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 #endif
  26 #include "fs_context.h"
  27 #include "cached_dir.h"
  28
  29 extern mempool_t *cifs_sm_req_poolp;
  30 extern mempool_t *cifs_req_poolp;
  31
  32 /* The xid serves as a useful identifier for each incoming vfs request,
  33    in a similar way to the mid which is useful to track each sent smb,
  34    and CurrentXid can also provide a running counter (although it
  35    will eventually wrap past zero) of the total vfs operations handled
  36    since the cifs fs was mounted */
  37
  38 unsigned int
  39 _get_xid(void)
  40 {
  41         unsigned int xid;
  42
  43         spin_lock(&GlobalMid_Lock);
  44         GlobalTotalActiveXid++;
  45
  46         /* keep high water mark for number of simultaneous ops in filesystem */
  47         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  48                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  49         if (GlobalTotalActiveXid > 65000)
  50                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  51         xid = GlobalCurrentXid++;
  52         spin_unlock(&GlobalMid_Lock);
  53         return xid;
  54 }
  55
  56 void
  57 _free_xid(unsigned int xid)
  58 {
  59         spin_lock(&GlobalMid_Lock);
  60         /* if (GlobalTotalActiveXid == 0)
  61                 BUG(); */
  62         GlobalTotalActiveXid--;
  63         spin_unlock(&GlobalMid_Lock);
  64 }
  65
  66 struct cifs_ses *
  67 sesInfoAlloc(void)
  68 {
  69         struct cifs_ses *ret_buf;
  70
  71         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  72         if (ret_buf) {
  73                 atomic_inc(&sesInfoAllocCount);
  74                 spin_lock_init(&ret_buf->ses_lock);
  75                 ret_buf->ses_status = SES_NEW;
  76                 ++ret_buf->ses_count;
  77                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  78                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  79                 mutex_init(&ret_buf->session_mutex);
  80                 spin_lock_init(&ret_buf->iface_lock);
  81                 INIT_LIST_HEAD(&ret_buf->iface_list);
  82                 spin_lock_init(&ret_buf->chan_lock);
  83         }
  84         return ret_buf;
  85 }
  86
  87 void
  88 sesInfoFree(struct cifs_ses *buf_to_free)
  89 {
  90         struct cifs_server_iface *iface = NULL, *niface = NULL;
  91
  92         if (buf_to_free == NULL) {
  93                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  94                 return;
  95         }
  96
  97         atomic_dec(&sesInfoAllocCount);
  98         kfree(buf_to_free->serverOS);
  99         kfree(buf_to_free->serverDomain);
 100         kfree(buf_to_free->serverNOS);
 101         kfree_sensitive(buf_to_free->password);
 102         kfree(buf_to_free->user_name);
 103         kfree(buf_to_free->domainName);
 104         kfree_sensitive(buf_to_free->auth_key.response);
 105         spin_lock(&buf_to_free->iface_lock);
 106         list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
 107                                  iface_head)
 108                 kref_put(&iface->refcount, release_iface);
 109         spin_unlock(&buf_to_free->iface_lock);
 110         kfree_sensitive(buf_to_free);
 111 }
 112
 113 struct cifs_tcon *
 114 tconInfoAlloc(void)
 115 {
 116         struct cifs_tcon *ret_buf;
 117
 118         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 119         if (!ret_buf)
 120                 return NULL;
 121         ret_buf->cfids = init_cached_dirs();
 122         if (!ret_buf->cfids) {
 123                 kfree(ret_buf);
 124                 return NULL;
 125         }
 126
 127         atomic_inc(&tconInfoAllocCount);
 128         ret_buf->status = TID_NEW;
 129         ++ret_buf->tc_count;
 130         spin_lock_init(&ret_buf->tc_lock);
 131         INIT_LIST_HEAD(&ret_buf->openFileList);
 132         INIT_LIST_HEAD(&ret_buf->tcon_list);
 133         spin_lock_init(&ret_buf->open_file_lock);
 134         spin_lock_init(&ret_buf->stat_lock);
 135         atomic_set(&ret_buf->num_local_opens, 0);
 136         atomic_set(&ret_buf->num_remote_opens, 0);
 137
 138         return ret_buf;
 139 }
 140
 141 void
 142 tconInfoFree(struct cifs_tcon *tcon)
 143 {
 144         if (tcon == NULL) {
 145                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 146                 return;
 147         }
 148         free_cached_dirs(tcon->cfids);
 149         atomic_dec(&tconInfoAllocCount);
 150         kfree(tcon->nativeFileSystem);
 151         kfree_sensitive(tcon->password);
 152         kfree(tcon);
 153 }
 154
 155 struct smb_hdr *
 156 cifs_buf_get(void)
 157 {
 158         struct smb_hdr *ret_buf = NULL;
 159         /*
 160          * SMB2 header is bigger than CIFS one - no problems to clean some
 161          * more bytes for CIFS.
 162          */
 163         size_t buf_size = sizeof(struct smb2_hdr);
 164
 165         /*
 166          * We could use negotiated size instead of max_msgsize -
 167          * but it may be more efficient to always alloc same size
 168          * albeit slightly larger than necessary and maxbuffersize
 169          * defaults to this and can not be bigger.
