fs/cifs/misc.c

   1 /*
   2  *   fs/cifs/misc.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2008
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Lesser General Public License as published
   9  *   by the Free Software Foundation; either version 2.1 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This library is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15  *   the GNU Lesser General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Lesser General Public License
  18  *   along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/slab.h>
  23 #include <linux/ctype.h>
  24 #include <linux/mempool.h>
  25 #include <linux/vmalloc.h>
  26 #include "cifspdu.h"
  27 #include "cifsglob.h"
  28 #include "cifsproto.h"
  29 #include "cifs_debug.h"
  30 #include "smberr.h"
  31 #include "nterr.h"
  32 #include "cifs_unicode.h"
  33 #include "smb2pdu.h"
  34 #include "cifsfs.h"
  35 #ifdef CONFIG_CIFS_DFS_UPCALL
  36 #include "dns_resolve.h"
  37 #endif
  38
  39 extern mempool_t *cifs_sm_req_poolp;
  40 extern mempool_t *cifs_req_poolp;
  41
  42 /* The xid serves as a useful identifier for each incoming vfs request,
  43    in a similar way to the mid which is useful to track each sent smb,
  44    and CurrentXid can also provide a running counter (although it
  45    will eventually wrap past zero) of the total vfs operations handled
  46    since the cifs fs was mounted */
  47
  48 unsigned int
  49 _get_xid(void)
  50 {
  51         unsigned int xid;
  52
  53         spin_lock(&GlobalMid_Lock);
  54         GlobalTotalActiveXid++;
  55
  56         /* keep high water mark for number of simultaneous ops in filesystem */
  57         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  58                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  59         if (GlobalTotalActiveXid > 65000)
  60                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  61         xid = GlobalCurrentXid++;
  62         spin_unlock(&GlobalMid_Lock);
  63         return xid;
  64 }
  65
  66 void
  67 _free_xid(unsigned int xid)
  68 {
  69         spin_lock(&GlobalMid_Lock);
  70         /* if (GlobalTotalActiveXid == 0)
  71                 BUG(); */
  72         GlobalTotalActiveXid--;
  73         spin_unlock(&GlobalMid_Lock);
  74 }
  75
  76 struct cifs_ses *
  77 sesInfoAlloc(void)
  78 {
  79         struct cifs_ses *ret_buf;
  80
  81         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  82         if (ret_buf) {
  83                 atomic_inc(&sesInfoAllocCount);
  84                 ret_buf->status = CifsNew;
  85                 ++ret_buf->ses_count;
  86                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  87                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  88                 mutex_init(&ret_buf->session_mutex);
  89                 spin_lock_init(&ret_buf->iface_lock);
  90         }
  91         return ret_buf;
  92 }
  93
  94 void
  95 sesInfoFree(struct cifs_ses *buf_to_free)
  96 {
  97         if (buf_to_free == NULL) {
  98                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  99                 return;
 100         }
 101
 102         atomic_dec(&sesInfoAllocCount);
 103         kfree(buf_to_free->serverOS);
 104         kfree(buf_to_free->serverDomain);
 105         kfree(buf_to_free->serverNOS);
 106         kfree_sensitive(buf_to_free->password);
 107         kfree(buf_to_free->user_name);
 108         kfree(buf_to_free->domainName);
 109         kfree_sensitive(buf_to_free->auth_key.response);
 110         kfree(buf_to_free->iface_list);
 111         kfree_sensitive(buf_to_free);
 112 }
 113
 114 struct cifs_tcon *
 115 tconInfoAlloc(void)
 116 {
 117         struct cifs_tcon *ret_buf;
 118
 119         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 120         if (!ret_buf)
 121                 return NULL;
 122         ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), GFP_KERNEL);
 123         if (!ret_buf->crfid.fid) {
 124                 kfree(ret_buf);
 125                 return NULL;
 126         }
 127
 128         atomic_inc(&tconInfoAllocCount);
 129         ret_buf->tidStatus = CifsNew;
 130         ++ret_buf->tc_count;
 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         mutex_init(&ret_buf->crfid.fid_mutex);
 135         spin_lock_init(&ret_buf->stat_lock);
 136         atomic_set(&ret_buf->num_local_opens, 0);
 137         atomic_set(&ret_buf->num_remote_opens, 0);
 138
 139         return ret_buf;
 140 }
 141
 142 void
 143 tconInfoFree(struct cifs_tcon *buf_to_free)
 144 {
 145         if (buf_to_free == NULL) {
 146                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 147                 return;
 148         }
 149         atomic_dec(&tconInfoAllocCount);
 150         kfree(buf_to_free->nativeFileSystem);
 151         kfree_sensitive(buf_to_free->password);
 152         kfree(buf_to_free->crfid.fid);
 153 #ifdef CONFIG_CIFS_DFS_UPCALL
 154         kfree(buf_to_free->dfs_path);
 155 #endif
 156         kfree(buf_to_free);
 157 }
 158
 159 struct smb_hdr *
 160 cifs_buf_get(void)
 161 {
 162         struct smb_hdr *ret_buf = NULL;
 163         /*
 164          * SMB2 header is bigger than CIFS one - no problems to clean some
 165          * more bytes for CIFS.
