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 int
 121 nfsd4_create_clid_dir(struct nfs4_client *clp)
 122 {
 123         const struct cred *original_cred;
 124         char *dname = clp->cl_recdir;
 125         struct dentry *dir, *dentry;
 126         int status;
 127
 128         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 129
 130         if (!rec_file || clp->cl_firststate)
 131                 return 0;
 132
 133         clp->cl_firststate = 1;
 134         status = nfs4_save_creds(&original_cred);
 135         if (status < 0)
 136                 return status;
 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         status = -EEXIST;
 148         if (dentry->d_inode)
 149                 goto out_put;
 150         status = mnt_want_write(rec_file->f_path.mnt);
 151         if (status)
 152                 goto out_put;
 153         status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);
 154         mnt_drop_write(rec_file->f_path.mnt);
 155 out_put:
 156         dput(dentry);
 157 out_unlock:
 158         mutex_unlock(&dir->d_inode->i_mutex);
 159         if (status == 0)
 160                 vfs_fsync(rec_file, 0);
 161         else
 162                 printk(KERN_ERR "NFSD: failed to write recovery record"
 163                                 " (err %d); please check that %s exists"
 164                                 " and is writeable", status,
 165                                 user_recovery_dirname);
 166         nfs4_reset_creds(original_cred);
 167         return status;
 168 }
 169
 170 typedef int (recdir_func)(struct dentry *, struct dentry *);
 171
 172 struct name_list {
 173         char name[HEXDIR_LEN];
 174         struct list_head list;
 175 };
 176
 177 static int
 178 nfsd4_build_namelist(void *arg, const char *name, int namlen,
 179                 loff_t offset, u64 ino, unsigned int d_type)
 180 {
 181         struct list_head *names = arg;
 182         struct name_list *entry;
 183
 184         if (namlen != HEXDIR_LEN - 1)
 185                 return 0;
 186         entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
 187         if (entry == NULL)
 188                 return -ENOMEM;
 189         memcpy(entry->name, name, HEXDIR_LEN - 1);
 190         entry->name[HEXDIR_LEN - 1] = '\0';
 191         list_add(&entry->list, names);
 192         return 0;
 193 }
 194
 195 static int
 196 nfsd4_list_rec_dir(recdir_func *f)
 197 {
 198         const struct cred *original_cred;
 199         struct dentry *dir = rec_file->f_path.dentry;
 200         LIST_HEAD(names);
 201         int status;
 202
 203         status = nfs4_save_creds(&original_cred);
 204         if (status < 0)
 205                 return status;
 206
 207         status = vfs_llseek(rec_file, 0, SEEK_SET);
 208         if (status < 0) {
 209                 nfs4_reset_creds(original_cred);
 210                 return status;
 211         }
 212
 213         status = vfs_readdir(rec_file, nfsd4_build_namelist, &names);
 214         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 215         while (!list_empty(&names)) {
 216                 struct name_list *entry;
 217                 entry = list_entry(names.next, struct name_list, list);
 218                 if (!status) {
 219                         struct dentry *dentry;
 220                         dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
 221                         if (IS_ERR(dentry)) {
 222                                 status = PTR_ERR(dentry);
 223                                 break;
 224                         }
 225                         status = f(dir, dentry);
 226                         dput(dentry);
 227                 }
 228                 list_del(&entry->list);
 229                 kfree(entry);
 230         }
 231         mutex_unlock(&dir->d_inode->i_mutex);
 232         nfs4_reset_creds(original_cred);
 233         return status;
 234 }
 235
 236 static int
 237 nfsd4_unlink_clid_dir(char *name, int namlen)
 238 {
 239         struct dentry *dir, *dentry;
 240         int status;
 241
 242         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 243
 244         dir = rec_file->f_path.dentry;
 245         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 246         dentry = lookup_one_len(name, dir, namlen);
 247         if (IS_ERR(dentry)) {
 248                 status = PTR_ERR(dentry);
 249                 goto out_unlock;
 250         }
 251         status = -ENOENT;
 252         if (!dentry->d_inode)
 253                 goto out;
 254         status = vfs_rmdir(dir->d_inode, dentry);
 255 out:
 256         dput(dentry);
 257 out_unlock:
 258         mutex_unlock(&dir->d_inode->i_mutex);
 259         return status;
 260 }
 261
 262 void
 263 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 264 {
