SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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/sched.h>
  13 #include <linux/slab.h>
  14 #include <linux/smp_lock.h>
  15 #include <linux/fs.h>
  16 #include <linux/unistd.h>
  17 #include <linux/string.h>
  18 #include <linux/stat.h>
  19 #include <linux/dcache.h>
  20 #include <linux/mount.h>
  21 #include <asm/pgtable.h>
  22
  23 #include <linux/sunrpc/clnt.h>
  24 #include <linux/sunrpc/svc.h>
  25 #include <linux/nfsd/nfsd.h>
  26
  27 #define NFSDDBG_FACILITY                NFSDDBG_FH
  28
  29
  30 static int nfsd_nr_verified;
  31 static int nfsd_nr_put;
  32
  33 extern struct export_operations export_op_default;
  34
  35 #define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
  36
  37 /*
  38  * our acceptability function.
  39  * if NOSUBTREECHECK, accept anything
  40  * if not, require that we can walk up to exp->ex_dentry
  41  * doing some checks on the 'x' bits
  42  */
  43 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  44 {
  45         struct svc_export *exp = expv;
  46         int rv;
  47         struct dentry *tdentry;
  48         struct dentry *parent;
  49
  50         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  51                 return 1;
  52
  53         tdentry = dget(dentry);
  54         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
  55                 /* make sure parents give x permission to user */
  56                 int err;
  57                 parent = dget_parent(tdentry);
  58                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  59                 if (err < 0) {
  60                         dput(parent);
  61                         break;
  62                 }
  63                 dput(tdentry);
  64                 tdentry = parent;
  65         }
  66         if (tdentry != exp->ex_dentry)
  67                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  68         rv = (tdentry == exp->ex_dentry);
  69         dput(tdentry);
  70         return rv;
  71 }
  72
  73 /* Type check. The correct error return for type mismatches does not seem to be
  74  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  75  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  76  * the write call).
  77  */
  78 static inline __be32
  79 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  80 {
  81         /* Type can be negative when creating hardlinks - not to a dir */
  82         if (type > 0 && (mode & S_IFMT) != type) {
  83                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  84                         return nfserr_symlink;
  85                 else if (type == S_IFDIR)
  86                         return nfserr_notdir;
  87                 else if ((mode & S_IFMT) == S_IFDIR)
  88                         return nfserr_isdir;
  89                 else
  90                         return nfserr_inval;
  91         }
  92         if (type < 0 && (mode & S_IFMT) == -type) {
  93                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  94                         return nfserr_symlink;
  95                 else if (type == -S_IFDIR)
  96                         return nfserr_isdir;
  97                 else
  98                         return nfserr_notdir;
  99         }
 100         return 0;
 101 }
 102
 103 /*
 104  * Perform sanity checks on the dentry in a client's file handle.
 105  *
 106  * Note that the file handle dentry may need to be freed even after
 107  * an error return.
 108  *
 109  * This is only called at the start of an nfsproc call, so fhp points to
 110  * a svc_fh which is all 0 except for the over-the-wire file handle.
