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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/*
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#include "cifs_unicode.h"
32#ifdef CONFIG_CIFS_SMB2
33#include "smb2proto.h"
34#endif
35
36/*
37 * M-F Symlink Functions - Begin
38 */
39
40#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
41#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
42#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
43#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
44#define CIFS_MF_SYMLINK_FILE_SIZE \
45 (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
46
47#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
48#define CIFS_MF_SYMLINK_MD5_FORMAT "%16phN\n"
49#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash
50
51static int
52symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
53{
54 int rc;
55 unsigned int size;
56 struct crypto_shash *md5;
57 struct sdesc *sdescmd5;
58
59 md5 = crypto_alloc_shash("md5", 0, 0);
60 if (IS_ERR(md5)) {
61 rc = PTR_ERR(md5);
62 cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n",
63 __func__, rc);
64 return rc;
65 }
66 size = sizeof(struct shash_desc) + crypto_shash_descsize(md5);
67 sdescmd5 = kmalloc(size, GFP_KERNEL);
68 if (!sdescmd5) {
69 rc = -ENOMEM;
70 goto symlink_hash_err;
71 }
72 sdescmd5->shash.tfm = md5;
73 sdescmd5->shash.flags = 0x0;
74
75 rc = crypto_shash_init(&sdescmd5->shash);
76 if (rc) {
77 cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__);
78 goto symlink_hash_err;
79 }
80 rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len);
81 if (rc) {
82 cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
83 goto symlink_hash_err;
84 }
85 rc = crypto_shash_final(&sdescmd5->shash, md5_hash);
86 if (rc)
87 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
88
89symlink_hash_err:
90 crypto_free_shash(md5);
91 kfree(sdescmd5);
92
93 return rc;
94}
95
96static int
97parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
98 char **_link_str)
99{
100 int rc;
101 unsigned int link_len;
102 const char *md5_str1;
103 const char *link_str;
104 u8 md5_hash[16];
105 char md5_str2[34];
106
107 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
108 return -EINVAL;
109
110 md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
111 link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
112
113 rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
114 if (rc != 1)
115 return -EINVAL;
116
117 rc = symlink_hash(link_len, link_str, md5_hash);
118 if (rc) {
119 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
120 return rc;
121 }
122
123 snprintf(md5_str2, sizeof(md5_str2),
124 CIFS_MF_SYMLINK_MD5_FORMAT,
125 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
126
127 if (strncmp(md5_str1, md5_str2, 17) != 0)
128 return -EINVAL;
129
130 if (_link_str) {
131 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
132 if (!*_link_str)
133 return -ENOMEM;
134 }
135
136 *_link_len = link_len;
137 return 0;
138}
139
140static int
141format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
142{
143 int rc;
144 unsigned int link_len;
145 unsigned int ofs;
146 u8 md5_hash[16];
147
148 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
149 return -EINVAL;
150
151 link_len = strlen(link_str);
152
153 if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
154 return -ENAMETOOLONG;
155
156 rc = symlink_hash(link_len, link_str, md5_hash);
157 if (rc) {
158 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
159 return rc;
160 }
161
162 snprintf(buf, buf_len,
163 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
164 link_len,
165 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
166
167 ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
168 memcpy(buf + ofs, link_str, link_len);
169
