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 ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
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
175/*
176 * Inode operation get_posix_acl().
177 *
178 * inode->i_mutex: down
179 * BKL held [before 2.5.x]
180 */
181struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
182{
183	char *name, *value;
184	struct posix_acl *acl, **p_acl;
185	int size;
186	int retval;
187	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
188
189	switch (type) {
190	case ACL_TYPE_ACCESS:
191		name = POSIX_ACL_XATTR_ACCESS;
192		p_acl = &reiserfs_i->i_acl_access;
193		break;
194	case ACL_TYPE_DEFAULT:
195		name = POSIX_ACL_XATTR_DEFAULT;
196		p_acl = &reiserfs_i->i_acl_default;
197		break;
198	default:
199		return ERR_PTR(-EINVAL);
200	}
201
202	if (IS_ERR(*p_acl)) {
203		if (PTR_ERR(*p_acl) == -ENODATA)
204			return NULL;
205	} else if (*p_acl != NULL)
206		return posix_acl_dup(*p_acl);
207
208	size = reiserfs_xattr_get(inode, name, NULL, 0);
209	if (size < 0) {
210		if (size == -ENODATA || size == -ENOSYS) {
211			*p_acl = ERR_PTR(-ENODATA);
212			return NULL;
213		}
214		return ERR_PTR(size);
215	}
216
217	value = kmalloc(size, GFP_NOFS);
218	if (!value)
219		return ERR_PTR(-ENOMEM);
220
221	retval = reiserfs_xattr_get(inode, name, value, size);
222	if (retval == -ENODATA || retval == -ENOSYS) {
223		/* This shouldn't actually happen as it should have
224		   been caught above.. but just in case */
225		acl = NULL;
226		*p_acl = ERR_PTR(-ENODATA);
227	} else if (retval < 0) {
228		acl = ERR_PTR(retval);
229	} else {
230		acl = posix_acl_from_disk(value, retval);
231		if (!IS_ERR(acl))
232			*p_acl = posix_acl_dup(acl);
233	}
234
235	kfree(value);
236	return acl;
237}
238
239/*
240 * Inode operation set_posix_acl().
241 *
242 * inode->i_mutex: down
243 * BKL held [before 2.5.x]
244 */
245static int
246reiserfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
247{
248	char *name;
249	void *value = NULL;
250	struct posix_acl **p_acl;
251	size_t size;
252	int error;
253	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
254
255	if (S_ISLNK(inode->i_mode))
256		return -EOPNOTSUPP;
257
258	switch (type) {
259	case ACL_TYPE_ACCESS:
260		name = POSIX_ACL_XATTR_ACCESS;
261		p_acl = &reiserfs_i->i_acl_access;
262		if (acl) {
263			mode_t mode = inode->i_mode;
264			error = posix_acl_equiv_mode(acl, &mode);
265			if (error < 0)
266				return error;
267			else {
268				inode->i_mode = mode;
269				if (error == 0)
270					acl = NULL;
271			}
272		}
273		break;
274	case ACL_TYPE_DEFAULT:
275		name = POSIX_ACL_XATTR_DEFAULT;
276		p_acl = &reiserfs_i->i_acl_default;
277		if (!S_ISDIR(inode->i_mode))
278			return acl ? -EACCES : 0;
279		break;
280	default:
281		return -EINVAL;
282	}
283
284	if (acl) {
285		value = posix_acl_to_disk(acl, &size);
286		if (IS_ERR(value))
287			return (int)PTR_ERR(value);
288		error = reiserfs_xattr_set(inode, name, value, size, 0);
289	} else {
290		error = reiserfs_xattr_del(inode, name);
291		if (error == -ENODATA) {
292			/* This may seem odd here, but it means that the ACL was set
293			 * with a value representable with mode bits. If there was
294			 * an ACL before, reiserfs_xattr_del already dirtied the inode.