 166          */
 167         size_t buf_size = sizeof(struct smb2_sync_hdr);
 168
 169         /*
 170          * We could use negotiated size instead of max_msgsize -
 171          * but it may be more efficient to always alloc same size
 172          * albeit slightly larger than necessary and maxbuffersize
 173          * defaults to this and can not be bigger.
 174          */
 175         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 176
 177         /* clear the first few header bytes */
 178         /* for most paths, more is cleared in header_assemble */
 179         memset(ret_buf, 0, buf_size + 3);
 180         atomic_inc(&bufAllocCount);
 181 #ifdef CONFIG_CIFS_STATS2
 182         atomic_inc(&totBufAllocCount);
 183 #endif /* CONFIG_CIFS_STATS2 */
 184
 185         return ret_buf;
 186 }
 187
 188 void
 189 cifs_buf_release(void *buf_to_free)
 190 {
 191         if (buf_to_free == NULL) {
 192                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 193                 return;
 194         }
 195         mempool_free(buf_to_free, cifs_req_poolp);
 196
 197         atomic_dec(&bufAllocCount);
 198         return;
 199 }
 200
 201 struct smb_hdr *
 202 cifs_small_buf_get(void)
 203 {
 204         struct smb_hdr *ret_buf = NULL;
 205
 206 /* We could use negotiated size instead of max_msgsize -
 207    but it may be more efficient to always alloc same size
 208    albeit slightly larger than necessary and maxbuffersize
 209    defaults to this and can not be bigger */
 210         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 211         /* No need to clear memory here, cleared in header assemble */
 212         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 213         atomic_inc(&smBufAllocCount);
 214 #ifdef CONFIG_CIFS_STATS2
 215         atomic_inc(&totSmBufAllocCount);
 216 #endif /* CONFIG_CIFS_STATS2 */
 217
 218         return ret_buf;
 219 }
 220
 221 void
 222 cifs_small_buf_release(void *buf_to_free)
 223 {
 224
 225         if (buf_to_free == NULL) {
 226                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 227                 return;
 228         }
 229         mempool_free(buf_to_free, cifs_sm_req_poolp);
 230
 231         atomic_dec(&smBufAllocCount);
 232         return;
 233 }
 234
 235 void
 236 free_rsp_buf(int resp_buftype, void *rsp)
 237 {
 238         if (resp_buftype == CIFS_SMALL_BUFFER)
 239                 cifs_small_buf_release(rsp);
 240         else if (resp_buftype == CIFS_LARGE_BUFFER)
 241                 cifs_buf_release(rsp);
 242 }
 243
 244 /* NB: MID can not be set if treeCon not passed in, in that
 245    case it is responsbility of caller to set the mid */
 246 void
 247 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 248                 const struct cifs_tcon *treeCon, int word_count
 249                 /* length of fixed section (word count) in two byte units  */)
 250 {
 251         char *temp = (char *) buffer;
 252
 253         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 254
 255         buffer->smb_buf_length = cpu_to_be32(
 256             (2 * word_count) + sizeof(struct smb_hdr) -
 257             4 /*  RFC 1001 length field does not count */  +
 258             2 /* for bcc field itself */) ;
 259
 260         buffer->Protocol[0] = 0xFF;
 261         buffer->Protocol[1] = 'S';
 262         buffer->Protocol[2] = 'M';
 263         buffer->Protocol[3] = 'B';
 264         buffer->Command = smb_command;
 265         buffer->Flags = 0x00;   /* case sensitive */
 266         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 267         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 268         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 269         if (treeCon) {
 270                 buffer->Tid = treeCon->tid;
 271                 if (treeCon->ses) {
 272                         if (treeCon->ses->capabilities & CAP_UNICODE)
 273                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 274                         if (treeCon->ses->capabilities & CAP_STATUS32)
 275                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 276
 277                         /* Uid is not converted */
 278                         buffer->Uid = treeCon->ses->Suid;
 279                         buffer->Mid = get_next_mid(treeCon->ses->server);
 280                 }
 281                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 282                         buffer->Flags2 |= SMBFLG2_DFS;
 283                 if (treeCon->nocase)
 284                         buffer->Flags  |= SMBFLG_CASELESS;
 285                 if ((treeCon->ses) && (treeCon->ses->server))
 286                         if (treeCon->ses->server->sign)
 287                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 288         }
 289
 290 /*  endian conversion of flags is now done just before sending */
 291         buffer->WordCount = (char) word_count;
 292         return;
 293 }
 294
 295 static int
 296 check_smb_hdr(struct smb_hdr *smb)
