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TOMOYO Linux Cross Reference
Linux/fs/cifs/misc.c

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  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 
 35 extern mempool_t *cifs_sm_req_poolp;
 36 extern mempool_t *cifs_req_poolp;
 37 
 38 /* The xid serves as a useful identifier for each incoming vfs request,
 39    in a similar way to the mid which is useful to track each sent smb,
 40    and CurrentXid can also provide a running counter (although it
 41    will eventually wrap past zero) of the total vfs operations handled
 42    since the cifs fs was mounted */
 43 
 44 unsigned int
 45 _get_xid(void)
 46 {
 47         unsigned int xid;
 48 
 49         spin_lock(&GlobalMid_Lock);
 50         GlobalTotalActiveXid++;
 51 
 52         /* keep high water mark for number of simultaneous ops in filesystem */
 53         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
 54                 GlobalMaxActiveXid = GlobalTotalActiveXid;
 55         if (GlobalTotalActiveXid > 65000)
 56                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
 57         xid = GlobalCurrentXid++;
 58         spin_unlock(&GlobalMid_Lock);
 59         return xid;
 60 }
 61 
 62 void
 63 _free_xid(unsigned int xid)
 64 {
 65         spin_lock(&GlobalMid_Lock);
 66         /* if (GlobalTotalActiveXid == 0)
 67                 BUG(); */
 68         GlobalTotalActiveXid--;
 69         spin_unlock(&GlobalMid_Lock);
 70 }
 71 
 72 struct cifs_ses *
 73 sesInfoAlloc(void)
 74 {
 75         struct cifs_ses *ret_buf;
 76 
 77         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
 78         if (ret_buf) {
 79                 atomic_inc(&sesInfoAllocCount);
 80                 ret_buf->status = CifsNew;
 81                 ++ret_buf->ses_count;
 82                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
 83                 INIT_LIST_HEAD(&ret_buf->tcon_list);
 84                 mutex_init(&ret_buf->session_mutex);
 85                 spin_lock_init(&ret_buf->iface_lock);
 86         }
 87         return ret_buf;
 88 }
 89 
 90 void
 91 sesInfoFree(struct cifs_ses *buf_to_free)
 92 {
 93         if (buf_to_free == NULL) {
 94                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
 95                 return;
 96         }
 97 
 98         atomic_dec(&sesInfoAllocCount);
 99         kfree(buf_to_free->serverOS);
100         kfree(buf_to_free->serverDomain);
101         kfree(buf_to_free->serverNOS);
102         kzfree(buf_to_free->password);
103         kfree(buf_to_free->user_name);
104         kfree(buf_to_free->domainName);
105         kzfree(buf_to_free->auth_key.response);
106         kfree(buf_to_free->iface_list);
107         kzfree(buf_to_free);
108 }
109 
110 struct cifs_tcon *
111 tconInfoAlloc(void)
112 {
113         struct cifs_tcon *ret_buf;
114         ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
115         if (ret_buf) {
116                 atomic_inc(&tconInfoAllocCount);
117                 ret_buf->tidStatus = CifsNew;
118                 ++ret_buf->tc_count;
119                 INIT_LIST_HEAD(&ret_buf->openFileList);
120                 INIT_LIST_HEAD(&ret_buf->tcon_list);
121                 spin_lock_init(&ret_buf->open_file_lock);
122                 mutex_init(&ret_buf->crfid.fid_mutex);
123                 ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid),
124                                              GFP_KERNEL);
125 #ifdef CONFIG_CIFS_STATS
126                 spin_lock_init(&ret_buf->stat_lock);
127 #endif
128         }
129         return ret_buf;
130 }
131 
132 void
133 tconInfoFree(struct cifs_tcon *buf_to_free)
134 {
135         if (buf_to_free == NULL) {
136                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
137                 return;
138         }
139         atomic_dec(&tconInfoAllocCount);
140         kfree(buf_to_free->nativeFileSystem);
141         kzfree(buf_to_free->password);
142         kfree(buf_to_free->crfid.fid);
143         kfree(buf_to_free);
144 }
145 
146 struct smb_hdr *
147 cifs_buf_get(void)
148 {
149         struct smb_hdr *ret_buf = NULL;
150         /*
151          * SMB2 header is bigger than CIFS one - no problems to clean some
152          * more bytes for CIFS.
