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 #include "auth.h"
  26
  27 #define NFSDDBG_FACILITY                NFSDDBG_FH
  28
  29
  30 static int nfsd_nr_verified;
  31 static int nfsd_nr_put;
  32
  33 /*
  34  * our acceptability function.
  35  * if NOSUBTREECHECK, accept anything
  36  * if not, require that we can walk up to exp->ex_dentry
  37  * doing some checks on the 'x' bits
  38  */
  39 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  40 {
  41         struct svc_export *exp = expv;
  42         int rv;
  43         struct dentry *tdentry;
  44         struct dentry *parent;
  45
  46         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  47                 return 1;
  48
  49         tdentry = dget(dentry);
  50         while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
  51                 /* make sure parents give x permission to user */
  52                 int err;
  53                 parent = dget_parent(tdentry);
  54                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  55                 if (err < 0) {
  56                         dput(parent);
  57                         break;
  58                 }
  59                 dput(tdentry);
  60                 tdentry = parent;
  61         }
  62         if (tdentry != exp->ex_path.dentry)
  63                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  64         rv = (tdentry == exp->ex_path.dentry);
  65         dput(tdentry);
  66         return rv;
  67 }
  68
  69 /* Type check. The correct error return for type mismatches does not seem to be
  70  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  71  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  72  * the write call).
  73  */
  74 static inline __be32
  75 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  76 {
  77         /* Type can be negative when creating hardlinks - not to a dir */
  78         if (type > 0 && (mode & S_IFMT) != type) {
  79                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  80                         return nfserr_symlink;
  81                 else if (type == S_IFDIR)
  82                         return nfserr_notdir;
  83                 else if ((mode & S_IFMT) == S_IFDIR)
  84                         return nfserr_isdir;
  85                 else
  86                         return nfserr_inval;
  87         }
  88         if (type < 0 && (mode & S_IFMT) == -type) {
  89                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  90                         return nfserr_symlink;
  91                 else if (type == -S_IFDIR)
  92                         return nfserr_isdir;
  93                 else
  94                         return nfserr_notdir;
  95         }
  96         return 0;
  97 }
  98
  99 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
 100                                           struct svc_export *exp)
 101 {
 102         /* Check if the request originated from a secure port. */
 103         if (!rqstp->rq_secure && EX_SECURE(exp)) {
 104                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 105                 dprintk(KERN_WARNING
 106                        "nfsd: request from insecure port %s!\n",
 107                        svc_print_addr(rqstp, buf, sizeof(buf)));
 108                 return nfserr_perm;
 109         }
 110
 111         /* Set user creds for this exportpoint */
 112         return nfserrno(nfsd_setuser(rqstp, exp));
 113 }
 114
 115 /*
 116  * Use the given filehandle to look up the corresponding export and
 117  * dentry.  On success, the results are used to set fh_export and
 118  * fh_dentry.
