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 struct mount_ctx {
  65         struct cifs_sb_info *cifs_sb;
  66         struct smb3_fs_context *fs_ctx;
  67         unsigned int xid;
  68         struct TCP_Server_Info *server;
  69         struct cifs_ses *ses;
  70         struct cifs_tcon *tcon;
  71 #ifdef CONFIG_CIFS_DFS_UPCALL
  72         struct cifs_ses *root_ses;
  73         uuid_t mount_id;
  74         char *origin_fullpath, *leaf_fullpath;
  75 #endif
  76 };
  77
  78 static int ip_connect(struct TCP_Server_Info *server);
  79 static int generic_ip_connect(struct TCP_Server_Info *server);
  80 static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
  81 static void cifs_prune_tlinks(struct work_struct *work);
  82
  83 /*
  84  * Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may
  85  * get their ip addresses changed at some point.
  86  *
  87  * This should be called with server->srv_mutex held.
  88  */
  89 static int reconn_set_ipaddr_from_hostname(struct TCP_Server_Info *server)
  90 {
  91         int rc;
  92         int len;
  93         char *unc, *ipaddr = NULL;
  94         time64_t expiry, now;
  95         unsigned long ttl = SMB_DNS_RESOLVE_INTERVAL_DEFAULT;
  96
  97         if (!server->hostname)
  98                 return -EINVAL;
  99
 100         /* if server hostname isn't populated, there's nothing to do here */
 101         if (server->hostname[0] == '\0')
 102                 return 0;
 103
 104         len = strlen(server->hostname) + 3;
 105
 106         unc = kmalloc(len, GFP_KERNEL);
 107         if (!unc) {
 108                 cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
 109                 return -ENOMEM;
 110         }
 111         scnprintf(unc, len, "\\\\%s", server->hostname);
 112
 113         rc = dns_resolve_server_name_to_ip(unc, &ipaddr, &expiry);
 114         kfree(unc);
 115
 116         if (rc < 0) {
 117                 cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",
 118                          __func__, server->hostname, rc);
 119                 goto requeue_resolve;
 120         }
 121
 122         spin_lock(&cifs_tcp_ses_lock);
 123         rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,
 124                                   strlen(ipaddr));
 125         spin_unlock(&cifs_tcp_ses_lock);
 126         kfree(ipaddr);
 127
 128         /* rc == 1 means success here */
 129         if (rc) {
 130                 now = ktime_get_real_seconds();
 131                 if (expiry && expiry > now)
 132                         /*
 133                          * To make sure we don't use the cached entry, retry 1s
 134                          * after expiry.
 135                          */
 136                         ttl = max_t(unsigned long, expiry - now, SMB_DNS_RESOLVE_INTERVAL_MIN) + 1;
 137         }
 138         rc = !rc ? -1 : 0;
 139
 140 requeue_resolve:
 141         cifs_dbg(FYI, "%s: next dns resolution scheduled for %lu seconds in the future\n",
 142                  __func__, ttl);
 143         mod_delayed_work(cifsiod_wq, &server->resolve, (ttl * HZ));
 144
 145         return rc;
 146 }
 147
 148 static void smb2_query_server_interfaces(struct work_struct *work)
 149 {
 150         int rc;
 151         struct cifs_tcon *tcon = container_of(work,
 152                                         struct cifs_tcon,
 153                                         query_interfaces.work);
 154
 155         /*
 156          * query server network interfaces, in case they change
 157          */
 158         rc = SMB3_request_interfaces(0, tcon);
 159         if (rc) {
 160                 cifs_dbg(FYI, "%s: failed to query server interfaces: %d\n",
 161                                 __func__, rc);
 162         }
 163
 164         queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
 165                            (SMB_INTERFACE_POLL_INTERVAL * HZ));
 166 }
 167
 168 static void cifs_resolve_server(struct work_struct *work)
 169 {
 170         int rc;
 171         struct TCP_Server_Info *server = container_of(work,
 172                                         struct TCP_Server_Info, resolve.work);
 173
 174         cifs_server_lock(server);
 175
 176         /*
 177          * Resolve the hostname again to make sure that IP address is up-to-date.
 178          */
 179         rc = reconn_set_ipaddr_from_hostname(server);
 180         if (rc) {
 181                 cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",
 182                                 __func__, rc);
 183         }
 184
 185         cifs_server_unlock(server);
 186 }
 187
 188 /*
 189  * Update the tcpStatus for the server.
 190  * This is used to signal the cifsd thread to call cifs_reconnect
 191  * ONLY cifsd thread should call cifs_reconnect. For any other
 192  * thread, use this function
 193  *
 194  * @server: the tcp ses for which reconnect is needed
 195  * @all_channels: if this needs to be done for all channels
 196  */
 197 void
 198 cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server,
 199                                 bool all_channels)
 200 {
 201         struct TCP_Server_Info *pserver;
 202         struct cifs_ses *ses;
 203         int i;
 204
 205         /* If server is a channel, select the primary channel */
 206         pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
 207
 208         spin_lock(&cifs_tcp_ses_lock);
 209         if (!all_channels) {
 210                 pserver->tcpStatus = CifsNeedReconnect;
 211                 spin_unlock(&cifs_tcp_ses_lock);
 212                 return;
 213         }
 214
 215         list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 216                 spin_lock(&ses->chan_lock);
 217                 for (i = 0; i < ses->chan_count; i++)
 218                         ses->chans[i].server->tcpStatus = CifsNeedReconnect;
 219                 spin_unlock(&ses->chan_lock);
 220         }
 221         spin_unlock(&cifs_tcp_ses_lock);
 222 }
 223
 224 /*
 225  * Mark all sessions and tcons for reconnect.
 226  * IMPORTANT: make sure that this gets called only from
 227  * cifsd thread. For any other thread, use
 228  * cifs_signal_cifsd_for_reconnect
 229  *
 230  * @server: the tcp ses for which reconnect is needed
 231  * @server needs to be previously set to CifsNeedReconnect.
 232  * @mark_smb_session: whether even sessions need to be marked
 233  */
 234 void
 235 cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
 236                                       bool mark_smb_session)
 237 {
 238         struct TCP_Server_Info *pserver;
 239         struct cifs_ses *ses, *nses;
 240         struct cifs_tcon *tcon;
 241
 242         /*
 243          * before reconnecting the tcp session, mark the smb session (uid) and the tid bad so they
 244          * are not used until reconnected.
 245          */
 246         cifs_dbg(FYI, "%s: marking necessary sessions and tcons for reconnect\n", __func__);
 247
 248         /* If server is a channel, select the primary channel */
 249         pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;
 250
 251
 252         spin_lock(&cifs_tcp_ses_lock);
 253         list_for_each_entry_safe(ses, nses, &pserver->smb_ses_list, smb_ses_list) {
 254                 /* check if iface is still active */
 255                 if (!cifs_chan_is_iface_active(ses, server)) {
 256                         /*
 257                          * HACK: drop the lock before calling
 258                          * cifs_chan_update_iface to avoid deadlock
 259                          */
 260                         ses->ses_count++;
 261                         spin_unlock(&cifs_tcp_ses_lock);
 262                         cifs_chan_update_iface(ses, server);
 263                         spin_lock(&cifs_tcp_ses_lock);
 264                         ses->ses_count--;
 265                 }
 266
 267                 spin_lock(&ses->chan_lock);
 268                 if (!mark_smb_session && cifs_chan_needs_reconnect(ses, server))
 269                         goto next_session;
 270
 271                 if (mark_smb_session)
 272                         CIFS_SET_ALL_CHANS_NEED_RECONNECT(ses);
 273                 else
 274                         cifs_chan_set_need_reconnect(ses, server);
 275
 276                 /* If all channels need reconnect, then tcon needs reconnect */
 277                 if (!mark_smb_session && !CIFS_ALL_CHANS_NEED_RECONNECT(ses))
 278                         goto next_session;
 279
 280                 ses->ses_status = SES_NEED_RECON;
 281
 282                 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 283                         tcon->need_reconnect = true;
 284                         tcon->status = TID_NEED_RECON;
 285                 }
 286                 if (ses->tcon_ipc)
 287                         ses->tcon_ipc->need_reconnect = true;
 288
 289 next_session:
 290                 spin_unlock(&ses->chan_lock);
 291         }
 292         spin_unlock(&cifs_tcp_ses_lock);
 293 }
 294
 295 static void
 296 cifs_abort_connection(struct TCP_Server_Info *server)
 297 {
 298         struct mid_q_entry *mid, *nmid;
 299         struct list_head retry_list;
 300
 301         server->maxBuf = 0;
 302         server->max_read = 0;
 303
 304         /* do not want to be sending data on a socket we are freeing */
 305         cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
 306         cifs_server_lock(server);
 307         if (server->ssocket) {
 308                 cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n", server->ssocket->state,
 309                          server->ssocket->flags);
 310                 kernel_sock_shutdown(server->ssocket, SHUT_WR);
 311                 cifs_dbg(FYI, "Post shutdown state: 0x%x Flags: 0x%lx\n", server->ssocket->state,
 312                          server->ssocket->flags);
 313                 sock_release(server->ssocket);
 314                 server->ssocket = NULL;
 315         }
 316         server->sequence_number = 0;
 317         server->session_estab = false;
 318         kfree(server->session_key.response);
 319         server->session_key.response = NULL;
 320         server->session_key.len = 0;
 321         server->lstrp = jiffies;
 322
 323         /* mark submitted MIDs for retry and issue callback */
 324         INIT_LIST_HEAD(&retry_list);
 325         cifs_dbg(FYI, "%s: moving mids to private list\n", __func__);
 326         spin_lock(&GlobalMid_Lock);
 327         list_for_each_entry_safe(mid, nmid, &server->pending_mid_q, qhead) {
 328                 kref_get(&mid->refcount);
 329                 if (mid->mid_state == MID_REQUEST_SUBMITTED)
 330                         mid->mid_state = MID_RETRY_NEEDED;
 331                 list_move(&mid->qhead, &retry_list);
 332                 mid->mid_flags |= MID_DELETED;
 333         }
 334         spin_unlock(&GlobalMid_Lock);
 335         cifs_server_unlock(server);
 336
 337         cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
 338         list_for_each_entry_safe(mid, nmid, &retry_list, qhead) {
 339                 list_del_init(&mid->qhead);
 340                 mid->callback(mid);
 341                 cifs_mid_q_entry_release(mid);
 342         }
 343
 344         if (cifs_rdma_enabled(server)) {
 345                 cifs_server_lock(server);
 346                 smbd_destroy(server);
 347                 cifs_server_unlock(server);
 348         }
 349 }
 350
 351 static bool cifs_tcp_ses_needs_reconnect(struct TCP_Server_Info *server, int num_targets)
 352 {
 353         spin_lock(&cifs_tcp_ses_lock);
 354         server->nr_targets = num_targets;
 355         if (server->tcpStatus == CifsExiting) {
 356                 /* the demux thread will exit normally next time through the loop */
 357                 spin_unlock(&cifs_tcp_ses_lock);
 358                 wake_up(&server->response_q);
 359                 return false;
 360         }
 361
 362         cifs_dbg(FYI, "Mark tcp session as need reconnect\n");
 363         trace_smb3_reconnect(server->CurrentMid, server->conn_id,
 364                              server->hostname);
 365         server->tcpStatus = CifsNeedReconnect;
 366
 367         spin_unlock(&cifs_tcp_ses_lock);
 368         return true;
 369 }
 370
 371 /*
 372  * cifs tcp session reconnection
 373  *
 374  * mark tcp session as reconnecting so temporarily locked
 375  * mark all smb sessions as reconnecting for tcp session
 376  * reconnect tcp session
 377  * wake up waiters on reconnection? - (not needed currently)
 378  *
 379  * if mark_smb_session is passed as true, unconditionally mark
 380  * the smb session (and tcon) for reconnect as well. This value
 381  * doesn't really matter for non-multichannel scenario.
 382  *
 383  */
 384 static int __cifs_reconnect(struct TCP_Server_Info *server,
 385                             bool mark_smb_session)
 386 {
 387         int rc = 0;
 388
 389         if (!cifs_tcp_ses_needs_reconnect(server, 1))
 390                 return 0;
 391
 392         cifs_mark_tcp_ses_conns_for_reconnect(server, mark_smb_session);
 393
 394         cifs_abort_connection(server);
 395
 396         do {
 397                 try_to_freeze();
 398                 cifs_server_lock(server);
 399
 400                 if (!cifs_swn_set_server_dstaddr(server)) {
 401                         /* resolve the hostname again to make sure that IP address is up-to-date */
 402                         rc = reconn_set_ipaddr_from_hostname(server);
 403                         cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
 404                 }
 405
 406                 if (cifs_rdma_enabled(server))
 407                         rc = smbd_reconnect(server);
 408                 else
 409                         rc = generic_ip_connect(server);
 410                 if (rc) {
 411                         cifs_server_unlock(server);
 412                         cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
 413                         msleep(3000);
 414                 } else {
 415                         atomic_inc(&tcpSesReconnectCount);
 416                         set_credits(server, 1);
 417                         spin_lock(&cifs_tcp_ses_lock);
 418                         if (server->tcpStatus != CifsExiting)
 419                                 server->tcpStatus = CifsNeedNegotiate;
 420                         spin_unlock(&cifs_tcp_ses_lock);
 421                         cifs_swn_reset_server_dstaddr(server);
 422                         cifs_server_unlock(server);
 423                         mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 424                 }
 425         } while (server->tcpStatus == CifsNeedReconnect);
 426
 427         spin_lock(&cifs_tcp_ses_lock);
 428         if (server->tcpStatus == CifsNeedNegotiate)
 429                 mod_delayed_work(cifsiod_wq, &server->echo, 0);
 430         spin_unlock(&cifs_tcp_ses_lock);
 431
 432         wake_up(&server->response_q);
 433         return rc;
 434 }
 435
 436 #ifdef CONFIG_CIFS_DFS_UPCALL
 437 static int __reconnect_target_unlocked(struct TCP_Server_Info *server, const char *target)
 438 {
 439         int rc;
 440         char *hostname;
 441
 442         if (!cifs_swn_set_server_dstaddr(server)) {
 443                 if (server->hostname != target) {
 444                         hostname = extract_hostname(target);
 445                         if (!IS_ERR(hostname)) {
 446                                 kfree(server->hostname);
 447                                 server->hostname = hostname;
 448                         } else {
 449                                 cifs_dbg(FYI, "%s: couldn't extract hostname or address from dfs target: %ld\n",
 450                                          __func__, PTR_ERR(hostname));
 451                                 cifs_dbg(FYI, "%s: default to last target server: %s\n", __func__,
 452                                          server->hostname);
 453                         }
 454                 }
 455                 /* resolve the hostname again to make sure that IP address is up-to-date. */
 456                 rc = reconn_set_ipaddr_from_hostname(server);
 457                 cifs_dbg(FYI, "%s: reconn_set_ipaddr_from_hostname: rc=%d\n", __func__, rc);
 458         }
 459         /* Reconnect the socket */
 460         if (cifs_rdma_enabled(server))
 461                 rc = smbd_reconnect(server);
 462         else
 463                 rc = generic_ip_connect(server);
 464
 465         return rc;
 466 }
 467
 468 static int reconnect_target_unlocked(struct TCP_Server_Info *server, struct dfs_cache_tgt_list *tl,
 469                                      struct dfs_cache_tgt_iterator **target_hint)
 470 {
 471         int rc;
 472         struct dfs_cache_tgt_iterator *tit;
 473
 474         *target_hint = NULL;
 475
 476         /* If dfs target list is empty, then reconnect to last server */
 477         tit = dfs_cache_get_tgt_iterator(tl);
 478         if (!tit)
 479                 return __reconnect_target_unlocked(server, server->hostname);
 480
 481         /* Otherwise, try every dfs target in @tl */
 482         for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
 483                 rc = __reconnect_target_unlocked(server, dfs_cache_get_tgt_name(tit));
 484                 if (!rc) {
 485                         *target_hint = tit;
 486                         break;
 487                 }
 488         }
 489         return rc;
 490 }
 491
 492 static int reconnect_dfs_server(struct TCP_Server_Info *server)
 493 {
 494         int rc = 0;
 495         const char *refpath = server->current_fullpath + 1;
 496         struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
 497         struct dfs_cache_tgt_iterator *target_hint = NULL;
 498         int num_targets = 0;
 499
 500         /*
 501          * Determine the number of dfs targets the referral path in @cifs_sb resolves to.
 502          *
 503          * smb2_reconnect() needs to know how long it should wait based upon the number of dfs
 504          * targets (server->nr_targets).  It's also possible that the cached referral was cleared
 505          * through /proc/fs/cifs/dfscache or the target list is empty due to server settings after
 506          * refreshing the referral, so, in this case, default it to 1.
 507          */
 508         if (!dfs_cache_noreq_find(refpath, NULL, &tl))
 509                 num_targets = dfs_cache_get_nr_tgts(&tl);
 510         if (!num_targets)
 511                 num_targets = 1;
 512
 513         if (!cifs_tcp_ses_needs_reconnect(server, num_targets))
 514                 return 0;
 515
 516         /*
 517          * Unconditionally mark all sessions & tcons for reconnect as we might be connecting to a
 518          * different server or share during failover.  It could be improved by adding some logic to
 519          * only do that in case it connects to a different server or share, though.
 520          */
 521         cifs_mark_tcp_ses_conns_for_reconnect(server, true);
 522
 523         cifs_abort_connection(server);
 524
 525         do {
 526                 try_to_freeze();
 527                 cifs_server_lock(server);
 528
 529                 rc = reconnect_target_unlocked(server, &tl, &target_hint);
 530                 if (rc) {
 531                         /* Failed to reconnect socket */
 532                         cifs_server_unlock(server);
 533                         cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
 534                         msleep(3000);
 535                         continue;
 536                 }
 537                 /*
 538                  * Socket was created.  Update tcp session status to CifsNeedNegotiate so that a
 539                  * process waiting for reconnect will know it needs to re-establish session and tcon
 540                  * through the reconnected target server.
 541                  */
 542                 atomic_inc(&tcpSesReconnectCount);
 543                 set_credits(server, 1);
 544                 spin_lock(&cifs_tcp_ses_lock);
 545                 if (server->tcpStatus != CifsExiting)
 546                         server->tcpStatus = CifsNeedNegotiate;
 547                 spin_unlock(&cifs_tcp_ses_lock);
 548                 cifs_swn_reset_server_dstaddr(server);
 549                 cifs_server_unlock(server);
 550                 mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 551         } while (server->tcpStatus == CifsNeedReconnect);
 552
 553         if (target_hint)
 554                 dfs_cache_noreq_update_tgthint(refpath, target_hint);
 555
 556         dfs_cache_free_tgts(&tl);
 557
 558         /* Need to set up echo worker again once connection has been established */
 559         spin_lock(&cifs_tcp_ses_lock);
 560         if (server->tcpStatus == CifsNeedNegotiate)
 561                 mod_delayed_work(cifsiod_wq, &server->echo, 0);
 562
 563         spin_unlock(&cifs_tcp_ses_lock);
 564
 565         wake_up(&server->response_q);
 566         return rc;
 567 }
 568
 569 int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
 570 {
 571         /* If tcp session is not an dfs connection, then reconnect to last target server */
 572         spin_lock(&cifs_tcp_ses_lock);
 573         if (!server->is_dfs_conn) {
 574                 spin_unlock(&cifs_tcp_ses_lock);
 575                 return __cifs_reconnect(server, mark_smb_session);
 576         }
 577         spin_unlock(&cifs_tcp_ses_lock);
 578
 579         mutex_lock(&server->refpath_lock);
 580         if (!server->origin_fullpath || !server->leaf_fullpath) {
 581                 mutex_unlock(&server->refpath_lock);
 582                 return __cifs_reconnect(server, mark_smb_session);
 583         }
 584         mutex_unlock(&server->refpath_lock);
 585
 586         return reconnect_dfs_server(server);
 587 }
 588 #else
 589 int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
 590 {
 591         return __cifs_reconnect(server, mark_smb_session);
 592 }
 593 #endif
 594
 595 static void
 596 cifs_echo_request(struct work_struct *work)
 597 {
 598         int rc;
 599         struct TCP_Server_Info *server = container_of(work,
 600                                         struct TCP_Server_Info, echo.work);
 601
 602         /*
 603          * We cannot send an echo if it is disabled.
 604          * Also, no need to ping if we got a response recently.
 605          */
 606
 607         if (server->tcpStatus == CifsNeedReconnect ||
 608             server->tcpStatus == CifsExiting ||
 609             server->tcpStatus == CifsNew ||
 610             (server->ops->can_echo && !server->ops->can_echo(server)) ||
 611             time_before(jiffies, server->lstrp + server->echo_interval - HZ))
 612                 goto requeue_echo;
 613
 614         rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
 615         if (rc)
 616                 cifs_dbg(FYI, "Unable to send echo request to server: %s\n",
 617                          server->hostname);
 618
 619         /* Check witness registrations */
 620         cifs_swn_check();
 621
 622 requeue_echo:
 623         queue_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
 624 }
 625
 626 static bool
 627 allocate_buffers(struct TCP_Server_Info *server)
 628 {
 629         if (!server->bigbuf) {
 630                 server->bigbuf = (char *)cifs_buf_get();
 631                 if (!server->bigbuf) {
 632                         cifs_server_dbg(VFS, "No memory for large SMB response\n");
 633                         msleep(3000);
 634                         /* retry will check if exiting */
 635                         return false;
 636                 }
 637         } else if (server->large_buf) {
 638                 /* we are reusing a dirty large buf, clear its start */
 639                 memset(server->bigbuf, 0, HEADER_SIZE(server));
 640         }
 641
 642         if (!server->smallbuf) {
 643                 server->smallbuf = (char *)cifs_small_buf_get();
 644                 if (!server->smallbuf) {
 645                         cifs_server_dbg(VFS, "No memory for SMB response\n");
 646                         msleep(1000);
 647                         /* retry will check if exiting */
 648                         return false;
 649                 }
 650                 /* beginning of smb buffer is cleared in our buf_get */
 651         } else {
 652                 /* if existing small buf clear beginning */
 653                 memset(server->smallbuf, 0, HEADER_SIZE(server));
 654         }
 655
 656         return true;
 657 }
 658
 659 static bool
 660 server_unresponsive(struct TCP_Server_Info *server)
 661 {
 662         /*
 663          * We need to wait 3 echo intervals to make sure we handle such
 664          * situations right:
 665          * 1s  client sends a normal SMB request
 666          * 2s  client gets a response
 667          * 30s echo workqueue job pops, and decides we got a response recently
 668          *     and don't need to send another
 669          * ...
