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
  43 _PUBLIC_ NTSTATUS gensec_krb5_init(void);
  44
  45 enum GENSEC_KRB5_STATE {
  46         GENSEC_KRB5_SERVER_START,
  47         GENSEC_KRB5_CLIENT_START,
  48         GENSEC_KRB5_CLIENT_MUTUAL_AUTH,
  49         GENSEC_KRB5_DONE
  50 };
  51
  52 struct gensec_krb5_state {
  53         enum GENSEC_KRB5_STATE state_position;
  54         struct smb_krb5_context *smb_krb5_context;
  55         krb5_auth_context auth_context;
  56         krb5_data enc_ticket;
  57         krb5_keyblock *keyblock;
  58         krb5_ticket *ticket;
  59         bool gssapi;
  60         krb5_flags ap_req_options;
  61 };
  62
  63 static int gensec_krb5_destroy(struct gensec_krb5_state *gensec_krb5_state)
  64 {
  65         if (!gensec_krb5_state->smb_krb5_context) {
  66                 /* We can't clean anything else up unless we started up this far */
  67                 return 0;
  68         }
  69         if (gensec_krb5_state->enc_ticket.length) {
  70                 kerberos_free_data_contents(gensec_krb5_state->smb_krb5_context->krb5_context,
  71                                             &gensec_krb5_state->enc_ticket);
  72         }
  73
  74         if (gensec_krb5_state->ticket) {
  75                 krb5_free_ticket(gensec_krb5_state->smb_krb5_context->krb5_context,
  76                                  gensec_krb5_state->ticket);
  77         }
  78
  79         /* ccache freed in a child destructor */
  80
  81         krb5_free_keyblock(gensec_krb5_state->smb_krb5_context->krb5_context,
  82                            gensec_krb5_state->keyblock);
  83
  84         if (gensec_krb5_state->auth_context) {
  85                 krb5_auth_con_free(gensec_krb5_state->smb_krb5_context->krb5_context,
  86                                    gensec_krb5_state->auth_context);
  87         }
  88
  89         return 0;
  90 }
  91
  92 static NTSTATUS gensec_krb5_start(struct gensec_security *gensec_security, bool gssapi)
  93 {
  94         krb5_error_code ret;
  95         struct gensec_krb5_state *gensec_krb5_state;
  96         struct cli_credentials *creds;
  97         const struct tsocket_address *tlocal_addr, *tremote_addr;
  98         krb5_address my_krb5_addr, peer_krb5_addr;
  99
 100         creds = gensec_get_credentials(gensec_security);
 101         if (!creds) {
 102                 return NT_STATUS_INVALID_PARAMETER;
 103         }
 104
 105         gensec_krb5_state = talloc(gensec_security, struct gensec_krb5_state);
 106         if (!gensec_krb5_state) {
 107                 return NT_STATUS_NO_MEMORY;
 108         }
 109
 110         gensec_security->private_data = gensec_krb5_state;
 111         gensec_krb5_state->smb_krb5_context = NULL;
 112         gensec_krb5_state->auth_context = NULL;
 113         gensec_krb5_state->ticket = NULL;
 114         ZERO_STRUCT(gensec_krb5_state->enc_ticket);
 115         gensec_krb5_state->keyblock = NULL;
 116         gensec_krb5_state->gssapi = gssapi;
 117
 118         talloc_set_destructor(gensec_krb5_state, gensec_krb5_destroy);
 119
 120         if (cli_credentials_get_krb5_context(creds,
 121                                              gensec_security->settings->lp_ctx, &gensec_krb5_state->smb_krb5_context)) {
 122                 talloc_free(gensec_krb5_state);
 123                 return NT_STATUS_INTERNAL_ERROR;
 124         }
 125
 126         ret = krb5_auth_con_init(gensec_krb5_state->smb_krb5_context->krb5_context, &gensec_krb5_state->auth_context);
 127         if (ret) {
 128                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_init failed (%s)\n",
 129                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 130                                                     ret, gensec_krb5_state)));
 131                 talloc_free(gensec_krb5_state);
 132                 return NT_STATUS_INTERNAL_ERROR;
 133         }
 134
 135         ret = krb5_auth_con_setflags(gensec_krb5_state->smb_krb5_context->krb5_context,
 136                                      gensec_krb5_state->auth_context,
 137                                      KRB5_AUTH_CONTEXT_DO_SEQUENCE);
 138         if (ret) {
 139                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_setflags failed (%s)\n",
 140                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 141                                                     ret, gensec_krb5_state)));
 142                 talloc_free(gensec_krb5_state);