 119  */
 120 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 121 {
 122         struct knfsd_fh *fh = &fhp->fh_handle;
 123         struct fid *fid = NULL, sfid;
 124         struct svc_export *exp;
 125         struct dentry *dentry;
 126         int fileid_type;
 127         int data_left = fh->fh_size/4;
 128         __be32 error;
 129
 130         error = nfserr_stale;
 131         if (rqstp->rq_vers > 2)
 132                 error = nfserr_badhandle;
 133         if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 134                 return nfserr_nofilehandle;
 135
 136         if (fh->fh_version == 1) {
 137                 int len;
 138
 139                 if (--data_left < 0)
 140                         return error;
 141                 if (fh->fh_auth_type != 0)
 142                         return error;
 143                 len = key_len(fh->fh_fsid_type) / 4;
 144                 if (len == 0)
 145                         return error;
 146                 if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 147                         /* deprecated, convert to type 3 */
 148                         len = key_len(FSID_ENCODE_DEV)/4;
 149                         fh->fh_fsid_type = FSID_ENCODE_DEV;
 150                         fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 151                         fh->fh_fsid[1] = fh->fh_fsid[2];
 152                 }
 153                 data_left -= len;
 154                 if (data_left < 0)
 155                         return error;
 156                 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
 157                 fid = (struct fid *)(fh->fh_auth + len);
 158         } else {
 159                 __u32 tfh[2];
 160                 dev_t xdev;
 161                 ino_t xino;
 162
 163                 if (fh->fh_size != NFS_FHSIZE)
 164                         return error;
 165                 /* assume old filehandle format */
 166                 xdev = old_decode_dev(fh->ofh_xdev);
 167                 xino = u32_to_ino_t(fh->ofh_xino);
 168                 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 169                 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 170         }
 171
 172         error = nfserr_stale;
 173         if (PTR_ERR(exp) == -ENOENT)
 174                 return error;
 175
 176         if (IS_ERR(exp))
 177                 return nfserrno(PTR_ERR(exp));
 178
 179         error = nfsd_setuser_and_check_port(rqstp, exp);
 180         if (error)
 181                 goto out;
 182
 183         /*
 184          * Look up the dentry using the NFS file handle.
 185          */
 186         error = nfserr_stale;
 187         if (rqstp->rq_vers > 2)
 188                 error = nfserr_badhandle;
 189
 190         if (fh->fh_version != 1) {
 191                 sfid.i32.ino = fh->ofh_ino;
 192                 sfid.i32.gen = fh->ofh_generation;
 193                 sfid.i32.parent_ino = fh->ofh_dirino;
 194                 fid = &sfid;
 195                 data_left = 3;
 196                 if (fh->ofh_dirino == 0)
 197                         fileid_type = FILEID_INO32_GEN;
 198                 else
 199                         fileid_type = FILEID_INO32_GEN_PARENT;
 200         } else
 201                 fileid_type = fh->fh_fileid_type;
 202
 203         if (fileid_type == FILEID_ROOT)
 204                 dentry = dget(exp->ex_path.dentry);
 205         else {
 206                 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
 207                                 data_left, fileid_type,
 208                                 nfsd_acceptable, exp);
 209         }
 210         if (dentry == NULL)
 211                 goto out;
 212         if (IS_ERR(dentry)) {
 213                 if (PTR_ERR(dentry) != -EINVAL)
 214                         error = nfserrno(PTR_ERR(dentry));
 215                 goto out;
 216         }
 217
 218         if (S_ISDIR(dentry->d_inode->i_mode) &&
 219                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
 220                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 221                                 dentry->d_parent->d_name.name, dentry->d_name.name);
 222         }
 223
 224         fhp->fh_dentry = dentry;
 225         fhp->fh_export = exp;
 226         nfsd_nr_verified++;
 227         return 0;
 228 out:
 229         exp_put(exp);
 230         return error;
 231 }
 232
 233 /*
 234  * Perform sanity checks on the dentry in a client's file handle.
 235  *
 236  * Note that the file handle dentry may need to be freed even after
 237  * an error return.
 238  *
 239  * This is only called at the start of an nfsproc call, so fhp points to
 240  * a svc_fh which is all 0 except for the over-the-wire file handle.
 241  */
 242 __be32
 243 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 244 {
 245         struct svc_export *exp;
 246         struct dentry   *dentry;
 247         __be32          error;
 248
 249         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 250
 251         if (!fhp->fh_dentry) {
 252                 error = nfsd_set_fh_dentry(rqstp, fhp);
 253                 if (error)
 254                         goto out;
 255                 dentry = fhp->fh_dentry;
 256                 exp = fhp->fh_export;
 257         } else {
 258                 /*
 259                  * just rechecking permissions
 260                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create
 261                  * does as well)
 262                  */
 263                 dprintk("nfsd: fh_verify - just checking\n");
 264                 dentry = fhp->fh_dentry;
 265                 exp = fhp->fh_export;
 266                 /*
 267                  * Set user creds for this exportpoint; necessary even
 268                  * in the "just checking" case because this may be a
 269                  * filehandle that was created by fh_compose, and that
 270                  * is about to be used in another nfsv4 compound
 271                  * operation.