 670          * 65s kernel_recvmsg times out, and we see that we haven't gotten
 671          *     a response in >60s.
 672          */
 673         spin_lock(&cifs_tcp_ses_lock);
 674         if ((server->tcpStatus == CifsGood ||
 675             server->tcpStatus == CifsNeedNegotiate) &&
 676             (!server->ops->can_echo || server->ops->can_echo(server)) &&
 677             time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
 678                 spin_unlock(&cifs_tcp_ses_lock);
 679                 cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
 680                          (3 * server->echo_interval) / HZ);
 681                 cifs_reconnect(server, false);
 682                 return true;
 683         }
 684         spin_unlock(&cifs_tcp_ses_lock);
 685
 686         return false;
 687 }
 688
 689 static inline bool
 690 zero_credits(struct TCP_Server_Info *server)
 691 {
 692         int val;
 693
 694         spin_lock(&server->req_lock);
 695         val = server->credits + server->echo_credits + server->oplock_credits;
 696         if (server->in_flight == 0 && val == 0) {
 697                 spin_unlock(&server->req_lock);
 698                 return true;
 699         }
 700         spin_unlock(&server->req_lock);
 701         return false;
 702 }
 703
 704 static int
 705 cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
 706 {
 707         int length = 0;
 708         int total_read;
 709
 710         smb_msg->msg_control = NULL;
 711         smb_msg->msg_controllen = 0;
 712
 713         for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
 714                 try_to_freeze();
 715
 716                 /* reconnect if no credits and no requests in flight */
 717                 if (zero_credits(server)) {
 718                         cifs_reconnect(server, false);
 719                         return -ECONNABORTED;
 720                 }
 721
 722                 if (server_unresponsive(server))
 723                         return -ECONNABORTED;
 724                 if (cifs_rdma_enabled(server) && server->smbd_conn)
 725                         length = smbd_recv(server->smbd_conn, smb_msg);
 726                 else
 727                         length = sock_recvmsg(server->ssocket, smb_msg, 0);
 728
 729                 spin_lock(&cifs_tcp_ses_lock);
 730                 if (server->tcpStatus == CifsExiting) {
 731                         spin_unlock(&cifs_tcp_ses_lock);
 732                         return -ESHUTDOWN;
 733                 }
 734
 735                 if (server->tcpStatus == CifsNeedReconnect) {
 736                         spin_unlock(&cifs_tcp_ses_lock);
 737                         cifs_reconnect(server, false);
 738                         return -ECONNABORTED;
 739                 }
 740                 spin_unlock(&cifs_tcp_ses_lock);
 741
 742                 if (length == -ERESTARTSYS ||
 743                     length == -EAGAIN ||
 744                     length == -EINTR) {
 745                         /*
 746                          * Minimum sleep to prevent looping, allowing socket
 747                          * to clear and app threads to set tcpStatus
 748                          * CifsNeedReconnect if server hung.
 749                          */
 750                         usleep_range(1000, 2000);
 751                         length = 0;
 752                         continue;
 753                 }
 754
 755                 if (length <= 0) {
 756                         cifs_dbg(FYI, "Received no data or error: %d\n", length);
 757                         cifs_reconnect(server, false);
 758                         return -ECONNABORTED;
 759                 }
 760         }
 761         return total_read;
 762 }
 763
 764 int
 765 cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
 766                       unsigned int to_read)
 767 {
 768         struct msghdr smb_msg;
 769         struct kvec iov = {.iov_base = buf, .iov_len = to_read};
 770         iov_iter_kvec(&smb_msg.msg_iter, READ, &iov, 1, to_read);
 771
 772         return cifs_readv_from_socket(server, &smb_msg);
 773 }
 774
 775 ssize_t
 776 cifs_discard_from_socket(struct TCP_Server_Info *server, size_t to_read)
 777 {
 778         struct msghdr smb_msg;
 779
 780         /*
 781          *  iov_iter_discard already sets smb_msg.type and count and iov_offset
 782          *  and cifs_readv_from_socket sets msg_control and msg_controllen
 783          *  so little to initialize in struct msghdr
 784          */
 785         smb_msg.msg_name = NULL;
 786         smb_msg.msg_namelen = 0;
 787         iov_iter_discard(&smb_msg.msg_iter, READ, to_read);
 788
 789         return cifs_readv_from_socket(server, &smb_msg);
 790 }
 791
 792 int
 793 cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
 794         unsigned int page_offset, unsigned int to_read)
 795 {
 796         struct msghdr smb_msg;
 797         struct bio_vec bv = {
 798                 .bv_page = page, .bv_len = to_read, .bv_offset = page_offset};
 799         iov_iter_bvec(&smb_msg.msg_iter, READ, &bv, 1, to_read);
 800         return cifs_readv_from_socket(server, &smb_msg);
 801 }
 802
 803 static bool
 804 is_smb_response(struct TCP_Server_Info *server, unsigned char type)
 805 {
 806         /*
 807          * The first byte big endian of the length field,
 808          * is actually not part of the length but the type
 809          * with the most common, zero, as regular data.
 810          */
 811         switch (type) {
 812         case RFC1002_SESSION_MESSAGE:
 813                 /* Regular SMB response */
 814                 return true;
 815         case RFC1002_SESSION_KEEP_ALIVE:
 816                 cifs_dbg(FYI, "RFC 1002 session keep alive\n");
 817                 break;
 818         case RFC1002_POSITIVE_SESSION_RESPONSE:
 819                 cifs_dbg(FYI, "RFC 1002 positive session response\n");
 820                 break;
 821         case RFC1002_NEGATIVE_SESSION_RESPONSE:
 822                 /*
 823                  * We get this from Windows 98 instead of an error on
 824                  * SMB negprot response.
 825                  */
 826                 cifs_dbg(FYI, "RFC 1002 negative session response\n");
 827                 /* give server a second to clean up */
 828                 msleep(1000);
 829                 /*
 830                  * Always try 445 first on reconnect since we get NACK
 831                  * on some if we ever connected to port 139 (the NACK
 832                  * is since we do not begin with RFC1001 session
 833                  * initialize frame).
 834                  */
 835                 cifs_set_port((struct sockaddr *)&server->dstaddr, CIFS_PORT);
 836                 cifs_reconnect(server, true);
 837                 break;
 838         default:
 839                 cifs_server_dbg(VFS, "RFC 1002 unknown response type 0x%x\n", type);
 840                 cifs_reconnect(server, true);
 841         }
 842
 843         return false;
 844 }
 845
 846 void
 847 dequeue_mid(struct mid_q_entry *mid, bool malformed)
 848 {
 849 #ifdef CONFIG_CIFS_STATS2
 850         mid->when_received = jiffies;
 851 #endif
 852         spin_lock(&GlobalMid_Lock);
 853         if (!malformed)
 854                 mid->mid_state = MID_RESPONSE_RECEIVED;
 855         else
 856                 mid->mid_state = MID_RESPONSE_MALFORMED;
 857         /*
 858          * Trying to handle/dequeue a mid after the send_recv()
 859          * function has finished processing it is a bug.
 860          */
 861         if (mid->mid_flags & MID_DELETED) {
 862                 spin_unlock(&GlobalMid_Lock);
 863                 pr_warn_once("trying to dequeue a deleted mid\n");
 864         } else {
 865                 list_del_init(&mid->qhead);
 866                 mid->mid_flags |= MID_DELETED;
 867                 spin_unlock(&GlobalMid_Lock);
 868         }
 869 }
 870
 871 static unsigned int
 872 smb2_get_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
 873 {
 874         struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
 875
 876         /*
 877          * SMB1 does not use credits.
 878          */
 879         if (server->vals->header_preamble_size)
 880                 return 0;
 881
 882         return le16_to_cpu(shdr->CreditRequest);
 883 }
 884
 885 static void
 886 handle_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 887            char *buf, int malformed)
 888 {
 889         if (server->ops->check_trans2 &&
 890             server->ops->check_trans2(mid, server, buf, malformed))
 891                 return;
 892         mid->credits_received = smb2_get_credits_from_hdr(buf, server);
 893         mid->resp_buf = buf;
 894         mid->large_buf = server->large_buf;
 895         /* Was previous buf put in mpx struct for multi-rsp? */
 896         if (!mid->multiRsp) {
 897                 /* smb buffer will be freed by user thread */
 898                 if (server->large_buf)
 899                         server->bigbuf = NULL;
 900                 else
 901                         server->smallbuf = NULL;
 902         }
 903         dequeue_mid(mid, malformed);
 904 }
 905
 906 static void clean_demultiplex_info(struct TCP_Server_Info *server)
 907 {
 908         int length;
 909
 910         /* take it off the list, if it's not already */
 911         spin_lock(&cifs_tcp_ses_lock);
 912         list_del_init(&server->tcp_ses_list);
 913         spin_unlock(&cifs_tcp_ses_lock);
 914
 915         cancel_delayed_work_sync(&server->echo);
 916         cancel_delayed_work_sync(&server->resolve);
 917
 918         spin_lock(&cifs_tcp_ses_lock);
 919         server->tcpStatus = CifsExiting;
 920         spin_unlock(&cifs_tcp_ses_lock);
 921         wake_up_all(&server->response_q);
 922
 923         /* check if we have blocked requests that need to free */
 924         spin_lock(&server->req_lock);
 925         if (server->credits <= 0)
 926                 server->credits = 1;
 927         spin_unlock(&server->req_lock);
 928         /*
 929          * Although there should not be any requests blocked on this queue it
 930          * can not hurt to be paranoid and try to wake up requests that may
 931          * haven been blocked when more than 50 at time were on the wire to the
 932          * same server - they now will see the session is in exit state and get
 933          * out of SendReceive.
 934          */
 935         wake_up_all(&server->request_q);
 936         /* give those requests time to exit */
 937         msleep(125);
 938         if (cifs_rdma_enabled(server))
 939                 smbd_destroy(server);
 940         if (server->ssocket) {
 941                 sock_release(server->ssocket);
 942                 server->ssocket = NULL;
 943         }
 944
 945         if (!list_empty(&server->pending_mid_q)) {
 946                 struct list_head dispose_list;
 947                 struct mid_q_entry *mid_entry;
 948                 struct list_head *tmp, *tmp2;
 949
 950                 INIT_LIST_HEAD(&dispose_list);
 951                 spin_lock(&GlobalMid_Lock);
 952                 list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
 953                         mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 954                         cifs_dbg(FYI, "Clearing mid %llu\n", mid_entry->mid);
 955                         kref_get(&mid_entry->refcount);
 956                         mid_entry->mid_state = MID_SHUTDOWN;
 957                         list_move(&mid_entry->qhead, &dispose_list);
 958                         mid_entry->mid_flags |= MID_DELETED;
 959                 }
 960                 spin_unlock(&GlobalMid_Lock);
 961
 962                 /* now walk dispose list and issue callbacks */
 963                 list_for_each_safe(tmp, tmp2, &dispose_list) {
 964                         mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
 965                         cifs_dbg(FYI, "Callback mid %llu\n", mid_entry->mid);
 966                         list_del_init(&mid_entry->qhead);
 967                         mid_entry->callback(mid_entry);
 968                         cifs_mid_q_entry_release(mid_entry);
 969                 }
 970                 /* 1/8th of sec is more than enough time for them to exit */
 971                 msleep(125);
 972         }
 973
 974         if (!list_empty(&server->pending_mid_q)) {
 975                 /*
 976                  * mpx threads have not exited yet give them at least the smb
 977                  * send timeout time for long ops.
 978                  *
 979                  * Due to delays on oplock break requests, we need to wait at
 980                  * least 45 seconds before giving up on a request getting a
 981                  * response and going ahead and killing cifsd.
 982                  */
 983                 cifs_dbg(FYI, "Wait for exit from demultiplex thread\n");
 984                 msleep(46000);
 985                 /*
 986                  * If threads still have not exited they are probably never
 987                  * coming home not much else we can do but free the memory.
 988                  */
 989         }
 990
 991 #ifdef CONFIG_CIFS_DFS_UPCALL
 992         kfree(server->origin_fullpath);
 993         kfree(server->leaf_fullpath);
 994 #endif
 995         kfree(server);
 996
 997         length = atomic_dec_return(&tcpSesAllocCount);
 998         if (length > 0)
 999                 mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
1000 }
1001
1002 static int
1003 standard_receive3(struct TCP_Server_Info *server, struct mid_q_entry *mid)
1004 {
1005         int length;
1006         char *buf = server->smallbuf;
1007         unsigned int pdu_length = server->pdu_size;
1008
1009         /* make sure this will fit in a large buffer */
1010         if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server) -
1011                 server->vals->header_preamble_size) {
1012                 cifs_server_dbg(VFS, "SMB response too long (%u bytes)\n", pdu_length);
1013                 cifs_reconnect(server, true);
1014                 return -ECONNABORTED;
1015         }
1016
1017         /* switch to large buffer if too big for a small one */
1018         if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
1019                 server->large_buf = true;
1020                 memcpy(server->bigbuf, buf, server->total_read);
1021                 buf = server->bigbuf;
1022         }
1023
1024         /* now read the rest */
1025         length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
1026                                        pdu_length - HEADER_SIZE(server) + 1
1027                                        + server->vals->header_preamble_size);
1028
1029         if (length < 0)
1030                 return length;
1031         server->total_read += length;
1032
1033         dump_smb(buf, server->total_read);
1034
1035         return cifs_handle_standard(server, mid);
1036 }
1037
1038 int
1039 cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
1040 {
1041         char *buf = server->large_buf ? server->bigbuf : server->smallbuf;
1042         int length;
1043
1044         /*
1045          * We know that we received enough to get to the MID as we
1046          * checked the pdu_length earlier. Now check to see
1047          * if the rest of the header is OK. We borrow the length
1048          * var for the rest of the loop to avoid a new stack var.
1049          *
1050          * 48 bytes is enough to display the header and a little bit
1051          * into the payload for debugging purposes.
1052          */
1053         length = server->ops->check_message(buf, server->total_read, server);
1054         if (length != 0)
1055                 cifs_dump_mem("Bad SMB: ", buf,
1056                         min_t(unsigned int, server->total_read, 48));
1057
1058         if (server->ops->is_session_expired &&
1059             server->ops->is_session_expired(buf)) {
1060                 cifs_reconnect(server, true);
1061                 return -1;
1062         }
1063
1064         if (server->ops->is_status_pending &&
1065             server->ops->is_status_pending(buf, server))
1066                 return -1;
1067
1068         if (!mid)
1069                 return length;
1070
1071         handle_mid(mid, server, buf, length);
1072         return 0;
1073 }
1074
1075 static void
1076 smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
1077 {
1078         struct smb2_hdr *shdr = (struct smb2_hdr *)buffer;
1079         int scredits, in_flight;
1080
1081         /*
1082          * SMB1 does not use credits.
1083          */
1084         if (server->vals->header_preamble_size)
1085                 return;
1086
1087         if (shdr->CreditRequest) {
1088                 spin_lock(&server->req_lock);
1089                 server->credits += le16_to_cpu(shdr->CreditRequest);
1090                 scredits = server->credits;
1091                 in_flight = server->in_flight;
1092                 spin_unlock(&server->req_lock);
1093                 wake_up(&server->request_q);
1094
1095                 trace_smb3_hdr_credits(server->CurrentMid,
1096                                 server->conn_id, server->hostname, scredits,
1097                                 le16_to_cpu(shdr->CreditRequest), in_flight);
1098                 cifs_server_dbg(FYI, "%s: added %u credits total=%d\n",
1099                                 __func__, le16_to_cpu(shdr->CreditRequest),
1100                                 scredits);
1101         }
1102 }
1103
1104
1105 static int
1106 cifs_demultiplex_thread(void *p)
1107 {
1108         int i, num_mids, length;
1109         struct TCP_Server_Info *server = p;
1110         unsigned int pdu_length;
1111         unsigned int next_offset;
1112         char *buf = NULL;
1113         struct task_struct *task_to_wake = NULL;
1114         struct mid_q_entry *mids[MAX_COMPOUND];
1115         char *bufs[MAX_COMPOUND];
1116         unsigned int noreclaim_flag, num_io_timeout = 0;
1117
1118         noreclaim_flag = memalloc_noreclaim_save();
1119         cifs_dbg(FYI, "Demultiplex PID: %d\n", task_pid_nr(current));
1120
1121         length = atomic_inc_return(&tcpSesAllocCount);
1122         if (length > 1)
1123                 mempool_resize(cifs_req_poolp, length + cifs_min_rcv);
1124
1125         set_freezable();
1126         allow_kernel_signal(SIGKILL);
1127         while (server->tcpStatus != CifsExiting) {
1128                 if (try_to_freeze())
1129                         continue;
1130
1131                 if (!allocate_buffers(server))
1132                         continue;
1133
1134                 server->large_buf = false;
1135                 buf = server->smallbuf;
1136                 pdu_length = 4; /* enough to get RFC1001 header */
1137
1138                 length = cifs_read_from_socket(server, buf, pdu_length);
1139                 if (length < 0)
1140                         continue;
1141
1142                 if (server->vals->header_preamble_size == 0)
1143                         server->total_read = 0;
1144                 else
1145                         server->total_read = length;
1146
1147                 /*
1148                  * The right amount was read from socket - 4 bytes,
1149                  * so we can now interpret the length field.
1150                  */
1151                 pdu_length = get_rfc1002_length(buf);
1152
1153                 cifs_dbg(FYI, "RFC1002 header 0x%x\n", pdu_length);
1154                 if (!is_smb_response(server, buf[0]))
1155                         continue;
1156 next_pdu:
1157                 server->pdu_size = pdu_length;
1158
1159                 /* make sure we have enough to get to the MID */
1160                 if (server->pdu_size < HEADER_SIZE(server) - 1 -
1161                     server->vals->header_preamble_size) {
1162                         cifs_server_dbg(VFS, "SMB response too short (%u bytes)\n",
1163                                  server->pdu_size);
1164                         cifs_reconnect(server, true);
1165                         continue;
1166                 }
1167
1168                 /* read down to the MID */
1169                 length = cifs_read_from_socket(server,
1170                              buf + server->vals->header_preamble_size,
1171                              HEADER_SIZE(server) - 1
1172                              - server->vals->header_preamble_size);
1173                 if (length < 0)
1174                         continue;
1175                 server->total_read += length;
1176
1177                 if (server->ops->next_header) {
1178                         next_offset = server->ops->next_header(buf);
1179                         if (next_offset)
1180                                 server->pdu_size = next_offset;
1181                 }
1182
1183                 memset(mids, 0, sizeof(mids));
1184                 memset(bufs, 0, sizeof(bufs));
1185                 num_mids = 0;
1186
1187                 if (server->ops->is_transform_hdr &&
1188                     server->ops->receive_transform &&
1189                     server->ops->is_transform_hdr(buf)) {
1190                         length = server->ops->receive_transform(server,
1191                                                                 mids,
1192                                                                 bufs,
1193                                                                 &num_mids);
1194                 } else {
1195                         mids[0] = server->ops->find_mid(server, buf);
1196                         bufs[0] = buf;
1197                         num_mids = 1;
1198
1199                         if (!mids[0] || !mids[0]->receive)
1200                                 length = standard_receive3(server, mids[0]);
1201                         else
1202                                 length = mids[0]->receive(server, mids[0]);
1203                 }
1204
1205                 if (length < 0) {
1206                         for (i = 0; i < num_mids; i++)
1207                                 if (mids[i])
1208                                         cifs_mid_q_entry_release(mids[i]);
1209                         continue;
1210                 }
1211
1212                 if (server->ops->is_status_io_timeout &&
1213                     server->ops->is_status_io_timeout(buf)) {
1214                         num_io_timeout++;
1215                         if (num_io_timeout > NUM_STATUS_IO_TIMEOUT) {
1216                                 cifs_reconnect(server, false);
1217                                 num_io_timeout = 0;
1218                                 continue;
1219                         }
1220                 }
1221
1222                 server->lstrp = jiffies;
1223
1224                 for (i = 0; i < num_mids; i++) {
1225                         if (mids[i] != NULL) {
1226                                 mids[i]->resp_buf_size = server->pdu_size;
1227
1228                                 if (bufs[i] && server->ops->is_network_name_deleted)
1229                                         server->ops->is_network_name_deleted(bufs[i],
1230                                                                         server);
1231
1232                                 if (!mids[i]->multiRsp || mids[i]->multiEnd)
1233                                         mids[i]->callback(mids[i]);
1234
1235                                 cifs_mid_q_entry_release(mids[i]);
1236                         } else if (server->ops->is_oplock_break &&
1237                                    server->ops->is_oplock_break(bufs[i],
1238                                                                 server)) {
1239                                 smb2_add_credits_from_hdr(bufs[i], server);
1240                                 cifs_dbg(FYI, "Received oplock break\n");
1241                         } else {
1242                                 cifs_server_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n",
1243                                                 atomic_read(&midCount));
1244                                 cifs_dump_mem("Received Data is: ", bufs[i],
1245                                               HEADER_SIZE(server));
1246                                 smb2_add_credits_from_hdr(bufs[i], server);
1247 #ifdef CONFIG_CIFS_DEBUG2
1248                                 if (server->ops->dump_detail)
1249                                         server->ops->dump_detail(bufs[i],
1250                                                                  server);
1251                                 cifs_dump_mids(server);
1252 #endif /* CIFS_DEBUG2 */
1253                         }
1254                 }
1255
1256                 if (pdu_length > server->pdu_size) {
1257                         if (!allocate_buffers(server))
1258                                 continue;
1259                         pdu_length -= server->pdu_size;
1260                         server->total_read = 0;
1261                         server->large_buf = false;
1262                         buf = server->smallbuf;
1263                         goto next_pdu;
1264                 }
1265         } /* end while !EXITING */
1266
1267         /* buffer usually freed in free_mid - need to free it here on exit */
1268         cifs_buf_release(server->bigbuf);
1269         if (server->smallbuf) /* no sense logging a debug message if NULL */
1270                 cifs_small_buf_release(server->smallbuf);
1271
1272         task_to_wake = xchg(&server->tsk, NULL);
1273         clean_demultiplex_info(server);
1274
1275         /* if server->tsk was NULL then wait for a signal before exiting */
1276         if (!task_to_wake) {
1277                 set_current_state(TASK_INTERRUPTIBLE);
1278                 while (!signal_pending(current)) {
1279                         schedule();
1280                         set_current_state(TASK_INTERRUPTIBLE);
1281                 }
1282                 set_current_state(TASK_RUNNING);
1283         }
1284
1285         memalloc_noreclaim_restore(noreclaim_flag);
1286         module_put_and_kthread_exit(0);
1287 }
1288
1289 /*
1290  * Returns true if srcaddr isn't specified and rhs isn't specified, or
1291  * if srcaddr is specified and matches the IP address of the rhs argument
1292  */
1293 bool
1294 cifs_match_ipaddr(struct sockaddr *srcaddr, struct sockaddr *rhs)
1295 {
1296         switch (srcaddr->sa_family) {
1297         case AF_UNSPEC:
1298                 return (rhs->sa_family == AF_UNSPEC);
1299         case AF_INET: {
1300                 struct sockaddr_in *saddr4 = (struct sockaddr_in *)srcaddr;
1301                 struct sockaddr_in *vaddr4 = (struct sockaddr_in *)rhs;
1302                 return (saddr4->sin_addr.s_addr == vaddr4->sin_addr.s_addr);
1303         }
1304         case AF_INET6: {
1305                 struct sockaddr_in6 *saddr6 = (struct sockaddr_in6 *)srcaddr;
1306                 struct sockaddr_in6 *vaddr6 = (struct sockaddr_in6 *)rhs;
1307                 return ipv6_addr_equal(&saddr6->sin6_addr, &vaddr6->sin6_addr);
1308         }
1309         default:
1310                 WARN_ON(1);
1311                 return false; /* don't expect to be here */
1312         }
1313 }
1314
1315 /*
1316  * If no port is specified in addr structure, we try to match with 445 port
1317  * and if it fails - with 139 ports. It should be called only if address
1318  * families of server and addr are equal.