153          */
154         size_t buf_size = sizeof(struct smb2_sync_hdr);
155 
156         /*
157          * We could use negotiated size instead of max_msgsize -
158          * but it may be more efficient to always alloc same size
159          * albeit slightly larger than necessary and maxbuffersize
160          * defaults to this and can not be bigger.
161          */
162         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
163 
164         /* clear the first few header bytes */
165         /* for most paths, more is cleared in header_assemble */
166         memset(ret_buf, 0, buf_size + 3);
167         atomic_inc(&bufAllocCount);
168 #ifdef CONFIG_CIFS_STATS2
169         atomic_inc(&totBufAllocCount);
170 #endif /* CONFIG_CIFS_STATS2 */
171 
172         return ret_buf;
173 }
174 
175 void
176 cifs_buf_release(void *buf_to_free)
177 {
178         if (buf_to_free == NULL) {
179                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
180                 return;
181         }
182         mempool_free(buf_to_free, cifs_req_poolp);
183 
184         atomic_dec(&bufAllocCount);
185         return;
186 }
187 
188 struct smb_hdr *
189 cifs_small_buf_get(void)
190 {
191         struct smb_hdr *ret_buf = NULL;
192 
193 /* We could use negotiated size instead of max_msgsize -
194    but it may be more efficient to always alloc same size
195    albeit slightly larger than necessary and maxbuffersize
196    defaults to this and can not be bigger */
197         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
198         /* No need to clear memory here, cleared in header assemble */
199         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
200         atomic_inc(&smBufAllocCount);
201 #ifdef CONFIG_CIFS_STATS2
202         atomic_inc(&totSmBufAllocCount);
203 #endif /* CONFIG_CIFS_STATS2 */
204 
205         return ret_buf;
206 }
207 
208 void
209 cifs_small_buf_release(void *buf_to_free)
210 {
211 
212         if (buf_to_free == NULL) {
213                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
214                 return;
215         }
216         mempool_free(buf_to_free, cifs_sm_req_poolp);
217 
218         atomic_dec(&smBufAllocCount);
219         return;
220 }
221 
222 void
223 free_rsp_buf(int resp_buftype, void *rsp)
224 {
225         if (resp_buftype == CIFS_SMALL_BUFFER)
226                 cifs_small_buf_release(rsp);
227         else if (resp_buftype == CIFS_LARGE_BUFFER)
228                 cifs_buf_release(rsp);
229 }
230 
231 /* NB: MID can not be set if treeCon not passed in, in that
232    case it is responsbility of caller to set the mid */
233 void
234 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
235                 const struct cifs_tcon *treeCon, int word_count
236                 /* length of fixed section (word count) in two byte units  */)
237 {
238         char *temp = (char *) buffer;
239 
240         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
241 
242         buffer->smb_buf_length = cpu_to_be32(
243             (2 * word_count) + sizeof(struct smb_hdr) -
244             4 /*  RFC 1001 length field does not count */  +
245             2 /* for bcc field itself */) ;
246 
247         buffer->Protocol[0] = 0xFF;
248         buffer->Protocol[1] = 'S';
249         buffer->Protocol[2] = 'M';
250         buffer->Protocol[3] = 'B';
251         buffer->Command = smb_command;
252         buffer->Flags = 0x00;   /* case sensitive */
253         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
254         buffer->Pid = cpu_to_le16((__u16)current->tgid);
255         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
256         if (treeCon) {
257                 buffer->Tid = treeCon->tid;
258                 if (treeCon->ses) {
259                         if (treeCon->ses->capabilities & CAP_UNICODE)
260                                 buffer->Flags2 |= SMBFLG2_UNICODE;
261                         if (treeCon->ses->capabilities & CAP_STATUS32)
262                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
263 
264                         /* Uid is not converted */
265                         buffer->Uid = treeCon->ses->Suid;
266                         buffer->Mid = get_next_mid(treeCon->ses->server);
267                 }
268                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
269                         buffer->Flags2 |= SMBFLG2_DFS;
270                 if (treeCon->nocase)
271                         buffer->Flags  |= SMBFLG_CASELESS;
272                 if ((treeCon->ses) && (treeCon->ses->server))
273                         if (treeCon->ses->server->sign)
274                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
275         }
276 
277 /*  endian conversion of flags is now done just before sending */
