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 = max_t(unsigned long, expiry - now, SMB_DNS_RESOLVE_INTERVAL_MIN) + 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 /**
 152  * Mark all sessions and tcons for reconnect.
 153  *
 154  * @server needs to be previously set to CifsNeedReconnect.
 155  */
 156 static void cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server)
 157 {
 158         struct cifs_ses *ses;
 159         struct cifs_tcon *tcon;
 160         struct mid_q_entry *mid, *nmid;
 161         struct list_head retry_list;
 162
 163         server->maxBuf = 0;
 164         server->max_read = 0;
 165
 166         cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
 167         trace_smb3_reconnect(server->CurrentMid, server->conn_id, server->hostname);
 168         /*
 169          * before reconnecting the tcp session, mark the smb session (uid) and the tid bad so they
 170          * are not used until reconnected.
 171          */
 172         cifs_dbg(FYI, "%s: marking sessions and tcons for reconnect\n", __func__);
 173         spin_lock(&cifs_tcp_ses_lock);
 174         list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
 175                 ses->need_reconnect = true;
 176                 list_for_each_entry(tcon, &ses->tcon_list, tcon_list)
 177                         tcon->need_reconnect = true;
 178                 if (ses->tcon_ipc)
 179                         ses->tcon_ipc->need_reconnect = true;
 180         }
 181         spin_unlock(&cifs_tcp_ses_lock);
 182
 183         /* do not want to be sending data on a socket we are freeing */
 184         cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
 185         mutex_lock(&server->srv_mutex);
 186         if (server->ssocket) {
 187                 cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n", server->ssocket->state,
 188                          server->ssocket->flags);
 189                 kernel_sock_shutdown(server->ssocket, SHUT_WR);
 190                 cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n", server->ssocket->state,
 191                          server->ssocket->flags);
 192                 sock_release(server->ssocket);
 193                 server->ssocket = NULL;
 194         }
 195         server->sequence_number = 0;
 196         server->session_estab = false;
 197         kfree(server->session_key.response);
 198         server->session_key.response = NULL;
 199         server->session_key.len = 0;
 200         server->lstrp = jiffies;
 201
 202         /* mark submitted MIDs for retry and issue callback */
 203         INIT_LIST_HEAD(&retry_list);
 204         cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
 205         spin_lock(&GlobalMid_Lock);
 206         list_for_each_entry_safe(mid, nmid, &server->pending_mid_q, qhead) {
 207                 kref_get(&mid->refcount);
 208                 if (mid->mid_state == MID_REQUEST_SUBMITTED)
 209                         mid->mid_state = MID_RETRY_NEEDED;
 210                 list_move(&mid->qhead, &retry_list);
 211                 mid->mid_flags |= MID_DELETED;
 212         }
 213         spin_unlock(&GlobalMid_Lock);
 214         mutex_unlock(&server->srv_mutex);
 215
 216         cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
 217         list_for_each_entry_safe(mid, nmid, &retry_list, qhead) {
 218                 list_del_init(&mid->qhead);
 219                 mid->callback(mid);
 220                 cifs_mid_q_entry_release(mid);
 221         }
 222
 223         if (cifs_rdma_enabled(server)) {
 224                 mutex_lock(&server->srv_mutex);
 225                 smbd_destroy(server);
 226                 mutex_unlock(&server->srv_mutex);
 227         }
 228 }
 229
 230 static bool cifs_tcp_ses_needs_reconnect(struct TCP_Server_Info *server, int num_targets)
 231 {
 232         spin_lock(&GlobalMid_Lock);
 233         server->nr_targets = num_targets;
 234         if (server->tcpStatus == CifsExiting) {
 235                 /* the demux thread will exit normally next time through the loop */
 236                 spin_unlock(&GlobalMid_Lock);
 237                 wake_up(&server->response_q);
 238                 return false;
 239         }
 240         server->tcpStatus = CifsNeedReconnect;
 241         spin_unlock(&GlobalMid_Lock);
 242         return true;
 243 }
 244
 245 /*
 246  * cifs tcp session reconnection
 247  *
 248  * mark tcp session as reconnecting so temporarily locked
 249  * mark all smb sessions as reconnecting for tcp session
 250  * reconnect tcp session
 251  * wake up waiters on reconnection? - (not needed currently)
 252  */
 253 static int __cifs_reconnect(struct TCP_Server_Info *server)
 254 {
 255         int rc = 0;
 256
 257         if (!cifs_tcp_ses_needs_reconnect(server, 1))
 258                 return 0;
 259
 260         cifs_mark_tcp_ses_conns_for_reconnect(server);
 261
 262         do {
 263                 try_to_freeze();
 264                 mutex_lock(&server->srv_mutex);
 265
 266                 if (!cifs_swn_set_server_dstaddr(server)) {
 267                         /* resolve the hostname again to make sure that IP address is up-to-date */
 268                         rc = reconn_set_ipaddr_from_hostname(server);
 269                         cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
 270                 }
 271
 272                 if (cifs_rdma_enabled(server))
 273                         rc = smbd_reconnect(server);
 274                 else
 275                         rc = generic_ip_connect(server);
 276                 if (rc) {
 277                         mutex_unlock(&server->srv_mutex);
 278                         cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
 279                         msleep(3000);
 280                 } else {
 281                         atomic_inc(&tcpSesReconnectCount);
 282                         set_credits(server, 1);
 283                         spin_lock(&GlobalMid_Lock);
 284                         if (server->tcpStatus != CifsExiting)
 285                                 server->tcpStatus = CifsNeedNegotiate;
 286                         spin_unlock(&GlobalMid_Lock);
 287                         cifs_swn_reset_server_dstaddr(server);
 288                         mutex_unlock(&server->srv_mutex);
 289                 }
 290         } while (server->tcpStatus == CifsNeedReconnect);
 291
 292         if (server->tcpStatus == CifsNeedNegotiate)
 293                 mod_delayed_work(cifsiod_wq, &server->echo, 0);
 294
 295         wake_up(&server->response_q);
 296         return rc;
 297 }
 298
 299 #ifdef CONFIG_CIFS_DFS_UPCALL
 300 static int reconnect_dfs_server(struct TCP_Server_Info *server, struct cifs_sb_info *cifs_sb)
 301 {
 302         int rc = 0;
 303         const char *refpath = cifs_sb->origin_fullpath + 1;
 304         struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
 305         struct dfs_cache_tgt_iterator *tit = NULL;
 306         int num_targets = 1;
 307         char *hostname;
 308
 309         /*
 310          * Determine the number of dfs targets the referral path in @cifs_sb resolves to.
 311          *
 312          * smb2_reconnect() needs to know how long it should wait based upon the number of dfs
 313          * targets (server->nr_targets).  It's also possible that the cached referral was cleared
 314          * through /proc/fs/cifs/dfscache or the target list is empty due to server settings after
 315          * refreshing the referral, so, in this case, default it to 1.
 316          */
 317         if (!dfs_cache_noreq_find(refpath, NULL, &tl)) {
 318                 num_targets = dfs_cache_get_nr_tgts(&tl);
 319                 if (!num_targets)
 320                         num_targets = 1;
 321         }
 322
 323         if (!cifs_tcp_ses_needs_reconnect(server, num_targets))
 324                 return 0;
 325
 326         cifs_mark_tcp_ses_conns_for_reconnect(server);
 327
 328         do {
 329                 /* Get next dfs target from target list (if any) */
 330                 if (!tit)
 331                         tit = dfs_cache_get_tgt_iterator(&tl);
 332                 else
 333                         tit = dfs_cache_get_next_tgt(&tl, tit);
 334
 335                 try_to_freeze();
 336                 mutex_lock(&server->srv_mutex);
 337
 338                 if (!cifs_swn_set_server_dstaddr(server)) {
 339                         /*
 340                          * If any dfs target was selected, then update @server with either a
 341                          * hostname or an address.
 342                          */
 343                         if (tit) {
 344                                 hostname = extract_hostname(dfs_cache_get_tgt_name(tit));
 345                                 if (!IS_ERR(hostname)) {
 346                                         kfree(server->hostname);
 347                                         server->hostname = hostname;
 348                                 } else {
 349                                         cifs_dbg(FYI, "%s: couldn't extract hostname or address from dfs target: %ld\n",
 350                                                  __func__, PTR_ERR(hostname));
 351                                         cifs_dbg(FYI, "%s: default to last target server: %s\n",
 352                                                  __func__, server->hostname);
 353                                 }
 354                         }
 355                         /* resolve the hostname again to make sure that IP address is up-to-date. */
 356                         rc = reconn_set_ipaddr_from_hostname(server);
 357                         cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
 358                 }
 359
 360                 /* Reconnect the socket */
 361                 if (cifs_rdma_enabled(server))
 362                         rc = smbd_reconnect(server);
 363                 else
 364                         rc = generic_ip_connect(server);
 365
 366                 if (rc) {
 367                         /* Failed to reconnect socket.  Retry next dfs target. */
 368                         mutex_unlock(&server->srv_mutex);
 369                         cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
 370                         msleep(3000);
 371                         continue;
 372                 }
 373
 374                 /*
 375                  * Socket was created.  Update tcp session status to CifsNeedNegotiate so that a
 376                  * process waiting for reconnect will know it needs to re-establish session and tcon
 377                  * through the reconnected target server.
 378                  */
 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         } while (server->tcpStatus == CifsNeedReconnect);
 388
 389         if (tit)
 390                 dfs_cache_noreq_update_tgthint(refpath, tit);
 391
 392         dfs_cache_free_tgts(&tl);
 393
 394         /* Need to set up echo worker again once connection has been established */
 395         if (server->tcpStatus == CifsNeedNegotiate)
 396                 mod_delayed_work(cifsiod_wq, &server->echo, 0);
 397
 398         wake_up(&server->response_q);
 399         return rc;
 400 }
 401
 402 int cifs_reconnect(struct TCP_Server_Info *server)
 403 {
 404         int rc;
 405         struct super_block *sb;
 406         struct cifs_sb_info *cifs_sb;
 407
 408         /*
 409          * If tcp session is not an dfs connection or it is a channel, then reconnect to last target
 410          * server.
 411          */
 412         spin_lock(&cifs_tcp_ses_lock);
 413         if (!server->is_dfs_conn || server->is_channel) {
 414                 spin_unlock(&cifs_tcp_ses_lock);
 415                 return __cifs_reconnect(server);
 416         }
 417         spin_unlock(&cifs_tcp_ses_lock);
 418
 419         /* If no superblock, then it might be an ipc connection */
 420         sb = cifs_get_tcp_super(server);
 421         if (IS_ERR(sb))
 422                 return __cifs_reconnect(server);
 423
 424         /*
 425          * Check for a referral path to look up in superblock.  If unset, then simply reconnect to
 426          * last target server.
 427          */
 428         cifs_sb = CIFS_SB(sb);
 429         if (!cifs_sb->origin_fullpath || !cifs_sb->origin_fullpath[0])
 430                 rc = __cifs_reconnect(server);
 431         else
 432                 rc = reconnect_dfs_server(server, cifs_sb);
 433
 434         cifs_put_tcp_super(sb);
 435         return rc;
 436 }
 437 #else
 438 int cifs_reconnect(struct TCP_Server_Info *server)
 439 {
 440         return __cifs_reconnect(server);
 441 }
 442 #endif
 443
 444 static void
 445 cifs_echo_request(struct work_struct *work)
 446 {
 447         int rc;
 448         struct TCP_Server_Info *server = container_of(work,
 449                                         struct TCP_Server_Info, echo.work);
 450
 451         /*
 452          * We cannot send an echo if it is disabled.
 453          * Also, no need to ping if we got a response recently.
 454          */
 455
 456         if (server->tcpStatus == CifsNeedReconnect ||
 457             server->tcpStatus == CifsExiting ||
 458             server->tcpStatus == CifsNew ||
 459             (server->ops->can_echo && !server->ops->can_echo(server)) ||
 460             time_before(jiffies, server->lstrp + server->echo_interval - HZ))
 461                 goto requeue_echo;
 462
 463         rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
 464         if (rc)
 465                 cifs_dbg(FYI, "Unable to send echo request to server: %s\n",
 466                          server->hostname);
 467
 468         /* Check witness registrations */
 469         cifs_swn_check();
 470
 471 requeue_echo:
 472         queue_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
 473 }
 474
 475 static bool
 476 allocate_buffers(struct TCP_Server_Info *server)
 477 {
 478         if (!server->bigbuf) {
 479                 server->bigbuf = (char *)cifs_buf_get();
 480                 if (!server->bigbuf) {
 481                         cifs_server_dbg(VFS, "No memory for large SMB response\n");
 482                         msleep(3000);
 483                         /* retry will check if exiting */
 484                         return false;
 485                 }
 486         } else if (server->large_buf) {
 487                 /* we are reusing a dirty large buf, clear its start */
 488                 memset(server->bigbuf, 0, HEADER_SIZE(server));
 489         }
 490
 491         if (!server->smallbuf) {
 492                 server->smallbuf = (char *)cifs_small_buf_get();
 493                 if (!server->smallbuf) {
 494                         cifs_server_dbg(VFS, "No memory for SMB response\n");
 495                         msleep(1000);
 496                         /* retry will check if exiting */
 497                         return false;
 498                 }
 499                 /* beginning of smb buffer is cleared in our buf_get */
 500         } else {
 501                 /* if existing small buf clear beginning */
 502                 memset(server->smallbuf, 0, HEADER_SIZE(server));
 503         }
 504
 505         return true;
 506 }
 507
 508 static bool
 509 server_unresponsive(struct TCP_Server_Info *server)
 510 {
 511         /*
 512          * We need to wait 3 echo intervals to make sure we handle such
 513          * situations right:
 514          * 1s  client sends a normal SMB request
 515          * 2s  client gets a response
 516          * 30s echo workqueue job pops, and decides we got a response recently
 517          *     and don't need to send another
 518          * ...
 519          * 65s kernel_recvmsg times out, and we see that we haven't gotten
 520          *     a response in >60s.
 521          */
 522         if ((server->tcpStatus == CifsGood ||
 523             server->tcpStatus == CifsNeedNegotiate) &&
 524             (!server->ops->can_echo || server->ops->can_echo(server)) &&
 525             time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
 526                 cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
 527                          (3 * server->echo_interval) / HZ);
 528                 cifs_reconnect(server);
 529                 return true;
 530         }
 531
 532         return false;
 533 }
 534
 535 static inline bool
 536 zero_credits(struct TCP_Server_Info *server)
 537 {
 538         int val;
 539
 540         spin_lock(&server->req_lock);
 541         val = server->credits + server->echo_credits + server->oplock_credits;
 542         if (server->in_flight == 0 && val == 0) {
 543                 spin_unlock(&server->req_lock);
 544                 return true;
 545         }
 546         spin_unlock(&server->req_lock);
 547         return false;
 548 }
 549
 550 static int
 551 cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
 552 {
 553         int length = 0;
 554         int total_read;
 555
 556         smb_msg->msg_control = NULL;
 557         smb_msg->msg_controllen = 0;
 558
 559         for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
 560                 try_to_freeze();
 561
 562                 /* reconnect if no credits and no requests in flight */
 563                 if (zero_credits(server)) {
 564                         cifs_reconnect(server);
 565                         return -ECONNABORTED;
 566                 }
 567
 568                 if (server_unresponsive(server))
 569                         return -ECONNABORTED;
 570                 if (cifs_rdma_enabled(server) && server->smbd_conn)
 571                         length = smbd_recv(server->smbd_conn, smb_msg);
 572                 else
 573                         length = sock_recvmsg(server->ssocket, smb_msg, 0);
 574
 575                 if (server->tcpStatus == CifsExiting)
 576                         return -ESHUTDOWN;
 577
 578                 if (server->tcpStatus == CifsNeedReconnect) {
 579                         cifs_reconnect(server);
 580                         return -ECONNABORTED;
 581                 }
 582
 583                 if (length == -ERESTARTSYS ||
 584                     length == -EAGAIN ||
 585                     length == -EINTR) {
 586                         /*
 587                          * Minimum sleep to prevent looping, allowing socket
 588                          * to clear and app threads to set tcpStatus
 589                          * CifsNeedReconnect if server hung.
 590                          */
 591                         usleep_range(1000, 2000);
 592                         length = 0;
 593                         continue;
 594                 }
 595
 596                 if (length <= 0) {
 597                         cifs_dbg(FYI, "Received no data or error: %d\n", length);
 598                         cifs_reconnect(server);
 599                         return -ECONNABORTED;
 600                 }
 601         }
 602         return total_read;
 603 }
 604
 605 int
 606 cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
 607                       unsigned int to_read)
 608 {
 609         struct msghdr smb_msg;
 610         struct kvec iov = {.iov_base = buf, .iov_len = to_read};
 611         iov_iter_kvec(&smb_msg.msg_iter, READ, &iov, 1, to_read);
 612
 613         return cifs_readv_from_socket(server, &smb_msg);
 614 }
 615
 616 ssize_t
 617 cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
 618 {
 619         struct msghdr smb_msg;
 620
 621         /*
 622          *  iov_iter_discard already sets smb_msg.type and count and iov_offset
 623          *  and cifs_readv_from_socket sets msg_control and msg_controllen
 624          *  so little to initialize in struct msghdr
 625          */
 626         smb_msg.msg_name = NULL;
 627         smb_msg.msg_namelen = 0;
 628         iov_iter_discard(&smb_msg.msg_iter, READ, to_read);
 629
 630         return cifs_readv_from_socket(server, &smb_msg);
 631 }
 632
 633 int
 634 cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
 635         unsigned int page_offset, unsigned int to_read)
 636 {
 637         struct msghdr smb_msg;
 638         struct bio_vec bv = {
 639                 .bv_page = page, .bv_len = to_read, .bv_offset = page_offset};
 640         iov_iter_bvec(&smb_msg.msg_iter, READ, &bv, 1, to_read);
 641         return cifs_readv_from_socket(server, &smb_msg);
 642 }
 643
 644 static bool
 645 is_smb_response(struct TCP_Server_Info *server, unsigned char type)
 646 {
 647         /*
 648          * The first byte big endian of the length field,
 649          * is actually not part of the length but the type
 650          * with the most common, zero, as regular data.
 651          */
 652         switch (type) {
 653         case RFC1002_SESSION_MESSAGE:
 654                 /* Regular SMB response */
 655                 return true;
 656         case RFC1002_SESSION_KEEP_ALIVE:
 657                 cifs_dbg(FYI, "RFC 1002 session keep alive\n");
 658                 break;
 659         case RFC1002_POSITIVE_SESSION_RESPONSE:
 660                 cifs_dbg(FYI, "RFC 1002 positive session response\n");
 661                 break;
 662         case RFC1002_NEGATIVE_SESSION_RESPONSE:
 663                 /*
 664                  * We get this from Windows 98 instead of an error on
 665                  * SMB negprot response.
 666                  */
 667                 cifs_dbg(FYI, "RFC 1002 negative session response\n");
 668                 /* give server a second to clean up */
 669                 msleep(1000);
 670                 /*
 671                  * Always try 445 first on reconnect since we get NACK
 672                  * on some if we ever connected to port 139 (the NACK
 673                  * is since we do not begin with RFC1001 session
 674                  * initialize frame).
