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, bool gssapi)
 276 {
 277         struct gensec_krb5_state *gensec_krb5_state;
 278         krb5_error_code ret;
 279         struct ccache_container *ccache_container;
 280         const char *error_string;
 281         const char *principal;
 282         const char *hostname;
 283         krb5_data in_data;
 284         struct tevent_context *previous_ev;
 285
 286         gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 287
 288         principal = gensec_get_target_principal(gensec_security);
 289         hostname = gensec_get_target_hostname(gensec_security);
 290
 291         ret = cli_credentials_get_ccache(gensec_get_credentials(gensec_security),
 292                                          gensec_security->event_ctx,
 293                                          gensec_security->settings->lp_ctx, &ccache_container, &error_string);
 294         switch (ret) {
 295         case 0:
 296                 break;
 297         case KRB5KDC_ERR_PREAUTH_FAILED:
 298         case KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN:
 299                 return NT_STATUS_LOGON_FAILURE;
 300         case KRB5_KDC_UNREACH:
 301                 DEBUG(3, ("Cannot reach a KDC we require to contact %s: %s\n", principal, error_string));
 302                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 303         case KRB5_CC_NOTFOUND:
 304         case KRB5_CC_END:
 305                 DEBUG(3, ("Error preparing credentials we require to contact %s : %s\n", principal, error_string));
 306                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 307         default:
 308                 DEBUG(1, ("gensec_krb5_start: Aquiring initiator credentials failed: %s\n", error_string));
 309                 return NT_STATUS_UNSUCCESSFUL;
 310         }
 311         in_data.length = 0;
 312
 313         /* Do this every time, in case we have weird recursive issues here */
 314         ret = smb_krb5_context_set_event_ctx(gensec_krb5_state->smb_krb5_context, gensec_security->event_ctx, &previous_ev);
 315         if (ret != 0) {
 316                 DEBUG(1, ("gensec_krb5_start: Setting event context failed\n"));
 317                 return NT_STATUS_NO_MEMORY;
 318         }
 319         if (principal) {
 320                 krb5_principal target_principal;
 321                 ret = krb5_parse_name(gensec_krb5_state->smb_krb5_context->krb5_context, principal,
 322                                       &target_principal);
 323                 if (ret == 0) {
 324                         ret = krb5_mk_req_exact(gensec_krb5_state->smb_krb5_context->krb5_context,
 325                                                 &gensec_krb5_state->auth_context,
 326                                                 gensec_krb5_state->ap_req_options,
 327                                                 target_principal,
 328                                                 &in_data, ccache_container->ccache,
 329                                                 &gensec_krb5_state->enc_ticket);
 330                         krb5_free_principal(gensec_krb5_state->smb_krb5_context->krb5_context,
 331                                             target_principal);
 332                 }
 333         } else {
 334                 ret = krb5_mk_req(gensec_krb5_state->smb_krb5_context->krb5_context,
 335                                   &gensec_krb5_state->auth_context,
 336                                   gensec_krb5_state->ap_req_options,
 337                                   gensec_get_target_service(gensec_security),
 338                                   hostname,
 339                                   &in_data, ccache_container->ccache,
 340                                   &gensec_krb5_state->enc_ticket);
 341         }
 342
 343         smb_krb5_context_remove_event_ctx(gensec_krb5_state->smb_krb5_context, previous_ev, gensec_security->event_ctx);
 344
 345         switch (ret) {
 346         case 0:
 347                 return NT_STATUS_OK;
 348         case KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN:
 349                 DEBUG(3, ("Server [%s] is not registered with our KDC: %s\n",
 350                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 351                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 352         case KRB5_KDC_UNREACH:
 353                 DEBUG(3, ("Cannot reach a KDC we require to contact host [%s]: %s\n",
 354                           hostname, smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 355                 return NT_STATUS_INVALID_PARAMETER; /* Make SPNEGO ignore us, we can't go any further here */
 356         case KRB5KDC_ERR_PREAUTH_FAILED:
 357         case KRB5KRB_AP_ERR_TKT_EXPIRED:
 358         case KRB5_CC_END:
 359                 /* Too much clock skew - we will need to kinit to re-skew the clock */
 360         case KRB5KRB_AP_ERR_SKEW:
 361         case KRB5_KDCREP_SKEW:
 362         {
 363                 DEBUG(3, ("kerberos (mk_req) failed: %s\n",
 364                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 365                 /*fall through*/
 366         }
 367
 368         /* just don't print a message for these really ordinary messages */
 369         case KRB5_FCC_NOFILE:
 370         case KRB5_CC_NOTFOUND:
 371         case ENOENT:
 372
 373                 return NT_STATUS_UNSUCCESSFUL;
 374                 break;
 375
 376         default:
 377                 DEBUG(0, ("kerberos: %s\n",
 378                           smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, gensec_krb5_state)));
 379                 return NT_STATUS_UNSUCCESSFUL;
 380         }
 381 }
 382
 383 static NTSTATUS gensec_krb5_client_start(struct gensec_security *gensec_security)
 384 {
 385         return gensec_krb5_common_client_start(gensec_security, false);
 386 }
 387
 388 static NTSTATUS gensec_fake_gssapi_krb5_client_start(struct gensec_security *gensec_security)
 389 {
 390         return gensec_krb5_common_client_start(gensec_security, true);
 391 }
 392
 393 /**
 394  * Check if the packet is one for this mechansim
 395  *
 396  * @param gensec_security GENSEC state
 397  * @param in The request, as a DATA_BLOB
 398  * @return Error, INVALID_PARAMETER if it's not a packet for us
 399  *                or NT_STATUS_OK if the packet is ok.
