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Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux
[mirror_ubuntu-zesty-kernel.git] / fs / cifs / link.c
1 /*
2 * fs/cifs/link.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 #include <linux/fs.h>
22 #include <linux/stat.h>
23 #include <linux/slab.h>
24 #include <linux/namei.h>
25 #include "cifsfs.h"
26 #include "cifspdu.h"
27 #include "cifsglob.h"
28 #include "cifsproto.h"
29 #include "cifs_debug.h"
30 #include "cifs_fs_sb.h"
31
32 #define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
33 #define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
34 #define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
35 #define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
36 #define CIFS_MF_SYMLINK_FILE_SIZE \
37 (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
38
39 #define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
40 #define CIFS_MF_SYMLINK_MD5_FORMAT \
41 "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
42 #define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
43 md5_hash[0], md5_hash[1], md5_hash[2], md5_hash[3], \
44 md5_hash[4], md5_hash[5], md5_hash[6], md5_hash[7], \
45 md5_hash[8], md5_hash[9], md5_hash[10], md5_hash[11],\
46 md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
47
48 static int
49 symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
50 {
51 int rc;
52 unsigned int size;
53 struct crypto_shash *md5;
54 struct sdesc *sdescmd5;
55
56 md5 = crypto_alloc_shash("md5", 0, 0);
57 if (IS_ERR(md5)) {
58 rc = PTR_ERR(md5);
59 cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
60 __func__, rc);
61 return rc;
62 }
63 size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
64 sdescmd5 = kmalloc(size, GFP_KERNEL);
65 if (!sdescmd5) {
66 rc = -ENOMEM;
67 goto symlink_hash_err;
68 }
69 sdescmd5->shash.tfm = md5;
70 sdescmd5->shash.flags = 0x0;
71
72 rc = crypto_shash_init(&sdescmd5->shash);
73 if (rc) {
74 cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
75 goto symlink_hash_err;
76 }
77 rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
78 if (rc) {
79 cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
80 goto symlink_hash_err;
81 }
82 rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
83 if (rc)
84 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
85
86 symlink_hash_err:
87 crypto_free_shash(md5);
88 kfree(sdescmd5);
89
90 return rc;
91 }
92
93 static int
94 CIFSParseMFSymlink(const u8 *buf,
95 unsigned int buf_len,
96 unsigned int *_link_len,
97 char **_link_str)
98 {
99 int rc;
100 unsigned int link_len;
101 const char *md5_str1;
102 const char *link_str;
103 u8 md5_hash[16];
104 char md5_str2[34];
105
106 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
107 return -EINVAL;
108
109 md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
110 link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
111
112 rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
113 if (rc != 1)
114 return -EINVAL;
115
116 rc = symlink_hash(link_len, link_str, md5_hash);
117 if (rc) {
118 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
119 return rc;
120 }
121
122 snprintf(md5_str2, sizeof(md5_str2),
123 CIFS_MF_SYMLINK_MD5_FORMAT,
124 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
125
126 if (strncmp(md5_str1, md5_str2, 17) != 0)
127 return -EINVAL;
128
129 if (_link_str) {
130 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
131 if (!*_link_str)
132 return -ENOMEM;
133 }
134
135 *_link_len = link_len;
136 return 0;
137 }
138
139 static int
140 CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
141 {
142 int rc;
143 unsigned int link_len;
144 unsigned int ofs;
145 u8 md5_hash[16];
146
147 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
148 return -EINVAL;
149
150 link_len = strlen(link_str);
151
152 if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
153 return -ENAMETOOLONG;
154
155 rc = symlink_hash(link_len, link_str, md5_hash);
156 if (rc) {
157 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
