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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#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
48static int
49symlink_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 cERROR(1, "%s: Crypto md5 allocation error %d\n", __func__, rc);
60 return rc;
61 }
62 size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
63 sdescmd5 = kmalloc(size, GFP_KERNEL);
64 if (!sdescmd5) {
65 rc = -ENOMEM;
66 cERROR(1, "%s: Memory allocation failure\n", __func__);
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 cERROR(1, "%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 cERROR(1, "%s: Could not update iwth link_str\n", __func__);
80 goto symlink_hash_err;
81 }
82 rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
83 if (rc)
84 cERROR(1, "%s: Could not generate md5 hash\n", __func__);
85
86symlink_hash_err:
87 crypto_free_shash(md5);
88 kfree(sdescmd5);
89
90 return rc;
91}
92
93static int
94CIFSParseMFSymlink(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 cFYI(1, "%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
139static int
140CIFSFormatMFSymlink(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 cFYI(1, "%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
183static int
184CIFSCreateMFSymLink(const int xid, struct cifs_tcon *tcon,
185 const char *fromName, const char *toName,
186 const struct nls_table *nls_codepage, int remap)
187{
188 int rc;
189 int oplock = 0;
190 __u16 netfid = 0;
191 u8 *buf;
192 unsigned int bytes_written = 0;
193 struct cifs_io_parms io_parms;
194
195 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
196 if (!buf)
197 return -ENOMEM;
198
199 rc = CIFSFormatMFSymlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
200 if (rc != 0) {
201 kfree(buf);
202 return rc;
203 }
204
205 rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
206 CREATE_NOT_DIR, &netfid, &oplock, NULL,
207 nls_codepage, remap);
208 if (rc != 0) {
209 kfree(buf);
210 return rc;
211 }
212
213 io_parms.netfid = netfid;
214 io_parms.pid = current->tgid;
215 io_parms.tcon = tcon;
216 io_parms.offset = 0;
217 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
218
219 rc = CIFSSMBWrite(xid, &io_parms, &bytes_written, buf, NULL, 0);
220 CIFSSMBClose(xid, tcon, netfid);
221 kfree(buf);
222 if (rc != 0)
223 return rc;
224
225 if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
226 return -EIO;
227
228 return 0;
229}
230
231static int
232CIFSQueryMFSymLink(const int xid, struct cifs_tcon *tcon,
233 const unsigned char *searchName, char **symlinkinfo,
234 const struct nls_table *nls_codepage, int remap)
235{
236 int rc;
237 int oplock = 0;
238 __u16 netfid = 0;
239 u8 *buf;
240 char *pbuf;
241 unsigned int bytes_read = 0;
242 int buf_type = CIFS_NO_BUFFER;
243 unsigned int link_len = 0;
244 struct cifs_io_parms io_parms;
245 FILE_ALL_INFO file_info;
246
247 rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
248 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
249 nls_codepage, remap);
250 if (rc != 0)
251 return rc;
252
253 if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
254 CIFSSMBClose(xid, tcon, netfid);
255 /* it's not a symlink */
256 return -EINVAL;
257 }
258
259 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
260 if (!buf)
261 return -ENOMEM;
262 pbuf = buf;
263 io_parms.netfid = netfid;
264 io_parms.pid = current->tgid;
265 io_parms.tcon = tcon;
266 io_parms.offset = 0;
267 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
268
269 rc = CIFSSMBRead(xid, &io_parms, &bytes_read, &pbuf, &buf_type);
270 CIFSSMBClose(xid, tcon, netfid);
271 if (rc != 0) {
272 kfree(buf);
273 return rc;
274 }
275
276 rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, symlinkinfo);
277 kfree(buf);
278 if (rc != 0)
279 return rc;
280
281 return 0;
282}
283
284bool
285CIFSCouldBeMFSymlink(const struct cifs_fattr *fattr)
286{
287 if (!(fattr->cf_mode & S_IFREG))
288 /* it's not a symlink */
289 return false;
290
