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/smp_lock.h>
  14 #include <linux/fs.h>
  15 #include <linux/unistd.h>
  16 #include <linux/string.h>
  17 #include <linux/stat.h>
  18 #include <linux/dcache.h>
  19 #include <linux/mount.h>
  20
  21 #include <linux/sunrpc/clnt.h>
  22 #include <linux/sunrpc/svc.h>
  23 #include <linux/nfsd/nfsd.h>
  24
  25 #define NFSDDBG_FACILITY                NFSDDBG_FH
  26
  27
  28 static int nfsd_nr_verified;
  29 static int nfsd_nr_put;
  30
  31 extern struct export_operations export_op_default;
  32
  33 #define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
  34
  35 /*
  36  * our acceptability function.
  37  * if NOSUBTREECHECK, accept anything
  38  * if not, require that we can walk up to exp->ex_dentry
  39  * doing some checks on the 'x' bits
  40  */
  41 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  42 {
  43         struct svc_export *exp = expv;
  44         int rv;
  45         struct dentry *tdentry;
  46         struct dentry *parent;
  47
  48         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  49                 return 1;
  50
  51         tdentry = dget(dentry);
  52         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
  53                 /* make sure parents give x permission to user */
  54                 int err;
  55                 parent = dget_parent(tdentry);
  56                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  57                 if (err < 0) {
  58                         dput(parent);
  59                         break;
  60                 }
  61                 dput(tdentry);
  62                 tdentry = parent;
  63         }
  64         if (tdentry != exp->ex_dentry)
  65                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  66         rv = (tdentry == exp->ex_dentry);
  67         dput(tdentry);
  68         return rv;
  69 }
  70
  71 /* Type check. The correct error return for type mismatches does not seem to be
  72  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  73  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  74  * the write call).
  75  */
  76 static inline __be32
  77 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  78 {
  79         /* Type can be negative when creating hardlinks - not to a dir */
  80         if (type > 0 && (mode & S_IFMT) != type) {
  81                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  82                         return nfserr_symlink;
  83                 else if (type == S_IFDIR)
  84                         return nfserr_notdir;
  85                 else if ((mode & S_IFMT) == S_IFDIR)
  86                         return nfserr_isdir;
  87                 else
  88                         return nfserr_inval;
  89         }
  90         if (type < 0 && (mode & S_IFMT) == -type) {
  91                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  92                         return nfserr_symlink;
  93                 else if (type == -S_IFDIR)
  94                         return nfserr_isdir;
  95                 else
  96                         return nfserr_notdir;
  97         }
  98         return 0;
  99 }
 100
 101 /*
 102  * Perform sanity checks on the dentry in a client's file handle.
 103  *
 104  * Note that the file handle dentry may need to be freed even after
 105  * an error return.
 106  *
 107  * This is only called at the start of an nfsproc call, so fhp points to
 108  * a svc_fh which is all 0 except for the over-the-wire file handle.
 109  */
 110 __be32
 111 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 112 {
 113         struct knfsd_fh *fh = &fhp->fh_handle;
 114         struct svc_export *exp = NULL;
 115         struct dentry   *dentry;
 116         __be32          error = 0;
 117
 118         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 119
 120         if (!fhp->fh_dentry) {
 121                 __u32 *datap=NULL;
 122                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 123                 int fileid_type;
 124                 int data_left = fh->fh_size/4;
 125
 126                 error = nfserr_stale;
 127                 if (rqstp->rq_client == NULL)
 128                         goto out;
 129                 if (rqstp->rq_vers > 2)
 130                         error = nfserr_badhandle;
 131                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 132                         return nfserr_nofilehandle;
 133
 134                 if (fh->fh_version == 1) {
 135                         int len;
 136                         datap = fh->fh_auth;
 137                         if (--data_left<0) goto out;
 138                         switch (fh->fh_auth_type) {
 139                         case 0: break;
 140                         default: goto out;
 141                         }
 142                         len = key_len(fh->fh_fsid_type) / 4;
 143                         if (len == 0) goto out;
 144                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 145                                 /* deprecated, convert to type 3 */
 146                                 len = key_len(FSID_ENCODE_DEV)/4;
 147                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 148                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 149                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 150                         }
 151                         if ((data_left -= len)<0) goto out;
 152                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
 153                         datap += len;
 154                 } else {
 155                         dev_t xdev;
 156                         ino_t xino;
 157                         if (fh->fh_size != NFS_FHSIZE)
 158                                 goto out;
 159                         /* assume old filehandle format */
 160                         xdev = old_decode_dev(fh->ofh_xdev);
 161                         xino = u32_to_ino_t(fh->ofh_xino);
 162                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 163                         exp = exp_find(rqstp->rq_client, FSID_DEV, tfh,
 164                                        &rqstp->rq_chandle);
 165                 }
 166
 167                 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
 168                                 || PTR_ERR(exp) == -ETIMEDOUT)) {
 169                         error = nfserrno(PTR_ERR(exp));
 170                         goto out;
 171                 }
 172
 173                 error = nfserr_stale;
 174                 if (!exp || IS_ERR(exp))
 175                         goto out;
 176
 177                 /* Check if the request originated from a secure port. */
 178                 error = nfserr_perm;
 179                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 180                         char buf[RPC_MAX_ADDRBUFLEN];
 181                         printk(KERN_WARNING
 182                                "nfsd: request from insecure port %s!\n",
 183                                svc_print_addr(rqstp, buf, sizeof(buf)));
 184                         goto out;
 185                 }
 186
 187                 /* Set user creds for this exportpoint */
 188                 error = nfserrno(nfsd_setuser(rqstp, exp));
 189                 if (error)
 190                         goto out;
 191
 192                 /*
 193                  * Look up the dentry using the NFS file handle.
