source4/smb_server/smb/negprot.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    negprot reply code
   4    Copyright (C) Andrew Tridgell 1992-1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22 #include "auth/auth.h"
  23 #include "smb_server/smb_server.h"
  24 #include "libcli/smb2/smb2.h"
  25 #include "smb_server/smb2/smb2_server.h"
  26 #include "smbd/service_stream.h"
  27 #include "lib/stream/packet.h"
  28
  29
  30 /* initialise the auth_context for this server and return the cryptkey */
  31 static NTSTATUS get_challenge(struct smbsrv_connection *smb_conn, uint8_t buff[8])
  32 {
  33         NTSTATUS nt_status;
  34         const uint8_t *challenge;
  35
  36         /* muliple negprots are not premitted */
  37         if (smb_conn->negotiate.auth_context) {
  38                 DEBUG(3,("get challenge: is this a secondary negprot?  auth_context is non-NULL!\n"));
  39                 return NT_STATUS_FOOBAR;
  40         }
  41
  42         DEBUG(10, ("get challenge: creating negprot_global_auth_context\n"));
  43
  44         nt_status = auth_context_create(smb_conn, lp_auth_methods(),
  45                                         &smb_conn->negotiate.auth_context,
  46                                         smb_conn->connection->event.ctx);
  47         if (!NT_STATUS_IS_OK(nt_status)) {
  48                 DEBUG(0, ("auth_context_create() returned %s", nt_errstr(nt_status)));
  49                 return nt_status;
  50         }
  51
  52         nt_status = auth_get_challenge(smb_conn->negotiate.auth_context, &challenge);
  53         if (!NT_STATUS_IS_OK(nt_status)) {
  54                 DEBUG(0, ("auth_get_challenge() returned %s", nt_errstr(nt_status)));
  55                 return nt_status;
  56         }
  57
  58         memcpy(buff, challenge, 8);
  59
  60         return NT_STATUS_OK;
  61 }
  62
  63 /****************************************************************************
  64  Reply for the core protocol.
  65 ****************************************************************************/
  66 static void reply_corep(struct smbsrv_request *req, uint16_t choice)
  67 {
  68         smbsrv_setup_reply(req, 1, 0);
  69
  70         SSVAL(req->out.vwv, VWV(0), choice);
  71
  72         req->smb_conn->negotiate.protocol = PROTOCOL_CORE;
  73
  74         if (req->smb_conn->signing.mandatory_signing) {
  75                 smbsrv_terminate_connection(req->smb_conn,
  76                                             "CORE does not support SMB signing, and it is mandatory\n");
  77                 return;
  78         }
  79
  80         smbsrv_send_reply(req);
  81 }
  82
  83 /****************************************************************************
  84  Reply for the coreplus protocol.
  85 this is quite incomplete - we only fill in a small part of the reply, but as nobody uses
  86 this any more it probably doesn't matter
  87 ****************************************************************************/
  88 static void reply_coreplus(struct smbsrv_request *req, uint16_t choice)
  89 {
  90         uint16_t raw = (lp_readraw()?1:0) | (lp_writeraw()?2:0);
  91
  92         smbsrv_setup_reply(req, 13, 0);
  93
  94         /* Reply, SMBlockread, SMBwritelock supported. */
  95         SCVAL(req->out.hdr,HDR_FLG,
  96               CVAL(req->out.hdr, HDR_FLG) | FLAG_SUPPORT_LOCKREAD);
  97
  98         SSVAL(req->out.vwv, VWV(0), choice);
  99         SSVAL(req->out.vwv, VWV(1), 0x1); /* user level security, don't encrypt */
 100
 101         /* tell redirector we support
 102            readbraw and writebraw (possibly) */
 103         SSVAL(req->out.vwv, VWV(5), raw);
 104
 105         req->smb_conn->negotiate.protocol = PROTOCOL_COREPLUS;
 106
 107         if (req->smb_conn->signing.mandatory_signing) {
 108                 smbsrv_terminate_connection(req->smb_conn,
 109                                             "COREPLUS does not support SMB signing, and it is mandatory\n");
 110                 return;
 111         }
 112
 113         smbsrv_send_reply(req);
 114 }
 115
 116 /****************************************************************************