278         buffer->WordCount = (char) word_count;
279         return;
280 }
281 
282 static int
283 check_smb_hdr(struct smb_hdr *smb)
284 {
285         /* does it have the right SMB "signature" ? */
286         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
287                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
288                          *(unsigned int *)smb->Protocol);
289                 return 1;
290         }
291 
292         /* if it's a response then accept */
293         if (smb->Flags & SMBFLG_RESPONSE)
294                 return 0;
295 
296         /* only one valid case where server sends us request */
297         if (smb->Command == SMB_COM_LOCKING_ANDX)
298                 return 0;
299 
300         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
301                  get_mid(smb));
302         return 1;
303 }
304 
305 int
306 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
307 {
308         struct smb_hdr *smb = (struct smb_hdr *)buf;
309         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
310         __u32 clc_len;  /* calculated length */
311         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
312                  total_read, rfclen);
313 
314         /* is this frame too small to even get to a BCC? */
315         if (total_read < 2 + sizeof(struct smb_hdr)) {
316                 if ((total_read >= sizeof(struct smb_hdr) - 1)
317                             && (smb->Status.CifsError != 0)) {
318                         /* it's an error return */
319                         smb->WordCount = 0;
320                         /* some error cases do not return wct and bcc */
321                         return 0;
322                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
323                                 (smb->WordCount == 0)) {
324                         char *tmp = (char *)smb;
325                         /* Need to work around a bug in two servers here */
326                         /* First, check if the part of bcc they sent was zero */
327                         if (tmp[sizeof(struct smb_hdr)] == 0) {
328                                 /* some servers return only half of bcc
329                                  * on simple responses (wct, bcc both zero)
330                                  * in particular have seen this on
331                                  * ulogoffX and FindClose. This leaves
332                                  * one byte of bcc potentially unitialized
333                                  */
334                                 /* zero rest of bcc */
335                                 tmp[sizeof(struct smb_hdr)+1] = 0;
336                                 return 0;
337                         }
338                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
339                 } else {
340                         cifs_dbg(VFS, "Length less than smb header size\n");
341                 }
342                 return -EIO;
343         }
344 
345         /* otherwise, there is enough to get to the BCC */
346         if (check_smb_hdr(smb))
347                 return -EIO;
348         clc_len = smbCalcSize(smb, server);
349 
350         if (4 + rfclen != total_read) {
351                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
352                          rfclen);
353                 return -EIO;
354         }
355 
356         if (4 + rfclen != clc_len) {
357                 __u16 mid = get_mid(smb);
358                 /* check if bcc wrapped around for large read responses */
359                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
360                         /* check if lengths match mod 64K */
361                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
362                                 return 0; /* bcc wrapped */
363                 }
364                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
365                          clc_len, 4 + rfclen, mid);
366 
367                 if (4 + rfclen < clc_len) {
368                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
369                                  rfclen, mid);
370                         return -EIO;
371                 } else if (rfclen > clc_len + 512) {
372                         /*
373                          * Some servers (Windows XP in particular) send more
374                          * data than the lengths in the SMB packet would
375                          * indicate on certain calls (byte range locks and
376                          * trans2 find first calls in particular). While the
377                          * client can handle such a frame by ignoring the
378                          * trailing data, we choose limit the amount of extra
379                          * data to 512 bytes.
