1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Copyright (C) 2007 Red Hat. All rights reserved. |
4 | */ |
5 | |
6 | #include <linux/fs.h> |
7 | #include <linux/string.h> |
8 | #include <linux/xattr.h> |
9 | #include <linux/posix_acl_xattr.h> |
10 | #include <linux/posix_acl.h> |
11 | #include <linux/sched.h> |
12 | #include <linux/sched/mm.h> |
13 | #include <linux/slab.h> |
14 | #include "ctree.h" |
15 | #include "xattr.h" |
16 | #include "acl.h" |
17 | |
18 | struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu) |
19 | { |
20 | int size; |
21 | const char *name; |
22 | char *value = NULL; |
23 | struct posix_acl *acl; |
24 | |
25 | if (rcu) |
26 | return ERR_PTR(error: -ECHILD); |
27 | |
28 | switch (type) { |
29 | case ACL_TYPE_ACCESS: |
30 | name = XATTR_NAME_POSIX_ACL_ACCESS; |
31 | break; |
32 | case ACL_TYPE_DEFAULT: |
33 | name = XATTR_NAME_POSIX_ACL_DEFAULT; |
34 | break; |
35 | default: |
36 | return ERR_PTR(error: -EINVAL); |
37 | } |
38 | |
39 | size = btrfs_getxattr(inode, name, NULL, size: 0); |
40 | if (size > 0) { |
41 | value = kzalloc(size, GFP_KERNEL); |
42 | if (!value) |
43 | return ERR_PTR(error: -ENOMEM); |
44 | size = btrfs_getxattr(inode, name, buffer: value, size); |
45 | } |
46 | if (size > 0) |
47 | acl = posix_acl_from_xattr(user_ns: &init_user_ns, value, size); |
48 | else if (size == -ENODATA || size == 0) |
49 | acl = NULL; |
50 | else |
51 | acl = ERR_PTR(error: size); |
52 | kfree(objp: value); |
53 | |
54 | return acl; |
55 | } |
56 | |
57 | int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode, |
58 | struct posix_acl *acl, int type) |
59 | { |
60 | int ret, size = 0; |
61 | const char *name; |
62 | char *value = NULL; |
63 | |
64 | switch (type) { |
65 | case ACL_TYPE_ACCESS: |
66 | name = XATTR_NAME_POSIX_ACL_ACCESS; |
67 | break; |
68 | case ACL_TYPE_DEFAULT: |
69 | if (!S_ISDIR(inode->i_mode)) |
70 | return acl ? -EINVAL : 0; |
71 | name = XATTR_NAME_POSIX_ACL_DEFAULT; |
72 | break; |
73 | default: |
74 | return -EINVAL; |
75 | } |
76 | |
77 | if (acl) { |
78 | unsigned int nofs_flag; |
79 | |
80 | size = posix_acl_xattr_size(count: acl->a_count); |
81 | /* |
82 | * We're holding a transaction handle, so use a NOFS memory |
83 | * allocation context to avoid deadlock if reclaim happens. |
84 | */ |
85 | nofs_flag = memalloc_nofs_save(); |
86 | value = kmalloc(size, GFP_KERNEL); |
87 | memalloc_nofs_restore(flags: nofs_flag); |
88 | if (!value) { |
89 | ret = -ENOMEM; |
90 | goto out; |
91 | } |
92 | |
93 | ret = posix_acl_to_xattr(user_ns: &init_user_ns, acl, buffer: value, size); |
94 | if (ret < 0) |
95 | goto out; |
96 | } |
97 | |
98 | if (trans) |
99 | ret = btrfs_setxattr(trans, inode, name, value, size, flags: 0); |
100 | else |
101 | ret = btrfs_setxattr_trans(inode, name, value, size, flags: 0); |
102 | |
103 | out: |
104 | kfree(objp: value); |
105 | |
106 | if (!ret) |
107 | set_cached_acl(inode, type, acl); |
108 | |
109 | return ret; |
110 | } |
111 | |
112 | int btrfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, |
113 | struct posix_acl *acl, int type) |
114 | { |
115 | int ret; |
116 | struct inode *inode = d_inode(dentry); |
117 | umode_t old_mode = inode->i_mode; |
118 | |
119 | if (type == ACL_TYPE_ACCESS && acl) { |
120 | ret = posix_acl_update_mode(idmap, inode, |
121 | &inode->i_mode, &acl); |
122 | if (ret) |
123 | return ret; |
124 | } |
125 | ret = __btrfs_set_acl(NULL, inode, acl, type); |
126 | if (ret) |
127 | inode->i_mode = old_mode; |
128 | return ret; |
129 | } |
130 | |