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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 #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         kzfree(buf_to_free->password);
107         kfree(buf_to_free->user_name);
108         kfree(buf_to_free->domainName);
109         kzfree(buf_to_free->auth_key.response);
110         kfree(buf_to_free->iface_list);
111         kzfree(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         kzfree(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         }
357 
358         /* otherwise, there is enough to get to the BCC */
359         if (check_smb_hdr(smb))
360                 return -EIO;
361         clc_len = smbCalcSize(smb, server);
362 
363         if (4 + rfclen != total_read) {
364                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
365                          rfclen);
366                 return -EIO;
367         }
368 
369         if (4 + rfclen != clc_len) {
370                 __u16 mid = get_mid(smb);
371                 /* check if bcc wrapped around for large read responses */
372                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
373                         /* check if lengths match mod 64K */
374                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
375                                 return 0; /* bcc wrapped */
376                 }
377                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
378                          clc_len, 4 + rfclen, mid);
379 
380                 if (4 + rfclen < clc_len) {
381                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
382                                  rfclen, mid);
383                         return -EIO;
384                 } else if (rfclen > clc_len + 512) {
385                         /*
386                          * Some servers (Windows XP in particular) send more
387                          * data than the lengths in the SMB packet would
388                          * indicate on certain calls (byte range locks and
389                          * trans2 find first calls in particular). While the
390                          * client can handle such a frame by ignoring the
391                          * trailing data, we choose limit the amount of extra
392                          * data to 512 bytes.
393                          */
394                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
395                                  rfclen, mid);
396                         return -EIO;
397                 }
398         }
399         return 0;
400 }
401 
402 bool
403 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
404 {
405         struct smb_hdr *buf = (struct smb_hdr *)buffer;
406         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
407         struct list_head *tmp, *tmp1, *tmp2;
408         struct cifs_ses *ses;
409         struct cifs_tcon *tcon;
410         struct cifsInodeInfo *pCifsInode;
411         struct cifsFileInfo *netfile;
412 
413         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
414         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
415            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
416                 struct smb_com_transaction_change_notify_rsp *pSMBr =
417                         (struct smb_com_transaction_change_notify_rsp *)buf;
418                 struct file_notify_information *pnotify;
419                 __u32 data_offset = 0;
420                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
421 
422                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
423                         data_offset = le32_to_cpu(pSMBr->DataOffset);
424 
425                         if (data_offset >
426                             len - sizeof(struct file_notify_information)) {
427                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
428                                          data_offset);
429                                 return true;
430                         }
431                         pnotify = (struct file_notify_information *)
432                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
433                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
434                                  pnotify->FileName, pnotify->Action);
435                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
436                                 sizeof(struct smb_hdr)+60); */
437                         return true;
438                 }
439                 if (pSMBr->hdr.Status.CifsError) {
440                         cifs_dbg(FYI, "notify err 0x%x\n",
441                                  pSMBr->hdr.Status.CifsError);
442                         return true;
443                 }
444                 return false;
445         }
446         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
447                 return false;
448         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
449                 /* no sense logging error on invalid handle on oplock
450                    break - harmless race between close request and oplock
451                    break response is expected from time to time writing out
452                    large dirty files cached on the client */
453                 if ((NT_STATUS_INVALID_HANDLE) ==
454                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
455                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
456                         return true;
457                 } else if (ERRbadfid ==
458                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
459                         return true;
460                 } else {
461                         return false; /* on valid oplock brk we get "request" */
462                 }
463         }
464         if (pSMB->hdr.WordCount != 8)
465                 return false;
466 
467         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
468                  pSMB->LockType, pSMB->OplockLevel);
