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 void
  58 nfs4_save_user(uid_t *saveuid, gid_t *savegid)
  59 {
  60         *saveuid = current->fsuid;
  61         *savegid = current->fsgid;
  62         current->fsuid = 0;
  63         current->fsgid = 0;
  64 }
  65
  66 static void
  67 nfs4_reset_user(uid_t saveuid, gid_t savegid)
  68 {
  69         current->fsuid = saveuid;
  70         current->fsgid = savegid;
  71 }
  72
  73 static void
  74 md5_to_hex(char *out, char *md5)
  75 {
  76         int i;
  77
  78         for (i=0; i<16; i++) {
  79                 unsigned char c = md5[i];
  80
  81                 *out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
  82                 *out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
  83         }
  84         *out = '\0';
  85 }
  86
  87 __be32
  88 nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
  89 {
  90         struct xdr_netobj cksum;
  91         struct hash_desc desc;
  92         struct scatterlist sg;
  93         __be32 status = nfserr_resource;
  94
  95         dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
  96                         clname->len, clname->data);
  97         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
  98         desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
  99         if (IS_ERR(desc.tfm))
 100                 goto out_no_tfm;
 101         cksum.len = crypto_hash_digestsize(desc.tfm);
 102         cksum.data = kmalloc(cksum.len, GFP_KERNEL);
 103         if (cksum.data == NULL)
 104                 goto out;
 105
 106         sg_init_one(&sg, clname->data, clname->len);
 107
 108         if (crypto_hash_digest(&desc, &sg, sg.length, cksum.data))
 109                 goto out;
 110
 111         md5_to_hex(dname, cksum.data);
 112
 113         kfree(cksum.data);
 114         status = nfs_ok;
 115 out:
 116         crypto_free_hash(desc.tfm);
 117 out_no_tfm:
 118         return status;
 119 }
 120
 121 static void
 122 nfsd4_sync_rec_dir(void)
 123 {
 124         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 125         nfsd_sync_dir(rec_dir.dentry);
 126         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 127 }
 128
 129 int
 130 nfsd4_create_clid_dir(struct nfs4_client *clp)
 131 {
 132         char *dname = clp->cl_recdir;
 133         struct dentry *dentry;
 134         uid_t uid;
 135         gid_t gid;
 136         int status;
 137
 138         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 139
 140         if (!rec_dir_init || clp->cl_firststate)
 141                 return 0;
 142
 143         nfs4_save_user(&uid, &gid);
 144
 145         /* lock the parent */
 146         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 147
 148         dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
 149         if (IS_ERR(dentry)) {
 150                 status = PTR_ERR(dentry);
 151                 goto out_unlock;
 152         }
 153         status = -EEXIST;
 154         if (dentry->d_inode) {
 155                 dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
 156                 goto out_put;
 157         }
 158         status = mnt_want_write(rec_dir.mnt);
 159         if (status)
 160                 goto out_put;
 161         status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
 162         mnt_drop_write(rec_dir.mnt);
 163 out_put:
 164         dput(dentry);
 165 out_unlock:
 166         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 167         if (status == 0) {
 168                 clp->cl_firststate = 1;
 169                 nfsd4_sync_rec_dir();
 170         }
 171         nfs4_reset_user(uid, gid);
 172         dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
 173         return status;
 174 }
 175
 176 typedef int (recdir_func)(struct dentry *, struct dentry *);
 177
 178 struct dentry_list {
 179         struct dentry *dentry;
 180         struct list_head list;
 181 };
 182
 183 struct dentry_list_arg {
 184         struct list_head dentries;
 185         struct dentry *parent;
 186 };
 187
 188 static int
 189 nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
 190                 loff_t offset, u64 ino, unsigned int d_type)
 191 {
 192         struct dentry_list_arg *dla = arg;
 193         struct list_head *dentries = &dla->dentries;
 194         struct dentry *parent = dla->parent;
 195         struct dentry *dentry;
 196         struct dentry_list *child;
 197
 198         if (name && isdotent(name, namlen))
 199                 return 0;
 200         dentry = lookup_one_len(name, parent, namlen);
 201         if (IS_ERR(dentry))
 202                 return PTR_ERR(dentry);
 203         child = kmalloc(sizeof(*child), GFP_KERNEL);
 204         if (child == NULL)
 205                 return -ENOMEM;
 206         child->dentry = dentry;
 207         list_add(&child->list, dentries);
 208         return 0;
 209 }
 210
 211 static int
 212 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
 213 {
 214         struct file *filp;
 215         struct dentry_list_arg dla = {
 216                 .parent = dir,
 217         };
 218         struct list_head *dentries = &dla.dentries;
 219         struct dentry_list *child;
 220         uid_t uid;
 221         gid_t gid;
 222         int status;
 223
 224         if (!rec_dir_init)
 225                 return 0;
 226
 227         nfs4_save_user(&uid, &gid);
 228         INIT_LIST_HEAD(dentries);
 229
 230         filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY);
 231         status = PTR_ERR(filp);
 232         if (IS_ERR(filp))
 233                 goto out;
 234         status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
 235         fput(filp);
 236         while (!list_empty(dentries)) {
 237                 child = list_entry(dentries->next, struct dentry_list, list);
 238                 status = f(dir, child->dentry);
 239                 if (status)
 240                         goto out;
 241                 list_del(&child->list);