 400  */
 401
 402 static NTSTATUS gensec_fake_gssapi_krb5_magic(struct gensec_security *gensec_security,
 403                                   const DATA_BLOB *in)
 404 {
 405         if (gensec_gssapi_check_oid(in, GENSEC_OID_KERBEROS5)) {
 406                 return NT_STATUS_OK;
 407         } else {
 408                 return NT_STATUS_INVALID_PARAMETER;
 409         }
 410 }
 411
 412
 413 /**
 414  * Next state function for the Krb5 GENSEC mechanism
 415  *
 416  * @param gensec_krb5_state KRB5 State
 417  * @param out_mem_ctx The TALLOC_CTX for *out to be allocated on
 418  * @param in The request, as a DATA_BLOB
 419  * @param out The reply, as an talloc()ed DATA_BLOB, on *out_mem_ctx
 420  * @return Error, MORE_PROCESSING_REQUIRED if a reply is sent,
 421  *                or NT_STATUS_OK if the user is authenticated.
 422  */
 423
 424 static NTSTATUS gensec_krb5_update(struct gensec_security *gensec_security,
 425                                    TALLOC_CTX *out_mem_ctx,
 426                                    const DATA_BLOB in, DATA_BLOB *out)
 427 {
 428         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 429         krb5_error_code ret = 0;
 430         NTSTATUS nt_status;
 431
 432         switch (gensec_krb5_state->state_position) {
 433         case GENSEC_KRB5_CLIENT_START:
 434         {
 435                 DATA_BLOB unwrapped_out;
 436
 437                 nt_status = gensec_krb5_common_client_creds(gensec_security, gensec_krb5_state->gssapi);
 438                 if (!NT_STATUS_IS_OK(nt_status)) {
 439                         return nt_status;
 440                 }
 441
 442                 if (gensec_krb5_state->gssapi) {
 443                         unwrapped_out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 444
 445                         /* wrap that up in a nice GSS-API wrapping */
 446                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REQ);
 447                 } else {
 448                         *out = data_blob_talloc(out_mem_ctx, gensec_krb5_state->enc_ticket.data, gensec_krb5_state->enc_ticket.length);
 449                 }
 450                 if (gensec_krb5_state->ap_req_options & AP_OPTS_MUTUAL_REQUIRED) {
 451                         gensec_krb5_state->state_position = GENSEC_KRB5_CLIENT_MUTUAL_AUTH;
 452                         nt_status = NT_STATUS_MORE_PROCESSING_REQUIRED;
 453                 } else {
 454                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 455                         nt_status = NT_STATUS_OK;
 456                 }
 457                 return nt_status;
 458         }
 459
 460         case GENSEC_KRB5_CLIENT_MUTUAL_AUTH:
 461         {
 462                 DATA_BLOB unwrapped_in;
 463                 krb5_data inbuf;
 464                 krb5_ap_rep_enc_part *repl = NULL;
 465                 uint8_t tok_id[2];
 466
 467                 if (gensec_krb5_state->gssapi) {
 468                         if (!gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 469                                 DEBUG(1,("gensec_gssapi_parse_krb5_wrap(mutual authentication) failed to parse\n"));
 470                                 dump_data_pw("Mutual authentication message:\n", in.data, in.length);
 471                                 return NT_STATUS_INVALID_PARAMETER;
 472                         }
 473                 } else {
 474                         unwrapped_in = in;
 475                 }
 476                 /* TODO: check the tok_id */
 477
 478                 inbuf.data = unwrapped_in.data;
 479                 inbuf.length = unwrapped_in.length;
 480                 ret = krb5_rd_rep(gensec_krb5_state->smb_krb5_context->krb5_context,
 481                                   gensec_krb5_state->auth_context,
 482                                   &inbuf, &repl);
 483                 if (ret) {
 484                         DEBUG(1,("krb5_rd_rep (mutual authentication) failed (%s)\n",
 485                                  smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context, ret, out_mem_ctx)));
 486                         dump_data_pw("Mutual authentication message:\n", (uint8_t *)inbuf.data, inbuf.length);
 487                         nt_status = NT_STATUS_ACCESS_DENIED;
 488                 } else {
 489                         *out = data_blob(NULL, 0);
 490                         nt_status = NT_STATUS_OK;
 491                         gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 492                 }
 493                 if (repl) {
 494                         krb5_free_ap_rep_enc_part(gensec_krb5_state->smb_krb5_context->krb5_context, repl);
 495                 }
 496                 return nt_status;
 497         }
 498
 499         case GENSEC_KRB5_SERVER_START:
