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 3 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, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "system/filesys.h"
  22 #include "auth/credentials/credentials.h"
  23 #include "auth/gensec/gensec.h"
  24 #include "auth/auth.h"
  25 #include "smb_server/smb_server.h"
  26 #include "libcli/smb2/smb2.h"
  27 #include "smb_server/smb2/smb2_server.h"
  28 #include "smbd/service_stream.h"
  29 #include "lib/stream/packet.h"
  30 #include "param/param.h"
  31
  32
  33 /* initialise the auth_context for this server and return the cryptkey */
  34 static NTSTATUS get_challenge(struct smbsrv_connection *smb_conn, uint8_t buff[8])
  35 {
  36         NTSTATUS nt_status;
  37
  38         /* muliple negprots are not premitted */
  39         if (smb_conn->negotiate.auth_context) {
  40                 DEBUG(3,("get challenge: is this a secondary negprot?  auth_context is non-NULL!\n"));
  41                 return NT_STATUS_FOOBAR;
  42         }
  43
  44         DEBUG(10, ("get challenge: creating negprot_global_auth_context\n"));
  45
  46         nt_status = auth_context_create(smb_conn,
  47                                         smb_conn->connection->event.ctx,
  48                                         smb_conn->connection->msg_ctx,
  49                                         smb_conn->lp_ctx,
  50                                         &smb_conn->negotiate.auth_context);
  51         if (!NT_STATUS_IS_OK(nt_status)) {
  52                 DEBUG(0, ("auth_context_create() returned %s", nt_errstr(nt_status)));
  53                 return nt_status;
  54         }
  55
  56         nt_status = auth_get_challenge(smb_conn->negotiate.auth_context, buff);
  57         if (!NT_STATUS_IS_OK(nt_status)) {
  58                 DEBUG(0, ("auth_get_challenge() returned %s", nt_errstr(nt_status)));
  59                 return nt_status;
  60         }
  61
  62         return NT_STATUS_OK;
  63 }
  64
  65 /****************************************************************************
  66  Reply for the core protocol.
  67 ****************************************************************************/
  68 static void reply_corep(struct smbsrv_request *req, uint16_t choice)
  69 {
  70         smbsrv_setup_reply(req, 1, 0);
  71
  72         SSVAL(req->out.vwv, VWV(0), choice);
  73
  74         req->smb_conn->negotiate.protocol = PROTOCOL_CORE;
  75
  76         if (req->smb_conn->signing.mandatory_signing) {
  77                 smbsrv_terminate_connection(req->smb_conn,
  78                                             "CORE does not support SMB signing, and it is mandatory\n");
  79                 return;
  80         }
  81
  82         smbsrv_send_reply(req);
  83 }
  84
  85 /****************************************************************************
  86  Reply for the coreplus protocol.
  87 this is quite incomplete - we only fill in a small part of the reply, but as nobody uses
  88 this any more it probably doesn't matter
  89 ****************************************************************************/
  90 static void reply_coreplus(struct smbsrv_request *req, uint16_t choice)
  91 {
  92         uint16_t raw;
  93         if (lpcfg_async_smb_echo_handler(req->smb_conn->lp_ctx)) {
  94                 raw = 0;
  95         } else {
  96                 raw = (lpcfg_read_raw(req->smb_conn->lp_ctx)?1:0) |
  97                       (lpcfg_write_raw(req->smb_conn->lp_ctx)?2:0);
  98         }
  99
 100         smbsrv_setup_reply(req, 13, 0);
 101
 102         /* Reply, SMBlockread, SMBwritelock supported. */
 103         SCVAL(req->out.hdr,HDR_FLG,
 104               CVAL(req->out.hdr, HDR_FLG) | FLAG_SUPPORT_LOCKREAD);
 105
 106         SSVAL(req->out.vwv, VWV(0), choice);
 107         SSVAL(req->out.vwv, VWV(1), 0x1); /* user level security, don't encrypt */
 108
 109         /* tell redirector we support
 110            readbraw and writebraw (possibly) */
 111         SSVAL(req->out.vwv, VWV(5), raw);
 112
 113         req->smb_conn->negotiate.protocol = PROTOCOL_COREPLUS;
 114
 115         if (req->smb_conn->signing.mandatory_signing) {
 116                 smbsrv_terminate_connection(req->smb_conn,
 117                                             "COREPLUS does not support SMB signing, and it is mandatory\n");
 118                 return;
 119         }
 120
 121         smbsrv_send_reply(req);
 122 }
 123
 124 /****************************************************************************
