1/*
  2 * fs/f2fs/acl.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/acl.c
  8 *
  9 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 10 *
 11 * This program is free software; you can redistribute it and/or modify
 12 * it under the terms of the GNU General Public License version 2 as
 13 * published by the Free Software Foundation.
 14 */
 15#include <linux/f2fs_fs.h>
 16#include "f2fs.h"
 17#include "xattr.h"
 18#include "acl.h"
 19
 20static inline size_t f2fs_acl_size(int count)
 21{
 22	if (count <= 4) {
 23		return sizeof(struct f2fs_acl_header) +
 24			count * sizeof(struct f2fs_acl_entry_short);
 25	} else {
 26		return sizeof(struct f2fs_acl_header) +
 27			4 * sizeof(struct f2fs_acl_entry_short) +
 28			(count - 4) * sizeof(struct f2fs_acl_entry);
 29	}
 30}
 31
 32static inline int f2fs_acl_count(size_t size)
 33{
 34	ssize_t s;
 35	size -= sizeof(struct f2fs_acl_header);
 36	s = size - 4 * sizeof(struct f2fs_acl_entry_short);
 37	if (s < 0) {
 38		if (size % sizeof(struct f2fs_acl_entry_short))
 39			return -1;
 40		return size / sizeof(struct f2fs_acl_entry_short);
 41	} else {
 42		if (s % sizeof(struct f2fs_acl_entry))
 43			return -1;
 44		return s / sizeof(struct f2fs_acl_entry) + 4;
 45	}
 46}
 47
 48static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
 49{
 50	int i, count;
 51	struct posix_acl *acl;
 52	struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
 53	struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
 54	const char *end = value + size;
 55
 56	if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
 57		return ERR_PTR(-EINVAL);
 58
 59	count = f2fs_acl_count(size);
 60	if (count < 0)
 61		return ERR_PTR(-EINVAL);
 62	if (count == 0)
 63		return NULL;
 64
 65	acl = posix_acl_alloc(count, GFP_KERNEL);
 66	if (!acl)
 67		return ERR_PTR(-ENOMEM);
 68
 69	for (i = 0; i < count; i++) {
 70
 71		if ((char *)entry > end)
 72			goto fail;
 73
 74		acl->a_entries[i].e_tag  = le16_to_cpu(entry->e_tag);
 75		acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
 76
 77		switch (acl->a_entries[i].e_tag) {
 78		case ACL_USER_OBJ:
 79		case ACL_GROUP_OBJ:
 80		case ACL_MASK:
 81		case ACL_OTHER:
 82			entry = (struct f2fs_acl_entry *)((char *)entry +
 83					sizeof(struct f2fs_acl_entry_short));
 84			break;
 85
 86		case ACL_USER:
 87			acl->a_entries[i].e_uid =
 88				make_kuid(&init_user_ns,
 89						le32_to_cpu(entry->e_id));
 90			entry = (struct f2fs_acl_entry *)((char *)entry +
 91					sizeof(struct f2fs_acl_entry));
 92			break;
 93		case ACL_GROUP:
 94			acl->a_entries[i].e_gid =
 95				make_kgid(&init_user_ns,
 96						le32_to_cpu(entry->e_id));
 97			entry = (struct f2fs_acl_entry *)((char *)entry +
 98					sizeof(struct f2fs_acl_entry));
 99			break;
100		default:
101			goto fail;
102		}
103	}
104	if ((char *)entry != end)
105		goto fail;
106	return acl;
107fail:
108	posix_acl_release(acl);
109	return ERR_PTR(-EINVAL);
110}
111
112static void *f2fs_acl_to_disk(const struct posix_acl *acl, size_t *size)
113{
114	struct f2fs_acl_header *f2fs_acl;
115	struct f2fs_acl_entry *entry;
116	int i;
117
118	f2fs_acl = kmalloc(sizeof(struct f2fs_acl_header) + acl->a_count *
119			sizeof(struct f2fs_acl_entry), GFP_KERNEL);
120	if (!f2fs_acl)
121		return ERR_PTR(-ENOMEM);
122
123	f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
124	entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
125
126	for (i = 0; i < acl->a_count; i++) {
127
128		entry->e_tag  = cpu_to_le16(acl->a_entries[i].e_tag);
129		entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
130
131		switch (acl->a_entries[i].e_tag) {
132		case ACL_USER:
