fs/smb/client/misc.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2008
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  */
   8
   9 #include <linux/slab.h>
  10 #include <linux/ctype.h>
  11 #include <linux/mempool.h>
  12 #include <linux/vmalloc.h>
  13 #include "cifspdu.h"
  14 #include "cifsglob.h"
  15 #include "cifsproto.h"
  16 #include "cifs_debug.h"
  17 #include "smberr.h"
  18 #include "nterr.h"
  19 #include "cifs_unicode.h"
  20 #include "smb2pdu.h"
  21 #include "cifsfs.h"
  22 #ifdef CONFIG_CIFS_DFS_UPCALL
  23 #include "dns_resolve.h"
  24 #include "dfs_cache.h"
  25 #include "dfs.h"
  26 #endif
  27 #include "fs_context.h"
  28 #include "cached_dir.h"
  29
  30 extern mempool_t *cifs_sm_req_poolp;
  31 extern mempool_t *cifs_req_poolp;
  32
  33 /* The xid serves as a useful identifier for each incoming vfs request,
  34    in a similar way to the mid which is useful to track each sent smb,
  35    and CurrentXid can also provide a running counter (although it
  36    will eventually wrap past zero) of the total vfs operations handled
  37    since the cifs fs was mounted */
  38
  39 unsigned int
  40 _get_xid(void)
  41 {
  42         unsigned int xid;
  43
  44         spin_lock(&GlobalMid_Lock);
  45         GlobalTotalActiveXid++;
  46
  47         /* keep high water mark for number of simultaneous ops in filesystem */
  48         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  49                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  50         if (GlobalTotalActiveXid > 65000)
  51                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  52         xid = GlobalCurrentXid++;
  53         spin_unlock(&GlobalMid_Lock);
  54         return xid;
  55 }
  56
  57 void
  58 _free_xid(unsigned int xid)
  59 {
  60         spin_lock(&GlobalMid_Lock);
  61         /* if (GlobalTotalActiveXid == 0)
  62                 BUG(); */
  63         GlobalTotalActiveXid--;
  64         spin_unlock(&GlobalMid_Lock);
  65 }
  66
  67 struct cifs_ses *
  68 sesInfoAlloc(void)
  69 {
  70         struct cifs_ses *ret_buf;
  71
  72         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  73         if (ret_buf) {
  74                 atomic_inc(&sesInfoAllocCount);
  75                 spin_lock_init(&ret_buf->ses_lock);
  76                 ret_buf->ses_status = SES_NEW;
  77                 ++ret_buf->ses_count;
  78                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  79                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  80                 mutex_init(&ret_buf->session_mutex);
  81                 spin_lock_init(&ret_buf->iface_lock);
  82                 INIT_LIST_HEAD(&ret_buf->iface_list);
  83                 spin_lock_init(&ret_buf->chan_lock);
  84         }
  85         return ret_buf;
  86 }
  87
  88 void
  89 sesInfoFree(struct cifs_ses *buf_to_free)
  90 {
  91         struct cifs_server_iface *iface = NULL, *niface = NULL;
  92
  93         if (buf_to_free == NULL) {
  94                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  95                 return;
  96         }
  97
  98         unload_nls(buf_to_free->local_nls);
  99         atomic_dec(&sesInfoAllocCount);
 100         kfree(buf_to_free->serverOS);
 101         kfree(buf_to_free->serverDomain);
 102         kfree(buf_to_free->serverNOS);
 103         kfree_sensitive(buf_to_free->password);
 104         kfree(buf_to_free->user_name);
 105         kfree(buf_to_free->domainName);
 106         kfree_sensitive(buf_to_free->auth_key.response);
 107         spin_lock(&buf_to_free->iface_lock);
 108         list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
 109                                  iface_head)
 110                 kref_put(&iface->refcount, release_iface);
 111         spin_unlock(&buf_to_free->iface_lock);
 112         kfree_sensitive(buf_to_free);
 113 }
 114
 115 struct cifs_tcon *
 116 tcon_info_alloc(bool dir_leases_enabled)
 117 {
 118         struct cifs_tcon *ret_buf;
 119
 120         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 121         if (!ret_buf)
 122                 return NULL;
 123
 124         if (dir_leases_enabled == true) {
 125                 ret_buf->cfids = init_cached_dirs();
 126                 if (!ret_buf->cfids) {
 127                         kfree(ret_buf);
 128                         return NULL;
 129                 }
 130         }
 131         /* else ret_buf->cfids is already set to NULL above */
 132
 133         atomic_inc(&tconInfoAllocCount);
 134         ret_buf->status = TID_NEW;
 135         ++ret_buf->tc_count;
 136         spin_lock_init(&ret_buf->tc_lock);
 137         INIT_LIST_HEAD(&ret_buf->openFileList);
 138         INIT_LIST_HEAD(&ret_buf->tcon_list);
 139         spin_lock_init(&ret_buf->open_file_lock);
 140         spin_lock_init(&ret_buf->stat_lock);
 141         atomic_set(&ret_buf->num_local_opens, 0);
 142         atomic_set(&ret_buf->num_remote_opens, 0);
 143         ret_buf->stats_from_time = ktime_get_real_seconds();
 144 #ifdef CONFIG_CIFS_DFS_UPCALL
 145         INIT_LIST_HEAD(&ret_buf->dfs_ses_list);
 146 #endif
 147
 148         return ret_buf;
 149 }
 150
 151 void
 152 tconInfoFree(struct cifs_tcon *tcon)
 153 {
 154         if (tcon == NULL) {
 155                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 156                 return;
 157         }
 158         free_cached_dirs(tcon->cfids);
 159         atomic_dec(&tconInfoAllocCount);
 160         kfree(tcon->nativeFileSystem);
 161         kfree_sensitive(tcon->password);
 162 #ifdef CONFIG_CIFS_DFS_UPCALL
 163         dfs_put_root_smb_sessions(&tcon->dfs_ses_list);
 164 #endif
 165         kfree(tcon->origin_fullpath);
 166         kfree(tcon);
 167 }
 168
 169 struct smb_hdr *
 170 cifs_buf_get(void)
 171 {
 172         struct smb_hdr *ret_buf = NULL;
 173         /*
 174          * SMB2 header is bigger than CIFS one - no problems to clean some
 175          * more bytes for CIFS.
