xref: /openbmc/linux/fs/nfsd/nfs4recover.c (revision a1e58bbd) 
1 /*
2 *  linux/fs/nfsd/nfs4recover.c
3 *
4 *  Copyright (c) 2004 The Regents of the University of Michigan.
5 *  All rights reserved.
6 *
7 *  Andy Adamson <andros@citi.umich.edu>
8 *
9 *  Redistribution and use in source and binary forms, with or without
10 *  modification, are permitted provided that the following conditions
11 *  are met:
12 *
13 *  1. Redistributions of source code must retain the above copyright
14 *     notice, this list of conditions and the following disclaimer.
15 *  2. Redistributions in binary form must reproduce the above copyright
16 *     notice, this list of conditions and the following disclaimer in the
17 *     documentation and/or other materials provided with the distribution.
18 *  3. Neither the name of the University nor the names of its
19 *     contributors may be used to endorse or promote products derived
20 *     from this software without specific prior written permission.
21 *
22 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
23 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
25 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
29 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
30 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
31 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
32 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 *
34 */
35 
36 #include <linux/err.h>
37 #include <linux/sunrpc/svc.h>
38 #include <linux/nfsd/nfsd.h>
39 #include <linux/nfs4.h>
40 #include <linux/nfsd/state.h>
41 #include <linux/nfsd/xdr4.h>
42 #include <linux/param.h>
43 #include <linux/file.h>
44 #include <linux/namei.h>
45 #include <asm/uaccess.h>
46 #include <linux/scatterlist.h>
47 #include <linux/crypto.h>
48 #include <linux/sched.h>
49 
50 #define NFSDDBG_FACILITY                NFSDDBG_PROC
51 
52 /* Globals */
53 static struct nameidata rec_dir;
54 static int rec_dir_init = 0;
55 
56 static void
57 nfs4_save_user(uid_t *saveuid, gid_t *savegid)
58 {
59 	*saveuid = current->fsuid;
60 	*savegid = current->fsgid;
61 	current->fsuid = 0;
62 	current->fsgid = 0;
63 }
64 
65 static void
66 nfs4_reset_user(uid_t saveuid, gid_t savegid)
67 {
68 	current->fsuid = saveuid;
69 	current->fsgid = savegid;
70 }
71 
72 static void
73 md5_to_hex(char *out, char *md5)
74 {
75 	int i;
76 
77 	for (i=0; i<16; i++) {
78 		unsigned char c = md5[i];
79 
80 		*out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
81 		*out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
82 	}
83 	*out = '\0';
84 }
85 
86 __be32
87 nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
88 {
89 	struct xdr_netobj cksum;
90 	struct hash_desc desc;
91 	struct scatterlist sg;
92 	__be32 status = nfserr_resource;
93 
94 	dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
95 			clname->len, clname->data);
96 	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
97 	desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
98 	if (IS_ERR(desc.tfm))
99 		goto out_no_tfm;
100 	cksum.len = crypto_hash_digestsize(desc.tfm);
101 	cksum.data = kmalloc(cksum.len, GFP_KERNEL);
102 	if (cksum.data == NULL)
103  		goto out;
104 
105 	sg_init_one(&sg, clname->data, clname->len);
106 
107 	if (crypto_hash_digest(&desc, &sg, sg.length, cksum.data))
108 		goto out;
109 
110 	md5_to_hex(dname, cksum.data);
111 
112 	kfree(cksum.data);
113 	status = nfs_ok;
114 out:
115 	crypto_free_hash(desc.tfm);
116 out_no_tfm:
117 	return status;
118 }
119 
120 static void
121 nfsd4_sync_rec_dir(void)
122 {
123 	mutex_lock(&rec_dir.path.dentry->d_inode->i_mutex);
124 	nfsd_sync_dir(rec_dir.path.dentry);
125 	mutex_unlock(&rec_dir.path.dentry->d_inode->i_mutex);
126 }
127 
128 int
129 nfsd4_create_clid_dir(struct nfs4_client *clp)
130 {