380                          */
381                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
382                                  rfclen, mid);
383                         return -EIO;
384                 }
385         }
386         return 0;
387 }
388 
389 bool
390 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
391 {
392         struct smb_hdr *buf = (struct smb_hdr *)buffer;
393         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
394         struct list_head *tmp, *tmp1, *tmp2;
395         struct cifs_ses *ses;
396         struct cifs_tcon *tcon;
397         struct cifsInodeInfo *pCifsInode;
398         struct cifsFileInfo *netfile;
399 
400         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
401         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
402            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
403                 struct smb_com_transaction_change_notify_rsp *pSMBr =
404                         (struct smb_com_transaction_change_notify_rsp *)buf;
405                 struct file_notify_information *pnotify;
406                 __u32 data_offset = 0;
407                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
408 
409                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
410                         data_offset = le32_to_cpu(pSMBr->DataOffset);
411 
412                         if (data_offset >
413                             len - sizeof(struct file_notify_information)) {
414                                 cifs_dbg(FYI, "invalid data_offset %u\n",
415                                          data_offset);
416                                 return true;
417                         }
418                         pnotify = (struct file_notify_information *)
419                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
420                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
421                                  pnotify->FileName, pnotify->Action);
422                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
423                                 sizeof(struct smb_hdr)+60); */
424                         return true;
425                 }
426                 if (pSMBr->hdr.Status.CifsError) {
427                         cifs_dbg(FYI, "notify err 0x%x\n",
428                                  pSMBr->hdr.Status.CifsError);
429                         return true;
430                 }
431                 return false;
432         }
433         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
434                 return false;
435         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
436                 /* no sense logging error on invalid handle on oplock
437                    break - harmless race between close request and oplock
438                    break response is expected from time to time writing out
439                    large dirty files cached on the client */
440                 if ((NT_STATUS_INVALID_HANDLE) ==
441                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
442                         cifs_dbg(FYI, "invalid handle on oplock break\n");
443                         return true;
444                 } else if (ERRbadfid ==
445                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
446                         return true;
447                 } else {
448                         return false; /* on valid oplock brk we get "request" */
449                 }
450         }
451         if (pSMB->hdr.WordCount != 8)
452                 return false;
453 
454         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
455                  pSMB->LockType, pSMB->OplockLevel);
456         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
457                 return false;
458 
459         /* look up tcon based on tid & uid */
460         spin_lock(&cifs_tcp_ses_lock);
461         list_for_each(tmp, &srv->smb_ses_list) {
462                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
463                 list_for_each(tmp1, &ses->tcon_list) {
464                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
465                         if (tcon->tid != buf->Tid)
466                                 continue;
467 
468                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
469                         spin_lock(&tcon->open_file_lock);
470                         list_for_each(tmp2, &tcon->openFileList) {
471                                 netfile = list_entry(tmp2, struct cifsFileInfo,
472                                                      tlist);
473                                 if (pSMB->Fid != netfile->fid.netfid)
474                                         continue;
475 
476                                 cifs_dbg(FYI, "file id match, oplock break\n");
477                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
478 
479                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
480                                         &pCifsInode->flags);
481 
482                                 /*
483                                  * Set flag if the server downgrades the oplock
484                                  * to L2 else clear.