469         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
470                 return false;
471 
472         /* look up tcon based on tid & uid */
473         spin_lock(&cifs_tcp_ses_lock);
474         list_for_each(tmp, &srv->smb_ses_list) {
475                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
476                 list_for_each(tmp1, &ses->tcon_list) {
477                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
478                         if (tcon->tid != buf->Tid)
479                                 continue;
480 
481                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
482                         spin_lock(&tcon->open_file_lock);
483                         list_for_each(tmp2, &tcon->openFileList) {
484                                 netfile = list_entry(tmp2, struct cifsFileInfo,
485                                                      tlist);
486                                 if (pSMB->Fid != netfile->fid.netfid)
487                                         continue;
488 
489                                 cifs_dbg(FYI, "file id match, oplock break\n");
490                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
491 
492                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
493                                         &pCifsInode->flags);
494 
495                                 netfile->oplock_epoch = 0;
496                                 netfile->oplock_level = pSMB->OplockLevel;
497                                 netfile->oplock_break_cancelled = false;
498                                 cifs_queue_oplock_break(netfile);
499 
500                                 spin_unlock(&tcon->open_file_lock);
501                                 spin_unlock(&cifs_tcp_ses_lock);
502                                 return true;
503                         }
504                         spin_unlock(&tcon->open_file_lock);
505                         spin_unlock(&cifs_tcp_ses_lock);
506                         cifs_dbg(FYI, "No matching file for oplock break\n");
507                         return true;
508                 }
509         }
510         spin_unlock(&cifs_tcp_ses_lock);
511         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
512         return true;
513 }
514 
515 void
516 dump_smb(void *buf, int smb_buf_length)
517 {
518         if (traceSMB == 0)
519                 return;
520 
521         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
522                        smb_buf_length, true);
523 }
524 
525 void
526 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
527 {
528         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
529                 struct cifs_tcon *tcon = NULL;
530 
531                 if (cifs_sb->master_tlink)
532                         tcon = cifs_sb_master_tcon(cifs_sb);
533 
534                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
535                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
536                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
537                          tcon ? tcon->treeName : "new server");
538                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
539                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
540 
541         }
542 }
543 
544 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
545 {
546         oplock &= 0xF;
547 
548         if (oplock == OPLOCK_EXCLUSIVE) {
549                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
550                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
551                          &cinode->vfs_inode);
552         } else if (oplock == OPLOCK_READ) {
553                 cinode->oplock = CIFS_CACHE_READ_FLG;
554                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
555                          &cinode->vfs_inode);
556         } else
557                 cinode->oplock = 0;
558 }
559 
560 /*
561  * We wait for oplock breaks to be processed before we attempt to perform
562  * writes.
563  */
564 int cifs_get_writer(struct cifsInodeInfo *cinode)
565 {
566         int rc;
567 
568 start:
569         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
570                          TASK_KILLABLE);
571         if (rc)
572                 return rc;
573 
574         spin_lock(&cinode->writers_lock);
575         if (!cinode->writers)
576                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
577         cinode->writers++;
578         /* Check to see if we have started servicing an oplock break */
579         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
580                 cinode->writers--;
581                 if (cinode->writers == 0) {
582                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
583                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
584                 }
585                 spin_unlock(&cinode->writers_lock);
586                 goto start;
587         }
588         spin_unlock(&cinode->writers_lock);
589         return 0;
590 }
591 
592 void cifs_put_writer(struct cifsInodeInfo *cinode)
593 {
594         spin_lock(&cinode->writers_lock);
595         cinode->writers--;
596         if (cinode->writers == 0) {
597                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
598                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
599         }
600         spin_unlock(&cinode->writers_lock);
601 }
602 
603 /**
604  * cifs_queue_oplock_break - queue the oplock break handler for cfile
605  *
606  * This function is called from the demultiplex thread when it
607  * receives an oplock break for @cfile.
608  *
609  * Assumes the tcon->open_file_lock is held.
610  * Assumes cfile->file_info_lock is NOT held.
611  */
612 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
613 {
614         /*
615          * Bump the handle refcount now while we hold the
616          * open_file_lock to enforce the validity of it for the oplock
617          * break handler. The matching put is done at the end of the
618          * handler.