 297 {
 298         /* does it have the right SMB "signature" ? */
 299         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 300                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 301                          *(unsigned int *)smb->Protocol);
 302                 return 1;
 303         }
 304
 305         /* if it's a response then accept */
 306         if (smb->Flags & SMBFLG_RESPONSE)
 307                 return 0;
 308
 309         /* only one valid case where server sends us request */
 310         if (smb->Command == SMB_COM_LOCKING_ANDX)
 311                 return 0;
 312
 313         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 314                  get_mid(smb));
 315         return 1;
 316 }
 317
 318 int
 319 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 320 {
 321         struct smb_hdr *smb = (struct smb_hdr *)buf;
 322         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 323         __u32 clc_len;  /* calculated length */
 324         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 325                  total_read, rfclen);
 326
 327         /* is this frame too small to even get to a BCC? */
 328         if (total_read < 2 + sizeof(struct smb_hdr)) {
 329                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 330                             && (smb->Status.CifsError != 0)) {
 331                         /* it's an error return */
 332                         smb->WordCount = 0;
 333                         /* some error cases do not return wct and bcc */
 334                         return 0;
 335                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 336                                 (smb->WordCount == 0)) {
 337                         char *tmp = (char *)smb;
 338                         /* Need to work around a bug in two servers here */
 339                         /* First, check if the part of bcc they sent was zero */
 340                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 341                                 /* some servers return only half of bcc
 342                                  * on simple responses (wct, bcc both zero)
 343                                  * in particular have seen this on
 344                                  * ulogoffX and FindClose. This leaves
 345                                  * one byte of bcc potentially unitialized
 346                                  */
 347                                 /* zero rest of bcc */
 348                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 349                                 return 0;
 350                         }
 351                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 352                 } else {
 353                         cifs_dbg(VFS, "Length less than smb header size\n");
 354                 }
 355                 return -EIO;
 356         } else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
 357                 cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
 358                          __func__, smb->WordCount);
 359                 return -EIO;
 360         }
 361
 362         /* otherwise, there is enough to get to the BCC */
 363         if (check_smb_hdr(smb))
 364                 return -EIO;
 365         clc_len = smbCalcSize(smb, server);
 366
 367         if (4 + rfclen != total_read) {
 368                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 369                          rfclen);
 370                 return -EIO;
 371         }
 372
 373         if (4 + rfclen != clc_len) {
 374                 __u16 mid = get_mid(smb);
 375                 /* check if bcc wrapped around for large read responses */
 376                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 377                         /* check if lengths match mod 64K */
 378                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 379                                 return 0; /* bcc wrapped */
 380                 }
 381                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 382                          clc_len, 4 + rfclen, mid);
 383
 384                 if (4 + rfclen < clc_len) {
 385                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 386                                  rfclen, mid);
 387                         return -EIO;
 388                 } else if (rfclen > clc_len + 512) {
 389                         /*
 390                          * Some servers (Windows XP in particular) send more
 391                          * data than the lengths in the SMB packet would
 392                          * indicate on certain calls (byte range locks and
 393                          * trans2 find first calls in particular). While the
 394                          * client can handle such a frame by ignoring the
 395                          * trailing data, we choose limit the amount of extra
 396                          * data to 512 bytes.