170 ofs += link_len;
171 if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
172 buf[ofs] = '\n';
173 ofs++;
174 }
175
176 while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
177 buf[ofs] = ' ';
178 ofs++;
179 }
180
181 return 0;
182}
183
184bool
185couldbe_mf_symlink(const struct cifs_fattr *fattr)
186{
187 if (!S_ISREG(fattr->cf_mode))
188 /* it's not a symlink */
189 return false;
190
191 if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
192 /* it's not a symlink */
193 return false;
194
195 return true;
196}
197
198static int
199create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
200 struct cifs_sb_info *cifs_sb, const char *fromName,
201 const char *toName)
202{
203 int rc;
204 u8 *buf;
205 unsigned int bytes_written = 0;
206
207 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
208 if (!buf)
209 return -ENOMEM;
210
211 rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
212 if (rc)
213 goto out;
214
215 if (tcon->ses->server->ops->create_mf_symlink)
216 rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
217 cifs_sb, fromName, buf, &bytes_written);
218 else
219 rc = -EOPNOTSUPP;
220
221 if (rc)
222 goto out;
223
224 if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
225 rc = -EIO;
226out:
227 kfree(buf);
228 return rc;
229}
230
231static int
232query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
233 struct cifs_sb_info *cifs_sb, const unsigned char *path,
234 char **symlinkinfo)
235{
236 int rc;
237 u8 *buf = NULL;
238 unsigned int link_len = 0;
239 unsigned int bytes_read = 0;
240
241 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
242 if (!buf)
243 return -ENOMEM;
244
245 if (tcon->ses->server->ops->query_mf_symlink)
246 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
247 cifs_sb, path, buf, &bytes_read);
248 else
249 rc = -ENOSYS;
250
251 if (rc)
252 goto out;
253
254 if (bytes_read == 0) { /* not a symlink */
255 rc = -EINVAL;
256 goto out;
257 }
258
259 rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo);
260out:
261 kfree(buf);
262 return rc;
263}
264
265int
266check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
267 struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
268 const unsigned char *path)
269{
270 int rc;
271 u8 *buf = NULL;
272 unsigned int link_len = 0;
273 unsigned int bytes_read = 0;
274
275 if (!couldbe_mf_symlink(fattr))
276 /* it's not a symlink */
277 return 0;
278
279 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
280 if (!buf)
281 return -ENOMEM;
282
283 if (tcon->ses->server->ops->query_mf_symlink)
284 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
285 cifs_sb, path, buf, &bytes_read);
286 else
287 rc = -ENOSYS;
288
289 if (rc)
290 goto out;
291
292 if (bytes_read == 0) /* not a symlink */
293 goto out;
294
295 rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL);
296 if (rc == -EINVAL) {
297 /* it's not a symlink */
298 rc = 0;
299 goto out;
300 }
301
302 if (rc != 0)
303 goto out;
304
305 /* it is a symlink */
306 fattr->cf_eof = link_len;
307 fattr->cf_mode &= ~S_IFMT;
308 fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
309 fattr->cf_dtype = DT_LNK;
310out:
311 kfree(buf);
312 return rc;
313}
314
315/*
316 * SMB 1.0 Protocol specific functions
317 */
318
319int
320cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
321 struct cifs_sb_info *cifs_sb, const unsigned char *path,
322 char *pbuf, unsigned int *pbytes_read)
323{
324 int rc;
325 int oplock = 0;
326 struct cifs_fid fid;
327 struct cifs_open_parms oparms;
328 struct cifs_io_parms io_parms;
329 int buf_type = CIFS_NO_BUFFER;
330 FILE_ALL_INFO file_info;
331
332 oparms.tcon = tcon;
333 oparms.cifs_sb = cifs_sb;
334 oparms.desired_access = GENERIC_READ;
335 oparms.create_options = CREATE_NOT_DIR;
336 oparms.disposition = FILE_OPEN;
337 oparms.path = path;
