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/slab.h>
  36 #include <linux/namei.h>
  37 #include <linux/crypto.h>
  38 #include <linux/sched.h>
  39
  40 #include "nfsd.h"
  41 #include "state.h"
  42 #include "vfs.h"
  43
  44 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  45
  46 /* Globals */
  47 static struct path rec_dir;
  48 static int rec_dir_init = 0;
  49
  50 static int
  51 nfs4_save_creds(const struct cred **original_creds)
  52 {
  53         struct cred *new;
  54
  55         new = prepare_creds();
  56         if (!new)
  57                 return -ENOMEM;
  58
  59         new->fsuid = 0;
  60         new->fsgid = 0;
  61         *original_creds = override_creds(new);
  62         put_cred(new);
  63         return 0;
  64 }
  65
  66 static void
  67 nfs4_reset_creds(const struct cred *original)
  68 {
  69         revert_creds(original);
  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         status = nfs_ok;
 113 out:
 114         kfree(cksum.data);
 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         vfs_fsync(NULL, rec_dir.dentry, 0);
 124 }
 125
 126 int
 127 nfsd4_create_clid_dir(struct nfs4_client *clp)
 128 {
 129         const struct cred *original_cred;
 130         char *dname = clp->cl_recdir;
 131         struct dentry *dentry;
 132         int status;
 133
 134         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 135
 136         if (!rec_dir_init || clp->cl_firststate)
 137                 return 0;
 138
 139         status = nfs4_save_creds(&original_cred);
 140         if (status < 0)
 141                 return status;
 142
 143         /* lock the parent */
 144         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 145
 146         dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
 147         if (IS_ERR(dentry)) {
 148                 status = PTR_ERR(dentry);
 149                 goto out_unlock;
 150         }
 151         status = -EEXIST;
 152         if (dentry->d_inode) {
 153                 dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
 154                 goto out_put;
 155         }
 156         status = mnt_want_write(rec_dir.mnt);
 157         if (status)
 158                 goto out_put;
 159         status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
 160         mnt_drop_write(rec_dir.mnt);
 161 out_put:
 162         dput(dentry);
 163 out_unlock:
 164         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 165         if (status == 0) {
 166                 clp->cl_firststate = 1;
 167                 nfsd4_sync_rec_dir();
 168         }
 169         nfs4_reset_creds(original_cred);
 170         dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
 171         return status;
 172 }
 173
 174 typedef int (recdir_func)(struct dentry *, struct dentry *);
 175
 176 struct name_list {
 177         char name[HEXDIR_LEN];
 178         struct list_head list;
 179 };
 180
 181 static int
 182 nfsd4_build_namelist(void *arg, const char *name, int namlen,
 183                 loff_t offset, u64 ino, unsigned int d_type)
 184 {
 185         struct list_head *names = arg;
 186         struct name_list *entry;
 187
 188         if (namlen != HEXDIR_LEN - 1)
 189                 return 0;
 190         entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
 191         if (entry == NULL)
 192                 return -ENOMEM;
 193         memcpy(entry->name, name, HEXDIR_LEN - 1);
 194         entry->name[HEXDIR_LEN - 1] = '\0';
 195         list_add(&entry->list, names);
 196         return 0;
 197 }
 198
 199 static int
 200 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
 201 {
 202         const struct cred *original_cred;
 203         struct file *filp;
 204         LIST_HEAD(names);
 205         struct name_list *entry;
 206         struct dentry *dentry;
 207         int status;
 208
 209         if (!rec_dir_init)
 210                 return 0;
 211
 212         status = nfs4_save_creds(&original_cred);
 213         if (status < 0)
 214                 return status;
 215
 216         filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY,
 217                            current_cred());
 218         status = PTR_ERR(filp);
 219         if (IS_ERR(filp))
 220                 goto out;
 221         status = vfs_readdir(filp, nfsd4_build_namelist, &names);
 222         fput(filp);
 223         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 224         while (!list_empty(&names)) {
 225                 entry = list_entry(names.next, struct name_list, list);
 226
 227                 dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
 228                 if (IS_ERR(dentry)) {
 229                         status = PTR_ERR(dentry);
 230                         break;
 231                 }
 232                 status = f(dir, dentry);
 233                 dput(dentry);
 234                 if (status)
 235                         break;
 236                 list_del(&entry->list);
 237                 kfree(entry);
 238         }
 239         mutex_unlock(&dir->d_inode->i_mutex);
 240 out:
 241         while (!list_empty(&names)) {
 242                 entry = list_entry(names.next, struct name_list, list);
 243                 list_del(&entry->list);