 500         {
 501                 DATA_BLOB unwrapped_in;
 502                 DATA_BLOB unwrapped_out = data_blob(NULL, 0);
 503                 krb5_data inbuf, outbuf;
 504                 uint8_t tok_id[2];
 505                 struct keytab_container *keytab;
 506                 krb5_principal server_in_keytab;
 507                 const char *error_string;
 508                 enum credentials_obtained obtained;
 509
 510                 if (!in.data) {
 511                         return NT_STATUS_INVALID_PARAMETER;
 512                 }
 513
 514                 /* Grab the keytab, however generated */
 515                 ret = cli_credentials_get_keytab(gensec_get_credentials(gensec_security),
 516                                                  gensec_security->settings->lp_ctx, &keytab);
 517                 if (ret) {
 518                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 519                 }
 520
 521                 /* This ensures we lookup the correct entry in that keytab */
 522                 ret = principal_from_credentials(out_mem_ctx, gensec_get_credentials(gensec_security),
 523                                                  gensec_krb5_state->smb_krb5_context,
 524                                                  &server_in_keytab, &obtained, &error_string);
 525
 526                 if (ret) {
 527                         DEBUG(2,("Failed to make credentials from principal: %s\n", error_string));
 528                         return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;
 529                 }
 530
 531                 /* Parse the GSSAPI wrapping, if it's there... (win2k3 allows it to be omited) */
 532                 if (gensec_krb5_state->gssapi
 533                     && gensec_gssapi_parse_krb5_wrap(out_mem_ctx, &in, &unwrapped_in, tok_id)) {
 534                         inbuf.data = unwrapped_in.data;
 535                         inbuf.length = unwrapped_in.length;
 536                 } else {
 537                         inbuf.data = in.data;
 538                         inbuf.length = in.length;
 539                 }
 540
 541                 ret = smb_rd_req_return_stuff(gensec_krb5_state->smb_krb5_context->krb5_context,
 542                                               &gensec_krb5_state->auth_context,
 543                                               &inbuf, keytab->keytab, server_in_keytab,
 544                                               &outbuf,
 545                                               &gensec_krb5_state->ticket,
 546                                               &gensec_krb5_state->keyblock);
 547
 548                 if (ret) {
 549                         return NT_STATUS_LOGON_FAILURE;
 550                 }
 551                 unwrapped_out.data = (uint8_t *)outbuf.data;
 552                 unwrapped_out.length = outbuf.length;
 553                 gensec_krb5_state->state_position = GENSEC_KRB5_DONE;
 554                 /* wrap that up in a nice GSS-API wrapping */
 555                 if (gensec_krb5_state->gssapi) {
 556                         *out = gensec_gssapi_gen_krb5_wrap(out_mem_ctx, &unwrapped_out, TOK_ID_KRB_AP_REP);
 557                 } else {
 558                         *out = data_blob_talloc(out_mem_ctx, outbuf.data, outbuf.length);
 559                 }
 560                 krb5_data_free(&outbuf);
 561                 return NT_STATUS_OK;
 562         }
 563
 564         case GENSEC_KRB5_DONE:
 565         default:
 566                 /* Asking too many times... */
 567                 return NT_STATUS_INVALID_PARAMETER;
 568         }
 569 }
 570
 571 static NTSTATUS gensec_krb5_session_key(struct gensec_security *gensec_security,
 572                                         TALLOC_CTX *mem_ctx,
 573                                         DATA_BLOB *session_key)
 574 {
 575         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 576         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 577         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 578         krb5_keyblock *skey;
 579         krb5_error_code err = -1;
 580
 581         if (gensec_krb5_state->state_position != GENSEC_KRB5_DONE) {
 582                 return NT_STATUS_NO_USER_SESSION_KEY;
 583         }
 584
 585         switch (gensec_security->gensec_role) {
 586         case GENSEC_CLIENT:
 587                 err = krb5_auth_con_getlocalsubkey(context, auth_context, &skey);
 588                 break;
 589         case GENSEC_SERVER:
 590                 err = krb5_auth_con_getremotesubkey(context, auth_context, &skey);
 591                 break;
 592         }
 593         if (err == 0 && skey != NULL) {
 594                 DEBUG(10, ("Got KRB5 session key of length %d\n",
