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
nfs4_save_creds(const struct cred ** original_creds)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
nfs4_reset_creds(const struct cred * original)74 nfs4_reset_creds(const struct cred *original)
75 {
76 revert_creds(original);
77 }
78
79 static void
md5_to_hex(char * out,char * md5)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
nfs4_make_rec_clidname(char * dname,struct xdr_netobj * clname)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
nfsd4_sync_rec_dir(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
nfsd4_create_clid_dir(struct nfs4_client * clp)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 dentry_list {
186 struct dentry *dentry;
187 struct list_head list;
188 };
189
190 struct dentry_list_arg {
191 struct list_head dentries;
192 struct dentry *parent;
193 };
194
195 static int
nfsd4_build_dentrylist(void * arg,const char * name,int namlen,loff_t offset,u64 ino,unsigned int d_type)196 nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
197 loff_t offset, u64 ino, unsigned int d_type)
198 {
199 struct dentry_list_arg *dla = arg;
200 struct list_head *dentries = &dla->dentries;
201 struct dentry *parent = dla->parent;
202 struct dentry *dentry;
203 struct dentry_list *child;
204
205 if (name && isdotent(name, namlen))
206 return 0;
207 dentry = lookup_one_len(name, parent, namlen);
208 if (IS_ERR(dentry))
209 return PTR_ERR(dentry);
210 child = kmalloc(sizeof(*child), GFP_KERNEL);
211 if (child == NULL)
212 return -ENOMEM;
213 child->dentry = dentry;
214 list_add(&child->list, dentries);
215 return 0;
216 }
217
218 static int
nfsd4_list_rec_dir(struct dentry * dir,recdir_func * f)219 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
220 {
221 const struct cred *original_cred;
222 struct file *filp;
223 struct dentry_list_arg dla = {
224 .parent = dir,
225 };
226 struct list_head *dentries = &dla.dentries;
227 struct dentry_list *child;
228 int status;
229
230 if (!rec_dir_init)
231 return 0;
232
233 status = nfs4_save_creds(&original_cred);
234 if (status < 0)
235 return status;
236 INIT_LIST_HEAD(dentries);
237
238 filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY,
239 current_cred());
240 status = PTR_ERR(filp);
241 if (IS_ERR(filp))
242 goto out;
243 INIT_LIST_HEAD(dentries);
244 status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
245 fput(filp);
246 while (!list_empty(dentries)) {
247 child = list_entry(dentries->next, struct dentry_list, list);
248 status = f(dir, child->dentry);
249 if (status)
250 goto out;
251 list_del(&child->list);
252 dput(child->dentry);
253 kfree(child);
254 }
255 out:
256 while (!list_empty(dentries)) {
257 child = list_entry(dentries->next, struct dentry_list, list);
258 list_del(&child->list);
259 dput(child->dentry);
260 kfree(child);
261 }
262 nfs4_reset_creds(original_cred);
263 return status;
264 }
265
266 static int
nfsd4_remove_clid_file(struct dentry * dir,struct dentry * dentry)267 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
268 {
269 int status;
270
271 if (!S_ISREG(dir->d_inode->i_mode)) {
272 printk("nfsd4: non-file found in client recovery directory\n");
273 return -EINVAL;
274 }
275 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
276 status = vfs_unlink(dir->d_inode, dentry);
277 mutex_unlock(&dir->d_inode->i_mutex);
278 return status;
279 }
280
281 static int
nfsd4_clear_clid_dir(struct dentry * dir,struct dentry * dentry)282 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
283 {
284 int status;
285
286 /* For now this directory should already be empty, but we empty it of
287 * any regular files anyway, just in case the directory was created by
288 * a kernel from the future.... */
289 nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
290 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
291 status = vfs_rmdir(dir->d_inode, dentry);
292 mutex_unlock(&dir->d_inode->i_mutex);
293 return status;
294 }
295
296 static int