 397                          */
 398                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 399                                  rfclen, mid);
 400                         return -EIO;
 401                 }
 402         }
 403         return 0;
 404 }
 405
 406 bool
 407 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 408 {
 409         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 410         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 411         struct list_head *tmp, *tmp1, *tmp2;
 412         struct cifs_ses *ses;
 413         struct cifs_tcon *tcon;
 414         struct cifsInodeInfo *pCifsInode;
 415         struct cifsFileInfo *netfile;
 416
 417         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 418         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 419            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 420                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 421                         (struct smb_com_transaction_change_notify_rsp *)buf;
 422                 struct file_notify_information *pnotify;
 423                 __u32 data_offset = 0;
 424                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 425
 426                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 427                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 428
 429                         if (data_offset >
 430                             len - sizeof(struct file_notify_information)) {
 431                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
 432                                          data_offset);
 433                                 return true;
 434                         }
 435                         pnotify = (struct file_notify_information *)
 436                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 437                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 438                                  pnotify->FileName, pnotify->Action);
 439                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 440                                 sizeof(struct smb_hdr)+60); */
 441                         return true;
 442                 }
 443                 if (pSMBr->hdr.Status.CifsError) {
 444                         cifs_dbg(FYI, "notify err 0x%x\n",
 445                                  pSMBr->hdr.Status.CifsError);
 446                         return true;
 447                 }
 448                 return false;
 449         }
 450         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 451                 return false;
 452         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 453                 /* no sense logging error on invalid handle on oplock
 454                    break - harmless race between close request and oplock
 455                    break response is expected from time to time writing out
 456                    large dirty files cached on the client */
 457                 if ((NT_STATUS_INVALID_HANDLE) ==
 458                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 459                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
 460                         return true;
 461                 } else if (ERRbadfid ==
 462                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 463                         return true;
 464                 } else {
 465                         return false; /* on valid oplock brk we get "request" */
 466                 }
 467         }
 468         if (pSMB->hdr.WordCount != 8)
 469                 return false;
 470
 471         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 472                  pSMB->LockType, pSMB->OplockLevel);
 473         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 474                 return false;
 475
 476         /* look up tcon based on tid & uid */
 477         spin_lock(&cifs_tcp_ses_lock);
 478         list_for_each(tmp, &srv->smb_ses_list) {
 479                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 480                 list_for_each(tmp1, &ses->tcon_list) {
 481                         tcon = list_entry(tmp1, struct cifs_tcon, 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(tmp2, &tcon->openFileList) {
 488                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 489                                                      tlist);
 490                                 if (pSMB->Fid != netfile->fid.netfid)
 491                                         continue;
 492
 493                                 cifs_dbg(FYI, "file id match, oplock break\n");
 494                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 495
 496                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 497                                         &pCifsInode->flags);
 498
 499                                 netfile->oplock_epoch = 0;
 500                                 netfile->oplock_level = pSMB->OplockLevel;
 501                                 netfile->oplock_break_cancelled = false;
 502                                 cifs_queue_oplock_break(netfile);
 503
 504                                 spin_unlock(&tcon->open_file_lock);
 505                                 spin_unlock(&cifs_tcp_ses_lock);
 506                                 return true;
 507                         }
 508                         spin_unlock(&tcon->open_file_lock);
 509                         spin_unlock(&cifs_tcp_ses_lock);
 510                         cifs_dbg(FYI, "No matching file for oplock break\n");
 511                         return true;
 512                 }
 513         }
 514         spin_unlock(&cifs_tcp_ses_lock);
 515         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 516         return true;
 517 }
 518
 519 void
 520 dump_smb(void *buf, int smb_buf_length)
 521 {
 522         if (traceSMB == 0)
 523                 return;
 524
 525         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 526                        smb_buf_length, true);
 527 }
 528
 529 void
 530 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 531 {
 532         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 533                 struct cifs_tcon *tcon = NULL;
 534
 535                 if (cifs_sb->master_tlink)
 536                         tcon = cifs_sb_master_tcon(cifs_sb);
 537
 538                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 539                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
 540                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 541                          tcon ? tcon->treeName : "new server");
 542                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 543                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 544
 545         }
 546 }
 547
 548 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 549 {
 550         oplock &= 0xF;
 551
 552         if (oplock == OPLOCK_EXCLUSIVE) {
 553                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 554                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 555                          &cinode->vfs_inode);
 556         } else if (oplock == OPLOCK_READ) {
 557                 cinode->oplock = CIFS_CACHE_READ_FLG;
 558                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 559                          &cinode->vfs_inode);
 560         } else
 561                 cinode->oplock = 0;
 562 }
 563
 564 /*
 565  * We wait for oplock breaks to be processed before we attempt to perform
 566  * writes.
