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