xref: /openbmc/linux/fs/nfsd/nfs4recover.c (revision 87c2ce3b) 
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", CRYPTO_TFM_REQ_MAY_SLEEP);
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 	crypto_free_tfm(tfm);
118 	return status;
119 }
120 
121 static void
122 nfsd4_sync_rec_dir(void)
123 {
124 	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
125 	nfsd_sync_dir(rec_dir.dentry);
126 	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
127 }
128 
129 int
130 nfsd4_create_clid_dir(struct nfs4_client *clp)
131 {
132 	char *dname = clp->cl_recdir;
133 	struct dentry *dentry;
134 	uid_t uid;
135 	gid_t gid;
136 	int status;
137 
138 	dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
139 
140 	if (!rec_dir_init || clp->cl_firststate)
141 		return 0;
142 
143 	nfs4_save_user(&uid, &gid);
144 
145 	/* lock the parent */
146 	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
147 
148 	dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
149 	if (IS_ERR(dentry)) {
150 		status = PTR_ERR(dentry);
151 		goto out_unlock;
152 	}
153 	status = -EEXIST;
154 	if (dentry->d_inode) {
155 		dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
156 		goto out_put;
157 	}
158 	status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
159 out_put:
160 	dput(dentry);
161 out_unlock:
162 	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
163 	if (status == 0) {
164 		clp->cl_firststate = 1;
165 		nfsd4_sync_rec_dir();
166 	}
167 	nfs4_reset_user(uid, gid);
168 	dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
169 	return status;
170 }
171 
172 typedef int (recdir_func)(struct dentry *, struct dentry *);
173 
174 struct dentry_list {
175 	struct dentry *dentry;
176 	struct list_head list;
177 };
178 
179 struct dentry_list_arg {
180 	struct list_head dentries;
181 	struct dentry *parent;
182 };
183 
184 static int
185 nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
186 		loff_t offset, ino_t ino, unsigned int d_type)
187 {
188 	struct dentry_list_arg *dla = arg;
189 	struct list_head *dentries = &dla->dentries;
190 	struct dentry *parent = dla->parent;
191 	struct dentry *dentry;
192 	struct dentry_list *child;
193 
194 	if (name && isdotent(name, namlen))
195 		return nfs_ok;
196 	dentry = lookup_one_len(name, parent, namlen);
197 	if (IS_ERR(dentry))
198 		return PTR_ERR(dentry);
199 	child = kmalloc(sizeof(*child), GFP_KERNEL);
200 	if (child == NULL)
201 		return -ENOMEM;
202 	child->dentry = dentry;
203 	list_add(&child->list, dentries);
204 	return 0;
205 }
206 
207 static int
208 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
209 {
210 	struct file *filp;
211 	struct dentry_list_arg dla = {
212 		.parent = dir,
213 	};
214 	struct list_head *dentries = &dla.dentries;
215 	struct dentry_list *child;
216 	uid_t uid;
217 	gid_t gid;
218 	int status;
219 
220 	if (!rec_dir_init)
221 		return 0;
222 
223 	nfs4_save_user(&uid, &gid);
224 
225 	filp = dentry_open(dget(dir), mntget(rec_dir.mnt),
226 			O_RDWR);
227 	status = PTR_ERR(filp);
228 	if (IS_ERR(filp))
229 		goto out;
230 	INIT_LIST_HEAD(dentries);
231 	status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
232 	fput(filp);
233 	while (!list_empty(dentries)) {
234 		child = list_entry(dentries->next, struct dentry_list, list);
235 		status = f(dir, child->dentry);
236 		if (status)
237 			goto out;
238 		list_del(&child->list);
239 		dput(child->dentry);
240 		kfree(child);
241 	}
242 out:
243 	while (!list_empty(dentries)) {
244 		child = list_entry(dentries->next, struct dentry_list, list);
245 		list_del(&child->list);
246 		dput(child->dentry);
247 		kfree(child);
248 	}
249 	nfs4_reset_user(uid, gid);
250 	return status;
251 }
252 
253 static int
254 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
255 {
256 	int status;
257 
258 	if (!S_ISREG(dir->d_inode->i_mode)) {
259 		printk("nfsd4: non-file found in client recovery directory\n");
260 		return -EINVAL;
261 	}
262 	mutex_lock(&dir->d_inode->i_mutex);
263 	status = vfs_unlink(dir->d_inode, dentry);
