1 /*
2  * Copyright IBM Corporation, 2010
3  * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms of version 2.1 of the GNU Lesser General Public License
7  * as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it would be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
12  *
13  */
14 
15 #include <linux/module.h>
16 #include <linux/fs.h>
17 #include <net/9p/9p.h>
18 #include <net/9p/client.h>
19 #include <linux/slab.h>
20 #include <linux/sched.h>
21 #include <linux/posix_acl_xattr.h>
22 #include "xattr.h"
23 #include "acl.h"
24 #include "v9fs.h"
25 #include "v9fs_vfs.h"
26 #include "fid.h"
27 
__v9fs_get_acl(struct p9_fid * fid,char * name)28 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
29 {
30 	ssize_t size;
31 	void *value = NULL;
32 	struct posix_acl *acl = NULL;
33 
34 	size = v9fs_fid_xattr_get(fid, name, NULL, 0);
35 	if (size > 0) {
36 		value = kzalloc(size, GFP_NOFS);
37 		if (!value)
38 			return ERR_PTR(-ENOMEM);
39 		size = v9fs_fid_xattr_get(fid, name, value, size);
40 		if (size > 0) {
41 			acl = posix_acl_from_xattr(&init_user_ns, value, size);
42 			if (IS_ERR(acl))
43 				goto err_out;
44 		}
45 	} else if (size == -ENODATA || size == 0 ||
46 		   size == -ENOSYS || size == -EOPNOTSUPP) {
47 		acl = NULL;
48 	} else
49 		acl = ERR_PTR(-EIO);
50 
51 err_out:
52 	kfree(value);
53 	return acl;
54 }
55 
v9fs_get_acl(struct inode * inode,struct p9_fid * fid)56 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
57 {
58 	int retval = 0;
59 	struct posix_acl *pacl, *dacl;
60 	struct v9fs_session_info *v9ses;
61 
62 	v9ses = v9fs_inode2v9ses(inode);
63 	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
64 			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
65 		set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
66 		set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
67 		return 0;
68 	}
69 	/* get the default/access acl values and cache them */
70 	dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT);
71 	pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS);
72 
73 	if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
74 		set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
75 		set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
76 	} else
77 		retval = -EIO;
78 
79 	if (!IS_ERR(dacl))
80 		posix_acl_release(dacl);
81 
82 	if (!IS_ERR(pacl))
83 		posix_acl_release(pacl);
84 
85 	return retval;
86 }
87 
v9fs_get_cached_acl(struct inode * inode,int type)88 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
89 {
90 	struct posix_acl *acl;
91 	/*
92 	 * 9p Always cache the acl value when
93 	 * instantiating the inode (v9fs_inode_from_fid)
94 	 */
95 	acl = get_cached_acl(inode, type);
96 	BUG_ON(is_uncached_acl(acl));
97 	return acl;
98 }
99 
v9fs_iop_get_acl(struct inode * inode,int type)100 struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type)
101 {
102 	struct v9fs_session_info *v9ses;
103 
104 	v9ses = v9fs_inode2v9ses(inode);
105 	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
106 			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
107 		/*
108 		 * On access = client  and acl = on mode get the acl
109 		 * values from the server
110 		 */
111 		return NULL;
112 	}
113 	return v9fs_get_cached_acl(inode, type);
114 
115 }
116 
v9fs_set_acl(struct p9_fid * fid,int type,struct posix_acl * acl)117 static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl)
118 {
119 	int retval;
120 	char *name;
121 	size_t size;
122 	void *buffer;
123 	if (!acl)
124 		return 0;
125 
126 	/* Set a setxattr request to server */
127 	size = posix_acl_xattr_size(acl->a_count);
128 	buffer = kmalloc(size, GFP_KERNEL);
129 	if (!buffer)
130 		return -ENOMEM;
131 	retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
132 	if (retval < 0)
133 		goto err_free_out;
134 	switch (type) {
135 	case ACL_TYPE_ACCESS:
136 		name = XATTR_NAME_POSIX_ACL_ACCESS;
137 		break;
138 	case ACL_TYPE_DEFAULT:
139 		name = XATTR_NAME_POSIX_ACL_DEFAULT;
140 		break;
141 	default:
142 		BUG();
143 	}
144 	retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0);
145 err_free_out:
146 	kfree(buffer);
147 	return retval;
148 }
149 
v9fs_acl_chmod(struct inode * inode,struct p9_fid * fid)150 int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
151 {
152 	int retval = 0;
153 	struct posix_acl *acl;
154 
155 	if (S_ISLNK(inode->i_mode))
156 		return -EOPNOTSUPP;
157 	acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
158 	if (acl) {
159 		retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
160 		if (retval)
161 			return retval;
162 		set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
163 		retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
164 		posix_acl_release(acl);
165 	}
166 	return retval;
167 }
168 
v9fs_set_create_acl(struct inode * inode,struct p9_fid * fid,struct posix_acl * dacl,struct posix_acl * acl)169 int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
170 			struct posix_acl *dacl, struct posix_acl *acl)