1319  */
1320 static bool
1321 match_port(struct TCP_Server_Info *server, struct sockaddr *addr)
1322 {
1323         __be16 port, *sport;
1324
1325         /* SMBDirect manages its own ports, don't match it here */
1326         if (server->rdma)
1327                 return true;
1328
1329         switch (addr->sa_family) {
1330         case AF_INET:
1331                 sport = &((struct sockaddr_in *) &server->dstaddr)->sin_port;
1332                 port = ((struct sockaddr_in *) addr)->sin_port;
1333                 break;
1334         case AF_INET6:
1335                 sport = &((struct sockaddr_in6 *) &server->dstaddr)->sin6_port;
1336                 port = ((struct sockaddr_in6 *) addr)->sin6_port;
1337                 break;
1338         default:
1339                 WARN_ON(1);
1340                 return false;
1341         }
1342
1343         if (!port) {
1344                 port = htons(CIFS_PORT);
1345                 if (port == *sport)
1346                         return true;
1347
1348                 port = htons(RFC1001_PORT);
1349         }
1350
1351         return port == *sport;
1352 }
1353
1354 static bool
1355 match_address(struct TCP_Server_Info *server, struct sockaddr *addr,
1356               struct sockaddr *srcaddr)
1357 {
1358         switch (addr->sa_family) {
1359         case AF_INET: {
1360                 struct sockaddr_in *addr4 = (struct sockaddr_in *)addr;
1361                 struct sockaddr_in *srv_addr4 =
1362                                         (struct sockaddr_in *)&server->dstaddr;
1363
1364                 if (addr4->sin_addr.s_addr != srv_addr4->sin_addr.s_addr)
1365                         return false;
1366                 break;
1367         }
1368         case AF_INET6: {
1369                 struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)addr;
1370                 struct sockaddr_in6 *srv_addr6 =
1371                                         (struct sockaddr_in6 *)&server->dstaddr;
1372
1373                 if (!ipv6_addr_equal(&addr6->sin6_addr,
1374                                      &srv_addr6->sin6_addr))
1375                         return false;
1376                 if (addr6->sin6_scope_id != srv_addr6->sin6_scope_id)
1377                         return false;
1378                 break;
1379         }
1380         default:
1381                 WARN_ON(1);
1382                 return false; /* don't expect to be here */
1383         }
1384
1385         if (!cifs_match_ipaddr(srcaddr, (struct sockaddr *)&server->srcaddr))
1386                 return false;
1387
1388         return true;
1389 }
1390
1391 static bool
1392 match_security(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1393 {
1394         /*
1395          * The select_sectype function should either return the ctx->sectype
1396          * that was specified, or "Unspecified" if that sectype was not
1397          * compatible with the given NEGOTIATE request.
1398          */
1399         if (server->ops->select_sectype(server, ctx->sectype)
1400              == Unspecified)
1401                 return false;
1402
1403         /*
1404          * Now check if signing mode is acceptable. No need to check
1405          * global_secflags at this point since if MUST_SIGN is set then
1406          * the server->sign had better be too.
1407          */
1408         if (ctx->sign && !server->sign)
1409                 return false;
1410
1411         return true;
1412 }
1413
1414 static int match_server(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1415 {
1416         struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
1417
1418         if (ctx->nosharesock)
1419                 return 0;
1420
1421         /* this server does not share socket */
1422         if (server->nosharesock)
1423                 return 0;
1424
1425         /* If multidialect negotiation see if existing sessions match one */
1426         if (strcmp(ctx->vals->version_string, SMB3ANY_VERSION_STRING) == 0) {
1427                 if (server->vals->protocol_id < SMB30_PROT_ID)
1428                         return 0;
1429         } else if (strcmp(ctx->vals->version_string,
1430                    SMBDEFAULT_VERSION_STRING) == 0) {
1431                 if (server->vals->protocol_id < SMB21_PROT_ID)
1432                         return 0;
1433         } else if ((server->vals != ctx->vals) || (server->ops != ctx->ops))
1434                 return 0;
1435
1436         if (!net_eq(cifs_net_ns(server), current->nsproxy->net_ns))
1437                 return 0;
1438
1439         if (strcasecmp(server->hostname, ctx->server_hostname))
1440                 return 0;
1441
1442         if (!match_address(server, addr,
1443                            (struct sockaddr *)&ctx->srcaddr))
1444                 return 0;
1445
1446         if (!match_port(server, addr))
1447                 return 0;
1448
1449         if (!match_security(server, ctx))
1450                 return 0;
1451
1452         if (server->echo_interval != ctx->echo_interval * HZ)
1453                 return 0;
1454
1455         if (server->rdma != ctx->rdma)
1456                 return 0;
1457
1458         if (server->ignore_signature != ctx->ignore_signature)
1459                 return 0;
1460
1461         if (server->min_offload != ctx->min_offload)
1462                 return 0;
1463
1464         return 1;
1465 }
1466
1467 struct TCP_Server_Info *
1468 cifs_find_tcp_session(struct smb3_fs_context *ctx)
1469 {
1470         struct TCP_Server_Info *server;
1471
1472         spin_lock(&cifs_tcp_ses_lock);
1473         list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
1474 #ifdef CONFIG_CIFS_DFS_UPCALL
1475                 /*
1476                  * DFS failover implementation in cifs_reconnect() requires unique tcp sessions for
1477                  * DFS connections to do failover properly, so avoid sharing them with regular
1478                  * shares or even links that may connect to same server but having completely
1479                  * different failover targets.
1480                  */
1481                 if (server->is_dfs_conn)
1482                         continue;
1483 #endif
1484                 /*
1485                  * Skip ses channels since they're only handled in lower layers
1486                  * (e.g. cifs_send_recv).
1487                  */
1488                 if (CIFS_SERVER_IS_CHAN(server) || !match_server(server, ctx))
1489                         continue;
1490
1491                 ++server->srv_count;
1492                 spin_unlock(&cifs_tcp_ses_lock);
1493                 cifs_dbg(FYI, "Existing tcp session with server found\n");
1494                 return server;
1495         }
1496         spin_unlock(&cifs_tcp_ses_lock);
1497         return NULL;
1498 }
1499
1500 void
1501 cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
1502 {
1503         struct task_struct *task;
1504
1505         spin_lock(&cifs_tcp_ses_lock);
1506         if (--server->srv_count > 0) {
1507                 spin_unlock(&cifs_tcp_ses_lock);
1508                 return;
1509         }
1510
1511         /* srv_count can never go negative */
1512         WARN_ON(server->srv_count < 0);
1513
1514         put_net(cifs_net_ns(server));
1515
1516         list_del_init(&server->tcp_ses_list);
1517         spin_unlock(&cifs_tcp_ses_lock);
1518
1519         /* For secondary channels, we pick up ref-count on the primary server */
1520         if (CIFS_SERVER_IS_CHAN(server))
1521                 cifs_put_tcp_session(server->primary_server, from_reconnect);
1522
1523         cancel_delayed_work_sync(&server->echo);
1524         cancel_delayed_work_sync(&server->resolve);
1525
1526         if (from_reconnect)
1527                 /*
1528                  * Avoid deadlock here: reconnect work calls
1529                  * cifs_put_tcp_session() at its end. Need to be sure
1530                  * that reconnect work does nothing with server pointer after
1531                  * that step.
1532                  */
1533                 cancel_delayed_work(&server->reconnect);
1534         else
1535                 cancel_delayed_work_sync(&server->reconnect);
1536
1537         spin_lock(&cifs_tcp_ses_lock);
1538         server->tcpStatus = CifsExiting;
1539         spin_unlock(&cifs_tcp_ses_lock);
1540
1541         cifs_crypto_secmech_release(server);
1542
1543         kfree(server->session_key.response);
1544         server->session_key.response = NULL;
1545         server->session_key.len = 0;
1546         kfree(server->hostname);
1547
1548         task = xchg(&server->tsk, NULL);
1549         if (task)
1550                 send_sig(SIGKILL, task, 1);
1551 }
1552
1553 struct TCP_Server_Info *
1554 cifs_get_tcp_session(struct smb3_fs_context *ctx,
1555                      struct TCP_Server_Info *primary_server)
1556 {
1557         struct TCP_Server_Info *tcp_ses = NULL;
1558         int rc;
1559
1560         cifs_dbg(FYI, "UNC: %s\n", ctx->UNC);
1561
1562         /* see if we already have a matching tcp_ses */
1563         tcp_ses = cifs_find_tcp_session(ctx);
1564         if (tcp_ses)
1565                 return tcp_ses;
1566
1567         tcp_ses = kzalloc(sizeof(struct TCP_Server_Info), GFP_KERNEL);
1568         if (!tcp_ses) {
1569                 rc = -ENOMEM;
1570                 goto out_err;
1571         }
1572
1573         tcp_ses->hostname = kstrdup(ctx->server_hostname, GFP_KERNEL);
1574         if (!tcp_ses->hostname) {
1575                 rc = -ENOMEM;
1576                 goto out_err;
1577         }
1578
1579         if (ctx->nosharesock)
1580                 tcp_ses->nosharesock = true;
1581
1582         tcp_ses->ops = ctx->ops;
1583         tcp_ses->vals = ctx->vals;
1584         cifs_set_net_ns(tcp_ses, get_net(current->nsproxy->net_ns));
1585
1586         tcp_ses->conn_id = atomic_inc_return(&tcpSesNextId);
1587         tcp_ses->noblockcnt = ctx->rootfs;
1588         tcp_ses->noblocksnd = ctx->noblocksnd || ctx->rootfs;
1589         tcp_ses->noautotune = ctx->noautotune;
1590         tcp_ses->tcp_nodelay = ctx->sockopt_tcp_nodelay;
1591         tcp_ses->rdma = ctx->rdma;
1592         tcp_ses->in_flight = 0;
1593         tcp_ses->max_in_flight = 0;
1594         tcp_ses->credits = 1;
1595         if (primary_server) {
1596                 spin_lock(&cifs_tcp_ses_lock);
1597                 ++primary_server->srv_count;
1598                 tcp_ses->primary_server = primary_server;
1599                 spin_unlock(&cifs_tcp_ses_lock);
1600         }
1601         init_waitqueue_head(&tcp_ses->response_q);
1602         init_waitqueue_head(&tcp_ses->request_q);
1603         INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
1604         mutex_init(&tcp_ses->_srv_mutex);
1605         memcpy(tcp_ses->workstation_RFC1001_name,
1606                 ctx->source_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1607         memcpy(tcp_ses->server_RFC1001_name,
1608                 ctx->target_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
1609         tcp_ses->session_estab = false;
1610         tcp_ses->sequence_number = 0;
1611         tcp_ses->reconnect_instance = 1;
1612         tcp_ses->lstrp = jiffies;
1613         tcp_ses->compress_algorithm = cpu_to_le16(ctx->compression);
1614         spin_lock_init(&tcp_ses->req_lock);
1615         INIT_LIST_HEAD(&tcp_ses->tcp_ses_list);
1616         INIT_LIST_HEAD(&tcp_ses->smb_ses_list);
1617         INIT_DELAYED_WORK(&tcp_ses->echo, cifs_echo_request);
1618         INIT_DELAYED_WORK(&tcp_ses->resolve, cifs_resolve_server);
1619         INIT_DELAYED_WORK(&tcp_ses->reconnect, smb2_reconnect_server);
1620         mutex_init(&tcp_ses->reconnect_mutex);
1621 #ifdef CONFIG_CIFS_DFS_UPCALL
1622         mutex_init(&tcp_ses->refpath_lock);
1623 #endif
1624         memcpy(&tcp_ses->srcaddr, &ctx->srcaddr,
1625                sizeof(tcp_ses->srcaddr));
1626         memcpy(&tcp_ses->dstaddr, &ctx->dstaddr,
1627                 sizeof(tcp_ses->dstaddr));
1628         if (ctx->use_client_guid)
1629                 memcpy(tcp_ses->client_guid, ctx->client_guid,
1630                        SMB2_CLIENT_GUID_SIZE);
1631         else
1632                 generate_random_uuid(tcp_ses->client_guid);
1633         /*
1634          * at this point we are the only ones with the pointer
1635          * to the struct since the kernel thread not created yet
1636          * no need to spinlock this init of tcpStatus or srv_count
1637          */
1638         tcp_ses->tcpStatus = CifsNew;
1639         ++tcp_ses->srv_count;
1640
1641         if (ctx->echo_interval >= SMB_ECHO_INTERVAL_MIN &&
1642                 ctx->echo_interval <= SMB_ECHO_INTERVAL_MAX)
1643                 tcp_ses->echo_interval = ctx->echo_interval * HZ;
1644         else
1645                 tcp_ses->echo_interval = SMB_ECHO_INTERVAL_DEFAULT * HZ;
1646         if (tcp_ses->rdma) {
1647 #ifndef CONFIG_CIFS_SMB_DIRECT
1648                 cifs_dbg(VFS, "CONFIG_CIFS_SMB_DIRECT is not enabled\n");
1649                 rc = -ENOENT;
1650                 goto out_err_crypto_release;
1651 #endif
1652                 tcp_ses->smbd_conn = smbd_get_connection(
1653                         tcp_ses, (struct sockaddr *)&ctx->dstaddr);
1654                 if (tcp_ses->smbd_conn) {
1655                         cifs_dbg(VFS, "RDMA transport established\n");
1656                         rc = 0;
1657                         goto smbd_connected;
1658                 } else {
1659                         rc = -ENOENT;
1660                         goto out_err_crypto_release;
1661                 }
1662         }
1663         rc = ip_connect(tcp_ses);
1664         if (rc < 0) {
1665                 cifs_dbg(VFS, "Error connecting to socket. Aborting operation.\n");
1666                 goto out_err_crypto_release;
1667         }
1668 smbd_connected:
1669         /*
1670          * since we're in a cifs function already, we know that
1671          * this will succeed. No need for try_module_get().
1672          */
1673         __module_get(THIS_MODULE);
1674         tcp_ses->tsk = kthread_run(cifs_demultiplex_thread,
1675                                   tcp_ses, "cifsd");
1676         if (IS_ERR(tcp_ses->tsk)) {
1677                 rc = PTR_ERR(tcp_ses->tsk);
1678                 cifs_dbg(VFS, "error %d create cifsd thread\n", rc);
1679                 module_put(THIS_MODULE);
1680                 goto out_err_crypto_release;
1681         }
1682         tcp_ses->min_offload = ctx->min_offload;
1683         /*
1684          * at this point we are the only ones with the pointer
1685          * to the struct since the kernel thread not created yet
1686          * no need to spinlock this update of tcpStatus
1687          */
1688         spin_lock(&cifs_tcp_ses_lock);
1689         tcp_ses->tcpStatus = CifsNeedNegotiate;
1690         spin_unlock(&cifs_tcp_ses_lock);
1691
1692         if ((ctx->max_credits < 20) || (ctx->max_credits > 60000))
1693                 tcp_ses->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
1694         else
1695                 tcp_ses->max_credits = ctx->max_credits;
1696
1697         tcp_ses->nr_targets = 1;
1698         tcp_ses->ignore_signature = ctx->ignore_signature;
1699         /* thread spawned, put it on the list */
1700         spin_lock(&cifs_tcp_ses_lock);
1701         list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
1702         spin_unlock(&cifs_tcp_ses_lock);
1703
1704         /* queue echo request delayed work */
1705         queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
1706
1707         /* queue dns resolution delayed work */
1708         cifs_dbg(FYI, "%s: next dns resolution scheduled for %d seconds in the future\n",
1709                  __func__, SMB_DNS_RESOLVE_INTERVAL_DEFAULT);
1710
1711         queue_delayed_work(cifsiod_wq, &tcp_ses->resolve, (SMB_DNS_RESOLVE_INTERVAL_DEFAULT * HZ));
1712
1713         return tcp_ses;
1714
1715 out_err_crypto_release:
1716         cifs_crypto_secmech_release(tcp_ses);
1717
1718         put_net(cifs_net_ns(tcp_ses));
1719
1720 out_err:
1721         if (tcp_ses) {
1722                 if (CIFS_SERVER_IS_CHAN(tcp_ses))
1723                         cifs_put_tcp_session(tcp_ses->primary_server, false);
1724                 kfree(tcp_ses->hostname);
1725                 if (tcp_ses->ssocket)
1726                         sock_release(tcp_ses->ssocket);
1727                 kfree(tcp_ses);
1728         }
1729         return ERR_PTR(rc);
1730 }
1731
1732 static int match_session(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1733 {
1734         if (ctx->sectype != Unspecified &&
1735             ctx->sectype != ses->sectype)
1736                 return 0;
1737
1738         /*
1739          * If an existing session is limited to less channels than
1740          * requested, it should not be reused
1741          */
1742         spin_lock(&ses->chan_lock);
1743         if (ses->chan_max < ctx->max_channels) {
1744                 spin_unlock(&ses->chan_lock);
1745                 return 0;
1746         }
1747         spin_unlock(&ses->chan_lock);
1748
1749         switch (ses->sectype) {
1750         case Kerberos:
1751                 if (!uid_eq(ctx->cred_uid, ses->cred_uid))
1752                         return 0;
1753                 break;
1754         default:
1755                 /* NULL username means anonymous session */
1756                 if (ses->user_name == NULL) {
1757                         if (!ctx->nullauth)
1758                                 return 0;
1759                         break;
1760                 }
1761
1762                 /* anything else takes username/password */
1763                 if (strncmp(ses->user_name,
1764                             ctx->username ? ctx->username : "",
1765                             CIFS_MAX_USERNAME_LEN))
1766                         return 0;
1767                 if ((ctx->username && strlen(ctx->username) != 0) &&
1768                     ses->password != NULL &&
1769                     strncmp(ses->password,
1770                             ctx->password ? ctx->password : "",
1771                             CIFS_MAX_PASSWORD_LEN))
1772                         return 0;
1773         }
1774         return 1;
1775 }
1776
1777 /**
1778  * cifs_setup_ipc - helper to setup the IPC tcon for the session
1779  * @ses: smb session to issue the request on
1780  * @ctx: the superblock configuration context to use for building the
1781  *       new tree connection for the IPC (interprocess communication RPC)
1782  *
1783  * A new IPC connection is made and stored in the session
1784  * tcon_ipc. The IPC tcon has the same lifetime as the session.
1785  */
1786 static int
1787 cifs_setup_ipc(struct cifs_ses *ses, struct smb3_fs_context *ctx)
1788 {
1789         int rc = 0, xid;
1790         struct cifs_tcon *tcon;
1791         char unc[SERVER_NAME_LENGTH + sizeof("//x/IPC$")] = {0};
1792         bool seal = false;
1793         struct TCP_Server_Info *server = ses->server;
1794
1795         /*
1796          * If the mount request that resulted in the creation of the
1797          * session requires encryption, force IPC to be encrypted too.
1798          */
1799         if (ctx->seal) {
1800                 if (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)
1801                         seal = true;
1802                 else {
1803                         cifs_server_dbg(VFS,
1804                                  "IPC: server doesn't support encryption\n");
1805                         return -EOPNOTSUPP;
1806                 }
1807         }
1808
1809         tcon = tconInfoAlloc();
1810         if (tcon == NULL)
1811                 return -ENOMEM;
1812
1813         scnprintf(unc, sizeof(unc), "\\\\%s\\IPC$", server->hostname);
1814
1815         xid = get_xid();
1816         tcon->ses = ses;
1817         tcon->ipc = true;
1818         tcon->seal = seal;
1819         rc = server->ops->tree_connect(xid, ses, unc, tcon, ctx->local_nls);
1820         free_xid(xid);
1821
1822         if (rc) {
1823                 cifs_server_dbg(VFS, "failed to connect to IPC (rc=%d)\n", rc);
1824                 tconInfoFree(tcon);
1825                 goto out;
1826         }
1827
1828         cifs_dbg(FYI, "IPC tcon rc=%d ipc tid=0x%x\n", rc, tcon->tid);
1829
1830         ses->tcon_ipc = tcon;
1831 out:
1832         return rc;
1833 }
1834
1835 /**
1836  * cifs_free_ipc - helper to release the session IPC tcon
1837  * @ses: smb session to unmount the IPC from
1838  *
1839  * Needs to be called everytime a session is destroyed.
1840  *
1841  * On session close, the IPC is closed and the server must release all tcons of the session.