 176          */
 177         size_t buf_size = sizeof(struct smb2_hdr);
 178
 179         /*
 180          * We could use negotiated size instead of max_msgsize -
 181          * but it may be more efficient to always alloc same size
 182          * albeit slightly larger than necessary and maxbuffersize
 183          * defaults to this and can not be bigger.
 184          */
 185         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 186
 187         /* clear the first few header bytes */
 188         /* for most paths, more is cleared in header_assemble */
 189         memset(ret_buf, 0, buf_size + 3);
 190         atomic_inc(&buf_alloc_count);
 191 #ifdef CONFIG_CIFS_STATS2
 192         atomic_inc(&total_buf_alloc_count);
 193 #endif /* CONFIG_CIFS_STATS2 */
 194
 195         return ret_buf;
 196 }
 197
 198 void
 199 cifs_buf_release(void *buf_to_free)
 200 {
 201         if (buf_to_free == NULL) {
 202                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 203                 return;
 204         }
 205         mempool_free(buf_to_free, cifs_req_poolp);
 206
 207         atomic_dec(&buf_alloc_count);
 208         return;
 209 }
 210
 211 struct smb_hdr *
 212 cifs_small_buf_get(void)
 213 {
 214         struct smb_hdr *ret_buf = NULL;
 215
 216 /* We could use negotiated size instead of max_msgsize -
 217    but it may be more efficient to always alloc same size
 218    albeit slightly larger than necessary and maxbuffersize
 219    defaults to this and can not be bigger */
 220         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 221         /* No need to clear memory here, cleared in header assemble */
 222         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 223         atomic_inc(&small_buf_alloc_count);
 224 #ifdef CONFIG_CIFS_STATS2
 225         atomic_inc(&total_small_buf_alloc_count);
 226 #endif /* CONFIG_CIFS_STATS2 */
 227
 228         return ret_buf;
 229 }
 230
 231 void
 232 cifs_small_buf_release(void *buf_to_free)
 233 {
 234
 235         if (buf_to_free == NULL) {
 236                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 237                 return;
 238         }
 239         mempool_free(buf_to_free, cifs_sm_req_poolp);
 240
 241         atomic_dec(&small_buf_alloc_count);
 242         return;
 243 }
 244
 245 void
 246 free_rsp_buf(int resp_buftype, void *rsp)
 247 {
 248         if (resp_buftype == CIFS_SMALL_BUFFER)
 249                 cifs_small_buf_release(rsp);
 250         else if (resp_buftype == CIFS_LARGE_BUFFER)
 251                 cifs_buf_release(rsp);
 252 }
 253
 254 /* NB: MID can not be set if treeCon not passed in, in that
 255    case it is responsbility of caller to set the mid */
 256 void
 257 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 258                 const struct cifs_tcon *treeCon, int word_count
 259                 /* length of fixed section (word count) in two byte units  */)
 260 {
 261         char *temp = (char *) buffer;
 262
 263         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 264
 265         buffer->smb_buf_length = cpu_to_be32(
 266             (2 * word_count) + sizeof(struct smb_hdr) -
 267             4 /*  RFC 1001 length field does not count */  +
 268             2 /* for bcc field itself */) ;
 269
 270         buffer->Protocol[0] = 0xFF;
 271         buffer->Protocol[1] = 'S';
 272         buffer->Protocol[2] = 'M';
 273         buffer->Protocol[3] = 'B';
 274         buffer->Command = smb_command;
 275         buffer->Flags = 0x00;   /* case sensitive */
 276         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 277         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 278         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 279         if (treeCon) {
 280                 buffer->Tid = treeCon->tid;
 281                 if (treeCon->ses) {
 282                         if (treeCon->ses->capabilities & CAP_UNICODE)
 283                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 284                         if (treeCon->ses->capabilities & CAP_STATUS32)
 285                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 286
 287                         /* Uid is not converted */
 288                         buffer->Uid = treeCon->ses->Suid;
 289                         if (treeCon->ses->server)
 290                                 buffer->Mid = get_next_mid(treeCon->ses->server);
 291                 }
 292                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 293                         buffer->Flags2 |= SMBFLG2_DFS;
 294                 if (treeCon->nocase)
 295                         buffer->Flags  |= SMBFLG_CASELESS;
 296                 if ((treeCon->ses) && (treeCon->ses->server))
 297                         if (treeCon->ses->server->sign)
 298                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 299         }
 300
 301 /*  endian conversion of flags is now done just before sending */
 302         buffer->WordCount = (char) word_count;
 303         return;
 304 }
 305
 306 static int
 307 check_smb_hdr(struct smb_hdr *smb)
 308 {
 309         /* does it have the right SMB "signature" ? */
 310         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 311                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 312                          *(unsigned int *)smb->Protocol);
 313                 return 1;
 314         }
 315
 316         /* if it's a response then accept */
 317         if (smb->Flags & SMBFLG_RESPONSE)
 318                 return 0;
 319
 320         /* only one valid case where server sends us request */
 321         if (smb->Command == SMB_COM_LOCKING_ANDX)
 322                 return 0;
 323
 324         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 325                  get_mid(smb));
 326         return 1;
 327 }
 328
 329 int
 330 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 331 {
 332         struct smb_hdr *smb = (struct smb_hdr *)buf;
 333         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 334         __u32 clc_len;  /* calculated length */
 335         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 336                  total_read, rfclen);
 337
 338         /* is this frame too small to even get to a BCC? */
 339         if (total_read < 2 + sizeof(struct smb_hdr)) {
 340                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 341                             && (smb->Status.CifsError != 0)) {
 342                         /* it's an error return */
 343                         smb->WordCount = 0;
 344                         /* some error cases do not return wct and bcc */
 345                         return 0;
 346                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 347                                 (smb->WordCount == 0)) {
 348                         char *tmp = (char *)smb;
 349                         /* Need to work around a bug in two servers here */
 350                         /* First, check if the part of bcc they sent was zero */
 351                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 352                                 /* some servers return only half of bcc
 353                                  * on simple responses (wct, bcc both zero)