158 return rc;
159 }
160
161 snprintf(buf, buf_len,
162 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
163 link_len,
164 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
165
166 ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
167 memcpy(buf + ofs, link_str, link_len);
168
169 ofs += link_len;
170 if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
171 buf[ofs] = '\n';
172 ofs++;
173 }
174
175 while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
176 buf[ofs] = ' ';
177 ofs++;
178 }
179
180 return 0;
181 }
182
183 static int
184 CIFSCreateMFSymLink(const unsigned int xid, struct cifs_tcon *tcon,
185 const char *fromName, const char *toName,
186 struct cifs_sb_info *cifs_sb)
187 {
188 int rc;
189 int oplock = 0;
190 int remap;
191 int create_options = CREATE_NOT_DIR;
192 __u16 netfid = 0;
193 u8 *buf;
194 unsigned int bytes_written = 0;
195 struct cifs_io_parms io_parms;
196 struct nls_table *nls_codepage;
197
198 nls_codepage = cifs_sb->local_nls;
199 remap = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR;
200
201 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
202 if (!buf)
203 return -ENOMEM;
204
205 rc = CIFSFormatMFSymlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
206 if (rc != 0) {
207 kfree(buf);
208 return rc;
209 }
210
211 if (backup_cred(cifs_sb))
212 create_options |= CREATE_OPEN_BACKUP_INTENT;
213
214 rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
215 create_options, &netfid, &oplock, NULL,
216 nls_codepage, remap);
217 if (rc != 0) {
218 kfree(buf);
219 return rc;
220 }
221
222 io_parms.netfid = netfid;
223 io_parms.pid = current->tgid;
224 io_parms.tcon = tcon;
225 io_parms.offset = 0;
226 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
227
228 rc = CIFSSMBWrite(xid, &io_parms, &bytes_written, buf, NULL, 0);
229 CIFSSMBClose(xid, tcon, netfid);
230 kfree(buf);
231 if (rc != 0)
232 return rc;
233
234 if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
235 return -EIO;
236
237 return 0;
238 }
239
240 static int
241 CIFSQueryMFSymLink(const unsigned int xid, struct cifs_tcon *tcon,
242 const unsigned char *searchName, char **symlinkinfo,
243 const struct nls_table *nls_codepage, int remap)
244 {
245 int rc;
246 int oplock = 0;
247 __u16 netfid = 0;
248 u8 *buf;
249 char *pbuf;
250 unsigned int bytes_read = 0;
251 int buf_type = CIFS_NO_BUFFER;
252 unsigned int link_len = 0;
253 struct cifs_io_parms io_parms;
254 FILE_ALL_INFO file_info;
255
256 rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
257 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
258 nls_codepage, remap);
259 if (rc != 0)
260 return rc;
261
262 if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
263 CIFSSMBClose(xid, tcon, netfid);
264 /* it's not a symlink */
265 return -EINVAL;
266 }
267
268 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
269 if (!buf)
270 return -ENOMEM;
271 pbuf = buf;
272 io_parms.netfid = netfid;
273 io_parms.pid = current->tgid;
274 io_parms.tcon = tcon;
275 io_parms.offset = 0;
276 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
277
278 rc = CIFSSMBRead(xid, &io_parms, &bytes_read, &pbuf, &buf_type);
279 CIFSSMBClose(xid, tcon, netfid);
280 if (rc != 0) {
281 kfree(buf);
282 return rc;
283 }
284
285 rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, symlinkinfo);
286 kfree(buf);
287 if (rc != 0)
288 return rc;
289
290 return 0;
291 }
292
293 bool
294 CIFSCouldBeMFSymlink(const struct cifs_fattr *fattr)
295 {
296 if (!(fattr->cf_mode & S_IFREG))
297 /* it's not a symlink */
298 return false;
299
300 if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
301 /* it's not a symlink */
302 return false;
303
304 return true;
305 }
306
307 int
308 open_query_close_cifs_symlink(const unsigned char *path, char *pbuf,
309 unsigned int *pbytes_read, struct cifs_sb_info *cifs_sb,
310 unsigned int xid)
311 {
312 int rc;
313 int oplock = 0;
314 __u16 netfid = 0;
315 struct tcon_link *tlink;
316 struct cifs_tcon *ptcon;
317 struct cifs_io_parms io_parms;
318 int buf_type = CIFS_NO_BUFFER;