 170          */
 171         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 172
 173         /* clear the first few header bytes */
 174         /* for most paths, more is cleared in header_assemble */
 175         memset(ret_buf, 0, buf_size + 3);
 176         atomic_inc(&buf_alloc_count);
 177 #ifdef CONFIG_CIFS_STATS2
 178         atomic_inc(&total_buf_alloc_count);
 179 #endif /* CONFIG_CIFS_STATS2 */
 180
 181         return ret_buf;
 182 }
 183
 184 void
 185 cifs_buf_release(void *buf_to_free)
 186 {
 187         if (buf_to_free == NULL) {
 188                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 189                 return;
 190         }
 191         mempool_free(buf_to_free, cifs_req_poolp);
 192
 193         atomic_dec(&buf_alloc_count);
 194         return;
 195 }
 196
 197 struct smb_hdr *
 198 cifs_small_buf_get(void)
 199 {
 200         struct smb_hdr *ret_buf = NULL;
 201
 202 /* We could use negotiated size instead of max_msgsize -
 203    but it may be more efficient to always alloc same size
 204    albeit slightly larger than necessary and maxbuffersize
 205    defaults to this and can not be bigger */
 206         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 207         /* No need to clear memory here, cleared in header assemble */
 208         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 209         atomic_inc(&small_buf_alloc_count);
 210 #ifdef CONFIG_CIFS_STATS2
 211         atomic_inc(&total_small_buf_alloc_count);
 212 #endif /* CONFIG_CIFS_STATS2 */
 213
 214         return ret_buf;
 215 }
 216
 217 void
 218 cifs_small_buf_release(void *buf_to_free)
 219 {
 220
 221         if (buf_to_free == NULL) {
 222                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 223                 return;
 224         }
 225         mempool_free(buf_to_free, cifs_sm_req_poolp);
 226
 227         atomic_dec(&small_buf_alloc_count);
 228         return;
 229 }
 230
 231 void
 232 free_rsp_buf(int resp_buftype, void *rsp)
 233 {
 234         if (resp_buftype == CIFS_SMALL_BUFFER)
 235                 cifs_small_buf_release(rsp);
 236         else if (resp_buftype == CIFS_LARGE_BUFFER)
 237                 cifs_buf_release(rsp);
 238 }
 239
 240 /* NB: MID can not be set if treeCon not passed in, in that
 241    case it is responsbility of caller to set the mid */
 242 void
 243 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 244                 const struct cifs_tcon *treeCon, int word_count
 245                 /* length of fixed section (word count) in two byte units  */)
 246 {
 247         char *temp = (char *) buffer;
 248
 249         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 250
 251         buffer->smb_buf_length = cpu_to_be32(
 252             (2 * word_count) + sizeof(struct smb_hdr) -
 253             4 /*  RFC 1001 length field does not count */  +
 254             2 /* for bcc field itself */) ;
 255
 256         buffer->Protocol[0] = 0xFF;
 257         buffer->Protocol[1] = 'S';
 258         buffer->Protocol[2] = 'M';
 259         buffer->Protocol[3] = 'B';
 260         buffer->Command = smb_command;
 261         buffer->Flags = 0x00;   /* case sensitive */
 262         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 263         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 264         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 265         if (treeCon) {
 266                 buffer->Tid = treeCon->tid;
 267                 if (treeCon->ses) {
 268                         if (treeCon->ses->capabilities & CAP_UNICODE)
 269                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 270                         if (treeCon->ses->capabilities & CAP_STATUS32)
 271                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 272
 273                         /* Uid is not converted */
 274                         buffer->Uid = treeCon->ses->Suid;
 275                         if (treeCon->ses->server)
 276                                 buffer->Mid = get_next_mid(treeCon->ses->server);
 277                 }
 278                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 279                         buffer->Flags2 |= SMBFLG2_DFS;
 280                 if (treeCon->nocase)
 281                         buffer->Flags  |= SMBFLG_CASELESS;
 282                 if ((treeCon->ses) && (treeCon->ses->server))
 283                         if (treeCon->ses->server->sign)
 284                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 285         }
 286
 287 /*  endian conversion of flags is now done just before sending */
 288         buffer->WordCount = (char) word_count;
 289         return;
 290 }
 291
 292 static int
 293 check_smb_hdr(struct smb_hdr *smb)
 294 {
 295         /* does it have the right SMB "signature" ? */
 296         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 297                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 298                          *(unsigned int *)smb->Protocol);
 299                 return 1;
 300         }
 301
 302         /* if it's a response then accept */
 303         if (smb->Flags & SMBFLG_RESPONSE)
 304                 return 0;
 305
 306         /* only one valid case where server sends us request */
 307         if (smb->Command == SMB_COM_LOCKING_ANDX)
 308                 return 0;
 309
 310         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 311                  get_mid(smb));
 312         return 1;
 313 }
 314
 315 int
 316 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 317 {
 318         struct smb_hdr *smb = (struct smb_hdr *)buf;
 319         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 320         __u32 clc_len;  /* calculated length */
 321         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 322                  total_read, rfclen);
 323
 324         /* is this frame too small to even get to a BCC? */
 325         if (total_read < 2 + sizeof(struct smb_hdr)) {
 326                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 327                             && (smb->Status.CifsError != 0)) {
 328                         /* it's an error return */
 329                         smb->WordCount = 0;
 330                         /* some error cases do not return wct and bcc */
 331                         return 0;
 332                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 333                                 (smb->WordCount == 0)) {
 334                         char *tmp = (char *)smb;
 335                         /* Need to work around a bug in two servers here */
 336                         /* First, check if the part of bcc they sent was zero */
 337                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 338                                 /* some servers return only half of bcc
 339                                  * on simple responses (wct, bcc both zero)
 340                                  * in particular have seen this on
 341                                  * ulogoffX and FindClose. This leaves
 342                                  * one byte of bcc potentially unitialized
 343                                  */
 344                                 /* zero rest of bcc */
 345                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 346                                 return 0;
 347                         }
 348                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 349                 } else {
 350                         cifs_dbg(VFS, "Length less than smb header size\n");
 351                 }
 352                 return -EIO;
 353         } else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
 354                 cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
 355                          __func__, smb->WordCount);
 356                 return -EIO;
 357         }
 358
 359         /* otherwise, there is enough to get to the BCC */
 360         if (check_smb_hdr(smb))
 361                 return -EIO;
 362         clc_len = smbCalcSize(smb);
 363
 364         if (4 + rfclen != total_read) {
 365                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 366                          rfclen);
 367                 return -EIO;
 368         }
 369
 370         if (4 + rfclen != clc_len) {
 371                 __u16 mid = get_mid(smb);
 372                 /* check if bcc wrapped around for large read responses */
 373                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 374                         /* check if lengths match mod 64K */
 375                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 376                                 return 0; /* bcc wrapped */
 377                 }