 143                 return NT_STATUS_INTERNAL_ERROR;
 144         }
 145
 146         tlocal_addr = gensec_get_local_address(gensec_security);
 147         if (tlocal_addr) {
 148                 ssize_t socklen;
 149                 struct sockaddr_storage ss;
 150
 151                 socklen = tsocket_address_bsd_sockaddr(tlocal_addr,
 152                                 (struct sockaddr *) &ss,
 153                                 sizeof(struct sockaddr_storage));
 154                 if (socklen < 0) {
 155                         talloc_free(gensec_krb5_state);
 156                         return NT_STATUS_INTERNAL_ERROR;
 157                 }
 158                 ret = krb5_sockaddr2address(gensec_krb5_state->smb_krb5_context->krb5_context,
 159                                 (const struct sockaddr *) &ss, &my_krb5_addr);
 160                 if (ret) {
 161                         DEBUG(1,("gensec_krb5_start: krb5_sockaddr2address (local) failed (%s)\n",
 162                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 163                                                             ret, gensec_krb5_state)));
 164                         talloc_free(gensec_krb5_state);
 165                         return NT_STATUS_INTERNAL_ERROR;
 166                 }
 167         }
 168
 169         tremote_addr = gensec_get_remote_address(gensec_security);
 170         if (tremote_addr) {
 171                 ssize_t socklen;
 172                 struct sockaddr_storage ss;
 173
 174                 socklen = tsocket_address_bsd_sockaddr(tremote_addr,
 175                                 (struct sockaddr *) &ss,
 176                                 sizeof(struct sockaddr_storage));
 177                 if (socklen < 0) {
 178                         talloc_free(gensec_krb5_state);
 179                         return NT_STATUS_INTERNAL_ERROR;
 180                 }
 181                 ret = krb5_sockaddr2address(gensec_krb5_state->smb_krb5_context->krb5_context,
 182                                 (const struct sockaddr *) &ss, &peer_krb5_addr);
 183                 if (ret) {
 184                         DEBUG(1,("gensec_krb5_start: krb5_sockaddr2address (local) failed (%s)\n",
 185                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 186                                                             ret, gensec_krb5_state)));
 187                         talloc_free(gensec_krb5_state);
 188                         return NT_STATUS_INTERNAL_ERROR;
 189                 }
 190         }
 191
 192         ret = krb5_auth_con_setaddrs(gensec_krb5_state->smb_krb5_context->krb5_context,
 193                                      gensec_krb5_state->auth_context,
 194                                      tlocal_addr ? &my_krb5_addr : NULL,
 195                                      tremote_addr ? &peer_krb5_addr : NULL);
 196         if (ret) {
 197                 DEBUG(1,("gensec_krb5_start: krb5_auth_con_setaddrs failed (%s)\n",
 198                          smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 199                                                     ret, gensec_krb5_state)));
 200                 talloc_free(gensec_krb5_state);
 201                 return NT_STATUS_INTERNAL_ERROR;
 202         }
 203
 204         return NT_STATUS_OK;
 205 }
 206
 207 static NTSTATUS gensec_krb5_common_server_start(struct gensec_security *gensec_security, bool gssapi)
 208 {
 209         NTSTATUS nt_status;
 210         struct gensec_krb5_state *gensec_krb5_state;
 211
 212         nt_status = gensec_krb5_start(gensec_security, gssapi);
 213         if (!NT_STATUS_IS_OK(nt_status)) {
 214                 return nt_status;
 215         }
 216
 217         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 218         gensec_krb5_state->state_position = GENSEC_KRB5_SERVER_START;
 219
 220         return NT_STATUS_OK;
 221 }
 222
 223 static NTSTATUS gensec_krb5_server_start(struct gensec_security *gensec_security)
 224 {
 225         return gensec_krb5_common_server_start(gensec_security, false);
 226 }
 227
 228 static NTSTATUS gensec_fake_gssapi_krb5_server_start(struct gensec_security *gensec_security)
 229 {
 230         return gensec_krb5_common_server_start(gensec_security, true);
 231 }
 232
 233 static NTSTATUS gensec_krb5_common_client_start(struct gensec_security *gensec_security, bool gssapi)
 234 {
 235         const char *hostname;
 236         struct gensec_krb5_state *gensec_krb5_state;
 237         NTSTATUS nt_status;