319 FILE_ALL_INFO file_info;
320
321 tlink = cifs_sb_tlink(cifs_sb);
322 if (IS_ERR(tlink))
323 return PTR_ERR(tlink);
324 ptcon = tlink_tcon(tlink);
325
326 rc = CIFSSMBOpen(xid, ptcon, path, FILE_OPEN, GENERIC_READ,
327 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
328 cifs_sb->local_nls,
329 cifs_sb->mnt_cifs_flags &
330 CIFS_MOUNT_MAP_SPECIAL_CHR);
331 if (rc != 0) {
332 cifs_put_tlink(tlink);
333 return rc;
334 }
335
336 if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
337 CIFSSMBClose(xid, ptcon, netfid);
338 cifs_put_tlink(tlink);
339 /* it's not a symlink */
340 return rc;
341 }
342
343 io_parms.netfid = netfid;
344 io_parms.pid = current->tgid;
345 io_parms.tcon = ptcon;
346 io_parms.offset = 0;
347 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
348
349 rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
350 CIFSSMBClose(xid, ptcon, netfid);
351 cifs_put_tlink(tlink);
352 return rc;
353 }
354
355
356 int
357 CIFSCheckMFSymlink(unsigned int xid, struct cifs_tcon *tcon,
358 struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
359 const unsigned char *path)
360 {
361 int rc;
362 u8 *buf = NULL;
363 unsigned int link_len = 0;
364 unsigned int bytes_read = 0;
365
366 if (!CIFSCouldBeMFSymlink(fattr))
367 /* it's not a symlink */
368 return 0;
369
370 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
371 if (!buf)
372 return -ENOMEM;
373
374 if (tcon->ses->server->ops->query_mf_symlink)
375 rc = tcon->ses->server->ops->query_mf_symlink(path, buf,
376 &bytes_read, cifs_sb, xid);
377 else
378 rc = -ENOSYS;
379
380 if (rc)
381 goto out;
382
383 if (bytes_read == 0) /* not a symlink */
384 goto out;
385
386 rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL);
387 if (rc == -EINVAL) {
388 /* it's not a symlink */
389 rc = 0;
390 goto out;
391 }
392
393 if (rc != 0)
394 goto out;
395
396 /* it is a symlink */
397 fattr->cf_eof = link_len;
398 fattr->cf_mode &= ~S_IFMT;
399 fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
400 fattr->cf_dtype = DT_LNK;
401 out:
402 kfree(buf);
403 return rc;
404 }
405
406 int
407 cifs_hardlink(struct dentry *old_file, struct inode *inode,
408 struct dentry *direntry)
409 {
410 int rc = -EACCES;
411 unsigned int xid;
412 char *from_name = NULL;
413 char *to_name = NULL;
414 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
415 struct tcon_link *tlink;
416 struct cifs_tcon *tcon;
417 struct TCP_Server_Info *server;
418 struct cifsInodeInfo *cifsInode;
419
420 tlink = cifs_sb_tlink(cifs_sb);
421 if (IS_ERR(tlink))
422 return PTR_ERR(tlink);
423 tcon = tlink_tcon(tlink);
424
425 xid = get_xid();
426
427 from_name = build_path_from_dentry(old_file);
428 to_name = build_path_from_dentry(direntry);
429 if ((from_name == NULL) || (to_name == NULL)) {
430 rc = -ENOMEM;
431 goto cifs_hl_exit;
432 }
433
434 if (tcon->unix_ext)
435 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
436 cifs_sb->local_nls,
437 cifs_sb->mnt_cifs_flags &
438 CIFS_MOUNT_MAP_SPECIAL_CHR);
439 else {
440 server = tcon->ses->server;
441 if (!server->ops->create_hardlink)
442 return -ENOSYS;
443 rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
444 cifs_sb);
445 if ((rc == -EIO) || (rc == -EINVAL))
446 rc = -EOPNOTSUPP;
447 }
448
449 d_drop(direntry); /* force new lookup from server of target */
450
451 /*
452 * if source file is cached (oplocked) revalidate will not go to server
453 * until the file is closed or oplock broken so update nlinks locally
454 */
455 if (old_file->d_inode) {
456 cifsInode = CIFS_I(old_file->d_inode);
457 if (rc == 0) {
458 spin_lock(&old_file->d_inode->i_lock);
459 inc_nlink(old_file->d_inode);
460 spin_unlock(&old_file->d_inode->i_lock);
461 /*
462 * BB should we make this contingent on superblock flag
463 * NOATIME?
464 */
465 /* old_file->d_inode->i_ctime = CURRENT_TIME; */
466 /*
467 * parent dir timestamps will update from srv within a
468 * second, would it really be worth it to set the parent
469 * dir cifs inode time to zero to force revalidate
470 * (faster) for it too?