 194                  */
 195                 error = nfserr_stale;
 196                 if (rqstp->rq_vers > 2)
 197                         error = nfserr_badhandle;
 198
 199                 if (fh->fh_version != 1) {
 200                         tfh[0] = fh->ofh_ino;
 201                         tfh[1] = fh->ofh_generation;
 202                         tfh[2] = fh->ofh_dirino;
 203                         datap = tfh;
 204                         data_left = 3;
 205                         if (fh->ofh_dirino == 0)
 206                                 fileid_type = 1;
 207                         else
 208                                 fileid_type = 2;
 209                 } else
 210                         fileid_type = fh->fh_fileid_type;
 211
 212                 if (fileid_type == 0)
 213                         dentry = dget(exp->ex_dentry);
 214                 else {
 215                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 216                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 217                                                      datap, data_left,
 218                                                      fileid_type,
 219                                                      nfsd_acceptable, exp);
 220                 }
 221                 if (dentry == NULL)
 222                         goto out;
 223                 if (IS_ERR(dentry)) {
 224                         if (PTR_ERR(dentry) != -EINVAL)
 225                                 error = nfserrno(PTR_ERR(dentry));
 226                         goto out;
 227                 }
 228
 229                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 230                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 231                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 232                                dentry->d_parent->d_name.name, dentry->d_name.name);
 233                 }
 234
 235                 fhp->fh_dentry = dentry;
 236                 fhp->fh_export = exp;
 237                 nfsd_nr_verified++;
 238         } else {
 239                 /* just rechecking permissions
 240                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 241                  */
 242                 dprintk("nfsd: fh_verify - just checking\n");
 243                 dentry = fhp->fh_dentry;
 244                 exp = fhp->fh_export;
 245                 /* Set user creds for this exportpoint; necessary even
 246                  * in the "just checking" case because this may be a
 247                  * filehandle that was created by fh_compose, and that
 248                  * is about to be used in another nfsv4 compound
 249                  * operation */
 250                 error = nfserrno(nfsd_setuser(rqstp, exp));
 251                 if (error)
 252                         goto out;
 253         }
 254         cache_get(&exp->h);
 255
 256
 257         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 258         if (error)
 259                 goto out;
 260
 261         /* Finally, check access permissions. */
 262         error = nfsd_permission(exp, dentry, access);
 263
 264         if (error) {
 265                 dprintk("fh_verify: %s/%s permission failure, "
 266                         "acc=%x, error=%d\n",
 267                         dentry->d_parent->d_name.name,
 268                         dentry->d_name.name,
 269                         access, ntohl(error));
 270         }
 271 out:
 272         if (exp && !IS_ERR(exp))
 273                 exp_put(exp);
 274         if (error == nfserr_stale)
 275                 nfsdstats.fh_stale++;
 276         return error;
 277 }
 278
 279
 280 /*
 281  * Compose a file handle for an NFS reply.
 282  *
 283  * Note that when first composed, the dentry may not yet have
 284  * an inode.  In this case a call to fh_update should be made
 285  * before the fh goes out on the wire ...