 354                                  * in particular have seen this on
 355                                  * ulogoffX and FindClose. This leaves
 356                                  * one byte of bcc potentially unitialized
 357                                  */
 358                                 /* zero rest of bcc */
 359                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 360                                 return 0;
 361                         }
 362                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 363                 } else {
 364                         cifs_dbg(VFS, "Length less than smb header size\n");
 365                 }
 366                 return -EIO;
 367         } else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
 368                 cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
 369                          __func__, smb->WordCount);
 370                 return -EIO;
 371         }
 372
 373         /* otherwise, there is enough to get to the BCC */
 374         if (check_smb_hdr(smb))
 375                 return -EIO;
 376         clc_len = smbCalcSize(smb);
 377
 378         if (4 + rfclen != total_read) {
 379                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 380                          rfclen);
 381                 return -EIO;
 382         }
 383
 384         if (4 + rfclen != clc_len) {
 385                 __u16 mid = get_mid(smb);
 386                 /* check if bcc wrapped around for large read responses */
 387                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 388                         /* check if lengths match mod 64K */
 389                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 390                                 return 0; /* bcc wrapped */
 391                 }
 392                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 393                          clc_len, 4 + rfclen, mid);
 394
 395                 if (4 + rfclen < clc_len) {
 396                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 397                                  rfclen, mid);
 398                         return -EIO;
 399                 } else if (rfclen > clc_len + 512) {
 400                         /*
 401                          * Some servers (Windows XP in particular) send more
 402                          * data than the lengths in the SMB packet would
 403                          * indicate on certain calls (byte range locks and
 404                          * trans2 find first calls in particular). While the
 405                          * client can handle such a frame by ignoring the
 406                          * trailing data, we choose limit the amount of extra
 407                          * data to 512 bytes.
 408                          */
 409                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 410                                  rfclen, mid);
 411                         return -EIO;
 412                 }
 413         }
 414         return 0;
 415 }
 416
 417 bool
 418 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 419 {
 420         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 421         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 422         struct TCP_Server_Info *pserver;
 423         struct cifs_ses *ses;
 424         struct cifs_tcon *tcon;
 425         struct cifsInodeInfo *pCifsInode;
 426         struct cifsFileInfo *netfile;
 427
 428         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 429         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 430            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 431                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 432                         (struct smb_com_transaction_change_notify_rsp *)buf;
 433                 struct file_notify_information *pnotify;
 434                 __u32 data_offset = 0;
 435                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 436
 437                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 438                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 439
 440                         if (data_offset >
 441                             len - sizeof(struct file_notify_information)) {
 442                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
 443                                          data_offset);
 444                                 return true;
 445                         }
 446                         pnotify = (struct file_notify_information *)
 447                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 448                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 449                                  pnotify->FileName, pnotify->Action);
 450                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 451                                 sizeof(struct smb_hdr)+60); */
 452                         return true;
 453                 }
 454                 if (pSMBr->hdr.Status.CifsError) {
 455                         cifs_dbg(FYI, "notify err 0x%x\n",
 456                                  pSMBr->hdr.Status.CifsError);
 457                         return true;
 458                 }
 459                 return false;
 460         }
 461         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 462                 return false;
 463         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 464                 /* no sense logging error on invalid handle on oplock
 465                    break - harmless race between close request and oplock
 466                    break response is expected from time to time writing out
 467                    large dirty files cached on the client */
 468                 if ((NT_STATUS_INVALID_HANDLE) ==
 469                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 470                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
 471                         return true;
 472                 } else if (ERRbadfid ==
 473                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 474                         return true;
 475                 } else {
 476                         return false; /* on valid oplock brk we get "request" */
 477                 }
 478         }
 479         if (pSMB->hdr.WordCount != 8)
 480                 return false;
 481
 482         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 483                  pSMB->LockType, pSMB->OplockLevel);
 484         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 485                 return false;
 486
 487         /* If server is a channel, select the primary channel */
 488         pserver = SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
 489
 490         /* look up tcon based on tid & uid */
 491         spin_lock(&cifs_tcp_ses_lock);
 492         list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 493                 if (cifs_ses_exiting(ses))
 494                         continue;
 495                 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 496                         if (tcon->tid != buf->Tid)
 497                                 continue;
 498
 499                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 500                         spin_lock(&tcon->open_file_lock);