 567  */
 568 int cifs_get_writer(struct cifsInodeInfo *cinode)
 569 {
 570         int rc;
 571
 572 start:
 573         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 574                          TASK_KILLABLE);
 575         if (rc)
 576                 return rc;
 577
 578         spin_lock(&cinode->writers_lock);
 579         if (!cinode->writers)
 580                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 581         cinode->writers++;
 582         /* Check to see if we have started servicing an oplock break */
 583         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 584                 cinode->writers--;
 585                 if (cinode->writers == 0) {
 586                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 587                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 588                 }
 589                 spin_unlock(&cinode->writers_lock);
 590                 goto start;
 591         }
 592         spin_unlock(&cinode->writers_lock);
 593         return 0;
 594 }
 595
 596 void cifs_put_writer(struct cifsInodeInfo *cinode)
 597 {
 598         spin_lock(&cinode->writers_lock);
 599         cinode->writers--;
 600         if (cinode->writers == 0) {
 601                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 602                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 603         }
 604         spin_unlock(&cinode->writers_lock);
 605 }
 606
 607 /**
 608  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 609  *
 610  * This function is called from the demultiplex thread when it
 611  * receives an oplock break for @cfile.
 612  *
 613  * Assumes the tcon->open_file_lock is held.
 614  * Assumes cfile->file_info_lock is NOT held.
 615  */
 616 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 617 {
 618         /*
 619          * Bump the handle refcount now while we hold the
 620          * open_file_lock to enforce the validity of it for the oplock
 621          * break handler. The matching put is done at the end of the
 622          * handler.
 623          */
 624         cifsFileInfo_get(cfile);
 625
 626         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 627 }
 628
 629 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 630 {
 631         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 632         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 633 }
 634
 635 bool
 636 backup_cred(struct cifs_sb_info *cifs_sb)
 637 {
 638         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 639                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
 640                         return true;
 641         }
 642         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 643                 if (in_group_p(cifs_sb->mnt_backupgid))
 644                         return true;
 645         }
 646
 647         return false;
 648 }
 649
 650 void
 651 cifs_del_pending_open(struct cifs_pending_open *open)
 652 {
 653         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 654         list_del(&open->olist);
 655         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 656 }
 657
 658 void
 659 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 660                              struct cifs_pending_open *open)
 661 {
 662         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 663         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 664         open->tlink = tlink;
 665         fid->pending_open = open;
 666         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 667 }
 668
 669 void
 670 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 671                       struct cifs_pending_open *open)
 672 {
 673         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 674         cifs_add_pending_open_locked(fid, tlink, open);
 675         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 676 }
 677
 678 /* parses DFS refferal V3 structure
 679  * caller is responsible for freeing target_nodes
 680  * returns:
 681  * - on success - 0
 682  * - on failure - errno
 683  */
 684 int
 685 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 686                     unsigned int *num_of_nodes,
 687                     struct dfs_info3_param **target_nodes,
 688                     const struct nls_table *nls_codepage, int remap,
 689                     const char *searchName, bool is_unicode)
 690 {
 691         int i, rc = 0;
 692         char *data_end;
 693         struct dfs_referral_level_3 *ref;
 694
 695         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 696
 697         if (*num_of_nodes < 1) {
 698                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 699                          *num_of_nodes);
 700                 rc = -EINVAL;
 701                 goto parse_DFS_referrals_exit;
 702         }
 703
 704         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 705         if (ref->VersionNumber != cpu_to_le16(3)) {
 706                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 707                          le16_to_cpu(ref->VersionNumber));
 708                 rc = -EINVAL;
 709                 goto parse_DFS_referrals_exit;
 710         }
 711
 712         /* get the upper boundary of the resp buffer */
 713         data_end = (char *)rsp + rsp_size;
 714
 715         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 716                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 717
 718         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 719                                 GFP_KERNEL);
 720         if (*target_nodes == NULL) {
 721                 rc = -ENOMEM;
 722                 goto parse_DFS_referrals_exit;
 723         }
 724
 725         /* collect necessary data from referrals */
 726         for (i = 0; i < *num_of_nodes; i++) {
 727                 char *temp;
 728                 int max_len;
 729                 struct dfs_info3_param *node = (*target_nodes)+i;
 730
 731                 node->flags = le32_to_cpu(rsp->DFSFlags);
 732                 if (is_unicode) {
 733                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 734                                                 GFP_KERNEL);
 735                         if (tmp == NULL) {
 736                                 rc = -ENOMEM;
 737                                 goto parse_DFS_referrals_exit;
 738                         }
 739                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 740                                            PATH_MAX, nls_codepage, remap);
 741                         node->path_consumed = cifs_utf16_bytes(tmp,
 742                                         le16_to_cpu(rsp->PathConsumed),
 743                                         nls_codepage);