 272                  */
 273                 error = nfsd_setuser_and_check_port(rqstp, exp);
 274                 if (error)
 275                         goto out;
 276         }
 277
 278         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 279         if (error)
 280                 goto out;
 281
 282         if (!(access & MAY_LOCK)) {
 283                 /*
 284                  * pseudoflavor restrictions are not enforced on NLM,
 285                  * which clients virtually always use auth_sys for,
 286                  * even while using RPCSEC_GSS for NFS.
 287                  */
 288                 error = check_nfsd_access(exp, rqstp);
 289                 if (error)
 290                         goto out;
 291         }
 292
 293         /* Finally, check access permissions. */
 294         error = nfsd_permission(rqstp, exp, dentry, access);
 295
 296         if (error) {
 297                 dprintk("fh_verify: %s/%s permission failure, "
 298                         "acc=%x, error=%d\n",
 299                         dentry->d_parent->d_name.name,
 300                         dentry->d_name.name,
 301                         access, ntohl(error));
 302         }
 303 out:
 304         if (error == nfserr_stale)
 305                 nfsdstats.fh_stale++;
 306         return error;
 307 }
 308
 309
 310 /*
 311  * Compose a file handle for an NFS reply.
 312  *
 313  * Note that when first composed, the dentry may not yet have
 314  * an inode.  In this case a call to fh_update should be made
 315  * before the fh goes out on the wire ...
 316  */
 317 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 318                 struct dentry *dentry)
 319 {
 320         if (dentry != exp->ex_path.dentry) {
 321                 struct fid *fid = (struct fid *)
 322                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
 323                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 324                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 325
 326                 fhp->fh_handle.fh_fileid_type =
 327                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 328                 fhp->fh_handle.fh_size += maxsize * 4;
 329         } else {
 330                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 331         }
 332 }
 333
 334 /*
 335  * for composing old style file handles
 336  */
 337 static inline void _fh_update_old(struct dentry *dentry,
 338                                   struct svc_export *exp,
 339                                   struct knfsd_fh *fh)
 340 {
 341         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 342         fh->ofh_generation = dentry->d_inode->i_generation;
 343         if (S_ISDIR(dentry->d_inode->i_mode) ||
 344             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 345                 fh->ofh_dirino = 0;
 346 }
 347
 348 __be32
 349 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 350            struct svc_fh *ref_fh)
 351 {
 352         /* ref_fh is a reference file handle.
 353          * if it is non-null and for the same filesystem, then we should compose
 354          * a filehandle which is of the same version, where possible.
 355          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 356          * Then create a 32byte filehandle using nfs_fhbase_old
 357          *
 358          */
 359
 360         u8 version;
 361         u8 fsid_type = 0;
 362         struct inode * inode = dentry->d_inode;
 363         struct dentry *parent = dentry->d_parent;
 364         __u32 *datap;
 365         dev_t ex_dev = exp->ex_path.dentry->d_inode->i_sb->s_dev;
 366         int root_export = (exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root);
 367
 368         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 369                 MAJOR(ex_dev), MINOR(ex_dev),
 370                 (long) exp->ex_path.dentry->d_inode->i_ino,
 371                 parent->d_name.name, dentry->d_name.name,
 372                 (inode ? inode->i_ino : 0));
 373
 374         /* Choose filehandle version and fsid type based on
 375          * the reference filehandle (if it is in the same export)
 376          * or the export options.
