xref: /linux/fs/nfsd/nfs4recover.c (revision d67b569f5f620c0fb95d5212642746b7ba9d29e4) 
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 int
123 nfsd4_rec_fsync(struct dentry *dentry)
124 {
125 	struct file *filp;
126 	int status = nfs_ok;
127 
128 	dprintk("NFSD: nfs4_fsync_rec_dir\n");
129 	filp = dentry_open(dget(dentry), mntget(rec_dir.mnt), O_RDWR);
130 	if (IS_ERR(filp)) {
131 		status = PTR_ERR(filp);
132 		goto out;
133 	}
134 	if (filp->f_op && filp->f_op->fsync)
135 		status = filp->f_op->fsync(filp, filp->f_dentry, 0);
136 	fput(filp);
137 out:
138 	if (status)
139 		printk("nfsd4: unable to sync recovery directory\n");
140 	return status;
141 }
142 
143 int
144 nfsd4_create_clid_dir(struct nfs4_client *clp)
145 {
146 	char *dname = clp->cl_recdir;
147 	struct dentry *dentry;
148 	uid_t uid;
149 	gid_t gid;
150 	int status;
151 
152 	dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
153 
154 	if (!rec_dir_init || clp->cl_firststate)
155 		return 0;
156 
157 	nfs4_save_user(&uid, &gid);
158 
159 	/* lock the parent */
160 	down(&rec_dir.dentry->d_inode->i_sem);
161 
162 	dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
163 	if (IS_ERR(dentry)) {
164 		status = PTR_ERR(dentry);
165 		goto out_unlock;
166 	}
167 	status = -EEXIST;
168 	if (dentry->d_inode) {
169 		dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
170 		goto out_put;
171 	}
172 	status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
173 out_put:
174 	dput(dentry);
175 out_unlock:
176 	up(&rec_dir.dentry->d_inode->i_sem);
177 	if (status == 0) {
178 		clp->cl_firststate = 1;
179 		status = nfsd4_rec_fsync(rec_dir.dentry);
180 	}
181 	nfs4_reset_user(uid, gid);
182 	dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
183 	return status;
184 }
185 
186 typedef int (recdir_func)(struct dentry *, struct dentry *);
187 
188 struct dentry_list {
189 	struct dentry *dentry;
190 	struct list_head list;
191 };
192 
193 struct dentry_list_arg {
194 	struct list_head dentries;
195 	struct dentry *parent;
196 };
197 
198 static int
199 nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
200 		loff_t offset, ino_t ino, unsigned int d_type)
201 {
202 	struct dentry_list_arg *dla = arg;
203 	struct list_head *dentries = &dla->dentries;
204 	struct dentry *parent = dla->parent;
205 	struct dentry *dentry;
206 	struct dentry_list *child;
207 
208 	if (name && isdotent(name, namlen))
209 		return nfs_ok;
210 	dentry = lookup_one_len(name, parent, namlen);
211 	if (IS_ERR(dentry))
212 		return PTR_ERR(dentry);
213 	child = kmalloc(sizeof(*child), GFP_KERNEL);
214 	if (child == NULL)
215 		return -ENOMEM;
216 	child->dentry = dentry;
217 	list_add(&child->list, dentries);
218 	return 0;
219 }
220 
221 static int
222 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
223 {
224 	struct file *filp;
225 	struct dentry_list_arg dla = {
226 		.parent = dir,
227 	};
228 	struct list_head *dentries = &dla.dentries;
229 	struct dentry_list *child;
230 	uid_t uid;
231 	gid_t gid;
232 	int status;
233 
234 	if (!rec_dir_init)
235 		return 0;
236 
237 	nfs4_save_user(&uid, &gid);
238 
239 	filp = dentry_open(dget(dir), mntget(rec_dir.mnt),
240 			O_RDWR);
241 	status = PTR_ERR(filp);
242 	if (IS_ERR(filp))
243 		goto out;
244 	INIT_LIST_HEAD(dentries);
245 	status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
246 	fput(filp);
247 	while (!list_empty(dentries)) {
248 		child = list_entry(dentries->next, struct dentry_list, list);
249 		status = f(dir, child->dentry);
250 		if (status)
251 			goto out;
252 		list_del(&child->list);
253 		dput(child->dentry);
254 		kfree(child);
255 	}
256 out:
257 	while (!list_empty(dentries)) {
258 		child = list_entry(dentries->next, struct dentry_list, list);
259 		list_del(&child->list);
260 		dput(child->dentry);
261 		kfree(child);
262 	}
263 	nfs4_reset_user(uid, gid);
264 	return status;
265 }
266 
267 static int
268 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
269 {
270 	int status;
271 
272 	if (!S_ISREG(dir->d_inode->i_mode)) {
