xref: /linux/fs/nfsd/nfs4recover.c (revision 20d0021394c1b070bf04b22c5bc8fdb437edd4c5) 
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 
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 <asm/scatterlist.h>
47 #include <linux/crypto.h>
48 
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 int
87 nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
88 {
89 	struct xdr_netobj cksum;
90 	struct crypto_tfm *tfm;
91 	struct scatterlist sg[1];
92 	int status = nfserr_resource;
93 
94 	dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
95 			clname->len, clname->data);
96 	tfm = crypto_alloc_tfm("md5", 0);
97 	if (tfm == NULL)
98 		goto out;
99 	cksum.len = crypto_tfm_alg_digestsize(tfm);
100 	cksum.data = kmalloc(cksum.len, GFP_KERNEL);
101 	if (cksum.data == NULL)
102  		goto out;
103 	crypto_digest_init(tfm);
104 
105 	sg[0].page = virt_to_page(clname->data);
106 	sg[0].offset = offset_in_page(clname->data);
107 	sg[0].length = clname->len;
108 
109 	crypto_digest_update(tfm, sg, 1);
110 	crypto_digest_final(tfm, cksum.data);
111 
112 	md5_to_hex(dname, cksum.data);
113 
114 	kfree(cksum.data);
115 	status = nfs_ok;
116 out:
117 	if (tfm)
118 		crypto_free_tfm(tfm);
119 	return status;
120 }
121 
122 static void
123 nfsd4_sync_rec_dir(void)
124 {
125 	down(&rec_dir.dentry->d_inode->i_sem);
126 	nfsd_sync_dir(rec_dir.dentry);
127 	up(&rec_dir.dentry->d_inode->i_sem);
128 }
129 
130 int
131 nfsd4_create_clid_dir(struct nfs4_client *clp)
132 {
133 	char *dname = clp->cl_recdir;
134 	struct dentry *dentry;
135 	uid_t uid;
136 	gid_t gid;
137 	int status;
138 
139 	dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
140 
141 	if (!rec_dir_init || clp->cl_firststate)
142 		return 0;
143 
144 	nfs4_save_user(&uid, &gid);
145 
146 	/* lock the parent */
147 	down(&rec_dir.dentry->d_inode->i_sem);
148 
149 	dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
150 	if (IS_ERR(dentry)) {
151 		status = PTR_ERR(dentry);
152 		goto out_unlock;
153 	}
154 	status = -EEXIST;
155 	if (dentry->d_inode) {
156 		dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
157 		goto out_put;
158 	}
159 	status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
160 out_put:
161 	dput(dentry);
162 out_unlock:
163 	up(&rec_dir.dentry->d_inode->i_sem);
164 	if (status == 0) {
165 		clp->cl_firststate = 1;
166 		nfsd4_sync_rec_dir();
167 	}
168 	nfs4_reset_user(uid, gid);
169 	dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
170 	return status;
171 }
172 
173 typedef int (recdir_func)(struct dentry *, struct dentry *);
174 
175 struct dentry_list {
176 	struct dentry *dentry;
177 	struct list_head list;
178 };
179 
180 struct dentry_list_arg {
181 	struct list_head dentries;
182 	struct dentry *parent;
183 };
184 
185 static int
186 nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
187 		loff_t offset, ino_t ino, unsigned int d_type)
188 {
189 	struct dentry_list_arg *dla = arg;
190 	struct list_head *dentries = &dla->dentries;
191 	struct dentry *parent = dla->parent;
192 	struct dentry *dentry;
193 	struct dentry_list *child;
194 
195 	if (name && isdotent(name, namlen))
196 		return nfs_ok;
197 	dentry = lookup_one_len(name, parent, namlen);
198 	if (IS_ERR(dentry))
199 		return PTR_ERR(dentry);
200 	child = kmalloc(sizeof(*child), GFP_KERNEL);
201 	if (child == NULL)
202 		return -ENOMEM;
203 	child->dentry = dentry;
204 	list_add(&child->list, dentries);
205 	return 0;
206 }
207 
208 static int
209 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
210 {
211 	struct file *filp;
212 	struct dentry_list_arg dla = {
213 		.parent = dir,
214 	};
215 	struct list_head *dentries = &dla.dentries;
216 	struct dentry_list *child;
217 	uid_t uid;
218 	gid_t gid;
219 	int status;
220 
221 	if (!rec_dir_init)
222 		return 0;
223 
224 	nfs4_save_user(&uid, &gid);
225 
226 	filp = dentry_open(dget(dir), mntget(rec_dir.mnt),
227 			O_RDWR);
228 	status = PTR_ERR(filp);
229 	if (IS_ERR(filp))
230 		goto out;
231 	INIT_LIST_HEAD(dentries);
232 	status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
233 	fput(filp);
234 	while (!list_empty(dentries)) {
235 		child = list_entry(dentries->next, struct dentry_list, list);
236 		status = f(dir, child->dentry);
237 		if (status)
238 			goto out;
239 		list_del(&child->list);
240 		dput(child->dentry);
241 		kfree(child);
242 	}
243 out:
244 	while (!list_empty(dentries)) {
245 		child = list_entry(dentries->next, struct dentry_list, list);