338 oparms.fid = &fid;
339 oparms.reconnect = false;
340
341 rc = CIFS_open(xid, &oparms, &oplock, &file_info);
342 if (rc)
343 return rc;
344
345 if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
346 rc = -ENOENT;
347 /* it's not a symlink */
348 goto out;
349 }
350
351 io_parms.netfid = fid.netfid;
352 io_parms.pid = current->tgid;
353 io_parms.tcon = tcon;
354 io_parms.offset = 0;
355 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
356
357 rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
358out:
359 CIFSSMBClose(xid, tcon, fid.netfid);
360 return rc;
361}
362
363int
364cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
365 struct cifs_sb_info *cifs_sb, const unsigned char *path,
366 char *pbuf, unsigned int *pbytes_written)
367{
368 int rc;
369 int oplock = 0;
370 struct cifs_fid fid;
371 struct cifs_open_parms oparms;
372 struct cifs_io_parms io_parms;
373 int create_options = CREATE_NOT_DIR;
374
375 if (backup_cred(cifs_sb))
376 create_options |= CREATE_OPEN_BACKUP_INTENT;
377
378 oparms.tcon = tcon;
379 oparms.cifs_sb = cifs_sb;
380 oparms.desired_access = GENERIC_WRITE;
381 oparms.create_options = create_options;
382 oparms.disposition = FILE_CREATE;
383 oparms.path = path;
384 oparms.fid = &fid;
385 oparms.reconnect = false;
386
387 rc = CIFS_open(xid, &oparms, &oplock, NULL);
388 if (rc)
389 return rc;
390
391 io_parms.netfid = fid.netfid;
392 io_parms.pid = current->tgid;
393 io_parms.tcon = tcon;
394 io_parms.offset = 0;
395 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
396
397 rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf);
398 CIFSSMBClose(xid, tcon, fid.netfid);
399 return rc;
400}
401
402/*
403 * SMB 2.1/SMB3 Protocol specific functions
404 */
405#ifdef CONFIG_CIFS_SMB2
406int
407smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
408 struct cifs_sb_info *cifs_sb, const unsigned char *path,
409 char *pbuf, unsigned int *pbytes_read)
410{
411 int rc;
412 struct cifs_fid fid;
413 struct cifs_open_parms oparms;
414 struct cifs_io_parms io_parms;
415 int buf_type = CIFS_NO_BUFFER;
416 __le16 *utf16_path;
417 __u8 oplock = SMB2_OPLOCK_LEVEL_II;
418 struct smb2_file_all_info *pfile_info = NULL;
419
420 oparms.tcon = tcon;
421 oparms.cifs_sb = cifs_sb;
422 oparms.desired_access = GENERIC_READ;
423 oparms.create_options = CREATE_NOT_DIR;
424 if (backup_cred(cifs_sb))
425 oparms.create_options |= CREATE_OPEN_BACKUP_INTENT;
426 oparms.disposition = FILE_OPEN;
427 oparms.fid = &fid;
428 oparms.reconnect = false;
429
430 utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
431 if (utf16_path == NULL)
432 return -ENOMEM;
433
434 pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
435 GFP_KERNEL);
436
437 if (pfile_info == NULL) {
438 kfree(utf16_path);
439 return -ENOMEM;
440 }
441
442 rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL);
443 if (rc)
444 goto qmf_out_open_fail;
445
446 if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
447 /* it's not a symlink */
448 rc = -ENOENT; /* Is there a better rc to return? */
449 goto qmf_out;
450 }
451
452 io_parms.netfid = fid.netfid;
453 io_parms.pid = current->tgid;
454 io_parms.tcon = tcon;
455 io_parms.offset = 0;
456 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
457 io_parms.persistent_fid = fid.persistent_fid;
458 io_parms.volatile_fid = fid.volatile_fid;
459 rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
460qmf_out:
461 SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
462qmf_out_open_fail:
463 kfree(utf16_path);
464 kfree(pfile_info);
465 return rc;
466}
467
468int
469smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
470 struct cifs_sb_info *cifs_sb, const unsigned char *path,
471 char *pbuf, unsigned int *pbytes_written)
472{
473 int rc;
474 struct cifs_fid fid;
475 struct cifs_open_parms oparms;
