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/sunrpc/svcauth_gss.h>
  24 #include <linux/nfsd/nfsd.h>
  25
  26 #define NFSDDBG_FACILITY                NFSDDBG_FH
  27
  28
  29 static int nfsd_nr_verified;
  30 static int nfsd_nr_put;
  31
  32 /*
  33  * our acceptability function.
  34  * if NOSUBTREECHECK, accept anything
  35  * if not, require that we can walk up to exp->ex_dentry
  36  * doing some checks on the 'x' bits
  37  */
  38 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  39 {
  40         struct svc_export *exp = expv;
  41         int rv;
  42         struct dentry *tdentry;
  43         struct dentry *parent;
  44
  45         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  46                 return 1;
  47
  48         tdentry = dget(dentry);
  49         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
  50                 /* make sure parents give x permission to user */
  51                 int err;
  52                 parent = dget_parent(tdentry);
  53                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  54                 if (err < 0) {
  55                         dput(parent);
  56                         break;
  57                 }
  58                 dput(tdentry);
  59                 tdentry = parent;
  60         }
  61         if (tdentry != exp->ex_dentry)
  62                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  63         rv = (tdentry == exp->ex_dentry);
  64         dput(tdentry);
  65         return rv;
  66 }
  67
  68 /* Type check. The correct error return for type mismatches does not seem to be
  69  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  70  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  71  * the write call).
  72  */
  73 static inline __be32
  74 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  75 {
  76         /* Type can be negative when creating hardlinks - not to a dir */
  77         if (type > 0 && (mode & S_IFMT) != type) {
  78                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  79                         return nfserr_symlink;
  80                 else if (type == S_IFDIR)
  81                         return nfserr_notdir;
  82                 else if ((mode & S_IFMT) == S_IFDIR)
  83                         return nfserr_isdir;
  84                 else
  85                         return nfserr_inval;
  86         }
  87         if (type < 0 && (mode & S_IFMT) == -type) {
  88                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  89                         return nfserr_symlink;
  90                 else if (type == -S_IFDIR)
  91                         return nfserr_isdir;
  92                 else
  93                         return nfserr_notdir;
  94         }
  95         return 0;
  96 }
  97
  98 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
  99                                           struct svc_export *exp)
 100 {
 101         /* Check if the request originated from a secure port. */
 102         if (!rqstp->rq_secure && EX_SECURE(exp)) {
 103                 char buf[RPC_MAX_ADDRBUFLEN];
 104                 dprintk(KERN_WARNING
 105                        "nfsd: request from insecure port %s!\n",
 106                        svc_print_addr(rqstp, buf, sizeof(buf)));
 107                 return nfserr_perm;
 108         }
 109
 110         /* Set user creds for this exportpoint */
 111         return nfserrno(nfsd_setuser(rqstp, exp));
 112 }
 113
 114 /*
 115  * Perform sanity checks on the dentry in a client's file handle.
 116  *
 117  * Note that the file handle dentry may need to be freed even after
 118  * an error return.
 119  *
 120  * This is only called at the start of an nfsproc call, so fhp points to
 121  * a svc_fh which is all 0 except for the over-the-wire file handle.
 122  */
 123 __be32
 124 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 125 {
 126         struct knfsd_fh *fh = &fhp->fh_handle;
 127         struct svc_export *exp = NULL;
 128         struct dentry   *dentry;
 129         __be32          error = 0;
 130
 131         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 132
 133         if (!fhp->fh_dentry) {
 134                 struct fid *fid = NULL, sfid;
 135                 int fileid_type;
 136                 int data_left = fh->fh_size/4;
 137
 138                 error = nfserr_stale;
 139                 if (rqstp->rq_vers > 2)
 140                         error = nfserr_badhandle;
 141                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 142                         return nfserr_nofilehandle;
 143
 144                 if (fh->fh_version == 1) {
 145                         int len;
 146                         if (--data_left<0) goto out;
 147                         switch (fh->fh_auth_type) {
 148                         case 0: break;
 149                         default: goto out;
 150                         }
 151                         len = key_len(fh->fh_fsid_type) / 4;
 152                         if (len == 0) goto out;
 153                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 154                                 /* deprecated, convert to type 3 */
 155                                 len = key_len(FSID_ENCODE_DEV)/4;
 156                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 157                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 158                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 159                         }
 160                         if ((data_left -= len)<0) goto out;
 161                         exp = rqst_exp_find(rqstp, fh->fh_fsid_type,
 162                                             fh->fh_auth);
 163                         fid = (struct fid *)(fh->fh_auth + len);
 164                 } else {
 165                         __u32 tfh[2];
 166                         dev_t xdev;
 167                         ino_t xino;
 168                         if (fh->fh_size != NFS_FHSIZE)
 169                                 goto out;
 170                         /* assume old filehandle format */
 171                         xdev = old_decode_dev(fh->ofh_xdev);
 172                         xino = u32_to_ino_t(fh->ofh_xino);
 173                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 174                         exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 175                 }
 176
 177                 error = nfserr_stale;
 178                 if (PTR_ERR(exp) == -ENOENT)
 179                         goto out;
 180
 181                 if (IS_ERR(exp)) {
 182                         error = nfserrno(PTR_ERR(exp));
 183                         goto out;
 184                 }
 185
 186                 error = nfsd_setuser_and_check_port(rqstp, exp);
 187                 if (error)
 188                         goto out;
 189
 190                 /*
 191                  * Look up the dentry using the NFS file handle.
