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   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_client == NULL)
 124                         goto out;
 125                 if (rqstp->rq_vers > 2)
 126                         error = nfserr_badhandle;
 127                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 128                         return nfserr_nofilehandle;
 129
 130                 if (fh->fh_version == 1) {
 131                         int len;
 132                         datap = fh->fh_auth;
 133                         if (--data_left<0) goto out;
 134                         switch (fh->fh_auth_type) {
 135                         case 0: break;
 136                         default: goto out;
 137                         }
 138                         len = key_len(fh->fh_fsid_type) / 4;
 139                         if (len == 0) goto out;
 140                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 141                                 /* deprecated, convert to type 3 */
 142                                 len = key_len(FSID_ENCODE_DEV)/4;
 143                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 144                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 145                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 146                         }
 147                         if ((data_left -= len)<0) goto out;
 148                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
 149                         datap += len;
 150                 } else {
 151                         dev_t xdev;
 152                         ino_t xino;
 153                         if (fh->fh_size != NFS_FHSIZE)
 154                                 goto out;
 155                         /* assume old filehandle format */
 156                         xdev = old_decode_dev(fh->ofh_xdev);
 157                         xino = u32_to_ino_t(fh->ofh_xino);
 158                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 159                         exp = exp_find(rqstp->rq_client, FSID_DEV, tfh,
 160                                        &rqstp->rq_chandle);
 161                 }
 162
 163                 error = nfserr_stale;
 164                 if (PTR_ERR(exp) == -ENOENT)
 165                         goto out;
 166
 167                 if (IS_ERR(exp)) {
 168                         error = nfserrno(PTR_ERR(exp));
 169                         goto out;
 170                 }
 171
 172                 /* Check if the request originated from a secure port. */
 173                 error = nfserr_perm;
 174                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 175                         char buf[RPC_MAX_ADDRBUFLEN];
 176                         printk(KERN_WARNING
 177                                "nfsd: request from insecure port %s!\n",
 178                                svc_print_addr(rqstp, buf, sizeof(buf)));
 179                         goto out;
 180                 }
 181
 182                 /* Set user creds for this exportpoint */
 183                 error = nfserrno(nfsd_setuser(rqstp, exp));
 184                 if (error)
 185                         goto out;
 186
 187                 /*
 188                  * Look up the dentry using the NFS file handle.
 189                  */
 190                 error = nfserr_stale;
 191                 if (rqstp->rq_vers > 2)
 192                         error = nfserr_badhandle;
 193
 194                 if (fh->fh_version != 1) {
 195                         tfh[0] = fh->ofh_ino;
 196                         tfh[1] = fh->ofh_generation;
 197                         tfh[2] = fh->ofh_dirino;
 198                         datap = tfh;
 199                         data_left = 3;
 200                         if (fh->ofh_dirino == 0)
 201                                 fileid_type = 1;
 202                         else
 203                                 fileid_type = 2;
 204                 } else
 205                         fileid_type = fh->fh_fileid_type;
 206
 207                 if (fileid_type == 0)
 208                         dentry = dget(exp->ex_dentry);
 209                 else {
 210                         dentry = exportfs_decode_fh(exp->ex_mnt, datap,
 211                                         data_left, fileid_type,
 212                                         nfsd_acceptable, exp);
 213                 }
 214                 if (dentry == NULL)
 215                         goto out;
 216                 if (IS_ERR(dentry)) {
 217                         if (PTR_ERR(dentry) != -EINVAL)
 218                                 error = nfserrno(PTR_ERR(dentry));
 219                         goto out;
 220                 }
 221
 222                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 223                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 224                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 225                                dentry->d_parent->d_name.name, dentry->d_name.name);
 226                 }
 227
 228                 fhp->fh_dentry = dentry;
 229                 fhp->fh_export = exp;
 230                 nfsd_nr_verified++;