 501                         list_for_each_entry(netfile, &tcon->openFileList, tlist) {
 502                                 if (pSMB->Fid != netfile->fid.netfid)
 503                                         continue;
 504
 505                                 cifs_dbg(FYI, "file id match, oplock break\n");
 506                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 507
 508                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 509                                         &pCifsInode->flags);
 510
 511                                 netfile->oplock_epoch = 0;
 512                                 netfile->oplock_level = pSMB->OplockLevel;
 513                                 netfile->oplock_break_cancelled = false;
 514                                 cifs_queue_oplock_break(netfile);
 515
 516                                 spin_unlock(&tcon->open_file_lock);
 517                                 spin_unlock(&cifs_tcp_ses_lock);
 518                                 return true;
 519                         }
 520                         spin_unlock(&tcon->open_file_lock);
 521                         spin_unlock(&cifs_tcp_ses_lock);
 522                         cifs_dbg(FYI, "No matching file for oplock break\n");
 523                         return true;
 524                 }
 525         }
 526         spin_unlock(&cifs_tcp_ses_lock);
 527         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 528         return true;
 529 }
 530
 531 void
 532 dump_smb(void *buf, int smb_buf_length)
 533 {
 534         if (traceSMB == 0)
 535                 return;
 536
 537         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 538                        smb_buf_length, true);
 539 }
 540
 541 void
 542 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 543 {
 544         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 545                 struct cifs_tcon *tcon = NULL;
 546
 547                 if (cifs_sb->master_tlink)
 548                         tcon = cifs_sb_master_tcon(cifs_sb);
 549
 550                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 551                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
 552                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 553                          tcon ? tcon->tree_name : "new server");
 554                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 555                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 556
 557         }
 558 }
 559
 560 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 561 {
 562         oplock &= 0xF;
 563
 564         if (oplock == OPLOCK_EXCLUSIVE) {
 565                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 566                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 567                          &cinode->netfs.inode);
 568         } else if (oplock == OPLOCK_READ) {
 569                 cinode->oplock = CIFS_CACHE_READ_FLG;
 570                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 571                          &cinode->netfs.inode);
 572         } else
 573                 cinode->oplock = 0;
 574 }
 575
 576 /*
 577  * We wait for oplock breaks to be processed before we attempt to perform
 578  * writes.
 579  */
 580 int cifs_get_writer(struct cifsInodeInfo *cinode)
 581 {
 582         int rc;
 583
 584 start:
 585         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 586                          TASK_KILLABLE);
 587         if (rc)
 588                 return rc;
 589
 590         spin_lock(&cinode->writers_lock);
 591         if (!cinode->writers)
 592                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 593         cinode->writers++;
 594         /* Check to see if we have started servicing an oplock break */
 595         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 596                 cinode->writers--;
 597                 if (cinode->writers == 0) {
 598                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 599                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 600                 }
 601                 spin_unlock(&cinode->writers_lock);
 602                 goto start;
 603         }
 604         spin_unlock(&cinode->writers_lock);
 605         return 0;
 606 }
 607
 608 void cifs_put_writer(struct cifsInodeInfo *cinode)
 609 {
 610         spin_lock(&cinode->writers_lock);
 611         cinode->writers--;
 612         if (cinode->writers == 0) {
 613                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 614                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 615         }
 616         spin_unlock(&cinode->writers_lock);
 617 }
 618
 619 /**
 620  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 621  * @cfile: The file to break the oplock on
 622  *
 623  * This function is called from the demultiplex thread when it
 624  * receives an oplock break for @cfile.
 625  *
 626  * Assumes the tcon->open_file_lock is held.
 627  * Assumes cfile->file_info_lock is NOT held.
 628  */
 629 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 630 {
 631         /*
 632          * Bump the handle refcount now while we hold the
 633          * open_file_lock to enforce the validity of it for the oplock
 634          * break handler. The matching put is done at the end of the
 635          * handler.
 636          */
 637         cifsFileInfo_get(cfile);
 638
 639         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 640 }
 641
 642 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 643 {
 644         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 645         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 646 }
 647
 648 bool
 649 backup_cred(struct cifs_sb_info *cifs_sb)
 650 {
 651         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 652                 if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
 653                         return true;
 654         }
 655         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 656                 if (in_group_p(cifs_sb->ctx->backupgid))
 657                         return true;
 658         }
 659
 660         return false;
 661 }
 662
 663 void
 664 cifs_del_pending_open(struct cifs_pending_open *open)
 665 {
 666         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 667         list_del(&open->olist);
 668         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 669 }
 670
 671 void
 672 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 673                              struct cifs_pending_open *open)
 674 {
 675         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 676         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 677         open->tlink = tlink;
 678         fid->pending_open = open;
 679         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 680 }
 681
 682 void
 683 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 684                       struct cifs_pending_open *open)
 685 {
 686         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 687         cifs_add_pending_open_locked(fid, tlink, open);
 688         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 689 }
 690
 691 /*
 692  * Critical section which runs after acquiring deferred_lock.
