1 #include <linux/capability.h>
2 #include <linux/fs.h>
3 #include <linux/posix_acl.h>
4 #include "reiserfs.h"
5 #include <linux/errno.h>
6 #include <linux/pagemap.h>
7 #include <linux/xattr.h>
8 #include <linux/slab.h>
9 #include <linux/posix_acl_xattr.h>
10 #include "xattr.h"
11 #include "acl.h"
12 #include <asm/uaccess.h>
13 
14 static int reiserfs_set_acl(struct reiserfs_transaction_handle *th,
15 			    struct inode *inode, int type,
16 			    struct posix_acl *acl);
17 
18 static int
posix_acl_set(struct dentry * dentry,const char * name,const void * value,size_t size,int flags,int type)19 posix_acl_set(struct dentry *dentry, const char *name, const void *value,
20 		size_t size, int flags, int type)
21 {
22 	struct inode *inode = dentry->d_inode;
23 	struct posix_acl *acl;
24 	int error, error2;
25 	struct reiserfs_transaction_handle th;
26 	size_t jcreate_blocks;
27 	if (!reiserfs_posixacl(inode->i_sb))
28 		return -EOPNOTSUPP;
29 	if (!inode_owner_or_capable(inode))
30 		return -EPERM;
31 
32 	if (value) {
33 		acl = posix_acl_from_xattr(value, size);
34 		if (IS_ERR(acl)) {
35 			return PTR_ERR(acl);
36 		} else if (acl) {
37 			error = posix_acl_valid(acl);
38 			if (error)
39 				goto release_and_out;
40 		}
41 	} else
42 		acl = NULL;
43 
44 	/* Pessimism: We can't assume that anything from the xattr root up
45 	 * has been created. */
46 
47 	jcreate_blocks = reiserfs_xattr_jcreate_nblocks(inode) +
48 			 reiserfs_xattr_nblocks(inode, size) * 2;
49 
50 	reiserfs_write_lock(inode->i_sb);
51 	error = journal_begin(&th, inode->i_sb, jcreate_blocks);
52 	if (error == 0) {
53 		error = reiserfs_set_acl(&th, inode, type, acl);
54 		error2 = journal_end(&th, inode->i_sb, jcreate_blocks);
55 		if (error2)
56 			error = error2;
57 	}
58 	reiserfs_write_unlock(inode->i_sb);
59 
60       release_and_out:
61 	posix_acl_release(acl);
62 	return error;
63 }
64 
65 static int
posix_acl_get(struct dentry * dentry,const char * name,void * buffer,size_t size,int type)66 posix_acl_get(struct dentry *dentry, const char *name, void *buffer,
67 		size_t size, int type)
68 {
69 	struct posix_acl *acl;
70 	int error;
71 
72 	if (!reiserfs_posixacl(dentry->d_sb))
73 		return -EOPNOTSUPP;
74 
75 	acl = reiserfs_get_acl(dentry->d_inode, type);
76 	if (IS_ERR(acl))
77 		return PTR_ERR(acl);
78 	if (acl == NULL)
79 		return -ENODATA;
80 	error = posix_acl_to_xattr(acl, buffer, size);
81 	posix_acl_release(acl);
82 
83 	return error;
84 }
85 
86 /*
87  * Convert from filesystem to in-memory representation.
88  */
posix_acl_from_disk(const void * value,size_t size)89 static struct posix_acl *posix_acl_from_disk(const void *value, size_t size)
90 {
91 	const char *end = (char *)value + size;
92 	int n, count;
93 	struct posix_acl *acl;
94 
95 	if (!value)
96 		return NULL;
97 	if (size < sizeof(reiserfs_acl_header))
98 		return ERR_PTR(-EINVAL);
99 	if (((reiserfs_acl_header *) value)->a_version !=
100 	    cpu_to_le32(REISERFS_ACL_VERSION))
101 		return ERR_PTR(-EINVAL);
102 	value = (char *)value + sizeof(reiserfs_acl_header);
103 	count = reiserfs_acl_count(size);
104 	if (count < 0)
105 		return ERR_PTR(-EINVAL);
106 	if (count == 0)
107 		return NULL;
108 	acl = posix_acl_alloc(count, GFP_NOFS);
109 	if (!acl)
110 		return ERR_PTR(-ENOMEM);
111 	for (n = 0; n < count; n++) {
112 		reiserfs_acl_entry *entry = (reiserfs_acl_entry *) value;
113 		if ((char *)value + sizeof(reiserfs_acl_entry_short) > end)
114 			goto fail;
115 		acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
116 		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
117 		switch (acl->a_entries[n].e_tag) {
118 		case ACL_USER_OBJ:
119 		case ACL_GROUP_OBJ:
120 		case ACL_MASK:
121 		case ACL_OTHER:
122 			value = (char *)value +
123 			    sizeof(reiserfs_acl_entry_short);
124 			acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
125 			break;
126 
127 		case ACL_USER:
128 		case ACL_GROUP:
129 			value = (char *)value + sizeof(reiserfs_acl_entry);
130 			if ((char *)value > end)
131 				goto fail;
132 			acl->a_entries[n].e_id = le32_to_cpu(entry->e_id);
133 			break;
134 
135 		default:
136 			goto fail;
137 		}
138 	}
139 	if (value != end)
140 		goto fail;
141 	return acl;
142 
143       fail:
144 	posix_acl_release(acl);
145 	return ERR_PTR(-EINVAL);
146 }
147 
148 /*
149  * Convert from in-memory to filesystem representation.
