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 /*              cifs_dbg(VFS, "Flags 0x%x Session Id %lld\n",
 121                          thdr->Flags, thdr->SessionId); */
 122
 123                 /* decrypt frame now that it is completely read in */
 124                 spin_lock(&cifs_tcp_ses_lock);
 125                 list_for_each(tmp, &srvr->smb_ses_list) {
 126                         ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 127                         if (ses->Suid == thdr->SessionId)
 128                                 break;
 129
 130                         ses = NULL;
 131                 }
 132                 spin_unlock(&cifs_tcp_ses_lock);
 133                 if (ses == NULL) {
 134                         cifs_dbg(VFS, "no decryption - session id not found\n");
 135                         return 1;
 136                 }
 137         }
 138
 139
 140         mid = le64_to_cpu(hdr->MessageId);
 141         if (length < sizeof(struct smb2_pdu)) {
 142                 if ((length >= sizeof(struct smb2_hdr)) && (hdr->Status != 0)) {
 143                         pdu->StructureSize2 = 0;
 144                         /*
 145                          * As with SMB/CIFS, on some error cases servers may
 146                          * not return wct properly
 147                          */
 148                         return 0;
 149                 } else {
 150                         cifs_dbg(VFS, "Length less than SMB header size\n");
 151                 }
 152                 return 1;
 153         }
 154         if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
 155                 cifs_dbg(VFS, "SMB length greater than maximum, mid=%llu\n",
 156                          mid);
 157                 return 1;
 158         }
 159
 160         if (check_smb2_hdr(hdr, mid))
 161                 return 1;
 162
 163         if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
 164                 cifs_dbg(VFS, "Illegal structure size %u\n",
 165                          le16_to_cpu(hdr->StructureSize));
 166                 return 1;
 167         }
 168
 169         command = le16_to_cpu(hdr->Command);
 170         if (command >= NUMBER_OF_SMB2_COMMANDS) {
 171                 cifs_dbg(VFS, "Illegal SMB2 command %d\n", command);
 172                 return 1;
 173         }
 174
 175         if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
 176                 if (command != SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0 ||
 177                     pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2)) {
 178                         /* error packets have 9 byte structure size */
 179                         cifs_dbg(VFS, "Illegal response size %u for command %d\n",
 180                                  le16_to_cpu(pdu->StructureSize2), command);
 181                         return 1;
 182                 } else if (command == SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0)
 183                            && (le16_to_cpu(pdu->StructureSize2) != 44)
 184                            && (le16_to_cpu(pdu->StructureSize2) != 36)) {
 185                         /* special case for SMB2.1 lease break message */
 186                         cifs_dbg(VFS, "Illegal response size %d for oplock break\n",
 187                                  le16_to_cpu(pdu->StructureSize2));
 188                         return 1;
 189                 }
 190         }
 191
 192         if (4 + len != length) {
 193                 cifs_dbg(VFS, "Total length %u RFC1002 length %u mismatch mid %llu\n",
 194                          length, 4 + len, mid);
 195                 return 1;
 196         }
 197
 198         clc_len = smb2_calc_size(hdr);
 199
 200         if (4 + len != clc_len) {
 201                 cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
 202                          clc_len, 4 + len, mid);
 203                 /* create failed on symlink */
 204                 if (command == SMB2_CREATE_HE &&
 205                     hdr->Status == STATUS_STOPPED_ON_SYMLINK)
 206                         return 0;
 207                 /* Windows 7 server returns 24 bytes more */
 208                 if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
 209                         return 0;
 210                 /* server can return one byte more due to implied bcc[0] */
 211                 if (clc_len == 4 + len + 1)
 212                         return 0;
 213
 214                 /*
 215                  * MacOS server pads after SMB2.1 write response with 3 bytes
 216                  * of junk. Other servers match RFC1001 len to actual
 217                  * SMB2/SMB3 frame length (header + smb2 response specific data)
 218                  * Log the server error (once), but allow it and continue
 219                  * since the frame is parseable.