 125  Reply for the lanman 1.0 protocol.
 126 ****************************************************************************/
 127 static void reply_lanman1(struct smbsrv_request *req, uint16_t choice)
 128 {
 129         int secword=0;
 130         time_t t = req->request_time.tv_sec;
 131         uint16_t raw;
 132
 133         if (lpcfg_async_smb_echo_handler(req->smb_conn->lp_ctx)) {
 134                 raw = 0;
 135         } else {
 136                 raw = (lpcfg_read_raw(req->smb_conn->lp_ctx)?1:0) |
 137                       (lpcfg_write_raw(req->smb_conn->lp_ctx)?2:0);
 138         }
 139
 140         req->smb_conn->negotiate.encrypted_passwords = lpcfg_encrypt_passwords(req->smb_conn->lp_ctx);
 141
 142         if (req->smb_conn->negotiate.encrypted_passwords)
 143                 secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
 144
 145         req->smb_conn->negotiate.protocol = PROTOCOL_LANMAN1;
 146
 147         smbsrv_setup_reply(req, 13, req->smb_conn->negotiate.encrypted_passwords ? 8 : 0);
 148
 149         /* SMBlockread, SMBwritelock supported. */
 150         SCVAL(req->out.hdr,HDR_FLG,
 151               CVAL(req->out.hdr, HDR_FLG) | FLAG_SUPPORT_LOCKREAD);
 152
 153         SSVAL(req->out.vwv, VWV(0), choice);
 154         SSVAL(req->out.vwv, VWV(1), secword);
 155         SSVAL(req->out.vwv, VWV(2), req->smb_conn->negotiate.max_recv);
 156         SSVAL(req->out.vwv, VWV(3), lpcfg_max_mux(req->smb_conn->lp_ctx));
 157         SSVAL(req->out.vwv, VWV(4), 1);
 158         SSVAL(req->out.vwv, VWV(5), raw);
 159         SIVAL(req->out.vwv, VWV(6), req->smb_conn->connection->server_id.pid);
 160         srv_push_dos_date(req->smb_conn, req->out.vwv, VWV(8), t);
 161         SSVAL(req->out.vwv, VWV(10), req->smb_conn->negotiate.zone_offset/60);
 162         SIVAL(req->out.vwv, VWV(11), 0); /* reserved */
 163
 164         /* Create a token value and add it to the outgoing packet. */
 165         if (req->smb_conn->negotiate.encrypted_passwords) {
 166                 NTSTATUS nt_status;
 167
 168                 SSVAL(req->out.vwv, VWV(11), 8);
 169
 170                 nt_status = get_challenge(req->smb_conn, req->out.data);
 171                 if (!NT_STATUS_IS_OK(nt_status)) {
 172                         smbsrv_terminate_connection(req->smb_conn, "LANMAN1 get_challenge failed\n");
 173                         return;
 174                 }
 175         }
 176
 177         if (req->smb_conn->signing.mandatory_signing) {
 178                 smbsrv_terminate_connection(req->smb_conn,
 179                                             "LANMAN1 does not support SMB signing, and it is mandatory\n");
 180                 return;
 181         }
 182
 183         smbsrv_send_reply(req);
 184 }
 185
 186 /****************************************************************************
