIENT:
 578                 err = krb5_auth_con_getlocalsubkey(context, auth_context, &skey);
 579                 break;
 580         case GENSEC_SERVER:
 581                 err = krb5_auth_con_getremotesubkey(context, auth_context, &skey);
 582                 break;
 583         }
 584         if (err == 0 && skey != NULL) {
 585                 DEBUG(10, ("Got KRB5 session key of length %d\n",
 586                            (int)KRB5_KEY_LENGTH(skey)));
 587                 gensec_krb5_state->session_key = data_blob_talloc(gensec_krb5_state,
 588                                                 KRB5_KEY_DATA(skey), KRB5_KEY_LENGTH(skey));
 589                 *session_key = gensec_krb5_state->session_key;
 590                 dump_data_pw("KRB5 Session Key:\n", session_key->data, session_key->length);
 591
 592                 krb5_free_keyblock(context, skey);
 593                 return NT_STATUS_OK;
 594         } else {
 595                 DEBUG(10, ("KRB5 error getting session key %d\n", err));
 596                 return NT_STATUS_NO_USER_SESSION_KEY;
 597         }
 598 }
 599
 600 static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security,
 601                                          struct auth_session_info **_session_info)
 602 {
 603         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 604         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 605         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 606         struct auth_user_info_dc *user_info_dc = NULL;
 607         struct auth_session_info *session_info = NULL;
 608         struct PAC_LOGON_INFO *logon_info;
 609
 610         krb5_principal client_principal;
 611         char *principal_string;
 612
 613         DATA_BLOB pac;
 614         krb5_data pac_data;
 615
 616         krb5_error_code ret;
 617
 618         TALLOC_CTX *mem_ctx = talloc_new(gensec_security);
 619         if (!mem_ctx) {
 620                 return NT_STATUS_NO_MEMORY;
 621         }
 622
 623         ret = krb5_ticket_get_client(context, gensec_krb5_state->ticket, &client_principal);
 624         if (ret) {
 625                 DEBUG(5, ("krb5_ticket_get_client failed to get cleint principal: %s\n",
 626                           smb_get_krb5_error_message(context,
 627                                                      ret, mem_ctx)));
 628                 talloc_free(mem_ctx);
 629                 return NT_STATUS_NO_MEMORY;
 630         }
 631
 632         ret = krb5_unparse_name(gensec_krb5_state->smb_krb5_context->krb5_context,
 633                                 client_principal, &principal_string);
 634         if (ret) {
 635                 DEBUG(1, ("Unable to parse client principal: %s\n",
 636                           smb_get_krb5_error_message(context,
 637                                                      ret, mem_ctx)));
 638                 krb5_free_principal(context, client_principal);
 639                 talloc_free(mem_ctx);
 640                 return NT_STATUS_NO_MEMORY;
 641         }
 642
 643         ret = krb5_ticket_get_authorization_data_type(context, gensec_krb5_state->ticket,
 644                                                       KRB5_AUTHDATA_WIN2K_PAC,
 645                                                       &pac_data);
 646
 647         if (ret && gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
 648                 DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access: %s \n",
 649                           principal_string,
 650                           smb_get_krb5_error_message(context,
 651                                                      ret, mem_ctx)));
 652                 free(principal_string);
 653                 krb5_free_principal(context, client_principal);
 654                 talloc_free(mem_ctx);
 655                 return NT_STATUS_ACCESS_DENIED;
 656         } else if (ret) {
 657                 /* NO pac */
 658                 DEBUG(5, ("krb5_ticket_get_authorization_data_type failed to find PAC: %s\n",
 659                           smb_get_krb5_error_message(context,
 660                                                      ret, mem_ctx)));
 661                 if (gensec_security->auth_context &&
 662                     !gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
 663                         DEBUG(1, ("Unable to find PAC for %s, resorting to local user lookup: %s",
 664                                   principal_string, smb_get_krb5_error_message(context,
 665                                                      ret, mem_ctx)));
 666                         nt_status = gensec_security->auth_context->get_user_info_dc_principal(mem_ctx,
 667                                                                                              gensec_security->auth_context,