 744                         kfree(tmp);
 745                 } else
 746                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 747
 748                 node->server_type = le16_to_cpu(ref->ServerType);
 749                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 750
 751                 /* copy DfsPath */
 752                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 753                 max_len = data_end - temp;
 754                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 755                                                 is_unicode, nls_codepage);
 756                 if (!node->path_name) {
 757                         rc = -ENOMEM;
 758                         goto parse_DFS_referrals_exit;
 759                 }
 760
 761                 /* copy link target UNC */
 762                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 763                 max_len = data_end - temp;
 764                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 765                                                 is_unicode, nls_codepage);
 766                 if (!node->node_name) {
 767                         rc = -ENOMEM;
 768                         goto parse_DFS_referrals_exit;
 769                 }
 770
 771                 node->ttl = le32_to_cpu(ref->TimeToLive);
 772
 773                 ref++;
 774         }
 775
 776 parse_DFS_referrals_exit:
 777         if (rc) {
 778                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 779                 *target_nodes = NULL;
 780                 *num_of_nodes = 0;
 781         }
 782         return rc;
 783 }
 784
 785 struct cifs_aio_ctx *
 786 cifs_aio_ctx_alloc(void)
 787 {
 788         struct cifs_aio_ctx *ctx;
 789
 790         /*
 791          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
 792          * to false so that we know when we have to unreference pages within
 793          * cifs_aio_ctx_release()
 794          */
 795         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
 796         if (!ctx)
 797                 return NULL;
 798
 799         INIT_LIST_HEAD(&ctx->list);
 800         mutex_init(&ctx->aio_mutex);
 801         init_completion(&ctx->done);
 802         kref_init(&ctx->refcount);
 803         return ctx;
 804 }
 805
 806 void
 807 cifs_aio_ctx_release(struct kref *refcount)
 808 {
 809         struct cifs_aio_ctx *ctx = container_of(refcount,
 810                                         struct cifs_aio_ctx, refcount);
 811
 812         cifsFileInfo_put(ctx->cfile);
 813
 814         /*
 815          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
 816          * which means that iov_iter_get_pages() was a success and thus that
 817          * we have taken reference on pages.
 818          */
 819         if (ctx->bv) {
 820                 unsigned i;
 821
 822                 for (i = 0; i < ctx->npages; i++) {
 823                         if (ctx->should_dirty)
 824                                 set_page_dirty(ctx->bv[i].bv_page);
 825                         put_page(ctx->bv[i].bv_page);
 826                 }
 827                 kvfree(ctx->bv);
 828         }
 829
 830         kfree(ctx);
 831 }
 832
 833 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
 834
 835 int
 836 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 837 {
 838         ssize_t rc;
 839         unsigned int cur_npages;
 840         unsigned int npages = 0;
 841         unsigned int i;
 842         size_t len;
 843         size_t count = iov_iter_count(iter);
 844         unsigned int saved_len;
 845         size_t start;
 846         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
 847         struct page **pages = NULL;
 848         struct bio_vec *bv = NULL;
 849
 850         if (iov_iter_is_kvec(iter)) {
 851                 memcpy(&ctx->iter, iter, sizeof(*iter));
 852                 ctx->len = count;
 853                 iov_iter_advance(iter, count);
 854                 return 0;
 855         }
 856
 857         if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
 858                 bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
 859
 860         if (!bv) {
 861                 bv = vmalloc(array_size(max_pages, sizeof(*bv)));
 862                 if (!bv)
 863                         return -ENOMEM;
 864         }
 865
 866         if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
 867                 pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
 868
 869         if (!pages) {
 870                 pages = vmalloc(array_size(max_pages, sizeof(*pages)));
 871                 if (!pages) {
 872                         kvfree(bv);
 873                         return -ENOMEM;
 874                 }
 875         }
 876
 877         saved_len = count;
 878
 879         while (count && npages < max_pages) {
 880                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
 881                 if (rc < 0) {
 882                         cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc);
 883                         break;
 884                 }
 885
 886                 if (rc > count) {
 887                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
 888                                  count);
 889                         break;
 890                 }
 891
 892                 iov_iter_advance(iter, rc);
 893                 count -= rc;
 894                 rc += start;
 895                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
 896
 897                 if (npages + cur_npages > max_pages) {
 898                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
 899                                  npages + cur_npages, max_pages);
 900                         break;
 901                 }
 902
 903                 for (i = 0; i < cur_npages; i++) {
 904                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
 905                         bv[npages + i].bv_page = pages[i];
 906                         bv[npages + i].bv_offset = start;
 907                         bv[npages + i].bv_len = len - start;
 908                         rc -= len;
 909                         start = 0;
 910                 }
 911
 912                 npages += cur_npages;
 913         }
 914
 915         kvfree(pages);
 916         ctx->bv = bv;
 917         ctx->len = saved_len - count;
 918         ctx->npages = npages;
 919         iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
 920         return 0;
 921 }
 922
 923 /**
 924  * cifs_alloc_hash - allocate hash and hash context together
 925  *
 926  * The caller has to make sure @sdesc is initialized to either NULL or
 927  * a valid context. Both can be freed via cifs_free_hash().
