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[~andy/linux] / fs / cifs / misc.c
1 /*
2  *   fs/cifs/misc.c
3  *
4  *   Copyright (C) International Business Machines  Corp., 2002,2008
5  *   Author(s): Steve French (sfrench@us.ibm.com)
6  *
7  *   This library is free software; you can redistribute it and/or modify
8  *   it under the terms of the GNU Lesser General Public License as published
9  *   by the Free Software Foundation; either version 2.1 of the License, or
10  *   (at your option) any later version.
11  *
12  *   This library is distributed in the hope that it will be useful,
13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
15  *   the GNU Lesser General Public License for more details.
16  *
17  *   You should have received a copy of the GNU Lesser General Public License
18  *   along with this library; if not, write to the Free Software
19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20  */
21
22 #include <linux/slab.h>
23 #include <linux/ctype.h>
24 #include <linux/mempool.h>
25 #include "cifspdu.h"
26 #include "cifsglob.h"
27 #include "cifsproto.h"
28 #include "cifs_debug.h"
29 #include "smberr.h"
30 #include "nterr.h"
31 #include "cifs_unicode.h"
32 #ifdef CONFIG_CIFS_SMB2
33 #include "smb2pdu.h"
34 #endif
35
36 extern mempool_t *cifs_sm_req_poolp;
37 extern mempool_t *cifs_req_poolp;
38
39 /* The xid serves as a useful identifier for each incoming vfs request,
40    in a similar way to the mid which is useful to track each sent smb,
41    and CurrentXid can also provide a running counter (although it
42    will eventually wrap past zero) of the total vfs operations handled
43    since the cifs fs was mounted */
44
45 unsigned int
46 _get_xid(void)
47 {
48         unsigned int xid;
49
50         spin_lock(&GlobalMid_Lock);
51         GlobalTotalActiveXid++;
52
53         /* keep high water mark for number of simultaneous ops in filesystem */
54         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
55                 GlobalMaxActiveXid = GlobalTotalActiveXid;
56         if (GlobalTotalActiveXid > 65000)
57                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
58         xid = GlobalCurrentXid++;
59         spin_unlock(&GlobalMid_Lock);
60         return xid;
61 }
62
63 void
64 _free_xid(unsigned int xid)
65 {
66         spin_lock(&GlobalMid_Lock);
67         /* if (GlobalTotalActiveXid == 0)
68                 BUG(); */
69         GlobalTotalActiveXid--;
70         spin_unlock(&GlobalMid_Lock);
71 }
72
73 struct cifs_ses *
74 sesInfoAlloc(void)
75 {
76         struct cifs_ses *ret_buf;
77
78         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
79         if (ret_buf) {
80                 atomic_inc(&sesInfoAllocCount);
81                 ret_buf->status = CifsNew;
82                 ++ret_buf->ses_count;
83                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
84                 INIT_LIST_HEAD(&ret_buf->tcon_list);
85                 mutex_init(&ret_buf->session_mutex);
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         if (buf_to_free->password) {
103                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
104                 kfree(buf_to_free->password);
105         }
106         kfree(buf_to_free->user_name);
107         kfree(buf_to_free->domainName);
108         kfree(buf_to_free->auth_key.response);
109         kfree(buf_to_free);
110 }
111
112 struct cifs_tcon *
113 tconInfoAlloc(void)
114 {
115         struct cifs_tcon *ret_buf;
116         ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
117         if (ret_buf) {
118                 atomic_inc(&tconInfoAllocCount);
119                 ret_buf->tidStatus = CifsNew;
120                 ++ret_buf->tc_count;
121                 INIT_LIST_HEAD(&ret_buf->openFileList);
122                 INIT_LIST_HEAD(&ret_buf->tcon_list);
123 #ifdef CONFIG_CIFS_STATS
124                 spin_lock_init(&ret_buf->stat_lock);
125 #endif
126         }
127         return ret_buf;
128 }
129
130 void
131 tconInfoFree(struct cifs_tcon *buf_to_free)
132 {
133         if (buf_to_free == NULL) {
134                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
135                 return;
136         }
137         atomic_dec(&tconInfoAllocCount);
138         kfree(buf_to_free->nativeFileSystem);
139         if (buf_to_free->password) {
140                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
141                 kfree(buf_to_free->password);
142         }
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         size_t buf_size = sizeof(struct smb_hdr);
151
152 #ifdef CONFIG_CIFS_SMB2
153         /*
154          * SMB2 header is bigger than CIFS one - no problems to clean some
155          * more bytes for CIFS.