291 if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
292 /* it's not a symlink */
293 return false;
294
295 return true;
296}
297
298int
299CIFSCheckMFSymlink(struct cifs_fattr *fattr,
300 const unsigned char *path,
301 struct cifs_sb_info *cifs_sb, int xid)
302{
303 int rc;
304 int oplock = 0;
305 __u16 netfid = 0;
306 struct tcon_link *tlink;
307 struct cifs_tcon *pTcon;
308 struct cifs_io_parms io_parms;
309 u8 *buf;
310 char *pbuf;
311 unsigned int bytes_read = 0;
312 int buf_type = CIFS_NO_BUFFER;
313 unsigned int link_len = 0;
314 FILE_ALL_INFO file_info;
315
316 if (!CIFSCouldBeMFSymlink(fattr))
317 /* it's not a symlink */
318 return 0;
319
320 tlink = cifs_sb_tlink(cifs_sb);
321 if (IS_ERR(tlink))
322 return PTR_ERR(tlink);
323 pTcon = tlink_tcon(tlink);
324
325 rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
326 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
327 cifs_sb->local_nls,
328 cifs_sb->mnt_cifs_flags &
329 CIFS_MOUNT_MAP_SPECIAL_CHR);
330 if (rc != 0)
331 goto out;
332
333 if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
334 CIFSSMBClose(xid, pTcon, netfid);
335 /* it's not a symlink */
336 goto out;
337 }
338
339 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
340 if (!buf) {
341 rc = -ENOMEM;
342 goto out;
343 }
344 pbuf = buf;
345 io_parms.netfid = netfid;
346 io_parms.pid = current->tgid;
347 io_parms.tcon = pTcon;
348 io_parms.offset = 0;
349 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
350
351 rc = CIFSSMBRead(xid, &io_parms, &bytes_read, &pbuf, &buf_type);
352 CIFSSMBClose(xid, pTcon, netfid);
353 if (rc != 0) {
354 kfree(buf);
355 goto out;
356 }
357
358 rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL);
359 kfree(buf);
360 if (rc == -EINVAL) {
361 /* it's not a symlink */
362 rc = 0;
363 goto out;
364 }
365
366 if (rc != 0)
367 goto out;
368
369 /* it is a symlink */
370 fattr->cf_eof = link_len;
371 fattr->cf_mode &= ~S_IFMT;
372 fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
373 fattr->cf_dtype = DT_LNK;
374out:
375 cifs_put_tlink(tlink);
376 return rc;
377}
378
379int
380cifs_hardlink(struct dentry *old_file, struct inode *inode,
381 struct dentry *direntry)
382{
383 int rc = -EACCES;
384 int xid;
385 char *fromName = NULL;
386 char *toName = NULL;
387 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
388 struct tcon_link *tlink;
389 struct cifs_tcon *pTcon;
390 struct cifsInodeInfo *cifsInode;
391
392 tlink = cifs_sb_tlink(cifs_sb);
393 if (IS_ERR(tlink))
394 return PTR_ERR(tlink);
395 pTcon = tlink_tcon(tlink);
396
397 xid = GetXid();
398
399 fromName = build_path_from_dentry(old_file);
400 toName = build_path_from_dentry(direntry);
401 if ((fromName == NULL) || (toName == NULL)) {
402 rc = -ENOMEM;
403 goto cifs_hl_exit;
404 }
405
406 if (pTcon->unix_ext)
407 rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
408 cifs_sb->local_nls,
409 cifs_sb->mnt_cifs_flags &
410 CIFS_MOUNT_MAP_SPECIAL_CHR);
411 else {
412 rc = CIFSCreateHardLink(xid, pTcon, fromName, toName,
413 cifs_sb->local_nls,
414 cifs_sb->mnt_cifs_flags &
415 CIFS_MOUNT_MAP_SPECIAL_CHR);
416 if ((rc == -EIO) || (rc == -EINVAL))
417 rc = -EOPNOTSUPP;
418 }
419
420 d_drop(direntry); /* force new lookup from server of target */
421
422 /* if source file is cached (oplocked) revalidate will not go to server
423 until the file is closed or oplock broken so update nlinks locally */
424 if (old_file->d_inode) {
425 cifsInode = CIFS_I(old_file->d_inode);
426 if (rc == 0) {
427 old_file->d_inode->i_nlink++;
428/* BB should we make this contingent on superblock flag NOATIME? */
429/* old_file->d_inode->i_ctime = CURRENT_TIME;*/
430 /* parent dir timestamps will update from srv
431 within a second, would it really be worth it
432 to set the parent dir cifs inode time to zero
433 to force revalidate (faster) for it too? */
434 }
435 /* if not oplocked will force revalidate to get info
436 on source file from srv */
437 cifsInode->time = 0;
438
439 /* Will update parent dir timestamps from srv within a second.