 675                  */
 676                 cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
 677                 cifs_reconnect(server);
 678                 break;
 679         default:
 680                 cifs_server_dbg(VFS, "RFC 1002 unknown response type 0x%x\n", type);
 681                 cifs_reconnect(server);
 682         }
 683
 684         return false;
 685 }
 686
 687 void
 688 dequeue_mid(struct mid_q_entry *mid, bool malformed)
 689 {
 690 #ifdef CONFIG_CIFS_STATS2
 691         mid->when_received = jiffies;
 692 #endif
 693         spin_lock(&GlobalMid_Lock);
 694         if (!malformed)
 695                 mid->mid_state = MID_RESPONSE_RECEIVED;
 696         else
 697                 mid->mid_state = MID_RESPONSE_MALFORMED;
 698         /*
 699          * Trying to handle/dequeue a mid after the send_recv()
 700          * function has finished processing it is a bug.
 701          */
 702         if (mid->mid_flags & MID_DELETED)
 703                 pr_warn_once("trying to dequeue a deleted mid\n");
 704         else {
 705                 list_del_init(&mid->qhead);
 706                 mid->mid_flags |= MID_DELETED;
 707         }
 708         spin_unlock(&GlobalMid_Lock);
 709 }
 710
 711 static unsigned int
 712 smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
 713 {
 714         struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
 715
 716         /*
 717          * SMB1 does not use credits.
 718          */
 719         if (server->vals->header_preamble_size)
 720                 return 0;
 721
 722         return le16_to_cpu(shdr->CreditRequest);
 723 }
 724
 725 static void
 726 handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 727            char *buf, int malformed)
 728 {
 729         if (server->ops->check_trans2 &&
 730             server->ops->check_trans2(mid, server, buf, malformed))
 731                 return;
 732         mid->credits_received = smb2_get_credits_from_hdr(buf, server);
 733         mid->resp_buf = buf;
 734         mid->large_buf = server->large_buf;
 735         /* Was previous buf put in mpx struct for multi-rsp? */
 736         if (!mid->multiRsp) {
 737                 /* smb buffer will be freed by user thread */
 738                 if (server->large_buf)
 739                         server->bigbuf = NULL;
 740                 else
 741                         server->smallbuf = NULL;
 742         }
 743         dequeue_mid(mid, malformed);
 744 }
 745
 746 static void clean_demultiplex_info(struct TCP_Server_Info *server)
 747 {
 748         int length;
 749
 750         /* take it off the list, if it's not already */
 751         spin_lock(&cifs_tcp_ses_lock);
 752         list_del_init(&server->tcp_ses_list);
 753         spin_unlock(&cifs_tcp_ses_lock);
 754
 755         cancel_delayed_work_sync(&server->echo);
 756         cancel_delayed_work_sync(&server->resolve);
 757
 758         spin_lock(&GlobalMid_Lock);
 759         server->tcpStatus = CifsExiting;
 760         spin_unlock(&GlobalMid_Lock);
 761         wake_up_all(&server->response_q);
 762
 763         /* check if we have blocked requests that need to free */
 764         spin_lock(&server->req_lock);
 765         if (server->credits <= 0)
 766                 server->credits = 1;
 767         spin_unlock(&server->req_lock);
 768         /*
 769          * Although there should not be any requests blocked on this queue it
 770          * can not hurt to be paranoid and try to wake up requests that may
 771          * haven been blocked when more than 50 at time were on the wire to the
 772          * same server - they now will see the session is in exit state and get
 773          * out of SendReceive.
 774          */
 775         wake_up_all(&server->request_q);
 776         /* give those requests time to exit */
 777         msleep(125);
 778         if (cifs_rdma_enabled(server))
 779                 smbd_destroy(server);
 780         if (server->ssocket) {
 781                 sock_release(server->ssocket);
 782                 server->ssocket = NULL;
 783         }
 784
 785         if (!list_empty(&server->pending_mid_q)) {
 786                 struct list_head dispose_list;
 787                 struct mid_q_entry *mid_entry;
 788                 struct list_head *tmp, *tmp2;
 789
 790                 INIT_LIST_HEAD(&dispose_list);
 791                 spin_lock(&GlobalMid_Lock);
 792                 list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
 793                         mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 794                         cifs_dbg(FYI, "Clearing mid %llu\n", mid_entry->mid);
 795                         kref_get(&mid_entry->refcount);
 796                         mid_entry->mid_state = MID_SHUTDOWN;
 797                         list_move(&mid_entry->qhead, &dispose_list);
 798                         mid_entry->mid_flags |= MID_DELETED;
 799                 }
 800                 spin_unlock(&GlobalMid_Lock);
 801
 802                 /* now walk dispose list and issue callbacks */
 803                 list_for_each_safe(tmp, tmp2, &dispose_list) {
 804                         mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 805                         cifs_dbg(FYI, "Callback mid %llu\n", mid_entry->mid);
 806                         list_del_init(&mid_entry->qhead);
 807                         mid_entry->callback(mid_entry);
 808                         cifs_mid_q_entry_release(mid_entry);
 809                 }
 810                 /* 1/8th of sec is more than enough time for them to exit */
 811                 msleep(125);
 812         }
 813
 814         if (!list_empty(&server->pending_mid_q)) {
 815                 /*
 816                  * mpx threads have not exited yet give them at least the smb
 817                  * send timeout time for long ops.
 818                  *
 819                  * Due to delays on oplock break requests, we need to wait at
 820                  * least 45 seconds before giving up on a request getting a
 821                  * response and going ahead and killing cifsd.
 822                  */
 823                 cifs_dbg(FYI, "Wait for exit from demultiplex thread\n");
 824                 msleep(46000);
 825                 /*
 826                  * If threads still have not exited they are probably never
 827                  * coming home not much else we can do but free the memory.
 828                  */
 829         }
 830
 831         kfree(server);
 832
 833         length = atomic_dec_return(&tcpSesAllocCount);
 834         if (length > 0)
 835                 mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
 836 }
 837
 838 static int
 839 standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 840 {
 841         int length;
 842         char *buf = server->smallbuf;
 843         unsigned int pdu_length = server->pdu_size;
 844
 845         /* make sure this will fit in a large buffer */
 846         if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
 847                 server->vals->header_preamble_size) {
 848                 cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
 849                 cifs_reconnect(server);
 850                 return -ECONNABORTED;
 851         }
 852
 853         /* switch to large buffer if too big for a small one */
 854         if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
 855                 server->large_buf = true;
 856                 memcpy(server->bigbuf, buf, server->total_read);
 857                 buf = server->bigbuf;
 858         }
 859
 860         /* now read the rest */
 861         length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
 862                                        pdu_length - HEADER_SIZE(server) + 1
 863                                        + server->vals->header_preamble_size);
 864
 865         if (length < 0)
 866                 return length;
 867         server->total_read += length;
 868
 869         dump_smb(buf, server->total_read);
 870
 871         return cifs_handle_standard(server, mid);
 872 }
 873
 874 int
 875 cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 876 {
 877         char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
 878         int length;
 879
 880         /*
 881          * We know that we received enough to get to the MID as we
 882          * checked the pdu_length earlier. Now check to see
 883          * if the rest of the header is OK. We borrow the length
 884          * var for the rest of the loop to avoid a new stack var.
 885          *
 886          * 48 bytes is enough to display the header and a little bit
 887          * into the payload for debugging purposes.
 888          */
 889         length = server->ops->check_message(buf, server->total_read, server);
 890         if (length != 0)
 891                 cifs_dump_mem("Bad SMB: ", buf,
 892                         min_t(unsigned int, server->total_read, 48));
 893
 894         if (server->ops->is_session_expired &&
 895             server->ops->is_session_expired(buf)) {
 896                 cifs_reconnect(server);
 897                 return -1;
 898         }
 899
 900         if (server->ops->is_status_pending &&
 901             server->ops->is_status_pending(buf, server))
 902                 return -1;
 903
 904         if (!mid)
 905                 return length;
 906
 907         handle_mid(mid, server, buf, length);
 908         return 0;
 909 }
 910
 911 static void
 912 smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
 913 {
 914         struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
 915         int scredits, in_flight;
 916
 917         /*
 918          * SMB1 does not use credits.
 919          */
 920         if (server->vals->header_preamble_size)
 921                 return;
 922
 923         if (shdr->CreditRequest) {
 924                 spin_lock(&server->req_lock);
 925                 server->credits += le16_to_cpu(shdr->CreditRequest);
 926                 scredits = server->credits;
 927                 in_flight = server->in_flight;
 928                 spin_unlock(&server->req_lock);
 929                 wake_up(&server->request_q);
 930
 931                 trace_smb3_add_credits(server->CurrentMid,
 932                                 server->conn_id, server->hostname, scredits,
 933                                 le16_to_cpu(shdr->CreditRequest), in_flight);
 934                 cifs_server_dbg(FYI, "%s: added %u credits total=%d\n",
 935                                 __func__, le16_to_cpu(shdr->CreditRequest),
 936                                 scredits);
 937         }
 938 }
 939
 940
 941 static int
 942 cifs_demultiplex_thread(void *p)
 943 {
 944         int i, num_mids, length;
 945         struct TCP_Server_Info *server = p;
 946         unsigned int pdu_length;
 947         unsigned int next_offset;
 948         char *buf = NULL;
 949         struct task_struct *task_to_wake = NULL;
 950         struct mid_q_entry *mids[MAX_COMPOUND];
 951         char *bufs[MAX_COMPOUND];
 952         unsigned int noreclaim_flag, num_io_timeout = 0;
 953
 954         noreclaim_flag = memalloc_noreclaim_save();
 955         cifs_dbg(FYI, "Demultiplex PID: %d\n", task_pid_nr(current));
 956
 957         length = atomic_inc_return(&tcpSesAllocCount);
 958         if (length > 1)
 959                 mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
 960
 961         set_freezable();
 962         allow_kernel_signal(SIGKILL);
 963         while (server->tcpStatus != CifsExiting) {
 964                 if (try_to_freeze())
 965                         continue;
 966
 967                 if (!allocate_buffers(server))
 968                         continue;
 969
 970                 server->large_buf = false;
 971                 buf = server->smallbuf;
 972                 pdu_length = 4; /* enough to get RFC1001 header */
 973
 974                 length = cifs_read_from_socket(server, buf, pdu_length);
 975                 if (length < 0)
 976                         continue;
 977
 978                 if (server->vals->header_preamble_size == 0)
 979                         server->total_read = 0;
 980                 else
 981                         server->total_read = length;
 982
 983                 /*
 984                  * The right amount was read from socket - 4 bytes,
 985                  * so we can now interpret the length field.
 986                  */
 987                 pdu_length = get_rfc1002_length(buf);
 988
 989                 cifs_dbg(FYI, "RFC1002 header 0x%x\n", pdu_length);
 990                 if (!is_smb_response(server, buf[0]))
 991                         continue;
 992 next_pdu:
 993                 server->pdu_size = pdu_length;
 994
 995                 /* make sure we have enough to get to the MID */
 996                 if (server->pdu_size < HEADER_SIZE(server) - 1 -
 997                     server->vals->header_preamble_size) {
 998                         cifs_server_dbg(VFS, "SMB response too short (%u bytes)\n",
 999                                  server->pdu_size);
1000                         cifs_reconnect(server);
1001                         continue;
1002                 }
1003
1004                 /* read down to the MID */
1005                 length = cifs_read_from_socket(server,
1006                              buf + server->vals->header_preamble_size,
1007                              HEADER_SIZE(server) - 1
1008                              - server->vals->header_preamble_size);
1009                 if (length < 0)
1010                         continue;
1011                 server->total_read += length;
1012
1013                 if (server->ops->next_header) {
1014                         next_offset = server->ops->next_header(buf);
1015                         if (next_offset)
1016                                 server->pdu_size = next_offset;
1017                 }
1018
1019                 memset(mids, 0, sizeof(mids));
1020                 memset(bufs, 0, sizeof(bufs));
1021                 num_mids = 0;
1022
1023                 if (server->ops->is_transform_hdr &&
1024                     server->ops->receive_transform &&
1025                     server->ops->is_transform_hdr(buf)) {
1026                         length = server->ops->receive_transform(server,
1027                                                                 mids,
1028                                                                 bufs,
1029                                                                 &num_mids);
1030                 } else {
1031                         mids[0] = server->ops->find_mid(server, buf);
1032                         bufs[0] = buf;
1033                         num_mids = 1;
1034
1035                         if (!mids[0] || !mids[0]->receive)
1036                                 length = standard_receive3(server, mids[0]);
1037                         else
1038                                 length = mids[0]->receive(server, mids[0]);
1039                 }
1040
1041                 if (length < 0) {
1042                         for (i = 0; i < num_mids; i++)
1043                                 if (mids[i])
1044                                         cifs_mid_q_entry_release(mids[i]);
1045                         continue;
1046                 }
1047
1048                 if (server->ops->is_status_io_timeout &&
1049                     server->ops->is_status_io_timeout(buf)) {
1050                         num_io_timeout++;
1051                         if (num_io_timeout > NUM_STATUS_IO_TIMEOUT) {
1052                                 cifs_reconnect(server);
1053                                 num_io_timeout = 0;
1054                                 continue;
1055                         }
1056                 }
1057
1058                 server->lstrp = jiffies;
1059
1060                 for (i = 0; i < num_mids; i++) {
1061                         if (mids[i] != NULL) {
1062                                 mids[i]->resp_buf_size = server->pdu_size;
1063
1064                                 if (bufs[i] && server->ops->is_network_name_deleted)
1065                                         server->ops->is_network_name_deleted(bufs[i],
1066                                                                         server);
1067
1068                                 if (!mids[i]->multiRsp || mids[i]->multiEnd)
1069                                         mids[i]->callback(mids[i]);
1070
1071                                 cifs_mid_q_entry_release(mids[i]);
1072                         } else if (server->ops->is_oplock_break &&
1073                                    server->ops->is_oplock_break(bufs[i],
1074                                                                 server)) {
1075                                 smb2_add_credits_from_hdr(bufs[i], server);
1076                                 cifs_dbg(FYI, "Received oplock break\n");
1077                         } else {
1078                                 cifs_server_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n",
1079                                                 atomic_read(&midCount));
1080                                 cifs_dump_mem("Received Data is: ", bufs[i],
1081                                               HEADER_SIZE(server));
1082                                 smb2_add_credits_from_hdr(bufs[i], server);
1083 #ifdef CONFIG_CIFS_DEBUG2
1084                                 if (server->ops->dump_detail)
1085                                         server->ops->dump_detail(bufs[i],
1086                                                                  server);
1087                                 cifs_dump_mids(server);
1088 #endif /* CIFS_DEBUG2 */
1089                         }
1090                 }
1091
1092                 if (pdu_length > server->pdu_size) {
1093                         if (!allocate_buffers(server))
1094                                 continue;
1095                         pdu_length -= server->pdu_size;
1096                         server->total_read = 0;
1097                         server->large_buf = false;
1098                         buf = server->smallbuf;
1099                         goto next_pdu;
1100                 }
1101         } /* end while !EXITING */
1102
1103         /* buffer usually freed in free_mid - need to free it here on exit */
1104         cifs_buf_release(server->bigbuf);
1105         if (server->smallbuf) /* no sense logging a debug message if NULL */
1106                 cifs_small_buf_release(server->smallbuf);
1107
1108         task_to_wake = xchg(&server->tsk, NULL);
1109         clean_demultiplex_info(server);
1110
1111         /* if server->tsk was NULL then wait for a signal before exiting */
1112         if (!task_to_wake) {
1113                 set_current_state(TASK_INTERRUPTIBLE);
1114                 while (!signal_pending(current)) {
1115                         schedule();
1116                         set_current_state(TASK_INTERRUPTIBLE);
1117                 }
1118                 set_current_state(TASK_RUNNING);
1119         }
1120
1121         memalloc_noreclaim_restore(noreclaim_flag);
1122         module_put_and_exit(0);
1123 }
1124
1125 /*
1126  * Returns true if srcaddr isn't specified and rhs isn't specified, or
1127  * if srcaddr is specified and matches the IP address of the rhs argument
1128  */
1129 bool
1130 cifs_match_ipaddr(struct sockaddr *srcaddr, struct sockaddr *rhs)
1131 {
1132         switch (srcaddr->sa_family) {
1133         case AF_UNSPEC:
1134                 return (rhs->sa_family == AF_UNSPEC);
1135         case AF_INET: {
1136                 struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
1137                 struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
1138                 return (saddr4->sin_addr.s_addr == vaddr4->sin_addr.s_addr);
1139         }
1140         case AF_INET6: {
1141                 struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
1142                 struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
1143                 return ipv6_addr_equal(&saddr6->sin6_addr, &vaddr6->sin6_addr);
1144         }
1145         default:
1146                 WARN_ON(1);
1147                 return false; /* don't expect to be here */
1148         }
1149 }
1150
1151 /*
1152  * If no port is specified in addr structure, we try to match with 445 port
1153  * and if it fails - with 139 ports. It should be called only if address
1154  * families of server and addr are equal.
1155  */
1156 static bool
1157 match_port(struct TCP_Server_Info *server, struct sockaddr *addr)
1158 {
1159         __be16 port, *sport;
1160
1161         /* SMBDirect manages its own ports, don't match it here */
1162         if (server->rdma)
1163                 return true;
1164
1165         switch (addr->sa_family) {
1166         case AF_INET:
1167                 sport = &((struct sockaddr_in *) &server->dstaddr)->sin_port;
1168                 port = ((struct sockaddr_in *) addr)->sin_port;
1169                 break;
1170         case AF_INET6:
1171                 sport = &((struct sockaddr_in6 *) &server->dstaddr)->sin6_port;
1172                 port = ((struct sockaddr_in6 *) addr)->sin6_port;
1173                 break;
1174         default:
1175                 WARN_ON(1);
1176                 return false;
1177         }
1178
1179         if (!port) {
1180                 port = htons(CIFS_PORT);
1181                 if (port == *sport)
1182                         return true;
1183
1184                 port = htons(RFC1001_PORT);
1185         }
1186
1187         return port == *sport;
1188 }
1189
1190 static bool
1191 match_address(struct TCP_Server_Info *server, struct sockaddr *addr,
1192               struct sockaddr *srcaddr)
1193 {
1194         switch (addr->sa_family) {
1195         case AF_INET: {
1196                 struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
1197                 struct sockaddr_in *srv_addr4 =
1198                                         (struct sockaddr_in *)&server->dstaddr;
1199
1200                 if (addr4->sin_addr.s_addr != srv_addr4->sin_addr.s_addr)
1201                         return false;
1202                 break;
1203         }
1204         case AF_INET6: {
1205                 struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
1206                 struct sockaddr_in6 *srv_addr6 =
1207                                         (struct sockaddr_in6 *)&server->dstaddr;
1208
1209                 if (!ipv6_addr_equal(&addr6->sin6_addr,
1210                                      &srv_addr6->sin6_addr))
1211                         return false;
1212                 if (addr6->sin6_scope_id != srv_addr6->sin6_scope_id)
1213                         return false;
1214                 break;
1215         }
1216         default:
1217                 WARN_ON(1);
1218                 return false; /* don't expect to be here */
1219         }
1220
1221         if (!cifs_match_ipaddr(srcaddr, (struct sockaddr *)&server->srcaddr))
1222                 return false;
1223
1224         return true;
1225 }
1226
1227 static bool
1228 match_security(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1229 {
1230         /*
1231          * The select_sectype function should either return the ctx->sectype
1232          * that was specified, or "Unspecified" if that sectype was not
1233          * compatible with the given NEGOTIATE request.
