1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   * fs/f2fs/acl.c
4   *
5   * Copyright (c) 2012 Samsung Electronics Co., Ltd.
6   *             http://www.samsung.com/
7   *
8   * Portions of this code from linux/fs/ext2/acl.c
9   *
10   * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
11   */
12  #include <linux/f2fs_fs.h>
13  #include "f2fs.h"
14  #include "xattr.h"
15  #include "acl.h"
16  
f2fs_acl_size(int count)17  static inline size_t f2fs_acl_size(int count)
18  {
19  	if (count <= 4) {
20  		return sizeof(struct f2fs_acl_header) +
21  			count * sizeof(struct f2fs_acl_entry_short);
22  	} else {
23  		return sizeof(struct f2fs_acl_header) +
24  			4 * sizeof(struct f2fs_acl_entry_short) +
25  			(count - 4) * sizeof(struct f2fs_acl_entry);
26  	}
27  }
28  
f2fs_acl_count(size_t size)29  static inline int f2fs_acl_count(size_t size)
30  {
31  	ssize_t s;
32  
33  	size -= sizeof(struct f2fs_acl_header);
34  	s = size - 4 * sizeof(struct f2fs_acl_entry_short);
35  	if (s < 0) {
36  		if (size % sizeof(struct f2fs_acl_entry_short))
37  			return -1;
38  		return size / sizeof(struct f2fs_acl_entry_short);
39  	} else {
40  		if (s % sizeof(struct f2fs_acl_entry))
41  			return -1;
42  		return s / sizeof(struct f2fs_acl_entry) + 4;
43  	}
44  }
45  
f2fs_acl_from_disk(const char * value,size_t size)46  static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
47  {
48  	int i, count;
49  	struct posix_acl *acl;
50  	struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
51  	struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
52  	const char *end = value + size;
53  
54  	if (size < sizeof(struct f2fs_acl_header))
55  		return ERR_PTR(-EINVAL);
56  
57  	if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
58  		return ERR_PTR(-EINVAL);
59  
60  	count = f2fs_acl_count(size);
61  	if (count < 0)
62  		return ERR_PTR(-EINVAL);
63  	if (count == 0)
64  		return NULL;
65  
66  	acl = posix_acl_alloc(count, GFP_NOFS);
67  	if (!acl)
68  		return ERR_PTR(-ENOMEM);
69  
70  	for (i = 0; i < count; i++) {
71  
72  		if ((char *)entry > end)
73  			goto fail;
74  
75  		acl->a_entries[i].e_tag  = le16_to_cpu(entry->e_tag);
76  		acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
77  
78  		switch (acl->a_entries[i].e_tag) {
79  		case ACL_USER_OBJ:
80  		case ACL_GROUP_OBJ:
81  		case ACL_MASK:
82  		case ACL_OTHER:
83  			entry = (struct f2fs_acl_entry *)((char *)entry +
84  					sizeof(struct f2fs_acl_entry_short));
85  			break;
86  
87  		case ACL_USER:
88  			acl->a_entries[i].e_uid =
89  				make_kuid(&init_user_ns,
90  						le32_to_cpu(entry->e_id));
91  			entry = (struct f2fs_acl_entry *)((char *)entry +
92  					sizeof(struct f2fs_acl_entry));
93  			break;
94  		case ACL_GROUP:
95  			acl->a_entries[i].e_gid =
96  				make_kgid(&init_user_ns,
97  						le32_to_cpu(entry->e_id));
98  			entry = (struct f2fs_acl_entry *)((char *)entry +
99  					sizeof(struct f2fs_acl_entry));
100  			break;
101  		default:
102  			goto fail;
103  		}
104  	}
105  	if ((char *)entry != end)
106  		goto fail;
107  	return acl;
108  fail:
109  	posix_acl_release(acl);
110  	return ERR_PTR(-EINVAL);
111  }
112  
f2fs_acl_to_disk(struct f2fs_sb_info * sbi,const struct posix_acl * acl,size_t * size)113  static void *f2fs_acl_to_disk(struct f2fs_sb_info *sbi,
114  				const struct posix_acl *acl, size_t *size)
115  {
116  	struct f2fs_acl_header *f2fs_acl;
117  	struct f2fs_acl_entry *entry;
118  	int i;
119  
120  	f2fs_acl = f2fs_kmalloc(sbi, sizeof(struct f2fs_acl_header) +
121  			acl->a_count * sizeof(struct f2fs_acl_entry),
122  			GFP_NOFS);
123  	if (!f2fs_acl)
124  		return ERR_PTR(-ENOMEM);
125  
126  	f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
127  	entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
128  
129  	for (i = 0; i < acl->a_count; i++) {
130  
131  		entry->e_tag  = cpu_to_le16(acl->a_entries[i].e_tag);
132  		entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
133  
134  		switch (acl->a_entries[i].e_tag) {
135  		case ACL_USER:
136  			entry->e_id = cpu_to_le32(
137  					from_kuid(&init_user_ns,
138  						acl->a_entries[i].e_uid));
139  			entry = (struct f2fs_acl_entry *)((char *)entry +
140  					sizeof(struct f2fs_acl_entry));
141  			break;
