1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * FUSE: Filesystem in Userspace
3*4882a593Smuzhiyun * Copyright (C) 2016 Canonical Ltd. <seth.forshee@canonical.com>
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * This program can be distributed under the terms of the GNU GPL.
6*4882a593Smuzhiyun * See the file COPYING.
7*4882a593Smuzhiyun */
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #include "fuse_i.h"
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #include <linux/posix_acl.h>
12*4882a593Smuzhiyun #include <linux/posix_acl_xattr.h>
13*4882a593Smuzhiyun
fuse_get_acl(struct inode * inode,int type)14*4882a593Smuzhiyun struct posix_acl *fuse_get_acl(struct inode *inode, int type)
15*4882a593Smuzhiyun {
16*4882a593Smuzhiyun struct fuse_conn *fc = get_fuse_conn(inode);
17*4882a593Smuzhiyun int size;
18*4882a593Smuzhiyun const char *name;
19*4882a593Smuzhiyun void *value = NULL;
20*4882a593Smuzhiyun struct posix_acl *acl;
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun if (fuse_is_bad(inode))
23*4882a593Smuzhiyun return ERR_PTR(-EIO);
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun if (!fc->posix_acl || fc->no_getxattr)
26*4882a593Smuzhiyun return NULL;
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun if (type == ACL_TYPE_ACCESS)
29*4882a593Smuzhiyun name = XATTR_NAME_POSIX_ACL_ACCESS;
30*4882a593Smuzhiyun else if (type == ACL_TYPE_DEFAULT)
31*4882a593Smuzhiyun name = XATTR_NAME_POSIX_ACL_DEFAULT;
32*4882a593Smuzhiyun else
33*4882a593Smuzhiyun return ERR_PTR(-EOPNOTSUPP);
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun value = kmalloc(PAGE_SIZE, GFP_KERNEL);
36*4882a593Smuzhiyun if (!value)
37*4882a593Smuzhiyun return ERR_PTR(-ENOMEM);
38*4882a593Smuzhiyun size = fuse_getxattr(inode, name, value, PAGE_SIZE);
39*4882a593Smuzhiyun if (size > 0)
40*4882a593Smuzhiyun acl = posix_acl_from_xattr(fc->user_ns, value, size);
41*4882a593Smuzhiyun else if ((size == 0) || (size == -ENODATA) ||
42*4882a593Smuzhiyun (size == -EOPNOTSUPP && fc->no_getxattr))
43*4882a593Smuzhiyun acl = NULL;
44*4882a593Smuzhiyun else if (size == -ERANGE)
45*4882a593Smuzhiyun acl = ERR_PTR(-E2BIG);
46*4882a593Smuzhiyun else
47*4882a593Smuzhiyun acl = ERR_PTR(size);
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun kfree(value);
50*4882a593Smuzhiyun return acl;
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun
fuse_set_acl(struct inode * inode,struct posix_acl * acl,int type)53*4882a593Smuzhiyun int fuse_set_acl(struct inode *inode, struct posix_acl *acl, int type)
54*4882a593Smuzhiyun {
55*4882a593Smuzhiyun struct fuse_conn *fc = get_fuse_conn(inode);
56*4882a593Smuzhiyun const char *name;
57*4882a593Smuzhiyun int ret;
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun if (fuse_is_bad(inode))
60*4882a593Smuzhiyun return -EIO;
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun if (!fc->posix_acl || fc->no_setxattr)
63*4882a593Smuzhiyun return -EOPNOTSUPP;
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun if (type == ACL_TYPE_ACCESS)
66*4882a593Smuzhiyun name = XATTR_NAME_POSIX_ACL_ACCESS;
67*4882a593Smuzhiyun else if (type == ACL_TYPE_DEFAULT)
68*4882a593Smuzhiyun name = XATTR_NAME_POSIX_ACL_DEFAULT;
69*4882a593Smuzhiyun else
70*4882a593Smuzhiyun return -EINVAL;
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun if (acl) {
73*4882a593Smuzhiyun /*
74*4882a593Smuzhiyun * Fuse userspace is responsible for updating access
75*4882a593Smuzhiyun * permissions in the inode, if needed. fuse_setxattr
76*4882a593Smuzhiyun * invalidates the inode attributes, which will force
77*4882a593Smuzhiyun * them to be refreshed the next time they are used,
78*4882a593Smuzhiyun * and it also updates i_ctime.
79*4882a593Smuzhiyun */
80*4882a593Smuzhiyun size_t size = posix_acl_xattr_size(acl->a_count);
81*4882a593Smuzhiyun void *value;
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun if (size > PAGE_SIZE)
84*4882a593Smuzhiyun return -E2BIG;
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun value = kmalloc(size, GFP_KERNEL);
87*4882a593Smuzhiyun if (!value)
88*4882a593Smuzhiyun return -ENOMEM;
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun ret = posix_acl_to_xattr(fc->user_ns, acl, value, size);
91*4882a593Smuzhiyun if (ret < 0) {
92*4882a593Smuzhiyun kfree(value);
93*4882a593Smuzhiyun return ret;
94*4882a593Smuzhiyun }
95*4882a593Smuzhiyun
96*4882a593Smuzhiyun ret = fuse_setxattr(inode, name, value, size, 0);
97*4882a593Smuzhiyun kfree(value);
98*4882a593Smuzhiyun } else {
99*4882a593Smuzhiyun ret = fuse_removexattr(inode, name);
100*4882a593Smuzhiyun }
101*4882a593Smuzhiyun forget_all_cached_acls(inode);
102*4882a593Smuzhiyun fuse_invalidate_attr(inode);
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun return ret;
105*4882a593Smuzhiyun }
106