1234          */
1235         if (server->ops->select_sectype(server, ctx->sectype)
1236              == Unspecified)
1237                 return false;
1238
1239         /*
1240          * Now check if signing mode is acceptable. No need to check
1241          * global_secflags at this point since if MUST_SIGN is set then
1242          * the server->sign had better be too.
1243          */
1244         if (ctx->sign && !server->sign)
1245                 return false;
1246
1247         return true;
1248 }
1249
1250 static int match_server(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1251 {
1252         struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
1253
1254         if (ctx->nosharesock) {
1255                 server->nosharesock = true;
1256                 return 0;
1257         }
1258
1259         /* this server does not share socket */
1260         if (server->nosharesock)
1261                 return 0;
1262
1263         /* If multidialect negotiation see if existing sessions match one */
1264         if (strcmp(ctx->vals->version_string, SMB3ANY_VERSION_STRING) == 0) {
1265                 if (server->vals->protocol_id < SMB30_PROT_ID)
1266                         return 0;
1267         } else if (strcmp(ctx->vals->version_string,
1268                    SMBDEFAULT_VERSION_STRING) == 0) {
1269                 if (server->vals->protocol_id < SMB21_PROT_ID)
1270                         return 0;
1271         } else if ((server->vals != ctx->vals) || (server->ops != ctx->ops))
1272                 return 0;
1273
1274         if (!net_eq(cifs_net_ns(server), current->nsproxy->net_ns))
1275                 return 0;
1276
1277         if (strcasecmp(server->hostname, ctx->server_hostname))
1278                 return 0;
1279
1280         if (!match_address(server, addr,
1281                            (struct sockaddr *)&ctx->srcaddr))
1282                 return 0;
1283
1284         if (!match_port(server, addr))
1285                 return 0;
1286
1287         if (!match_security(server, ctx))
1288                 return 0;
1289
1290         if (server->echo_interval != ctx->echo_interval * HZ)
1291                 return 0;
1292
1293         if (server->rdma != ctx->rdma)
1294                 return 0;
1295
1296         if (server->ignore_signature != ctx->ignore_signature)
1297                 return 0;
1298
1299         if (server->min_offload != ctx->min_offload)
1300                 return 0;
1301
1302         return 1;
1303 }
1304
1305 struct TCP_Server_Info *
1306 cifs_find_tcp_session(struct smb3_fs_context *ctx)
1307 {
1308         struct TCP_Server_Info *server;
1309
1310         spin_lock(&cifs_tcp_ses_lock);
1311         list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
1312 #ifdef CONFIG_CIFS_DFS_UPCALL
1313                 /*
1314                  * DFS failover implementation in cifs_reconnect() requires unique tcp sessions for
1315                  * DFS connections to do failover properly, so avoid sharing them with regular
1316                  * shares or even links that may connect to same server but having completely
1317                  * different failover targets.
1318                  */
1319                 if (server->is_dfs_conn)
1320                         continue;
1321 #endif
1322                 /*
1323                  * Skip ses channels since they're only handled in lower layers
1324                  * (e.g. cifs_send_recv).
1325                  */
1326                 if (server->is_channel || !match_server(server, ctx))
1327                         continue;
1328
1329                 ++server->srv_count;
1330                 spin_unlock(&cifs_tcp_ses_lock);
1331                 cifs_dbg(FYI, "Existing tcp session with server found\n");
1332                 return server;
1333         }
1334         spin_unlock(&cifs_tcp_ses_lock);
1335         return NULL;
1336 }
1337
1338 void
1339 cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
1340 {
1341         struct task_struct *task;
1342
1343         spin_lock(&cifs_tcp_ses_lock);
1344         if (--server->srv_count > 0) {
1345                 spin_unlock(&cifs_tcp_ses_lock);
1346                 return;
1347         }
1348
1349         /* srv_count can never go negative */
1350         WARN_ON(server->srv_count < 0);
1351
1352         put_net(cifs_net_ns(server));
1353
1354         list_del_init(&server->tcp_ses_list);
1355         spin_unlock(&cifs_tcp_ses_lock);
1356
1357         cancel_delayed_work_sync(&server->echo);
1358         cancel_delayed_work_sync(&server->resolve);
1359
1360         if (from_reconnect)
1361                 /*
1362                  * Avoid deadlock here: reconnect work calls
1363                  * cifs_put_tcp_session() at its end. Need to be sure
1364                  * that reconnect work does nothing with server pointer after
1365                  * that step.
1366                  */
1367                 cancel_delayed_work(&server->reconnect);
1368         else
1369                 cancel_delayed_work_sync(&server->reconnect);
1370
1371         spin_lock(&GlobalMid_Lock);
1372         server->tcpStatus = CifsExiting;
1373         spin_unlock(&GlobalMid_Lock);
1374
1375         cifs_crypto_secmech_release(server);
1376         cifs_fscache_release_client_cookie(server);
1377
1378         kfree(server->session_key.response);
1379         server->session_key.response = NULL;
1380         server->session_key.len = 0;
1381         kfree(server->hostname);
1382
1383         task = xchg(&server->tsk, NULL);
1384         if (task)
1385                 send_sig(SIGKILL, task, 1);
1386 }
1387
1388 struct TCP_Server_Info *
1389 cifs_get_tcp_session(struct smb3_fs_context *ctx)
1390 {
1391         struct TCP_Server_Info *tcp_ses = NULL;
1392         int rc;
1393
1394         cifs_dbg(FYI, "UNC: %s\n", ctx->UNC);
1395
1396         /* see if we already have a matching tcp_ses */
1397         tcp_ses = cifs_find_tcp_session(ctx);
1398         if (tcp_ses)
1399                 return tcp_ses;
1400
1401         tcp_ses = kzalloc(sizeof(struct TCP_Server_Info), GFP_KERNEL);
1402         if (!tcp_ses) {
1403                 rc = -ENOMEM;
1404                 goto out_err;
1405         }
1406
1407         tcp_ses->hostname = kstrdup(ctx->server_hostname, GFP_KERNEL);
1408         if (!tcp_ses->hostname) {
1409                 rc = -ENOMEM;
1410                 goto out_err;
1411         }
1412
1413         tcp_ses->ops = ctx->ops;
1414         tcp_ses->vals = ctx->vals;
1415         cifs_set_net_ns(tcp_ses, get_net(current->nsproxy->net_ns));
1416
1417         tcp_ses->conn_id = atomic_inc_return(&tcpSesNextId);
1418         tcp_ses->noblockcnt = ctx->rootfs;
1419         tcp_ses->noblocksnd = ctx->noblocksnd || ctx->rootfs;
1420         tcp_ses->noautotune = ctx->noautotune;
1421         tcp_ses->tcp_nodelay = ctx->sockopt_tcp_nodelay;
1422         tcp_ses->rdma = ctx->rdma;
1423         tcp_ses->in_flight = 0;
1424         tcp_ses->max_in_flight = 0;
1425         tcp_ses->credits = 1;
1426         init_waitqueue_head(&tcp_ses->response_q);
1427         init_waitqueue_head(&tcp_ses->request_q);
1428         INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
1429         mutex_init(&tcp_ses->srv_mutex);
1430         memcpy(tcp_ses->workstation_RFC1001_name,
1431                 ctx->source_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1432         memcpy(tcp_ses->server_RFC1001_name,
1433                 ctx->target_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1434         tcp_ses->session_estab = false;
1435         tcp_ses->sequence_number = 0;
1436         tcp_ses->reconnect_instance = 1;
1437         tcp_ses->lstrp = jiffies;
1438         tcp_ses->compress_algorithm = cpu_to_le16(ctx->compression);
1439         spin_lock_init(&tcp_ses->req_lock);
1440         INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
1441         INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
1442         INIT_DELAYED_WORK(&tcp_ses->echo, cifs_echo_request);
1443         INIT_DELAYED_WORK(&tcp_ses->resolve, cifs_resolve_server);
1444         INIT_DELAYED_WORK(&tcp_ses->reconnect, smb2_reconnect_server);
1445         mutex_init(&tcp_ses->reconnect_mutex);
1446         memcpy(&tcp_ses->srcaddr, &ctx->srcaddr,
1447                sizeof(tcp_ses->srcaddr));
1448         memcpy(&tcp_ses->dstaddr, &ctx->dstaddr,
1449                 sizeof(tcp_ses->dstaddr));
1450         if (ctx->use_client_guid)
1451                 memcpy(tcp_ses->client_guid, ctx->client_guid,
1452                        SMB2_CLIENT_GUID_SIZE);
1453         else
1454                 generate_random_uuid(tcp_ses->client_guid);
1455         /*
1456          * at this point we are the only ones with the pointer
1457          * to the struct since the kernel thread not created yet
1458          * no need to spinlock this init of tcpStatus or srv_count
1459          */
1460         tcp_ses->tcpStatus = CifsNew;
1461         ++tcp_ses->srv_count;
1462
1463         if (ctx->echo_interval >= SMB_ECHO_INTERVAL_MIN &&
1464                 ctx->echo_interval <= SMB_ECHO_INTERVAL_MAX)
1465                 tcp_ses->echo_interval = ctx->echo_interval * HZ;
1466         else
1467                 tcp_ses->echo_interval = SMB_ECHO_INTERVAL_DEFAULT * HZ;
1468         if (tcp_ses->rdma) {
1469 #ifndef CONFIG_CIFS_SMB_DIRECT
1470                 cifs_dbg(VFS, "CONFIG_CIFS_SMB_DIRECT is not enabled\n");
1471                 rc = -ENOENT;
1472                 goto out_err_crypto_release;
1473 #endif
1474                 tcp_ses->smbd_conn = smbd_get_connection(
1475                         tcp_ses, (struct sockaddr *)&ctx->dstaddr);
1476                 if (tcp_ses->smbd_conn) {
1477                         cifs_dbg(VFS, "RDMA transport established\n");
1478                         rc = 0;
1479                         goto smbd_connected;
1480                 } else {
1481                         rc = -ENOENT;
1482                         goto out_err_crypto_release;
1483                 }
1484         }
1485         rc = ip_connect(tcp_ses);
1486         if (rc < 0) {
1487                 cifs_dbg(VFS, "Error connecting to socket. Aborting operation.\n");
1488                 goto out_err_crypto_release;
1489         }
1490 smbd_connected:
1491         /*
1492          * since we're in a cifs function already, we know that
1493          * this will succeed. No need for try_module_get().
1494          */
1495         __module_get(THIS_MODULE);
1496         tcp_ses->tsk = kthread_run(cifs_demultiplex_thread,
1497                                   tcp_ses, "cifsd");
1498         if (IS_ERR(tcp_ses->tsk)) {
1499                 rc = PTR_ERR(tcp_ses->tsk);
1500                 cifs_dbg(VFS, "error %d create cifsd thread\n", rc);
1501                 module_put(THIS_MODULE);
1502                 goto out_err_crypto_release;
1503         }
1504         tcp_ses->min_offload = ctx->min_offload;
1505         /*
1506          * at this point we are the only ones with the pointer
1507          * to the struct since the kernel thread not created yet
1508          * no need to spinlock this update of tcpStatus
1509          */
1510         tcp_ses->tcpStatus = CifsNeedNegotiate;
1511
1512         if ((ctx->max_credits < 20) || (ctx->max_credits > 60000))
1513                 tcp_ses->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
1514         else
1515                 tcp_ses->max_credits = ctx->max_credits;
1516
1517         tcp_ses->nr_targets = 1;
1518         tcp_ses->ignore_signature = ctx->ignore_signature;
1519         /* thread spawned, put it on the list */
1520         spin_lock(&cifs_tcp_ses_lock);
1521         list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
1522         spin_unlock(&cifs_tcp_ses_lock);
1523
1524         cifs_fscache_get_client_cookie(tcp_ses);
1525
1526         /* queue echo request delayed work */
1527         queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
1528
1529         /* queue dns resolution delayed work */
1530         cifs_dbg(FYI, "%s: next dns resolution scheduled for %d seconds in the future\n",
1531                  __func__, SMB_DNS_RESOLVE_INTERVAL_DEFAULT);
1532
1533         queue_delayed_work(cifsiod_wq, &tcp_ses->resolve, (SMB_DNS_RESOLVE_INTERVAL_DEFAULT * HZ));
1534
1535         return tcp_ses;
1536
1537 out_err_crypto_release:
1538         cifs_crypto_secmech_release(tcp_ses);
1539
1540         put_net(cifs_net_ns(tcp_ses));
1541
1542 out_err:
1543         if (tcp_ses) {
1544                 kfree(tcp_ses->hostname);
1545                 if (tcp_ses->ssocket)
1546                         sock_release(tcp_ses->ssocket);
1547                 kfree(tcp_ses);
1548         }
1549         return ERR_PTR(rc);
1550 }
1551
1552 static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1553 {
1554         if (ctx->sectype != Unspecified &&
1555             ctx->sectype != ses->sectype)
1556                 return 0;
1557
1558         /*
1559          * If an existing session is limited to less channels than
1560          * requested, it should not be reused
1561          */
1562         if (ses->chan_max < ctx->max_channels)
1563                 return 0;
1564
1565         switch (ses->sectype) {
1566         case Kerberos:
1567                 if (!uid_eq(ctx->cred_uid, ses->cred_uid))
1568                         return 0;
1569                 break;
1570         default:
1571                 /* NULL username means anonymous session */
1572                 if (ses->user_name == NULL) {
1573                         if (!ctx->nullauth)
1574                                 return 0;
1575                         break;
1576                 }
1577
1578                 /* anything else takes username/password */
1579                 if (strncmp(ses->user_name,
1580                             ctx->username ? ctx->username : "",
1581                             CIFS_MAX_USERNAME_LEN))
1582                         return 0;
1583                 if ((ctx->username && strlen(ctx->username) != 0) &&
1584                     ses->password != NULL &&
1585                     strncmp(ses->password,
1586                             ctx->password ? ctx->password : "",
1587                             CIFS_MAX_PASSWORD_LEN))
1588                         return 0;
1589         }
1590         return 1;
1591 }
1592
1593 /**
1594  * cifs_setup_ipc - helper to setup the IPC tcon for the session
1595  * @ses: smb session to issue the request on
1596  * @ctx: the superblock configuration context to use for building the
1597  *       new tree connection for the IPC (interprocess communication RPC)
1598  *
1599  * A new IPC connection is made and stored in the session
1600  * tcon_ipc. The IPC tcon has the same lifetime as the session.
1601  */
1602 static int
1603 cifs_setup_ipc(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1604 {
1605         int rc = 0, xid;
1606         struct cifs_tcon *tcon;
1607         char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0};
1608         bool seal = false;
1609         struct TCP_Server_Info *server = ses->server;
1610
1611         /*
1612          * If the mount request that resulted in the creation of the
1613          * session requires encryption, force IPC to be encrypted too.
1614          */
1615         if (ctx->seal) {
1616                 if (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)
1617                         seal = true;
1618                 else {
1619                         cifs_server_dbg(VFS,
1620                                  "IPC: server doesn't support encryption\n");
1621                         return -EOPNOTSUPP;
1622                 }
1623         }
1624
1625         tcon = tconInfoAlloc();
1626         if (tcon == NULL)
1627                 return -ENOMEM;
1628
1629         scnprintf(unc, sizeof(unc), "\\\\%s\\IPC$", server->hostname);
1630
1631         xid = get_xid();
1632         tcon->ses = ses;
1633         tcon->ipc = true;
1634         tcon->seal = seal;
1635         rc = server->ops->tree_connect(xid, ses, unc, tcon, ctx->local_nls);
1636         free_xid(xid);
1637
1638         if (rc) {
1639                 cifs_server_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
1640                 tconInfoFree(tcon);
1641                 goto out;
1642         }
1643
1644         cifs_dbg(FYI, "IPC tcon rc = %d ipc tid = %d\n", rc, tcon->tid);
1645
1646         ses->tcon_ipc = tcon;
1647 out:
1648         return rc;
1649 }
1650
1651 /**
1652  * cifs_free_ipc - helper to release the session IPC tcon
1653  * @ses: smb session to unmount the IPC from
1654  *
1655  * Needs to be called everytime a session is destroyed.
1656  *
1657  * On session close, the IPC is closed and the server must release all tcons of the session.
1658  * No need to send a tree disconnect here.
1659  *
1660  * Besides, it will make the server to not close durable and resilient files on session close, as
1661  * specified in MS-SMB2 3.3.5.6 Receiving an SMB2 LOGOFF Request.