 117  Reply for the lanman 1.0 protocol.
 118 ****************************************************************************/
 119 static void reply_lanman1(struct smbsrv_request *req, uint16_t choice)
 120 {
 121         int raw = (lp_readraw()?1:0) | (lp_writeraw()?2:0);
 122         int secword=0;
 123         time_t t = req->request_time.tv_sec;
 124
 125         req->smb_conn->negotiate.encrypted_passwords = lp_encrypted_passwords();
 126
 127         if (lp_security() != SEC_SHARE)
 128                 secword |= NEGOTIATE_SECURITY_USER_LEVEL;
 129
 130         if (req->smb_conn->negotiate.encrypted_passwords)
 131                 secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
 132
 133         req->smb_conn->negotiate.protocol = PROTOCOL_LANMAN1;
 134
 135         smbsrv_setup_reply(req, 13, req->smb_conn->negotiate.encrypted_passwords ? 8 : 0);
 136
 137         /* SMBlockread, SMBwritelock supported. */
 138         SCVAL(req->out.hdr,HDR_FLG,
 139               CVAL(req->out.hdr, HDR_FLG) | FLAG_SUPPORT_LOCKREAD);
 140
 141         SSVAL(req->out.vwv, VWV(0), choice);
 142         SSVAL(req->out.vwv, VWV(1), secword);
 143         SSVAL(req->out.vwv, VWV(2), req->smb_conn->negotiate.max_recv);
 144         SSVAL(req->out.vwv, VWV(3), lp_maxmux());
 145         SSVAL(req->out.vwv, VWV(4), 1);
 146         SSVAL(req->out.vwv, VWV(5), raw);
 147         SIVAL(req->out.vwv, VWV(6), req->smb_conn->connection->server_id);
 148         srv_push_dos_date(req->smb_conn, req->out.vwv, VWV(8), t);
 149         SSVAL(req->out.vwv, VWV(10), req->smb_conn->negotiate.zone_offset/60);
 150         SIVAL(req->out.vwv, VWV(11), 0); /* reserved */
 151
 152         /* Create a token value and add it to the outgoing packet. */
 153         if (req->smb_conn->negotiate.encrypted_passwords) {
 154                 NTSTATUS nt_status;
 155
 156                 SSVAL(req->out.vwv, VWV(11), 8);
 157
 158                 nt_status = get_challenge(req->smb_conn, req->out.data);
 159                 if (!NT_STATUS_IS_OK(nt_status)) {
 160                         smbsrv_terminate_connection(req->smb_conn, "LANMAN1 get_challenge failed\n");
 161                         return;
 162                 }
 163         }
 164
 165         if (req->smb_conn->signing.mandatory_signing) {
 166                 smbsrv_terminate_connection(req->smb_conn,
 167                                             "LANMAN1 does not support SMB signing, and it is mandatory\n");
 168                 return;
 169         }
 170
 171         smbsrv_send_reply(req);
 172 }
 173
 174 /****************************************************************************