 378                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 379                          clc_len, 4 + rfclen, mid);
 380
 381                 if (4 + rfclen < clc_len) {
 382                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 383                                  rfclen, mid);
 384                         return -EIO;
 385                 } else if (rfclen > clc_len + 512) {
 386                         /*
 387                          * Some servers (Windows XP in particular) send more
 388                          * data than the lengths in the SMB packet would
 389                          * indicate on certain calls (byte range locks and
 390                          * trans2 find first calls in particular). While the
 391                          * client can handle such a frame by ignoring the
 392                          * trailing data, we choose limit the amount of extra
 393                          * data to 512 bytes.
 394                          */
 395                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 396                                  rfclen, mid);
 397                         return -EIO;
 398                 }
 399         }
 400         return 0;
 401 }
 402
 403 bool
 404 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 405 {
 406         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 407         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 408         struct TCP_Server_Info *pserver;
 409         struct cifs_ses *ses;
 410         struct cifs_tcon *tcon;
 411         struct cifsInodeInfo *pCifsInode;
 412         struct cifsFileInfo *netfile;
 413
 414         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 415         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 416            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 417                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 418                         (struct smb_com_transaction_change_notify_rsp *)buf;
 419                 struct file_notify_information *pnotify;
 420                 __u32 data_offset = 0;
 421                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 422
 423                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 424                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 425
 426                         if (data_offset >
 427                             len - sizeof(struct file_notify_information)) {
 428                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
 429                                          data_offset);
 430                                 return true;
 431                         }
 432                         pnotify = (struct file_notify_information *)
 433                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 434                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 435                                  pnotify->FileName, pnotify->Action);
 436                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 437                                 sizeof(struct smb_hdr)+60); */
 438                         return true;
 439                 }
 440                 if (pSMBr->hdr.Status.CifsError) {
 441                         cifs_dbg(FYI, "notify err 0x%x\n",
 442                                  pSMBr->hdr.Status.CifsError);
 443                         return true;
 444                 }
 445                 return false;
 446         }
 447         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 448                 return false;
 449         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 450                 /* no sense logging error on invalid handle on oplock
 451                    break - harmless race between close request and oplock
 452                    break response is expected from time to time writing out
 453                    large dirty files cached on the client */
 454                 if ((NT_STATUS_INVALID_HANDLE) ==
 455                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 456                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
 457                         return true;
 458                 } else if (ERRbadfid ==
 459                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 460                         return true;
 461                 } else {
 462                         return false; /* on valid oplock brk we get "request" */
 463                 }
 464         }
 465         if (pSMB->hdr.WordCount != 8)
 466                 return false;
 467
 468         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 469                  pSMB->LockType, pSMB->OplockLevel);
 470         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 471                 return false;
 472
 473         /* If server is a channel, select the primary channel */
 474         pserver = CIFS_SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
 475
 476         /* look up tcon based on tid & uid */
 477         spin_lock(&cifs_tcp_ses_lock);
 478         list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 479                 if (cifs_ses_exiting(ses))
 480                         continue;
 481                 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 482                         if (tcon->tid != buf->Tid)
 483                                 continue;
 484
 485                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 486                         spin_lock(&tcon->open_file_lock);
 487                         list_for_each_entry(netfile, &tcon->openFileList, tlist) {
 488                                 if (pSMB->Fid != netfile->fid.netfid)
 489                                         continue;
 490
 491                                 cifs_dbg(FYI, "file id match, oplock break\n");
 492                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 493
 494                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 495                                         &pCifsInode->flags);
 496
 497                                 netfile->oplock_epoch = 0;
 498                                 netfile->oplock_level = pSMB->OplockLevel;
 499                                 netfile->oplock_break_cancelled = false;
 500                                 cifs_queue_oplock_break(netfile);
 501
 502                                 spin_unlock(&tcon->open_file_lock);
 503                                 spin_unlock(&cifs_tcp_ses_lock);
 504                                 return true;
 505                         }
 506                         spin_unlock(&tcon->open_file_lock);
 507                         spin_unlock(&cifs_tcp_ses_lock);
 508                         cifs_dbg(FYI, "No matching file for oplock break\n");
 509                         return true;
 510                 }
 511         }
 512         spin_unlock(&cifs_tcp_ses_lock);
 513         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 514         return true;
 515 }
 516
 517 void
 518 dump_smb(void *buf, int smb_buf_length)
 519 {
 520         if (traceSMB == 0)
 521                 return;
 522
 523         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 524                        smb_buf_length, true);
 525 }
 526
 527 void
 528 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 529 {
 530         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 531                 struct cifs_tcon *tcon = NULL;
 532
 533                 if (cifs_sb->master_tlink)
 534                         tcon = cifs_sb_master_tcon(cifs_sb);
 535
 536                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 537                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
 538                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 539                          tcon ? tcon->tree_name : "new server");
 540                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 541                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 542
 543         }
 544 }
 545
 546 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 547 {
 548         oplock &= 0xF;
 549
 550         if (oplock == OPLOCK_EXCLUSIVE) {
 551                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 552                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 553                          &cinode->netfs.inode);
 554         } else if (oplock == OPLOCK_READ) {
 555                 cinode->oplock = CIFS_CACHE_READ_FLG;
 556                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 557                          &cinode->netfs.inode);
 558         } else
 559                 cinode->oplock = 0;
 560 }
 561
 562 /*
 563  * We wait for oplock breaks to be processed before we attempt to perform
 564  * writes.