485                                  */
486                                 if (pSMB->OplockLevel)
487                                         set_bit(
488                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
489                                            &pCifsInode->flags);
490                                 else
491                                         clear_bit(
492                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
493                                            &pCifsInode->flags);
494 
495                                 queue_work(cifsoplockd_wq,
496                                            &netfile->oplock_break);
497                                 netfile->oplock_break_cancelled = false;
498 
499                                 spin_unlock(&tcon->open_file_lock);
500                                 spin_unlock(&cifs_tcp_ses_lock);
501                                 return true;
502                         }
503                         spin_unlock(&tcon->open_file_lock);
504                         spin_unlock(&cifs_tcp_ses_lock);
505                         cifs_dbg(FYI, "No matching file for oplock break\n");
506                         return true;
507                 }
508         }
509         spin_unlock(&cifs_tcp_ses_lock);
510         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
511         return true;
512 }
513 
514 void
515 dump_smb(void *buf, int smb_buf_length)
516 {
517         if (traceSMB == 0)
518                 return;
519 
520         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
521                        smb_buf_length, true);
522 }
523 
524 void
525 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
526 {
527         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
528                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
529                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s. This server doesn't seem to support them properly. Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n",
530                          cifs_sb_master_tcon(cifs_sb)->treeName);
531         }
532 }
533 
534 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
535 {
536         oplock &= 0xF;
537 
538         if (oplock == OPLOCK_EXCLUSIVE) {
539                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
540                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
541                          &cinode->vfs_inode);
542         } else if (oplock == OPLOCK_READ) {
543                 cinode->oplock = CIFS_CACHE_READ_FLG;
544                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
545                          &cinode->vfs_inode);
546         } else
547                 cinode->oplock = 0;
548 }
549 
550 /*
551  * We wait for oplock breaks to be processed before we attempt to perform
552  * writes.
553  */
554 int cifs_get_writer(struct cifsInodeInfo *cinode)
555 {
556         int rc;
557 
558 start:
559         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
560                          TASK_KILLABLE);
561         if (rc)
562                 return rc;
563 
564         spin_lock(&cinode->writers_lock);
565         if (!cinode->writers)
566                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
567         cinode->writers++;
568         /* Check to see if we have started servicing an oplock break */
569         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
570                 cinode->writers--;
571                 if (cinode->writers == 0) {
572                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
573                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
574                 }
575                 spin_unlock(&cinode->writers_lock);
576                 goto start;
577         }
578         spin_unlock(&cinode->writers_lock);
579         return 0;
580 }
581 
582 void cifs_put_writer(struct cifsInodeInfo *cinode)
583 {
584         spin_lock(&cinode->writers_lock);
585         cinode->writers--;
586         if (cinode->writers == 0) {
587                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
588                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
589         }
590         spin_unlock(&cinode->writers_lock);
591 }
592 
593 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
594 {
595         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
596         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
597 }
598 
599 bool
600 backup_cred(struct cifs_sb_info *cifs_sb)
601 {
602         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
603                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
604                         return true;
605         }
606         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
607                 if (in_group_p(cifs_sb->mnt_backupgid))
608                         return true;
609         }
610 
611         return false;
612 }
613 
614 void
615 cifs_del_pending_open(struct cifs_pending_open *open)
616 {
617         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
618         list_del(&open->olist);
619         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
620 }
621 
622 void
623 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
624                              struct cifs_pending_open *open)
625 {
626         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
627         open->oplock = CIFS_OPLOCK_NO_CHANGE;
628         open->tlink = tlink;
629         fid->pending_open = open;
630         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
