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
  50 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  51
  52 /* Globals */
  53 static struct nameidata rec_dir;
  54 static int rec_dir_init = 0;
  55
  56 static void
  57 nfs4_save_user(uid_t *saveuid, gid_t *savegid)
  58 {
  59         *saveuid = current->fsuid;
  60         *savegid = current->fsgid;
  61         current->fsuid = 0;
  62         current->fsgid = 0;
  63 }
  64
  65 static void
  66 nfs4_reset_user(uid_t saveuid, gid_t savegid)
  67 {
  68         current->fsuid = saveuid;
  69         current->fsgid = savegid;
  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_resource;
  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         kfree(cksum.data);
 113         status = nfs_ok;
 114 out:
 115         crypto_free_hash(desc.tfm);
 116 out_no_tfm:
 117         return status;
 118 }
 119
 120 static void
 121 nfsd4_sync_rec_dir(void)
 122 {
 123         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 124         nfsd_sync_dir(rec_dir.dentry);
 125         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 126 }
 127
 128 int
 129 nfsd4_create_clid_dir(struct nfs4_client *clp)
 130 {
 131         char *dname = clp->cl_recdir;
 132         struct dentry *dentry;
 133         uid_t uid;
 134         gid_t gid;
 135         int status;
 136
 137         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 138
 139         if (!rec_dir_init || clp->cl_firststate)
 140                 return 0;
 141
 142         nfs4_save_user(&uid, &gid);
 143
 144         /* lock the parent */
 145         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 146
 147         dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
 148         if (IS_ERR(dentry)) {
 149                 status = PTR_ERR(dentry);
 150                 goto out_unlock;
 151         }
 152         status = -EEXIST;
 153         if (dentry->d_inode) {
 154                 dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
 155                 goto out_put;
 156         }
 157         status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
 158 out_put:
 159         dput(dentry);
 160 out_unlock:
 161         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 162         if (status == 0) {
 163                 clp->cl_firststate = 1;
 164                 nfsd4_sync_rec_dir();
 165         }
 166         nfs4_reset_user(uid, gid);
 167         dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
 168         return status;
 169 }
 170
 171 typedef int (recdir_func)(struct dentry *, struct dentry *);
 172
 173 struct dentry_list {
 174         struct dentry *dentry;
 175         struct list_head list;
 176 };
 177
 178 struct dentry_list_arg {
 179         struct list_head dentries;
 180         struct dentry *parent;
 181 };
 182
 183 static int
 184 nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
 185                 loff_t offset, u64 ino, unsigned int d_type)
 186 {
 187         struct dentry_list_arg *dla = arg;
 188         struct list_head *dentries = &dla->dentries;
 189         struct dentry *parent = dla->parent;
 190         struct dentry *dentry;
 191         struct dentry_list *child;
 192
 193         if (name && isdotent(name, namlen))
 194                 return 0;
 195         dentry = lookup_one_len(name, parent, namlen);
 196         if (IS_ERR(dentry))
 197                 return PTR_ERR(dentry);
 198         child = kmalloc(sizeof(*child), GFP_KERNEL);
 199         if (child == NULL)
 200                 return -ENOMEM;
 201         child->dentry = dentry;
 202         list_add(&child->list, dentries);
 203         return 0;
 204 }
 205
 206 static int
 207 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
 208 {
 209         struct file *filp;
 210         struct dentry_list_arg dla = {
 211                 .parent = dir,
 212         };
 213         struct list_head *dentries = &dla.dentries;
 214         struct dentry_list *child;
 215         uid_t uid;
 216         gid_t gid;
 217         int status;
 218
 219         if (!rec_dir_init)
 220                 return 0;
 221
 222         nfs4_save_user(&uid, &gid);
 223
 224         filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY);
 225         status = PTR_ERR(filp);
 226         if (IS_ERR(filp))
 227                 goto out;
 228         INIT_LIST_HEAD(dentries);
 229         status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
 230         fput(filp);
 231         while (!list_empty(dentries)) {
 232                 child = list_entry(dentries->next, struct dentry_list, list);
 233                 status = f(dir, child->dentry);
 234                 if (status)
 235                         goto out;
 236                 list_del(&child->list);
 237                 dput(child->dentry);
 238                 kfree(child);
 239         }
 240 out:
 241         while (!list_empty(dentries)) {
 242                 child = list_entry(dentries->next, struct dentry_list, list);
 243                 list_del(&child->list);
 244                 dput(child->dentry);
 245                 kfree(child);
 246         }
 247         nfs4_reset_user(uid, gid);
 248         return status;
 249 }
 250
 251 static int
 252 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
 253 {
 254         int status;
 255
 256         if (!S_ISREG(dir->d_inode->i_mode)) {
