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/namei.h>
  36 #include <linux/crypto.h>
  37 #include <linux/sched.h>
  38
  39 #include "nfsd.h"
  40 #include "state.h"
  41 #include "vfs.h"
  42
  43 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  44
  45 /* Globals */
  46 static struct path rec_dir;
  47 static int rec_dir_init = 0;
  48
  49 static int
  50 nfs4_save_creds(const struct cred **original_creds)
  51 {
  52         struct cred *new;
  53
  54         new = prepare_creds();
  55         if (!new)
  56                 return -ENOMEM;
  57
  58         new->fsuid = 0;
  59         new->fsgid = 0;
  60         *original_creds = override_creds(new);
  61         put_cred(new);
  62         return 0;
  63 }
  64
  65 static void
  66 nfs4_reset_creds(const struct cred *original)
  67 {
  68         revert_creds(original);
  69 }
  70
  71 static void
  72 md5_to_hex(char *out, char *md5)
  73 {
  74         int i;
  75
  76         for (i=0; i<16; i++) {
  77                 unsigned char c = md5[i];
  78
  79                 *out++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1);
  80                 *out++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1);
  81         }
  82         *out = '\0';
  83 }
  84
  85 __be32
  86 nfs4_make_rec_clidname(char *dname, struct xdr_netobj *clname)
  87 {
  88         struct xdr_netobj cksum;
  89         struct hash_desc desc;
  90         struct scatterlist sg;
  91         __be32 status = nfserr_resource;
  92
  93         dprintk("NFSD: nfs4_make_rec_clidname for %.*s\n",
  94                         clname->len, clname->data);
  95         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
  96         desc.tfm = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
  97         if (IS_ERR(desc.tfm))
  98                 goto out_no_tfm;
  99         cksum.len = crypto_hash_digestsize(desc.tfm);
 100         cksum.data = kmalloc(cksum.len, GFP_KERNEL);
 101         if (cksum.data == NULL)
 102                 goto out;
 103
 104         sg_init_one(&sg, clname->data, clname->len);
 105
 106         if (crypto_hash_digest(&desc, &sg, sg.length, cksum.data))
 107                 goto out;
 108
 109         md5_to_hex(dname, cksum.data);
 110
 111         status = nfs_ok;
 112 out:
 113         kfree(cksum.data);
 114         crypto_free_hash(desc.tfm);
 115 out_no_tfm:
 116         return status;
 117 }
 118
 119 static void
 120 nfsd4_sync_rec_dir(void)
 121 {
 122         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 123         nfsd_sync_dir(rec_dir.dentry);
 124         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 125 }
 126
 127 int
 128 nfsd4_create_clid_dir(struct nfs4_client *clp)
 129 {
 130         const struct cred *original_cred;
 131         char *dname = clp->cl_recdir;
 132         struct dentry *dentry;
 133         int status;
 134
 135         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 136
 137         if (!rec_dir_init || clp->cl_firststate)
 138                 return 0;
 139
 140         status = nfs4_save_creds(&original_cred);
 141         if (status < 0)
 142                 return status;
 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 = mnt_want_write(rec_dir.mnt);
 158         if (status)
 159                 goto out_put;
 160         status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
 161         mnt_drop_write(rec_dir.mnt);
 162 out_put:
 163         dput(dentry);
 164 out_unlock:
 165         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 166         if (status == 0) {
 167                 clp->cl_firststate = 1;
 168                 nfsd4_sync_rec_dir();
 169         }
 170         nfs4_reset_creds(original_cred);
 171         dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
 172         return status;
 173 }
 174
 175 typedef int (recdir_func)(struct dentry *, struct dentry *);
 176
 177 struct name_list {
 178         char name[HEXDIR_LEN];
 179         struct list_head list;
 180 };
 181
 182 static int
 183 nfsd4_build_namelist(void *arg, const char *name, int namlen,
 184                 loff_t offset, u64 ino, unsigned int d_type)
 185 {
 186         struct list_head *names = arg;
 187         struct name_list *entry;
 188
 189         if (namlen != HEXDIR_LEN - 1)
 190                 return 0;
 191         entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
 192         if (entry == NULL)
 193                 return -ENOMEM;
 194         memcpy(entry->name, name, HEXDIR_LEN - 1);
 195         entry->name[HEXDIR_LEN - 1] = '\0';
 196         list_add(&entry->list, names);
 197         return 0;
 198 }
 199
 200 static int
 201 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
 202 {
 203         const struct cred *original_cred;
 204         struct file *filp;
 205         LIST_HEAD(names);
 206         struct name_list *entry;
 207         struct dentry *dentry;
 208         int status;
 209
 210         if (!rec_dir_init)
 211                 return 0;
 212
 213         status = nfs4_save_creds(&original_cred);
 214         if (status < 0)
 215                 return status;
 216
 217         filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY,
 218                            current_cred());
 219         status = PTR_ERR(filp);
 220         if (IS_ERR(filp))
 221                 goto out;
 222         status = vfs_readdir(filp, nfsd4_build_namelist, &names);
 223         fput(filp);
 224         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 225         while (!list_empty(&names)) {
 226                 entry = list_entry(names.next, struct name_list, list);
 227
 228                 dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
 229                 if (IS_ERR(dentry)) {
