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 /*
  99  * Perform sanity checks on the dentry in a client's file handle.
 100  *
 101  * Note that the file handle dentry may need to be freed even after
 102  * an error return.
 103  *
 104  * This is only called at the start of an nfsproc call, so fhp points to
 105  * a svc_fh which is all 0 except for the over-the-wire file handle.
 106  */
 107 __be32
 108 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 109 {
 110         struct knfsd_fh *fh = &fhp->fh_handle;
 111         struct svc_export *exp = NULL;
 112         struct dentry   *dentry;
 113         __be32          error = 0;
 114
 115         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 116
 117         if (!fhp->fh_dentry) {
 118                 struct fid *fid = NULL, sfid;
 119                 int fileid_type;
 120                 int data_left = fh->fh_size/4;
 121
 122                 error = nfserr_stale;
 123                 if (rqstp->rq_vers > 2)
 124                         error = nfserr_badhandle;
 125                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 126                         return nfserr_nofilehandle;
 127
 128                 if (fh->fh_version == 1) {
 129                         int len;
 130                         if (--data_left<0) goto out;
 131                         switch (fh->fh_auth_type) {
 132                         case 0: break;
 133                         default: goto out;
 134                         }
 135                         len = key_len(fh->fh_fsid_type) / 4;
 136                         if (len == 0) goto out;
 137                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 138                                 /* deprecated, convert to type 3 */
 139                                 len = key_len(FSID_ENCODE_DEV)/4;
 140                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 141                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 142                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 143                         }
 144                         if ((data_left -= len)<0) goto out;
 145                         exp = rqst_exp_find(rqstp, fh->fh_fsid_type,
 146                                             fh->fh_auth);
 147                         fid = (struct fid *)(fh->fh_auth + len);
 148                 } else {
 149                         __u32 tfh[2];
 150                         dev_t xdev;
 151                         ino_t xino;
 152                         if (fh->fh_size != NFS_FHSIZE)
 153                                 goto out;
 154                         /* assume old filehandle format */
 155                         xdev = old_decode_dev(fh->ofh_xdev);
 156                         xino = u32_to_ino_t(fh->ofh_xino);
 157                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 158                         exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 159                 }
 160
 161                 error = nfserr_stale;
 162                 if (PTR_ERR(exp) == -ENOENT)
 163                         goto out;
 164
 165                 if (IS_ERR(exp)) {
 166                         error = nfserrno(PTR_ERR(exp));
 167                         goto out;
 168                 }
 169
 170                 /* Check if the request originated from a secure port. */
 171                 error = nfserr_perm;
 172                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 173                         char buf[RPC_MAX_ADDRBUFLEN];
 174                         printk(KERN_WARNING
 175                                "nfsd: request from insecure port %s!\n",
 176                                svc_print_addr(rqstp, buf, sizeof(buf)));
 177                         goto out;
 178                 }
 179
 180                 /* Set user creds for this exportpoint */
 181                 error = nfserrno(nfsd_setuser(rqstp, exp));
 182                 if (error)
 183                         goto out;
 184
 185                 /*
 186                  * Look up the dentry using the NFS file handle.
