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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/*
33 * M-F Symlink Functions - Begin
34 */
35
36#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
37#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
38#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
39#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
40#define CIFS_MF_SYMLINK_FILE_SIZE \
41 (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
42
43#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
44#define CIFS_MF_SYMLINK_MD5_FORMAT \
45 "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
46#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
47 md5_hash[0], md5_hash[1], md5_hash[2], md5_hash[3], \
48 md5_hash[4], md5_hash[5], md5_hash[6], md5_hash[7], \
49 md5_hash[8], md5_hash[9], md5_hash[10], md5_hash[11],\
50 md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
51
52static int
53symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
54{
55 int rc;
56 unsigned int size;
57 struct crypto_shash *md5;
58 struct sdesc *sdescmd5;
59
60 md5 = crypto_alloc_shash("md5", 0, 0);
61 if (IS_ERR(md5)) {
62 rc = PTR_ERR(md5);
63 cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
64 __func__, rc);
65 return rc;
66 }
67 size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
68 sdescmd5 = kmalloc(size, GFP_KERNEL);
69 if (!sdescmd5) {
70 rc = -ENOMEM;
71 goto symlink_hash_err;
72 }
73 sdescmd5->shash.tfm = md5;
74 sdescmd5->shash.flags = 0x0;
75
76 rc = crypto_shash_init(&sdescmd5->shash);
77 if (rc) {
78 cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
79 goto symlink_hash_err;
80 }
81 rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
82 if (rc) {
83 cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
84 goto symlink_hash_err;
85 }
86 rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
87 if (rc)
88 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
89
90symlink_hash_err:
91 crypto_free_shash(md5);
92 kfree(sdescmd5);
93
94 return rc;
95}
96
97static int
98parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
99 char **_link_str)
100{
101 int rc;
102 unsigned int link_len;
103 const char *md5_str1;
104 const char *link_str;
105 u8 md5_hash[16];
106 char md5_str2[34];
107
108 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
109 return -EINVAL;
110
111 md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
112 link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
113
114 rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
115 if (rc != 1)
116 return -EINVAL;
117
118 rc = symlink_hash(link_len, link_str, md5_hash);
119 if (rc) {
120 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
121 return rc;
122 }
123
124 snprintf(md5_str2, sizeof(md5_str2),
125 CIFS_MF_SYMLINK_MD5_FORMAT,
126 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
127
128 if (strncmp(md5_str1, md5_str2, 17) != 0)
129 return -EINVAL;
130
131 if (_link_str) {
132 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
133 if (!*_link_str)
134 return -ENOMEM;
135 }
136
137 *_link_len = link_len;
138 return 0;
139}
140
141static int
142format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
143{
144 int rc;
145 unsigned int link_len;
146 unsigned int ofs;
147 u8 md5_hash[16];
148
149 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
150 return -EINVAL;
151
152 link_len = strlen(link_str);
153
154 if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
155 return -ENAMETOOLONG;
156
157 rc = symlink_hash(link_len, link_str, md5_hash);
158 if (rc) {
159 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
160 return rc;
161 }
162
163 snprintf(buf, buf_len,
164 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
165 link_len,
166 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
167
168 ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
169 memcpy(buf + ofs, link_str, link_len);
170
171 ofs += link_len;
172 if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
173 buf[ofs] = '\n';
174 ofs++;
175 }
176
177 while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
178 buf[ofs] = ' ';
179 ofs++;
180 }
181
182 return 0;
183}
184
185bool
186couldbe_mf_symlink(const struct cifs_fattr *fattr)
187{
188 if (!S_ISREG(fattr->cf_mode))