 111  */
 112 __be32
 113 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 114 {
 115         struct knfsd_fh *fh = &fhp->fh_handle;
 116         struct svc_export *exp = NULL;
 117         struct dentry   *dentry;
 118         __be32          error = 0;
 119
 120         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 121
 122         if (!fhp->fh_dentry) {
 123                 __u32 *datap=NULL;
 124                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 125                 int fileid_type;
 126                 int data_left = fh->fh_size/4;
 127
 128                 error = nfserr_stale;
 129                 if (rqstp->rq_client == NULL)
 130                         goto out;
 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                         datap = fh->fh_auth;
 139                         if (--data_left<0) goto out;
 140                         switch (fh->fh_auth_type) {
 141                         case 0: break;
 142                         default: goto out;
 143                         }
 144                         len = key_len(fh->fh_fsid_type) / 4;
 145                         if (len == 0) goto out;
 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                         if ((data_left -= len)<0) goto out;
 154                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
 155                         datap += len;
 156                 } else {
 157                         dev_t xdev;
 158                         ino_t xino;
 159                         if (fh->fh_size != NFS_FHSIZE)
 160                                 goto out;
 161                         /* assume old filehandle format */
 162                         xdev = old_decode_dev(fh->ofh_xdev);
 163                         xino = u32_to_ino_t(fh->ofh_xino);
 164                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 165                         exp = exp_find(rqstp->rq_client, FSID_DEV, tfh,
 166                                        &rqstp->rq_chandle);
 167                 }
 168
 169                 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
 170                                 || PTR_ERR(exp) == -ETIMEDOUT)) {
 171                         error = nfserrno(PTR_ERR(exp));
 172                         goto out;
 173                 }
 174
 175                 error = nfserr_stale;
 176                 if (!exp || IS_ERR(exp))
 177                         goto out;
 178
 179                 /* Check if the request originated from a secure port. */
 180                 error = nfserr_perm;
 181                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 182                         char buf[RPC_MAX_ADDRBUFLEN];
 183                         printk(KERN_WARNING
 184                                "nfsd: request from insecure port %s!\n",
 185                                svc_print_addr(rqstp, buf, sizeof(buf)));
 186                         goto out;
 187                 }
 188
 189                 /* Set user creds for this exportpoint */
 190                 error = nfserrno(nfsd_setuser(rqstp, exp));
 191                 if (error)
 192                         goto out;
 193
 194                 /*
 195                  * Look up the dentry using the NFS file handle.
 196                  */
 197                 error = nfserr_stale;
 198                 if (rqstp->rq_vers > 2)
 199                         error = nfserr_badhandle;
 200
 201                 if (fh->fh_version != 1) {
 202                         tfh[0] = fh->ofh_ino;
 203                         tfh[1] = fh->ofh_generation;
 204                         tfh[2] = fh->ofh_dirino;
 205                         datap = tfh;
 206                         data_left = 3;
 207                         if (fh->ofh_dirino == 0)
 208                                 fileid_type = 1;
 209                         else
 210                                 fileid_type = 2;
 211                 } else
 212                         fileid_type = fh->fh_fileid_type;
 213
 214                 if (fileid_type == 0)
 215                         dentry = dget(exp->ex_dentry);
 216                 else {
 217                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 218                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 219                                                      datap, data_left,
 220                                                      fileid_type,
 221                                                      nfsd_acceptable, exp);
 222                 }
 223                 if (dentry == NULL)
 224                         goto out;
 225                 if (IS_ERR(dentry)) {
 226                         if (PTR_ERR(dentry) != -EINVAL)
 227                                 error = nfserrno(PTR_ERR(dentry));
 228                         goto out;
 229                 }
 230
 231                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 232                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 233                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 234                                dentry->d_parent->d_name.name, dentry->d_name.name);
 235                 }
 236
 237                 fhp->fh_dentry = dentry;
 238                 fhp->fh_export = exp;
 239                 nfsd_nr_verified++;
 240         } else {
 241                 /* just rechecking permissions
 242                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 243                  */
 244                 dprintk("nfsd: fh_verify - just checking\n");
 245                 dentry = fhp->fh_dentry;
 246                 exp = fhp->fh_export;
 247                 /* Set user creds for this exportpoint; necessary even
 248                  * in the "just checking" case because this may be a
 249                  * filehandle that was created by fh_compose, and that
 250                  * is about to be used in another nfsv4 compound
 251                  * operation */
 252                 error = nfserrno(nfsd_setuser(rqstp, exp));
 253                 if (error)
 254                         goto out;
 255         }
 256         cache_get(&exp->h);
 257
 258
 259         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 260         if (error)
 261                 goto out;
 262
 263         /* Finally, check access permissions. */
 264         error = nfsd_permission(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         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 293
 294         if (dentry == exp->ex_dentry) {
 295                 *maxsize = 0;
 296                 return 0;
 297         }
 298
 299         return CALL(nop,encode_fh)(dentry, datap, maxsize,
 300                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
 301 }
 302
 303 /*
 304  * for composing old style file handles
 305  */
 306 static inline void _fh_update_old(struct dentry *dentry,
 307                                   struct svc_export *exp,
 308                                   struct knfsd_fh *fh)
 309 {
 310         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 311         fh->ofh_generation = dentry->d_inode->i_generation;
 312         if (S_ISDIR(dentry->d_inode->i_mode) ||
 313             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 314                 fh->ofh_dirino = 0;
 315 }
 316
 317 __be32
 318 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 319            struct svc_fh *ref_fh)
 320 {
 321         /* ref_fh is a reference file handle.