 175  Reply for the lanman 2.0 protocol.
 176 ****************************************************************************/
 177 static void reply_lanman2(struct smbsrv_request *req, uint16_t choice)
 178 {
 179         int raw = (lp_readraw()?1:0) | (lp_writeraw()?2:0);
 180         int secword=0;
 181         time_t t = req->request_time.tv_sec;
 182
 183         req->smb_conn->negotiate.encrypted_passwords = lp_encrypted_passwords();
 184
 185         if (lp_security() != SEC_SHARE)
 186                 secword |= NEGOTIATE_SECURITY_USER_LEVEL;
 187
 188         if (req->smb_conn->negotiate.encrypted_passwords)
 189                 secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
 190
 191         req->smb_conn->negotiate.protocol = PROTOCOL_LANMAN2;
 192
 193         smbsrv_setup_reply(req, 13, 0);
 194
 195         SSVAL(req->out.vwv, VWV(0), choice);
 196         SSVAL(req->out.vwv, VWV(1), secword);
 197         SSVAL(req->out.vwv, VWV(2), req->smb_conn->negotiate.max_recv);
 198         SSVAL(req->out.vwv, VWV(3), lp_maxmux());
 199         SSVAL(req->out.vwv, VWV(4), 1);
 200         SSVAL(req->out.vwv, VWV(5), raw);
 201         SIVAL(req->out.vwv, VWV(6), req->smb_conn->connection->server_id);
 202         srv_push_dos_date(req->smb_conn, req->out.vwv, VWV(8), t);
 203         SSVAL(req->out.vwv, VWV(10), req->smb_conn->negotiate.zone_offset/60);
 204         SIVAL(req->out.vwv, VWV(11), 0);
 205
 206         /* Create a token value and add it to the outgoing packet. */
 207         if (req->smb_conn->negotiate.encrypted_passwords) {
 208                 SSVAL(req->out.vwv, VWV(11), 8);
 209                 req_grow_data(req, 8);
 210                 get_challenge(req->smb_conn, req->out.data);
 211         }
 212
 213         req_push_str(req, NULL, lp_workgroup(), -1, STR_TERMINATE);
 214
 215         if (req->smb_conn->signing.mandatory_signing) {
 216                 smbsrv_terminate_connection(req->smb_conn,
 217                                             "LANMAN2 does not support SMB signing, and it is mandatory\n");
 218                 return;
 219         }
 220
 221         smbsrv_send_reply(req);
 222 }
 223
 224 static void reply_nt1_orig(struct smbsrv_request *req)
 225 {
 226         /* Create a token value and add it to the outgoing packet. */
 227         if (req->smb_conn->negotiate.encrypted_passwords) {
 228                 req_grow_data(req, 8);
 229                 /* note that we do not send a challenge at all if
 230                    we are using plaintext */
 231                 get_challenge(req->smb_conn, req->out.ptr);
 232                 req->out.ptr += 8;
 233                 SCVAL(req->out.vwv+1, VWV(16), 8);
 234         }
 235         req_push_str(req, NULL, lp_workgroup(), -1, STR_UNICODE|STR_TERMINATE|STR_NOALIGN);
 236         req_push_str(req, NULL, lp_netbios_name(), -1, STR_UNICODE|STR_TERMINATE|STR_NOALIGN);
 237         DEBUG(3,("not using extended security (SPNEGO or NTLMSSP)\n"));
 238 }
 239
 240 /****************************************************************************
 241  Reply for the nt protocol.
 242 ****************************************************************************/
 243 static void reply_nt1(struct smbsrv_request *req, uint16_t choice)
 244 {
 245         /* dual names + lock_and_read + nt SMBs + remote API calls */
 246         int capabilities;
 247         int secword=0;
 248         time_t t = req->request_time.tv_sec;
 249         NTTIME nttime;
 250         BOOL negotiate_spnego = False;
 251
 252         unix_to_nt_time(&nttime, t);
 253
 254         capabilities =
 255                 CAP_NT_FIND | CAP_LOCK_AND_READ |
 256                 CAP_LEVEL_II_OPLOCKS | CAP_NT_SMBS | CAP_RPC_REMOTE_APIS;
 257
 258         req->smb_conn->negotiate.encrypted_passwords = lp_encrypted_passwords();
 259
 260         /* do spnego in user level security if the client
 261            supports it and we can do encrypted passwords */
 262
 263         if (req->smb_conn->negotiate.encrypted_passwords &&
 264             (lp_security() != SEC_SHARE) &&
 265             lp_use_spnego() &&