 693  * As there is no reference count on cifs_deferred_close, pdclose
 694  * should not be used outside deferred_lock.
 695  */
 696 bool
 697 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
 698 {
 699         struct cifs_deferred_close *dclose;
 700
 701         list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
 702                 if ((dclose->netfid == cfile->fid.netfid) &&
 703                         (dclose->persistent_fid == cfile->fid.persistent_fid) &&
 704                         (dclose->volatile_fid == cfile->fid.volatile_fid)) {
 705                         *pdclose = dclose;
 706                         return true;
 707                 }
 708         }
 709         return false;
 710 }
 711
 712 /*
 713  * Critical section which runs after acquiring deferred_lock.
 714  */
 715 void
 716 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
 717 {
 718         bool is_deferred = false;
 719         struct cifs_deferred_close *pdclose;
 720
 721         is_deferred = cifs_is_deferred_close(cfile, &pdclose);
 722         if (is_deferred) {
 723                 kfree(dclose);
 724                 return;
 725         }
 726
 727         dclose->tlink = cfile->tlink;
 728         dclose->netfid = cfile->fid.netfid;
 729         dclose->persistent_fid = cfile->fid.persistent_fid;
 730         dclose->volatile_fid = cfile->fid.volatile_fid;
 731         list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
 732 }
 733
 734 /*
 735  * Critical section which runs after acquiring deferred_lock.
 736  */
 737 void
 738 cifs_del_deferred_close(struct cifsFileInfo *cfile)
 739 {
 740         bool is_deferred = false;
 741         struct cifs_deferred_close *dclose;
 742
 743         is_deferred = cifs_is_deferred_close(cfile, &dclose);
 744         if (!is_deferred)
 745                 return;
 746         list_del(&dclose->dlist);
 747         kfree(dclose);
 748 }
 749
 750 void
 751 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
 752 {
 753         struct cifsFileInfo *cfile = NULL;
 754         struct file_list *tmp_list, *tmp_next_list;
 755         struct list_head file_head;
 756
 757         if (cifs_inode == NULL)
 758                 return;
 759
 760         INIT_LIST_HEAD(&file_head);
 761         spin_lock(&cifs_inode->open_file_lock);
 762         list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
 763                 if (delayed_work_pending(&cfile->deferred)) {
 764                         if (cancel_delayed_work(&cfile->deferred)) {
 765                                 spin_lock(&cifs_inode->deferred_lock);
 766                                 cifs_del_deferred_close(cfile);
 767                                 spin_unlock(&cifs_inode->deferred_lock);
 768
 769                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 770                                 if (tmp_list == NULL)
 771                                         break;
 772                                 tmp_list->cfile = cfile;
 773                                 list_add_tail(&tmp_list->list, &file_head);
 774                         }
 775                 }
 776         }
 777         spin_unlock(&cifs_inode->open_file_lock);
 778
 779         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 780                 _cifsFileInfo_put(tmp_list->cfile, false, false);
 781                 list_del(&tmp_list->list);
 782                 kfree(tmp_list);
 783         }
 784 }
 785
 786 void
 787 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
 788 {
 789         struct cifsFileInfo *cfile;
 790         struct file_list *tmp_list, *tmp_next_list;
 791         struct list_head file_head;
 792
 793         INIT_LIST_HEAD(&file_head);
 794         spin_lock(&tcon->open_file_lock);
 795         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 796                 if (delayed_work_pending(&cfile->deferred)) {
 797                         if (cancel_delayed_work(&cfile->deferred)) {
 798                                 spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 799                                 cifs_del_deferred_close(cfile);
 800                                 spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 801
 802                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 803                                 if (tmp_list == NULL)
 804                                         break;
 805                                 tmp_list->cfile = cfile;
 806                                 list_add_tail(&tmp_list->list, &file_head);
 807                         }
 808                 }
 809         }
 810         spin_unlock(&tcon->open_file_lock);
 811
 812         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 813                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 814                 list_del(&tmp_list->list);
 815                 kfree(tmp_list);
 816         }
 817 }
 818 void
 819 cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
 820 {
 821         struct cifsFileInfo *cfile;
 822         struct file_list *tmp_list, *tmp_next_list;
 823         struct list_head file_head;
 824         void *page;
 825         const char *full_path;
 826
 827         INIT_LIST_HEAD(&file_head);
 828         page = alloc_dentry_path();
 829         spin_lock(&tcon->open_file_lock);
 830         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 831                 full_path = build_path_from_dentry(cfile->dentry, page);
 832                 if (strstr(full_path, path)) {
 833                         if (delayed_work_pending(&cfile->deferred)) {
 834                                 if (cancel_delayed_work(&cfile->deferred)) {
 835                                         spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 836                                         cifs_del_deferred_close(cfile);
 837                                         spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 838
 839                                         tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 840                                         if (tmp_list == NULL)
 841                                                 break;
 842                                         tmp_list->cfile = cfile;
 843                                         list_add_tail(&tmp_list->list, &file_head);
 844                                 }
 845                         }
 846                 }
 847         }
 848         spin_unlock(&tcon->open_file_lock);
 849
 850         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 851                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 852                 list_del(&tmp_list->list);
 853                 kfree(tmp_list);
 854         }
 855         free_dentry_path(page);