476 struct cifs_io_parms io_parms;
477 int create_options = CREATE_NOT_DIR;
478 __le16 *utf16_path;
479 __u8 oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE;
480 struct kvec iov[2];
481
482 if (backup_cred(cifs_sb))
483 create_options |= CREATE_OPEN_BACKUP_INTENT;
484
485 cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
486
487 utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
488 if (!utf16_path)
489 return -ENOMEM;
490
491 oparms.tcon = tcon;
492 oparms.cifs_sb = cifs_sb;
493 oparms.desired_access = GENERIC_WRITE;
494 oparms.create_options = create_options;
495 oparms.disposition = FILE_CREATE;
496 oparms.fid = &fid;
497 oparms.reconnect = false;
498
499 rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
500 if (rc) {
501 kfree(utf16_path);
502 return rc;
503 }
504
505 io_parms.netfid = fid.netfid;
506 io_parms.pid = current->tgid;
507 io_parms.tcon = tcon;
508 io_parms.offset = 0;
509 io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
510 io_parms.persistent_fid = fid.persistent_fid;
511 io_parms.volatile_fid = fid.volatile_fid;
512
513 /* iov[0] is reserved for smb header */
514 iov[1].iov_base = pbuf;
515 iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE;
516
517 rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1);
518
519 /* Make sure we wrote all of the symlink data */
520 if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE))
521 rc = -EIO;
522
523 SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
524
525 kfree(utf16_path);
526 return rc;
527}
528#endif /* CONFIG_CIFS_SMB2 */
529
530/*
531 * M-F Symlink Functions - End
532 */
533
534int
535cifs_hardlink(struct dentry *old_file, struct inode *inode,
536 struct dentry *direntry)
537{
538 int rc = -EACCES;
539 unsigned int xid;
540 char *from_name = NULL;
541 char *to_name = NULL;
542 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
543 struct tcon_link *tlink;
544 struct cifs_tcon *tcon;
545 struct TCP_Server_Info *server;
546 struct cifsInodeInfo *cifsInode;
547
548 tlink = cifs_sb_tlink(cifs_sb);
549 if (IS_ERR(tlink))
550 return PTR_ERR(tlink);
551 tcon = tlink_tcon(tlink);
552
553 xid = get_xid();
554
555 from_name = build_path_from_dentry(old_file);
556 to_name = build_path_from_dentry(direntry);
557 if ((from_name == NULL) || (to_name == NULL)) {
558 rc = -ENOMEM;
559 goto cifs_hl_exit;
560 }
561
562 if (tcon->unix_ext)
563 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
564 cifs_sb->local_nls,
565 cifs_remap(cifs_sb));
566 else {
567 server = tcon->ses->server;
568 if (!server->ops->create_hardlink) {
569 rc = -ENOSYS;
570 goto cifs_hl_exit;
571 }
572 rc = server->ops->create_hardlink(xid, tcon, from_name, to_name,
573 cifs_sb);
574 if ((rc == -EIO) || (rc == -EINVAL))
575 rc = -EOPNOTSUPP;
576 }
577
578 d_drop(direntry); /* force new lookup from server of target */
579
580 /*
581 * if source file is cached (oplocked) revalidate will not go to server
582 * until the file is closed or oplock broken so update nlinks locally
583 */
584 if (d_really_is_positive(old_file)) {
585 cifsInode = CIFS_I(d_inode(old_file));
586 if (rc == 0) {
587 spin_lock(&d_inode(old_file)->i_lock);
588 inc_nlink(d_inode(old_file));
589 spin_unlock(&d_inode(old_file)->i_lock);
590
591 /*
592 * parent dir timestamps will update from srv within a
593 * second, would it really be worth it to set the parent
594 * dir cifs inode time to zero to force revalidate
595 * (faster) for it too?
596 */
597 }
598 /*
599 * if not oplocked will force revalidate to get info on source
600 * file from srv. Note Samba server prior to 4.2 has bug -
601 * not updating src file ctime on hardlinks but Windows servers
602 * handle it properly
603 */
604 cifsInode->time = 0;
605
606 /*
607 * Will update parent dir timestamps from srv within a second.
