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 ((*(__le32 *)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 (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
  54                         cifs_dbg(VFS, "Bad protocol string signature header %x\n",
  55                                  *(unsigned int *) 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)
  97 {
  98         struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
  99         struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
 100         __u64 mid = le64_to_cpu(hdr->MessageId);
 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 (length < sizeof(struct smb2_pdu)) {
 115                 if ((length >= sizeof(struct smb2_hdr)) && (hdr->Status != 0)) {
 116                         pdu->StructureSize2 = 0;
 117                         /*
 118                          * As with SMB/CIFS, on some error cases servers may
 119                          * not return wct properly
 120                          */
 121                         return 0;
 122                 } else {
 123                         cifs_dbg(VFS, "Length less than SMB header size\n");
 124                 }
 125                 return 1;
 126         }
 127         if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
 128                 cifs_dbg(VFS, "SMB length greater than maximum, mid=%llu\n",
 129                          mid);
 130                 return 1;
 131         }
 132
 133         if (check_smb2_hdr(hdr, mid))
 134                 return 1;
 135
 136         if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
 137                 cifs_dbg(VFS, "Illegal structure size %u\n",
 138                          le16_to_cpu(hdr->StructureSize));
 139                 return 1;
 140         }
 141
 142         command = le16_to_cpu(hdr->Command);
 143         if (command >= NUMBER_OF_SMB2_COMMANDS) {
 144                 cifs_dbg(VFS, "Illegal SMB2 command %d\n", command);
 145                 return 1;
 146         }
 147
 148         if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
 149                 if (command != SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0 ||
 150                     pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2)) {
 151                         /* error packets have 9 byte structure size */
 152                         cifs_dbg(VFS, "Illegal response size %u for command %d\n",
 153                                  le16_to_cpu(pdu->StructureSize2), command);
 154                         return 1;
 155                 } else if (command == SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0)
 156                            && (le16_to_cpu(pdu->StructureSize2) != 44)
 157                            && (le16_to_cpu(pdu->StructureSize2) != 36)) {
 158                         /* special case for SMB2.1 lease break message */
 159                         cifs_dbg(VFS, "Illegal response size %d for oplock break\n",
 160                                  le16_to_cpu(pdu->StructureSize2));
 161                         return 1;
 162                 }
 163         }
 164
 165         if (4 + len != length) {
 166                 cifs_dbg(VFS, "Total length %u RFC1002 length %u mismatch mid %llu\n",
 167                          length, 4 + len, mid);
 168                 return 1;
 169         }
 170
 171         clc_len = smb2_calc_size(hdr);
 172
 173         if (4 + len != clc_len) {
 174                 cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
 175                          clc_len, 4 + len, mid);
 176                 /* create failed on symlink */
 177                 if (command == SMB2_CREATE_HE &&
 178                     hdr->Status == STATUS_STOPPED_ON_SYMLINK)
 179                         return 0;
 180                 /* Windows 7 server returns 24 bytes more */
 181                 if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
 182                         return 0;
 183                 /* server can return one byte more due to implied bcc[0] */
 184                 if (clc_len == 4 + len + 1)
 185                         return 0;
 186
 187                 /*
 188                  * Some windows servers (win2016) will pad also the final
 189                  * PDU in a compound to 8 bytes.
 190                  */
 191                 if (((clc_len + 7) & ~7) == len)
 192                         return 0;
 193
 194                 /*
 195                  * MacOS server pads after SMB2.1 write response with 3 bytes
 196                  * of junk. Other servers match RFC1001 len to actual
 197                  * SMB2/SMB3 frame length (header + smb2 response specific data)
 198                  * Log the server error (once), but allow it and continue
 199                  * since the frame is parseable.
 200                  */
 201                 if (clc_len < 4 /* RFC1001 header size */ + len) {
 202                         printk_once(KERN_WARNING
 203                                 "SMB2 server sent bad RFC1001 len %d not %d\n",
 204                                 len, clc_len - 4);
 205                         return 0;
 206                 }
 207
 208                 return 1;
 209         }
 210         return 0;
 211 }
 212
 213 /*
 214  * The size of the variable area depends on the offset and length fields
 215  * located in different fields for various SMB2 responses. SMB2 responses
 216  * with no variable length info, show an offset of zero for the offset field.