 187  Reply for the lanman 2.0 protocol.
 188 ****************************************************************************/
 189 static void reply_lanman2(struct smbsrv_request *req, uint16_t choice)
 190 {
 191         int secword=0;
 192         time_t t = req->request_time.tv_sec;
 193         uint16_t raw;
 194         if (lpcfg_async_smb_echo_handler(req->smb_conn->lp_ctx)) {
 195                 raw = 0;
 196         } else {
 197                 raw = (lpcfg_read_raw(req->smb_conn->lp_ctx)?1:0) |
 198                       (lpcfg_write_raw(req->smb_conn->lp_ctx)?2:0);
 199         }
 200
 201         req->smb_conn->negotiate.encrypted_passwords = lpcfg_encrypt_passwords(req->smb_conn->lp_ctx);
 202
 203         if (req->smb_conn->negotiate.encrypted_passwords)
 204                 secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
 205
 206         req->smb_conn->negotiate.protocol = PROTOCOL_LANMAN2;
 207
 208         smbsrv_setup_reply(req, 13, 0);
 209
 210         SSVAL(req->out.vwv, VWV(0), choice);
 211         SSVAL(req->out.vwv, VWV(1), secword);
 212         SSVAL(req->out.vwv, VWV(2), req->smb_conn->negotiate.max_recv);
 213         SSVAL(req->out.vwv, VWV(3), lpcfg_max_mux(req->smb_conn->lp_ctx));
 214         SSVAL(req->out.vwv, VWV(4), 1);
 215         SSVAL(req->out.vwv, VWV(5), raw);
 216         SIVAL(req->out.vwv, VWV(6), req->smb_conn->connection->server_id.pid);
 217         srv_push_dos_date(req->smb_conn, req->out.vwv, VWV(8), t);
 218         SSVAL(req->out.vwv, VWV(10), req->smb_conn->negotiate.zone_offset/60);
 219         SIVAL(req->out.vwv, VWV(11), 0);
 220
 221         /* Create a token value and add it to the outgoing packet. */
 222         if (req->smb_conn->negotiate.encrypted_passwords) {
 223                 SSVAL(req->out.vwv, VWV(11), 8);
 224                 req_grow_data(req, 8);
 225                 get_challenge(req->smb_conn, req->out.data);
 226         }
 227
 228         req_push_str(req, NULL, lpcfg_workgroup(req->smb_conn->lp_ctx), -1, STR_TERMINATE);
 229
 230         if (req->smb_conn->signing.mandatory_signing) {
 231                 smbsrv_terminate_connection(req->smb_conn,
 232                                             "LANMAN2 does not support SMB signing, and it is mandatory\n");
 233                 return;
 234         }
 235
 236         smbsrv_send_reply(req);
 237 }
 238
 239 static void reply_nt1_orig(struct smbsrv_request *req)
 240 {
 241         /* Create a token value and add it to the outgoing packet. */
 242         if (req->smb_conn->negotiate.encrypted_passwords) {
 243                 req_grow_data(req, 8);
 244                 /* note that we do not send a challenge at all if
 245                    we are using plaintext */
 246                 get_challenge(req->smb_conn, req->out.ptr);
 247                 req->out.ptr += 8;
 248                 SCVAL(req->out.vwv+1, VWV(16), 8);
 249         }
 250         req_push_str(req, NULL, lpcfg_workgroup(req->smb_conn->lp_ctx), -1, STR_UNICODE|STR_TERMINATE|STR_NOALIGN);
 251         req_push_str(req, NULL, lpcfg_netbios_name(req->smb_conn->lp_ctx), -1, STR_UNICODE|STR_TERMINATE|STR_NOALIGN);
 252         DEBUG(3,("not using extended security (SPNEGO or NTLMSSP)\n"));
 253 }
 254
 255 /*
 256   try to determine if the filesystem supports large files
 257 */
 258 static bool large_file_support(const char *path)
 259 {
 260         int fd;
 261         ssize_t ret;
 262         char c;
 263
 264         fd = open(path, O_RDWR|O_CREAT, 0600);
 265         unlink(path);
 266         if (fd == -1) {
 267                 /* have to assume large files are OK */
 268                 return true;
 269         }
 270         ret = pread(fd, &c, 1, ((uint64_t)1)<<32);
 271         close(fd);
 272         return ret == 0;
 273 }
 274
 275 /****************************************************************************