 565  */
 566 int cifs_get_writer(struct cifsInodeInfo *cinode)
 567 {
 568         int rc;
 569
 570 start:
 571         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 572                          TASK_KILLABLE);
 573         if (rc)
 574                 return rc;
 575
 576         spin_lock(&cinode->writers_lock);
 577         if (!cinode->writers)
 578                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 579         cinode->writers++;
 580         /* Check to see if we have started servicing an oplock break */
 581         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 582                 cinode->writers--;
 583                 if (cinode->writers == 0) {
 584                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 585                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 586                 }
 587                 spin_unlock(&cinode->writers_lock);
 588                 goto start;
 589         }
 590         spin_unlock(&cinode->writers_lock);
 591         return 0;
 592 }
 593
 594 void cifs_put_writer(struct cifsInodeInfo *cinode)
 595 {
 596         spin_lock(&cinode->writers_lock);
 597         cinode->writers--;
 598         if (cinode->writers == 0) {
 599                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 600                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 601         }
 602         spin_unlock(&cinode->writers_lock);
 603 }
 604
 605 /**
 606  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 607  * @cfile: The file to break the oplock on
 608  *
 609  * This function is called from the demultiplex thread when it
 610  * receives an oplock break for @cfile.
 611  *
 612  * Assumes the tcon->open_file_lock is held.
 613  * Assumes cfile->file_info_lock is NOT held.
 614  */
 615 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 616 {
 617         /*
 618          * Bump the handle refcount now while we hold the
 619          * open_file_lock to enforce the validity of it for the oplock
 620          * break handler. The matching put is done at the end of the
 621          * handler.
 622          */
 623         cifsFileInfo_get(cfile);
 624
 625         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 626 }
 627
 628 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 629 {
 630         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 631         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 632 }
 633
 634 bool
 635 backup_cred(struct cifs_sb_info *cifs_sb)
 636 {
 637         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 638                 if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
 639                         return true;
 640         }
 641         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 642                 if (in_group_p(cifs_sb->ctx->backupgid))
 643                         return true;
 644         }
 645
 646         return false;
 647 }
 648
 649 void
 650 cifs_del_pending_open(struct cifs_pending_open *open)
 651 {
 652         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 653         list_del(&open->olist);
 654         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 655 }
 656
 657 void
 658 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 659                              struct cifs_pending_open *open)
 660 {
 661         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 662         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 663         open->tlink = tlink;
 664         fid->pending_open = open;
 665         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 666 }
 667
 668 void
 669 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 670                       struct cifs_pending_open *open)
 671 {
 672         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 673         cifs_add_pending_open_locked(fid, tlink, open);
 674         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 675 }
 676
 677 /*
 678  * Critical section which runs after acquiring deferred_lock.
 679  * As there is no reference count on cifs_deferred_close, pdclose
 680  * should not be used outside deferred_lock.
 681  */
 682 bool
 683 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
 684 {
 685         struct cifs_deferred_close *dclose;
 686
 687         list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
 688                 if ((dclose->netfid == cfile->fid.netfid) &&
 689                         (dclose->persistent_fid == cfile->fid.persistent_fid) &&
 690                         (dclose->volatile_fid == cfile->fid.volatile_fid)) {
 691                         *pdclose = dclose;
 692                         return true;
 693                 }
 694         }
 695         return false;
 696 }
 697
 698 /*
 699  * Critical section which runs after acquiring deferred_lock.
 700  */
 701 void
 702 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
 703 {
 704         bool is_deferred = false;
 705         struct cifs_deferred_close *pdclose;
 706
 707         is_deferred = cifs_is_deferred_close(cfile, &pdclose);
 708         if (is_deferred) {
 709                 kfree(dclose);
 710                 return;
 711         }
 712
 713         dclose->tlink = cfile->tlink;
 714         dclose->netfid = cfile->fid.netfid;
 715         dclose->persistent_fid = cfile->fid.persistent_fid;
 716         dclose->volatile_fid = cfile->fid.volatile_fid;
 717         list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
 718 }
 719
 720 /*
 721  * Critical section which runs after acquiring deferred_lock.
