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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         }
 86         return ret_buf;
 87 }
 88 
 89 void
 90 sesInfoFree(struct cifs_ses *buf_to_free)
 91 {
 92         if (buf_to_free == NULL) {
 93                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
 94                 return;
 95         }
 96 
 97         atomic_dec(&sesInfoAllocCount);
 98         kfree(buf_to_free->serverOS);
 99         kfree(buf_to_free->serverDomain);
100         kfree(buf_to_free->serverNOS);
101         kzfree(buf_to_free->password);
102         kfree(buf_to_free->user_name);
103         kfree(buf_to_free->domainName);
104         kzfree(buf_to_free->auth_key.response);
105         kzfree(buf_to_free);
106 }
107 
108 struct cifs_tcon *
109 tconInfoAlloc(void)
110 {
111         struct cifs_tcon *ret_buf;
112         ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
113         if (ret_buf) {
114                 atomic_inc(&tconInfoAllocCount);
115                 ret_buf->tidStatus = CifsNew;
116                 ++ret_buf->tc_count;
117                 INIT_LIST_HEAD(&ret_buf->openFileList);
118                 INIT_LIST_HEAD(&ret_buf->tcon_list);
119                 spin_lock_init(&ret_buf->open_file_lock);
120 #ifdef CONFIG_CIFS_STATS
121                 spin_lock_init(&ret_buf->stat_lock);
122 #endif
123         }
124         return ret_buf;
125 }
126 
127 void
128 tconInfoFree(struct cifs_tcon *buf_to_free)
129 {
130         if (buf_to_free == NULL) {
131                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
132                 return;
133         }
134         atomic_dec(&tconInfoAllocCount);
135         kfree(buf_to_free->nativeFileSystem);
136         kzfree(buf_to_free->password);
137         kfree(buf_to_free);
138 }
139 
140 struct smb_hdr *
141 cifs_buf_get(void)
142 {
143         struct smb_hdr *ret_buf = NULL;
144         /*
145          * SMB2 header is bigger than CIFS one - no problems to clean some
146          * more bytes for CIFS.
147          */
148         size_t buf_size = sizeof(struct smb2_hdr);
149 
150         /*
151          * We could use negotiated size instead of max_msgsize -
152          * but it may be more efficient to always alloc same size
153          * albeit slightly larger than necessary and maxbuffersize
154          * defaults to this and can not be bigger.
155          */
156         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
157 
158         /* clear the first few header bytes */
159         /* for most paths, more is cleared in header_assemble */
160         memset(ret_buf, 0, buf_size + 3);
161         atomic_inc(&bufAllocCount);
162 #ifdef CONFIG_CIFS_STATS2
163         atomic_inc(&totBufAllocCount);
164 #endif /* CONFIG_CIFS_STATS2 */
165 
166         return ret_buf;
167 }
168 
169 void
170 cifs_buf_release(void *buf_to_free)
171 {
172         if (buf_to_free == NULL) {
173                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
174                 return;
175         }
176         mempool_free(buf_to_free, cifs_req_poolp);
177 
178         atomic_dec(&bufAllocCount);
179         return;
180 }
181 
182 struct smb_hdr *
183 cifs_small_buf_get(void)
184 {
185         struct smb_hdr *ret_buf = NULL;
186 
187 /* We could use negotiated size instead of max_msgsize -
188    but it may be more efficient to always alloc same size
189    albeit slightly larger than necessary and maxbuffersize
190    defaults to this and can not be bigger */
191         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
192         /* No need to clear memory here, cleared in header assemble */
193         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
194         atomic_inc(&smBufAllocCount);
195 #ifdef CONFIG_CIFS_STATS2
196         atomic_inc(&totSmBufAllocCount);
197 #endif /* CONFIG_CIFS_STATS2 */
198 
199         return ret_buf;
200 }
201 
202 void
203 cifs_small_buf_release(void *buf_to_free)
204 {
205 
206         if (buf_to_free == NULL) {
207                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
208                 return;
209         }
210         mempool_free(buf_to_free, cifs_sm_req_poolp);
211 
212         atomic_dec(&smBufAllocCount);
213         return;
214 }
215 
216 void
217 free_rsp_buf(int resp_buftype, void *rsp)
218 {
219         if (resp_buftype == CIFS_SMALL_BUFFER)
220                 cifs_small_buf_release(rsp);
221         else if (resp_buftype == CIFS_LARGE_BUFFER)
222                 cifs_buf_release(rsp);
223 }
224 
225 /* NB: MID can not be set if treeCon not passed in, in that
226    case it is responsbility of caller to set the mid */
227 void
228 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
229                 const struct cifs_tcon *treeCon, int word_count
230                 /* length of fixed section (word count) in two byte units  */)
231 {
232         char *temp = (char *) buffer;
233 
234         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
235 
236         buffer->smb_buf_length = cpu_to_be32(
237             (2 * word_count) + sizeof(struct smb_hdr) -
238             4 /*  RFC 1001 length field does not count */  +
239             2 /* for bcc field itself */) ;
240 
241         buffer->Protocol[0] = 0xFF;
242         buffer->Protocol[1] = 'S';
243         buffer->Protocol[2] = 'M';
244         buffer->Protocol[3] = 'B';
245         buffer->Command = smb_command;
246         buffer->Flags = 0x00;   /* case sensitive */