189 /* it's not a symlink */
190 return false;
191
192 if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
193 /* it's not a symlink */
194 return false;
195
196 return true;
197}
198
199static int
200create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
201 struct cifs_sb_info *cifs_sb, const char *fromName,
202 const char *toName)
203{
204 int rc;
205 u8 *buf;
206 unsigned int bytes_written = 0;
207
208 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
209 if (!buf)
210 return -ENOMEM;
211
212 rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
213 if (rc)
214 goto out;
215
216 rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon, cifs_sb,
217 fromName, buf, &bytes_written);
218 if (rc)
219 goto out;
220
221 if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
222 rc = -EIO;
223out:
224 kfree(buf);
225 return rc;
226}
227
228static int
229query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
230 struct cifs_sb_info *cifs_sb, const unsigned char *path,
231 char **symlinkinfo)
232{
233 int rc;
234 u8 *buf = NULL;
235 unsigned int link_len = 0;
236 unsigned int bytes_read = 0;
237
238 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
239 if (!buf)
240 return -ENOMEM;
241
242 if (tcon->ses->server->ops->query_mf_symlink)
243 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
244 cifs_sb, path, buf, &bytes_read);
245 else
246 rc = -ENOSYS;
247
248 if (rc)
249 goto out;
250
251 if (bytes_read == 0) { /* not a symlink */
252 rc = -EINVAL;
253 goto out;
254 }
255
256 rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
257out:
258 kfree(buf);
259 return rc;
260}
261
262int
263check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
264 struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
265 const unsigned char *path)
266{
267 int rc;
268 u8 *buf = NULL;
269 unsigned int link_len = 0;
270 unsigned int bytes_read = 0;
271
272 if (!couldbe_mf_symlink(fattr))
273 /* it's not a symlink */
274 return 0;
275
276 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
277 if (!buf)
278 return -ENOMEM;
279
280 if (tcon->ses->server->ops->query_mf_symlink)
281 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
282 cifs_sb, path, buf, &bytes_read);
283 else
284 rc = -ENOSYS;
285
286 if (rc)
287 goto out;
288
289 if (bytes_read == 0) /* not a symlink */
290 goto out;
291
292 rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
293 if (rc == -EINVAL) {
294 /* it's not a symlink */
295 rc = 0;
296 goto out;
297 }
298
299 if (rc != 0)
300 goto out;
301
302 /* it is a symlink */
303 fattr->cf_eof = link_len;
304 fattr->cf_mode &= ~S_IFMT;
305 fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
306 fattr->cf_dtype = DT_LNK;
307out:
308 kfree(buf);
309 return rc;
310}
311
312/*
313 * SMB 1.0 Protocol specific functions
314 */
315
316int
317cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
318 struct cifs_sb_info *cifs_sb, const unsigned char *path,
319 char *pbuf, unsigned int *pbytes_read)
320{
321 int rc;
322 int oplock = 0;
323 struct cifs_fid fid;
324 struct cifs_open_parms oparms;
325 struct cifs_io_parms io_parms;
326 int buf_type = CIFS_NO_BUFFER;
327 FILE_ALL_INFO file_info;
328
329 oparms.tcon = tcon;
330 oparms.cifs_sb = cifs_sb;
331 oparms.desired_access = GENERIC_READ;
332 oparms.create_options = CREATE_NOT_DIR;
333 oparms.disposition = FILE_OPEN;
334 oparms.path = path;
335 oparms.fid = &fid;
336 oparms.reconnect = false;
337
338 rc = CIFS_open(xid, &oparms, &oplock, &file_info);
339 if (rc)
340 return rc;
341
342 if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE))
343 /* it's not a symlink */
344 goto out;
345
346 io_parms.netfid = fid.netfid;
347 io_parms.pid = current->tgid;
348 io_parms.tcon = tcon;
349 io_parms.offset = 0;
350 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
351
352 rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
353out:
354 CIFSSMBClose(xid, tcon, fid.netfid);
355 return rc;
356}
357
358int
359cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
360 struct cifs_sb_info *cifs_sb, const unsigned char *path,
361 char *pbuf, unsigned int *pbytes_written)
362{
363 int rc;
364 int oplock = 0;
365 struct cifs_fid fid;
366 struct cifs_open_parms oparms;
367 struct cifs_io_parms io_parms;