608 * Would it really be worth it to set the parent dir (cifs
609 * inode) time field to zero to force revalidate on parent
610 * directory faster ie
611 *
612 * CIFS_I(inode)->time = 0;
613 */
614 }
615
616cifs_hl_exit:
617 kfree(from_name);
618 kfree(to_name);
619 free_xid(xid);
620 cifs_put_tlink(tlink);
621 return rc;
622}
623
624const char *
625cifs_get_link(struct dentry *direntry, struct inode *inode,
626 struct delayed_call *done)
627{
628 int rc = -ENOMEM;
629 unsigned int xid;
630 char *full_path = NULL;
631 char *target_path = NULL;
632 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
633 struct tcon_link *tlink = NULL;
634 struct cifs_tcon *tcon;
635 struct TCP_Server_Info *server;
636
637 if (!direntry)
638 return ERR_PTR(-ECHILD);
639
640 xid = get_xid();
641
642 tlink = cifs_sb_tlink(cifs_sb);
643 if (IS_ERR(tlink)) {
644 free_xid(xid);
645 return ERR_CAST(tlink);
646 }
647 tcon = tlink_tcon(tlink);
648 server = tcon->ses->server;
649
650 full_path = build_path_from_dentry(direntry);
651 if (!full_path) {
652 free_xid(xid);
653 cifs_put_tlink(tlink);
654 return ERR_PTR(-ENOMEM);
655 }
656
657 cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode);
658
659 rc = -EACCES;
660 /*
661 * First try Minshall+French Symlinks, if configured
662 * and fallback to UNIX Extensions Symlinks.
663 */
664 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
665 rc = query_mf_symlink(xid, tcon, cifs_sb, full_path,
666 &target_path);
667
668 if (rc != 0 && server->ops->query_symlink)
669 rc = server->ops->query_symlink(xid, tcon, full_path,
670 &target_path, cifs_sb);
671
672 kfree(full_path);
673 free_xid(xid);
674 cifs_put_tlink(tlink);
675 if (rc != 0) {
676 kfree(target_path);
677 return ERR_PTR(rc);
678 }
679 set_delayed_call(done, kfree_link, target_path);
680 return target_path;
681}
682
683int
684cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
685{
686 int rc = -EOPNOTSUPP;
687 unsigned int xid;
688 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
689 struct tcon_link *tlink;
690 struct cifs_tcon *pTcon;
691 char *full_path = NULL;
692 struct inode *newinode = NULL;
693
694 xid = get_xid();
695
696 tlink = cifs_sb_tlink(cifs_sb);
697 if (IS_ERR(tlink)) {
698 rc = PTR_ERR(tlink);
699 goto symlink_exit;
700 }
701 pTcon = tlink_tcon(tlink);
702
703 full_path = build_path_from_dentry(direntry);
704 if (full_path == NULL) {
705 rc = -ENOMEM;
706 goto symlink_exit;
707 }
708
709 cifs_dbg(FYI, "Full path: %s\n", full_path);
710 cifs_dbg(FYI, "symname is %s\n", symname);
711
712 /* BB what if DFS and this volume is on different share? BB */
713 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
714 rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
715 else if (pTcon->unix_ext)
716 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
717 cifs_sb->local_nls,
718 cifs_remap(cifs_sb));
719 /* else
720 rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
721 cifs_sb_target->local_nls); */
722
723 if (rc == 0) {
724 if (pTcon->unix_ext)
725 rc = cifs_get_inode_info_unix(&newinode, full_path,
726 inode->i_sb, xid);
727 else
728 rc = cifs_get_inode_info(&newinode, full_path, NULL,
729 inode->i_sb, xid, NULL);
730
731 if (rc != 0) {
732 cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
733 rc);
734 } else {
735 d_instantiate(direntry, newinode);
736 }
737 }
738symlink_exit:
739 kfree(full_path);
740 cifs_put_tlink(tlink);
741 free_xid(xid);
742 return rc;
743}