247         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
248         buffer->Pid = cpu_to_le16((__u16)current->tgid);
249         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
250         if (treeCon) {
251                 buffer->Tid = treeCon->tid;
252                 if (treeCon->ses) {
253                         if (treeCon->ses->capabilities & CAP_UNICODE)
254                                 buffer->Flags2 |= SMBFLG2_UNICODE;
255                         if (treeCon->ses->capabilities & CAP_STATUS32)
256                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
257 
258                         /* Uid is not converted */
259                         buffer->Uid = treeCon->ses->Suid;
260                         buffer->Mid = get_next_mid(treeCon->ses->server);
261                 }
262                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
263                         buffer->Flags2 |= SMBFLG2_DFS;
264                 if (treeCon->nocase)
265                         buffer->Flags  |= SMBFLG_CASELESS;
266                 if ((treeCon->ses) && (treeCon->ses->server))
267                         if (treeCon->ses->server->sign)
268                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
269         }
270 
271 /*  endian conversion of flags is now done just before sending */
272         buffer->WordCount = (char) word_count;
273         return;
274 }
275 
276 static int
277 check_smb_hdr(struct smb_hdr *smb)
278 {
279         /* does it have the right SMB "signature" ? */
280         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
281                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
282                          *(unsigned int *)smb->Protocol);
283                 return 1;
284         }
285 
286         /* if it's a response then accept */
287         if (smb->Flags & SMBFLG_RESPONSE)
288                 return 0;
289 
290         /* only one valid case where server sends us request */
291         if (smb->Command == SMB_COM_LOCKING_ANDX)
292                 return 0;
293 
294         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
295                  get_mid(smb));
296         return 1;
297 }
298 
299 int
300 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
301 {
302         struct smb_hdr *smb = (struct smb_hdr *)buf;
303         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
304         __u32 clc_len;  /* calculated length */
305         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
306                  total_read, rfclen);
307 
308         /* is this frame too small to even get to a BCC? */
309         if (total_read < 2 + sizeof(struct smb_hdr)) {
310                 if ((total_read >= sizeof(struct smb_hdr) - 1)
311                             && (smb->Status.CifsError != 0)) {
312                         /* it's an error return */
313                         smb->WordCount = 0;
314                         /* some error cases do not return wct and bcc */
315                         return 0;
316                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
317                                 (smb->WordCount == 0)) {
318                         char *tmp = (char *)smb;
319                         /* Need to work around a bug in two servers here */
320                         /* First, check if the part of bcc they sent was zero */
321                         if (tmp[sizeof(struct smb_hdr)] == 0) {
322                                 /* some servers return only half of bcc
323                                  * on simple responses (wct, bcc both zero)
324                                  * in particular have seen this on
325                                  * ulogoffX and FindClose. This leaves
326                                  * one byte of bcc potentially unitialized
327                                  */
328                                 /* zero rest of bcc */
329                                 tmp[sizeof(struct smb_hdr)+1] = 0;
330                                 return 0;
331                         }
332                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
333                 } else {
334                         cifs_dbg(VFS, "Length less than smb header size\n");
335                 }
336                 return -EIO;
337         }
338 
339         /* otherwise, there is enough to get to the BCC */
340         if (check_smb_hdr(smb))
341                 return -EIO;
342         clc_len = smbCalcSize(smb);
343 
344         if (4 + rfclen != total_read) {
345                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
346                          rfclen);
347                 return -EIO;
348         }
349 
350         if (4 + rfclen != clc_len) {
351                 __u16 mid = get_mid(smb);
352                 /* check if bcc wrapped around for large read responses */
353                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
354                         /* check if lengths match mod 64K */
355                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
356                                 return 0; /* bcc wrapped */
357                 }
358                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
359                          clc_len, 4 + rfclen, mid);
360 
361                 if (4 + rfclen < clc_len) {
362                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
363                                  rfclen, mid);