1662  */
1663 static int
1664 cifs_free_ipc(struct cifs_ses *ses)
1665 {
1666         struct cifs_tcon *tcon = ses->tcon_ipc;
1667
1668         if (tcon == NULL)
1669                 return 0;
1670
1671         tconInfoFree(tcon);
1672         ses->tcon_ipc = NULL;
1673         return 0;
1674 }
1675
1676 static struct cifs_ses *
1677 cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1678 {
1679         struct cifs_ses *ses;
1680
1681         spin_lock(&cifs_tcp_ses_lock);
1682         list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
1683                 if (ses->status == CifsExiting)
1684                         continue;
1685                 if (!match_session(ses, ctx))
1686                         continue;
1687                 ++ses->ses_count;
1688                 spin_unlock(&cifs_tcp_ses_lock);
1689                 return ses;
1690         }
1691         spin_unlock(&cifs_tcp_ses_lock);
1692         return NULL;
1693 }
1694
1695 void cifs_put_smb_ses(struct cifs_ses *ses)
1696 {
1697         unsigned int rc, xid;
1698         struct TCP_Server_Info *server = ses->server;
1699         cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
1700
1701         spin_lock(&cifs_tcp_ses_lock);
1702         if (ses->status == CifsExiting) {
1703                 spin_unlock(&cifs_tcp_ses_lock);
1704                 return;
1705         }
1706
1707         cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
1708         cifs_dbg(FYI, "%s: ses ipc: %s\n", __func__, ses->tcon_ipc ? ses->tcon_ipc->treeName : "NONE");
1709
1710         if (--ses->ses_count > 0) {
1711                 spin_unlock(&cifs_tcp_ses_lock);
1712                 return;
1713         }
1714         spin_unlock(&cifs_tcp_ses_lock);
1715
1716         /* ses_count can never go negative */
1717         WARN_ON(ses->ses_count < 0);
1718
1719         spin_lock(&GlobalMid_Lock);
1720         if (ses->status == CifsGood)
1721                 ses->status = CifsExiting;
1722         spin_unlock(&GlobalMid_Lock);
1723
1724         cifs_free_ipc(ses);
1725
1726         if (ses->status == CifsExiting && server->ops->logoff) {
1727                 xid = get_xid();
1728                 rc = server->ops->logoff(xid, ses);
1729                 if (rc)
1730                         cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
1731                                 __func__, rc);
1732                 _free_xid(xid);
1733         }
1734
1735         spin_lock(&cifs_tcp_ses_lock);
1736         list_del_init(&ses->smb_ses_list);
1737         spin_unlock(&cifs_tcp_ses_lock);
1738
1739         /* close any extra channels */
1740         if (ses->chan_count > 1) {
1741                 int i;
1742
1743                 for (i = 1; i < ses->chan_count; i++)
1744                         cifs_put_tcp_session(ses->chans[i].server, 0);
1745         }
1746
1747         sesInfoFree(ses);
1748         cifs_put_tcp_session(server, 0);
1749 }
1750
1751 #ifdef CONFIG_KEYS
1752
1753 /* strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1 */
1754 #define CIFSCREDS_DESC_SIZE (7 + CIFS_MAX_DOMAINNAME_LEN + 1)
1755
1756 /* Populate username and pw fields from keyring if possible */
1757 static int
1758 cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
1759 {
1760         int rc = 0;
1761         int is_domain = 0;
1762         const char *delim, *payload;
1763         char *desc;
1764         ssize_t len;
1765         struct key *key;
1766         struct TCP_Server_Info *server = ses->server;
1767         struct sockaddr_in *sa;
1768         struct sockaddr_in6 *sa6;
1769         const struct user_key_payload *upayload;
1770
1771         desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
1772         if (!desc)
1773                 return -ENOMEM;
1774
1775         /* try to find an address key first */
1776         switch (server->dstaddr.ss_family) {
1777         case AF_INET:
1778                 sa = (struct sockaddr_in *)&server->dstaddr;
1779                 sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
1780                 break;
1781         case AF_INET6:
1782                 sa6 = (struct sockaddr_in6 *)&server->dstaddr;
1783                 sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
1784                 break;
1785         default:
1786                 cifs_dbg(FYI, "Bad ss_family (%hu)\n",
1787                          server->dstaddr.ss_family);
1788                 rc = -EINVAL;
1789                 goto out_err;
1790         }
1791
1792         cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
1793         key = request_key(&key_type_logon, desc, "");
1794         if (IS_ERR(key)) {
1795                 if (!ses->domainName) {
1796                         cifs_dbg(FYI, "domainName is NULL\n");
1797                         rc = PTR_ERR(key);
1798                         goto out_err;
1799                 }
1800
1801                 /* didn't work, try to find a domain key */
1802                 sprintf(desc, "cifs:d:%s", ses->domainName);
1803                 cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
1804                 key = request_key(&key_type_logon, desc, "");
1805                 if (IS_ERR(key)) {
1806                         rc = PTR_ERR(key);
1807                         goto out_err;
1808                 }
1809                 is_domain = 1;
1810         }
1811
1812         down_read(&key->sem);
1813         upayload = user_key_payload_locked(key);
1814         if (IS_ERR_OR_NULL(upayload)) {
1815                 rc = upayload ? PTR_ERR(upayload) : -EINVAL;
1816                 goto out_key_put;
1817         }
1818
1819         /* find first : in payload */
1820         payload = upayload->data;
1821         delim = strnchr(payload, upayload->datalen, ':');
1822         cifs_dbg(FYI, "payload=%s\n", payload);
1823         if (!delim) {
1824                 cifs_dbg(FYI, "Unable to find ':' in payload (datalen=%d)\n",
1825                          upayload->datalen);
1826                 rc = -EINVAL;
1827                 goto out_key_put;
1828         }
1829
1830         len = delim - payload;
1831         if (len > CIFS_MAX_USERNAME_LEN || len <= 0) {
1832                 cifs_dbg(FYI, "Bad value from username search (len=%zd)\n",
1833                          len);
1834                 rc = -EINVAL;
1835                 goto out_key_put;
1836         }
1837
1838         ctx->username = kstrndup(payload, len, GFP_KERNEL);
1839         if (!ctx->username) {
1840                 cifs_dbg(FYI, "Unable to allocate %zd bytes for username\n",
1841                          len);
1842                 rc = -ENOMEM;
1843                 goto out_key_put;
1844         }
1845         cifs_dbg(FYI, "%s: username=%s\n", __func__, ctx->username);
1846
1847         len = key->datalen - (len + 1);
1848         if (len > CIFS_MAX_PASSWORD_LEN || len <= 0) {
1849                 cifs_dbg(FYI, "Bad len for password search (len=%zd)\n", len);
1850                 rc = -EINVAL;
1851                 kfree(ctx->username);
1852                 ctx->username = NULL;
1853                 goto out_key_put;
1854         }
1855
1856         ++delim;
1857         ctx->password = kstrndup(delim, len, GFP_KERNEL);
1858         if (!ctx->password) {
1859                 cifs_dbg(FYI, "Unable to allocate %zd bytes for password\n",
1860                          len);
1861                 rc = -ENOMEM;
1862                 kfree(ctx->username);
1863                 ctx->username = NULL;
1864                 goto out_key_put;
1865         }
1866
1867         /*
1868          * If we have a domain key then we must set the domainName in the
1869          * for the request.
1870          */
1871         if (is_domain && ses->domainName) {
1872                 ctx->domainname = kstrdup(ses->domainName, GFP_KERNEL);
1873                 if (!ctx->domainname) {
1874                         cifs_dbg(FYI, "Unable to allocate %zd bytes for domain\n",
1875                                  len);
1876                         rc = -ENOMEM;
1877                         kfree(ctx->username);
1878                         ctx->username = NULL;
1879                         kfree_sensitive(ctx->password);
1880                         ctx->password = NULL;
1881                         goto out_key_put;
1882                 }
1883         }
1884
1885 out_key_put:
1886         up_read(&key->sem);
1887         key_put(key);
1888 out_err:
1889         kfree(desc);
1890         cifs_dbg(FYI, "%s: returning %d\n", __func__, rc);
1891         return rc;
1892 }
1893 #else /* ! CONFIG_KEYS */
1894 static inline int
1895 cifs_set_cifscreds(struct smb3_fs_context *ctx __attribute__((unused)),
1896                    struct cifs_ses *ses __attribute__((unused)))
1897 {
1898         return -ENOSYS;
1899 }
1900 #endif /* CONFIG_KEYS */
1901
1902 /**
1903  * cifs_get_smb_ses - get a session matching @ctx data from @server
1904  * @server: server to setup the session to
1905  * @ctx: superblock configuration context to use to setup the session
1906  *
1907  * This function assumes it is being called from cifs_mount() where we
1908  * already got a server reference (server refcount +1). See
1909  * cifs_get_tcon() for refcount explanations.
1910  */
1911 struct cifs_ses *
1912 cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1913 {
1914         int rc = -ENOMEM;
1915         unsigned int xid;
1916         struct cifs_ses *ses;
1917         struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
1918         struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
1919
1920         xid = get_xid();
1921
1922         ses = cifs_find_smb_ses(server, ctx);
1923         if (ses) {
1924                 cifs_dbg(FYI, "Existing smb sess found (status=%d)\n",
1925                          ses->status);
1926
1927                 mutex_lock(&ses->session_mutex);
1928                 rc = cifs_negotiate_protocol(xid, ses);
1929                 if (rc) {
1930                         mutex_unlock(&ses->session_mutex);
1931                         /* problem -- put our ses reference */
1932                         cifs_put_smb_ses(ses);
1933                         free_xid(xid);
1934                         return ERR_PTR(rc);
1935                 }
1936                 if (ses->need_reconnect) {
1937                         cifs_dbg(FYI, "Session needs reconnect\n");
1938                         rc = cifs_setup_session(xid, ses,
1939                                                 ctx->local_nls);
1940                         if (rc) {
1941                                 mutex_unlock(&ses->session_mutex);
1942                                 /* problem -- put our reference */
1943                                 cifs_put_smb_ses(ses);
1944                                 free_xid(xid);
1945                                 return ERR_PTR(rc);
1946                         }
1947                 }
1948                 mutex_unlock(&ses->session_mutex);
1949
1950                 /* existing SMB ses has a server reference already */
1951                 cifs_put_tcp_session(server, 0);
1952                 free_xid(xid);
1953                 return ses;
1954         }
1955
1956         cifs_dbg(FYI, "Existing smb sess not found\n");
1957         ses = sesInfoAlloc();
1958         if (ses == NULL)
1959                 goto get_ses_fail;
1960
1961         /* new SMB session uses our server ref */
1962         ses->server = server;
1963         if (server->dstaddr.ss_family == AF_INET6)
1964                 sprintf(ses->ip_addr, "%pI6", &addr6->sin6_addr);
1965         else
1966                 sprintf(ses->ip_addr, "%pI4", &addr->sin_addr);
1967
1968         if (ctx->username) {
1969                 ses->user_name = kstrdup(ctx->username, GFP_KERNEL);
1970                 if (!ses->user_name)
1971                         goto get_ses_fail;
1972         }
1973
1974         /* ctx->password freed at unmount */
1975         if (ctx->password) {
1976                 ses->password = kstrdup(ctx->password, GFP_KERNEL);
1977                 if (!ses->password)
1978                         goto get_ses_fail;
1979         }
1980         if (ctx->domainname) {
1981                 ses->domainName = kstrdup(ctx->domainname, GFP_KERNEL);
1982                 if (!ses->domainName)
1983                         goto get_ses_fail;
1984         }
1985         if (ctx->workstation_name) {
1986                 ses->workstation_name = kstrdup(ctx->workstation_name,
1987                                                 GFP_KERNEL);
1988                 if (!ses->workstation_name)
1989                         goto get_ses_fail;
1990         }
1991         if (ctx->domainauto)
1992                 ses->domainAuto = ctx->domainauto;
1993         ses->cred_uid = ctx->cred_uid;
1994         ses->linux_uid = ctx->linux_uid;
1995
1996         ses->sectype = ctx->sectype;
1997         ses->sign = ctx->sign;
1998         mutex_lock(&ses->session_mutex);
1999
2000         /* add server as first channel */
2001         ses->chans[0].server = server;
2002         ses->chan_count = 1;
2003         ses->chan_max = ctx->multichannel ? ctx->max_channels:1;
2004
2005         rc = cifs_negotiate_protocol(xid, ses);
2006         if (!rc)
2007                 rc = cifs_setup_session(xid, ses, ctx->local_nls);
2008
2009         /* each channel uses a different signing key */
2010         memcpy(ses->chans[0].signkey, ses->smb3signingkey,
2011                sizeof(ses->smb3signingkey));
2012
2013         mutex_unlock(&ses->session_mutex);
2014         if (rc)
2015                 goto get_ses_fail;
2016
2017         /* success, put it on the list and add it as first channel */
2018         spin_lock(&cifs_tcp_ses_lock);
2019         list_add(&ses->smb_ses_list, &server->smb_ses_list);
2020         spin_unlock(&cifs_tcp_ses_lock);
2021
2022         free_xid(xid);
2023
2024         cifs_setup_ipc(ses, ctx);
2025
2026         return ses;
2027
2028 get_ses_fail:
2029         sesInfoFree(ses);
2030         free_xid(xid);
2031         return ERR_PTR(rc);
2032 }
2033
2034 static int match_tcon(struct cifs_tcon *tcon, struct smb3_fs_context *ctx)
2035 {
2036         if (tcon->tidStatus == CifsExiting)
2037                 return 0;
2038         if (strncmp(tcon->treeName, ctx->UNC, MAX_TREE_SIZE))
2039                 return 0;
2040         if (tcon->seal != ctx->seal)
2041                 return 0;
2042         if (tcon->snapshot_time != ctx->snapshot_time)
2043                 return 0;
2044         if (tcon->handle_timeout != ctx->handle_timeout)
2045                 return 0;
2046         if (tcon->no_lease != ctx->no_lease)
2047                 return 0;
2048         if (tcon->nodelete != ctx->nodelete)
2049                 return 0;
2050         return 1;
2051 }
2052
2053 static struct cifs_tcon *
2054 cifs_find_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2055 {
2056         struct list_head *tmp;
2057         struct cifs_tcon *tcon;
2058
2059         spin_lock(&cifs_tcp_ses_lock);
2060         list_for_each(tmp, &ses->tcon_list) {
2061                 tcon = list_entry(tmp, struct cifs_tcon, tcon_list);
2062
2063                 if (!match_tcon(tcon, ctx))
2064                         continue;
2065                 ++tcon->tc_count;
2066                 spin_unlock(&cifs_tcp_ses_lock);
2067                 return tcon;
2068         }
2069         spin_unlock(&cifs_tcp_ses_lock);
2070         return NULL;
2071 }
2072
2073 void
2074 cifs_put_tcon(struct cifs_tcon *tcon)
2075 {
2076         unsigned int xid;
2077         struct cifs_ses *ses;
2078
2079         /*
2080          * IPC tcon share the lifetime of their session and are
2081          * destroyed in the session put function
2082          */
2083         if (tcon == NULL || tcon->ipc)
2084                 return;
2085
2086         ses = tcon->ses;
2087         cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
2088         spin_lock(&cifs_tcp_ses_lock);
2089         if (--tcon->tc_count > 0) {
2090                 spin_unlock(&cifs_tcp_ses_lock);
2091                 return;
2092         }
2093
2094         /* tc_count can never go negative */
2095         WARN_ON(tcon->tc_count < 0);
2096
2097         if (tcon->use_witness) {
2098                 int rc;
2099
2100                 rc = cifs_swn_unregister(tcon);
2101                 if (rc < 0) {
2102                         cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
2103                                         __func__, rc);
2104                 }
2105         }
2106
2107         list_del_init(&tcon->tcon_list);
2108         spin_unlock(&cifs_tcp_ses_lock);
2109
2110         xid = get_xid();
2111         if (ses->server->ops->tree_disconnect)
2112                 ses->server->ops->tree_disconnect(xid, tcon);
2113         _free_xid(xid);
2114
2115         cifs_fscache_release_super_cookie(tcon);
2116         tconInfoFree(tcon);
2117         cifs_put_smb_ses(ses);
2118 }
2119
2120 /**
2121  * cifs_get_tcon - get a tcon matching @ctx data from @ses
2122  * @ses: smb session to issue the request on
2123  * @ctx: the superblock configuration context to use for building the
2124  *
2125  * - tcon refcount is the number of mount points using the tcon.
2126  * - ses refcount is the number of tcon using the session.
2127  *
2128  * 1. This function assumes it is being called from cifs_mount() where
2129  *    we already got a session reference (ses refcount +1).
2130  *
2131  * 2. Since we're in the context of adding a mount point, the end
2132  *    result should be either:
2133  *
2134  * a) a new tcon already allocated with refcount=1 (1 mount point) and
2135  *    its session refcount incremented (1 new tcon). This +1 was
2136  *    already done in (1).
2137  *
2138  * b) an existing tcon with refcount+1 (add a mount point to it) and
2139  *    identical ses refcount (no new tcon). Because of (1) we need to
2140  *    decrement the ses refcount.
2141  */
2142 static struct cifs_tcon *
2143 cifs_get_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2144 {
2145         int rc, xid;
2146         struct cifs_tcon *tcon;
2147
2148         tcon = cifs_find_tcon(ses, ctx);
2149         if (tcon) {
2150                 /*
2151                  * tcon has refcount already incremented but we need to
2152                  * decrement extra ses reference gotten by caller (case b)
2153                  */
2154                 cifs_dbg(FYI, "Found match on UNC path\n");
2155                 cifs_put_smb_ses(ses);
2156                 return tcon;
2157         }
2158
2159         if (!ses->server->ops->tree_connect) {
2160                 rc = -ENOSYS;
2161                 goto out_fail;
2162         }
2163
2164         tcon = tconInfoAlloc();
2165         if (tcon == NULL) {
2166                 rc = -ENOMEM;
2167                 goto out_fail;
2168         }
2169
2170         if (ctx->snapshot_time) {
2171                 if (ses->server->vals->protocol_id == 0) {
2172                         cifs_dbg(VFS,
2173                              "Use SMB2 or later for snapshot mount option\n");
2174                         rc = -EOPNOTSUPP;
2175                         goto out_fail;
2176                 } else
2177                         tcon->snapshot_time = ctx->snapshot_time;
2178         }
2179
2180         if (ctx->handle_timeout) {
2181                 if (ses->server->vals->protocol_id == 0) {
2182                         cifs_dbg(VFS,
2183                              "Use SMB2.1 or later for handle timeout option\n");
2184                         rc = -EOPNOTSUPP;
2185                         goto out_fail;
2186                 } else
2187                         tcon->handle_timeout = ctx->handle_timeout;
2188         }
2189
2190         tcon->ses = ses;
2191         if (ctx->password) {
2192                 tcon->password = kstrdup(ctx->password, GFP_KERNEL);
2193                 if (!tcon->password) {
2194                         rc = -ENOMEM;
2195                         goto out_fail;
2196                 }
2197         }
2198
2199         if (ctx->seal) {
2200                 if (ses->server->vals->protocol_id == 0) {
2201                         cifs_dbg(VFS,
2202                                  "SMB3 or later required for encryption\n");
2203                         rc = -EOPNOTSUPP;
2204                         goto out_fail;
2205                 } else if (tcon->ses->server->capabilities &
2206                                         SMB2_GLOBAL_CAP_ENCRYPTION)
2207                         tcon->seal = true;
2208                 else {
2209                         cifs_dbg(VFS, "Encryption is not supported on share\n");
2210                         rc = -EOPNOTSUPP;
2211                         goto out_fail;
2212                 }
2213         }
2214
2215         if (ctx->linux_ext) {
2216                 if (ses->server->posix_ext_supported) {
2217                         tcon->posix_extensions = true;
2218                         pr_warn_once("SMB3.11 POSIX Extensions are experimental\n");
2219                 } else {
2220                         cifs_dbg(VFS, "Server does not support mounting with posix SMB3.11 extensions\n");
2221                         rc = -EOPNOTSUPP;
2222                         goto out_fail;
2223                 }
2224         }
2225
2226         /*
2227          * BB Do we need to wrap session_mutex around this TCon call and Unix
2228          * SetFS as we do on SessSetup and reconnect?
2229          */
2230         xid = get_xid();
2231         rc = ses->server->ops->tree_connect(xid, ses, ctx->UNC, tcon,
2232                                             ctx->local_nls);
2233         free_xid(xid);
2234         cifs_dbg(FYI, "Tcon rc = %d\n", rc);
2235         if (rc)
2236                 goto out_fail;
2237
2238         tcon->use_persistent = false;
2239         /* check if SMB2 or later, CIFS does not support persistent handles */
2240         if (ctx->persistent) {
2241                 if (ses->server->vals->protocol_id == 0) {
2242                         cifs_dbg(VFS,
2243                              "SMB3 or later required for persistent handles\n");
2244                         rc = -EOPNOTSUPP;
2245                         goto out_fail;
2246                 } else if (ses->server->capabilities &
2247                            SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2248                         tcon->use_persistent = true;
2249                 else /* persistent handles requested but not supported */ {
2250                         cifs_dbg(VFS,
2251                                 "Persistent handles not supported on share\n");
2252                         rc = -EOPNOTSUPP;
2253                         goto out_fail;
2254                 }
2255         } else if ((tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
2256              && (ses->server->capabilities & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2257              && (ctx->nopersistent == false)) {
2258                 cifs_dbg(FYI, "enabling persistent handles\n");
2259                 tcon->use_persistent = true;
2260         } else if (ctx->resilient) {
2261                 if (ses->server->vals->protocol_id == 0) {
2262                         cifs_dbg(VFS,
2263                              "SMB2.1 or later required for resilient handles\n");
2264                         rc = -EOPNOTSUPP;
2265                         goto out_fail;
2266                 }
2267                 tcon->use_resilient = true;
2268         }
2269
2270         tcon->use_witness = false;
2271         if (IS_ENABLED(CONFIG_CIFS_SWN_UPCALL) && ctx->witness) {
2272                 if (ses->server->vals->protocol_id >= SMB30_PROT_ID) {
2273                         if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER) {
2274                                 /*
2275                                  * Set witness in use flag in first place
2276                                  * to retry registration in the echo task
2277                                  */
2278                                 tcon->use_witness = true;
2279                                 /* And try to register immediately */
2280                                 rc = cifs_swn_register(tcon);
2281                                 if (rc < 0) {
2282                                         cifs_dbg(VFS, "Failed to register for witness notifications: %d\n", rc);
2283                                         goto out_fail;
2284                                 }
2285                         } else {
2286                                 /* TODO: try to extend for non-cluster uses (eg multichannel) */
2287                                 cifs_dbg(VFS, "witness requested on mount but no CLUSTER capability on share\n");
2288                                 rc = -EOPNOTSUPP;
2289                                 goto out_fail;
2290                         }
2291                 } else {
2292                         cifs_dbg(VFS, "SMB3 or later required for witness option\n");
2293                         rc = -EOPNOTSUPP;
2294                         goto out_fail;
2295                 }
2296         }
2297
2298         /* If the user really knows what they are doing they can override */
2299         if (tcon->share_flags & SMB2_SHAREFLAG_NO_CACHING) {
2300                 if (ctx->cache_ro)
2301                         cifs_dbg(VFS, "cache=ro requested on mount but NO_CACHING flag set on share\n");
2302                 else if (ctx->cache_rw)
2303                         cifs_dbg(VFS, "cache=singleclient requested on mount but NO_CACHING flag set on share\n");
2304         }
2305
2306         if (ctx->no_lease) {
2307                 if (ses->server->vals->protocol_id == 0) {
2308                         cifs_dbg(VFS,
2309                                 "SMB2 or later required for nolease option\n");
2310                         rc = -EOPNOTSUPP;
2311                         goto out_fail;
2312                 } else
2313                         tcon->no_lease = ctx->no_lease;
2314         }
2315
2316         /*
2317          * We can have only one retry value for a connection to a share so for
2318          * resources mounted more than once to the same server share the last
2319          * value passed in for the retry flag is used.