 238         hostname = gensec_get_target_hostname(gensec_security);
 239         if (!hostname) {
 240                 DEBUG(1, ("Could not determine hostname for target computer, cannot use kerberos\n"));
 241                 return NT_STATUS_INVALID_PARAMETER;
 242         }
 243         if (is_ipaddress(hostname)) {
 244                 DEBUG(2, ("Cannot do krb5 to an IP address"));
 245                 return NT_STATUS_INVALID_PARAMETER;
 246         }
 247         if (strcmp(hostname, "localhost") == 0) {
 248                 DEBUG(2, ("krb5 to 'localhost' does not make sense"));
 249                 return NT_STATUS_INVALID_PARAMETER;
 250         }
 251
 252         nt_status = gensec_krb5_start(gensec_security, gssapi);
 253         if (!NT_STATUS_IS_OK(nt_status)) {
 254                 return nt_status;
 255         }
 256
 257         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 258         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_START;
 259         gensec_krb5_state->ap_req_options = AP_OPTS_USE_SUBKEY;
 260
 261         if (gensec_krb5_state->gssapi) {
 262                 /* The Fake GSSAPI modal emulates Samba3, which does not do mutual authentication */
 263                 if (gensec_setting_bool(gensec_security->settings, "gensec_fake_gssapi_krb5", "mutual", false)) {
 264                         gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 265                 }
 266         } else {
 267                 /* The wrapping for KPASSWD (a user of the raw KRB5 API) should be mutually authenticated */
 268                 if (gensec_setting_bool(gensec_security->settings, "gensec_krb5", "mutual", true)) {
 269                         gensec_krb5_state->ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
 270                 }
 271         }
 272         return NT_STATUS_OK;
 273 }
 274
 275 static NTSTATUS gensec_krb5_common_client_creds(struct gensec_security *gensec_security,
 276                                                 struct tevent_context *ev,
 277                                                 bool gssapi)
 278 {
 279         struct gensec_krb5_state *gensec_krb5_state;
 280         krb5_error_code ret;
 281         struct ccache_container *ccache_container;
 282         const char *error_string;
 283         const char *principal;
 284         const char *hostname;
 285         krb5_data in_data;
 286         struct tevent_context *previous_ev;
 287
 288         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 289
 290         principal = gensec_get_target_principal(gensec_security);
 291         hostname = gensec_get_target_hostname(gensec_security);
 292
 293         ret = cli_credentials_get_ccache(gensec_get_credentials(gensec_security),
 294                                          ev,
 295                                          gensec_security->settings->lp_ctx, &ccache_container, &error_string);
 296         switch (ret) {
 297         case 0:
 298                 break;
 299         case KRB5KDC_ERR_PREAUTH_FAILED:
 300         case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
 301                 return NT_STATUS_LOGON_FAILURE;
 302         case KRB5_KDC_UNREACH:
 303                 DEBUG(3, ("Cannot reach a KDC we require to contact %s: %s\n", principal, error_string));
 304                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 305         case KRB5_CC_NOTFOUND:
 306         case KRB5_CC_END:
 307                 DEBUG(3, ("Error preparing credentials we require to contact %s : %s\n", principal, error_string));
 308                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 309         default:
 310                 DEBUG(1, ("gensec_krb5_start: Aquiring initiator credentials failed: %s\n", error_string));
 311                 return NT_STATUS_UNSUCCESSFUL;
 312         }
 313         in_data.length = 0;
 314
 315         /* Do this every time, in case we have weird recursive issues here */
 316         ret = smb_krb5_context_set_event_ctx(gensec_krb5_state->smb_krb5_context, ev, &previous_ev);
 317         if (ret != 0) {
 318                 DEBUG(1, ("gensec_krb5_start: Setting event context failed\n"));
 319                 return NT_STATUS_NO_MEMORY;
 320         }
 321         if (principal) {
 322                 krb5_principal target_principal;
 323                 ret = krb5_parse_name(gensec_krb5_state->smb_krb5_context->krb5_context, principal,
 324                                       &target_principal);
 325                 if (ret == 0) {