364                         return -EIO;
365                 } else if (rfclen > clc_len + 512) {
366                         /*
367                          * Some servers (Windows XP in particular) send more
368                          * data than the lengths in the SMB packet would
369                          * indicate on certain calls (byte range locks and
370                          * trans2 find first calls in particular). While the
371                          * client can handle such a frame by ignoring the
372                          * trailing data, we choose limit the amount of extra
373                          * data to 512 bytes.
374                          */
375                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
376                                  rfclen, mid);
377                         return -EIO;
378                 }
379         }
380         return 0;
381 }
382 
383 bool
384 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
385 {
386         struct smb_hdr *buf = (struct smb_hdr *)buffer;
387         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
388         struct list_head *tmp, *tmp1, *tmp2;
389         struct cifs_ses *ses;
390         struct cifs_tcon *tcon;
391         struct cifsInodeInfo *pCifsInode;
392         struct cifsFileInfo *netfile;
393 
394         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
395         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
396            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
397                 struct smb_com_transaction_change_notify_rsp *pSMBr =
398                         (struct smb_com_transaction_change_notify_rsp *)buf;
399                 struct file_notify_information *pnotify;
400                 __u32 data_offset = 0;
401                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
402                         data_offset = le32_to_cpu(pSMBr->DataOffset);
403 
404                         pnotify = (struct file_notify_information *)
405                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
406                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
407                                  pnotify->FileName, pnotify->Action);
408                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
409                                 sizeof(struct smb_hdr)+60); */
410                         return true;
411                 }
412                 if (pSMBr->hdr.Status.CifsError) {
413                         cifs_dbg(FYI, "notify err 0x%x\n",
414                                  pSMBr->hdr.Status.CifsError);
415                         return true;
416                 }
417                 return false;
418         }
419         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
420                 return false;
421         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
422                 /* no sense logging error on invalid handle on oplock
423                    break - harmless race between close request and oplock
424                    break response is expected from time to time writing out
425                    large dirty files cached on the client */
426                 if ((NT_STATUS_INVALID_HANDLE) ==
427                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
428                         cifs_dbg(FYI, "invalid handle on oplock break\n");
429                         return true;
430                 } else if (ERRbadfid ==
431                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
432                         return true;
433                 } else {
434                         return false; /* on valid oplock brk we get "request" */
435                 }
436         }
437         if (pSMB->hdr.WordCount != 8)
438                 return false;
439 
440         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
441                  pSMB->LockType, pSMB->OplockLevel);
442         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
443                 return false;
444 
445         /* look up tcon based on tid & uid */
446         spin_lock(&cifs_tcp_ses_lock);
447         list_for_each(tmp, &srv->smb_ses_list) {
448                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
449                 list_for_each(tmp1, &ses->tcon_list) {
450                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
451                         if (tcon->tid != buf->Tid)
452                                 continue;
453 
454                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
455                         spin_lock(&tcon->open_file_lock);
456                         list_for_each(tmp2, &tcon->openFileList) {
457                                 netfile = list_entry(tmp2, struct cifsFileInfo,
458                                                      tlist);
459                                 if (pSMB->Fid != netfile->fid.netfid)
460                                         continue;
461 
462                                 cifs_dbg(FYI, "file id match, oplock break\n");
463                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
464 
465                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
466                                         &pCifsInode->flags);
467 
468                                 /*
469                                  * Set flag if the server downgrades the oplock
470                                  * to L2 else clear.