 217  */
 218 static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
 219         /* SMB2_NEGOTIATE */ true,
 220         /* SMB2_SESSION_SETUP */ true,
 221         /* SMB2_LOGOFF */ false,
 222         /* SMB2_TREE_CONNECT */ false,
 223         /* SMB2_TREE_DISCONNECT */ false,
 224         /* SMB2_CREATE */ true,
 225         /* SMB2_CLOSE */ false,
 226         /* SMB2_FLUSH */ false,
 227         /* SMB2_READ */ true,
 228         /* SMB2_WRITE */ false,
 229         /* SMB2_LOCK */ false,
 230         /* SMB2_IOCTL */ true,
 231         /* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
 232         /* SMB2_ECHO */ false,
 233         /* SMB2_QUERY_DIRECTORY */ true,
 234         /* SMB2_CHANGE_NOTIFY */ true,
 235         /* SMB2_QUERY_INFO */ true,
 236         /* SMB2_SET_INFO */ false,
 237         /* SMB2_OPLOCK_BREAK */ false
 238 };
 239
 240 /*
 241  * Returns the pointer to the beginning of the data area. Length of the data
 242  * area and the offset to it (from the beginning of the smb are also returned.
 243  */
 244 char *
 245 smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
 246 {
 247         *off = 0;
 248         *len = 0;
 249
 250         /* error responses do not have data area */
 251         if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
 252             (((struct smb2_err_rsp *)hdr)->StructureSize) ==
 253                                                 SMB2_ERROR_STRUCTURE_SIZE2)
 254                 return NULL;
 255
 256         /*
 257          * Following commands have data areas so we have to get the location
 258          * of the data buffer offset and data buffer length for the particular
 259          * command.
 260          */
 261         switch (hdr->Command) {
 262         case SMB2_NEGOTIATE:
 263                 *off = le16_to_cpu(
 264                     ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferOffset);
 265                 *len = le16_to_cpu(
 266                     ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferLength);
 267                 break;
 268         case SMB2_SESSION_SETUP:
 269                 *off = le16_to_cpu(
 270                     ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferOffset);
 271                 *len = le16_to_cpu(
 272                     ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferLength);
 273                 break;
 274         case SMB2_CREATE:
 275                 *off = le32_to_cpu(
 276                     ((struct smb2_create_rsp *)hdr)->CreateContextsOffset);
 277                 *len = le32_to_cpu(
 278                     ((struct smb2_create_rsp *)hdr)->CreateContextsLength);
 279                 break;
 280         case SMB2_QUERY_INFO:
 281                 *off = le16_to_cpu(
 282                     ((struct smb2_query_info_rsp *)hdr)->OutputBufferOffset);
 283                 *len = le32_to_cpu(
 284                     ((struct smb2_query_info_rsp *)hdr)->OutputBufferLength);
 285                 break;
 286         case SMB2_READ:
 287                 *off = ((struct smb2_read_rsp *)hdr)->DataOffset;
 288                 *len = le32_to_cpu(((struct smb2_read_rsp *)hdr)->DataLength);
 289                 break;
 290         case SMB2_QUERY_DIRECTORY:
 291                 *off = le16_to_cpu(
 292                   ((struct smb2_query_directory_rsp *)hdr)->OutputBufferOffset);
 293                 *len = le32_to_cpu(
 294                   ((struct smb2_query_directory_rsp *)hdr)->OutputBufferLength);
 295                 break;
 296         case SMB2_IOCTL:
 297                 *off = le32_to_cpu(
 298                   ((struct smb2_ioctl_rsp *)hdr)->OutputOffset);
 299                 *len = le32_to_cpu(((struct smb2_ioctl_rsp *)hdr)->OutputCount);
 300                 break;
 301         case SMB2_CHANGE_NOTIFY:
 302         default:
 303                 /* BB FIXME for unimplemented cases above */
 304                 cifs_dbg(VFS, "no length check for command\n");
 305                 break;
 306         }
 307
 308         /*
 309          * Invalid length or offset probably means data area is invalid, but
 310          * we have little choice but to ignore the data area in this case.
 311          */
 312         if (*off > 4096) {
 313                 cifs_dbg(VFS, "offset %d too large, data area ignored\n", *off);
 314                 *len = 0;
 315                 *off = 0;
 316         } else if (*off < 0) {
 317                 cifs_dbg(VFS, "negative offset %d to data invalid ignore data area\n",
 318                          *off);
 319                 *off = 0;
 320                 *len = 0;
 321         } else if (*len < 0) {
 322                 cifs_dbg(VFS, "negative data length %d invalid, data area ignored\n",
 323                          *len);
 324                 *len = 0;
 325         } else if (*len > 128 * 1024) {
 326                 cifs_dbg(VFS, "data area larger than 128K: %d\n", *len);
 327                 *len = 0;
 328         }
 329
 330         /* return pointer to beginning of data area, ie offset from SMB start */
 331         if ((*off != 0) && (*len != 0))
 332                 return (char *)(&hdr->ProtocolId[0]) + *off;
 333         else
 334                 return NULL;
 335 }
 336
 337 /*
 338  * Calculate the size of the SMB message based on the fixed header
 339  * portion, the number of word parameters and the data portion of the message.
