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 <asm/scatterlist.h>
  47 #include <linux/crypto.h>
  48 #include <linux/sched.h>
  49
  50 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  51
  52 /* Globals */
  53 static struct nameidata rec_dir;
  54 static int rec_dir_init = 0;
  55
  56 static void
  57 nfs4_save_user(uid_t *saveuid, gid_t *savegid)
  58 {
  59         *saveuid = current->fsuid;
  60         *savegid = current->fsgid;
  61         current->fsuid = 0;
  62         current->fsgid = 0;
  63 }
  64
  65 static void
  66 nfs4_reset_user(uid_t saveuid, gid_t savegid)
  67 {
  68         current->fsuid = saveuid;
  69         current->fsgid = savegid;
  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[1];
  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[0].page = virt_to_page(clname->data);
 106         sg[0].offset = offset_in_page(clname->data);
 107         sg[0].length = clname->len;
 108
 109         if (crypto_hash_digest(&desc, sg, sg->length, cksum.data))
 110                 goto out;
 111
 112         md5_to_hex(dname, cksum.data);
 113
 114         kfree(cksum.data);
 115         status = nfs_ok;
 116 out:
 117         crypto_free_hash(desc.tfm);
 118 out_no_tfm:
 119         return status;
 120 }
 121
 122 static void
 123 nfsd4_sync_rec_dir(void)
 124 {
 125         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 126         nfsd_sync_dir(rec_dir.dentry);
 127         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 128 }
 129
 130 int
 131 nfsd4_create_clid_dir(struct nfs4_client *clp)
 132 {
 133         char *dname = clp->cl_recdir;
 134         struct dentry *dentry;
 135         uid_t uid;
 136         gid_t gid;
 137         int status;
 138
 139         dprintk("NFSD: nfsd4_create_clid_dir for \"%s\"\n", dname);
 140
 141         if (!rec_dir_init || clp->cl_firststate)
 142                 return 0;
 143
 144         nfs4_save_user(&uid, &gid);
 145
 146         /* lock the parent */
 147         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 148
 149         dentry = lookup_one_len(dname, rec_dir.dentry, HEXDIR_LEN-1);
 150         if (IS_ERR(dentry)) {
 151                 status = PTR_ERR(dentry);
 152                 goto out_unlock;
 153         }
 154         status = -EEXIST;
 155         if (dentry->d_inode) {
 156                 dprintk("NFSD: nfsd4_create_clid_dir: DIRECTORY EXISTS\n");
 157                 goto out_put;
 158         }
 159         status = vfs_mkdir(rec_dir.dentry->d_inode, dentry, S_IRWXU);
 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_user(uid, gid);
 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 dentry_list {
 176         struct dentry *dentry;
 177         struct list_head list;
 178 };
 179
 180 struct dentry_list_arg {
 181         struct list_head dentries;
 182         struct dentry *parent;
 183 };
 184
 185 static int
 186 nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
 187                 loff_t offset, u64 ino, unsigned int d_type)
 188 {
 189         struct dentry_list_arg *dla = arg;
 190         struct list_head *dentries = &dla->dentries;
 191         struct dentry *parent = dla->parent;
 192         struct dentry *dentry;
 193         struct dentry_list *child;
 194
 195         if (name && isdotent(name, namlen))
 196                 return 0;
 197         dentry = lookup_one_len(name, parent, namlen);
 198         if (IS_ERR(dentry))
 199                 return PTR_ERR(dentry);
 200         child = kmalloc(sizeof(*child), GFP_KERNEL);
 201         if (child == NULL)
 202                 return -ENOMEM;
 203         child->dentry = dentry;
 204         list_add(&child->list, dentries);
 205         return 0;
 206 }
 207
 208 static int
 209 nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
 210 {
 211         struct file *filp;
 212         struct dentry_list_arg dla = {
 213                 .parent = dir,
 214         };
 215         struct list_head *dentries = &dla.dentries;
 216         struct dentry_list *child;
 217         uid_t uid;
 218         gid_t gid;
 219         int status;
 220
 221         if (!rec_dir_init)
 222                 return 0;
 223
 224         nfs4_save_user(&uid, &gid);
 225
 226         filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY);
 227         status = PTR_ERR(filp);
 228         if (IS_ERR(filp))
 229                 goto out;
 230         INIT_LIST_HEAD(dentries);
 231         status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
 232         fput(filp);
 233         while (!list_empty(dentries)) {
 234                 child = list_entry(dentries->next, struct dentry_list, list);
 235                 status = f(dir, child->dentry);
 236                 if (status)
 237                         goto out;
 238                 list_del(&child->list);
 239                 dput(child->dentry);
 240                 kfree(child);
 241         }
 242 out:
 243         while (!list_empty(dentries)) {
 244                 child = list_entry(dentries->next, struct dentry_list, list);
 245                 list_del(&child->list);
 246                 dput(child->dentry);
 247                 kfree(child);
 248         }
 249         nfs4_reset_user(uid, gid);
 250         return status;
 251 }
 252
 253 static int
 254 nfsd4_remove_clid_file(struct dentry *dir, struct dentry *dentry)
 255 {
 256         int status;
 257