 377          */
 378  retry:
 379         version = 1;
 380         if (ref_fh && ref_fh->fh_export == exp) {
 381                 version = ref_fh->fh_handle.fh_version;
 382                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 383
 384                 if (ref_fh == fhp)
 385                         fh_put(ref_fh);
 386                 ref_fh = NULL;
 387
 388                 switch (version) {
 389                 case 0xca:
 390                         fsid_type = FSID_DEV;
 391                         break;
 392                 case 1:
 393                         break;
 394                 default:
 395                         goto retry;
 396                 }
 397
 398                 /* Need to check that this type works for this
 399                  * export point.  As the fsid -> filesystem mapping
 400                  * was guided by user-space, there is no guarantee
 401                  * that the filesystem actually supports that fsid
 402                  * type. If it doesn't we loop around again without
 403                  * ref_fh set.
 404                  */
 405                 switch(fsid_type) {
 406                 case FSID_DEV:
 407                         if (!old_valid_dev(ex_dev))
 408                                 goto retry;
 409                         /* FALL THROUGH */
 410                 case FSID_MAJOR_MINOR:
 411                 case FSID_ENCODE_DEV:
 412                         if (!(exp->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
 413                               & FS_REQUIRES_DEV))
 414                                 goto retry;
 415                         break;
 416                 case FSID_NUM:
 417                         if (! (exp->ex_flags & NFSEXP_FSID))
 418                                 goto retry;
 419                         break;
 420                 case FSID_UUID8:
 421                 case FSID_UUID16:
 422                         if (!root_export)
 423                                 goto retry;
 424                         /* fall through */
 425                 case FSID_UUID4_INUM:
 426                 case FSID_UUID16_INUM:
 427                         if (exp->ex_uuid == NULL)
 428                                 goto retry;
 429                         break;
 430                 }
 431         } else if (exp->ex_uuid) {
 432                 if (fhp->fh_maxsize >= 64) {
 433                         if (root_export)
 434                                 fsid_type = FSID_UUID16;
 435                         else
 436                                 fsid_type = FSID_UUID16_INUM;
 437                 } else {
 438                         if (root_export)
 439                                 fsid_type = FSID_UUID8;
 440                         else
 441                                 fsid_type = FSID_UUID4_INUM;
 442                 }
 443         } else if (exp->ex_flags & NFSEXP_FSID)
 444                 fsid_type = FSID_NUM;
 445         else if (!old_valid_dev(ex_dev))
 446                 /* for newer device numbers, we must use a newer fsid format */
 447                 fsid_type = FSID_ENCODE_DEV;
 448         else
 449                 fsid_type = FSID_DEV;
 450
 451         if (ref_fh == fhp)
 452                 fh_put(ref_fh);
 453
 454         if (fhp->fh_locked || fhp->fh_dentry) {
 455                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 456                        parent->d_name.name, dentry->d_name.name);
 457         }
 458         if (fhp->fh_maxsize < NFS_FHSIZE)
 459                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 460                        fhp->fh_maxsize,
 461                        parent->d_name.name, dentry->d_name.name);
 462
 463         fhp->fh_dentry = dget(dentry); /* our internal copy */
 464         fhp->fh_export = exp;
 465         cache_get(&exp->h);
 466
 467         if (version == 0xca) {
 468                 /* old style filehandle please */
 469                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 470                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 471                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 472                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 473                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 474                 fhp->fh_handle.ofh_xino =
 475                         ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
 476                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 477                 if (inode)
 478                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 479         } else {
 480                 int len;
 481                 fhp->fh_handle.fh_version = 1;
 482                 fhp->fh_handle.fh_auth_type = 0;
 483                 datap = fhp->fh_handle.fh_auth+0;
 484                 fhp->fh_handle.fh_fsid_type = fsid_type;
 485                 mk_fsid(fsid_type, datap, ex_dev,
 486                         exp->ex_path.dentry->d_inode->i_ino,
 487                         exp->ex_fsid, exp->ex_uuid);
 488
 489                 len = key_len(fsid_type);
 490                 datap += len/4;
 491                 fhp->fh_handle.fh_size = 4 + len;
 492
 493                 if (inode)
 494                         _fh_update(fhp, exp, dentry);
 495                 if (fhp->fh_handle.fh_fileid_type == 255)
 496                         return nfserr_opnotsupp;
 497         }
 498
 499         nfsd_nr_verified++;
 500         return 0;
 501 }
 502
 503 /*
 504  * Update file handle information after changing a dentry.