 231         } else {
 232                 /* just rechecking permissions
 233                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 234                  */
 235                 dprintk("nfsd: fh_verify - just checking\n");
 236                 dentry = fhp->fh_dentry;
 237                 exp = fhp->fh_export;
 238                 /* Set user creds for this exportpoint; necessary even
 239                  * in the "just checking" case because this may be a
 240                  * filehandle that was created by fh_compose, and that
 241                  * is about to be used in another nfsv4 compound
 242                  * operation */
 243                 error = nfserrno(nfsd_setuser(rqstp, exp));
 244                 if (error)
 245                         goto out;
 246         }
 247         cache_get(&exp->h);
 248
 249
 250         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 251         if (error)
 252                 goto out;
 253
 254         /* Finally, check access permissions. */
 255         error = nfsd_permission(exp, dentry, access);
 256
 257         if (error) {
 258                 dprintk("fh_verify: %s/%s permission failure, "
 259                         "acc=%x, error=%d\n",
 260                         dentry->d_parent->d_name.name,
 261                         dentry->d_name.name,
 262                         access, ntohl(error));
 263         }
 264 out:
 265         if (exp && !IS_ERR(exp))
 266                 exp_put(exp);
 267         if (error == nfserr_stale)
 268                 nfsdstats.fh_stale++;
 269         return error;
 270 }
 271
 272
 273 /*
 274  * Compose a file handle for an NFS reply.
 275  *
 276  * Note that when first composed, the dentry may not yet have
 277  * an inode.  In this case a call to fh_update should be made
 278  * before the fh goes out on the wire ...
 279  */
 280 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 281                              __u32 *datap, int *maxsize)
 282 {
 283         if (dentry == exp->ex_dentry) {
 284                 *maxsize = 0;
 285                 return 0;
 286         }
 287
 288         return exportfs_encode_fh(dentry, datap, maxsize,
 289                           !(exp->ex_flags & NFSEXP_NOSUBTREECHECK));
 290 }
 291
 292 /*
 293  * for composing old style file handles
 294  */
 295 static inline void _fh_update_old(struct dentry *dentry,
 296                                   struct svc_export *exp,
 297                                   struct knfsd_fh *fh)
 298 {
 299         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 300         fh->ofh_generation = dentry->d_inode->i_generation;
 301         if (S_ISDIR(dentry->d_inode->i_mode) ||
 302             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 303                 fh->ofh_dirino = 0;
 304 }
 305
 306 __be32
 307 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 308            struct svc_fh *ref_fh)
 309 {
 310         /* ref_fh is a reference file handle.
 311          * if it is non-null and for the same filesystem, then we should compose
 312          * a filehandle which is of the same version, where possible.
 313          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 314          * Then create a 32byte filehandle using nfs_fhbase_old
 315          *
 316          */
 317
 318         u8 version;
 319         u8 fsid_type = 0;
 320         struct inode * inode = dentry->d_inode;
 321         struct dentry *parent = dentry->d_parent;
 322         __u32 *datap;
 323         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 324         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 325
 326         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 327                 MAJOR(ex_dev), MINOR(ex_dev),
 328                 (long) exp->ex_dentry->d_inode->i_ino,
 329                 parent->d_name.name, dentry->d_name.name,
 330                 (inode ? inode->i_ino : 0));
 331
 332         /* Choose filehandle version and fsid type based on
 333          * the reference filehandle (if it is in the same export)
 334          * or the export options.
 335          */
 336  retry:
 337         version = 1;
 338         if (ref_fh && ref_fh->fh_export == exp) {
 339                 version = ref_fh->fh_handle.fh_version;
 340                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 341
 342                 if (ref_fh == fhp)
 343                         fh_put(ref_fh);
 344                 ref_fh = NULL;
 345
 346                 switch (version) {
 347                 case 0xca:
 348                         fsid_type = FSID_DEV;
 349                         break;
 350                 case 1:
 351                         break;
 352                 default:
 353                         goto retry;
 354                 }
 355
 356                 /* Need to check that this type works for this
 357                  * export point.  As the fsid -> filesystem mapping
 358                  * was guided by user-space, there is no guarantee
 359                  * that the filesystem actually supports that fsid
 360                  * type. If it doesn't we loop around again without
 361                  * ref_fh set.
