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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 
__v9fs_get_acl(struct p9_fid * fid,char * name)27 static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
28 {
29 	ssize_t size;
30 	void *value = NULL;
31 	struct posix_acl *acl = NULL;
32 
33 	size = v9fs_fid_xattr_get(fid, name, NULL, 0);
34 	if (size > 0) {
35 		value = kzalloc(size, GFP_NOFS);
36 		if (!value)
37 			return ERR_PTR(-ENOMEM);
38 		size = v9fs_fid_xattr_get(fid, name, value, size);
39 		if (size > 0) {
40 			acl = posix_acl_from_xattr(value, size);
41 			if (IS_ERR(acl))
42 				goto err_out;
43 		}
44 	} else if (size == -ENODATA || size == 0 ||
45 		   size == -ENOSYS || size == -EOPNOTSUPP) {
46 		acl = NULL;
47 	} else
48 		acl = ERR_PTR(-EIO);
49 
50 err_out:
51 	kfree(value);
52 	return acl;
53 }
54 
v9fs_get_acl(struct inode * inode,struct p9_fid * fid)55 int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
56 {
57 	int retval = 0;
58 	struct posix_acl *pacl, *dacl;
59 	struct v9fs_session_info *v9ses;
60 
61 	v9ses = v9fs_inode2v9ses(inode);
62 	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
63 			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
64 		set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
65 		set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
66 		return 0;
67 	}
68 	/* get the default/access acl values and cache them */
69 	dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT);
70 	pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS);
71 
72 	if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
73 		set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
74 		set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
75 	} else
76 		retval = -EIO;
77 
78 	if (!IS_ERR(dacl))
79 		posix_acl_release(dacl);
80 
81 	if (!IS_ERR(pacl))
82 		posix_acl_release(pacl);
83 
84 	return retval;
85 }
86 
v9fs_get_cached_acl(struct inode * inode,int type)87 static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
88 {
89 	struct posix_acl *acl;
90 	/*
91 	 * 9p Always cache the acl value when
92 	 * instantiating the inode (v9fs_inode_from_fid)
93 	 */
94 	acl = get_cached_acl(inode, type);
95 	BUG_ON(acl == ACL_NOT_CACHED);
96 	return acl;
97 }
98 
v9fs_iop_get_acl(struct inode * inode,int type)99 struct posix_acl *v9fs_iop_get_acl(struct inode *inode, int type)
100 {
101 	struct v9fs_session_info *v9ses;
102 
103 	v9ses = v9fs_inode2v9ses(inode);
104 	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
105 			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
106 		/*
107 		 * On access = client  and acl = on mode get the acl
108 		 * values from the server
109 		 */
110 		return NULL;
111 	}
112 	return v9fs_get_cached_acl(inode, type);
113 
114 }
115 
v9fs_set_acl(struct dentry * dentry,int type,struct posix_acl * acl)116 static int v9fs_set_acl(struct dentry *dentry, int type, struct posix_acl *acl)
117 {
118 	int retval;
119 	char *name;
120 	size_t size;
121 	void *buffer;
122 	struct inode *inode = dentry->d_inode;
123 
124 	set_cached_acl(inode, type, acl);
125 
126 	if (!acl)
127 		return 0;
128 
129 	/* Set a setxattr request to server */
130 	size = posix_acl_xattr_size(acl->a_count);
131 	buffer = kmalloc(size, GFP_KERNEL);
132 	if (!buffer)
133 		return -ENOMEM;
134 	retval = posix_acl_to_xattr(acl, buffer, size);
135 	if (retval < 0)
136 		goto err_free_out;
137 	switch (type) {
138 	case ACL_TYPE_ACCESS:
139 		name = POSIX_ACL_XATTR_ACCESS;
140 		break;