 856 }
 857
 858 /* parses DFS referral V3 structure
 859  * caller is responsible for freeing target_nodes
 860  * returns:
 861  * - on success - 0
 862  * - on failure - errno
 863  */
 864 int
 865 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 866                     unsigned int *num_of_nodes,
 867                     struct dfs_info3_param **target_nodes,
 868                     const struct nls_table *nls_codepage, int remap,
 869                     const char *searchName, bool is_unicode)
 870 {
 871         int i, rc = 0;
 872         char *data_end;
 873         struct dfs_referral_level_3 *ref;
 874
 875         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 876
 877         if (*num_of_nodes < 1) {
 878                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 879                          *num_of_nodes);
 880                 rc = -EINVAL;
 881                 goto parse_DFS_referrals_exit;
 882         }
 883
 884         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 885         if (ref->VersionNumber != cpu_to_le16(3)) {
 886                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 887                          le16_to_cpu(ref->VersionNumber));
 888                 rc = -EINVAL;
 889                 goto parse_DFS_referrals_exit;
 890         }
 891
 892         /* get the upper boundary of the resp buffer */
 893         data_end = (char *)rsp + rsp_size;
 894
 895         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 896                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 897
 898         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 899                                 GFP_KERNEL);
 900         if (*target_nodes == NULL) {
 901                 rc = -ENOMEM;
 902                 goto parse_DFS_referrals_exit;
 903         }
 904
 905         /* collect necessary data from referrals */
 906         for (i = 0; i < *num_of_nodes; i++) {
 907                 char *temp;
 908                 int max_len;
 909                 struct dfs_info3_param *node = (*target_nodes)+i;
 910
 911                 node->flags = le32_to_cpu(rsp->DFSFlags);
 912                 if (is_unicode) {
 913                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 914                                                 GFP_KERNEL);
 915                         if (tmp == NULL) {
 916                                 rc = -ENOMEM;
 917                                 goto parse_DFS_referrals_exit;
 918                         }
 919                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 920                                            PATH_MAX, nls_codepage, remap);
 921                         node->path_consumed = cifs_utf16_bytes(tmp,
 922                                         le16_to_cpu(rsp->PathConsumed),
 923                                         nls_codepage);
 924                         kfree(tmp);
 925                 } else
 926                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 927
 928                 node->server_type = le16_to_cpu(ref->ServerType);
 929                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 930
 931                 /* copy DfsPath */
 932                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 933                 max_len = data_end - temp;
 934                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 935                                                 is_unicode, nls_codepage);
 936                 if (!node->path_name) {
 937                         rc = -ENOMEM;
 938                         goto parse_DFS_referrals_exit;
 939                 }
 940
 941                 /* copy link target UNC */
 942                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 943                 max_len = data_end - temp;
 944                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 945                                                 is_unicode, nls_codepage);
 946                 if (!node->node_name) {
 947                         rc = -ENOMEM;
 948                         goto parse_DFS_referrals_exit;
 949                 }
 950
 951                 node->ttl = le32_to_cpu(ref->TimeToLive);
 952
 953                 ref++;
 954         }
 955
 956 parse_DFS_referrals_exit:
 957         if (rc) {
 958                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 959                 *target_nodes = NULL;
 960                 *num_of_nodes = 0;
 961         }
 962         return rc;
 963 }
 964
 965 struct cifs_aio_ctx *
 966 cifs_aio_ctx_alloc(void)
 967 {
 968         struct cifs_aio_ctx *ctx;
 969
 970         /*
 971          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
 972          * to false so that we know when we have to unreference pages within
 973          * cifs_aio_ctx_release()
 974          */
 975         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
 976         if (!ctx)
 977                 return NULL;
 978
 979         INIT_LIST_HEAD(&ctx->list);
 980         mutex_init(&ctx->aio_mutex);
 981         init_completion(&ctx->done);
 982         kref_init(&ctx->refcount);
 983         return ctx;
 984 }
 985
 986 void
 987 cifs_aio_ctx_release(struct kref *refcount)
 988 {
 989         struct cifs_aio_ctx *ctx = container_of(refcount,
 990                                         struct cifs_aio_ctx, refcount);
 991
 992         cifsFileInfo_put(ctx->cfile);
 993
 994         /*
 995          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
 996          * which means that iov_iter_extract_pages() was a success and thus
 997          * that we may have references or pins on pages that we need to
 998          * release.
 999          */
1000         if (ctx->bv) {
1001                 if (ctx->should_dirty || ctx->bv_need_unpin) {
1002                         unsigned int i;
1003
1004                         for (i = 0; i < ctx->nr_pinned_pages; i++) {
1005                                 struct page *page = ctx->bv[i].bv_page;
1006
1007                                 if (ctx->should_dirty)
1008                                         set_page_dirty(page);
1009                                 if (ctx->bv_need_unpin)
1010                                         unpin_user_page(page);
1011                         }
1012                 }
1013                 kvfree(ctx->bv);
1014         }
1015
1016         kfree(ctx);
1017 }
1018
1019 /**
1020  * cifs_alloc_hash - allocate hash and hash context together
1021  * @name: The name of the crypto hash algo
1022  * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
1023  *
1024  * The caller has to make sure @sdesc is initialized to either NULL or
1025  * a valid context. It can be freed via cifs_free_hash().