 722  */
 723 void
 724 cifs_del_deferred_close(struct cifsFileInfo *cfile)
 725 {
 726         bool is_deferred = false;
 727         struct cifs_deferred_close *dclose;
 728
 729         is_deferred = cifs_is_deferred_close(cfile, &dclose);
 730         if (!is_deferred)
 731                 return;
 732         list_del(&dclose->dlist);
 733         kfree(dclose);
 734 }
 735
 736 void
 737 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
 738 {
 739         struct cifsFileInfo *cfile = NULL;
 740         struct file_list *tmp_list, *tmp_next_list;
 741         struct list_head file_head;
 742
 743         if (cifs_inode == NULL)
 744                 return;
 745
 746         INIT_LIST_HEAD(&file_head);
 747         spin_lock(&cifs_inode->open_file_lock);
 748         list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
 749                 if (delayed_work_pending(&cfile->deferred)) {
 750                         if (cancel_delayed_work(&cfile->deferred)) {
 751                                 spin_lock(&cifs_inode->deferred_lock);
 752                                 cifs_del_deferred_close(cfile);
 753                                 spin_unlock(&cifs_inode->deferred_lock);
 754
 755                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 756                                 if (tmp_list == NULL)
 757                                         break;
 758                                 tmp_list->cfile = cfile;
 759                                 list_add_tail(&tmp_list->list, &file_head);
 760                         }
 761                 }
 762         }
 763         spin_unlock(&cifs_inode->open_file_lock);
 764
 765         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 766                 _cifsFileInfo_put(tmp_list->cfile, false, false);
 767                 list_del(&tmp_list->list);
 768                 kfree(tmp_list);
 769         }
 770 }
 771
 772 void
 773 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
 774 {
 775         struct cifsFileInfo *cfile;
 776         struct file_list *tmp_list, *tmp_next_list;
 777         struct list_head file_head;
 778
 779         INIT_LIST_HEAD(&file_head);
 780         spin_lock(&tcon->open_file_lock);
 781         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 782                 if (delayed_work_pending(&cfile->deferred)) {
 783                         if (cancel_delayed_work(&cfile->deferred)) {
 784                                 spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 785                                 cifs_del_deferred_close(cfile);
 786                                 spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 787
 788                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 789                                 if (tmp_list == NULL)
 790                                         break;
 791                                 tmp_list->cfile = cfile;
 792                                 list_add_tail(&tmp_list->list, &file_head);
 793                         }
 794                 }
 795         }
 796         spin_unlock(&tcon->open_file_lock);
 797
 798         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 799                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 800                 list_del(&tmp_list->list);
 801                 kfree(tmp_list);
 802         }
 803 }
 804 void
 805 cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
 806 {
 807         struct cifsFileInfo *cfile;
 808         struct file_list *tmp_list, *tmp_next_list;
 809         struct list_head file_head;
 810         void *page;
 811         const char *full_path;
 812
 813         INIT_LIST_HEAD(&file_head);
 814         page = alloc_dentry_path();
 815         spin_lock(&tcon->open_file_lock);
 816         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 817                 full_path = build_path_from_dentry(cfile->dentry, page);
 818                 if (strstr(full_path, path)) {
 819                         if (delayed_work_pending(&cfile->deferred)) {
 820                                 if (cancel_delayed_work(&cfile->deferred)) {
 821                                         spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 822                                         cifs_del_deferred_close(cfile);
 823                                         spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 824
 825                                         tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 826                                         if (tmp_list == NULL)
 827                                                 break;
 828                                         tmp_list->cfile = cfile;
 829                                         list_add_tail(&tmp_list->list, &file_head);
 830                                 }
 831                         }
 832                 }
 833         }
 834         spin_unlock(&tcon->open_file_lock);
 835
 836         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 837                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 838                 list_del(&tmp_list->list);
 839                 kfree(tmp_list);
 840         }
 841         free_dentry_path(page);
 842 }
 843
 844 /* parses DFS referral V3 structure
 845  * caller is responsible for freeing target_nodes
 846  * returns:
 847  * - on success - 0
 848  * - on failure - errno
 849  */
 850 int
 851 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 852                     unsigned int *num_of_nodes,
 853                     struct dfs_info3_param **target_nodes,
 854                     const struct nls_table *nls_codepage, int remap,
 855                     const char *searchName, bool is_unicode)
 856 {
 857         int i, rc = 0;
 858         char *data_end;
 859         struct dfs_referral_level_3 *ref;
 860
 861         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 862
 863         if (*num_of_nodes < 1) {
 864                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 865                          *num_of_nodes);
 866                 rc = -EINVAL;
 867                 goto parse_DFS_referrals_exit;
 868         }
 869
 870         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 871         if (ref->VersionNumber != cpu_to_le16(3)) {
 872                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 873                          le16_to_cpu(ref->VersionNumber));
 874                 rc = -EINVAL;
 875                 goto parse_DFS_referrals_exit;
 876         }
 877
 878         /* get the upper boundary of the resp buffer */
 879         data_end = (char *)rsp + rsp_size;
 880
 881         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 882                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 883
 884         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 885                                 GFP_KERNEL);
 886         if (*target_nodes == NULL) {
 887                 rc = -ENOMEM;
 888                 goto parse_DFS_referrals_exit;
 889         }
 890
 891         /* collect necessary data from referrals */
 892         for (i = 0; i < *num_of_nodes; i++) {
 893                 char *temp;
 894                 int max_len;
 895                 struct dfs_info3_param *node = (*target_nodes)+i;
 896
 897                 node->flags = le32_to_cpu(rsp->DFSFlags);
 898                 if (is_unicode) {
