fs/cifs/connect.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2011
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  */
   8 #include <linux/fs.h>
   9 #include <linux/net.h>
  10 #include <linux/string.h>
  11 #include <linux/sched/mm.h>
  12 #include <linux/sched/signal.h>
  13 #include <linux/list.h>
  14 #include <linux/wait.h>
  15 #include <linux/slab.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/ctype.h>
  18 #include <linux/utsname.h>
  19 #include <linux/mempool.h>
  20 #include <linux/delay.h>
  21 #include <linux/completion.h>
  22 #include <linux/kthread.h>
  23 #include <linux/pagevec.h>
  24 #include <linux/freezer.h>
  25 #include <linux/namei.h>
  26 #include <linux/uuid.h>
  27 #include <linux/uaccess.h>
  28 #include <asm/processor.h>
  29 #include <linux/inet.h>
  30 #include <linux/module.h>
  31 #include <keys/user-type.h>
  32 #include <net/ipv6.h>
  33 #include <linux/parser.h>
  34 #include <linux/bvec.h>
  35 #include "cifspdu.h"
  36 #include "cifsglob.h"
  37 #include "cifsproto.h"
  38 #include "cifs_unicode.h"
  39 #include "cifs_debug.h"
  40 #include "cifs_fs_sb.h"
  41 #include "ntlmssp.h"
  42 #include "nterr.h"
  43 #include "rfc1002pdu.h"
  44 #include "fscache.h"
  45 #include "smb2proto.h"
  46 #include "smbdirect.h"
  47 #include "dns_resolve.h"
  48 #ifdef CONFIG_CIFS_DFS_UPCALL
  49 #include "dfs_cache.h"
  50 #endif
  51 #include "fs_context.h"
  52 #include "cifs_swn.h"
  53
  54 extern mempool_t *cifs_req_poolp;
  55 extern bool disable_legacy_dialects;
  56
  57 /* FIXME: should these be tunable? */
  58 #define TLINK_ERROR_EXPIRE      (1 * HZ)
  59 #define TLINK_IDLE_EXPIRE       (600 * HZ)
  60
  61 /* Drop the connection to not overload the server */
  62 #define NUM_STATUS_IO_TIMEOUT   5
  63
  64 static int ip_connect(struct TCP_Server_Info *server);
  65 static int generic_ip_connect(struct TCP_Server_Info *server);
  66 static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
  67 static void cifs_prune_tlinks(struct work_struct *work);
  68
  69 /*
  70  * Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may
  71  * get their ip addresses changed at some point.
  72  *
  73  * This should be called with server->srv_mutex held.
  74  */
  75 static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
  76 {
  77         int rc;
  78         int len;
  79         char *unc, *ipaddr = NULL;
  80         time64_t expiry, now;
  81         unsigned long ttl = SMB_DNS_RESOLVE_INTERVAL_DEFAULT;
  82
  83         if (!server->hostname)
  84                 return -EINVAL;
  85
  86         len = strlen(server->hostname) + 3;
  87
  88         unc = kmalloc(len, GFP_KERNEL);
  89         if (!unc) {
  90                 cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
  91                 return -ENOMEM;
  92         }
  93         scnprintf(unc, len, "\\\\%s", server->hostname);
  94
  95         rc = dns_resolve_server_name_to_ip(unc, &ipaddr, &expiry);
  96         kfree(unc);
  97
  98         if (rc < 0) {
  99                 cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",
 100                          __func__, server->hostname, rc);
 101                 goto requeue_resolve;
 102         }
 103
 104         spin_lock(&cifs_tcp_ses_lock);
 105         rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,
 106                                   strlen(ipaddr));
 107         spin_unlock(&cifs_tcp_ses_lock);
 108         kfree(ipaddr);
 109
 110         /* rc == 1 means success here */
 111         if (rc) {
 112                 now = ktime_get_real_seconds();
 113                 if (expiry && expiry > now)
 114                         /*
 115                          * To make sure we don't use the cached entry, retry 1s
 116                          * after expiry.
 117                          */
 118                         ttl = (expiry - now + 1);
 119         }
 120         rc = !rc ? -1 : 0;
 121
 122 requeue_resolve:
 123         cifs_dbg(FYI, "%s: next dns resolution scheduled for %lu seconds in the future\n",
 124                  __func__, ttl);
 125         mod_delayed_work(cifsiod_wq, &server->resolve, (ttl * HZ));
 126
 127         return rc;
 128 }
 129
 130
 131 static void cifs_resolve_server(struct work_struct *work)
 132 {
 133         int rc;
 134         struct TCP_Server_Info *server = container_of(work,
 135                                         struct TCP_Server_Info, resolve.work);
 136
 137         mutex_lock(&server->srv_mutex);
 138
 139         /*
 140          * Resolve the hostname again to make sure that IP address is up-to-date.
 141          */
 142         rc = reconn_set_ipaddr_from_hostname(server);
 143         if (rc) {
 144                 cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
 145                                 __func__, rc);
 146         }
 147
 148         mutex_unlock(&server->srv_mutex);
 149 }
 150
 151 #ifdef CONFIG_CIFS_DFS_UPCALL
 152 /* These functions must be called with server->srv_mutex held */
 153 static void reconn_set_next_dfs_target(struct TCP_Server_Info *server,
 154                                        struct cifs_sb_info *cifs_sb,
 155                                        struct dfs_cache_tgt_list *tgt_list,
 156                                        struct dfs_cache_tgt_iterator **tgt_it)
 157 {
 158         const char *name;
 159         int rc;
 160
 161         if (!cifs_sb || !cifs_sb->origin_fullpath)
 162                 return;
 163
 164         if (!*tgt_it) {
 165                 *tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
 166         } else {
 167                 *tgt_it = dfs_cache_get_next_tgt(tgt_list, *tgt_it);
 168                 if (!*tgt_it)
 169                         *tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
 170         }
 171
 172         cifs_dbg(FYI, "%s: UNC: %s\n", __func__, cifs_sb->origin_fullpath);
 173
 174         name = dfs_cache_get_tgt_name(*tgt_it);
 175
 176         kfree(server->hostname);
 177
 178         server->hostname = extract_hostname(name);
 179         if (IS_ERR(server->hostname)) {
 180                 cifs_dbg(FYI,
 181                          "%s: failed to extract hostname from target: %ld\n",
 182                          __func__, PTR_ERR(server->hostname));
 183                 return;
 184         }
 185
 186         rc = reconn_set_ipaddr_from_hostname(server);
 187         if (rc) {
 188                 cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
 189                          __func__, rc);
 190         }
 191 }
 192
 193 static inline int reconn_setup_dfs_targets(struct cifs_sb_info *cifs_sb,
 194                                            struct dfs_cache_tgt_list *tl)
 195 {
 196         if (!cifs_sb->origin_fullpath)
 197                 return -EOPNOTSUPP;
 198         return dfs_cache_noreq_find(cifs_sb->origin_fullpath + 1, NULL, tl);
 199 }
 200 #endif
 201
 202 /*
 203  * cifs tcp session reconnection
 204  *
 205  * mark tcp session as reconnecting so temporarily locked
 206  * mark all smb sessions as reconnecting for tcp session
 207  * reconnect tcp session
 208  * wake up waiters on reconnection? - (not needed currently)
 209  */
 210 int
 211 cifs_reconnect(struct TCP_Server_Info *server)
 212 {
 213         int rc = 0;
 214         struct list_head *tmp, *tmp2;
 215         struct cifs_ses *ses;
 216         struct cifs_tcon *tcon;
 217         struct mid_q_entry *mid_entry;
 218         struct list_head retry_list;
 219 #ifdef CONFIG_CIFS_DFS_UPCALL
 220         struct super_block *sb = NULL;
 221         struct cifs_sb_info *cifs_sb = NULL;
 222         struct dfs_cache_tgt_list tgt_list = DFS_CACHE_TGT_LIST_INIT(tgt_list);
 223         struct dfs_cache_tgt_iterator *tgt_it = NULL;
 224 #endif
 225
 226         spin_lock(&GlobalMid_Lock);
 227         server->nr_targets = 1;
 228 #ifdef CONFIG_CIFS_DFS_UPCALL
 229         spin_unlock(&GlobalMid_Lock);
 230         sb = cifs_get_tcp_super(server);
 231         if (IS_ERR(sb)) {
 232                 rc = PTR_ERR(sb);
 233                 cifs_dbg(FYI, "%s: will not do DFS failover: rc = %d\n",
 234                          __func__, rc);
 235                 sb = NULL;
 236         } else {
 237                 cifs_sb = CIFS_SB(sb);
 238                 rc = reconn_setup_dfs_targets(cifs_sb, &tgt_list);
 239                 if (rc) {
 240                         cifs_sb = NULL;
 241                         if (rc != -EOPNOTSUPP) {
 242                                 cifs_server_dbg(VFS, "%s: no target servers for DFS failover\n",
 243                                                 __func__);
 244                         }
 245                 } else {
 246                         server->nr_targets = dfs_cache_get_nr_tgts(&tgt_list);
 247                 }
 248         }
 249         cifs_dbg(FYI, "%s: will retry %d target(s)\n", __func__,
 250                  server->nr_targets);
 251         spin_lock(&GlobalMid_Lock);
 252 #endif
 253         if (server->tcpStatus == CifsExiting) {
 254                 /* the demux thread will exit normally
 255                 next time through the loop */
 256                 spin_unlock(&GlobalMid_Lock);
 257 #ifdef CONFIG_CIFS_DFS_UPCALL
 258                 dfs_cache_free_tgts(&tgt_list);
 259                 cifs_put_tcp_super(sb);
 260 #endif
 261                 wake_up(&server->response_q);
 262                 return rc;
 263         } else
 264                 server->tcpStatus = CifsNeedReconnect;
 265         spin_unlock(&GlobalMid_Lock);
 266         server->maxBuf = 0;
 267         server->max_read = 0;
 268
 269         cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
 270         trace_smb3_reconnect(server->CurrentMid, server->conn_id, server->hostname);
 271
 272         /* before reconnecting the tcp session, mark the smb session (uid)
 273                 and the tid bad so they are not used until reconnected */
 274         cifs_dbg(FYI, "%s: marking sessions and tcons for reconnect\n",
 275                  __func__);
 276         spin_lock(&cifs_tcp_ses_lock);
 277         list_for_each(tmp, &server->smb_ses_list) {
 278                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 279                 ses->need_reconnect = true;
 280                 list_for_each(tmp2, &ses->tcon_list) {
 281                         tcon = list_entry(tmp2, struct cifs_tcon, tcon_list);
 282                         tcon->need_reconnect = true;
 283                 }
 284                 if (ses->tcon_ipc)
 285                         ses->tcon_ipc->need_reconnect = true;
 286         }
 287         spin_unlock(&cifs_tcp_ses_lock);
 288
 289         /* do not want to be sending data on a socket we are freeing */
 290         cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
 291         mutex_lock(&server->srv_mutex);
 292         if (server->ssocket) {
 293                 cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n",
 294                          server->ssocket->state, server->ssocket->flags);
 295                 kernel_sock_shutdown(server->ssocket, SHUT_WR);
 296                 cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n",
 297                          server->ssocket->state, server->ssocket->flags);
 298                 sock_release(server->ssocket);
 299                 server->ssocket = NULL;
 300         }
 301         server->sequence_number = 0;
 302         server->session_estab = false;
 303         kfree(server->session_key.response);
 304         server->session_key.response = NULL;
 305         server->session_key.len = 0;
 306         server->lstrp = jiffies;
 307
 308         /* mark submitted MIDs for retry and issue callback */
 309         INIT_LIST_HEAD(&retry_list);
 310         cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
 311         spin_lock(&GlobalMid_Lock);
 312         list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
 313                 mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 314                 kref_get(&mid_entry->refcount);
 315                 if (mid_entry->mid_state == MID_REQUEST_SUBMITTED)
 316                         mid_entry->mid_state = MID_RETRY_NEEDED;
 317                 list_move(&mid_entry->qhead, &retry_list);
 318                 mid_entry->mid_flags |= MID_DELETED;
 319         }
 320         spin_unlock(&GlobalMid_Lock);
 321         mutex_unlock(&server->srv_mutex);
 322
 323         cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
 324         list_for_each_safe(tmp, tmp2, &retry_list) {
 325                 mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 326                 list_del_init(&mid_entry->qhead);
 327                 mid_entry->callback(mid_entry);
 328                 cifs_mid_q_entry_release(mid_entry);
 329         }
 330
 331         if (cifs_rdma_enabled(server)) {
 332                 mutex_lock(&server->srv_mutex);
 333                 smbd_destroy(server);
 334                 mutex_unlock(&server->srv_mutex);
 335         }
 336
 337         do {
 338                 try_to_freeze();
 339
 340                 mutex_lock(&server->srv_mutex);
 341
 342
 343                 if (!cifs_swn_set_server_dstaddr(server)) {
 344 #ifdef CONFIG_CIFS_DFS_UPCALL
 345                 if (cifs_sb && cifs_sb->origin_fullpath)
 346                         /*
 347                          * Set up next DFS target server (if any) for reconnect. If DFS
 348                          * feature is disabled, then we will retry last server we
 349                          * connected to before.
 350                          */
 351                         reconn_set_next_dfs_target(server, cifs_sb, &tgt_list, &tgt_it);
 352                 else {
 353 #endif
 354                         /*
 355                          * Resolve the hostname again to make sure that IP address is up-to-date.
 356                          */
 357                         rc = reconn_set_ipaddr_from_hostname(server);
 358                         if (rc) {
 359                                 cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
 360                                                 __func__, rc);
 361                         }
 362
 363 #ifdef CONFIG_CIFS_DFS_UPCALL
 364                 }
 365 #endif
 366
 367
 368                 }
 369
 370                 if (cifs_rdma_enabled(server))
 371                         rc = smbd_reconnect(server);
 372                 else
 373                         rc = generic_ip_connect(server);
 374                 if (rc) {
 375                         cifs_dbg(FYI, "reconnect error %d\n", rc);
 376                         mutex_unlock(&server->srv_mutex);
 377                         msleep(3000);
 378                 } else {
 379                         atomic_inc(&tcpSesReconnectCount);
 380                         set_credits(server, 1);
 381                         spin_lock(&GlobalMid_Lock);
 382                         if (server->tcpStatus != CifsExiting)
 383                                 server->tcpStatus = CifsNeedNegotiate;
 384                         spin_unlock(&GlobalMid_Lock);
 385                         cifs_swn_reset_server_dstaddr(server);
 386                         mutex_unlock(&server->srv_mutex);
 387                 }
 388         } while (server->tcpStatus == CifsNeedReconnect);
 389
 390 #ifdef CONFIG_CIFS_DFS_UPCALL
 391         if (tgt_it) {
 392                 rc = dfs_cache_noreq_update_tgthint(cifs_sb->origin_fullpath + 1,
 393                                                     tgt_it);
 394                 if (rc) {
 395                         cifs_server_dbg(VFS, "%s: failed to update DFS target hint: rc = %d\n",
 396                                  __func__, rc);
 397                 }
 398                 dfs_cache_free_tgts(&tgt_list);
 399         }
 400
 401         cifs_put_tcp_super(sb);
 402 #endif
 403         if (server->tcpStatus == CifsNeedNegotiate)
 404                 mod_delayed_work(cifsiod_wq, &server->echo, 0);
 405
 406         wake_up(&server->response_q);
 407         return rc;
 408 }
 409
 410 static void
 411 cifs_echo_request(struct work_struct *work)
 412 {
 413         int rc;
 414         struct TCP_Server_Info *server = container_of(work,
 415                                         struct TCP_Server_Info, echo.work);
 416
 417         /*
 418          * We cannot send an echo if it is disabled.
 419          * Also, no need to ping if we got a response recently.
 420          */
 421
 422         if (server->tcpStatus == CifsNeedReconnect ||
 423             server->tcpStatus == CifsExiting ||
 424             server->tcpStatus == CifsNew ||
 425             (server->ops->can_echo && !server->ops->can_echo(server)) ||
 426             time_before(jiffies, server->lstrp + server->echo_interval - HZ))
 427                 goto requeue_echo;
 428
 429         rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
 430         if (rc)
 431                 cifs_dbg(FYI, "Unable to send echo request to server: %s\n",
 432                          server->hostname);
 433
 434         /* Check witness registrations */
 435         cifs_swn_check();
 436
 437 requeue_echo:
 438         queue_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
 439 }
 440
 441 static bool
 442 allocate_buffers(struct TCP_Server_Info *server)
 443 {
 444         if (!server->bigbuf) {
 445                 server->bigbuf = (char *)cifs_buf_get();
 446                 if (!server->bigbuf) {
 447                         cifs_server_dbg(VFS, "No memory for large SMB response\n");
 448                         msleep(3000);
 449                         /* retry will check if exiting */
 450                         return false;
 451                 }
 452         } else if (server->large_buf) {
 453                 /* we are reusing a dirty large buf, clear its start */
 454                 memset(server->bigbuf, 0, HEADER_SIZE(server));
 455         }
 456
 457         if (!server->smallbuf) {
 458                 server->smallbuf = (char *)cifs_small_buf_get();
 459                 if (!server->smallbuf) {
 460                         cifs_server_dbg(VFS, "No memory for SMB response\n");
 461                         msleep(1000);
 462                         /* retry will check if exiting */
 463                         return false;
 464                 }
 465                 /* beginning of smb buffer is cleared in our buf_get */
 466         } else {
 467                 /* if existing small buf clear beginning */
 468                 memset(server->smallbuf, 0, HEADER_SIZE(server));
 469         }
 470
 471         return true;
 472 }
 473
 474 static bool
 475 server_unresponsive(struct TCP_Server_Info *server)
 476 {
 477         /*
 478          * We need to wait 3 echo intervals to make sure we handle such
 479          * situations right:
 480          * 1s  client sends a normal SMB request
 481          * 2s  client gets a response
 482          * 30s echo workqueue job pops, and decides we got a response recently
 483          *     and don't need to send another
 484          * ...
 485          * 65s kernel_recvmsg times out, and we see that we haven't gotten
 486          *     a response in >60s.
 487          */
 488         if ((server->tcpStatus == CifsGood ||
 489             server->tcpStatus == CifsNeedNegotiate) &&
 490             (!server->ops->can_echo || server->ops->can_echo(server)) &&
 491             time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
 492                 cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
 493                          (3 * server->echo_interval) / HZ);
 494                 cifs_reconnect(server);
 495                 return true;
 496         }
 497
 498         return false;
 499 }
 500
 501 static inline bool
 502 zero_credits(struct TCP_Server_Info *server)
 503 {
 504         int val;
 505
 506         spin_lock(&server->req_lock);
 507         val = server->credits + server->echo_credits + server->oplock_credits;
 508         if (server->in_flight == 0 && val == 0) {
 509                 spin_unlock(&server->req_lock);
 510                 return true;
 511         }
 512         spin_unlock(&server->req_lock);
 513         return false;
 514 }
 515
 516 static int
 517 cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
 518 {
 519         int length = 0;
 520         int total_read;
 521
 522         smb_msg->msg_control = NULL;
 523         smb_msg->msg_controllen = 0;
 524
 525         for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
 526                 try_to_freeze();
 527
 528                 /* reconnect if no credits and no requests in flight */
 529                 if (zero_credits(server)) {
 530                         cifs_reconnect(server);
 531                         return -ECONNABORTED;
 532                 }
 533
 534                 if (server_unresponsive(server))
 535                         return -ECONNABORTED;
 536                 if (cifs_rdma_enabled(server) && server->smbd_conn)
 537                         length = smbd_recv(server->smbd_conn, smb_msg);
 538                 else
 539                         length = sock_recvmsg(server->ssocket, smb_msg, 0);
 540
 541                 if (server->tcpStatus == CifsExiting)
 542                         return -ESHUTDOWN;
 543
 544                 if (server->tcpStatus == CifsNeedReconnect) {
 545                         cifs_reconnect(server);
 546                         return -ECONNABORTED;
 547                 }
 548
 549                 if (length == -ERESTARTSYS ||
 550                     length == -EAGAIN ||
 551                     length == -EINTR) {
 552                         /*
 553                          * Minimum sleep to prevent looping, allowing socket
 554                          * to clear and app threads to set tcpStatus
 555                          * CifsNeedReconnect if server hung.