156          */
157         buf_size = sizeof(struct smb2_hdr);
158 #endif
159         /*
160          * We could use negotiated size instead of max_msgsize -
161          * but it may be more efficient to always alloc same size
162          * albeit slightly larger than necessary and maxbuffersize
163          * defaults to this and can not be bigger.
164          */
165         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
166
167         /* clear the first few header bytes */
168         /* for most paths, more is cleared in header_assemble */
169         if (ret_buf) {
170                 memset(ret_buf, 0, buf_size + 3);
171                 atomic_inc(&bufAllocCount);
172 #ifdef CONFIG_CIFS_STATS2
173                 atomic_inc(&totBufAllocCount);
174 #endif /* CONFIG_CIFS_STATS2 */
175         }
176
177         return ret_buf;
178 }
179
180 void
181 cifs_buf_release(void *buf_to_free)
182 {
183         if (buf_to_free == NULL) {
184                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
185                 return;
186         }
187         mempool_free(buf_to_free, cifs_req_poolp);
188
189         atomic_dec(&bufAllocCount);
190         return;
191 }
192
193 struct smb_hdr *
194 cifs_small_buf_get(void)
195 {
196         struct smb_hdr *ret_buf = NULL;
197
198 /* We could use negotiated size instead of max_msgsize -
199    but it may be more efficient to always alloc same size
200    albeit slightly larger than necessary and maxbuffersize
201    defaults to this and can not be bigger */
202         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
203         if (ret_buf) {
204         /* No need to clear memory here, cleared in header assemble */
205         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
206                 atomic_inc(&smBufAllocCount);
207 #ifdef CONFIG_CIFS_STATS2
208                 atomic_inc(&totSmBufAllocCount);
209 #endif /* CONFIG_CIFS_STATS2 */
210
211         }
212         return ret_buf;
213 }
214
215 void
216 cifs_small_buf_release(void *buf_to_free)
217 {
218
219         if (buf_to_free == NULL) {
220                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
221                 return;
222         }
223         mempool_free(buf_to_free, cifs_sm_req_poolp);
224
225         atomic_dec(&smBufAllocCount);
226         return;
227 }
228
229 /* NB: MID can not be set if treeCon not passed in, in that
230    case it is responsbility of caller to set the mid */
231 void
232 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
233                 const struct cifs_tcon *treeCon, int word_count
234                 /* length of fixed section (word count) in two byte units  */)
235 {
236         char *temp = (char *) buffer;
237
238         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
239
240         buffer->smb_buf_length = cpu_to_be32(
241             (2 * word_count) + sizeof(struct smb_hdr) -
242             4 /*  RFC 1001 length field does not count */  +
243             2 /* for bcc field itself */) ;
244
245         buffer->Protocol[0] = 0xFF;
246         buffer->Protocol[1] = 'S';
247         buffer->Protocol[2] = 'M';
248         buffer->Protocol[3] = 'B';
249         buffer->Command = smb_command;
250         buffer->Flags = 0x00;   /* case sensitive */
251         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
252         buffer->Pid = cpu_to_le16((__u16)current->tgid);
253         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
254         if (treeCon) {
255                 buffer->Tid = treeCon->tid;
256                 if (treeCon->ses) {
257                         if (treeCon->ses->capabilities & CAP_UNICODE)
258                                 buffer->Flags2 |= SMBFLG2_UNICODE;
259                         if (treeCon->ses->capabilities & CAP_STATUS32)
260                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
261
262                         /* Uid is not converted */
263                         buffer->Uid = treeCon->ses->Suid;
264                         buffer->Mid = get_next_mid(treeCon->ses->server);
265                 }
266                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
267                         buffer->Flags2 |= SMBFLG2_DFS;
268                 if (treeCon->nocase)
269                         buffer->Flags  |= SMBFLG_CASELESS;
270                 if ((treeCon->ses) && (treeCon->ses->server))
271                         if (treeCon->ses->server->sign)
272                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
273         }
274
275 /*  endian conversion of flags is now done just before sending */
276         buffer->WordCount = (char) word_count;
277         return;
278 }
279
280 static int
281 check_smb_hdr(struct smb_hdr *smb)
282 {
283         /* does it have the right SMB "signature" ? */
284         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
285                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
286                          *(unsigned int *)smb->Protocol);
287                 return 1;
288         }
289
290         /* if it's a response then accept */
291         if (smb->Flags & SMBFLG_RESPONSE)
292                 return 0;
293
294         /* only one valid case where server sends us request */
295         if (smb->Command == SMB_COM_LOCKING_ANDX)
296                 return 0;
297
298         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
299                  get_mid(smb));
300         return 1;
301 }
302
303 int
304 checkSMB(char *buf, unsigned int total_read)
305 {
306         struct smb_hdr *smb = (struct smb_hdr *)buf;
307         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
308         __u32 clc_len;  /* calculated length */
309         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
310                  total_read, rfclen);
311
312         /* is this frame too small to even get to a BCC? */
313         if (total_read < 2 + sizeof(struct smb_hdr)) {
314                 if ((total_read >= sizeof(struct smb_hdr) - 1)
315                             && (smb->Status.CifsError != 0)) {
316                         /* it's an error return */
317                         smb->WordCount = 0;
