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
15 #include "ctree.h"
16 #include "btrfs_inode.h"
17 #include "xattr.h"
18
btrfs_get_acl(struct inode * inode,int type,bool rcu)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(-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(-EINVAL);
38 }
39
40 size = btrfs_getxattr(inode, name, NULL, 0);
41 if (size > 0) {
42 value = kzalloc(size, GFP_KERNEL);
43 if (!value)
44 return ERR_PTR(-ENOMEM);
45 size = btrfs_getxattr(inode, name, value, size);
46 }
47 if (size > 0)
48 acl = posix_acl_from_xattr(&init_user_ns, value, size);
49 else if (size == -ENODATA || size == 0)
50 acl = NULL;
51 else
52 acl = ERR_PTR(size);
53 kfree(value);
54
55 return acl;
56 }
57
__btrfs_set_acl(struct btrfs_trans_handle * trans,struct user_namespace * mnt_userns,struct inode * inode,struct posix_acl * acl,int type)58 static int __btrfs_set_acl(struct btrfs_trans_handle *trans,
59 struct user_namespace *mnt_userns,
60 struct inode *inode, struct posix_acl *acl, int type)
61 {
62 int ret, size = 0;
63 const char *name;
64 char *value = NULL;
65
66 switch (type) {
67 case ACL_TYPE_ACCESS:
68 name = XATTR_NAME_POSIX_ACL_ACCESS;
69 break;
70 case ACL_TYPE_DEFAULT:
71 if (!S_ISDIR(inode->i_mode))
72 return acl ? -EINVAL : 0;
73 name = XATTR_NAME_POSIX_ACL_DEFAULT;
74 break;
75 default:
76 return -EINVAL;
77 }
78
79 if (acl) {
80 unsigned int nofs_flag;
81
82 size = posix_acl_xattr_size(acl->a_count);
83 /*
84 * We're holding a transaction handle, so use a NOFS memory
85 * allocation context to avoid deadlock if reclaim happens.
86 */
87 nofs_flag = memalloc_nofs_save();
88 value = kmalloc(size, GFP_KERNEL);
89 memalloc_nofs_restore(nofs_flag);
90 if (!value) {
91 ret = -ENOMEM;
92 goto out;
93 }
94
95 ret = posix_acl_to_xattr(&init_user_ns, acl, value, size);
96 if (ret < 0)
97 goto out;
98 }
99
100 if (trans)
101 ret = btrfs_setxattr(trans, inode, name, value, size, 0);
102 else
103 ret = btrfs_setxattr_trans(inode, name, value, size, 0);
104
105 out:
106 kfree(value);
107
108 if (!ret)
109 set_cached_acl(inode, type, acl);
110
111 return ret;
112 }
113
btrfs_set_acl(struct user_namespace * mnt_userns,struct inode * inode,struct posix_acl * acl,int type)114 int btrfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
115 struct posix_acl *acl, int type)
116 {
117 int ret;
118 umode_t old_mode = inode->i_mode;
119
120 if (type == ACL_TYPE_ACCESS && acl) {
121 ret = posix_acl_update_mode(mnt_userns, inode,
122 &inode->i_mode, &acl);
123 if (ret)
124 return ret;
125 }
126 ret = __btrfs_set_acl(NULL, mnt_userns, inode, acl, type);
127 if (ret)
128 inode->i_mode = old_mode;
129 return ret;
130 }
131
btrfs_init_acl(struct btrfs_trans_handle * trans,struct inode * inode,struct inode * dir)132 int btrfs_init_acl(struct btrfs_trans_handle *trans,
133 struct inode *inode, struct inode *dir)
134 {
135 struct posix_acl *default_acl, *acl;
136 int ret = 0;
137
138 /* this happens with subvols */
139 if (!dir)
140 return 0;
141
142 ret = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
143 if (ret)
144 return ret;
145
146 if (default_acl) {
147 ret = __btrfs_set_acl(trans, &init_user_ns, inode, default_acl,
148 ACL_TYPE_DEFAULT);
149 posix_acl_release(default_acl);
150 }
151
152 if (acl) {
153 if (!ret)
154 ret = __btrfs_set_acl(trans, &init_user_ns, inode, acl,
155 ACL_TYPE_ACCESS);
156 posix_acl_release(acl);
157 }
158
159 if (!default_acl && !acl)
160 cache_no_acl(inode);
161 return ret;
162 }
163