171 {
172 	set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
173 	set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
174 	v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl);
175 	v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
176 	return 0;
177 }
178 
v9fs_put_acl(struct posix_acl * dacl,struct posix_acl * acl)179 void v9fs_put_acl(struct posix_acl *dacl,
180 		  struct posix_acl *acl)
181 {
182 	posix_acl_release(dacl);
183 	posix_acl_release(acl);
184 }
185 
v9fs_acl_mode(struct inode * dir,umode_t * modep,struct posix_acl ** dpacl,struct posix_acl ** pacl)186 int v9fs_acl_mode(struct inode *dir, umode_t *modep,
187 		  struct posix_acl **dpacl, struct posix_acl **pacl)
188 {
189 	int retval = 0;
190 	umode_t mode = *modep;
191 	struct posix_acl *acl = NULL;
192 
193 	if (!S_ISLNK(mode)) {
194 		acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
195 		if (IS_ERR(acl))
196 			return PTR_ERR(acl);
197 		if (!acl)
198 			mode &= ~current_umask();
199 	}
200 	if (acl) {
201 		if (S_ISDIR(mode))
202 			*dpacl = posix_acl_dup(acl);
203 		retval = __posix_acl_create(&acl, GFP_NOFS, &mode);
204 		if (retval < 0)
205 			return retval;
206 		if (retval > 0)
207 			*pacl = acl;
208 		else
209 			posix_acl_release(acl);
210 	}
211 	*modep  = mode;
212 	return 0;
213 }
214 
v9fs_xattr_get_acl(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,void * buffer,size_t size)215 static int v9fs_xattr_get_acl(const struct xattr_handler *handler,
216 			      struct dentry *dentry, struct inode *inode,
217 			      const char *name, void *buffer, size_t size)
218 {
219 	struct v9fs_session_info *v9ses;
220 	struct posix_acl *acl;
221 	int error;
222 
223 	v9ses = v9fs_dentry2v9ses(dentry);
224 	/*
225 	 * We allow set/get/list of acl when access=client is not specified
226 	 */
227 	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
228 		return v9fs_xattr_get(dentry, handler->name, buffer, size);
229 
230 	acl = v9fs_get_cached_acl(inode, handler->flags);
231 	if (IS_ERR(acl))
232 		return PTR_ERR(acl);
233 	if (acl == NULL)
234 		return -ENODATA;
235 	error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
236 	posix_acl_release(acl);
237 
238 	return error;
239 }
240 
v9fs_xattr_set_acl(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,const void * value,size_t size,int flags)241 static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
242 			      struct dentry *dentry, struct inode *inode,
243 			      const char *name, const void *value,
244 			      size_t size, int flags)
245 {
246 	int retval;
247 	struct posix_acl *acl;
248 	struct v9fs_session_info *v9ses;
249 
250 	v9ses = v9fs_dentry2v9ses(dentry);
251 	/*
252 	 * set the attribute on the remote. Without even looking at the
253 	 * xattr value. We leave it to the server to validate
254 	 */
255 	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
256 		return v9fs_xattr_set(dentry, handler->name, value, size,
257 				      flags);
258 
259 	if (S_ISLNK(inode->i_mode))
260 		return -EOPNOTSUPP;
261 	if (!inode_owner_or_capable(inode))
262 		return -EPERM;
263 	if (value) {
264 		/* update the cached acl value */
265 		acl = posix_acl_from_xattr(&init_user_ns, value, size);
266 		if (IS_ERR(acl))
267 			return PTR_ERR(acl);
268 		else if (acl) {
269 			retval = posix_acl_valid(inode->i_sb->s_user_ns, acl);
270 			if (retval)
271 				goto err_out;
272 		}
273 	} else
274 		acl = NULL;
275 
276 	switch (handler->flags) {
277 	case ACL_TYPE_ACCESS:
278 		if (acl) {
279 			struct iattr iattr = { 0 };
280 			struct posix_acl *old_acl = acl;
281 
282 			retval = posix_acl_update_mode(inode, &iattr.ia_mode, &acl);
283 			if (retval)
284 				goto err_out;
285 			if (!acl) {
286 				/*
287 				 * ACL can be represented
288 				 * by the mode bits. So don't
289 				 * update ACL.
290 				 */
291 				posix_acl_release(old_acl);
292 				value = NULL;
293 				size = 0;
294 			}
295 			iattr.ia_valid = ATTR_MODE;
296 			/* FIXME should we update ctime ?
297 			 * What is the following setxattr update the
298 			 * mode ?
299 			 */
300 			v9fs_vfs_setattr_dotl(dentry, &iattr);
301 		}
302 		break;
303 	case ACL_TYPE_DEFAULT:
304 		if (!S_ISDIR(inode->i_mode)) {
305 			retval = acl ? -EINVAL : 0;
306 			goto err_out;
307 		}
308 		break;
309 	default:
310 		BUG();
311 	}
312 	retval = v9fs_xattr_set(dentry, handler->name, value, size, flags);
313 	if (!retval)
314 		set_cached_acl(inode, handler->flags, acl);
315 err_out:
316 	posix_acl_release(acl);
317 	return retval;
318 }
319 
320 const struct xattr_handler v9fs_xattr_acl_access_handler = {
321 	.name	= XATTR_NAME_POSIX_ACL_ACCESS,
322 	.flags	= ACL_TYPE_ACCESS,
323 	.get	= v9fs_xattr_get_acl,
324 	.set	= v9fs_xattr_set_acl,
325 };
326 
327 const struct xattr_handler v9fs_xattr_acl_default_handler = {
328 	.name	= XATTR_NAME_POSIX_ACL_DEFAULT,
329 	.flags	= ACL_TYPE_DEFAULT,
330 	.get	= v9fs_xattr_get_acl,
331 	.set	= v9fs_xattr_set_acl,
332 };
333