fs/cifs/smb2misc.c

   1 /*
   2  *   fs/cifs/smb2misc.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2011
   5  *                 Etersoft, 2012
   6  *   Author(s): Steve French (sfrench@us.ibm.com)
   7  *              Pavel Shilovsky (pshilovsky@samba.org) 2012
   8  *
   9  *   This library is free software; you can redistribute it and/or modify
  10  *   it under the terms of the GNU Lesser General Public License as published
  11  *   by the Free Software Foundation; either version 2.1 of the License, or
  12  *   (at your option) any later version.
  13  *
  14  *   This library is distributed in the hope that it will be useful,
  15  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  17  *   the GNU Lesser General Public License for more details.
  18  *
  19  *   You should have received a copy of the GNU Lesser General Public License
  20  *   along with this library; if not, write to the Free Software
  21  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22  */
  23 #include <linux/ctype.h>
  24 #include "smb2pdu.h"
  25 #include "cifsglob.h"
  26 #include "cifsproto.h"
  27 #include "smb2proto.h"
  28 #include "cifs_debug.h"
  29 #include "cifs_unicode.h"
  30 #include "smb2status.h"
  31
  32 static int
  33 check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
  34 {
  35         __u64 wire_mid = le64_to_cpu(hdr->MessageId);
  36
  37         /*
  38          * Make sure that this really is an SMB, that it is a response,
  39          * and that the message ids match.
  40          */
  41         if ((hdr->ProtocolId == SMB2_PROTO_NUMBER) &&
  42             (mid == wire_mid)) {
  43                 if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
  44                         return 0;
  45                 else {
  46                         /* only one valid case where server sends us request */
  47                         if (hdr->Command == SMB2_OPLOCK_BREAK)
  48                                 return 0;
  49                         else
  50                                 cifs_dbg(VFS, "Received Request not response\n");
  51                 }
  52         } else { /* bad signature or mid */
  53                 if (hdr->ProtocolId != SMB2_PROTO_NUMBER)
  54                         cifs_dbg(VFS, "Bad protocol string signature header %x\n",
  55                                  le32_to_cpu(hdr->ProtocolId));
  56                 if (mid != wire_mid)
  57                         cifs_dbg(VFS, "Mids do not match: %llu and %llu\n",
  58                                  mid, wire_mid);
  59         }
  60         cifs_dbg(VFS, "Bad SMB detected. The Mid=%llu\n", wire_mid);
  61         return 1;
  62 }
  63
  64 /*
  65  *  The following table defines the expected "StructureSize" of SMB2 responses
  66  *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS responses.
  67  *
  68  *  Note that commands are defined in smb2pdu.h in le16 but the array below is
  69  *  indexed by command in host byte order
  70  */
  71 static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
  72         /* SMB2_NEGOTIATE */ cpu_to_le16(65),
  73         /* SMB2_SESSION_SETUP */ cpu_to_le16(9),
  74         /* SMB2_LOGOFF */ cpu_to_le16(4),
  75         /* SMB2_TREE_CONNECT */ cpu_to_le16(16),
  76         /* SMB2_TREE_DISCONNECT */ cpu_to_le16(4),
  77         /* SMB2_CREATE */ cpu_to_le16(89),
  78         /* SMB2_CLOSE */ cpu_to_le16(60),
  79         /* SMB2_FLUSH */ cpu_to_le16(4),
  80         /* SMB2_READ */ cpu_to_le16(17),
  81         /* SMB2_WRITE */ cpu_to_le16(17),
  82         /* SMB2_LOCK */ cpu_to_le16(4),
  83         /* SMB2_IOCTL */ cpu_to_le16(49),
  84         /* BB CHECK this ... not listed in documentation */
  85         /* SMB2_CANCEL */ cpu_to_le16(0),
  86         /* SMB2_ECHO */ cpu_to_le16(4),
  87         /* SMB2_QUERY_DIRECTORY */ cpu_to_le16(9),
  88         /* SMB2_CHANGE_NOTIFY */ cpu_to_le16(9),
  89         /* SMB2_QUERY_INFO */ cpu_to_le16(9),
  90         /* SMB2_SET_INFO */ cpu_to_le16(2),
  91         /* BB FIXME can also be 44 for lease break */
  92         /* SMB2_OPLOCK_BREAK */ cpu_to_le16(24)
  93 };
  94
  95 int
  96 smb2_check_message(char *buf, unsigned int length, struct TCP_Server_Info *srvr)
  97 {
  98         struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
  99         struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
 100         __u64 mid;
 101         __u32 len = get_rfc1002_length(buf);
 102         __u32 clc_len;  /* calculated length */
 103         int command;
 104
 105         /* BB disable following printk later */
 106         cifs_dbg(FYI, "%s length: 0x%x, smb_buf_length: 0x%x\n",
 107                  __func__, length, len);
 108
 109         /*
 110          * Add function to do table lookup of StructureSize by command
 111          * ie Validate the wct via smb2_struct_sizes table above
 112          */
 113
 114         if (hdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM) {