 265         const struct cred *original_cred;
 266         int status;
 267
 268         if (!rec_file || !clp->cl_firststate)
 269                 return;
 270
 271         status = mnt_want_write(rec_file->f_path.mnt);
 272         if (status)
 273                 goto out;
 274         clp->cl_firststate = 0;
 275
 276         status = nfs4_save_creds(&original_cred);
 277         if (status < 0)
 278                 goto out;
 279
 280         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 281         nfs4_reset_creds(original_cred);
 282         if (status == 0)
 283                 vfs_fsync(rec_file, 0);
 284         mnt_drop_write(rec_file->f_path.mnt);
 285 out:
 286         if (status)
 287                 printk("NFSD: Failed to remove expired client state directory"
 288                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 289         return;
 290 }
 291
 292 static int
 293 purge_old(struct dentry *parent, struct dentry *child)
 294 {
 295         int status;
 296
 297         if (nfs4_has_reclaimed_state(child->d_name.name, false))
 298                 return 0;
 299
 300         status = vfs_rmdir(parent->d_inode, child);
 301         if (status)
 302                 printk("failed to remove client recovery directory %s\n",
 303                                 child->d_name.name);
 304         /* Keep trying, success or failure: */
 305         return 0;
 306 }
 307
 308 void
 309 nfsd4_recdir_purge_old(void) {
 310         int status;
 311
 312         if (!rec_file)
 313                 return;
 314         status = mnt_want_write(rec_file->f_path.mnt);
 315         if (status)
 316                 goto out;
 317         status = nfsd4_list_rec_dir(purge_old);
 318         if (status == 0)
 319                 vfs_fsync(rec_file, 0);
 320         mnt_drop_write(rec_file->f_path.mnt);
 321 out:
 322         if (status)
 323                 printk("nfsd4: failed to purge old clients from recovery"
 324                         " directory %s\n", rec_file->f_path.dentry->d_name.name);
 325 }
 326
 327 static int
 328 load_recdir(struct dentry *parent, struct dentry *child)
 329 {
 330         if (child->d_name.len != HEXDIR_LEN - 1) {
 331                 printk("nfsd4: illegal name %s in recovery directory\n",
 332                                 child->d_name.name);
 333                 /* Keep trying; maybe the others are OK: */
 334                 return 0;
 335         }
 336         nfs4_client_to_reclaim(child->d_name.name);
 337         return 0;
 338 }
 339
 340 int
 341 nfsd4_recdir_load(void) {
 342         int status;
 343
 344         if (!rec_file)
 345                 return 0;
 346
 347         status = nfsd4_list_rec_dir(load_recdir);
 348         if (status)
 349                 printk("nfsd4: failed loading clients from recovery"
 350                         " directory %s\n", rec_file->f_path.dentry->d_name.name);
 351         return status;
 352 }
 353
 354 /*
 355  * Hold reference to the recovery directory.
 356  */
 357
 358 void
 359 nfsd4_init_recdir()
 360 {
 361         const struct cred *original_cred;
 362         int status;
 363
 364         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 365                         user_recovery_dirname);
 366
 367         BUG_ON(rec_file);
 368
 369         status = nfs4_save_creds(&original_cred);
 370         if (status < 0) {
 371                 printk("NFSD: Unable to change credentials to find recovery"
 372                        " directory: error %d\n",
 373                        status);
 374                 return;
 375         }
 376
 377         rec_file = filp_open(user_recovery_dirname, O_RDONLY | O_DIRECTORY, 0);
 378         if (IS_ERR(rec_file)) {
 379                 printk("NFSD: unable to find recovery directory %s\n",
 380                                 user_recovery_dirname);
 381                 rec_file = NULL;
 382         }
 383
 384         nfs4_reset_creds(original_cred);
 385 }
 386
 387 void
 388 nfsd4_shutdown_recdir(void)
 389 {
 390         if (!rec_file)
 391                 return;
 392         fput(rec_file);
 393         rec_file = NULL;
 394 }
 395
 396 /*
 397  * Change the NFSv4 recovery directory to recdir.
 398  */
 399 int
 400 nfs4_reset_recoverydir(char *recdir)
 401 {
 402         int status;
 403         struct path path;
 404
 405         status = kern_path(recdir, LOOKUP_FOLLOW, &path);
 406         if (status)
 407                 return status;
 408         status = -ENOTDIR;
 409         if (S_ISDIR(path.dentry->d_inode->i_mode)) {
 410                 strcpy(user_recovery_dirname, recdir);
 411                 status = 0;
 412         }
 413         path_put(&path);
 414         return status;
 415 }
 416
 417 char *
 418 nfs4_recoverydir(void)
 419 {
 420         return user_recovery_dirname;
 421 }