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xattr.c
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1 /*
2  * fs/cifs/xattr.c
3  *
4  * Copyright (c) International Business Machines Corp., 2003, 2007
5  * Author(s): Steve French ([email protected])
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 
22 #include <linux/fs.h>
23 #include <linux/posix_acl_xattr.h>
24 #include <linux/slab.h>
25 #include <linux/xattr.h>
26 #include "cifsfs.h"
27 #include "cifspdu.h"
28 #include "cifsglob.h"
29 #include "cifsproto.h"
30 #include "cifs_debug.h"
31 
32 #define MAX_EA_VALUE_SIZE 65535
33 #define CIFS_XATTR_DOS_ATTRIB "user.DosAttrib"
34 #define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
35 
36 /* BB need to add server (Samba e.g) support for security and trusted prefix */
37 
38 int cifs_removexattr(struct dentry *direntry, const char *ea_name)
39 {
40  int rc = -EOPNOTSUPP;
41 #ifdef CONFIG_CIFS_XATTR
42  unsigned int xid;
43  struct cifs_sb_info *cifs_sb;
44  struct tcon_link *tlink;
45  struct cifs_tcon *pTcon;
46  struct super_block *sb;
47  char *full_path = NULL;
48 
49  if (direntry == NULL)
50  return -EIO;
51  if (direntry->d_inode == NULL)
52  return -EIO;
53  sb = direntry->d_inode->i_sb;
54  if (sb == NULL)
55  return -EIO;
56 
57  cifs_sb = CIFS_SB(sb);
58  tlink = cifs_sb_tlink(cifs_sb);
59  if (IS_ERR(tlink))
60  return PTR_ERR(tlink);
61  pTcon = tlink_tcon(tlink);
62 
63  xid = get_xid();
64 
65  full_path = build_path_from_dentry(direntry);
66  if (full_path == NULL) {
67  rc = -ENOMEM;
68  goto remove_ea_exit;
69  }
70  if (ea_name == NULL) {
71  cFYI(1, "Null xattr names not supported");
72  } else if (strncmp(ea_name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)
73  && (strncmp(ea_name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN))) {
74  cFYI(1,
75  "illegal xattr request %s (only user namespace supported)",
76  ea_name);
77  /* BB what if no namespace prefix? */
78  /* Should we just pass them to server, except for
79  system and perhaps security prefixes? */
80  } else {
81  if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
82  goto remove_ea_exit;
83 
84  ea_name += XATTR_USER_PREFIX_LEN; /* skip past user. prefix */
85  rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, NULL,
86  (__u16)0, cifs_sb->local_nls,
87  cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
88  }
89 remove_ea_exit:
90  kfree(full_path);
91  free_xid(xid);
92  cifs_put_tlink(tlink);
93 #endif
94  return rc;
95 }
96 
97 int cifs_setxattr(struct dentry *direntry, const char *ea_name,
98  const void *ea_value, size_t value_size, int flags)
99 {
100  int rc = -EOPNOTSUPP;
101 #ifdef CONFIG_CIFS_XATTR
102  unsigned int xid;
103  struct cifs_sb_info *cifs_sb;
104  struct tcon_link *tlink;
105  struct cifs_tcon *pTcon;
106  struct super_block *sb;
107  char *full_path;
108 
109  if (direntry == NULL)
110  return -EIO;
111  if (direntry->d_inode == NULL)
112  return -EIO;
113  sb = direntry->d_inode->i_sb;
114  if (sb == NULL)
115  return -EIO;
116 
117  cifs_sb = CIFS_SB(sb);
118  tlink = cifs_sb_tlink(cifs_sb);
119  if (IS_ERR(tlink))
120  return PTR_ERR(tlink);
121  pTcon = tlink_tcon(tlink);