 556                          */
 557                         usleep_range(1000, 2000);
 558                         length = 0;
 559                         continue;
 560                 }
 561
 562                 if (length <= 0) {
 563                         cifs_dbg(FYI, "Received no data or error: %d\n", length);
 564                         cifs_reconnect(server);
 565                         return -ECONNABORTED;
 566                 }
 567         }
 568         return total_read;
 569 }
 570
 571 int
 572 cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
 573                       unsigned int to_read)
 574 {
 575         struct msghdr smb_msg;
 576         struct kvec iov = {.iov_base = buf, .iov_len = to_read};
 577         iov_iter_kvec(&smb_msg.msg_iter, READ, &iov, 1, to_read);
 578
 579         return cifs_readv_from_socket(server, &smb_msg);
 580 }
 581
 582 ssize_t
 583 cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
 584 {
 585         struct msghdr smb_msg;
 586
 587         /*
 588          *  iov_iter_discard already sets smb_msg.type and count and iov_offset
 589          *  and cifs_readv_from_socket sets msg_control and msg_controllen
 590          *  so little to initialize in struct msghdr
 591          */
 592         smb_msg.msg_name = NULL;
 593         smb_msg.msg_namelen = 0;
 594         iov_iter_discard(&smb_msg.msg_iter, READ, to_read);
 595
 596         return cifs_readv_from_socket(server, &smb_msg);
 597 }
 598
 599 int
 600 cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
 601         unsigned int page_offset, unsigned int to_read)
 602 {
 603         struct msghdr smb_msg;
 604         struct bio_vec bv = {
 605                 .bv_page = page, .bv_len = to_read, .bv_offset = page_offset};
 606         iov_iter_bvec(&smb_msg.msg_iter, READ, &bv, 1, to_read);
 607         return cifs_readv_from_socket(server, &smb_msg);
 608 }
 609
 610 static bool
 611 is_smb_response(struct TCP_Server_Info *server, unsigned char type)
 612 {
 613         /*
 614          * The first byte big endian of the length field,
 615          * is actually not part of the length but the type
 616          * with the most common, zero, as regular data.
 617          */
 618         switch (type) {
 619         case RFC1002_SESSION_MESSAGE:
 620                 /* Regular SMB response */
 621                 return true;
 622         case RFC1002_SESSION_KEEP_ALIVE:
 623                 cifs_dbg(FYI, "RFC 1002 session keep alive\n");
 624                 break;
 625         case RFC1002_POSITIVE_SESSION_RESPONSE:
 626                 cifs_dbg(FYI, "RFC 1002 positive session response\n");
 627                 break;
 628         case RFC1002_NEGATIVE_SESSION_RESPONSE:
 629                 /*
 630                  * We get this from Windows 98 instead of an error on
 631                  * SMB negprot response.
 632                  */
 633                 cifs_dbg(FYI, "RFC 1002 negative session response\n");
 634                 /* give server a second to clean up */
 635                 msleep(1000);
 636                 /*
 637                  * Always try 445 first on reconnect since we get NACK
 638                  * on some if we ever connected to port 139 (the NACK
 639                  * is since we do not begin with RFC1001 session
 640                  * initialize frame).
 641                  */
 642                 cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
 643                 cifs_reconnect(server);
 644                 break;
 645         default:
 646                 cifs_server_dbg(VFS, "RFC 1002 unknown response type 0x%x\n", type);
 647                 cifs_reconnect(server);
 648         }
 649
 650         return false;
 651 }
 652
 653 void
 654 dequeue_mid(struct mid_q_entry *mid, bool malformed)
 655 {
 656 #ifdef CONFIG_CIFS_STATS2
 657         mid->when_received = jiffies;
 658 #endif
 659         spin_lock(&GlobalMid_Lock);
 660         if (!malformed)
 661                 mid->mid_state = MID_RESPONSE_RECEIVED;
 662         else
 663                 mid->mid_state = MID_RESPONSE_MALFORMED;
 664         /*
 665          * Trying to handle/dequeue a mid after the send_recv()
 666          * function has finished processing it is a bug.
 667          */
 668         if (mid->mid_flags & MID_DELETED)
 669                 pr_warn_once("trying to dequeue a deleted mid\n");
 670         else {
 671                 list_del_init(&mid->qhead);
 672                 mid->mid_flags |= MID_DELETED;
 673         }
 674         spin_unlock(&GlobalMid_Lock);
 675 }
 676
 677 static unsigned int
 678 smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
 679 {
 680         struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
 681
 682         /*
 683          * SMB1 does not use credits.
 684          */
 685         if (server->vals->header_preamble_size)
 686                 return 0;
 687
 688         return le16_to_cpu(shdr->CreditRequest);
 689 }
 690
 691 static void
 692 handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 693            char *buf, int malformed)
 694 {
 695         if (server->ops->check_trans2 &&
 696             server->ops->check_trans2(mid, server, buf, malformed))
 697                 return;
 698         mid->credits_received = smb2_get_credits_from_hdr(buf, server);
 699         mid->resp_buf = buf;
 700         mid->large_buf = server->large_buf;
 701         /* Was previous buf put in mpx struct for multi-rsp? */
 702         if (!mid->multiRsp) {
 703                 /* smb buffer will be freed by user thread */
 704                 if (server->large_buf)
 705                         server->bigbuf = NULL;
 706                 else
 707                         server->smallbuf = NULL;
 708         }
 709         dequeue_mid(mid, malformed);
 710 }
 711
 712 static void clean_demultiplex_info(struct TCP_Server_Info *server)
 713 {
 714         int length;
 715
 716         /* take it off the list, if it's not already */
 717         spin_lock(&cifs_tcp_ses_lock);
 718         list_del_init(&server->tcp_ses_list);
 719         spin_unlock(&cifs_tcp_ses_lock);
 720
 721         cancel_delayed_work_sync(&server->echo);
 722         cancel_delayed_work_sync(&server->resolve);
 723
 724         spin_lock(&GlobalMid_Lock);
 725         server->tcpStatus = CifsExiting;
 726         spin_unlock(&GlobalMid_Lock);
 727         wake_up_all(&server->response_q);
 728
 729         /* check if we have blocked requests that need to free */
 730         spin_lock(&server->req_lock);
 731         if (server->credits <= 0)
 732                 server->credits = 1;
 733         spin_unlock(&server->req_lock);
 734         /*
 735          * Although there should not be any requests blocked on this queue it
 736          * can not hurt to be paranoid and try to wake up requests that may
 737          * haven been blocked when more than 50 at time were on the wire to the
 738          * same server - they now will see the session is in exit state and get
 739          * out of SendReceive.
 740          */
 741         wake_up_all(&server->request_q);
 742         /* give those requests time to exit */
 743         msleep(125);
 744         if (cifs_rdma_enabled(server))
 745                 smbd_destroy(server);
 746         if (server->ssocket) {
 747                 sock_release(server->ssocket);
 748                 server->ssocket = NULL;
 749         }
 750
 751         if (!list_empty(&server->pending_mid_q)) {
 752                 struct list_head dispose_list;
 753                 struct mid_q_entry *mid_entry;
 754                 struct list_head *tmp, *tmp2;
 755
 756                 INIT_LIST_HEAD(&dispose_list);
 757                 spin_lock(&GlobalMid_Lock);
 758                 list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
 759                         mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 760                         cifs_dbg(FYI, "Clearing mid %llu\n", mid_entry->mid);
 761                         kref_get(&mid_entry->refcount);
 762                         mid_entry->mid_state = MID_SHUTDOWN;
 763                         list_move(&mid_entry->qhead, &dispose_list);
 764                         mid_entry->mid_flags |= MID_DELETED;
 765                 }
 766                 spin_unlock(&GlobalMid_Lock);
 767
 768                 /* now walk dispose list and issue callbacks */
 769                 list_for_each_safe(tmp, tmp2, &dispose_list) {
 770                         mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 771                         cifs_dbg(FYI, "Callback mid %llu\n", mid_entry->mid);
 772                         list_del_init(&mid_entry->qhead);
 773                         mid_entry->callback(mid_entry);
 774                         cifs_mid_q_entry_release(mid_entry);
 775                 }
 776                 /* 1/8th of sec is more than enough time for them to exit */
 777                 msleep(125);
 778         }
 779
 780         if (!list_empty(&server->pending_mid_q)) {
 781                 /*
 782                  * mpx threads have not exited yet give them at least the smb
 783                  * send timeout time for long ops.
 784                  *
 785                  * Due to delays on oplock break requests, we need to wait at
 786                  * least 45 seconds before giving up on a request getting a
 787                  * response and going ahead and killing cifsd.
 788                  */
 789                 cifs_dbg(FYI, "Wait for exit from demultiplex thread\n");
 790                 msleep(46000);
 791                 /*
 792                  * If threads still have not exited they are probably never
 793                  * coming home not much else we can do but free the memory.
 794                  */
 795         }
 796
 797         kfree(server);
 798
 799         length = atomic_dec_return(&tcpSesAllocCount);
 800         if (length > 0)
 801                 mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
 802 }
 803
 804 static int
 805 standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 806 {
 807         int length;
 808         char *buf = server->smallbuf;
 809         unsigned int pdu_length = server->pdu_size;
 810
 811         /* make sure this will fit in a large buffer */
 812         if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
 813                 server->vals->header_preamble_size) {
 814                 cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
 815                 cifs_reconnect(server);
 816                 return -ECONNABORTED;
 817         }
 818
 819         /* switch to large buffer if too big for a small one */
 820         if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
 821                 server->large_buf = true;
 822                 memcpy(server->bigbuf, buf, server->total_read);
 823                 buf = server->bigbuf;
 824         }
 825
 826         /* now read the rest */
 827         length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
 828                                        pdu_length - HEADER_SIZE(server) + 1
 829                                        + server->vals->header_preamble_size);
 830
 831         if (length < 0)
 832                 return length;
 833         server->total_read += length;
 834
 835         dump_smb(buf, server->total_read);
 836
 837         return cifs_handle_standard(server, mid);
 838 }
 839
 840 int
 841 cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 842 {
 843         char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
 844         int length;
 845
 846         /*
 847          * We know that we received enough to get to the MID as we
 848          * checked the pdu_length earlier. Now check to see
 849          * if the rest of the header is OK. We borrow the length
 850          * var for the rest of the loop to avoid a new stack var.
 851          *
 852          * 48 bytes is enough to display the header and a little bit
 853          * into the payload for debugging purposes.
 854          */
 855         length = server->ops->check_message(buf, server->total_read, server);
 856         if (length != 0)
 857                 cifs_dump_mem("Bad SMB: ", buf,
 858                         min_t(unsigned int, server->total_read, 48));
 859
 860         if (server->ops->is_session_expired &&
 861             server->ops->is_session_expired(buf)) {
 862                 cifs_reconnect(server);
 863                 return -1;
 864         }
 865
 866         if (server->ops->is_status_pending &&
 867             server->ops->is_status_pending(buf, server))
 868                 return -1;
 869
 870         if (!mid)
 871                 return length;
 872
 873         handle_mid(mid, server, buf, length);
 874         return 0;
 875 }
 876
 877 static void
 878 smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
 879 {
 880         struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
 881         int scredits, in_flight;
 882
 883         /*
 884          * SMB1 does not use credits.
 885          */
 886         if (server->vals->header_preamble_size)
 887                 return;
 888
 889         if (shdr->CreditRequest) {
 890                 spin_lock(&server->req_lock);
 891                 server->credits += le16_to_cpu(shdr->CreditRequest);
 892                 scredits = server->credits;
 893                 in_flight = server->in_flight;
 894                 spin_unlock(&server->req_lock);
 895                 wake_up(&server->request_q);
 896
 897                 trace_smb3_add_credits(server->CurrentMid,
 898                                 server->conn_id, server->hostname, scredits,
 899                                 le16_to_cpu(shdr->CreditRequest), in_flight);
 900                 cifs_server_dbg(FYI, "%s: added %u credits total=%d\n",
 901                                 __func__, le16_to_cpu(shdr->CreditRequest),
 902                                 scredits);
 903         }
 904 }
 905
 906
 907 static int
 908 cifs_demultiplex_thread(void *p)
 909 {
 910         int i, num_mids, length;
 911         struct TCP_Server_Info *server = p;
 912         unsigned int pdu_length;
 913         unsigned int next_offset;
 914         char *buf = NULL;
 915         struct task_struct *task_to_wake = NULL;
 916         struct mid_q_entry *mids[MAX_COMPOUND];
 917         char *bufs[MAX_COMPOUND];
 918         unsigned int noreclaim_flag, num_io_timeout = 0;
 919
 920         noreclaim_flag = memalloc_noreclaim_save();
 921         cifs_dbg(FYI, "Demultiplex PID: %d\n", task_pid_nr(current));
 922
 923         length = atomic_inc_return(&tcpSesAllocCount);
 924         if (length > 1)
 925                 mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
 926
 927         set_freezable();
 928         allow_kernel_signal(SIGKILL);
 929         while (server->tcpStatus != CifsExiting) {
 930                 if (try_to_freeze())
 931                         continue;
 932
 933                 if (!allocate_buffers(server))
 934                         continue;
 935
 936                 server->large_buf = false;
 937                 buf = server->smallbuf;
 938                 pdu_length = 4; /* enough to get RFC1001 header */
 939
 940                 length = cifs_read_from_socket(server, buf, pdu_length);
 941                 if (length < 0)
 942                         continue;
 943
 944                 if (server->vals->header_preamble_size == 0)
 945                         server->total_read = 0;
 946                 else
 947                         server->total_read = length;
 948
 949                 /*
 950                  * The right amount was read from socket - 4 bytes,
 951                  * so we can now interpret the length field.
 952                  */
 953                 pdu_length = get_rfc1002_length(buf);
 954
 955                 cifs_dbg(FYI, "RFC1002 header 0x%x\n", pdu_length);
 956                 if (!is_smb_response(server, buf[0]))
 957                         continue;
 958 next_pdu:
 959                 server->pdu_size = pdu_length;
 960
 961                 /* make sure we have enough to get to the MID */
 962                 if (server->pdu_size < HEADER_SIZE(server) - 1 -
 963                     server->vals->header_preamble_size) {
 964                         cifs_server_dbg(VFS, "SMB response too short (%u bytes)\n",
 965                                  server->pdu_size);
 966                         cifs_reconnect(server);
 967                         continue;
 968                 }
 969
 970                 /* read down to the MID */
 971                 length = cifs_read_from_socket(server,
 972                              buf + server->vals->header_preamble_size,
 973                              HEADER_SIZE(server) - 1
 974                              - server->vals->header_preamble_size);
 975                 if (length < 0)
 976                         continue;
 977                 server->total_read += length;
 978
 979                 if (server->ops->next_header) {
 980                         next_offset = server->ops->next_header(buf);
 981                         if (next_offset)
 982                                 server->pdu_size = next_offset;
 983                 }
 984
 985                 memset(mids, 0, sizeof(mids));
 986                 memset(bufs, 0, sizeof(bufs));
 987                 num_mids = 0;
 988
 989                 if (server->ops->is_transform_hdr &&
 990                     server->ops->receive_transform &&
 991                     server->ops->is_transform_hdr(buf)) {
 992                         length = server->ops->receive_transform(server,
 993                                                                 mids,
 994                                                                 bufs,
 995                                                                 &num_mids);
 996                 } else {
 997                         mids[0] = server->ops->find_mid(server, buf);
 998                         bufs[0] = buf;
 999                         num_mids = 1;
1000
1001                         if (!mids[0] || !mids[0]->receive)
1002                                 length = standard_receive3(server, mids[0]);
1003                         else
1004                                 length = mids[0]->receive(server, mids[0]);
1005                 }
1006
1007                 if (length < 0) {
1008                         for (i = 0; i < num_mids; i++)
1009                                 if (mids[i])
1010                                         cifs_mid_q_entry_release(mids[i]);
1011                         continue;
1012                 }
1013
1014                 if (server->ops->is_status_io_timeout &&
1015                     server->ops->is_status_io_timeout(buf)) {
1016                         num_io_timeout++;
1017                         if (num_io_timeout > NUM_STATUS_IO_TIMEOUT) {
1018                                 cifs_reconnect(server);
1019                                 num_io_timeout = 0;
1020                                 continue;
1021                         }
1022                 }
1023
1024                 server->lstrp = jiffies;
1025
1026                 for (i = 0; i < num_mids; i++) {
1027                         if (mids[i] != NULL) {
1028                                 mids[i]->resp_buf_size = server->pdu_size;
1029
1030                                 if (bufs[i] && server->ops->is_network_name_deleted)
1031                                         server->ops->is_network_name_deleted(bufs[i],
1032                                                                         server);
1033
1034                                 if (!mids[i]->multiRsp || mids[i]->multiEnd)
1035                                         mids[i]->callback(mids[i]);
1036
1037                                 cifs_mid_q_entry_release(mids[i]);
1038                         } else if (server->ops->is_oplock_break &&
1039                                    server->ops->is_oplock_break(bufs[i],
1040                                                                 server)) {
1041                                 smb2_add_credits_from_hdr(bufs[i], server);
1042                                 cifs_dbg(FYI, "Received oplock break\n");
1043                         } else {
1044                                 cifs_server_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n",
1045                                                 atomic_read(&midCount));
1046                                 cifs_dump_mem("Received Data is: ", bufs[i],
1047                                               HEADER_SIZE(server));
1048                                 smb2_add_credits_from_hdr(bufs[i], server);
1049 #ifdef CONFIG_CIFS_DEBUG2
1050                                 if (server->ops->dump_detail)
1051                                         server->ops->dump_detail(bufs[i],
1052                                                                  server);
1053                                 cifs_dump_mids(server);
1054 #endif /* CIFS_DEBUG2 */
1055                         }
1056                 }
1057
1058                 if (pdu_length > server->pdu_size) {
1059                         if (!allocate_buffers(server))
1060                                 continue;
1061                         pdu_length -= server->pdu_size;
1062                         server->total_read = 0;
1063                         server->large_buf = false;
1064                         buf = server->smallbuf;
1065                         goto next_pdu;
1066                 }
1067         } /* end while !EXITING */
1068
1069         /* buffer usually freed in free_mid - need to free it here on exit */
1070         cifs_buf_release(server->bigbuf);
1071         if (server->smallbuf) /* no sense logging a debug message if NULL */
1072                 cifs_small_buf_release(server->smallbuf);
1073
1074         task_to_wake = xchg(&server->tsk, NULL);
1075         clean_demultiplex_info(server);
1076
1077         /* if server->tsk was NULL then wait for a signal before exiting */
1078         if (!task_to_wake) {
1079                 set_current_state(TASK_INTERRUPTIBLE);
1080                 while (!signal_pending(current)) {
1081                         schedule();
1082                         set_current_state(TASK_INTERRUPTIBLE);
1083                 }
1084                 set_current_state(TASK_RUNNING);
1085         }
1086
1087         memalloc_noreclaim_restore(noreclaim_flag);
1088         module_put_and_exit(0);
1089 }
1090
1091 /*
1092  * Returns true if srcaddr isn't specified and rhs isn't specified, or
1093  * if srcaddr is specified and matches the IP address of the rhs argument
1094  */
1095 bool
1096 cifs_match_ipaddr(struct sockaddr *srcaddr, struct sockaddr *rhs)
1097 {
1098         switch (srcaddr->sa_family) {
1099         case AF_UNSPEC:
1100                 return (rhs->sa_family == AF_UNSPEC);
1101         case AF_INET: {
1102                 struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
1103                 struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
1104                 return (saddr4->sin_addr.s_addr == vaddr4->sin_addr.s_addr);
1105         }
1106         case AF_INET6: {
1107                 struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
1108                 struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
1109                 return ipv6_addr_equal(&saddr6->sin6_addr, &vaddr6->sin6_addr);
1110         }
1111         default:
1112                 WARN_ON(1);
1113                 return false; /* don't expect to be here */
1114         }
1115 }
1116
1117 /*
1118  * If no port is specified in addr structure, we try to match with 445 port
1119  * and if it fails - with 139 ports. It should be called only if address
1120  * families of server and addr are equal.