 220                  */
 221                 if (clc_len < 4 /* RFC1001 header size */ + len) {
 222                         printk_once(KERN_WARNING
 223                                 "SMB2 server sent bad RFC1001 len %d not %d\n",
 224                                 len, clc_len - 4);
 225                         return 0;
 226                 }
 227
 228                 return 1;
 229         }
 230         return 0;
 231 }
 232
 233 /*
 234  * The size of the variable area depends on the offset and length fields
 235  * located in different fields for various SMB2 responses. SMB2 responses
 236  * with no variable length info, show an offset of zero for the offset field.
 237  */
 238 static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
 239         /* SMB2_NEGOTIATE */ true,
 240         /* SMB2_SESSION_SETUP */ true,
 241         /* SMB2_LOGOFF */ false,
 242         /* SMB2_TREE_CONNECT */ false,
 243         /* SMB2_TREE_DISCONNECT */ false,
 244         /* SMB2_CREATE */ true,
 245         /* SMB2_CLOSE */ false,
 246         /* SMB2_FLUSH */ false,
 247         /* SMB2_READ */ true,
 248         /* SMB2_WRITE */ false,
 249         /* SMB2_LOCK */ false,
 250         /* SMB2_IOCTL */ true,
 251         /* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
 252         /* SMB2_ECHO */ false,
 253         /* SMB2_QUERY_DIRECTORY */ true,
 254         /* SMB2_CHANGE_NOTIFY */ true,
 255         /* SMB2_QUERY_INFO */ true,
 256         /* SMB2_SET_INFO */ false,
 257         /* SMB2_OPLOCK_BREAK */ false
 258 };
 259
 260 /*
 261  * Returns the pointer to the beginning of the data area. Length of the data
 262  * area and the offset to it (from the beginning of the smb are also returned.
 263  */
 264 char *
 265 smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
 266 {
 267         *off = 0;
 268         *len = 0;
 269
 270         /* error responses do not have data area */
 271         if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
 272             (((struct smb2_err_rsp *)hdr)->StructureSize) ==
 273                                                 SMB2_ERROR_STRUCTURE_SIZE2)
 274                 return NULL;
 275
 276         /*
 277          * Following commands have data areas so we have to get the location
 278          * of the data buffer offset and data buffer length for the particular
 279          * command.
 280          */
 281         switch (hdr->Command) {
 282         case SMB2_NEGOTIATE:
 283                 *off = le16_to_cpu(
 284                     ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferOffset);
 285                 *len = le16_to_cpu(
 286                     ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferLength);
 287                 break;
 288         case SMB2_SESSION_SETUP:
 289                 *off = le16_to_cpu(
 290                     ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferOffset);
 291                 *len = le16_to_cpu(
 292                     ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferLength);
 293                 break;
 294         case SMB2_CREATE:
 295                 *off = le32_to_cpu(
 296                     ((struct smb2_create_rsp *)hdr)->CreateContextsOffset);
 297                 *len = le32_to_cpu(
 298                     ((struct smb2_create_rsp *)hdr)->CreateContextsLength);
 299                 break;
 300         case SMB2_QUERY_INFO:
 301                 *off = le16_to_cpu(
 302                     ((struct smb2_query_info_rsp *)hdr)->OutputBufferOffset);
 303                 *len = le32_to_cpu(
 304                     ((struct smb2_query_info_rsp *)hdr)->OutputBufferLength);
 305                 break;
 306         case SMB2_READ:
 307                 *off = ((struct smb2_read_rsp *)hdr)->DataOffset;
 308                 *len = le32_to_cpu(((struct smb2_read_rsp *)hdr)->DataLength);
 309                 break;
 310         case SMB2_QUERY_DIRECTORY:
 311                 *off = le16_to_cpu(
 312                   ((struct smb2_query_directory_rsp *)hdr)->OutputBufferOffset);
 313                 *len = le32_to_cpu(
 314                   ((struct smb2_query_directory_rsp *)hdr)->OutputBufferLength);
 315                 break;
 316         case SMB2_IOCTL:
 317                 *off = le32_to_cpu(
 318                   ((struct smb2_ioctl_rsp *)hdr)->OutputOffset);
 319                 *len = le32_to_cpu(((struct smb2_ioctl_rsp *)hdr)->OutputCount);
 320                 break;
 321         case SMB2_CHANGE_NOTIFY:
 322         default:
 323                 /* BB FIXME for unimplemented cases above */
 324                 cifs_dbg(VFS, "no length check for command\n");
 325                 break;
 326         }
 327
 328         /*
 329          * Invalid length or offset probably means data area is invalid, but
 330          * we have little choice but to ignore the data area in this case.