131 	char *dname = clp->cl_recdir;
132 	struct dentry *dentry;
133 	uid_t uid;
134 	gid_t gid;
135 	int status;
136 
137 	dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
138 
139 	if (!rec_dir_init || clp->cl_firststate)
140 		return 0;
141 
142 	nfs4_save_user(&uid, &gid);
143 
144 	/* lock the parent */
145 	mutex_lock(&rec_dir.path.dentry->d_inode->i_mutex);
146 
147 	dentry = lookup_one_len(dname, rec_dir.path.dentry, HEXDIR_LEN-1);
148 	if (IS_ERR(dentry)) {
149 		status = PTR_ERR(dentry);
150 		goto out_unlock;
151 	}
152 	status = -EEXIST;
153 	if (dentry->d_inode) {
154 		dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
155 		goto out_put;
156 	}
157 	status = vfs_mkdir(rec_dir.path.dentry->d_inode, dentry, S_IRWXU);
158 out_put:
159 	dput(dentry);
160 out_unlock:
161 	mutex_unlock(&rec_dir.path.dentry->d_inode->i_mutex);
162 	if (status == 0) {
163 		clp->cl_firststate = 1;
164 		nfsd4_sync_rec_dir();
165 	}
166 	nfs4_reset_user(uid, gid);
167 	dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
168 	return status;
169 }
170 
171 typedef int (recdir_func)(struct dentry *, struct dentry *);
172 
173 struct dentry_list {
174 	struct dentry *dentry;
175 	struct list_head list;
176 };
177 
178 struct dentry_list_arg {
179 	struct list_head dentries;
180 	struct dentry *parent;
181 };
182 
183 static int
184 nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
185 		loff_t offset, u64 ino, unsigned int d_type)
186 {
187 	struct dentry_list_arg *dla = arg;
188 	struct list_head *dentries = &dla->dentries;
189 	struct dentry *parent = dla->parent;
190 	struct dentry *dentry;
191 	struct dentry_list *child;
192 
193 	if (name && isdotent(name, namlen))
194 		return 0;
195 	dentry = lookup_one_len(name, parent, namlen);
196 	if (IS_ERR(dentry))
197 		return PTR_ERR(dentry);
198 	child = kmalloc(sizeof(*child), GFP_KERNEL);
199 	if (child == NULL)
200 		return -ENOMEM;
201 	child->dentry = dentry;
202 	list_add(&child->list, dentries);
203 	return 0;
204 }
205 
206 static int
207 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
208 {
209 	struct file *filp;
210 	struct dentry_list_arg dla = {
211 		.parent = dir,
212 	};
213 	struct list_head *dentries = &dla.dentries;
214 	struct dentry_list *child;
215 	uid_t uid;
216 	gid_t gid;
217 	int status;
218 
219 	if (!rec_dir_init)
220 		return 0;
221 
222 	nfs4_save_user(&uid, &gid);
223 
224 	filp = dentry_open(dget(dir), mntget(rec_dir.path.mnt), O_RDONLY);
225 	status = PTR_ERR(filp);
226 	if (IS_ERR(filp))
227 		goto out;
228 	INIT_LIST_HEAD(dentries);
229 	status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
230 	fput(filp);
231 	while (!list_empty(dentries)) {
232 		child = list_entry(dentries->next, struct dentry_list, list);
233 		status = f(dir, child->dentry);
234 		if (status)
235 			goto out;
236 		list_del(&child->list);
237 		dput(child->dentry);
238 		kfree(child);
239 	}
240 out:
241 	while (!list_empty(dentries)) {
242 		child = list_entry(dentries->next, struct dentry_list, list);
243 		list_del(&child->list);
244 		dput(child->dentry);
245 		kfree(child);
246 	}
247 	nfs4_reset_user(uid, gid);
248 	return status;
249 }
250 
251 static int
252 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
253 {
254 	int status;
255 
256 	if (!S_ISREG(dir->d_inode->i_mode)) {
257 		printk("nfsd4: non-file found in client recovery directory\n");
258 		return -EINVAL;
259 	}
260 	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
261 	status = vfs_unlink(dir->d_inode, dentry);
262 	mutex_unlock(&dir->d_inode->i_mutex);
263 	return status;
264 }
265 
266 static int
267 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
268 {
269 	int status;
270 
271 	/* For now this directory should already be empty, but we empty it of