 115                 struct smb2_transform_hdr *thdr =
 116                         (struct smb2_transform_hdr *)buf;
 117                 struct cifs_ses *ses = NULL;
 118                 struct list_head *tmp;
 119
 120                 /* decrypt frame now that it is completely read in */
 121                 spin_lock(&cifs_tcp_ses_lock);
 122                 list_for_each(tmp, &srvr->smb_ses_list) {
 123                         ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 124                         if (ses->Suid == thdr->SessionId)
 125                                 break;
 126
 127                         ses = NULL;
 128                 }
 129                 spin_unlock(&cifs_tcp_ses_lock);
 130                 if (ses == NULL) {
 131                         cifs_dbg(VFS, "no decryption - session id not found\n");
 132                         return 1;
 133                 }
 134         }
 135
 136
 137         mid = le64_to_cpu(hdr->MessageId);
 138         if (length < sizeof(struct smb2_pdu)) {
 139                 if ((length >= sizeof(struct smb2_hdr)) && (hdr->Status != 0)) {
 140                         pdu->StructureSize2 = 0;
 141                         /*
 142                          * As with SMB/CIFS, on some error cases servers may
 143                          * not return wct properly
 144                          */
 145                         return 0;
 146                 } else {
 147                         cifs_dbg(VFS, "Length less than SMB header size\n");
 148                 }
 149                 return 1;
 150         }
 151         if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
 152                 cifs_dbg(VFS, "SMB length greater than maximum, mid=%llu\n",
 153                          mid);
 154                 return 1;
 155         }
 156
 157         if (check_smb2_hdr(hdr, mid))
 158                 return 1;
 159
 160         if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
 161                 cifs_dbg(VFS, "Illegal structure size %u\n",
 162                          le16_to_cpu(hdr->StructureSize));
 163                 return 1;
 164         }
 165
 166         command = le16_to_cpu(hdr->Command);
 167         if (command >= NUMBER_OF_SMB2_COMMANDS) {
 168                 cifs_dbg(VFS, "Illegal SMB2 command %d\n", command);
 169                 return 1;
 170         }
 171
 172         if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
 173                 if (command != SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0 ||
 174                     pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2)) {
 175                         /* error packets have 9 byte structure size */
 176                         cifs_dbg(VFS, "Illegal response size %u for command %d\n",
 177                                  le16_to_cpu(pdu->StructureSize2), command);
 178                         return 1;
 179                 } else if (command == SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0)
 180                            && (le16_to_cpu(pdu->StructureSize2) != 44)
 181                            && (le16_to_cpu(pdu->StructureSize2) != 36)) {
 182                         /* special case for SMB2.1 lease break message */
 183                         cifs_dbg(VFS, "Illegal response size %d for oplock break\n",
 184                                  le16_to_cpu(pdu->StructureSize2));
 185                         return 1;
 186                 }
 187         }
 188
 189         if (4 + len != length) {
 190                 cifs_dbg(VFS, "Total length %u RFC1002 length %u mismatch mid %llu\n",
 191                          length, 4 + len, mid);
 192                 return 1;
 193         }
 194
 195         clc_len = smb2_calc_size(hdr);
 196
 197         if (4 + len != clc_len) {
 198                 cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
 199                          clc_len, 4 + len, mid);
 200                 /* create failed on symlink */
 201                 if (command == SMB2_CREATE_HE &&
 202                     hdr->Status == STATUS_STOPPED_ON_SYMLINK)
 203                         return 0;
 204                 /* Windows 7 server returns 24 bytes more */
 205                 if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
 206                         return 0;
 207                 /* server can return one byte more due to implied bcc[0] */
 208                 if (clc_len == 4 + len + 1)
 209                         return 0;
 210
 211                 /*
 212                  * MacOS server pads after SMB2.1 write response with 3 bytes
 213                  * of junk. Other servers match RFC1001 len to actual
 214                  * SMB2/SMB3 frame length (header + smb2 response specific data)
 215                  * Log the server error (once), but allow it and continue
 216                  * since the frame is parseable.
