1// SPDX-License-Identifier: LGPL-2.1
2/*
3 * Copyright IBM Corporation, 2010
4 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
5 */
6
7#include <linux/module.h>
8#include <linux/fs.h>
9#include <net/9p/9p.h>
10#include <net/9p/client.h>
11#include <linux/slab.h>
12#include <linux/sched.h>
13#include <linux/posix_acl_xattr.h>
14#include "xattr.h"
15#include "acl.h"
16#include "v9fs.h"
17#include "v9fs_vfs.h"
18#include "fid.h"
19
20static struct posix_acl *v9fs_fid_get_acl(struct p9_fid *fid, const char *name)
21{
22	ssize_t size;
23	void *value = NULL;
24	struct posix_acl *acl = NULL;
25
26	size = v9fs_fid_xattr_get(fid, name, NULL, 0);
27	if (size < 0)
28		return ERR_PTR(size);
29	if (size == 0)
30		return ERR_PTR(-ENODATA);
31
32	value = kzalloc(size, GFP_NOFS);
33	if (!value)
34		return ERR_PTR(-ENOMEM);
35
36	size = v9fs_fid_xattr_get(fid, name, value, size);
37	if (size < 0)
38		acl = ERR_PTR(size);
39	else if (size == 0)
40		acl = ERR_PTR(-ENODATA);
41	else
42		acl = posix_acl_from_xattr(&init_user_ns, value, size);
43	kfree(value);
44	return acl;
45}
46
47static struct posix_acl *v9fs_acl_get(struct dentry *dentry, const char *name)
48{
49	struct p9_fid *fid;
50	struct posix_acl *acl = NULL;
51
52	fid = v9fs_fid_lookup(dentry);
53	if (IS_ERR(fid))
54		return ERR_CAST(fid);
55
56	acl = v9fs_fid_get_acl(fid, name);
57	p9_fid_put(fid);
58	return acl;
59}
60
61static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, const char *name)
62{
63	int retval;
64	struct posix_acl *acl = NULL;
65
66	acl = v9fs_fid_get_acl(fid, name);
67	if (!IS_ERR(acl))
68		return acl;
69
70	retval = PTR_ERR(acl);
71	if (retval == -ENODATA || retval == -ENOSYS || retval == -EOPNOTSUPP)
72		return NULL;
73
74	/* map everything else to -EIO */
75	return ERR_PTR(-EIO);
76}
77
78int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
79{
80	int retval = 0;
81	struct posix_acl *pacl, *dacl;
82	struct v9fs_session_info *v9ses;
83
84	v9ses = v9fs_inode2v9ses(inode);
85	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
86			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
87		set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
88		set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
89		return 0;
90	}
91	/* get the default/access acl values and cache them */
92	dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT);
93	pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS);
94
95	if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
96		set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
97		set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
98	} else
99		retval = -EIO;
100
101	if (!IS_ERR(dacl))
102		posix_acl_release(dacl);
103
104	if (!IS_ERR(pacl))
105		posix_acl_release(pacl);
106
107	return retval;
108}
109
110static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
111{
112	struct posix_acl *acl;
113	/*
114	 * 9p Always cache the acl value when
115	 * instantiating the inode (v9fs_inode_from_fid)
116	 */
117	acl = get_cached_acl(inode, type);
118	BUG_ON(is_uncached_acl(acl));
119	return acl;
120}
121
122struct posix_acl *v9fs_iop_get_inode_acl(struct inode *inode, int type, bool rcu)
123{
124	struct v9fs_session_info *v9ses;
125
126	if (rcu)
127		return ERR_PTR(-ECHILD);
128
129	v9ses = v9fs_inode2v9ses(inode);
130	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
131			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
132		/*
133		 * On access = client  and acl = on mode get the acl
134		 * values from the server
135		 */
136		return NULL;
137	}
138	return v9fs_get_cached_acl(inode, type);
139
140}
141
142struct posix_acl *v9fs_iop_get_acl(struct mnt_idmap *idmap,
143				   struct dentry *dentry, int type)
144{
145	struct v9fs_session_info *v9ses;
146
147	v9ses = v9fs_dentry2v9ses(dentry);
148	/* We allow set/get/list of acl when access=client is not specified. */
149	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
150		return v9fs_acl_get(dentry, posix_acl_xattr_name(type));
151	return v9fs_get_cached_acl(d_inode(dentry), type);
152}
153
154int v9fs_iop_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
155		     struct posix_acl *acl, int type)
156{
157	int retval;
158	size_t size = 0;
159	void *value = NULL;
160	const char *acl_name;
161	struct v9fs_session_info *v9ses;
162	struct inode *inode = d_inode(dentry);
163
164	if (acl) {
165		retval = posix_acl_valid(inode->i_sb->s_user_ns, acl);
166		if (retval)
167			goto err_out;
