1 // SPDX-License-Identifier: GPL-2.0
2 #include "reiserfs.h"
3 #include <linux/errno.h>
4 #include <linux/fs.h>
5 #include <linux/pagemap.h>
6 #include <linux/xattr.h>
7 #include <linux/slab.h>
8 #include "xattr.h"
9 #include <linux/security.h>
10 #include <linux/uaccess.h>
11
12 static int
13 security_get(const struct xattr_handler *handler, struct dentry *unused,
14 struct inode *inode, const char *name, void *buffer, size_t size)
15 {
16 if (IS_PRIVATE(inode))
17 return -EPERM;
18
19 return reiserfs_xattr_get(inode, xattr_full_name(handler, name),
20 buffer, size);
21 }
22
23 static int
24 security_set(const struct xattr_handler *handler,
25 struct mnt_idmap *idmap, struct dentry *unused,
26 struct inode *inode, const char *name, const void *buffer,
27 size_t size, int flags)
28 {
29 if (IS_PRIVATE(inode))
30 return -EPERM;
31
32 return reiserfs_xattr_set(inode,
33 xattr_full_name(handler, name),
34 buffer, size, flags);
35 }
36
37 static bool security_list(struct dentry *dentry)
38 {
39 return !IS_PRIVATE(d_inode(dentry));
40 }
41
42 static int
43 reiserfs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
44 void *fs_info)
45 {
46 struct reiserfs_security_handle *sec = fs_info;
47
48 sec->value = kmemdup(xattr_array->value, xattr_array->value_len,
49 GFP_KERNEL);
50 if (!sec->value)
51 return -ENOMEM;
52
53 sec->name = xattr_array->name;
54 sec->length = xattr_array->value_len;
55 return 0;
56 }
57
58 /* Initializes the security context for a new inode and returns the number
59 * of blocks needed for the transaction. If successful, reiserfs_security
60 * must be released using reiserfs_security_free when the caller is done. */
61 int reiserfs_security_init(struct inode *dir, struct inode *inode,
62 const struct qstr *qstr,
63 struct reiserfs_security_handle *sec)
64 {
65 int blocks = 0;
66 int error;
67
68 sec->name = NULL;
69 sec->value = NULL;
70 sec->length = 0;
71
72 /* Don't add selinux attributes on xattrs - they'll never get used */
73 if (IS_PRIVATE(dir))
74 return 0;
75
76 error = security_inode_init_security(inode, dir, qstr,
77 &reiserfs_initxattrs, sec);
78 if (error) {
79 sec->name = NULL;
80 sec->value = NULL;
81 sec->length = 0;
82 return error;
83 }
84
85 if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
86 blocks = reiserfs_xattr_jcreate_nblocks(inode) +
87 reiserfs_xattr_nblocks(inode, sec->length);
88 /* We don't want to count the directories twice if we have
89 * a default ACL. */
90 REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
91 }
92 return blocks;
93 }
94
95 int reiserfs_security_write(struct reiserfs_transaction_handle *th,
96 struct inode *inode,
97 struct reiserfs_security_handle *sec)
98 {
99 char xattr_name[XATTR_NAME_MAX + 1] = XATTR_SECURITY_PREFIX;
100 int error;
101
102 if (XATTR_SECURITY_PREFIX_LEN + strlen(sec->name) > XATTR_NAME_MAX)
103 return -EINVAL;
104
105 strlcat(xattr_name, sec->name, sizeof(xattr_name));
106
107 error = reiserfs_xattr_set_handle(th, inode, xattr_name, sec->value,
108 sec->length, XATTR_CREATE);
109 if (error == -ENODATA || error == -EOPNOTSUPP)
110 error = 0;
111
112 return error;
113 }
114
115 void reiserfs_security_free(struct reiserfs_security_handle *sec)
116 {
117 kfree(sec->value);
118 sec->name = NULL;
119 sec->value = NULL;
120 }
121
122 const struct xattr_handler reiserfs_xattr_security_handler = {
123 .prefix = XATTR_SECURITY_PREFIX,
124 .get = security_get,
125 .set = security_set,
126 .list = security_list,
127 };
128
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