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 file *rec_file;
  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 int
 120 nfsd4_create_clid_dir(struct nfs4_client *clp)
 121 {
 122         const struct cred *original_cred;
 123         char *dname = clp->cl_recdir;
 124         struct dentry *dir, *dentry;
 125         int status;
 126
 127         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 128
 129         if (!rec_file || clp->cl_firststate)
 130                 return 0;
 131
 132         status = nfs4_save_creds(&original_cred);
 133         if (status < 0)
 134                 return status;
 135
 136         dir = rec_file->f_path.dentry;
 137         /* lock the parent */
 138         mutex_lock(&dir->d_inode->i_mutex);
 139
 140         dentry = lookup_one_len(dname, dir, HEXDIR_LEN-1);
 141         if (IS_ERR(dentry)) {
 142                 status = PTR_ERR(dentry);
 143                 goto out_unlock;
 144         }
 145         status = -EEXIST;
 146         if (dentry->d_inode) {
 147                 dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
 148                 goto out_put;
 149         }
 150         status = mnt_want_write(rec_file->f_path.mnt);
 151         if (status)
 152                 goto out_put;
 153         status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU);
 154         mnt_drop_write(rec_file->f_path.mnt);
 155 out_put:
 156         dput(dentry);
 157 out_unlock:
 158         mutex_unlock(&dir->d_inode->i_mutex);
 159         if (status == 0) {
 160                 clp->cl_firststate = 1;
 161                 vfs_fsync(rec_file, 0);
 162         }
 163         nfs4_reset_creds(original_cred);
 164         dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
 165         return status;
 166 }
 167
 168 typedef int (recdir_func)(struct dentry *, struct dentry *);
 169
 170 struct name_list {
 171         char name[HEXDIR_LEN];
 172         struct list_head list;
 173 };
 174
 175 static int
 176 nfsd4_build_namelist(void *arg, const char *name, int namlen,
 177                 loff_t offset, u64 ino, unsigned int d_type)
 178 {
 179         struct list_head *names = arg;
 180         struct name_list *entry;
 181
 182         if (namlen != HEXDIR_LEN - 1)
 183                 return 0;
 184         entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
 185         if (entry == NULL)
 186                 return -ENOMEM;
 187         memcpy(entry->name, name, HEXDIR_LEN - 1);
 188         entry->name[HEXDIR_LEN - 1] = '\0';
 189         list_add(&entry->list, names);
 190         return 0;
 191 }
 192
 193 static int
 194 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
 195 {
 196         const struct cred *original_cred;
 197         struct file *filp;
 198         LIST_HEAD(names);
 199         struct name_list *entry;
 200         struct dentry *dentry;
 201         int status;
 202
 203         if (!rec_file)
 204                 return 0;
 205
 206         status = nfs4_save_creds(&original_cred);
 207         if (status < 0)
 208                 return status;
 209
 210         filp = dentry_open(dget(dir), mntget(rec_file->f_path.mnt), O_RDONLY,
 211                            current_cred());
 212         status = PTR_ERR(filp);
 213         if (IS_ERR(filp))
 214                 goto out;
 215         status = vfs_readdir(filp, nfsd4_build_namelist, &names);
 216         fput(filp);
 217         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 218         while (!list_empty(&names)) {
 219                 entry = list_entry(names.next, struct name_list, list);
 220
 221                 dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
 222                 if (IS_ERR(dentry)) {
 223                         status = PTR_ERR(dentry);
 224                         break;
 225                 }
 226                 status = f(dir, dentry);
 227                 dput(dentry);
 228                 if (status)
 229                         break;
 230                 list_del(&entry->list);
 231                 kfree(entry);
 232         }
 233         mutex_unlock(&dir->d_inode->i_mutex);
 234 out:
 235         while (!list_empty(&names)) {
 236                 entry = list_entry(names.next, struct name_list, list);
 237                 list_del(&entry->list);
 238                 kfree(entry);
 239         }
 240         nfs4_reset_creds(original_cred);
 241         return status;
 242 }
 243
 244 static int
 245 nfsd4_unlink_clid_dir(char *name, int namlen)
 246 {
 247         struct dentry *dir, *dentry;
 248         int status;
 249
 250         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 251
 252         dir = rec_file->f_path.dentry;
 253         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 254         dentry = lookup_one_len(name, dir, namlen);