1842  * No need to send a tree disconnect here.
1843  *
1844  * Besides, it will make the server to not close durable and resilient files on session close, as
1845  * specified in MS-SMB2 3.3.5.6 Receiving an SMB2 LOGOFF Request.
1846  */
1847 static int
1848 cifs_free_ipc(struct cifs_ses *ses)
1849 {
1850         struct cifs_tcon *tcon = ses->tcon_ipc;
1851
1852         if (tcon == NULL)
1853                 return 0;
1854
1855         tconInfoFree(tcon);
1856         ses->tcon_ipc = NULL;
1857         return 0;
1858 }
1859
1860 static struct cifs_ses *
1861 cifs_find_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
1862 {
1863         struct cifs_ses *ses;
1864
1865         spin_lock(&cifs_tcp_ses_lock);
1866         list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
1867                 if (ses->ses_status == SES_EXITING)
1868                         continue;
1869                 if (!match_session(ses, ctx))
1870                         continue;
1871                 ++ses->ses_count;
1872                 spin_unlock(&cifs_tcp_ses_lock);
1873                 return ses;
1874         }
1875         spin_unlock(&cifs_tcp_ses_lock);
1876         return NULL;
1877 }
1878
1879 void cifs_put_smb_ses(struct cifs_ses *ses)
1880 {
1881         unsigned int rc, xid;
1882         unsigned int chan_count;
1883         struct TCP_Server_Info *server = ses->server;
1884
1885         spin_lock(&cifs_tcp_ses_lock);
1886         if (ses->ses_status == SES_EXITING) {
1887                 spin_unlock(&cifs_tcp_ses_lock);
1888                 return;
1889         }
1890
1891         cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
1892         cifs_dbg(FYI, "%s: ses ipc: %s\n", __func__, ses->tcon_ipc ? ses->tcon_ipc->treeName : "NONE");
1893
1894         if (--ses->ses_count > 0) {
1895                 spin_unlock(&cifs_tcp_ses_lock);
1896                 return;
1897         }
1898
1899         /* ses_count can never go negative */
1900         WARN_ON(ses->ses_count < 0);
1901
1902         if (ses->ses_status == SES_GOOD)
1903                 ses->ses_status = SES_EXITING;
1904         spin_unlock(&cifs_tcp_ses_lock);
1905
1906         cifs_free_ipc(ses);
1907
1908         if (ses->ses_status == SES_EXITING && server->ops->logoff) {
1909                 xid = get_xid();
1910                 rc = server->ops->logoff(xid, ses);
1911                 if (rc)
1912                         cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
1913                                 __func__, rc);
1914                 _free_xid(xid);
1915         }
1916
1917         spin_lock(&cifs_tcp_ses_lock);
1918         list_del_init(&ses->smb_ses_list);
1919         spin_unlock(&cifs_tcp_ses_lock);
1920
1921         spin_lock(&ses->chan_lock);
1922         chan_count = ses->chan_count;
1923
1924         /* close any extra channels */
1925         if (chan_count > 1) {
1926                 int i;
1927
1928                 for (i = 1; i < chan_count; i++) {
1929                         if (ses->chans[i].iface) {
1930                                 kref_put(&ses->chans[i].iface->refcount, release_iface);
1931                                 ses->chans[i].iface = NULL;
1932                         }
1933                         cifs_put_tcp_session(ses->chans[i].server, 0);
1934                         ses->chans[i].server = NULL;
1935                 }
1936         }
1937         spin_unlock(&ses->chan_lock);
1938
1939         sesInfoFree(ses);
1940         cifs_put_tcp_session(server, 0);
1941 }
1942
1943 #ifdef CONFIG_KEYS
1944
1945 /* strlen("cifs:a:") + CIFS_MAX_DOMAINNAME_LEN + 1 */
1946 #define CIFSCREDS_DESC_SIZE (7 + CIFS_MAX_DOMAINNAME_LEN + 1)
1947
1948 /* Populate username and pw fields from keyring if possible */
1949 static int
1950 cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
1951 {
1952         int rc = 0;
1953         int is_domain = 0;
1954         const char *delim, *payload;
1955         char *desc;
1956         ssize_t len;
1957         struct key *key;
1958         struct TCP_Server_Info *server = ses->server;
1959         struct sockaddr_in *sa;
1960         struct sockaddr_in6 *sa6;
1961         const struct user_key_payload *upayload;
1962
1963         desc = kmalloc(CIFSCREDS_DESC_SIZE, GFP_KERNEL);
1964         if (!desc)
1965                 return -ENOMEM;
1966
1967         /* try to find an address key first */
1968         switch (server->dstaddr.ss_family) {
1969         case AF_INET:
1970                 sa = (struct sockaddr_in *)&server->dstaddr;
1971                 sprintf(desc, "cifs:a:%pI4", &sa->sin_addr.s_addr);
1972                 break;
1973         case AF_INET6:
1974                 sa6 = (struct sockaddr_in6 *)&server->dstaddr;
1975                 sprintf(desc, "cifs:a:%pI6c", &sa6->sin6_addr.s6_addr);
1976                 break;
1977         default:
1978                 cifs_dbg(FYI, "Bad ss_family (%hu)\n",
1979                          server->dstaddr.ss_family);
1980                 rc = -EINVAL;
1981                 goto out_err;
1982         }
1983
1984         cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
1985         key = request_key(&key_type_logon, desc, "");
1986         if (IS_ERR(key)) {
1987                 if (!ses->domainName) {
1988                         cifs_dbg(FYI, "domainName is NULL\n");
1989                         rc = PTR_ERR(key);
1990                         goto out_err;
1991                 }
1992
1993                 /* didn't work, try to find a domain key */
1994                 sprintf(desc, "cifs:d:%s", ses->domainName);
1995                 cifs_dbg(FYI, "%s: desc=%s\n", __func__, desc);
1996                 key = request_key(&key_type_logon, desc, "");
1997                 if (IS_ERR(key)) {
1998                         rc = PTR_ERR(key);
1999                         goto out_err;
2000                 }
2001                 is_domain = 1;
2002         }
2003
2004         down_read(&key->sem);
2005         upayload = user_key_payload_locked(key);
2006         if (IS_ERR_OR_NULL(upayload)) {
2007                 rc = upayload ? PTR_ERR(upayload) : -EINVAL;
2008                 goto out_key_put;
2009         }
2010
2011         /* find first : in payload */
2012         payload = upayload->data;
2013         delim = strnchr(payload, upayload->datalen, ':');
2014         cifs_dbg(FYI, "payload=%s\n", payload);
2015         if (!delim) {
2016                 cifs_dbg(FYI, "Unable to find ':' in payload (datalen=%d)\n",
2017                          upayload->datalen);
2018                 rc = -EINVAL;
2019                 goto out_key_put;
2020         }
2021
2022         len = delim - payload;
2023         if (len > CIFS_MAX_USERNAME_LEN || len <= 0) {
2024                 cifs_dbg(FYI, "Bad value from username search (len=%zd)\n",
2025                          len);
2026                 rc = -EINVAL;
2027                 goto out_key_put;
2028         }
2029
2030         ctx->username = kstrndup(payload, len, GFP_KERNEL);
2031         if (!ctx->username) {
2032                 cifs_dbg(FYI, "Unable to allocate %zd bytes for username\n",
2033                          len);
2034                 rc = -ENOMEM;
2035                 goto out_key_put;
2036         }
2037         cifs_dbg(FYI, "%s: username=%s\n", __func__, ctx->username);
2038
2039         len = key->datalen - (len + 1);
2040         if (len > CIFS_MAX_PASSWORD_LEN || len <= 0) {
2041                 cifs_dbg(FYI, "Bad len for password search (len=%zd)\n", len);
2042                 rc = -EINVAL;
2043                 kfree(ctx->username);
2044                 ctx->username = NULL;
2045                 goto out_key_put;
2046         }
2047
2048         ++delim;
2049         ctx->password = kstrndup(delim, len, GFP_KERNEL);
2050         if (!ctx->password) {
2051                 cifs_dbg(FYI, "Unable to allocate %zd bytes for password\n",
2052                          len);
2053                 rc = -ENOMEM;
2054                 kfree(ctx->username);
2055                 ctx->username = NULL;
2056                 goto out_key_put;
2057         }
2058
2059         /*
2060          * If we have a domain key then we must set the domainName in the
2061          * for the request.
2062          */
2063         if (is_domain && ses->domainName) {
2064                 ctx->domainname = kstrdup(ses->domainName, GFP_KERNEL);
2065                 if (!ctx->domainname) {
2066                         cifs_dbg(FYI, "Unable to allocate %zd bytes for domain\n",
2067                                  len);
2068                         rc = -ENOMEM;
2069                         kfree(ctx->username);
2070                         ctx->username = NULL;
2071                         kfree_sensitive(ctx->password);
2072                         ctx->password = NULL;
2073                         goto out_key_put;
2074                 }
2075         }
2076
2077         strscpy(ctx->workstation_name, ses->workstation_name, sizeof(ctx->workstation_name));
2078
2079 out_key_put:
2080         up_read(&key->sem);
2081         key_put(key);
2082 out_err:
2083         kfree(desc);
2084         cifs_dbg(FYI, "%s: returning %d\n", __func__, rc);
2085         return rc;
2086 }
2087 #else /* ! CONFIG_KEYS */
2088 static inline int
2089 cifs_set_cifscreds(struct smb3_fs_context *ctx __attribute__((unused)),
2090                    struct cifs_ses *ses __attribute__((unused)))
2091 {
2092         return -ENOSYS;
2093 }
2094 #endif /* CONFIG_KEYS */
2095
2096 /**
2097  * cifs_get_smb_ses - get a session matching @ctx data from @server
2098  * @server: server to setup the session to
2099  * @ctx: superblock configuration context to use to setup the session
2100  *
2101  * This function assumes it is being called from cifs_mount() where we
2102  * already got a server reference (server refcount +1). See
2103  * cifs_get_tcon() for refcount explanations.
2104  */
2105 struct cifs_ses *
2106 cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
2107 {
2108         int rc = -ENOMEM;
2109         unsigned int xid;
2110         struct cifs_ses *ses;
2111         struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
2112         struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
2113
2114         xid = get_xid();
2115
2116         ses = cifs_find_smb_ses(server, ctx);
2117         if (ses) {
2118                 cifs_dbg(FYI, "Existing smb sess found (status=%d)\n",
2119                          ses->ses_status);
2120
2121                 spin_lock(&ses->chan_lock);
2122                 if (cifs_chan_needs_reconnect(ses, server)) {
2123                         spin_unlock(&ses->chan_lock);
2124                         cifs_dbg(FYI, "Session needs reconnect\n");
2125
2126                         mutex_lock(&ses->session_mutex);
2127                         rc = cifs_negotiate_protocol(xid, ses, server);
2128                         if (rc) {
2129                                 mutex_unlock(&ses->session_mutex);
2130                                 /* problem -- put our ses reference */
2131                                 cifs_put_smb_ses(ses);
2132                                 free_xid(xid);
2133                                 return ERR_PTR(rc);
2134                         }
2135
2136                         rc = cifs_setup_session(xid, ses, server,
2137                                                 ctx->local_nls);
2138                         if (rc) {
2139                                 mutex_unlock(&ses->session_mutex);
2140                                 /* problem -- put our reference */
2141                                 cifs_put_smb_ses(ses);
2142                                 free_xid(xid);
2143                                 return ERR_PTR(rc);
2144                         }
2145                         mutex_unlock(&ses->session_mutex);
2146
2147                         spin_lock(&ses->chan_lock);
2148                 }
2149                 spin_unlock(&ses->chan_lock);
2150
2151                 /* existing SMB ses has a server reference already */
2152                 cifs_put_tcp_session(server, 0);
2153                 free_xid(xid);
2154                 return ses;
2155         }
2156
2157         cifs_dbg(FYI, "Existing smb sess not found\n");
2158         ses = sesInfoAlloc();
2159         if (ses == NULL)
2160                 goto get_ses_fail;
2161
2162         /* new SMB session uses our server ref */
2163         ses->server = server;
2164         if (server->dstaddr.ss_family == AF_INET6)
2165                 sprintf(ses->ip_addr, "%pI6", &addr6->sin6_addr);
2166         else
2167                 sprintf(ses->ip_addr, "%pI4", &addr->sin_addr);
2168
2169         if (ctx->username) {
2170                 ses->user_name = kstrdup(ctx->username, GFP_KERNEL);
2171                 if (!ses->user_name)
2172                         goto get_ses_fail;
2173         }
2174
2175         /* ctx->password freed at unmount */
2176         if (ctx->password) {
2177                 ses->password = kstrdup(ctx->password, GFP_KERNEL);
2178                 if (!ses->password)
2179                         goto get_ses_fail;
2180         }
2181         if (ctx->domainname) {
2182                 ses->domainName = kstrdup(ctx->domainname, GFP_KERNEL);
2183                 if (!ses->domainName)
2184                         goto get_ses_fail;
2185         }
2186
2187         strscpy(ses->workstation_name, ctx->workstation_name, sizeof(ses->workstation_name));
2188
2189         if (ctx->domainauto)
2190                 ses->domainAuto = ctx->domainauto;
2191         ses->cred_uid = ctx->cred_uid;
2192         ses->linux_uid = ctx->linux_uid;
2193
2194         ses->sectype = ctx->sectype;
2195         ses->sign = ctx->sign;
2196
2197         /* add server as first channel */
2198         spin_lock(&ses->chan_lock);
2199         ses->chans[0].server = server;
2200         ses->chan_count = 1;
2201         ses->chan_max = ctx->multichannel ? ctx->max_channels:1;
2202         ses->chans_need_reconnect = 1;
2203         spin_unlock(&ses->chan_lock);
2204
2205         mutex_lock(&ses->session_mutex);
2206         rc = cifs_negotiate_protocol(xid, ses, server);
2207         if (!rc)
2208                 rc = cifs_setup_session(xid, ses, server, ctx->local_nls);
2209         mutex_unlock(&ses->session_mutex);
2210
2211         /* each channel uses a different signing key */
2212         spin_lock(&ses->chan_lock);
2213         memcpy(ses->chans[0].signkey, ses->smb3signingkey,
2214                sizeof(ses->smb3signingkey));
2215         spin_unlock(&ses->chan_lock);
2216
2217         if (rc)
2218                 goto get_ses_fail;
2219
2220         /*
2221          * success, put it on the list and add it as first channel
2222          * note: the session becomes active soon after this. So you'll
2223          * need to lock before changing something in the session.
2224          */
2225         spin_lock(&cifs_tcp_ses_lock);
2226         list_add(&ses->smb_ses_list, &server->smb_ses_list);
2227         spin_unlock(&cifs_tcp_ses_lock);
2228
2229         free_xid(xid);
2230
2231         cifs_setup_ipc(ses, ctx);
2232
2233         return ses;
2234
2235 get_ses_fail:
2236         sesInfoFree(ses);
2237         free_xid(xid);
2238         return ERR_PTR(rc);
2239 }
2240
2241 static int match_tcon(struct cifs_tcon *tcon, struct smb3_fs_context *ctx)
2242 {
2243         if (tcon->status == TID_EXITING)
2244                 return 0;
2245         if (strncmp(tcon->treeName, ctx->UNC, MAX_TREE_SIZE))
2246                 return 0;
2247         if (tcon->seal != ctx->seal)
2248                 return 0;
2249         if (tcon->snapshot_time != ctx->snapshot_time)
2250                 return 0;
2251         if (tcon->handle_timeout != ctx->handle_timeout)
2252                 return 0;
2253         if (tcon->no_lease != ctx->no_lease)
2254                 return 0;
2255         if (tcon->nodelete != ctx->nodelete)
2256                 return 0;
2257         return 1;
2258 }
2259
2260 static struct cifs_tcon *
2261 cifs_find_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2262 {
2263         struct list_head *tmp;
2264         struct cifs_tcon *tcon;
2265
2266         spin_lock(&cifs_tcp_ses_lock);
2267         list_for_each(tmp, &ses->tcon_list) {
2268                 tcon = list_entry(tmp, struct cifs_tcon, tcon_list);
2269
2270                 if (!match_tcon(tcon, ctx))
2271                         continue;
2272                 ++tcon->tc_count;
2273                 spin_unlock(&cifs_tcp_ses_lock);
2274                 return tcon;
2275         }
2276         spin_unlock(&cifs_tcp_ses_lock);
2277         return NULL;
2278 }
2279
2280 void
2281 cifs_put_tcon(struct cifs_tcon *tcon)
2282 {
2283         unsigned int xid;
2284         struct cifs_ses *ses;
2285
2286         /*
2287          * IPC tcon share the lifetime of their session and are
2288          * destroyed in the session put function
2289          */
2290         if (tcon == NULL || tcon->ipc)
2291                 return;
2292
2293         ses = tcon->ses;
2294         cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count);
2295         spin_lock(&cifs_tcp_ses_lock);
2296         if (--tcon->tc_count > 0) {
2297                 spin_unlock(&cifs_tcp_ses_lock);
2298                 return;
2299         }
2300
2301         /* tc_count can never go negative */
2302         WARN_ON(tcon->tc_count < 0);
2303
2304         list_del_init(&tcon->tcon_list);
2305         spin_unlock(&cifs_tcp_ses_lock);
2306
2307         /* cancel polling of interfaces */
2308         cancel_delayed_work_sync(&tcon->query_interfaces);
2309
2310         if (tcon->use_witness) {
2311                 int rc;
2312
2313                 rc = cifs_swn_unregister(tcon);
2314                 if (rc < 0) {
2315                         cifs_dbg(VFS, "%s: Failed to unregister for witness notifications: %d\n",
2316                                         __func__, rc);
2317                 }
2318         }
2319
2320         xid = get_xid();
2321         if (ses->server->ops->tree_disconnect)
2322                 ses->server->ops->tree_disconnect(xid, tcon);
2323         _free_xid(xid);
2324
2325         cifs_fscache_release_super_cookie(tcon);
2326         tconInfoFree(tcon);
2327         cifs_put_smb_ses(ses);
2328 }
2329
2330 /**
2331  * cifs_get_tcon - get a tcon matching @ctx data from @ses
2332  * @ses: smb session to issue the request on
2333  * @ctx: the superblock configuration context to use for building the
2334  *
2335  * - tcon refcount is the number of mount points using the tcon.
2336  * - ses refcount is the number of tcon using the session.
2337  *
2338  * 1. This function assumes it is being called from cifs_mount() where
2339  *    we already got a session reference (ses refcount +1).
2340  *
2341  * 2. Since we're in the context of adding a mount point, the end
2342  *    result should be either:
2343  *
2344  * a) a new tcon already allocated with refcount=1 (1 mount point) and
2345  *    its session refcount incremented (1 new tcon). This +1 was
2346  *    already done in (1).
2347  *
2348  * b) an existing tcon with refcount+1 (add a mount point to it) and
2349  *    identical ses refcount (no new tcon). Because of (1) we need to
2350  *    decrement the ses refcount.