 362                  */
 363                 switch(fsid_type) {
 364                 case FSID_DEV:
 365                         if (!old_valid_dev(ex_dev))
 366                                 goto retry;
 367                         /* FALL THROUGH */
 368                 case FSID_MAJOR_MINOR:
 369                 case FSID_ENCODE_DEV:
 370                         if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
 371                               & FS_REQUIRES_DEV))
 372                                 goto retry;
 373                         break;
 374                 case FSID_NUM:
 375                         if (! (exp->ex_flags & NFSEXP_FSID))
 376                                 goto retry;
 377                         break;
 378                 case FSID_UUID8:
 379                 case FSID_UUID16:
 380                         if (!root_export)
 381                                 goto retry;
 382                         /* fall through */
 383                 case FSID_UUID4_INUM:
 384                 case FSID_UUID16_INUM:
 385                         if (exp->ex_uuid == NULL)
 386                                 goto retry;
 387                         break;
 388                 }
 389         } else if (exp->ex_uuid) {
 390                 if (fhp->fh_maxsize >= 64) {
 391                         if (root_export)
 392                                 fsid_type = FSID_UUID16;
 393                         else
 394                                 fsid_type = FSID_UUID16_INUM;
 395                 } else {
 396                         if (root_export)
 397                                 fsid_type = FSID_UUID8;
 398                         else
 399                                 fsid_type = FSID_UUID4_INUM;
 400                 }
 401         } else if (exp->ex_flags & NFSEXP_FSID)
 402                 fsid_type = FSID_NUM;
 403         else if (!old_valid_dev(ex_dev))
 404                 /* for newer device numbers, we must use a newer fsid format */
 405                 fsid_type = FSID_ENCODE_DEV;
 406         else
 407                 fsid_type = FSID_DEV;
 408
 409         if (ref_fh == fhp)
 410                 fh_put(ref_fh);
 411
 412         if (fhp->fh_locked || fhp->fh_dentry) {
 413                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 414                        parent->d_name.name, dentry->d_name.name);
 415         }
 416         if (fhp->fh_maxsize < NFS_FHSIZE)
 417                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 418                        fhp->fh_maxsize,
 419                        parent->d_name.name, dentry->d_name.name);
 420
 421         fhp->fh_dentry = dget(dentry); /* our internal copy */
 422         fhp->fh_export = exp;
 423         cache_get(&exp->h);
 424
 425         if (version == 0xca) {
 426                 /* old style filehandle please */
 427                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 428                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 429                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 430                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 431                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 432                 fhp->fh_handle.ofh_xino =
 433                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 434                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 435                 if (inode)
 436                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 437         } else {
 438                 int len;
 439                 fhp->fh_handle.fh_version = 1;
 440                 fhp->fh_handle.fh_auth_type = 0;
 441                 datap = fhp->fh_handle.fh_auth+0;
 442                 fhp->fh_handle.fh_fsid_type = fsid_type;
 443                 mk_fsid(fsid_type, datap, ex_dev,
 444                         exp->ex_dentry->d_inode->i_ino,
 445                         exp->ex_fsid, exp->ex_uuid);
 446
 447                 len = key_len(fsid_type);
 448                 datap += len/4;
 449                 fhp->fh_handle.fh_size = 4 + len;
 450
 451                 if (inode) {
 452                         int size = (fhp->fh_maxsize-len-4)/4;
 453                         fhp->fh_handle.fh_fileid_type =
 454                                 _fh_update(dentry, exp, datap, &size);
 455                         fhp->fh_handle.fh_size += size*4;
 456                 }
 457                 if (fhp->fh_handle.fh_fileid_type == 255)
 458                         return nfserr_opnotsupp;
 459         }
 460
 461         nfsd_nr_verified++;
 462         return 0;
 463 }
 464
 465 /*
 466  * Update file handle information after changing a dentry.
