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
12static int
13security_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
23static int
24security_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
37static bool security_list(struct dentry *dentry)
38{
39	return !IS_PRIVATE(d_inode(dentry));
40}
41
42static int
43reiserfs_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. */
61int 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
95int 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
115void reiserfs_security_free(struct reiserfs_security_handle *sec)
116{
117	kfree(sec->value);
118	sec->name = NULL;
119	sec->value = NULL;
120}
121
122const 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