122 
123  xid = get_xid();
124 
125  full_path = build_path_from_dentry(direntry);
126  if (full_path == NULL) {
127  rc = -ENOMEM;
128  goto set_ea_exit;
129  }
130  /* return dos attributes as pseudo xattr */
131  /* return alt name if available as pseudo attr */
132 
133  /* if proc/fs/cifs/streamstoxattr is set then
134  search server for EAs or streams to
135  returns as xattrs */
136  if (value_size > MAX_EA_VALUE_SIZE) {
137  cFYI(1, "size of EA value too large");
138  rc = -EOPNOTSUPP;
139  goto set_ea_exit;
140  }
141 
142  if (ea_name == NULL) {
143  cFYI(1, "Null xattr names not supported");
144  } else if (strncmp(ea_name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)
145  == 0) {
146  if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
147  goto set_ea_exit;
148  if (strncmp(ea_name, CIFS_XATTR_DOS_ATTRIB, 14) == 0)
149  cFYI(1, "attempt to set cifs inode metadata");
150 
151  ea_name += XATTR_USER_PREFIX_LEN; /* skip past user. prefix */
152  rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, ea_value,
153  (__u16)value_size, cifs_sb->local_nls,
154  cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
155  } else if (strncmp(ea_name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)
156  == 0) {
157  if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
158  goto set_ea_exit;
159 
160  ea_name += XATTR_OS2_PREFIX_LEN; /* skip past os2. prefix */
161  rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, ea_value,
162  (__u16)value_size, cifs_sb->local_nls,
163  cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
164  } else if (strncmp(ea_name, CIFS_XATTR_CIFS_ACL,
165  strlen(CIFS_XATTR_CIFS_ACL)) == 0) {
166 #ifdef CONFIG_CIFS_ACL
167  struct cifs_ntsd *pacl;
168  pacl = kmalloc(value_size, GFP_KERNEL);
169  if (!pacl) {
170  cFYI(1, "%s: Can't allocate memory for ACL",
171  __func__);
172  rc = -ENOMEM;
173  } else {
174  memcpy(pacl, ea_value, value_size);
175  rc = set_cifs_acl(pacl, value_size,
176  direntry->d_inode, full_path, CIFS_ACL_DACL);
177  if (rc == 0) /* force revalidate of the inode */
178  CIFS_I(direntry->d_inode)->time = 0;
179  kfree(pacl);
180  }
181 #else
182  cFYI(1, "Set CIFS ACL not supported yet");
183 #endif /* CONFIG_CIFS_ACL */
184  } else {
185  int temp;
186  temp = strncmp(ea_name, POSIX_ACL_XATTR_ACCESS,
187  strlen(POSIX_ACL_XATTR_ACCESS));
188  if (temp == 0) {
189 #ifdef CONFIG_CIFS_POSIX
190  if (sb->s_flags & MS_POSIXACL)
191  rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
192  ea_value, (const int)value_size,
193  ACL_TYPE_ACCESS, cifs_sb->local_nls,
194  cifs_sb->mnt_cifs_flags &
195  CIFS_MOUNT_MAP_SPECIAL_CHR);
196  cFYI(1, "set POSIX ACL rc %d", rc);
197 #else
198  cFYI(1, "set POSIX ACL not supported");
199 #endif
200  } else if (strncmp(ea_name, POSIX_ACL_XATTR_DEFAULT,
201  strlen(POSIX_ACL_XATTR_DEFAULT)) == 0) {
202 #ifdef CONFIG_CIFS_POSIX
203  if (sb->s_flags & MS_POSIXACL)
204  rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
205  ea_value, (const int)value_size,
206  ACL_TYPE_DEFAULT, cifs_sb->local_nls,
207  cifs_sb->mnt_cifs_flags &
208  CIFS_MOUNT_MAP_SPECIAL_CHR);
209  cFYI(1, "set POSIX default ACL rc %d", rc);