 668                                                                                              principal_string,
 669                                                                                              NULL, &user_info_dc);
 670                         if (!NT_STATUS_IS_OK(nt_status)) {
 671                                 free(principal_string);
 672                                 krb5_free_principal(context, client_principal);
 673                                 talloc_free(mem_ctx);
 674                                 return nt_status;
 675                         }
 676                 } else {
 677                         DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access\n",
 678                                   principal_string));
 679                         free(principal_string);
 680                         krb5_free_principal(context, client_principal);
 681                         talloc_free(mem_ctx);
 682                         return NT_STATUS_ACCESS_DENIED;
 683                 }
 684         } else {
 685                 /* Found pac */
 686                 union netr_Validation validation;
 687
 688                 pac = data_blob_talloc(mem_ctx, pac_data.data, pac_data.length);
 689                 if (!pac.data) {
 690                         free(principal_string);
 691                         krb5_free_principal(context, client_principal);
 692                         talloc_free(mem_ctx);
 693                         return NT_STATUS_NO_MEMORY;
 694                 }
 695
 696                 /* decode and verify the pac */
 697                 nt_status = kerberos_pac_logon_info(gensec_krb5_state,
 698                                                     &logon_info, pac,
 699                                                     gensec_krb5_state->smb_krb5_context->krb5_context,
 700                                                     NULL, gensec_krb5_state->keyblock,
 701                                                     client_principal,
 702                                                     gensec_krb5_state->ticket->ticket.authtime, NULL);
 703
 704                 if (!NT_STATUS_IS_OK(nt_status)) {
 705                         free(principal_string);
 706                         krb5_free_principal(context, client_principal);
 707                         talloc_free(mem_ctx);
 708                         return nt_status;
 709                 }
 710
 711                 validation.sam3 = &logon_info->info3;
 712                 nt_status = make_user_info_dc_netlogon_validation(mem_ctx,
 713                                                                  NULL,
 714                                                                  3, &validation,
 715                                                                  &user_info_dc);
 716                 if (!NT_STATUS_IS_OK(nt_status)) {
 717                         free(principal_string);
 718                         krb5_free_principal(context, client_principal);
 719                         talloc_free(mem_ctx);
 720                         return nt_status;
 721                 }
 722         }
 723
 724         free(principal_string);
 725         krb5_free_principal(context, client_principal);
 726
 727         /* references the user_info_dc into the session_info */
 728         nt_status = gensec_generate_session_info(mem_ctx, gensec_security, user_info_dc, &session_info);
 729
 730         if (!NT_STATUS_IS_OK(nt_status)) {
 731                 talloc_free(mem_ctx);
 732                 return nt_status;
 733         }
 734
 735         nt_status = gensec_krb5_session_key(gensec_security, &session_info->session_key);
 736
 737         if (!NT_STATUS_IS_OK(nt_status)) {
 738                 talloc_free(mem_ctx);
 739                 return nt_status;
 740         }
 741
 742         *_session_info = session_info;
 743
 744         talloc_steal(gensec_krb5_state, session_info);
 745         talloc_free(mem_ctx);
 746         return NT_STATUS_OK;
 747 }
 748
 749 static NTSTATUS gensec_krb5_wrap(struct gensec_security *gensec_security,
 750                                    TALLOC_CTX *mem_ctx,
 751                                    const DATA_BLOB *in,
 752                                    DATA_BLOB *out)
 753 {
 754         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 755         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 756         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 757         krb5_error_code ret;
 758         krb5_data input, output;
 759         input.length = in->length;
 760         input.data = in->data;
 761
 762         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 763                 ret = krb5_mk_priv(context, auth_context, &input, &output, NULL);
 764                 if (ret) {
