SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/nfsd/nfsfh.c

   1 /*
   2  * linux/fs/nfsd/nfsfh.c
   3  *
   4  * NFS server file handle treatment.
   5  *
   6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7  * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
   8  * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
   9  * ... and again Southern-Winter 2001 to support export_operations
  10  */
  11
  12 #include <linux/slab.h>
  13 #include <linux/fs.h>
  14 #include <linux/unistd.h>
  15 #include <linux/string.h>
  16 #include <linux/stat.h>
  17 #include <linux/dcache.h>
  18 #include <linux/exportfs.h>
  19 #include <linux/mount.h>
  20
  21 #include <linux/sunrpc/clnt.h>
  22 #include <linux/sunrpc/svc.h>
  23 #include <linux/nfsd/nfsd.h>
  24
  25 #define NFSDDBG_FACILITY                NFSDDBG_FH
  26
  27
  28 static int nfsd_nr_verified;
  29 static int nfsd_nr_put;
  30
  31 /*
  32  * our acceptability function.
  33  * if NOSUBTREECHECK, accept anything
  34  * if not, require that we can walk up to exp->ex_dentry
  35  * doing some checks on the 'x' bits
  36  */
  37 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  38 {
  39         struct svc_export *exp = expv;
  40         int rv;
  41         struct dentry *tdentry;
  42         struct dentry *parent;
  43
  44         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  45                 return 1;
  46
  47         tdentry = dget(dentry);
  48         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
  49                 /* make sure parents give x permission to user */
  50                 int err;
  51                 parent = dget_parent(tdentry);
  52                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  53                 if (err < 0) {
  54                         dput(parent);
  55                         break;
  56                 }
  57                 dput(tdentry);
  58                 tdentry = parent;
  59         }
  60         if (tdentry != exp->ex_dentry)
  61                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  62         rv = (tdentry == exp->ex_dentry);
  63         dput(tdentry);
  64         return rv;
  65 }
  66
  67 /* Type check. The correct error return for type mismatches does not seem to be
  68  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  69  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  70  * the write call).
  71  */
  72 static inline __be32
  73 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  74 {
  75         /* Type can be negative when creating hardlinks - not to a dir */
  76         if (type > 0 && (mode & S_IFMT) != type) {
  77                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  78                         return nfserr_symlink;
  79                 else if (type == S_IFDIR)
  80                         return nfserr_notdir;
  81                 else if ((mode & S_IFMT) == S_IFDIR)
  82                         return nfserr_isdir;
  83                 else
  84                         return nfserr_inval;
  85         }
  86         if (type < 0 && (mode & S_IFMT) == -type) {
  87                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  88                         return nfserr_symlink;
  89                 else if (type == -S_IFDIR)
  90                         return nfserr_isdir;
  91                 else
  92                         return nfserr_notdir;
  93         }
  94         return 0;
  95 }
  96
  97 /*
  98  * Perform sanity checks on the dentry in a client's file handle.
  99  *
 100  * Note that the file handle dentry may need to be freed even after
 101  * an error return.
 102  *
 103  * This is only called at the start of an nfsproc call, so fhp points to
 104  * a svc_fh which is all 0 except for the over-the-wire file handle.
 105  */
 106 __be32
 107 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 108 {
 109         struct knfsd_fh *fh = &fhp->fh_handle;
 110         struct svc_export *exp = NULL;
 111         struct dentry   *dentry;
 112         __be32          error = 0;
 113
 114         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 115
 116         if (!fhp->fh_dentry) {
 117                 __u32 *datap=NULL;
 118                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 119                 int fileid_type;
 120                 int data_left = fh->fh_size/4;
 121
 122                 error = nfserr_stale;
 123                 if (rqstp->rq_vers > 2)
 124                         error = nfserr_badhandle;
 125                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 126                         return nfserr_nofilehandle;
 127
 128                 if (fh->fh_version == 1) {
 129                         int len;
 130                         datap = fh->fh_auth;
 131                         if (--data_left<0) goto out;
 132                         switch (fh->fh_auth_type) {
 133                         case 0: break;
 134                         default: goto out;
 135                         }
 136                         len = key_len(fh->fh_fsid_type) / 4;
 137                         if (len == 0) goto out;
 138                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 139                                 /* deprecated, convert to type 3 */
 140                                 len = key_len(FSID_ENCODE_DEV)/4;
 141                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 142                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 143                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 144                         }
 145                         if ((data_left -= len)<0) goto out;
 146                         exp = rqst_exp_find(rqstp, fh->fh_fsid_type, datap);
 147                         datap += len;
 148                 } else {
 149                         dev_t xdev;
 150                         ino_t xino;
 151                         if (fh->fh_size != NFS_FHSIZE)
 152                                 goto out;
 153                         /* assume old filehandle format */
 154                         xdev = old_decode_dev(fh->ofh_xdev);
 155                         xino = u32_to_ino_t(fh->ofh_xino);
 156                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 157                         exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 158                 }
 159
 160                 error = nfserr_stale;
 161                 if (PTR_ERR(exp) == -ENOENT)
 162                         goto out;
 163
 164                 if (IS_ERR(exp)) {
 165                         error = nfserrno(PTR_ERR(exp));
 166                         goto out;
 167                 }
 168
 169                 /* Check if the request originated from a secure port. */
 170                 error = nfserr_perm;
 171                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 172                         char buf[RPC_MAX_ADDRBUFLEN];
 173                         printk(KERN_WARNING
 174                                "nfsd: request from insecure port %s!\n",
 175                                svc_print_addr(rqstp, buf, sizeof(buf)));
 176                         goto out;
 177                 }
 178
 179                 /* Set user creds for this exportpoint */
 180                 error = nfserrno(nfsd_setuser(rqstp, exp));
 181                 if (error)
 182                         goto out;
 183
 184                 /*
 185                  * Look up the dentry using the NFS file handle.