1121  */
1122 static bool
1123 match_port(struct TCP_Server_Info *server, struct sockaddr *addr)
1124 {
1125         __be16 port, *sport;
1126
1127         /* SMBDirect manages its own ports, don't match it here */
1128         if (server->rdma)
1129                 return true;
1130
1131         switch (addr->sa_family) {
1132         case AF_INET:
1133                 sport = &((struct sockaddr_in *) &server->dstaddr)->sin_port;
1134                 port = ((struct sockaddr_in *) addr)->sin_port;
1135                 break;
1136         case AF_INET6:
1137                 sport = &((struct sockaddr_in6 *) &server->dstaddr)->sin6_port;
1138                 port = ((struct sockaddr_in6 *) addr)->sin6_port;
1139                 break;
1140         default:
1141                 WARN_ON(1);
1142                 return false;
1143         }
1144
1145         if (!port) {
1146                 port = htons(CIFS_PORT);
1147                 if (port == *sport)
1148                         return true;
1149
1150                 port = htons(RFC1001_PORT);
1151         }
1152
1153         return port == *sport;
1154 }
1155
1156 static bool
1157 match_address(struct TCP_Server_Info *server, struct sockaddr *addr,
1158               struct sockaddr *srcaddr)
1159 {
1160         switch (addr->sa_family) {
1161         case AF_INET: {
1162                 struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
1163                 struct sockaddr_in *srv_addr4 =
1164                                         (struct sockaddr_in *)&server->dstaddr;
1165
1166                 if (addr4->sin_addr.s_addr != srv_addr4->sin_addr.s_addr)
1167                         return false;
1168                 break;
1169         }
1170         case AF_INET6: {
1171                 struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
1172                 struct sockaddr_in6 *srv_addr6 =
1173                                         (struct sockaddr_in6 *)&server->dstaddr;
1174
1175                 if (!ipv6_addr_equal(&addr6->sin6_addr,
1176                                      &srv_addr6->sin6_addr))
1177                         return false;
1178                 if (addr6->sin6_scope_id != srv_addr6->sin6_scope_id)
1179                         return false;
1180                 break;
1181         }
1182         default:
1183                 WARN_ON(1);
1184                 return false; /* don't expect to be here */
1185         }
1186
1187         if (!cifs_match_ipaddr(srcaddr, (struct sockaddr *)&server->srcaddr))
1188                 return false;
1189
1190         return true;
1191 }
1192
1193 static bool
1194 match_security(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1195 {
1196         /*
1197          * The select_sectype function should either return the ctx->sectype
1198          * that was specified, or "Unspecified" if that sectype was not
1199          * compatible with the given NEGOTIATE request.
1200          */
1201         if (server->ops->select_sectype(server, ctx->sectype)
1202              == Unspecified)
1203                 return false;
1204
1205         /*
1206          * Now check if signing mode is acceptable. No need to check
1207          * global_secflags at this point since if MUST_SIGN is set then
1208          * the server->sign had better be too.
1209          */
1210         if (ctx->sign && !server->sign)
1211                 return false;
1212
1213         return true;
1214 }
1215
1216 static int match_server(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1217 {
1218         struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
1219
1220         if (ctx->nosharesock) {
1221                 server->nosharesock = true;
1222                 return 0;
1223         }
1224
1225         /* this server does not share socket */
1226         if (server->nosharesock)
1227                 return 0;
1228
1229         /* If multidialect negotiation see if existing sessions match one */
1230         if (strcmp(ctx->vals->version_string, SMB3ANY_VERSION_STRING) == 0) {
1231                 if (server->vals->protocol_id < SMB30_PROT_ID)
1232                         return 0;
1233         } else if (strcmp(ctx->vals->version_string,
1234                    SMBDEFAULT_VERSION_STRING) == 0) {
1235                 if (server->vals->protocol_id < SMB21_PROT_ID)
1236                         return 0;
1237         } else if ((server->vals != ctx->vals) || (server->ops != ctx->ops))
1238                 return 0;
1239
1240         if (!net_eq(cifs_net_ns(server), current->nsproxy->net_ns))
1241                 return 0;
1242
1243         if (strcasecmp(server->hostname, ctx->server_hostname))
1244                 return 0;
1245
1246         if (!match_address(server, addr,
1247                            (struct sockaddr *)&ctx->srcaddr))
1248                 return 0;
1249
1250         if (!match_port(server, addr))
1251                 return 0;
1252
1253         if (!match_security(server, ctx))
1254                 return 0;
1255
1256         if (server->echo_interval != ctx->echo_interval * HZ)
1257                 return 0;
1258
1259         if (server->rdma != ctx->rdma)
1260                 return 0;
1261
1262         if (server->ignore_signature != ctx->ignore_signature)
1263                 return 0;
1264
1265         if (server->min_offload != ctx->min_offload)
1266                 return 0;
1267
1268         return 1;
1269 }
1270
1271 struct TCP_Server_Info *
1272 cifs_find_tcp_session(struct smb3_fs_context *ctx)
1273 {
1274         struct TCP_Server_Info *server;
1275
1276         spin_lock(&cifs_tcp_ses_lock);
1277         list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
1278 #ifdef CONFIG_CIFS_DFS_UPCALL
1279                 /*
1280                  * DFS failover implementation in cifs_reconnect() requires unique tcp sessions for
1281                  * DFS connections to do failover properly, so avoid sharing them with regular
1282                  * shares or even links that may connect to same server but having completely
1283                  * different failover targets.
1284                  */
1285                 if (server->is_dfs_conn)
1286                         continue;
1287 #endif
1288                 /*
1289                  * Skip ses channels since they're only handled in lower layers
1290                  * (e.g. cifs_send_recv).
1291                  */
1292                 if (server->is_channel || !match_server(server, ctx))
1293                         continue;
1294
1295                 ++server->srv_count;
1296                 spin_unlock(&cifs_tcp_ses_lock);
1297                 cifs_dbg(FYI, "Existing tcp session with server found\n");
1298                 return server;
1299         }
1300         spin_unlock(&cifs_tcp_ses_lock);
1301         return NULL;
1302 }
1303
1304 void
1305 cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
1306 {
1307         struct task_struct *task;
1308
1309         spin_lock(&cifs_tcp_ses_lock);
1310         if (--server->srv_count > 0) {
1311                 spin_unlock(&cifs_tcp_ses_lock);
1312                 return;
1313         }
1314
1315         /* srv_count can never go negative */
1316         WARN_ON(server->srv_count < 0);
1317
1318         put_net(cifs_net_ns(server));
1319
1320         list_del_init(&server->tcp_ses_list);
1321         spin_unlock(&cifs_tcp_ses_lock);
1322
1323         cancel_delayed_work_sync(&server->echo);
1324         cancel_delayed_work_sync(&server->resolve);
1325
1326         if (from_reconnect)
1327                 /*
1328                  * Avoid deadlock here: reconnect work calls
1329                  * cifs_put_tcp_session() at its end. Need to be sure
1330                  * that reconnect work does nothing with server pointer after
1331                  * that step.
1332                  */
1333                 cancel_delayed_work(&server->reconnect);
1334         else
1335                 cancel_delayed_work_sync(&server->reconnect);
1336
1337         spin_lock(&GlobalMid_Lock);
1338         server->tcpStatus = CifsExiting;
1339         spin_unlock(&GlobalMid_Lock);
1340
1341         cifs_crypto_secmech_release(server);
1342         cifs_fscache_release_client_cookie(server);
1343
1344         kfree(server->session_key.response);
1345         server->session_key.response = NULL;
1346         server->session_key.len = 0;
1347         kfree(server->hostname);
1348
1349         task = xchg(&server->tsk, NULL);
1350         if (task)
1351                 send_sig(SIGKILL, task, 1);
1352 }
1353
1354 struct TCP_Server_Info *
1355 cifs_get_tcp_session(struct smb3_fs_context *ctx)
1356 {
1357         struct TCP_Server_Info *tcp_ses = NULL;
1358         int rc;
1359
1360         cifs_dbg(FYI, "UNC: %s\n", ctx->UNC);
1361
1362         /* see if we already have a matching tcp_ses */
1363         tcp_ses = cifs_find_tcp_session(ctx);
1364         if (tcp_ses)
1365                 return tcp_ses;
1366
1367         tcp_ses = kzalloc(sizeof(struct TCP_Server_Info), GFP_KERNEL);
1368         if (!tcp_ses) {
1369                 rc = -ENOMEM;
1370                 goto out_err;
1371         }
1372
1373         tcp_ses->hostname = kstrdup(ctx->server_hostname, GFP_KERNEL);
1374         if (!tcp_ses->hostname) {
1375                 rc = -ENOMEM;
1376                 goto out_err;
1377         }
1378
1379         tcp_ses->ops = ctx->ops;
1380         tcp_ses->vals = ctx->vals;
1381         cifs_set_net_ns(tcp_ses, get_net(current->nsproxy->net_ns));
1382
1383         tcp_ses->conn_id = atomic_inc_return(&tcpSesNextId);
1384         tcp_ses->noblockcnt = ctx->rootfs;
1385         tcp_ses->noblocksnd = ctx->noblocksnd || ctx->rootfs;
1386         tcp_ses->noautotune = ctx->noautotune;
1387         tcp_ses->tcp_nodelay = ctx->sockopt_tcp_nodelay;
1388         tcp_ses->rdma = ctx->rdma;
1389         tcp_ses->in_flight = 0;
1390         tcp_ses->max_in_flight = 0;
1391         tcp_ses->credits = 1;
1392         init_waitqueue_head(&tcp_ses->response_q);
1393         init_waitqueue_head(&tcp_ses->request_q);
1394         INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
1395         mutex_init(&tcp_ses->srv_mutex);
1396         memcpy(tcp_ses->workstation_RFC1001_name,
1397                 ctx->source_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1398         memcpy(tcp_ses->server_RFC1001_name,
1399                 ctx->target_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1400         tcp_ses->session_estab = false;
1401         tcp_ses->sequence_number = 0;
1402         tcp_ses->reconnect_instance = 1;
1403         tcp_ses->lstrp = jiffies;
1404         tcp_ses->compress_algorithm = cpu_to_le16(ctx->compression);
1405         spin_lock_init(&tcp_ses->req_lock);
1406         INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
1407         INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
1408         INIT_DELAYED_WORK(&tcp_ses->echo, cifs_echo_request);
1409         INIT_DELAYED_WORK(&tcp_ses->resolve, cifs_resolve_server);
1410         INIT_DELAYED_WORK(&tcp_ses->reconnect, smb2_reconnect_server);
1411         mutex_init(&tcp_ses->reconnect_mutex);
1412         memcpy(&tcp_ses->srcaddr, &ctx->srcaddr,
1413                sizeof(tcp_ses->srcaddr));
1414         memcpy(&tcp_ses->dstaddr, &ctx->dstaddr,
1415                 sizeof(tcp_ses->dstaddr));
1416         if (ctx->use_client_guid)
1417                 memcpy(tcp_ses->client_guid, ctx->client_guid,
1418                        SMB2_CLIENT_GUID_SIZE);
1419         else
1420                 generate_random_uuid(tcp_ses->client_guid);
1421         /*
1422          * at this point we are the only ones with the pointer
1423          * to the struct since the kernel thread not created yet
1424          * no need to spinlock this init of tcpStatus or srv_count
1425          */
1426         tcp_ses->tcpStatus = CifsNew;
1427         ++tcp_ses->srv_count;
1428
1429         if (ctx->echo_interval >= SMB_ECHO_INTERVAL_MIN &&
1430                 ctx->echo_interval <= SMB_ECHO_INTERVAL_MAX)
1431                 tcp_ses->echo_interval = ctx->echo_interval * HZ;
1432         else
1433                 tcp_ses->echo_interval = SMB_ECHO_INTERVAL_DEFAULT * HZ;
1434         if (tcp_ses->rdma) {
1435 #ifndef CONFIG_CIFS_SMB_DIRECT
1436                 cifs_dbg(VFS, "CONFIG_CIFS_SMB_DIRECT is not enabled\n");
1437                 rc = -ENOENT;
1438                 goto out_err_crypto_release;
1439 #endif
1440                 tcp_ses->smbd_conn = smbd_get_connection(
1441                         tcp_ses, (struct sockaddr *)&ctx->dstaddr);
1442                 if (tcp_ses->smbd_conn) {
1443                         cifs_dbg(VFS, "RDMA transport established\n");
1444                         rc = 0;
1445                         goto smbd_connected;
1446                 } else {
1447                         rc = -ENOENT;
1448                         goto out_err_crypto_release;
1449                 }
1450         }
1451         rc = ip_connect(tcp_ses);
1452         if (rc < 0) {
1453                 cifs_dbg(VFS, "Error connecting to socket. Aborting operation.\n");
1454                 goto out_err_crypto_release;
1455         }
1456 smbd_connected:
1457         /*
1458          * since we're in a cifs function already, we know that
1459          * this will succeed. No need for try_module_get().
1460          */
1461         __module_get(THIS_MODULE);
1462         tcp_ses->tsk = kthread_run(cifs_demultiplex_thread,
1463                                   tcp_ses, "cifsd");
1464         if (IS_ERR(tcp_ses->tsk)) {
1465                 rc = PTR_ERR(tcp_ses->tsk);
1466                 cifs_dbg(VFS, "error %d create cifsd thread\n", rc);
1467                 module_put(THIS_MODULE);
1468                 goto out_err_crypto_release;
1469         }
1470         tcp_ses->min_offload = ctx->min_offload;
1471         /*
1472          * at this point we are the only ones with the pointer
1473          * to the struct since the kernel thread not created yet
1474          * no need to spinlock this update of tcpStatus
1475          */
1476         tcp_ses->tcpStatus = CifsNeedNegotiate;
1477
1478         if ((ctx->max_credits < 20) || (ctx->max_credits > 60000))
1479                 tcp_ses->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
1480         else
1481                 tcp_ses->max_credits = ctx->max_credits;
1482
1483         tcp_ses->nr_targets = 1;
1484         tcp_ses->ignore_signature = ctx->ignore_signature;
1485         /* thread spawned, put it on the list */
1486         spin_lock(&cifs_tcp_ses_lock);
1487         list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
1488         spin_unlock(&cifs_tcp_ses_lock);
1489
1490         cifs_fscache_get_client_cookie(tcp_ses);
1491
1492         /* queue echo request delayed work */
1493         queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
1494
1495         /* queue dns resolution delayed work */
1496         cifs_dbg(FYI, "%s: next dns resolution scheduled for %d seconds in the future\n",
1497                  __func__, SMB_DNS_RESOLVE_INTERVAL_DEFAULT);
1498
1499         queue_delayed_work(cifsiod_wq, &tcp_ses->resolve, (SMB_DNS_RESOLVE_INTERVAL_DEFAULT * HZ));
1500
1501         return tcp_ses;
1502
1503 out_err_crypto_release:
1504         cifs_crypto_secmech_release(tcp_ses);
1505
1506         put_net(cifs_net_ns(tcp_ses));
1507
1508 out_err:
1509         if (tcp_ses) {
1510                 kfree(tcp_ses->hostname);
1511                 if (tcp_ses->ssocket)
1512                         sock_release(tcp_ses->ssocket);
1513                 kfree(tcp_ses);
1514         }
1515         return ERR_PTR(rc);
1516 }
1517
1518 static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1519 {
1520         if (ctx->sectype != Unspecified &&
1521             ctx->sectype != ses->sectype)
1522                 return 0;
1523
1524         /*
1525          * If an existing session is limited to less channels than
1526          * requested, it should not be reused
1527          */
1528         if (ses->chan_max < ctx->max_channels)
1529                 return 0;
1530
1531         switch (ses->sectype) {
1532         case Kerberos:
1533                 if (!uid_eq(ctx->cred_uid, ses->cred_uid))
1534                         return 0;
1535                 break;
1536         default:
1537                 /* NULL username means anonymous session */
1538                 if (ses->user_name == NULL) {
1539                         if (!ctx->nullauth)
1540                                 return 0;
1541                         break;
1542                 }
1543
1544                 /* anything else takes username/password */
1545                 if (strncmp(ses->user_name,
1546                             ctx->username ? ctx->username : "",
1547                             CIFS_MAX_USERNAME_LEN))
1548                         return 0;
1549                 if ((ctx->username && strlen(ctx->username) != 0) &&
1550                     ses->password != NULL &&
1551                     strncmp(ses->password,
1552                             ctx->password ? ctx->password : "",
1553                             CIFS_MAX_PASSWORD_LEN))
1554                         return 0;
1555         }
1556         return 1;
1557 }
1558
1559 /**
1560  * cifs_setup_ipc - helper to setup the IPC tcon for the session
1561  * @ses: smb session to issue the request on
1562  * @ctx: the superblock configuration context to use for building the
1563  *       new tree connection for the IPC (interprocess communication RPC)
1564  *
1565  * A new IPC connection is made and stored in the session
1566  * tcon_ipc. The IPC tcon has the same lifetime as the session.
1567  */
1568 static int
1569 cifs_setup_ipc(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1570 {
1571         int rc = 0, xid;
1572         struct cifs_tcon *tcon;
1573         char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0};
1574         bool seal = false;
1575         struct TCP_Server_Info *server = ses->server;
1576
1577         /*
1578          * If the mount request that resulted in the creation of the
1579          * session requires encryption, force IPC to be encrypted too.
1580          */
1581         if (ctx->seal) {
1582                 if (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)
1583                         seal = true;
1584                 else {
1585                         cifs_server_dbg(VFS,
1586                                  "IPC: server doesn't support encryption\n");
1587                         return -EOPNOTSUPP;
1588                 }
1589         }
1590
1591         tcon = tconInfoAlloc();
1592         if (tcon == NULL)
1593                 return -ENOMEM;
1594
1595         scnprintf(unc, sizeof(unc), "\\\\%s\\IPC$", server->hostname);
1596
1597         xid = get_xid();
1598         tcon->ses = ses;
1599         tcon->ipc = true;
1600         tcon->seal = seal;
1601         rc = server->ops->tree_connect(xid, ses, unc, tcon, ctx->local_nls);
1602         free_xid(xid);
1603
1604         if (rc) {
1605                 cifs_server_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
1606                 tconInfoFree(tcon);
1607                 goto out;
1608         }
1609
1610         cifs_dbg(FYI, "IPC tcon rc = %d ipc tid = %d\n", rc, tcon->tid);
1611
1612         ses->tcon_ipc = tcon;
1613 out:
1614         return rc;
1615 }
1616
1617 /**
1618  * cifs_free_ipc - helper to release the session IPC tcon
1619  * @ses: smb session to unmount the IPC from
1620  *
1621  * Needs to be called everytime a session is destroyed.
1622  *
1623  * On session close, the IPC is closed and the server must release all tcons of the session.
1624  * No need to send a tree disconnect here.
1625  *
1626  * Besides, it will make the server to not close durable and resilient files on session close, as
1627  * specified in MS-SMB2 3.3.5.6 Receiving an SMB2 LOGOFF Request.