 192                  */
 193                 error = nfserr_stale;
 194                 if (rqstp->rq_vers > 2)
 195                         error = nfserr_badhandle;
 196
 197                 if (fh->fh_version != 1) {
 198                         sfid.i32.ino = fh->ofh_ino;
 199                         sfid.i32.gen = fh->ofh_generation;
 200                         sfid.i32.parent_ino = fh->ofh_dirino;
 201                         fid = &sfid;
 202                         data_left = 3;
 203                         if (fh->ofh_dirino == 0)
 204                                 fileid_type = FILEID_INO32_GEN;
 205                         else
 206                                 fileid_type = FILEID_INO32_GEN_PARENT;
 207                 } else
 208                         fileid_type = fh->fh_fileid_type;
 209
 210                 if (fileid_type == FILEID_ROOT)
 211                         dentry = dget(exp->ex_dentry);
 212                 else {
 213                         dentry = exportfs_decode_fh(exp->ex_mnt, fid,
 214                                         data_left, fileid_type,
 215                                         nfsd_acceptable, exp);
 216                 }
 217                 if (dentry == NULL)
 218                         goto out;
 219                 if (IS_ERR(dentry)) {
 220                         if (PTR_ERR(dentry) != -EINVAL)
 221                                 error = nfserrno(PTR_ERR(dentry));
 222                         goto out;
 223                 }
 224
 225                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 226                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 227                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 228                                dentry->d_parent->d_name.name, dentry->d_name.name);
 229                 }
 230
 231                 fhp->fh_dentry = dentry;
 232                 fhp->fh_export = exp;
 233                 nfsd_nr_verified++;
 234         } else {
 235                 /*
 236                  * just rechecking permissions
 237                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create
 238                  * does as well)
 239                  */
 240                 dprintk("nfsd: fh_verify - just checking\n");
 241                 dentry = fhp->fh_dentry;
 242                 exp = fhp->fh_export;
 243                 /*
 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                  */
 250                 error = nfsd_setuser_and_check_port(rqstp, exp);
 251                 if (error)
 252                         goto out;
 253         }
 254         cache_get(&exp->h);
 255
 256
 257         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 258         if (error)
 259                 goto out;
 260
 261         if (!(access & MAY_LOCK)) {
 262                 /*
 263                  * pseudoflavor restrictions are not enforced on NLM,
 264                  * which clients virtually always use auth_sys for,
 265                  * even while using RPCSEC_GSS for NFS.
 266                  */
 267                 error = check_nfsd_access(exp, rqstp);
 268                 if (error)
 269                         goto out;
 270         }
 271
 272         /* Finally, check access permissions. */
 273         error = nfsd_permission(rqstp, exp, dentry, access);
 274
 275         if (error) {
 276                 dprintk("fh_verify: %s/%s permission failure, "
 277                         "acc=%x, error=%d\n",
 278                         dentry->d_parent->d_name.name,
 279                         dentry->d_name.name,
 280                         access, ntohl(error));
 281         }
 282 out:
 283         if (exp && !IS_ERR(exp))
 284                 exp_put(exp);
 285         if (error == nfserr_stale)
 286                 nfsdstats.fh_stale++;
 287         return error;
 288 }
 289
 290
 291 /*
 292  * Compose a file handle for an NFS reply.
 293  *
 294  * Note that when first composed, the dentry may not yet have
 295  * an inode.  In this case a call to fh_update should be made
 296  * before the fh goes out on the wire ...