 340  */
 341 unsigned int
 342 smb2_calc_size(void *buf)
 343 {
 344         struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 345         struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
 346         int offset; /* the offset from the beginning of SMB to data area */
 347         int data_length; /* the length of the variable length data area */
 348         /* Structure Size has already been checked to make sure it is 64 */
 349         int len = 4 + le16_to_cpu(pdu->hdr.StructureSize);
 350
 351         /*
 352          * StructureSize2, ie length of fixed parameter area has already
 353          * been checked to make sure it is the correct length.
 354          */
 355         len += le16_to_cpu(pdu->StructureSize2);
 356
 357         if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
 358                 goto calc_size_exit;
 359
 360         smb2_get_data_area_len(&offset, &data_length, hdr);
 361         cifs_dbg(FYI, "SMB2 data length %d offset %d\n", data_length, offset);
 362
 363         if (data_length > 0) {
 364                 /*
 365                  * Check to make sure that data area begins after fixed area,
 366                  * Note that last byte of the fixed area is part of data area
 367                  * for some commands, typically those with odd StructureSize,
 368                  * so we must add one to the calculation (and 4 to account for
 369                  * the size of the RFC1001 hdr.
 370                  */
 371                 if (offset + 4 + 1 < len) {
 372                         cifs_dbg(VFS, "data area offset %d overlaps SMB2 header %d\n",
 373                                  offset + 4 + 1, len);
 374                         data_length = 0;
 375                 } else {
 376                         len = 4 + offset + data_length;
 377                 }
 378         }
 379 calc_size_exit:
 380         cifs_dbg(FYI, "SMB2 len %d\n", len);
 381         return len;
 382 }
 383
 384 /* Note: caller must free return buffer */
 385 __le16 *
 386 cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
 387 {
 388         int len;
 389         const char *start_of_path;
 390         __le16 *to;
 391         int map_type;
 392
 393         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SFM_CHR)
 394                 map_type = SFM_MAP_UNI_RSVD;
 395         else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
 396                 map_type = SFU_MAP_UNI_RSVD;
 397         else
 398                 map_type = NO_MAP_UNI_RSVD;
 399
 400         /* Windows doesn't allow paths beginning with \ */
 401         if (from[0] == '\\')
 402                 start_of_path = from + 1;
 403         else
 404                 start_of_path = from;
 405         to = cifs_strndup_to_utf16(start_of_path, PATH_MAX, &len,
 406                                    cifs_sb->local_nls, map_type);
 407         return to;
 408 }
 409
 410 __le32
 411 smb2_get_lease_state(struct cifsInodeInfo *cinode)
 412 {
 413         __le32 lease = 0;
 414
 415         if (CIFS_CACHE_WRITE(cinode))
 416                 lease |= SMB2_LEASE_WRITE_CACHING;
 417         if (CIFS_CACHE_HANDLE(cinode))
 418                 lease |= SMB2_LEASE_HANDLE_CACHING;
 419         if (CIFS_CACHE_READ(cinode))
 420                 lease |= SMB2_LEASE_READ_CACHING;
 421         return lease;
 422 }
 423
 424 struct smb2_lease_break_work {
 425         struct work_struct lease_break;
 426         struct tcon_link *tlink;
 427         __u8 lease_key[16];
 428         __le32 lease_state;
 429 };
 430
 431 static void
 432 cifs_ses_oplock_break(struct work_struct *work)
 433 {
 434         struct smb2_lease_break_work *lw = container_of(work,
 435                                 struct smb2_lease_break_work, lease_break);
 436         int rc;
 437
 438         rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
 439                               lw->lease_state);
 440         cifs_dbg(FYI, "Lease release rc %d\n", rc);
 441         cifs_put_tlink(lw->tlink);
 442         kfree(lw);
 443 }
 444
 445 static bool
 446 smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
 447                     struct smb2_lease_break_work *lw)
 448 {
 449         bool found;
 450         __u8 lease_state;
 451         struct list_head *tmp;
 452         struct cifsFileInfo *cfile;
 453         struct TCP_Server_Info *server = tcon->ses->server;
 454         struct cifs_pending_open *open;
 455         struct cifsInodeInfo *cinode;
 456         int ack_req = le32_to_cpu(rsp->Flags &
 457                                   SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED);
 458
 459         lease_state = le32_to_cpu(rsp->NewLeaseState);
 460
 461         list_for_each(tmp, &tcon->openFileList) {
 462                 cfile = list_entry(tmp, struct cifsFileInfo, tlist);
 463                 cinode = CIFS_I(d_inode(cfile->dentry));