 322          * if it is non-null and for the same filesystem, then we should compose
 323          * a filehandle which is of the same version, where possible.
 324          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 325          * Then create a 32byte filehandle using nfs_fhbase_old
 326          *
 327          */
 328
 329         u8 version = 1;
 330         u8 fsid_type = 0;
 331         struct inode * inode = dentry->d_inode;
 332         struct dentry *parent = dentry->d_parent;
 333         __u32 *datap;
 334         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 335         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 336
 337         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 338                 MAJOR(ex_dev), MINOR(ex_dev),
 339                 (long) exp->ex_dentry->d_inode->i_ino,
 340                 parent->d_name.name, dentry->d_name.name,
 341                 (inode ? inode->i_ino : 0));
 342
 343         /* Choose filehandle version and fsid type based on
 344          * the reference filehandle (if it is in the same export)
 345          * or the export options.
 346          */
 347         if (ref_fh && ref_fh->fh_export == exp) {
 348                 version = ref_fh->fh_handle.fh_version;
 349                 if (version == 0xca)
 350                         fsid_type = FSID_DEV;
 351                 else
 352                         fsid_type = ref_fh->fh_handle.fh_fsid_type;
 353                 /* We know this version/type works for this export
 354                  * so there is no need for further checks.
 355                  */
 356         } else if (exp->ex_uuid) {
 357                 if (fhp->fh_maxsize >= 64) {
 358                         if (root_export)
 359                                 fsid_type = FSID_UUID16;
 360                         else
 361                                 fsid_type = FSID_UUID16_INUM;
 362                 } else {
 363                         if (root_export)
 364                                 fsid_type = FSID_UUID8;
 365                         else
 366                                 fsid_type = FSID_UUID4_INUM;
 367                 }
 368         } else if (exp->ex_flags & NFSEXP_FSID)
 369                 fsid_type = FSID_NUM;
 370         else if (!old_valid_dev(ex_dev))
 371                 /* for newer device numbers, we must use a newer fsid format */
 372                 fsid_type = FSID_ENCODE_DEV;
 373         else
 374                 fsid_type = FSID_DEV;
 375
 376         if (ref_fh == fhp)
 377                 fh_put(ref_fh);
 378
 379         if (fhp->fh_locked || fhp->fh_dentry) {
 380                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 381                        parent->d_name.name, dentry->d_name.name);
 382         }
 383         if (fhp->fh_maxsize < NFS_FHSIZE)
 384                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 385                        fhp->fh_maxsize,
 386                        parent->d_name.name, dentry->d_name.name);
 387
 388         fhp->fh_dentry = dget(dentry); /* our internal copy */
 389         fhp->fh_export = exp;
 390         cache_get(&exp->h);
 391
 392         if (version == 0xca) {
 393                 /* old style filehandle please */
 394                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 395                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 396                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 397                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 398                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 399                 fhp->fh_handle.ofh_xino =
 400                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 401                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 402                 if (inode)
 403                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 404         } else {
 405                 int len;
 406                 fhp->fh_handle.fh_version = 1;
 407                 fhp->fh_handle.fh_auth_type = 0;
 408                 datap = fhp->fh_handle.fh_auth+0;
 409                 fhp->fh_handle.fh_fsid_type = fsid_type;
 410                 mk_fsid(fsid_type, datap, ex_dev,
 411                         exp->ex_dentry->d_inode->i_ino,
 412                         exp->ex_fsid, exp->ex_uuid);
 413
 414                 len = key_len(fsid_type);
 415                 datap += len/4;
 416                 fhp->fh_handle.fh_size = 4 + len;
 417
 418                 if (inode) {
 419                         int size = (fhp->fh_maxsize-len-4)/4;
 420                         fhp->fh_handle.fh_fileid_type =
 421                                 _fh_update(dentry, exp, datap, &size);
 422                         fhp->fh_handle.fh_size += size*4;
 423                 }
 424                 if (fhp->fh_handle.fh_fileid_type == 255)
 425                         return nfserr_opnotsupp;
 426         }
 427
 428         nfsd_nr_verified++;
 429         return 0;
 430 }
 431
 432 /*
 433  * Update file handle information after changing a dentry.