 217                  */
 218                 if (clc_len < 4 /* RFC1001 header size */ + len) {
 219                         printk_once(KERN_WARNING
 220                                 "SMB2 server sent bad RFC1001 len %d not %d\n",
 221                                 len, clc_len - 4);
 222                         return 0;
 223                 }
 224
 225                 return 1;
 226         }
 227         return 0;
 228 }
 229
 230 /*
 231  * The size of the variable area depends on the offset and length fields
 232  * located in different fields for various SMB2 responses. SMB2 responses
 233  * with no variable length info, show an offset of zero for the offset field.
 234  */
 235 static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
 236         /* SMB2_NEGOTIATE */ true,
 237         /* SMB2_SESSION_SETUP */ true,
 238         /* SMB2_LOGOFF */ false,
 239         /* SMB2_TREE_CONNECT */ false,
 240         /* SMB2_TREE_DISCONNECT */ false,
 241         /* SMB2_CREATE */ true,
 242         /* SMB2_CLOSE */ false,
 243         /* SMB2_FLUSH */ false,
 244         /* SMB2_READ */ true,
 245         /* SMB2_WRITE */ false,
 246         /* SMB2_LOCK */ false,
 247         /* SMB2_IOCTL */ true,
 248         /* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
 249         /* SMB2_ECHO */ false,
 250         /* SMB2_QUERY_DIRECTORY */ true,
 251         /* SMB2_CHANGE_NOTIFY */ true,
 252         /* SMB2_QUERY_INFO */ true,
 253         /* SMB2_SET_INFO */ false,
 254         /* SMB2_OPLOCK_BREAK */ false
 255 };
 256
 257 /*
 258  * Returns the pointer to the beginning of the data area. Length of the data
 259  * area and the offset to it (from the beginning of the smb are also returned.
 260  */
 261 char *
 262 smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
 263 {
 264         *off = 0;
 265         *len = 0;
 266
 267         /* error responses do not have data area */
 268         if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
 269             (((struct smb2_err_rsp *)hdr)->StructureSize) ==
 270                                                 SMB2_ERROR_STRUCTURE_SIZE2)
 271                 return NULL;
 272
 273         /*
 274          * Following commands have data areas so we have to get the location
 275          * of the data buffer offset and data buffer length for the particular
 276          * command.
 277          */
 278         switch (hdr->Command) {
 279         case SMB2_NEGOTIATE:
 280                 *off = le16_to_cpu(
 281                     ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferOffset);
 282                 *len = le16_to_cpu(
 283                     ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferLength);
 284                 break;
 285         case SMB2_SESSION_SETUP:
 286                 *off = le16_to_cpu(
 287                     ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferOffset);
 288                 *len = le16_to_cpu(
 289                     ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferLength);
 290                 break;
 291         case SMB2_CREATE:
 292                 *off = le32_to_cpu(
 293                     ((struct smb2_create_rsp *)hdr)->CreateContextsOffset);
 294                 *len = le32_to_cpu(
 295                     ((struct smb2_create_rsp *)hdr)->CreateContextsLength);
 296                 break;
 297         case SMB2_QUERY_INFO:
 298                 *off = le16_to_cpu(
 299                     ((struct smb2_query_info_rsp *)hdr)->OutputBufferOffset);
 300                 *len = le32_to_cpu(
 301                     ((struct smb2_query_info_rsp *)hdr)->OutputBufferLength);
 302                 break;
 303         case SMB2_READ:
 304                 *off = ((struct smb2_read_rsp *)hdr)->DataOffset;
 305                 *len = le32_to_cpu(((struct smb2_read_rsp *)hdr)->DataLength);
 306                 break;
 307         case SMB2_QUERY_DIRECTORY:
 308                 *off = le16_to_cpu(
 309                   ((struct smb2_query_directory_rsp *)hdr)->OutputBufferOffset);
 310                 *len = le32_to_cpu(
 311                   ((struct smb2_query_directory_rsp *)hdr)->OutputBufferLength);
 312                 break;
 313         case SMB2_IOCTL:
 314                 *off = le32_to_cpu(
 315                   ((struct smb2_ioctl_rsp *)hdr)->OutputOffset);
 316                 *len = le32_to_cpu(((struct smb2_ioctl_rsp *)hdr)->OutputCount);
 317                 break;
 318         case SMB2_CHANGE_NOTIFY:
 319         default:
 320                 /* BB FIXME for unimplemented cases above */
 321                 cifs_dbg(VFS, "no length check for command\n");
 322                 break;
 323         }
 324
 325         /*
 326          * Invalid length or offset probably means data area is invalid, but
 327          * we have little choice but to ignore the data area in this case.
