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         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         while (!list_empty(&names)) {
 233                 entry = list_entry(names.next, struct name_list, list);
 234
 235                 dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
 236                 if (IS_ERR(dentry)) {
 237                         status = PTR_ERR(dentry);
 238                         goto out;
 239                 }
 240                 status = f(dir, dentry);
 241                 dput(dentry);
 242                 if (status)
 243                         goto out;
 244                 list_del(&entry->list);
 245                 kfree(entry);
 246         }
 247 out:
 248         while (!list_empty(&names)) {
 249                 entry = list_entry(names.next, struct name_list, list);
 250                 list_del(&entry->list);
 251                 kfree(entry);
 252         }
 253         nfs4_reset_creds(original_cred);
 254         return status;
 255 }
 256
 257 static int
 258 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
 259 {
 260         int status;
 261
 262         if (!S_ISREG(dir->d_inode->i_mode)) {
 263                 printk("nfsd4: non-file found in client recovery directory\n");
 264                 return -EINVAL;
 265         }
 266         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 267         status = vfs_unlink(dir->d_inode, dentry);
 268         mutex_unlock(&dir->d_inode->i_mutex);
 269         return status;
 270 }
 271
 272 static int
 273 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
 274 {
 275         int status;
 276
 277         /* For now this directory should already be empty, but we empty it of
 278          * any regular files anyway, just in case the directory was created by
 279          * a kernel from the future.... */
 280         nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
 281         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 282         status = vfs_rmdir(dir->d_inode, dentry);
 283         mutex_unlock(&dir->d_inode->i_mutex);
 284         return status;
 285 }
 286
 287 static int
 288 nfsd4_unlink_clid_dir(char *name, int namlen)
 289 {
 290         struct dentry *dentry;
 291         int status;
 292
 293         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 294
 295         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 296         dentry = lookup_one_len(name, rec_dir.dentry, namlen);
 297         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 298         if (IS_ERR(dentry)) {
 299                 status = PTR_ERR(dentry);
 300                 return status;
 301         }
 302         status = -ENOENT;
 303         if (!dentry->d_inode)
 304                 goto out;
 305
 306         status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry);
 307 out:
 308         dput(dentry);
 309         return status;
 310 }
 311
 312 void
 313 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 314 {
 315         const struct cred *original_cred;
 316         int status;
 317
 318         if (!rec_dir_init || !clp->cl_firststate)
 319                 return;
 320
 321         status = mnt_want_write(rec_dir.mnt);
 322         if (status)
 323                 goto out;
 324         clp->cl_firststate = 0;
 325
 326         status = nfs4_save_creds(&original_cred);
 327         if (status < 0)
 328                 goto out;
 329
 330         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 331         nfs4_reset_creds(original_cred);
 332         if (status == 0)
 333                 nfsd4_sync_rec_dir();
 334         mnt_drop_write(rec_dir.mnt);
 335 out:
 336         if (status)
 337                 printk("NFSD: Failed to remove expired client state directory"
 338                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 339         return;
 340 }
 341
 342 static int
 343 purge_old(struct dentry *parent, struct dentry *child)
 344 {
 345         int status;
 346
 347         /* note: we currently use this path only for minorversion 0 */
 348         if (nfs4_has_reclaimed_state(child->d_name.name, false))
 349                 return 0;
 350
 351         status = nfsd4_clear_clid_dir(parent, child);
 352         if (status)
 353                 printk("failed to remove client recovery directory %s\n",
 354                                 child->d_name.name);
 355         /* Keep trying, success or failure: */
 356         return 0;
 357 }
 358
 359 void
 360 nfsd4_recdir_purge_old(void) {
 361         int status;
 362
 363         if (!rec_dir_init)
 364                 return;
 365         status = mnt_want_write(rec_dir.mnt);
 366         if (status)
 367                 goto out;
 368         status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
 369         if (status == 0)
 370                 nfsd4_sync_rec_dir();
 371         mnt_drop_write(rec_dir.mnt);
 372 out:
 373         if (status)
 374                 printk("nfsd4: failed to purge old clients from recovery"
 375                         " directory %s\n", rec_dir.dentry->d_name.name);
 376 }
 377
 378 static int
 379 load_recdir(struct dentry *parent, struct dentry *child)
 380 {
 381         if (child->d_name.len != HEXDIR_LEN - 1) {
 382                 printk("nfsd4: illegal name %s in recovery directory\n",
 383                                 child->d_name.name);
 384                 /* Keep trying; maybe the others are OK: */
 385                 return 0;
 386         }
 387         nfs4_client_to_reclaim(child->d_name.name);
 388         return 0;
 389 }
 390
 391 int
 392 nfsd4_recdir_load(void) {
 393         int status;
 394
 395         status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
 396         if (status)
 397                 printk("nfsd4: failed loading clients from recovery"
 398                         " directory %s\n", rec_dir.dentry->d_name.name);
 399         return status;
 400 }
 401
 402 /*
 403  * Hold reference to the recovery directory.
 404  */
 405
 406 void
 407 nfsd4_init_recdir(char *rec_dirname)
 408 {
 409         const struct cred *original_cred;
 410         int status;
 411
 412         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 413                         rec_dirname);
 414
 415         BUG_ON(rec_dir_init);
 416
 417         status = nfs4_save_creds(&original_cred);
 418         if (status < 0) {
 419                 printk("NFSD: Unable to change credentials to find recovery"
 420                        " directory: error %d\n",
 421                        status);
 422                 return;
 423         }
 424
 425         status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
 426                         &rec_dir);
 427         if (status)
 428                 printk("NFSD: unable to find recovery directory %s\n",
 429                                 rec_dirname);
 430
 431         if (!status)
 432                 rec_dir_init = 1;
 433         nfs4_reset_creds(original_cred);
 434 }
 435
 436 void
 437 nfsd4_shutdown_recdir(void)
 438 {
 439         if (!rec_dir_init)
 440                 return;
 441         rec_dir_init = 0;
 442         path_put(&rec_dir);
 443 }