619          */
620         cifsFileInfo_get(cfile);
621 
622         queue_work(cifsoplockd_wq, &cfile->oplock_break);
623 }
624 
625 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
626 {
627         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
628         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
629 }
630 
631 bool
632 backup_cred(struct cifs_sb_info *cifs_sb)
633 {
634         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
635                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
636                         return true;
637         }
638         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
639                 if (in_group_p(cifs_sb->mnt_backupgid))
640                         return true;
641         }
642 
643         return false;
644 }
645 
646 void
647 cifs_del_pending_open(struct cifs_pending_open *open)
648 {
649         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
650         list_del(&open->olist);
651         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
652 }
653 
654 void
655 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
656                              struct cifs_pending_open *open)
657 {
658         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
659         open->oplock = CIFS_OPLOCK_NO_CHANGE;
660         open->tlink = tlink;
661         fid->pending_open = open;
662         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
663 }
664 
665 void
666 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
667                       struct cifs_pending_open *open)
668 {
669         spin_lock(&tlink_tcon(tlink)->open_file_lock);
670         cifs_add_pending_open_locked(fid, tlink, open);
671         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
672 }
673 
674 /* parses DFS refferal V3 structure
675  * caller is responsible for freeing target_nodes
676  * returns:
677  * - on success - 0
678  * - on failure - errno
679  */
680 int
681 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
682                     unsigned int *num_of_nodes,
683                     struct dfs_info3_param **target_nodes,
684                     const struct nls_table *nls_codepage, int remap,
685                     const char *searchName, bool is_unicode)
686 {
687         int i, rc = 0;
688         char *data_end;
689         struct dfs_referral_level_3 *ref;
690 
691         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
692 
693         if (*num_of_nodes < 1) {
694                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
695                          *num_of_nodes);
696                 rc = -EINVAL;
697                 goto parse_DFS_referrals_exit;
698         }
699 
700         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
701         if (ref->VersionNumber != cpu_to_le16(3)) {
702                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
703                          le16_to_cpu(ref->VersionNumber));
704                 rc = -EINVAL;
705                 goto parse_DFS_referrals_exit;
706         }
707 
708         /* get the upper boundary of the resp buffer */
709         data_end = (char *)rsp + rsp_size;
710 
711         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
712                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
713 
714         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
715                                 GFP_KERNEL);
716         if (*target_nodes == NULL) {
717                 rc = -ENOMEM;
718                 goto parse_DFS_referrals_exit;
719         }
720 
721         /* collect necessary data from referrals */
722         for (i = 0; i < *num_of_nodes; i++) {
723                 char *temp;
724                 int max_len;
725                 struct dfs_info3_param *node = (*target_nodes)+i;
726 
727                 node->flags = le32_to_cpu(rsp->DFSFlags);
728                 if (is_unicode) {
729                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
730                                                 GFP_KERNEL);
731                         if (tmp == NULL) {
732                                 rc = -ENOMEM;
733                                 goto parse_DFS_referrals_exit;
734                         }
735                         cifsConvertToUTF16((__le16 *) tmp, searchName,
736                                            PATH_MAX, nls_codepage, remap);
737                         node->path_consumed = cifs_utf16_bytes(tmp,
738                                         le16_to_cpu(rsp->PathConsumed),
739                                         nls_codepage);
740                         kfree(tmp);
741                 } else
742                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
743 
744                 node->server_type = le16_to_cpu(ref->ServerType);
745                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
746 
747                 /* copy DfsPath */
748                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
749                 max_len = data_end - temp;
750                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
751                                                 is_unicode, nls_codepage);
752                 if (!node->path_name) {
753                         rc = -ENOMEM;
754                         goto parse_DFS_referrals_exit;
755                 }
756 
757                 /* copy link target UNC */
758                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
759                 max_len = data_end - temp;
760                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
761                                                 is_unicode, nls_codepage);
762                 if (!node->node_name) {
763                         rc = -ENOMEM;
764                         goto parse_DFS_referrals_exit;
765                 }
766 
767                 node->ttl = le32_to_cpu(ref->TimeToLive);
768 
769                 ref++;
770         }
771 
772 parse_DFS_referrals_exit:
773         if (rc) {
774                 free_dfs_info_array(*target_nodes, *num_of_nodes);
775                 *target_nodes = NULL;
776                 *num_of_nodes = 0;
777         }
778         return rc;
779 }
780 
781 struct cifs_aio_ctx *
782 cifs_aio_ctx_alloc(void)
783 {
784         struct cifs_aio_ctx *ctx;
785 
786         /*
787          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
788          * to false so that we know when we have to unreference pages within
789          * cifs_aio_ctx_release()
790          */
791         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
792         if (!ctx)
793                 return NULL;
794 
795         INIT_LIST_HEAD(&ctx->list);
796         mutex_init(&ctx->aio_mutex);
797         init_completion(&ctx->done);
798         kref_init(&ctx->refcount);
799         return ctx;
800 }
801 
802 void
803 cifs_aio_ctx_release(struct kref *refcount)
804 {
805         struct cifs_aio_ctx *ctx = container_of(refcount,
806                                         struct cifs_aio_ctx, refcount);
807 
808         cifsFileInfo_put(ctx->cfile);
809 
810         /*
811          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
812          * which means that iov_iter_get_pages() was a success and thus that
813          * we have taken reference on pages.