 258         if (!S_ISREG(dir->d_inode->i_mode)) {
 259                 printk("nfsd4: non-file found in client recovery directory\n");
 260                 return -EINVAL;
 261         }
 262         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 263         status = vfs_unlink(dir->d_inode, dentry);
 264         mutex_unlock(&dir->d_inode->i_mutex);
 265         return status;
 266 }
 267
 268 static int
 269 nfsd4_clear_clid_dir(struct dentry *dir, struct dentry *dentry)
 270 {
 271         int status;
 272
 273         /* For now this directory should already be empty, but we empty it of
 274          * any regular files anyway, just in case the directory was created by
 275          * a kernel from the future.... */
 276         nfsd4_list_rec_dir(dentry, nfsd4_remove_clid_file);
 277         mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
 278         status = vfs_rmdir(dir->d_inode, dentry);
 279         mutex_unlock(&dir->d_inode->i_mutex);
 280         return status;
 281 }
 282
 283 static int
 284 nfsd4_unlink_clid_dir(char *name, int namlen)
 285 {
 286         struct dentry *dentry;
 287         int status;
 288
 289         dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
 290
 291         mutex_lock(&rec_dir.dentry->d_inode->i_mutex);
 292         dentry = lookup_one_len(name, rec_dir.dentry, namlen);
 293         mutex_unlock(&rec_dir.dentry->d_inode->i_mutex);
 294         if (IS_ERR(dentry)) {
 295                 status = PTR_ERR(dentry);
 296                 return status;
 297         }
 298         status = -ENOENT;
 299         if (!dentry->d_inode)
 300                 goto out;
 301
 302         status = nfsd4_clear_clid_dir(rec_dir.dentry, dentry);
 303 out:
 304         dput(dentry);
 305         return status;
 306 }
 307
 308 void
 309 nfsd4_remove_clid_dir(struct nfs4_client *clp)
 310 {
 311         uid_t uid;
 312         gid_t gid;
 313         int status;
 314
 315         if (!rec_dir_init || !clp->cl_firststate)
 316                 return;
 317
 318         clp->cl_firststate = 0;
 319         nfs4_save_user(&uid, &gid);
 320         status = nfsd4_unlink_clid_dir(clp->cl_recdir, HEXDIR_LEN-1);
 321         nfs4_reset_user(uid, gid);
 322         if (status == 0)
 323                 nfsd4_sync_rec_dir();
 324         if (status)
 325                 printk("NFSD: Failed to remove expired client state directory"
 326                                 " %.*s\n", HEXDIR_LEN, clp->cl_recdir);
 327         return;
 328 }
 329
 330 static int
 331 purge_old(struct dentry *parent, struct dentry *child)
 332 {
 333         int status;
 334
 335         if (nfs4_has_reclaimed_state(child->d_name.name))
 336                 return 0;
 337
 338         status = nfsd4_clear_clid_dir(parent, child);
 339         if (status)
 340                 printk("failed to remove client recovery directory %s\n",
 341                                 child->d_name.name);
 342         /* Keep trying, success or failure: */
 343         return 0;
 344 }
 345
 346 void
 347 nfsd4_recdir_purge_old(void) {
 348         int status;
 349
 350         if (!rec_dir_init)
 351                 return;
 352         status = nfsd4_list_rec_dir(rec_dir.dentry, purge_old);
 353         if (status == 0)
 354                 nfsd4_sync_rec_dir();
 355         if (status)
 356                 printk("nfsd4: failed to purge old clients from recovery"
 357                         " directory %s\n", rec_dir.dentry->d_name.name);
 358         return;
 359 }
 360
 361 static int
 362 load_recdir(struct dentry *parent, struct dentry *child)
 363 {
 364         if (child->d_name.len != HEXDIR_LEN - 1) {
 365                 printk("nfsd4: illegal name %s in recovery directory\n",
 366                                 child->d_name.name);
 367                 /* Keep trying; maybe the others are OK: */
 368                 return 0;
 369         }
 370         nfs4_client_to_reclaim(child->d_name.name);
 371         return 0;
 372 }
 373
 374 int
 375 nfsd4_recdir_load(void) {
 376         int status;
 377
 378         status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
 379         if (status)
 380                 printk("nfsd4: failed loading clients from recovery"
 381                         " directory %s\n", rec_dir.dentry->d_name.name);
 382         return status;
 383 }
 384
 385 /*
 386  * Hold reference to the recovery directory.
 387  */
 388
 389 void
 390 nfsd4_init_recdir(char *rec_dirname)
 391 {
 392         uid_t                   uid = 0;
 393         gid_t                   gid = 0;
 394         int                     status;
 395
 396         printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
 397                         rec_dirname);
 398
 399         BUG_ON(rec_dir_init);
 400
 401         nfs4_save_user(&uid, &gid);
 402
 403         status = path_lookup(rec_dirname, LOOKUP_FOLLOW | LOOKUP_DIRECTORY,
 404                         &rec_dir);
 405         if (status)
 406                 printk("NFSD: unable to find recovery directory %s\n",
 407                                 rec_dirname);
 408
 409         if (!status)
 410                 rec_dir_init = 1;
 411         nfs4_reset_user(uid, gid);
 412 }
 413
 414 void
 415 nfsd4_shutdown_recdir(void)
 416 {
 417         if (!rec_dir_init)
 418                 return;
 419         rec_dir_init = 0;
 420         path_release(&rec_dir);
 421 }