xattr_acl.c revision 8b6dd72a441a683cef7ace93de0a57ced4367f00 
1#include <linux/capability.h>
2#include <linux/fs.h>
3#include <linux/posix_acl.h>
4#include <linux/reiserfs_fs.h>
5#include <linux/errno.h>
6#include <linux/pagemap.h>
7#include <linux/xattr.h>
8#include <linux/posix_acl_xattr.h>
9#include <linux/reiserfs_xattr.h>
10#include <linux/reiserfs_acl.h>
11#include <asm/uaccess.h>
12
13static int reiserfs_set_acl(struct inode *inode, int type,
14			    struct posix_acl *acl);
15
16static int
17xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
18{
19	struct posix_acl *acl;
20	int error;
21
22	if (!reiserfs_posixacl(inode->i_sb))
23		return -EOPNOTSUPP;
24	if (!is_owner_or_cap(inode))
25		return -EPERM;
26
27	if (value) {
28		acl = posix_acl_from_xattr(value, size);
29		if (IS_ERR(acl)) {
30			return PTR_ERR(acl);
31		} else if (acl) {
32			error = posix_acl_valid(acl);
33			if (error)
34				goto release_and_out;
35		}
36	} else
37		acl = NULL;
38
39	error = reiserfs_set_acl(inode, type, acl);
40
41      release_and_out:
42	posix_acl_release(acl);
43	return error;
44}
45
46static int
47xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
48{
49	struct posix_acl *acl;
50	int error;
51
52	if (!reiserfs_posixacl(inode->i_sb))
53		return -EOPNOTSUPP;
54
55	acl = reiserfs_get_acl(inode, type);
56	if (IS_ERR(acl))
57		return PTR_ERR(acl);
58	if (acl == NULL)
59		return -ENODATA;
60	error = posix_acl_to_xattr(acl, buffer, size);
61	posix_acl_release(acl);
62
63	return error;
64}
65
66/*
67 * Convert from filesystem to in-memory representation.
68 */
69static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
70{
71	const char *end = (char *)value + size;
72	int n, count;
73	struct posix_acl *acl;
74
75	if (!value)
76		return NULL;
77	if (size < sizeof(reiserfs_acl_header))
78		return ERR_PTR(-EINVAL);
79	if (((reiserfs_acl_header *) value)->a_version !=
80	    cpu_to_le32(REISERFS_ACL_VERSION))
81		return ERR_PTR(-EINVAL);
82	value = (char *)value + sizeof(reiserfs_acl_header);
83	count = reiserfs_acl_count(size);
84	if (count < 0)
85		return ERR_PTR(-EINVAL);
86	if (count == 0)
87		return NULL;
88	acl = posix_acl_alloc(count, GFP_NOFS);
89	if (!acl)
90		return ERR_PTR(-ENOMEM);
91	for (n = 0; n < count; n++) {
92		reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
93		if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
94			goto fail;
95		acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
96		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
97		switch (acl->a_entries[n].e_tag) {
98		case ACL_USER_OBJ:
99		case ACL_GROUP_OBJ:
100		case ACL_MASK:
101		case ACL_OTHER:
102			value = (char *)value +
103			    sizeof(reiserfs_acl_entry_short);
104			acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
105			break;
106
107		case ACL_USER:
108		case ACL_GROUP:
109			value = (char *)value + sizeof(reiserfs_acl_entry);
110			if ((char *)value > end)
111				goto fail;
112			acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
113			break;
114
115		default:
116			goto fail;
117		}
118	}
119	if (value != end)
120		goto fail;
121	return acl;
122
123      fail:
124	posix_acl_release(acl);
125	return ERR_PTR(-EINVAL);
126}
127
128/*
129 * Convert from in-memory to filesystem representation.