 328          */
 329         if (*off > 4096) {
 330                 cifs_dbg(VFS, "offset %d too large, data area ignored\n", *off);
 331                 *len = 0;
 332                 *off = 0;
 333         } else if (*off < 0) {
 334                 cifs_dbg(VFS, "negative offset %d to data invalid ignore data area\n",
 335                          *off);
 336                 *off = 0;
 337                 *len = 0;
 338         } else if (*len < 0) {
 339                 cifs_dbg(VFS, "negative data length %d invalid, data area ignored\n",
 340                          *len);
 341                 *len = 0;
 342         } else if (*len > 128 * 1024) {
 343                 cifs_dbg(VFS, "data area larger than 128K: %d\n", *len);
 344                 *len = 0;
 345         }
 346
 347         /* return pointer to beginning of data area, ie offset from SMB start */
 348         if ((*off != 0) && (*len != 0))
 349                 return (char *)(&hdr->ProtocolId) + *off;
 350         else
 351                 return NULL;
 352 }
 353
 354 /*
 355  * Calculate the size of the SMB message based on the fixed header
 356  * portion, the number of word parameters and the data portion of the message.
 357  */
 358 unsigned int
 359 smb2_calc_size(void *buf)
 360 {
 361         struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 362         struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
 363         int offset; /* the offset from the beginning of SMB to data area */
 364         int data_length; /* the length of the variable length data area */
 365         /* Structure Size has already been checked to make sure it is 64 */
 366         int len = 4 + le16_to_cpu(pdu->hdr.StructureSize);
 367
 368         /*
 369          * StructureSize2, ie length of fixed parameter area has already
 370          * been checked to make sure it is the correct length.
 371          */
 372         len += le16_to_cpu(pdu->StructureSize2);
 373
 374         if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
 375                 goto calc_size_exit;
 376
 377         smb2_get_data_area_len(&offset, &data_length, hdr);
 378         cifs_dbg(FYI, "SMB2 data length %d offset %d\n", data_length, offset);
 379
 380         if (data_length > 0) {
 381                 /*
 382                  * Check to make sure that data area begins after fixed area,
 383                  * Note that last byte of the fixed area is part of data area
 384                  * for some commands, typically those with odd StructureSize,
 385                  * so we must add one to the calculation (and 4 to account for
 386                  * the size of the RFC1001 hdr.
 387                  */
 388                 if (offset + 4 + 1 < len) {
 389                         cifs_dbg(VFS, "data area offset %d overlaps SMB2 header %d\n",
 390                                  offset + 4 + 1, len);
 391                         data_length = 0;
 392                 } else {
 393                         len = 4 + offset + data_length;
 394                 }
 395         }
 396 calc_size_exit:
 397         cifs_dbg(FYI, "SMB2 len %d\n", len);
 398         return len;
 399 }
 400
 401 /* Note: caller must free return buffer */
 402 __le16 *
 403 cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
 404 {
 405         int len;
 406         const char *start_of_path;
 407         __le16 *to;
 408         int map_type;
 409
 410         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
 411                 map_type = SFM_MAP_UNI_RSVD;
 412         else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
 413                 map_type = SFU_MAP_UNI_RSVD;
 414         else
 415                 map_type = NO_MAP_UNI_RSVD;
 416
 417         /* Windows doesn't allow paths beginning with \ */
 418         if (from[0] == '\\')
 419                 start_of_path = from + 1;
 420         else
 421                 start_of_path = from;
 422         to = cifs_strndup_to_utf16(start_of_path, PATH_MAX, &len,
 423                                    cifs_sb->local_nls, map_type);
 424         return to;
 425 }
 426
 427 __le32
 428 smb2_get_lease_state(struct cifsInodeInfo *cinode)
 429 {
 430         __le32 lease = 0;
 431
 432         if (CIFS_CACHE_WRITE(cinode))
 433                 lease |= SMB2_LEASE_WRITE_CACHING;
 434         if (CIFS_CACHE_HANDLE(cinode))
 435                 lease |= SMB2_LEASE_HANDLE_CACHING;
 436         if (CIFS_CACHE_READ(cinode))
 437                 lease |= SMB2_LEASE_READ_CACHING;
 438         return lease;
 439 }
 440
 441 struct smb2_lease_break_work {
 442         struct work_struct lease_break;
 443         struct tcon_link *tlink;
 444         __u8 lease_key[16];