142  		case ACL_GROUP:
143  			entry->e_id = cpu_to_le32(
144  					from_kgid(&init_user_ns,
145  						acl->a_entries[i].e_gid));
146  			entry = (struct f2fs_acl_entry *)((char *)entry +
147  					sizeof(struct f2fs_acl_entry));
148  			break;
149  		case ACL_USER_OBJ:
150  		case ACL_GROUP_OBJ:
151  		case ACL_MASK:
152  		case ACL_OTHER:
153  			entry = (struct f2fs_acl_entry *)((char *)entry +
154  					sizeof(struct f2fs_acl_entry_short));
155  			break;
156  		default:
157  			goto fail;
158  		}
159  	}
160  	*size = f2fs_acl_size(acl->a_count);
161  	return (void *)f2fs_acl;
162  
163  fail:
164  	kfree(f2fs_acl);
165  	return ERR_PTR(-EINVAL);
166  }
167  
__f2fs_get_acl(struct inode * inode,int type,struct page * dpage)168  static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
169  						struct page *dpage)
170  {
171  	int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
172  	void *value = NULL;
173  	struct posix_acl *acl;
174  	int retval;
175  
176  	if (type == ACL_TYPE_ACCESS)
177  		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
178  
179  	retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);
180  	if (retval > 0) {
181  		value = f2fs_kmalloc(F2FS_I_SB(inode), retval, GFP_F2FS_ZERO);
182  		if (!value)
183  			return ERR_PTR(-ENOMEM);
184  		retval = f2fs_getxattr(inode, name_index, "", value,
185  							retval, dpage);
186  	}
187  
188  	if (retval > 0)
189  		acl = f2fs_acl_from_disk(value, retval);
190  	else if (retval == -ENODATA)
191  		acl = NULL;
192  	else
193  		acl = ERR_PTR(retval);
194  	kfree(value);
195  
196  	return acl;
197  }
198  
f2fs_get_acl(struct inode * inode,int type,bool rcu)199  struct posix_acl *f2fs_get_acl(struct inode *inode, int type, bool rcu)
200  {
201  	if (rcu)
202  		return ERR_PTR(-ECHILD);
203  
204  	return __f2fs_get_acl(inode, type, NULL);
205  }
206  
f2fs_acl_update_mode(struct mnt_idmap * idmap,struct inode * inode,umode_t * mode_p,struct posix_acl ** acl)207  static int f2fs_acl_update_mode(struct mnt_idmap *idmap,
208  				struct inode *inode, umode_t *mode_p,
209  				struct posix_acl **acl)
210  {
211  	umode_t mode = inode->i_mode;
212  	int error;
213  
214  	if (is_inode_flag_set(inode, FI_ACL_MODE))
215  		mode = F2FS_I(inode)->i_acl_mode;
216  
217  	error = posix_acl_equiv_mode(*acl, &mode);
218  	if (error < 0)
219  		return error;
220  	if (error == 0)
221  		*acl = NULL;
222  	if (!in_group_or_capable(idmap, inode, i_gid_into_vfsgid(idmap, inode)))
223  		mode &= ~S_ISGID;
224  	*mode_p = mode;
225  	return 0;
226  }
227  
__f2fs_set_acl(struct mnt_idmap * idmap,struct inode * inode,int type,struct posix_acl * acl,struct page * ipage)228  static int __f2fs_set_acl(struct mnt_idmap *idmap,
229  			struct inode *inode, int type,
230  			struct posix_acl *acl, struct page *ipage)
231  {
232  	int name_index;
233  	void *value = NULL;
234  	size_t size = 0;
235  	int error;
236  	umode_t mode = inode->i_mode;
237  
238  	switch (type) {
239  	case ACL_TYPE_ACCESS:
240  		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
241  		if (acl && !ipage) {
242  			error = f2fs_acl_update_mode(idmap, inode,
243  								&mode, &acl);
244  			if (error)
245  				return error;
246  			set_acl_inode(inode, mode);
247  		}
248  		break;
249  
250  	case ACL_TYPE_DEFAULT:
251  		name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
252  		if (!S_ISDIR(inode->i_mode))
253  			return acl ? -EACCES : 0;
254  		break;
255  
256  	default:
257  		return -EINVAL;
258  	}
259  
260  	if (acl) {
261  		value = f2fs_acl_to_disk(F2FS_I_SB(inode), acl, &size);
262  		if (IS_ERR(value)) {
263  			clear_inode_flag(inode, FI_ACL_MODE);
264  			return PTR_ERR(value);
265  		}
266  	}
267  
268  	error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0);
269  
270  	kfree(value);
271  	if (!error)
272  		set_cached_acl(inode, type, acl);
273  
274  	clear_inode_flag(inode, FI_ACL_MODE);
275  	return error;
276  }
277  
f2fs_set_acl(struct mnt_idmap * idmap,struct dentry * dentry,struct posix_acl * acl,int type)278  int f2fs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
279  		 struct posix_acl *acl, int type)
280  {
281  	struct inode *inode = d_inode(dentry);
282  
283  	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
284  		return -EIO;