318                         /* some error cases do not return wct and bcc */
319                         return 0;
320                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
321                                 (smb->WordCount == 0)) {
322                         char *tmp = (char *)smb;
323                         /* Need to work around a bug in two servers here */
324                         /* First, check if the part of bcc they sent was zero */
325                         if (tmp[sizeof(struct smb_hdr)] == 0) {
326                                 /* some servers return only half of bcc
327                                  * on simple responses (wct, bcc both zero)
328                                  * in particular have seen this on
329                                  * ulogoffX and FindClose. This leaves
330                                  * one byte of bcc potentially unitialized
331                                  */
332                                 /* zero rest of bcc */
333                                 tmp[sizeof(struct smb_hdr)+1] = 0;
334                                 return 0;
335                         }
336                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
337                 } else {
338                         cifs_dbg(VFS, "Length less than smb header size\n");
339                 }
340                 return -EIO;
341         }
342
343         /* otherwise, there is enough to get to the BCC */
344         if (check_smb_hdr(smb))
345                 return -EIO;
346         clc_len = smbCalcSize(smb);
347
348         if (4 + rfclen != total_read) {
349                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
350                          rfclen);
351                 return -EIO;
352         }
353
354         if (4 + rfclen != clc_len) {
355                 __u16 mid = get_mid(smb);
356                 /* check if bcc wrapped around for large read responses */
357                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
358                         /* check if lengths match mod 64K */
359                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
360                                 return 0; /* bcc wrapped */
361                 }
362                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
363                          clc_len, 4 + rfclen, mid);
364
365                 if (4 + rfclen < clc_len) {
366                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
367                                  rfclen, mid);
368                         return -EIO;
369                 } else if (rfclen > clc_len + 512) {
370                         /*
371                          * Some servers (Windows XP in particular) send more
372                          * data than the lengths in the SMB packet would
373                          * indicate on certain calls (byte range locks and
374                          * trans2 find first calls in particular). While the
375                          * client can handle such a frame by ignoring the
376                          * trailing data, we choose limit the amount of extra
377                          * data to 512 bytes.
378                          */
379                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
380                                  rfclen, mid);
381                         return -EIO;
382                 }
383         }
384         return 0;
385 }
386
387 bool
388 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
389 {
390         struct smb_hdr *buf = (struct smb_hdr *)buffer;
391         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
392         struct list_head *tmp, *tmp1, *tmp2;
393         struct cifs_ses *ses;
394         struct cifs_tcon *tcon;
395         struct cifsInodeInfo *pCifsInode;
396         struct cifsFileInfo *netfile;
397
398         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
399         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
400            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
401                 struct smb_com_transaction_change_notify_rsp *pSMBr =
402                         (struct smb_com_transaction_change_notify_rsp *)buf;
403                 struct file_notify_information *pnotify;
404                 __u32 data_offset = 0;
405                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
406                         data_offset = le32_to_cpu(pSMBr->DataOffset);
407
408                         pnotify = (struct file_notify_information *)
409                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
410                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
411                                  pnotify->FileName, pnotify->Action);
412                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
413                                 sizeof(struct smb_hdr)+60); */
414                         return true;
415                 }
416                 if (pSMBr->hdr.Status.CifsError) {
417                         cifs_dbg(FYI, "notify err 0x%d\n",
418                                  pSMBr->hdr.Status.CifsError);
419                         return true;
420                 }
421                 return false;
422         }
423         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
424                 return false;
425         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
426                 /* no sense logging error on invalid handle on oplock
427                    break - harmless race between close request and oplock
428                    break response is expected from time to time writing out
429                    large dirty files cached on the client */
430                 if ((NT_STATUS_INVALID_HANDLE) ==
431                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
432                         cifs_dbg(FYI, "invalid handle on oplock break\n");
433                         return true;
434                 } else if (ERRbadfid ==
435                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
436                         return true;
437                 } else {
438                         return false; /* on valid oplock brk we get "request" */
