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/mount.h>
  19
  20 #include <linux/sunrpc/clnt.h>
  21 #include <linux/sunrpc/svc.h>
  22 #include <linux/nfsd/nfsd.h>
  23
  24 #define NFSDDBG_FACILITY                NFSDDBG_FH
  25
  26
  27 static int nfsd_nr_verified;
  28 static int nfsd_nr_put;
  29
  30 extern struct export_operations export_op_default;
  31
  32 #define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
  33
  34 /*
  35  * our acceptability function.
  36  * if NOSUBTREECHECK, accept anything
  37  * if not, require that we can walk up to exp->ex_dentry
  38  * doing some checks on the 'x' bits
  39  */
  40 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  41 {
  42         struct svc_export *exp = expv;
  43         int rv;
  44         struct dentry *tdentry;
  45         struct dentry *parent;
  46
  47         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  48                 return 1;
  49
  50         tdentry = dget(dentry);
  51         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
  52                 /* make sure parents give x permission to user */
  53                 int err;
  54                 parent = dget_parent(tdentry);
  55                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  56                 if (err < 0) {
  57                         dput(parent);
  58                         break;
  59                 }
  60                 dput(tdentry);
  61                 tdentry = parent;
  62         }
  63         if (tdentry != exp->ex_dentry)
  64                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  65         rv = (tdentry == exp->ex_dentry);
  66         dput(tdentry);
  67         return rv;
  68 }
  69
  70 /* Type check. The correct error return for type mismatches does not seem to be
  71  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  72  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  73  * the write call).
  74  */
  75 static inline __be32
  76 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  77 {
  78         /* Type can be negative when creating hardlinks - not to a dir */
  79         if (type > 0 && (mode & S_IFMT) != type) {
  80                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  81                         return nfserr_symlink;
  82                 else if (type == S_IFDIR)
  83                         return nfserr_notdir;
  84                 else if ((mode & S_IFMT) == S_IFDIR)
  85                         return nfserr_isdir;
  86                 else
  87                         return nfserr_inval;
  88         }
  89         if (type < 0 && (mode & S_IFMT) == -type) {
  90                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  91                         return nfserr_symlink;
  92                 else if (type == -S_IFDIR)
  93                         return nfserr_isdir;
  94                 else
  95                         return nfserr_notdir;
  96         }
  97         return 0;
  98 }
  99
 100 /*
 101  * Perform sanity checks on the dentry in a client's file handle.
 102  *
 103  * Note that the file handle dentry may need to be freed even after
 104  * an error return.
 105  *
 106  * This is only called at the start of an nfsproc call, so fhp points to
 107  * a svc_fh which is all 0 except for the over-the-wire file handle.
 108  */
 109 __be32
 110 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 111 {
 112         struct knfsd_fh *fh = &fhp->fh_handle;
 113         struct svc_export *exp = NULL;
 114         struct dentry   *dentry;
 115         __be32          error = 0;
 116
 117         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 118
 119         if (!fhp->fh_dentry) {
 120                 __u32 *datap=NULL;
 121                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 122                 int fileid_type;
 123                 int data_left = fh->fh_size/4;
 124
 125                 error = nfserr_stale;
 126                 if (rqstp->rq_client == NULL)
 127                         goto out;
 128                 if (rqstp->rq_vers > 2)
 129                         error = nfserr_badhandle;
 130                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 131                         return nfserr_nofilehandle;
 132
 133                 if (fh->fh_version == 1) {
 134                         int len;
 135                         datap = fh->fh_auth;
 136                         if (--data_left<0) goto out;
 137                         switch (fh->fh_auth_type) {
 138                         case 0: break;
 139                         default: goto out;
 140                         }
 141                         len = key_len(fh->fh_fsid_type) / 4;
 142                         if (len == 0) goto out;
 143                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 144                                 /* deprecated, convert to type 3 */
 145                                 len = key_len(FSID_ENCODE_DEV)/4;
 146                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 147                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 148                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 149                         }
 150                         if ((data_left -= len)<0) goto out;
 151                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
 152                         datap += len;
 153                 } else {
 154                         dev_t xdev;
 155                         ino_t xino;
 156                         if (fh->fh_size != NFS_FHSIZE)
 157                                 goto out;
 158                         /* assume old filehandle format */
 159                         xdev = old_decode_dev(fh->ofh_xdev);
 160                         xino = u32_to_ino_t(fh->ofh_xino);
 161                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 162                         exp = exp_find(rqstp->rq_client, FSID_DEV, tfh,
 163                                        &rqstp->rq_chandle);
 164                 }
 165
 166                 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
 167                                 || PTR_ERR(exp) == -ETIMEDOUT)) {
 168                         error = nfserrno(PTR_ERR(exp));
 169                         goto out;
 170                 }
 171
 172                 error = nfserr_stale;
 173                 if (!exp || IS_ERR(exp))
 174                         goto out;
 175
 176                 /* Check if the request originated from a secure port. */
 177                 error = nfserr_perm;
 178                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 179                         char buf[RPC_MAX_ADDRBUFLEN];
 180                         printk(KERN_WARNING
 181                                "nfsd: request from insecure port %s!\n",
 182                                svc_print_addr(rqstp, buf, sizeof(buf)));
 183                         goto out;
 184                 }
 185
 186                 /* Set user creds for this exportpoint */
 187                 error = nfserrno(nfsd_setuser(rqstp, exp));
 188                 if (error)
 189                         goto out;
 190
 191                 /*
 192                  * Look up the dentry using the NFS file handle.
