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                 __u32 *datap=NULL;
 119                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 120                 int fileid_type;
 121                 int data_left = fh->fh_size/4;
 122
 123                 error = nfserr_stale;
 124                 if (rqstp->rq_vers > 2)
 125                         error = nfserr_badhandle;
 126                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 127                         return nfserr_nofilehandle;
 128
 129                 if (fh->fh_version == 1) {
 130                         int len;
 131                         datap = fh->fh_auth;
 132                         if (--data_left<0) goto out;
 133                         switch (fh->fh_auth_type) {
 134                         case 0: break;
 135                         default: goto out;
 136                         }
 137                         len = key_len(fh->fh_fsid_type) / 4;
 138                         if (len == 0) goto out;
 139                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 140                                 /* deprecated, convert to type 3 */
 141                                 len = key_len(FSID_ENCODE_DEV)/4;
 142                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 143                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 144                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 145                         }
 146                         if ((data_left -= len)<0) goto out;
 147                         exp = rqst_exp_find(rqstp, fh->fh_fsid_type, datap);
 148                         datap += len;
 149                 } else {
 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                         tfh[0] = fh->ofh_ino;
 194                         tfh[1] = fh->ofh_generation;
 195                         tfh[2] = fh->ofh_dirino;
 196                         datap = tfh;
 197                         data_left = 3;
 198                         if (fh->ofh_dirino == 0)
 199                                 fileid_type = 1;
 200                         else
 201                                 fileid_type = 2;
 202                 } else
 203                         fileid_type = fh->fh_fileid_type;
 204
 205                 if (fileid_type == 0)
 206                         dentry = dget(exp->ex_dentry);
 207                 else {
 208                         dentry = exportfs_decode_fh(exp->ex_mnt, datap,
 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 inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 290                              __u32 *datap, int *maxsize)
 291 {
 292         if (dentry == exp->ex_dentry) {
 293                 *maxsize = 0;
 294                 return 0;
 295         }
 296
 297         return exportfs_encode_fh(dentry, datap, maxsize,
 298                           !(exp->ex_flags & NFSEXP_NOSUBTREECHECK));
 299 }
 300
 301 /*
 302  * for composing old style file handles
 303  */
 304 static inline void _fh_update_old(struct dentry *dentry,
 305                                   struct svc_export *exp,
 306                                   struct knfsd_fh *fh)
 307 {
 308         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 309         fh->ofh_generation = dentry->d_inode->i_generation;
 310         if (S_ISDIR(dentry->d_inode->i_mode) ||
 311             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 312                 fh->ofh_dirino = 0;
 313 }
 314
 315 __be32
 316 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 317            struct svc_fh *ref_fh)
 318 {
 319         /* ref_fh is a reference file handle.
 320          * if it is non-null and for the same filesystem, then we should compose
 321          * a filehandle which is of the same version, where possible.
 322          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 323          * Then create a 32byte filehandle using nfs_fhbase_old
 324          *
 325          */
 326
 327         u8 version;
 328         u8 fsid_type = 0;
 329         struct inode * inode = dentry->d_inode;
 330         struct dentry *parent = dentry->d_parent;
 331         __u32 *datap;
 332         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 333         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 334
 335         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 336                 MAJOR(ex_dev), MINOR(ex_dev),
 337                 (long) exp->ex_dentry->d_inode->i_ino,
 338                 parent->d_name.name, dentry->d_name.name,
 339                 (inode ? inode->i_ino : 0));
 340
 341         /* Choose filehandle version and fsid type based on
 342          * the reference filehandle (if it is in the same export)
 343          * or the export options.