 230                         status = PTR_ERR(dentry);
 231                         break;
 232                 }
 233                 status = f(dir, dentry);
 234                 dput(dentry);
 235                 if (status)
 236                         break;
 237                 list_del(&entry->list);
 238                 kfree(entry);
 239         }
 240         mutex_unlock(&dir->d_inode->i_mutex);
 241 out:
 242         while (!list_empty(&names)) {
 243                 entry = list_entry(names.next, struct name_list, list);
 244                 list_del(&entry->list);
 245                 kfree(entry);
 246         }
 247         nfs4_reset_creds(original_cred);
 248         return status;
 249 }
 250
 251 static int
 252 nfsd4_unlink_clid_dir(char *name, int namlen)
 253 {
 254         struct dentry *dentry;
 255         int status;
 256
 257         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 258
 259         mutex_lock_nested(&rec_dir.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 260         dentry = lookup_one_len(name, rec_dir.dentry, namlen);
 261         if (IS_ERR(dentry)) {
 262                 status = PTR_ERR(dentry);
 263                 goto out_unlock;
 264         }
 265         status = -ENOENT;
 266         if (!dentry->d_inode)
 267                 goto out;
 268         status = vfs_rmdir(rec_dir.dentry->d_inode, dentry);
 269 out:
 270         dput(dentry);
 271 out_unlock:
 272         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 273         return status;
 274 }
 275
 276 void
 277 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 278 {
 279         const struct cred *original_cred;
 280         int status;
 281
 282         if (!rec_dir_init || !clp->cl_firststate)
 283                 return;
 284
 285         status = mnt_want_write(rec_dir.mnt);
 286         if (status)
 287                 goto out;
 288         clp->cl_firststate = 0;
 289
 290         status = nfs4_save_creds(&original_cred);
 291         if (status < 0)
 292                 goto out;
 293
 294         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 295         nfs4_reset_creds(original_cred);
 296         if (status == 0)
 297                 nfsd4_sync_rec_dir();
 298         mnt_drop_write(rec_dir.mnt);
 299 out:
 300         if (status)
 301                 printk("NFSD: Failed to remove expired client state directory"
 302                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 303         return;
 304 }
 305
 306 static int
 307 purge_old(struct dentry *parent, struct dentry *child)
 308 {
 309         int status;
 310
 311         /* note: we currently use this path only for minorversion 0 */
 312         if (nfs4_has_reclaimed_state(child->d_name.name, false))
 313                 return 0;
 314
 315         status = vfs_rmdir(parent->d_inode, child);
 316         if (status)
 317                 printk("failed to remove client recovery directory %s\n",
 318                                 child->d_name.name);
 319         /* Keep trying, success or failure: */
 320         return 0;
 321 }
 322
 323 void
 324 nfsd4_recdir_purge_old(void) {
 325         int status;
 326
 327         if (!rec_dir_init)
 328                 return;
 329         status = mnt_want_write(rec_dir.mnt);
 330         if (status)
 331                 goto out;
 332         status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
 333         if (status == 0)
 334                 nfsd4_sync_rec_dir();
 335         mnt_drop_write(rec_dir.mnt);
 336 out:
 337         if (status)
 338                 printk("nfsd4: failed to purge old clients from recovery"
 339                         " directory %s\n", rec_dir.dentry->d_name.name);
 340 }
 341
 342 static int
 343 load_recdir(struct dentry *parent, struct dentry *child)
 344 {
 345         if (child->d_name.len != HEXDIR_LEN - 1) {
 346                 printk("nfsd4: illegal name %s in recovery directory\n",
 347                                 child->d_name.name);
 348                 /* Keep trying; maybe the others are OK: */
 349                 return 0;
 350         }
 351         nfs4_client_to_reclaim(child->d_name.name);
 352         return 0;
 353 }
 354
 355 int
 356 nfsd4_recdir_load(void) {
 357         int status;
 358
 359         status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
 360         if (status)
 361                 printk("nfsd4: failed loading clients from recovery"
 362                         " directory %s\n", rec_dir.dentry->d_name.name);
 363         return status;
 364 }
 365
 366 /*
 367  * Hold reference to the recovery directory.
 368  */
 369
 370 void
 371 nfsd4_init_recdir(char *rec_dirname)
 372 {
 373         const struct cred *original_cred;
 374         int status;
 375
 376         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 377                         rec_dirname);
 378
 379         BUG_ON(rec_dir_init);
 380
 381         status = nfs4_save_creds(&original_cred);
 382         if (status < 0) {
 383                 printk("NFSD: Unable to change credentials to find recovery"
 384                        " directory: error %d\n",
 385                        status);
 386                 return;
 387         }
 388
 389         status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
 390                         &rec_dir);
 391         if (status)
 392                 printk("NFSD: unable to find recovery directory %s\n",
 393                                 rec_dirname);
 394
 395         if (!status)
 396                 rec_dir_init = 1;
 397         nfs4_reset_creds(original_cred);
 398 }
 399
 400 void
 401 nfsd4_shutdown_recdir(void)
 402 {
 403         if (!rec_dir_init)
 404                 return;
 405         rec_dir_init = 0;
 406         path_put(&rec_dir);
 407 }