368 int create_options = CREATE_NOT_DIR;
369
370 if (backup_cred(cifs_sb))
371 create_options |= CREATE_OPEN_BACKUP_INTENT;
372
373 oparms.tcon = tcon;
374 oparms.cifs_sb = cifs_sb;
375 oparms.desired_access = GENERIC_WRITE;
376 oparms.create_options = create_options;
377 oparms.disposition = FILE_OPEN;
378 oparms.path = path;
379 oparms.fid = &fid;
380 oparms.reconnect = false;
381
382 rc = CIFS_open(xid, &oparms, &oplock, NULL);
383 if (rc)
384 return rc;
385
386 io_parms.netfid = fid.netfid;
387 io_parms.pid = current->tgid;
388 io_parms.tcon = tcon;
389 io_parms.offset = 0;
390 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
391
392 rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf, NULL, 0);
393 CIFSSMBClose(xid, tcon, fid.netfid);
394 return rc;
395}
396
397/*
398 * M-F Symlink Functions - End
399 */
400
401int
402cifs_hardlink(struct dentry *old_file, struct inode *inode,
403 struct dentry *direntry)
404{
405 int rc = -EACCES;
406 unsigned int xid;
407 char *from_name = NULL;
408 char *to_name = NULL;
409 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
410 struct tcon_link *tlink;
411 struct cifs_tcon *tcon;
412 struct TCP_Server_Info *server;
413 struct cifsInodeInfo *cifsInode;
414
415 tlink = cifs_sb_tlink(cifs_sb);
416 if (IS_ERR(tlink))
417 return PTR_ERR(tlink);
418 tcon = tlink_tcon(tlink);
419
420 xid = get_xid();
421
422 from_name = build_path_from_dentry(old_file);
423 to_name = build_path_from_dentry(direntry);
424 if ((from_name == NULL) || (to_name == NULL)) {
425 rc = -ENOMEM;
426 goto cifs_hl_exit;
427 }
428
429 if (tcon->unix_ext)
430 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
431 cifs_sb->local_nls,
432 cifs_sb->mnt_cifs_flags &
433 CIFS_MOUNT_MAP_SPECIAL_CHR);
434 else {
435 server = tcon->ses->server;
436 if (!server->ops->create_hardlink) {
437 rc = -ENOSYS;
438 goto cifs_hl_exit;
439 }
440 rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
441 cifs_sb);
442 if ((rc == -EIO) || (rc == -EINVAL))
443 rc = -EOPNOTSUPP;
444 }
445
446 d_drop(direntry); /* force new lookup from server of target */
447
448 /*
449 * if source file is cached (oplocked) revalidate will not go to server
450 * until the file is closed or oplock broken so update nlinks locally
451 */
452 if (old_file->d_inode) {
453 cifsInode = CIFS_I(old_file->d_inode);
454 if (rc == 0) {
455 spin_lock(&old_file->d_inode->i_lock);
456 inc_nlink(old_file->d_inode);
457 spin_unlock(&old_file->d_inode->i_lock);
458 /*
459 * BB should we make this contingent on superblock flag
460 * NOATIME?
461 */
462 /* old_file->d_inode->i_ctime = CURRENT_TIME; */
463 /*
464 * parent dir timestamps will update from srv within a
465 * second, would it really be worth it to set the parent
466 * dir cifs inode time to zero to force revalidate
467 * (faster) for it too?
468 */
469 }
470 /*
471 * if not oplocked will force revalidate to get info on source
472 * file from srv
473 */
474 cifsInode->time = 0;
475
476 /*
477 * Will update parent dir timestamps from srv within a second.
478 * Would it really be worth it to set the parent dir (cifs
479 * inode) time field to zero to force revalidate on parent
480 * directory faster ie
481 *
482 * CIFS_I(inode)->time = 0;
483 */
484 }
485
486cifs_hl_exit:
487 kfree(from_name);
488 kfree(to_name);
489 free_xid(xid);
490 cifs_put_tlink(tlink);
491 return rc;
492}
493
494void *
495cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
496{
497 struct inode *inode = direntry->d_inode;
498 int rc = -ENOMEM;
499 unsigned int xid;
500 char *full_path = NULL;
501 char *target_path = NULL;
502 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
503 struct tcon_link *tlink = NULL;
504 struct cifs_tcon *tcon;
505 struct TCP_Server_Info *server;
506
507 xid = get_xid();
508
509 tlink = cifs_sb_tlink(cifs_sb);
510 if (IS_ERR(tlink)) {
511 rc = PTR_ERR(tlink);
512 tlink = NULL;
513 goto out;
514 }
515 tcon = tlink_tcon(tlink);
516 server = tcon->ses->server;
517
518 full_path = build_path_from_dentry(direntry);
519 if (!full_path)
520 goto out;
521
522 cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
523
524 rc = -EACCES;
525 /*
526 * First try Minshall+French Symlinks, if configured
527 * and fallback to UNIX Extensions Symlinks.