 186                  */
 187                 error = nfserr_stale;
 188                 if (rqstp->rq_vers > 2)
 189                         error = nfserr_badhandle;
 190
 191                 if (fh->fh_version != 1) {
 192                         tfh[0] = fh->ofh_ino;
 193                         tfh[1] = fh->ofh_generation;
 194                         tfh[2] = fh->ofh_dirino;
 195                         datap = tfh;
 196                         data_left = 3;
 197                         if (fh->ofh_dirino == 0)
 198                                 fileid_type = 1;
 199                         else
 200                                 fileid_type = 2;
 201                 } else
 202                         fileid_type = fh->fh_fileid_type;
 203
 204                 if (fileid_type == 0)
 205                         dentry = dget(exp->ex_dentry);
 206                 else {
 207                         dentry = exportfs_decode_fh(exp->ex_mnt, datap,
 208                                         data_left, fileid_type,
 209                                         nfsd_acceptable, exp);
 210                 }
 211                 if (dentry == NULL)
 212                         goto out;
 213                 if (IS_ERR(dentry)) {
 214                         if (PTR_ERR(dentry) != -EINVAL)
 215                                 error = nfserrno(PTR_ERR(dentry));
 216                         goto out;
 217                 }
 218
 219                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 220                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 221                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 222                                dentry->d_parent->d_name.name, dentry->d_name.name);
 223                 }
 224
 225                 fhp->fh_dentry = dentry;
 226                 fhp->fh_export = exp;
 227                 nfsd_nr_verified++;
 228         } else {
 229                 /* just rechecking permissions
 230                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 231                  */
 232                 dprintk("nfsd: fh_verify - just checking\n");
 233                 dentry = fhp->fh_dentry;
 234                 exp = fhp->fh_export;
 235                 /* Set user creds for this exportpoint; necessary even
 236                  * in the "just checking" case because this may be a
 237                  * filehandle that was created by fh_compose, and that
 238                  * is about to be used in another nfsv4 compound
 239                  * operation */
 240                 error = nfserrno(nfsd_setuser(rqstp, exp));
 241                 if (error)
 242                         goto out;
 243         }
 244         cache_get(&exp->h);
 245
 246
 247         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 248         if (error)
 249                 goto out;
 250
 251         /* Finally, check access permissions. */
 252         error = nfsd_permission(exp, dentry, access);
 253
 254         if (error) {
 255                 dprintk("fh_verify: %s/%s permission failure, "
 256                         "acc=%x, error=%d\n",
 257                         dentry->d_parent->d_name.name,
 258                         dentry->d_name.name,
 259                         access, ntohl(error));
 260         }
 261 out:
 262         if (exp && !IS_ERR(exp))
 263                 exp_put(exp);
 264         if (error == nfserr_stale)
 265                 nfsdstats.fh_stale++;
 266         return error;
 267 }
 268
 269
 270 /*
 271  * Compose a file handle for an NFS reply.
 272  *
 273  * Note that when first composed, the dentry may not yet have
 274  * an inode.  In this case a call to fh_update should be made
 275  * before the fh goes out on the wire ...
 276  */
 277 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 278                              __u32 *datap, int *maxsize)
 279 {
 280         if (dentry == exp->ex_dentry) {
 281                 *maxsize = 0;
 282                 return 0;
 283         }
 284
 285         return exportfs_encode_fh(dentry, datap, maxsize,
 286                           !(exp->ex_flags & NFSEXP_NOSUBTREECHECK));
 287 }
 288
 289 /*
 290  * for composing old style file handles
 291  */
 292 static inline void _fh_update_old(struct dentry *dentry,
 293                                   struct svc_export *exp,
 294                                   struct knfsd_fh *fh)
 295 {
 296         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 297         fh->ofh_generation = dentry->d_inode->i_generation;
 298         if (S_ISDIR(dentry->d_inode->i_mode) ||
 299             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 300                 fh->ofh_dirino = 0;
 301 }
 302
 303 __be32
 304 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 305            struct svc_fh *ref_fh)
 306 {
 307         /* ref_fh is a reference file handle.
