GNU Linux-libre 6.8.7-gnu
[releases.git] / fs / smb / client / link.c
1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3  *
4  *   Copyright (C) International Business Machines  Corp., 2002,2008
5  *   Author(s): Steve French (sfrench@us.ibm.com)
6  *
7  */
8 #include <linux/fs.h>
9 #include <linux/stat.h>
10 #include <linux/slab.h>
11 #include <linux/namei.h>
12 #include "cifsfs.h"
13 #include "cifspdu.h"
14 #include "cifsglob.h"
15 #include "cifsproto.h"
16 #include "cifs_debug.h"
17 #include "cifs_fs_sb.h"
18 #include "cifs_unicode.h"
19 #include "smb2proto.h"
20 #include "cifs_ioctl.h"
21
22 /*
23  * M-F Symlink Functions - Begin
24  */
25
26 #define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
27 #define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
28 #define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
29 #define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
30 #define CIFS_MF_SYMLINK_FILE_SIZE \
31         (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
32
33 #define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
34 #define CIFS_MF_SYMLINK_MD5_FORMAT "%16phN\n"
35 #define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash
36
37 static int
38 symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash)
39 {
40         int rc;
41         struct shash_desc *md5 = NULL;
42
43         rc = cifs_alloc_hash("md5", &md5);
44         if (rc)
45                 return rc;
46
47         rc = crypto_shash_digest(md5, link_str, link_len, md5_hash);
48         if (rc)
49                 cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
50         cifs_free_hash(&md5);
51         return rc;
52 }
53
54 static int
55 parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
56                  char **_link_str)
57 {
58         int rc;
59         unsigned int link_len;
60         const char *md5_str1;
61         const char *link_str;
62         u8 md5_hash[16];
63         char md5_str2[34];
64
65         if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
66                 return -EINVAL;
67
68         md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
69         link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
70
71         rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
72         if (rc != 1)
73                 return -EINVAL;
74
75         if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
76                 return -EINVAL;
77
78         rc = symlink_hash(link_len, link_str, md5_hash);
79         if (rc) {
80                 cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc);
81                 return rc;
82         }
83
84         scnprintf(md5_str2, sizeof(md5_str2),
85                   CIFS_MF_SYMLINK_MD5_FORMAT,
86                   CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
87
88         if (strncmp(md5_str1, md5_str2, 17) != 0)
89                 return -EINVAL;
90
91         if (_link_str) {
92                 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
93                 if (!*_link_str)
94                         return -ENOMEM;
95         }
96
97         *_link_len = link_len;
98         return 0;
99 }
100
101 static int
102 format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
103 {
104         int rc;
105         unsigned int link_len;
106         unsigned int ofs;
107         u8 md5_hash[16];
108
109         if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
110                 return -EINVAL;
111
112         link_len = strlen(link_str);
113
114         if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
115                 return -ENAMETOOLONG;
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         scnprintf(buf, buf_len,
124                   CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
125                   link_len,
126                   CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
127
128         ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
129         memcpy(buf + ofs, link_str, link_len);
130
131         ofs += link_len;
132         if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
133                 buf[ofs] = '\n';
134                 ofs++;
135         }
136
137         while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
138                 buf[ofs] = ' ';
139                 ofs++;
140         }
141
142         return 0;
143 }
144
145 bool
146 couldbe_mf_symlink(const struct cifs_fattr *fattr)
147 {
148         if (!S_ISREG(fattr->cf_mode))
149                 /* it's not a symlink */
150                 return false;
151
152         if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
153                 /* it's not a symlink */
154                 return false;
155
156         return true;
157 }
158
159 static int
160 create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
161                   struct cifs_sb_info *cifs_sb, const char *fromName,
162                   const char *toName)
163 {
164         int rc;
165         u8 *buf;
166         unsigned int bytes_written = 0;
167
168         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
169         if (!buf)
170                 return -ENOMEM;
171
172         rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
173         if (rc)
174                 goto out;
175
176         if (tcon->ses->server->ops->create_mf_symlink)
177                 rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
178                                         cifs_sb, fromName, buf, &bytes_written);
179         else
180                 rc = -EOPNOTSUPP;
181
182         if (rc)
183                 goto out;
184
185         if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
186                 rc = -EIO;
187 out:
188         kfree(buf);
189         return rc;
190 }
191
192 int
193 check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
194                  struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
195                  const unsigned char *path)
196 {
197         int rc;
198         u8 *buf = NULL;
199         unsigned int link_len = 0;
