xref: /openbmc/linux/fs/nfsd/nfs4recover.c (revision b04b4f78) 
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 #include <linux/mount.h>
50 
51 #define NFSDDBG_FACILITY                NFSDDBG_PROC
52 
53 /* Globals */
54 static struct path rec_dir;
55 static int rec_dir_init = 0;
56 
57 static int
58 nfs4_save_creds(const struct cred **original_creds)
59 {
60 	struct cred *new;
61 
62 	new = prepare_creds();
63 	if (!new)
64 		return -ENOMEM;
65 
66 	new->fsuid = 0;
67 	new->fsgid = 0;
68 	*original_creds = override_creds(new);
69 	put_cred(new);
70 	return 0;
71 }
72 
73 static void
74 nfs4_reset_creds(const struct cred *original)
75 {
76 	revert_creds(original);
77 }
78 
79 static void
80 md5_to_hex(char *out, char *md5)
81 {
82 	int i;
83 
84 	for (i=0; i<16; i++) {
85 		unsigned char c = md5[i];
86 
87 		*out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
88 		*out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
89 	}
90 	*out = '\0';
91 }
92 
93 __be32
94 nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
95 {
96 	struct xdr_netobj cksum;
97 	struct hash_desc desc;
98 	struct scatterlist sg;
99 	__be32 status = nfserr_resource;
100 
101 	dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
102 			clname->len, clname->data);
103 	desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
104 	desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
105 	if (IS_ERR(desc.tfm))
106 		goto out_no_tfm;
107 	cksum.len = crypto_hash_digestsize(desc.tfm);
108 	cksum.data = kmalloc(cksum.len, GFP_KERNEL);
109 	if (cksum.data == NULL)
110  		goto out;
111 
112 	sg_init_one(&sg, clname->data, clname->len);
113 
114 	if (crypto_hash_digest(&desc, &sg, sg.length, cksum.data))
115 		goto out;
116 
117 	md5_to_hex(dname, cksum.data);
118 
119 	status = nfs_ok;
120 out:
121 	kfree(cksum.data);
122 	crypto_free_hash(desc.tfm);
123 out_no_tfm:
124 	return status;
125 }
126 
127 static void
128 nfsd4_sync_rec_dir(void)
129 {
130 	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
131 	nfsd_sync_dir(rec_dir.dentry);
132 	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
133 }
134 
135 int
136 nfsd4_create_clid_dir(struct nfs4_client *clp)
137 {
138 	const struct cred *original_cred;
139 	char *dname = clp->cl_recdir;
140 	struct dentry *dentry;
141 	int status;
142 
143 	dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
144 
145 	if (!rec_dir_init || clp->cl_firststate)
146 		return 0;
147 
148 	status = nfs4_save_creds(&original_cred);
149 	if (status < 0)
150 		return status;
151 
152 	/* lock the parent */
153 	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
154 
155 	dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
156 	if (IS_ERR(dentry)) {
157 		status = PTR_ERR(dentry);
158 		goto out_unlock;
159 	}
160 	status = -EEXIST;
161 	if (dentry->d_inode) {
162 		dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
163 		goto out_put;
164 	}
165 	status = mnt_want_write(rec_dir.mnt);
166 	if (status)
167 		goto out_put;
168 	status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
169 	mnt_drop_write(rec_dir.mnt);
170 out_put:
171 	dput(dentry);
172 out_unlock:
173 	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
174 	if (status == 0) {
175 		clp->cl_firststate = 1;
176 		nfsd4_sync_rec_dir();
177 	}
178 	nfs4_reset_creds(original_cred);
179 	dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
180 	return status;
181 }
182 
183 typedef int (recdir_func)(struct dentry *, struct dentry *);
184 
185 struct name_list {
186 	char name[HEXDIR_LEN];
187 	struct list_head list;
188 };
189 
190 static int
191 nfsd4_build_namelist(void *arg, const char *name, int namlen,
192 		loff_t offset, u64 ino, unsigned int d_type)
193 {
194 	struct list_head *names = arg;
195 	struct name_list *entry;
196 
197 	if (namlen != HEXDIR_LEN - 1)
198 		return 0;
199 	entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
200 	if (entry == NULL)
201 		return -ENOMEM;
202 	memcpy(entry->name, name, HEXDIR_LEN - 1);
203 	entry->name[HEXDIR_LEN - 1] = '\0';
204 	list_add(&entry->list, names);
205 	return 0;
206 }
207 
208 static int
209 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
210 {
211 	const struct cred *original_cred;
212 	struct file *filp;
213 	LIST_HEAD(names);
214 	struct name_list *entry;
215 	struct dentry *dentry;
216 	int status;
217 
218 	if (!rec_dir_init)
219 		return 0;
220 
221 	status = nfs4_save_creds(&original_cred);
222 	if (status < 0)
223 		return status;
224 
225 	filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY,
226 			   current_cred());
227 	status = PTR_ERR(filp);
228 	if (IS_ERR(filp))
229 		goto out;
230 	status = vfs_readdir(filp, nfsd4_build_namelist, &names);