 464
 465                 if (memcmp(cinode->lease_key, rsp->LeaseKey,
 466                                                         SMB2_LEASE_KEY_SIZE))
 467                         continue;
 468
 469                 cifs_dbg(FYI, "found in the open list\n");
 470                 cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
 471                          le32_to_cpu(rsp->NewLeaseState));
 472
 473                 server->ops->set_oplock_level(cinode, lease_state, 0, NULL);
 474
 475                 if (ack_req)
 476                         cfile->oplock_break_cancelled = false;
 477                 else
 478                         cfile->oplock_break_cancelled = true;
 479
 480                 queue_work(cifsiod_wq, &cfile->oplock_break);
 481                 kfree(lw);
 482                 return true;
 483         }
 484
 485         found = false;
 486         list_for_each_entry(open, &tcon->pending_opens, olist) {
 487                 if (memcmp(open->lease_key, rsp->LeaseKey,
 488                            SMB2_LEASE_KEY_SIZE))
 489                         continue;
 490
 491                 if (!found && ack_req) {
 492                         found = true;
 493                         memcpy(lw->lease_key, open->lease_key,
 494                                SMB2_LEASE_KEY_SIZE);
 495                         lw->tlink = cifs_get_tlink(open->tlink);
 496                         queue_work(cifsiod_wq, &lw->lease_break);
 497                 }
 498
 499                 cifs_dbg(FYI, "found in the pending open list\n");
 500                 cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
 501                          le32_to_cpu(rsp->NewLeaseState));
 502
 503                 open->oplock = lease_state;
 504         }
 505         return found;
 506 }
 507
 508 static bool
 509 smb2_is_valid_lease_break(char *buffer)
 510 {
 511         struct smb2_lease_break *rsp = (struct smb2_lease_break *)buffer;
 512         struct list_head *tmp, *tmp1, *tmp2;
 513         struct TCP_Server_Info *server;
 514         struct cifs_ses *ses;
 515         struct cifs_tcon *tcon;
 516         struct smb2_lease_break_work *lw;
 517
 518         lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
 519         if (!lw)
 520                 return false;
 521
 522         INIT_WORK(&lw->lease_break, cifs_ses_oplock_break);
 523         lw->lease_state = rsp->NewLeaseState;
 524
 525         cifs_dbg(FYI, "Checking for lease break\n");
 526
 527         /* look up tcon based on tid & uid */
 528         spin_lock(&cifs_tcp_ses_lock);
 529         list_for_each(tmp, &cifs_tcp_ses_list) {
 530                 server = list_entry(tmp, struct TCP_Server_Info, tcp_ses_list);
 531
 532                 list_for_each(tmp1, &server->smb_ses_list) {
 533                         ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);
 534
 535                         list_for_each(tmp2, &ses->tcon_list) {
 536                                 tcon = list_entry(tmp2, struct cifs_tcon,
 537                                                   tcon_list);
 538                                 spin_lock(&tcon->open_file_lock);
 539                                 cifs_stats_inc(
 540                                     &tcon->stats.cifs_stats.num_oplock_brks);
 541                                 if (smb2_tcon_has_lease(tcon, rsp, lw)) {
 542                                         spin_unlock(&tcon->open_file_lock);
 543                                         spin_unlock(&cifs_tcp_ses_lock);
 544                                         return true;
 545                                 }
 546                                 spin_unlock(&tcon->open_file_lock);
 547                         }
 548                 }
 549         }
 550         spin_unlock(&cifs_tcp_ses_lock);
 551         kfree(lw);
 552         cifs_dbg(FYI, "Can not process lease break - no lease matched\n");
 553         return false;
 554 }
 555
 556 bool
 557 smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 558 {
 559         struct smb2_oplock_break *rsp = (struct smb2_oplock_break *)buffer;
 560         struct list_head *tmp, *tmp1, *tmp2;
 561         struct cifs_ses *ses;
 562         struct cifs_tcon *tcon;
 563         struct cifsInodeInfo *cinode;
 564         struct cifsFileInfo *cfile;
 565
 566         cifs_dbg(FYI, "Checking for oplock break\n");
 567
 568         if (rsp->hdr.Command != SMB2_OPLOCK_BREAK)
 569                 return false;
 570
 571         if (rsp->StructureSize !=
 572                                 smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
 573                 if (le16_to_cpu(rsp->StructureSize) == 44)
 574                         return smb2_is_valid_lease_break(buffer);
 575                 else
 576                         return false;
 577         }
 578