 242                 dput(child->dentry);
 243                 kfree(child);
 244         }
 245 out:
 246         while (!list_empty(dentries)) {
 247                 child = list_entry(dentries->next, struct dentry_list, list);
 248                 list_del(&child->list);
 249                 dput(child->dentry);
 250                 kfree(child);
 251         }
 252         nfs4_reset_user(uid, gid);
 253         return status;
 254 }
 255
 256 static int
 257 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
 258 {
 259         int status;
 260
 261         if (!S_ISREG(dir->d_inode->i_mode)) {
 262                 printk("nfsd4: non-file found in client recovery directory\n");
 263                 return -EINVAL;
 264         }
 265         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 266         status = vfs_unlink(dir->d_inode, dentry);
 267         mutex_unlock(&dir->d_inode->i_mutex);
 268         return status;
 269 }
 270
 271 static int
 272 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
 273 {
 274         int status;
 275
 276         /* For now this directory should already be empty, but we empty it of
 277          * any regular files anyway, just in case the directory was created by
 278          * a kernel from the future.... */
 279         nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
 280         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 281         status = vfs_rmdir(dir->d_inode, dentry);
 282         mutex_unlock(&dir->d_inode->i_mutex);
 283         return status;
 284 }
 285
 286 static int
 287 nfsd4_unlink_clid_dir(char *name, int namlen)
 288 {
 289         struct dentry *dentry;
 290         int status;
 291
 292         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 293
 294         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 295         dentry = lookup_one_len(name, rec_dir.dentry, namlen);
 296         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 297         if (IS_ERR(dentry)) {
 298                 status = PTR_ERR(dentry);
 299                 return status;
 300         }
 301         status = -ENOENT;
 302         if (!dentry->d_inode)
 303                 goto out;
 304
 305         status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry);
 306 out:
 307         dput(dentry);
 308         return status;
 309 }
 310
 311 void
 312 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 313 {
 314         uid_t uid;
 315         gid_t gid;
 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         nfs4_save_user(&uid, &gid);
 326         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 327         nfs4_reset_user(uid, gid);
 328         if (status == 0)
 329                 nfsd4_sync_rec_dir();
 330         mnt_drop_write(rec_dir.mnt);
 331 out:
 332         if (status)
 333                 printk("NFSD: Failed to remove expired client state directory"
 334                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 335         return;
 336 }
 337
 338 static int
 339 purge_old(struct dentry *parent, struct dentry *child)
 340 {
 341         int status;
 342
 343         if (nfs4_has_reclaimed_state(child->d_name.name))
 344                 return 0;
 345
 346         status = nfsd4_clear_clid_dir(parent, child);
 347         if (status)
 348                 printk("failed to remove client recovery directory %s\n",
 349                                 child->d_name.name);
 350         /* Keep trying, success or failure: */
 351         return 0;
 352 }
 353
 354 void
 355 nfsd4_recdir_purge_old(void) {
 356         int status;
 357
 358         if (!rec_dir_init)
 359                 return;
 360         status = mnt_want_write(rec_dir.mnt);
 361         if (status)
 362                 goto out;
 363         status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
 364         if (status == 0)
 365                 nfsd4_sync_rec_dir();
 366         mnt_drop_write(rec_dir.mnt);
 367 out:
 368         if (status)
 369                 printk("nfsd4: failed to purge old clients from recovery"
 370                         " directory %s\n", rec_dir.dentry->d_name.name);
 371 }
 372
 373 static int
 374 load_recdir(struct dentry *parent, struct dentry *child)
 375 {
 376         if (child->d_name.len != HEXDIR_LEN - 1) {
 377                 printk("nfsd4: illegal name %s in recovery directory\n",
 378                                 child->d_name.name);
 379                 /* Keep trying; maybe the others are OK: */
 380                 return 0;
 381         }
 382         nfs4_client_to_reclaim(child->d_name.name);
 383         return 0;
 384 }
 385
 386 int
 387 nfsd4_recdir_load(void) {
 388         int status;
 389
 390         status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
 391         if (status)
 392                 printk("nfsd4: failed loading clients from recovery"
 393                         " directory %s\n", rec_dir.dentry->d_name.name);
 394         return status;
 395 }
 396
 397 /*
 398  * Hold reference to the recovery directory.
 399  */
 400
 401 void
 402 nfsd4_init_recdir(char *rec_dirname)
 403 {
 404         uid_t                   uid = 0;
 405         gid_t                   gid = 0;
 406         int                     status;
 407
 408         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 409                         rec_dirname);
 410
 411         BUG_ON(rec_dir_init);
 412
 413         nfs4_save_user(&uid, &gid);
 414
 415         status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
 416                         &rec_dir);
 417         if (status)
 418                 printk("NFSD: unable to find recovery directory %s\n",
 419                                 rec_dirname);
 420
 421         if (!status)
 422                 rec_dir_init = 1;
 423         nfs4_reset_user(uid, gid);
 424 }
 425
 426 void
 427 nfsd4_shutdown_recdir(void)
 428 {
 429         if (!rec_dir_init)
 430                 return;
 431         rec_dir_init = 0;
 432         path_put(&rec_dir);
 433 }