 445         __le32 lease_state;
 446 };
 447
 448 static void
 449 cifs_ses_oplock_break(struct work_struct *work)
 450 {
 451         struct smb2_lease_break_work *lw = container_of(work,
 452                                 struct smb2_lease_break_work, lease_break);
 453         int rc;
 454
 455         rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
 456                               lw->lease_state);
 457         cifs_dbg(FYI, "Lease release rc %d\n", rc);
 458         cifs_put_tlink(lw->tlink);
 459         kfree(lw);
 460 }
 461
 462 static bool
 463 smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
 464                     struct smb2_lease_break_work *lw)
 465 {
 466         bool found;
 467         __u8 lease_state;
 468         struct list_head *tmp;
 469         struct cifsFileInfo *cfile;
 470         struct TCP_Server_Info *server = tcon->ses->server;
 471         struct cifs_pending_open *open;
 472         struct cifsInodeInfo *cinode;
 473         int ack_req = le32_to_cpu(rsp->Flags &
 474                                   SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED);
 475
 476         lease_state = le32_to_cpu(rsp->NewLeaseState);
 477
 478         list_for_each(tmp, &tcon->openFileList) {
 479                 cfile = list_entry(tmp, struct cifsFileInfo, tlist);
 480                 cinode = CIFS_I(d_inode(cfile->dentry));
 481
 482                 if (memcmp(cinode->lease_key, rsp->LeaseKey,
 483                                                         SMB2_LEASE_KEY_SIZE))
 484                         continue;
 485
 486                 cifs_dbg(FYI, "found in the open list\n");
 487                 cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
 488                          le32_to_cpu(rsp->NewLeaseState));
 489
 490                 server->ops->set_oplock_level(cinode, lease_state, 0, NULL);
 491
 492                 if (ack_req)
 493                         cfile->oplock_break_cancelled = false;
 494                 else
 495                         cfile->oplock_break_cancelled = true;
 496
 497                 queue_work(cifsiod_wq, &cfile->oplock_break);
 498                 kfree(lw);
 499                 return true;
 500         }
 501
 502         found = false;
 503         list_for_each_entry(open, &tcon->pending_opens, olist) {
 504                 if (memcmp(open->lease_key, rsp->LeaseKey,
 505                            SMB2_LEASE_KEY_SIZE))
 506                         continue;
 507
 508                 if (!found && ack_req) {
 509                         found = true;
 510                         memcpy(lw->lease_key, open->lease_key,
 511                                SMB2_LEASE_KEY_SIZE);
 512                         lw->tlink = cifs_get_tlink(open->tlink);
 513                         queue_work(cifsiod_wq, &lw->lease_break);
 514                 }
 515
 516                 cifs_dbg(FYI, "found in the pending open list\n");
 517                 cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
 518                          le32_to_cpu(rsp->NewLeaseState));
 519
 520                 open->oplock = lease_state;
 521         }
 522         return found;
 523 }
 524
 525 static bool
 526 smb2_is_valid_lease_break(char *buffer)
 527 {
 528         struct smb2_lease_break *rsp = (struct smb2_lease_break *)buffer;
 529         struct list_head *tmp, *tmp1, *tmp2;
 530         struct TCP_Server_Info *server;
 531         struct cifs_ses *ses;
 532         struct cifs_tcon *tcon;
 533         struct smb2_lease_break_work *lw;
 534
 535         lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
 536         if (!lw)
 537                 return false;
 538
 539         INIT_WORK(&lw->lease_break, cifs_ses_oplock_break);
 540         lw->lease_state = rsp->NewLeaseState;
 541
 542         cifs_dbg(FYI, "Checking for lease break\n");
 543
 544         /* look up tcon based on tid & uid */
 545         spin_lock(&cifs_tcp_ses_lock);
 546         list_for_each(tmp, &cifs_tcp_ses_list) {
 547                 server = list_entry(tmp, struct TCP_Server_Info, tcp_ses_list);
 548
 549                 list_for_each(tmp1, &server->smb_ses_list) {
 550                         ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);
 551
 552                         spin_lock(&cifs_file_list_lock);
 553                         list_for_each(tmp2, &ses->tcon_list) {
 554                                 tcon = list_entry(tmp2, struct cifs_tcon,
 555                                                   tcon_list);
 556                                 cifs_stats_inc(
 557                                     &tcon->stats.cifs_stats.num_oplock_brks);
 558                                 if (smb2_tcon_has_lease(tcon, rsp, lw)) {