264 	mutex_unlock(&dir->d_inode->i_mutex);
265 	return status;
266 }
267 
268 static int
269 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
270 {
271 	int status;
272 
273 	/* For now this directory should already be empty, but we empty it of
274 	 * any regular files anyway, just in case the directory was created by
275 	 * a kernel from the future.... */
276 	nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
277 	mutex_lock(&dir->d_inode->i_mutex);
278 	status = vfs_rmdir(dir->d_inode, dentry);
279 	mutex_unlock(&dir->d_inode->i_mutex);
280 	return status;
281 }
282 
283 static int
284 nfsd4_unlink_clid_dir(char *name, int namlen)
285 {
286 	struct dentry *dentry;
287 	int status;
288 
289 	dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
290 
291 	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
292 	dentry = lookup_one_len(name, rec_dir.dentry, namlen);
293 	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
294 	if (IS_ERR(dentry)) {
295 		status = PTR_ERR(dentry);
296 		return status;
297 	}
298 	status = -ENOENT;
299 	if (!dentry->d_inode)
300 		goto out;
301 
302 	status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry);
303 out:
304 	dput(dentry);
305 	return status;
306 }
307 
308 void
309 nfsd4_remove_clid_dir(struct nfs4_client *clp)
310 {
311 	uid_t uid;
312 	gid_t gid;
313 	int status;
314 
315 	if (!rec_dir_init || !clp->cl_firststate)
316 		return;
317 
318 	clp->cl_firststate = 0;
319 	nfs4_save_user(&uid, &gid);
320 	status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
321 	nfs4_reset_user(uid, gid);
322 	if (status == 0)
323 		nfsd4_sync_rec_dir();
324 	if (status)
325 		printk("NFSD: Failed to remove expired client state directory"
326 				" %.*s\n", HEXDIR_LEN, clp->cl_recdir);
327 	return;
328 }
329 
330 static int
331 purge_old(struct dentry *parent, struct dentry *child)
332 {
333 	int status;
334 
335 	if (nfs4_has_reclaimed_state(child->d_name.name))
336 		return nfs_ok;
337 
338 	status = nfsd4_clear_clid_dir(parent, child);
339 	if (status)
340 		printk("failed to remove client recovery directory %s\n",
341 				child->d_name.name);
342 	/* Keep trying, success or failure: */
343 	return nfs_ok;
344 }
345 
346 void
347 nfsd4_recdir_purge_old(void) {
348 	int status;
349 
350 	if (!rec_dir_init)
351 		return;
352 	status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
353 	if (status == 0)
354 		nfsd4_sync_rec_dir();
355 	if (status)
356 		printk("nfsd4: failed to purge old clients from recovery"
357 			" directory %s\n", rec_dir.dentry->d_name.name);
358 	return;
359 }
360 
361 static int
362 load_recdir(struct dentry *parent, struct dentry *child)
363 {
364 	if (child->d_name.len != HEXDIR_LEN - 1) {
365 		printk("nfsd4: illegal name %s in recovery directory\n",
366 				child->d_name.name);
367 		/* Keep trying; maybe the others are OK: */
368 		return nfs_ok;
369 	}
370 	nfs4_client_to_reclaim(child->d_name.name);
371 	return nfs_ok;
372 }
373 
374 int
375 nfsd4_recdir_load(void) {
376 	int status;
377 
378 	status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
379 	if (status)
380 		printk("nfsd4: failed loading clients from recovery"
381 			" directory %s\n", rec_dir.dentry->d_name.name);
382 	return status;
383 }
384 
385 /*
386  * Hold reference to the recovery directory.
387  */
388 
389 void
390 nfsd4_init_recdir(char *rec_dirname)
391 {
392 	uid_t			uid = 0;
393 	gid_t			gid = 0;
394 	int 			status;
395 
396 	printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
397 			rec_dirname);
398 
399 	BUG_ON(rec_dir_init);
400 
401 	nfs4_save_user(&uid, &gid);
402 
403 	status = path_lookup(rec_dirname, LOOKUP_FOLLOW, &rec_dir);
404 	if (status == -ENOENT)
405 		printk("NFSD: recovery directory %s doesn't exist\n",
406 				rec_dirname);
407 
408 	if (!status)
409 		rec_dir_init = 1;
410 	nfs4_reset_user(uid, gid);
411 }
412 
413 void
414 nfsd4_shutdown_recdir(void)
415 {
416 	if (!rec_dir_init)
417 		return;
418 	rec_dir_init = 0;
419 	path_release(&rec_dir);
420 }
421