 244                 kfree(entry);
 245         }
 246         nfs4_reset_creds(original_cred);
 247         return status;
 248 }
 249
 250 static int
 251 nfsd4_unlink_clid_dir(char *name, int namlen)
 252 {
 253         struct dentry *dentry;
 254         int status;
 255
 256         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 257
 258         mutex_lock_nested(&rec_dir.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 259         dentry = lookup_one_len(name, rec_dir.dentry, namlen);
 260         if (IS_ERR(dentry)) {
 261                 status = PTR_ERR(dentry);
 262                 goto out_unlock;
 263         }
 264         status = -ENOENT;
 265         if (!dentry->d_inode)
 266                 goto out;
 267         status = vfs_rmdir(rec_dir.dentry->d_inode, dentry);
 268 out:
 269         dput(dentry);
 270 out_unlock:
 271         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 272         return status;
 273 }
 274
 275 void
 276 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 277 {
 278         const struct cred *original_cred;
 279         int status;
 280
 281         if (!rec_dir_init || !clp->cl_firststate)
 282                 return;
 283
 284         status = mnt_want_write(rec_dir.mnt);
 285         if (status)
 286                 goto out;
 287         clp->cl_firststate = 0;
 288
 289         status = nfs4_save_creds(&original_cred);
 290         if (status < 0)
 291                 goto out;
 292
 293         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 294         nfs4_reset_creds(original_cred);
 295         if (status == 0)
 296                 nfsd4_sync_rec_dir();
 297         mnt_drop_write(rec_dir.mnt);
 298 out:
 299         if (status)
 300                 printk("NFSD: Failed to remove expired client state directory"
 301                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 302         return;
 303 }
 304
 305 static int
 306 purge_old(struct dentry *parent, struct dentry *child)
 307 {
 308         int status;
 309
 310         /* note: we currently use this path only for minorversion 0 */
 311         if (nfs4_has_reclaimed_state(child->d_name.name, false))
 312                 return 0;
 313
 314         status = vfs_rmdir(parent->d_inode, child);
 315         if (status)
 316                 printk("failed to remove client recovery directory %s\n",
 317                                 child->d_name.name);
 318         /* Keep trying, success or failure: */
 319         return 0;
 320 }
 321
 322 void
 323 nfsd4_recdir_purge_old(void) {
 324         int status;
 325
 326         if (!rec_dir_init)
 327                 return;
 328         status = mnt_want_write(rec_dir.mnt);
 329         if (status)
 330                 goto out;
 331         status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
 332         if (status == 0)
 333                 nfsd4_sync_rec_dir();
 334         mnt_drop_write(rec_dir.mnt);
 335 out:
 336         if (status)
 337                 printk("nfsd4: failed to purge old clients from recovery"
 338                         " directory %s\n", rec_dir.dentry->d_name.name);
 339 }
 340
 341 static int
 342 load_recdir(struct dentry *parent, struct dentry *child)
 343 {
 344         if (child->d_name.len != HEXDIR_LEN - 1) {
 345                 printk("nfsd4: illegal name %s in recovery directory\n",
 346                                 child->d_name.name);
 347                 /* Keep trying; maybe the others are OK: */
 348                 return 0;
 349         }
 350         nfs4_client_to_reclaim(child->d_name.name);
 351         return 0;
 352 }
 353
 354 int
 355 nfsd4_recdir_load(void) {
 356         int status;
 357
 358         status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
 359         if (status)
 360                 printk("nfsd4: failed loading clients from recovery"
 361                         " directory %s\n", rec_dir.dentry->d_name.name);
 362         return status;
 363 }
 364
 365 /*
 366  * Hold reference to the recovery directory.
 367  */
 368
 369 void
 370 nfsd4_init_recdir(char *rec_dirname)
 371 {
 372         const struct cred *original_cred;
 373         int status;
 374
 375         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 376                         rec_dirname);
 377
 378         BUG_ON(rec_dir_init);
 379
 380         status = nfs4_save_creds(&original_cred);
 381         if (status < 0) {
 382                 printk("NFSD: Unable to change credentials to find recovery"
 383                        " directory: error %d\n",
 384                        status);
 385                 return;
 386         }
 387
 388         status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
 389                         &rec_dir);
 390         if (status)
 391                 printk("NFSD: unable to find recovery directory %s\n",
 392                                 rec_dirname);
 393
 394         if (!status)
 395                 rec_dir_init = 1;
 396         nfs4_reset_creds(original_cred);
 397 }
 398
 399 void
 400 nfsd4_shutdown_recdir(void)
 401 {
 402         if (!rec_dir_init)
 403                 return;
 404         rec_dir_init = 0;
 405         path_put(&rec_dir);
 406 }