1026  */
1027 int
1028 cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
1029 {
1030         int rc = 0;
1031         struct crypto_shash *alg = NULL;
1032
1033         if (*sdesc)
1034                 return 0;
1035
1036         alg = crypto_alloc_shash(name, 0, 0);
1037         if (IS_ERR(alg)) {
1038                 cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
1039                 rc = PTR_ERR(alg);
1040                 *sdesc = NULL;
1041                 return rc;
1042         }
1043
1044         *sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
1045         if (*sdesc == NULL) {
1046                 cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
1047                 crypto_free_shash(alg);
1048                 return -ENOMEM;
1049         }
1050
1051         (*sdesc)->tfm = alg;
1052         return 0;
1053 }
1054
1055 /**
1056  * cifs_free_hash - free hash and hash context together
1057  * @sdesc: Where to find the pointer to the hash TFM
1058  *
1059  * Freeing a NULL descriptor is safe.
1060  */
1061 void
1062 cifs_free_hash(struct shash_desc **sdesc)
1063 {
1064         if (unlikely(!sdesc) || !*sdesc)
1065                 return;
1066
1067         if ((*sdesc)->tfm) {
1068                 crypto_free_shash((*sdesc)->tfm);
1069                 (*sdesc)->tfm = NULL;
1070         }
1071
1072         kfree_sensitive(*sdesc);
1073         *sdesc = NULL;
1074 }
1075
1076 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1077 {
1078         const char *end;
1079
1080         /* skip initial slashes */
1081         while (*unc && (*unc == '\\' || *unc == '/'))
1082                 unc++;
1083
1084         end = unc;
1085
1086         while (*end && !(*end == '\\' || *end == '/'))
1087                 end++;
1088
1089         *h = unc;
1090         *len = end - unc;
1091 }
1092
1093 /**
1094  * copy_path_name - copy src path to dst, possibly truncating
1095  * @dst: The destination buffer
1096  * @src: The source name
1097  *
1098  * returns number of bytes written (including trailing nul)
1099  */
1100 int copy_path_name(char *dst, const char *src)
1101 {
1102         int name_len;
1103
1104         /*
1105          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1106          * will truncate and strlen(dst) will be PATH_MAX-1
1107          */
1108         name_len = strscpy(dst, src, PATH_MAX);
1109         if (WARN_ON_ONCE(name_len < 0))
1110                 name_len = PATH_MAX-1;
1111
1112         /* we count the trailing nul */
1113         name_len++;
1114         return name_len;
1115 }
1116
1117 struct super_cb_data {
1118         void *data;
1119         struct super_block *sb;
1120 };
1121
1122 static void tcon_super_cb(struct super_block *sb, void *arg)
1123 {
1124         struct super_cb_data *sd = arg;
1125         struct cifs_sb_info *cifs_sb;
1126         struct cifs_tcon *t1 = sd->data, *t2;
1127
1128         if (sd->sb)
1129                 return;
1130
1131         cifs_sb = CIFS_SB(sb);
1132         t2 = cifs_sb_master_tcon(cifs_sb);
1133
1134         spin_lock(&t2->tc_lock);
1135         if (t1->ses == t2->ses &&
1136             t1->ses->server == t2->ses->server &&
1137             t2->origin_fullpath &&
1138             dfs_src_pathname_equal(t2->origin_fullpath, t1->origin_fullpath))
1139                 sd->sb = sb;
1140         spin_unlock(&t2->tc_lock);
1141 }
1142
1143 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1144                                             void *data)
1145 {
1146         struct super_cb_data sd = {
1147                 .data = data,
1148                 .sb = NULL,
1149         };
1150         struct file_system_type **fs_type = (struct file_system_type *[]) {
1151                 &cifs_fs_type, &smb3_fs_type, NULL,
1152         };
1153
1154         for (; *fs_type; fs_type++) {
1155                 iterate_supers_type(*fs_type, f, &sd);
1156                 if (sd.sb) {
1157                         /*
1158                          * Grab an active reference in order to prevent automounts (DFS links)
1159                          * of expiring and then freeing up our cifs superblock pointer while
1160                          * we're doing failover.