285  
286  	return __f2fs_set_acl(idmap, inode, type, acl, NULL);
287  }
288  
289  /*
290   * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
291   * are copied from posix_acl.c
292   */
f2fs_acl_clone(const struct posix_acl * acl,gfp_t flags)293  static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
294  							gfp_t flags)
295  {
296  	struct posix_acl *clone = NULL;
297  
298  	if (acl) {
299  		int size = sizeof(struct posix_acl) + acl->a_count *
300  				sizeof(struct posix_acl_entry);
301  		clone = kmemdup(acl, size, flags);
302  		if (clone)
303  			refcount_set(&clone->a_refcount, 1);
304  	}
305  	return clone;
306  }
307  
f2fs_acl_create_masq(struct posix_acl * acl,umode_t * mode_p)308  static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
309  {
310  	struct posix_acl_entry *pa, *pe;
311  	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
312  	umode_t mode = *mode_p;
313  	int not_equiv = 0;
314  
315  	/* assert(atomic_read(acl->a_refcount) == 1); */
316  
317  	FOREACH_ACL_ENTRY(pa, acl, pe) {
318  		switch (pa->e_tag) {
319  		case ACL_USER_OBJ:
320  			pa->e_perm &= (mode >> 6) | ~S_IRWXO;
321  			mode &= (pa->e_perm << 6) | ~S_IRWXU;
322  			break;
323  
324  		case ACL_USER:
325  		case ACL_GROUP:
326  			not_equiv = 1;
327  			break;
328  
329  		case ACL_GROUP_OBJ:
330  			group_obj = pa;
331  			break;
332  
333  		case ACL_OTHER:
334  			pa->e_perm &= mode | ~S_IRWXO;
335  			mode &= pa->e_perm | ~S_IRWXO;
336  			break;
337  
338  		case ACL_MASK:
339  			mask_obj = pa;
340  			not_equiv = 1;
341  			break;
342  
343  		default:
344  			return -EIO;
345  		}
346  	}
347  
348  	if (mask_obj) {
349  		mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
350  		mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
351  	} else {
352  		if (!group_obj)
353  			return -EIO;
354  		group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
355  		mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
356  	}
357  
358  	*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
359  	return not_equiv;
360  }
361  
f2fs_acl_create(struct inode * dir,umode_t * mode,struct posix_acl ** default_acl,struct posix_acl ** acl,struct page * dpage)362  static int f2fs_acl_create(struct inode *dir, umode_t *mode,
363  		struct posix_acl **default_acl, struct posix_acl **acl,
364  		struct page *dpage)
365  {
366  	struct posix_acl *p;
367  	struct posix_acl *clone;
368  	int ret;
369  
370  	*acl = NULL;
371  	*default_acl = NULL;
372  
373  	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
374  		return 0;
375  
376  	p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
377  	if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
378  		*mode &= ~current_umask();
379  		return 0;
380  	}
381  	if (IS_ERR(p))
382  		return PTR_ERR(p);
383  
384  	clone = f2fs_acl_clone(p, GFP_NOFS);
385  	if (!clone) {
386  		ret = -ENOMEM;
387  		goto release_acl;
388  	}
389  
390  	ret = f2fs_acl_create_masq(clone, mode);
391  	if (ret < 0)
392  		goto release_clone;
393  
394  	if (ret == 0)
395  		posix_acl_release(clone);
396  	else
397  		*acl = clone;
398  
399  	if (!S_ISDIR(*mode))
400  		posix_acl_release(p);
401  	else
402  		*default_acl = p;
403  
404  	return 0;
405  
406  release_clone:
407  	posix_acl_release(clone);
408  release_acl:
409  	posix_acl_release(p);
410  	return ret;
411  }
412  
f2fs_init_acl(struct inode * inode,struct inode * dir,struct page * ipage,struct page * dpage)413  int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
414  							struct page *dpage)
415  {
416  	struct posix_acl *default_acl = NULL, *acl = NULL;
417  	int error;
418  
419  	error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
420  	if (error)
421  		return error;
422  
423  	f2fs_mark_inode_dirty_sync(inode, true);
424  
425  	if (default_acl) {
426  		error = __f2fs_set_acl(NULL, inode, ACL_TYPE_DEFAULT, default_acl,
427  				       ipage);
428  		posix_acl_release(default_acl);
429  	} else {
430  		inode->i_default_acl = NULL;
431  	}
432  	if (acl) {
433  		if (!error)
434  			error = __f2fs_set_acl(NULL, inode, ACL_TYPE_ACCESS, acl,
435  					       ipage);
436  		posix_acl_release(acl);
437  	} else {
438  		inode->i_acl = NULL;
439  	}
440  
441  	return error;
442  }
443