fs/nfsd/nfs4recover.c

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