 193                  */
 194                 error = nfserr_stale;
 195                 if (rqstp->rq_vers > 2)
 196                         error = nfserr_badhandle;
 197
 198                 if (fh->fh_version != 1) {
 199                         tfh[0] = fh->ofh_ino;
 200                         tfh[1] = fh->ofh_generation;
 201                         tfh[2] = fh->ofh_dirino;
 202                         datap = tfh;
 203                         data_left = 3;
 204                         if (fh->ofh_dirino == 0)
 205                                 fileid_type = 1;
 206                         else
 207                                 fileid_type = 2;
 208                 } else
 209                         fileid_type = fh->fh_fileid_type;
 210
 211                 if (fileid_type == 0)
 212                         dentry = dget(exp->ex_dentry);
 213                 else {
 214                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 215                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 216                                                      datap, data_left,
 217                                                      fileid_type,
 218                                                      nfsd_acceptable, exp);
 219                 }
 220                 if (dentry == NULL)
 221                         goto out;
 222                 if (IS_ERR(dentry)) {
 223                         if (PTR_ERR(dentry) != -EINVAL)
 224                                 error = nfserrno(PTR_ERR(dentry));
 225                         goto out;
 226                 }
 227
 228                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 229                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 230                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 231                                dentry->d_parent->d_name.name, dentry->d_name.name);
 232                 }
 233
 234                 fhp->fh_dentry = dentry;
 235                 fhp->fh_export = exp;
 236                 nfsd_nr_verified++;
 237         } else {
 238                 /* just rechecking permissions
 239                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 240                  */
 241                 dprintk("nfsd: fh_verify - just checking\n");
 242                 dentry = fhp->fh_dentry;
 243                 exp = fhp->fh_export;
 244                 /* Set user creds for this exportpoint; necessary even
 245                  * in the "just checking" case because this may be a
 246                  * filehandle that was created by fh_compose, and that
 247                  * is about to be used in another nfsv4 compound
 248                  * operation */
 249                 error = nfserrno(nfsd_setuser(rqstp, exp));
 250                 if (error)
 251                         goto out;
 252         }
 253         cache_get(&exp->h);
 254
 255
 256         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 257         if (error)
 258                 goto out;
 259
 260         /* Finally, check access permissions. */
 261         error = nfsd_permission(exp, dentry, access);
 262
 263         if (error) {
 264                 dprintk("fh_verify: %s/%s permission failure, "
 265                         "acc=%x, error=%d\n",
 266                         dentry->d_parent->d_name.name,
 267                         dentry->d_name.name,
 268                         access, ntohl(error));
 269         }
 270 out:
 271         if (exp && !IS_ERR(exp))
 272                 exp_put(exp);
 273         if (error == nfserr_stale)
 274                 nfsdstats.fh_stale++;
 275         return error;
 276 }
 277
 278
 279 /*
 280  * Compose a file handle for an NFS reply.
 281  *
 282  * Note that when first composed, the dentry may not yet have
 283  * an inode.  In this case a call to fh_update should be made
 284  * before the fh goes out on the wire ...
 285  */
 286 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 287                              __u32 *datap, int *maxsize)
 288 {
 289         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 290
 291         if (dentry == exp->ex_dentry) {
 292                 *maxsize = 0;
 293                 return 0;
 294         }
 295
 296         return CALL(nop,encode_fh)(dentry, datap, maxsize,
 297                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
 298 }
 299
 300 /*
 301  * for composing old style file handles
 302  */
 303 static inline void _fh_update_old(struct dentry *dentry,
 304                                   struct svc_export *exp,
 305                                   struct knfsd_fh *fh)
 306 {
 307         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 308         fh->ofh_generation = dentry->d_inode->i_generation;
 309         if (S_ISDIR(dentry->d_inode->i_mode) ||
 310             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 311                 fh->ofh_dirino = 0;
 312 }
 313
 314 __be32
 315 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 316            struct svc_fh *ref_fh)
 317 {
 318         /* ref_fh is a reference file handle.
