fs/nfsd/nfs4recover.c

   1 /*
   2 *  Copyright (c) 2004 The Regents of the University of Michigan.
   3 *  All rights reserved.
   4 *
   5 *  Andy Adamson <andros@citi.umich.edu>
   6 *
   7 *  Redistribution and use in source and binary forms, with or without
   8 *  modification, are permitted provided that the following conditions
   9 *  are met:
  10 *
  11 *  1. Redistributions of source code must retain the above copyright
  12 *     notice, this list of conditions and the following disclaimer.
  13 *  2. Redistributions in binary form must reproduce the above copyright
  14 *     notice, this list of conditions and the following disclaimer in the
  15 *     documentation and/or other materials provided with the distribution.
  16 *  3. Neither the name of the University nor the names of its
  17 *     contributors may be used to endorse or promote products derived
  18 *     from this software without specific prior written permission.
  19 *
  20 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  21 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  22 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  23 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  27 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  28 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  29 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  30 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31 *
  32 */
  33
  34 #include <linux/file.h>
  35 #include <linux/slab.h>
  36 #include <linux/namei.h>
  37 #include <linux/crypto.h>
  38 #include <linux/sched.h>
  39
  40 #include "nfsd.h"
  41 #include "state.h"
  42 #include "vfs.h"
  43
  44 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  45
  46 /* Globals */
  47 static struct file *rec_file;
  48 static char user_recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
  49
  50 static int
  51 nfs4_save_creds(const struct cred **original_creds)
  52 {
  53         struct cred *new;
  54
  55         new = prepare_creds();
  56         if (!new)
  57                 return -ENOMEM;
  58
  59         new->fsuid = 0;
  60         new->fsgid = 0;
  61         *original_creds = override_creds(new);
  62         put_cred(new);
  63         return 0;
  64 }
  65
  66 static void
  67 nfs4_reset_creds(const struct cred *original)
  68 {
  69         revert_creds(original);
  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 __be32
  87 nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
  88 {
  89         struct xdr_netobj cksum;
  90         struct hash_desc desc;
  91         struct scatterlist sg;
  92         __be32 status = nfserr_jukebox;
  93
  94         dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
  95                         clname->len, clname->data);
  96         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
  97         desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
  98         if (IS_ERR(desc.tfm))
  99                 goto out_no_tfm;
 100         cksum.len = crypto_hash_digestsize(desc.tfm);
 101         cksum.data = kmalloc(cksum.len, GFP_KERNEL);
 102         if (cksum.data == NULL)
 103                 goto out;
 104
 105         sg_init_one(&sg, clname->data, clname->len);
 106
 107         if (crypto_hash_digest(&desc, &sg, sg.length, cksum.data))
 108                 goto out;
 109
 110         md5_to_hex(dname, cksum.data);
 111
 112         status = nfs_ok;
 113 out:
 114         kfree(cksum.data);
 115         crypto_free_hash(desc.tfm);
 116 out_no_tfm:
 117         return status;
 118 }
 119
 120 void nfsd4_create_clid_dir(struct nfs4_client *clp)
 121 {
 122         const struct cred *original_cred;
 123         char *dname = clp->cl_recdir;
 124         struct dentry *dir, *dentry;
 125         int status;
 126
 127         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 128
 129         if (clp->cl_firststate)
 130                 return;
 131         clp->cl_firststate = 1;
 132         if (!rec_file)
 133                 return;
 134         status = nfs4_save_creds(&original_cred);
 135         if (status < 0)
 136                 return;
 137
 138         dir = rec_file->f_path.dentry;
 139         /* lock the parent */
 140         mutex_lock(&dir->d_inode->i_mutex);
 141
 142         dentry = lookup_one_len(dname, dir, HEXDIR_LEN-1);
 143         if (IS_ERR(dentry)) {
 144                 status = PTR_ERR(dentry);
 145                 goto out_unlock;
 146         }
 147         if (dentry->d_inode)
 148                 /*
 149                  * In the 4.1 case, where we're called from
 150                  * reclaim_complete(), records from the previous reboot
 151                  * may still be left, so this is OK.
 152                  *
 153                  * In the 4.0 case, we should never get here; but we may
 154                  * as well be forgiving and just succeed silently.