210 #else
211  cFYI(1, "set default POSIX ACL not supported");
212 #endif
213  } else {
214  cFYI(1, "illegal xattr request %s (only user namespace"
215  " supported)", ea_name);
216  /* BB what if no namespace prefix? */
217  /* Should we just pass them to server, except for
218  system and perhaps security prefixes? */
219  }
220  }
221 
222 set_ea_exit:
223  kfree(full_path);
224  free_xid(xid);
225  cifs_put_tlink(tlink);
226 #endif
227  return rc;
228 }
229 
230 ssize_t cifs_getxattr(struct dentry *direntry, const char *ea_name,
231  void *ea_value, size_t buf_size)
232 {
233  ssize_t rc = -EOPNOTSUPP;
234 #ifdef CONFIG_CIFS_XATTR
235  unsigned int xid;
236  struct cifs_sb_info *cifs_sb;
237  struct tcon_link *tlink;
238  struct cifs_tcon *pTcon;
239  struct super_block *sb;
240  char *full_path;
241 
242  if (direntry == NULL)
243  return -EIO;
244  if (direntry->d_inode == NULL)
245  return -EIO;
246  sb = direntry->d_inode->i_sb;
247  if (sb == NULL)
248  return -EIO;
249 
250  cifs_sb = CIFS_SB(sb);
251  tlink = cifs_sb_tlink(cifs_sb);
252  if (IS_ERR(tlink))
253  return PTR_ERR(tlink);
254  pTcon = tlink_tcon(tlink);
255 
256  xid = get_xid();
257 
258  full_path = build_path_from_dentry(direntry);
259  if (full_path == NULL) {
260  rc = -ENOMEM;
261  goto get_ea_exit;
262  }
263  /* return dos attributes as pseudo xattr */
264  /* return alt name if available as pseudo attr */
265  if (ea_name == NULL) {
266  cFYI(1, "Null xattr names not supported");
267  } else if (strncmp(ea_name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)
268  == 0) {
269  if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
270  goto get_ea_exit;
271 
272  if (strncmp(ea_name, CIFS_XATTR_DOS_ATTRIB, 14) == 0) {
273  cFYI(1, "attempt to query cifs inode metadata");
274  /* revalidate/getattr then populate from inode */
275  } /* BB add else when above is implemented */
276  ea_name += XATTR_USER_PREFIX_LEN; /* skip past user. prefix */
277  rc = CIFSSMBQAllEAs(xid, pTcon, full_path, ea_name, ea_value,
278  buf_size, cifs_sb->local_nls,
279  cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
280  } else if (strncmp(ea_name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
281  if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
282  goto get_ea_exit;
283 
284  ea_name += XATTR_OS2_PREFIX_LEN; /* skip past os2. prefix */
285  rc = CIFSSMBQAllEAs(xid, pTcon, full_path, ea_name, ea_value,
286  buf_size, cifs_sb->local_nls,
287  cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
288  } else if (strncmp(ea_name, POSIX_ACL_XATTR_ACCESS,
289  strlen(POSIX_ACL_XATTR_ACCESS)) == 0) {
290 #ifdef CONFIG_CIFS_POSIX
291  if (sb->s_flags & MS_POSIXACL)
292  rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
293  ea_value, buf_size, ACL_TYPE_ACCESS,
294  cifs_sb->local_nls,
295  cifs_sb->mnt_cifs_flags &
296  CIFS_MOUNT_MAP_SPECIAL_CHR);
297 #else
298  cFYI(1, "Query POSIX ACL not supported yet");
299 #endif /* CONFIG_CIFS_POSIX */
300  } else if (strncmp(ea_name, POSIX_ACL_XATTR_DEFAULT,
301  strlen(POSIX_ACL_XATTR_DEFAULT)) == 0) {
302 #ifdef CONFIG_CIFS_POSIX
303  if (sb->s_flags & MS_POSIXACL)