 765                         DEBUG(1, ("krb5_mk_priv failed: %s\n",
 766                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 767                                                              ret, mem_ctx)));
 768                         return NT_STATUS_ACCESS_DENIED;
 769                 }
 770                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 771
 772                 krb5_data_free(&output);
 773         } else {
 774                 return NT_STATUS_ACCESS_DENIED;
 775         }
 776         return NT_STATUS_OK;
 777 }
 778
 779 static NTSTATUS gensec_krb5_unwrap(struct gensec_security *gensec_security,
 780                                      TALLOC_CTX *mem_ctx,
 781                                      const DATA_BLOB *in,
 782                                      DATA_BLOB *out)
 783 {
 784         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 785         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 786         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 787         krb5_error_code ret;
 788         krb5_data input, output;
 789         krb5_replay_data replay;
 790         input.length = in->length;
 791         input.data = in->data;
 792
 793         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 794                 ret = krb5_rd_priv(context, auth_context, &input, &output, &replay);
 795                 if (ret) {
 796                         DEBUG(1, ("krb5_rd_priv failed: %s\n",
 797                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 798                                                              ret, mem_ctx)));
 799                         return NT_STATUS_ACCESS_DENIED;
 800                 }
 801                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 802
 803                 krb5_data_free(&output);
 804         } else {
 805                 return NT_STATUS_ACCESS_DENIED;
 806         }
 807         return NT_STATUS_OK;
 808 }
 809
 810 static bool gensec_krb5_have_feature(struct gensec_security *gensec_security,
 811                                      uint32_t feature)
 812 {
 813         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 814         if (feature & GENSEC_FEATURE_SESSION_KEY) {
 815                 return true;
 816         }
 817         if (!gensec_krb5_state->gssapi &&
 818             (feature & GENSEC_FEATURE_SEAL)) {
 819                 return true;
 820         }
 821
 822         return false;
 823 }
 824
 825 static const char *gensec_krb5_oids[] = {
 826         GENSEC_OID_KERBEROS5,
 827         GENSEC_OID_KERBEROS5_OLD,
 828         NULL
 829 };
 830
 831 static const struct gensec_security_ops gensec_fake_gssapi_krb5_security_ops = {
 832         .name           = "fake_gssapi_krb5",
 833         .auth_type      = DCERPC_AUTH_TYPE_KRB5,
 834         .oid            = gensec_krb5_oids,
 835         .client_start   = gensec_fake_gssapi_krb5_client_start,
 836         .server_start   = gensec_fake_gssapi_krb5_server_start,
 837         .update         = gensec_krb5_update,
 838         .magic          = gensec_fake_gssapi_krb5_magic,
 839         .session_key    = gensec_krb5_session_key,
 840         .session_info   = gensec_krb5_session_info,
 841         .have_feature   = gensec_krb5_have_feature,
 842         .enabled        = false,
 843         .kerberos       = true,
 844         .priority       = GENSEC_KRB5
 845 };
 846
 847 static const struct gensec_security_ops gensec_krb5_security_ops = {
 848         .name           = "krb5",
 849         .client_start   = gensec_krb5_client_start,
 850         .server_start   = gensec_krb5_server_start,
 851         .update         = gensec_krb5_update,
 852         .session_key    = gensec_krb5_session_key,
 853         .session_info   = gensec_krb5_session_info,
 854         .have_feature   = gensec_krb5_have_feature,
 855         .wrap           = gensec_krb5_wrap,
 856         .unwrap         = gensec_krb5_unwrap,
 857         .enabled        = true,
 858         .kerberos       = true,
 859         .priority       = GENSEC_KRB5
 860 };
 861
 862 _PUBLIC_ NTSTATUS gensec_krb5_init(void)
 863 {
 864         NTSTATUS ret;
 865
 866         ret = gensec_register(&gensec_krb5_security_ops);
 867         if (!NT_STATUS_IS_OK(ret)) {
 868                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 869                         gensec_krb5_security_ops.name));
 870                 return ret;
 871         }
 872
 873         ret = gensec_register(&gensec_fake_gssapi_krb5_security_ops);
 874         if (!NT_STATUS_IS_OK(ret)) {
 875                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 876                         gensec_krb5_security_ops.name));
 877                 return ret;
 878         }
 879
 880         return ret;
 881 }