814          */
815         if (ctx->bv) {
816                 unsigned i;
817 
818                 for (i = 0; i < ctx->npages; i++) {
819                         if (ctx->should_dirty)
820                                 set_page_dirty(ctx->bv[i].bv_page);
821                         put_page(ctx->bv[i].bv_page);
822                 }
823                 kvfree(ctx->bv);
824         }
825 
826         kfree(ctx);
827 }
828 
829 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
830 
831 int
832 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
833 {
834         ssize_t rc;
835         unsigned int cur_npages;
836         unsigned int npages = 0;
837         unsigned int i;
838         size_t len;
839         size_t count = iov_iter_count(iter);
840         unsigned int saved_len;
841         size_t start;
842         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
843         struct page **pages = NULL;
844         struct bio_vec *bv = NULL;
845 
846         if (iov_iter_is_kvec(iter)) {
847                 memcpy(&ctx->iter, iter, sizeof(*iter));
848                 ctx->len = count;
849                 iov_iter_advance(iter, count);
850                 return 0;
851         }
852 
853         if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
854                 bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
855 
856         if (!bv) {
857                 bv = vmalloc(array_size(max_pages, sizeof(*bv)));
858                 if (!bv)
859                         return -ENOMEM;
860         }
861 
862         if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
863                 pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
864 
865         if (!pages) {
866                 pages = vmalloc(array_size(max_pages, sizeof(*pages)));
867                 if (!pages) {
868                         kvfree(bv);
869                         return -ENOMEM;
870                 }
871         }
872 
873         saved_len = count;
874 
875         while (count && npages < max_pages) {
876                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
877                 if (rc < 0) {
878                         cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc);
879                         break;
880                 }
881 
882                 if (rc > count) {
883                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
884                                  count);
885                         break;
886                 }
887 
888                 iov_iter_advance(iter, rc);
889                 count -= rc;
890                 rc += start;
891                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
892 
893                 if (npages + cur_npages > max_pages) {
894                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
895                                  npages + cur_npages, max_pages);
896                         break;
897                 }
898 
899                 for (i = 0; i < cur_npages; i++) {
900                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
901                         bv[npages + i].bv_page = pages[i];
902                         bv[npages + i].bv_offset = start;
903                         bv[npages + i].bv_len = len - start;
904                         rc -= len;
905                         start = 0;
906                 }
907 
908                 npages += cur_npages;
909         }
910 
911         kvfree(pages);
912         ctx->bv = bv;
913         ctx->len = saved_len - count;
914         ctx->npages = npages;
915         iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
916         return 0;
917 }
918 
919 /**
920  * cifs_alloc_hash - allocate hash and hash context together
921  *
922  * The caller has to make sure @sdesc is initialized to either NULL or
923  * a valid context. Both can be freed via cifs_free_hash().
