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 "btrfs_inode.h" |
16 | #include "xattr.h" |
17 | #include "acl.h" |
18 | |
19 | struct posix_acl *btrfs_get_acl(struct inode *inode, int type, bool rcu) |
20 | { |
21 | int size; |
22 | const char *name; |
23 | char *value = NULL; |
24 | struct posix_acl *acl; |
25 | |
26 | if (rcu) |
27 | return ERR_PTR(error: -ECHILD); |
28 | |
29 | switch (type) { |
30 | case ACL_TYPE_ACCESS: |
31 | name = XATTR_NAME_POSIX_ACL_ACCESS; |
32 | break; |
33 | case ACL_TYPE_DEFAULT: |
34 | name = XATTR_NAME_POSIX_ACL_DEFAULT; |
35 | break; |
36 | default: |
37 | return ERR_PTR(error: -EINVAL); |
38 | } |
39 | |
40 | size = btrfs_getxattr(inode, name, NULL, size: 0); |
41 | if (size > 0) { |
42 | value = kzalloc(size, GFP_KERNEL); |
43 | if (!value) |
44 | return ERR_PTR(error: -ENOMEM); |
45 | size = btrfs_getxattr(inode, name, buffer: value, size); |
46 | } |
47 | if (size > 0) |
48 | acl = posix_acl_from_xattr(user_ns: &init_user_ns, value, size); |
49 | else if (size == -ENODATA || size == 0) |
50 | acl = NULL; |
51 | else |
52 | acl = ERR_PTR(error: size); |
53 | kfree(objp: value); |
54 | |
55 | return acl; |
56 | } |
57 | |
58 | int __btrfs_set_acl(struct btrfs_trans_handle *trans, struct inode *inode, |
59 | struct posix_acl *acl, int type) |
60 | { |
61 | int ret, size = 0; |
62 | const char *name; |
63 | char *value = NULL; |
64 | |
65 | switch (type) { |
66 | case ACL_TYPE_ACCESS: |
67 | name = XATTR_NAME_POSIX_ACL_ACCESS; |
68 | break; |
69 | case ACL_TYPE_DEFAULT: |
70 | if (!S_ISDIR(inode->i_mode)) |
71 | return acl ? -EINVAL : 0; |
72 | name = XATTR_NAME_POSIX_ACL_DEFAULT; |
73 | break; |
74 | default: |
75 | return -EINVAL; |
76 | } |
77 | |
78 | if (acl) { |
79 | unsigned int nofs_flag; |
80 | |
81 | size = posix_acl_xattr_size(count: acl->a_count); |
82 | /* |
83 | * We're holding a transaction handle, so use a NOFS memory |
84 | * allocation context to avoid deadlock if reclaim happens. |
85 | */ |
86 | nofs_flag = memalloc_nofs_save(); |
87 | value = kmalloc(size, GFP_KERNEL); |
88 | memalloc_nofs_restore(flags: nofs_flag); |
89 | if (!value) { |
90 | ret = -ENOMEM; |
91 | goto out; |
92 | } |
93 | |
94 | ret = posix_acl_to_xattr(user_ns: &init_user_ns, acl, buffer: value, size); |
95 | if (ret < 0) |
96 | goto out; |
97 | } |
98 | |
99 | if (trans) |
100 | ret = btrfs_setxattr(trans, inode, name, value, size, flags: 0); |
101 | else |
102 | ret = btrfs_setxattr_trans(inode, name, value, size, flags: 0); |
103 | |
104 | out: |
105 | kfree(objp: value); |
106 | |
107 | if (!ret) |
108 | set_cached_acl(inode, type, acl); |
109 | |
110 | return ret; |
111 | } |
112 | |
113 | int btrfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, |
114 | struct posix_acl *acl, int type) |
115 | { |
116 | int ret; |
117 | struct inode *inode = d_inode(dentry); |
118 | umode_t old_mode = inode->i_mode; |
119 | |
120 | if (type == ACL_TYPE_ACCESS && acl) { |
121 | ret = posix_acl_update_mode(idmap, inode, |
122 | &inode->i_mode, &acl); |
123 | if (ret) |
124 | return ret; |
125 | } |
126 | ret = __btrfs_set_acl(NULL, inode, acl, type); |
127 | if (ret) |
128 | inode->i_mode = old_mode; |
129 | return ret; |
130 | } |
131 | |