2351  */
2352 static struct cifs_tcon *
2353 cifs_get_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
2354 {
2355         int rc, xid;
2356         struct cifs_tcon *tcon;
2357
2358         tcon = cifs_find_tcon(ses, ctx);
2359         if (tcon) {
2360                 /*
2361                  * tcon has refcount already incremented but we need to
2362                  * decrement extra ses reference gotten by caller (case b)
2363                  */
2364                 cifs_dbg(FYI, "Found match on UNC path\n");
2365                 cifs_put_smb_ses(ses);
2366                 return tcon;
2367         }
2368
2369         if (!ses->server->ops->tree_connect) {
2370                 rc = -ENOSYS;
2371                 goto out_fail;
2372         }
2373
2374         tcon = tconInfoAlloc();
2375         if (tcon == NULL) {
2376                 rc = -ENOMEM;
2377                 goto out_fail;
2378         }
2379
2380         if (ctx->snapshot_time) {
2381                 if (ses->server->vals->protocol_id == 0) {
2382                         cifs_dbg(VFS,
2383                              "Use SMB2 or later for snapshot mount option\n");
2384                         rc = -EOPNOTSUPP;
2385                         goto out_fail;
2386                 } else
2387                         tcon->snapshot_time = ctx->snapshot_time;
2388         }
2389
2390         if (ctx->handle_timeout) {
2391                 if (ses->server->vals->protocol_id == 0) {
2392                         cifs_dbg(VFS,
2393                              "Use SMB2.1 or later for handle timeout option\n");
2394                         rc = -EOPNOTSUPP;
2395                         goto out_fail;
2396                 } else
2397                         tcon->handle_timeout = ctx->handle_timeout;
2398         }
2399
2400         tcon->ses = ses;
2401         if (ctx->password) {
2402                 tcon->password = kstrdup(ctx->password, GFP_KERNEL);
2403                 if (!tcon->password) {
2404                         rc = -ENOMEM;
2405                         goto out_fail;
2406                 }
2407         }
2408
2409         if (ctx->seal) {
2410                 if (ses->server->vals->protocol_id == 0) {
2411                         cifs_dbg(VFS,
2412                                  "SMB3 or later required for encryption\n");
2413                         rc = -EOPNOTSUPP;
2414                         goto out_fail;
2415                 } else if (tcon->ses->server->capabilities &
2416                                         SMB2_GLOBAL_CAP_ENCRYPTION)
2417                         tcon->seal = true;
2418                 else {
2419                         cifs_dbg(VFS, "Encryption is not supported on share\n");
2420                         rc = -EOPNOTSUPP;
2421                         goto out_fail;
2422                 }
2423         }
2424
2425         if (ctx->linux_ext) {
2426                 if (ses->server->posix_ext_supported) {
2427                         tcon->posix_extensions = true;
2428                         pr_warn_once("SMB3.11 POSIX Extensions are experimental\n");
2429                 } else if ((ses->server->vals->protocol_id == SMB311_PROT_ID) ||
2430                     (strcmp(ses->server->vals->version_string,
2431                      SMB3ANY_VERSION_STRING) == 0) ||
2432                     (strcmp(ses->server->vals->version_string,
2433                      SMBDEFAULT_VERSION_STRING) == 0)) {
2434                         cifs_dbg(VFS, "Server does not support mounting with posix SMB3.11 extensions\n");
2435                         rc = -EOPNOTSUPP;
2436                         goto out_fail;
2437                 } else {
2438                         cifs_dbg(VFS, "Check vers= mount option. SMB3.11 "
2439                                 "disabled but required for POSIX extensions\n");
2440                         rc = -EOPNOTSUPP;
2441                         goto out_fail;
2442                 }
2443         }
2444
2445         xid = get_xid();
2446         rc = ses->server->ops->tree_connect(xid, ses, ctx->UNC, tcon,
2447                                             ctx->local_nls);
2448         free_xid(xid);
2449         cifs_dbg(FYI, "Tcon rc = %d\n", rc);
2450         if (rc)
2451                 goto out_fail;
2452
2453         tcon->use_persistent = false;
2454         /* check if SMB2 or later, CIFS does not support persistent handles */
2455         if (ctx->persistent) {
2456                 if (ses->server->vals->protocol_id == 0) {
2457                         cifs_dbg(VFS,
2458                              "SMB3 or later required for persistent handles\n");
2459                         rc = -EOPNOTSUPP;
2460                         goto out_fail;
2461                 } else if (ses->server->capabilities &
2462                            SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2463                         tcon->use_persistent = true;
2464                 else /* persistent handles requested but not supported */ {
2465                         cifs_dbg(VFS,
2466                                 "Persistent handles not supported on share\n");
2467                         rc = -EOPNOTSUPP;
2468                         goto out_fail;
2469                 }
2470         } else if ((tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
2471              && (ses->server->capabilities & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
2472              && (ctx->nopersistent == false)) {
2473                 cifs_dbg(FYI, "enabling persistent handles\n");
2474                 tcon->use_persistent = true;
2475         } else if (ctx->resilient) {
2476                 if (ses->server->vals->protocol_id == 0) {
2477                         cifs_dbg(VFS,
2478                              "SMB2.1 or later required for resilient handles\n");
2479                         rc = -EOPNOTSUPP;
2480                         goto out_fail;
2481                 }
2482                 tcon->use_resilient = true;
2483         }
2484
2485         tcon->use_witness = false;
2486         if (IS_ENABLED(CONFIG_CIFS_SWN_UPCALL) && ctx->witness) {
2487                 if (ses->server->vals->protocol_id >= SMB30_PROT_ID) {
2488                         if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER) {
2489                                 /*
2490                                  * Set witness in use flag in first place
2491                                  * to retry registration in the echo task
2492                                  */
2493                                 tcon->use_witness = true;
2494                                 /* And try to register immediately */
2495                                 rc = cifs_swn_register(tcon);
2496                                 if (rc < 0) {
2497                                         cifs_dbg(VFS, "Failed to register for witness notifications: %d\n", rc);
2498                                         goto out_fail;
2499                                 }
2500                         } else {
2501                                 /* TODO: try to extend for non-cluster uses (eg multichannel) */
2502                                 cifs_dbg(VFS, "witness requested on mount but no CLUSTER capability on share\n");
2503                                 rc = -EOPNOTSUPP;
2504                                 goto out_fail;
2505                         }
2506                 } else {
2507                         cifs_dbg(VFS, "SMB3 or later required for witness option\n");
2508                         rc = -EOPNOTSUPP;
2509                         goto out_fail;
2510                 }
2511         }
2512
2513         /* If the user really knows what they are doing they can override */
2514         if (tcon->share_flags & SMB2_SHAREFLAG_NO_CACHING) {
2515                 if (ctx->cache_ro)
2516                         cifs_dbg(VFS, "cache=ro requested on mount but NO_CACHING flag set on share\n");
2517                 else if (ctx->cache_rw)
2518                         cifs_dbg(VFS, "cache=singleclient requested on mount but NO_CACHING flag set on share\n");
2519         }
2520
2521         if (ctx->no_lease) {
2522                 if (ses->server->vals->protocol_id == 0) {
2523                         cifs_dbg(VFS,
2524                                 "SMB2 or later required for nolease option\n");
2525                         rc = -EOPNOTSUPP;
2526                         goto out_fail;
2527                 } else
2528                         tcon->no_lease = ctx->no_lease;
2529         }
2530
2531         /*
2532          * We can have only one retry value for a connection to a share so for
2533          * resources mounted more than once to the same server share the last
2534          * value passed in for the retry flag is used.
2535          */
2536         tcon->retry = ctx->retry;
2537         tcon->nocase = ctx->nocase;
2538         tcon->broken_sparse_sup = ctx->no_sparse;
2539         if (ses->server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING)
2540                 tcon->nohandlecache = ctx->nohandlecache;
2541         else
2542                 tcon->nohandlecache = true;
2543         tcon->nodelete = ctx->nodelete;
2544         tcon->local_lease = ctx->local_lease;
2545         INIT_LIST_HEAD(&tcon->pending_opens);
2546
2547         /* schedule query interfaces poll */
2548         INIT_DELAYED_WORK(&tcon->query_interfaces,
2549                           smb2_query_server_interfaces);
2550         queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
2551                            (SMB_INTERFACE_POLL_INTERVAL * HZ));
2552
2553         spin_lock(&cifs_tcp_ses_lock);
2554         list_add(&tcon->tcon_list, &ses->tcon_list);
2555         spin_unlock(&cifs_tcp_ses_lock);
2556
2557         return tcon;
2558
2559 out_fail:
2560         tconInfoFree(tcon);
2561         return ERR_PTR(rc);
2562 }
2563
2564 void
2565 cifs_put_tlink(struct tcon_link *tlink)
2566 {
2567         if (!tlink || IS_ERR(tlink))
2568                 return;
2569
2570         if (!atomic_dec_and_test(&tlink->tl_count) ||
2571             test_bit(TCON_LINK_IN_TREE, &tlink->tl_flags)) {
2572                 tlink->tl_time = jiffies;
2573                 return;
2574         }
2575
2576         if (!IS_ERR(tlink_tcon(tlink)))
2577                 cifs_put_tcon(tlink_tcon(tlink));
2578         kfree(tlink);
2579         return;
2580 }
2581
2582 static int
2583 compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
2584 {
2585         struct cifs_sb_info *old = CIFS_SB(sb);
2586         struct cifs_sb_info *new = mnt_data->cifs_sb;
2587         unsigned int oldflags = old->mnt_cifs_flags & CIFS_MOUNT_MASK;
2588         unsigned int newflags = new->mnt_cifs_flags & CIFS_MOUNT_MASK;
2589
2590         if ((sb->s_flags & CIFS_MS_MASK) != (mnt_data->flags & CIFS_MS_MASK))
2591                 return 0;
2592
2593         if (old->mnt_cifs_serverino_autodisabled)
2594                 newflags &= ~CIFS_MOUNT_SERVER_INUM;
2595
2596         if (oldflags != newflags)
2597                 return 0;
2598
2599         /*
2600          * We want to share sb only if we don't specify an r/wsize or
2601          * specified r/wsize is greater than or equal to existing one.
2602          */
2603         if (new->ctx->wsize && new->ctx->wsize < old->ctx->wsize)
2604                 return 0;
2605
2606         if (new->ctx->rsize && new->ctx->rsize < old->ctx->rsize)
2607                 return 0;
2608
2609         if (!uid_eq(old->ctx->linux_uid, new->ctx->linux_uid) ||
2610             !gid_eq(old->ctx->linux_gid, new->ctx->linux_gid))
2611                 return 0;
2612
2613         if (old->ctx->file_mode != new->ctx->file_mode ||
2614             old->ctx->dir_mode != new->ctx->dir_mode)
2615                 return 0;
2616
2617         if (strcmp(old->local_nls->charset, new->local_nls->charset))
2618                 return 0;
2619
2620         if (old->ctx->acregmax != new->ctx->acregmax)
2621                 return 0;
2622         if (old->ctx->acdirmax != new->ctx->acdirmax)
2623                 return 0;
2624
2625         return 1;
2626 }
2627
2628 static int
2629 match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
2630 {
2631         struct cifs_sb_info *old = CIFS_SB(sb);
2632         struct cifs_sb_info *new = mnt_data->cifs_sb;
2633         bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2634                 old->prepath;
2635         bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
2636                 new->prepath;
2637
2638         if (old_set && new_set && !strcmp(new->prepath, old->prepath))
2639                 return 1;
2640         else if (!old_set && !new_set)
2641                 return 1;
2642
2643         return 0;
2644 }
2645
2646 int
2647 cifs_match_super(struct super_block *sb, void *data)
2648 {
2649         struct cifs_mnt_data *mnt_data = (struct cifs_mnt_data *)data;
2650         struct smb3_fs_context *ctx;
2651         struct cifs_sb_info *cifs_sb;
2652         struct TCP_Server_Info *tcp_srv;
2653         struct cifs_ses *ses;
2654         struct cifs_tcon *tcon;
2655         struct tcon_link *tlink;
2656         int rc = 0;
2657
2658         spin_lock(&cifs_tcp_ses_lock);
2659         cifs_sb = CIFS_SB(sb);
2660         tlink = cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
2661         if (tlink == NULL) {
2662                 /* can not match superblock if tlink were ever null */
2663                 spin_unlock(&cifs_tcp_ses_lock);
2664                 return 0;
2665         }
2666         tcon = tlink_tcon(tlink);
2667         ses = tcon->ses;
2668         tcp_srv = ses->server;
2669
2670         ctx = mnt_data->ctx;
2671
2672         if (!match_server(tcp_srv, ctx) ||
2673             !match_session(ses, ctx) ||
2674             !match_tcon(tcon, ctx) ||
2675             !match_prepath(sb, mnt_data)) {
2676                 rc = 0;
2677                 goto out;
2678         }
2679
2680         rc = compare_mount_options(sb, mnt_data);
2681 out:
2682         spin_unlock(&cifs_tcp_ses_lock);
2683         cifs_put_tlink(tlink);
2684         return rc;
2685 }
2686
2687 #ifdef CONFIG_DEBUG_LOCK_ALLOC
2688 static struct lock_class_key cifs_key[2];
2689 static struct lock_class_key cifs_slock_key[2];
2690
2691 static inline void
2692 cifs_reclassify_socket4(struct socket *sock)
2693 {
2694         struct sock *sk = sock->sk;
2695         BUG_ON(!sock_allow_reclassification(sk));
2696         sock_lock_init_class_and_name(sk, "slock-AF_INET-CIFS",
2697                 &cifs_slock_key[0], "sk_lock-AF_INET-CIFS", &cifs_key[0]);
2698 }
2699
2700 static inline void
2701 cifs_reclassify_socket6(struct socket *sock)
2702 {
2703         struct sock *sk = sock->sk;
2704         BUG_ON(!sock_allow_reclassification(sk));
2705         sock_lock_init_class_and_name(sk, "slock-AF_INET6-CIFS",
2706                 &cifs_slock_key[1], "sk_lock-AF_INET6-CIFS", &cifs_key[1]);
2707 }
2708 #else
2709 static inline void
2710 cifs_reclassify_socket4(struct socket *sock)
2711 {
2712 }
2713
2714 static inline void
2715 cifs_reclassify_socket6(struct socket *sock)
2716 {
2717 }
2718 #endif
2719
2720 /* See RFC1001 section 14 on representation of Netbios names */
2721 static void rfc1002mangle(char *target, char *source, unsigned int length)
2722 {
2723         unsigned int i, j;
2724
2725         for (i = 0, j = 0; i < (length); i++) {
2726                 /* mask a nibble at a time and encode */
2727                 target[j] = 'A' + (0x0F & (source[i] >> 4));
2728                 target[j+1] = 'A' + (0x0F & source[i]);
2729                 j += 2;
2730         }
2731
2732 }
2733
2734 static int
2735 bind_socket(struct TCP_Server_Info *server)
2736 {
2737         int rc = 0;
2738         if (server->srcaddr.ss_family != AF_UNSPEC) {
2739                 /* Bind to the specified local IP address */
2740                 struct socket *socket = server->ssocket;
2741                 rc = socket->ops->bind(socket,
2742                                        (struct sockaddr *) &server->srcaddr,
2743                                        sizeof(server->srcaddr));
2744                 if (rc < 0) {
2745                         struct sockaddr_in *saddr4;
2746                         struct sockaddr_in6 *saddr6;
2747                         saddr4 = (struct sockaddr_in *)&server->srcaddr;
2748                         saddr6 = (struct sockaddr_in6 *)&server->srcaddr;
2749                         if (saddr6->sin6_family == AF_INET6)
2750                                 cifs_server_dbg(VFS, "Failed to bind to: %pI6c, error: %d\n",
2751                                          &saddr6->sin6_addr, rc);
2752                         else
2753                                 cifs_server_dbg(VFS, "Failed to bind to: %pI4, error: %d\n",
2754                                          &saddr4->sin_addr.s_addr, rc);
2755                 }
2756         }
2757         return rc;
2758 }
2759
2760 static int
2761 ip_rfc1001_connect(struct TCP_Server_Info *server)
2762 {
2763         int rc = 0;
2764         /*
2765          * some servers require RFC1001 sessinit before sending
2766          * negprot - BB check reconnection in case where second
2767          * sessinit is sent but no second negprot
2768          */
2769         struct rfc1002_session_packet *ses_init_buf;
2770         struct smb_hdr *smb_buf;
2771         ses_init_buf = kzalloc(sizeof(struct rfc1002_session_packet),
2772                                GFP_KERNEL);
2773         if (ses_init_buf) {
2774                 ses_init_buf->trailer.session_req.called_len = 32;
2775
2776                 if (server->server_RFC1001_name[0] != 0)
2777                         rfc1002mangle(ses_init_buf->trailer.
2778                                       session_req.called_name,
2779                                       server->server_RFC1001_name,
2780                                       RFC1001_NAME_LEN_WITH_NULL);
2781                 else
2782                         rfc1002mangle(ses_init_buf->trailer.
2783                                       session_req.called_name,
2784                                       DEFAULT_CIFS_CALLED_NAME,
2785                                       RFC1001_NAME_LEN_WITH_NULL);
2786
2787                 ses_init_buf->trailer.session_req.calling_len = 32;
2788
2789                 /*
2790                  * calling name ends in null (byte 16) from old smb
2791                  * convention.
2792                  */
2793                 if (server->workstation_RFC1001_name[0] != 0)
2794                         rfc1002mangle(ses_init_buf->trailer.
2795                                       session_req.calling_name,
2796                                       server->workstation_RFC1001_name,
2797                                       RFC1001_NAME_LEN_WITH_NULL);
2798                 else
2799                         rfc1002mangle(ses_init_buf->trailer.
2800                                       session_req.calling_name,
2801                                       "LINUX_CIFS_CLNT",
2802                                       RFC1001_NAME_LEN_WITH_NULL);
2803
2804                 ses_init_buf->trailer.session_req.scope1 = 0;
2805                 ses_init_buf->trailer.session_req.scope2 = 0;
2806                 smb_buf = (struct smb_hdr *)ses_init_buf;
2807
2808                 /* sizeof RFC1002_SESSION_REQUEST with no scope */
2809                 smb_buf->smb_buf_length = cpu_to_be32(0x81000044);
2810                 rc = smb_send(server, smb_buf, 0x44);
2811                 kfree(ses_init_buf);
2812                 /*
2813                  * RFC1001 layer in at least one server
2814                  * requires very short break before negprot
2815                  * presumably because not expecting negprot
2816                  * to follow so fast.  This is a simple
2817                  * solution that works without
2818                  * complicating the code and causes no
2819                  * significant slowing down on mount
2820                  * for everyone else
2821                  */
2822                 usleep_range(1000, 2000);
2823         }
2824         /*
2825          * else the negprot may still work without this
2826          * even though malloc failed
2827          */
2828
2829         return rc;
2830 }
2831
2832 static int
2833 generic_ip_connect(struct TCP_Server_Info *server)
2834 {
2835         int rc = 0;
2836         __be16 sport;
2837         int slen, sfamily;
2838         struct socket *socket = server->ssocket;
2839         struct sockaddr *saddr;
2840
2841         saddr = (struct sockaddr *) &server->dstaddr;
2842
2843         if (server->dstaddr.ss_family == AF_INET6) {
2844                 struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)&server->dstaddr;
2845
2846                 sport = ipv6->sin6_port;
2847                 slen = sizeof(struct sockaddr_in6);
2848                 sfamily = AF_INET6;
2849                 cifs_dbg(FYI, "%s: connecting to [%pI6]:%d\n", __func__, &ipv6->sin6_addr,
2850                                 ntohs(sport));
2851         } else {
2852                 struct sockaddr_in *ipv4 = (struct sockaddr_in *)&server->dstaddr;
2853
2854                 sport = ipv4->sin_port;
2855                 slen = sizeof(struct sockaddr_in);
2856                 sfamily = AF_INET;
2857                 cifs_dbg(FYI, "%s: connecting to %pI4:%d\n", __func__, &ipv4->sin_addr,
2858                                 ntohs(sport));
2859         }
2860
2861         if (socket == NULL) {
2862                 rc = __sock_create(cifs_net_ns(server), sfamily, SOCK_STREAM,
2863                                    IPPROTO_TCP, &socket, 1);
2864                 if (rc < 0) {
2865                         cifs_server_dbg(VFS, "Error %d creating socket\n", rc);
2866                         server->ssocket = NULL;
2867                         return rc;
2868                 }
2869
2870                 /* BB other socket options to set KEEPALIVE, NODELAY? */
2871                 cifs_dbg(FYI, "Socket created\n");
2872                 server->ssocket = socket;
2873                 socket->sk->sk_allocation = GFP_NOFS;
2874                 if (sfamily == AF_INET6)
2875                         cifs_reclassify_socket6(socket);
2876                 else
2877                         cifs_reclassify_socket4(socket);
2878         }
2879
2880         rc = bind_socket(server);
2881         if (rc < 0)
2882                 return rc;
2883
2884         /*
2885          * Eventually check for other socket options to change from
2886          * the default. sock_setsockopt not used because it expects
2887          * user space buffer
2888          */
2889         socket->sk->sk_rcvtimeo = 7 * HZ;
2890         socket->sk->sk_sndtimeo = 5 * HZ;
2891
2892         /* make the bufsizes depend on wsize/rsize and max requests */
2893         if (server->noautotune) {
2894                 if (socket->sk->sk_sndbuf < (200 * 1024))
2895                         socket->sk->sk_sndbuf = 200 * 1024;
2896                 if (socket->sk->sk_rcvbuf < (140 * 1024))
2897                         socket->sk->sk_rcvbuf = 140 * 1024;
2898         }
2899
2900         if (server->tcp_nodelay)
2901                 tcp_sock_set_nodelay(socket->sk);
2902
2903         cifs_dbg(FYI, "sndbuf %d rcvbuf %d rcvtimeo 0x%lx\n",
2904                  socket->sk->sk_sndbuf,
2905                  socket->sk->sk_rcvbuf, socket->sk->sk_rcvtimeo);
2906
2907         rc = socket->ops->connect(socket, saddr, slen,
2908                                   server->noblockcnt ? O_NONBLOCK : 0);
2909         /*
2910          * When mounting SMB root file systems, we do not want to block in
2911          * connect. Otherwise bail out and then let cifs_reconnect() perform
2912          * reconnect failover - if possible.
2913          */
2914         if (server->noblockcnt && rc == -EINPROGRESS)
2915                 rc = 0;
2916         if (rc < 0) {
2917                 cifs_dbg(FYI, "Error %d connecting to server\n", rc);
2918                 trace_smb3_connect_err(server->hostname, server->conn_id, &server->dstaddr, rc);
2919                 sock_release(socket);
2920                 server->ssocket = NULL;
2921                 return rc;
2922         }
2923         trace_smb3_connect_done(server->hostname, server->conn_id, &server->dstaddr);
2924         if (sport == htons(RFC1001_PORT))
2925                 rc = ip_rfc1001_connect(server);
2926
2927         return rc;
2928 }
2929
2930 static int
2931 ip_connect(struct TCP_Server_Info *server)
2932 {
2933         __be16 *sport;
2934         struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
2935         struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
2936
2937         if (server->dstaddr.ss_family == AF_INET6)
2938                 sport = &addr6->sin6_port;
2939         else
2940                 sport = &addr->sin_port;
2941
2942         if (*sport == 0) {
2943                 int rc;
2944
2945                 /* try with 445 port at first */
2946                 *sport = htons(CIFS_PORT);
2947
2948                 rc = generic_ip_connect(server);
2949                 if (rc >= 0)
2950                         return rc;
2951
2952                 /* if it failed, try with 139 port */
2953                 *sport = htons(RFC1001_PORT);
2954         }
2955
2956         return generic_ip_connect(server);
2957 }
2958
2959 void reset_cifs_unix_caps(unsigned int xid, struct cifs_tcon *tcon,
2960                           struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
2961 {
2962         /*
2963          * If we are reconnecting then should we check to see if
2964          * any requested capabilities changed locally e.g. via
2965          * remount but we can not do much about it here
2966          * if they have (even if we could detect it by the following)
2967          * Perhaps we could add a backpointer to array of sb from tcon
2968          * or if we change to make all sb to same share the same
2969          * sb as NFS - then we only have one backpointer to sb.
2970          * What if we wanted to mount the server share twice once with
2971          * and once without posixacls or posix paths?