 319          * if it is non-null and for the same filesystem, then we should compose
 320          * a filehandle which is of the same version, where possible.
 321          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 322          * Then create a 32byte filehandle using nfs_fhbase_old
 323          *
 324          */
 325
 326         u8 version;
 327         u8 fsid_type = 0;
 328         struct inode * inode = dentry->d_inode;
 329         struct dentry *parent = dentry->d_parent;
 330         __u32 *datap;
 331         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 332         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 333
 334         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 335                 MAJOR(ex_dev), MINOR(ex_dev),
 336                 (long) exp->ex_dentry->d_inode->i_ino,
 337                 parent->d_name.name, dentry->d_name.name,
 338                 (inode ? inode->i_ino : 0));
 339
 340         /* Choose filehandle version and fsid type based on
 341          * the reference filehandle (if it is in the same export)
 342          * or the export options.
 343          */
 344  retry:
 345         version = 1;
 346         if (ref_fh && ref_fh->fh_export == exp) {
 347                 version = ref_fh->fh_handle.fh_version;
 348                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 349
 350                 if (ref_fh == fhp)
 351                         fh_put(ref_fh);
 352                 ref_fh = NULL;
 353
 354                 switch (version) {
 355                 case 0xca:
 356                         fsid_type = FSID_DEV;
 357                         break;
 358                 case 1:
 359                         break;
 360                 default:
 361                         goto retry;
 362                 }
 363
 364                 /* Need to check that this type works for this
 365                  * export point.  As the fsid -> filesystem mapping
 366                  * was guided by user-space, there is no guarantee
 367                  * that the filesystem actually supports that fsid
 368                  * type. If it doesn't we loop around again without
 369                  * ref_fh set.
 370                  */
 371                 switch(fsid_type) {
 372                 case FSID_DEV:
 373                         if (!old_valid_dev(ex_dev))
 374                                 goto retry;
 375                         /* FALL THROUGH */
 376                 case FSID_MAJOR_MINOR:
 377                 case FSID_ENCODE_DEV:
 378                         if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
 379                               & FS_REQUIRES_DEV))
 380                                 goto retry;
 381                         break;
 382                 case FSID_NUM:
 383                         if (! (exp->ex_flags & NFSEXP_FSID))
 384                                 goto retry;
 385                         break;
 386                 case FSID_UUID8:
 387                 case FSID_UUID16:
 388                         if (!root_export)
 389                                 goto retry;
 390                         /* fall through */
 391                 case FSID_UUID4_INUM:
 392                 case FSID_UUID16_INUM:
 393                         if (exp->ex_uuid == NULL)
 394                                 goto retry;
 395                         break;
 396                 }
 397         } else if (exp->ex_uuid) {
 398                 if (fhp->fh_maxsize >= 64) {
 399                         if (root_export)
 400                                 fsid_type = FSID_UUID16;
 401                         else
 402                                 fsid_type = FSID_UUID16_INUM;
 403                 } else {
 404                         if (root_export)
 405                                 fsid_type = FSID_UUID8;
 406                         else
 407                                 fsid_type = FSID_UUID4_INUM;
 408                 }
 409         } else if (exp->ex_flags & NFSEXP_FSID)
 410                 fsid_type = FSID_NUM;
 411         else if (!old_valid_dev(ex_dev))
 412                 /* for newer device numbers, we must use a newer fsid format */
 413                 fsid_type = FSID_ENCODE_DEV;
 414         else
 415                 fsid_type = FSID_DEV;
 416
 417         if (ref_fh == fhp)
 418                 fh_put(ref_fh);
 419
 420         if (fhp->fh_locked || fhp->fh_dentry) {
 421                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 422                        parent->d_name.name, dentry->d_name.name);
 423         }
 424         if (fhp->fh_maxsize < NFS_FHSIZE)
 425                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 426                        fhp->fh_maxsize,
 427                        parent->d_name.name, dentry->d_name.name);
 428
 429         fhp->fh_dentry = dget(dentry); /* our internal copy */
 430         fhp->fh_export = exp;
 431         cache_get(&exp->h);
 432
 433         if (version == 0xca) {
 434                 /* old style filehandle please */
 435                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 436                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 437                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 438                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 439                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 440                 fhp->fh_handle.ofh_xino =
 441                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 442                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 443                 if (inode)
 444                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 445         } else {
 446                 int len;
 447                 fhp->fh_handle.fh_version = 1;
 448                 fhp->fh_handle.fh_auth_type = 0;
 449                 datap = fhp->fh_handle.fh_auth+0;
 450                 fhp->fh_handle.fh_fsid_type = fsid_type;
 451                 mk_fsid(fsid_type, datap, ex_dev,
 452                         exp->ex_dentry->d_inode->i_ino,
 453                         exp->ex_fsid, exp->ex_uuid);
 454
 455                 len = key_len(fsid_type);
 456                 datap += len/4;
 457                 fhp->fh_handle.fh_size = 4 + len;
 458
 459                 if (inode) {
 460                         int size = (fhp->fh_maxsize-len-4)/4;
 461                         fhp->fh_handle.fh_fileid_type =
 462                                 _fh_update(dentry, exp, datap, &size);
 463                         fhp->fh_handle.fh_size += size*4;
 464                 }
 465                 if (fhp->fh_handle.fh_fileid_type == 255)
 466                         return nfserr_opnotsupp;
 467         }
 468
 469         nfsd_nr_verified++;
 470         return 0;
 471 }
 472
 473 /*
 474  * Update file handle information after changing a dentry.