 257                 printk("nfsd4: non-file found in client recovery directory\n");
 258                 return -EINVAL;
 259         }
 260         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 261         status = vfs_unlink(dir->d_inode, dentry);
 262         mutex_unlock(&dir->d_inode->i_mutex);
 263         return status;
 264 }
 265
 266 static int
 267 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
 268 {
 269         int status;
 270
 271         /* For now this directory should already be empty, but we empty it of
 272          * any regular files anyway, just in case the directory was created by
 273          * a kernel from the future.... */
 274         nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
 275         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 276         status = vfs_rmdir(dir->d_inode, dentry);
 277         mutex_unlock(&dir->d_inode->i_mutex);
 278         return status;
 279 }
 280
 281 static int
 282 nfsd4_unlink_clid_dir(char *name, int namlen)
 283 {
 284         struct dentry *dentry;
 285         int status;
 286
 287         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 288
 289         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 290         dentry = lookup_one_len(name, rec_dir.dentry, namlen);
 291         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 292         if (IS_ERR(dentry)) {
 293                 status = PTR_ERR(dentry);
 294                 return status;
 295         }
 296         status = -ENOENT;
 297         if (!dentry->d_inode)
 298                 goto out;
 299
 300         status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry);
 301 out:
 302         dput(dentry);
 303         return status;
 304 }
 305
 306 void
 307 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 308 {
 309         uid_t uid;
 310         gid_t gid;
 311         int status;
 312
 313         if (!rec_dir_init || !clp->cl_firststate)
 314                 return;
 315
 316         clp->cl_firststate = 0;
 317         nfs4_save_user(&uid, &gid);
 318         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 319         nfs4_reset_user(uid, gid);
 320         if (status == 0)
 321                 nfsd4_sync_rec_dir();
 322         if (status)
 323                 printk("NFSD: Failed to remove expired client state directory"
 324                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 325         return;
 326 }
 327
 328 static int
 329 purge_old(struct dentry *parent, struct dentry *child)
 330 {
 331         int status;
 332
 333         if (nfs4_has_reclaimed_state(child->d_name.name))
 334                 return 0;
 335
 336         status = nfsd4_clear_clid_dir(parent, child);
 337         if (status)
 338                 printk("failed to remove client recovery directory %s\n",
 339                                 child->d_name.name);
 340         /* Keep trying, success or failure: */
 341         return 0;
 342 }
 343
 344 void
 345 nfsd4_recdir_purge_old(void) {
 346         int status;
 347
 348         if (!rec_dir_init)
 349                 return;
 350         status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
 351         if (status == 0)
 352                 nfsd4_sync_rec_dir();
 353         if (status)
 354                 printk("nfsd4: failed to purge old clients from recovery"
 355                         " directory %s\n", rec_dir.dentry->d_name.name);
 356         return;
 357 }
 358
 359 static int
 360 load_recdir(struct dentry *parent, struct dentry *child)
 361 {
 362         if (child->d_name.len != HEXDIR_LEN - 1) {
 363                 printk("nfsd4: illegal name %s in recovery directory\n",
 364                                 child->d_name.name);
 365                 /* Keep trying; maybe the others are OK: */
 366                 return 0;
 367         }
 368         nfs4_client_to_reclaim(child->d_name.name);
 369         return 0;
 370 }
 371
 372 int
 373 nfsd4_recdir_load(void) {
 374         int status;
 375
 376         status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
 377         if (status)
 378                 printk("nfsd4: failed loading clients from recovery"
 379                         " directory %s\n", rec_dir.dentry->d_name.name);
 380         return status;
 381 }
 382
 383 /*
 384  * Hold reference to the recovery directory.
 385  */
 386
 387 void
 388 nfsd4_init_recdir(char *rec_dirname)
 389 {
 390         uid_t                   uid = 0;
 391         gid_t                   gid = 0;
 392         int                     status;
 393
 394         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 395                         rec_dirname);
 396
 397         BUG_ON(rec_dir_init);
 398
 399         nfs4_save_user(&uid, &gid);
 400
 401         status = path_lookup(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
 402                         &rec_dir);
 403         if (status)
 404                 printk("NFSD: unable to find recovery directory %s\n",
 405                                 rec_dirname);
 406
 407         if (!status)
 408                 rec_dir_init = 1;
 409         nfs4_reset_user(uid, gid);
 410 }
 411
 412 void
 413 nfsd4_shutdown_recdir(void)
 414 {
 415         if (!rec_dir_init)
 416                 return;
 417         rec_dir_init = 0;
 418         path_release(&rec_dir);
 419 }