 187                  */
 188                 error = nfserr_stale;
 189                 if (rqstp->rq_vers > 2)
 190                         error = nfserr_badhandle;
 191
 192                 if (fh->fh_version != 1) {
 193                         sfid.i32.ino = fh->ofh_ino;
 194                         sfid.i32.gen = fh->ofh_generation;
 195                         sfid.i32.parent_ino = fh->ofh_dirino;
 196                         fid = &sfid;
 197                         data_left = 3;
 198                         if (fh->ofh_dirino == 0)
 199                                 fileid_type = FILEID_INO32_GEN;
 200                         else
 201                                 fileid_type = FILEID_INO32_GEN_PARENT;
 202                 } else
 203                         fileid_type = fh->fh_fileid_type;
 204
 205                 if (fileid_type == FILEID_ROOT)
 206                         dentry = dget(exp->ex_dentry);
 207                 else {
 208                         dentry = exportfs_decode_fh(exp->ex_mnt, fid,
 209                                         data_left, fileid_type,
 210                                         nfsd_acceptable, exp);
 211                 }
 212                 if (dentry == NULL)
 213                         goto out;
 214                 if (IS_ERR(dentry)) {
 215                         if (PTR_ERR(dentry) != -EINVAL)
 216                                 error = nfserrno(PTR_ERR(dentry));
 217                         goto out;
 218                 }
 219
 220                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 221                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 222                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 223                                dentry->d_parent->d_name.name, dentry->d_name.name);
 224                 }
 225
 226                 fhp->fh_dentry = dentry;
 227                 fhp->fh_export = exp;
 228                 nfsd_nr_verified++;
 229         } else {
 230                 /* just rechecking permissions
 231                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 232                  */
 233                 dprintk("nfsd: fh_verify - just checking\n");
 234                 dentry = fhp->fh_dentry;
 235                 exp = fhp->fh_export;
 236                 /* Set user creds for this exportpoint; necessary even
 237                  * in the "just checking" case because this may be a
 238                  * filehandle that was created by fh_compose, and that
 239                  * is about to be used in another nfsv4 compound
 240                  * operation */
 241                 error = nfserrno(nfsd_setuser(rqstp, exp));
 242                 if (error)
 243                         goto out;
 244         }
 245         cache_get(&exp->h);
 246
 247
 248         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 249         if (error)
 250                 goto out;
 251
 252         if (!(access & MAY_LOCK)) {
 253                 /*
 254                  * pseudoflavor restrictions are not enforced on NLM,
 255                  * which clients virtually always use auth_sys for,
 256                  * even while using RPCSEC_GSS for NFS.
 257                  */
 258                 error = check_nfsd_access(exp, rqstp);
 259                 if (error)
 260                         goto out;
 261         }
 262
 263         /* Finally, check access permissions. */
 264         error = nfsd_permission(rqstp, exp, dentry, access);
 265
 266         if (error) {
 267                 dprintk("fh_verify: %s/%s permission failure, "
 268                         "acc=%x, error=%d\n",
 269                         dentry->d_parent->d_name.name,
 270                         dentry->d_name.name,
 271                         access, ntohl(error));
 272         }
 273 out:
 274         if (exp && !IS_ERR(exp))
 275                 exp_put(exp);
 276         if (error == nfserr_stale)
 277                 nfsdstats.fh_stale++;
 278         return error;
 279 }
 280
 281
 282 /*
 283  * Compose a file handle for an NFS reply.
 284  *
 285  * Note that when first composed, the dentry may not yet have
 286  * an inode.  In this case a call to fh_update should be made
 287  * before the fh goes out on the wire ...
 288  */
 289 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 290                 struct dentry *dentry)
 291 {
 292         if (dentry != exp->ex_dentry) {
 293                 struct fid *fid = (struct fid *)
 294                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
 295                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 296                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 297
 298                 fhp->fh_handle.fh_fileid_type =
 299                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 300                 fhp->fh_handle.fh_size += maxsize * 4;
 301         } else {
 302                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 303         }
 304 }
 305
 306 /*
 307  * for composing old style file handles
 308  */
 309 static inline void _fh_update_old(struct dentry *dentry,
 310                                   struct svc_export *exp,
 311                                   struct knfsd_fh *fh)
 312 {
 313         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 314         fh->ofh_generation = dentry->d_inode->i_generation;
 315         if (S_ISDIR(dentry->d_inode->i_mode) ||
 316             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 317                 fh->ofh_dirino = 0;
 318 }
 319
 320 __be32
 321 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 322            struct svc_fh *ref_fh)
 323 {
 324         /* ref_fh is a reference file handle.
 325          * if it is non-null and for the same filesystem, then we should compose
 326          * a filehandle which is of the same version, where possible.
 327          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 328          * Then create a 32byte filehandle using nfs_fhbase_old
 329          *
 330          */
 331
 332         u8 version;
 333         u8 fsid_type = 0;
 334         struct inode * inode = dentry->d_inode;
 335         struct dentry *parent = dentry->d_parent;
 336         __u32 *datap;
 337         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 338         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 339
 340         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 341                 MAJOR(ex_dev), MINOR(ex_dev),
 342                 (long) exp->ex_dentry->d_inode->i_ino,
 343                 parent->d_name.name, dentry->d_name.name,
 344                 (inode ? inode->i_ino : 0));
 345
 346         /* Choose filehandle version and fsid type based on
 347          * the reference filehandle (if it is in the same export)
 348          * or the export options.