 276  Reply for the nt protocol.
 277 ****************************************************************************/
 278 static void reply_nt1(struct smbsrv_request *req, uint16_t choice)
 279 {
 280         /* dual names + lock_and_read + nt SMBs + remote API calls */
 281         int capabilities;
 282         int secword=0;
 283         time_t t = req->request_time.tv_sec;
 284         NTTIME nttime;
 285         bool negotiate_spnego = false;
 286         char *large_test_path;
 287
 288         unix_to_nt_time(&nttime, t);
 289
 290         capabilities =
 291                 CAP_NT_FIND | CAP_LOCK_AND_READ |
 292                 CAP_LEVEL_II_OPLOCKS | CAP_NT_SMBS | CAP_RPC_REMOTE_APIS;
 293
 294         req->smb_conn->negotiate.encrypted_passwords = lpcfg_encrypt_passwords(req->smb_conn->lp_ctx);
 295
 296         /* do spnego in user level security if the client
 297            supports it and we can do encrypted passwords */
 298
 299         if (req->smb_conn->negotiate.encrypted_passwords &&
 300             (req->flags2 & FLAGS2_EXTENDED_SECURITY)) {
 301                 negotiate_spnego = true;
 302                 capabilities |= CAP_EXTENDED_SECURITY;
 303         }
 304
 305         if (lpcfg_large_readwrite(req->smb_conn->lp_ctx)) {
 306                 capabilities |= CAP_LARGE_READX | CAP_LARGE_WRITEX | CAP_W2K_SMBS;
 307         }
 308
 309         large_test_path = lpcfg_lock_path(req, req->smb_conn->lp_ctx, "large_test.dat");
 310         if (large_file_support(large_test_path)) {
 311                 capabilities |= CAP_LARGE_FILES;
 312         }
 313
 314         if (!lpcfg_async_smb_echo_handler(req->smb_conn->lp_ctx) &&
 315             lpcfg_read_raw(req->smb_conn->lp_ctx) &&
 316             lpcfg_write_raw(req->smb_conn->lp_ctx)) {
 317                 capabilities |= CAP_RAW_MODE;
 318         }
 319
 320         /* allow for disabling unicode */
 321         if (lpcfg_unicode(req->smb_conn->lp_ctx)) {
 322                 capabilities |= CAP_UNICODE;
 323         }
 324
 325         if (lpcfg_nt_status_support(req->smb_conn->lp_ctx)) {
 326                 capabilities |= CAP_STATUS32;
 327         }
 328
 329         if (lpcfg_host_msdfs(req->smb_conn->lp_ctx)) {
 330                 capabilities |= CAP_DFS;
 331         }
 332
 333         secword |= NEGOTIATE_SECURITY_USER_LEVEL;
 334
 335         if (req->smb_conn->negotiate.encrypted_passwords) {
 336                 secword |= NEGOTIATE_SECURITY_CHALLENGE_RESPONSE;
 337         }
 338
 339         if (req->smb_conn->signing.allow_smb_signing) {
 340                 secword |= NEGOTIATE_SECURITY_SIGNATURES_ENABLED;
 341         }
 342
 343         if (req->smb_conn->signing.mandatory_signing) {
 344                 secword |= NEGOTIATE_SECURITY_SIGNATURES_REQUIRED;
 345         }
 346
 347         req->smb_conn->negotiate.protocol = PROTOCOL_NT1;
 348
 349         smbsrv_setup_reply(req, 17, 0);
 350
 351         SSVAL(req->out.vwv, VWV(0), choice);
 352         SCVAL(req->out.vwv, VWV(1), secword);
 353
 354         /* notice the strange +1 on vwv here? That's because
 355            this is the one and only SMB packet that is malformed in
 356            the specification - all the command words after the secword
 357            are offset by 1 byte */
 358         SSVAL(req->out.vwv+1, VWV(1), lpcfg_max_mux(req->smb_conn->lp_ctx));
 359         SSVAL(req->out.vwv+1, VWV(2), 1); /* num vcs */
 360         SIVAL(req->out.vwv+1, VWV(3), req->smb_conn->negotiate.max_recv);
 361         SIVAL(req->out.vwv+1, VWV(5), 0x10000); /* raw size. full 64k */
 362         SIVAL(req->out.vwv+1, VWV(7), req->smb_conn->connection->server_id.pid); /* session key */
 363
 364         SIVAL(req->out.vwv+1, VWV(9), capabilities);
 365         push_nttime(req->out.vwv+1, VWV(11), nttime);
 366         SSVALS(req->out.vwv+1,VWV(15), req->smb_conn->negotiate.zone_offset/60);
 367
 368         if (!negotiate_spnego) {
 369                 reply_nt1_orig(req);
 370         } else {
 371                 struct cli_credentials *server_credentials;
 372                 struct gensec_security *gensec_security;
 373                 DATA_BLOB null_data_blob = data_blob(NULL, 0);
 374                 DATA_BLOB blob;
 375                 const char *oid;
 376                 NTSTATUS nt_status;
 377
 378                 server_credentials
 379                         = cli_credentials_init(req);
 380                 if (!server_credentials) {
 381                         smbsrv_terminate_connection(req->smb_conn, "Failed to init server credentials\n");
 382                         return;
 383                 }
 384