2972          */
2973         __u64 saved_cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
2974
2975         if (ctx && ctx->no_linux_ext) {
2976                 tcon->fsUnixInfo.Capability = 0;
2977                 tcon->unix_ext = 0; /* Unix Extensions disabled */
2978                 cifs_dbg(FYI, "Linux protocol extensions disabled\n");
2979                 return;
2980         } else if (ctx)
2981                 tcon->unix_ext = 1; /* Unix Extensions supported */
2982
2983         if (!tcon->unix_ext) {
2984                 cifs_dbg(FYI, "Unix extensions disabled so not set on reconnect\n");
2985                 return;
2986         }
2987
2988         if (!CIFSSMBQFSUnixInfo(xid, tcon)) {
2989                 __u64 cap = le64_to_cpu(tcon->fsUnixInfo.Capability);
2990                 cifs_dbg(FYI, "unix caps which server supports %lld\n", cap);
2991                 /*
2992                  * check for reconnect case in which we do not
2993                  * want to change the mount behavior if we can avoid it
2994                  */
2995                 if (ctx == NULL) {
2996                         /*
2997                          * turn off POSIX ACL and PATHNAMES if not set
2998                          * originally at mount time
2999                          */
3000                         if ((saved_cap & CIFS_UNIX_POSIX_ACL_CAP) == 0)
3001                                 cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
3002                         if ((saved_cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
3003                                 if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
3004                                         cifs_dbg(VFS, "POSIXPATH support change\n");
3005                                 cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
3006                         } else if ((cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) == 0) {
3007                                 cifs_dbg(VFS, "possible reconnect error\n");
3008                                 cifs_dbg(VFS, "server disabled POSIX path support\n");
3009                         }
3010                 }
3011
3012                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
3013                         cifs_dbg(VFS, "per-share encryption not supported yet\n");
3014
3015                 cap &= CIFS_UNIX_CAP_MASK;
3016                 if (ctx && ctx->no_psx_acl)
3017                         cap &= ~CIFS_UNIX_POSIX_ACL_CAP;
3018                 else if (CIFS_UNIX_POSIX_ACL_CAP & cap) {
3019                         cifs_dbg(FYI, "negotiated posix acl support\n");
3020                         if (cifs_sb)
3021                                 cifs_sb->mnt_cifs_flags |=
3022                                         CIFS_MOUNT_POSIXACL;
3023                 }
3024
3025                 if (ctx && ctx->posix_paths == 0)
3026                         cap &= ~CIFS_UNIX_POSIX_PATHNAMES_CAP;
3027                 else if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP) {
3028                         cifs_dbg(FYI, "negotiate posix pathnames\n");
3029                         if (cifs_sb)
3030                                 cifs_sb->mnt_cifs_flags |=
3031                                         CIFS_MOUNT_POSIX_PATHS;
3032                 }
3033
3034                 cifs_dbg(FYI, "Negotiate caps 0x%x\n", (int)cap);
3035 #ifdef CONFIG_CIFS_DEBUG2
3036                 if (cap & CIFS_UNIX_FCNTL_CAP)
3037                         cifs_dbg(FYI, "FCNTL cap\n");
3038                 if (cap & CIFS_UNIX_EXTATTR_CAP)
3039                         cifs_dbg(FYI, "EXTATTR cap\n");
3040                 if (cap & CIFS_UNIX_POSIX_PATHNAMES_CAP)
3041                         cifs_dbg(FYI, "POSIX path cap\n");
3042                 if (cap & CIFS_UNIX_XATTR_CAP)
3043                         cifs_dbg(FYI, "XATTR cap\n");
3044                 if (cap & CIFS_UNIX_POSIX_ACL_CAP)
3045                         cifs_dbg(FYI, "POSIX ACL cap\n");
3046                 if (cap & CIFS_UNIX_LARGE_READ_CAP)
3047                         cifs_dbg(FYI, "very large read cap\n");
3048                 if (cap & CIFS_UNIX_LARGE_WRITE_CAP)
3049                         cifs_dbg(FYI, "very large write cap\n");
3050                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_CAP)
3051                         cifs_dbg(FYI, "transport encryption cap\n");
3052                 if (cap & CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)
3053                         cifs_dbg(FYI, "mandatory transport encryption cap\n");
3054 #endif /* CIFS_DEBUG2 */
3055                 if (CIFSSMBSetFSUnixInfo(xid, tcon, cap)) {
3056                         if (ctx == NULL)
3057                                 cifs_dbg(FYI, "resetting capabilities failed\n");
3058                         else
3059                                 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");
3060
3061                 }
3062         }
3063 }
3064
3065 int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb)
3066 {
3067         struct smb3_fs_context *ctx = cifs_sb->ctx;
3068
3069         INIT_DELAYED_WORK(&cifs_sb->prune_tlinks, cifs_prune_tlinks);
3070
3071         spin_lock_init(&cifs_sb->tlink_tree_lock);
3072         cifs_sb->tlink_tree = RB_ROOT;
3073
3074         cifs_dbg(FYI, "file mode: %04ho  dir mode: %04ho\n",
3075                  ctx->file_mode, ctx->dir_mode);
3076
3077         /* this is needed for ASCII cp to Unicode converts */
3078         if (ctx->iocharset == NULL) {
3079                 /* load_nls_default cannot return null */
3080                 cifs_sb->local_nls = load_nls_default();
3081         } else {
3082                 cifs_sb->local_nls = load_nls(ctx->iocharset);
3083                 if (cifs_sb->local_nls == NULL) {
3084                         cifs_dbg(VFS, "CIFS mount error: iocharset %s not found\n",
3085                                  ctx->iocharset);
3086                         return -ELIBACC;
3087                 }
3088         }
3089         ctx->local_nls = cifs_sb->local_nls;
3090
3091         smb3_update_mnt_flags(cifs_sb);
3092
3093         if (ctx->direct_io)
3094                 cifs_dbg(FYI, "mounting share using direct i/o\n");
3095         if (ctx->cache_ro) {
3096                 cifs_dbg(VFS, "mounting share with read only caching. Ensure that the share will not be modified while in use.\n");
3097                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RO_CACHE;
3098         } else if (ctx->cache_rw) {
3099                 cifs_dbg(VFS, "mounting share in single client RW caching mode. Ensure that no other systems will be accessing the share.\n");
3100                 cifs_sb->mnt_cifs_flags |= (CIFS_MOUNT_RO_CACHE |
3101                                             CIFS_MOUNT_RW_CACHE);
3102         }
3103
3104         if ((ctx->cifs_acl) && (ctx->dynperm))
3105                 cifs_dbg(VFS, "mount option dynperm ignored if cifsacl mount option supported\n");
3106
3107         if (ctx->prepath) {
3108                 cifs_sb->prepath = kstrdup(ctx->prepath, GFP_KERNEL);
3109                 if (cifs_sb->prepath == NULL)
3110                         return -ENOMEM;
3111                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3112         }
3113
3114         return 0;
3115 }
3116
3117 /* Release all succeed connections */
3118 static inline void mount_put_conns(struct mount_ctx *mnt_ctx)
3119 {
3120         int rc = 0;
3121
3122         if (mnt_ctx->tcon)
3123                 cifs_put_tcon(mnt_ctx->tcon);
3124         else if (mnt_ctx->ses)
3125                 cifs_put_smb_ses(mnt_ctx->ses);
3126         else if (mnt_ctx->server)
3127                 cifs_put_tcp_session(mnt_ctx->server, 0);
3128         mnt_ctx->cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_POSIX_PATHS;
3129         free_xid(mnt_ctx->xid);
3130 }
3131
3132 /* Get connections for tcp, ses and tcon */
3133 static int mount_get_conns(struct mount_ctx *mnt_ctx)
3134 {
3135         int rc = 0;
3136         struct TCP_Server_Info *server = NULL;
3137         struct cifs_ses *ses = NULL;
3138         struct cifs_tcon *tcon = NULL;
3139         struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3140         struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3141         unsigned int xid;
3142
3143         xid = get_xid();
3144
3145         /* get a reference to a tcp session */
3146         server = cifs_get_tcp_session(ctx, NULL);
3147         if (IS_ERR(server)) {
3148                 rc = PTR_ERR(server);
3149                 server = NULL;
3150                 goto out;
3151         }
3152
3153         /* get a reference to a SMB session */
3154         ses = cifs_get_smb_ses(server, ctx);
3155         if (IS_ERR(ses)) {
3156                 rc = PTR_ERR(ses);
3157                 ses = NULL;
3158                 goto out;
3159         }
3160
3161         if ((ctx->persistent == true) && (!(ses->server->capabilities &
3162                                             SMB2_GLOBAL_CAP_PERSISTENT_HANDLES))) {
3163                 cifs_server_dbg(VFS, "persistent handles not supported by server\n");
3164                 rc = -EOPNOTSUPP;
3165                 goto out;
3166         }
3167
3168         /* search for existing tcon to this server share */
3169         tcon = cifs_get_tcon(ses, ctx);
3170         if (IS_ERR(tcon)) {
3171                 rc = PTR_ERR(tcon);
3172                 tcon = NULL;
3173                 goto out;
3174         }
3175
3176         /* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
3177         if (tcon->posix_extensions)
3178                 cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_POSIX_PATHS;
3179
3180         /* tell server which Unix caps we support */
3181         if (cap_unix(tcon->ses)) {
3182                 /*
3183                  * reset of caps checks mount to see if unix extensions disabled
3184                  * for just this mount.
3185                  */
3186                 reset_cifs_unix_caps(xid, tcon, cifs_sb, ctx);
3187                 spin_lock(&cifs_tcp_ses_lock);
3188                 if ((tcon->ses->server->tcpStatus == CifsNeedReconnect) &&
3189                     (le64_to_cpu(tcon->fsUnixInfo.Capability) &
3190                      CIFS_UNIX_TRANSPORT_ENCRYPTION_MANDATORY_CAP)) {
3191                         spin_unlock(&cifs_tcp_ses_lock);
3192                         rc = -EACCES;
3193                         goto out;
3194                 }
3195                 spin_unlock(&cifs_tcp_ses_lock);
3196         } else
3197                 tcon->unix_ext = 0; /* server does not support them */
3198
3199         /* do not care if a following call succeed - informational */
3200         if (!tcon->pipe && server->ops->qfs_tcon) {
3201                 server->ops->qfs_tcon(xid, tcon, cifs_sb);
3202                 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RO_CACHE) {
3203                         if (tcon->fsDevInfo.DeviceCharacteristics &
3204                             cpu_to_le32(FILE_READ_ONLY_DEVICE))
3205                                 cifs_dbg(VFS, "mounted to read only share\n");
3206                         else if ((cifs_sb->mnt_cifs_flags &
3207                                   CIFS_MOUNT_RW_CACHE) == 0)
3208                                 cifs_dbg(VFS, "read only mount of RW share\n");
3209                         /* no need to log a RW mount of a typical RW share */
3210                 }
3211         }
3212
3213         /*
3214          * Clamp the rsize/wsize mount arguments if they are too big for the server
3215          * and set the rsize/wsize to the negotiated values if not passed in by
3216          * the user on mount
3217          */
3218         if ((cifs_sb->ctx->wsize == 0) ||
3219             (cifs_sb->ctx->wsize > server->ops->negotiate_wsize(tcon, ctx)))
3220                 cifs_sb->ctx->wsize = server->ops->negotiate_wsize(tcon, ctx);
3221         if ((cifs_sb->ctx->rsize == 0) ||
3222             (cifs_sb->ctx->rsize > server->ops->negotiate_rsize(tcon, ctx)))
3223                 cifs_sb->ctx->rsize = server->ops->negotiate_rsize(tcon, ctx);
3224
3225         /*
3226          * The cookie is initialized from volume info returned above.
3227          * Inside cifs_fscache_get_super_cookie it checks
3228          * that we do not get super cookie twice.
3229          */
3230         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_FSCACHE)
3231                 cifs_fscache_get_super_cookie(tcon);
3232
3233 out:
3234         mnt_ctx->server = server;
3235         mnt_ctx->ses = ses;
3236         mnt_ctx->tcon = tcon;
3237         mnt_ctx->xid = xid;
3238
3239         return rc;
3240 }
3241
3242 static int mount_setup_tlink(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
3243                              struct cifs_tcon *tcon)
3244 {
3245         struct tcon_link *tlink;
3246
3247         /* hang the tcon off of the superblock */
3248         tlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
3249         if (tlink == NULL)
3250                 return -ENOMEM;
3251
3252         tlink->tl_uid = ses->linux_uid;
3253         tlink->tl_tcon = tcon;
3254         tlink->tl_time = jiffies;
3255         set_bit(TCON_LINK_MASTER, &tlink->tl_flags);
3256         set_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3257
3258         cifs_sb->master_tlink = tlink;
3259         spin_lock(&cifs_sb->tlink_tree_lock);
3260         tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
3261         spin_unlock(&cifs_sb->tlink_tree_lock);
3262
3263         queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
3264                                 TLINK_IDLE_EXPIRE);
3265         return 0;
3266 }
3267
3268 #ifdef CONFIG_CIFS_DFS_UPCALL
3269 /* Get unique dfs connections */
3270 static int mount_get_dfs_conns(struct mount_ctx *mnt_ctx)
3271 {
3272         int rc;
3273
3274         mnt_ctx->fs_ctx->nosharesock = true;
3275         rc = mount_get_conns(mnt_ctx);
3276         if (mnt_ctx->server) {
3277                 cifs_dbg(FYI, "%s: marking tcp session as a dfs connection\n", __func__);
3278                 spin_lock(&cifs_tcp_ses_lock);
3279                 mnt_ctx->server->is_dfs_conn = true;
3280                 spin_unlock(&cifs_tcp_ses_lock);
3281         }
3282         return rc;
3283 }
3284
3285 /*
3286  * cifs_build_path_to_root returns full path to root when we do not have an
3287  * existing connection (tcon)
3288  */
3289 static char *
3290 build_unc_path_to_root(const struct smb3_fs_context *ctx,
3291                        const struct cifs_sb_info *cifs_sb, bool useppath)
3292 {
3293         char *full_path, *pos;
3294         unsigned int pplen = useppath && ctx->prepath ?
3295                 strlen(ctx->prepath) + 1 : 0;
3296         unsigned int unc_len = strnlen(ctx->UNC, MAX_TREE_SIZE + 1);
3297
3298         if (unc_len > MAX_TREE_SIZE)
3299                 return ERR_PTR(-EINVAL);
3300
3301         full_path = kmalloc(unc_len + pplen + 1, GFP_KERNEL);
3302         if (full_path == NULL)
3303                 return ERR_PTR(-ENOMEM);
3304
3305         memcpy(full_path, ctx->UNC, unc_len);
3306         pos = full_path + unc_len;
3307
3308         if (pplen) {
3309                 *pos = CIFS_DIR_SEP(cifs_sb);
3310                 memcpy(pos + 1, ctx->prepath, pplen);
3311                 pos += pplen;
3312         }
3313
3314         *pos = '\0'; /* add trailing null */
3315         convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb));
3316         cifs_dbg(FYI, "%s: full_path=%s\n", __func__, full_path);
3317         return full_path;
3318 }
3319
3320 /*
3321  * expand_dfs_referral - Update cifs_sb from dfs referral path
3322  *
3323  * cifs_sb->ctx->mount_options will be (re-)allocated to a string containing updated options for the
3324  * submount.  Otherwise it will be left untouched.
3325  */
3326 static int expand_dfs_referral(struct mount_ctx *mnt_ctx, const char *full_path,
3327                                struct dfs_info3_param *referral)
3328 {
3329         int rc;
3330         struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3331         struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3332         char *fake_devname = NULL, *mdata = NULL;
3333
3334         mdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options, full_path + 1, referral,
3335                                            &fake_devname);
3336         if (IS_ERR(mdata)) {
3337                 rc = PTR_ERR(mdata);
3338                 mdata = NULL;
3339         } else {
3340                 /*
3341                  * We can not clear out the whole structure since we no longer have an explicit
3342                  * function to parse a mount-string. Instead we need to clear out the individual
3343                  * fields that are no longer valid.
3344                  */
3345                 kfree(ctx->prepath);
3346                 ctx->prepath = NULL;
3347                 rc = cifs_setup_volume_info(ctx, mdata, fake_devname);
3348         }
3349         kfree(fake_devname);
3350         kfree(cifs_sb->ctx->mount_options);
3351         cifs_sb->ctx->mount_options = mdata;
3352
3353         return rc;
3354 }
3355 #endif
3356
3357 /* TODO: all callers to this are broken. We are not parsing mount_options here
3358  * we should pass a clone of the original context?
3359  */
3360 int
3361 cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname)
3362 {
3363         int rc;
3364
3365         if (devname) {
3366                 cifs_dbg(FYI, "%s: devname=%s\n", __func__, devname);
3367                 rc = smb3_parse_devname(devname, ctx);
3368                 if (rc) {
3369                         cifs_dbg(VFS, "%s: failed to parse %s: %d\n", __func__, devname, rc);
3370                         return rc;
3371                 }
3372         }
3373
3374         if (mntopts) {
3375                 char *ip;
3376
3377                 rc = smb3_parse_opt(mntopts, "ip", &ip);
3378                 if (rc) {
3379                         cifs_dbg(VFS, "%s: failed to parse ip options: %d\n", __func__, rc);
3380                         return rc;
3381                 }
3382
3383                 rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip));
3384                 kfree(ip);
3385                 if (!rc) {
3386                         cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);
3387                         return -EINVAL;
3388                 }
3389         }
3390
3391         if (ctx->nullauth) {
3392                 cifs_dbg(FYI, "Anonymous login\n");
3393                 kfree(ctx->username);
3394                 ctx->username = NULL;
3395         } else if (ctx->username) {
3396                 /* BB fixme parse for domain name here */
3397                 cifs_dbg(FYI, "Username: %s\n", ctx->username);
3398         } else {
3399                 cifs_dbg(VFS, "No username specified\n");
3400         /* In userspace mount helper we can get user name from alternate
3401            locations such as env variables and files on disk */
3402                 return -EINVAL;
3403         }
3404
3405         return 0;
3406 }
3407
3408 static int
3409 cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
3410                                         unsigned int xid,
3411                                         struct cifs_tcon *tcon,
3412                                         struct cifs_sb_info *cifs_sb,
3413                                         char *full_path,
3414                                         int added_treename)
3415 {
3416         int rc;
3417         char *s;
3418         char sep, tmp;
3419         int skip = added_treename ? 1 : 0;
3420
3421         sep = CIFS_DIR_SEP(cifs_sb);
3422         s = full_path;
3423
3424         rc = server->ops->is_path_accessible(xid, tcon, cifs_sb, "");
3425         while (rc == 0) {
3426                 /* skip separators */
3427                 while (*s == sep)
3428                         s++;
3429                 if (!*s)
3430                         break;
3431                 /* next separator */
3432                 while (*s && *s != sep)
3433                         s++;
3434                 /*
3435                  * if the treename is added, we then have to skip the first
3436                  * part within the separators
3437                  */
3438                 if (skip) {
3439                         skip = 0;
3440                         continue;
3441                 }
3442                 /*
3443                  * temporarily null-terminate the path at the end of
3444                  * the current component
3445                  */
3446                 tmp = *s;
3447                 *s = 0;
3448                 rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3449                                                      full_path);
3450                 *s = tmp;
3451         }
3452         return rc;
3453 }
3454
3455 /*
3456  * Check if path is remote (i.e. a DFS share).
3457  *
3458  * Return -EREMOTE if it is, otherwise 0 or -errno.
3459  */
3460 static int is_path_remote(struct mount_ctx *mnt_ctx)
3461 {
3462         int rc;
3463         struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3464         struct TCP_Server_Info *server = mnt_ctx->server;
3465         unsigned int xid = mnt_ctx->xid;
3466         struct cifs_tcon *tcon = mnt_ctx->tcon;
3467         struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3468         char *full_path;
3469 #ifdef CONFIG_CIFS_DFS_UPCALL
3470         bool nodfs = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS;
3471 #endif
3472
3473         if (!server->ops->is_path_accessible)
3474                 return -EOPNOTSUPP;
3475
3476         /*
3477          * cifs_build_path_to_root works only when we have a valid tcon
3478          */
3479         full_path = cifs_build_path_to_root(ctx, cifs_sb, tcon,
3480                                             tcon->Flags & SMB_SHARE_IS_IN_DFS);
3481         if (full_path == NULL)
3482                 return -ENOMEM;
3483
3484         cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
3485
3486         rc = server->ops->is_path_accessible(xid, tcon, cifs_sb,
3487                                              full_path);
3488 #ifdef CONFIG_CIFS_DFS_UPCALL
3489         if (nodfs) {
3490                 if (rc == -EREMOTE)
3491                         rc = -EOPNOTSUPP;
3492                 goto out;
3493         }
3494
3495         /* path *might* exist with non-ASCII characters in DFS root
3496          * try again with full path (only if nodfs is not set) */
3497         if (rc == -ENOENT && is_tcon_dfs(tcon))
3498                 rc = cifs_dfs_query_info_nonascii_quirk(xid, tcon, cifs_sb,
3499                                                         full_path);
3500 #endif
3501         if (rc != 0 && rc != -EREMOTE)
3502                 goto out;
3503
3504         if (rc != -EREMOTE) {
3505                 rc = cifs_are_all_path_components_accessible(server, xid, tcon,
3506                         cifs_sb, full_path, tcon->Flags & SMB_SHARE_IS_IN_DFS);
3507                 if (rc != 0) {
3508                         cifs_server_dbg(VFS, "cannot query dirs between root and final path, enabling CIFS_MOUNT_USE_PREFIX_PATH\n");
3509                         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3510                         rc = 0;
3511                 }
3512         }
3513
3514 out:
3515         kfree(full_path);
3516         return rc;
3517 }
3518
3519 #ifdef CONFIG_CIFS_DFS_UPCALL
3520 static void set_root_ses(struct mount_ctx *mnt_ctx)
3521 {
3522         if (mnt_ctx->ses) {
3523                 spin_lock(&cifs_tcp_ses_lock);
3524                 mnt_ctx->ses->ses_count++;
3525                 spin_unlock(&cifs_tcp_ses_lock);
3526                 dfs_cache_add_refsrv_session(&mnt_ctx->mount_id, mnt_ctx->ses);
3527         }
3528         mnt_ctx->root_ses = mnt_ctx->ses;
3529 }
3530
3531 static int is_dfs_mount(struct mount_ctx *mnt_ctx, bool *isdfs, struct dfs_cache_tgt_list *root_tl)
3532 {
3533         int rc;
3534         struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3535         struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3536
3537         *isdfs = true;
3538
3539         rc = mount_get_conns(mnt_ctx);
3540         /*
3541          * If called with 'nodfs' mount option, then skip DFS resolving.  Otherwise unconditionally
3542          * try to get an DFS referral (even cached) to determine whether it is an DFS mount.
3543          *
3544          * Skip prefix path to provide support for DFS referrals from w2k8 servers which don't seem
3545          * to respond with PATH_NOT_COVERED to requests that include the prefix.