150  */
posix_acl_to_disk(const struct posix_acl * acl,size_t * size)151 static void *posix_acl_to_disk(const struct posix_acl *acl, size_t * size)
152 {
153 	reiserfs_acl_header *ext_acl;
154 	char *e;
155 	int n;
156 
157 	*size = reiserfs_acl_size(acl->a_count);
158 	ext_acl = kmalloc(sizeof(reiserfs_acl_header) +
159 						  acl->a_count *
160 						  sizeof(reiserfs_acl_entry),
161 						  GFP_NOFS);
162 	if (!ext_acl)
163 		return ERR_PTR(-ENOMEM);
164 	ext_acl->a_version = cpu_to_le32(REISERFS_ACL_VERSION);
165 	e = (char *)ext_acl + sizeof(reiserfs_acl_header);
166 	for (n = 0; n < acl->a_count; n++) {
167 		reiserfs_acl_entry *entry = (reiserfs_acl_entry *) e;
168 		entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
169 		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
170 		switch (acl->a_entries[n].e_tag) {
171 		case ACL_USER:
172 		case ACL_GROUP:
173 			entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
174 			e += sizeof(reiserfs_acl_entry);
175 			break;
176 
177 		case ACL_USER_OBJ:
178 		case ACL_GROUP_OBJ:
179 		case ACL_MASK:
180 		case ACL_OTHER:
181 			e += sizeof(reiserfs_acl_entry_short);
182 			break;
183 
184 		default:
185 			goto fail;
186 		}
187 	}
188 	return (char *)ext_acl;
189 
190       fail:
191 	kfree(ext_acl);
192 	return ERR_PTR(-EINVAL);
193 }
194 
195 /*
196  * Inode operation get_posix_acl().
197  *
198  * inode->i_mutex: down
199  * BKL held [before 2.5.x]
200  */
reiserfs_get_acl(struct inode * inode,int type)201 struct posix_acl *reiserfs_get_acl(struct inode *inode, int type)
202 {
203 	char *name, *value;
204 	struct posix_acl *acl;
205 	int size;
206 	int retval;
207 
208 	acl = get_cached_acl(inode, type);
209 	if (acl != ACL_NOT_CACHED)
210 		return acl;
211 
212 	switch (type) {
213 	case ACL_TYPE_ACCESS:
214 		name = POSIX_ACL_XATTR_ACCESS;
215 		break;
216 	case ACL_TYPE_DEFAULT:
217 		name = POSIX_ACL_XATTR_DEFAULT;
218 		break;
219 	default:
220 		BUG();
221 	}
222 
223 	size = reiserfs_xattr_get(inode, name, NULL, 0);
224 	if (size < 0) {
225 		if (size == -ENODATA || size == -ENOSYS) {
226 			set_cached_acl(inode, type, NULL);
227 			return NULL;
228 		}
229 		return ERR_PTR(size);
230 	}
231 
232 	value = kmalloc(size, GFP_NOFS);
233 	if (!value)
234 		return ERR_PTR(-ENOMEM);
235 
236 	retval = reiserfs_xattr_get(inode, name, value, size);
237 	if (retval == -ENODATA || retval == -ENOSYS) {
238 		/* This shouldn't actually happen as it should have
239 		   been caught above.. but just in case */
240 		acl = NULL;
241 	} else if (retval < 0) {
242 		acl = ERR_PTR(retval);
243 	} else {
244 		acl = posix_acl_from_disk(value, retval);
245 	}
246 	if (!IS_ERR(acl))
247 		set_cached_acl(inode, type, acl);
248 
249 	kfree(value);
250 	return acl;
251 }
252 
253 /*
254  * Inode operation set_posix_acl().
