1/*
2 * fs/f2fs/xattr.c
3 *
4 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5 *             http://www.samsung.com/
6 *
7 * Portions of this code from linux/fs/ext2/xattr.c
8 *
9 * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
10 *
11 * Fix by Harrison Xing <harrison@mountainviewdata.com>.
12 * Extended attributes for symlinks and special files added per
13 *  suggestion of Luka Renko <luka.renko@hermes.si>.
14 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
15 *  Red Hat Inc.
16 *
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License version 2 as
19 * published by the Free Software Foundation.
20 */
21#include <linux/rwsem.h>
22#include <linux/f2fs_fs.h>
23#include <linux/security.h>
24#include <linux/posix_acl_xattr.h>
25#include "f2fs.h"
26#include "xattr.h"
27
28static size_t f2fs_xattr_generic_list(struct dentry *dentry, char *list,
29		size_t list_size, const char *name, size_t len, int type)
30{
31	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
32	int total_len, prefix_len = 0;
33	const char *prefix = NULL;
34
35	switch (type) {
36	case F2FS_XATTR_INDEX_USER:
37		if (!test_opt(sbi, XATTR_USER))
38			return -EOPNOTSUPP;
39		prefix = XATTR_USER_PREFIX;
40		prefix_len = XATTR_USER_PREFIX_LEN;
41		break;
42	case F2FS_XATTR_INDEX_TRUSTED:
43		if (!capable(CAP_SYS_ADMIN))
44			return -EPERM;
45		prefix = XATTR_TRUSTED_PREFIX;
46		prefix_len = XATTR_TRUSTED_PREFIX_LEN;
47		break;
48	case F2FS_XATTR_INDEX_SECURITY:
49		prefix = XATTR_SECURITY_PREFIX;
50		prefix_len = XATTR_SECURITY_PREFIX_LEN;
51		break;
52	default:
53		return -EINVAL;
54	}
55
56	total_len = prefix_len + len + 1;
57	if (list && total_len <= list_size) {
58		memcpy(list, prefix, prefix_len);
59		memcpy(list + prefix_len, name, len);
60		list[prefix_len + len] = '\0';
61	}
62	return total_len;
63}
64
65static int f2fs_xattr_generic_get(struct dentry *dentry, const char *name,
66		void *buffer, size_t size, int type)
67{
68	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
69
70	switch (type) {
71	case F2FS_XATTR_INDEX_USER:
72		if (!test_opt(sbi, XATTR_USER))
73			return -EOPNOTSUPP;
74		break;
75	case F2FS_XATTR_INDEX_TRUSTED:
76		if (!capable(CAP_SYS_ADMIN))
77			return -EPERM;
78		break;
79	case F2FS_XATTR_INDEX_SECURITY:
80		break;
81	default:
82		return -EINVAL;
83	}
84	if (strcmp(name, "") == 0)
85		return -EINVAL;
86	return f2fs_getxattr(d_inode(dentry), type, name, buffer, size, NULL);
87}
88
89static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
90		const void *value, size_t size, int flags, int type)
91{
92	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
93
94	switch (type) {
95	case F2FS_XATTR_INDEX_USER:
96		if (!test_opt(sbi, XATTR_USER))
97			return -EOPNOTSUPP;
98		break;
99	case F2FS_XATTR_INDEX_TRUSTED:
100		if (!capable(CAP_SYS_ADMIN))
101			return -EPERM;
102		break;
103	case F2FS_XATTR_INDEX_SECURITY:
104		break;
105	default:
106		return -EINVAL;
107	}
108	if (strcmp(name, "") == 0)
109		return -EINVAL;
110
111	return f2fs_setxattr(d_inode(dentry), type, name,
112					value, size, NULL, flags);
113}
114
115static size_t f2fs_xattr_advise_list(struct dentry *dentry, char *list,
116		size_t list_size, const char *name, size_t len, int type)
117{
118	const char *xname = F2FS_SYSTEM_ADVISE_PREFIX;
119	size_t size;
120