 928  */
 929 int
 930 cifs_alloc_hash(const char *name,
 931                 struct crypto_shash **shash, struct sdesc **sdesc)
 932 {
 933         int rc = 0;
 934         size_t size;
 935
 936         if (*sdesc != NULL)
 937                 return 0;
 938
 939         *shash = crypto_alloc_shash(name, 0, 0);
 940         if (IS_ERR(*shash)) {
 941                 cifs_dbg(VFS, "Could not allocate crypto %s\n", name);
 942                 rc = PTR_ERR(*shash);
 943                 *shash = NULL;
 944                 *sdesc = NULL;
 945                 return rc;
 946         }
 947
 948         size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
 949         *sdesc = kmalloc(size, GFP_KERNEL);
 950         if (*sdesc == NULL) {
 951                 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
 952                 crypto_free_shash(*shash);
 953                 *shash = NULL;
 954                 return -ENOMEM;
 955         }
 956
 957         (*sdesc)->shash.tfm = *shash;
 958         return 0;
 959 }
 960
 961 /**
 962  * cifs_free_hash - free hash and hash context together
 963  *
 964  * Freeing a NULL hash or context is safe.
 965  */
 966 void
 967 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
 968 {
 969         kfree(*sdesc);
 970         *sdesc = NULL;
 971         if (*shash)
 972                 crypto_free_shash(*shash);
 973         *shash = NULL;
 974 }
 975
 976 /**
 977  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
 978  * Input: rqst - a smb_rqst, page - a page index for rqst
 979  * Output: *len - the length for this page, *offset - the offset for this page
 980  */
 981 void rqst_page_get_length(const struct smb_rqst *rqst, unsigned int page,
 982                           unsigned int *len, unsigned int *offset)
 983 {
 984         *len = rqst->rq_pagesz;
 985         *offset = (page == 0) ? rqst->rq_offset : 0;
 986
 987         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
 988                 *len = rqst->rq_tailsz;
 989         else if (page == 0)
 990                 *len = rqst->rq_pagesz - rqst->rq_offset;
 991 }
 992
 993 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
 994 {
 995         const char *end;
 996
 997         /* skip initial slashes */
 998         while (*unc && (*unc == '\\' || *unc == '/'))
 999                 unc++;
1000
1001         end = unc;
1002
1003         while (*end && !(*end == '\\' || *end == '/'))
1004                 end++;
1005
1006         *h = unc;
1007         *len = end - unc;
1008 }
1009
1010 /**
1011  * copy_path_name - copy src path to dst, possibly truncating
1012  *
1013  * returns number of bytes written (including trailing nul)
1014  */
1015 int copy_path_name(char *dst, const char *src)
1016 {
1017         int name_len;
1018
1019         /*
1020          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1021          * will truncate and strlen(dst) will be PATH_MAX-1
1022          */
1023         name_len = strscpy(dst, src, PATH_MAX);
1024         if (WARN_ON_ONCE(name_len < 0))
1025                 name_len = PATH_MAX-1;
1026
1027         /* we count the trailing nul */
1028         name_len++;
1029         return name_len;
1030 }
1031
1032 struct super_cb_data {
1033         void *data;
1034         struct super_block *sb;
1035 };
1036
1037 static void tcp_super_cb(struct super_block *sb, void *arg)
1038 {
1039         struct super_cb_data *sd = arg;
1040         struct TCP_Server_Info *server = sd->data;
1041         struct cifs_sb_info *cifs_sb;
1042         struct cifs_tcon *tcon;
1043
1044         if (sd->sb)
1045                 return;
1046
1047         cifs_sb = CIFS_SB(sb);
1048         tcon = cifs_sb_master_tcon(cifs_sb);
1049         if (tcon->ses->server == server)
1050                 sd->sb = sb;
1051 }
1052
1053 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1054                                             void *data)
1055 {
1056         struct super_cb_data sd = {
1057                 .data = data,
1058                 .sb = NULL,
1059         };
1060         struct file_system_type **fs_type = (struct file_system_type *[]) {
1061                 &cifs_fs_type, &smb3_fs_type, NULL,
1062         };
1063
1064         for (; *fs_type; fs_type++) {
1065                 iterate_supers_type(*fs_type, f, &sd);
1066                 if (sd.sb) {
1067                         /*
1068                          * Grab an active reference in order to prevent automounts (DFS links)
1069                          * of expiring and then freeing up our cifs superblock pointer while
1070                          * we're doing failover.