2320          */
2321         tcon->retry = ctx->retry;
2322         tcon->nocase = ctx->nocase;
2323         if (ses->server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING)
2324                 tcon->nohandlecache = ctx->nohandlecache;
2325         else
2326                 tcon->nohandlecache = true;
2327         tcon->nodelete = ctx->nodelete;
2328         tcon->local_lease = ctx->local_lease;
2329         INIT_LIST_HEAD(&tcon->pending_opens);
2330
2331         spin_lock(&cifs_tcp_ses_lock);
2332         list_add(&tcon->tcon_list, &ses->tcon_list);
2333         spin_unlock(&cifs_tcp_ses_lock);
2334
2335         cifs_fscache_get_super_cookie(tcon);
2336
2337         return tcon;
2338
2339 out_fail:
2340         tconInfoFree(tcon);
2341         return ERR_PTR(rc);
2342 }
2343
2344 void
2345 cifs_put_tlink(struct tcon_link *tlink)
2346 {
2347         if (!tlink || IS_ERR(tlink))
2348                 return;
2349
2350         if (!atomic_dec_and_test(&tlink->tl_count) ||
2351             test_bit(TCON_LINK_IN_TREE, &tlink->tl_flags)) {
2352                 tlink->tl_time = jiffies;
2353                 return;
2354         }
2355
2356         if (!IS_ERR(tlink_tcon(tlink)))
2357                 cifs_put_tcon(tlink_tcon(tlink));
2358         kfree(tlink);
2359         return;
2360 }
2361
2362 static int
2363 compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
2364 {
2365         struct cifs_sb_info *old = CIFS_SB(sb);
2366         struct cifs_sb_info *new = mnt_data->cifs_sb;
2367         unsigned int oldflags = old->mnt_cifs_flags & CIFS_MOUNT_MASK;
2368         unsigned int newflags = new->mnt_cifs_flags & CIFS_MOUNT_MASK;
2369
2370         if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
2371                 return 0;
2372
2373         if (old->mnt_cifs_serverino_autodisabled)
2374                 newflags &= ~CIFS_MOUNT_SERVER_INUM;
2375
2376         if (oldflags != newflags)
2377                 return 0;
2378
2379         /*
2380          * We want to share sb only if we don't specify an r/wsize or
2381          * specified r/wsize is greater than or equal to existing one.
2382          */
2383         if (new->ctx->wsize && new->ctx->wsize < old->ctx->wsize)
2384                 return 0;
2385
2386         if (new->ctx->rsize && new->ctx->rsize < old->ctx->rsize)
2387                 return 0;
2388
2389         if (!uid_eq(old->ctx->linux_uid, new->ctx->linux_uid) ||
2390             !gid_eq(old->ctx->linux_gid, new->ctx->linux_gid))
2391                 return 0;
2392
2393         if (old->ctx->file_mode != new->ctx->file_mode ||
2394             old->ctx->dir_mode != new->ctx->dir_mode)
2395                 return 0;
2396
2397         if (strcmp(old->local_nls->charset, new->local_nls->charset))
2398                 return 0;
2399
2400         if (old->ctx->acregmax != new->ctx->acregmax)
2401                 return 0;
2402         if (old->ctx->acdirmax != new->ctx->acdirmax)
2403                 return 0;
2404
2405         return 1;
2406 }
2407
2408 static int
2409 match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
2410 {
2411         struct cifs_sb_info *old = CIFS_SB(sb);
2412         struct cifs_sb_info *new = mnt_data->cifs_sb;
2413         bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2414                 old->prepath;
2415         bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2416                 new->prepath;
2417
2418         if (old_set && new_set && !strcmp(new->prepath, old->prepath))
2419                 return 1;
2420         else if (!old_set && !new_set)
2421                 return 1;
2422
2423         return 0;
2424 }
2425
2426 int
2427 cifs_match_super(struct super_block *sb, void *data)
2428 {
2429         struct cifs_mnt_data *mnt_data = (struct cifs_mnt_data *)data;
2430         struct smb3_fs_context *ctx;
2431         struct cifs_sb_info *cifs_sb;
2432         struct TCP_Server_Info *tcp_srv;
2433         struct cifs_ses *ses;
2434         struct cifs_tcon *tcon;
2435         struct tcon_link *tlink;
2436         int rc = 0;
2437
2438         spin_lock(&cifs_tcp_ses_lock);
2439         cifs_sb = CIFS_SB(sb);
2440         tlink = cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
2441         if (tlink == NULL) {
2442                 /* can not match superblock if tlink were ever null */
2443                 spin_unlock(&cifs_tcp_ses_lock);
2444                 return 0;
2445         }
2446         tcon = tlink_tcon(tlink);
2447         ses = tcon->ses;
2448         tcp_srv = ses->server;
2449
2450         ctx = mnt_data->ctx;
2451
2452         if (!match_server(tcp_srv, ctx) ||
2453             !match_session(ses, ctx) ||
2454             !match_tcon(tcon, ctx) ||
2455             !match_prepath(sb, mnt_data)) {
2456                 rc = 0;
2457                 goto out;
2458         }
2459
2460         rc = compare_mount_options(sb, mnt_data);
2461 out:
2462         spin_unlock(&cifs_tcp_ses_lock);
2463         cifs_put_tlink(tlink);
2464         return rc;
2465 }
2466
2467 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2468 static struct lock_class_key cifs_key[2];
2469 static struct lock_class_key cifs_slock_key[2];
2470
2471 static inline void
2472 cifs_reclassify_socket4(struct socket *sock)
2473 {
2474         struct sock *sk = sock->sk;
2475         BUG_ON(!sock_allow_reclassification(sk));
2476         sock_lock_init_class_and_name(sk, "slock-AF_INET-CIFS",
2477                 &cifs_slock_key[0], "sk_lock-AF_INET-CIFS", &cifs_key[0]);
2478 }
2479
2480 static inline void
2481 cifs_reclassify_socket6(struct socket *sock)
2482 {
2483         struct sock *sk = sock->sk;
2484         BUG_ON(!sock_allow_reclassification(sk));
2485         sock_lock_init_class_and_name(sk, "slock-AF_INET6-CIFS",
2486                 &cifs_slock_key[1], "sk_lock-AF_INET6-CIFS", &cifs_key[1]);
2487 }
2488 #else
2489 static inline void
2490 cifs_reclassify_socket4(struct socket *sock)
2491 {
2492 }
2493
2494 static inline void
2495 cifs_reclassify_socket6(struct socket *sock)
2496 {
2497 }
2498 #endif
2499
2500 /* See RFC1001 section 14 on representation of Netbios names */
2501 static void rfc1002mangle(char *target, char *source, unsigned int length)
2502 {
2503         unsigned int i, j;
2504
2505         for (i = 0, j = 0; i < (length); i++) {
2506                 /* mask a nibble at a time and encode */
2507                 target[j] = 'A' + (0x0F & (source[i] >> 4));
2508                 target[j+1] = 'A' + (0x0F & source[i]);
2509                 j += 2;
2510         }
2511
2512 }
2513
2514 static int
2515 bind_socket(struct TCP_Server_Info *server)
2516 {
2517         int rc = 0;
2518         if (server->srcaddr.ss_family != AF_UNSPEC) {
2519                 /* Bind to the specified local IP address */
2520                 struct socket *socket = server->ssocket;
2521                 rc = socket->ops->bind(socket,
2522                                        (struct sockaddr *) &server->srcaddr,
2523                                        sizeof(server->srcaddr));
2524                 if (rc < 0) {
2525                         struct sockaddr_in *saddr4;
2526                         struct sockaddr_in6 *saddr6;
2527                         saddr4 = (struct sockaddr_in *)&server->srcaddr;
2528                         saddr6 = (struct sockaddr_in6 *)&server->srcaddr;
2529                         if (saddr6->sin6_family == AF_INET6)
2530                                 cifs_server_dbg(VFS, "Failed to bind to: %pI6c, error: %d\n",
2531                                          &saddr6->sin6_addr, rc);
2532                         else
2533                                 cifs_server_dbg(VFS, "Failed to bind to: %pI4, error: %d\n",
2534                                          &saddr4->sin_addr.s_addr, rc);
2535                 }
2536         }
2537         return rc;
2538 }
2539
2540 static int
2541 ip_rfc1001_connect(struct TCP_Server_Info *server)
2542 {
2543         int rc = 0;
2544         /*
2545          * some servers require RFC1001 sessinit before sending
2546          * negprot - BB check reconnection in case where second
2547          * sessinit is sent but no second negprot
2548          */
2549         struct rfc1002_session_packet *ses_init_buf;
2550         struct smb_hdr *smb_buf;
2551         ses_init_buf = kzalloc(sizeof(struct rfc1002_session_packet),
2552                                GFP_KERNEL);
2553         if (ses_init_buf) {
2554                 ses_init_buf->trailer.session_req.called_len = 32;
2555
2556                 if (server->server_RFC1001_name[0] != 0)
2557                         rfc1002mangle(ses_init_buf->trailer.
2558                                       session_req.called_name,
2559                                       server->server_RFC1001_name,
2560                                       RFC1001_NAME_LEN_WITH_NULL);
2561                 else
2562                         rfc1002mangle(ses_init_buf->trailer.
2563                                       session_req.called_name,
2564                                       DEFAULT_CIFS_CALLED_NAME,
2565                                       RFC1001_NAME_LEN_WITH_NULL);
2566
2567                 ses_init_buf->trailer.session_req.calling_len = 32;
2568
2569                 /*
2570                  * calling name ends in null (byte 16) from old smb
2571                  * convention.
2572                  */
2573                 if (server->workstation_RFC1001_name[0] != 0)
2574                         rfc1002mangle(ses_init_buf->trailer.
2575                                       session_req.calling_name,
2576                                       server->workstation_RFC1001_name,
2577                                       RFC1001_NAME_LEN_WITH_NULL);
2578                 else
2579                         rfc1002mangle(ses_init_buf->trailer.
2580                                       session_req.calling_name,
2581                                       "LINUX_CIFS_CLNT",
2582                                       RFC1001_NAME_LEN_WITH_NULL);
2583
2584                 ses_init_buf->trailer.session_req.scope1 = 0;
2585                 ses_init_buf->trailer.session_req.scope2 = 0;
2586                 smb_buf = (struct smb_hdr *)ses_init_buf;
2587
2588                 /* sizeof RFC1002_SESSION_REQUEST with no scope */
2589                 smb_buf->smb_buf_length = cpu_to_be32(0x81000044);
2590                 rc = smb_send(server, smb_buf, 0x44);
2591                 kfree(ses_init_buf);
2592                 /*
2593                  * RFC1001 layer in at least one server
2594                  * requires very short break before negprot
2595                  * presumably because not expecting negprot
2596                  * to follow so fast.  This is a simple
2597                  * solution that works without
2598                  * complicating the code and causes no
2599                  * significant slowing down on mount
2600                  * for everyone else
2601                  */
2602                 usleep_range(1000, 2000);
2603         }
2604         /*
2605          * else the negprot may still work without this
2606          * even though malloc failed
2607          */
2608
2609         return rc;
2610 }
2611
2612 static int
2613 generic_ip_connect(struct TCP_Server_Info *server)
2614 {
2615         int rc = 0;
2616         __be16 sport;
2617         int slen, sfamily;
2618         struct socket *socket = server->ssocket;
2619         struct sockaddr *saddr;
2620
2621         saddr = (struct sockaddr *) &server->dstaddr;
2622
2623         if (server->dstaddr.ss_family == AF_INET6) {
2624                 struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)&server->dstaddr;
2625
2626                 sport = ipv6->sin6_port;
2627                 slen = sizeof(struct sockaddr_in6);
2628                 sfamily = AF_INET6;
2629                 cifs_dbg(FYI, "%s: connecting to [%pI6]:%d\n", __func__, &ipv6->sin6_addr,
2630                                 ntohs(sport));
2631         } else {
2632                 struct sockaddr_in *ipv4 = (struct sockaddr_in *)&server->dstaddr;
2633
2634                 sport = ipv4->sin_port;
2635                 slen = sizeof(struct sockaddr_in);
2636                 sfamily = AF_INET;
2637                 cifs_dbg(FYI, "%s: connecting to %pI4:%d\n", __func__, &ipv4->sin_addr,
2638                                 ntohs(sport));
2639         }
2640
2641         if (socket == NULL) {
2642                 rc = __sock_create(cifs_net_ns(server), sfamily, SOCK_STREAM,
2643                                    IPPROTO_TCP, &socket, 1);
2644                 if (rc < 0) {
2645                         cifs_server_dbg(VFS, "Error %d creating socket\n", rc);
2646                         server->ssocket = NULL;
2647                         return rc;
2648                 }
2649
2650                 /* BB other socket options to set KEEPALIVE, NODELAY? */
2651                 cifs_dbg(FYI, "Socket created\n");
2652                 server->ssocket = socket;
2653                 socket->sk->sk_allocation = GFP_NOFS;
2654                 if (sfamily == AF_INET6)
2655                         cifs_reclassify_socket6(socket);
2656                 else
2657                         cifs_reclassify_socket4(socket);
2658         }
2659
2660         rc = bind_socket(server);
2661         if (rc < 0)
2662                 return rc;
2663
2664         /*
2665          * Eventually check for other socket options to change from
2666          * the default. sock_setsockopt not used because it expects
2667          * user space buffer
2668          */
2669         socket->sk->sk_rcvtimeo = 7 * HZ;
2670         socket->sk->sk_sndtimeo = 5 * HZ;
2671
2672         /* make the bufsizes depend on wsize/rsize and max requests */
2673         if (server->noautotune) {
2674                 if (socket->sk->sk_sndbuf < (200 * 1024))
2675                         socket->sk->sk_sndbuf = 200 * 1024;
2676                 if (socket->sk->sk_rcvbuf < (140 * 1024))
2677                         socket->sk->sk_rcvbuf = 140 * 1024;
2678         }
2679
2680         if (server->tcp_nodelay)
2681                 tcp_sock_set_nodelay(socket->sk);
2682
2683         cifs_dbg(FYI, "sndbuf %d rcvbuf %d rcvtimeo 0x%lx\n",
2684                  socket->sk->sk_sndbuf,
2685                  socket->sk->sk_rcvbuf, socket->sk->sk_rcvtimeo);
2686
2687         rc = socket->ops->connect(socket, saddr, slen,
2688                                   server->noblockcnt ? O_NONBLOCK : 0);
2689         /*
2690          * When mounting SMB root file systems, we do not want to block in
2691          * connect. Otherwise bail out and then let cifs_reconnect() perform
2692          * reconnect failover - if possible.
2693          */
2694         if (server->noblockcnt && rc == -EINPROGRESS)
2695                 rc = 0;
2696         if (rc < 0) {
2697                 cifs_dbg(FYI, "Error %d connecting to server\n", rc);
2698                 trace_smb3_connect_err(server->hostname, server->conn_id, &server->dstaddr, rc);
2699                 sock_release(socket);
2700                 server->ssocket = NULL;
2701                 return rc;
2702         }
2703         trace_smb3_connect_done(server->hostname, server->conn_id, &server->dstaddr);
2704         if (sport == htons(RFC1001_PORT))
2705                 rc = ip_rfc1001_connect(server);
2706
2707         return rc;
2708 }
2709
2710 static int
2711 ip_connect(struct TCP_Server_Info *server)
2712 {
2713         __be16 *sport;
2714         struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
2715         struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
2716
2717         if (server->dstaddr.ss_family == AF_INET6)
2718                 sport = &addr6->sin6_port;
2719         else
2720                 sport = &addr->sin_port;
2721
2722         if (*sport == 0) {
2723                 int rc;
2724
2725                 /* try with 445 port at first */
2726                 *sport = htons(CIFS_PORT);
2727
2728                 rc = generic_ip_connect(server);
2729                 if (rc >= 0)
2730                         return rc;
2731
2732                 /* if it failed, try with 139 port */
2733                 *sport = htons(RFC1001_PORT);
2734         }
2735
2736         return generic_ip_connect(server);
2737 }
2738
2739 void reset_cifs_unix_caps(unsigned int xid, struct cifs_tcon *tcon,
2740                           struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
2741 {
2742         /*
2743          * If we are reconnecting then should we check to see if
2744          * any requested capabilities changed locally e.g. via
2745          * remount but we can not do much about it here
2746          * if they have (even if we could detect it by the following)
2747          * Perhaps we could add a backpointer to array of sb from tcon
2748          * or if we change to make all sb to same share the same
2749          * sb as NFS - then we only have one backpointer to sb.
2750          * What if we wanted to mount the server share twice once with
2751          * and once without posixacls or posix paths?