528 */
529 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
530 rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
531 &target_path);
532
533 if (rc != 0 && server->ops->query_symlink)
534 rc = server->ops->query_symlink(xid, tcon, full_path,
535 &target_path, cifs_sb);
536
537 kfree(full_path);
538out:
539 if (rc != 0) {
540 kfree(target_path);
541 target_path = ERR_PTR(rc);
542 }
543
544 free_xid(xid);
545 if (tlink)
546 cifs_put_tlink(tlink);
547 nd_set_link(nd, target_path);
548 return NULL;
549}
550
551int
552cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
553{
554 int rc = -EOPNOTSUPP;
555 unsigned int xid;
556 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
557 struct tcon_link *tlink;
558 struct cifs_tcon *pTcon;
559 char *full_path = NULL;
560 struct inode *newinode = NULL;
561
562 xid = get_xid();
563
564 tlink = cifs_sb_tlink(cifs_sb);
565 if (IS_ERR(tlink)) {
566 rc = PTR_ERR(tlink);
567 goto symlink_exit;
568 }
569 pTcon = tlink_tcon(tlink);
570
571 full_path = build_path_from_dentry(direntry);
572 if (full_path == NULL) {
573 rc = -ENOMEM;
574 goto symlink_exit;
575 }
576
577 cifs_dbg(FYI, "Full path: %s\n", full_path);
578 cifs_dbg(FYI, "symname is %s\n", symname);
579
580 /* BB what if DFS and this volume is on different share? BB */
581 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
582 rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
583 else if (pTcon->unix_ext)
584 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
585 cifs_sb->local_nls);
586 /* else
587 rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
588 cifs_sb_target->local_nls); */
589
590 if (rc == 0) {
591 if (pTcon->unix_ext)
592 rc = cifs_get_inode_info_unix(&newinode, full_path,
593 inode->i_sb, xid);
594 else
595 rc = cifs_get_inode_info(&newinode, full_path, NULL,
596 inode->i_sb, xid, NULL);
597
598 if (rc != 0) {
599 cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
600 rc);
601 } else {
602 d_instantiate(direntry, newinode);
603 }
604 }
605symlink_exit:
606 kfree(full_path);
607 cifs_put_tlink(tlink);
608 free_xid(xid);
609 return rc;
610}
1// SPDX-License-Identifier: LGPL-2.1
2/*
3 * fs/cifs/link.c
4 *
5 * Copyright (C) International Business Machines Corp., 2002,2008
6 * Author(s): Steve French (sfrench@us.ibm.com)
7 *
8 */
9#include <linux/fs.h>
10#include <linux/stat.h>
11#include <linux/slab.h>
12#include <linux/namei.h>
13#include "cifsfs.h"
14#include "cifspdu.h"
15#include "cifsglob.h"
16#include "cifsproto.h"
17#include "cifs_debug.h"
18#include "cifs_fs_sb.h"
19#include "cifs_unicode.h"
20#include "smb2proto.h"
21#include "cifs_ioctl.h"
22
23/*
24 * M-F Symlink Functions - Begin
25 */
26
27#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
28#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
29#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
30#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
31#define CIFS_MF_SYMLINK_FILE_SIZE \
32 (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
33
34#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
35#define CIFS_MF_SYMLINK_MD5_FORMAT "%16phN\n"
36#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash
37
38static int
39symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
40{
41 int rc;
42 struct crypto_shash *md5 = NULL;
43 struct sdesc *sdescmd5 = NULL;
44
45 rc = cifs_alloc_hash("md5", &md5, &sdescmd5);
46 if (rc)
47 goto symlink_hash_err;
48
49 rc = crypto_shash_init(&sdescmd5->shash);
50 if (rc) {
51 cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
52 goto symlink_hash_err;
53 }
54 rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
55 if (rc) {
56 cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
57 goto symlink_hash_err;
58 }
59 rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
60 if (rc)
61 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
62
63symlink_hash_err:
64 cifs_free_hash(&md5, &sdescmd5);
65 return rc;
66}
67
68static int
69parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
70 char **_link_str)
71{
72 int rc;
73 unsigned int link_len;
74 const char *md5_str1;
75 const char *link_str;
76 u8 md5_hash[16];
77 char md5_str2[34];
78
79 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
80 return -EINVAL;
81
82 md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
