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         vfs_fsync(NULL, rec_dir.dentry, 0);
 123 }
 124
 125 int
 126 nfsd4_create_clid_dir(struct nfs4_client *clp)
 127 {
 128         const struct cred *original_cred;
 129         char *dname = clp->cl_recdir;
 130         struct dentry *dentry;
 131         int status;
 132
 133         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 134
 135         if (!rec_dir_init || clp->cl_firststate)
 136                 return 0;
 137
 138         status = nfs4_save_creds(&original_cred);
 139         if (status < 0)
 140                 return status;
 141
 142         /* lock the parent */
 143         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 144
 145         dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
 146         if (IS_ERR(dentry)) {
 147                 status = PTR_ERR(dentry);
 148                 goto out_unlock;
 149         }
 150         status = -EEXIST;
 151         if (dentry->d_inode) {
 152                 dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
 153                 goto out_put;
 154         }
 155         status = mnt_want_write(rec_dir.mnt);
 156         if (status)
 157                 goto out_put;
 158         status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
 159         mnt_drop_write(rec_dir.mnt);
 160 out_put:
 161         dput(dentry);
 162 out_unlock:
 163         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 164         if (status == 0) {
 165                 clp->cl_firststate = 1;
 166                 nfsd4_sync_rec_dir();
 167         }
 168         nfs4_reset_creds(original_cred);
 169         dprintk("NFSD: nfsd4_create_clid_dir returns %d\n", status);
 170         return status;
 171 }
 172
 173 typedef int (recdir_func)(struct dentry *, struct dentry *);
 174
 175 struct name_list {
 176         char name[HEXDIR_LEN];
 177         struct list_head list;
 178 };
 179
 180 static int
 181 nfsd4_build_namelist(void *arg, const char *name, int namlen,
 182                 loff_t offset, u64 ino, unsigned int d_type)
 183 {
 184         struct list_head *names = arg;
 185         struct name_list *entry;
 186
 187         if (namlen != HEXDIR_LEN - 1)
 188                 return 0;
 189         entry = kmalloc(sizeof(struct name_list), GFP_KERNEL);
 190         if (entry == NULL)
 191                 return -ENOMEM;
 192         memcpy(entry->name, name, HEXDIR_LEN - 1);
 193         entry->name[HEXDIR_LEN - 1] = '\0';
 194         list_add(&entry->list, names);
 195         return 0;
 196 }
 197
 198 static int
 199 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
 200 {
 201         const struct cred *original_cred;
 202         struct file *filp;
 203         LIST_HEAD(names);
 204         struct name_list *entry;
 205         struct dentry *dentry;
 206         int status;
 207
 208         if (!rec_dir_init)
 209                 return 0;
 210
 211         status = nfs4_save_creds(&original_cred);
 212         if (status < 0)
 213                 return status;
 214
 215         filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY,
 216                            current_cred());
 217         status = PTR_ERR(filp);
 218         if (IS_ERR(filp))
 219                 goto out;
 220         status = vfs_readdir(filp, nfsd4_build_namelist, &names);
 221         fput(filp);
 222         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 223         while (!list_empty(&names)) {
 224                 entry = list_entry(names.next, struct name_list, list);
 225
 226                 dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
 227                 if (IS_ERR(dentry)) {
 228                         status = PTR_ERR(dentry);
 229                         break;
 230                 }
 231                 status = f(dir, dentry);
 232                 dput(dentry);
 233                 if (status)
 234                         break;
 235                 list_del(&entry->list);
 236                 kfree(entry);
 237         }
 238         mutex_unlock(&dir->d_inode->i_mutex);
 239 out:
 240         while (!list_empty(&names)) {
 241                 entry = list_entry(names.next, struct name_list, list);
 242                 list_del(&entry->list);
 243                 kfree(entry);
 244         }
 245         nfs4_reset_creds(original_cred);
 246         return status;
 247 }
 248
 249 static int
 250 nfsd4_unlink_clid_dir(char *name, int namlen)
 251 {
 252         struct dentry *dentry;
 253         int status;
 254
 255         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 256
 257         mutex_lock_nested(&rec_dir.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
 258         dentry = lookup_one_len(name, rec_dir.dentry, namlen);