924  */
925 int
926 cifs_alloc_hash(const char *name,
927                 struct crypto_shash **shash, struct sdesc **sdesc)
928 {
929         int rc = 0;
930         size_t size;
931 
932         if (*sdesc != NULL)
933                 return 0;
934 
935         *shash = crypto_alloc_shash(name, 0, 0);
936         if (IS_ERR(*shash)) {
937                 cifs_dbg(VFS, "Could not allocate crypto %s\n", name);
938                 rc = PTR_ERR(*shash);
939                 *shash = NULL;
940                 *sdesc = NULL;
941                 return rc;
942         }
943 
944         size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
945         *sdesc = kmalloc(size, GFP_KERNEL);
946         if (*sdesc == NULL) {
947                 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
948                 crypto_free_shash(*shash);
949                 *shash = NULL;
950                 return -ENOMEM;
951         }
952 
953         (*sdesc)->shash.tfm = *shash;
954         return 0;
955 }
956 
957 /**
958  * cifs_free_hash - free hash and hash context together
959  *
960  * Freeing a NULL hash or context is safe.
961  */
962 void
963 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
964 {
965         kfree(*sdesc);
966         *sdesc = NULL;
967         if (*shash)
968                 crypto_free_shash(*shash);
969         *shash = NULL;
970 }
971 
972 /**
973  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
974  * Input: rqst - a smb_rqst, page - a page index for rqst
975  * Output: *len - the length for this page, *offset - the offset for this page
976  */
977 void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
978                                 unsigned int *len, unsigned int *offset)
979 {
980         *len = rqst->rq_pagesz;
981         *offset = (page == 0) ? rqst->rq_offset : 0;
982 
983         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
984                 *len = rqst->rq_tailsz;
985         else if (page == 0)
986                 *len = rqst->rq_pagesz - rqst->rq_offset;
987 }
988 
989 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
990 {
991         const char *end;
992 
993         /* skip initial slashes */
994         while (*unc && (*unc == '\\' || *unc == '/'))
995                 unc++;
996 
997         end = unc;
998 
999         while (*end && !(*end == '\\' || *end == '/'))
1000                 end++;
1001 
1002         *h = unc;
1003         *len = end - unc;
1004 }
1005 
1006 /**
1007  * copy_path_name - copy src path to dst, possibly truncating
1008  *
1009  * returns number of bytes written (including trailing nul)
1010  */
1011 int copy_path_name(char *dst, const char *src)
1012 {
1013         int name_len;
1014 
1015         /*
1016          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1017          * will truncate and strlen(dst) will be PATH_MAX-1
1018          */
1019         name_len = strscpy(dst, src, PATH_MAX);
1020         if (WARN_ON_ONCE(name_len < 0))
1021                 name_len = PATH_MAX-1;
1022 
1023         /* we count the trailing nul */
1024         name_len++;
1025         return name_len;
1026 }
1027 
1028 struct super_cb_data {
1029         void *data;
1030         struct super_block *sb;
1031 };
1032 
1033 static void tcp_super_cb(struct super_block *sb, void *arg)
1034 {
1035         struct super_cb_data *sd = arg;
1036         struct TCP_Server_Info *server = sd->data;
1037         struct cifs_sb_info *cifs_sb;
1038         struct cifs_tcon *tcon;
1039 
1040         if (sd->sb)
1041                 return;
1042 
1043         cifs_sb = CIFS_SB(sb);
1044         tcon = cifs_sb_master_tcon(cifs_sb);
1045         if (tcon->ses->server == server)
1046                 sd->sb = sb;
1047 }
1048 
1049 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1050                                             void *data)
1051 {
1052         struct super_cb_data sd = {
1053                 .data = data,
1054                 .sb = NULL,
1055         };
1056 
1057         iterate_supers_type(&cifs_fs_type, f, &sd);
1058 
1059         if (!sd.sb)
1060                 return ERR_PTR(-EINVAL);
1061         /*
1062          * Grab an active reference in order to prevent automounts (DFS links)
1063          * of expiring and then freeing up our cifs superblock pointer while
1064          * we're doing failover.