 255         if (IS_ERR(dentry)) {
 256                 status = PTR_ERR(dentry);
 257                 goto out_unlock;
 258         }
 259         status = -ENOENT;
 260         if (!dentry->d_inode)
 261                 goto out;
 262         status = vfs_rmdir(dir->d_inode, dentry);
 263 out:
 264         dput(dentry);
 265 out_unlock:
 266         mutex_unlock(&dir->d_inode->i_mutex);
 267         return status;
 268 }
 269
 270 void
 271 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 272 {
 273         const struct cred *original_cred;
 274         int status;
 275
 276         if (!rec_file || !clp->cl_firststate)
 277                 return;
 278
 279         status = mnt_want_write(rec_file->f_path.mnt);
 280         if (status)
 281                 goto out;
 282         clp->cl_firststate = 0;
 283
 284         status = nfs4_save_creds(&original_cred);
 285         if (status < 0)
 286                 goto out;
 287
 288         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 289         nfs4_reset_creds(original_cred);
 290         if (status == 0)
 291                 vfs_fsync(rec_file, 0);
 292         mnt_drop_write(rec_file->f_path.mnt);
 293 out:
 294         if (status)
 295                 printk("NFSD: Failed to remove expired client state directory"
 296                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 297         return;
 298 }
 299
 300 static int
 301 purge_old(struct dentry *parent, struct dentry *child)
 302 {
 303         int status;
 304
 305         /* note: we currently use this path only for minorversion 0 */
 306         if (nfs4_has_reclaimed_state(child->d_name.name, false))
 307                 return 0;
 308
 309         status = vfs_rmdir(parent->d_inode, child);
 310         if (status)
 311                 printk("failed to remove client recovery directory %s\n",
 312                                 child->d_name.name);
 313         /* Keep trying, success or failure: */
 314         return 0;
 315 }
 316
 317 void
 318 nfsd4_recdir_purge_old(void) {
 319         int status;
 320
 321         if (!rec_file)
 322                 return;
 323         status = mnt_want_write(rec_file->f_path.mnt);
 324         if (status)
 325                 goto out;
 326         status = nfsd4_list_rec_dir(rec_file->f_path.dentry, purge_old);
 327         if (status == 0)
 328                 vfs_fsync(rec_file, 0);
 329         mnt_drop_write(rec_file->f_path.mnt);
 330 out:
 331         if (status)
 332                 printk("nfsd4: failed to purge old clients from recovery"
 333                         " directory %s\n", rec_file->f_path.dentry->d_name.name);
 334 }
 335
 336 static int
 337 load_recdir(struct dentry *parent, struct dentry *child)
 338 {
 339         if (child->d_name.len != HEXDIR_LEN - 1) {
 340                 printk("nfsd4: illegal name %s in recovery directory\n",
 341                                 child->d_name.name);
 342                 /* Keep trying; maybe the others are OK: */
 343                 return 0;
 344         }
 345         nfs4_client_to_reclaim(child->d_name.name);
 346         return 0;
 347 }
 348
 349 int
 350 nfsd4_recdir_load(void) {
 351         int status;
 352
 353         if (!rec_file)
 354                 return 0;
 355
 356         status = nfsd4_list_rec_dir(rec_file->f_path.dentry, load_recdir);
 357         if (status)
 358                 printk("nfsd4: failed loading clients from recovery"
 359                         " directory %s\n", rec_file->f_path.dentry->d_name.name);
 360         return status;
 361 }
 362
 363 /*
 364  * Hold reference to the recovery directory.
 365  */
 366
 367 void
 368 nfsd4_init_recdir(char *rec_dirname)
 369 {
 370         const struct cred *original_cred;
 371         int status;
 372
 373         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 374                         rec_dirname);
 375
 376         BUG_ON(rec_file);
 377
 378         status = nfs4_save_creds(&original_cred);
 379         if (status < 0) {
 380                 printk("NFSD: Unable to change credentials to find recovery"
 381                        " directory: error %d\n",
 382                        status);
 383                 return;
 384         }
 385
 386         rec_file = filp_open(rec_dirname, O_RDONLY | O_DIRECTORY, 0);
 387         if (IS_ERR(rec_file)) {
 388                 printk("NFSD: unable to find recovery directory %s\n",
 389                                 rec_dirname);
 390                 rec_file = NULL;
 391         }
 392
 393         nfs4_reset_creds(original_cred);
 394 }
 395
 396 void
 397 nfsd4_shutdown_recdir(void)
 398 {
 399         if (!rec_file)
 400                 return;
 401         fput(rec_file);
 402         rec_file = NULL;
 403 }