 385                 cli_credentials_set_conf(server_credentials, req->smb_conn->lp_ctx);
 386                 nt_status = cli_credentials_set_machine_account(server_credentials, req->smb_conn->lp_ctx);
 387                 if (!NT_STATUS_IS_OK(nt_status)) {
 388                         DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(nt_status)));
 389                         /*
 390                          * We keep the server_credentials as anonymous
 391                          * this is required for the spoolss.notify test
 392                          */
 393                 }
 394
 395                 nt_status = samba_server_gensec_start(req,
 396                                                       req->smb_conn->connection->event.ctx,
 397                                                       req->smb_conn->connection->msg_ctx,
 398                                                       req->smb_conn->lp_ctx,
 399                                                       server_credentials,
 400                                                       "cifs",
 401                                                       &gensec_security);
 402
 403                 if (!NT_STATUS_IS_OK(nt_status)) {
 404                         DEBUG(0, ("Failed to start GENSEC: %s\n", nt_errstr(nt_status)));
 405                         smbsrv_terminate_connection(req->smb_conn, "Failed to start GENSEC\n");
 406                         return;
 407                 }
 408
 409                 if (req->smb_conn->negotiate.auth_context) {
 410                         smbsrv_terminate_connection(req->smb_conn, "reply_nt1: is this a secondary negprot?  auth_context is non-NULL!\n");
 411                         return;
 412                 }
 413                 req->smb_conn->negotiate.server_credentials = talloc_reparent(req, req->smb_conn, server_credentials);
 414
 415                 oid = GENSEC_OID_SPNEGO;
 416                 nt_status = gensec_start_mech_by_oid(gensec_security, oid);
 417
 418                 if (NT_STATUS_IS_OK(nt_status)) {
 419                         /* Get and push the proposed OID list into the packets */
 420                         nt_status = gensec_update(gensec_security, req,
 421                                                   null_data_blob, &blob);
 422
 423                         if (!NT_STATUS_IS_OK(nt_status) && !NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 424                                 DEBUG(1, ("Failed to get SPNEGO to give us the first token: %s\n", nt_errstr(nt_status)));
 425                         }
 426                 }
 427
 428                 if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 429                         DEBUG(3,("using SPNEGO\n"));
 430                 } else {
 431                         DEBUG(5, ("Failed to start SPNEGO, falling back to NTLMSSP only: %s\n", nt_errstr(nt_status)));
 432                         oid = GENSEC_OID_NTLMSSP;
 433                         nt_status = gensec_start_mech_by_oid(gensec_security, oid);
 434
 435                         if (!NT_STATUS_IS_OK(nt_status)) {
 436                                 DEBUG(0, ("Failed to start SPNEGO as well as NTLMSSP fallback: %s\n", nt_errstr(nt_status)));
 437                                 reply_nt1_orig(req);
 438                                 return;
 439                         }
 440                         /* NTLMSSP is a client-first exchange */
 441                         blob = data_blob(NULL, 0);
 442                         DEBUG(3,("using raw-NTLMSSP\n"));
 443                 }
 444
 445                 req->smb_conn->negotiate.oid = oid;
 446
 447                 req_grow_data(req, blob.length + 16);
 448                 /* a NOT very random guid, perhaps we should get it
 449                  * from the credentials (kitchen sink...) */
 450                 memset(req->out.ptr, '\0', 16);
 451                 req->out.ptr += 16;
 452
 453                 memcpy(req->out.ptr, blob.data, blob.length);
 454                 SCVAL(req->out.vwv+1, VWV(16), blob.length + 16);
 455                 req->out.ptr += blob.length;
 456         }
 457
 458         smbsrv_send_reply_nosign(req);
 459 }
 460
 461 /****************************************************************************
 462  Reply for the SMB2 2.001 protocol
 463 ****************************************************************************/
 464 static void reply_smb2(struct smbsrv_request *req, uint16_t choice)
 465 {
 466         struct smbsrv_connection *smb_conn = req->smb_conn;
 467         NTSTATUS status;
 468
 469         talloc_free(smb_conn->sessions.idtree_vuid);
 470         ZERO_STRUCT(smb_conn->sessions);