631 }
632 
633 void
634 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
635                       struct cifs_pending_open *open)
636 {
637         spin_lock(&tlink_tcon(tlink)->open_file_lock);
638         cifs_add_pending_open_locked(fid, tlink, open);
639         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
640 }
641 
642 /* parses DFS refferal V3 structure
643  * caller is responsible for freeing target_nodes
644  * returns:
645  * - on success - 0
646  * - on failure - errno
647  */
648 int
649 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
650                     unsigned int *num_of_nodes,
651                     struct dfs_info3_param **target_nodes,
652                     const struct nls_table *nls_codepage, int remap,
653                     const char *searchName, bool is_unicode)
654 {
655         int i, rc = 0;
656         char *data_end;
657         struct dfs_referral_level_3 *ref;
658 
659         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
660 
661         if (*num_of_nodes < 1) {
662                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
663                          *num_of_nodes);
664                 rc = -EINVAL;
665                 goto parse_DFS_referrals_exit;
666         }
667 
668         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
669         if (ref->VersionNumber != cpu_to_le16(3)) {
670                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
671                          le16_to_cpu(ref->VersionNumber));
672                 rc = -EINVAL;
673                 goto parse_DFS_referrals_exit;
674         }
675 
676         /* get the upper boundary of the resp buffer */
677         data_end = (char *)rsp + rsp_size;
678 
679         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
680                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
681 
682         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
683                                 GFP_KERNEL);
684         if (*target_nodes == NULL) {
685                 rc = -ENOMEM;
686                 goto parse_DFS_referrals_exit;
687         }
688 
689         /* collect necessary data from referrals */
690         for (i = 0; i < *num_of_nodes; i++) {
691                 char *temp;
692                 int max_len;
693                 struct dfs_info3_param *node = (*target_nodes)+i;
694 
695                 node->flags = le32_to_cpu(rsp->DFSFlags);
696                 if (is_unicode) {
697                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
698                                                 GFP_KERNEL);
699                         if (tmp == NULL) {
700                                 rc = -ENOMEM;
701                                 goto parse_DFS_referrals_exit;
702                         }
703                         cifsConvertToUTF16((__le16 *) tmp, searchName,
704                                            PATH_MAX, nls_codepage, remap);
705                         node->path_consumed = cifs_utf16_bytes(tmp,
706                                         le16_to_cpu(rsp->PathConsumed),
707                                         nls_codepage);
708                         kfree(tmp);
709                 } else
710                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
711 
712                 node->server_type = le16_to_cpu(ref->ServerType);
713                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
714 
715                 /* copy DfsPath */
716                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
717                 max_len = data_end - temp;
718                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
719                                                 is_unicode, nls_codepage);
720                 if (!node->path_name) {
721                         rc = -ENOMEM;
722                         goto parse_DFS_referrals_exit;
723                 }
724 
725                 /* copy link target UNC */
726                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
727                 max_len = data_end - temp;
728                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
729                                                 is_unicode, nls_codepage);
730                 if (!node->node_name) {
731                         rc = -ENOMEM;
732                         goto parse_DFS_referrals_exit;
733                 }
734 
735                 ref++;
736         }
737 
738 parse_DFS_referrals_exit:
739         if (rc) {
740                 free_dfs_info_array(*target_nodes, *num_of_nodes);
741                 *target_nodes = NULL;
742                 *num_of_nodes = 0;
743         }
744         return rc;
745 }
746 
747 struct cifs_aio_ctx *
748 cifs_aio_ctx_alloc(void)
749 {
750         struct cifs_aio_ctx *ctx;
751 
752         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
753         if (!ctx)
754                 return NULL;
755 
756         INIT_LIST_HEAD(&ctx->list);
757         mutex_init(&ctx->aio_mutex);
758         init_completion(&ctx->done);
759         kref_init(&ctx->refcount);
760         return ctx;
761 }
762 
763 void
764 cifs_aio_ctx_release(struct kref *refcount)
765 {
766         struct cifs_aio_ctx *ctx = container_of(refcount,
767                                         struct cifs_aio_ctx, refcount);
768 
769         cifsFileInfo_put(ctx->cfile);
770         kvfree(ctx->bv);
771         kfree(ctx);
772 }
773 
774 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
775 
776 int
777 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
778 {