440 Would it really be worth it to set the parent dir (cifs
441 inode) time field to zero to force revalidate on parent
442 directory faster ie
443 CIFS_I(inode)->time = 0; */
444 }
445
446cifs_hl_exit:
447 kfree(fromName);
448 kfree(toName);
449 FreeXid(xid);
450 cifs_put_tlink(tlink);
451 return rc;
452}
453
454void *
455cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
456{
457 struct inode *inode = direntry->d_inode;
458 int rc = -ENOMEM;
459 int xid;
460 char *full_path = NULL;
461 char *target_path = NULL;
462 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
463 struct tcon_link *tlink = NULL;
464 struct cifs_tcon *tcon;
465
466 xid = GetXid();
467
468 tlink = cifs_sb_tlink(cifs_sb);
469 if (IS_ERR(tlink)) {
470 rc = PTR_ERR(tlink);
471 tlink = NULL;
472 goto out;
473 }
474 tcon = tlink_tcon(tlink);
475
476 /*
477 * For now, we just handle symlinks with unix extensions enabled.
478 * Eventually we should handle NTFS reparse points, and MacOS
479 * symlink support. For instance...
480 *
481 * rc = CIFSSMBQueryReparseLinkInfo(...)
482 *
483 * For now, just return -EACCES when the server doesn't support posix
484 * extensions. Note that we still allow querying symlinks when posix
485 * extensions are manually disabled. We could disable these as well
486 * but there doesn't seem to be any harm in allowing the client to
487 * read them.
488 */
489 if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
490 && !(tcon->ses->capabilities & CAP_UNIX)) {
491 rc = -EACCES;
492 goto out;
493 }
494
495 full_path = build_path_from_dentry(direntry);
496 if (!full_path)
497 goto out;
498
499 cFYI(1, "Full path: %s inode = 0x%p", full_path, inode);
500
501 rc = -EACCES;
502 /*
503 * First try Minshall+French Symlinks, if configured
504 * and fallback to UNIX Extensions Symlinks.
505 */
506 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
507 rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
508 cifs_sb->local_nls,
509 cifs_sb->mnt_cifs_flags &
510 CIFS_MOUNT_MAP_SPECIAL_CHR);
511
512 if ((rc != 0) && (tcon->ses->capabilities & CAP_UNIX))
513 rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
514 cifs_sb->local_nls);
515
516 kfree(full_path);
517out:
518 if (rc != 0) {
519 kfree(target_path);
520 target_path = ERR_PTR(rc);
521 }
522
523 FreeXid(xid);
524 if (tlink)
525 cifs_put_tlink(tlink);
526 nd_set_link(nd, target_path);
527 return NULL;
528}
529
530int
531cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
532{
533 int rc = -EOPNOTSUPP;
534 int xid;
535 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
536 struct tcon_link *tlink;
537 struct cifs_tcon *pTcon;
538 char *full_path = NULL;
539 struct inode *newinode = NULL;
540
541 xid = GetXid();
542
543 tlink = cifs_sb_tlink(cifs_sb);
544 if (IS_ERR(tlink)) {
545 rc = PTR_ERR(tlink);
546 goto symlink_exit;
547 }
548 pTcon = tlink_tcon(tlink);
549
550 full_path = build_path_from_dentry(direntry);
551 if (full_path == NULL) {
552 rc = -ENOMEM;
553 goto symlink_exit;
554 }
555
556 cFYI(1, "Full path: %s", full_path);
557 cFYI(1, "symname is %s", symname);
558
559 /* BB what if DFS and this volume is on different share? BB */
560 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
561 rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
562 cifs_sb->local_nls,
563 cifs_sb->mnt_cifs_flags &
564 CIFS_MOUNT_MAP_SPECIAL_CHR);
565 else if (pTcon->unix_ext)
566 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
567 cifs_sb->local_nls);
568 /* else
569 rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
570 cifs_sb_target->local_nls); */
571
572 if (rc == 0) {
573 if (pTcon->unix_ext)
574 rc = cifs_get_inode_info_unix(&newinode, full_path,
575 inode->i_sb, xid);
576 else
577 rc = cifs_get_inode_info(&newinode, full_path, NULL,
578 inode->i_sb, xid, NULL);
579
580 if (rc != 0) {
581 cFYI(1, "Create symlink ok, getinodeinfo fail rc = %d",
582 rc);
583 } else {
584 d_instantiate(direntry, newinode);
585 }
586 }
587symlink_exit:
588 kfree(full_path);
589 cifs_put_tlink(tlink);
590 FreeXid(xid);
591 return rc;
592}
593
594void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
595{
596 char *p = nd_get_link(nd);
597 if (!IS_ERR(p))
598 kfree(p);
599}
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}