246 		list_del(&child->list);
247 		dput(child->dentry);
248 		kfree(child);
249 	}
250 	nfs4_reset_user(uid, gid);
251 	return status;
252 }
253 
254 static int
255 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
256 {
257 	int status;
258 
259 	if (!S_ISREG(dir->d_inode->i_mode)) {
260 		printk("nfsd4: non-file found in client recovery directory\n");
261 		return -EINVAL;
262 	}
263 	down(&dir->d_inode->i_sem);
264 	status = vfs_unlink(dir->d_inode, dentry);
265 	up(&dir->d_inode->i_sem);
266 	return status;
267 }
268 
269 static int
270 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
271 {
272 	int status;
273 
274 	/* For now this directory should already be empty, but we empty it of
275 	 * any regular files anyway, just in case the directory was created by
276 	 * a kernel from the future.... */
277 	nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
278 	down(&dir->d_inode->i_sem);
279 	status = vfs_rmdir(dir->d_inode, dentry);
280 	up(&dir->d_inode->i_sem);
281 	return status;
282 }
283 
284 static int
285 nfsd4_unlink_clid_dir(char *name, int namlen)
286 {
287 	struct dentry *dentry;
288 	int status;
289 
290 	dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
291 
292 	down(&rec_dir.dentry->d_inode->i_sem);
293 	dentry = lookup_one_len(name, rec_dir.dentry, namlen);
294 	up(&rec_dir.dentry->d_inode->i_sem);
295 	if (IS_ERR(dentry)) {
296 		status = PTR_ERR(dentry);
297 		return status;
298 	}
299 	status = -ENOENT;
300 	if (!dentry->d_inode)
301 		goto out;
302 
303 	status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry);
304 out:
305 	dput(dentry);
306 	return status;
307 }
308 
309 void
310 nfsd4_remove_clid_dir(struct nfs4_client *clp)
311 {
312 	uid_t uid;
313 	gid_t gid;
314 	int status;
315 
316 	if (!rec_dir_init || !clp->cl_firststate)
317 		return;
318 
319 	clp->cl_firststate = 0;
320 	nfs4_save_user(&uid, &gid);
321 	status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
322 	nfs4_reset_user(uid, gid);
323 	if (status == 0)
324 		nfsd4_sync_rec_dir();
325 	if (status)
326 		printk("NFSD: Failed to remove expired client state directory"
327 				" %.*s\n", HEXDIR_LEN, clp->cl_recdir);
328 	return;
329 }
330 
331 static int
332 purge_old(struct dentry *parent, struct dentry *child)
333 {
334 	int status;
335 
336 	if (nfs4_has_reclaimed_state(child->d_name.name))
337 		return nfs_ok;
338 
339 	status = nfsd4_clear_clid_dir(parent, child);
340 	if (status)
341 		printk("failed to remove client recovery directory %s\n",
342 				child->d_name.name);
343 	/* Keep trying, success or failure: */
344 	return nfs_ok;
345 }
346 
347 void
348 nfsd4_recdir_purge_old(void) {
349 	int status;
350 
351 	if (!rec_dir_init)
352 		return;
353 	status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
354 	if (status == 0)
355 		nfsd4_sync_rec_dir();
356 	if (status)
357 		printk("nfsd4: failed to purge old clients from recovery"
358 			" directory %s\n", rec_dir.dentry->d_name.name);
359 	return;
360 }
361 
362 static int
363 load_recdir(struct dentry *parent, struct dentry *child)
364 {
365 	if (child->d_name.len != HEXDIR_LEN - 1) {
366 		printk("nfsd4: illegal name %s in recovery directory\n",
367 				child->d_name.name);
368 		/* Keep trying; maybe the others are OK: */
369 		return nfs_ok;
370 	}
371 	nfs4_client_to_reclaim(child->d_name.name);
372 	return nfs_ok;
373 }
374 
375 int
376 nfsd4_recdir_load(void) {
377 	int status;
378 
379 	status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
380 	if (status)
381 		printk("nfsd4: failed loading clients from recovery"
382 			" directory %s\n", rec_dir.dentry->d_name.name);
383 	return status;
384 }
385 
386 /*
387  * Hold reference to the recovery directory.
388  */
389 
390 void
391 nfsd4_init_recdir(char *rec_dirname)
392 {
393 	uid_t			uid = 0;
394 	gid_t			gid = 0;
395 	int 			status;
396 
397 	printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
398 			rec_dirname);
399 
400 	BUG_ON(rec_dir_init);
401 
402 	nfs4_save_user(&uid, &gid);
403 
404 	status = path_lookup(rec_dirname, LOOKUP_FOLLOW, &rec_dir);
405 	if (status == -ENOENT)
406 		printk("NFSD: recovery directory %s doesn't exist\n",
407 				rec_dirname);
408 
409 	if (!status)
410 		rec_dir_init = 1;
411 	nfs4_reset_user(uid, gid);
412 }
413 
414 void
415 nfsd4_shutdown_recdir(void)
416 {
417 	if (!rec_dir_init)
418 		return;
419 	rec_dir_init = 0;
420 	path_release(&rec_dir);
421 }
422