1071                          */
1072                         cifs_sb_active(sd.sb);
1073                         return sd.sb;
1074                 }
1075         }
1076         return ERR_PTR(-EINVAL);
1077 }
1078
1079 static void __cifs_put_super(struct super_block *sb)
1080 {
1081         if (!IS_ERR_OR_NULL(sb))
1082                 cifs_sb_deactive(sb);
1083 }
1084
1085 struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server)
1086 {
1087         return __cifs_get_super(tcp_super_cb, server);
1088 }
1089
1090 void cifs_put_tcp_super(struct super_block *sb)
1091 {
1092         __cifs_put_super(sb);
1093 }
1094
1095 #ifdef CONFIG_CIFS_DFS_UPCALL
1096 int match_target_ip(struct TCP_Server_Info *server,
1097                     const char *share, size_t share_len,
1098                     bool *result)
1099 {
1100         int rc;
1101         char *target, *tip = NULL;
1102         struct sockaddr tipaddr;
1103
1104         *result = false;
1105
1106         target = kzalloc(share_len + 3, GFP_KERNEL);
1107         if (!target) {
1108                 rc = -ENOMEM;
1109                 goto out;
1110         }
1111
1112         scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1113
1114         cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1115
1116         rc = dns_resolve_server_name_to_ip(target, &tip);
1117         if (rc < 0)
1118                 goto out;
1119
1120         cifs_dbg(FYI, "%s: target ip: %s\n", __func__, tip);
1121
1122         if (!cifs_convert_address(&tipaddr, tip, strlen(tip))) {
1123                 cifs_dbg(VFS, "%s: failed to convert target ip address\n",
1124                          __func__);
1125                 rc = -EINVAL;
1126                 goto out;
1127         }
1128
1129         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr,
1130                                     &tipaddr);
1131         cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1132         rc = 0;
1133
1134 out:
1135         kfree(target);
1136         kfree(tip);
1137
1138         return rc;
1139 }
1140
1141 static void tcon_super_cb(struct super_block *sb, void *arg)
1142 {
1143         struct super_cb_data *sd = arg;
1144         struct cifs_tcon *tcon = sd->data;
1145         struct cifs_sb_info *cifs_sb;
1146
1147         if (sd->sb)
1148                 return;
1149
1150         cifs_sb = CIFS_SB(sb);
1151         if (tcon->dfs_path && cifs_sb->origin_fullpath &&
1152             !strcasecmp(tcon->dfs_path, cifs_sb->origin_fullpath))
1153                 sd->sb = sb;
1154 }
1155
1156 static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
1157 {
1158         return __cifs_get_super(tcon_super_cb, tcon);
1159 }
1160
1161 static inline void cifs_put_tcon_super(struct super_block *sb)
1162 {
1163         __cifs_put_super(sb);
1164 }
1165 #else
1166 static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
1167 {
1168         return ERR_PTR(-EOPNOTSUPP);
1169 }
1170
1171 static inline void cifs_put_tcon_super(struct super_block *sb)
1172 {
1173 }
1174 #endif
1175
1176 int update_super_prepath(struct cifs_tcon *tcon, char *prefix)
1177 {
1178         struct super_block *sb;
1179         struct cifs_sb_info *cifs_sb;
1180         int rc = 0;
1181
1182         sb = cifs_get_tcon_super(tcon);
1183         if (IS_ERR(sb))
1184                 return PTR_ERR(sb);
1185
1186         cifs_sb = CIFS_SB(sb);
1187
1188         kfree(cifs_sb->prepath);
1189
1190         if (prefix && *prefix) {
1191                 cifs_sb->prepath = kstrndup(prefix, strlen(prefix), GFP_ATOMIC);
1192                 if (!cifs_sb->prepath) {
1193                         rc = -ENOMEM;
1194                         goto out;
1195                 }
1196
1197                 convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1198         } else
1199                 cifs_sb->prepath = NULL;
1200
1201         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1202
1203 out:
1204         cifs_put_tcon_super(sb);
1205         return rc;
1206 }