130 */
131static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
132{
133	reiserfs_acl_header *ext_acl;
134	char *e;
135	int n;
136
137	*size = reiserfs_acl_size(acl->a_count);
138	ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
139						  acl->a_count *
140						  sizeof(reiserfs_acl_entry),
141						  GFP_NOFS);
142	if (!ext_acl)
143		return ERR_PTR(-ENOMEM);
144	ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
145	e = (char *)ext_acl + sizeof(reiserfs_acl_header);
146	for (n = 0; n < acl->a_count; n++) {
147		reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
148		entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
149		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
150		switch (acl->a_entries[n].e_tag) {
151		case ACL_USER:
152		case ACL_GROUP:
153			entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
154			e += sizeof(reiserfs_acl_entry);
155			break;
156
157		case ACL_USER_OBJ:
158		case ACL_GROUP_OBJ:
159		case ACL_MASK:
160		case ACL_OTHER:
161			e += sizeof(reiserfs_acl_entry_short);
162			break;
163
164		default:
165			goto fail;
166		}
167	}
168	return (char *)ext_acl;
169
170      fail:
171	kfree(ext_acl);
172	return ERR_PTR(-EINVAL);
173}
174
175static inline void iset_acl(struct inode *inode, struct posix_acl **i_acl,
176			    struct posix_acl *acl)
177{
178	spin_lock(&inode->i_lock);
179	if (*i_acl != ERR_PTR(-ENODATA))
180		posix_acl_release(*i_acl);
181	*i_acl = posix_acl_dup(acl);
182	spin_unlock(&inode->i_lock);
183}
184
185static inline struct posix_acl *iget_acl(struct inode *inode,
186					 struct posix_acl **i_acl)
187{
188	struct posix_acl *acl = ERR_PTR(-ENODATA);
189
190	spin_lock(&inode->i_lock);
191	if (*i_acl != ERR_PTR(-ENODATA))
192		acl = posix_acl_dup(*i_acl);
193	spin_unlock(&inode->i_lock);
194
195	return acl;
196}
197
198/*
199 * Inode operation get_posix_acl().
200 *
201 * inode->i_mutex: down
202 * BKL held [before 2.5.x]
203 */
204struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
205{
206	char *name, *value;
207	struct posix_acl *acl, **p_acl;
208	int size;
209	int retval;
210	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
211
212	switch (type) {
213	case ACL_TYPE_ACCESS:
214		name = POSIX_ACL_XATTR_ACCESS;
215		p_acl = &reiserfs_i->i_acl_access;
216		break;
217	case ACL_TYPE_DEFAULT:
218		name = POSIX_ACL_XATTR_DEFAULT;
219		p_acl = &reiserfs_i->i_acl_default;
220		break;
221	default:
222		return ERR_PTR(-EINVAL);
223	}
224
225	acl = iget_acl(inode, p_acl);
226	if (acl && !IS_ERR(acl))
227		return acl;
228	else if (PTR_ERR(acl) == -ENODATA)
229		return NULL;
230
231	size = reiserfs_xattr_get(inode, name, NULL, 0);
232	if (size < 0) {
233		if (size == -ENODATA || size == -ENOSYS) {
234			*p_acl = ERR_PTR(-ENODATA);
235			return NULL;
236		}
237		return ERR_PTR(size);
238	}
239
240	value = kmalloc(size, GFP_NOFS);
241	if (!value)
242		return ERR_PTR(-ENOMEM);
243
244	retval = reiserfs_xattr_get(inode, name, value, size);
245	if (retval == -ENODATA || retval == -ENOSYS) {
246		/* This shouldn't actually happen as it should have
247		   been caught above.. but just in case */
248		acl = NULL;
249		*p_acl = ERR_PTR(-ENODATA);
250	} else if (retval < 0) {
251		acl = ERR_PTR(retval);
252	} else {
253		acl = posix_acl_from_disk(value, retval);
254		if (!IS_ERR(acl))
255			iset_acl(inode, p_acl, acl);
256	}
257
258	kfree(value);
259	return acl;
260}
261
262/*
263 * Inode operation set_posix_acl().