 326                         ret = krb5_mk_req_exact(gensec_krb5_state->smb_krb5_context->krb5_context,
 327                                                 &gensec_krb5_state->auth_context,
 328                                                 gensec_krb5_state->ap_req_options,
 329                                                 target_principal,
 330                                                 &in_data, ccache_container->ccache,
 331                                                 &gensec_krb5_state->enc_ticket);
 332                         krb5_free_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
 333                                             target_principal);
 334                 }
 335         } else {
 336                 ret = krb5_mk_req(gensec_krb5_state->smb_krb5_context->krb5_context,
 337                                   &gensec_krb5_state->auth_context,
 338                                   gensec_krb5_state->ap_req_options,
 339                                   gensec_get_target_service(gensec_security),
 340                                   hostname,
 341                                   &in_data, ccache_container->ccache,
 342                                   &gensec_krb5_state->enc_ticket);
 343         }
 344
 345         smb_krb5_context_remove_event_ctx(gensec_krb5_state->smb_krb5_context, previous_ev, ev);
 346
 347         switch (ret) {
 348         case 0:
 349                 return NT_STATUS_OK;
 350         case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
 351                 DEBUG(3, ("Server [%s] is not registered with our KDC: %s\n",
 352                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 353                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 354         case KRB5_KDC_UNREACH:
 355                 DEBUG(3, ("Cannot reach a KDC we require to contact host [%s]: %s\n",
 356                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 357                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 358         case KRB5KDC_ERR_PREAUTH_FAILED:
 359         case KRB5KRB_AP_ERR_TKT_EXPIRED:
 360         case KRB5_CC_END:
 361                 /* Too much clock skew - we will need to kinit to re-skew the clock */
 362         case KRB5KRB_AP_ERR_SKEW:
 363         case KRB5_KDCREP_SKEW:
 364         {
 365                 DEBUG(3, ("kerberos (mk_req) failed: %s\n",
 366                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 367                 /*fall through*/
 368         }
 369
 370         /* just don't print a message for these really ordinary messages */
 371         case KRB5_FCC_NOFILE:
 372         case KRB5_CC_NOTFOUND:
 373         case ENOENT:
 374
 375                 return NT_STATUS_UNSUCCESSFUL;
 376                 break;
 377
 378         default:
 379                 DEBUG(0, ("kerberos: %s\n",
 380                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 381                 return NT_STATUS_UNSUCCESSFUL;
 382         }
 383 }
 384
 385 static NTSTATUS gensec_krb5_client_start(struct gensec_security *gensec_security)
 386 {
 387         return gensec_krb5_common_client_start(gensec_security, false);
 388 }
 389
 390 static NTSTATUS gensec_fake_gssapi_krb5_client_start(struct gensec_security *gensec_security)
 391 {
 392         return gensec_krb5_common_client_start(gensec_security, true);
 393 }
 394
 395 /**
 396  * Check if the packet is one for this mechansim
 397  *
 398  * @param gensec_security GENSEC state
 399  * @param in The request, as a DATA_BLOB
 400  * @return Error, INVALID_PARAMETER if it's not a packet for us
 401  *                or NT_STATUS_OK if the packet is ok.
 402  */
 403
 404 static NTSTATUS gensec_fake_gssapi_krb5_magic(struct gensec_security *gensec_security,
 405                                   const DATA_BLOB *in)
 406 {
 407         if (gensec_gssapi_check_oid(in, GENSEC_OID_KERBEROS5)) {
 408                 return NT_STATUS_OK;
 409         } else {
 410                 return NT_STATUS_INVALID_PARAMETER;
 411         }
 412 }
 413
 414
 415 /**
 416  * Next state function for the Krb5 GENSEC mechanism
 417  *
 418  * @param gensec_krb5_state KRB5 State
 419  * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
 420  * @param in The request, as a DATA_BLOB
 421  * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
 422  * @return Error, MORE_PROCESSING_REQUIRED if a reply is sent,
 423  *                or NT_STATUS_OK if the user is authenticated.