 344          */
 345  retry:
 346         version = 1;
 347         if (ref_fh && ref_fh->fh_export == exp) {
 348                 version = ref_fh->fh_handle.fh_version;
 349                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 350
 351                 if (ref_fh == fhp)
 352                         fh_put(ref_fh);
 353                 ref_fh = NULL;
 354
 355                 switch (version) {
 356                 case 0xca:
 357                         fsid_type = FSID_DEV;
 358                         break;
 359                 case 1:
 360                         break;
 361                 default:
 362                         goto retry;
 363                 }
 364
 365                 /* Need to check that this type works for this
 366                  * export point.  As the fsid -> filesystem mapping
 367                  * was guided by user-space, there is no guarantee
 368                  * that the filesystem actually supports that fsid
 369                  * type. If it doesn't we loop around again without
 370                  * ref_fh set.
 371                  */
 372                 switch(fsid_type) {
 373                 case FSID_DEV:
 374                         if (!old_valid_dev(ex_dev))
 375                                 goto retry;
 376                         /* FALL THROUGH */
 377                 case FSID_MAJOR_MINOR:
 378                 case FSID_ENCODE_DEV:
 379                         if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
 380                               & FS_REQUIRES_DEV))
 381                                 goto retry;
 382                         break;
 383                 case FSID_NUM:
 384                         if (! (exp->ex_flags & NFSEXP_FSID))
 385                                 goto retry;
 386                         break;
 387                 case FSID_UUID8:
 388                 case FSID_UUID16:
 389                         if (!root_export)
 390                                 goto retry;
 391                         /* fall through */
 392                 case FSID_UUID4_INUM:
 393                 case FSID_UUID16_INUM:
 394                         if (exp->ex_uuid == NULL)
 395                                 goto retry;
 396                         break;
 397                 }
 398         } else if (exp->ex_uuid) {
 399                 if (fhp->fh_maxsize >= 64) {
 400                         if (root_export)
 401                                 fsid_type = FSID_UUID16;
 402                         else
 403                                 fsid_type = FSID_UUID16_INUM;
 404                 } else {
 405                         if (root_export)
 406                                 fsid_type = FSID_UUID8;
 407                         else
 408                                 fsid_type = FSID_UUID4_INUM;
 409                 }
 410         } else if (exp->ex_flags & NFSEXP_FSID)
 411                 fsid_type = FSID_NUM;
 412         else if (!old_valid_dev(ex_dev))
 413                 /* for newer device numbers, we must use a newer fsid format */
 414                 fsid_type = FSID_ENCODE_DEV;
 415         else
 416                 fsid_type = FSID_DEV;
 417
 418         if (ref_fh == fhp)
 419                 fh_put(ref_fh);
 420
 421         if (fhp->fh_locked || fhp->fh_dentry) {
 422                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 423                        parent->d_name.name, dentry->d_name.name);
 424         }
 425         if (fhp->fh_maxsize < NFS_FHSIZE)
 426                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 427                        fhp->fh_maxsize,
 428                        parent->d_name.name, dentry->d_name.name);
 429
 430         fhp->fh_dentry = dget(dentry); /* our internal copy */
 431         fhp->fh_export = exp;
 432         cache_get(&exp->h);
 433
 434         if (version == 0xca) {
 435                 /* old style filehandle please */
 436                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 437                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 438                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 439                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 440                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 441                 fhp->fh_handle.ofh_xino =
 442                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 443                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 444                 if (inode)
 445                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 446         } else {
 447                 int len;
 448                 fhp->fh_handle.fh_version = 1;
 449                 fhp->fh_handle.fh_auth_type = 0;
 450                 datap = fhp->fh_handle.fh_auth+0;
 451                 fhp->fh_handle.fh_fsid_type = fsid_type;
 452                 mk_fsid(fsid_type, datap, ex_dev,
 453                         exp->ex_dentry->d_inode->i_ino,
 454                         exp->ex_fsid, exp->ex_uuid);
 455
 456                 len = key_len(fsid_type);
 457                 datap += len/4;
 458                 fhp->fh_handle.fh_size = 4 + len;
 459
 460                 if (inode) {
 461                         int size = (fhp->fh_maxsize-len-4)/4;
 462                         fhp->fh_handle.fh_fileid_type =
 463                                 _fh_update(dentry, exp, datap, &size);
 464                         fhp->fh_handle.fh_size += size*4;
 465                 }
 466                 if (fhp->fh_handle.fh_fileid_type == 255)
 467                         return nfserr_opnotsupp;
 468         }
 469
 470         nfsd_nr_verified++;
 471         return 0;
 472 }
 473
 474 /*
 475  * Update file handle information after changing a dentry.