 349          */
 350  retry:
 351         version = 1;
 352         if (ref_fh && ref_fh->fh_export == exp) {
 353                 version = ref_fh->fh_handle.fh_version;
 354                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 355
 356                 if (ref_fh == fhp)
 357                         fh_put(ref_fh);
 358                 ref_fh = NULL;
 359
 360                 switch (version) {
 361                 case 0xca:
 362                         fsid_type = FSID_DEV;
 363                         break;
 364                 case 1:
 365                         break;
 366                 default:
 367                         goto retry;
 368                 }
 369
 370                 /* Need to check that this type works for this
 371                  * export point.  As the fsid -> filesystem mapping
 372                  * was guided by user-space, there is no guarantee
 373                  * that the filesystem actually supports that fsid
 374                  * type. If it doesn't we loop around again without
 375                  * ref_fh set.
 376                  */
 377                 switch(fsid_type) {
 378                 case FSID_DEV:
 379                         if (!old_valid_dev(ex_dev))
 380                                 goto retry;
 381                         /* FALL THROUGH */
 382                 case FSID_MAJOR_MINOR:
 383                 case FSID_ENCODE_DEV:
 384                         if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
 385                               & FS_REQUIRES_DEV))
 386                                 goto retry;
 387                         break;
 388                 case FSID_NUM:
 389                         if (! (exp->ex_flags & NFSEXP_FSID))
 390                                 goto retry;
 391                         break;
 392                 case FSID_UUID8:
 393                 case FSID_UUID16:
 394                         if (!root_export)
 395                                 goto retry;
 396                         /* fall through */
 397                 case FSID_UUID4_INUM:
 398                 case FSID_UUID16_INUM:
 399                         if (exp->ex_uuid == NULL)
 400                                 goto retry;
 401                         break;
 402                 }
 403         } else if (exp->ex_uuid) {
 404                 if (fhp->fh_maxsize >= 64) {
 405                         if (root_export)
 406                                 fsid_type = FSID_UUID16;
 407                         else
 408                                 fsid_type = FSID_UUID16_INUM;
 409                 } else {
 410                         if (root_export)
 411                                 fsid_type = FSID_UUID8;
 412                         else
 413                                 fsid_type = FSID_UUID4_INUM;
 414                 }
 415         } else if (exp->ex_flags & NFSEXP_FSID)
 416                 fsid_type = FSID_NUM;
 417         else if (!old_valid_dev(ex_dev))
 418                 /* for newer device numbers, we must use a newer fsid format */
 419                 fsid_type = FSID_ENCODE_DEV;
 420         else
 421                 fsid_type = FSID_DEV;
 422
 423         if (ref_fh == fhp)
 424                 fh_put(ref_fh);
 425
 426         if (fhp->fh_locked || fhp->fh_dentry) {
 427                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 428                        parent->d_name.name, dentry->d_name.name);
 429         }
 430         if (fhp->fh_maxsize < NFS_FHSIZE)
 431                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 432                        fhp->fh_maxsize,
 433                        parent->d_name.name, dentry->d_name.name);
 434
 435         fhp->fh_dentry = dget(dentry); /* our internal copy */
 436         fhp->fh_export = exp;
 437         cache_get(&exp->h);
 438
 439         if (version == 0xca) {
 440                 /* old style filehandle please */
 441                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 442                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 443                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 444                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 445                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 446                 fhp->fh_handle.ofh_xino =
 447                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 448                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 449                 if (inode)
 450                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 451         } else {
 452                 int len;
 453                 fhp->fh_handle.fh_version = 1;
 454                 fhp->fh_handle.fh_auth_type = 0;
 455                 datap = fhp->fh_handle.fh_auth+0;
 456                 fhp->fh_handle.fh_fsid_type = fsid_type;
 457                 mk_fsid(fsid_type, datap, ex_dev,
 458                         exp->ex_dentry->d_inode->i_ino,
 459                         exp->ex_fsid, exp->ex_uuid);
 460
 461                 len = key_len(fsid_type);
 462                 datap += len/4;
 463                 fhp->fh_handle.fh_size = 4 + len;
 464
 465                 if (inode)
 466                         _fh_update(fhp, exp, dentry);
 467                 if (fhp->fh_handle.fh_fileid_type == 255)
 468                         return nfserr_opnotsupp;
 469         }
 470
 471         nfsd_nr_verified++;
 472         return 0;
 473 }
 474
 475 /*
 476  * Update file handle information after changing a dentry.