 155                  */
 156                 goto out_put;
 157         status = mnt_want_write(rec_file->f_path.mnt);
 158         if (status)
 159                 goto out_put;
 160         status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);
 161         mnt_drop_write(rec_file->f_path.mnt);
 162 out_put:
 163         dput(dentry);
 164 out_unlock:
 165         mutex_unlock(&dir->d_inode->i_mutex);
 166         if (status == 0)
 167                 vfs_fsync(rec_file, 0);
 168         else
 169                 printk(KERN_ERR "NFSD: failed to write recovery record"
 170                                 " (err %d); please check that %s exists"
 171                                 " and is writeable", status,
 172                                 user_recovery_dirname);
 173         nfs4_reset_creds(original_cred);
 174 }
 175
 176 typedef int (recdir_func)(struct dentry *, struct dentry *);
 177
 178 struct name_list {
 179         char name[HEXDIR_LEN];
 180         struct list_head list;
 181 };
 182
 183 static int
 184 nfsd4_build_namelist(void *arg, const char *name, int namlen,
 185                 loff_t offset, u64 ino, unsigned int d_type)
 186 {
 187         struct list_head *names = arg;
 188         struct name_list *entry;
 189
 190         if (namlen != HEXDIR_LEN - 1)
 191                 return 0;
 192         entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
 193         if (entry == NULL)
 194                 return -ENOMEM;
 195         memcpy(entry->name, name, HEXDIR_LEN - 1);
 196         entry->name[HEXDIR_LEN - 1] = '\0';
 197         list_add(&entry->list, names);
 198         return 0;
 199 }
 200
 201 static int
 202 nfsd4_list_rec_dir(recdir_func *f)
 203 {
 204         const struct cred *original_cred;
 205         struct dentry *dir = rec_file->f_path.dentry;
 206         LIST_HEAD(names);
 207         int status;
 208
 209         status = nfs4_save_creds(&original_cred);
 210         if (status < 0)
 211                 return status;
 212
 213         status = vfs_llseek(rec_file, 0, SEEK_SET);
 214         if (status < 0) {
 215                 nfs4_reset_creds(original_cred);
 216                 return status;
 217         }
 218
 219         status = vfs_readdir(rec_file, nfsd4_build_namelist, &names);
 220         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 221         while (!list_empty(&names)) {
 222                 struct name_list *entry;
 223                 entry = list_entry(names.next, struct name_list, list);
 224                 if (!status) {
 225                         struct dentry *dentry;
 226                         dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
 227                         if (IS_ERR(dentry)) {
 228                                 status = PTR_ERR(dentry);
 229                                 break;
 230                         }
 231                         status = f(dir, dentry);
 232                         dput(dentry);
 233                 }
 234                 list_del(&entry->list);
 235                 kfree(entry);
 236         }
 237         mutex_unlock(&dir->d_inode->i_mutex);
 238         nfs4_reset_creds(original_cred);
 239         return status;
 240 }
 241
 242 static int
 243 nfsd4_unlink_clid_dir(char *name, int namlen)
 244 {
 245         struct dentry *dir, *dentry;
 246         int status;
 247
 248         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 249
 250         dir = rec_file->f_path.dentry;
 251         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 252         dentry = lookup_one_len(name, dir, namlen);
 253         if (IS_ERR(dentry)) {
 254                 status = PTR_ERR(dentry);
 255                 goto out_unlock;
 256         }
 257         status = -ENOENT;
 258         if (!dentry->d_inode)
 259                 goto out;
 260         status = vfs_rmdir(dir->d_inode, dentry);
 261 out:
 262         dput(dentry);
 263 out_unlock:
 264         mutex_unlock(&dir->d_inode->i_mutex);
 265         return status;
 266 }
 267
 268 void
 269 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 270 {
 271         const struct cred *original_cred;
 272         int status;
 273
 274         if (!rec_file || !clp->cl_firststate)
 275                 return;
 276
 277         status = mnt_want_write(rec_file->f_path.mnt);
 278         if (status)
 279                 goto out;
 280         clp->cl_firststate = 0;
 281
 282         status = nfs4_save_creds(&original_cred);