nfsd4_unlink_clid_dir(char * name,int namlen)297 nfsd4_unlink_clid_dir(char *name, int namlen)
298 {
299 struct dentry *dentry;
300 int status;
301
302 dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
303
304 mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
305 dentry = lookup_one_len(name, rec_dir.dentry, namlen);
306 mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
307 if (IS_ERR(dentry)) {
308 status = PTR_ERR(dentry);
309 return status;
310 }
311 status = -ENOENT;
312 if (!dentry->d_inode)
313 goto out;
314
315 status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry);
316 out:
317 dput(dentry);
318 return status;
319 }
320
321 void
nfsd4_remove_clid_dir(struct nfs4_client * clp)322 nfsd4_remove_clid_dir(struct nfs4_client *clp)
323 {
324 const struct cred *original_cred;
325 int status;
326
327 if (!rec_dir_init || !clp->cl_firststate)
328 return;
329
330 status = mnt_want_write(rec_dir.mnt);
331 if (status)
332 goto out;
333 clp->cl_firststate = 0;
334
335 status = nfs4_save_creds(&original_cred);
336 if (status < 0)
337 goto out;
338
339 status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
340 nfs4_reset_creds(original_cred);
341 if (status == 0)
342 nfsd4_sync_rec_dir();
343 mnt_drop_write(rec_dir.mnt);
344 out:
345 if (status)
346 printk("NFSD: Failed to remove expired client state directory"
347 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
348 return;
349 }
350
351 static int
purge_old(struct dentry * parent,struct dentry * child)352 purge_old(struct dentry *parent, struct dentry *child)
353 {
354 int status;
355
356 if (nfs4_has_reclaimed_state(child->d_name.name))
357 return 0;
358
359 status = nfsd4_clear_clid_dir(parent, child);
360 if (status)
361 printk("failed to remove client recovery directory %s\n",
362 child->d_name.name);
363 /* Keep trying, success or failure: */
364 return 0;
365 }
366
367 void
nfsd4_recdir_purge_old(void)368 nfsd4_recdir_purge_old(void) {
369 int status;
370
371 if (!rec_dir_init)
372 return;
373 status = mnt_want_write(rec_dir.mnt);
374 if (status)
375 goto out;
376 status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
377 if (status == 0)
378 nfsd4_sync_rec_dir();
379 mnt_drop_write(rec_dir.mnt);
380 out:
381 if (status)
382 printk("nfsd4: failed to purge old clients from recovery"
383 " directory %s\n", rec_dir.dentry->d_name.name);
384 }
385
386 static int
load_recdir(struct dentry * parent,struct dentry * child)387 load_recdir(struct dentry *parent, struct dentry *child)
388 {
389 if (child->d_name.len != HEXDIR_LEN - 1) {
390 printk("nfsd4: illegal name %s in recovery directory\n",
391 child->d_name.name);
392 /* Keep trying; maybe the others are OK: */
393 return 0;
394 }
395 nfs4_client_to_reclaim(child->d_name.name);
396 return 0;
397 }
398
399 int
nfsd4_recdir_load(void)400 nfsd4_recdir_load(void) {
401 int status;
402
403 status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
404 if (status)
405 printk("nfsd4: failed loading clients from recovery"
406 " directory %s\n", rec_dir.dentry->d_name.name);
407 return status;
408 }
409
410 /*
411 * Hold reference to the recovery directory.
412 */
413
414 void
nfsd4_init_recdir(char * rec_dirname)415 nfsd4_init_recdir(char *rec_dirname)
416 {
417 const struct cred *original_cred;
418 int status;
419
420 printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
421 rec_dirname);
422
423 BUG_ON(rec_dir_init);
424
425 status = nfs4_save_creds(&original_cred);
426 if (status < 0) {
427 printk("NFSD: Unable to change credentials to find recovery"
428 " directory: error %d\n",
429 status);
430 return;
431 }
432
433 status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
434 &rec_dir);
435 if (status)
436 printk("NFSD: unable to find recovery directory %s\n",
437 rec_dirname);
438
439 if (!status)
440 rec_dir_init = 1;
441 nfs4_reset_creds(original_cred);
442 }
443
444 void
nfsd4_shutdown_recdir(void)445 nfsd4_shutdown_recdir(void)
446 {
447 if (!rec_dir_init)
448 return;
449 rec_dir_init = 0;
450 path_put(&rec_dir);
451 }
452