 424  */
 425
 426 static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 427                                    TALLOC_CTX *out_mem_ctx,
 428                                    struct tevent_context *ev,
 429                                    const DATA_BLOB in, DATA_BLOB *out)
 430 {
 431         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 432         krb5_error_code ret = 0;
 433         NTSTATUS nt_status;
 434
 435         switch (gensec_krb5_state->state_position) {
 436         case GENSEC_KRB5_CLIENT_START:
 437         {
 438                 DATA_BLOB unwrapped_out;
 439
 440                 nt_status = gensec_krb5_common_client_creds(gensec_security, ev, gensec_krb5_state->gssapi);
 441                 if (!NT_STATUS_IS_OK(nt_status)) {
 442                         return nt_status;
 443                 }
 444
 445                 if (gensec_krb5_state->gssapi) {
 446                         unwrapped_out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 447
 448                         /* wrap that up in a nice GSS-API wrapping */
 449                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REQ);
 450                 } else {
 451                         *out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 452                 }
 453                 if (gensec_krb5_state->ap_req_options & AP_OPTS_MUTUAL_REQUIRED) {
 454                         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_MUTUAL_AUTH;
 455                         nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
 456                 } else {
 457                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 458                         nt_status = NT_STATUS_OK;
 459                 }
 460                 return nt_status;
 461         }
 462
 463         case GENSEC_KRB5_CLIENT_MUTUAL_AUTH:
 464         {
 465                 DATA_BLOB unwrapped_in;
 466                 krb5_data inbuf;
 467                 krb5_ap_rep_enc_part *repl = NULL;
 468                 uint8_t tok_id[2];
 469
 470                 if (gensec_krb5_state->gssapi) {
 471                         if (!gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 472                                 DEBUG(1,("gensec_gssapi_parse_krb5_wrap(mutual authentication) failed to parse\n"));
 473                                 dump_data_pw("Mutual authentication message:\n", in.data, in.length);
 474                                 return NT_STATUS_INVALID_PARAMETER;
 475                         }
 476                 } else {
 477                         unwrapped_in = in;
 478                 }
 479                 /* TODO: check the tok_id */
 480
 481                 inbuf.data = unwrapped_in.data;
 482                 inbuf.length = unwrapped_in.length;
 483                 ret = krb5_rd_rep(gensec_krb5_state->smb_krb5_context->krb5_context,
 484                                   gensec_krb5_state->auth_context,
 485                                   &inbuf, &repl);
 486                 if (ret) {
 487                         DEBUG(1,("krb5_rd_rep (mutual authentication) failed (%s)\n",
 488                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, out_mem_ctx)));
 489                         dump_data_pw("Mutual authentication message:\n", (uint8_t *)inbuf.data, inbuf.length);
 490                         nt_status = NT_STATUS_ACCESS_DENIED;
 491                 } else {
 492                         *out = data_blob(NULL, 0);
 493                         nt_status = NT_STATUS_OK;
 494                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 495                 }
 496                 if (repl) {
 497                         krb5_free_ap_rep_enc_part(gensec_krb5_state->smb_krb5_context->krb5_context, repl);
 498                 }
 499                 return nt_status;
 500         }
 501
 502         case GENSEC_KRB5_SERVER_START:
 503         {
 504                 DATA_BLOB unwrapped_in;
 505                 DATA_BLOB unwrapped_out = data_blob(NULL, 0);
 506                 krb5_data inbuf, outbuf;
 507                 uint8_t tok_id[2];
 508                 struct keytab_container *keytab;
 509                 krb5_principal server_in_keytab;
 510                 const char *error_string;
 511                 enum credentials_obtained obtained;
 512
 513                 if (!in.data) {
 514                         return NT_STATUS_INVALID_PARAMETER;
 515                 }
 516
 517                 /* Grab the keytab, however generated */
 518                 ret = cli_credentials_get_keytab(gensec_get_credentials(gensec_security),
 519                                                  gensec_security->settings->lp_ctx, &keytab);
 520                 if (ret) {
 521                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 522                 }
 523
 524                 /* This ensures we lookup the correct entry in that keytab */
 525                 ret = principal_from_credentials(out_mem_ctx, gensec_get_credentials(gensec_security),
 526                                                  gensec_krb5_state->smb_krb5_context,
 527                                                  &server_in_keytab, &obtained, &error_string);
 528
 529                 if (ret) {
 530                         DEBUG(2,("Failed to make credentials from principal: %s\n", error_string));
 531                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 532                 }
 533
 534                 /* Parse the GSSAPI wrapping, if it's there... (win2k3 allows it to be omited) */
 535                 if (gensec_krb5_state->gssapi