1065          */
1066         cifs_sb_active(sd.sb);
1067         return sd.sb;
1068 }
1069 
1070 static void __cifs_put_super(struct super_block *sb)
1071 {
1072         if (!IS_ERR_OR_NULL(sb))
1073                 cifs_sb_deactive(sb);
1074 }
1075 
1076 struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server)
1077 {
1078         return __cifs_get_super(tcp_super_cb, server);
1079 }
1080 
1081 void cifs_put_tcp_super(struct super_block *sb)
1082 {
1083         __cifs_put_super(sb);
1084 }
1085 
1086 #ifdef CONFIG_CIFS_DFS_UPCALL
1087 int match_target_ip(struct TCP_Server_Info *server,
1088                     const char *share, size_t share_len,
1089                     bool *result)
1090 {
1091         int rc;
1092         char *target, *tip = NULL;
1093         struct sockaddr tipaddr;
1094 
1095         *result = false;
1096 
1097         target = kzalloc(share_len + 3, GFP_KERNEL);
1098         if (!target) {
1099                 rc = -ENOMEM;
1100                 goto out;
1101         }
1102 
1103         scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1104 
1105         cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1106 
1107         rc = dns_resolve_server_name_to_ip(target, &tip);
1108         if (rc < 0)
1109                 goto out;
1110 
1111         cifs_dbg(FYI, "%s: target ip: %s\n", __func__, tip);
1112 
1113         if (!cifs_convert_address(&tipaddr, tip, strlen(tip))) {
1114                 cifs_dbg(VFS, "%s: failed to convert target ip address\n",
1115                          __func__);
1116                 rc = -EINVAL;
1117                 goto out;
1118         }
1119 
1120         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr,
1121                                     &tipaddr);
1122         cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1123         rc = 0;
1124 
1125 out:
1126         kfree(target);
1127         kfree(tip);
1128 
1129         return rc;
1130 }
1131 
1132 static void tcon_super_cb(struct super_block *sb, void *arg)
1133 {
1134         struct super_cb_data *sd = arg;
1135         struct cifs_tcon *tcon = sd->data;
1136         struct cifs_sb_info *cifs_sb;
1137 
1138         if (sd->sb)
1139                 return;
1140 
1141         cifs_sb = CIFS_SB(sb);
1142         if (tcon->dfs_path && cifs_sb->origin_fullpath &&
1143             !strcasecmp(tcon->dfs_path, cifs_sb->origin_fullpath))
1144                 sd->sb = sb;
1145 }
1146 
1147 static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
1148 {
1149         return __cifs_get_super(tcon_super_cb, tcon);
1150 }
1151 
1152 static inline void cifs_put_tcon_super(struct super_block *sb)
1153 {
1154         __cifs_put_super(sb);
1155 }
1156 #else
1157 static inline struct super_block *cifs_get_tcon_super(struct cifs_tcon *tcon)
1158 {
1159         return ERR_PTR(-EOPNOTSUPP);
1160 }
1161 
1162 static inline void cifs_put_tcon_super(struct super_block *sb)
1163 {
1164 }
1165 #endif
1166 
1167 int update_super_prepath(struct cifs_tcon *tcon, const char *prefix,
1168                          size_t prefix_len)
1169 {
1170         struct super_block *sb;
1171         struct cifs_sb_info *cifs_sb;
1172         int rc = 0;
1173 
1174         sb = cifs_get_tcon_super(tcon);
1175         if (IS_ERR(sb))
1176                 return PTR_ERR(sb);
1177 
1178         cifs_sb = CIFS_SB(sb);
1179 
1180         kfree(cifs_sb->prepath);
1181 
1182         if (*prefix && prefix_len) {
1183                 cifs_sb->prepath = kstrndup(prefix, prefix_len, GFP_ATOMIC);
1184                 if (!cifs_sb->prepath) {
1185                         rc = -ENOMEM;
1186                         goto out;
1187                 }
1188 
1189                 convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1190         } else
1191                 cifs_sb->prepath = NULL;
1192 
1193         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1194 
1195 out:
1196         cifs_put_tcon_super(sb);
1197         return rc;
1198 }
1199 

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