295			 */
296			mark_inode_dirty(inode);
297			error = 0;
298		}
299	}
300
301	kfree(value);
302
303	if (!error) {
304		/* Release the old one */
305		if (!IS_ERR(*p_acl) && *p_acl)
306			posix_acl_release(*p_acl);
307
308		if (acl == NULL)
309			*p_acl = ERR_PTR(-ENODATA);
310		else
311			*p_acl = posix_acl_dup(acl);
312	}
313
314	return error;
315}
316
317/* dir->i_mutex: locked,
318 * inode is new and not released into the wild yet */
319int
320reiserfs_inherit_default_acl(struct inode *dir, struct dentry *dentry,
321			     struct inode *inode)
322{
323	struct posix_acl *acl;
324	int err = 0;
325
326	/* ACLs only get applied to files and directories */
327	if (S_ISLNK(inode->i_mode))
328		return 0;
329
330	/* ACLs can only be used on "new" objects, so if it's an old object
331	 * there is nothing to inherit from */
332	if (get_inode_sd_version(dir) == STAT_DATA_V1)
333		goto apply_umask;
334
335	/* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
336	 * would be useless since permissions are ignored, and a pain because
337	 * it introduces locking cycles */
338	if (is_reiserfs_priv_object(dir)) {
339		reiserfs_mark_inode_private(inode);
340		goto apply_umask;
341	}
342
343	acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
344	if (IS_ERR(acl)) {
345		if (PTR_ERR(acl) == -ENODATA)
346			goto apply_umask;
347		return PTR_ERR(acl);
348	}
349
350	if (acl) {
351		struct posix_acl *acl_copy;
352		mode_t mode = inode->i_mode;
353		int need_acl;
354
355		/* Copy the default ACL to the default ACL of a new directory */
356		if (S_ISDIR(inode->i_mode)) {
357			err = reiserfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
358			if (err)
359				goto cleanup;
360		}
361
362		/* Now we reconcile the new ACL and the mode,
363		   potentially modifying both */
364		acl_copy = posix_acl_clone(acl, GFP_NOFS);
365		if (!acl_copy) {
366			err = -ENOMEM;
367			goto cleanup;
368		}
369
370		need_acl = posix_acl_create_masq(acl_copy, &mode);
371		if (need_acl >= 0) {
372			if (mode != inode->i_mode) {
373				inode->i_mode = mode;
374			}
375
376			/* If we need an ACL.. */
377			if (need_acl > 0) {
378				err =
379				    reiserfs_set_acl(inode, ACL_TYPE_ACCESS,
380						     acl_copy);
381				if (err)
382					goto cleanup_copy;
383			}
384		}
385	      cleanup_copy:
386		posix_acl_release(acl_copy);
387	      cleanup:
388		posix_acl_release(acl);
389	} else {
390	      apply_umask:
391		/* no ACL, apply umask */
392		inode->i_mode &= ~current->fs->umask;
393	}
394
395	return err;
396}
397
398/* Looks up and caches the result of the default ACL.
399 * We do this so that we don't need to carry the xattr_sem into
400 * reiserfs_new_inode if we don't need to */
401int reiserfs_cache_default_acl(struct inode *inode)
402{
403	int ret = 0;
404	if (reiserfs_posixacl(inode->i_sb) && !is_reiserfs_priv_object(inode)) {
405		struct posix_acl *acl;
406		reiserfs_read_lock_xattr_i(inode);
407		reiserfs_read_lock_xattrs(inode->i_sb);
408		acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
409		reiserfs_read_unlock_xattrs(inode->i_sb);
410		reiserfs_read_unlock_xattr_i(inode);
411		ret = (acl && !IS_ERR(acl));
412		if (ret)
413			posix_acl_release(acl);
414	}
415
416	return ret;
417}
418
419int reiserfs_acl_chmod(struct inode *inode)
420{
421	struct posix_acl *acl, *clone;
422	int error;
423
424	if (S_ISLNK(inode->i_mode))
425		return -EOPNOTSUPP;
426
427	if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
428	    !reiserfs_posixacl(inode->i_sb)) {
429		return 0;
430	}
431
432	reiserfs_read_lock_xattrs(inode->i_sb);
433	acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
434	reiserfs_read_unlock_xattrs(inode->i_sb);
435	if (!acl)
436		return 0;