471                                  */
472                                 if (pSMB->OplockLevel)
473                                         set_bit(
474                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
475                                            &pCifsInode->flags);
476                                 else
477                                         clear_bit(
478                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
479                                            &pCifsInode->flags);
480 
481                                 queue_work(cifsoplockd_wq,
482                                            &netfile->oplock_break);
483                                 netfile->oplock_break_cancelled = false;
484 
485                                 spin_unlock(&tcon->open_file_lock);
486                                 spin_unlock(&cifs_tcp_ses_lock);
487                                 return true;
488                         }
489                         spin_unlock(&tcon->open_file_lock);
490                         spin_unlock(&cifs_tcp_ses_lock);
491                         cifs_dbg(FYI, "No matching file for oplock break\n");
492                         return true;
493                 }
494         }
495         spin_unlock(&cifs_tcp_ses_lock);
496         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
497         return true;
498 }
499 
500 void
501 dump_smb(void *buf, int smb_buf_length)
502 {
503         if (traceSMB == 0)
504                 return;
505 
506         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
507                        smb_buf_length, true);
508 }
509 
510 void
511 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
512 {
513         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
514                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
515                 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",
516                          cifs_sb_master_tcon(cifs_sb)->treeName);
517         }
518 }
519 
520 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
521 {
522         oplock &= 0xF;
523 
524         if (oplock == OPLOCK_EXCLUSIVE) {
525                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
526                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
527                          &cinode->vfs_inode);
528         } else if (oplock == OPLOCK_READ) {
529                 cinode->oplock = CIFS_CACHE_READ_FLG;
530                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
531                          &cinode->vfs_inode);
532         } else
533                 cinode->oplock = 0;
534 }
535 
536 /*
537  * We wait for oplock breaks to be processed before we attempt to perform
538  * writes.
539  */
540 int cifs_get_writer(struct cifsInodeInfo *cinode)
541 {
542         int rc;
543 
544 start:
545         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
546                          TASK_KILLABLE);
547         if (rc)
548                 return rc;
549 
550         spin_lock(&cinode->writers_lock);
551         if (!cinode->writers)
552                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
553         cinode->writers++;
554         /* Check to see if we have started servicing an oplock break */
555         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
556                 cinode->writers--;
557                 if (cinode->writers == 0) {
558                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
559                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
560                 }
561                 spin_unlock(&cinode->writers_lock);
562                 goto start;
563         }
564         spin_unlock(&cinode->writers_lock);
565         return 0;
566 }
567 
568 void cifs_put_writer(struct cifsInodeInfo *cinode)
569 {
570         spin_lock(&cinode->writers_lock);
571         cinode->writers--;
572         if (cinode->writers == 0) {
573                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
574                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
575         }
576         spin_unlock(&cinode->writers_lock);
577 }
578 
579 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
580 {
581         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
582         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
583 }
584 
585 bool
586 backup_cred(struct cifs_sb_info *cifs_sb)
587 {
588         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
589                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
590                         return true;
591         }
592         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
593                 if (in_group_p(cifs_sb->mnt_backupgid))
594                         return true;
595         }
596 
597         return false;
598 }
599 
600 void
601 cifs_del_pending_open(struct cifs_pending_open *open)
602 {
603         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
604         list_del(&open->olist);
605         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
606 }
607 
608 void
609 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
610                              struct cifs_pending_open *open)
611 {
612         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