 536                     && gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 537                         inbuf.data = unwrapped_in.data;
 538                         inbuf.length = unwrapped_in.length;
 539                 } else {
 540                         inbuf.data = in.data;
 541                         inbuf.length = in.length;
 542                 }
 543
 544                 ret = smb_rd_req_return_stuff(gensec_krb5_state->smb_krb5_context->krb5_context,
 545                                               &gensec_krb5_state->auth_context,
 546                                               &inbuf, keytab->keytab, server_in_keytab,
 547                                               &outbuf,
 548                                               &gensec_krb5_state->ticket,
 549                                               &gensec_krb5_state->keyblock);
 550
 551                 if (ret) {
 552                         return NT_STATUS_LOGON_FAILURE;
 553                 }
 554                 unwrapped_out.data = (uint8_t *)outbuf.data;
 555                 unwrapped_out.length = outbuf.length;
 556                 gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 557                 /* wrap that up in a nice GSS-API wrapping */
 558                 if (gensec_krb5_state->gssapi) {
 559                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REP);
 560                 } else {
 561                         *out = data_blob_talloc(out_mem_ctx, outbuf.data, outbuf.length);
 562                 }
 563                 krb5_data_free(&outbuf);
 564                 return NT_STATUS_OK;
 565         }
 566
 567         case GENSEC_KRB5_DONE:
 568         default:
 569                 /* Asking too many times... */
 570                 return NT_STATUS_INVALID_PARAMETER;
 571         }
 572 }
 573
 574 static NTSTATUS gensec_krb5_session_key(struct gensec_security *gensec_security,
 575                                         TALLOC_CTX *mem_ctx,
 576                                         DATA_BLOB *session_key)
 577 {
 578         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 579         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 580         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 581         krb5_keyblock *skey;
 582         krb5_error_code err = -1;
 583
 584         if (gensec_krb5_state->state_position != GENSEC_KRB5_DONE) {
 585                 return NT_STATUS_NO_USER_SESSION_KEY;
 586         }
 587
 588         switch (gensec_security->gensec_role) {
 589         case GENSEC_CLIENT:
 590                 err = krb5_auth_con_getlocalsubkey(context, auth_context, &skey);
 591                 break;
 592         case GENSEC_SERVER:
 593                 err = krb5_auth_con_getremotesubkey(context, auth_context, &skey);
 594                 break;
 595         }
 596         if (err == 0 && skey != NULL) {
 597                 DEBUG(10, ("Got KRB5 session key of length %d\n",
 598                            (int)KRB5_KEY_LENGTH(skey)));
 599                 *session_key = data_blob_talloc(mem_ctx,
 600                                                KRB5_KEY_DATA(skey), KRB5_KEY_LENGTH(skey));
 601                 dump_data_pw("KRB5 Session Key:\n", session_key->data, session_key->length);
 602
 603                 krb5_free_keyblock(context, skey);
 604                 return NT_STATUS_OK;
 605         } else {
 606                 DEBUG(10, ("KRB5 error getting session key %d\n", err));
 607                 return NT_STATUS_NO_USER_SESSION_KEY;
 608         }
 609 }
 610
 611 static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security,
 612                                          TALLOC_CTX *mem_ctx_out,
 613                                          struct auth_session_info **_session_info)
 614 {
 615         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 616         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 617         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 618         struct auth_user_info_dc *user_info_dc = NULL;
 619         struct auth_session_info *session_info = NULL;
 620         struct PAC_LOGON_INFO *logon_info;
 621
 622         krb5_principal client_principal;
 623         char *principal_string;
 624
 625         DATA_BLOB pac;
 626         krb5_data pac_data;
 627
 628         krb5_error_code ret;
 629
 630         TALLOC_CTX *mem_ctx = talloc_new(mem_ctx_out);
 631         if (!mem_ctx) {
 632                 return NT_STATUS_NO_MEMORY;
 633         }
 634
 635         ret = krb5_ticket_get_client(context, gensec_krb5_state->ticket, &client_principal);
 636         if (ret) {
 637                 DEBUG(5, ("krb5_ticket_get_client failed to get cleint principal: %s\n",
 638                           smb_get_krb5_error_message(context,
 639                                                      ret, mem_ctx)));
 640                 talloc_free(mem_ctx);
 641                 return NT_STATUS_NO_MEMORY;
 642         }
 643
 644         ret = krb5_unparse_name(gensec_krb5_state->smb_krb5_context->krb5_context,
 645                                 client_principal, &principal_string);
 646         if (ret) {
 647                 DEBUG(1, ("Unable to parse client principal: %s\n",
 648                           smb_get_krb5_error_message(context,
 649                                                      ret, mem_ctx)));
 650                 krb5_free_principal(context, client_principal);
 651                 talloc_free(mem_ctx);
 652                 return NT_STATUS_NO_MEMORY;
 653         }
 654