 559                                         spin_unlock(&cifs_file_list_lock);
 560                                         spin_unlock(&cifs_tcp_ses_lock);
 561                                         return true;
 562                                 }
 563                         }
 564                         spin_unlock(&cifs_file_list_lock);
 565                 }
 566         }
 567         spin_unlock(&cifs_tcp_ses_lock);
 568         kfree(lw);
 569         cifs_dbg(FYI, "Can not process lease break - no lease matched\n");
 570         return false;
 571 }
 572
 573 bool
 574 smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 575 {
 576         struct smb2_oplock_break *rsp = (struct smb2_oplock_break *)buffer;
 577         struct list_head *tmp, *tmp1, *tmp2;
 578         struct cifs_ses *ses;
 579         struct cifs_tcon *tcon;
 580         struct cifsInodeInfo *cinode;
 581         struct cifsFileInfo *cfile;
 582
 583         cifs_dbg(FYI, "Checking for oplock break\n");
 584
 585         if (rsp->hdr.Command != SMB2_OPLOCK_BREAK)
 586                 return false;
 587
 588         if (rsp->StructureSize !=
 589                                 smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
 590                 if (le16_to_cpu(rsp->StructureSize) == 44)
 591                         return smb2_is_valid_lease_break(buffer);
 592                 else
 593                         return false;
 594         }
 595
 596         cifs_dbg(FYI, "oplock level 0x%x\n", rsp->OplockLevel);
 597
 598         /* look up tcon based on tid & uid */
 599         spin_lock(&cifs_tcp_ses_lock);
 600         list_for_each(tmp, &server->smb_ses_list) {
 601                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 602                 list_for_each(tmp1, &ses->tcon_list) {
 603                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 604
 605                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 606                         spin_lock(&cifs_file_list_lock);
 607                         list_for_each(tmp2, &tcon->openFileList) {
 608                                 cfile = list_entry(tmp2, struct cifsFileInfo,
 609                                                      tlist);
 610                                 if (rsp->PersistentFid !=
 611                                     cfile->fid.persistent_fid ||
 612                                     rsp->VolatileFid !=
 613                                     cfile->fid.volatile_fid)
 614                                         continue;
 615
 616                                 cifs_dbg(FYI, "file id match, oplock break\n");
 617                                 cinode = CIFS_I(d_inode(cfile->dentry));
 618
 619                                 if (!CIFS_CACHE_WRITE(cinode) &&
 620                                     rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
 621                                         cfile->oplock_break_cancelled = true;
 622                                 else
 623                                         cfile->oplock_break_cancelled = false;
 624
 625                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 626                                         &cinode->flags);
 627
 628                                 /*
 629                                  * Set flag if the server downgrades the oplock
 630                                  * to L2 else clear.
 631                                  */
 632                                 if (rsp->OplockLevel)
 633                                         set_bit(
 634                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 635                                            &cinode->flags);
 636                                 else
 637                                         clear_bit(
 638                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 639                                            &cinode->flags);
 640
 641                                 queue_work(cifsiod_wq, &cfile->oplock_break);
 642
 643                                 spin_unlock(&cifs_file_list_lock);
 644                                 spin_unlock(&cifs_tcp_ses_lock);
 645                                 return true;
 646                         }
 647                         spin_unlock(&cifs_file_list_lock);
 648                         spin_unlock(&cifs_tcp_ses_lock);
 649                         cifs_dbg(FYI, "No matching file for oplock break\n");
 650                         return true;
 651                 }
 652         }
 653         spin_unlock(&cifs_tcp_ses_lock);
 654         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 655         return false;
 656 }