613         open->oplock = CIFS_OPLOCK_NO_CHANGE;
614         open->tlink = tlink;
615         fid->pending_open = open;
616         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
617 }
618 
619 void
620 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
621                       struct cifs_pending_open *open)
622 {
623         spin_lock(&tlink_tcon(tlink)->open_file_lock);
624         cifs_add_pending_open_locked(fid, tlink, open);
625         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
626 }
627 
628 /* parses DFS refferal V3 structure
629  * caller is responsible for freeing target_nodes
630  * returns:
631  * - on success - 0
632  * - on failure - errno
633  */
634 int
635 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
636                     unsigned int *num_of_nodes,
637                     struct dfs_info3_param **target_nodes,
638                     const struct nls_table *nls_codepage, int remap,
639                     const char *searchName, bool is_unicode)
640 {
641         int i, rc = 0;
642         char *data_end;
643         struct dfs_referral_level_3 *ref;
644 
645         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
646 
647         if (*num_of_nodes < 1) {
648                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
649                          *num_of_nodes);
650                 rc = -EINVAL;
651                 goto parse_DFS_referrals_exit;
652         }
653 
654         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
655         if (ref->VersionNumber != cpu_to_le16(3)) {
656                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
657                          le16_to_cpu(ref->VersionNumber));
658                 rc = -EINVAL;
659                 goto parse_DFS_referrals_exit;
660         }
661 
662         /* get the upper boundary of the resp buffer */
663         data_end = (char *)rsp + rsp_size;
664 
665         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
666                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
667 
668         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
669                                 GFP_KERNEL);
670         if (*target_nodes == NULL) {
671                 rc = -ENOMEM;
672                 goto parse_DFS_referrals_exit;
673         }
674 
675         /* collect necessary data from referrals */
676         for (i = 0; i < *num_of_nodes; i++) {
677                 char *temp;
678                 int max_len;
679                 struct dfs_info3_param *node = (*target_nodes)+i;
680 
681                 node->flags = le32_to_cpu(rsp->DFSFlags);
682                 if (is_unicode) {
683                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
684                                                 GFP_KERNEL);
685                         if (tmp == NULL) {
686                                 rc = -ENOMEM;
687                                 goto parse_DFS_referrals_exit;
688                         }
689                         cifsConvertToUTF16((__le16 *) tmp, searchName,
690                                            PATH_MAX, nls_codepage, remap);
691                         node->path_consumed = cifs_utf16_bytes(tmp,
692                                         le16_to_cpu(rsp->PathConsumed),
693                                         nls_codepage);
694                         kfree(tmp);
695                 } else
696                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
697 
698                 node->server_type = le16_to_cpu(ref->ServerType);
699                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
700 
701                 /* copy DfsPath */
702                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
703                 max_len = data_end - temp;
704                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
705                                                 is_unicode, nls_codepage);
706                 if (!node->path_name) {
707                         rc = -ENOMEM;
708                         goto parse_DFS_referrals_exit;
709                 }
710 
711                 /* copy link target UNC */
712                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
713                 max_len = data_end - temp;
714                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
715                                                 is_unicode, nls_codepage);
716                 if (!node->node_name) {
717                         rc = -ENOMEM;
718                         goto parse_DFS_referrals_exit;
719                 }
720 
721                 ref++;
722         }
723 
724 parse_DFS_referrals_exit:
725         if (rc) {
726                 free_dfs_info_array(*target_nodes, *num_of_nodes);
727                 *target_nodes = NULL;
728                 *num_of_nodes = 0;
729         }
730         return rc;
731 }
732 
733 struct cifs_aio_ctx *
734 cifs_aio_ctx_alloc(void)
735 {
736         struct cifs_aio_ctx *ctx;
737 
738         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
739         if (!ctx)
740                 return NULL;
741 
742         INIT_LIST_HEAD(&ctx->list);
743         mutex_init(&ctx->aio_mutex);
744         init_completion(&ctx->done);
745         kref_init(&ctx->refcount);
746         return ctx;
747 }
748 
749 void