 259         if (IS_ERR(dentry)) {
 260                 status = PTR_ERR(dentry);
 261                 goto out_unlock;
 262         }
 263         status = -ENOENT;
 264         if (!dentry->d_inode)
 265                 goto out;
 266         status = vfs_rmdir(rec_dir.dentry->d_inode, dentry);
 267 out:
 268         dput(dentry);
 269 out_unlock:
 270         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 271         return status;
 272 }
 273
 274 void
 275 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 276 {
 277         const struct cred *original_cred;
 278         int status;
 279
 280         if (!rec_dir_init || !clp->cl_firststate)
 281                 return;
 282
 283         status = mnt_want_write(rec_dir.mnt);
 284         if (status)
 285                 goto out;
 286         clp->cl_firststate = 0;
 287
 288         status = nfs4_save_creds(&original_cred);
 289         if (status < 0)
 290                 goto out;
 291
 292         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 293         nfs4_reset_creds(original_cred);
 294         if (status == 0)
 295                 nfsd4_sync_rec_dir();
 296         mnt_drop_write(rec_dir.mnt);
 297 out:
 298         if (status)
 299                 printk("NFSD: Failed to remove expired client state directory"
 300                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 301         return;
 302 }
 303
 304 static int
 305 purge_old(struct dentry *parent, struct dentry *child)
 306 {
 307         int status;
 308
 309         /* note: we currently use this path only for minorversion 0 */
 310         if (nfs4_has_reclaimed_state(child->d_name.name, false))
 311                 return 0;
 312
 313         status = vfs_rmdir(parent->d_inode, child);
 314         if (status)
 315                 printk("failed to remove client recovery directory %s\n",
 316                                 child->d_name.name);
 317         /* Keep trying, success or failure: */
 318         return 0;
 319 }
 320
 321 void
 322 nfsd4_recdir_purge_old(void) {
 323         int status;
 324
 325         if (!rec_dir_init)
 326                 return;
 327         status = mnt_want_write(rec_dir.mnt);
 328         if (status)
 329                 goto out;
 330         status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
 331         if (status == 0)
 332                 nfsd4_sync_rec_dir();
 333         mnt_drop_write(rec_dir.mnt);
 334 out:
 335         if (status)
 336                 printk("nfsd4: failed to purge old clients from recovery"
 337                         " directory %s\n", rec_dir.dentry->d_name.name);
 338 }
 339
 340 static int
 341 load_recdir(struct dentry *parent, struct dentry *child)
 342 {
 343         if (child->d_name.len != HEXDIR_LEN - 1) {
 344                 printk("nfsd4: illegal name %s in recovery directory\n",
 345                                 child->d_name.name);
 346                 /* Keep trying; maybe the others are OK: */
 347                 return 0;
 348         }
 349         nfs4_client_to_reclaim(child->d_name.name);
 350         return 0;
 351 }
 352
 353 int
 354 nfsd4_recdir_load(void) {
 355         int status;
 356
 357         status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
 358         if (status)
 359                 printk("nfsd4: failed loading clients from recovery"
 360                         " directory %s\n", rec_dir.dentry->d_name.name);
 361         return status;
 362 }
 363
 364 /*
 365  * Hold reference to the recovery directory.
 366  */
 367
 368 void
 369 nfsd4_init_recdir(char *rec_dirname)
 370 {
 371         const struct cred *original_cred;
 372         int status;
 373
 374         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 375                         rec_dirname);
 376
 377         BUG_ON(rec_dir_init);
 378
 379         status = nfs4_save_creds(&original_cred);
 380         if (status < 0) {
 381                 printk("NFSD: Unable to change credentials to find recovery"
 382                        " directory: error %d\n",
 383                        status);
 384                 return;
 385         }
 386
 387         status = kern_path(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
 388                         &rec_dir);
 389         if (status)
 390                 printk("NFSD: unable to find recovery directory %s\n",
 391                                 rec_dirname);
 392
 393         if (!status)
 394                 rec_dir_init = 1;
 395         nfs4_reset_creds(original_cred);
 396 }
 397
 398 void
 399 nfsd4_shutdown_recdir(void)
 400 {
 401         if (!rec_dir_init)
 402                 return;
 403         rec_dir_init = 0;
 404         path_put(&rec_dir);
 405 }