 266             (req->flags2 & FLAGS2_EXTENDED_SECURITY)) {
 267                 negotiate_spnego = True;
 268                 capabilities |= CAP_EXTENDED_SECURITY;
 269         }
 270
 271         if (lp_unix_extensions()) {
 272                 capabilities |= CAP_UNIX;
 273         }
 274
 275         if (lp_large_readwrite()) {
 276                 capabilities |= CAP_LARGE_READX | CAP_LARGE_WRITEX | CAP_W2K_SMBS;
 277         }
 278
 279         capabilities |= CAP_LARGE_FILES;
 280
 281         if (lp_readraw() && lp_writeraw()) {
 282                 capabilities |= CAP_RAW_MODE;
 283         }
 284
 285         /* allow for disabling unicode */
 286         if (lp_unicode()) {
 287                 capabilities |= CAP_UNICODE;
 288         }
 289
 290         if (lp_nt_status_support()) {
 291                 capabilities |= CAP_STATUS32;
 292         }
 293
 294         if (lp_host_msdfs()) {
 295                 capabilities |= CAP_DFS;
 296         }
 297
 298         if (lp_security() != SEC_SHARE) {
 299                 secword |= NEGOTIATE_SECURITY_USER_LEVEL;
 300         }
 301
 302         if (req->smb_conn->negotiate.encrypted_passwords) {
 303                 secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
 304         }
 305
 306         if (req->smb_conn->signing.allow_smb_signing) {
 307                 secword |= NEGOTIATE_SECURITY_SIGNATURES_ENABLED;
 308         }
 309
 310         if (req->smb_conn->signing.mandatory_signing) {
 311                 secword |= NEGOTIATE_SECURITY_SIGNATURES_REQUIRED;
 312         }
 313
 314         req->smb_conn->negotiate.protocol = PROTOCOL_NT1;
 315
 316         smbsrv_setup_reply(req, 17, 0);
 317
 318         SSVAL(req->out.vwv, VWV(0), choice);
 319         SCVAL(req->out.vwv, VWV(1), secword);
 320
 321         /* notice the strange +1 on vwv here? That's because
 322            this is the one and only SMB packet that is malformed in
 323            the specification - all the command words after the secword
 324            are offset by 1 byte */
 325         SSVAL(req->out.vwv+1, VWV(1), lp_maxmux());
 326         SSVAL(req->out.vwv+1, VWV(2), 1); /* num vcs */
 327         SIVAL(req->out.vwv+1, VWV(3), req->smb_conn->negotiate.max_recv);
 328         SIVAL(req->out.vwv+1, VWV(5), 0x10000); /* raw size. full 64k */
 329         SIVAL(req->out.vwv+1, VWV(7), req->smb_conn->connection->server_id); /* session key */
 330         SIVAL(req->out.vwv+1, VWV(9), capabilities);
 331         push_nttime(req->out.vwv+1, VWV(11), nttime);
 332         SSVALS(req->out.vwv+1,VWV(15), req->smb_conn->negotiate.zone_offset/60);
 333
 334         if (!negotiate_spnego) {
 335                 reply_nt1_orig(req);
 336         } else {
 337                 struct cli_credentials *server_credentials;
 338                 struct gensec_security *gensec_security;
 339                 DATA_BLOB null_data_blob = data_blob(NULL, 0);
 340                 DATA_BLOB blob;
 341                 const char *oid;
 342                 NTSTATUS nt_status = gensec_server_start(req->smb_conn,
 343                                                          &gensec_security,
 344                                                          req->smb_conn->connection->event.ctx);
 345
 346                 if (!NT_STATUS_IS_OK(nt_status)) {
 347                         DEBUG(0, ("Failed to start GENSEC: %s\n", nt_errstr(nt_status)));
 348                         smbsrv_terminate_connection(req->smb_conn, "Failed to start GENSEC\n");
 349                         return;
 350                 }
 351
 352                 if (req->smb_conn->negotiate.auth_context) {
 353                         smbsrv_terminate_connection(req->smb_conn, "reply_nt1: is this a secondary negprot?  auth_context is non-NULL!\n");
 354                         return;
 355                 }
 356
 357                 server_credentials
 358                         = cli_credentials_init(req);
 359                 if (!server_credentials) {
 360                         smbsrv_terminate_connection(req->smb_conn, "Failed to init server credentials\n");