 308          * if it is non-null and for the same filesystem, then we should compose
 309          * a filehandle which is of the same version, where possible.
 310          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 311          * Then create a 32byte filehandle using nfs_fhbase_old
 312          *
 313          */
 314
 315         u8 version;
 316         u8 fsid_type = 0;
 317         struct inode * inode = dentry->d_inode;
 318         struct dentry *parent = dentry->d_parent;
 319         __u32 *datap;
 320         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 321         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 322
 323         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 324                 MAJOR(ex_dev), MINOR(ex_dev),
 325                 (long) exp->ex_dentry->d_inode->i_ino,
 326                 parent->d_name.name, dentry->d_name.name,
 327                 (inode ? inode->i_ino : 0));
 328
 329         /* Choose filehandle version and fsid type based on
 330          * the reference filehandle (if it is in the same export)
 331          * or the export options.
 332          */
 333  retry:
 334         version = 1;
 335         if (ref_fh && ref_fh->fh_export == exp) {
 336                 version = ref_fh->fh_handle.fh_version;
 337                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 338
 339                 if (ref_fh == fhp)
 340                         fh_put(ref_fh);
 341                 ref_fh = NULL;
 342
 343                 switch (version) {
 344                 case 0xca:
 345                         fsid_type = FSID_DEV;
 346                         break;
 347                 case 1:
 348                         break;
 349                 default:
 350                         goto retry;
 351                 }
 352
 353                 /* Need to check that this type works for this
 354                  * export point.  As the fsid -> filesystem mapping
 355                  * was guided by user-space, there is no guarantee
 356                  * that the filesystem actually supports that fsid
 357                  * type. If it doesn't we loop around again without
 358                  * ref_fh set.
 359                  */
 360                 switch(fsid_type) {
 361                 case FSID_DEV:
 362                         if (!old_valid_dev(ex_dev))
 363                                 goto retry;
 364                         /* FALL THROUGH */
 365                 case FSID_MAJOR_MINOR:
 366                 case FSID_ENCODE_DEV:
 367                         if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
 368                               & FS_REQUIRES_DEV))
 369                                 goto retry;
 370                         break;
 371                 case FSID_NUM:
 372                         if (! (exp->ex_flags & NFSEXP_FSID))
 373                                 goto retry;
 374                         break;
 375                 case FSID_UUID8:
 376                 case FSID_UUID16:
 377                         if (!root_export)
 378                                 goto retry;
 379                         /* fall through */
 380                 case FSID_UUID4_INUM:
 381                 case FSID_UUID16_INUM:
 382                         if (exp->ex_uuid == NULL)
 383                                 goto retry;
 384                         break;
 385                 }
 386         } else if (exp->ex_uuid) {
 387                 if (fhp->fh_maxsize >= 64) {
 388                         if (root_export)
 389                                 fsid_type = FSID_UUID16;
 390                         else
 391                                 fsid_type = FSID_UUID16_INUM;
 392                 } else {
 393                         if (root_export)
 394                                 fsid_type = FSID_UUID8;
 395                         else
 396                                 fsid_type = FSID_UUID4_INUM;
 397                 }
 398         } else if (exp->ex_flags & NFSEXP_FSID)
 399                 fsid_type = FSID_NUM;
 400         else if (!old_valid_dev(ex_dev))
 401                 /* for newer device numbers, we must use a newer fsid format */
 402                 fsid_type = FSID_ENCODE_DEV;
 403         else
 404                 fsid_type = FSID_DEV;
 405
 406         if (ref_fh == fhp)
 407                 fh_put(ref_fh);
 408
 409         if (fhp->fh_locked || fhp->fh_dentry) {
 410                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 411                        parent->d_name.name, dentry->d_name.name);
 412         }
 413         if (fhp->fh_maxsize < NFS_FHSIZE)
 414                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 415                        fhp->fh_maxsize,
 416                        parent->d_name.name, dentry->d_name.name);
 417
 418         fhp->fh_dentry = dget(dentry); /* our internal copy */
 419         fhp->fh_export = exp;
 420         cache_get(&exp->h);
 421
 422         if (version == 0xca) {
 423                 /* old style filehandle please */
 424                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 425                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 426                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 427                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 428                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 429                 fhp->fh_handle.ofh_xino =
 430                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 431                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 432                 if (inode)
 433                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 434         } else {
 435                 int len;
 436                 fhp->fh_handle.fh_version = 1;
 437                 fhp->fh_handle.fh_auth_type = 0;
 438                 datap = fhp->fh_handle.fh_auth+0;
 439                 fhp->fh_handle.fh_fsid_type = fsid_type;
 440                 mk_fsid(fsid_type, datap, ex_dev,
 441                         exp->ex_dentry->d_inode->i_ino,
 442                         exp->ex_fsid, exp->ex_uuid);
 443
 444                 len = key_len(fsid_type);
 445                 datap += len/4;
 446                 fhp->fh_handle.fh_size = 4 + len;
 447
 448                 if (inode) {
 449                         int size = (fhp->fh_maxsize-len-4)/4;
 450                         fhp->fh_handle.fh_fileid_type =
 451                                 _fh_update(dentry, exp, datap, &size);
 452                         fhp->fh_handle.fh_size += size*4;
 453                 }
 454                 if (fhp->fh_handle.fh_fileid_type == 255)
 455                         return nfserr_opnotsupp;
 456         }
 457
 458         nfsd_nr_verified++;
 459         return 0;
 460 }
 461
 462 /*
 463  * Update file handle information after changing a dentry.