 467  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 468  */
 469 __be32
 470 fh_update(struct svc_fh *fhp)
 471 {
 472         struct dentry *dentry;
 473         __u32 *datap;
 474
 475         if (!fhp->fh_dentry)
 476                 goto out_bad;
 477
 478         dentry = fhp->fh_dentry;
 479         if (!dentry->d_inode)
 480                 goto out_negative;
 481         if (fhp->fh_handle.fh_version != 1) {
 482                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 483         } else {
 484                 int size;
 485                 if (fhp->fh_handle.fh_fileid_type != 0)
 486                         goto out;
 487                 datap = fhp->fh_handle.fh_auth+
 488                         fhp->fh_handle.fh_size/4 -1;
 489                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 490                 fhp->fh_handle.fh_fileid_type =
 491                         _fh_update(dentry, fhp->fh_export, datap, &size);
 492                 fhp->fh_handle.fh_size += size*4;
 493                 if (fhp->fh_handle.fh_fileid_type == 255)
 494                         return nfserr_opnotsupp;
 495         }
 496 out:
 497         return 0;
 498
 499 out_bad:
 500         printk(KERN_ERR "fh_update: fh not verified!\n");
 501         goto out;
 502 out_negative:
 503         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 504                 dentry->d_parent->d_name.name, dentry->d_name.name);
 505         goto out;
 506 }
 507
 508 /*
 509  * Release a file handle.
 510  */
 511 void
 512 fh_put(struct svc_fh *fhp)
 513 {
 514         struct dentry * dentry = fhp->fh_dentry;
 515         struct svc_export * exp = fhp->fh_export;
 516         if (dentry) {
 517                 fh_unlock(fhp);
 518                 fhp->fh_dentry = NULL;
 519                 dput(dentry);
 520 #ifdef CONFIG_NFSD_V3
 521                 fhp->fh_pre_saved = 0;
 522                 fhp->fh_post_saved = 0;
 523 #endif
 524                 nfsd_nr_put++;
 525         }
 526         if (exp) {
 527                 cache_put(&exp->h, &svc_export_cache);
 528                 fhp->fh_export = NULL;
 529         }
 530         return;
 531 }
 532
 533 /*
 534  * Shorthand for dprintk()'s
 535  */
 536 char * SVCFH_fmt(struct svc_fh *fhp)
 537 {
 538         struct knfsd_fh *fh = &fhp->fh_handle;
 539
 540         static char buf[80];
 541         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 542                 fh->fh_size,
 543                 fh->fh_base.fh_pad[0],
 544                 fh->fh_base.fh_pad[1],
 545                 fh->fh_base.fh_pad[2],
 546                 fh->fh_base.fh_pad[3],
 547                 fh->fh_base.fh_pad[4],
 548                 fh->fh_base.fh_pad[5]);
 549         return buf;
 550 }
 551
 552 enum fsid_source fsid_source(struct svc_fh *fhp)
 553 {
 554         if (fhp->fh_handle.fh_version != 1)
 555                 return FSIDSOURCE_DEV;
 556         switch(fhp->fh_handle.fh_fsid_type) {
 557         case FSID_DEV:
 558         case FSID_ENCODE_DEV:
 559         case FSID_MAJOR_MINOR:
 560                 return FSIDSOURCE_DEV;
 561         case FSID_NUM:
 562                 return FSIDSOURCE_FSID;
 563         default:
 564                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 565                         return FSIDSOURCE_FSID;
 566                 else
 567                         return FSIDSOURCE_UUID;
 568         }
 569 }