121	if (type != F2FS_XATTR_INDEX_ADVISE)
122		return 0;
123
124	size = strlen(xname) + 1;
125	if (list && size <= list_size)
126		memcpy(list, xname, size);
127	return size;
128}
129
130static int f2fs_xattr_advise_get(struct dentry *dentry, const char *name,
131		void *buffer, size_t size, int type)
132{
133	struct inode *inode = d_inode(dentry);
134
135	if (strcmp(name, "") != 0)
136		return -EINVAL;
137
138	if (buffer)
139		*((char *)buffer) = F2FS_I(inode)->i_advise;
140	return sizeof(char);
141}
142
143static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
144		const void *value, size_t size, int flags, int type)
145{
146	struct inode *inode = d_inode(dentry);
147
148	if (strcmp(name, "") != 0)
149		return -EINVAL;
150	if (!inode_owner_or_capable(inode))
151		return -EPERM;
152	if (value == NULL)
153		return -EINVAL;
154
155	F2FS_I(inode)->i_advise |= *(char *)value;
156	mark_inode_dirty(inode);
157	return 0;
158}
159
160#ifdef CONFIG_F2FS_FS_SECURITY
161static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
162		void *page)
163{
164	const struct xattr *xattr;
165	int err = 0;
166
167	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
168		err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
169				xattr->name, xattr->value,
170				xattr->value_len, (struct page *)page, 0);
171		if (err < 0)
172			break;
173	}
174	return err;
175}
176
177int f2fs_init_security(struct inode *inode, struct inode *dir,
178				const struct qstr *qstr, struct page *ipage)
179{
180	return security_inode_init_security(inode, dir, qstr,
181				&f2fs_initxattrs, ipage);
182}
183#endif
184
185const struct xattr_handler f2fs_xattr_user_handler = {
186	.prefix	= XATTR_USER_PREFIX,
187	.flags	= F2FS_XATTR_INDEX_USER,
188	.list	= f2fs_xattr_generic_list,
189	.get	= f2fs_xattr_generic_get,
190	.set	= f2fs_xattr_generic_set,
191};
192
193const struct xattr_handler f2fs_xattr_trusted_handler = {
194	.prefix	= XATTR_TRUSTED_PREFIX,
195	.flags	= F2FS_XATTR_INDEX_TRUSTED,
196	.list	= f2fs_xattr_generic_list,
197	.get	= f2fs_xattr_generic_get,
198	.set	= f2fs_xattr_generic_set,
199};
200
201const struct xattr_handler f2fs_xattr_advise_handler = {
202	.prefix = F2FS_SYSTEM_ADVISE_PREFIX,
203	.flags	= F2FS_XATTR_INDEX_ADVISE,
204	.list   = f2fs_xattr_advise_list,
205	.get    = f2fs_xattr_advise_get,
206	.set    = f2fs_xattr_advise_set,
207};
208
209const struct xattr_handler f2fs_xattr_security_handler = {
210	.prefix	= XATTR_SECURITY_PREFIX,
211	.flags	= F2FS_XATTR_INDEX_SECURITY,
212	.list	= f2fs_xattr_generic_list,
213	.get	= f2fs_xattr_generic_get,
214	.set	= f2fs_xattr_generic_set,
215};
216
217static const struct xattr_handler *f2fs_xattr_handler_map[] = {
218	[F2FS_XATTR_INDEX_USER] = &f2fs_xattr_user_handler,
219#ifdef CONFIG_F2FS_FS_POSIX_ACL
220	[F2FS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
221	[F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler,
222#endif
223	[F2FS_XATTR_INDEX_TRUSTED] = &f2fs_xattr_trusted_handler,
224#ifdef CONFIG_F2FS_FS_SECURITY
225	[F2FS_XATTR_INDEX_SECURITY] = &f2fs_xattr_security_handler,
226#endif
227	[F2FS_XATTR_INDEX_ADVISE] = &f2fs_xattr_advise_handler,
228};
229
230const struct xattr_handler *f2fs_xattr_handlers[] = {
231	&f2fs_xattr_user_handler,
232#ifdef CONFIG_F2FS_FS_POSIX_ACL
233	&posix_acl_access_xattr_handler,