 899                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 900                                                 GFP_KERNEL);
 901                         if (tmp == NULL) {
 902                                 rc = -ENOMEM;
 903                                 goto parse_DFS_referrals_exit;
 904                         }
 905                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 906                                            PATH_MAX, nls_codepage, remap);
 907                         node->path_consumed = cifs_utf16_bytes(tmp,
 908                                         le16_to_cpu(rsp->PathConsumed),
 909                                         nls_codepage);
 910                         kfree(tmp);
 911                 } else
 912                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 913
 914                 node->server_type = le16_to_cpu(ref->ServerType);
 915                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 916
 917                 /* copy DfsPath */
 918                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 919                 max_len = data_end - temp;
 920                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 921                                                 is_unicode, nls_codepage);
 922                 if (!node->path_name) {
 923                         rc = -ENOMEM;
 924                         goto parse_DFS_referrals_exit;
 925                 }
 926
 927                 /* copy link target UNC */
 928                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 929                 max_len = data_end - temp;
 930                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 931                                                 is_unicode, nls_codepage);
 932                 if (!node->node_name) {
 933                         rc = -ENOMEM;
 934                         goto parse_DFS_referrals_exit;
 935                 }
 936
 937                 node->ttl = le32_to_cpu(ref->TimeToLive);
 938
 939                 ref++;
 940         }
 941
 942 parse_DFS_referrals_exit:
 943         if (rc) {
 944                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 945                 *target_nodes = NULL;
 946                 *num_of_nodes = 0;
 947         }
 948         return rc;
 949 }
 950
 951 struct cifs_aio_ctx *
 952 cifs_aio_ctx_alloc(void)
 953 {
 954         struct cifs_aio_ctx *ctx;
 955
 956         /*
 957          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
 958          * to false so that we know when we have to unreference pages within
 959          * cifs_aio_ctx_release()
 960          */
 961         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
 962         if (!ctx)
 963                 return NULL;
 964
 965         INIT_LIST_HEAD(&ctx->list);
 966         mutex_init(&ctx->aio_mutex);
 967         init_completion(&ctx->done);
 968         kref_init(&ctx->refcount);
 969         return ctx;
 970 }
 971
 972 void
 973 cifs_aio_ctx_release(struct kref *refcount)
 974 {
 975         struct cifs_aio_ctx *ctx = container_of(refcount,
 976                                         struct cifs_aio_ctx, refcount);
 977
 978         cifsFileInfo_put(ctx->cfile);
 979
 980         /*
 981          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
 982          * which means that iov_iter_get_pages() was a success and thus that
 983          * we have taken reference on pages.
 984          */
 985         if (ctx->bv) {
 986                 unsigned i;
 987
 988                 for (i = 0; i < ctx->npages; i++) {
 989                         if (ctx->should_dirty)
 990                                 set_page_dirty(ctx->bv[i].bv_page);
 991                         put_page(ctx->bv[i].bv_page);
 992                 }
 993                 kvfree(ctx->bv);
 994         }
 995
 996         kfree(ctx);
 997 }
 998
 999 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
1000
1001 int
1002 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
1003 {
1004         ssize_t rc;
1005         unsigned int cur_npages;
1006         unsigned int npages = 0;
1007         unsigned int i;
1008         size_t len;
1009         size_t count = iov_iter_count(iter);
1010         unsigned int saved_len;
1011         size_t start;
1012         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
1013         struct page **pages = NULL;
1014         struct bio_vec *bv = NULL;
1015
1016         if (iov_iter_is_kvec(iter)) {
1017                 memcpy(&ctx->iter, iter, sizeof(*iter));
1018                 ctx->len = count;
1019                 iov_iter_advance(iter, count);
1020                 return 0;
1021         }
1022
1023         if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
1024                 bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
1025
1026         if (!bv) {
1027                 bv = vmalloc(array_size(max_pages, sizeof(*bv)));
1028                 if (!bv)
1029                         return -ENOMEM;
1030         }
1031
1032         if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
1033                 pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
1034
1035         if (!pages) {
1036                 pages = vmalloc(array_size(max_pages, sizeof(*pages)));
1037                 if (!pages) {
1038                         kvfree(bv);
1039                         return -ENOMEM;
1040                 }
1041         }
1042
1043         saved_len = count;
1044
1045         while (count && npages < max_pages) {
1046                 rc = iov_iter_get_pages2(iter, pages, count, max_pages, &start);
1047                 if (rc < 0) {
1048                         cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc);
1049                         break;
1050                 }
1051
1052                 if (rc > count) {
1053                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
1054                                  count);
1055                         break;
1056                 }
1057
1058                 count -= rc;
1059                 rc += start;
1060                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
1061
1062                 if (npages + cur_npages > max_pages) {
1063                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
1064                                  npages + cur_npages, max_pages);
1065                         break;
1066                 }
1067
1068                 for (i = 0; i < cur_npages; i++) {
1069                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
1070                         bv[npages + i].bv_page = pages[i];
1071                         bv[npages + i].bv_offset = start;
1072                         bv[npages + i].bv_len = len - start;
1073                         rc -= len;
1074                         start = 0;
1075                 }
1076
1077                 npages += cur_npages;
1078         }
1079
1080         kvfree(pages);
1081         ctx->bv = bv;
1082         ctx->len = saved_len - count;
1083         ctx->npages = npages;
1084         iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
1085         return 0;
1086 }
1087
1088 /**
1089  * cifs_alloc_hash - allocate hash and hash context together
1090  * @name: The name of the crypto hash algo
1091  * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
1092  *
1093  * The caller has to make sure @sdesc is initialized to either NULL or
1094  * a valid context. It can be freed via cifs_free_hash().