83 link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
84
85 rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
86 if (rc != 1)
87 return -EINVAL;
88
89 rc = symlink_hash(link_len, link_str, md5_hash);
90 if (rc) {
91 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
92 return rc;
93 }
94
95 scnprintf(md5_str2, sizeof(md5_str2),
96 CIFS_MF_SYMLINK_MD5_FORMAT,
97 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
98
99 if (strncmp(md5_str1, md5_str2, 17) != 0)
100 return -EINVAL;
101
102 if (_link_str) {
103 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
104 if (!*_link_str)
105 return -ENOMEM;
106 }
107
108 *_link_len = link_len;
109 return 0;
110}
111
112static int
113format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
114{
115 int rc;
116 unsigned int link_len;
117 unsigned int ofs;
118 u8 md5_hash[16];
119
120 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
121 return -EINVAL;
122
123 link_len = strlen(link_str);
124
125 if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
126 return -ENAMETOOLONG;
127
128 rc = symlink_hash(link_len, link_str, md5_hash);
129 if (rc) {
130 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
131 return rc;
132 }
133
134 scnprintf(buf, buf_len,
135 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
136 link_len,
137 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
138
139 ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
140 memcpy(buf + ofs, link_str, link_len);
141
142 ofs += link_len;
143 if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
144 buf[ofs] = '\n';
145 ofs++;
146 }
147
148 while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
149 buf[ofs] = ' ';
150 ofs++;
151 }
152
153 return 0;
154}
155
156bool
157couldbe_mf_symlink(const struct cifs_fattr *fattr)
158{
159 if (!S_ISREG(fattr->cf_mode))
160 /* it's not a symlink */
161 return false;
162
163 if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
164 /* it's not a symlink */
165 return false;
166
167 return true;
168}
169
170static int
171create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
172 struct cifs_sb_info *cifs_sb, const char *fromName,
173 const char *toName)
174{
175 int rc;
176 u8 *buf;
177 unsigned int bytes_written = 0;
178
179 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
180 if (!buf)
181 return -ENOMEM;
182
183 rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
184 if (rc)
185 goto out;
186
187 if (tcon->ses->server->ops->create_mf_symlink)
188 rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
189 cifs_sb, fromName, buf, &bytes_written);
190 else
191 rc = -EOPNOTSUPP;
192
193 if (rc)
194 goto out;
195
196 if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
197 rc = -EIO;
198out:
199 kfree(buf);
200 return rc;
201}
202
203static int
204query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
205 struct cifs_sb_info *cifs_sb, const unsigned char *path,
206 char **symlinkinfo)
207{
208 int rc;
209 u8 *buf = NULL;
210 unsigned int link_len = 0;
211 unsigned int bytes_read = 0;
212
213 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
214 if (!buf)
215 return -ENOMEM;
216
217 if (tcon->ses->server->ops->query_mf_symlink)
218 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
219 cifs_sb, path, buf, &bytes_read);
220 else
221 rc = -ENOSYS;
222
223 if (rc)
224 goto out;
225
226 if (bytes_read == 0) { /* not a symlink */
227 rc = -EINVAL;
228 goto out;
229 }
230
231 rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
232out:
233 kfree(buf);
234 return rc;
235}
236
237int
238check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
239 struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
240 const unsigned char *path)
241{
242 int rc;
243 u8 *buf = NULL;
244 unsigned int link_len = 0;
245 unsigned int bytes_read = 0;
246
247 if (!couldbe_mf_symlink(fattr))
248 /* it's not a symlink */
249 return 0;
250
251 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
252 if (!buf)
253 return -ENOMEM;
254
255 if (tcon->ses->server->ops->query_mf_symlink)
256 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
257 cifs_sb, path, buf, &bytes_read);
258 else
259 rc = -ENOSYS;
260
261 if (rc)
262 goto out;
263
264 if (bytes_read == 0) /* not a symlink */
265 goto out;
266