1628  */
1629 static int
1630 cifs_free_ipc(struct cifs_ses *ses)
1631 {
1632         struct cifs_tcon *tcon = ses->tcon_ipc;
1633
1634         if (tcon == NULL)
1635                 return 0;
1636
1637         tconInfoFree(tcon);
1638         ses->tcon_ipc = NULL;
1639         return 0;
1640 }
1641
1642 static struct cifs_ses *
1643 cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1644 {
1645         struct cifs_ses *ses;
1646
1647         spin_lock(&cifs_tcp_ses_lock);
1648         list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
1649                 if (ses->status == CifsExiting)
1650                         continue;
1651                 if (!match_session(ses, ctx))
1652                         continue;
1653                 ++ses->ses_count;
1654                 spin_unlock(&cifs_tcp_ses_lock);
1655                 return ses;
1656         }
1657         spin_unlock(&cifs_tcp_ses_lock);
1658         return NULL;
1659 }
1660
1661 void cifs_put_smb_ses(struct cifs_ses *ses)
1662 {
1663         unsigned int rc, xid;
1664         struct TCP_Server_Info *server = ses->server;
1665         cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
1666
1667         spin_lock(&cifs_tcp_ses_lock);
1668         if (ses->status == CifsExiting) {
1669                 spin_unlock(&cifs_tcp_ses_lock);
1670                 return;
1671         }
1672
1673         cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
1674         cifs_dbg(FYI, "%s: ses ipc: %s\n", __func__, ses->tcon_ipc ? ses->tcon_ipc->treeName : "NONE");
1675
1676         if (--ses->ses_count > 0) {
1677                 spin_unlock(&cifs_tcp_ses_lock);
1678                 return;
1679         }
1680         spin_unlock(&cifs_tcp_ses_lock);
1681
1682         /* ses_count can never go negative */
1683         WARN_ON(ses->ses_count < 0);
1684
1685         spin_lock(&GlobalMid_Lock);
1686         if (ses->status == CifsGood)
1687                 ses->status = CifsExiting;
1688         spin_unlock(&GlobalMid_Lock);
1689
1690         cifs_free_ipc(ses);
1691
1692         if (ses->status == CifsExiting && server->ops->logoff) {
1693                 xid = get_xid();
1694                 rc = server->ops->logoff(xid, ses);
1695                 if (rc)
1696                         cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
1697                                 __func__, rc);
1698                 _free_xid(xid);
1699         }
1700
1701         spin_lock(&cifs_tcp_ses_lock);
1702         list_del_init(&ses->smb_ses_list);
1703         spin_unlock(&cifs_tcp_ses_lock);
1704
1705         /* close any extra channels */
1706         if (ses->chan_count > 1) {
1707                 int i;
1708
1709                 for (i = 1; i < ses->chan_count; i++)
1710                         cifs_put_tcp_session(ses->chans[i].server, 0);
1711         }
1712
1713         sesInfoFree(ses);
1714         cifs_put_tcp_session(server, 0);
1715 }
1716
1717 #ifdef CONFIG_KEYS
1718
1719 /* strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1 */
1720 #define CIFSCREDS_DESC_SIZE (7 + CIFS_MAX_DOMAINNAME_LEN + 1)
1721
1722 /* Populate username and pw fields from keyring if possible */
1723 static int
1724 cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
1725 {
1726         int rc = 0;
1727         int is_domain = 0;
1728         const char *delim, *payload;
1729         char *desc;
1730         ssize_t len;
1731         struct key *key;
1732         struct TCP_Server_Info *server = ses->server;
1733         struct sockaddr_in *sa;
1734         struct sockaddr_in6 *sa6;
1735         const struct user_key_payload *upayload;
1736
1737         desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
1738         if (!desc)
1739                 return -ENOMEM;
1740
1741         /* try to find an address key first */
1742         switch (server->dstaddr.ss_family) {
1743         case AF_INET:
1744                 sa = (struct sockaddr_in *)&server->dstaddr;
1745                 sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
1746                 break;
1747         case AF_INET6:
1748                 sa6 = (struct sockaddr_in6 *)&server->dstaddr;
1749                 sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
1750                 break;
1751         default:
1752                 cifs_dbg(FYI, "Bad ss_family (%hu)\n",
1753                          server->dstaddr.ss_family);
1754                 rc = -EINVAL;
1755                 goto out_err;
1756         }
1757
1758         cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
1759         key = request_key(&key_type_logon, desc, "");
1760         if (IS_ERR(key)) {
1761                 if (!ses->domainName) {
1762                         cifs_dbg(FYI, "domainName is NULL\n");
1763                         rc = PTR_ERR(key);
1764                         goto out_err;
1765                 }
1766
1767                 /* didn't work, try to find a domain key */
1768                 sprintf(desc, "cifs:d:%s", ses->domainName);
1769                 cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
1770                 key = request_key(&key_type_logon, desc, "");
1771                 if (IS_ERR(key)) {
1772                         rc = PTR_ERR(key);
1773                         goto out_err;
1774                 }
1775                 is_domain = 1;
1776         }
1777
1778         down_read(&key->sem);
1779         upayload = user_key_payload_locked(key);
1780         if (IS_ERR_OR_NULL(upayload)) {
1781                 rc = upayload ? PTR_ERR(upayload) : -EINVAL;
1782                 goto out_key_put;
1783         }
1784
1785         /* find first : in payload */
1786         payload = upayload->data;
1787         delim = strnchr(payload, upayload->datalen, ':');
1788         cifs_dbg(FYI, "payload=%s\n", payload);
1789         if (!delim) {
1790                 cifs_dbg(FYI, "Unable to find ':' in payload (datalen=%d)\n",
1791                          upayload->datalen);
1792                 rc = -EINVAL;
1793                 goto out_key_put;
1794         }
1795
1796         len = delim - payload;
1797         if (len > CIFS_MAX_USERNAME_LEN || len <= 0) {
1798                 cifs_dbg(FYI, "Bad value from username search (len=%zd)\n",
1799                          len);
1800                 rc = -EINVAL;
1801                 goto out_key_put;
1802         }
1803
1804         ctx->username = kstrndup(payload, len, GFP_KERNEL);
1805         if (!ctx->username) {
1806                 cifs_dbg(FYI, "Unable to allocate %zd bytes for username\n",
1807                          len);
1808                 rc = -ENOMEM;
1809                 goto out_key_put;
1810         }
1811         cifs_dbg(FYI, "%s: username=%s\n", __func__, ctx->username);
1812
1813         len = key->datalen - (len + 1);
1814         if (len > CIFS_MAX_PASSWORD_LEN || len <= 0) {
1815                 cifs_dbg(FYI, "Bad len for password search (len=%zd)\n", len);
1816                 rc = -EINVAL;
1817                 kfree(ctx->username);
1818                 ctx->username = NULL;
1819                 goto out_key_put;
1820         }
1821
1822         ++delim;
1823         ctx->password = kstrndup(delim, len, GFP_KERNEL);
1824         if (!ctx->password) {
1825                 cifs_dbg(FYI, "Unable to allocate %zd bytes for password\n",
1826                          len);
1827                 rc = -ENOMEM;
1828                 kfree(ctx->username);
1829                 ctx->username = NULL;
1830                 goto out_key_put;
1831         }
1832
1833         /*
1834          * If we have a domain key then we must set the domainName in the
1835          * for the request.
1836          */
1837         if (is_domain && ses->domainName) {
1838                 ctx->domainname = kstrdup(ses->domainName, GFP_KERNEL);
1839                 if (!ctx->domainname) {
1840                         cifs_dbg(FYI, "Unable to allocate %zd bytes for domain\n",
1841                                  len);
1842                         rc = -ENOMEM;
1843                         kfree(ctx->username);
1844                         ctx->username = NULL;
1845                         kfree_sensitive(ctx->password);
1846                         ctx->password = NULL;
1847                         goto out_key_put;
1848                 }
1849         }
1850
1851 out_key_put:
1852         up_read(&key->sem);
1853         key_put(key);
1854 out_err:
1855         kfree(desc);
1856         cifs_dbg(FYI, "%s: returning %d\n", __func__, rc);
1857         return rc;
1858 }
1859 #else /* ! CONFIG_KEYS */
1860 static inline int
1861 cifs_set_cifscreds(struct smb3_fs_context *ctx __attribute__((unused)),
1862                    struct cifs_ses *ses __attribute__((unused)))
1863 {
1864         return -ENOSYS;
1865 }
1866 #endif /* CONFIG_KEYS */
1867
1868 /**
1869  * cifs_get_smb_ses - get a session matching @ctx data from @server
1870  * @server: server to setup the session to
1871  * @ctx: superblock configuration context to use to setup the session
1872  *
1873  * This function assumes it is being called from cifs_mount() where we
1874  * already got a server reference (server refcount +1). See
1875  * cifs_get_tcon() for refcount explanations.
1876  */
1877 struct cifs_ses *
1878 cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1879 {
1880         int rc = -ENOMEM;
1881         unsigned int xid;
1882         struct cifs_ses *ses;
1883         struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
1884         struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
1885
1886         xid = get_xid();
1887
1888         ses = cifs_find_smb_ses(server, ctx);
1889         if (ses) {
1890                 cifs_dbg(FYI, "Existing smb sess found (status=%d)\n",
1891                          ses->status);
1892
1893                 mutex_lock(&ses->session_mutex);
1894                 rc = cifs_negotiate_protocol(xid, ses);
1895                 if (rc) {
1896                         mutex_unlock(&ses->session_mutex);
1897                         /* problem -- put our ses reference */
1898                         cifs_put_smb_ses(ses);
1899                         free_xid(xid);
1900                         return ERR_PTR(rc);
1901                 }
1902                 if (ses->need_reconnect) {
1903                         cifs_dbg(FYI, "Session needs reconnect\n");
1904                         rc = cifs_setup_session(xid, ses,
1905                                                 ctx->local_nls);
1906                         if (rc) {
1907                                 mutex_unlock(&ses->session_mutex);
1908                                 /* problem -- put our reference */
1909                                 cifs_put_smb_ses(ses);
1910                                 free_xid(xid);
1911                                 return ERR_PTR(rc);
1912                         }
1913                 }
1914                 mutex_unlock(&ses->session_mutex);
1915
1916                 /* existing SMB ses has a server reference already */
1917                 cifs_put_tcp_session(server, 0);
1918                 free_xid(xid);
1919                 return ses;
1920         }
1921
1922         cifs_dbg(FYI, "Existing smb sess not found\n");
1923         ses = sesInfoAlloc();
1924         if (ses == NULL)
1925                 goto get_ses_fail;
1926
1927         /* new SMB session uses our server ref */
1928         ses->server = server;
1929         if (server->dstaddr.ss_family == AF_INET6)
1930                 sprintf(ses->ip_addr, "%pI6", &addr6->sin6_addr);
1931         else
1932                 sprintf(ses->ip_addr, "%pI4", &addr->sin_addr);
1933
1934         if (ctx->username) {
1935                 ses->user_name = kstrdup(ctx->username, GFP_KERNEL);
1936                 if (!ses->user_name)
1937                         goto get_ses_fail;
1938         }
1939
1940         /* ctx->password freed at unmount */
1941         if (ctx->password) {
1942                 ses->password = kstrdup(ctx->password, GFP_KERNEL);
1943                 if (!ses->password)
1944                         goto get_ses_fail;
1945         }
1946         if (ctx->domainname) {
1947                 ses->domainName = kstrdup(ctx->domainname, GFP_KERNEL);
1948                 if (!ses->domainName)
1949                         goto get_ses_fail;
1950         }
1951         if (ctx->workstation_name) {
1952                 ses->workstation_name = kstrdup(ctx->workstation_name,
1953                                                 GFP_KERNEL);
1954                 if (!ses->workstation_name)
1955                         goto get_ses_fail;
1956         }
1957         if (ctx->domainauto)
1958                 ses->domainAuto = ctx->domainauto;
1959         ses->cred_uid = ctx->cred_uid;
1960         ses->linux_uid = ctx->linux_uid;
1961
1962         ses->sectype = ctx->sectype;
1963         ses->sign = ctx->sign;
1964         mutex_lock(&ses->session_mutex);
1965
1966         /* add server as first channel */
1967         ses->chans[0].server = server;
1968         ses->chan_count = 1;
1969         ses->chan_max = ctx->multichannel ? ctx->max_channels:1;
1970
1971         rc = cifs_negotiate_protocol(xid, ses);
1972         if (!rc)
1973                 rc = cifs_setup_session(xid, ses, ctx->local_nls);
1974
1975         /* each channel uses a different signing key */
1976         memcpy(ses->chans[0].signkey, ses->smb3signingkey,
1977                sizeof(ses->smb3signingkey));
1978
1979         mutex_unlock(&ses->session_mutex);
1980         if (rc)
1981                 goto get_ses_fail;
1982
1983         /* success, put it on the list and add it as first channel */
1984         spin_lock(&cifs_tcp_ses_lock);
1985         list_add(&ses->smb_ses_list, &server->smb_ses_list);
1986         spin_unlock(&cifs_tcp_ses_lock);
1987
1988         free_xid(xid);
1989
1990         cifs_setup_ipc(ses, ctx);
1991
1992         return ses;
1993
1994 get_ses_fail:
1995         sesInfoFree(ses);
1996         free_xid(xid);
1997         return ERR_PTR(rc);
1998 }
1999
2000 static int match_tcon(struct cifs_tcon *tcon, struct smb3_fs_context *ctx)
2001 {
2002         if (tcon->tidStatus == CifsExiting)
2003                 return 0;
2004         if (strncmp(tcon->treeName, ctx->UNC, MAX_TREE_SIZE))
2005                 return 0;
2006         if (tcon->seal != ctx->seal)
2007                 return 0;
2008         if (tcon->snapshot_time != ctx->snapshot_time)
2009                 return 0;
2010         if (tcon->handle_timeout != ctx->handle_timeout)
2011                 return 0;
2012         if (tcon->no_lease != ctx->no_lease)
2013                 return 0;
2014         if (tcon->nodelete != ctx->nodelete)
2015                 return 0;
2016         return 1;
2017 }
2018
2019 static struct cifs_tcon *
2020 cifs_find_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2021 {
2022         struct list_head *tmp;
2023         struct cifs_tcon *tcon;
2024
2025         spin_lock(&cifs_tcp_ses_lock);
2026         list_for_each(tmp, &ses->tcon_list) {
2027                 tcon = list_entry(tmp, struct cifs_tcon, tcon_list);
2028
2029                 if (!match_tcon(tcon, ctx))
2030                         continue;
2031                 ++tcon->tc_count;
2032                 spin_unlock(&cifs_tcp_ses_lock);
2033                 return tcon;
2034         }
2035         spin_unlock(&cifs_tcp_ses_lock);
2036         return NULL;
2037 }
2038
2039 void
2040 cifs_put_tcon(struct cifs_tcon *tcon)
2041 {
2042         unsigned int xid;
2043         struct cifs_ses *ses;
2044
2045         /*
2046          * IPC tcon share the lifetime of their session and are
2047          * destroyed in the session put function
2048          */
2049         if (tcon == NULL || tcon->ipc)
2050                 return;
2051
2052         ses = tcon->ses;
2053         cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
2054         spin_lock(&cifs_tcp_ses_lock);
2055         if (--tcon->tc_count > 0) {
2056                 spin_unlock(&cifs_tcp_ses_lock);
2057                 return;
2058         }
2059
2060         /* tc_count can never go negative */
2061         WARN_ON(tcon->tc_count < 0);
2062
2063         if (tcon->use_witness) {
2064                 int rc;
2065
2066                 rc = cifs_swn_unregister(tcon);
2067                 if (rc < 0) {
2068                         cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
2069                                         __func__, rc);
2070                 }
2071         }
2072
2073         list_del_init(&tcon->tcon_list);
2074         spin_unlock(&cifs_tcp_ses_lock);
2075
2076         xid = get_xid();
2077         if (ses->server->ops->tree_disconnect)
2078                 ses->server->ops->tree_disconnect(xid, tcon);
2079         _free_xid(xid);
2080
2081         cifs_fscache_release_super_cookie(tcon);
2082         tconInfoFree(tcon);
2083         cifs_put_smb_ses(ses);
2084 }
2085
2086 /**
2087  * cifs_get_tcon - get a tcon matching @ctx data from @ses
2088  * @ses: smb session to issue the request on
2089  * @ctx: the superblock configuration context to use for building the
2090  *
2091  * - tcon refcount is the number of mount points using the tcon.
2092  * - ses refcount is the number of tcon using the session.
2093  *
2094  * 1. This function assumes it is being called from cifs_mount() where
2095  *    we already got a session reference (ses refcount +1).
2096  *
2097  * 2. Since we're in the context of adding a mount point, the end
2098  *    result should be either:
2099  *
2100  * a) a new tcon already allocated with refcount=1 (1 mount point) and
2101  *    its session refcount incremented (1 new tcon). This +1 was
2102  *    already done in (1).
2103  *
2104  * b) an existing tcon with refcount+1 (add a mount point to it) and
2105  *    identical ses refcount (no new tcon). Because of (1) we need to
2106  *    decrement the ses refcount.
2107  */
2108 static struct cifs_tcon *
2109 cifs_get_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2110 {
2111         int rc, xid;
2112         struct cifs_tcon *tcon;
2113
2114         tcon = cifs_find_tcon(ses, ctx);
2115         if (tcon) {
2116                 /*
2117                  * tcon has refcount already incremented but we need to
2118                  * decrement extra ses reference gotten by caller (case b)
2119                  */
2120                 cifs_dbg(FYI, "Found match on UNC path\n");
2121                 cifs_put_smb_ses(ses);
2122                 return tcon;
2123         }
2124
2125         if (!ses->server->ops->tree_connect) {
2126                 rc = -ENOSYS;
2127                 goto out_fail;
2128         }
2129
2130         tcon = tconInfoAlloc();
2131         if (tcon == NULL) {
2132                 rc = -ENOMEM;
2133                 goto out_fail;
2134         }
2135
2136         if (ctx->snapshot_time) {
2137                 if (ses->server->vals->protocol_id == 0) {
2138                         cifs_dbg(VFS,
2139                              "Use SMB2 or later for snapshot mount option\n");
2140                         rc = -EOPNOTSUPP;
2141                         goto out_fail;
2142                 } else
2143                         tcon->snapshot_time = ctx->snapshot_time;
2144         }
2145
2146         if (ctx->handle_timeout) {
2147                 if (ses->server->vals->protocol_id == 0) {
2148                         cifs_dbg(VFS,
2149                              "Use SMB2.1 or later for handle timeout option\n");
2150                         rc = -EOPNOTSUPP;
2151                         goto out_fail;
2152                 } else
2153                         tcon->handle_timeout = ctx->handle_timeout;
2154         }
2155
2156         tcon->ses = ses;
2157         if (ctx->password) {
2158                 tcon->password = kstrdup(ctx->password, GFP_KERNEL);
2159                 if (!tcon->password) {
2160                         rc = -ENOMEM;
2161                         goto out_fail;
2162                 }
2163         }
2164
2165         if (ctx->seal) {
2166                 if (ses->server->vals->protocol_id == 0) {
2167                         cifs_dbg(VFS,
2168                                  "SMB3 or later required for encryption\n");
2169                         rc = -EOPNOTSUPP;
2170                         goto out_fail;
2171                 } else if (tcon->ses->server->capabilities &
2172                                         SMB2_GLOBAL_CAP_ENCRYPTION)
2173                         tcon->seal = true;
2174                 else {
2175                         cifs_dbg(VFS, "Encryption is not supported on share\n");
2176                         rc = -EOPNOTSUPP;
2177                         goto out_fail;
2178                 }
2179         }
2180
2181         if (ctx->linux_ext) {
2182                 if (ses->server->posix_ext_supported) {
2183                         tcon->posix_extensions = true;
2184                         pr_warn_once("SMB3.11 POSIX Extensions are experimental\n");
2185                 } else {
2186                         cifs_dbg(VFS, "Server does not support mounting with posix SMB3.11 extensions\n");
2187                         rc = -EOPNOTSUPP;
2188                         goto out_fail;
2189                 }
2190         }
2191
2192         /*
2193          * BB Do we need to wrap session_mutex around this TCon call and Unix
2194          * SetFS as we do on SessSetup and reconnect?