750 cifs_aio_ctx_release(struct kref *refcount)
751 {
752         struct cifs_aio_ctx *ctx = container_of(refcount,
753                                         struct cifs_aio_ctx, refcount);
754 
755         cifsFileInfo_put(ctx->cfile);
756         kvfree(ctx->bv);
757         kfree(ctx);
758 }
759 
760 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
761 
762 int
763 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
764 {
765         ssize_t rc;
766         unsigned int cur_npages;
767         unsigned int npages = 0;
768         unsigned int i;
769         size_t len;
770         size_t count = iov_iter_count(iter);
771         unsigned int saved_len;
772         size_t start;
773         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
774         struct page **pages = NULL;
775         struct bio_vec *bv = NULL;
776 
777         if (iter->type & ITER_KVEC) {
778                 memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
779                 ctx->len = count;
780                 iov_iter_advance(iter, count);
781                 return 0;
782         }
783 
784         if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
785                 bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
786                                    GFP_KERNEL);
787 
788         if (!bv) {
789                 bv = vmalloc(max_pages * sizeof(struct bio_vec));
790                 if (!bv)
791                         return -ENOMEM;
792         }
793 
794         if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
795                 pages = kmalloc_array(max_pages, sizeof(struct page *),
796                                       GFP_KERNEL);
797 
798         if (!pages) {
799                 pages = vmalloc(max_pages * sizeof(struct page *));
800                 if (!pages) {
801                         kvfree(bv);
802                         return -ENOMEM;
803                 }
804         }
805 
806         saved_len = count;
807 
808         while (count && npages < max_pages) {
809                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
810                 if (rc < 0) {
811                         cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
812                         break;
813                 }
814 
815                 if (rc > count) {
816                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
817                                  count);
818                         break;
819                 }
820 
821                 iov_iter_advance(iter, rc);
822                 count -= rc;
823                 rc += start;
824                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
825 
826                 if (npages + cur_npages > max_pages) {
827                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
828                                  npages + cur_npages, max_pages);
829                         break;
830                 }
831 
832                 for (i = 0; i < cur_npages; i++) {
833                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
834                         bv[npages + i].bv_page = pages[i];
835                         bv[npages + i].bv_offset = start;
836                         bv[npages + i].bv_len = len - start;
837                         rc -= len;
838                         start = 0;
839                 }
840 
841                 npages += cur_npages;
842         }
843 
844         kvfree(pages);
845         ctx->bv = bv;
846         ctx->len = saved_len - count;
847         ctx->npages = npages;
848         iov_iter_bvec(&ctx->iter, ITER_BVEC | rw, ctx->bv, npages, ctx->len);
849         return 0;
850 }
851 
852 /**
853  * cifs_alloc_hash - allocate hash and hash context together
854  *
855  * The caller has to make sure @sdesc is initialized to either NULL or
856  * a valid context. Both can be freed via cifs_free_hash().
857  */
858 int
859 cifs_alloc_hash(const char *name,
860                 struct crypto_shash **shash, struct sdesc **sdesc)
861 {
862         int rc = 0;
863         size_t size;
864 
865         if (*sdesc != NULL)
866                 return 0;
867 
868         *shash = crypto_alloc_shash(name, 0, 0);
869         if (IS_ERR(*shash)) {
870                 cifs_dbg(VFS, "could not allocate crypto %s\n", name);
871                 rc = PTR_ERR(*shash);
872                 *shash = NULL;
873                 *sdesc = NULL;
874                 return rc;
875         }
876 
877         size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
878         *sdesc = kmalloc(size, GFP_KERNEL);
879         if (*sdesc == NULL) {
880                 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
881                 crypto_free_shash(*shash);
882                 *shash = NULL;
883                 return -ENOMEM;
884         }
885 
886         (*sdesc)->shash.tfm = *shash;
887         (*sdesc)->shash.flags = 0x0;
888         return 0;
889 }
890 
891 /**
892  * cifs_free_hash - free hash and hash context together
893  *
894  * Freeing a NULL hash or context is safe.
895  */
896 void
897 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
898 {
899         kfree(*sdesc);
900         *sdesc = NULL;
901         if (*shash)
902                 crypto_free_shash(*shash);
903         *shash = NULL;
904 }
905 

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