133			entry->e_id = cpu_to_le32(
134					from_kuid(&init_user_ns,
135						acl->a_entries[i].e_uid));
136			entry = (struct f2fs_acl_entry *)((char *)entry +
137					sizeof(struct f2fs_acl_entry));
138			break;
139		case ACL_GROUP:
140			entry->e_id = cpu_to_le32(
141					from_kgid(&init_user_ns,
142						acl->a_entries[i].e_gid));
143			entry = (struct f2fs_acl_entry *)((char *)entry +
144					sizeof(struct f2fs_acl_entry));
145			break;
146		case ACL_USER_OBJ:
147		case ACL_GROUP_OBJ:
148		case ACL_MASK:
149		case ACL_OTHER:
150			entry = (struct f2fs_acl_entry *)((char *)entry +
151					sizeof(struct f2fs_acl_entry_short));
152			break;
153		default:
154			goto fail;
155		}
156	}
157	*size = f2fs_acl_size(acl->a_count);
158	return (void *)f2fs_acl;
159
160fail:
161	kfree(f2fs_acl);
162	return ERR_PTR(-EINVAL);
163}
164
165struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
166{
167	int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
168	void *value = NULL;
169	struct posix_acl *acl;
170	int retval;
171
172	if (type == ACL_TYPE_ACCESS)
173		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
174
175	retval = f2fs_getxattr(inode, name_index, "", NULL, 0);
176	if (retval > 0) {
177		value = kmalloc(retval, GFP_F2FS_ZERO);
178		if (!value)
179			return ERR_PTR(-ENOMEM);
180		retval = f2fs_getxattr(inode, name_index, "", value, retval);
181	}
182
183	if (retval > 0)
184		acl = f2fs_acl_from_disk(value, retval);
185	else if (retval == -ENODATA)
186		acl = NULL;
187	else
188		acl = ERR_PTR(retval);
189	kfree(value);
190
191	if (!IS_ERR(acl))
192		set_cached_acl(inode, type, acl);
193
194	return acl;
195}
196
197static int __f2fs_set_acl(struct inode *inode, int type,
198			struct posix_acl *acl, struct page *ipage)
199{
200	struct f2fs_inode_info *fi = F2FS_I(inode);
201	int name_index;
202	void *value = NULL;
203	size_t size = 0;
204	int error;
205
206	if (acl) {
207		error = posix_acl_valid(acl);
208		if (error < 0)
209			return error;
210	}
211
212	switch (type) {
213	case ACL_TYPE_ACCESS:
214		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
215		if (acl) {
216			error = posix_acl_equiv_mode(acl, &inode->i_mode);
217			if (error < 0)
218				return error;
219			set_acl_inode(fi, inode->i_mode);
220			if (error == 0)
221				acl = NULL;
222		}
223		break;
224
225	case ACL_TYPE_DEFAULT:
226		name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
227		if (!S_ISDIR(inode->i_mode))
228			return acl ? -EACCES : 0;
229		break;
230
231	default:
232		return -EINVAL;
233	}
234
235	if (acl) {
236		value = f2fs_acl_to_disk(acl, &size);
237		if (IS_ERR(value)) {
238			cond_clear_inode_flag(fi, FI_ACL_MODE);
239			return (int)PTR_ERR(value);
240		}
241	}
242
243	error = f2fs_setxattr(inode, name_index, "", value, size, ipage);
244
245	kfree(value);
246	if (!error)
247		set_cached_acl(inode, type, acl);
248
249	cond_clear_inode_flag(fi, FI_ACL_MODE);
250	return error;
251}
252
253int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
254{
255	return __f2fs_set_acl(inode, type, acl, NULL);
256}
257
258int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage)
259{
260	struct posix_acl *default_acl, *acl;
261	int error = 0;
262
263	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
264	if (error)
265		return error;
266
267	if (default_acl) {
268		error = __f2fs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl,
269				       ipage);
270		posix_acl_release(default_acl);
271	}
272	if (acl) {
273		if (error)
274			error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl,
275					       ipage);
276		posix_acl_release(acl);
277	}
278
279	return error;
280}