 331          */
 332         if (*off > 4096) {
 333                 cifs_dbg(VFS, "offset %d too large, data area ignored\n", *off);
 334                 *len = 0;
 335                 *off = 0;
 336         } else if (*off < 0) {
 337                 cifs_dbg(VFS, "negative offset %d to data invalid ignore data area\n",
 338                          *off);
 339                 *off = 0;
 340                 *len = 0;
 341         } else if (*len < 0) {
 342                 cifs_dbg(VFS, "negative data length %d invalid, data area ignored\n",
 343                          *len);
 344                 *len = 0;
 345         } else if (*len > 128 * 1024) {
 346                 cifs_dbg(VFS, "data area larger than 128K: %d\n", *len);
 347                 *len = 0;
 348         }
 349
 350         /* return pointer to beginning of data area, ie offset from SMB start */
 351         if ((*off != 0) && (*len != 0))
 352                 return (char *)(&hdr->ProtocolId) + *off;
 353         else
 354                 return NULL;
 355 }
 356
 357 /*
 358  * Calculate the size of the SMB message based on the fixed header
 359  * portion, the number of word parameters and the data portion of the message.
 360  */
 361 unsigned int
 362 smb2_calc_size(void *buf)
 363 {
 364         struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 365         struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
 366         int offset; /* the offset from the beginning of SMB to data area */
 367         int data_length; /* the length of the variable length data area */
 368         /* Structure Size has already been checked to make sure it is 64 */
 369         int len = 4 + le16_to_cpu(pdu->hdr.StructureSize);
 370
 371         /*
 372          * StructureSize2, ie length of fixed parameter area has already
 373          * been checked to make sure it is the correct length.
 374          */
 375         len += le16_to_cpu(pdu->StructureSize2);
 376
 377         if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
 378                 goto calc_size_exit;
 379
 380         smb2_get_data_area_len(&offset, &data_length, hdr);
 381         cifs_dbg(FYI, "SMB2 data length %d offset %d\n", data_length, offset);
 382
 383         if (data_length > 0) {
 384                 /*
 385                  * Check to make sure that data area begins after fixed area,
 386                  * Note that last byte of the fixed area is part of data area
 387                  * for some commands, typically those with odd StructureSize,
 388                  * so we must add one to the calculation (and 4 to account for
 389                  * the size of the RFC1001 hdr.
 390                  */
 391                 if (offset + 4 + 1 < len) {
 392                         cifs_dbg(VFS, "data area offset %d overlaps SMB2 header %d\n",
 393                                  offset + 4 + 1, len);
 394                         data_length = 0;
 395                 } else {
 396                         len = 4 + offset + data_length;
 397                 }
 398         }
 399 calc_size_exit:
 400         cifs_dbg(FYI, "SMB2 len %d\n", len);
 401         return len;
 402 }
 403
 404 /* Note: caller must free return buffer */
 405 __le16 *
 406 cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
 407 {
 408         int len;
 409         const char *start_of_path;
 410         __le16 *to;
 411         int map_type;
 412
 413         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
 414                 map_type = SFM_MAP_UNI_RSVD;
 415         else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
 416                 map_type = SFU_MAP_UNI_RSVD;
 417         else
 418                 map_type = NO_MAP_UNI_RSVD;
 419
 420         /* Windows doesn't allow paths beginning with \ */
 421         if (from[0] == '\\')
 422                 start_of_path = from + 1;
 423         else
 424                 start_of_path = from;
 425         to = cifs_strndup_to_utf16(start_of_path, PATH_MAX, &len,
 426                                    cifs_sb->local_nls, map_type);
 427         return to;
 428 }
 429
 430 __le32
 431 smb2_get_lease_state(struct cifsInodeInfo *cinode)
 432 {
 433         __le32 lease = 0;
 434
 435         if (CIFS_CACHE_WRITE(cinode))
 436                 lease |= SMB2_LEASE_WRITE_CACHING;
 437         if (CIFS_CACHE_HANDLE(cinode))
 438                 lease |= SMB2_LEASE_HANDLE_CACHING;
 439         if (CIFS_CACHE_READ(cinode))
 440                 lease |= SMB2_LEASE_READ_CACHING;
 441         return lease;
 442 }
 443
 444 struct smb2_lease_break_work {
 445         struct work_struct lease_break;
 446         struct tcon_link *tlink;
 447         __u8 lease_key[16];