 579         cifs_dbg(FYI, "oplock level 0x%x\n", rsp->OplockLevel);
 580
 581         /* look up tcon based on tid & uid */
 582         spin_lock(&cifs_tcp_ses_lock);
 583         list_for_each(tmp, &server->smb_ses_list) {
 584                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 585
 586                 list_for_each(tmp1, &ses->tcon_list) {
 587                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 588
 589                         spin_lock(&tcon->open_file_lock);
 590                         list_for_each(tmp2, &tcon->openFileList) {
 591                                 cfile = list_entry(tmp2, struct cifsFileInfo,
 592                                                      tlist);
 593                                 if (rsp->PersistentFid !=
 594                                     cfile->fid.persistent_fid ||
 595                                     rsp->VolatileFid !=
 596                                     cfile->fid.volatile_fid)
 597                                         continue;
 598
 599                                 cifs_dbg(FYI, "file id match, oplock break\n");
 600                                 cifs_stats_inc(
 601                                     &tcon->stats.cifs_stats.num_oplock_brks);
 602                                 cinode = CIFS_I(d_inode(cfile->dentry));
 603                                 spin_lock(&cfile->file_info_lock);
 604                                 if (!CIFS_CACHE_WRITE(cinode) &&
 605                                     rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
 606                                         cfile->oplock_break_cancelled = true;
 607                                 else
 608                                         cfile->oplock_break_cancelled = false;
 609
 610                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 611                                         &cinode->flags);
 612
 613                                 /*
 614                                  * Set flag if the server downgrades the oplock
 615                                  * to L2 else clear.
 616                                  */
 617                                 if (rsp->OplockLevel)
 618                                         set_bit(
 619                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 620                                            &cinode->flags);
 621                                 else
 622                                         clear_bit(
 623                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 624                                            &cinode->flags);
 625                                 spin_unlock(&cfile->file_info_lock);
 626                                 queue_work(cifsiod_wq, &cfile->oplock_break);
 627
 628                                 spin_unlock(&tcon->open_file_lock);
 629                                 spin_unlock(&cifs_tcp_ses_lock);
 630                                 return true;
 631                         }
 632                         spin_unlock(&tcon->open_file_lock);
 633                 }
 634         }
 635         spin_unlock(&cifs_tcp_ses_lock);
 636         cifs_dbg(FYI, "No file id matched, oplock break ignored\n");
 637         return true;
 638 }
 639
 640 void
 641 smb2_cancelled_close_fid(struct work_struct *work)
 642 {
 643         struct close_cancelled_open *cancelled = container_of(work,
 644                                         struct close_cancelled_open, work);
 645
 646         cifs_dbg(VFS, "Close unmatched open\n");
 647
 648         SMB2_close(0, cancelled->tcon, cancelled->fid.persistent_fid,
 649                    cancelled->fid.volatile_fid);
 650         cifs_put_tcon(cancelled->tcon);
 651         kfree(cancelled);
 652 }
 653
 654 int
 655 smb2_handle_cancelled_mid(char *buffer, struct TCP_Server_Info *server)
 656 {
 657         struct smb2_hdr *hdr = (struct smb2_hdr *)buffer;
 658         struct smb2_create_rsp *rsp = (struct smb2_create_rsp *)buffer;
 659         struct cifs_tcon *tcon;
 660         struct close_cancelled_open *cancelled;
 661
 662         if (hdr->Command != SMB2_CREATE || hdr->Status != STATUS_SUCCESS)
 663                 return 0;
 664
 665         cancelled = kzalloc(sizeof(*cancelled), GFP_KERNEL);
 666         if (!cancelled)
 667                 return -ENOMEM;
 668
 669         tcon = smb2_find_smb_tcon(server, hdr->SessionId, hdr->TreeId);
 670         if (!tcon) {
 671                 kfree(cancelled);
 672                 return -ENOENT;
 673         }
 674
 675         cancelled->fid.persistent_fid = rsp->PersistentFileId;
 676         cancelled->fid.volatile_fid = rsp->VolatileFileId;
 677         cancelled->tcon = tcon;
 678         INIT_WORK(&cancelled->work, smb2_cancelled_close_fid);
 679         queue_work(cifsiod_wq, &cancelled->work);
 680
 681         return 0;
 682 }