437	if (IS_ERR(acl))
438		return PTR_ERR(acl);
439	clone = posix_acl_clone(acl, GFP_NOFS);
440	posix_acl_release(acl);
441	if (!clone)
442		return -ENOMEM;
443	error = posix_acl_chmod_masq(clone, inode->i_mode);
444	if (!error) {
445		int lock = !has_xattr_dir(inode);
446		reiserfs_write_lock_xattr_i(inode);
447		if (lock)
448			reiserfs_write_lock_xattrs(inode->i_sb);
449		else
450			reiserfs_read_lock_xattrs(inode->i_sb);
451		error = reiserfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
452		if (lock)
453			reiserfs_write_unlock_xattrs(inode->i_sb);
454		else
455			reiserfs_read_unlock_xattrs(inode->i_sb);
456		reiserfs_write_unlock_xattr_i(inode);
457	}
458	posix_acl_release(clone);
459	return error;
460}
461
462static int
463posix_acl_access_get(struct inode *inode, const char *name,
464		     void *buffer, size_t size)
465{
466	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
467		return -EINVAL;
468	return xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
469}
470
471static int
472posix_acl_access_set(struct inode *inode, const char *name,
473		     const void *value, size_t size, int flags)
474{
475	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
476		return -EINVAL;
477	return xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
478}
479
480static int posix_acl_access_del(struct inode *inode, const char *name)
481{
482	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
483	struct posix_acl **acl = &reiserfs_i->i_acl_access;
484	if (strlen(name) != sizeof(POSIX_ACL_XATTR_ACCESS) - 1)
485		return -EINVAL;
486	if (!IS_ERR(*acl) && *acl) {
487		posix_acl_release(*acl);
488		*acl = ERR_PTR(-ENODATA);
489	}
490
491	return 0;
492}
493
494static int
495posix_acl_access_list(struct inode *inode, const char *name, int namelen,
496		      char *out)
497{
498	int len = namelen;
499	if (!reiserfs_posixacl(inode->i_sb))
500		return 0;
501	if (out)
502		memcpy(out, name, len);
503
504	return len;
505}
506
507struct reiserfs_xattr_handler posix_acl_access_handler = {
508	.prefix = POSIX_ACL_XATTR_ACCESS,
509	.get = posix_acl_access_get,
510	.set = posix_acl_access_set,
511	.del = posix_acl_access_del,
512	.list = posix_acl_access_list,
513};
514
515static int
516posix_acl_default_get(struct inode *inode, const char *name,
517		      void *buffer, size_t size)
518{
519	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
520		return -EINVAL;
521	return xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
522}
523
524static int
525posix_acl_default_set(struct inode *inode, const char *name,
526		      const void *value, size_t size, int flags)
527{
528	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
529		return -EINVAL;
530	return xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
531}
532
533static int posix_acl_default_del(struct inode *inode, const char *name)
534{
535	struct reiserfs_inode_info *reiserfs_i = REISERFS_I(inode);
536	struct posix_acl **acl = &reiserfs_i->i_acl_default;
537	if (strlen(name) != sizeof(POSIX_ACL_XATTR_DEFAULT) - 1)
538		return -EINVAL;
539	if (!IS_ERR(*acl) && *acl) {
540		posix_acl_release(*acl);
541		*acl = ERR_PTR(-ENODATA);
542	}
543
544	return 0;
545}
546
547static int
548posix_acl_default_list(struct inode *inode, const char *name, int namelen,
549		       char *out)
550{
551	int len = namelen;
552	if (!reiserfs_posixacl(inode->i_sb))
553		return 0;
554	if (out)
555		memcpy(out, name, len);
556
557	return len;
558}
559
560struct reiserfs_xattr_handler posix_acl_default_handler = {
561	.prefix = POSIX_ACL_XATTR_DEFAULT,
562	.get = posix_acl_default_get,
563	.set = posix_acl_default_set,
564	.del = posix_acl_default_del,
565	.list = posix_acl_default_list,
566};
567