471 */
472 }
473 /*
474 * if not oplocked will force revalidate to get info on source
475 * file from srv
476 */
477 cifsInode->time = 0;
478
479 /*
480 * Will update parent dir timestamps from srv within a second.
481 * Would it really be worth it to set the parent dir (cifs
482 * inode) time field to zero to force revalidate on parent
483 * directory faster ie
484 *
485 * CIFS_I(inode)->time = 0;
486 */
487 }
488
489 cifs_hl_exit:
490 kfree(from_name);
491 kfree(to_name);
492 free_xid(xid);
493 cifs_put_tlink(tlink);
494 return rc;
495 }
496
497 void *
498 cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
499 {
500 struct inode *inode = direntry->d_inode;
501 int rc = -ENOMEM;
502 unsigned int xid;
503 char *full_path = NULL;
504 char *target_path = NULL;
505 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
506 struct tcon_link *tlink = NULL;
507 struct cifs_tcon *tcon;
508 struct TCP_Server_Info *server;
509
510 xid = get_xid();
511
512 tlink = cifs_sb_tlink(cifs_sb);
513 if (IS_ERR(tlink)) {
514 rc = PTR_ERR(tlink);
515 tlink = NULL;
516 goto out;
517 }
518 tcon = tlink_tcon(tlink);
519 server = tcon->ses->server;
520
521 full_path = build_path_from_dentry(direntry);
522 if (!full_path)
523 goto out;
524
525 cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
526
527 rc = -EACCES;
528 /*
529 * First try Minshall+French Symlinks, if configured
530 * and fallback to UNIX Extensions Symlinks.
531 */
532 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
533 rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
534 cifs_sb->local_nls,
535 cifs_sb->mnt_cifs_flags &
536 CIFS_MOUNT_MAP_SPECIAL_CHR);
537
538 if ((rc != 0) && cap_unix(tcon->ses))
539 rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
540 cifs_sb->local_nls);
541 else if (rc != 0 && server->ops->query_symlink)
542 rc = server->ops->query_symlink(xid, tcon, full_path,
543 &target_path, cifs_sb);
544
545 kfree(full_path);
546 out:
547 if (rc != 0) {
548 kfree(target_path);
549 target_path = ERR_PTR(rc);
550 }
551
552 free_xid(xid);
553 if (tlink)
554 cifs_put_tlink(tlink);
555 nd_set_link(nd, target_path);
556 return NULL;
557 }
558
559 int
560 cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
561 {
562 int rc = -EOPNOTSUPP;
563 unsigned int xid;
564 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
565 struct tcon_link *tlink;
566 struct cifs_tcon *pTcon;
567 char *full_path = NULL;
568 struct inode *newinode = NULL;
569
570 xid = get_xid();
571
572 tlink = cifs_sb_tlink(cifs_sb);
573 if (IS_ERR(tlink)) {
574 rc = PTR_ERR(tlink);
575 goto symlink_exit;
576 }
577 pTcon = tlink_tcon(tlink);
578
579 full_path = build_path_from_dentry(direntry);
580 if (full_path == NULL) {
581 rc = -ENOMEM;
582 goto symlink_exit;
583 }
584
585 cifs_dbg(FYI, "Full path: %s\n", full_path);
586 cifs_dbg(FYI, "symname is %s\n", symname);
587
588 /* BB what if DFS and this volume is on different share? BB */
589 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
590 rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
591 cifs_sb);
592 else if (pTcon->unix_ext)
593 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
594 cifs_sb->local_nls);
595 /* else
596 rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
597 cifs_sb_target->local_nls); */
598
599 if (rc == 0) {
600 if (pTcon->unix_ext)
601 rc = cifs_get_inode_info_unix(&newinode, full_path,
602 inode->i_sb, xid);
603 else
604 rc = cifs_get_inode_info(&newinode, full_path, NULL,
605 inode->i_sb, xid, NULL);
606
607 if (rc != 0) {
608 cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
609 rc);
610 } else {
611 d_instantiate(direntry, newinode);
612 }
613 }
614 symlink_exit:
615 kfree(full_path);
616 cifs_put_tlink(tlink);
617 free_xid(xid);
618 return rc;
619 }