141 	case ACL_TYPE_DEFAULT:
142 		name = POSIX_ACL_XATTR_DEFAULT;
143 		break;
144 	default:
145 		BUG();
146 	}
147 	retval = v9fs_xattr_set(dentry, name, buffer, size, 0);
148 err_free_out:
149 	kfree(buffer);
150 	return retval;
151 }
152 
v9fs_acl_chmod(struct dentry * dentry)153 int v9fs_acl_chmod(struct dentry *dentry)
154 {
155 	int retval = 0;
156 	struct posix_acl *acl;
157 	struct inode *inode = dentry->d_inode;
158 
159 	if (S_ISLNK(inode->i_mode))
160 		return -EOPNOTSUPP;
161 	acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
162 	if (acl) {
163 		retval = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
164 		if (retval)
165 			return retval;
166 		retval = v9fs_set_acl(dentry, ACL_TYPE_ACCESS, acl);
167 		posix_acl_release(acl);
168 	}
169 	return retval;
170 }
171 
v9fs_set_create_acl(struct dentry * dentry,struct posix_acl ** dpacl,struct posix_acl ** pacl)172 int v9fs_set_create_acl(struct dentry *dentry,
173 			struct posix_acl **dpacl, struct posix_acl **pacl)
174 {
175 	if (dentry) {
176 		v9fs_set_acl(dentry, ACL_TYPE_DEFAULT, *dpacl);
177 		v9fs_set_acl(dentry, ACL_TYPE_ACCESS, *pacl);
178 	}
179 	posix_acl_release(*dpacl);
180 	posix_acl_release(*pacl);
181 	*dpacl = *pacl = NULL;
182 	return 0;
183 }
184 
v9fs_acl_mode(struct inode * dir,umode_t * modep,struct posix_acl ** dpacl,struct posix_acl ** pacl)185 int v9fs_acl_mode(struct inode *dir, umode_t *modep,
186 		  struct posix_acl **dpacl, struct posix_acl **pacl)
187 {
188 	int retval = 0;
189 	umode_t mode = *modep;
190 	struct posix_acl *acl = NULL;
191 
192 	if (!S_ISLNK(mode)) {
193 		acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
194 		if (IS_ERR(acl))
195 			return PTR_ERR(acl);
196 		if (!acl)
197 			mode &= ~current_umask();
198 	}
199 	if (acl) {
200 		if (S_ISDIR(mode))
201 			*dpacl = posix_acl_dup(acl);
202 		retval = posix_acl_create(&acl, GFP_NOFS, &mode);
203 		if (retval < 0)
204 			return retval;
205 		if (retval > 0)
206 			*pacl = acl;
207 		else
208 			posix_acl_release(acl);
209 	}
210 	*modep  = mode;
211 	return 0;
212 }
213 
v9fs_remote_get_acl(struct dentry * dentry,const char * name,void * buffer,size_t size,int type)214 static int v9fs_remote_get_acl(struct dentry *dentry, const char *name,
215 			       void *buffer, size_t size, int type)
216 {
217 	char *full_name;
218 
219 	switch (type) {
220 	case ACL_TYPE_ACCESS:
221 		full_name =  POSIX_ACL_XATTR_ACCESS;
222 		break;
223 	case ACL_TYPE_DEFAULT:
224 		full_name = POSIX_ACL_XATTR_DEFAULT;
225 		break;
226 	default:
227 		BUG();
228 	}
229 	return v9fs_xattr_get(dentry, full_name, buffer, size);
230 }
231 
v9fs_xattr_get_acl(struct dentry * dentry,const char * name,void * buffer,size_t size,int type)232 static int v9fs_xattr_get_acl(struct dentry *dentry, const char *name,
233 			      void *buffer, size_t size, int type)
234 {
235 	struct v9fs_session_info *v9ses;
236 	struct posix_acl *acl;
237 	int error;
238 
239 	if (strcmp(name, "") != 0)
240 		return -EINVAL;
241 
242 	v9ses = v9fs_dentry2v9ses(dentry);
243 	/*
244 	 * We allow set/get/list of acl when access=client is not specified
245 	 */
246 	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
247 		return v9fs_remote_get_acl(dentry, name, buffer, size, type);
248 
249 	acl = v9fs_get_cached_acl(dentry->d_inode, type);
250 	if (IS_ERR(acl))
251 		return PTR_ERR(acl);
252 	if (acl == NULL)
253 		return -ENODATA;
254 	error = posix_acl_to_xattr(acl, buffer, size);
255 	posix_acl_release(acl);
256 
257 	return error;