200         unsigned int bytes_read = 0;
201         char *symlink = NULL;
202
203         if (!couldbe_mf_symlink(fattr))
204                 /* it's not a symlink */
205                 return 0;
206
207         buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
208         if (!buf)
209                 return -ENOMEM;
210
211         if (tcon->ses->server->ops->query_mf_symlink)
212                 rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
213                                               cifs_sb, path, buf, &bytes_read);
214         else
215                 rc = -ENOSYS;
216
217         if (rc)
218                 goto out;
219
220         if (bytes_read == 0) /* not a symlink */
221                 goto out;
222
223         rc = parse_mf_symlink(buf, bytes_read, &link_len, &symlink);
224         if (rc == -EINVAL) {
225                 /* it's not a symlink */
226                 rc = 0;
227                 goto out;
228         }
229
230         if (rc != 0)
231                 goto out;
232
233         /* it is a symlink */
234         fattr->cf_eof = link_len;
235         fattr->cf_mode &= ~S_IFMT;
236         fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
237         fattr->cf_dtype = DT_LNK;
238         fattr->cf_symlink_target = symlink;
239 out:
240         kfree(buf);
241         return rc;
242 }
243
244 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
245 /*
246  * SMB 1.0 Protocol specific functions
247  */
248
249 int
250 cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
251                       struct cifs_sb_info *cifs_sb, const unsigned char *path,
252                       char *pbuf, unsigned int *pbytes_read)
253 {
254         int rc;
255         int oplock = 0;
256         struct cifs_fid fid;
257         struct cifs_open_parms oparms;
258         struct cifs_io_parms io_parms = {0};
259         int buf_type = CIFS_NO_BUFFER;
260         FILE_ALL_INFO file_info;
261
262         oparms = (struct cifs_open_parms) {
263                 .tcon = tcon,
264                 .cifs_sb = cifs_sb,
265                 .desired_access = GENERIC_READ,
266                 .create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR),
267                 .disposition = FILE_OPEN,
268                 .path = path,
269                 .fid = &fid,
270         };
271
272         rc = CIFS_open(xid, &oparms, &oplock, &file_info);
273         if (rc)
274                 return rc;
275
276         if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
277                 rc = -ENOENT;
278                 /* it's not a symlink */
279                 goto out;
280         }
281
282         io_parms.netfid = fid.netfid;
283         io_parms.pid = current->tgid;
284         io_parms.tcon = tcon;
285         io_parms.offset = 0;
286         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
287
288         rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
289 out:
290         CIFSSMBClose(xid, tcon, fid.netfid);
291         return rc;
292 }
293
294 int
295 cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
296                        struct cifs_sb_info *cifs_sb, const unsigned char *path,
297                        char *pbuf, unsigned int *pbytes_written)
298 {
299         int rc;
300         int oplock = 0;
301         struct cifs_fid fid;
302         struct cifs_open_parms oparms;
303         struct cifs_io_parms io_parms = {0};
304
305         oparms = (struct cifs_open_parms) {
306                 .tcon = tcon,
307                 .cifs_sb = cifs_sb,
308                 .desired_access = GENERIC_WRITE,
309                 .create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR),
310                 .disposition = FILE_CREATE,
311                 .path = path,
312                 .fid = &fid,
313         };
314
315         rc = CIFS_open(xid, &oparms, &oplock, NULL);
316         if (rc)
317                 return rc;
318
319         io_parms.netfid = fid.netfid;
320         io_parms.pid = current->tgid;
321         io_parms.tcon = tcon;
322         io_parms.offset = 0;
323         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
324
325         rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf);
326         CIFSSMBClose(xid, tcon, fid.netfid);
327         return rc;
328 }
329 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
330
331 /*
332  * SMB 2.1/SMB3 Protocol specific functions
333  */
334 int
335 smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
336                       struct cifs_sb_info *cifs_sb, const unsigned char *path,
337                       char *pbuf, unsigned int *pbytes_read)
338 {
339         int rc;
340         struct cifs_fid fid;
341         struct cifs_open_parms oparms;
342         struct cifs_io_parms io_parms = {0};
343         int buf_type = CIFS_NO_BUFFER;
344         __le16 *utf16_path;
345         __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
346         struct smb2_file_all_info *pfile_info = NULL;
347
348         oparms = (struct cifs_open_parms) {
349                 .tcon = tcon,
350                 .cifs_sb = cifs_sb,
351                 .path = path,
352                 .desired_access = GENERIC_READ,
353                 .create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR),
354                 .disposition = FILE_OPEN,
355                 .fid = &fid,
356         };
357
358         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
359         if (utf16_path == NULL)
360                 return -ENOMEM;
361
362         pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
363                              GFP_KERNEL);
364
365         if (pfile_info == NULL) {
366                 kfree(utf16_path);
367                 return  -ENOMEM;
368         }
369
370         rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL,
371                        NULL, NULL);
372         if (rc)
373                 goto qmf_out_open_fail;
374
375         if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
376                 /* it's not a symlink */