 361                         return;
 362                 }
 363
 364                 cli_credentials_set_conf(server_credentials);
 365                 nt_status = cli_credentials_set_machine_account(server_credentials);
 366                 if (!NT_STATUS_IS_OK(nt_status)) {
 367                         DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(nt_status)));
 368                         talloc_free(server_credentials);
 369                         server_credentials = NULL;
 370                 }
 371
 372                 req->smb_conn->negotiate.server_credentials = talloc_steal(req->smb_conn, server_credentials);
 373
 374                 gensec_set_target_service(gensec_security, "cifs");
 375
 376                 gensec_set_credentials(gensec_security, server_credentials);
 377
 378                 oid = GENSEC_OID_SPNEGO;
 379                 nt_status = gensec_start_mech_by_oid(gensec_security, oid);
 380
 381                 if (NT_STATUS_IS_OK(nt_status)) {
 382                         /* Get and push the proposed OID list into the packets */
 383                         nt_status = gensec_update(gensec_security, req, null_data_blob, &blob);
 384
 385                         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 386                                 DEBUG(1, ("Failed to get SPNEGO to give us the first token: %s\n", nt_errstr(nt_status)));
 387                         }
 388                 }
 389
 390                 if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 391                         DEBUG(3,("using SPNEGO\n"));
 392                 } else {
 393                         DEBUG(5, ("Failed to start SPNEGO, falling back to NTLMSSP only: %s\n", nt_errstr(nt_status)));
 394                         oid = GENSEC_OID_NTLMSSP;
 395                         nt_status = gensec_start_mech_by_oid(gensec_security, oid);
 396
 397                         if (!NT_STATUS_IS_OK(nt_status)) {
 398                                 DEBUG(0, ("Failed to start SPNEGO as well as NTLMSSP fallback: %s\n", nt_errstr(nt_status)));
 399                                 reply_nt1_orig(req);
 400                                 return;
 401                         }
 402                         /* NTLMSSP is a client-first exchange */
 403                         blob = data_blob(NULL, 0);
 404                         DEBUG(3,("using raw-NTLMSSP\n"));
 405                 }
 406
 407                 req->smb_conn->negotiate.oid = oid;
 408
 409                 req_grow_data(req, blob.length + 16);
 410                 /* a NOT very random guid, perhaps we should get it
 411                  * from the credentials (kitchen sink...) */
 412                 memset(req->out.ptr, '\0', 16);
 413                 req->out.ptr += 16;
 414
 415                 memcpy(req->out.ptr, blob.data, blob.length);
 416                 SCVAL(req->out.vwv+1, VWV(16), blob.length + 16);
 417                 req->out.ptr += blob.length;
 418         }
 419
 420         smbsrv_send_reply_nosign(req);
 421 }
 422
 423 /*
 424  after a SMB2 2.001 negprot reply to a SMB negprot request
 425  no (SMB or SMB2) requests are allowed anymore,
 426  vista resets the connection in this case
 427 */
 428 static NTSTATUS smbsrv_recv_disabled_request(void *private, DATA_BLOB blob)
 429 {
 430         struct smbsrv_connection *smb_conn = talloc_get_type(private, struct smbsrv_connection);
 431         smbsrv_terminate_connection(smb_conn, "Receive Packet after SMB -> SMB2 negprot");
 432         return NT_STATUS_OK;
 433 }
 434
 435 /****************************************************************************
 436  Reply for the SMB2 2.001 protocol
 437 ****************************************************************************/
 438 static void reply_smb2(struct smbsrv_request *req, uint16_t choice)
 439 {
 440         struct smbsrv_connection *smb_conn = req->smb_conn;
 441
 442         /* reply with a SMB2 packet */
 443         smb2srv_reply_smb_negprot(req);
 444         req = NULL;
 445
 446         /* disallow requests */
