xref: /openbmc/linux/fs/reiserfs/xattr_security.c (revision abfbd895)
1 #include "reiserfs.h"
2 #include <linux/errno.h>
3 #include <linux/fs.h>
4 #include <linux/pagemap.h>
5 #include <linux/xattr.h>
6 #include <linux/slab.h>
7 #include "xattr.h"
8 #include <linux/security.h>
9 #include <linux/uaccess.h>
10 
11 static int
12 security_get(const struct xattr_handler *handler, struct dentry *dentry,
13 	     const char *name, void *buffer, size_t size)
14 {
15 	if (strlen(name) < sizeof(XATTR_SECURITY_PREFIX))
16 		return -EINVAL;
17 
18 	if (IS_PRIVATE(d_inode(dentry)))
19 		return -EPERM;
20 
21 	return reiserfs_xattr_get(d_inode(dentry), name, buffer, size);
22 }
23 
24 static int
25 security_set(const struct xattr_handler *handler, struct dentry *dentry,
26 	     const char *name, const void *buffer, size_t size, int flags)
27 {
28 	if (strlen(name) < sizeof(XATTR_SECURITY_PREFIX))
29 		return -EINVAL;
30 
31 	if (IS_PRIVATE(d_inode(dentry)))
32 		return -EPERM;
33 
34 	return reiserfs_xattr_set(d_inode(dentry), name, buffer, size, flags);
35 }
36 
37 static size_t security_list(const struct xattr_handler *handler,
38 			    struct dentry *dentry, char *list, size_t list_len,
39 			    const char *name, size_t namelen)
40 {
41 	const size_t len = namelen + 1;
42 
43 	if (IS_PRIVATE(d_inode(dentry)))
44 		return 0;
45 
46 	if (list && len <= list_len) {
47 		memcpy(list, name, namelen);
48 		list[namelen] = '\0';
49 	}
50 
51 	return len;
52 }
53 
54 /* Initializes the security context for a new inode and returns the number
55  * of blocks needed for the transaction. If successful, reiserfs_security
56  * must be released using reiserfs_security_free when the caller is done. */
57 int reiserfs_security_init(struct inode *dir, struct inode *inode,
58 			   const struct qstr *qstr,
59 			   struct reiserfs_security_handle *sec)
60 {
61 	int blocks = 0;
62 	int error;
63 
64 	sec->name = NULL;
65 
66 	/* Don't add selinux attributes on xattrs - they'll never get used */
67 	if (IS_PRIVATE(dir))
68 		return 0;
69 
70 	error = security_old_inode_init_security(inode, dir, qstr, &sec->name,
71 						 &sec->value, &sec->length);
72 	if (error) {
73 		if (error == -EOPNOTSUPP)
74 			error = 0;
75 
76 		sec->name = NULL;
77 		sec->value = NULL;
78 		sec->length = 0;
79 		return error;
80 	}
81 
82 	if (sec->length && reiserfs_xattrs_initialized(inode->i_sb)) {
83 		blocks = reiserfs_xattr_jcreate_nblocks(inode) +
84 			 reiserfs_xattr_nblocks(inode, sec->length);
85 		/* We don't want to count the directories twice if we have
86 		 * a default ACL. */
87 		REISERFS_I(inode)->i_flags |= i_has_xattr_dir;
88 	}
89 	return blocks;
90 }
91 
92 int reiserfs_security_write(struct reiserfs_transaction_handle *th,
93 			    struct inode *inode,
94 			    struct reiserfs_security_handle *sec)
95 {
96 	int error;
97 	if (strlen(sec->name) < sizeof(XATTR_SECURITY_PREFIX))
98 		return -EINVAL;
99 
100 	error = reiserfs_xattr_set_handle(th, inode, sec->name, sec->value,
101 					  sec->length, XATTR_CREATE);
102 	if (error == -ENODATA || error == -EOPNOTSUPP)
103 		error = 0;
104 
105 	return error;
106 }
107 
108 void reiserfs_security_free(struct reiserfs_security_handle *sec)
109 {
110 	kfree(sec->name);
111 	kfree(sec->value);
112 	sec->name = NULL;
113 	sec->value = NULL;
114 }
115 
116 const struct xattr_handler reiserfs_xattr_security_handler = {
117 	.prefix = XATTR_SECURITY_PREFIX,
118 	.get = security_get,
119 	.set = security_set,
120 	.list = security_list,
121 };
122