267 rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
268 if (rc == -EINVAL) {
269 /* it's not a symlink */
270 rc = 0;
271 goto out;
272 }
273
274 if (rc != 0)
275 goto out;
276
277 /* it is a symlink */
278 fattr->cf_eof = link_len;
279 fattr->cf_mode &= ~S_IFMT;
280 fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
281 fattr->cf_dtype = DT_LNK;
282out:
283 kfree(buf);
284 return rc;
285}
286
287/*
288 * SMB 1.0 Protocol specific functions
289 */
290
291int
292cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
293 struct cifs_sb_info *cifs_sb, const unsigned char *path,
294 char *pbuf, unsigned int *pbytes_read)
295{
296 int rc;
297 int oplock = 0;
298 struct cifs_fid fid;
299 struct cifs_open_parms oparms;
300 struct cifs_io_parms io_parms = {0};
301 int buf_type = CIFS_NO_BUFFER;
302 FILE_ALL_INFO file_info;
303
304 oparms.tcon = tcon;
305 oparms.cifs_sb = cifs_sb;
306 oparms.desired_access = GENERIC_READ;
307 oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
308 oparms.disposition = FILE_OPEN;
309 oparms.path = path;
310 oparms.fid = &fid;
311 oparms.reconnect = false;
312
313 rc = CIFS_open(xid, &oparms, &oplock, &file_info);
314 if (rc)
315 return rc;
316
317 if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
318 rc = -ENOENT;
319 /* it's not a symlink */
320 goto out;
321 }
322
323 io_parms.netfid = fid.netfid;
324 io_parms.pid = current->tgid;
325 io_parms.tcon = tcon;
326 io_parms.offset = 0;
327 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
328
329 rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
330out:
331 CIFSSMBClose(xid, tcon, fid.netfid);
332 return rc;
333}
334
335int
336cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
337 struct cifs_sb_info *cifs_sb, const unsigned char *path,
338 char *pbuf, unsigned int *pbytes_written)
339{
340 int rc;
341 int oplock = 0;
342 struct cifs_fid fid;
343 struct cifs_open_parms oparms;
344 struct cifs_io_parms io_parms = {0};
345
346 oparms.tcon = tcon;
347 oparms.cifs_sb = cifs_sb;
348 oparms.desired_access = GENERIC_WRITE;
349 oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
350 oparms.disposition = FILE_CREATE;
351 oparms.path = path;
352 oparms.fid = &fid;
353 oparms.reconnect = false;
354
355 rc = CIFS_open(xid, &oparms, &oplock, NULL);
356 if (rc)
357 return rc;
358
359 io_parms.netfid = fid.netfid;
360 io_parms.pid = current->tgid;
361 io_parms.tcon = tcon;
362 io_parms.offset = 0;
363 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
364
365 rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf);
366 CIFSSMBClose(xid, tcon, fid.netfid);
367 return rc;
368}
369
370/*
371 * SMB 2.1/SMB3 Protocol specific functions
372 */
373int
374smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
375 struct cifs_sb_info *cifs_sb, const unsigned char *path,
376 char *pbuf, unsigned int *pbytes_read)
377{
378 int rc;
379 struct cifs_fid fid;
380 struct cifs_open_parms oparms;
381 struct cifs_io_parms io_parms = {0};
382 int buf_type = CIFS_NO_BUFFER;
383 __le16 *utf16_path;
384 __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
385 struct smb2_file_all_info *pfile_info = NULL;
386
387 oparms.tcon = tcon;
388 oparms.cifs_sb = cifs_sb;
389 oparms.desired_access = GENERIC_READ;
390 oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
391 oparms.disposition = FILE_OPEN;
392 oparms.fid = &fid;
393 oparms.reconnect = false;
394
395 utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
396 if (utf16_path == NULL)
397 return -ENOMEM;
398
399 pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
400 GFP_KERNEL);
401
402 if (pfile_info == NULL) {
403 kfree(utf16_path);
404 return -ENOMEM;
405 }
406
407 rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL,
408 NULL, NULL);
409 if (rc)
410 goto qmf_out_open_fail;
411
412 if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
413 /* it's not a symlink */
414 rc = -ENOENT; /* Is there a better rc to return? */
415 goto qmf_out;
416 }
417
418 io_parms.netfid = fid.netfid;
419 io_parms.pid = current->tgid;
420 io_parms.tcon = tcon;
421 io_parms.offset = 0;
422 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
423 io_parms.persistent_fid = fid.persistent_fid;
424 io_parms.volatile_fid = fid.volatile_fid;
425 rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
426qmf_out:
427 SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
428qmf_out_open_fail:
429 kfree(utf16_path);
430 kfree(pfile_info);
431 return rc;
432}
433
434int
435smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
436 struct cifs_sb_info *cifs_sb, const unsigned char *path,
437 char *pbuf, unsigned int *pbytes_written)
438{
439 int rc;
440 struct cifs_fid fid;
441 struct cifs_open_parms oparms;
442 struct cifs_io_parms io_parms = {0};
443 __le16 *utf16_path;
444 __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
445 struct kvec iov[2];
446
447 cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
448
449 utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
450 if (!utf16_path)
451 return -ENOMEM;
452
453 oparms.tcon = tcon;
454 oparms.cifs_sb = cifs_sb;
455 oparms.desired_access = GENERIC_WRITE;
456 oparms.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR);
457 oparms.disposition = FILE_CREATE;
458 oparms.fid = &fid;
459 oparms.reconnect = false;
460
461 rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL,
462 NULL, NULL);
463 if (rc) {
464 kfree(utf16_path);
465 return rc;
466 }
467
468 io_parms.netfid = fid.netfid;
469 io_parms.pid = current->tgid;
470 io_parms.tcon = tcon;
471 io_parms.offset = 0;
472 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
473 io_parms.persistent_fid = fid.persistent_fid;
474 io_parms.volatile_fid = fid.volatile_fid;
475
476 /* iov[0] is reserved for smb header */
477 iov[1].iov_base = pbuf;
478 iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE;
479
480 rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1);
481
482 /* Make sure we wrote all of the symlink data */
483 if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE))
484 rc = -EIO;
485
486 SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
487
488 kfree(utf16_path);
489 return rc;
490}
491
492/*
493 * M-F Symlink Functions - End
494 */
495
496int
497cifs_hardlink(struct dentry *old_file, struct inode *inode,
498 struct dentry *direntry)
499{
500 int rc = -EACCES;
501 unsigned int xid;
502 const char *from_name, *to_name;
503 void *page1, *page2;
504 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
505 struct tcon_link *tlink;
506 struct cifs_tcon *tcon;
507 struct TCP_Server_Info *server;
508 struct cifsInodeInfo *cifsInode;
509
510 if (unlikely(cifs_forced_shutdown(cifs_sb)))
511 return -EIO;
512
513 tlink = cifs_sb_tlink(cifs_sb);
514 if (IS_ERR(tlink))
515 return PTR_ERR(tlink);
516 tcon = tlink_tcon(tlink);
517
518 xid = get_xid();
519 page1 = alloc_dentry_path();
520 page2 = alloc_dentry_path();
521
522 from_name = build_path_from_dentry(old_file, page1);
523 if (IS_ERR(from_name)) {
524 rc = PTR_ERR(from_name);
525 goto cifs_hl_exit;
526 }
527 to_name = build_path_from_dentry(direntry, page2);
528 if (IS_ERR(to_name)) {
529 rc = PTR_ERR(to_name);
530 goto cifs_hl_exit;
531 }
532
533 if (tcon->unix_ext)
534 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
535 cifs_sb->local_nls,
536 cifs_remap(cifs_sb));
537 else {
538 server = tcon->ses->server;
539 if (!server->ops->create_hardlink) {
540 rc = -ENOSYS;
541 goto cifs_hl_exit;
542 }
543 rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
544 cifs_sb);
545 if ((rc == -EIO) || (rc == -EINVAL))
546 rc = -EOPNOTSUPP;
547 }
548
549 d_drop(direntry); /* force new lookup from server of target */
550
551 /*
552 * if source file is cached (oplocked) revalidate will not go to server
553 * until the file is closed or oplock broken so update nlinks locally
554 */
555 if (d_really_is_positive(old_file)) {
556 cifsInode = CIFS_I(d_inode(old_file));
557 if (rc == 0) {
558 spin_lock(&d_inode(old_file)->i_lock);
559 inc_nlink(d_inode(old_file));
560 spin_unlock(&d_inode(old_file)->i_lock);
561
562 /*
563 * parent dir timestamps will update from srv within a
564 * second, would it really be worth it to set the parent
565 * dir cifs inode time to zero to force revalidate
566 * (faster) for it too?
567 */
568 }
569 /*
570 * if not oplocked will force revalidate to get info on source
571 * file from srv. Note Samba server prior to 4.2 has bug -
572 * not updating src file ctime on hardlinks but Windows servers
573 * handle it properly
574 */
575 cifsInode->time = 0;
576
577 /*
578 * Will update parent dir timestamps from srv within a second.