304  rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
305  ea_value, buf_size, ACL_TYPE_DEFAULT,
306  cifs_sb->local_nls,
307  cifs_sb->mnt_cifs_flags &
308  CIFS_MOUNT_MAP_SPECIAL_CHR);
309 #else
310  cFYI(1, "Query POSIX default ACL not supported yet");
311 #endif /* CONFIG_CIFS_POSIX */
312  } else if (strncmp(ea_name, CIFS_XATTR_CIFS_ACL,
313  strlen(CIFS_XATTR_CIFS_ACL)) == 0) {
314 #ifdef CONFIG_CIFS_ACL
315  u32 acllen;
316  struct cifs_ntsd *pacl;
317 
318  pacl = get_cifs_acl(cifs_sb, direntry->d_inode,
319  full_path, &acllen);
320  if (IS_ERR(pacl)) {
321  rc = PTR_ERR(pacl);
322  cERROR(1, "%s: error %zd getting sec desc",
323  __func__, rc);
324  } else {
325  if (ea_value) {
326  if (acllen > buf_size)
327  acllen = -ERANGE;
328  else
329  memcpy(ea_value, pacl, acllen);
330  }
331  rc = acllen;
332  kfree(pacl);
333  }
334 #else
335  cFYI(1, "Query CIFS ACL not supported yet");
336 #endif /* CONFIG_CIFS_ACL */
337  } else if (strncmp(ea_name,
338  XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) == 0) {
339  cFYI(1, "Trusted xattr namespace not supported yet");
340  } else if (strncmp(ea_name,
341  XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) == 0) {
342  cFYI(1, "Security xattr namespace not supported yet");
343  } else
344  cFYI(1,
345  "illegal xattr request %s (only user namespace supported)",
346  ea_name);
347 
348  /* We could add an additional check for streams ie
349  if proc/fs/cifs/streamstoxattr is set then
350  search server for EAs or streams to
351  returns as xattrs */
352 
353  if (rc == -EINVAL)
354  rc = -EOPNOTSUPP;
355 
356 get_ea_exit:
357  kfree(full_path);
358  free_xid(xid);
359  cifs_put_tlink(tlink);
360 #endif
361  return rc;
362 }
363 
364 ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
365 {
366  ssize_t rc = -EOPNOTSUPP;
367 #ifdef CONFIG_CIFS_XATTR
368  unsigned int xid;
369  struct cifs_sb_info *cifs_sb;
370  struct tcon_link *tlink;
371  struct cifs_tcon *pTcon;
372  struct super_block *sb;
373  char *full_path;
374 
375  if (direntry == NULL)
376  return -EIO;
377  if (direntry->d_inode == NULL)
378  return -EIO;
379  sb = direntry->d_inode->i_sb;
380  if (sb == NULL)
381  return -EIO;
382 
383  cifs_sb = CIFS_SB(sb);
384  if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
385  return -EOPNOTSUPP;
386 
387  tlink = cifs_sb_tlink(cifs_sb);
388  if (IS_ERR(tlink))
389  return PTR_ERR(tlink);
390  pTcon = tlink_tcon(tlink);
391 
392  xid = get_xid();
393 
394  full_path = build_path_from_dentry(direntry);
395  if (full_path == NULL) {
396  rc = -ENOMEM;
397  goto list_ea_exit;
398  }
399  /* return dos attributes as pseudo xattr */
400  /* return alt name if available as pseudo attr */
401 
402  /* if proc/fs/cifs/streamstoxattr is set then
403  search server for EAs or streams to
404  returns as xattrs */
405  rc = CIFSSMBQAllEAs(xid, pTcon, full_path, NULL, data,
406  buf_size, cifs_sb->local_nls,
407  cifs_sb->mnt_cifs_flags &
408  CIFS_MOUNT_MAP_SPECIAL_CHR);
409 
410 list_ea_exit:
411  kfree(full_path);
412  free_xid(xid);
413  cifs_put_tlink(tlink);
414 #endif
415  return rc;
416 }
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