2752          */
2753         __u64 saved_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
2754
2755         if (ctx && ctx->no_linux_ext) {
2756                 tcon->fsUnixInfo.Capability = 0;
2757                 tcon->unix_ext = 0; /* Unix Extensions disabled */
2758                 cifs_dbg(FYI, "Linux protocol extensions disabled\n");
2759                 return;
2760         } else if (ctx)
2761                 tcon->unix_ext = 1; /* Unix Extensions supported */
2762
2763         if (!tcon->unix_ext) {
2764                 cifs_dbg(FYI, "Unix extensions disabled so not set on reconnect\n");
2765                 return;
2766         }
2767
2768         if (!CIFSSMBQFSUnixInfo(xid, tcon)) {
2769                 __u64 cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
2770                 cifs_dbg(FYI, "unix caps which server supports %lld\n", cap);
2771                 /*
2772                  * check for reconnect case in which we do not
2773                  * want to change the mount behavior if we can avoid it
2774                  */
2775                 if (ctx == NULL) {
2776                         /*
2777                          * turn off POSIX ACL and PATHNAMES if not set
2778                          * originally at mount time
2779                          */
2780                         if ((saved_cap & CIFS_UNIX_POSIX_ACL_CAP) == 0)
2781                                 cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
2782                         if ((saved_cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
2783                                 if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
2784                                         cifs_dbg(VFS, "POSIXPATH support change\n");
2785                                 cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
2786                         } else if ((cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
2787                                 cifs_dbg(VFS, "possible reconnect error\n");
2788                                 cifs_dbg(VFS, "server disabled POSIX path support\n");
2789                         }
2790                 }
2791
2792                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
2793                         cifs_dbg(VFS, "per-share encryption not supported yet\n");
2794
2795                 cap &= CIFS_UNIX_CAP_MASK;
2796                 if (ctx && ctx->no_psx_acl)
2797                         cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
2798                 else if (CIFS_UNIX_POSIX_ACL_CAP & cap) {
2799                         cifs_dbg(FYI, "negotiated posix acl support\n");
2800                         if (cifs_sb)
2801                                 cifs_sb->mnt_cifs_flags |=
2802                                         CIFS_MOUNT_POSIXACL;
2803                 }
2804
2805                 if (ctx && ctx->posix_paths == 0)
2806                         cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
2807                 else if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) {
2808                         cifs_dbg(FYI, "negotiate posix pathnames\n");
2809                         if (cifs_sb)
2810                                 cifs_sb->mnt_cifs_flags |=
2811                                         CIFS_MOUNT_POSIX_PATHS;
2812                 }
2813
2814                 cifs_dbg(FYI, "Negotiate caps 0x%x\n", (int)cap);
2815 #ifdef CONFIG_CIFS_DEBUG2
2816                 if (cap & CIFS_UNIX_FCNTL_CAP)
2817                         cifs_dbg(FYI, "FCNTL cap\n");
2818                 if (cap & CIFS_UNIX_EXTATTR_CAP)
2819                         cifs_dbg(FYI, "EXTATTR cap\n");
2820                 if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
2821                         cifs_dbg(FYI, "POSIX path cap\n");
2822                 if (cap & CIFS_UNIX_XATTR_CAP)
2823                         cifs_dbg(FYI, "XATTR cap\n");
2824                 if (cap & CIFS_UNIX_POSIX_ACL_CAP)
2825                         cifs_dbg(FYI, "POSIX ACL cap\n");
2826                 if (cap & CIFS_UNIX_LARGE_READ_CAP)
2827                         cifs_dbg(FYI, "very large read cap\n");
2828                 if (cap & CIFS_UNIX_LARGE_WRITE_CAP)
2829                         cifs_dbg(FYI, "very large write cap\n");
2830                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_CAP)
2831                         cifs_dbg(FYI, "transport encryption cap\n");
2832                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
2833                         cifs_dbg(FYI, "mandatory transport encryption cap\n");
2834 #endif /* CIFS_DEBUG2 */
2835                 if (CIFSSMBSetFSUnixInfo(xid, tcon, cap)) {
2836                         if (ctx == NULL)
2837                                 cifs_dbg(FYI, "resetting capabilities failed\n");
2838                         else
2839                                 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");
2840
2841                 }
2842         }
2843 }
2844
2845 int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb)
2846 {
2847         struct smb3_fs_context *ctx = cifs_sb->ctx;
2848
2849         INIT_DELAYED_WORK(&cifs_sb->prune_tlinks, cifs_prune_tlinks);
2850
2851         spin_lock_init(&cifs_sb->tlink_tree_lock);
2852         cifs_sb->tlink_tree = RB_ROOT;
2853
2854         cifs_dbg(FYI, "file mode: %04ho  dir mode: %04ho\n",
2855                  ctx->file_mode, ctx->dir_mode);
2856
2857         /* this is needed for ASCII cp to Unicode converts */
2858         if (ctx->iocharset == NULL) {
2859                 /* load_nls_default cannot return null */
2860                 cifs_sb->local_nls = load_nls_default();
2861         } else {
2862                 cifs_sb->local_nls = load_nls(ctx->iocharset);
2863                 if (cifs_sb->local_nls == NULL) {
2864                         cifs_dbg(VFS, "CIFS mount error: iocharset %s not found\n",
2865                                  ctx->iocharset);
2866                         return -ELIBACC;
2867                 }
2868         }
2869         ctx->local_nls = cifs_sb->local_nls;
2870
2871         smb3_update_mnt_flags(cifs_sb);
2872
2873         if (ctx->direct_io)
2874                 cifs_dbg(FYI, "mounting share using direct i/o\n");
2875         if (ctx->cache_ro) {
2876                 cifs_dbg(VFS, "mounting share with read only caching. Ensure that the share will not be modified while in use.\n");
2877                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RO_CACHE;
2878         } else if (ctx->cache_rw) {
2879                 cifs_dbg(VFS, "mounting share in single client RW caching mode. Ensure that no other systems will be accessing the share.\n");
2880                 cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_RO_CACHE |
2881                                             CIFS_MOUNT_RW_CACHE);
2882         }
2883
2884         if ((ctx->cifs_acl) && (ctx->dynperm))
2885                 cifs_dbg(VFS, "mount option dynperm ignored if cifsacl mount option supported\n");
2886
2887         if (ctx->prepath) {
2888                 cifs_sb->prepath = kstrdup(ctx->prepath, GFP_KERNEL);
2889                 if (cifs_sb->prepath == NULL)
2890                         return -ENOMEM;
2891                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
2892         }
2893
2894         return 0;
2895 }
2896
2897 /* Release all succeed connections */
2898 static inline void mount_put_conns(struct cifs_sb_info *cifs_sb,
2899                                    unsigned int xid,
2900                                    struct TCP_Server_Info *server,
2901                                    struct cifs_ses *ses, struct cifs_tcon *tcon)
2902 {
2903         int rc = 0;
2904
2905         if (tcon)
2906                 cifs_put_tcon(tcon);
2907         else if (ses)
2908                 cifs_put_smb_ses(ses);
2909         else if (server)
2910                 cifs_put_tcp_session(server, 0);
2911         cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
2912         free_xid(xid);
2913 }
2914
2915 /* Get connections for tcp, ses and tcon */
2916 static int mount_get_conns(struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
2917                            unsigned int *xid,
2918                            struct TCP_Server_Info **nserver,
2919                            struct cifs_ses **nses, struct cifs_tcon **ntcon)
2920 {
2921         int rc = 0;
2922         struct TCP_Server_Info *server;
2923         struct cifs_ses *ses;
2924         struct cifs_tcon *tcon;
2925
2926         *nserver = NULL;
2927         *nses = NULL;
2928         *ntcon = NULL;
2929
2930         *xid = get_xid();
2931
2932         /* get a reference to a tcp session */
2933         server = cifs_get_tcp_session(ctx);
2934         if (IS_ERR(server)) {
2935                 rc = PTR_ERR(server);
2936                 return rc;
2937         }
2938
2939         *nserver = server;
2940
2941         /* get a reference to a SMB session */
2942         ses = cifs_get_smb_ses(server, ctx);
2943         if (IS_ERR(ses)) {
2944                 rc = PTR_ERR(ses);
2945                 return rc;
2946         }
2947
2948         *nses = ses;
2949
2950         if ((ctx->persistent == true) && (!(ses->server->capabilities &
2951                                             SMB2_GLOBAL_CAP_PERSISTENT_HANDLES))) {
2952                 cifs_server_dbg(VFS, "persistent handles not supported by server\n");
2953                 return -EOPNOTSUPP;
2954         }
2955
2956         /* search for existing tcon to this server share */
2957         tcon = cifs_get_tcon(ses, ctx);
2958         if (IS_ERR(tcon)) {
2959                 rc = PTR_ERR(tcon);
2960                 return rc;
2961         }
2962
2963         *ntcon = tcon;
2964
2965         /* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
2966         if (tcon->posix_extensions)
2967                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_POSIX_PATHS;
2968
2969         /* tell server which Unix caps we support */
2970         if (cap_unix(tcon->ses)) {
2971                 /*
2972                  * reset of caps checks mount to see if unix extensions disabled
2973                  * for just this mount.
2974                  */
2975                 reset_cifs_unix_caps(*xid, tcon, cifs_sb, ctx);
2976                 if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
2977                     (le64_to_cpu(tcon->fsUnixInfo.Capability) &
2978                      CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP))
2979                         return -EACCES;
2980         } else
2981                 tcon->unix_ext = 0; /* server does not support them */
2982
2983         /* do not care if a following call succeed - informational */
2984         if (!tcon->pipe && server->ops->qfs_tcon) {
2985                 server->ops->qfs_tcon(*xid, tcon, cifs_sb);
2986                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RO_CACHE) {
2987                         if (tcon->fsDevInfo.DeviceCharacteristics &
2988                             cpu_to_le32(FILE_READ_ONLY_DEVICE))
2989                                 cifs_dbg(VFS, "mounted to read only share\n");
2990                         else if ((cifs_sb->mnt_cifs_flags &
2991                                   CIFS_MOUNT_RW_CACHE) == 0)
2992                                 cifs_dbg(VFS, "read only mount of RW share\n");
2993                         /* no need to log a RW mount of a typical RW share */
2994                 }
2995         }
2996
2997         /*
2998          * Clamp the rsize/wsize mount arguments if they are too big for the server
2999          * and set the rsize/wsize to the negotiated values if not passed in by
3000          * the user on mount
3001          */
3002         if ((cifs_sb->ctx->wsize == 0) ||
3003             (cifs_sb->ctx->wsize > server->ops->negotiate_wsize(tcon, ctx)))
3004                 cifs_sb->ctx->wsize = server->ops->negotiate_wsize(tcon, ctx);
3005         if ((cifs_sb->ctx->rsize == 0) ||
3006             (cifs_sb->ctx->rsize > server->ops->negotiate_rsize(tcon, ctx)))
3007                 cifs_sb->ctx->rsize = server->ops->negotiate_rsize(tcon, ctx);
3008
3009         return 0;
3010 }
3011
3012 static int mount_setup_tlink(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
3013                              struct cifs_tcon *tcon)
3014 {
3015         struct tcon_link *tlink;
3016
3017         /* hang the tcon off of the superblock */
3018         tlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
3019         if (tlink == NULL)
3020                 return -ENOMEM;
3021
3022         tlink->tl_uid = ses->linux_uid;
3023         tlink->tl_tcon = tcon;
3024         tlink->tl_time = jiffies;
3025         set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
3026         set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3027
3028         cifs_sb->master_tlink = tlink;
3029         spin_lock(&cifs_sb->tlink_tree_lock);
3030         tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
3031         spin_unlock(&cifs_sb->tlink_tree_lock);
3032
3033         queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
3034                                 TLINK_IDLE_EXPIRE);
3035         return 0;
3036 }
3037
3038 #ifdef CONFIG_CIFS_DFS_UPCALL
3039 static int mount_get_dfs_conns(struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
3040                                unsigned int *xid, struct TCP_Server_Info **nserver,
3041                                struct cifs_ses **nses, struct cifs_tcon **ntcon)
3042 {
3043         int rc;
3044
3045         ctx->nosharesock = true;
3046         rc = mount_get_conns(ctx, cifs_sb, xid, nserver, nses, ntcon);
3047         if (*nserver) {
3048                 cifs_dbg(FYI, "%s: marking tcp session as a dfs connection\n", __func__);
3049                 spin_lock(&cifs_tcp_ses_lock);
3050                 (*nserver)->is_dfs_conn = true;
3051                 spin_unlock(&cifs_tcp_ses_lock);
3052         }
3053         return rc;
3054 }
3055
3056 /*
3057  * cifs_build_path_to_root returns full path to root when we do not have an
3058  * existing connection (tcon)
3059  */
3060 static char *
3061 build_unc_path_to_root(const struct smb3_fs_context *ctx,
3062                        const struct cifs_sb_info *cifs_sb, bool useppath)
3063 {
3064         char *full_path, *pos;
3065         unsigned int pplen = useppath && ctx->prepath ?
3066                 strlen(ctx->prepath) + 1 : 0;
3067         unsigned int unc_len = strnlen(ctx->UNC, MAX_TREE_SIZE + 1);
3068
3069         if (unc_len > MAX_TREE_SIZE)
3070                 return ERR_PTR(-EINVAL);
3071
3072         full_path = kmalloc(unc_len + pplen + 1, GFP_KERNEL);
3073         if (full_path == NULL)
3074                 return ERR_PTR(-ENOMEM);
3075
3076         memcpy(full_path, ctx->UNC, unc_len);
3077         pos = full_path + unc_len;
3078
3079         if (pplen) {
3080                 *pos = CIFS_DIR_SEP(cifs_sb);
3081                 memcpy(pos + 1, ctx->prepath, pplen);
3082                 pos += pplen;
3083         }
3084
3085         *pos = '\0'; /* add trailing null */
3086         convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb));
3087         cifs_dbg(FYI, "%s: full_path=%s\n", __func__, full_path);
3088         return full_path;
3089 }
3090
3091 /*
3092  * expand_dfs_referral - Perform a dfs referral query and update the cifs_sb
3093  *
3094  * If a referral is found, cifs_sb->ctx->mount_options will be (re-)allocated
3095  * to a string containing updated options for the submount.  Otherwise it
3096  * will be left untouched.
3097  *
3098  * Returns the rc from get_dfs_path to the caller, which can be used to
3099  * determine whether there were referrals.
3100  */
3101 static int
3102 expand_dfs_referral(const unsigned int xid, struct cifs_ses *ses,
3103                     struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
3104                     char *ref_path)
3105 {
3106         int rc;
3107         struct dfs_info3_param referral = {0};
3108         char *full_path = NULL, *mdata = NULL;
3109
3110         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
3111                 return -EREMOTE;
3112
3113         full_path = build_unc_path_to_root(ctx, cifs_sb, true);
3114         if (IS_ERR(full_path))
3115                 return PTR_ERR(full_path);
3116
3117         rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
3118                             ref_path, &referral, NULL);
3119         if (!rc) {
3120                 char *fake_devname = NULL;
3121
3122                 mdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options,
3123                                                    full_path + 1, &referral,
3124                                                    &fake_devname);
3125                 free_dfs_info_param(&referral);
3126
3127                 if (IS_ERR(mdata)) {
3128                         rc = PTR_ERR(mdata);
3129                         mdata = NULL;
3130                 } else {
3131                         /*
3132                          * We can not clear out the whole structure since we
3133                          * no longer have an explicit function to parse
3134                          * a mount-string. Instead we need to clear out the
3135                          * individual fields that are no longer valid.
3136                          */
3137                         kfree(ctx->prepath);
3138                         ctx->prepath = NULL;
3139                         rc = cifs_setup_volume_info(ctx, mdata, fake_devname);
3140                 }
3141                 kfree(fake_devname);
3142                 kfree(cifs_sb->ctx->mount_options);
3143                 cifs_sb->ctx->mount_options = mdata;
3144         }
3145         kfree(full_path);
3146         return rc;
3147 }
3148
3149 static int get_next_dfs_tgt(struct dfs_cache_tgt_list *tgt_list,
3150                             struct dfs_cache_tgt_iterator **tgt_it)
3151 {
3152         if (!*tgt_it)
3153                 *tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
3154         else
3155                 *tgt_it = dfs_cache_get_next_tgt(tgt_list, *tgt_it);
3156         return !*tgt_it ? -EHOSTDOWN : 0;
3157 }
3158
3159 static int update_vol_info(const struct dfs_cache_tgt_iterator *tgt_it,
3160                            struct smb3_fs_context *fake_ctx, struct smb3_fs_context *ctx)
3161 {
3162         const char *tgt = dfs_cache_get_tgt_name(tgt_it);
3163         int len = strlen(tgt) + 2;
3164         char *new_unc;
3165
3166         new_unc = kmalloc(len, GFP_KERNEL);
3167         if (!new_unc)
3168                 return -ENOMEM;
3169         scnprintf(new_unc, len, "\\%s", tgt);
3170
3171         kfree(ctx->UNC);
3172         ctx->UNC = new_unc;
3173
3174         if (fake_ctx->prepath) {
3175                 kfree(ctx->prepath);
3176                 ctx->prepath = fake_ctx->prepath;
3177                 fake_ctx->prepath = NULL;
3178         }
3179         memcpy(&ctx->dstaddr, &fake_ctx->dstaddr, sizeof(ctx->dstaddr));
3180
3181         return 0;
3182 }
3183
3184 static int do_dfs_failover(const char *path, const char *full_path, struct cifs_sb_info *cifs_sb,
3185                            struct smb3_fs_context *ctx, struct cifs_ses *root_ses,
3186                            unsigned int *xid, struct TCP_Server_Info **server,
3187                            struct cifs_ses **ses, struct cifs_tcon **tcon)
3188 {
3189         int rc;
3190         char *npath = NULL;
3191         struct dfs_cache_tgt_list tgt_list = DFS_CACHE_TGT_LIST_INIT(tgt_list);
3192         struct dfs_cache_tgt_iterator *tgt_it = NULL;
3193         struct smb3_fs_context tmp_ctx = {NULL};
3194
3195         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
3196                 return -EOPNOTSUPP;
3197
3198         npath = dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));
3199         if (IS_ERR(npath))
3200                 return PTR_ERR(npath);
3201
3202         cifs_dbg(FYI, "%s: path=%s full_path=%s\n", __func__, npath, full_path);
3203
3204         rc = dfs_cache_noreq_find(npath, NULL, &tgt_list);
3205         if (rc)
3206                 goto out;
3207         /*
3208          * We use a 'tmp_ctx' here because we need pass it down to the mount_{get,put} functions to
3209          * test connection against new DFS targets.
3210          */
3211         rc = smb3_fs_context_dup(&tmp_ctx, ctx);
3212         if (rc)
3213                 goto out;
3214
3215         for (;;) {
3216                 struct dfs_info3_param ref = {0};
3217                 char *fake_devname = NULL, *mdata = NULL;
3218
3219                 /* Get next DFS target server - if any */
3220                 rc = get_next_dfs_tgt(&tgt_list, &tgt_it);
3221                 if (rc)
3222                         break;
3223
3224                 rc = dfs_cache_get_tgt_referral(npath, tgt_it, &ref);
3225                 if (rc)
3226                         break;
3227
3228                 cifs_dbg(FYI, "%s: old ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
3229                          tmp_ctx.prepath);
3230
3231                 mdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options, full_path + 1, &ref,
3232                                                    &fake_devname);
3233                 free_dfs_info_param(&ref);
3234
3235                 if (IS_ERR(mdata)) {
3236                         rc = PTR_ERR(mdata);
3237                         mdata = NULL;
3238                 } else
3239                         rc = cifs_setup_volume_info(&tmp_ctx, mdata, fake_devname);
3240
3241                 kfree(mdata);
3242                 kfree(fake_devname);
3243
3244                 if (rc)
3245                         break;
3246
3247                 cifs_dbg(FYI, "%s: new ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
3248                          tmp_ctx.prepath);
3249
3250                 mount_put_conns(cifs_sb, *xid, *server, *ses, *tcon);
3251                 rc = mount_get_dfs_conns(&tmp_ctx, cifs_sb, xid, server, ses, tcon);
3252                 if (!rc || (*server && *ses)) {
3253                         /*
3254                          * We were able to connect to new target server. Update current context with
3255                          * new target server.
