1 /*
2 * FUSE: Filesystem in Userspace
3 * Copyright (C) 2016 Canonical Ltd. <seth.forshee@canonical.com>
4 *
5 * This program can be distributed under the terms of the GNU GPL.
6 * See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/posix_acl.h>
12 #include <linux/posix_acl_xattr.h>
13
fuse_get_acl(struct inode * inode,int type)14 struct posix_acl *fuse_get_acl(struct inode *inode, int type)
15 {
16 struct fuse_conn *fc = get_fuse_conn(inode);
17 int size;
18 const char *name;
19 void *value = NULL;
20 struct posix_acl *acl;
21
22 if (!fc->posix_acl || fc->no_getxattr)
23 return NULL;
24
25 if (type == ACL_TYPE_ACCESS)
26 name = XATTR_NAME_POSIX_ACL_ACCESS;
27 else if (type == ACL_TYPE_DEFAULT)
28 name = XATTR_NAME_POSIX_ACL_DEFAULT;
29 else
30 return ERR_PTR(-EOPNOTSUPP);
31
32 value = kmalloc(PAGE_SIZE, GFP_KERNEL);
33 if (!value)
34 return ERR_PTR(-ENOMEM);
35 size = fuse_getxattr(inode, name, value, PAGE_SIZE);
36 if (size > 0)
37 acl = posix_acl_from_xattr(fc->user_ns, value, size);
38 else if ((size == 0) || (size == -ENODATA) ||
39 (size == -EOPNOTSUPP && fc->no_getxattr))
40 acl = NULL;
41 else if (size == -ERANGE)
42 acl = ERR_PTR(-E2BIG);
43 else
44 acl = ERR_PTR(size);
45
46 kfree(value);
47 return acl;
48 }
49
fuse_set_acl(struct inode * inode,struct posix_acl * acl,int type)50 int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type)
51 {
52 struct fuse_conn *fc = get_fuse_conn(inode);
53 const char *name;
54 int ret;
55
56 if (!fc->posix_acl || fc->no_setxattr)
57 return -EOPNOTSUPP;
58
59 if (type == ACL_TYPE_ACCESS)
60 name = XATTR_NAME_POSIX_ACL_ACCESS;
61 else if (type == ACL_TYPE_DEFAULT)
62 name = XATTR_NAME_POSIX_ACL_DEFAULT;
63 else
64 return -EINVAL;
65
66 if (acl) {
67 /*
68 * Fuse userspace is responsible for updating access
69 * permissions in the inode, if needed. fuse_setxattr
70 * invalidates the inode attributes, which will force
71 * them to be refreshed the next time they are used,
72 * and it also updates i_ctime.
73 */
74 size_t size = posix_acl_xattr_size(acl->a_count);
75 void *value;
76
77 if (size > PAGE_SIZE)
78 return -E2BIG;
79
80 value = kmalloc(size, GFP_KERNEL);
81 if (!value)
82 return -ENOMEM;
83
84 ret = posix_acl_to_xattr(fc->user_ns, acl, value, size);
85 if (ret < 0) {
86 kfree(value);
87 return ret;
88 }
89
90 ret = fuse_setxattr(inode, name, value, size, 0);
91 kfree(value);
92 } else {
93 ret = fuse_removexattr(inode, name);
94 }
95 forget_all_cached_acls(inode);
96 fuse_invalidate_attr(inode);
97
98 return ret;
99 }
100