439                 }
440         }
441         if (pSMB->hdr.WordCount != 8)
442                 return false;
443
444         cifs_dbg(FYI, "oplock type 0x%d level 0x%d\n",
445                  pSMB->LockType, pSMB->OplockLevel);
446         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
447                 return false;
448
449         /* look up tcon based on tid & uid */
450         spin_lock(&cifs_tcp_ses_lock);
451         list_for_each(tmp, &srv->smb_ses_list) {
452                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
453                 list_for_each(tmp1, &ses->tcon_list) {
454                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
455                         if (tcon->tid != buf->Tid)
456                                 continue;
457
458                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
459                         spin_lock(&cifs_file_list_lock);
460                         list_for_each(tmp2, &tcon->openFileList) {
461                                 netfile = list_entry(tmp2, struct cifsFileInfo,
462                                                      tlist);
463                                 if (pSMB->Fid != netfile->fid.netfid)
464                                         continue;
465
466                                 cifs_dbg(FYI, "file id match, oplock break\n");
467                                 pCifsInode = CIFS_I(netfile->dentry->d_inode);
468
469                                 cifs_set_oplock_level(pCifsInode,
470                                         pSMB->OplockLevel ? OPLOCK_READ : 0);
471                                 queue_work(cifsiod_wq,
472                                            &netfile->oplock_break);
473                                 netfile->oplock_break_cancelled = false;
474
475                                 spin_unlock(&cifs_file_list_lock);
476                                 spin_unlock(&cifs_tcp_ses_lock);
477                                 return true;
478                         }
479                         spin_unlock(&cifs_file_list_lock);
480                         spin_unlock(&cifs_tcp_ses_lock);
481                         cifs_dbg(FYI, "No matching file for oplock break\n");
482                         return true;
483                 }
484         }
485         spin_unlock(&cifs_tcp_ses_lock);
486         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
487         return true;
488 }
489
490 void
491 dump_smb(void *buf, int smb_buf_length)
492 {
493         int i, j;
494         char debug_line[17];
495         unsigned char *buffer = buf;
496
497         if (traceSMB == 0)
498                 return;
499
500         for (i = 0, j = 0; i < smb_buf_length; i++, j++) {
501                 if (i % 8 == 0) {
502                         /* have reached the beginning of line */
503                         printk(KERN_DEBUG "| ");
504                         j = 0;
505                 }
506                 printk("%0#4x ", buffer[i]);
507                 debug_line[2 * j] = ' ';
508                 if (isprint(buffer[i]))
509                         debug_line[1 + (2 * j)] = buffer[i];
510                 else
511                         debug_line[1 + (2 * j)] = '_';
512
513                 if (i % 8 == 7) {
514                         /* reached end of line, time to print ascii */
515                         debug_line[16] = 0;
516                         printk(" | %s\n", debug_line);
517                 }
518         }
519         for (; j < 8; j++) {
520                 printk("     ");
521                 debug_line[2 * j] = ' ';
522                 debug_line[1 + (2 * j)] = ' ';
523         }
524         printk(" | %s\n", debug_line);
525         return;
526 }
527
528 void
529 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
530 {
531         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
532                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
533                 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",
534                          cifs_sb_master_tcon(cifs_sb)->treeName);
535         }
536 }
537
538 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
539 {
540         oplock &= 0xF;
541
542         if (oplock == OPLOCK_EXCLUSIVE) {
543                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
544                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
545                          &cinode->vfs_inode);
546         } else if (oplock == OPLOCK_READ) {
547                 cinode->oplock = CIFS_CACHE_READ_FLG;
548                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
549                          &cinode->vfs_inode);
550         } else
551                 cinode->oplock = 0;
552 }
553
554 bool
555 backup_cred(struct cifs_sb_info *cifs_sb)
556 {
557         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
558                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
559                         return true;
560         }
561         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
562                 if (in_group_p(cifs_sb->mnt_backupgid))
563                         return true;
564         }
565
566         return false;
567 }
568
569 void
570 cifs_del_pending_open(struct cifs_pending_open *open)
571 {
572         spin_lock(&cifs_file_list_lock);
573         list_del(&open->olist);
574         spin_unlock(&cifs_file_list_lock);
575 }
576
577 void
578 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
579                              struct cifs_pending_open *open)
580 {
581 #ifdef CONFIG_CIFS_SMB2
582         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
583 #endif
584         open->oplock = CIFS_OPLOCK_NO_CHANGE;
585         open->tlink = tlink;
586         fid->pending_open = open;
587         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
588 }
589
590 void
591 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
592                       struct cifs_pending_open *open)
593 {
594         spin_lock(&cifs_file_list_lock);
595         cifs_add_pending_open_locked(fid, tlink, open);
596         spin_unlock(&cifs_file_list_lock);
597 }