231 	fput(filp);
232 	mutex_lock(&dir->d_inode->i_mutex);
233 	while (!list_empty(&names)) {
234 		entry = list_entry(names.next, struct name_list, list);
235 
236 		dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
237 		if (IS_ERR(dentry)) {
238 			status = PTR_ERR(dentry);
239 			break;
240 		}
241 		status = f(dir, dentry);
242 		dput(dentry);
243 		if (status)
244 			break;
245 		list_del(&entry->list);
246 		kfree(entry);
247 	}
248 	mutex_unlock(&dir->d_inode->i_mutex);
249 out:
250 	while (!list_empty(&names)) {
251 		entry = list_entry(names.next, struct name_list, list);
252 		list_del(&entry->list);
253 		kfree(entry);
254 	}
255 	nfs4_reset_creds(original_cred);
256 	return status;
257 }
258 
259 static int
260 nfsd4_unlink_clid_dir(char *name, int namlen)
261 {
262 	struct dentry *dentry;
263 	int status;
264 
265 	dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
266 
267 	mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
268 	dentry = lookup_one_len(name, rec_dir.dentry, namlen);
269 	if (IS_ERR(dentry)) {
270 		status = PTR_ERR(dentry);
271 		goto out_unlock;
272 	}
273 	status = -ENOENT;
274 	if (!dentry->d_inode)
275 		goto out;
276 	status = vfs_rmdir(rec_dir.dentry->d_inode, dentry);
277 out:
278 	dput(dentry);
279 out_unlock:
280 	mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
281 	return status;
282 }
283 
284 void
285 nfsd4_remove_clid_dir(struct nfs4_client *clp)
286 {
287 	const struct cred *original_cred;
288 	int status;
289 
290 	if (!rec_dir_init || !clp->cl_firststate)
291 		return;
292 
293 	status = mnt_want_write(rec_dir.mnt);
294 	if (status)
295 		goto out;
296 	clp->cl_firststate = 0;
297 
298 	status = nfs4_save_creds(&original_cred);
299 	if (status < 0)
300 		goto out;
301 
302 	status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
303 	nfs4_reset_creds(original_cred);
304 	if (status == 0)
305 		nfsd4_sync_rec_dir();
306 	mnt_drop_write(rec_dir.mnt);
307 out:
308 	if (status)
309 		printk("NFSD: Failed to remove expired client state directory"
310 				" %.*s\n", HEXDIR_LEN, clp->cl_recdir);
311 	return;
312 }
313 
314 static int
315 purge_old(struct dentry *parent, struct dentry *child)
316 {
317 	int status;
318 
319 	/* note: we currently use this path only for minorversion 0 */
320 	if (nfs4_has_reclaimed_state(child->d_name.name, false))
321 		return 0;
322 
323 	status = vfs_rmdir(parent->d_inode, child);
324 	if (status)
325 		printk("failed to remove client recovery directory %s\n",
326 				child->d_name.name);
327 	/* Keep trying, success or failure: */
328 	return 0;
329 }
330 
331 void
332 nfsd4_recdir_purge_old(void) {
333 	int status;
334 
335 	if (!rec_dir_init)
336 		return;
337 	status = mnt_want_write(rec_dir.mnt);
338 	if (status)
339 		goto out;
340 	status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
341 	if (status == 0)
342 		nfsd4_sync_rec_dir();
343 	mnt_drop_write(rec_dir.mnt);
344 out:
345 	if (status)
346 		printk("nfsd4: failed to purge old clients from recovery"
347 			" directory %s\n", rec_dir.dentry->d_name.name);
348 }
349 
350 static int
351 load_recdir(struct dentry *parent, struct dentry *child)
352 {
353 	if (child->d_name.len != HEXDIR_LEN - 1) {
354 		printk("nfsd4: illegal name %s in recovery directory\n",
355 				child->d_name.name);
356 		/* Keep trying; maybe the others are OK: */
357 		return 0;
358 	}
359 	nfs4_client_to_reclaim(child->d_name.name);
360 	return 0;
361 }
362 
363 int
364 nfsd4_recdir_load(void) {
365 	int status;
366 
367 	status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
368 	if (status)
369 		printk("nfsd4: failed loading clients from recovery"
370 			" directory %s\n", rec_dir.dentry->d_name.name);
371 	return status;
372 }
373 
374 /*
375  * Hold reference to the recovery directory.
376  */
377 
378 void
379 nfsd4_init_recdir(char *rec_dirname)
380 {
381 	const struct cred *original_cred;
382 	int status;
383 
384 	printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
385 			rec_dirname);
386 
387 	BUG_ON(rec_dir_init);
388 
389 	status = nfs4_save_creds(&original_cred);
390 	if (status < 0) {
391 		printk("NFSD: Unable to change credentials to find recovery"
392 		       " directory: error %d\n",
393 		       status);
394 		return;
395 	}
396 
397 	status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
398 			&rec_dir);
399 	if (status)
400 		printk("NFSD: unable to find recovery directory %s\n",
401 				rec_dirname);
402 
403 	if (!status)
404 		rec_dir_init = 1;
405 	nfs4_reset_creds(original_cred);
406 }
407 
408 void
409 nfsd4_shutdown_recdir(void)
410 {
411 	if (!rec_dir_init)
412 		return;
413 	rec_dir_init = 0;
414 	path_put(&rec_dir);
415 }
416