779         ssize_t rc;
780         unsigned int cur_npages;
781         unsigned int npages = 0;
782         unsigned int i;
783         size_t len;
784         size_t count = iov_iter_count(iter);
785         unsigned int saved_len;
786         size_t start;
787         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
788         struct page **pages = NULL;
789         struct bio_vec *bv = NULL;
790 
791         if (iter->type & ITER_KVEC) {
792                 memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
793                 ctx->len = count;
794                 iov_iter_advance(iter, count);
795                 return 0;
796         }
797 
798         if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
799                 bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
800                                    GFP_KERNEL);
801 
802         if (!bv) {
803                 bv = vmalloc(array_size(max_pages, sizeof(struct bio_vec)));
804                 if (!bv)
805                         return -ENOMEM;
806         }
807 
808         if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
809                 pages = kmalloc_array(max_pages, sizeof(struct page *),
810                                       GFP_KERNEL);
811 
812         if (!pages) {
813                 pages = vmalloc(array_size(max_pages, sizeof(struct page *)));
814                 if (!pages) {
815                         kvfree(bv);
816                         return -ENOMEM;
817                 }
818         }
819 
820         saved_len = count;
821 
822         while (count && npages < max_pages) {
823                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
824                 if (rc < 0) {
825                         cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
826                         break;
827                 }
828 
829                 if (rc > count) {
830                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
831                                  count);
832                         break;
833                 }
834 
835                 iov_iter_advance(iter, rc);
836                 count -= rc;
837                 rc += start;
838                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
839 
840                 if (npages + cur_npages > max_pages) {
841                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
842                                  npages + cur_npages, max_pages);
843                         break;
844                 }
845 
846                 for (i = 0; i < cur_npages; i++) {
847                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
848                         bv[npages + i].bv_page = pages[i];
849                         bv[npages + i].bv_offset = start;
850                         bv[npages + i].bv_len = len - start;
851                         rc -= len;
852                         start = 0;
853                 }
854 
855                 npages += cur_npages;
856         }
857 
858         kvfree(pages);
859         ctx->bv = bv;
860         ctx->len = saved_len - count;
861         ctx->npages = npages;
862         iov_iter_bvec(&ctx->iter, ITER_BVEC | rw, ctx->bv, npages, ctx->len);
863         return 0;
864 }
865 
866 /**
867  * cifs_alloc_hash - allocate hash and hash context together
868  *
869  * The caller has to make sure @sdesc is initialized to either NULL or
870  * a valid context. Both can be freed via cifs_free_hash().
871  */
872 int
873 cifs_alloc_hash(const char *name,
874                 struct crypto_shash **shash, struct sdesc **sdesc)
875 {
876         int rc = 0;
877         size_t size;
878 
879         if (*sdesc != NULL)
880                 return 0;
881 
882         *shash = crypto_alloc_shash(name, 0, 0);
883         if (IS_ERR(*shash)) {
884                 cifs_dbg(VFS, "could not allocate crypto %s\n", name);
885                 rc = PTR_ERR(*shash);
886                 *shash = NULL;
887                 *sdesc = NULL;
888                 return rc;
889         }
890 
891         size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
892         *sdesc = kmalloc(size, GFP_KERNEL);
893         if (*sdesc == NULL) {
894                 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
895                 crypto_free_shash(*shash);
896                 *shash = NULL;
897                 return -ENOMEM;
898         }
899 
900         (*sdesc)->shash.tfm = *shash;
901         (*sdesc)->shash.flags = 0x0;
902         return 0;
903 }
904 
905 /**
906  * cifs_free_hash - free hash and hash context together
907  *
908  * Freeing a NULL hash or context is safe.
909  */
910 void
911 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
912 {
913         kfree(*sdesc);
914         *sdesc = NULL;
915         if (*shash)
916                 crypto_free_shash(*shash);
917         *shash = NULL;
918 }
919 
920 /**
921  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
922  * Input: rqst - a smb_rqst, page - a page index for rqst
923  * Output: *len - the length for this page, *offset - the offset for this page
924  */
925 void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
926                                 unsigned int *len, unsigned int *offset)
927 {
928         *len = rqst->rq_pagesz;
929         *offset = (page == 0) ? rqst->rq_offset : 0;
930 
931         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
932                 *len = rqst->rq_tailsz;
933         else if (page == 0)
934                 *len = rqst->rq_pagesz - rqst->rq_offset;
935 }
936 

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