 297  */
 298 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 299                 struct dentry *dentry)
 300 {
 301         if (dentry != exp->ex_dentry) {
 302                 struct fid *fid = (struct fid *)
 303                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
 304                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 305                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 306
 307                 fhp->fh_handle.fh_fileid_type =
 308                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 309                 fhp->fh_handle.fh_size += maxsize * 4;
 310         } else {
 311                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 312         }
 313 }
 314
 315 /*
 316  * for composing old style file handles
 317  */
 318 static inline void _fh_update_old(struct dentry *dentry,
 319                                   struct svc_export *exp,
 320                                   struct knfsd_fh *fh)
 321 {
 322         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 323         fh->ofh_generation = dentry->d_inode->i_generation;
 324         if (S_ISDIR(dentry->d_inode->i_mode) ||
 325             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 326                 fh->ofh_dirino = 0;
 327 }
 328
 329 __be32
 330 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 331            struct svc_fh *ref_fh)
 332 {
 333         /* ref_fh is a reference file handle.
 334          * if it is non-null and for the same filesystem, then we should compose
 335          * a filehandle which is of the same version, where possible.
 336          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 337          * Then create a 32byte filehandle using nfs_fhbase_old
 338          *
 339          */
 340
 341         u8 version;
 342         u8 fsid_type = 0;
 343         struct inode * inode = dentry->d_inode;
 344         struct dentry *parent = dentry->d_parent;
 345         __u32 *datap;
 346         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 347         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 348
 349         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 350                 MAJOR(ex_dev), MINOR(ex_dev),
 351                 (long) exp->ex_dentry->d_inode->i_ino,
 352                 parent->d_name.name, dentry->d_name.name,
 353                 (inode ? inode->i_ino : 0));
 354
 355         /* Choose filehandle version and fsid type based on
 356          * the reference filehandle (if it is in the same export)
 357          * or the export options.
 358          */
 359  retry:
 360         version = 1;
 361         if (ref_fh && ref_fh->fh_export == exp) {
 362                 version = ref_fh->fh_handle.fh_version;
 363                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 364
 365                 if (ref_fh == fhp)
 366                         fh_put(ref_fh);
 367                 ref_fh = NULL;
 368
 369                 switch (version) {
 370                 case 0xca:
 371                         fsid_type = FSID_DEV;
 372                         break;
 373                 case 1:
 374                         break;
 375                 default:
 376                         goto retry;
 377                 }
 378
 379                 /* Need to check that this type works for this
 380                  * export point.  As the fsid -> filesystem mapping
 381                  * was guided by user-space, there is no guarantee
 382                  * that the filesystem actually supports that fsid
 383                  * type. If it doesn't we loop around again without
 384                  * ref_fh set.
 385                  */
 386                 switch(fsid_type) {
 387                 case FSID_DEV:
 388                         if (!old_valid_dev(ex_dev))
 389                                 goto retry;
 390                         /* FALL THROUGH */
 391                 case FSID_MAJOR_MINOR:
 392                 case FSID_ENCODE_DEV:
 393                         if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
 394                               & FS_REQUIRES_DEV))
 395                                 goto retry;
 396                         break;
 397                 case FSID_NUM:
 398                         if (! (exp->ex_flags & NFSEXP_FSID))
 399                                 goto retry;
 400                         break;
 401                 case FSID_UUID8:
 402                 case FSID_UUID16:
 403                         if (!root_export)
 404                                 goto retry;
 405                         /* fall through */
 406                 case FSID_UUID4_INUM:
 407                 case FSID_UUID16_INUM:
 408                         if (exp->ex_uuid == NULL)
 409                                 goto retry;
 410                         break;
 411                 }
 412         } else if (exp->ex_uuid) {
 413                 if (fhp->fh_maxsize >= 64) {
 414                         if (root_export)
 415                                 fsid_type = FSID_UUID16;
 416                         else
 417                                 fsid_type = FSID_UUID16_INUM;
 418                 } else {
 419                         if (root_export)
 420                                 fsid_type = FSID_UUID8;
 421                         else
 422                                 fsid_type = FSID_UUID4_INUM;
 423                 }
 424         } else if (exp->ex_flags & NFSEXP_FSID)
 425                 fsid_type = FSID_NUM;
 426         else if (!old_valid_dev(ex_dev))
 427                 /* for newer device numbers, we must use a newer fsid format */
 428                 fsid_type = FSID_ENCODE_DEV;
 429         else
 430                 fsid_type = FSID_DEV;
 431
 432         if (ref_fh == fhp)
 433                 fh_put(ref_fh);
 434
 435         if (fhp->fh_locked || fhp->fh_dentry) {
 436                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 437                        parent->d_name.name, dentry->d_name.name);
 438         }
 439         if (fhp->fh_maxsize < NFS_FHSIZE)
 440                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 441                        fhp->fh_maxsize,
 442                        parent->d_name.name, dentry->d_name.name);
 443
 444         fhp->fh_dentry = dget(dentry); /* our internal copy */
 445         fhp->fh_export = exp;
 446         cache_get(&exp->h);
 447
 448         if (version == 0xca) {
 449                 /* old style filehandle please */
 450                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 451                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 452                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 453                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 454                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 455                 fhp->fh_handle.ofh_xino =
 456                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 457                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 458                 if (inode)
 459                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 460         } else {
 461                 int len;
 462                 fhp->fh_handle.fh_version = 1;
 463                 fhp->fh_handle.fh_auth_type = 0;
 464                 datap = fhp->fh_handle.fh_auth+0;
 465                 fhp->fh_handle.fh_fsid_type = fsid_type;
 466                 mk_fsid(fsid_type, datap, ex_dev,
 467                         exp->ex_dentry->d_inode->i_ino,
 468                         exp->ex_fsid, exp->ex_uuid);
 469
 470                 len = key_len(fsid_type);
 471                 datap += len/4;
 472                 fhp->fh_handle.fh_size = 4 + len;
 473
 474                 if (inode)
 475                         _fh_update(fhp, exp, dentry);
 476                 if (fhp->fh_handle.fh_fileid_type == 255)
 477                         return nfserr_opnotsupp;
 478         }
 479
 480         nfsd_nr_verified++;
 481         return 0;
 482 }
 483
 484 /*
 485  * Update file handle information after changing a dentry.