2195          */
2196         xid = get_xid();
2197         rc = ses->server->ops->tree_connect(xid, ses, ctx->UNC, tcon,
2198                                             ctx->local_nls);
2199         free_xid(xid);
2200         cifs_dbg(FYI, "Tcon rc = %d\n", rc);
2201         if (rc)
2202                 goto out_fail;
2203
2204         tcon->use_persistent = false;
2205         /* check if SMB2 or later, CIFS does not support persistent handles */
2206         if (ctx->persistent) {
2207                 if (ses->server->vals->protocol_id == 0) {
2208                         cifs_dbg(VFS,
2209                              "SMB3 or later required for persistent handles\n");
2210                         rc = -EOPNOTSUPP;
2211                         goto out_fail;
2212                 } else if (ses->server->capabilities &
2213                            SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2214                         tcon->use_persistent = true;
2215                 else /* persistent handles requested but not supported */ {
2216                         cifs_dbg(VFS,
2217                                 "Persistent handles not supported on share\n");
2218                         rc = -EOPNOTSUPP;
2219                         goto out_fail;
2220                 }
2221         } else if ((tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
2222              && (ses->server->capabilities & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2223              && (ctx->nopersistent == false)) {
2224                 cifs_dbg(FYI, "enabling persistent handles\n");
2225                 tcon->use_persistent = true;
2226         } else if (ctx->resilient) {
2227                 if (ses->server->vals->protocol_id == 0) {
2228                         cifs_dbg(VFS,
2229                              "SMB2.1 or later required for resilient handles\n");
2230                         rc = -EOPNOTSUPP;
2231                         goto out_fail;
2232                 }
2233                 tcon->use_resilient = true;
2234         }
2235
2236         tcon->use_witness = false;
2237         if (IS_ENABLED(CONFIG_CIFS_SWN_UPCALL) && ctx->witness) {
2238                 if (ses->server->vals->protocol_id >= SMB30_PROT_ID) {
2239                         if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER) {
2240                                 /*
2241                                  * Set witness in use flag in first place
2242                                  * to retry registration in the echo task
2243                                  */
2244                                 tcon->use_witness = true;
2245                                 /* And try to register immediately */
2246                                 rc = cifs_swn_register(tcon);
2247                                 if (rc < 0) {
2248                                         cifs_dbg(VFS, "Failed to register for witness notifications: %d\n", rc);
2249                                         goto out_fail;
2250                                 }
2251                         } else {
2252                                 /* TODO: try to extend for non-cluster uses (eg multichannel) */
2253                                 cifs_dbg(VFS, "witness requested on mount but no CLUSTER capability on share\n");
2254                                 rc = -EOPNOTSUPP;
2255                                 goto out_fail;
2256                         }
2257                 } else {
2258                         cifs_dbg(VFS, "SMB3 or later required for witness option\n");
2259                         rc = -EOPNOTSUPP;
2260                         goto out_fail;
2261                 }
2262         }
2263
2264         /* If the user really knows what they are doing they can override */
2265         if (tcon->share_flags & SMB2_SHAREFLAG_NO_CACHING) {
2266                 if (ctx->cache_ro)
2267                         cifs_dbg(VFS, "cache=ro requested on mount but NO_CACHING flag set on share\n");
2268                 else if (ctx->cache_rw)
2269                         cifs_dbg(VFS, "cache=singleclient requested on mount but NO_CACHING flag set on share\n");
2270         }
2271
2272         if (ctx->no_lease) {
2273                 if (ses->server->vals->protocol_id == 0) {
2274                         cifs_dbg(VFS,
2275                                 "SMB2 or later required for nolease option\n");
2276                         rc = -EOPNOTSUPP;
2277                         goto out_fail;
2278                 } else
2279                         tcon->no_lease = ctx->no_lease;
2280         }
2281
2282         /*
2283          * We can have only one retry value for a connection to a share so for
2284          * resources mounted more than once to the same server share the last
2285          * value passed in for the retry flag is used.
2286          */
2287         tcon->retry = ctx->retry;
2288         tcon->nocase = ctx->nocase;
2289         if (ses->server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING)
2290                 tcon->nohandlecache = ctx->nohandlecache;
2291         else
2292                 tcon->nohandlecache = true;
2293         tcon->nodelete = ctx->nodelete;
2294         tcon->local_lease = ctx->local_lease;
2295         INIT_LIST_HEAD(&tcon->pending_opens);
2296
2297         spin_lock(&cifs_tcp_ses_lock);
2298         list_add(&tcon->tcon_list, &ses->tcon_list);
2299         spin_unlock(&cifs_tcp_ses_lock);
2300
2301         cifs_fscache_get_super_cookie(tcon);
2302
2303         return tcon;
2304
2305 out_fail:
2306         tconInfoFree(tcon);
2307         return ERR_PTR(rc);
2308 }
2309
2310 void
2311 cifs_put_tlink(struct tcon_link *tlink)
2312 {
2313         if (!tlink || IS_ERR(tlink))
2314                 return;
2315
2316         if (!atomic_dec_and_test(&tlink->tl_count) ||
2317             test_bit(TCON_LINK_IN_TREE, &tlink->tl_flags)) {
2318                 tlink->tl_time = jiffies;
2319                 return;
2320         }
2321
2322         if (!IS_ERR(tlink_tcon(tlink)))
2323                 cifs_put_tcon(tlink_tcon(tlink));
2324         kfree(tlink);
2325         return;
2326 }
2327
2328 static int
2329 compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
2330 {
2331         struct cifs_sb_info *old = CIFS_SB(sb);
2332         struct cifs_sb_info *new = mnt_data->cifs_sb;
2333         unsigned int oldflags = old->mnt_cifs_flags & CIFS_MOUNT_MASK;
2334         unsigned int newflags = new->mnt_cifs_flags & CIFS_MOUNT_MASK;
2335
2336         if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
2337                 return 0;
2338
2339         if (old->mnt_cifs_serverino_autodisabled)
2340                 newflags &= ~CIFS_MOUNT_SERVER_INUM;
2341
2342         if (oldflags != newflags)
2343                 return 0;
2344
2345         /*
2346          * We want to share sb only if we don't specify an r/wsize or
2347          * specified r/wsize is greater than or equal to existing one.
2348          */
2349         if (new->ctx->wsize && new->ctx->wsize < old->ctx->wsize)
2350                 return 0;
2351
2352         if (new->ctx->rsize && new->ctx->rsize < old->ctx->rsize)
2353                 return 0;
2354
2355         if (!uid_eq(old->ctx->linux_uid, new->ctx->linux_uid) ||
2356             !gid_eq(old->ctx->linux_gid, new->ctx->linux_gid))
2357                 return 0;
2358
2359         if (old->ctx->file_mode != new->ctx->file_mode ||
2360             old->ctx->dir_mode != new->ctx->dir_mode)
2361                 return 0;
2362
2363         if (strcmp(old->local_nls->charset, new->local_nls->charset))
2364                 return 0;
2365
2366         if (old->ctx->acregmax != new->ctx->acregmax)
2367                 return 0;
2368         if (old->ctx->acdirmax != new->ctx->acdirmax)
2369                 return 0;
2370
2371         return 1;
2372 }
2373
2374 static int
2375 match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
2376 {
2377         struct cifs_sb_info *old = CIFS_SB(sb);
2378         struct cifs_sb_info *new = mnt_data->cifs_sb;
2379         bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2380                 old->prepath;
2381         bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2382                 new->prepath;
2383
2384         if (old_set && new_set && !strcmp(new->prepath, old->prepath))
2385                 return 1;
2386         else if (!old_set && !new_set)
2387                 return 1;
2388
2389         return 0;
2390 }
2391
2392 int
2393 cifs_match_super(struct super_block *sb, void *data)
2394 {
2395         struct cifs_mnt_data *mnt_data = (struct cifs_mnt_data *)data;
2396         struct smb3_fs_context *ctx;
2397         struct cifs_sb_info *cifs_sb;
2398         struct TCP_Server_Info *tcp_srv;
2399         struct cifs_ses *ses;
2400         struct cifs_tcon *tcon;
2401         struct tcon_link *tlink;
2402         int rc = 0;
2403
2404         spin_lock(&cifs_tcp_ses_lock);
2405         cifs_sb = CIFS_SB(sb);
2406         tlink = cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
2407         if (tlink == NULL) {
2408                 /* can not match superblock if tlink were ever null */
2409                 spin_unlock(&cifs_tcp_ses_lock);
2410                 return 0;
2411         }
2412         tcon = tlink_tcon(tlink);
2413         ses = tcon->ses;
2414         tcp_srv = ses->server;
2415
2416         ctx = mnt_data->ctx;
2417
2418         if (!match_server(tcp_srv, ctx) ||
2419             !match_session(ses, ctx) ||
2420             !match_tcon(tcon, ctx) ||
2421             !match_prepath(sb, mnt_data)) {
2422                 rc = 0;
2423                 goto out;
2424         }
2425
2426         rc = compare_mount_options(sb, mnt_data);
2427 out:
2428         spin_unlock(&cifs_tcp_ses_lock);
2429         cifs_put_tlink(tlink);
2430         return rc;
2431 }
2432
2433 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2434 static struct lock_class_key cifs_key[2];
2435 static struct lock_class_key cifs_slock_key[2];
2436
2437 static inline void
2438 cifs_reclassify_socket4(struct socket *sock)
2439 {
2440         struct sock *sk = sock->sk;
2441         BUG_ON(!sock_allow_reclassification(sk));
2442         sock_lock_init_class_and_name(sk, "slock-AF_INET-CIFS",
2443                 &cifs_slock_key[0], "sk_lock-AF_INET-CIFS", &cifs_key[0]);
2444 }
2445
2446 static inline void
2447 cifs_reclassify_socket6(struct socket *sock)
2448 {
2449         struct sock *sk = sock->sk;
2450         BUG_ON(!sock_allow_reclassification(sk));
2451         sock_lock_init_class_and_name(sk, "slock-AF_INET6-CIFS",
2452                 &cifs_slock_key[1], "sk_lock-AF_INET6-CIFS", &cifs_key[1]);
2453 }
2454 #else
2455 static inline void
2456 cifs_reclassify_socket4(struct socket *sock)
2457 {
2458 }
2459
2460 static inline void
2461 cifs_reclassify_socket6(struct socket *sock)
2462 {
2463 }
2464 #endif
2465
2466 /* See RFC1001 section 14 on representation of Netbios names */
2467 static void rfc1002mangle(char *target, char *source, unsigned int length)
2468 {
2469         unsigned int i, j;
2470
2471         for (i = 0, j = 0; i < (length); i++) {
2472                 /* mask a nibble at a time and encode */
2473                 target[j] = 'A' + (0x0F & (source[i] >> 4));
2474                 target[j+1] = 'A' + (0x0F & source[i]);
2475                 j += 2;
2476         }
2477
2478 }
2479
2480 static int
2481 bind_socket(struct TCP_Server_Info *server)
2482 {
2483         int rc = 0;
2484         if (server->srcaddr.ss_family != AF_UNSPEC) {
2485                 /* Bind to the specified local IP address */
2486                 struct socket *socket = server->ssocket;
2487                 rc = socket->ops->bind(socket,
2488                                        (struct sockaddr *) &server->srcaddr,
2489                                        sizeof(server->srcaddr));
2490                 if (rc < 0) {
2491                         struct sockaddr_in *saddr4;
2492                         struct sockaddr_in6 *saddr6;
2493                         saddr4 = (struct sockaddr_in *)&server->srcaddr;
2494                         saddr6 = (struct sockaddr_in6 *)&server->srcaddr;
2495                         if (saddr6->sin6_family == AF_INET6)
2496                                 cifs_server_dbg(VFS, "Failed to bind to: %pI6c, error: %d\n",
2497                                          &saddr6->sin6_addr, rc);
2498                         else
2499                                 cifs_server_dbg(VFS, "Failed to bind to: %pI4, error: %d\n",
2500                                          &saddr4->sin_addr.s_addr, rc);
2501                 }
2502         }
2503         return rc;
2504 }
2505
2506 static int
2507 ip_rfc1001_connect(struct TCP_Server_Info *server)
2508 {
2509         int rc = 0;
2510         /*
2511          * some servers require RFC1001 sessinit before sending
2512          * negprot - BB check reconnection in case where second
2513          * sessinit is sent but no second negprot
2514          */
2515         struct rfc1002_session_packet *ses_init_buf;
2516         struct smb_hdr *smb_buf;
2517         ses_init_buf = kzalloc(sizeof(struct rfc1002_session_packet),
2518                                GFP_KERNEL);
2519         if (ses_init_buf) {
2520                 ses_init_buf->trailer.session_req.called_len = 32;
2521
2522                 if (server->server_RFC1001_name[0] != 0)
2523                         rfc1002mangle(ses_init_buf->trailer.
2524                                       session_req.called_name,
2525                                       server->server_RFC1001_name,
2526                                       RFC1001_NAME_LEN_WITH_NULL);
2527                 else
2528                         rfc1002mangle(ses_init_buf->trailer.
2529                                       session_req.called_name,
2530                                       DEFAULT_CIFS_CALLED_NAME,
2531                                       RFC1001_NAME_LEN_WITH_NULL);
2532
2533                 ses_init_buf->trailer.session_req.calling_len = 32;
2534
2535                 /*
2536                  * calling name ends in null (byte 16) from old smb
2537                  * convention.
2538                  */
2539                 if (server->workstation_RFC1001_name[0] != 0)
2540                         rfc1002mangle(ses_init_buf->trailer.
2541                                       session_req.calling_name,
2542                                       server->workstation_RFC1001_name,
2543                                       RFC1001_NAME_LEN_WITH_NULL);
2544                 else
2545                         rfc1002mangle(ses_init_buf->trailer.
2546                                       session_req.calling_name,
2547                                       "LINUX_CIFS_CLNT",
2548                                       RFC1001_NAME_LEN_WITH_NULL);
2549
2550                 ses_init_buf->trailer.session_req.scope1 = 0;
2551                 ses_init_buf->trailer.session_req.scope2 = 0;
2552                 smb_buf = (struct smb_hdr *)ses_init_buf;
2553
2554                 /* sizeof RFC1002_SESSION_REQUEST with no scope */
2555                 smb_buf->smb_buf_length = cpu_to_be32(0x81000044);
2556                 rc = smb_send(server, smb_buf, 0x44);
2557                 kfree(ses_init_buf);
2558                 /*
2559                  * RFC1001 layer in at least one server
2560                  * requires very short break before negprot
2561                  * presumably because not expecting negprot
2562                  * to follow so fast.  This is a simple
2563                  * solution that works without
2564                  * complicating the code and causes no
2565                  * significant slowing down on mount
2566                  * for everyone else
2567                  */
2568                 usleep_range(1000, 2000);
2569         }
2570         /*
2571          * else the negprot may still work without this
2572          * even though malloc failed
2573          */
2574
2575         return rc;
2576 }
2577
2578 static int
2579 generic_ip_connect(struct TCP_Server_Info *server)
2580 {
2581         int rc = 0;
2582         __be16 sport;
2583         int slen, sfamily;
2584         struct socket *socket = server->ssocket;
2585         struct sockaddr *saddr;
2586
2587         saddr = (struct sockaddr *) &server->dstaddr;
2588
2589         if (server->dstaddr.ss_family == AF_INET6) {
2590                 struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)&server->dstaddr;
2591
2592                 sport = ipv6->sin6_port;
2593                 slen = sizeof(struct sockaddr_in6);
2594                 sfamily = AF_INET6;
2595                 cifs_dbg(FYI, "%s: connecting to [%pI6]:%d\n", __func__, &ipv6->sin6_addr,
2596                                 ntohs(sport));
2597         } else {
2598                 struct sockaddr_in *ipv4 = (struct sockaddr_in *)&server->dstaddr;
2599
2600                 sport = ipv4->sin_port;
2601                 slen = sizeof(struct sockaddr_in);
2602                 sfamily = AF_INET;
2603                 cifs_dbg(FYI, "%s: connecting to %pI4:%d\n", __func__, &ipv4->sin_addr,
2604                                 ntohs(sport));
2605         }
2606
2607         if (socket == NULL) {
2608                 rc = __sock_create(cifs_net_ns(server), sfamily, SOCK_STREAM,
2609                                    IPPROTO_TCP, &socket, 1);
2610                 if (rc < 0) {
2611                         cifs_server_dbg(VFS, "Error %d creating socket\n", rc);
2612                         server->ssocket = NULL;
2613                         return rc;
2614                 }
2615
2616                 /* BB other socket options to set KEEPALIVE, NODELAY? */
2617                 cifs_dbg(FYI, "Socket created\n");
2618                 server->ssocket = socket;
2619                 socket->sk->sk_allocation = GFP_NOFS;
2620                 if (sfamily == AF_INET6)
2621                         cifs_reclassify_socket6(socket);
2622                 else
2623                         cifs_reclassify_socket4(socket);
2624         }
2625
2626         rc = bind_socket(server);
2627         if (rc < 0)
2628                 return rc;
2629
2630         /*
2631          * Eventually check for other socket options to change from
2632          * the default. sock_setsockopt not used because it expects
2633          * user space buffer
2634          */
2635         socket->sk->sk_rcvtimeo = 7 * HZ;
2636         socket->sk->sk_sndtimeo = 5 * HZ;
2637
2638         /* make the bufsizes depend on wsize/rsize and max requests */
2639         if (server->noautotune) {
2640                 if (socket->sk->sk_sndbuf < (200 * 1024))
2641                         socket->sk->sk_sndbuf = 200 * 1024;
2642                 if (socket->sk->sk_rcvbuf < (140 * 1024))
2643                         socket->sk->sk_rcvbuf = 140 * 1024;
2644         }
2645
2646         if (server->tcp_nodelay)
2647                 tcp_sock_set_nodelay(socket->sk);
2648
2649         cifs_dbg(FYI, "sndbuf %d rcvbuf %d rcvtimeo 0x%lx\n",
2650                  socket->sk->sk_sndbuf,
2651                  socket->sk->sk_rcvbuf, socket->sk->sk_rcvtimeo);
2652
2653         rc = socket->ops->connect(socket, saddr, slen,
2654                                   server->noblockcnt ? O_NONBLOCK : 0);
2655         /*
2656          * When mounting SMB root file systems, we do not want to block in
2657          * connect. Otherwise bail out and then let cifs_reconnect() perform
2658          * reconnect failover - if possible.
2659          */
2660         if (server->noblockcnt && rc == -EINPROGRESS)
2661                 rc = 0;
2662         if (rc < 0) {
2663                 cifs_dbg(FYI, "Error %d connecting to server\n", rc);
2664                 trace_smb3_connect_err(server->hostname, server->conn_id, &server->dstaddr, rc);
2665                 sock_release(socket);
2666                 server->ssocket = NULL;
2667                 return rc;
2668         }
2669         trace_smb3_connect_done(server->hostname, server->conn_id, &server->dstaddr);
2670         if (sport == htons(RFC1001_PORT))
2671                 rc = ip_rfc1001_connect(server);
2672
2673         return rc;
2674 }
2675
2676 static int
2677 ip_connect(struct TCP_Server_Info *server)
2678 {
2679         __be16 *sport;
2680         struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
2681         struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
2682
2683         if (server->dstaddr.ss_family == AF_INET6)
2684                 sport = &addr6->sin6_port;
2685         else
2686                 sport = &addr->sin_port;
2687
2688         if (*sport == 0) {
2689                 int rc;
2690
2691                 /* try with 445 port at first */
2692                 *sport = htons(CIFS_PORT);
2693
2694                 rc = generic_ip_connect(server);
2695                 if (rc >= 0)
2696                         return rc;
2697
2698                 /* if it failed, try with 139 port */
2699                 *sport = htons(RFC1001_PORT);
2700         }
2701
2702         return generic_ip_connect(server);
2703 }
2704
2705 void reset_cifs_unix_caps(unsigned int xid, struct cifs_tcon *tcon,
2706                           struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
2707 {
2708         /*
2709          * If we are reconnecting then should we check to see if
2710          * any requested capabilities changed locally e.g. via
2711          * remount but we can not do much about it here
2712          * if they have (even if we could detect it by the following)
2713          * Perhaps we could add a backpointer to array of sb from tcon
2714          * or if we change to make all sb to same share the same
2715          * sb as NFS - then we only have one backpointer to sb.