3256                          */
3257                         rc = update_vol_info(tgt_it, &tmp_ctx, ctx);
3258                         break;
3259                 }
3260         }
3261         if (!rc) {
3262                 cifs_dbg(FYI, "%s: final ctx: UNC=%s prepath=%s\n", __func__, tmp_ctx.UNC,
3263                          tmp_ctx.prepath);
3264                 /*
3265                  * Update DFS target hint in DFS referral cache with the target server we
3266                  * successfully reconnected to.
3267                  */
3268                 rc = dfs_cache_update_tgthint(*xid, root_ses ? root_ses : *ses, cifs_sb->local_nls,
3269                                               cifs_remap(cifs_sb), path, tgt_it);
3270         }
3271
3272 out:
3273         kfree(npath);
3274         smb3_cleanup_fs_context_contents(&tmp_ctx);
3275         dfs_cache_free_tgts(&tgt_list);
3276         return rc;
3277 }
3278 #endif
3279
3280 /* TODO: all callers to this are broken. We are not parsing mount_options here
3281  * we should pass a clone of the original context?
3282  */
3283 int
3284 cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname)
3285 {
3286         int rc;
3287
3288         if (devname) {
3289                 cifs_dbg(FYI, "%s: devname=%s\n", __func__, devname);
3290                 rc = smb3_parse_devname(devname, ctx);
3291                 if (rc) {
3292                         cifs_dbg(VFS, "%s: failed to parse %s: %d\n", __func__, devname, rc);
3293                         return rc;
3294                 }
3295         }
3296
3297         if (mntopts) {
3298                 char *ip;
3299
3300                 rc = smb3_parse_opt(mntopts, "ip", &ip);
3301                 if (rc) {
3302                         cifs_dbg(VFS, "%s: failed to parse ip options: %d\n", __func__, rc);
3303                         return rc;
3304                 }
3305
3306                 rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip));
3307                 kfree(ip);
3308                 if (!rc) {
3309                         cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);
3310                         return -EINVAL;
3311                 }
3312         }
3313
3314         if (ctx->nullauth) {
3315                 cifs_dbg(FYI, "Anonymous login\n");
3316                 kfree(ctx->username);
3317                 ctx->username = NULL;
3318         } else if (ctx->username) {
3319                 /* BB fixme parse for domain name here */
3320                 cifs_dbg(FYI, "Username: %s\n", ctx->username);
3321         } else {
3322                 cifs_dbg(VFS, "No username specified\n");
3323         /* In userspace mount helper we can get user name from alternate
3324            locations such as env variables and files on disk */
3325                 return -EINVAL;
3326         }
3327
3328         return 0;
3329 }
3330
3331 static int
3332 cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
3333                                         unsigned int xid,
3334                                         struct cifs_tcon *tcon,
3335                                         struct cifs_sb_info *cifs_sb,
3336                                         char *full_path,
3337                                         int added_treename)
3338 {
3339         int rc;
3340         char *s;
3341         char sep, tmp;
3342         int skip = added_treename ? 1 : 0;
3343
3344         sep = CIFS_DIR_SEP(cifs_sb);
3345         s = full_path;
3346
3347         rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, "");
3348         while (rc == 0) {
3349                 /* skip separators */
3350                 while (*s == sep)
3351                         s++;
3352                 if (!*s)
3353                         break;
3354                 /* next separator */
3355                 while (*s && *s != sep)
3356                         s++;
3357                 /*
3358                  * if the treename is added, we then have to skip the first
3359                  * part within the separators
3360                  */
3361                 if (skip) {
3362                         skip = 0;
3363                         continue;
3364                 }
3365                 /*
3366                  * temporarily null-terminate the path at the end of
3367                  * the current component
3368                  */
3369                 tmp = *s;
3370                 *s = 0;
3371                 rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3372                                                      full_path);
3373                 *s = tmp;
3374         }
3375         return rc;
3376 }
3377
3378 /*
3379  * Check if path is remote (e.g. a DFS share). Return -EREMOTE if it is,
3380  * otherwise 0.
3381  */
3382 static int is_path_remote(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx,
3383                           const unsigned int xid,
3384                           struct TCP_Server_Info *server,
3385                           struct cifs_tcon *tcon)
3386 {
3387         int rc;
3388         char *full_path;
3389
3390         if (!server->ops->is_path_accessible)
3391                 return -EOPNOTSUPP;
3392
3393         /*
3394          * cifs_build_path_to_root works only when we have a valid tcon
3395          */
3396         full_path = cifs_build_path_to_root(ctx, cifs_sb, tcon,
3397                                             tcon->Flags & SMB_SHARE_IS_IN_DFS);
3398         if (full_path == NULL)
3399                 return -ENOMEM;
3400
3401         cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
3402
3403         rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3404                                              full_path);
3405         if (rc != 0 && rc != -EREMOTE) {
3406                 kfree(full_path);
3407                 return rc;
3408         }
3409
3410         if (rc != -EREMOTE) {
3411                 rc = cifs_are_all_path_components_accessible(server, xid, tcon,
3412                         cifs_sb, full_path, tcon->Flags & SMB_SHARE_IS_IN_DFS);
3413                 if (rc != 0) {
3414                         cifs_server_dbg(VFS, "cannot query dirs between root and final path, enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
3415                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3416                         rc = 0;
3417                 }
3418         }
3419
3420         kfree(full_path);
3421         return rc;
3422 }
3423
3424 #ifdef CONFIG_CIFS_DFS_UPCALL
3425 static void set_root_ses(struct cifs_sb_info *cifs_sb, const uuid_t *mount_id, struct cifs_ses *ses,
3426                          struct cifs_ses **root_ses)
3427 {
3428         if (ses) {
3429                 spin_lock(&cifs_tcp_ses_lock);
3430                 ses->ses_count++;
3431                 spin_unlock(&cifs_tcp_ses_lock);
3432                 dfs_cache_add_refsrv_session(mount_id, ses);
3433         }
3434         *root_ses = ses;
3435 }
3436
3437 /* Set up next dfs prefix path in @dfs_path */
3438 static int next_dfs_prepath(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx,
3439                             const unsigned int xid, struct TCP_Server_Info *server,
3440                             struct cifs_tcon *tcon, char **dfs_path)
3441 {
3442         char *path, *npath;
3443         int added_treename = is_tcon_dfs(tcon);
3444         int rc;
3445
3446         path = cifs_build_path_to_root(ctx, cifs_sb, tcon, added_treename);
3447         if (!path)
3448                 return -ENOMEM;
3449
3450         rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
3451         if (rc == -EREMOTE) {
3452                 struct smb3_fs_context v = {NULL};
3453                 /* if @path contains a tree name, skip it in the prefix path */
3454                 if (added_treename) {
3455                         rc = smb3_parse_devname(path, &v);
3456                         if (rc)
3457                                 goto out;
3458                         npath = build_unc_path_to_root(&v, cifs_sb, true);
3459                         smb3_cleanup_fs_context_contents(&v);
3460                 } else {
3461                         v.UNC = ctx->UNC;
3462                         v.prepath = path + 1;
3463                         npath = build_unc_path_to_root(&v, cifs_sb, true);
3464                 }
3465
3466                 if (IS_ERR(npath)) {
3467                         rc = PTR_ERR(npath);
3468                         goto out;
3469                 }
3470
3471                 kfree(*dfs_path);
3472                 *dfs_path = npath;
3473                 rc = -EREMOTE;
3474         }
3475
3476 out:
3477         kfree(path);
3478         return rc;
3479 }
3480
3481 /* Check if resolved targets can handle any DFS referrals */
3482 static int is_referral_server(const char *ref_path, struct cifs_sb_info *cifs_sb,
3483                               struct cifs_tcon *tcon, bool *ref_server)
3484 {
3485         int rc;
3486         struct dfs_info3_param ref = {0};
3487
3488         cifs_dbg(FYI, "%s: ref_path=%s\n", __func__, ref_path);
3489
3490         if (is_tcon_dfs(tcon)) {
3491                 *ref_server = true;
3492         } else {
3493                 char *npath;
3494
3495                 npath = dfs_cache_canonical_path(ref_path, cifs_sb->local_nls, cifs_remap(cifs_sb));
3496                 if (IS_ERR(npath))
3497                         return PTR_ERR(npath);
3498
3499                 rc = dfs_cache_noreq_find(npath, &ref, NULL);
3500                 kfree(npath);
3501                 if (rc) {
3502                         cifs_dbg(VFS, "%s: dfs_cache_noreq_find: failed (rc=%d)\n", __func__, rc);
3503                         return rc;
3504                 }
3505                 cifs_dbg(FYI, "%s: ref.flags=0x%x\n", __func__, ref.flags);
3506                 /*
3507                  * Check if all targets are capable of handling DFS referrals as per
3508                  * MS-DFSC 2.2.4 RESP_GET_DFS_REFERRAL.
3509                  */
3510                 *ref_server = !!(ref.flags & DFSREF_REFERRAL_SERVER);
3511                 free_dfs_info_param(&ref);
3512         }
3513         return 0;
3514 }
3515
3516 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3517 {
3518         int rc = 0;
3519         unsigned int xid;
3520         struct TCP_Server_Info *server = NULL;
3521         struct cifs_ses *ses = NULL, *root_ses = NULL;
3522         struct cifs_tcon *tcon = NULL;
3523         int count = 0;
3524         uuid_t mount_id = {0};
3525         char *ref_path = NULL, *full_path = NULL;
3526         char *oldmnt = NULL;
3527         bool ref_server = false;
3528
3529         rc = mount_get_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
3530         /*
3531          * If called with 'nodfs' mount option, then skip DFS resolving.  Otherwise unconditionally
3532          * try to get an DFS referral (even cached) to determine whether it is an DFS mount.
3533          *
3534          * Skip prefix path to provide support for DFS referrals from w2k8 servers which don't seem
3535          * to respond with PATH_NOT_COVERED to requests that include the prefix.
3536          */
3537         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
3538             dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb), ctx->UNC + 1, NULL,
3539                            NULL)) {
3540                 if (rc)
3541                         goto error;
3542                 /* Check if it is fully accessible and then mount it */
3543                 rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
3544                 if (!rc)
3545                         goto out;
3546                 if (rc != -EREMOTE)
3547                         goto error;
3548         }
3549
3550         mount_put_conns(cifs_sb, xid, server, ses, tcon);
3551         /*
3552          * Ignore error check here because we may failover to other targets from cached a
3553          * referral.
3554          */
3555         (void)mount_get_dfs_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
3556
3557         /* Get path of DFS root */
3558         ref_path = build_unc_path_to_root(ctx, cifs_sb, false);
3559         if (IS_ERR(ref_path)) {
3560                 rc = PTR_ERR(ref_path);
3561                 ref_path = NULL;
3562                 goto error;
3563         }
3564
3565         uuid_gen(&mount_id);
3566         set_root_ses(cifs_sb, &mount_id, ses, &root_ses);
3567         do {
3568                 /* Save full path of last DFS path we used to resolve final target server */
3569                 kfree(full_path);
3570                 full_path = build_unc_path_to_root(ctx, cifs_sb, !!count);
3571                 if (IS_ERR(full_path)) {
3572                         rc = PTR_ERR(full_path);
3573                         full_path = NULL;
3574                         break;
3575                 }
3576                 /* Chase referral */
3577                 oldmnt = cifs_sb->ctx->mount_options;
3578                 rc = expand_dfs_referral(xid, root_ses, ctx, cifs_sb, ref_path + 1);
3579                 if (rc)
3580                         break;
3581                 /* Connect to new DFS target only if we were redirected */
3582                 if (oldmnt != cifs_sb->ctx->mount_options) {
3583                         mount_put_conns(cifs_sb, xid, server, ses, tcon);
3584                         rc = mount_get_dfs_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
3585                 }
3586                 if (rc && !server && !ses) {
3587                         /* Failed to connect. Try to connect to other targets in the referral. */
3588                         rc = do_dfs_failover(ref_path + 1, full_path, cifs_sb, ctx, root_ses, &xid,
3589                                              &server, &ses, &tcon);
3590                 }
3591                 if (rc == -EACCES || rc == -EOPNOTSUPP || !server || !ses)
3592                         break;
3593                 if (!tcon)
3594                         continue;
3595
3596                 /* Make sure that requests go through new root servers */
3597                 rc = is_referral_server(ref_path + 1, cifs_sb, tcon, &ref_server);
3598                 if (rc)
3599                         break;
3600                 if (ref_server)
3601                         set_root_ses(cifs_sb, &mount_id, ses, &root_ses);
3602
3603                 /* Get next dfs path and then continue chasing them if -EREMOTE */
3604                 rc = next_dfs_prepath(cifs_sb, ctx, xid, server, tcon, &ref_path);
3605                 /* Prevent recursion on broken link referrals */
3606                 if (rc == -EREMOTE && ++count > MAX_NESTED_LINKS)
3607                         rc = -ELOOP;
3608         } while (rc == -EREMOTE);
3609
3610         if (rc || !tcon || !ses)
3611                 goto error;
3612
3613         kfree(ref_path);
3614         /*
3615          * Store DFS full path in both superblock and tree connect structures.
3616          *
3617          * For DFS root mounts, the prefix path (cifs_sb->prepath) is preserved during reconnect so
3618          * only the root path is set in cifs_sb->origin_fullpath and tcon->dfs_path. And for DFS
3619          * links, the prefix path is included in both and may be changed during reconnect.  See
3620          * cifs_tree_connect().
3621          */
3622         ref_path = dfs_cache_canonical_path(full_path, cifs_sb->local_nls, cifs_remap(cifs_sb));
3623         kfree(full_path);
3624         full_path = NULL;
3625
3626         if (IS_ERR(ref_path)) {
3627                 rc = PTR_ERR(ref_path);
3628                 ref_path = NULL;
3629                 goto error;
3630         }
3631         cifs_sb->origin_fullpath = ref_path;
3632
3633         ref_path = kstrdup(cifs_sb->origin_fullpath, GFP_KERNEL);
3634         if (!ref_path) {
3635                 rc = -ENOMEM;
3636                 goto error;
3637         }
3638         spin_lock(&cifs_tcp_ses_lock);
3639         tcon->dfs_path = ref_path;
3640         ref_path = NULL;
3641         spin_unlock(&cifs_tcp_ses_lock);
3642
3643         /*
3644          * After reconnecting to a different server, unique ids won't
3645          * match anymore, so we disable serverino. This prevents
3646          * dentry revalidation to think the dentry are stale (ESTALE).
3647          */
3648         cifs_autodisable_serverino(cifs_sb);
3649         /*
3650          * Force the use of prefix path to support failover on DFS paths that
3651          * resolve to targets that have different prefix paths.
3652          */
3653         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3654         kfree(cifs_sb->prepath);
3655         cifs_sb->prepath = ctx->prepath;
3656         ctx->prepath = NULL;
3657         uuid_copy(&cifs_sb->dfs_mount_id, &mount_id);
3658
3659 out:
3660         free_xid(xid);
3661         cifs_try_adding_channels(cifs_sb, ses);
3662         return mount_setup_tlink(cifs_sb, ses, tcon);
3663
3664 error:
3665         kfree(ref_path);
3666         kfree(full_path);
3667         kfree(cifs_sb->origin_fullpath);
3668         dfs_cache_put_refsrv_sessions(&mount_id);
3669         mount_put_conns(cifs_sb, xid, server, ses, tcon);
3670         return rc;
3671 }
3672 #else
3673 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3674 {
3675         int rc = 0;
3676         unsigned int xid;
3677         struct cifs_ses *ses;
3678         struct cifs_tcon *tcon;
3679         struct TCP_Server_Info *server;
3680
3681         rc = mount_get_conns(ctx, cifs_sb, &xid, &server, &ses, &tcon);
3682         if (rc)
3683                 goto error;
3684
3685         if (tcon) {
3686                 rc = is_path_remote(cifs_sb, ctx, xid, server, tcon);
3687                 if (rc == -EREMOTE)
3688                         rc = -EOPNOTSUPP;
3689                 if (rc)
3690                         goto error;
3691         }
3692
3693         free_xid(xid);
3694
3695         return mount_setup_tlink(cifs_sb, ses, tcon);
3696
3697 error:
3698         mount_put_conns(cifs_sb, xid, server, ses, tcon);
3699         return rc;
3700 }
3701 #endif
3702
3703 /*
3704  * Issue a TREE_CONNECT request.