 434  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 435  */
 436 __be32
 437 fh_update(struct svc_fh *fhp)
 438 {
 439         struct dentry *dentry;
 440         __u32 *datap;
 441
 442         if (!fhp->fh_dentry)
 443                 goto out_bad;
 444
 445         dentry = fhp->fh_dentry;
 446         if (!dentry->d_inode)
 447                 goto out_negative;
 448         if (fhp->fh_handle.fh_version != 1) {
 449                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 450         } else {
 451                 int size;
 452                 if (fhp->fh_handle.fh_fileid_type != 0)
 453                         goto out;
 454                 datap = fhp->fh_handle.fh_auth+
 455                         fhp->fh_handle.fh_size/4 -1;
 456                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 457                 fhp->fh_handle.fh_fileid_type =
 458                         _fh_update(dentry, fhp->fh_export, datap, &size);
 459                 fhp->fh_handle.fh_size += size*4;
 460                 if (fhp->fh_handle.fh_fileid_type == 255)
 461                         return nfserr_opnotsupp;
 462         }
 463 out:
 464         return 0;
 465
 466 out_bad:
 467         printk(KERN_ERR "fh_update: fh not verified!\n");
 468         goto out;
 469 out_negative:
 470         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 471                 dentry->d_parent->d_name.name, dentry->d_name.name);
 472         goto out;
 473 }
 474
 475 /*
 476  * Release a file handle.
 477  */
 478 void
 479 fh_put(struct svc_fh *fhp)
 480 {
 481         struct dentry * dentry = fhp->fh_dentry;
 482         struct svc_export * exp = fhp->fh_export;
 483         if (dentry) {
 484                 fh_unlock(fhp);
 485                 fhp->fh_dentry = NULL;
 486                 dput(dentry);
 487 #ifdef CONFIG_NFSD_V3
 488                 fhp->fh_pre_saved = 0;
 489                 fhp->fh_post_saved = 0;
 490 #endif
 491                 nfsd_nr_put++;
 492         }
 493         if (exp) {
 494                 cache_put(&exp->h, &svc_export_cache);
 495                 fhp->fh_export = NULL;
 496         }
 497         return;
 498 }
 499
 500 /*
 501  * Shorthand for dprintk()'s
 502  */
 503 char * SVCFH_fmt(struct svc_fh *fhp)
 504 {
 505         struct knfsd_fh *fh = &fhp->fh_handle;
 506
 507         static char buf[80];
 508         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 509                 fh->fh_size,
 510                 fh->fh_base.fh_pad[0],
 511                 fh->fh_base.fh_pad[1],
 512                 fh->fh_base.fh_pad[2],
 513                 fh->fh_base.fh_pad[3],
 514                 fh->fh_base.fh_pad[4],
 515                 fh->fh_base.fh_pad[5]);
 516         return buf;
 517 }
 518
 519 enum fsid_source fsid_source(struct svc_fh *fhp)
 520 {
 521         if (fhp->fh_handle.fh_version != 1)
 522                 return FSIDSOURCE_DEV;
 523         switch(fhp->fh_handle.fh_fsid_type) {
 524         case FSID_DEV:
 525         case FSID_ENCODE_DEV:
 526         case FSID_MAJOR_MINOR:
 527                 return FSIDSOURCE_DEV;
 528         case FSID_NUM:
 529                 return FSIDSOURCE_FSID;
 530         default:
 531                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 532                         return FSIDSOURCE_FSID;
 533                 else
 534                         return FSIDSOURCE_UUID;
 535         }
 536 }