 448         __le32 lease_state;
 449 };
 450
 451 static void
 452 cifs_ses_oplock_break(struct work_struct *work)
 453 {
 454         struct smb2_lease_break_work *lw = container_of(work,
 455                                 struct smb2_lease_break_work, lease_break);
 456         int rc;
 457
 458         rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
 459                               lw->lease_state);
 460         cifs_dbg(FYI, "Lease release rc %d\n", rc);
 461         cifs_put_tlink(lw->tlink);
 462         kfree(lw);
 463 }
 464
 465 static bool
 466 smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
 467                     struct smb2_lease_break_work *lw)
 468 {
 469         bool found;
 470         __u8 lease_state;
 471         struct list_head *tmp;
 472         struct cifsFileInfo *cfile;
 473         struct TCP_Server_Info *server = tcon->ses->server;
 474         struct cifs_pending_open *open;
 475         struct cifsInodeInfo *cinode;
 476         int ack_req = le32_to_cpu(rsp->Flags &
 477                                   SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED);
 478
 479         lease_state = le32_to_cpu(rsp->NewLeaseState);
 480
 481         list_for_each(tmp, &tcon->openFileList) {
 482                 cfile = list_entry(tmp, struct cifsFileInfo, tlist);
 483                 cinode = CIFS_I(d_inode(cfile->dentry));
 484
 485                 if (memcmp(cinode->lease_key, rsp->LeaseKey,
 486                                                         SMB2_LEASE_KEY_SIZE))
 487                         continue;
 488
 489                 cifs_dbg(FYI, "found in the open list\n");
 490                 cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
 491                          le32_to_cpu(rsp->NewLeaseState));
 492
 493                 server->ops->set_oplock_level(cinode, lease_state, 0, NULL);
 494
 495                 if (ack_req)
 496                         cfile->oplock_break_cancelled = false;
 497                 else
 498                         cfile->oplock_break_cancelled = true;
 499
 500                 queue_work(cifsiod_wq, &cfile->oplock_break);
 501                 kfree(lw);
 502                 return true;
 503         }
 504
 505         found = false;
 506         list_for_each_entry(open, &tcon->pending_opens, olist) {
 507                 if (memcmp(open->lease_key, rsp->LeaseKey,
 508                            SMB2_LEASE_KEY_SIZE))
 509                         continue;
 510
 511                 if (!found && ack_req) {
 512                         found = true;
 513                         memcpy(lw->lease_key, open->lease_key,
 514                                SMB2_LEASE_KEY_SIZE);
 515                         lw->tlink = cifs_get_tlink(open->tlink);
 516                         queue_work(cifsiod_wq, &lw->lease_break);
 517                 }
 518
 519                 cifs_dbg(FYI, "found in the pending open list\n");
 520                 cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
 521                          le32_to_cpu(rsp->NewLeaseState));
 522
 523                 open->oplock = lease_state;
 524         }
 525         return found;
 526 }
 527
 528 static bool
 529 smb2_is_valid_lease_break(char *buffer)
 530 {
 531         struct smb2_lease_break *rsp = (struct smb2_lease_break *)buffer;
 532         struct list_head *tmp, *tmp1, *tmp2;
 533         struct TCP_Server_Info *server;
 534         struct cifs_ses *ses;
 535         struct cifs_tcon *tcon;
 536         struct smb2_lease_break_work *lw;
 537
 538         lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
 539         if (!lw)
 540                 return false;
 541
 542         INIT_WORK(&lw->lease_break, cifs_ses_oplock_break);
 543         lw->lease_state = rsp->NewLeaseState;
 544
 545         cifs_dbg(FYI, "Checking for lease break\n");
 546
 547         /* look up tcon based on tid & uid */
 548         spin_lock(&cifs_tcp_ses_lock);
 549         list_for_each(tmp, &cifs_tcp_ses_list) {
 550                 server = list_entry(tmp, struct TCP_Server_Info, tcp_ses_list);
 551
 552                 list_for_each(tmp1, &server->smb_ses_list) {
 553                         ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);
 554
 555                         spin_lock(&cifs_file_list_lock);
 556                         list_for_each(tmp2, &ses->tcon_list) {
 557                                 tcon = list_entry(tmp2, struct cifs_tcon,
 558                                                   tcon_list);
 559                                 cifs_stats_inc(
 560                                     &tcon->stats.cifs_stats.num_oplock_brks);
 561                                 if (smb2_tcon_has_lease(tcon, rsp, lw)) {