255  *
256  * inode->i_mutex: down
257  * BKL held [before 2.5.x]
258  */
259 static int
reiserfs_set_acl(struct reiserfs_transaction_handle * th,struct inode * inode,int type,struct posix_acl * acl)260 reiserfs_set_acl(struct reiserfs_transaction_handle *th, struct inode *inode,
261 		 int type, struct posix_acl *acl)
262 {
263 	char *name;
264 	void *value = NULL;
265 	size_t size = 0;
266 	int error;
267 
268 	if (S_ISLNK(inode->i_mode))
269 		return -EOPNOTSUPP;
270 
271 	switch (type) {
272 	case ACL_TYPE_ACCESS:
273 		name = POSIX_ACL_XATTR_ACCESS;
274 		if (acl) {
275 			error = posix_acl_equiv_mode(acl, &inode->i_mode);
276 			if (error < 0)
277 				return error;
278 			else {
279 				if (error == 0)
280 					acl = NULL;
281 			}
282 		}
283 		break;
284 	case ACL_TYPE_DEFAULT:
285 		name = POSIX_ACL_XATTR_DEFAULT;
286 		if (!S_ISDIR(inode->i_mode))
287 			return acl ? -EACCES : 0;
288 		break;
289 	default:
290 		return -EINVAL;
291 	}
292 
293 	if (acl) {
294 		value = posix_acl_to_disk(acl, &size);
295 		if (IS_ERR(value))
296 			return (int)PTR_ERR(value);
297 	}
298 
299 	error = reiserfs_xattr_set_handle(th, inode, name, value, size, 0);
300 
301 	/*
302 	 * Ensure that the inode gets dirtied if we're only using
303 	 * the mode bits and an old ACL didn't exist. We don't need
304 	 * to check if the inode is hashed here since we won't get
305 	 * called by reiserfs_inherit_default_acl().
306 	 */
307 	if (error == -ENODATA) {
308 		error = 0;
309 		if (type == ACL_TYPE_ACCESS) {
310 			inode->i_ctime = CURRENT_TIME_SEC;
311 			mark_inode_dirty(inode);
312 		}
313 	}
314 
315 	kfree(value);
316 
317 	if (!error)
318 		set_cached_acl(inode, type, acl);
319 
320 	return error;
321 }
322 
323 /* dir->i_mutex: locked,
324  * inode is new and not released into the wild yet */
325 int
reiserfs_inherit_default_acl(struct reiserfs_transaction_handle * th,struct inode * dir,struct dentry * dentry,struct inode * inode)326 reiserfs_inherit_default_acl(struct reiserfs_transaction_handle *th,
327 			     struct inode *dir, struct dentry *dentry,
328 			     struct inode *inode)
329 {
330 	struct posix_acl *acl;
331 	int err = 0;
332 
333 	/* ACLs only get applied to files and directories */
334 	if (S_ISLNK(inode->i_mode))
335 		return 0;
336 
337 	/* ACLs can only be used on "new" objects, so if it's an old object
338 	 * there is nothing to inherit from */
339 	if (get_inode_sd_version(dir) == STAT_DATA_V1)
340 		goto apply_umask;
341 
342 	/* Don't apply ACLs to objects in the .reiserfs_priv tree.. This
343 	 * would be useless since permissions are ignored, and a pain because
344 	 * it introduces locking cycles */
345 	if (IS_PRIVATE(dir)) {
346 		inode->i_flags |= S_PRIVATE;
347 		goto apply_umask;
348 	}
349 
350 	acl = reiserfs_get_acl(dir, ACL_TYPE_DEFAULT);
351 	if (IS_ERR(acl))
352 		return PTR_ERR(acl);
353 
354 	if (acl) {
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(th, inode, ACL_TYPE_DEFAULT,
358 					       acl);
359 			if (err)
360 				goto cleanup;
361 		}
362 
363 		/* Now we reconcile the new ACL and the mode,
364 		   potentially modifying both */
365 		err = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
366 		if (err < 0)
367 			return err;
368 
369 		/* If we need an ACL.. */
370 		if (err > 0)
371 			err = reiserfs_set_acl(th, inode, ACL_TYPE_ACCESS, acl);
372 	      cleanup:
373 		posix_acl_release(acl);
374 	} else {
375 	      apply_umask:
376 		/* no ACL, apply umask */
377 		inode->i_mode &= ~current_umask();
378 	}
379 
380 	return err;
381 }
382 
383 /* This is used to cache the default acl before a new object is created.
384  * The biggest reason for this is to get an idea of how many blocks will
385  * actually be required for the create operation if we must inherit an ACL.
386  * An ACL write can add up to 3 object creations and an additional file write
387  * so we'd prefer not to reserve that many blocks in the journal if we can.