 477  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 478  */
 479 __be32
 480 fh_update(struct svc_fh *fhp)
 481 {
 482         struct dentry *dentry;
 483
 484         if (!fhp->fh_dentry)
 485                 goto out_bad;
 486
 487         dentry = fhp->fh_dentry;
 488         if (!dentry->d_inode)
 489                 goto out_negative;
 490         if (fhp->fh_handle.fh_version != 1) {
 491                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 492         } else {
 493                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 494                         goto out;
 495
 496                 _fh_update(fhp, fhp->fh_export, dentry);
 497                 if (fhp->fh_handle.fh_fileid_type == 255)
 498                         return nfserr_opnotsupp;
 499         }
 500 out:
 501         return 0;
 502
 503 out_bad:
 504         printk(KERN_ERR "fh_update: fh not verified!\n");
 505         goto out;
 506 out_negative:
 507         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 508                 dentry->d_parent->d_name.name, dentry->d_name.name);
 509         goto out;
 510 }
 511
 512 /*
 513  * Release a file handle.
 514  */
 515 void
 516 fh_put(struct svc_fh *fhp)
 517 {
 518         struct dentry * dentry = fhp->fh_dentry;
 519         struct svc_export * exp = fhp->fh_export;
 520         if (dentry) {
 521                 fh_unlock(fhp);
 522                 fhp->fh_dentry = NULL;
 523                 dput(dentry);
 524 #ifdef CONFIG_NFSD_V3
 525                 fhp->fh_pre_saved = 0;
 526                 fhp->fh_post_saved = 0;
 527 #endif
 528                 nfsd_nr_put++;
 529         }
 530         if (exp) {
 531                 cache_put(&exp->h, &svc_export_cache);
 532                 fhp->fh_export = NULL;
 533         }
 534         return;
 535 }
 536
 537 /*
 538  * Shorthand for dprintk()'s
 539  */
 540 char * SVCFH_fmt(struct svc_fh *fhp)
 541 {
 542         struct knfsd_fh *fh = &fhp->fh_handle;
 543
 544         static char buf[80];
 545         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 546                 fh->fh_size,
 547                 fh->fh_base.fh_pad[0],
 548                 fh->fh_base.fh_pad[1],
 549                 fh->fh_base.fh_pad[2],
 550                 fh->fh_base.fh_pad[3],
 551                 fh->fh_base.fh_pad[4],
 552                 fh->fh_base.fh_pad[5]);
 553         return buf;
 554 }
 555
 556 enum fsid_source fsid_source(struct svc_fh *fhp)
 557 {
 558         if (fhp->fh_handle.fh_version != 1)
 559                 return FSIDSOURCE_DEV;
 560         switch(fhp->fh_handle.fh_fsid_type) {
 561         case FSID_DEV:
 562         case FSID_ENCODE_DEV:
 563         case FSID_MAJOR_MINOR:
 564                 if (fhp->fh_export->ex_dentry->d_inode->i_sb->s_type->fs_flags
 565                     & FS_REQUIRES_DEV)
 566                         return FSIDSOURCE_DEV;
 567                 break;
 568         case FSID_NUM:
 569                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 570                         return FSIDSOURCE_FSID;
 571                 break;
 572         default:
 573                 break;
 574         }
 575         /* either a UUID type filehandle, or the filehandle doesn't
 576          * match the export.
 577          */
 578         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 579                 return FSIDSOURCE_FSID;
 580         if (fhp->fh_export->ex_uuid)
 581                 return FSIDSOURCE_UUID;
 582         return FSIDSOURCE_DEV;
 583 }