 655         ret = krb5_ticket_get_authorization_data_type(context, gensec_krb5_state->ticket,
 656                                                       KRB5_AUTHDATA_WIN2K_PAC,
 657                                                       &pac_data);
 658
 659         if (ret && gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
 660                 DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access: %s \n",
 661                           principal_string,
 662                           smb_get_krb5_error_message(context,
 663                                                      ret, mem_ctx)));
 664                 free(principal_string);
 665                 krb5_free_principal(context, client_principal);
 666                 talloc_free(mem_ctx);
 667                 return NT_STATUS_ACCESS_DENIED;
 668         } else if (ret) {
 669                 /* NO pac */
 670                 DEBUG(5, ("krb5_ticket_get_authorization_data_type failed to find PAC: %s\n",
 671                           smb_get_krb5_error_message(context,
 672                                                      ret, mem_ctx)));
 673                 if (gensec_security->auth_context &&
 674                     !gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
 675                         DEBUG(1, ("Unable to find PAC for %s, resorting to local user lookup: %s",
 676                                   principal_string, smb_get_krb5_error_message(context,
 677                                                      ret, mem_ctx)));
 678                         nt_status = gensec_security->auth_context->get_user_info_dc_principal(mem_ctx,
 679                                                                                              gensec_security->auth_context,
 680                                                                                              principal_string,
 681                                                                                              NULL, &user_info_dc);
 682                         if (!NT_STATUS_IS_OK(nt_status)) {
 683                                 free(principal_string);
 684                                 krb5_free_principal(context, client_principal);
 685                                 talloc_free(mem_ctx);
 686                                 return nt_status;
 687                         }
 688                 } else {
 689                         DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access\n",
 690                                   principal_string));
 691                         free(principal_string);
 692                         krb5_free_principal(context, client_principal);
 693                         talloc_free(mem_ctx);
 694                         return NT_STATUS_ACCESS_DENIED;
 695                 }
 696         } else {
 697                 /* Found pac */
 698                 union netr_Validation validation;
 699
 700                 pac = data_blob_talloc(mem_ctx, pac_data.data, pac_data.length);
 701                 if (!pac.data) {
 702                         free(principal_string);
 703                         krb5_free_principal(context, client_principal);
 704                         talloc_free(mem_ctx);
 705                         return NT_STATUS_NO_MEMORY;
 706                 }
 707
 708                 /* decode and verify the pac */
 709                 nt_status = kerberos_pac_logon_info(gensec_krb5_state,
 710                                                     pac,
 711                                                     gensec_krb5_state->smb_krb5_context->krb5_context,
 712                                                     NULL, gensec_krb5_state->keyblock,
 713                                                     client_principal,
 714                                                     gensec_krb5_state->ticket->ticket.authtime, &logon_info);
 715
 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                 validation.sam3 = &logon_info->info3;
 724                 nt_status = make_user_info_dc_netlogon_validation(mem_ctx,
 725                                                                  NULL,
 726                                                                  3, &validation,
 727                                                                   true, /* This user was authenticated */
 728                                                                  &user_info_dc);
 729                 if (!NT_STATUS_IS_OK(nt_status)) {
 730                         free(principal_string);
 731                         krb5_free_principal(context, client_principal);
 732                         talloc_free(mem_ctx);
 733                         return nt_status;
 734                 }
 735         }
 736
 737         free(principal_string);
 738         krb5_free_principal(context, client_principal);
 739
 740         /* references the user_info_dc into the session_info */
 741         nt_status = gensec_generate_session_info(mem_ctx, gensec_security, user_info_dc, &session_info);
 742
 743         if (!NT_STATUS_IS_OK(nt_status)) {
 744                 talloc_free(mem_ctx);
 745                 return nt_status;
 746         }
 747
 748         nt_status = gensec_krb5_session_key(gensec_security, session_info, &session_info->session_key);
 749
 750         if (!NT_STATUS_IS_OK(nt_status)) {
 751                 talloc_free(mem_ctx);
 752                 return nt_status;
 753         }
 754
 755         *_session_info = talloc_steal(mem_ctx_out, session_info);
 756
 757         talloc_free(mem_ctx);
 758         return NT_STATUS_OK;
 759 }
 760