388  * It also has the advantage of not loading the ACL with a transaction open,
389  * this may seem silly, but if the owner of the directory is doing the
390  * creation, the ACL may not be loaded since the permissions wouldn't require
391  * it.
392  * We return the number of blocks required for the transaction.
393  */
reiserfs_cache_default_acl(struct inode * inode)394 int reiserfs_cache_default_acl(struct inode *inode)
395 {
396 	struct posix_acl *acl;
397 	int nblocks = 0;
398 
399 	if (IS_PRIVATE(inode))
400 		return 0;
401 
402 	acl = reiserfs_get_acl(inode, ACL_TYPE_DEFAULT);
403 
404 	if (acl && !IS_ERR(acl)) {
405 		int size = reiserfs_acl_size(acl->a_count);
406 
407 		/* Other xattrs can be created during inode creation. We don't
408 		 * want to claim too many blocks, so we check to see if we
409 		 * we need to create the tree to the xattrs, and then we
410 		 * just want two files. */
411 		nblocks = reiserfs_xattr_jcreate_nblocks(inode);
412 		nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
413 
414 		REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
415 
416 		/* We need to account for writes + bitmaps for two files */
417 		nblocks += reiserfs_xattr_nblocks(inode, size) * 4;
418 		posix_acl_release(acl);
419 	}
420 
421 	return nblocks;
422 }
423 
reiserfs_acl_chmod(struct inode * inode)424 int reiserfs_acl_chmod(struct inode *inode)
425 {
426 	struct reiserfs_transaction_handle th;
427 	struct posix_acl *acl;
428 	size_t size;
429 	int depth;
430 	int error;
431 
432 	if (S_ISLNK(inode->i_mode))
433 		return -EOPNOTSUPP;
434 
435 	if (get_inode_sd_version(inode) == STAT_DATA_V1 ||
436 	    !reiserfs_posixacl(inode->i_sb)) {
437 		return 0;
438 	}
439 
440 	reiserfs_write_unlock(inode->i_sb);
441 	acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS);
442 	reiserfs_write_lock(inode->i_sb);
443 	if (!acl)
444 		return 0;
445 	if (IS_ERR(acl))
446 		return PTR_ERR(acl);
447 	error = posix_acl_chmod(&acl, GFP_NOFS, inode->i_mode);
448 	if (error)
449 		return error;
450 
451 	size = reiserfs_xattr_nblocks(inode, reiserfs_acl_size(acl->a_count));
452 	depth = reiserfs_write_lock_once(inode->i_sb);
453 	error = journal_begin(&th, inode->i_sb, size * 2);
454 	if (!error) {
455 		int error2;
456 		error = reiserfs_set_acl(&th, inode, ACL_TYPE_ACCESS, acl);
457 		error2 = journal_end(&th, inode->i_sb, size * 2);
458 		if (error2)
459 			error = error2;
460 	}
461 	reiserfs_write_unlock_once(inode->i_sb, depth);
462 	posix_acl_release(acl);
463 	return error;
464 }
465 
posix_acl_access_list(struct dentry * dentry,char * list,size_t list_size,const char * name,size_t name_len,int type)466 static size_t posix_acl_access_list(struct dentry *dentry, char *list,
467 				    size_t list_size, const char *name,
468 				    size_t name_len, int type)
469 {
470 	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
471 	if (!reiserfs_posixacl(dentry->d_sb))
472 		return 0;
473 	if (list && size <= list_size)
474 		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
475 	return size;
476 }
477 
478 const struct xattr_handler reiserfs_posix_acl_access_handler = {
479 	.prefix = POSIX_ACL_XATTR_ACCESS,
480 	.flags = ACL_TYPE_ACCESS,
481 	.get = posix_acl_get,
482 	.set = posix_acl_set,
483 	.list = posix_acl_access_list,
484 };
485 
posix_acl_default_list(struct dentry * dentry,char * list,size_t list_size,const char * name,size_t name_len,int type)486 static size_t posix_acl_default_list(struct dentry *dentry, char *list,
487 				     size_t list_size, const char *name,
488 				     size_t name_len, int type)
489 {
490 	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
491 	if (!reiserfs_posixacl(dentry->d_sb))
492 		return 0;
493 	if (list && size <= list_size)
494 		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
495 	return size;
496 }
497 
498 const struct xattr_handler reiserfs_posix_acl_default_handler = {
499 	.prefix = POSIX_ACL_XATTR_DEFAULT,
500 	.flags = ACL_TYPE_DEFAULT,
501 	.get = posix_acl_get,
502 	.set = posix_acl_set,
503 	.list = posix_acl_default_list,
504 };
505