 505  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 506  */
 507 __be32
 508 fh_update(struct svc_fh *fhp)
 509 {
 510         struct dentry *dentry;
 511
 512         if (!fhp->fh_dentry)
 513                 goto out_bad;
 514
 515         dentry = fhp->fh_dentry;
 516         if (!dentry->d_inode)
 517                 goto out_negative;
 518         if (fhp->fh_handle.fh_version != 1) {
 519                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 520         } else {
 521                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 522                         goto out;
 523
 524                 _fh_update(fhp, fhp->fh_export, dentry);
 525                 if (fhp->fh_handle.fh_fileid_type == 255)
 526                         return nfserr_opnotsupp;
 527         }
 528 out:
 529         return 0;
 530
 531 out_bad:
 532         printk(KERN_ERR "fh_update: fh not verified!\n");
 533         goto out;
 534 out_negative:
 535         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 536                 dentry->d_parent->d_name.name, dentry->d_name.name);
 537         goto out;
 538 }
 539
 540 /*
 541  * Release a file handle.
 542  */
 543 void
 544 fh_put(struct svc_fh *fhp)
 545 {
 546         struct dentry * dentry = fhp->fh_dentry;
 547         struct svc_export * exp = fhp->fh_export;
 548         if (dentry) {
 549                 fh_unlock(fhp);
 550                 fhp->fh_dentry = NULL;
 551                 dput(dentry);
 552 #ifdef CONFIG_NFSD_V3
 553                 fhp->fh_pre_saved = 0;
 554                 fhp->fh_post_saved = 0;
 555 #endif
 556                 nfsd_nr_put++;
 557         }
 558         if (exp) {
 559                 cache_put(&exp->h, &svc_export_cache);
 560                 fhp->fh_export = NULL;
 561         }
 562         return;
 563 }
 564
 565 /*
 566  * Shorthand for dprintk()'s
 567  */
 568 char * SVCFH_fmt(struct svc_fh *fhp)
 569 {
 570         struct knfsd_fh *fh = &fhp->fh_handle;
 571
 572         static char buf[80];
 573         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 574                 fh->fh_size,
 575                 fh->fh_base.fh_pad[0],
 576                 fh->fh_base.fh_pad[1],
 577                 fh->fh_base.fh_pad[2],
 578                 fh->fh_base.fh_pad[3],
 579                 fh->fh_base.fh_pad[4],
 580                 fh->fh_base.fh_pad[5]);
 581         return buf;
 582 }
 583
 584 enum fsid_source fsid_source(struct svc_fh *fhp)
 585 {
 586         if (fhp->fh_handle.fh_version != 1)
 587                 return FSIDSOURCE_DEV;
 588         switch(fhp->fh_handle.fh_fsid_type) {
 589         case FSID_DEV:
 590         case FSID_ENCODE_DEV:
 591         case FSID_MAJOR_MINOR:
 592                 if (fhp->fh_export->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
 593                     & FS_REQUIRES_DEV)
 594                         return FSIDSOURCE_DEV;
 595                 break;
 596         case FSID_NUM:
 597                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 598                         return FSIDSOURCE_FSID;
 599                 break;
 600         default:
 601                 break;
 602         }
 603         /* either a UUID type filehandle, or the filehandle doesn't
 604          * match the export.
 605          */
 606         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 607                 return FSIDSOURCE_FSID;
 608         if (fhp->fh_export->ex_uuid)
 609                 return FSIDSOURCE_UUID;
 610         return FSIDSOURCE_DEV;
 611 }