 562                                         spin_unlock(&cifs_file_list_lock);
 563                                         spin_unlock(&cifs_tcp_ses_lock);
 564                                         return true;
 565                                 }
 566                         }
 567                         spin_unlock(&cifs_file_list_lock);
 568                 }
 569         }
 570         spin_unlock(&cifs_tcp_ses_lock);
 571         kfree(lw);
 572         cifs_dbg(FYI, "Can not process lease break - no lease matched\n");
 573         return false;
 574 }
 575
 576 bool
 577 smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 578 {
 579         struct smb2_oplock_break *rsp = (struct smb2_oplock_break *)buffer;
 580         struct list_head *tmp, *tmp1, *tmp2;
 581         struct cifs_ses *ses;
 582         struct cifs_tcon *tcon;
 583         struct cifsInodeInfo *cinode;
 584         struct cifsFileInfo *cfile;
 585
 586         cifs_dbg(FYI, "Checking for oplock break\n");
 587
 588         if (rsp->hdr.Command != SMB2_OPLOCK_BREAK)
 589                 return false;
 590
 591         if (rsp->StructureSize !=
 592                                 smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
 593                 if (le16_to_cpu(rsp->StructureSize) == 44)
 594                         return smb2_is_valid_lease_break(buffer);
 595                 else
 596                         return false;
 597         }
 598
 599         cifs_dbg(FYI, "oplock level 0x%x\n", rsp->OplockLevel);
 600
 601         /* look up tcon based on tid & uid */
 602         spin_lock(&cifs_tcp_ses_lock);
 603         list_for_each(tmp, &server->smb_ses_list) {
 604                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 605                 list_for_each(tmp1, &ses->tcon_list) {
 606                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 607
 608                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 609                         spin_lock(&cifs_file_list_lock);
 610                         list_for_each(tmp2, &tcon->openFileList) {
 611                                 cfile = list_entry(tmp2, struct cifsFileInfo,
 612                                                      tlist);
 613                                 if (rsp->PersistentFid !=
 614                                     cfile->fid.persistent_fid ||
 615                                     rsp->VolatileFid !=
 616                                     cfile->fid.volatile_fid)
 617                                         continue;
 618
 619                                 cifs_dbg(FYI, "file id match, oplock break\n");
 620                                 cinode = CIFS_I(d_inode(cfile->dentry));
 621
 622                                 if (!CIFS_CACHE_WRITE(cinode) &&
 623                                     rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
 624                                         cfile->oplock_break_cancelled = true;
 625                                 else
 626                                         cfile->oplock_break_cancelled = false;
 627
 628                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 629                                         &cinode->flags);
 630
 631                                 /*
 632                                  * Set flag if the server downgrades the oplock
 633                                  * to L2 else clear.
 634                                  */
 635                                 if (rsp->OplockLevel)
 636                                         set_bit(
 637                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 638                                            &cinode->flags);
 639                                 else
 640                                         clear_bit(
 641                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 642                                            &cinode->flags);
 643
 644                                 queue_work(cifsiod_wq, &cfile->oplock_break);
 645
 646                                 spin_unlock(&cifs_file_list_lock);
 647                                 spin_unlock(&cifs_tcp_ses_lock);
 648                                 return true;
 649                         }
 650                         spin_unlock(&cifs_file_list_lock);
 651                         spin_unlock(&cifs_tcp_ses_lock);
 652                         cifs_dbg(FYI, "No matching file for oplock break\n");
 653                         return true;
 654                 }
 655         }
 656         spin_unlock(&cifs_tcp_ses_lock);
 657         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 658         return false;
 659 }