 595                            (int)KRB5_KEY_LENGTH(skey)));
 596                 *session_key = data_blob_talloc(mem_ctx,
 597                                                KRB5_KEY_DATA(skey), KRB5_KEY_LENGTH(skey));
 598                 dump_data_pw("KRB5 Session Key:\n", session_key->data, session_key->length);
 599
 600                 krb5_free_keyblock(context, skey);
 601                 return NT_STATUS_OK;
 602         } else {
 603                 DEBUG(10, ("KRB5 error getting session key %d\n", err));
 604                 return NT_STATUS_NO_USER_SESSION_KEY;
 605         }
 606 }
 607
 608 static NTSTATUS gensec_krb5_session_info(struct gensec_security *gensec_security,
 609                                          TALLOC_CTX *mem_ctx_out,
 610                                          struct auth_session_info **_session_info)
 611 {
 612         NTSTATUS nt_status = NT_STATUS_UNSUCCESSFUL;
 613         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 614         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 615         struct auth_user_info_dc *user_info_dc = NULL;
 616         struct auth_session_info *session_info = NULL;
 617         struct PAC_LOGON_INFO *logon_info;
 618
 619         krb5_principal client_principal;
 620         char *principal_string;
 621
 622         DATA_BLOB pac;
 623         krb5_data pac_data;
 624
 625         krb5_error_code ret;
 626
 627         TALLOC_CTX *mem_ctx = talloc_new(mem_ctx_out);
 628         if (!mem_ctx) {
 629                 return NT_STATUS_NO_MEMORY;
 630         }
 631
 632         ret = krb5_ticket_get_client(context, gensec_krb5_state->ticket, &client_principal);
 633         if (ret) {
 634                 DEBUG(5, ("krb5_ticket_get_client failed to get cleint principal: %s\n",
 635                           smb_get_krb5_error_message(context,
 636                                                      ret, mem_ctx)));
 637                 talloc_free(mem_ctx);
 638                 return NT_STATUS_NO_MEMORY;
 639         }
 640
 641         ret = krb5_unparse_name(gensec_krb5_state->smb_krb5_context->krb5_context,
 642                                 client_principal, &principal_string);
 643         if (ret) {
 644                 DEBUG(1, ("Unable to parse client principal: %s\n",
 645                           smb_get_krb5_error_message(context,
 646                                                      ret, mem_ctx)));
 647                 krb5_free_principal(context, client_principal);
 648                 talloc_free(mem_ctx);
 649                 return NT_STATUS_NO_MEMORY;
 650         }
 651
 652         ret = krb5_ticket_get_authorization_data_type(context, gensec_krb5_state->ticket,
 653                                                       KRB5_AUTHDATA_WIN2K_PAC,
 654                                                       &pac_data);
 655
 656         if (ret && gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
 657                 DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access: %s \n",
 658                           principal_string,
 659                           smb_get_krb5_error_message(context,
 660                                                      ret, mem_ctx)));
 661                 free(principal_string);
 662                 krb5_free_principal(context, client_principal);
 663                 talloc_free(mem_ctx);
 664                 return NT_STATUS_ACCESS_DENIED;
 665         } else if (ret) {
 666                 /* NO pac */
 667                 DEBUG(5, ("krb5_ticket_get_authorization_data_type failed to find PAC: %s\n",
 668                           smb_get_krb5_error_message(context,
 669                                                      ret, mem_ctx)));
 670                 if (gensec_security->auth_context &&
 671                     !gensec_setting_bool(gensec_security->settings, "gensec", "require_pac", false)) {
 672                         DEBUG(1, ("Unable to find PAC for %s, resorting to local user lookup: %s",
 673                                   principal_string, smb_get_krb5_error_message(context,
 674                                                      ret, mem_ctx)));
 675                         nt_status = gensec_security->auth_context->get_user_info_dc_principal(mem_ctx,
 676                                                                                              gensec_security->auth_context,
 677                                                                                              principal_string,
 678                                                                                              NULL, &user_info_dc);
 679                         if (!NT_STATUS_IS_OK(nt_status)) {
 680                                 free(principal_string);