234	&posix_acl_default_xattr_handler,
235#endif
236	&f2fs_xattr_trusted_handler,
237#ifdef CONFIG_F2FS_FS_SECURITY
238	&f2fs_xattr_security_handler,
239#endif
240	&f2fs_xattr_advise_handler,
241	NULL,
242};
243
244static inline const struct xattr_handler *f2fs_xattr_handler(int index)
245{
246	const struct xattr_handler *handler = NULL;
247
248	if (index > 0 && index < ARRAY_SIZE(f2fs_xattr_handler_map))
249		handler = f2fs_xattr_handler_map[index];
250	return handler;
251}
252
253static struct f2fs_xattr_entry *__find_xattr(void *base_addr, int index,
254					size_t len, const char *name)
255{
256	struct f2fs_xattr_entry *entry;
257
258	list_for_each_xattr(entry, base_addr) {
259		if (entry->e_name_index != index)
260			continue;
261		if (entry->e_name_len != len)
262			continue;
263		if (!memcmp(entry->e_name, name, len))
264			break;
265	}
266	return entry;
267}
268
269static void *read_all_xattrs(struct inode *inode, struct page *ipage)
270{
271	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
272	struct f2fs_xattr_header *header;
273	size_t size = PAGE_SIZE, inline_size = 0;
274	void *txattr_addr;
275
276	inline_size = inline_xattr_size(inode);
277
278	txattr_addr = kzalloc(inline_size + size, GFP_F2FS_ZERO);
279	if (!txattr_addr)
280		return NULL;
281
282	/* read from inline xattr */
283	if (inline_size) {
284		struct page *page = NULL;
285		void *inline_addr;
286
287		if (ipage) {
288			inline_addr = inline_xattr_addr(ipage);
289		} else {
290			page = get_node_page(sbi, inode->i_ino);
291			if (IS_ERR(page))
292				goto fail;
293			inline_addr = inline_xattr_addr(page);
294		}
295		memcpy(txattr_addr, inline_addr, inline_size);
296		f2fs_put_page(page, 1);
297	}
298
299	/* read from xattr node block */
300	if (F2FS_I(inode)->i_xattr_nid) {
301		struct page *xpage;
302		void *xattr_addr;
303
304		/* The inode already has an extended attribute block. */
305		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
306		if (IS_ERR(xpage))
307			goto fail;
308
309		xattr_addr = page_address(xpage);
310		memcpy(txattr_addr + inline_size, xattr_addr, PAGE_SIZE);
311		f2fs_put_page(xpage, 1);
312	}
313
314	header = XATTR_HDR(txattr_addr);
315
316	/* never been allocated xattrs */
317	if (le32_to_cpu(header->h_magic) != F2FS_XATTR_MAGIC) {
318		header->h_magic = cpu_to_le32(F2FS_XATTR_MAGIC);
319		header->h_refcount = cpu_to_le32(1);
320	}
321	return txattr_addr;
322fail:
323	kzfree(txattr_addr);
324	return NULL;
325}
326
327static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
328				void *txattr_addr, struct page *ipage)
329{
330	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
331	size_t inline_size = 0;
332	void *xattr_addr;
333	struct page *xpage;
334	nid_t new_nid = 0;
335	int err;
336
337	inline_size = inline_xattr_size(inode);
338
339	if (hsize > inline_size && !F2FS_I(inode)->i_xattr_nid)
340		if (!alloc_nid(sbi, &new_nid))
341			return -ENOSPC;
342
343	/* write to inline xattr */
344	if (inline_size) {
345		struct page *page = NULL;
346		void *inline_addr;
347
348		if (ipage) {
349			inline_addr = inline_xattr_addr(ipage);
350			f2fs_wait_on_page_writeback(ipage, NODE);
351		} else {
352			page = get_node_page(sbi, inode->i_ino);
353			if (IS_ERR(page)) {
354				alloc_nid_failed(sbi, new_nid);
355				return PTR_ERR(page);
356			}
357			inline_addr = inline_xattr_addr(page);