377                 rc = -ENOENT; /* Is there a better rc to return? */
378                 goto qmf_out;
379         }
380
381         io_parms.netfid = fid.netfid;
382         io_parms.pid = current->tgid;
383         io_parms.tcon = tcon;
384         io_parms.offset = 0;
385         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
386         io_parms.persistent_fid = fid.persistent_fid;
387         io_parms.volatile_fid = fid.volatile_fid;
388         rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
389 qmf_out:
390         SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
391 qmf_out_open_fail:
392         kfree(utf16_path);
393         kfree(pfile_info);
394         return rc;
395 }
396
397 int
398 smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
399                        struct cifs_sb_info *cifs_sb, const unsigned char *path,
400                        char *pbuf, unsigned int *pbytes_written)
401 {
402         int rc;
403         struct cifs_fid fid;
404         struct cifs_open_parms oparms;
405         struct cifs_io_parms io_parms = {0};
406         __le16 *utf16_path;
407         __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
408         struct kvec iov[2];
409
410         cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
411
412         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
413         if (!utf16_path)
414                 return -ENOMEM;
415
416         oparms = (struct cifs_open_parms) {
417                 .tcon = tcon,
418                 .cifs_sb = cifs_sb,
419                 .path = path,
420                 .desired_access = GENERIC_WRITE,
421                 .create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR),
422                 .disposition = FILE_CREATE,
423                 .fid = &fid,
424                 .mode = 0644,
425         };
426
427         rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL,
428                        NULL, NULL);
429         if (rc) {
430                 kfree(utf16_path);
431                 return rc;
432         }
433
434         io_parms.netfid = fid.netfid;
435         io_parms.pid = current->tgid;
436         io_parms.tcon = tcon;
437         io_parms.offset = 0;
438         io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
439         io_parms.persistent_fid = fid.persistent_fid;
440         io_parms.volatile_fid = fid.volatile_fid;
441
442         /* iov[0] is reserved for smb header */
443         iov[1].iov_base = pbuf;
444         iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE;
445
446         rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1);
447
448         /* Make sure we wrote all of the symlink data */
449         if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE))
450                 rc = -EIO;
451
452         SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
453
454         kfree(utf16_path);
455         return rc;
456 }
457
458 /*
459  * M-F Symlink Functions - End
460  */
461
462 int
463 cifs_hardlink(struct dentry *old_file, struct inode *inode,
464               struct dentry *direntry)
465 {
466         int rc = -EACCES;
467         unsigned int xid;
468         const char *from_name, *to_name;
469         void *page1, *page2;
470         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
471         struct tcon_link *tlink;
472         struct cifs_tcon *tcon;
473         struct TCP_Server_Info *server;
474         struct cifsInodeInfo *cifsInode;
475
476         if (unlikely(cifs_forced_shutdown(cifs_sb)))
477                 return -EIO;
478
479         tlink = cifs_sb_tlink(cifs_sb);
480         if (IS_ERR(tlink))
481                 return PTR_ERR(tlink);
482         tcon = tlink_tcon(tlink);
483
484         xid = get_xid();
485         page1 = alloc_dentry_path();
486         page2 = alloc_dentry_path();
487
488         from_name = build_path_from_dentry(old_file, page1);
489         if (IS_ERR(from_name)) {
490                 rc = PTR_ERR(from_name);
491                 goto cifs_hl_exit;
492         }
493         to_name = build_path_from_dentry(direntry, page2);
494         if (IS_ERR(to_name)) {
495                 rc = PTR_ERR(to_name);
496                 goto cifs_hl_exit;
497         }
498
499 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
500         if (tcon->unix_ext)
501                 rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
502                                             cifs_sb->local_nls,
503                                             cifs_remap(cifs_sb));
504         else {
505 #else
506         {
507 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
508                 server = tcon->ses->server;
509                 if (!server->ops->create_hardlink) {
510                         rc = -ENOSYS;
511                         goto cifs_hl_exit;
512                 }
513                 rc = server->ops->create_hardlink(xid, tcon, old_file,
514                                                   from_name, to_name, cifs_sb);
515                 if ((rc == -EIO) || (rc == -EINVAL))
516                         rc = -EOPNOTSUPP;
517         }
518
519         d_drop(direntry);       /* force new lookup from server of target */
520
521         /*
522          * if source file is cached (oplocked) revalidate will not go to server
523          * until the file is closed or oplock broken so update nlinks locally
524          */
525         if (d_really_is_positive(old_file)) {
526                 cifsInode = CIFS_I(d_inode(old_file));
527                 if (rc == 0) {
528                         spin_lock(&d_inode(old_file)->i_lock);
529                         inc_nlink(d_inode(old_file));
530                         spin_unlock(&d_inode(old_file)->i_lock);
531
532                         /*
533                          * parent dir timestamps will update from srv within a
534                          * second, would it really be worth it to set the parent
535                          * dir cifs inode time to zero to force revalidate
536                          * (faster) for it too?