 681                                 krb5_free_principal(context, client_principal);
 682                                 talloc_free(mem_ctx);
 683                                 return nt_status;
 684                         }
 685                 } else {
 686                         DEBUG(1, ("Unable to find PAC in ticket from %s, failing to allow access\n",
 687                                   principal_string));
 688                         free(principal_string);
 689                         krb5_free_principal(context, client_principal);
 690                         talloc_free(mem_ctx);
 691                         return NT_STATUS_ACCESS_DENIED;
 692                 }
 693         } else {
 694                 /* Found pac */
 695                 union netr_Validation validation;
 696
 697                 pac = data_blob_talloc(mem_ctx, pac_data.data, pac_data.length);
 698                 if (!pac.data) {
 699                         free(principal_string);
 700                         krb5_free_principal(context, client_principal);
 701                         talloc_free(mem_ctx);
 702                         return NT_STATUS_NO_MEMORY;
 703                 }
 704
 705                 /* decode and verify the pac */
 706                 nt_status = kerberos_pac_logon_info(gensec_krb5_state,
 707                                                     pac,
 708                                                     gensec_krb5_state->smb_krb5_context->krb5_context,
 709                                                     NULL, gensec_krb5_state->keyblock,
 710                                                     client_principal,
 711                                                     gensec_krb5_state->ticket->ticket.authtime, &logon_info);
 712
 713                 if (!NT_STATUS_IS_OK(nt_status)) {
 714                         free(principal_string);
 715                         krb5_free_principal(context, client_principal);
 716                         talloc_free(mem_ctx);
 717                         return nt_status;
 718                 }
 719
 720                 validation.sam3 = &logon_info->info3;
 721                 nt_status = make_user_info_dc_netlogon_validation(mem_ctx,
 722                                                                  NULL,
 723                                                                  3, &validation,
 724                                                                   true, /* This user was authenticated */
 725                                                                  &user_info_dc);
 726                 if (!NT_STATUS_IS_OK(nt_status)) {
 727                         free(principal_string);
 728                         krb5_free_principal(context, client_principal);
 729                         talloc_free(mem_ctx);
 730                         return nt_status;
 731                 }
 732         }
 733
 734         free(principal_string);
 735         krb5_free_principal(context, client_principal);
 736
 737         /* references the user_info_dc into the session_info */
 738         nt_status = gensec_generate_session_info(mem_ctx, gensec_security, user_info_dc, &session_info);
 739
 740         if (!NT_STATUS_IS_OK(nt_status)) {
 741                 talloc_free(mem_ctx);
 742                 return nt_status;
 743         }
 744
 745         nt_status = gensec_krb5_session_key(gensec_security, session_info, &session_info->session_key);
 746
 747         if (!NT_STATUS_IS_OK(nt_status)) {
 748                 talloc_free(mem_ctx);
 749                 return nt_status;
 750         }
 751
 752         *_session_info = talloc_steal(mem_ctx_out, session_info);
 753
 754         talloc_free(mem_ctx);
 755         return NT_STATUS_OK;
 756 }
 757
 758 static NTSTATUS gensec_krb5_wrap(struct gensec_security *gensec_security,
 759                                    TALLOC_CTX *mem_ctx,
 760                                    const DATA_BLOB *in,
 761                                    DATA_BLOB *out)
 762 {
 763         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 764         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 765         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 766         krb5_error_code ret;
 767         krb5_data input, output;
 768         input.length = in->length;
 769         input.data = in->data;
 770
 771         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 772                 ret = krb5_mk_priv(context, auth_context, &input, &output, NULL);
 773                 if (ret) {
 774                         DEBUG(1, ("krb5_mk_priv failed: %s\n",
 775                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 776                                                              ret, mem_ctx)));