 471         talloc_free(smb_conn->smb_tcons.idtree_tid);
 472         ZERO_STRUCT(smb_conn->smb_tcons);
 473         ZERO_STRUCT(smb_conn->signing);
 474
 475         /* reply with a SMB2 packet */
 476         status = smbsrv_init_smb2_connection(smb_conn);
 477         if (!NT_STATUS_IS_OK(status)) {
 478                 smbsrv_terminate_connection(smb_conn, nt_errstr(status));
 479                 talloc_free(req);
 480                 return;
 481         }
 482         packet_set_callback(smb_conn->packet, smbsrv_recv_smb2_request);
 483         smb2srv_reply_smb_negprot(req);
 484         req = NULL;
 485 }
 486
 487 /* List of supported protocols, most desired first */
 488 static const struct {
 489         const char *proto_name;
 490         const char *short_name;
 491         void (*proto_reply_fn)(struct smbsrv_request *req, uint16_t choice);
 492         int protocol_level;
 493 } supported_protocols[] = {
 494         {"SMB 2.002",                   "SMB2",         reply_smb2,     PROTOCOL_SMB2_02},
 495         {"NT LANMAN 1.0",               "NT1",          reply_nt1,      PROTOCOL_NT1},
 496         {"NT LM 0.12",                  "NT1",          reply_nt1,      PROTOCOL_NT1},
 497         {"LANMAN2.1",                   "LANMAN2",      reply_lanman2,  PROTOCOL_LANMAN2},
 498         {"LM1.2X002",                   "LANMAN2",      reply_lanman2,  PROTOCOL_LANMAN2},
 499         {"Samba",                       "LANMAN2",      reply_lanman2,  PROTOCOL_LANMAN2},
 500         {"DOS LM1.2X002",               "LANMAN2",      reply_lanman2,  PROTOCOL_LANMAN2},
 501         {"Windows for Workgroups 3.1a", "LANMAN1",      reply_lanman1,  PROTOCOL_LANMAN1},
 502         {"LANMAN1.0",                   "LANMAN1",      reply_lanman1,  PROTOCOL_LANMAN1},
 503         {"MICROSOFT NETWORKS 3.0",      "LANMAN1",      reply_lanman1,  PROTOCOL_LANMAN1},
 504         {"MICROSOFT NETWORKS 1.03",     "COREPLUS",     reply_coreplus, PROTOCOL_COREPLUS},
 505         {"PC NETWORK PROGRAM 1.0",      "CORE",         reply_corep,    PROTOCOL_CORE},
 506         {NULL,NULL,NULL,0},
 507 };
 508
 509 /****************************************************************************
 510  Reply to a negprot.
 511 ****************************************************************************/
 512
 513 void smbsrv_reply_negprot(struct smbsrv_request *req)
 514 {
 515         int protocol;
 516         uint8_t *p;
 517         uint32_t protos_count = 0;
 518         const char **protos = NULL;
 519
 520         if (req->smb_conn->negotiate.done_negprot) {
 521                 smbsrv_terminate_connection(req->smb_conn, "multiple negprot's are not permitted");
 522                 return;
 523         }
 524         req->smb_conn->negotiate.done_negprot = true;
 525
 526         p = req->in.data;
 527         while (true) {
 528                 size_t len;
 529
 530                 protos = talloc_realloc(req, protos, const char *, protos_count + 1);
 531                 if (!protos) {
 532                         smbsrv_terminate_connection(req->smb_conn, nt_errstr(NT_STATUS_NO_MEMORY));
 533                         return;
 534                 }
 535                 protos[protos_count] = NULL;
 536                 len = req_pull_ascii4(&req->in.bufinfo, &protos[protos_count], p, STR_ASCII|STR_TERMINATE);
 537                 p += len;
 538                 if (len == 0 || !protos[protos_count]) break;
 539
 540                 DEBUG(5,("Requested protocol [%d][%s]\n", protos_count, protos[protos_count]));
 541                 protos_count++;
 542         }
 543
 544         /* Check for protocols, most desirable first */
 545         for (protocol = 0; supported_protocols[protocol].proto_name; protocol++) {
 546                 int i;
 547
 548                 if (supported_protocols[protocol].protocol_level > lpcfg_server_max_protocol(req->smb_conn->lp_ctx))
 549                         continue;
 550                 if (supported_protocols[protocol].protocol_level < lpcfg_server_min_protocol(req->smb_conn->lp_ctx))
 551                         continue;
 552
 553                 for (i = 0; i < protos_count; i++) {
 554                         if (strcmp(supported_protocols[protocol].proto_name, protos[i]) != 0) continue;
 555
 556                         supported_protocols[protocol].proto_reply_fn(req, i);
 557                         DEBUG(3,("Selected protocol [%d][%s]\n",
 558                                 i, supported_protocols[protocol].proto_name));
 559                         return;
 560                 }
 561         }
 562
 563         smbsrv_terminate_connection(req->smb_conn, "No protocol supported !");
 564 }