 283         if (status < 0)
 284                 goto out;
 285
 286         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 287         nfs4_reset_creds(original_cred);
 288         if (status == 0)
 289                 vfs_fsync(rec_file, 0);
 290         mnt_drop_write(rec_file->f_path.mnt);
 291 out:
 292         if (status)
 293                 printk("NFSD: Failed to remove expired client state directory"
 294                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 295         return;
 296 }
 297
 298 static int
 299 purge_old(struct dentry *parent, struct dentry *child)
 300 {
 301         int status;
 302
 303         if (nfs4_has_reclaimed_state(child->d_name.name, false))
 304                 return 0;
 305
 306         status = vfs_rmdir(parent->d_inode, child);
 307         if (status)
 308                 printk("failed to remove client recovery directory %s\n",
 309                                 child->d_name.name);
 310         /* Keep trying, success or failure: */
 311         return 0;
 312 }
 313
 314 void
 315 nfsd4_recdir_purge_old(void) {
 316         int status;
 317
 318         if (!rec_file)
 319                 return;
 320         status = mnt_want_write(rec_file->f_path.mnt);
 321         if (status)
 322                 goto out;
 323         status = nfsd4_list_rec_dir(purge_old);
 324         if (status == 0)
 325                 vfs_fsync(rec_file, 0);
 326         mnt_drop_write(rec_file->f_path.mnt);
 327 out:
 328         if (status)
 329                 printk("nfsd4: failed to purge old clients from recovery"
 330                         " directory %s\n", rec_file->f_path.dentry->d_name.name);
 331 }
 332
 333 static int
 334 load_recdir(struct dentry *parent, struct dentry *child)
 335 {
 336         if (child->d_name.len != HEXDIR_LEN - 1) {
 337                 printk("nfsd4: illegal name %s in recovery directory\n",
 338                                 child->d_name.name);
 339                 /* Keep trying; maybe the others are OK: */
 340                 return 0;
 341         }
 342         nfs4_client_to_reclaim(child->d_name.name);
 343         return 0;
 344 }
 345
 346 int
 347 nfsd4_recdir_load(void) {
 348         int status;
 349
 350         if (!rec_file)
 351                 return 0;
 352
 353         status = nfsd4_list_rec_dir(load_recdir);
 354         if (status)
 355                 printk("nfsd4: failed loading clients from recovery"
 356                         " directory %s\n", rec_file->f_path.dentry->d_name.name);
 357         return status;
 358 }
 359
 360 /*
 361  * Hold reference to the recovery directory.
 362  */
 363
 364 void
 365 nfsd4_init_recdir()
 366 {
 367         const struct cred *original_cred;
 368         int status;
 369
 370         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 371                         user_recovery_dirname);
 372
 373         BUG_ON(rec_file);
 374
 375         status = nfs4_save_creds(&original_cred);
 376         if (status < 0) {
 377                 printk("NFSD: Unable to change credentials to find recovery"
 378                        " directory: error %d\n",
 379                        status);
 380                 return;
 381         }
 382
 383         rec_file = filp_open(user_recovery_dirname, O_RDONLY | O_DIRECTORY, 0);
 384         if (IS_ERR(rec_file)) {
 385                 printk("NFSD: unable to find recovery directory %s\n",
 386                                 user_recovery_dirname);
 387                 rec_file = NULL;
 388         }
 389
 390         nfs4_reset_creds(original_cred);
 391 }
 392
 393 void
 394 nfsd4_shutdown_recdir(void)
 395 {
 396         if (!rec_file)
 397                 return;
 398         fput(rec_file);
 399         rec_file = NULL;
 400 }
 401
 402 /*
 403  * Change the NFSv4 recovery directory to recdir.
 404  */
 405 int
 406 nfs4_reset_recoverydir(char *recdir)
 407 {
 408         int status;
 409         struct path path;
 410
 411         status = kern_path(recdir, LOOKUP_FOLLOW, &path);
 412         if (status)
 413                 return status;
 414         status = -ENOTDIR;
 415         if (S_ISDIR(path.dentry->d_inode->i_mode)) {
 416                 strcpy(user_recovery_dirname, recdir);
 417                 status = 0;
 418         }
 419         path_put(&path);
 420         return status;
 421 }
 422
 423 char *
 424 nfs4_recoverydir(void)
 425 {
 426         return user_recovery_dirname;
 427 }