 777                         return NT_STATUS_ACCESS_DENIED;
 778                 }
 779                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 780
 781                 krb5_data_free(&output);
 782         } else {
 783                 return NT_STATUS_ACCESS_DENIED;
 784         }
 785         return NT_STATUS_OK;
 786 }
 787
 788 static NTSTATUS gensec_krb5_unwrap(struct gensec_security *gensec_security,
 789                                      TALLOC_CTX *mem_ctx,
 790                                      const DATA_BLOB *in,
 791                                      DATA_BLOB *out)
 792 {
 793         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 794         krb5_context context = gensec_krb5_state->smb_krb5_context->krb5_context;
 795         krb5_auth_context auth_context = gensec_krb5_state->auth_context;
 796         krb5_error_code ret;
 797         krb5_data input, output;
 798         krb5_replay_data replay;
 799         input.length = in->length;
 800         input.data = in->data;
 801
 802         if (gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL)) {
 803                 ret = krb5_rd_priv(context, auth_context, &input, &output, &replay);
 804                 if (ret) {
 805                         DEBUG(1, ("krb5_rd_priv failed: %s\n",
 806                                   smb_get_krb5_error_message(gensec_krb5_state->smb_krb5_context->krb5_context,
 807                                                              ret, mem_ctx)));
 808                         return NT_STATUS_ACCESS_DENIED;
 809                 }
 810                 *out = data_blob_talloc(mem_ctx, output.data, output.length);
 811
 812                 krb5_data_free(&output);
 813         } else {
 814                 return NT_STATUS_ACCESS_DENIED;
 815         }
 816         return NT_STATUS_OK;
 817 }
 818
 819 static bool gensec_krb5_have_feature(struct gensec_security *gensec_security,
 820                                      uint32_t feature)
 821 {
 822         struct gensec_krb5_state *gensec_krb5_state = (struct gensec_krb5_state *)gensec_security->private_data;
 823         if (feature & GENSEC_FEATURE_SESSION_KEY) {
 824                 return true;
 825         }
 826         if (!gensec_krb5_state->gssapi &&
 827             (feature & GENSEC_FEATURE_SEAL)) {
 828                 return true;
 829         }
 830
 831         return false;
 832 }
 833
 834 static const char *gensec_krb5_oids[] = {
 835         GENSEC_OID_KERBEROS5,
 836         GENSEC_OID_KERBEROS5_OLD,
 837         NULL
 838 };
 839
 840 static const struct gensec_security_ops gensec_fake_gssapi_krb5_security_ops = {
 841         .name           = "fake_gssapi_krb5",
 842         .auth_type      = DCERPC_AUTH_TYPE_KRB5,
 843         .oid            = gensec_krb5_oids,
 844         .client_start   = gensec_fake_gssapi_krb5_client_start,
 845         .server_start   = gensec_fake_gssapi_krb5_server_start,
 846         .update         = gensec_krb5_update,
 847         .magic          = gensec_fake_gssapi_krb5_magic,
 848         .session_key    = gensec_krb5_session_key,
 849         .session_info   = gensec_krb5_session_info,
 850         .have_feature   = gensec_krb5_have_feature,
 851         .enabled        = false,
 852         .kerberos       = true,
 853         .priority       = GENSEC_KRB5
 854 };
 855
 856 static const struct gensec_security_ops gensec_krb5_security_ops = {
 857         .name           = "krb5",
 858         .client_start   = gensec_krb5_client_start,
 859         .server_start   = gensec_krb5_server_start,
 860         .update         = gensec_krb5_update,
 861         .session_key    = gensec_krb5_session_key,
 862         .session_info   = gensec_krb5_session_info,
 863         .have_feature   = gensec_krb5_have_feature,
 864         .wrap           = gensec_krb5_wrap,
 865         .unwrap         = gensec_krb5_unwrap,
 866         .enabled        = true,
 867         .kerberos       = true,
 868         .priority       = GENSEC_KRB5
 869 };
 870
 871 _PUBLIC_ NTSTATUS gensec_krb5_init(void)
 872 {
 873         NTSTATUS ret;
 874
 875         ret = gensec_register(&gensec_krb5_security_ops);
 876         if (!NT_STATUS_IS_OK(ret)) {
 877                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 878                         gensec_krb5_security_ops.name));
 879                 return ret;
 880         }
 881
 882         ret = gensec_register(&gensec_fake_gssapi_krb5_security_ops);
 883         if (!NT_STATUS_IS_OK(ret)) {
 884                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 885                         gensec_krb5_security_ops.name));
 886                 return ret;
 887         }
 888
 889         return ret;
 890 }