358			f2fs_wait_on_page_writeback(page, NODE);
359		}
360		memcpy(inline_addr, txattr_addr, inline_size);
361		f2fs_put_page(page, 1);
362
363		/* no need to use xattr node block */
364		if (hsize <= inline_size) {
365			err = truncate_xattr_node(inode, ipage);
366			alloc_nid_failed(sbi, new_nid);
367			return err;
368		}
369	}
370
371	/* write to xattr node block */
372	if (F2FS_I(inode)->i_xattr_nid) {
373		xpage = get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
374		if (IS_ERR(xpage)) {
375			alloc_nid_failed(sbi, new_nid);
376			return PTR_ERR(xpage);
377		}
378		f2fs_bug_on(sbi, new_nid);
379		f2fs_wait_on_page_writeback(xpage, NODE);
380	} else {
381		struct dnode_of_data dn;
382		set_new_dnode(&dn, inode, NULL, NULL, new_nid);
383		xpage = new_node_page(&dn, XATTR_NODE_OFFSET, ipage);
384		if (IS_ERR(xpage)) {
385			alloc_nid_failed(sbi, new_nid);
386			return PTR_ERR(xpage);
387		}
388		alloc_nid_done(sbi, new_nid);
389	}
390
391	xattr_addr = page_address(xpage);
392	memcpy(xattr_addr, txattr_addr + inline_size, PAGE_SIZE -
393						sizeof(struct node_footer));
394	set_page_dirty(xpage);
395	f2fs_put_page(xpage, 1);
396
397	/* need to checkpoint during fsync */
398	F2FS_I(inode)->xattr_ver = cur_cp_version(F2FS_CKPT(sbi));
399	return 0;
400}
401
402int f2fs_getxattr(struct inode *inode, int index, const char *name,
403		void *buffer, size_t buffer_size, struct page *ipage)
404{
405	struct f2fs_xattr_entry *entry;
406	void *base_addr;
407	int error = 0;
408	size_t size, len;
409
410	if (name == NULL)
411		return -EINVAL;
412
413	len = strlen(name);
414	if (len > F2FS_NAME_LEN)
415		return -ERANGE;
416
417	base_addr = read_all_xattrs(inode, ipage);
418	if (!base_addr)
419		return -ENOMEM;
420
421	entry = __find_xattr(base_addr, index, len, name);
422	if (IS_XATTR_LAST_ENTRY(entry)) {
423		error = -ENODATA;
424		goto cleanup;
425	}
426
427	size = le16_to_cpu(entry->e_value_size);
428
429	if (buffer && size > buffer_size) {
430		error = -ERANGE;
431		goto cleanup;
432	}
433
434	if (buffer) {
435		char *pval = entry->e_name + entry->e_name_len;
436		memcpy(buffer, pval, size);
437	}
438	error = size;
439
440cleanup:
441	kzfree(base_addr);
442	return error;
443}
444
445ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
446{
447	struct inode *inode = d_inode(dentry);
448	struct f2fs_xattr_entry *entry;
449	void *base_addr;
450	int error = 0;
451	size_t rest = buffer_size;
452
453	base_addr = read_all_xattrs(inode, NULL);
454	if (!base_addr)
455		return -ENOMEM;
456
457	list_for_each_xattr(entry, base_addr) {
458		const struct xattr_handler *handler =
459			f2fs_xattr_handler(entry->e_name_index);
460		size_t size;
461
462		if (!handler)
463			continue;
464
465		size = handler->list(dentry, buffer, rest, entry->e_name,
466				entry->e_name_len, handler->flags);
467		if (buffer && size > rest) {
468			error = -ERANGE;
469			goto cleanup;
470		}
471
472		if (buffer)
473			buffer += size;
474		rest -= size;
475	}
476	error = buffer_size - rest;
477cleanup:
478	kzfree(base_addr);
479	return error;
480}
481
482static int __f2fs_setxattr(struct inode *inode, int index,
483			const char *name, const void *value, size_t size,
484			struct page *ipage, int flags)
485{
486	struct f2fs_inode_info *fi = F2FS_I(inode);
487	struct f2fs_xattr_entry *here, *last;