1161                          */
1162                         cifs_sb_active(sd.sb);
1163                         return sd.sb;
1164                 }
1165         }
1166         pr_warn_once("%s: could not find dfs superblock\n", __func__);
1167         return ERR_PTR(-EINVAL);
1168 }
1169
1170 static void __cifs_put_super(struct super_block *sb)
1171 {
1172         if (!IS_ERR_OR_NULL(sb))
1173                 cifs_sb_deactive(sb);
1174 }
1175
1176 struct super_block *cifs_get_dfs_tcon_super(struct cifs_tcon *tcon)
1177 {
1178         spin_lock(&tcon->tc_lock);
1179         if (!tcon->origin_fullpath) {
1180                 spin_unlock(&tcon->tc_lock);
1181                 return ERR_PTR(-ENOENT);
1182         }
1183         spin_unlock(&tcon->tc_lock);
1184         return __cifs_get_super(tcon_super_cb, tcon);
1185 }
1186
1187 void cifs_put_tcp_super(struct super_block *sb)
1188 {
1189         __cifs_put_super(sb);
1190 }
1191
1192 #ifdef CONFIG_CIFS_DFS_UPCALL
1193 int match_target_ip(struct TCP_Server_Info *server,
1194                     const char *share, size_t share_len,
1195                     bool *result)
1196 {
1197         int rc;
1198         char *target;
1199         struct sockaddr_storage ss;
1200
1201         *result = false;
1202
1203         target = kzalloc(share_len + 3, GFP_KERNEL);
1204         if (!target)
1205                 return -ENOMEM;
1206
1207         scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1208
1209         cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1210
1211         rc = dns_resolve_server_name_to_ip(target, (struct sockaddr *)&ss, NULL);
1212         kfree(target);
1213
1214         if (rc < 0)
1215                 return rc;
1216
1217         spin_lock(&server->srv_lock);
1218         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
1219         spin_unlock(&server->srv_lock);
1220         cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1221         return 0;
1222 }
1223
1224 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1225 {
1226         int rc;
1227
1228         kfree(cifs_sb->prepath);
1229         cifs_sb->prepath = NULL;
1230
1231         if (prefix && *prefix) {
1232                 cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
1233                 if (IS_ERR(cifs_sb->prepath)) {
1234                         rc = PTR_ERR(cifs_sb->prepath);
1235                         cifs_sb->prepath = NULL;
1236                         return rc;
1237                 }
1238                 if (cifs_sb->prepath)
1239                         convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1240         }
1241
1242         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1243         return 0;
1244 }
1245
1246 /*
1247  * Handle weird Windows SMB server behaviour. It responds with
1248  * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
1249  * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
1250  * non-ASCII unicode symbols.
1251  */
1252 int cifs_inval_name_dfs_link_error(const unsigned int xid,
1253                                    struct cifs_tcon *tcon,
1254                                    struct cifs_sb_info *cifs_sb,
1255                                    const char *full_path,
1256                                    bool *islink)
1257 {
1258         struct cifs_ses *ses = tcon->ses;
1259         size_t len;
1260         char *path;
1261         char *ref_path;
1262
1263         *islink = false;
1264
1265         /*
1266          * Fast path - skip check when @full_path doesn't have a prefix path to
1267          * look up or tcon is not DFS.
1268          */
1269         if (strlen(full_path) < 2 || !cifs_sb ||
1270             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
1271             !is_tcon_dfs(tcon))
1272                 return 0;
1273
1274         spin_lock(&tcon->tc_lock);
1275         if (!tcon->origin_fullpath) {
1276                 spin_unlock(&tcon->tc_lock);
1277                 return 0;
1278         }
1279         spin_unlock(&tcon->tc_lock);
1280
1281         /*
1282          * Slow path - tcon is DFS and @full_path has prefix path, so attempt
1283          * to get a referral to figure out whether it is an DFS link.
1284          */
1285         len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
1286         path = kmalloc(len, GFP_KERNEL);
1287         if (!path)
1288                 return -ENOMEM;
1289
1290         scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
1291         ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
1292                                             cifs_remap(cifs_sb));
1293         kfree(path);
1294
1295         if (IS_ERR(ref_path)) {
1296                 if (PTR_ERR(ref_path) != -EINVAL)
1297                         return PTR_ERR(ref_path);
1298         } else {
1299                 struct dfs_info3_param *refs = NULL;
1300                 int num_refs = 0;
1301
1302                 /*
1303                  * XXX: we are not using dfs_cache_find() here because we might
1304                  * end up filling all the DFS cache and thus potentially
1305                  * removing cached DFS targets that the client would eventually
1306                  * need during failover.
1307                  */
1308                 ses = CIFS_DFS_ROOT_SES(ses);
1309                 if (ses->server->ops->get_dfs_refer &&
1310                     !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
1311                                                      &num_refs, cifs_sb->local_nls,
1312                                                      cifs_remap(cifs_sb)))
1313                         *islink = refs[0].server_type == DFS_TYPE_LINK;
1314                 free_dfs_info_array(refs, num_refs);
1315                 kfree(ref_path);
1316         }
1317         return 0;
1318 }
1319 #endif
1320
1321 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
1322 {
1323         int timeout = 10;
1324         int rc;
1325
1326         spin_lock(&server->srv_lock);
1327         if (server->tcpStatus != CifsNeedReconnect) {
1328                 spin_unlock(&server->srv_lock);
1329                 return 0;
1330         }
1331         timeout *= server->nr_targets;
1332         spin_unlock(&server->srv_lock);
1333
1334         /*
1335          * Give demultiplex thread up to 10 seconds to each target available for
1336          * reconnect -- should be greater than cifs socket timeout which is 7
1337          * seconds.
1338          *
1339          * On "soft" mounts we wait once. Hard mounts keep retrying until
1340          * process is killed or server comes back on-line.
1341          */
1342         do {
1343                 rc = wait_event_interruptible_timeout(server->response_q,
1344                                                       (server->tcpStatus != CifsNeedReconnect),
1345                                                       timeout * HZ);
1346                 if (rc < 0) {
1347                         cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
1348                                  __func__);
1349                         return -ERESTARTSYS;
1350                 }
1351
1352                 /* are we still trying to reconnect? */
1353                 spin_lock(&server->srv_lock);
1354                 if (server->tcpStatus != CifsNeedReconnect) {
1355                         spin_unlock(&server->srv_lock);
1356                         return 0;
1357                 }
1358                 spin_unlock(&server->srv_lock);
1359         } while (retry);
1360
1361         cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
1362         return -EHOSTDOWN;
1363 }