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