537                          */
538                 }
539                 /*
540                  * if not oplocked will force revalidate to get info on source
541                  * file from srv.  Note Samba server prior to 4.2 has bug -
542                  * not updating src file ctime on hardlinks but Windows servers
543                  * handle it properly
544                  */
545                 cifsInode->time = 0;
546
547                 /*
548                  * Will update parent dir timestamps from srv within a second.
549                  * Would it really be worth it to set the parent dir (cifs
550                  * inode) time field to zero to force revalidate on parent
551                  * directory faster ie
552                  *
553                  * CIFS_I(inode)->time = 0;
554                  */
555         }
556
557 cifs_hl_exit:
558         free_dentry_path(page1);
559         free_dentry_path(page2);
560         free_xid(xid);
561         cifs_put_tlink(tlink);
562         return rc;
563 }
564
565 int
566 cifs_symlink(struct mnt_idmap *idmap, struct inode *inode,
567              struct dentry *direntry, const char *symname)
568 {
569         int rc = -EOPNOTSUPP;
570         unsigned int xid;
571         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
572         struct TCP_Server_Info *server;
573         struct tcon_link *tlink;
574         struct cifs_tcon *pTcon;
575         const char *full_path;
576         void *page;
577         struct inode *newinode = NULL;
578
579         if (unlikely(cifs_forced_shutdown(cifs_sb)))
580                 return -EIO;
581
582         page = alloc_dentry_path();
583         if (!page)
584                 return -ENOMEM;
585
586         xid = get_xid();
587
588         tlink = cifs_sb_tlink(cifs_sb);
589         if (IS_ERR(tlink)) {
590                 rc = PTR_ERR(tlink);
591                 goto symlink_exit;
592         }
593         pTcon = tlink_tcon(tlink);
594         server = cifs_pick_channel(pTcon->ses);
595
596         full_path = build_path_from_dentry(direntry, page);
597         if (IS_ERR(full_path)) {
598                 rc = PTR_ERR(full_path);
599                 goto symlink_exit;
600         }
601
602         cifs_dbg(FYI, "Full path: %s\n", full_path);
603         cifs_dbg(FYI, "symname is %s\n", symname);
604
605         /* BB what if DFS and this volume is on different share? BB */
606         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
607                 rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
608 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
609         } else if (pTcon->unix_ext) {
610                 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
611                                            cifs_sb->local_nls,
612                                            cifs_remap(cifs_sb));
613 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
614         } else if (server->ops->create_reparse_symlink) {
615                 rc =  server->ops->create_reparse_symlink(xid, inode, direntry,
616                                                           pTcon, full_path,
617                                                           symname);
618                 goto symlink_exit;
619         }
620
621         if (rc == 0) {
622                 if (pTcon->posix_extensions) {
623                         rc = smb311_posix_get_inode_info(&newinode, full_path,
624                                                          NULL, inode->i_sb, xid);
625                 } else if (pTcon->unix_ext) {
626                         rc = cifs_get_inode_info_unix(&newinode, full_path,
627                                                       inode->i_sb, xid);
628                 } else {
629                         rc = cifs_get_inode_info(&newinode, full_path, NULL,
630                                                  inode->i_sb, xid, NULL);
631                 }
632
633                 if (rc != 0) {
634                         cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
635                                  rc);
636                 } else {
637                         d_instantiate(direntry, newinode);
638                 }
639         }
640 symlink_exit:
641         free_dentry_path(page);
642         cifs_put_tlink(tlink);
643         free_xid(xid);
644         return rc;
645 }