3705  */
3706 int
3707 CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
3708          const char *tree, struct cifs_tcon *tcon,
3709          const struct nls_table *nls_codepage)
3710 {
3711         struct smb_hdr *smb_buffer;
3712         struct smb_hdr *smb_buffer_response;
3713         TCONX_REQ *pSMB;
3714         TCONX_RSP *pSMBr;
3715         unsigned char *bcc_ptr;
3716         int rc = 0;
3717         int length;
3718         __u16 bytes_left, count;
3719
3720         if (ses == NULL)
3721                 return -EIO;
3722
3723         smb_buffer = cifs_buf_get();
3724         if (smb_buffer == NULL)
3725                 return -ENOMEM;
3726
3727         smb_buffer_response = smb_buffer;
3728
3729         header_assemble(smb_buffer, SMB_COM_TREE_CONNECT_ANDX,
3730                         NULL /*no tid */ , 4 /*wct */ );
3731
3732         smb_buffer->Mid = get_next_mid(ses->server);
3733         smb_buffer->Uid = ses->Suid;
3734         pSMB = (TCONX_REQ *) smb_buffer;
3735         pSMBr = (TCONX_RSP *) smb_buffer_response;
3736
3737         pSMB->AndXCommand = 0xFF;
3738         pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
3739         bcc_ptr = &pSMB->Password[0];
3740         if (tcon->pipe || (ses->server->sec_mode & SECMODE_USER)) {
3741                 pSMB->PasswordLength = cpu_to_le16(1);  /* minimum */
3742                 *bcc_ptr = 0; /* password is null byte */
3743                 bcc_ptr++;              /* skip password */
3744                 /* already aligned so no need to do it below */
3745         }
3746
3747         if (ses->server->sign)
3748                 smb_buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
3749
3750         if (ses->capabilities & CAP_STATUS32) {
3751                 smb_buffer->Flags2 |= SMBFLG2_ERR_STATUS;
3752         }
3753         if (ses->capabilities & CAP_DFS) {
3754                 smb_buffer->Flags2 |= SMBFLG2_DFS;
3755         }
3756         if (ses->capabilities & CAP_UNICODE) {
3757                 smb_buffer->Flags2 |= SMBFLG2_UNICODE;
3758                 length =
3759                     cifs_strtoUTF16((__le16 *) bcc_ptr, tree,
3760                         6 /* max utf8 char length in bytes */ *
3761                         (/* server len*/ + 256 /* share len */), nls_codepage);
3762                 bcc_ptr += 2 * length;  /* convert num 16 bit words to bytes */
3763                 bcc_ptr += 2;   /* skip trailing null */
3764         } else {                /* ASCII */
3765                 strcpy(bcc_ptr, tree);
3766                 bcc_ptr += strlen(tree) + 1;
3767         }
3768         strcpy(bcc_ptr, "?????");
3769         bcc_ptr += strlen("?????");
3770         bcc_ptr += 1;
3771         count = bcc_ptr - &pSMB->Password[0];
3772         be32_add_cpu(&pSMB->hdr.smb_buf_length, count);
3773         pSMB->ByteCount = cpu_to_le16(count);
3774
3775         rc = SendReceive(xid, ses, smb_buffer, smb_buffer_response, &length,
3776                          0);
3777
3778         /* above now done in SendReceive */
3779         if (rc == 0) {
3780                 bool is_unicode;
3781
3782                 tcon->tidStatus = CifsGood;
3783                 tcon->need_reconnect = false;
3784                 tcon->tid = smb_buffer_response->Tid;
3785                 bcc_ptr = pByteArea(smb_buffer_response);
3786                 bytes_left = get_bcc(smb_buffer_response);
3787                 length = strnlen(bcc_ptr, bytes_left - 2);
3788                 if (smb_buffer->Flags2 & SMBFLG2_UNICODE)
3789                         is_unicode = true;
3790                 else
3791                         is_unicode = false;
3792
3793
3794                 /* skip service field (NB: this field is always ASCII) */
3795                 if (length == 3) {
3796                         if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
3797                             (bcc_ptr[2] == 'C')) {
3798                                 cifs_dbg(FYI, "IPC connection\n");
3799                                 tcon->ipc = true;
3800                                 tcon->pipe = true;
3801                         }
3802                 } else if (length == 2) {
3803                         if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {
3804                                 /* the most common case */
3805                                 cifs_dbg(FYI, "disk share connection\n");
3806                         }
3807                 }
3808                 bcc_ptr += length + 1;
3809                 bytes_left -= (length + 1);
3810                 strlcpy(tcon->treeName, tree, sizeof(tcon->treeName));
3811
3812                 /* mostly informational -- no need to fail on error here */
3813                 kfree(tcon->nativeFileSystem);
3814                 tcon->nativeFileSystem = cifs_strndup_from_utf16(bcc_ptr,
3815                                                       bytes_left, is_unicode,
3816                                                       nls_codepage);
3817
3818                 cifs_dbg(FYI, "nativeFileSystem=%s\n", tcon->nativeFileSystem);
3819
3820                 if ((smb_buffer_response->WordCount == 3) ||
3821                          (smb_buffer_response->WordCount == 7))
3822                         /* field is in same location */
3823                         tcon->Flags = le16_to_cpu(pSMBr->OptionalSupport);
3824                 else
3825                         tcon->Flags = 0;
3826                 cifs_dbg(FYI, "Tcon flags: 0x%x\n", tcon->Flags);
3827         }
3828
3829         cifs_buf_release(smb_buffer);
3830         return rc;
3831 }
3832
3833 static void delayed_free(struct rcu_head *p)
3834 {
3835         struct cifs_sb_info *cifs_sb = container_of(p, struct cifs_sb_info, rcu);
3836
3837         unload_nls(cifs_sb->local_nls);
3838         smb3_cleanup_fs_context(cifs_sb->ctx);
3839         kfree(cifs_sb);
3840 }
3841
3842 void
3843 cifs_umount(struct cifs_sb_info *cifs_sb)
3844 {
3845         struct rb_root *root = &cifs_sb->tlink_tree;
3846         struct rb_node *node;
3847         struct tcon_link *tlink;
3848
3849         cancel_delayed_work_sync(&cifs_sb->prune_tlinks);
3850
3851         spin_lock(&cifs_sb->tlink_tree_lock);
3852         while ((node = rb_first(root))) {
3853                 tlink = rb_entry(node, struct tcon_link, tl_rbnode);
3854                 cifs_get_tlink(tlink);
3855                 clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3856                 rb_erase(node, root);
3857
3858                 spin_unlock(&cifs_sb->tlink_tree_lock);
3859                 cifs_put_tlink(tlink);
3860                 spin_lock(&cifs_sb->tlink_tree_lock);
3861         }
3862         spin_unlock(&cifs_sb->tlink_tree_lock);
3863
3864         kfree(cifs_sb->prepath);
3865 #ifdef CONFIG_CIFS_DFS_UPCALL
3866         dfs_cache_put_refsrv_sessions(&cifs_sb->dfs_mount_id);
3867         kfree(cifs_sb->origin_fullpath);
3868 #endif
3869         call_rcu(&cifs_sb->rcu, delayed_free);
3870 }
3871
3872 int
3873 cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses)
3874 {
3875         int rc = 0;
3876         struct TCP_Server_Info *server = cifs_ses_server(ses);
3877
3878         if (!server->ops->need_neg || !server->ops->negotiate)
3879                 return -ENOSYS;
3880
3881         /* only send once per connect */
3882         if (!server->ops->need_neg(server))
3883                 return 0;
3884
3885         rc = server->ops->negotiate(xid, ses);
3886         if (rc == 0) {
3887                 spin_lock(&GlobalMid_Lock);
3888                 if (server->tcpStatus == CifsNeedNegotiate)
3889                         server->tcpStatus = CifsGood;
3890                 else
3891                         rc = -EHOSTDOWN;
3892                 spin_unlock(&GlobalMid_Lock);
3893         }
3894
3895         return rc;
3896 }
3897
3898 int
3899 cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
3900                    struct nls_table *nls_info)
3901 {
3902         int rc = -ENOSYS;
3903         struct TCP_Server_Info *server = cifs_ses_server(ses);
3904
3905         if (!ses->binding) {
3906                 ses->capabilities = server->capabilities;
3907                 if (!linuxExtEnabled)
3908                         ses->capabilities &= (~server->vals->cap_unix);
3909
3910                 if (ses->auth_key.response) {
3911                         cifs_dbg(FYI, "Free previous auth_key.response = %p\n",
3912                                  ses->auth_key.response);
3913                         kfree(ses->auth_key.response);
3914                         ses->auth_key.response = NULL;
3915                         ses->auth_key.len = 0;
3916                 }
3917         }
3918
3919         cifs_dbg(FYI, "Security Mode: 0x%x Capabilities: 0x%x TimeAdjust: %d\n",
3920                  server->sec_mode, server->capabilities, server->timeAdj);
3921
3922         if (server->ops->sess_setup)
3923                 rc = server->ops->sess_setup(xid, ses, nls_info);
3924
3925         if (rc)
3926                 cifs_server_dbg(VFS, "Send error in SessSetup = %d\n", rc);
3927
3928         return rc;
3929 }
3930
3931 static int
3932 cifs_set_vol_auth(struct smb3_fs_context *ctx, struct cifs_ses *ses)
3933 {
3934         ctx->sectype = ses->sectype;
3935
3936         /* krb5 is special, since we don't need username or pw */
3937         if (ctx->sectype == Kerberos)
3938                 return 0;
3939
3940         return cifs_set_cifscreds(ctx, ses);
3941 }
3942
3943 static struct cifs_tcon *
3944 cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
3945 {
3946         int rc;
3947         struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
3948         struct cifs_ses *ses;
3949         struct cifs_tcon *tcon = NULL;
3950         struct smb3_fs_context *ctx;
3951
3952         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
3953         if (ctx == NULL)
3954                 return ERR_PTR(-ENOMEM);
3955
3956         ctx->local_nls = cifs_sb->local_nls;
3957         ctx->linux_uid = fsuid;
3958         ctx->cred_uid = fsuid;
3959         ctx->UNC = master_tcon->treeName;
3960         ctx->retry = master_tcon->retry;
3961         ctx->nocase = master_tcon->nocase;
3962         ctx->nohandlecache = master_tcon->nohandlecache;
3963         ctx->local_lease = master_tcon->local_lease;
3964         ctx->no_lease = master_tcon->no_lease;
3965         ctx->resilient = master_tcon->use_resilient;
3966         ctx->persistent = master_tcon->use_persistent;
3967         ctx->handle_timeout = master_tcon->handle_timeout;
3968         ctx->no_linux_ext = !master_tcon->unix_ext;
3969         ctx->linux_ext = master_tcon->posix_extensions;
3970         ctx->sectype = master_tcon->ses->sectype;
3971         ctx->sign = master_tcon->ses->sign;
3972         ctx->seal = master_tcon->seal;
3973         ctx->witness = master_tcon->use_witness;
3974
3975         rc = cifs_set_vol_auth(ctx, master_tcon->ses);
3976         if (rc) {
3977                 tcon = ERR_PTR(rc);
3978                 goto out;
3979         }
3980
3981         /* get a reference for the same TCP session */
3982         spin_lock(&cifs_tcp_ses_lock);
3983         ++master_tcon->ses->server->srv_count;
3984         spin_unlock(&cifs_tcp_ses_lock);
3985
3986         ses = cifs_get_smb_ses(master_tcon->ses->server, ctx);
3987         if (IS_ERR(ses)) {
3988                 tcon = (struct cifs_tcon *)ses;
3989                 cifs_put_tcp_session(master_tcon->ses->server, 0);
3990                 goto out;
3991         }
3992
3993         tcon = cifs_get_tcon(ses, ctx);
3994         if (IS_ERR(tcon)) {
3995                 cifs_put_smb_ses(ses);
3996                 goto out;
3997         }
3998
3999         if (cap_unix(ses))
4000                 reset_cifs_unix_caps(0, tcon, NULL, ctx);
4001
4002 out:
4003         kfree(ctx->username);
4004         kfree_sensitive(ctx->password);
4005         kfree(ctx);
4006
4007         return tcon;
4008 }
4009
4010 struct cifs_tcon *
4011 cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
4012 {
4013         return tlink_tcon(cifs_sb_master_tlink(cifs_sb));
4014 }
4015
4016 /* find and return a tlink with given uid */
4017 static struct tcon_link *
4018 tlink_rb_search(struct rb_root *root, kuid_t uid)
4019 {
4020         struct rb_node *node = root->rb_node;
4021         struct tcon_link *tlink;
4022
4023         while (node) {
4024                 tlink = rb_entry(node, struct tcon_link, tl_rbnode);
4025
4026                 if (uid_gt(tlink->tl_uid, uid))
4027                         node = node->rb_left;
4028                 else if (uid_lt(tlink->tl_uid, uid))
4029                         node = node->rb_right;
4030                 else
4031                         return tlink;
4032         }
4033         return NULL;
4034 }
4035
4036 /* insert a tcon_link into the tree */
4037 static void
4038 tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink)
4039 {
4040         struct rb_node **new = &(root->rb_node), *parent = NULL;
4041         struct tcon_link *tlink;
4042
4043         while (*new) {
4044                 tlink = rb_entry(*new, struct tcon_link, tl_rbnode);
4045                 parent = *new;
4046
4047                 if (uid_gt(tlink->tl_uid, new_tlink->tl_uid))
4048                         new = &((*new)->rb_left);
4049                 else
4050                         new = &((*new)->rb_right);
4051         }
4052
4053         rb_link_node(&new_tlink->tl_rbnode, parent, new);
4054         rb_insert_color(&new_tlink->tl_rbnode, root);
4055 }
4056
4057 /*
4058  * Find or construct an appropriate tcon given a cifs_sb and the fsuid of the
4059  * current task.
4060  *
4061  * If the superblock doesn't refer to a multiuser mount, then just return
4062  * the master tcon for the mount.
4063  *
4064  * First, search the rbtree for an existing tcon for this fsuid. If one
4065  * exists, then check to see if it's pending construction. If it is then wait
4066  * for construction to complete. Once it's no longer pending, check to see if
4067  * it failed and either return an error or retry construction, depending on
4068  * the timeout.
4069  *
4070  * If one doesn't exist then insert a new tcon_link struct into the tree and
4071  * try to construct a new one.
4072  */
4073 struct tcon_link *
4074 cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
4075 {
4076         int ret;
4077         kuid_t fsuid = current_fsuid();
4078         struct tcon_link *tlink, *newtlink;
4079
4080         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
4081                 return cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
4082
4083         spin_lock(&cifs_sb->tlink_tree_lock);
4084         tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4085         if (tlink)
4086                 cifs_get_tlink(tlink);
4087         spin_unlock(&cifs_sb->tlink_tree_lock);
4088
4089         if (tlink == NULL) {
4090                 newtlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
4091                 if (newtlink == NULL)
4092                         return ERR_PTR(-ENOMEM);
4093                 newtlink->tl_uid = fsuid;
4094                 newtlink->tl_tcon = ERR_PTR(-EACCES);
4095                 set_bit(TCON_LINK_PENDING, &newtlink->tl_flags);
4096                 set_bit(TCON_LINK_IN_TREE, &newtlink->tl_flags);
4097                 cifs_get_tlink(newtlink);
4098
4099                 spin_lock(&cifs_sb->tlink_tree_lock);
4100                 /* was one inserted after previous search? */
4101                 tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4102                 if (tlink) {
4103                         cifs_get_tlink(tlink);
4104                         spin_unlock(&cifs_sb->tlink_tree_lock);
4105                         kfree(newtlink);
4106                         goto wait_for_construction;
4107                 }
4108                 tlink = newtlink;
4109                 tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
4110                 spin_unlock(&cifs_sb->tlink_tree_lock);
4111         } else {
4112 wait_for_construction:
4113                 ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
4114                                   TASK_INTERRUPTIBLE);
4115                 if (ret) {
4116                         cifs_put_tlink(tlink);
4117                         return ERR_PTR(-ERESTARTSYS);
4118                 }
4119
4120                 /* if it's good, return it */
4121                 if (!IS_ERR(tlink->tl_tcon))
4122                         return tlink;
4123
4124                 /* return error if we tried this already recently */
4125                 if (time_before(jiffies, tlink->tl_time + TLINK_ERROR_EXPIRE)) {
4126                         cifs_put_tlink(tlink);
4127                         return ERR_PTR(-EACCES);
4128                 }
4129
4130                 if (test_and_set_bit(TCON_LINK_PENDING, &tlink->tl_flags))
4131                         goto wait_for_construction;
4132         }
4133
4134         tlink->tl_tcon = cifs_construct_tcon(cifs_sb, fsuid);
4135         clear_bit(TCON_LINK_PENDING, &tlink->tl_flags);
4136         wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING);
4137
4138         if (IS_ERR(tlink->tl_tcon)) {
4139                 cifs_put_tlink(tlink);
4140                 return ERR_PTR(-EACCES);
4141         }
4142
4143         return tlink;
4144 }
4145
4146 /*
4147  * periodic workqueue job that scans tcon_tree for a superblock and closes
4148  * out tcons.
4149  */
4150 static void
4151 cifs_prune_tlinks(struct work_struct *work)
4152 {
4153         struct cifs_sb_info *cifs_sb = container_of(work, struct cifs_sb_info,
4154                                                     prune_tlinks.work);
4155         struct rb_root *root = &cifs_sb->tlink_tree;
4156         struct rb_node *node;
4157         struct rb_node *tmp;
4158         struct tcon_link *tlink;
4159
4160         /*
4161          * Because we drop the spinlock in the loop in order to put the tlink
4162          * it's not guarded against removal of links from the tree. The only
4163          * places that remove entries from the tree are this function and
4164          * umounts. Because this function is non-reentrant and is canceled
4165          * before umount can proceed, this is safe.
4166          */
4167         spin_lock(&cifs_sb->tlink_tree_lock);
4168         node = rb_first(root);
4169         while (node != NULL) {
4170                 tmp = node;
4171                 node = rb_next(tmp);
4172                 tlink = rb_entry(tmp, struct tcon_link, tl_rbnode);
4173
4174                 if (test_bit(TCON_LINK_MASTER, &tlink->tl_flags) ||
4175                     atomic_read(&tlink->tl_count) != 0 ||
4176                     time_after(tlink->tl_time + TLINK_IDLE_EXPIRE, jiffies))
4177                         continue;
4178
4179                 cifs_get_tlink(tlink);
4180                 clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
4181                 rb_erase(tmp, root);
4182
4183                 spin_unlock(&cifs_sb->tlink_tree_lock);
4184                 cifs_put_tlink(tlink);
4185                 spin_lock(&cifs_sb->tlink_tree_lock);
4186         }
4187         spin_unlock(&cifs_sb->tlink_tree_lock);
4188
4189         queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
4190                                 TLINK_IDLE_EXPIRE);
4191 }
4192
4193 #ifdef CONFIG_CIFS_DFS_UPCALL
4194 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
4195 {
4196         int rc;
4197         struct TCP_Server_Info *server = tcon->ses->server;
4198         const struct smb_version_operations *ops = server->ops;
4199         struct dfs_cache_tgt_list tl;
4200         struct dfs_cache_tgt_iterator *it = NULL;
4201         char *tree;
4202         const char *tcp_host;
4203         size_t tcp_host_len;
4204         const char *dfs_host;
4205         size_t dfs_host_len;
4206         char *share = NULL, *prefix = NULL;
4207         struct dfs_info3_param ref = {0};
4208         bool isroot;
4209
4210         tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
4211         if (!tree)
4212                 return -ENOMEM;
4213
4214         /* If it is not dfs or there was no cached dfs referral, then reconnect to same share */
4215         if (!tcon->dfs_path || dfs_cache_noreq_find(tcon->dfs_path + 1, &ref, &tl)) {
4216                 if (tcon->ipc) {
4217                         scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
4218                         rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
4219                 } else {
4220                         rc = ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
4221                 }
4222                 goto out;
4223         }
4224
4225         isroot = ref.server_type == DFS_TYPE_ROOT;
4226         free_dfs_info_param(&ref);
4227
4228         extract_unc_hostname(server->hostname, &tcp_host, &tcp_host_len);
4229
4230         for (it = dfs_cache_get_tgt_iterator(&tl); it; it = dfs_cache_get_next_tgt(&tl, it)) {
4231                 bool target_match;
4232
4233                 kfree(share);
4234                 kfree(prefix);
4235                 share = NULL;
4236                 prefix = NULL;
4237
4238                 rc = dfs_cache_get_tgt_share(tcon->dfs_path + 1, it, &share, &prefix);
4239                 if (rc) {
4240                         cifs_dbg(VFS, "%s: failed to parse target share %d\n",
4241                                  __func__, rc);
4242                         continue;
4243                 }
4244
4245                 extract_unc_hostname(share, &dfs_host, &dfs_host_len);
4246
4247                 if (dfs_host_len != tcp_host_len
4248                     || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {
4249                         cifs_dbg(FYI, "%s: %.*s doesn't match %.*s\n", __func__, (int)dfs_host_len,
4250                                  dfs_host, (int)tcp_host_len, tcp_host);
4251
4252                         rc = match_target_ip(server, dfs_host, dfs_host_len, &target_match);
4253                         if (rc) {
4254                                 cifs_dbg(VFS, "%s: failed to match target ip: %d\n", __func__, rc);
4255                                 break;
4256                         }
4257
4258                         if (!target_match) {
4259                                 cifs_dbg(FYI, "%s: skipping target\n", __func__);
4260                                 continue;
4261                         }
4262                 }
4263
4264                 if (tcon->ipc) {
4265                         scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", share);
4266                         rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
4267                 } else {
4268                         scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
4269                         rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
4270                         /* Only handle prefix paths of DFS link targets */
4271                         if (!rc && !isroot) {
4272                                 rc = update_super_prepath(tcon, prefix);
4273                                 break;
4274                         }
4275                 }
4276                 if (rc == -EREMOTE)
4277                         break;
4278         }
4279
4280         kfree(share);
4281         kfree(prefix);
4282
4283         if (!rc) {
4284                 if (it)
4285                         rc = dfs_cache_noreq_update_tgthint(tcon->dfs_path + 1, it);
4286                 else
4287                         rc = -ENOENT;
4288         }
4289         dfs_cache_free_tgts(&tl);
4290 out:
4291         kfree(tree);
4292         return rc;
4293 }
4294 #else
4295 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
4296 {
4297         const struct smb_version_operations *ops = tcon->ses->server->ops;
4298
4299         return ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
4300 }
4301 #endif