 761 static NTSTATUS gensec_krb5_wrap(struct gensec_security *gensec_security,
 762                                    TALLOC_CTX *mem_ctx,
 763                                    const DATA_BLOB *in,
 764                                    DATA_BLOB *out)
 765 {
 766         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 767         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 768         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 769         krb5_error_code ret;
 770         krb5_data input, output;
 771         input.length = in->length;
 772         input.data = in->data;
 773
 774         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 775                 ret = krb5_mk_priv(context, auth_context, &input, &output, NULL);
 776                 if (ret) {
 777                         DEBUG(1, ("krb5_mk_priv failed: %s\n",
 778                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 779                                                              ret, mem_ctx)));
 780                         return NT_STATUS_ACCESS_DENIED;
 781                 }
 782                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 783
 784                 krb5_data_free(&output);
 785         } else {
 786                 return NT_STATUS_ACCESS_DENIED;
 787         }
 788         return NT_STATUS_OK;
 789 }
 790
 791 static NTSTATUS gensec_krb5_unwrap(struct gensec_security *gensec_security,
 792                                      TALLOC_CTX *mem_ctx,
 793                                      const DATA_BLOB *in,
 794                                      DATA_BLOB *out)
 795 {
 796         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 797         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 798         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 799         krb5_error_code ret;
 800         krb5_data input, output;
 801         krb5_replay_data replay;
 802         input.length = in->length;
 803         input.data = in->data;
 804
 805         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 806                 ret = krb5_rd_priv(context, auth_context, &input, &output, &replay);
 807                 if (ret) {
 808                         DEBUG(1, ("krb5_rd_priv failed: %s\n",
 809                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 810                                                              ret, mem_ctx)));
 811                         return NT_STATUS_ACCESS_DENIED;
 812                 }
 813                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 814
 815                 krb5_data_free(&output);
 816         } else {
 817                 return NT_STATUS_ACCESS_DENIED;
 818         }
 819         return NT_STATUS_OK;
 820 }
 821
 822 static bool gensec_krb5_have_feature(struct gensec_security *gensec_security,
 823                                      uint32_t feature)
 824 {
 825         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 826         if (feature & GENSEC_FEATURE_SESSION_KEY) {
 827                 return true;
 828         }
 829         if (!gensec_krb5_state->gssapi &&
 830             (feature & GENSEC_FEATURE_SEAL)) {
 831                 return true;
 832         }
 833
 834         return false;
 835 }
 836
 837 static const char *gensec_krb5_oids[] = {
 838         GENSEC_OID_KERBEROS5,
 839         GENSEC_OID_KERBEROS5_OLD,
 840         NULL
 841 };
 842
 843 static const struct gensec_security_ops gensec_fake_gssapi_krb5_security_ops = {
 844         .name           = "fake_gssapi_krb5",
 845         .auth_type      = DCERPC_AUTH_TYPE_KRB5,
 846         .oid            = gensec_krb5_oids,
 847         .client_start   = gensec_fake_gssapi_krb5_client_start,
 848         .server_start   = gensec_fake_gssapi_krb5_server_start,
 849         .update         = gensec_krb5_update,
 850         .magic          = gensec_fake_gssapi_krb5_magic,
 851         .session_key    = gensec_krb5_session_key,
 852         .session_info   = gensec_krb5_session_info,
 853         .have_feature   = gensec_krb5_have_feature,
 854         .enabled        = false,
 855         .kerberos       = true,
 856         .priority       = GENSEC_KRB5
 857 };
 858
 859 static const struct gensec_security_ops gensec_krb5_security_ops = {
 860         .name           = "krb5",
 861         .client_start   = gensec_krb5_client_start,
 862         .server_start   = gensec_krb5_server_start,
 863         .update         = gensec_krb5_update,
 864         .session_key    = gensec_krb5_session_key,
 865         .session_info   = gensec_krb5_session_info,
 866         .have_feature   = gensec_krb5_have_feature,
 867         .wrap           = gensec_krb5_wrap,
 868         .unwrap         = gensec_krb5_unwrap,
 869         .enabled        = true,
 870         .kerberos       = true,
 871         .priority       = GENSEC_KRB5
 872 };
 873
 874 _PUBLIC_ NTSTATUS gensec_krb5_init(void)
 875 {
 876         NTSTATUS ret;
 877
 878         ret = gensec_register(&gensec_krb5_security_ops);
 879         if (!NT_STATUS_IS_OK(ret)) {
 880                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 881                         gensec_krb5_security_ops.name));
 882                 return ret;
 883         }
 884
 885         ret = gensec_register(&gensec_fake_gssapi_krb5_security_ops);
 886         if (!NT_STATUS_IS_OK(ret)) {
 887                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 888                         gensec_krb5_security_ops.name));
 889                 return ret;
 890         }
 891
 892         return ret;
 893 }