3546          */
3547         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
3548             dfs_cache_find(mnt_ctx->xid, mnt_ctx->ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
3549                            ctx->UNC + 1, NULL, root_tl)) {
3550                 if (rc)
3551                         return rc;
3552                 /* Check if it is fully accessible and then mount it */
3553                 rc = is_path_remote(mnt_ctx);
3554                 if (!rc)
3555                         *isdfs = false;
3556                 else if (rc != -EREMOTE)
3557                         return rc;
3558         }
3559         return 0;
3560 }
3561
3562 static int connect_dfs_target(struct mount_ctx *mnt_ctx, const char *full_path,
3563                               const char *ref_path, struct dfs_cache_tgt_iterator *tit)
3564 {
3565         int rc;
3566         struct dfs_info3_param ref = {};
3567         struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3568         char *oldmnt = cifs_sb->ctx->mount_options;
3569
3570         cifs_dbg(FYI, "%s: full_path=%s ref_path=%s target=%s\n", __func__, full_path, ref_path,
3571                  dfs_cache_get_tgt_name(tit));
3572
3573         rc = dfs_cache_get_tgt_referral(ref_path, tit, &ref);
3574         if (rc)
3575                 goto out;
3576
3577         rc = expand_dfs_referral(mnt_ctx, full_path, &ref);
3578         if (rc)
3579                 goto out;
3580
3581         /* Connect to new target only if we were redirected (e.g. mount options changed) */
3582         if (oldmnt != cifs_sb->ctx->mount_options) {
3583                 mount_put_conns(mnt_ctx);
3584                 rc = mount_get_dfs_conns(mnt_ctx);
3585         }
3586         if (!rc) {
3587                 if (cifs_is_referral_server(mnt_ctx->tcon, &ref))
3588                         set_root_ses(mnt_ctx);
3589                 rc = dfs_cache_update_tgthint(mnt_ctx->xid, mnt_ctx->root_ses, cifs_sb->local_nls,
3590                                               cifs_remap(cifs_sb), ref_path, tit);
3591         }
3592
3593 out:
3594         free_dfs_info_param(&ref);
3595         return rc;
3596 }
3597
3598 static int connect_dfs_root(struct mount_ctx *mnt_ctx, struct dfs_cache_tgt_list *root_tl)
3599 {
3600         int rc;
3601         char *full_path;
3602         struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3603         struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3604         struct dfs_cache_tgt_iterator *tit;
3605
3606         /* Put initial connections as they might be shared with other mounts.  We need unique dfs
3607          * connections per mount to properly failover, so mount_get_dfs_conns() must be used from
3608          * now on.
3609          */
3610         mount_put_conns(mnt_ctx);
3611         mount_get_dfs_conns(mnt_ctx);
3612         set_root_ses(mnt_ctx);
3613
3614         full_path = build_unc_path_to_root(ctx, cifs_sb, true);
3615         if (IS_ERR(full_path))
3616                 return PTR_ERR(full_path);
3617
3618         mnt_ctx->origin_fullpath = dfs_cache_canonical_path(ctx->UNC, cifs_sb->local_nls,
3619                                                             cifs_remap(cifs_sb));
3620         if (IS_ERR(mnt_ctx->origin_fullpath)) {
3621                 rc = PTR_ERR(mnt_ctx->origin_fullpath);
3622                 mnt_ctx->origin_fullpath = NULL;
3623                 goto out;
3624         }
3625
3626         /* Try all dfs root targets */
3627         for (rc = -ENOENT, tit = dfs_cache_get_tgt_iterator(root_tl);
3628              tit; tit = dfs_cache_get_next_tgt(root_tl, tit)) {
3629                 rc = connect_dfs_target(mnt_ctx, full_path, mnt_ctx->origin_fullpath + 1, tit);
3630                 if (!rc) {
3631                         mnt_ctx->leaf_fullpath = kstrdup(mnt_ctx->origin_fullpath, GFP_KERNEL);
3632                         if (!mnt_ctx->leaf_fullpath)
3633                                 rc = -ENOMEM;
3634                         break;
3635                 }
3636         }
3637
3638 out:
3639         kfree(full_path);
3640         return rc;
3641 }
3642
3643 static int __follow_dfs_link(struct mount_ctx *mnt_ctx)
3644 {
3645         int rc;
3646         struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3647         struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3648         char *full_path;
3649         struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
3650         struct dfs_cache_tgt_iterator *tit;
3651
3652         full_path = build_unc_path_to_root(ctx, cifs_sb, true);
3653         if (IS_ERR(full_path))
3654                 return PTR_ERR(full_path);
3655
3656         kfree(mnt_ctx->leaf_fullpath);
3657         mnt_ctx->leaf_fullpath = dfs_cache_canonical_path(full_path, cifs_sb->local_nls,
3658                                                           cifs_remap(cifs_sb));
3659         if (IS_ERR(mnt_ctx->leaf_fullpath)) {
3660                 rc = PTR_ERR(mnt_ctx->leaf_fullpath);
3661                 mnt_ctx->leaf_fullpath = NULL;
3662                 goto out;
3663         }
3664
3665         /* Get referral from dfs link */
3666         rc = dfs_cache_find(mnt_ctx->xid, mnt_ctx->root_ses, cifs_sb->local_nls,
3667                             cifs_remap(cifs_sb), mnt_ctx->leaf_fullpath + 1, NULL, &tl);
3668         if (rc)
3669                 goto out;
3670
3671         /* Try all dfs link targets.  If an I/O fails from currently connected DFS target with an
3672          * error other than STATUS_PATH_NOT_COVERED (-EREMOTE), then retry it from other targets as
3673          * specified in MS-DFSC "3.1.5.2 I/O Operation to Target Fails with an Error Other Than
3674          * STATUS_PATH_NOT_COVERED."
3675          */
3676         for (rc = -ENOENT, tit = dfs_cache_get_tgt_iterator(&tl);
3677              tit; tit = dfs_cache_get_next_tgt(&tl, tit)) {
3678                 rc = connect_dfs_target(mnt_ctx, full_path, mnt_ctx->leaf_fullpath + 1, tit);
3679                 if (!rc) {
3680                         rc = is_path_remote(mnt_ctx);
3681                         if (!rc || rc == -EREMOTE)
3682                                 break;
3683                 }
3684         }
3685
3686 out:
3687         kfree(full_path);
3688         dfs_cache_free_tgts(&tl);
3689         return rc;
3690 }
3691
3692 static int follow_dfs_link(struct mount_ctx *mnt_ctx)
3693 {
3694         int rc;
3695         struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
3696         struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
3697         char *full_path;
3698         int num_links = 0;
3699
3700         full_path = build_unc_path_to_root(ctx, cifs_sb, true);
3701         if (IS_ERR(full_path))
3702                 return PTR_ERR(full_path);
3703
3704         kfree(mnt_ctx->origin_fullpath);
3705         mnt_ctx->origin_fullpath = dfs_cache_canonical_path(full_path, cifs_sb->local_nls,
3706                                                             cifs_remap(cifs_sb));
3707         kfree(full_path);
3708
3709         if (IS_ERR(mnt_ctx->origin_fullpath)) {
3710                 rc = PTR_ERR(mnt_ctx->origin_fullpath);
3711                 mnt_ctx->origin_fullpath = NULL;
3712                 return rc;
3713         }
3714
3715         do {
3716                 rc = __follow_dfs_link(mnt_ctx);
3717                 if (!rc || rc != -EREMOTE)
3718                         break;
3719         } while (rc = -ELOOP, ++num_links < MAX_NESTED_LINKS);
3720
3721         return rc;
3722 }
3723
3724 /* Set up DFS referral paths for failover */
3725 static void setup_server_referral_paths(struct mount_ctx *mnt_ctx)
3726 {
3727         struct TCP_Server_Info *server = mnt_ctx->server;
3728
3729         mutex_lock(&server->refpath_lock);
3730         server->origin_fullpath = mnt_ctx->origin_fullpath;
3731         server->leaf_fullpath = mnt_ctx->leaf_fullpath;
3732         server->current_fullpath = mnt_ctx->leaf_fullpath;
3733         mutex_unlock(&server->refpath_lock);
3734         mnt_ctx->origin_fullpath = mnt_ctx->leaf_fullpath = NULL;
3735 }
3736
3737 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3738 {
3739         int rc;
3740         struct mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
3741         struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
3742         bool isdfs;
3743
3744         rc = is_dfs_mount(&mnt_ctx, &isdfs, &tl);
3745         if (rc)
3746                 goto error;
3747         if (!isdfs)
3748                 goto out;
3749
3750         /* proceed as DFS mount */
3751         uuid_gen(&mnt_ctx.mount_id);
3752         rc = connect_dfs_root(&mnt_ctx, &tl);
3753         dfs_cache_free_tgts(&tl);
3754
3755         if (rc)
3756                 goto error;
3757
3758         rc = is_path_remote(&mnt_ctx);
3759         if (rc)
3760                 rc = follow_dfs_link(&mnt_ctx);
3761         if (rc)
3762                 goto error;
3763
3764         setup_server_referral_paths(&mnt_ctx);
3765         /*
3766          * After reconnecting to a different server, unique ids won't match anymore, so we disable
3767          * serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE).
3768          */
3769         cifs_autodisable_serverino(cifs_sb);
3770         /*
3771          * Force the use of prefix path to support failover on DFS paths that resolve to targets
3772          * that have different prefix paths.
3773          */
3774         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
3775         kfree(cifs_sb->prepath);
3776         cifs_sb->prepath = ctx->prepath;
3777         ctx->prepath = NULL;
3778         uuid_copy(&cifs_sb->dfs_mount_id, &mnt_ctx.mount_id);
3779
3780 out:
3781         free_xid(mnt_ctx.xid);
3782         cifs_try_adding_channels(cifs_sb, mnt_ctx.ses);
3783         return mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
3784
3785 error:
3786         dfs_cache_put_refsrv_sessions(&mnt_ctx.mount_id);
3787         kfree(mnt_ctx.origin_fullpath);
3788         kfree(mnt_ctx.leaf_fullpath);
3789         mount_put_conns(&mnt_ctx);
3790         return rc;
3791 }
3792 #else
3793 int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
3794 {
3795         int rc = 0;
3796         struct mount_ctx mnt_ctx = { .cifs_sb = cifs_sb, .fs_ctx = ctx, };
3797
3798         rc = mount_get_conns(&mnt_ctx);
3799         if (rc)
3800                 goto error;
3801
3802         if (mnt_ctx.tcon) {
3803                 rc = is_path_remote(&mnt_ctx);
3804                 if (rc == -EREMOTE)
3805                         rc = -EOPNOTSUPP;
3806                 if (rc)
3807                         goto error;
3808         }
3809
3810         free_xid(mnt_ctx.xid);
3811         return mount_setup_tlink(cifs_sb, mnt_ctx.ses, mnt_ctx.tcon);
3812
3813 error:
3814         mount_put_conns(&mnt_ctx);
3815         return rc;
3816 }
3817 #endif
3818
3819 /*
3820  * Issue a TREE_CONNECT request.
3821  */
3822 int
3823 CIFSTCon(const unsigned int xid, struct cifs_ses *ses,
3824          const char *tree, struct cifs_tcon *tcon,
3825          const struct nls_table *nls_codepage)
3826 {
3827         struct smb_hdr *smb_buffer;
3828         struct smb_hdr *smb_buffer_response;
3829         TCONX_REQ *pSMB;
3830         TCONX_RSP *pSMBr;
3831         unsigned char *bcc_ptr;
3832         int rc = 0;
3833         int length;
3834         __u16 bytes_left, count;
3835
3836         if (ses == NULL)
3837                 return -EIO;
3838
3839         smb_buffer = cifs_buf_get();
3840         if (smb_buffer == NULL)
3841                 return -ENOMEM;
3842
3843         smb_buffer_response = smb_buffer;
3844
3845         header_assemble(smb_buffer, SMB_COM_TREE_CONNECT_ANDX,
3846                         NULL /*no tid */ , 4 /*wct */ );
3847
3848         smb_buffer->Mid = get_next_mid(ses->server);
3849         smb_buffer->Uid = ses->Suid;
3850         pSMB = (TCONX_REQ *) smb_buffer;
3851         pSMBr = (TCONX_RSP *) smb_buffer_response;
3852
3853         pSMB->AndXCommand = 0xFF;
3854         pSMB->Flags = cpu_to_le16(TCON_EXTENDED_SECINFO);
3855         bcc_ptr = &pSMB->Password[0];
3856         if (tcon->pipe || (ses->server->sec_mode & SECMODE_USER)) {
3857                 pSMB->PasswordLength = cpu_to_le16(1);  /* minimum */
3858                 *bcc_ptr = 0; /* password is null byte */
3859                 bcc_ptr++;              /* skip password */
3860                 /* already aligned so no need to do it below */
3861         }
3862
3863         if (ses->server->sign)
3864                 smb_buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
3865
3866         if (ses->capabilities & CAP_STATUS32) {
3867                 smb_buffer->Flags2 |= SMBFLG2_ERR_STATUS;
3868         }
3869         if (ses->capabilities & CAP_DFS) {
3870                 smb_buffer->Flags2 |= SMBFLG2_DFS;
3871         }
3872         if (ses->capabilities & CAP_UNICODE) {
3873                 smb_buffer->Flags2 |= SMBFLG2_UNICODE;
3874                 length =
3875                     cifs_strtoUTF16((__le16 *) bcc_ptr, tree,
3876                         6 /* max utf8 char length in bytes */ *
3877                         (/* server len*/ + 256 /* share len */), nls_codepage);
3878                 bcc_ptr += 2 * length;  /* convert num 16 bit words to bytes */
3879                 bcc_ptr += 2;   /* skip trailing null */
3880         } else {                /* ASCII */
3881                 strcpy(bcc_ptr, tree);
3882                 bcc_ptr += strlen(tree) + 1;
3883         }
3884         strcpy(bcc_ptr, "?????");
3885         bcc_ptr += strlen("?????");
3886         bcc_ptr += 1;
3887         count = bcc_ptr - &pSMB->Password[0];
3888         be32_add_cpu(&pSMB->hdr.smb_buf_length, count);
3889         pSMB->ByteCount = cpu_to_le16(count);
3890
3891         rc = SendReceive(xid, ses, smb_buffer, smb_buffer_response, &length,
3892                          0);
3893
3894         /* above now done in SendReceive */
3895         if (rc == 0) {
3896                 bool is_unicode;
3897
3898                 tcon->tid = smb_buffer_response->Tid;
3899                 bcc_ptr = pByteArea(smb_buffer_response);
3900                 bytes_left = get_bcc(smb_buffer_response);
3901                 length = strnlen(bcc_ptr, bytes_left - 2);
3902                 if (smb_buffer->Flags2 & SMBFLG2_UNICODE)
3903                         is_unicode = true;
3904                 else
3905                         is_unicode = false;
3906
3907
3908                 /* skip service field (NB: this field is always ASCII) */
3909                 if (length == 3) {
3910                         if ((bcc_ptr[0] == 'I') && (bcc_ptr[1] == 'P') &&
3911                             (bcc_ptr[2] == 'C')) {
3912                                 cifs_dbg(FYI, "IPC connection\n");
3913                                 tcon->ipc = true;
3914                                 tcon->pipe = true;
3915                         }
3916                 } else if (length == 2) {
3917                         if ((bcc_ptr[0] == 'A') && (bcc_ptr[1] == ':')) {
3918                                 /* the most common case */
3919                                 cifs_dbg(FYI, "disk share connection\n");
3920                         }
3921                 }
3922                 bcc_ptr += length + 1;
3923                 bytes_left -= (length + 1);
3924                 strlcpy(tcon->treeName, tree, sizeof(tcon->treeName));
3925
3926                 /* mostly informational -- no need to fail on error here */
3927                 kfree(tcon->nativeFileSystem);
3928                 tcon->nativeFileSystem = cifs_strndup_from_utf16(bcc_ptr,
3929                                                       bytes_left, is_unicode,
3930                                                       nls_codepage);
3931
3932                 cifs_dbg(FYI, "nativeFileSystem=%s\n", tcon->nativeFileSystem);
3933
3934                 if ((smb_buffer_response->WordCount == 3) ||
3935                          (smb_buffer_response->WordCount == 7))
3936                         /* field is in same location */
3937                         tcon->Flags = le16_to_cpu(pSMBr->OptionalSupport);
3938                 else
3939                         tcon->Flags = 0;
3940                 cifs_dbg(FYI, "Tcon flags: 0x%x\n", tcon->Flags);
3941         }
3942
3943         cifs_buf_release(smb_buffer);
3944         return rc;
3945 }
3946
3947 static void delayed_free(struct rcu_head *p)
3948 {
3949         struct cifs_sb_info *cifs_sb = container_of(p, struct cifs_sb_info, rcu);
3950
3951         unload_nls(cifs_sb->local_nls);
3952         smb3_cleanup_fs_context(cifs_sb->ctx);
3953         kfree(cifs_sb);
3954 }
3955
3956 void
3957 cifs_umount(struct cifs_sb_info *cifs_sb)
3958 {
3959         struct rb_root *root = &cifs_sb->tlink_tree;
3960         struct rb_node *node;
3961         struct tcon_link *tlink;
3962
3963         cancel_delayed_work_sync(&cifs_sb->prune_tlinks);
3964
3965         spin_lock(&cifs_sb->tlink_tree_lock);
3966         while ((node = rb_first(root))) {
3967                 tlink = rb_entry(node, struct tcon_link, tl_rbnode);
3968                 cifs_get_tlink(tlink);
3969                 clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
3970                 rb_erase(node, root);
3971
3972                 spin_unlock(&cifs_sb->tlink_tree_lock);
3973                 cifs_put_tlink(tlink);
3974                 spin_lock(&cifs_sb->tlink_tree_lock);
3975         }
3976         spin_unlock(&cifs_sb->tlink_tree_lock);
3977
3978         kfree(cifs_sb->prepath);
3979 #ifdef CONFIG_CIFS_DFS_UPCALL
3980         dfs_cache_put_refsrv_sessions(&cifs_sb->dfs_mount_id);
3981 #endif
3982         call_rcu(&cifs_sb->rcu, delayed_free);
3983 }
3984
3985 int
3986 cifs_negotiate_protocol(const unsigned int xid, struct cifs_ses *ses,
3987                         struct TCP_Server_Info *server)
3988 {
3989         int rc = 0;
3990
3991         if (!server->ops->need_neg || !server->ops->negotiate)
3992                 return -ENOSYS;
3993
3994         /* only send once per connect */
3995         spin_lock(&cifs_tcp_ses_lock);
3996         if (!server->ops->need_neg(server) ||
3997             server->tcpStatus != CifsNeedNegotiate) {
3998                 spin_unlock(&cifs_tcp_ses_lock);
3999                 return 0;
4000         }
4001         server->tcpStatus = CifsInNegotiate;
4002         spin_unlock(&cifs_tcp_ses_lock);
4003
4004         rc = server->ops->negotiate(xid, ses, server);
4005         if (rc == 0) {
4006                 spin_lock(&cifs_tcp_ses_lock);
4007                 if (server->tcpStatus == CifsInNegotiate)
4008                         server->tcpStatus = CifsGood;
4009                 else
4010                         rc = -EHOSTDOWN;
4011                 spin_unlock(&cifs_tcp_ses_lock);
4012         } else {
4013                 spin_lock(&cifs_tcp_ses_lock);
4014                 if (server->tcpStatus == CifsInNegotiate)
4015                         server->tcpStatus = CifsNeedNegotiate;
4016                 spin_unlock(&cifs_tcp_ses_lock);
4017         }
4018
4019         return rc;
4020 }
4021
4022 int
4023 cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
4024                    struct TCP_Server_Info *server,
4025                    struct nls_table *nls_info)
4026 {
4027         int rc = -ENOSYS;
4028         struct sockaddr_in6 *addr6 = (struct sockaddr_in6 *)&server->dstaddr;
4029         struct sockaddr_in *addr = (struct sockaddr_in *)&server->dstaddr;
4030         bool is_binding = false;
4031
4032         spin_lock(&cifs_tcp_ses_lock);
4033         if (server->dstaddr.ss_family == AF_INET6)
4034                 scnprintf(ses->ip_addr, sizeof(ses->ip_addr), "%pI6", &addr6->sin6_addr);
4035         else
4036                 scnprintf(ses->ip_addr, sizeof(ses->ip_addr), "%pI4", &addr->sin_addr);
4037
4038         if (ses->ses_status != SES_GOOD &&
4039             ses->ses_status != SES_NEW &&
4040             ses->ses_status != SES_NEED_RECON) {
4041                 spin_unlock(&cifs_tcp_ses_lock);
4042                 return 0;
4043         }
4044
4045         /* only send once per connect */
4046         spin_lock(&ses->chan_lock);
4047         if (CIFS_ALL_CHANS_GOOD(ses) ||
4048             cifs_chan_in_reconnect(ses, server)) {
4049                 spin_unlock(&ses->chan_lock);
4050                 spin_unlock(&cifs_tcp_ses_lock);
4051                 return 0;
4052         }
4053         is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
4054         cifs_chan_set_in_reconnect(ses, server);
4055         spin_unlock(&ses->chan_lock);
4056
4057         if (!is_binding)
4058                 ses->ses_status = SES_IN_SETUP;
4059         spin_unlock(&cifs_tcp_ses_lock);
4060
4061         if (!is_binding) {
4062                 ses->capabilities = server->capabilities;
4063                 if (!linuxExtEnabled)
4064                         ses->capabilities &= (~server->vals->cap_unix);
4065
4066                 if (ses->auth_key.response) {
4067                         cifs_dbg(FYI, "Free previous auth_key.response = %p\n",
4068                                  ses->auth_key.response);
4069                         kfree(ses->auth_key.response);
4070                         ses->auth_key.response = NULL;
4071                         ses->auth_key.len = 0;
4072                 }
4073         }
4074
4075         cifs_dbg(FYI, "Security Mode: 0x%x Capabilities: 0x%x TimeAdjust: %d\n",
4076                  server->sec_mode, server->capabilities, server->timeAdj);
4077
4078         if (server->ops->sess_setup)
4079                 rc = server->ops->sess_setup(xid, ses, server, nls_info);
4080
4081         if (rc) {
4082                 cifs_server_dbg(VFS, "Send error in SessSetup = %d\n", rc);
4083                 spin_lock(&cifs_tcp_ses_lock);
4084                 if (ses->ses_status == SES_IN_SETUP)
4085                         ses->ses_status = SES_NEED_RECON;
4086                 spin_lock(&ses->chan_lock);
4087                 cifs_chan_clear_in_reconnect(ses, server);
4088                 spin_unlock(&ses->chan_lock);
4089                 spin_unlock(&cifs_tcp_ses_lock);
4090         } else {
4091                 spin_lock(&cifs_tcp_ses_lock);
4092                 if (ses->ses_status == SES_IN_SETUP)
4093                         ses->ses_status = SES_GOOD;
4094                 spin_lock(&ses->chan_lock);
4095                 cifs_chan_clear_in_reconnect(ses, server);
4096                 cifs_chan_clear_need_reconnect(ses, server);
4097                 spin_unlock(&ses->chan_lock);
4098                 spin_unlock(&cifs_tcp_ses_lock);
4099         }
4100
4101         return rc;
4102 }
4103
4104 static int
4105 cifs_set_vol_auth(struct smb3_fs_context *ctx, struct cifs_ses *ses)
4106 {
4107         ctx->sectype = ses->sectype;
4108
4109         /* krb5 is special, since we don't need username or pw */
4110         if (ctx->sectype == Kerberos)
4111                 return 0;
4112
4113         return cifs_set_cifscreds(ctx, ses);
4114 }
4115
4116 static struct cifs_tcon *
4117 cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
4118 {
4119         int rc;
4120         struct cifs_tcon *master_tcon = cifs_sb_master_tcon(cifs_sb);
4121         struct cifs_ses *ses;
4122         struct cifs_tcon *tcon = NULL;
4123         struct smb3_fs_context *ctx;
4124
4125         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
4126         if (ctx == NULL)
4127                 return ERR_PTR(-ENOMEM);
4128
4129         ctx->local_nls = cifs_sb->local_nls;
4130         ctx->linux_uid = fsuid;
4131         ctx->cred_uid = fsuid;
4132         ctx->UNC = master_tcon->treeName;
4133         ctx->retry = master_tcon->retry;
4134         ctx->nocase = master_tcon->nocase;
4135         ctx->nohandlecache = master_tcon->nohandlecache;
4136         ctx->local_lease = master_tcon->local_lease;
4137         ctx->no_lease = master_tcon->no_lease;
4138         ctx->resilient = master_tcon->use_resilient;
4139         ctx->persistent = master_tcon->use_persistent;
4140         ctx->handle_timeout = master_tcon->handle_timeout;
4141         ctx->no_linux_ext = !master_tcon->unix_ext;
4142         ctx->linux_ext = master_tcon->posix_extensions;
4143         ctx->sectype = master_tcon->ses->sectype;
4144         ctx->sign = master_tcon->ses->sign;
4145         ctx->seal = master_tcon->seal;
4146         ctx->witness = master_tcon->use_witness;
4147
4148         rc = cifs_set_vol_auth(ctx, master_tcon->ses);
4149         if (rc) {
4150                 tcon = ERR_PTR(rc);
4151                 goto out;
4152         }
4153
4154         /* get a reference for the same TCP session */
4155         spin_lock(&cifs_tcp_ses_lock);
4156         ++master_tcon->ses->server->srv_count;
4157         spin_unlock(&cifs_tcp_ses_lock);
4158
4159         ses = cifs_get_smb_ses(master_tcon->ses->server, ctx);
4160         if (IS_ERR(ses)) {
4161                 tcon = (struct cifs_tcon *)ses;
4162                 cifs_put_tcp_session(master_tcon->ses->server, 0);
4163                 goto out;
4164         }
4165
4166         tcon = cifs_get_tcon(ses, ctx);
4167         if (IS_ERR(tcon)) {
4168                 cifs_put_smb_ses(ses);
4169                 goto out;
4170         }
4171
4172         if (cap_unix(ses))
4173                 reset_cifs_unix_caps(0, tcon, NULL, ctx);
4174
4175 out:
4176         kfree(ctx->username);
4177         kfree_sensitive(ctx->password);
4178         kfree(ctx);
4179
4180         return tcon;
4181 }
4182
4183 struct cifs_tcon *
4184 cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
4185 {
4186         return tlink_tcon(cifs_sb_master_tlink(cifs_sb));
4187 }
4188
4189 /* find and return a tlink with given uid */
4190 static struct tcon_link *
4191 tlink_rb_search(struct rb_root *root, kuid_t uid)
4192 {
4193         struct rb_node *node = root->rb_node;
4194         struct tcon_link *tlink;
4195
4196         while (node) {
4197                 tlink = rb_entry(node, struct tcon_link, tl_rbnode);
4198
4199                 if (uid_gt(tlink->tl_uid, uid))
4200                         node = node->rb_left;
4201                 else if (uid_lt(tlink->tl_uid, uid))
4202                         node = node->rb_right;
4203                 else
4204                         return tlink;
4205         }
4206         return NULL;
4207 }
4208
4209 /* insert a tcon_link into the tree */
4210 static void
4211 tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink)
4212 {
4213         struct rb_node **new = &(root->rb_node), *parent = NULL;
4214         struct tcon_link *tlink;
4215
4216         while (*new) {
4217                 tlink = rb_entry(*new, struct tcon_link, tl_rbnode);
4218                 parent = *new;
4219
4220                 if (uid_gt(tlink->tl_uid, new_tlink->tl_uid))
4221                         new = &((*new)->rb_left);
4222                 else
4223                         new = &((*new)->rb_right);
4224         }
4225
4226         rb_link_node(&new_tlink->tl_rbnode, parent, new);
4227         rb_insert_color(&new_tlink->tl_rbnode, root);
4228 }
4229
4230 /*
4231  * Find or construct an appropriate tcon given a cifs_sb and the fsuid of the
4232  * current task.