 447         packet_set_callback(smb_conn->packet, smbsrv_recv_disabled_request);
 448 }
 449
 450 /* List of supported protocols, most desired first */
 451 static const struct {
 452         const char *proto_name;
 453         const char *short_name;
 454         void (*proto_reply_fn)(struct smbsrv_request *req, uint16_t choice);
 455         int protocol_level;
 456 } supported_protocols[] = {
 457         {"SMB 2.001",                   "SMB2",         reply_smb2,     PROTOCOL_SMB2},
 458         {"NT LANMAN 1.0",               "NT1",          reply_nt1,      PROTOCOL_NT1},
 459         {"NT LM 0.12",                  "NT1",          reply_nt1,      PROTOCOL_NT1},
 460         {"LANMAN2.1",                   "LANMAN2",      reply_lanman2,  PROTOCOL_LANMAN2},
 461         {"LM1.2X002",                   "LANMAN2",      reply_lanman2,  PROTOCOL_LANMAN2},
 462         {"Samba",                       "LANMAN2",      reply_lanman2,  PROTOCOL_LANMAN2},
 463         {"DOS LM1.2X002",               "LANMAN2",      reply_lanman2,  PROTOCOL_LANMAN2},
 464         {"Windows for Workgroups 3.1a", "LANMAN1",      reply_lanman1,  PROTOCOL_LANMAN1},
 465         {"LANMAN1.0",                   "LANMAN1",      reply_lanman1,  PROTOCOL_LANMAN1},
 466         {"MICROSOFT NETWORKS 3.0",      "LANMAN1",      reply_lanman1,  PROTOCOL_LANMAN1},
 467         {"MICROSOFT NETWORKS 1.03",     "COREPLUS",     reply_coreplus, PROTOCOL_COREPLUS},
 468         {"PC NETWORK PROGRAM 1.0",      "CORE",         reply_corep,    PROTOCOL_CORE},
 469         {NULL,NULL,NULL,0},
 470 };
 471
 472 /****************************************************************************
 473  Reply to a negprot.
 474 ****************************************************************************/
 475
 476 void smbsrv_reply_negprot(struct smbsrv_request *req)
 477 {
 478         int protocol;
 479         uint8_t *p;
 480         uint32_t protos_count = 0;
 481         char **protos = NULL;
 482
 483         if (req->smb_conn->negotiate.done_negprot) {
 484                 smbsrv_terminate_connection(req->smb_conn, "multiple negprot's are not permitted");
 485                 return;
 486         }
 487         req->smb_conn->negotiate.done_negprot = True;
 488
 489         p = req->in.data;
 490         while (True) {
 491                 size_t len;
 492
 493                 protos = talloc_realloc(req, protos, char *, protos_count + 1);
 494                 if (!protos) {
 495                         smbsrv_terminate_connection(req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
 496                         return;
 497                 }
 498                 protos[protos_count] = NULL;
 499                 len = req_pull_ascii4(req, (const char **)&protos[protos_count], p, STR_ASCII|STR_TERMINATE);
 500                 p += len;
 501                 if (len == 0 || !protos[protos_count]) break;
 502
 503                 DEBUG(3,("Requested protocol [%d][%s]\n", protos_count, protos[protos_count]));
 504                 protos_count++;
 505         }
 506
 507         /* Check for protocols, most desirable first */
 508         for (protocol = 0; supported_protocols[protocol].proto_name; protocol++) {
 509                 int i;
 510
 511                 if (supported_protocols[protocol].protocol_level > lp_maxprotocol()) continue;
 512                 if (supported_protocols[protocol].protocol_level < lp_minprotocol()) continue;
 513
 514                 for (i = 0; i < protos_count; i++) {
 515                         if (strcmp(supported_protocols[protocol].proto_name, protos[i]) != 0) continue;
 516
 517                         supported_protocols[protocol].proto_reply_fn(req, i);
 518                         sub_set_remote_proto(supported_protocols[protocol].short_name);
 519                         DEBUG(3,("Selected protocol [%d][%s]\n",
 520                                 i, supported_protocols[protocol].proto_name));
 521                         return;
 522                 }
 523         }
 524
 525         smbsrv_terminate_connection(req->smb_conn, "No protocol supported !");
 526 }