1095  */
1096 int
1097 cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
1098 {
1099         int rc = 0;
1100         struct crypto_shash *alg = NULL;
1101
1102         if (*sdesc)
1103                 return 0;
1104
1105         alg = crypto_alloc_shash(name, 0, 0);
1106         if (IS_ERR(alg)) {
1107                 cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
1108                 rc = PTR_ERR(alg);
1109                 *sdesc = NULL;
1110                 return rc;
1111         }
1112
1113         *sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
1114         if (*sdesc == NULL) {
1115                 cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
1116                 crypto_free_shash(alg);
1117                 return -ENOMEM;
1118         }
1119
1120         (*sdesc)->tfm = alg;
1121         return 0;
1122 }
1123
1124 /**
1125  * cifs_free_hash - free hash and hash context together
1126  * @sdesc: Where to find the pointer to the hash TFM
1127  *
1128  * Freeing a NULL descriptor is safe.
1129  */
1130 void
1131 cifs_free_hash(struct shash_desc **sdesc)
1132 {
1133         if (unlikely(!sdesc) || !*sdesc)
1134                 return;
1135
1136         if ((*sdesc)->tfm) {
1137                 crypto_free_shash((*sdesc)->tfm);
1138                 (*sdesc)->tfm = NULL;
1139         }
1140
1141         kfree_sensitive(*sdesc);
1142         *sdesc = NULL;
1143 }
1144
1145 /**
1146  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
1147  * @rqst: The request descriptor
1148  * @page: The index of the page to query
1149  * @len: Where to store the length for this page:
1150  * @offset: Where to store the offset for this page
1151  */
1152 void rqst_page_get_length(const struct smb_rqst *rqst, unsigned int page,
1153                           unsigned int *len, unsigned int *offset)
1154 {
1155         *len = rqst->rq_pagesz;
1156         *offset = (page == 0) ? rqst->rq_offset : 0;
1157
1158         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
1159                 *len = rqst->rq_tailsz;
1160         else if (page == 0)
1161                 *len = rqst->rq_pagesz - rqst->rq_offset;
1162 }
1163
1164 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1165 {
1166         const char *end;
1167
1168         /* skip initial slashes */
1169         while (*unc && (*unc == '\\' || *unc == '/'))
1170                 unc++;
1171
1172         end = unc;
1173
1174         while (*end && !(*end == '\\' || *end == '/'))
1175                 end++;
1176
1177         *h = unc;
1178         *len = end - unc;
1179 }
1180
1181 /**
1182  * copy_path_name - copy src path to dst, possibly truncating
1183  * @dst: The destination buffer
1184  * @src: The source name
1185  *
1186  * returns number of bytes written (including trailing nul)
1187  */
1188 int copy_path_name(char *dst, const char *src)
1189 {
1190         int name_len;
1191
1192         /*
1193          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1194          * will truncate and strlen(dst) will be PATH_MAX-1
1195          */
1196         name_len = strscpy(dst, src, PATH_MAX);
1197         if (WARN_ON_ONCE(name_len < 0))
1198                 name_len = PATH_MAX-1;
1199
1200         /* we count the trailing nul */
1201         name_len++;
1202         return name_len;
1203 }
1204
1205 struct super_cb_data {
1206         void *data;
1207         struct super_block *sb;
1208 };
1209
1210 static void tcp_super_cb(struct super_block *sb, void *arg)
1211 {
1212         struct super_cb_data *sd = arg;
1213         struct TCP_Server_Info *server = sd->data;
1214         struct cifs_sb_info *cifs_sb;
1215         struct cifs_tcon *tcon;
1216
1217         if (sd->sb)
1218                 return;
1219
1220         cifs_sb = CIFS_SB(sb);
1221         tcon = cifs_sb_master_tcon(cifs_sb);
1222         if (tcon->ses->server == server)
1223                 sd->sb = sb;
1224 }
1225
1226 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1227                                             void *data)
1228 {
1229         struct super_cb_data sd = {
1230                 .data = data,
1231                 .sb = NULL,
1232         };
1233         struct file_system_type **fs_type = (struct file_system_type *[]) {
1234                 &cifs_fs_type, &smb3_fs_type, NULL,
1235         };
1236
1237         for (; *fs_type; fs_type++) {
1238                 iterate_supers_type(*fs_type, f, &sd);
1239                 if (sd.sb) {
1240                         /*
1241                          * Grab an active reference in order to prevent automounts (DFS links)
1242                          * of expiring and then freeing up our cifs superblock pointer while
1243                          * we're doing failover.