 486  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 487  */
 488 __be32
 489 fh_update(struct svc_fh *fhp)
 490 {
 491         struct dentry *dentry;
 492
 493         if (!fhp->fh_dentry)
 494                 goto out_bad;
 495
 496         dentry = fhp->fh_dentry;
 497         if (!dentry->d_inode)
 498                 goto out_negative;
 499         if (fhp->fh_handle.fh_version != 1) {
 500                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 501         } else {
 502                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 503                         goto out;
 504
 505                 _fh_update(fhp, fhp->fh_export, dentry);
 506                 if (fhp->fh_handle.fh_fileid_type == 255)
 507                         return nfserr_opnotsupp;
 508         }
 509 out:
 510         return 0;
 511
 512 out_bad:
 513         printk(KERN_ERR "fh_update: fh not verified!\n");
 514         goto out;
 515 out_negative:
 516         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 517                 dentry->d_parent->d_name.name, dentry->d_name.name);
 518         goto out;
 519 }
 520
 521 /*
 522  * Release a file handle.
 523  */
 524 void
 525 fh_put(struct svc_fh *fhp)
 526 {
 527         struct dentry * dentry = fhp->fh_dentry;
 528         struct svc_export * exp = fhp->fh_export;
 529         if (dentry) {
 530                 fh_unlock(fhp);
 531                 fhp->fh_dentry = NULL;
 532                 dput(dentry);
 533 #ifdef CONFIG_NFSD_V3
 534                 fhp->fh_pre_saved = 0;
 535                 fhp->fh_post_saved = 0;
 536 #endif
 537                 nfsd_nr_put++;
 538         }
 539         if (exp) {
 540                 cache_put(&exp->h, &svc_export_cache);
 541                 fhp->fh_export = NULL;
 542         }
 543         return;
 544 }
 545
 546 /*
 547  * Shorthand for dprintk()'s
 548  */
 549 char * SVCFH_fmt(struct svc_fh *fhp)
 550 {
 551         struct knfsd_fh *fh = &fhp->fh_handle;
 552
 553         static char buf[80];
 554         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 555                 fh->fh_size,
 556                 fh->fh_base.fh_pad[0],
 557                 fh->fh_base.fh_pad[1],
 558                 fh->fh_base.fh_pad[2],
 559                 fh->fh_base.fh_pad[3],
 560                 fh->fh_base.fh_pad[4],
 561                 fh->fh_base.fh_pad[5]);
 562         return buf;
 563 }
 564
 565 enum fsid_source fsid_source(struct svc_fh *fhp)
 566 {
 567         if (fhp->fh_handle.fh_version != 1)
 568                 return FSIDSOURCE_DEV;
 569         switch(fhp->fh_handle.fh_fsid_type) {
 570         case FSID_DEV:
 571         case FSID_ENCODE_DEV:
 572         case FSID_MAJOR_MINOR:
 573                 if (fhp->fh_export->ex_dentry->d_inode->i_sb->s_type->fs_flags
 574                     & FS_REQUIRES_DEV)
 575                         return FSIDSOURCE_DEV;
 576                 break;
 577         case FSID_NUM:
 578                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 579                         return FSIDSOURCE_FSID;
 580                 break;
 581         default:
 582                 break;
 583         }
 584         /* either a UUID type filehandle, or the filehandle doesn't
 585          * match the export.
 586          */
 587         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 588                 return FSIDSOURCE_FSID;
 589         if (fhp->fh_export->ex_uuid)
 590                 return FSIDSOURCE_UUID;
 591         return FSIDSOURCE_DEV;
 592 }