4233  *
4234  * If the superblock doesn't refer to a multiuser mount, then just return
4235  * the master tcon for the mount.
4236  *
4237  * First, search the rbtree for an existing tcon for this fsuid. If one
4238  * exists, then check to see if it's pending construction. If it is then wait
4239  * for construction to complete. Once it's no longer pending, check to see if
4240  * it failed and either return an error or retry construction, depending on
4241  * the timeout.
4242  *
4243  * If one doesn't exist then insert a new tcon_link struct into the tree and
4244  * try to construct a new one.
4245  */
4246 struct tcon_link *
4247 cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
4248 {
4249         int ret;
4250         kuid_t fsuid = current_fsuid();
4251         struct tcon_link *tlink, *newtlink;
4252
4253         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MULTIUSER))
4254                 return cifs_get_tlink(cifs_sb_master_tlink(cifs_sb));
4255
4256         spin_lock(&cifs_sb->tlink_tree_lock);
4257         tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4258         if (tlink)
4259                 cifs_get_tlink(tlink);
4260         spin_unlock(&cifs_sb->tlink_tree_lock);
4261
4262         if (tlink == NULL) {
4263                 newtlink = kzalloc(sizeof(*tlink), GFP_KERNEL);
4264                 if (newtlink == NULL)
4265                         return ERR_PTR(-ENOMEM);
4266                 newtlink->tl_uid = fsuid;
4267                 newtlink->tl_tcon = ERR_PTR(-EACCES);
4268                 set_bit(TCON_LINK_PENDING, &newtlink->tl_flags);
4269                 set_bit(TCON_LINK_IN_TREE, &newtlink->tl_flags);
4270                 cifs_get_tlink(newtlink);
4271
4272                 spin_lock(&cifs_sb->tlink_tree_lock);
4273                 /* was one inserted after previous search? */
4274                 tlink = tlink_rb_search(&cifs_sb->tlink_tree, fsuid);
4275                 if (tlink) {
4276                         cifs_get_tlink(tlink);
4277                         spin_unlock(&cifs_sb->tlink_tree_lock);
4278                         kfree(newtlink);
4279                         goto wait_for_construction;
4280                 }
4281                 tlink = newtlink;
4282                 tlink_rb_insert(&cifs_sb->tlink_tree, tlink);
4283                 spin_unlock(&cifs_sb->tlink_tree_lock);
4284         } else {
4285 wait_for_construction:
4286                 ret = wait_on_bit(&tlink->tl_flags, TCON_LINK_PENDING,
4287                                   TASK_INTERRUPTIBLE);
4288                 if (ret) {
4289                         cifs_put_tlink(tlink);
4290                         return ERR_PTR(-ERESTARTSYS);
4291                 }
4292
4293                 /* if it's good, return it */
4294                 if (!IS_ERR(tlink->tl_tcon))
4295                         return tlink;
4296
4297                 /* return error if we tried this already recently */
4298                 if (time_before(jiffies, tlink->tl_time + TLINK_ERROR_EXPIRE)) {
4299                         cifs_put_tlink(tlink);
4300                         return ERR_PTR(-EACCES);
4301                 }
4302
4303                 if (test_and_set_bit(TCON_LINK_PENDING, &tlink->tl_flags))
4304                         goto wait_for_construction;
4305         }
4306
4307         tlink->tl_tcon = cifs_construct_tcon(cifs_sb, fsuid);
4308         clear_bit(TCON_LINK_PENDING, &tlink->tl_flags);
4309         wake_up_bit(&tlink->tl_flags, TCON_LINK_PENDING);
4310
4311         if (IS_ERR(tlink->tl_tcon)) {
4312                 cifs_put_tlink(tlink);
4313                 return ERR_PTR(-EACCES);
4314         }
4315
4316         return tlink;
4317 }
4318
4319 /*
4320  * periodic workqueue job that scans tcon_tree for a superblock and closes
4321  * out tcons.
4322  */
4323 static void
4324 cifs_prune_tlinks(struct work_struct *work)
4325 {
4326         struct cifs_sb_info *cifs_sb = container_of(work, struct cifs_sb_info,
4327                                                     prune_tlinks.work);
4328         struct rb_root *root = &cifs_sb->tlink_tree;
4329         struct rb_node *node;
4330         struct rb_node *tmp;
4331         struct tcon_link *tlink;
4332
4333         /*
4334          * Because we drop the spinlock in the loop in order to put the tlink
4335          * it's not guarded against removal of links from the tree. The only
4336          * places that remove entries from the tree are this function and
4337          * umounts. Because this function is non-reentrant and is canceled
4338          * before umount can proceed, this is safe.
4339          */
4340         spin_lock(&cifs_sb->tlink_tree_lock);
4341         node = rb_first(root);
4342         while (node != NULL) {
4343                 tmp = node;
4344                 node = rb_next(tmp);
4345                 tlink = rb_entry(tmp, struct tcon_link, tl_rbnode);
4346
4347                 if (test_bit(TCON_LINK_MASTER, &tlink->tl_flags) ||
4348                     atomic_read(&tlink->tl_count) != 0 ||
4349                     time_after(tlink->tl_time + TLINK_IDLE_EXPIRE, jiffies))
4350                         continue;
4351
4352                 cifs_get_tlink(tlink);
4353                 clear_bit(TCON_LINK_IN_TREE, &tlink->tl_flags);
4354                 rb_erase(tmp, root);
4355
4356                 spin_unlock(&cifs_sb->tlink_tree_lock);
4357                 cifs_put_tlink(tlink);
4358                 spin_lock(&cifs_sb->tlink_tree_lock);
4359         }
4360         spin_unlock(&cifs_sb->tlink_tree_lock);
4361
4362         queue_delayed_work(cifsiod_wq, &cifs_sb->prune_tlinks,
4363                                 TLINK_IDLE_EXPIRE);
4364 }
4365
4366 #ifdef CONFIG_CIFS_DFS_UPCALL
4367 /* Update dfs referral path of superblock */
4368 static int update_server_fullpath(struct TCP_Server_Info *server, struct cifs_sb_info *cifs_sb,
4369                                   const char *target)
4370 {
4371         int rc = 0;
4372         size_t len = strlen(target);
4373         char *refpath, *npath;
4374
4375         if (unlikely(len < 2 || *target != '\\'))
4376                 return -EINVAL;
4377
4378         if (target[1] == '\\') {
4379                 len += 1;
4380                 refpath = kmalloc(len, GFP_KERNEL);
4381                 if (!refpath)
4382                         return -ENOMEM;
4383
4384                 scnprintf(refpath, len, "%s", target);
4385         } else {
4386                 len += sizeof("\\");
4387                 refpath = kmalloc(len, GFP_KERNEL);
4388                 if (!refpath)
4389                         return -ENOMEM;
4390
4391                 scnprintf(refpath, len, "\\%s", target);
4392         }
4393
4394         npath = dfs_cache_canonical_path(refpath, cifs_sb->local_nls, cifs_remap(cifs_sb));
4395         kfree(refpath);
4396
4397         if (IS_ERR(npath)) {
4398                 rc = PTR_ERR(npath);
4399         } else {
4400                 mutex_lock(&server->refpath_lock);
4401                 kfree(server->leaf_fullpath);
4402                 server->leaf_fullpath = npath;
4403                 mutex_unlock(&server->refpath_lock);
4404                 server->current_fullpath = server->leaf_fullpath;
4405         }
4406         return rc;
4407 }
4408
4409 static int target_share_matches_server(struct TCP_Server_Info *server, const char *tcp_host,
4410                                        size_t tcp_host_len, char *share, bool *target_match)
4411 {
4412         int rc = 0;
4413         const char *dfs_host;
4414         size_t dfs_host_len;
4415
4416         *target_match = true;
4417         extract_unc_hostname(share, &dfs_host, &dfs_host_len);
4418
4419         /* Check if hostnames or addresses match */
4420         if (dfs_host_len != tcp_host_len || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {
4421                 cifs_dbg(FYI, "%s: %.*s doesn't match %.*s\n", __func__, (int)dfs_host_len,
4422                          dfs_host, (int)tcp_host_len, tcp_host);
4423                 rc = match_target_ip(server, dfs_host, dfs_host_len, target_match);
4424                 if (rc)
4425                         cifs_dbg(VFS, "%s: failed to match target ip: %d\n", __func__, rc);
4426         }
4427         return rc;
4428 }
4429
4430 static int __tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tcon,
4431                                      struct cifs_sb_info *cifs_sb, char *tree, bool islink,
4432                                      struct dfs_cache_tgt_list *tl)
4433 {
4434         int rc;
4435         struct TCP_Server_Info *server = tcon->ses->server;
4436         const struct smb_version_operations *ops = server->ops;
4437         struct cifs_tcon *ipc = tcon->ses->tcon_ipc;
4438         char *share = NULL, *prefix = NULL;
4439         const char *tcp_host;
4440         size_t tcp_host_len;
4441         struct dfs_cache_tgt_iterator *tit;
4442         bool target_match;
4443
4444         extract_unc_hostname(server->hostname, &tcp_host, &tcp_host_len);
4445
4446         tit = dfs_cache_get_tgt_iterator(tl);
4447         if (!tit) {
4448                 rc = -ENOENT;
4449                 goto out;
4450         }
4451
4452         /* Try to tree connect to all dfs targets */
4453         for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
4454                 const char *target = dfs_cache_get_tgt_name(tit);
4455                 struct dfs_cache_tgt_list ntl = DFS_CACHE_TGT_LIST_INIT(ntl);
4456
4457                 kfree(share);
4458                 kfree(prefix);
4459                 share = prefix = NULL;
4460
4461                 /* Check if share matches with tcp ses */
4462                 rc = dfs_cache_get_tgt_share(server->current_fullpath + 1, tit, &share, &prefix);
4463                 if (rc) {
4464                         cifs_dbg(VFS, "%s: failed to parse target share: %d\n", __func__, rc);
4465                         break;
4466                 }
4467
4468                 rc = target_share_matches_server(server, tcp_host, tcp_host_len, share,
4469                                                  &target_match);
4470                 if (rc)
4471                         break;
4472                 if (!target_match) {
4473                         rc = -EHOSTUNREACH;
4474                         continue;
4475                 }
4476
4477                 if (ipc->need_reconnect) {
4478                         scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
4479                         rc = ops->tree_connect(xid, ipc->ses, tree, ipc, cifs_sb->local_nls);
4480                         if (rc)
4481                                 break;
4482                 }
4483
4484                 scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
4485                 if (!islink) {
4486                         rc = ops->tree_connect(xid, tcon->ses, tree, tcon, cifs_sb->local_nls);
4487                         break;
4488                 }
4489                 /*
4490                  * If no dfs referrals were returned from link target, then just do a TREE_CONNECT
4491                  * to it.  Otherwise, cache the dfs referral and then mark current tcp ses for
4492                  * reconnect so either the demultiplex thread or the echo worker will reconnect to
4493                  * newly resolved target.
4494                  */
4495                 if (dfs_cache_find(xid, tcon->ses, cifs_sb->local_nls, cifs_remap(cifs_sb), target,
4496                                    NULL, &ntl)) {
4497                         rc = ops->tree_connect(xid, tcon->ses, tree, tcon, cifs_sb->local_nls);
4498                         if (rc)
4499                                 continue;
4500                         rc = dfs_cache_noreq_update_tgthint(server->current_fullpath + 1, tit);
4501                         if (!rc)
4502                                 rc = cifs_update_super_prepath(cifs_sb, prefix);
4503                 } else {
4504                         /* Target is another dfs share */
4505                         rc = update_server_fullpath(server, cifs_sb, target);
4506                         dfs_cache_free_tgts(tl);
4507
4508                         if (!rc) {
4509                                 rc = -EREMOTE;
4510                                 list_replace_init(&ntl.tl_list, &tl->tl_list);
4511                         } else
4512                                 dfs_cache_free_tgts(&ntl);
4513                 }
4514                 break;
4515         }
4516
4517 out:
4518         kfree(share);
4519         kfree(prefix);
4520
4521         return rc;
4522 }
4523
4524 static int tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tcon,
4525                                    struct cifs_sb_info *cifs_sb, char *tree, bool islink,
4526                                    struct dfs_cache_tgt_list *tl)
4527 {
4528         int rc;
4529         int num_links = 0;
4530         struct TCP_Server_Info *server = tcon->ses->server;
4531
4532         do {
4533                 rc = __tree_connect_dfs_target(xid, tcon, cifs_sb, tree, islink, tl);
4534                 if (!rc || rc != -EREMOTE)
4535                         break;
4536         } while (rc = -ELOOP, ++num_links < MAX_NESTED_LINKS);
4537         /*
4538          * If we couldn't tree connect to any targets from last referral path, then retry from
4539          * original referral path.
4540          */
4541         if (rc && server->current_fullpath != server->origin_fullpath) {
4542                 server->current_fullpath = server->origin_fullpath;
4543                 cifs_signal_cifsd_for_reconnect(server, true);
4544         }
4545
4546         dfs_cache_free_tgts(tl);
4547         return rc;
4548 }
4549
4550 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
4551 {
4552         int rc;
4553         struct TCP_Server_Info *server = tcon->ses->server;
4554         const struct smb_version_operations *ops = server->ops;
4555         struct super_block *sb = NULL;
4556         struct cifs_sb_info *cifs_sb;
4557         struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl);
4558         char *tree;
4559         struct dfs_info3_param ref = {0};
4560
4561         /* only send once per connect */
4562         spin_lock(&cifs_tcp_ses_lock);
4563         if (tcon->ses->ses_status != SES_GOOD ||
4564             (tcon->status != TID_NEW &&
4565             tcon->status != TID_NEED_TCON)) {
4566                 spin_unlock(&cifs_tcp_ses_lock);
4567                 return 0;
4568         }
4569         tcon->status = TID_IN_TCON;
4570         spin_unlock(&cifs_tcp_ses_lock);
4571
4572         tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
4573         if (!tree) {
4574                 rc = -ENOMEM;
4575                 goto out;
4576         }
4577
4578         if (tcon->ipc) {
4579                 scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
4580                 rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
4581                 goto out;
4582         }
4583
4584         sb = cifs_get_tcp_super(server);
4585         if (IS_ERR(sb)) {
4586                 rc = PTR_ERR(sb);
4587                 cifs_dbg(VFS, "%s: could not find superblock: %d\n", __func__, rc);
4588                 goto out;
4589         }
4590
4591         cifs_sb = CIFS_SB(sb);
4592
4593         /* If it is not dfs or there was no cached dfs referral, then reconnect to same share */
4594         if (!server->current_fullpath ||
4595             dfs_cache_noreq_find(server->current_fullpath + 1, &ref, &tl)) {
4596                 rc = ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, cifs_sb->local_nls);
4597                 goto out;
4598         }
4599
4600         rc = tree_connect_dfs_target(xid, tcon, cifs_sb, tree, ref.server_type == DFS_TYPE_LINK,
4601                                      &tl);
4602         free_dfs_info_param(&ref);
4603
4604 out:
4605         kfree(tree);
4606         cifs_put_tcp_super(sb);
4607
4608         if (rc) {
4609                 spin_lock(&cifs_tcp_ses_lock);
4610                 if (tcon->status == TID_IN_TCON)
4611                         tcon->status = TID_NEED_TCON;
4612                 spin_unlock(&cifs_tcp_ses_lock);
4613         } else {
4614                 spin_lock(&cifs_tcp_ses_lock);
4615                 if (tcon->status == TID_IN_TCON)
4616                         tcon->status = TID_GOOD;
4617                 spin_unlock(&cifs_tcp_ses_lock);
4618                 tcon->need_reconnect = false;
4619         }
4620
4621         return rc;
4622 }
4623 #else
4624 int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
4625 {
4626         int rc;
4627         const struct smb_version_operations *ops = tcon->ses->server->ops;
4628
4629         /* only send once per connect */
4630         spin_lock(&cifs_tcp_ses_lock);
4631         if (tcon->ses->ses_status != SES_GOOD ||
4632             (tcon->status != TID_NEW &&
4633             tcon->status != TID_NEED_TCON)) {
4634                 spin_unlock(&cifs_tcp_ses_lock);
4635                 return 0;
4636         }
4637         tcon->status = TID_IN_TCON;
4638         spin_unlock(&cifs_tcp_ses_lock);
4639
4640         rc = ops->tree_connect(xid, tcon->ses, tcon->treeName, tcon, nlsc);
4641         if (rc) {
4642                 spin_lock(&cifs_tcp_ses_lock);
4643                 if (tcon->status == TID_IN_TCON)
4644                         tcon->status = TID_NEED_TCON;
4645                 spin_unlock(&cifs_tcp_ses_lock);
4646         } else {
4647                 spin_lock(&cifs_tcp_ses_lock);
4648                 if (tcon->status == TID_IN_TCON)
4649                         tcon->status = TID_GOOD;
4650                 spin_unlock(&cifs_tcp_ses_lock);
4651                 tcon->need_reconnect = false;
4652         }
4653
4654         return rc;
4655 }
4656 #endif