xref: /openbmc/linux/fs/f2fs/acl.c (revision fa7f32422ea1ac276b45b96a540ed5981caaa61f)
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  
20  static 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  
32  static 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  
48  static 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_NOFS);
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;
107  fail:
108  	posix_acl_release(acl);
109  	return ERR_PTR(-EINVAL);
110  }
111  
112  static void *f2fs_acl_to_disk(struct f2fs_sb_info *sbi,
113  				const struct posix_acl *acl, size_t *size)
114  {
115  	struct f2fs_acl_header *f2fs_acl;
116  	struct f2fs_acl_entry *entry;
117  	int i;
118  
119  	f2fs_acl = f2fs_kmalloc(sbi, sizeof(struct f2fs_acl_header) +
120  			acl->a_count * sizeof(struct f2fs_acl_entry),
121  			GFP_NOFS);
122  	if (!f2fs_acl)
123  		return ERR_PTR(-ENOMEM);
124  
125  	f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
126  	entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
127  
128  	for (i = 0; i < acl->a_count; i++) {
129  
130  		entry->e_tag  = cpu_to_le16(acl->a_entries[i].e_tag);
131  		entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
132  
133  		switch (acl->a_entries[i].e_tag) {
134  		case ACL_USER:
135  			entry->e_id = cpu_to_le32(
136  					from_kuid(&init_user_ns,
137  						acl->a_entries[i].e_uid));
138  			entry = (struct f2fs_acl_entry *)((char *)entry +
139  					sizeof(struct f2fs_acl_entry));
140  			break;
141  		case ACL_GROUP:
142  			entry->e_id = cpu_to_le32(
143  					from_kgid(&init_user_ns,
144  						acl->a_entries[i].e_gid));
145  			entry = (struct f2fs_acl_entry *)((char *)entry +
146  					sizeof(struct f2fs_acl_entry));
147  			break;
148  		case ACL_USER_OBJ:
149  		case ACL_GROUP_OBJ:
150  		case ACL_MASK:
151  		case ACL_OTHER:
152  			entry = (struct f2fs_acl_entry *)((char *)entry +
153  					sizeof(struct f2fs_acl_entry_short));
154  			break;
155  		default:
156  			goto fail;
157  		}
158  	}
159  	*size = f2fs_acl_size(acl->a_count);
160  	return (void *)f2fs_acl;
161  
162  fail:
163  	kfree(f2fs_acl);
164  	return ERR_PTR(-EINVAL);
165  }
166  
167  static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
168  						struct page *dpage)
169  {
170  	int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
171  	void *value = NULL;
172  	struct posix_acl *acl;
173  	int retval;
174  
175  	if (type == ACL_TYPE_ACCESS)
176  		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
177  
178  	retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);
179  	if (retval > 0) {
180  		value = f2fs_kmalloc(F2FS_I_SB(inode), retval, GFP_F2FS_ZERO);
181  		if (!value)
182  			return ERR_PTR(-ENOMEM);
183  		retval = f2fs_getxattr(inode, name_index, "", value,
184  							retval, dpage);
185  	}
186  
187  	if (retval > 0)
188  		acl = f2fs_acl_from_disk(value, retval);
189  	else if (retval == -ENODATA)
190  		acl = NULL;
191  	else
192  		acl = ERR_PTR(retval);
193  	kfree(value);
194  
195  	return acl;
196  }
197  
198  struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
199  {
200  	return __f2fs_get_acl(inode, type, NULL);
201  }
202  
203  static int __f2fs_set_acl(struct inode *inode, int type,
204  			struct posix_acl *acl, struct page *ipage)
205  {
206  	int name_index;
207  	void *value = NULL;
208  	size_t size = 0;
209  	int error;
210  
211  	switch (type) {
212  	case ACL_TYPE_ACCESS:
213  		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
214  		if (acl) {
215  			error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
216  			if (error)
217  				return error;
218  			set_acl_inode(inode, inode->i_mode);
219  		}
220  		break;
221  
222  	case ACL_TYPE_DEFAULT:
223  		name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
224  		if (!S_ISDIR(inode->i_mode))
225  			return acl ? -EACCES : 0;
226  		break;
227  
228  	default:
229  		return -EINVAL;
230  	}
231  
232  	if (acl) {
233  		value = f2fs_acl_to_disk(F2FS_I_SB(inode), acl, &size);
234  		if (IS_ERR(value)) {
235  			clear_inode_flag(inode, FI_ACL_MODE);
236  			return (int)PTR_ERR(value);