272 	 * any regular files anyway, just in case the directory was created by
273 	 * a kernel from the future.... */
274 	nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
275 	mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
276 	status = vfs_rmdir(dir->d_inode, dentry);
277 	mutex_unlock(&dir->d_inode->i_mutex);
278 	return status;
279 }
280 
281 static int
282 nfsd4_unlink_clid_dir(char *name, int namlen)
283 {
284 	struct dentry *dentry;
285 	int status;
286 
287 	dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
288 
289 	mutex_lock(&rec_dir.path.dentry->d_inode->i_mutex);
290 	dentry = lookup_one_len(name, rec_dir.path.dentry, namlen);
291 	mutex_unlock(&rec_dir.path.dentry->d_inode->i_mutex);
292 	if (IS_ERR(dentry)) {
293 		status = PTR_ERR(dentry);
294 		return status;
295 	}
296 	status = -ENOENT;
297 	if (!dentry->d_inode)
298 		goto out;
299 
300 	status = nfsd4_clear_clid_dir(rec_dir.path.dentry, dentry);
301 out:
302 	dput(dentry);
303 	return status;
304 }
305 
306 void
307 nfsd4_remove_clid_dir(struct nfs4_client *clp)
308 {
309 	uid_t uid;
310 	gid_t gid;
311 	int status;
312 
313 	if (!rec_dir_init || !clp->cl_firststate)
314 		return;
315 
316 	clp->cl_firststate = 0;
317 	nfs4_save_user(&uid, &gid);
318 	status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
319 	nfs4_reset_user(uid, gid);
320 	if (status == 0)
321 		nfsd4_sync_rec_dir();
322 	if (status)
323 		printk("NFSD: Failed to remove expired client state directory"
324 				" %.*s\n", HEXDIR_LEN, clp->cl_recdir);
325 	return;
326 }
327 
328 static int
329 purge_old(struct dentry *parent, struct dentry *child)
330 {
331 	int status;
332 
333 	if (nfs4_has_reclaimed_state(child->d_name.name))
334 		return 0;
335 
336 	status = nfsd4_clear_clid_dir(parent, child);
337 	if (status)
338 		printk("failed to remove client recovery directory %s\n",
339 				child->d_name.name);
340 	/* Keep trying, success or failure: */
341 	return 0;
342 }
343 
344 void
345 nfsd4_recdir_purge_old(void) {
346 	int status;
347 
348 	if (!rec_dir_init)
349 		return;
350 	status = nfsd4_list_rec_dir(rec_dir.path.dentry, purge_old);
351 	if (status == 0)
352 		nfsd4_sync_rec_dir();
353 	if (status)
354 		printk("nfsd4: failed to purge old clients from recovery"
355 			" directory %s\n", rec_dir.path.dentry->d_name.name);
356 	return;
357 }
358 
359 static int
360 load_recdir(struct dentry *parent, struct dentry *child)
361 {
362 	if (child->d_name.len != HEXDIR_LEN - 1) {
363 		printk("nfsd4: illegal name %s in recovery directory\n",
364 				child->d_name.name);
365 		/* Keep trying; maybe the others are OK: */
366 		return 0;
367 	}
368 	nfs4_client_to_reclaim(child->d_name.name);
369 	return 0;
370 }
371 
372 int
373 nfsd4_recdir_load(void) {
374 	int status;
375 
376 	status = nfsd4_list_rec_dir(rec_dir.path.dentry, load_recdir);
377 	if (status)
378 		printk("nfsd4: failed loading clients from recovery"
379 			" directory %s\n", rec_dir.path.dentry->d_name.name);
380 	return status;
381 }
382 
383 /*
384  * Hold reference to the recovery directory.
385  */
386 
387 void
388 nfsd4_init_recdir(char *rec_dirname)
389 {
390 	uid_t			uid = 0;
391 	gid_t			gid = 0;
392 	int 			status;
393 
394 	printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
395 			rec_dirname);
396 
397 	BUG_ON(rec_dir_init);
398 
399 	nfs4_save_user(&uid, &gid);
400 
401 	status = path_lookup(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
402 			&rec_dir);
403 	if (status)
404 		printk("NFSD: unable to find recovery directory %s\n",
405 				rec_dirname);
406 
407 	if (!status)
408 		rec_dir_init = 1;
409 	nfs4_reset_user(uid, gid);
410 }
411 
412 void
413 nfsd4_shutdown_recdir(void)
414 {
415 	if (!rec_dir_init)
416 		return;
417 	rec_dir_init = 0;
418 	path_put(&rec_dir.path);
419 }
420