273 		printk("nfsd4: non-file found in client recovery directory\n");
274 		return -EINVAL;
275 	}
276 	down(&dir->d_inode->i_sem);
277 	status = vfs_unlink(dir->d_inode, dentry);
278 	up(&dir->d_inode->i_sem);
279 	return status;
280 }
281 
282 static int
283 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
284 {
285 	int status;
286 
287 	/* For now this directory should already be empty, but we empty it of
288 	 * any regular files anyway, just in case the directory was created by
289 	 * a kernel from the future.... */
290 	nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
291 	down(&dir->d_inode->i_sem);
292 	status = vfs_rmdir(dir->d_inode, dentry);
293 	up(&dir->d_inode->i_sem);
294 	return status;
295 }
296 
297 static int
298 nfsd4_unlink_clid_dir(char *name, int namlen)
299 {
300 	struct dentry *dentry;
301 	int status;
302 
303 	dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
304 
305 	dentry = lookup_one_len(name, rec_dir.dentry, namlen);
306 	if (IS_ERR(dentry)) {
307 		status = PTR_ERR(dentry);
308 		return status;
309 	}
310 	status = -ENOENT;
311 	if (!dentry->d_inode)
312 		goto out;
313 
314 	status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry);
315 out:
316 	dput(dentry);
317 	return status;
318 }
319 
320 void
321 nfsd4_remove_clid_dir(struct nfs4_client *clp)
322 {
323 	uid_t uid;
324 	gid_t gid;
325 	int status;
326 
327 	if (!rec_dir_init || !clp->cl_firststate)
328 		return;
329 
330 	nfs4_save_user(&uid, &gid);
331 	status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
332 	nfs4_reset_user(uid, gid);
333 	if (status == 0)
334 		status = nfsd4_rec_fsync(rec_dir.dentry);
335 	if (status)
336 		printk("NFSD: Failed to remove expired client state directory"
337 				" %.*s\n", HEXDIR_LEN, clp->cl_recdir);
338 	return;
339 }
340 
341 static int
342 purge_old(struct dentry *parent, struct dentry *child)
343 {
344 	int status;
345 
346 	if (nfs4_has_reclaimed_state(child->d_name.name))
347 		return nfs_ok;
348 
349 	status = nfsd4_clear_clid_dir(parent, child);
350 	if (status)
351 		printk("failed to remove client recovery directory %s\n",
352 				child->d_name.name);
353 	/* Keep trying, success or failure: */
354 	return nfs_ok;
355 }
356 
357 void
358 nfsd4_recdir_purge_old(void) {
359 	int status;
360 
361 	if (!rec_dir_init)
362 		return;
363 	status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
364 	if (status == 0)
365 		status = nfsd4_rec_fsync(rec_dir.dentry);
366 	if (status)
367 		printk("nfsd4: failed to purge old clients from recovery"
368 			" directory %s\n", rec_dir.dentry->d_name.name);
369 	return;
370 }
371 
372 static int
373 load_recdir(struct dentry *parent, struct dentry *child)
374 {
375 	if (child->d_name.len != HEXDIR_LEN - 1) {
376 		printk("nfsd4: illegal name %s in recovery directory\n",
377 				child->d_name.name);
378 		/* Keep trying; maybe the others are OK: */
379 		return nfs_ok;
380 	}
381 	nfs4_client_to_reclaim(child->d_name.name);
382 	return nfs_ok;
383 }
384 
385 int
386 nfsd4_recdir_load(void) {
387 	int status;
388 
389 	status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
390 	if (status)
391 		printk("nfsd4: failed loading clients from recovery"
392 			" directory %s\n", rec_dir.dentry->d_name.name);
393 	return status;
394 }
395 
396 /*
397  * Hold reference to the recovery directory.
398  */
399 
400 void
401 nfsd4_init_recdir(char *rec_dirname)
402 {
403 	uid_t			uid = 0;
404 	gid_t			gid = 0;
405 	int 			status;
406 
407 	printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
408 			rec_dirname);
409 
410 	BUG_ON(rec_dir_init);
411 
412 	nfs4_save_user(&uid, &gid);
413 
414 	status = path_lookup(rec_dirname, LOOKUP_FOLLOW, &rec_dir);
415 	if (status == -ENOENT)
416 		printk("NFSD: recovery directory %s doesn't exist\n",
417 				rec_dirname);
418 
419 	if (!status)
420 		rec_dir_init = 1;
421 	nfs4_reset_user(uid, gid);
422 }
423 
424 void
425 nfsd4_shutdown_recdir(void)
426 {
427 	if (!rec_dir_init)
428 		return;
429 	rec_dir_init = 0;
430 	path_release(&rec_dir);
431 }
432