 475  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 476  */
 477 __be32
 478 fh_update(struct svc_fh *fhp)
 479 {
 480         struct dentry *dentry;
 481         __u32 *datap;
 482
 483         if (!fhp->fh_dentry)
 484                 goto out_bad;
 485
 486         dentry = fhp->fh_dentry;
 487         if (!dentry->d_inode)
 488                 goto out_negative;
 489         if (fhp->fh_handle.fh_version != 1) {
 490                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 491         } else {
 492                 int size;
 493                 if (fhp->fh_handle.fh_fileid_type != 0)
 494                         goto out;
 495                 datap = fhp->fh_handle.fh_auth+
 496                         fhp->fh_handle.fh_size/4 -1;
 497                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 498                 fhp->fh_handle.fh_fileid_type =
 499                         _fh_update(dentry, fhp->fh_export, datap, &size);
 500                 fhp->fh_handle.fh_size += size*4;
 501                 if (fhp->fh_handle.fh_fileid_type == 255)
 502                         return nfserr_opnotsupp;
 503         }
 504 out:
 505         return 0;
 506
 507 out_bad:
 508         printk(KERN_ERR "fh_update: fh not verified!\n");
 509         goto out;
 510 out_negative:
 511         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 512                 dentry->d_parent->d_name.name, dentry->d_name.name);
 513         goto out;
 514 }
 515
 516 /*
 517  * Release a file handle.
 518  */
 519 void
 520 fh_put(struct svc_fh *fhp)
 521 {
 522         struct dentry * dentry = fhp->fh_dentry;
 523         struct svc_export * exp = fhp->fh_export;
 524         if (dentry) {
 525                 fh_unlock(fhp);
 526                 fhp->fh_dentry = NULL;
 527                 dput(dentry);
 528 #ifdef CONFIG_NFSD_V3
 529                 fhp->fh_pre_saved = 0;
 530                 fhp->fh_post_saved = 0;
 531 #endif
 532                 nfsd_nr_put++;
 533         }
 534         if (exp) {
 535                 cache_put(&exp->h, &svc_export_cache);
 536                 fhp->fh_export = NULL;
 537         }
 538         return;
 539 }
 540
 541 /*
 542  * Shorthand for dprintk()'s
 543  */
 544 char * SVCFH_fmt(struct svc_fh *fhp)
 545 {
 546         struct knfsd_fh *fh = &fhp->fh_handle;
 547
 548         static char buf[80];
 549         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 550                 fh->fh_size,
 551                 fh->fh_base.fh_pad[0],
 552                 fh->fh_base.fh_pad[1],
 553                 fh->fh_base.fh_pad[2],
 554                 fh->fh_base.fh_pad[3],
 555                 fh->fh_base.fh_pad[4],
 556                 fh->fh_base.fh_pad[5]);
 557         return buf;
 558 }
 559
 560 enum fsid_source fsid_source(struct svc_fh *fhp)
 561 {
 562         if (fhp->fh_handle.fh_version != 1)
 563                 return FSIDSOURCE_DEV;
 564         switch(fhp->fh_handle.fh_fsid_type) {
 565         case FSID_DEV:
 566         case FSID_ENCODE_DEV:
 567         case FSID_MAJOR_MINOR:
 568                 return FSIDSOURCE_DEV;
 569         case FSID_NUM:
 570                 return FSIDSOURCE_FSID;
 571         default:
 572                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 573                         return FSIDSOURCE_FSID;
 574                 else
 575                         return FSIDSOURCE_UUID;
 576         }
 577 }