168
169		size = posix_acl_xattr_size(acl->a_count);
170
171		value = kzalloc(size, GFP_NOFS);
172		if (!value) {
173			retval = -ENOMEM;
174			goto err_out;
175		}
176
177		retval = posix_acl_to_xattr(&init_user_ns, acl, value, size);
178		if (retval < 0)
179			goto err_out;
180	}
181
182	/*
183	 * set the attribute on the remote. Without even looking at the
184	 * xattr value. We leave it to the server to validate
185	 */
186	acl_name = posix_acl_xattr_name(type);
187	v9ses = v9fs_dentry2v9ses(dentry);
188	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
189		retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
190		goto err_out;
191	}
192
193	if (S_ISLNK(inode->i_mode)) {
194		retval = -EOPNOTSUPP;
195		goto err_out;
196	}
197
198	if (!inode_owner_or_capable(&nop_mnt_idmap, inode)) {
199		retval = -EPERM;
200		goto err_out;
201	}
202
203	switch (type) {
204	case ACL_TYPE_ACCESS:
205		if (acl) {
206			struct iattr iattr = {};
207			struct posix_acl *acl_mode = acl;
208
209			retval = posix_acl_update_mode(&nop_mnt_idmap, inode,
210						       &iattr.ia_mode,
211						       &acl_mode);
212			if (retval)
213				goto err_out;
214			if (!acl_mode) {
215				/*
216				 * ACL can be represented by the mode bits.
217				 * So don't update ACL below.
218				 */
219				kfree(value);
220				value = NULL;
221				size = 0;
222			}
223			iattr.ia_valid = ATTR_MODE;
224			/*
225			 * FIXME should we update ctime ?
226			 * What is the following setxattr update the mode ?
227			 */
228			v9fs_vfs_setattr_dotl(&nop_mnt_idmap, dentry, &iattr);
229		}
230		break;
231	case ACL_TYPE_DEFAULT:
232		if (!S_ISDIR(inode->i_mode)) {
233			retval = acl ? -EINVAL : 0;
234			goto err_out;
235		}
236		break;
237	}
238
239	retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
240	if (!retval)
241		set_cached_acl(inode, type, acl);
242
243err_out:
244	kfree(value);
245	return retval;
246}
247
248static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl)
249{
250	int retval;
251	char *name;
252	size_t size;
253	void *buffer;
254
255	if (!acl)
256		return 0;
257
258	/* Set a setxattr request to server */
259	size = posix_acl_xattr_size(acl->a_count);
260	buffer = kmalloc(size, GFP_KERNEL);
261	if (!buffer)
262		return -ENOMEM;
263	retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
264	if (retval < 0)
265		goto err_free_out;
266	switch (type) {
267	case ACL_TYPE_ACCESS:
268		name = XATTR_NAME_POSIX_ACL_ACCESS;
269		break;
270	case ACL_TYPE_DEFAULT:
271		name = XATTR_NAME_POSIX_ACL_DEFAULT;
272		break;
273	default:
274		BUG();
275	}
276	retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0);
277err_free_out:
278	kfree(buffer);
279	return retval;
280}
281
282int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
283{
284	int retval = 0;
285	struct posix_acl *acl;
286
287	if (S_ISLNK(inode->i_mode))
288		return -EOPNOTSUPP;
289	acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
290	if (acl) {
291		retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
292		if (retval)
293			return retval;
294		set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
295		retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
296		posix_acl_release(acl);
297	}
298	return retval;
299}
300
301int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
302			struct posix_acl *dacl, struct posix_acl *acl)
303{
304	set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
305	set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
306	v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl);
307	v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
308	return 0;
309}
310
311void v9fs_put_acl(struct posix_acl *dacl,
312		  struct posix_acl *acl)
313{
314	posix_acl_release(dacl);
315	posix_acl_release(acl);
316}
317
318int v9fs_acl_mode(struct inode *dir, umode_t *modep,
319		  struct posix_acl **dpacl, struct posix_acl **pacl)
320{
321	int retval = 0;
322	umode_t mode = *modep;
323	struct posix_acl *acl = NULL;
324
325	if (!S_ISLNK(mode)) {
326		acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
327		if (IS_ERR(acl))
328			return PTR_ERR(acl);
329		if (!acl)
330			mode &= ~current_umask();
331	}
332	if (acl) {
333		if (S_ISDIR(mode))
334			*dpacl = posix_acl_dup(acl);
335		retval = __posix_acl_create(&acl, GFP_NOFS, &mode);
336		if (retval < 0)
337			return retval;
338		if (retval > 0)
339			*pacl = acl;
340		else
341			posix_acl_release(acl);
342	}
343	*modep  = mode;
344	return 0;
345}
346