264 *
265 * inode->i_mutex: down
266 * BKL held [before 2.5.x]
267 */
268static int
269reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
270{
271	char *name;
272	void *value = NULL;
273	struct posix_acl **p_acl;
274	size_t size;
275	int error;
276	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
277
278	if (S_ISLNK(inode->i_mode))
279		return -EOPNOTSUPP;
280
281	switch (type) {
282	case ACL_TYPE_ACCESS:
283		name = POSIX_ACL_XATTR_ACCESS;
284		p_acl = &reiserfs_i->i_acl_access;
285		if (acl) {
286			mode_t mode = inode->i_mode;
287			error = posix_acl_equiv_mode(acl, &mode);
288			if (error < 0)
289				return error;
290			else {
291				inode->i_mode = mode;
292				if (error == 0)
293					acl = NULL;
294			}
295		}
296		break;
297	case ACL_TYPE_DEFAULT:
298		name = POSIX_ACL_XATTR_DEFAULT;
299		p_acl = &reiserfs_i->i_acl_default;
300		if (!S_ISDIR(inode->i_mode))
301			return acl ? -EACCES : 0;
302		break;
303	default:
304		return -EINVAL;
305	}
306
307	if (acl) {
308		value = posix_acl_to_disk(acl, &size);
309		if (IS_ERR(value))
310			return (int)PTR_ERR(value);
311		error = reiserfs_xattr_set(inode, name, value, size, 0);
312	} else {
313		error = reiserfs_xattr_del(inode, name);
314		if (error == -ENODATA) {
315			/* This may seem odd here, but it means that the ACL was set
316			 * with a value representable with mode bits. If there was
317			 * an ACL before, reiserfs_xattr_del already dirtied the inode.
318			 */
319			mark_inode_dirty(inode);
320			error = 0;
321		}
322	}
323
324	kfree(value);
325
326	if (!error)
327		iset_acl(inode, p_acl, acl);
328
329	return error;
330}
331
332/* dir->i_mutex: locked,
333 * inode is new and not released into the wild yet */
334int
335reiserfs_inherit_default_acl(struct inode *dir, struct dentry *dentry,
336			     struct inode *inode)
337{
338	struct posix_acl *acl;
339	int err = 0;
340
341	/* ACLs only get applied to files and directories */
342	if (S_ISLNK(inode->i_mode))
343		return 0;
344
345	/* ACLs can only be used on "new" objects, so if it's an old object
346	 * there is nothing to inherit from */
347	if (get_inode_sd_version(dir) == STAT_DATA_V1)
348		goto apply_umask;
349
350	/* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
351	 * would be useless since permissions are ignored, and a pain because
352	 * it introduces locking cycles */
353	if (IS_PRIVATE(dir)) {
354		inode->i_flags |= S_PRIVATE;
355		goto apply_umask;
356	}
357
358	acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
359	if (IS_ERR(acl)) {
360		if (PTR_ERR(acl) == -ENODATA)
361			goto apply_umask;
362		return PTR_ERR(acl);
363	}
364
365	if (acl) {
366		struct posix_acl *acl_copy;
367		mode_t mode = inode->i_mode;
368		int need_acl;
369
370		/* Copy the default ACL to the default ACL of a new directory */
371		if (S_ISDIR(inode->i_mode)) {
372			err = reiserfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
373			if (err)
374				goto cleanup;
375		}
376
377		/* Now we reconcile the new ACL and the mode,
378		   potentially modifying both */
379		acl_copy = posix_acl_clone(acl, GFP_NOFS);
380		if (!acl_copy) {
381			err = -ENOMEM;
382			goto cleanup;
383		}
384
385		need_acl = posix_acl_create_masq(acl_copy, &mode);
386		if (need_acl >= 0) {
387			if (mode != inode->i_mode) {
388				inode->i_mode = mode;
389			}
390
391			/* If we need an ACL.. */
392			if (need_acl > 0) {
393				err =
394				    reiserfs_set_acl(inode, ACL_TYPE_ACCESS,
395						     acl_copy);
396				if (err)
397					goto cleanup_copy;
398			}
399		}
400	      cleanup_copy:
401		posix_acl_release(acl_copy);
402	      cleanup:
403		posix_acl_release(acl);
404	} else {
405	      apply_umask:
406		/* no ACL, apply umask */
407		inode->i_mode &= ~current->fs->umask;
408	}
409
410	return err;
411}
412
413/* Looks up and caches the result of the default ACL.