488	void *base_addr;
489	int found, newsize;
490	size_t len;
491	__u32 new_hsize;
492	int error = -ENOMEM;
493
494	if (name == NULL)
495		return -EINVAL;
496
497	if (value == NULL)
498		size = 0;
499
500	len = strlen(name);
501
502	if (len > F2FS_NAME_LEN || size > MAX_VALUE_LEN(inode))
503		return -ERANGE;
504
505	base_addr = read_all_xattrs(inode, ipage);
506	if (!base_addr)
507		goto exit;
508
509	/* find entry with wanted name. */
510	here = __find_xattr(base_addr, index, len, name);
511
512	found = IS_XATTR_LAST_ENTRY(here) ? 0 : 1;
513
514	if ((flags & XATTR_REPLACE) && !found) {
515		error = -ENODATA;
516		goto exit;
517	} else if ((flags & XATTR_CREATE) && found) {
518		error = -EEXIST;
519		goto exit;
520	}
521
522	last = here;
523	while (!IS_XATTR_LAST_ENTRY(last))
524		last = XATTR_NEXT_ENTRY(last);
525
526	newsize = XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + len + size);
527
528	/* 1. Check space */
529	if (value) {
530		int free;
531		/*
532		 * If value is NULL, it is remove operation.
533		 * In case of update operation, we calculate free.
534		 */
535		free = MIN_OFFSET(inode) - ((char *)last - (char *)base_addr);
536		if (found)
537			free = free + ENTRY_SIZE(here);
538
539		if (unlikely(free < newsize)) {
540			error = -ENOSPC;
541			goto exit;
542		}
543	}
544
545	/* 2. Remove old entry */
546	if (found) {
547		/*
548		 * If entry is found, remove old entry.
549		 * If not found, remove operation is not needed.
550		 */
551		struct f2fs_xattr_entry *next = XATTR_NEXT_ENTRY(here);
552		int oldsize = ENTRY_SIZE(here);
553
554		memmove(here, next, (char *)last - (char *)next);
555		last = (struct f2fs_xattr_entry *)((char *)last - oldsize);
556		memset(last, 0, oldsize);
557	}
558
559	new_hsize = (char *)last - (char *)base_addr;
560
561	/* 3. Write new entry */
562	if (value) {
563		char *pval;
564		/*
565		 * Before we come here, old entry is removed.
566		 * We just write new entry.
567		 */
568		memset(last, 0, newsize);
569		last->e_name_index = index;
570		last->e_name_len = len;
571		memcpy(last->e_name, name, len);
572		pval = last->e_name + len;
573		memcpy(pval, value, size);
574		last->e_value_size = cpu_to_le16(size);
575		new_hsize += newsize;
576	}
577
578	error = write_all_xattrs(inode, new_hsize, base_addr, ipage);
579	if (error)
580		goto exit;
581
582	if (is_inode_flag_set(fi, FI_ACL_MODE)) {
583		inode->i_mode = fi->i_acl_mode;
584		inode->i_ctime = CURRENT_TIME;
585		clear_inode_flag(fi, FI_ACL_MODE);
586	}
587
588	if (ipage)
589		update_inode(inode, ipage);
590	else
591		update_inode_page(inode);
592exit:
593	kzfree(base_addr);
594	return error;
595}
596
597int f2fs_setxattr(struct inode *inode, int index, const char *name,
598				const void *value, size_t size,
599				struct page *ipage, int flags)
600{
601	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
602	int err;
603
604	/* this case is only from init_inode_metadata */
605	if (ipage)
606		return __f2fs_setxattr(inode, index, name, value,
607						size, ipage, flags);
608	f2fs_balance_fs(sbi);
609
610	f2fs_lock_op(sbi);
611	/* protect xattr_ver */
612	down_write(&F2FS_I(inode)->i_sem);
613	err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);
614	up_write(&F2FS_I(inode)->i_sem);
615	f2fs_unlock_op(sbi);
616
617	return err;
618}
619