237  		}
238  	}
239  
240  	error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0);
241  
242  	kfree(value);
243  	if (!error)
244  		set_cached_acl(inode, type, acl);
245  
246  	clear_inode_flag(inode, FI_ACL_MODE);
247  	return error;
248  }
249  
250  int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
251  {
252  	return __f2fs_set_acl(inode, type, acl, NULL);
253  }
254  
255  /*
256   * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
257   * are copied from posix_acl.c
258   */
259  static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
260  							gfp_t flags)
261  {
262  	struct posix_acl *clone = NULL;
263  
264  	if (acl) {
265  		int size = sizeof(struct posix_acl) + acl->a_count *
266  				sizeof(struct posix_acl_entry);
267  		clone = kmemdup(acl, size, flags);
268  		if (clone)
269  			atomic_set(&clone->a_refcount, 1);
270  	}
271  	return clone;
272  }
273  
274  static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
275  {
276  	struct posix_acl_entry *pa, *pe;
277  	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
278  	umode_t mode = *mode_p;
279  	int not_equiv = 0;
280  
281  	/* assert(atomic_read(acl->a_refcount) == 1); */
282  
283  	FOREACH_ACL_ENTRY(pa, acl, pe) {
284  		switch(pa->e_tag) {
285  		case ACL_USER_OBJ:
286  			pa->e_perm &= (mode >> 6) | ~S_IRWXO;
287  			mode &= (pa->e_perm << 6) | ~S_IRWXU;
288  			break;
289  
290  		case ACL_USER:
291  		case ACL_GROUP:
292  			not_equiv = 1;
293  			break;
294  
295  		case ACL_GROUP_OBJ:
296  			group_obj = pa;
297  			break;
298  
299  		case ACL_OTHER:
300  			pa->e_perm &= mode | ~S_IRWXO;
301  			mode &= pa->e_perm | ~S_IRWXO;
302  			break;
303  
304  		case ACL_MASK:
305  			mask_obj = pa;
306  			not_equiv = 1;
307  			break;
308  
309  		default:
310  			return -EIO;
311  		}
312  	}
313  
314  	if (mask_obj) {
315  		mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
316  		mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
317  	} else {
318  		if (!group_obj)
319  			return -EIO;
320  		group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
321  		mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
322  	}
323  
324  	*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
325          return not_equiv;
326  }
327  
328  static int f2fs_acl_create(struct inode *dir, umode_t *mode,
329  		struct posix_acl **default_acl, struct posix_acl **acl,
330  		struct page *dpage)
331  {
332  	struct posix_acl *p;
333  	struct posix_acl *clone;
334  	int ret;
335  
336  	*acl = NULL;
337  	*default_acl = NULL;
338  
339  	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
340  		return 0;
341  
342  	p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
343  	if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
344  		*mode &= ~current_umask();
345  		return 0;
346  	}
347  	if (IS_ERR(p))
348  		return PTR_ERR(p);
349  
350  	clone = f2fs_acl_clone(p, GFP_NOFS);
351  	if (!clone)
352  		goto no_mem;
353  
354  	ret = f2fs_acl_create_masq(clone, mode);
355  	if (ret < 0)
356  		goto no_mem_clone;
357  
358  	if (ret == 0)
359  		posix_acl_release(clone);
360  	else
361  		*acl = clone;
362  
363  	if (!S_ISDIR(*mode))
364  		posix_acl_release(p);
365  	else
366  		*default_acl = p;
367  
368  	return 0;
369  
370  no_mem_clone:
371  	posix_acl_release(clone);
372  no_mem:
373  	posix_acl_release(p);
374  	return -ENOMEM;
375  }
376  
377  int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
378  							struct page *dpage)
379  {
380  	struct posix_acl *default_acl = NULL, *acl = NULL;
381  	int error = 0;
382  
383  	error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
384  	if (error)
385  		return error;
386  
387  	f2fs_mark_inode_dirty_sync(inode);
388  
389  	if (default_acl) {
390  		error = __f2fs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl,
391  				       ipage);
392  		posix_acl_release(default_acl);
393  	}
394  	if (acl) {
395  		if (!error)
396  			error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl,
397  					       ipage);
398  		posix_acl_release(acl);
399  	}
400  
401  	return error;
402  }
403