579 * Would it really be worth it to set the parent dir (cifs
580 * inode) time field to zero to force revalidate on parent
581 * directory faster ie
582 *
583 * CIFS_I(inode)->time = 0;
584 */
585 }
586
587cifs_hl_exit:
588 free_dentry_path(page1);
589 free_dentry_path(page2);
590 free_xid(xid);
591 cifs_put_tlink(tlink);
592 return rc;
593}
594
595const char *
596cifs_get_link(struct dentry *direntry, struct inode *inode,
597 struct delayed_call *done)
598{
599 int rc = -ENOMEM;
600 unsigned int xid;
601 const char *full_path;
602 void *page;
603 char *target_path = NULL;
604 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
605 struct tcon_link *tlink = NULL;
606 struct cifs_tcon *tcon;
607 struct TCP_Server_Info *server;
608
609 if (!direntry)
610 return ERR_PTR(-ECHILD);
611
612 xid = get_xid();
613
614 tlink = cifs_sb_tlink(cifs_sb);
615 if (IS_ERR(tlink)) {
616 free_xid(xid);
617 return ERR_CAST(tlink);
618 }
619 tcon = tlink_tcon(tlink);
620 server = tcon->ses->server;
621
622 page = alloc_dentry_path();
623 full_path = build_path_from_dentry(direntry, page);
624 if (IS_ERR(full_path)) {
625 free_xid(xid);
626 cifs_put_tlink(tlink);
627 free_dentry_path(page);
628 return ERR_CAST(full_path);
629 }
630
631 cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
632
633 rc = -EACCES;
634 /*
635 * First try Minshall+French Symlinks, if configured
636 * and fallback to UNIX Extensions Symlinks.
637 */
638 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
639 rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
640 &target_path);
641
642 if (rc != 0 && server->ops->query_symlink) {
643 struct cifsInodeInfo *cifsi = CIFS_I(inode);
644 bool reparse_point = false;
645
646 if (cifsi->cifsAttrs & ATTR_REPARSE)
647 reparse_point = true;
648
649 rc = server->ops->query_symlink(xid, tcon, cifs_sb, full_path,
650 &target_path, reparse_point);
651 }
652
653 free_dentry_path(page);
654 free_xid(xid);
655 cifs_put_tlink(tlink);
656 if (rc != 0) {
657 kfree(target_path);
658 return ERR_PTR(rc);
659 }
660 set_delayed_call(done, kfree_link, target_path);
661 return target_path;
662}
663
664int
665cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
666 struct dentry *direntry, const char *symname)
667{
668 int rc = -EOPNOTSUPP;
669 unsigned int xid;
670 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
671 struct tcon_link *tlink;
672 struct cifs_tcon *pTcon;
673 const char *full_path;
674 void *page;
675 struct inode *newinode = NULL;
676
677 if (unlikely(cifs_forced_shutdown(cifs_sb)))
678 return -EIO;
679
680 page = alloc_dentry_path();
681 if (!page)
682 return -ENOMEM;
683
684 xid = get_xid();
685
686 tlink = cifs_sb_tlink(cifs_sb);
687 if (IS_ERR(tlink)) {
688 rc = PTR_ERR(tlink);
689 goto symlink_exit;
690 }
691 pTcon = tlink_tcon(tlink);
692
693 full_path = build_path_from_dentry(direntry, page);
694 if (IS_ERR(full_path)) {
695 rc = PTR_ERR(full_path);
696 goto symlink_exit;
697 }
698
699 cifs_dbg(FYI, "Full path: %s\n", full_path);
700 cifs_dbg(FYI, "symname is %s\n", symname);
701
702 /* BB what if DFS and this volume is on different share? BB */
703 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
704 rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
705 else if (pTcon->unix_ext)
706 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
707 cifs_sb->local_nls,
708 cifs_remap(cifs_sb));
709 /* else
710 rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
711 cifs_sb_target->local_nls); */
712
713 if (rc == 0) {
714 if (pTcon->posix_extensions)
715 rc = smb311_posix_get_inode_info(&newinode, full_path, inode->i_sb, xid);
716 else if (pTcon->unix_ext)
717 rc = cifs_get_inode_info_unix(&newinode, full_path,
718 inode->i_sb, xid);
719 else
720 rc = cifs_get_inode_info(&newinode, full_path, NULL,
721 inode->i_sb, xid, NULL);
722
723 if (rc != 0) {
724 cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
725 rc);
726 } else {
727 d_instantiate(direntry, newinode);
728 }
729 }
730symlink_exit:
731 free_dentry_path(page);
732 cifs_put_tlink(tlink);
733 free_xid(xid);
734 return rc;
735}