1244                          */
1245                         cifs_sb_active(sd.sb);
1246                         return sd.sb;
1247                 }
1248         }
1249         return ERR_PTR(-EINVAL);
1250 }
1251
1252 static void __cifs_put_super(struct super_block *sb)
1253 {
1254         if (!IS_ERR_OR_NULL(sb))
1255                 cifs_sb_deactive(sb);
1256 }
1257
1258 struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server)
1259 {
1260         return __cifs_get_super(tcp_super_cb, server);
1261 }
1262
1263 void cifs_put_tcp_super(struct super_block *sb)
1264 {
1265         __cifs_put_super(sb);
1266 }
1267
1268 #ifdef CONFIG_CIFS_DFS_UPCALL
1269 int match_target_ip(struct TCP_Server_Info *server,
1270                     const char *share, size_t share_len,
1271                     bool *result)
1272 {
1273         int rc;
1274         char *target, *tip = NULL;
1275         struct sockaddr tipaddr;
1276
1277         *result = false;
1278
1279         target = kzalloc(share_len + 3, GFP_KERNEL);
1280         if (!target) {
1281                 rc = -ENOMEM;
1282                 goto out;
1283         }
1284
1285         scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1286
1287         cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1288
1289         rc = dns_resolve_server_name_to_ip(target, &tip, NULL);
1290         if (rc < 0)
1291                 goto out;
1292
1293         cifs_dbg(FYI, "%s: target ip: %s\n", __func__, tip);
1294
1295         if (!cifs_convert_address(&tipaddr, tip, strlen(tip))) {
1296                 cifs_dbg(VFS, "%s: failed to convert target ip address\n",
1297                          __func__);
1298                 rc = -EINVAL;
1299                 goto out;
1300         }
1301
1302         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr,
1303                                     &tipaddr);
1304         cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1305         rc = 0;
1306
1307 out:
1308         kfree(target);
1309         kfree(tip);
1310
1311         return rc;
1312 }
1313
1314 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1315 {
1316         kfree(cifs_sb->prepath);
1317
1318         if (prefix && *prefix) {
1319                 cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
1320                 if (!cifs_sb->prepath)
1321                         return -ENOMEM;
1322
1323                 convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1324         } else
1325                 cifs_sb->prepath = NULL;
1326
1327         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1328         return 0;
1329 }
1330
1331 /*
1332  * Handle weird Windows SMB server behaviour. It responds with
1333  * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
1334  * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
1335  * non-ASCII unicode symbols.
1336  */
1337 int cifs_inval_name_dfs_link_error(const unsigned int xid,
1338                                    struct cifs_tcon *tcon,
1339                                    struct cifs_sb_info *cifs_sb,
1340                                    const char *full_path,
1341                                    bool *islink)
1342 {
1343         struct cifs_ses *ses = tcon->ses;
1344         size_t len;
1345         char *path;
1346         char *ref_path;
1347
1348         *islink = false;
1349
1350         /*
1351          * Fast path - skip check when @full_path doesn't have a prefix path to
1352          * look up or tcon is not DFS.
1353          */
1354         if (strlen(full_path) < 2 || !cifs_sb ||
1355             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
1356             !is_tcon_dfs(tcon) || !ses->server->origin_fullpath)
1357                 return 0;
1358
1359         /*
1360          * Slow path - tcon is DFS and @full_path has prefix path, so attempt
1361          * to get a referral to figure out whether it is an DFS link.
1362          */
1363         len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
1364         path = kmalloc(len, GFP_KERNEL);
1365         if (!path)
1366                 return -ENOMEM;
1367
1368         scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
1369         ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
1370                                             cifs_remap(cifs_sb));
1371         kfree(path);
1372
1373         if (IS_ERR(ref_path)) {
1374                 if (PTR_ERR(ref_path) != -EINVAL)
1375                         return PTR_ERR(ref_path);
1376         } else {
1377                 struct dfs_info3_param *refs = NULL;
1378                 int num_refs = 0;
1379
1380                 /*
1381                  * XXX: we are not using dfs_cache_find() here because we might
1382                  * end filling all the DFS cache and thus potentially
1383                  * removing cached DFS targets that the client would eventually
1384                  * need during failover.
1385                  */
1386                 if (ses->server->ops->get_dfs_refer &&
1387                     !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
1388                                                      &num_refs, cifs_sb->local_nls,
1389                                                      cifs_remap(cifs_sb)))
1390                         *islink = refs[0].server_type == DFS_TYPE_LINK;
1391                 free_dfs_info_array(refs, num_refs);
1392                 kfree(ref_path);
1393         }
1394         return 0;
1395 }
1396 #endif
1397
1398 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
1399 {
1400         int timeout = 10;
1401         int rc;
1402
1403         spin_lock(&server->srv_lock);
1404         if (server->tcpStatus != CifsNeedReconnect) {
1405                 spin_unlock(&server->srv_lock);
1406                 return 0;
1407         }
1408         timeout *= server->nr_targets;
1409         spin_unlock(&server->srv_lock);
1410
1411         /*
1412          * Give demultiplex thread up to 10 seconds to each target available for
1413          * reconnect -- should be greater than cifs socket timeout which is 7
1414          * seconds.
1415          *
1416          * On "soft" mounts we wait once. Hard mounts keep retrying until
1417          * process is killed or server comes back on-line.
1418          */
1419         do {
1420                 rc = wait_event_interruptible_timeout(server->response_q,
1421                                                       (server->tcpStatus != CifsNeedReconnect),
1422                                                       timeout * HZ);
1423                 if (rc < 0) {
1424                         cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
1425                                  __func__);
1426                         return -ERESTARTSYS;
1427                 }
1428
1429                 /* are we still trying to reconnect? */
1430                 spin_lock(&server->srv_lock);
1431                 if (server->tcpStatus != CifsNeedReconnect) {
1432                         spin_unlock(&server->srv_lock);
1433                         return 0;
1434                 }
1435                 spin_unlock(&server->srv_lock);
1436         } while (retry);
1437
1438         cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
1439         return -EHOSTDOWN;
1440 }