2716          * What if we wanted to mount the server share twice once with
2717          * and once without posixacls or posix paths?
2718          */
2719         __u64 saved_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
2720
2721         if (ctx && ctx->no_linux_ext) {
2722                 tcon->fsUnixInfo.Capability = 0;
2723                 tcon->unix_ext = 0; /* Unix Extensions disabled */
2724                 cifs_dbg(FYI, "Linux protocol extensions disabled\n");
2725                 return;
2726         } else if (ctx)
2727                 tcon->unix_ext = 1; /* Unix Extensions supported */
2728
2729         if (!tcon->unix_ext) {
2730                 cifs_dbg(FYI, "Unix extensions disabled so not set on reconnect\n");
2731                 return;
2732         }
2733
2734         if (!CIFSSMBQFSUnixInfo(xid, tcon)) {
2735                 __u64 cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
2736                 cifs_dbg(FYI, "unix caps which server supports %lld\n", cap);
2737                 /*
2738                  * check for reconnect case in which we do not
2739                  * want to change the mount behavior if we can avoid it
2740                  */
2741                 if (ctx == NULL) {
2742                         /*
2743                          * turn off POSIX ACL and PATHNAMES if not set
2744                          * originally at mount time
2745                          */
2746                         if ((saved_cap & CIFS_UNIX_POSIX_ACL_CAP) == 0)
2747                                 cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
2748                         if ((saved_cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
2749                                 if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
2750                                         cifs_dbg(VFS, "POSIXPATH support change\n");
2751                                 cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
2752                         } else if ((cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
2753                                 cifs_dbg(VFS, "possible reconnect error\n");
2754                                 cifs_dbg(VFS, "server disabled POSIX path support\n");
2755                         }
2756                 }
2757
2758                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
2759                         cifs_dbg(VFS, "per-share encryption not supported yet\n");
2760
2761                 cap &= CIFS_UNIX_CAP_MASK;
2762                 if (ctx && ctx->no_psx_acl)
2763                         cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
2764                 else if (CIFS_UNIX_POSIX_ACL_CAP & cap) {
2765                         cifs_dbg(FYI, "negotiated posix acl support\n");
2766                         if (cifs_sb)
2767                                 cifs_sb->mnt_cifs_flags |=
2768                                         CIFS_MOUNT_POSIXACL;
2769                 }
2770
2771                 if (ctx && ctx->posix_paths == 0)
2772                         cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
2773                 else if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) {
2774                         cifs_dbg(FYI, "negotiate posix pathnames\n");
2775                         if (cifs_sb)
2776                                 cifs_sb->mnt_cifs_flags |=
2777                                         CIFS_MOUNT_POSIX_PATHS;
2778                 }
2779
2780                 cifs_dbg(FYI, "Negotiate caps 0x%x\n", (int)cap);
2781 #ifdef CONFIG_CIFS_DEBUG2
2782                 if (cap & CIFS_UNIX_FCNTL_CAP)
2783                         cifs_dbg(FYI, "FCNTL cap\n");
2784                 if (cap & CIFS_UNIX_EXTATTR_CAP)
2785                         cifs_dbg(FYI, "EXTATTR cap\n");
2786                 if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
2787                         cifs_dbg(FYI, "POSIX path cap\n");
2788                 if (cap & CIFS_UNIX_XATTR_CAP)
2789                         cifs_dbg(FYI, "XATTR cap\n");
2790                 if (cap & CIFS_UNIX_POSIX_ACL_CAP)
2791                         cifs_dbg(FYI, "POSIX ACL cap\n");
2792                 if (cap & CIFS_UNIX_LARGE_READ_CAP)
2793                         cifs_dbg(FYI, "very large read cap\n");
2794                 if (cap & CIFS_UNIX_LARGE_WRITE_CAP)
2795                         cifs_dbg(FYI, "very large write cap\n");
2796                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_CAP)
2797                         cifs_dbg(FYI, "transport encryption cap\n");
2798                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
2799                         cifs_dbg(FYI, "mandatory transport encryption cap\n");
2800 #endif /* CIFS_DEBUG2 */
2801                 if (CIFSSMBSetFSUnixInfo(xid, tcon, cap)) {
2802                         if (ctx == NULL)
2803                                 cifs_dbg(FYI, "resetting capabilities failed\n");
2804                         else
2805                                 cifs_dbg(VFS, "Negotiating Unix capabilities with the server failed. Consider mounting with the Unix Extensions disabled if problems are found by specifying the nounix mount option.\n");
2806
2807                 }
2808         }
2809 }
2810
2811 int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb)
2812 {
2813         struct smb3_fs_context *ctx = cifs_sb->ctx;
2814
2815         INIT_DELAYED_WORK(&cifs_sb->prune_tlinks, cifs_prune_tlinks);
2816
2817         spin_lock_init(&cifs_sb->tlink_tree_lock);
2818         cifs_sb->tlink_tree = RB_ROOT;
2819
2820         cifs_dbg(FYI, "file mode: %04ho  dir mode: %04ho\n",
2821                  ctx->file_mode, ctx->dir_mode);
2822
2823         /* this is needed for ASCII cp to Unicode converts */
2824         if (ctx->iocharset == NULL) {
2825                 /* load_nls_default cannot return null */
2826                 cifs_sb->local_nls = load_nls_default();
2827         } else {
2828                 cifs_sb->local_nls = load_nls(ctx->iocharset);
2829                 if (cifs_sb->local_nls == NULL) {
2830                         cifs_dbg(VFS, "CIFS mount error: iocharset %s not found\n",
2831                                  ctx->iocharset);
2832                         return -ELIBACC;
2833                 }
2834         }
2835         ctx->local_nls = cifs_sb->local_nls;
2836
2837         smb3_update_mnt_flags(cifs_sb);
2838
2839         if (ctx->direct_io)
2840                 cifs_dbg(FYI, "mounting share using direct i/o\n");
2841         if (ctx->cache_ro) {
2842                 cifs_dbg(VFS, "mounting share with read only caching. Ensure that the share will not be modified while in use.\n");
2843                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RO_CACHE;
2844         } else if (ctx->cache_rw) {
2845                 cifs_dbg(VFS, "mounting share in single client RW caching mode. Ensure that no other systems will be accessing the share.\n");
2846                 cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_RO_CACHE |
2847                                             CIFS_MOUNT_RW_CACHE);
2848         }
2849
2850         if ((ctx->cifs_acl) && (ctx->dynperm))
2851                 cifs_dbg(VFS, "mount option dynperm ignored if cifsacl mount option supported\n");
2852
2853         if (ctx->prepath) {
2854                 cifs_sb->prepath = kstrdup(ctx->prepath, GFP_KERNEL);
2855                 if (cifs_sb->prepath == NULL)
2856                         return -ENOMEM;
2857                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
2858         }
2859
2860         return 0;
2861 }
2862
2863 /* Release all succeed connections */
2864 static inline void mount_put_conns(struct cifs_sb_info *cifs_sb,
2865                                    unsigned int xid,
2866                                    struct TCP_Server_Info *server,
2867                                    struct cifs_ses *ses, struct cifs_tcon *tcon)
2868 {
2869         int rc = 0;
2870
2871         if (tcon)
2872                 cifs_put_tcon(tcon);
2873         else if (ses)
2874                 cifs_put_smb_ses(ses);
2875         else if (server)
2876                 cifs_put_tcp_session(server, 0);
2877         cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
2878         free_xid(xid);
2879 }
2880
2881 /* Get connections for tcp, ses and tcon */
2882 static int mount_get_conns(struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
2883                            unsigned int *xid,
2884                            struct TCP_Server_Info **nserver,
2885                            struct cifs_ses **nses, struct cifs_tcon **ntcon)
2886 {
2887         int rc = 0;
2888         struct TCP_Server_Info *server;
2889         struct cifs_ses *ses;
2890         struct cifs_tcon *tcon;
2891
2892         *nserver = NULL;
2893         *nses = NULL;
2894         *ntcon = NULL;
2895
2896         *xid = get_xid();
2897
2898         /* get a reference to a tcp session */
2899         server = cifs_get_tcp_session(ctx);
2900         if (IS_ERR(server)) {
2901                 rc = PTR_ERR(server);
2902                 return rc;
2903         }
2904
2905         *nserver = server;
2906
2907         /* get a reference to a SMB session */
2908         ses = cifs_get_smb_ses(server, ctx);
2909         if (IS_ERR(ses)) {
2910                 rc = PTR_ERR(ses);
2911                 return rc;
2912         }
2913
2914         *nses = ses;
2915
2916         if ((ctx->persistent == true) && (!(ses->server->capabilities &
2917                                             SMB2_GLOBAL_CAP_PERSISTENT_HANDLES))) {
2918                 cifs_server_dbg(VFS, "persistent handles not supported by server\n");
2919                 return -EOPNOTSUPP;
2920         }
2921
2922         /* search for existing tcon to this server share */
2923         tcon = cifs_get_tcon(ses, ctx);
2924         if (IS_ERR(tcon)) {
2925                 rc = PTR_ERR(tcon);
2926                 return rc;
2927         }
2928
2929         *ntcon = tcon;
2930
2931         /* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
2932         if (tcon->posix_extensions)
2933                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_POSIX_PATHS;
2934
2935         /* tell server which Unix caps we support */
2936         if (cap_unix(tcon->ses)) {
2937                 /*
2938                  * reset of caps checks mount to see if unix extensions disabled
2939                  * for just this mount.
2940                  */
2941                 reset_cifs_unix_caps(*xid, tcon, cifs_sb, ctx);
2942                 if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
2943                     (le64_to_cpu(tcon->fsUnixInfo.Capability) &
2944                      CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP))
2945                         return -EACCES;
2946         } else
2947                 tcon->unix_ext = 0; /* server does not support them */
2948
2949         /* do not care if a following call succeed - informational */
2950         if (!tcon->pipe && server->ops->qfs_tcon) {
2951                 server->ops->qfs_tcon(*xid, tcon, cifs_sb);
2952                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RO_CACHE) {
2953                         if (tcon->fsDevInfo.DeviceCharacteristics &
2954                             cpu_to_le32(FILE_READ_ONLY_DEVICE))
2955                                 cifs_dbg(VFS, "mounted to read only share\n");
2956                         else if ((cifs_sb->mnt_cifs_flags &
2957                                   CIFS_MOUNT_RW_CACHE) == 0)
2958                                 cifs_dbg(VFS, "read only mount of RW share\n");
2959                         /* no need to log a RW mount of a typical RW share */
2960                 }
2961         }
2962
2963         /*
2964          * Clamp the rsize/wsize mount arguments if they are too big for the server
2965          * and set the rsize/wsize to the negotiated values if not passed in by
2966          * the user on mount
2967          */
2968         if ((cifs_sb->ctx->wsize == 0) ||
2969             (cifs_sb->ctx->wsize > server->ops->negotiate_wsize(tcon, ctx)))
2970                 cifs_sb->ctx->wsize = server->ops->negotiate_wsize(tcon, ctx);
2971         if ((cifs_sb->ctx->rsize == 0) ||
2972             (cifs_sb->ctx->rsize > server->ops->negotiate_rsize(tcon, ctx)))
2973                 cifs_sb->ctx->rsize = server->ops->negotiate_rsize(tcon, ctx);
2974
2975         return 0;
2976 }
2977
2978 static int mount_setup_tlink(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
2979                              struct cifs_tcon *tcon)
2980 {
2981         struct tcon_link *tlink;
2982
2983         /* hang the tcon off of the superblock */
2984         tlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
2985         if (tlink == NULL)
2986                 return -ENOMEM;
2987
2988         tlink->tl_uid = ses->linux_uid;
2989         tlink->tl_tcon = tcon;
2990         tlink->tl_time = jiffies;
2991         set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
2992         set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
2993
2994         cifs_sb->master_tlink = tlink;
2995         spin_lock(&cifs_sb->tlink_tree_lock);
2996         tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
2997         spin_unlock(&cifs_sb->tlink_tree_lock);
2998
2999         queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
3000                                 TLINK_IDLE_EXPIRE);
3001         return 0;
3002 }
3003
3004 #ifdef CONFIG_CIFS_DFS_UPCALL
3005 static int mount_get_dfs_conns(struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
3006                                unsigned int *xid, struct TCP_Server_Info **nserver,
3007                                struct cifs_ses **nses, struct cifs_tcon **ntcon)
3008 {
3009         int rc;
3010
3011         ctx->nosharesock = true;
3012         rc = mount_get_conns(ctx, cifs_sb, xid, nserver, nses, ntcon);
3013         if (*nserver) {
3014                 cifs_dbg(FYI, "%s: marking tcp session as a dfs connection\n", __func__);
3015                 spin_lock(&cifs_tcp_ses_lock);
3016                 (*nserver)->is_dfs_conn = true;
3017                 spin_unlock(&cifs_tcp_ses_lock);
3018         }
3019         return rc;
3020 }
3021
3022 /*
3023  * cifs_build_path_to_root returns full path to root when we do not have an
3024  * existing connection (tcon)
3025  */
3026 static char *
3027 build_unc_path_to_root(const struct smb3_fs_context *ctx,
3028                        const struct cifs_sb_info *cifs_sb, bool useppath)
3029 {
3030         char *full_path, *pos;
3031         unsigned int pplen = useppath && ctx->prepath ?
3032                 strlen(ctx->prepath) + 1 : 0;
3033         unsigned int unc_len = strnlen(ctx->UNC, MAX_TREE_SIZE + 1);
3034
3035         if (unc_len > MAX_TREE_SIZE)
3036                 return ERR_PTR(-EINVAL);
3037
3038         full_path = kmalloc(unc_len + pplen + 1, GFP_KERNEL);
3039         if (full_path == NULL)
3040                 return ERR_PTR(-ENOMEM);
3041
3042         memcpy(full_path, ctx->UNC, unc_len);
3043         pos = full_path + unc_len;
3044
3045         if (pplen) {
3046                 *pos = CIFS_DIR_SEP(cifs_sb);
3047                 memcpy(pos + 1, ctx->prepath, pplen);
3048                 pos += pplen;
3049         }
3050
3051         *pos = '\0'; /* add trailing null */
3052         convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb));
3053         cifs_dbg(FYI, "%s: full_path=%s\n", __func__, full_path);
3054         return full_path;
3055 }
3056
3057 /*
3058  * expand_dfs_referral - Perform a dfs referral query and update the cifs_sb
3059  *
3060  * If a referral is found, cifs_sb->ctx->mount_options will be (re-)allocated
3061  * to a string containing updated options for the submount.  Otherwise it
3062  * will be left untouched.
3063  *
3064  * Returns the rc from get_dfs_path to the caller, which can be used to
3065  * determine whether there were referrals.
3066  */
3067 static int
3068 expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
3069                     struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
3070                     char *ref_path)
3071 {
3072         int rc;
3073         struct dfs_info3_param referral = {0};
3074         char *full_path = NULL, *mdata = NULL;
3075
3076         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
3077                 return -EREMOTE;
3078
3079         full_path = build_unc_path_to_root(ctx, cifs_sb, true);
3080         if (IS_ERR(full_path))
3081                 return PTR_ERR(full_path);
3082
3083         rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
3084                             ref_path, &referral, NULL);
3085         if (!rc) {
3086                 char *fake_devname = NULL;
3087
3088                 mdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options,
3089                                                    full_path + 1, &referral,
3090                                                    &fake_devname);
3091                 free_dfs_info_param(&referral);
3092
3093                 if (IS_ERR(mdata)) {
3094                         rc = PTR_ERR(mdata);
3095                         mdata = NULL;
3096                 } else {
3097                         /*
3098                          * We can not clear out the whole structure since we
3099                          * no longer have an explicit function to parse
3100                          * a mount-string. Instead we need to clear out the
3101                          * individual fields that are no longer valid.
3102                          */
3103                         kfree(ctx->prepath);
3104                         ctx->prepath = NULL;
3105                         rc = cifs_setup_volume_info(ctx, mdata, fake_devname);
3106                 }
3107                 kfree(fake_devname);
3108                 kfree(cifs_sb->ctx->mount_options);
3109                 cifs_sb->ctx->mount_options = mdata;
3110         }
3111         kfree(full_path);
3112         return rc;
3113 }
3114
3115 static int get_next_dfs_tgt(struct dfs_cache_tgt_list *tgt_list,
3116                             struct dfs_cache_tgt_iterator **tgt_it)
3117 {
3118         if (!*tgt_it)
3119                 *tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
3120         else
3121                 *tgt_it = dfs_cache_get_next_tgt(tgt_list, *tgt_it);
3122         return !*tgt_it ? -EHOSTDOWN : 0;
3123 }
3124
3125 static int update_vol_info(const struct dfs_cache_tgt_iterator *tgt_it,
3126                            struct smb3_fs_context *fake_ctx, struct smb3_fs_context *ctx)
3127 {
3128         const char *tgt = dfs_cache_get_tgt_name(tgt_it);
3129         int len = strlen(tgt) + 2;
3130         char *new_unc;
3131
3132         new_unc = kmalloc(len, GFP_KERNEL);
3133         if (!new_unc)
3134                 return -ENOMEM;
3135         scnprintf(new_unc, len, "\\%s", tgt);
3136
3137         kfree(ctx->UNC);
3138         ctx->UNC = new_unc;
3139
3140         if (fake_ctx->prepath) {
3141                 kfree(ctx->prepath);
3142                 ctx->prepath = fake_ctx->prepath;
3143                 fake_ctx->prepath = NULL;
3144         }
3145         memcpy(&ctx->dstaddr, &fake_ctx->dstaddr, sizeof(ctx->dstaddr));
3146
3147         return 0;
3148 }
3149
3150 static int do_dfs_failover(const char *path, const char *full_path, struct cifs_sb_info *cifs_sb,
3151                            struct smb3_fs_context *ctx, struct cifs_ses *root_ses,
3152                            unsigned int *xid, struct TCP_Server_Info **server,
3153                            struct cifs_ses **ses, struct cifs_tcon **tcon)
3154 {
3155         int rc;
3156         char *npath = NULL;
3157         struct dfs_cache_tgt_list tgt_list = DFS_CACHE_TGT_LIST_INIT(tgt_list);
3158         struct dfs_cache_tgt_iterator *tgt_it = NULL;
3159         struct smb3_fs_context tmp_ctx = {NULL};
3160
3161         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
3162                 return -EOPNOTSUPP;
3163
3164         npath = dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));
3165         if (IS_ERR(npath))
3166                 return PTR_ERR(npath);
3167
3168         cifs_dbg(FYI, "%s: path=%s full_path=%s\n", __func__, npath, full_path);
3169
3170         rc = dfs_cache_noreq_find(npath, NULL, &tgt_list);
3171         if (rc)
3172                 goto out;
3173         /*
3174          * We use a 'tmp_ctx' here because we need pass it down to the mount_{get,put} functions to
3175          * test connection against new DFS targets.