 464  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 465  */
 466 __be32
 467 fh_update(struct svc_fh *fhp)
 468 {
 469         struct dentry *dentry;
 470         __u32 *datap;
 471
 472         if (!fhp->fh_dentry)
 473                 goto out_bad;
 474
 475         dentry = fhp->fh_dentry;
 476         if (!dentry->d_inode)
 477                 goto out_negative;
 478         if (fhp->fh_handle.fh_version != 1) {
 479                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 480         } else {
 481                 int size;
 482                 if (fhp->fh_handle.fh_fileid_type != 0)
 483                         goto out;
 484                 datap = fhp->fh_handle.fh_auth+
 485                         fhp->fh_handle.fh_size/4 -1;
 486                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 487                 fhp->fh_handle.fh_fileid_type =
 488                         _fh_update(dentry, fhp->fh_export, datap, &size);
 489                 fhp->fh_handle.fh_size += size*4;
 490                 if (fhp->fh_handle.fh_fileid_type == 255)
 491                         return nfserr_opnotsupp;
 492         }
 493 out:
 494         return 0;
 495
 496 out_bad:
 497         printk(KERN_ERR "fh_update: fh not verified!\n");
 498         goto out;
 499 out_negative:
 500         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 501                 dentry->d_parent->d_name.name, dentry->d_name.name);
 502         goto out;
 503 }
 504
 505 /*
 506  * Release a file handle.
 507  */
 508 void
 509 fh_put(struct svc_fh *fhp)
 510 {
 511         struct dentry * dentry = fhp->fh_dentry;
 512         struct svc_export * exp = fhp->fh_export;
 513         if (dentry) {
 514                 fh_unlock(fhp);
 515                 fhp->fh_dentry = NULL;
 516                 dput(dentry);
 517 #ifdef CONFIG_NFSD_V3
 518                 fhp->fh_pre_saved = 0;
 519                 fhp->fh_post_saved = 0;
 520 #endif
 521                 nfsd_nr_put++;
 522         }
 523         if (exp) {
 524                 cache_put(&exp->h, &svc_export_cache);
 525                 fhp->fh_export = NULL;
 526         }
 527         return;
 528 }
 529
 530 /*
 531  * Shorthand for dprintk()'s
 532  */
 533 char * SVCFH_fmt(struct svc_fh *fhp)
 534 {
 535         struct knfsd_fh *fh = &fhp->fh_handle;
 536
 537         static char buf[80];
 538         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 539                 fh->fh_size,
 540                 fh->fh_base.fh_pad[0],
 541                 fh->fh_base.fh_pad[1],
 542                 fh->fh_base.fh_pad[2],
 543                 fh->fh_base.fh_pad[3],
 544                 fh->fh_base.fh_pad[4],
 545                 fh->fh_base.fh_pad[5]);
 546         return buf;
 547 }
 548
 549 enum fsid_source fsid_source(struct svc_fh *fhp)
 550 {
 551         if (fhp->fh_handle.fh_version != 1)
 552                 return FSIDSOURCE_DEV;
 553         switch(fhp->fh_handle.fh_fsid_type) {
 554         case FSID_DEV:
 555         case FSID_ENCODE_DEV:
 556         case FSID_MAJOR_MINOR:
 557                 return FSIDSOURCE_DEV;
 558         case FSID_NUM:
 559                 return FSIDSOURCE_FSID;
 560         default:
 561                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 562                         return FSIDSOURCE_FSID;
 563                 else
 564                         return FSIDSOURCE_UUID;
 565         }
 566 }