 476  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 477  */
 478 __be32
 479 fh_update(struct svc_fh *fhp)
 480 {
 481         struct dentry *dentry;
 482         __u32 *datap;
 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                 int size;
 494                 if (fhp->fh_handle.fh_fileid_type != 0)
 495                         goto out;
 496                 datap = fhp->fh_handle.fh_auth+
 497                         fhp->fh_handle.fh_size/4 -1;
 498                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 499                 fhp->fh_handle.fh_fileid_type =
 500                         _fh_update(dentry, fhp->fh_export, datap, &size);
 501                 fhp->fh_handle.fh_size += size*4;
 502                 if (fhp->fh_handle.fh_fileid_type == 255)
 503                         return nfserr_opnotsupp;
 504         }
 505 out:
 506         return 0;
 507
 508 out_bad:
 509         printk(KERN_ERR "fh_update: fh not verified!\n");
 510         goto out;
 511 out_negative:
 512         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 513                 dentry->d_parent->d_name.name, dentry->d_name.name);
 514         goto out;
 515 }
 516
 517 /*
 518  * Release a file handle.
 519  */
 520 void
 521 fh_put(struct svc_fh *fhp)
 522 {
 523         struct dentry * dentry = fhp->fh_dentry;
 524         struct svc_export * exp = fhp->fh_export;
 525         if (dentry) {
 526                 fh_unlock(fhp);
 527                 fhp->fh_dentry = NULL;
 528                 dput(dentry);
 529 #ifdef CONFIG_NFSD_V3
 530                 fhp->fh_pre_saved = 0;
 531                 fhp->fh_post_saved = 0;
 532 #endif
 533                 nfsd_nr_put++;
 534         }
 535         if (exp) {
 536                 cache_put(&exp->h, &svc_export_cache);
 537                 fhp->fh_export = NULL;
 538         }
 539         return;
 540 }
 541
 542 /*
 543  * Shorthand for dprintk()'s
 544  */
 545 char * SVCFH_fmt(struct svc_fh *fhp)
 546 {
 547         struct knfsd_fh *fh = &fhp->fh_handle;
 548
 549         static char buf[80];
 550         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 551                 fh->fh_size,
 552                 fh->fh_base.fh_pad[0],
 553                 fh->fh_base.fh_pad[1],
 554                 fh->fh_base.fh_pad[2],
 555                 fh->fh_base.fh_pad[3],
 556                 fh->fh_base.fh_pad[4],
 557                 fh->fh_base.fh_pad[5]);
 558         return buf;
 559 }
 560
 561 enum fsid_source fsid_source(struct svc_fh *fhp)
 562 {
 563         if (fhp->fh_handle.fh_version != 1)
 564                 return FSIDSOURCE_DEV;
 565         switch(fhp->fh_handle.fh_fsid_type) {
 566         case FSID_DEV:
 567         case FSID_ENCODE_DEV:
 568         case FSID_MAJOR_MINOR:
 569                 if (fhp->fh_export->ex_dentry->d_inode->i_sb->s_type->fs_flags
 570                     & FS_REQUIRES_DEV)
 571                         return FSIDSOURCE_DEV;
 572                 break;
 573         case FSID_NUM:
 574                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 575                         return FSIDSOURCE_FSID;
 576                 break;
 577         default:
 578                 break;
 579         }
 580         /* either a UUID type filehandle, or the filehandle doesn't
 581          * match the export.
 582          */
 583         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 584                 return FSIDSOURCE_FSID;
 585         if (fhp->fh_export->ex_uuid)
 586                 return FSIDSOURCE_UUID;
 587         return FSIDSOURCE_DEV;
 588 }