3176          */
3177         rc = smb3_fs_context_dup(&tmp_ctx, ctx);
3178         if (rc)
3179                 goto out;
3180
3181         for (;;) {
3182                 struct dfs_info3_param ref = {0};
3183                 char *fake_devname = NULL, *mdata = NULL;
3184
3185                 /* Get next DFS target server - if any */
3186                 rc = get_next_dfs_tgt(&tgt_list, &tgt_it);
3187                 if (rc)
3188                         break;
3189
3190                 rc = dfs_cache_get_tgt_referral(npath, tgt_it, &ref);
3191                 if (rc)
3192                         break;
3193
3194                 cifs_dbg(FYI, "%s: old ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
3195                          tmp_ctx.prepath);
3196
3197                 mdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options, full_path + 1, &ref,
3198                                                    &fake_devname);
3199                 free_dfs_info_param(&ref);
3200
3201                 if (IS_ERR(mdata)) {
3202                         rc = PTR_ERR(mdata);
3203                         mdata = NULL;
3204                 } else
3205                         rc = cifs_setup_volume_info(&tmp_ctx, mdata, fake_devname);
3206
3207                 kfree(mdata);
3208                 kfree(fake_devname);
3209
3210                 if (rc)
3211                         break;
3212
3213                 cifs_dbg(FYI, "%s: new ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
3214                          tmp_ctx.prepath);
3215
3216                 mount_put_conns(cifs_sb, *xid, *server, *ses, *tcon);
3217                 rc = mount_get_dfs_conns(&tmp_ctx, cifs_sb, xid, server, ses, tcon);
3218                 if (!rc || (*server && *ses)) {
3219                         /*
3220                          * We were able to connect to new target server. Update current context with
3221                          * new target server.
3222                          */
3223                         rc = update_vol_info(tgt_it, &tmp_ctx, ctx);
3224                         break;
3225                 }
3226         }
3227         if (!rc) {
3228                 cifs_dbg(FYI, "%s: final ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
3229                          tmp_ctx.prepath);
3230                 /*
3231                  * Update DFS target hint in DFS referral cache with the target server we
3232                  * successfully reconnected to.
3233                  */
3234                 rc = dfs_cache_update_tgthint(*xid, root_ses ? root_ses : *ses, cifs_sb->local_nls,
3235                                               cifs_remap(cifs_sb), path, tgt_it);
3236         }
3237
3238 out:
3239         kfree(npath);
3240         smb3_cleanup_fs_context_contents(&tmp_ctx);
3241         dfs_cache_free_tgts(&tgt_list);
3242         return rc;
3243 }
3244 #endif
3245
3246 /* TODO: all callers to this are broken. We are not parsing mount_options here
3247  * we should pass a clone of the original context?
3248  */
3249 int
3250 cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname)
3251 {
3252         int rc;
3253
3254         if (devname) {
3255                 cifs_dbg(FYI, "%s: devname=%s\n", __func__, devname);
3256                 rc = smb3_parse_devname(devname, ctx);
3257                 if (rc) {
3258                         cifs_dbg(VFS, "%s: failed to parse %s: %d\n", __func__, devname, rc);
3259                         return rc;
3260                 }
3261         }
3262
3263         if (mntopts) {
3264                 char *ip;
3265
3266                 rc = smb3_parse_opt(mntopts, "ip", &ip);
3267                 if (rc) {
3268                         cifs_dbg(VFS, "%s: failed to parse ip options: %d\n", __func__, rc);
3269                         return rc;
3270                 }
3271
3272                 rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip));
3273                 kfree(ip);
3274                 if (!rc) {
3275                         cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);
3276                         return -EINVAL;
3277                 }
3278         }
3279
3280         if (ctx->nullauth) {
3281                 cifs_dbg(FYI, "Anonymous login\n");
3282                 kfree(ctx->username);
3283                 ctx->username = NULL;
3284         } else if (ctx->username) {
3285                 /* BB fixme parse for domain name here */
3286                 cifs_dbg(FYI, "Username: %s\n", ctx->username);
3287         } else {
3288                 cifs_dbg(VFS, "No username specified\n");
3289         /* In userspace mount helper we can get user name from alternate
3290            locations such as env variables and files on disk */
3291                 return -EINVAL;
3292         }
3293
3294         return 0;
3295 }
3296
3297 static int
3298 cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
3299                                         unsigned int xid,
3300                                         struct cifs_tcon *tcon,
3301                                         struct cifs_sb_info *cifs_sb,
3302                                         char *full_path,
3303                                         int added_treename)
3304 {
3305         int rc;
3306         char *s;
3307         char sep, tmp;
3308         int skip = added_treename ? 1 : 0;
3309
3310         sep = CIFS_DIR_SEP(cifs_sb);
3311         s = full_path;
3312
3313         rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, "");
3314         while (rc == 0) {
3315                 /* skip separators */
3316                 while (*s == sep)
3317                         s++;
3318                 if (!*s)
3319                         break;
3320                 /* next separator */
3321                 while (*s && *s != sep)
3322                         s++;
3323                 /*
3324                  * if the treename is added, we then have to skip the first
3325                  * part within the separators
3326                  */
3327                 if (skip) {
3328                         skip = 0;
3329                         continue;
3330                 }
3331                 /*
3332                  * temporarily null-terminate the path at the end of
3333                  * the current component
3334                  */
3335                 tmp = *s;
3336                 *s = 0;
3337                 rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3338                                                      full_path);
3339                 *s = tmp;
3340         }
3341         return rc;
3342 }
3343
3344 /*
3345  * Check if path is remote (e.g. a DFS share). Return -EREMOTE if it is,
3346  * otherwise 0.
3347  */
3348 static int is_path_remote(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx,
3349                           const unsigned int xid,
3350                           struct TCP_Server_Info *server,
3351                           struct cifs_tcon *tcon)
3352 {
3353         int rc;
3354         char *full_path;
3355
3356         if (!server->ops->is_path_accessible)
3357                 return -EOPNOTSUPP;
3358
3359         /*
3360          * cifs_build_path_to_root works only when we have a valid tcon
3361          */
3362         full_path = cifs_build_path_to_root(ctx, cifs_sb, tcon,
3363                                             tcon->Flags & SMB_SHARE_IS_IN_DFS);
3364         if (full_path == NULL)
3365                 return -ENOMEM;
3366
3367         cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
3368
3369         rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3370                                              full_path);
3371         if (rc != 0 && rc != -EREMOTE) {
3372                 kfree(full_path);
3373                 return rc;
3374         }
3375
3376         if (rc != -EREMOTE) {
3377                 rc = cifs_are_all_path_components_accessible(server, xid, tcon,
3378                         cifs_sb, full_path, tcon->Flags & SMB_SHARE_IS_IN_DFS);
3379                 if (rc != 0) {
3380                         cifs_server_dbg(VFS, "cannot query dirs between root and final path, enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
3381                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3382                         rc = 0;
3383                 }
3384         }
3385
3386         kfree(full_path);
3387         return rc;
3388 }
3389
3390 #ifdef CONFIG_CIFS_DFS_UPCALL
3391 static void set_root_ses(struct cifs_sb_info *cifs_sb, const uuid_t *mount_id, struct cifs_ses *ses,
3392                          struct cifs_ses **root_ses)
3393 {
3394         if (ses) {
3395                 spin_lock(&cifs_tcp_ses_lock);
3396                 ses->ses_count++;
3397                 spin_unlock(&cifs_tcp_ses_lock);
3398                 dfs_cache_add_refsrv_session(mount_id, ses);
3399         }
3400         *root_ses = ses;
3401 }
3402
3403 /* Set up next dfs prefix path in @dfs_path */
3404 static int next_dfs_prepath(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx,
3405                             const unsigned int xid, struct TCP_Server_Info *server,
3406                             struct cifs_tcon *tcon, char **dfs_path)
3407 {
3408         char *path, *npath;
3409         int added_treename = is_tcon_dfs(tcon);
3410         int rc;
3411
3412         path = cifs_build_path_to_root(ctx, cifs_sb, tcon, added_treename);
3413         if (!path)
3414                 return -ENOMEM;
3415
3416         rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
3417         if (rc == -EREMOTE) {
3418                 struct smb3_fs_context v = {NULL};
3419                 /* if @path contains a tree name, skip it in the prefix path */
3420                 if (added_treename) {
3421                         rc = smb3_parse_devname(path, &v);
3422                         if (rc)
3423                                 goto out;
3424                         npath = build_unc_path_to_root(&v, cifs_sb, true);
3425                         smb3_cleanup_fs_context_contents(&v);
3426                 } else {
3427                         v.UNC = ctx->UNC;
3428                         v.prepath = path + 1;
3429                         npath = build_unc_path_to_root(&v, cifs_sb, true);
3430                 }
3431
3432                 if (IS_ERR(npath)) {
3433                         rc = PTR_ERR(npath);
3434                         goto out;
3435                 }
3436
3437                 kfree(*dfs_path);
3438                 *dfs_path = npath;
3439                 rc = -EREMOTE;
3440         }
3441
3442 out:
3443         kfree(path);
3444         return rc;
3445 }
3446
3447 /* Check if resolved targets can handle any DFS referrals */
3448 static int is_referral_server(const char *ref_path, struct cifs_sb_info *cifs_sb,
3449                               struct cifs_tcon *tcon, bool *ref_server)
3450 {
3451         int rc;
3452         struct dfs_info3_param ref = {0};
3453
3454         cifs_dbg(FYI, "%s: ref_path=%s\n", __func__, ref_path);
3455
3456         if (is_tcon_dfs(tcon)) {
3457                 *ref_server = true;
3458         } else {
3459                 char *npath;
3460
3461                 npath = dfs_cache_canonical_path(ref_path, cifs_sb->local_nls, cifs_remap(cifs_sb));
3462                 if (IS_ERR(npath))
3463                         return PTR_ERR(npath);
3464
3465                 rc = dfs_cache_noreq_find(npath, &ref, NULL);
3466                 kfree(npath);
3467                 if (rc) {
3468                         cifs_dbg(VFS, "%s: dfs_cache_noreq_find: failed (rc=%d)\n", __func__, rc);
3469                         return rc;
3470                 }
3471                 cifs_dbg(FYI, "%s: ref.flags=0x%x\n", __func__, ref.flags);
3472                 /*
3473                  * Check if all targets are capable of handling DFS referrals as per
3474                  * MS-DFSC 2.2.4 RESP_GET_DFS_REFERRAL.
3475                  */
3476                 *ref_server = !!(ref.flags & DFSREF_REFERRAL_SERVER);
3477                 free_dfs_info_param(&ref);
3478         }
3479         return 0;
3480 }
3481
3482 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3483 {
3484         int rc = 0;
3485         unsigned int xid;
3486         struct TCP_Server_Info *server = NULL;
3487         struct cifs_ses *ses = NULL, *root_ses = NULL;
3488         struct cifs_tcon *tcon = NULL;
3489         int count = 0;
3490         uuid_t mount_id = {0};
3491         char *ref_path = NULL, *full_path = NULL;
3492         char *oldmnt = NULL;
3493         bool ref_server = false;
3494
3495         rc = mount_get_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
3496         /*
3497          * If called with 'nodfs' mount option, then skip DFS resolving.  Otherwise unconditionally
3498          * try to get an DFS referral (even cached) to determine whether it is an DFS mount.
3499          *
3500          * Skip prefix path to provide support for DFS referrals from w2k8 servers which don't seem
3501          * to respond with PATH_NOT_COVERED to requests that include the prefix.
3502          */
3503         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
3504             dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb), ctx->UNC + 1, NULL,
3505                            NULL)) {
3506                 if (rc)
3507                         goto error;
3508                 /* Check if it is fully accessible and then mount it */
3509                 rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
3510                 if (!rc)
3511                         goto out;
3512                 if (rc != -EREMOTE)
3513                         goto error;
3514         }
3515
3516         mount_put_conns(cifs_sb, xid, server, ses, tcon);
3517         /*
3518          * Ignore error check here because we may failover to other targets from cached a
3519          * referral.
3520          */
3521         (void)mount_get_dfs_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
3522
3523         /* Get path of DFS root */
3524         ref_path = build_unc_path_to_root(ctx, cifs_sb, false);
3525         if (IS_ERR(ref_path)) {
3526                 rc = PTR_ERR(ref_path);
3527                 ref_path = NULL;
3528                 goto error;
3529         }
3530
3531         uuid_gen(&mount_id);
3532         set_root_ses(cifs_sb, &mount_id, ses, &root_ses);
3533         do {
3534                 /* Save full path of last DFS path we used to resolve final target server */
3535                 kfree(full_path);
3536                 full_path = build_unc_path_to_root(ctx, cifs_sb, !!count);
3537                 if (IS_ERR(full_path)) {
3538                         rc = PTR_ERR(full_path);
3539                         full_path = NULL;
3540                         break;
3541                 }
3542                 /* Chase referral */
3543                 oldmnt = cifs_sb->ctx->mount_options;
3544                 rc = expand_dfs_referral(xid, root_ses, ctx, cifs_sb, ref_path + 1);
3545                 if (rc)
3546                         break;
3547                 /* Connect to new DFS target only if we were redirected */
3548                 if (oldmnt != cifs_sb->ctx->mount_options) {
3549                         mount_put_conns(cifs_sb, xid, server, ses, tcon);
3550                         rc = mount_get_dfs_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
3551                 }
3552                 if (rc && !server && !ses) {
3553                         /* Failed to connect. Try to connect to other targets in the referral. */
3554                         rc = do_dfs_failover(ref_path + 1, full_path, cifs_sb, ctx, root_ses, &xid,
3555                                              &server, &ses, &tcon);
3556                 }
3557                 if (rc == -EACCES || rc == -EOPNOTSUPP || !server || !ses)
3558                         break;
3559                 if (!tcon)
3560                         continue;
3561
3562                 /* Make sure that requests go through new root servers */
3563                 rc = is_referral_server(ref_path + 1, cifs_sb, tcon, &ref_server);
3564                 if (rc)
3565                         break;
3566                 if (ref_server)
3567                         set_root_ses(cifs_sb, &mount_id, ses, &root_ses);
3568
3569                 /* Get next dfs path and then continue chasing them if -EREMOTE */
3570                 rc = next_dfs_prepath(cifs_sb, ctx, xid, server, tcon, &ref_path);
3571                 /* Prevent recursion on broken link referrals */
3572                 if (rc == -EREMOTE && ++count > MAX_NESTED_LINKS)
3573                         rc = -ELOOP;
3574         } while (rc == -EREMOTE);
3575
3576         if (rc || !tcon || !ses)
3577                 goto error;
3578
3579         kfree(ref_path);
3580         /*
3581          * Store DFS full path in both superblock and tree connect structures.
3582          *
3583          * For DFS root mounts, the prefix path (cifs_sb->prepath) is preserved during reconnect so
3584          * only the root path is set in cifs_sb->origin_fullpath and tcon->dfs_path. And for DFS
3585          * links, the prefix path is included in both and may be changed during reconnect.  See
3586          * cifs_tree_connect().
3587          */
3588         ref_path = dfs_cache_canonical_path(full_path, cifs_sb->local_nls, cifs_remap(cifs_sb));
3589         kfree(full_path);
3590         full_path = NULL;
3591
3592         if (IS_ERR(ref_path)) {
3593                 rc = PTR_ERR(ref_path);
3594                 ref_path = NULL;
3595                 goto error;
3596         }
3597         cifs_sb->origin_fullpath = ref_path;
3598
3599         ref_path = kstrdup(cifs_sb->origin_fullpath, GFP_KERNEL);
3600         if (!ref_path) {
3601                 rc = -ENOMEM;
3602                 goto error;
3603         }
3604         spin_lock(&cifs_tcp_ses_lock);
3605         tcon->dfs_path = ref_path;
3606         ref_path = NULL;
3607         spin_unlock(&cifs_tcp_ses_lock);
3608
3609         /*
3610          * After reconnecting to a different server, unique ids won't
3611          * match anymore, so we disable serverino. This prevents
3612          * dentry revalidation to think the dentry are stale (ESTALE).
3613          */
3614         cifs_autodisable_serverino(cifs_sb);
3615         /*
3616          * Force the use of prefix path to support failover on DFS paths that
3617          * resolve to targets that have different prefix paths.
3618          */
3619         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3620         kfree(cifs_sb->prepath);
3621         cifs_sb->prepath = ctx->prepath;
3622         ctx->prepath = NULL;
3623         uuid_copy(&cifs_sb->dfs_mount_id, &mount_id);
3624
3625 out:
3626         free_xid(xid);
3627         cifs_try_adding_channels(cifs_sb, ses);
3628         return mount_setup_tlink(cifs_sb, ses, tcon);
3629
3630 error:
3631         kfree(ref_path);
3632         kfree(full_path);
3633         kfree(cifs_sb->origin_fullpath);
3634         dfs_cache_put_refsrv_sessions(&mount_id);
3635         mount_put_conns(cifs_sb, xid, server, ses, tcon);
3636         return rc;
3637 }
3638 #else
3639 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3640 {
3641         int rc = 0;
3642         unsigned int xid;
3643         struct cifs_ses *ses;
3644         struct cifs_tcon *tcon;
3645         struct TCP_Server_Info *server;
3646
3647         rc = mount_get_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
3648         if (rc)
3649                 goto error;
3650
3651         if (tcon) {
3652                 rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
3653                 if (rc == -EREMOTE)
3654                         rc = -EOPNOTSUPP;
3655                 if (rc)
3656                         goto error;
3657         }
3658
3659         free_xid(xid);
3660
3661         return mount_setup_tlink(cifs_sb, ses, tcon);
3662
3663 error:
3664         mount_put_conns(cifs_sb, xid, server, ses, tcon);
3665         return rc;
3666 }
3667 #endif
3668
3669 /*
3670  * Issue a TREE_CONNECT request.