258 }
259 
v9fs_remote_set_acl(struct dentry * dentry,const char * name,const void * value,size_t size,int flags,int type)260 static int v9fs_remote_set_acl(struct dentry *dentry, const char *name,
261 			      const void *value, size_t size,
262 			      int flags, int type)
263 {
264 	char *full_name;
265 
266 	switch (type) {
267 	case ACL_TYPE_ACCESS:
268 		full_name =  POSIX_ACL_XATTR_ACCESS;
269 		break;
270 	case ACL_TYPE_DEFAULT:
271 		full_name = POSIX_ACL_XATTR_DEFAULT;
272 		break;
273 	default:
274 		BUG();
275 	}
276 	return v9fs_xattr_set(dentry, full_name, value, size, flags);
277 }
278 
279 
v9fs_xattr_set_acl(struct dentry * dentry,const char * name,const void * value,size_t size,int flags,int type)280 static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
281 			      const void *value, size_t size,
282 			      int flags, int type)
283 {
284 	int retval;
285 	struct posix_acl *acl;
286 	struct v9fs_session_info *v9ses;
287 	struct inode *inode = dentry->d_inode;
288 
289 	if (strcmp(name, "") != 0)
290 		return -EINVAL;
291 
292 	v9ses = v9fs_dentry2v9ses(dentry);
293 	/*
294 	 * set the attribute on the remote. Without even looking at the
295 	 * xattr value. We leave it to the server to validate
296 	 */
297 	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
298 		return v9fs_remote_set_acl(dentry, name,
299 					   value, size, flags, type);
300 
301 	if (S_ISLNK(inode->i_mode))
302 		return -EOPNOTSUPP;
303 	if (!inode_owner_or_capable(inode))
304 		return -EPERM;
305 	if (value) {
306 		/* update the cached acl value */
307 		acl = posix_acl_from_xattr(value, size);
308 		if (IS_ERR(acl))
309 			return PTR_ERR(acl);
310 		else if (acl) {
311 			retval = posix_acl_valid(acl);
312 			if (retval)
313 				goto err_out;
314 		}
315 	} else
316 		acl = NULL;
317 
318 	switch (type) {
319 	case ACL_TYPE_ACCESS:
320 		name = POSIX_ACL_XATTR_ACCESS;
321 		if (acl) {
322 			umode_t mode = inode->i_mode;
323 			retval = posix_acl_equiv_mode(acl, &mode);
324 			if (retval < 0)
325 				goto err_out;
326 			else {
327 				struct iattr iattr;
328 				if (retval == 0) {
329 					/*
330 					 * ACL can be represented
331 					 * by the mode bits. So don't
332 					 * update ACL.
333 					 */
334 					acl = NULL;
335 					value = NULL;
336 					size = 0;
337 				}
338 				/* Updte the mode bits */
339 				iattr.ia_mode = ((mode & S_IALLUGO) |
340 						 (inode->i_mode & ~S_IALLUGO));
341 				iattr.ia_valid = ATTR_MODE;
342 				/* FIXME should we update ctime ?
343 				 * What is the following setxattr update the
344 				 * mode ?
345 				 */
346 				v9fs_vfs_setattr_dotl(dentry, &iattr);
347 			}
348 		}
349 		break;
350 	case ACL_TYPE_DEFAULT:
351 		name = POSIX_ACL_XATTR_DEFAULT;
352 		if (!S_ISDIR(inode->i_mode)) {
353 			retval = acl ? -EINVAL : 0;
354 			goto err_out;
355 		}
356 		break;
357 	default:
358 		BUG();
359 	}
360 	retval = v9fs_xattr_set(dentry, name, value, size, flags);
361 	if (!retval)
362 		set_cached_acl(inode, type, acl);
363 err_out:
364 	posix_acl_release(acl);
365 	return retval;
366 }
367 
368 const struct xattr_handler v9fs_xattr_acl_access_handler = {
369 	.prefix	= POSIX_ACL_XATTR_ACCESS,
370 	.flags	= ACL_TYPE_ACCESS,
371 	.get	= v9fs_xattr_get_acl,
372 	.set	= v9fs_xattr_set_acl,
373 };
374 
375 const struct xattr_handler v9fs_xattr_acl_default_handler = {
376 	.prefix	= POSIX_ACL_XATTR_DEFAULT,
377 	.flags	= ACL_TYPE_DEFAULT,
378 	.get	= v9fs_xattr_get_acl,
379 	.set	= v9fs_xattr_set_acl,
380 };
381