414 * We do this so that we don't need to carry the xattr_sem into
415 * reiserfs_new_inode if we don't need to */
416int reiserfs_cache_default_acl(struct inode *inode)
417{
418	int ret = 0;
419	if (reiserfs_posixacl(inode->i_sb) && !IS_PRIVATE(inode)) {
420		struct posix_acl *acl;
421		acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
422		ret = (acl && !IS_ERR(acl));
423		if (ret)
424			posix_acl_release(acl);
425	}
426
427	return ret;
428}
429
430int reiserfs_acl_chmod(struct inode *inode)
431{
432	struct posix_acl *acl, *clone;
433	int error;
434
435	if (S_ISLNK(inode->i_mode))
436		return -EOPNOTSUPP;
437
438	if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
439	    !reiserfs_posixacl(inode->i_sb)) {
440		return 0;
441	}
442
443	acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
444	if (!acl)
445		return 0;
446	if (IS_ERR(acl))
447		return PTR_ERR(acl);
448	clone = posix_acl_clone(acl, GFP_NOFS);
449	posix_acl_release(acl);
450	if (!clone)
451		return -ENOMEM;
452	error = posix_acl_chmod_masq(clone, inode->i_mode);
453	if (!error)
454		error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
455	posix_acl_release(clone);
456	return error;
457}
458
459static int
460posix_acl_access_get(struct inode *inode, const char *name,
461		     void *buffer, size_t size)
462{
463	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
464		return -EINVAL;
465	return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
466}
467
468static int
469posix_acl_access_set(struct inode *inode, const char *name,
470		     const void *value, size_t size, int flags)
471{
472	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
473		return -EINVAL;
474	return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
475}
476
477static int posix_acl_access_del(struct inode *inode, const char *name)
478{
479	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
480	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
481		return -EINVAL;
482	iset_acl(inode, &reiserfs_i->i_acl_access, ERR_PTR(-ENODATA));
483	return 0;
484}
485
486static int
487posix_acl_access_list(struct inode *inode, const char *name, int namelen,
488		      char *out)
489{
490	int len = namelen;
491	if (!reiserfs_posixacl(inode->i_sb))
492		return 0;
493	if (out)
494		memcpy(out, name, len);
495
496	return len;
497}
498
499struct reiserfs_xattr_handler posix_acl_access_handler = {
500	.prefix = POSIX_ACL_XATTR_ACCESS,
501	.get = posix_acl_access_get,
502	.set = posix_acl_access_set,
503	.del = posix_acl_access_del,
504	.list = posix_acl_access_list,
505};
506
507static int
508posix_acl_default_get(struct inode *inode, const char *name,
509		      void *buffer, size_t size)
510{
511	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
512		return -EINVAL;
513	return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
514}
515
516static int
517posix_acl_default_set(struct inode *inode, const char *name,
518		      const void *value, size_t size, int flags)
519{
520	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
521		return -EINVAL;
522	return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
523}
524
525static int posix_acl_default_del(struct inode *inode, const char *name)
526{
527	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
528	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
529		return -EINVAL;
530	iset_acl(inode, &reiserfs_i->i_acl_default, ERR_PTR(-ENODATA));
531	return 0;
532}
533
534static int
535posix_acl_default_list(struct inode *inode, const char *name, int namelen,
536		       char *out)
537{
538	int len = namelen;
539	if (!reiserfs_posixacl(inode->i_sb))
540		return 0;
541	if (out)
542		memcpy(out, name, len);
543
544	return len;
545}
546
547struct reiserfs_xattr_handler posix_acl_default_handler = {
548	.prefix = POSIX_ACL_XATTR_DEFAULT,
549	.get = posix_acl_default_get,
550	.set = posix_acl_default_set,
551	.del = posix_acl_default_del,
552	.list = posix_acl_default_list,
553};
554