3671  */
3672 int
3673 CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
3674          const char *tree, struct cifs_tcon *tcon,
3675          const struct nls_table *nls_codepage)
3676 {
3677         struct smb_hdr *smb_buffer;
3678         struct smb_hdr *smb_buffer_response;
3679         TCONX_REQ *pSMB;
3680         TCONX_RSP *pSMBr;
3681         unsigned char *bcc_ptr;
3682         int rc = 0;
3683         int length;
3684         __u16 bytes_left, count;
3685
3686         if (ses == NULL)
3687                 return -EIO;
3688
3689         smb_buffer = cifs_buf_get();
3690         if (smb_buffer == NULL)
3691                 return -ENOMEM;
3692
3693         smb_buffer_response = smb_buffer;
3694
3695         header_assemble(smb_buffer, SMB_COM_TREE_CONNECT_ANDX,
3696                         NULL /*no tid */ , 4 /*wct */ );
3697
3698         smb_buffer->Mid = get_next_mid(ses->server);
3699         smb_buffer->Uid = ses->Suid;
3700         pSMB = (TCONX_REQ *) smb_buffer;
3701         pSMBr = (TCONX_RSP *) smb_buffer_response;
3702
3703         pSMB->AndXCommand = 0xFF;
3704         pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
3705         bcc_ptr = &pSMB->Password[0];
3706         if (tcon->pipe || (ses->server->sec_mode & SECMODE_USER)) {
3707                 pSMB->PasswordLength = cpu_to_le16(1);  /* minimum */
3708                 *bcc_ptr = 0; /* password is null byte */
3709                 bcc_ptr++;              /* skip password */
3710                 /* already aligned so no need to do it below */
3711         }
3712
3713         if (ses->server->sign)
3714                 smb_buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
3715
3716         if (ses->capabilities & CAP_STATUS32) {
3717                 smb_buffer->Flags2 |= SMBFLG2_ERR_STATUS;
3718         }
3719         if (ses->capabilities & CAP_DFS) {
3720                 smb_buffer->Flags2 |= SMBFLG2_DFS;
3721         }
3722         if (ses->capabilities & CAP_UNICODE) {
3723                 smb_buffer->Flags2 |= SMBFLG2_UNICODE;
3724                 length =
3725                     cifs_strtoUTF16((__le16 *) bcc_ptr, tree,
3726                         6 /* max utf8 char length in bytes */ *
3727                         (/* server len*/ + 256 /* share len */), nls_codepage);
3728                 bcc_ptr += 2 * length;  /* convert num 16 bit words to bytes */
3729                 bcc_ptr += 2;   /* skip trailing null */
3730         } else {                /* ASCII */
3731                 strcpy(bcc_ptr, tree);
3732                 bcc_ptr += strlen(tree) + 1;
3733         }
3734         strcpy(bcc_ptr, "?????");
3735         bcc_ptr += strlen("?????");
3736         bcc_ptr += 1;
3737         count = bcc_ptr - &pSMB->Password[0];
3738         be32_add_cpu(&pSMB->hdr.smb_buf_length, count);
3739         pSMB->ByteCount = cpu_to_le16(count);
3740
3741         rc = SendReceive(xid, ses, smb_buffer, smb_buffer_response, &length,
3742                          0);
3743
3744         /* above now done in SendReceive */
3745         if (rc == 0) {
3746                 bool is_unicode;
3747
3748                 tcon->tidStatus = CifsGood;
3749                 tcon->need_reconnect = false;
3750                 tcon->tid = smb_buffer_response->Tid;
3751                 bcc_ptr = pByteArea(smb_buffer_response);
3752                 bytes_left = get_bcc(smb_buffer_response);
3753                 length = strnlen(bcc_ptr, bytes_left - 2);
3754                 if (smb_buffer->Flags2 & SMBFLG2_UNICODE)
3755                         is_unicode = true;
3756                 else
3757                         is_unicode = false;
3758
3759
3760                 /* skip service field (NB: this field is always ASCII) */
3761                 if (length == 3) {
3762                         if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
3763                             (bcc_ptr[2] == 'C')) {
3764                                 cifs_dbg(FYI, "IPC connection\n");
3765                                 tcon->ipc = true;
3766                                 tcon->pipe = true;
3767                         }
3768                 } else if (length == 2) {
3769                         if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {
3770                                 /* the most common case */
3771                                 cifs_dbg(FYI, "disk share connection\n");
3772                         }
3773                 }
3774                 bcc_ptr += length + 1;
3775                 bytes_left -= (length + 1);
3776                 strlcpy(tcon->treeName, tree, sizeof(tcon->treeName));
3777
3778                 /* mostly informational -- no need to fail on error here */
3779                 kfree(tcon->nativeFileSystem);
3780                 tcon->nativeFileSystem = cifs_strndup_from_utf16(bcc_ptr,
3781                                                       bytes_left, is_unicode,
3782                                                       nls_codepage);
3783
3784                 cifs_dbg(FYI, "nativeFileSystem=%s\n", tcon->nativeFileSystem);
3785
3786                 if ((smb_buffer_response->WordCount == 3) ||
3787                          (smb_buffer_response->WordCount == 7))
3788                         /* field is in same location */
3789                         tcon->Flags = le16_to_cpu(pSMBr->OptionalSupport);
3790                 else
3791                         tcon->Flags = 0;
3792                 cifs_dbg(FYI, "Tcon flags: 0x%x\n", tcon->Flags);
3793         }
3794
3795         cifs_buf_release(smb_buffer);
3796         return rc;
3797 }
3798
3799 static void delayed_free(struct rcu_head *p)
3800 {
3801         struct cifs_sb_info *cifs_sb = container_of(p, struct cifs_sb_info, rcu);
3802
3803         unload_nls(cifs_sb->local_nls);
3804         smb3_cleanup_fs_context(cifs_sb->ctx);
3805         kfree(cifs_sb);
3806 }
3807
3808 void
3809 cifs_umount(struct cifs_sb_info *cifs_sb)
3810 {
3811         struct rb_root *root = &cifs_sb->tlink_tree;
3812         struct rb_node *node;
3813         struct tcon_link *tlink;
3814
3815         cancel_delayed_work_sync(&cifs_sb->prune_tlinks);
3816
3817         spin_lock(&cifs_sb->tlink_tree_lock);
3818         while ((node = rb_first(root))) {
3819                 tlink = rb_entry(node, struct tcon_link, tl_rbnode);
3820                 cifs_get_tlink(tlink);
3821                 clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3822                 rb_erase(node, root);
3823
3824                 spin_unlock(&cifs_sb->tlink_tree_lock);
3825                 cifs_put_tlink(tlink);
3826                 spin_lock(&cifs_sb->tlink_tree_lock);
3827         }
3828         spin_unlock(&cifs_sb->tlink_tree_lock);
3829
3830         kfree(cifs_sb->prepath);
3831 #ifdef CONFIG_CIFS_DFS_UPCALL
3832         dfs_cache_put_refsrv_sessions(&cifs_sb->dfs_mount_id);
3833         kfree(cifs_sb->origin_fullpath);
3834 #endif
3835         call_rcu(&cifs_sb->rcu, delayed_free);
3836 }
3837
3838 int
3839 cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses)
3840 {
3841         int rc = 0;
3842         struct TCP_Server_Info *server = cifs_ses_server(ses);
3843
3844         if (!server->ops->need_neg || !server->ops->negotiate)
3845                 return -ENOSYS;
3846
3847         /* only send once per connect */
3848         if (!server->ops->need_neg(server))
3849                 return 0;
3850
3851         rc = server->ops->negotiate(xid, ses);
3852         if (rc == 0) {
3853                 spin_lock(&GlobalMid_Lock);
3854                 if (server->tcpStatus == CifsNeedNegotiate)
3855                         server->tcpStatus = CifsGood;
3856                 else
3857                         rc = -EHOSTDOWN;
3858                 spin_unlock(&GlobalMid_Lock);
3859         }
3860
3861         return rc;
3862 }
3863
3864 int
3865 cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
3866                    struct nls_table *nls_info)
3867 {
3868         int rc = -ENOSYS;
3869         struct TCP_Server_Info *server = cifs_ses_server(ses);
3870
3871         if (!ses->binding) {
3872                 ses->capabilities = server->capabilities;
3873                 if (!linuxExtEnabled)
3874                         ses->capabilities &= (~server->vals->cap_unix);
3875
3876                 if (ses->auth_key.response) {
3877                         cifs_dbg(FYI, "Free previous auth_key.response = %p\n",
3878                                  ses->auth_key.response);
3879                         kfree(ses->auth_key.response);
3880                         ses->auth_key.response = NULL;
3881                         ses->auth_key.len = 0;
3882                 }
3883         }
3884
3885         cifs_dbg(FYI, "Security Mode: 0x%x Capabilities: 0x%x TimeAdjust: %d\n",
3886                  server->sec_mode, server->capabilities, server->timeAdj);
3887
3888         if (server->ops->sess_setup)
3889                 rc = server->ops->sess_setup(xid, ses, nls_info);
3890
3891         if (rc)
3892                 cifs_server_dbg(VFS, "Send error in SessSetup = %d\n", rc);
3893
3894         return rc;
3895 }
3896
3897 static int
3898 cifs_set_vol_auth(struct smb3_fs_context *ctx, struct cifs_ses *ses)
3899 {
3900         ctx->sectype = ses->sectype;
3901
3902         /* krb5 is special, since we don't need username or pw */
3903         if (ctx->sectype == Kerberos)
3904                 return 0;
3905
3906         return cifs_set_cifscreds(ctx, ses);
3907 }
3908
3909 static struct cifs_tcon *
3910 cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
3911 {
3912         int rc;
3913         struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
3914         struct cifs_ses *ses;
3915         struct cifs_tcon *tcon = NULL;
3916         struct smb3_fs_context *ctx;
3917
3918         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
3919         if (ctx == NULL)
3920                 return ERR_PTR(-ENOMEM);
3921
3922         ctx->local_nls = cifs_sb->local_nls;
3923         ctx->linux_uid = fsuid;
3924         ctx->cred_uid = fsuid;
3925         ctx->UNC = master_tcon->treeName;
3926         ctx->retry = master_tcon->retry;
3927         ctx->nocase = master_tcon->nocase;
3928         ctx->nohandlecache = master_tcon->nohandlecache;
3929         ctx->local_lease = master_tcon->local_lease;
3930         ctx->no_lease = master_tcon->no_lease;
3931         ctx->resilient = master_tcon->use_resilient;
3932         ctx->persistent = master_tcon->use_persistent;
3933         ctx->handle_timeout = master_tcon->handle_timeout;
3934         ctx->no_linux_ext = !master_tcon->unix_ext;
3935         ctx->linux_ext = master_tcon->posix_extensions;
3936         ctx->sectype = master_tcon->ses->sectype;
3937         ctx->sign = master_tcon->ses->sign;
3938         ctx->seal = master_tcon->seal;
3939         ctx->witness = master_tcon->use_witness;
3940
3941         rc = cifs_set_vol_auth(ctx, master_tcon->ses);
3942         if (rc) {
3943                 tcon = ERR_PTR(rc);
3944                 goto out;
3945         }
3946
3947         /* get a reference for the same TCP session */
3948         spin_lock(&cifs_tcp_ses_lock);
3949         ++master_tcon->ses->server->srv_count;
3950         spin_unlock(&cifs_tcp_ses_lock);
3951
3952         ses = cifs_get_smb_ses(master_tcon->ses->server, ctx);
3953         if (IS_ERR(ses)) {
3954                 tcon = (struct cifs_tcon *)ses;
3955                 cifs_put_tcp_session(master_tcon->ses->server, 0);
3956                 goto out;
3957         }
3958
3959         tcon = cifs_get_tcon(ses, ctx);
3960         if (IS_ERR(tcon)) {
3961                 cifs_put_smb_ses(ses);
3962                 goto out;
3963         }
3964
3965         if (cap_unix(ses))
3966                 reset_cifs_unix_caps(0, tcon, NULL, ctx);
3967
3968 out:
3969         kfree(ctx->username);
3970         kfree_sensitive(ctx->password);
3971         kfree(ctx);
3972
3973         return tcon;
3974 }
3975
3976 struct cifs_tcon *
3977 cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
3978 {
3979         return tlink_tcon(cifs_sb_master_tlink(cifs_sb));
3980 }
3981
3982 /* find and return a tlink with given uid */
3983 static struct tcon_link *
3984 tlink_rb_search(struct rb_root *root, kuid_t uid)
3985 {
3986         struct rb_node *node = root->rb_node;
3987         struct tcon_link *tlink;
3988
3989         while (node) {
3990                 tlink = rb_entry(node, struct tcon_link, tl_rbnode);
3991
3992                 if (uid_gt(tlink->tl_uid, uid))
3993                         node = node->rb_left;
3994                 else if (uid_lt(tlink->tl_uid, uid))
3995                         node = node->rb_right;
3996                 else
3997                         return tlink;
3998         }
3999         return NULL;
4000 }
4001
4002 /* insert a tcon_link into the tree */
4003 static void
4004 tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink)
4005 {
4006         struct rb_node **new = &(root->rb_node), *parent = NULL;
4007         struct tcon_link *tlink;
4008
4009         while (*new) {
4010                 tlink = rb_entry(*new, struct tcon_link, tl_rbnode);
4011                 parent = *new;
4012
4013                 if (uid_gt(tlink->tl_uid, new_tlink->tl_uid))
4014                         new = &((*new)->rb_left);
4015                 else
4016                         new = &((*new)->rb_right);
4017         }
4018
4019         rb_link_node(&new_tlink->tl_rbnode, parent, new);
4020         rb_insert_color(&new_tlink->tl_rbnode, root);
4021 }
4022
4023 /*
4024  * Find or construct an appropriate tcon given a cifs_sb and the fsuid of the
4025  * current task.
4026  *
4027  * If the superblock doesn't refer to a multiuser mount, then just return
4028  * the master tcon for the mount.
4029  *
4030  * First, search the rbtree for an existing tcon for this fsuid. If one
4031  * exists, then check to see if it's pending construction. If it is then wait
4032  * for construction to complete. Once it's no longer pending, check to see if
4033  * it failed and either return an error or retry construction, depending on
4034  * the timeout.
4035  *
4036  * If one doesn't exist then insert a new tcon_link struct into the tree and
4037  * try to construct a new one.
4038  */
4039 struct tcon_link *
4040 cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
4041 {
4042         int ret;
4043         kuid_t fsuid = current_fsuid();
4044         struct tcon_link *tlink, *newtlink;
4045
4046         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
4047                 return cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
4048
4049         spin_lock(&cifs_sb->tlink_tree_lock);
4050         tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4051         if (tlink)
4052                 cifs_get_tlink(tlink);
4053         spin_unlock(&cifs_sb->tlink_tree_lock);
4054
4055         if (tlink == NULL) {
4056                 newtlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
4057                 if (newtlink == NULL)
4058                         return ERR_PTR(-ENOMEM);
4059                 newtlink->tl_uid = fsuid;
4060                 newtlink->tl_tcon = ERR_PTR(-EACCES);
4061                 set_bit(TCON_LINK_PENDING, &newtlink->tl_flags);
4062                 set_bit(TCON_LINK_IN_TREE, &newtlink->tl_flags);
4063                 cifs_get_tlink(newtlink);
4064
4065                 spin_lock(&cifs_sb->tlink_tree_lock);
4066                 /* was one inserted after previous search? */
4067                 tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4068                 if (tlink) {
4069                         cifs_get_tlink(tlink);
4070                         spin_unlock(&cifs_sb->tlink_tree_lock);
4071                         kfree(newtlink);
4072                         goto wait_for_construction;
4073                 }
4074                 tlink = newtlink;
4075                 tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
4076                 spin_unlock(&cifs_sb->tlink_tree_lock);
4077         } else {
4078 wait_for_construction:
4079                 ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
4080                                   TASK_INTERRUPTIBLE);
4081                 if (ret) {
4082                         cifs_put_tlink(tlink);
4083                         return ERR_PTR(-ERESTARTSYS);
4084                 }
4085
4086                 /* if it's good, return it */
4087                 if (!IS_ERR(tlink->tl_tcon))
4088                         return tlink;
4089
4090                 /* return error if we tried this already recently */
4091                 if (time_before(jiffies, tlink->tl_time + TLINK_ERROR_EXPIRE)) {
4092                         cifs_put_tlink(tlink);
4093                         return ERR_PTR(-EACCES);
4094                 }
4095
4096                 if (test_and_set_bit(TCON_LINK_PENDING, &tlink->tl_flags))
4097                         goto wait_for_construction;
4098         }
4099
4100         tlink->tl_tcon = cifs_construct_tcon(cifs_sb, fsuid);
4101         clear_bit(TCON_LINK_PENDING, &tlink->tl_flags);
4102         wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING);
4103
4104         if (IS_ERR(tlink->tl_tcon)) {
4105                 cifs_put_tlink(tlink);
4106                 return ERR_PTR(-EACCES);
4107         }
4108
4109         return tlink;
4110 }
4111
4112 /*
4113  * periodic workqueue job that scans tcon_tree for a superblock and closes
4114  * out tcons.
4115  */
4116 static void
4117 cifs_prune_tlinks(struct work_struct *work)
4118 {
4119         struct cifs_sb_info *cifs_sb = container_of(work, struct cifs_sb_info,
4120                                                     prune_tlinks.work);
4121         struct rb_root *root = &cifs_sb->tlink_tree;
4122         struct rb_node *node;
4123         struct rb_node *tmp;
4124         struct tcon_link *tlink;
4125
4126         /*
4127          * Because we drop the spinlock in the loop in order to put the tlink
4128          * it's not guarded against removal of links from the tree. The only
4129          * places that remove entries from the tree are this function and
4130          * umounts. Because this function is non-reentrant and is canceled
4131          * before umount can proceed, this is safe.
4132          */
4133         spin_lock(&cifs_sb->tlink_tree_lock);
4134         node = rb_first(root);
4135         while (node != NULL) {
4136                 tmp = node;
4137                 node = rb_next(tmp);
4138                 tlink = rb_entry(tmp, struct tcon_link, tl_rbnode);
4139
4140                 if (test_bit(TCON_LINK_MASTER, &tlink->tl_flags) ||
4141                     atomic_read(&tlink->tl_count) != 0 ||
4142                     time_after(tlink->tl_time + TLINK_IDLE_EXPIRE, jiffies))
4143                         continue;
4144
4145                 cifs_get_tlink(tlink);
4146                 clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
4147                 rb_erase(tmp, root);
4148
4149                 spin_unlock(&cifs_sb->tlink_tree_lock);
4150                 cifs_put_tlink(tlink);
4151                 spin_lock(&cifs_sb->tlink_tree_lock);
4152         }
4153         spin_unlock(&cifs_sb->tlink_tree_lock);
4154
4155         queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
4156                                 TLINK_IDLE_EXPIRE);
4157 }
4158
4159 #ifdef CONFIG_CIFS_DFS_UPCALL
4160 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
4161 {
4162         int rc;
4163         struct TCP_Server_Info *server = tcon->ses->server;
4164         const struct smb_version_operations *ops = server->ops;
4165         struct dfs_cache_tgt_list tl;
4166         struct dfs_cache_tgt_iterator *it = NULL;
4167         char *tree;
4168         const char *tcp_host;
4169         size_t tcp_host_len;
4170         const char *dfs_host;
4171         size_t dfs_host_len;
4172         char *share = NULL, *prefix = NULL;
4173         struct dfs_info3_param ref = {0};
4174         bool isroot;
4175
4176         tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
4177         if (!tree)
4178                 return -ENOMEM;
4179
4180         /* If it is not dfs or there was no cached dfs referral, then reconnect to same share */
4181         if (!tcon->dfs_path || dfs_cache_noreq_find(tcon->dfs_path + 1, &ref, &tl)) {
4182                 if (tcon->ipc) {
4183                         scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
4184                         rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
4185                 } else {
4186                         rc = ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
4187                 }
4188                 goto out;
4189         }
4190
4191         isroot = ref.server_type == DFS_TYPE_ROOT;
4192         free_dfs_info_param(&ref);
4193
4194         extract_unc_hostname(server->hostname, &tcp_host, &tcp_host_len);
4195
4196         for (it = dfs_cache_get_tgt_iterator(&tl); it; it = dfs_cache_get_next_tgt(&tl, it)) {
4197                 bool target_match;
4198
4199                 kfree(share);
4200                 kfree(prefix);
4201                 share = NULL;
4202                 prefix = NULL;
4203
4204                 rc = dfs_cache_get_tgt_share(tcon->dfs_path + 1, it, &share, &prefix);
4205                 if (rc) {
4206                         cifs_dbg(VFS, "%s: failed to parse target share %d\n",
4207                                  __func__, rc);
4208                         continue;
4209                 }
4210
4211                 extract_unc_hostname(share, &dfs_host, &dfs_host_len);
4212
4213                 if (dfs_host_len != tcp_host_len
4214                     || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {
4215                         cifs_dbg(FYI, "%s: %.*s doesn't match %.*s\n", __func__, (int)dfs_host_len,
4216                                  dfs_host, (int)tcp_host_len, tcp_host);
4217
4218                         rc = match_target_ip(server, dfs_host, dfs_host_len, &target_match);
4219                         if (rc) {
4220                                 cifs_dbg(VFS, "%s: failed to match target ip: %d\n", __func__, rc);
4221                                 break;
4222                         }
4223
4224                         if (!target_match) {
4225                                 cifs_dbg(FYI, "%s: skipping target\n", __func__);
4226                                 continue;
4227                         }
4228                 }
4229
4230                 if (tcon->ipc) {
4231                         scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", share);
4232                         rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
4233                 } else {
4234                         scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
4235                         rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
4236                         /* Only handle prefix paths of DFS link targets */
4237                         if (!rc && !isroot) {
4238                                 rc = update_super_prepath(tcon, prefix);
4239                                 break;
4240                         }
4241                 }
4242                 if (rc == -EREMOTE)
4243                         break;
4244         }
4245
4246         kfree(share);
4247         kfree(prefix);
4248
4249         if (!rc) {
4250                 if (it)
4251                         rc = dfs_cache_noreq_update_tgthint(tcon->dfs_path + 1, it);
4252                 else
4253                         rc = -ENOENT;
4254         }
4255         dfs_cache_free_tgts(&tl);
4256 out:
4257         kfree(tree);
4258         return rc;
4259 }
4260 #else
4261 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
4262 {
4263         const struct smb_version_operations *ops = tcon->ses->server->ops;
4264
4265         return ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
4266 }
4267 #endif