 286  */
 287 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 288                              __u32 *datap, int *maxsize)
 289 {
 290         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 291
 292         if (dentry == exp->ex_dentry) {
 293                 *maxsize = 0;
 294                 return 0;
 295         }
 296
 297         return CALL(nop,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 = 1;
 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         if (ref_fh && ref_fh->fh_export == exp) {
 346                 version = ref_fh->fh_handle.fh_version;
 347                 if (version == 0xca)
 348                         fsid_type = FSID_DEV;
 349                 else
 350                         fsid_type = ref_fh->fh_handle.fh_fsid_type;
 351                 /* We know this version/type works for this export
 352                  * so there is no need for further checks.
 353                  */
 354         } else if (exp->ex_uuid) {
 355                 if (fhp->fh_maxsize >= 64) {
 356                         if (root_export)
 357                                 fsid_type = FSID_UUID16;
 358                         else
 359                                 fsid_type = FSID_UUID16_INUM;
 360                 } else {
 361                         if (root_export)
 362                                 fsid_type = FSID_UUID8;
 363                         else
 364                                 fsid_type = FSID_UUID4_INUM;
 365                 }
 366         } else if (exp->ex_flags & NFSEXP_FSID)
 367                 fsid_type = FSID_NUM;
 368         else if (!old_valid_dev(ex_dev))
 369                 /* for newer device numbers, we must use a newer fsid format */
 370                 fsid_type = FSID_ENCODE_DEV;
 371         else
 372                 fsid_type = FSID_DEV;
 373
 374         if (ref_fh == fhp)
 375                 fh_put(ref_fh);
 376
 377         if (fhp->fh_locked || fhp->fh_dentry) {
 378                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 379                        parent->d_name.name, dentry->d_name.name);
 380         }
 381         if (fhp->fh_maxsize < NFS_FHSIZE)
 382                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 383                        fhp->fh_maxsize,
 384                        parent->d_name.name, dentry->d_name.name);
 385
 386         fhp->fh_dentry = dget(dentry); /* our internal copy */
 387         fhp->fh_export = exp;
 388         cache_get(&exp->h);
 389
 390         if (version == 0xca) {
 391                 /* old style filehandle please */
 392                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 393                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 394                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 395                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 396                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 397                 fhp->fh_handle.ofh_xino =
 398                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 399                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 400                 if (inode)
 401                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 402         } else {
 403                 int len;
 404                 fhp->fh_handle.fh_version = 1;
 405                 fhp->fh_handle.fh_auth_type = 0;
 406                 datap = fhp->fh_handle.fh_auth+0;
 407                 fhp->fh_handle.fh_fsid_type = fsid_type;
 408                 mk_fsid(fsid_type, datap, ex_dev,
 409                         exp->ex_dentry->d_inode->i_ino,
 410                         exp->ex_fsid, exp->ex_uuid);
 411
 412                 len = key_len(fsid_type);
 413                 datap += len/4;
 414                 fhp->fh_handle.fh_size = 4 + len;
 415
 416                 if (inode) {
 417                         int size = (fhp->fh_maxsize-len-4)/4;
 418                         fhp->fh_handle.fh_fileid_type =
 419                                 _fh_update(dentry, exp, datap, &size);
 420                         fhp->fh_handle.fh_size += size*4;
 421                 }
 422                 if (fhp->fh_handle.fh_fileid_type == 255)
 423                         return nfserr_opnotsupp;
 424         }
 425
 426         nfsd_nr_verified++;
 427         return 0;
 428 }
 429
 430 /*
 431  * Update file handle information after changing a dentry.
 432  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 433  */
 434 __be32
 435 fh_update(struct svc_fh *fhp)
 436 {
 437         struct dentry *dentry;
 438         __u32 *datap;
 439
 440         if (!fhp->fh_dentry)
 441                 goto out_bad;
 442
 443         dentry = fhp->fh_dentry;
 444         if (!dentry->d_inode)
 445                 goto out_negative;
 446         if (fhp->fh_handle.fh_version != 1) {
 447                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 448         } else {
 449                 int size;
 450                 if (fhp->fh_handle.fh_fileid_type != 0)
 451                         goto out;
 452                 datap = fhp->fh_handle.fh_auth+
 453                         fhp->fh_handle.fh_size/4 -1;
 454                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 455                 fhp->fh_handle.fh_fileid_type =
 456                         _fh_update(dentry, fhp->fh_export, datap, &size);
 457                 fhp->fh_handle.fh_size += size*4;
 458                 if (fhp->fh_handle.fh_fileid_type == 255)
 459                         return nfserr_opnotsupp;
 460         }
 461 out:
 462         return 0;
 463
 464 out_bad:
 465         printk(KERN_ERR "fh_update: fh not verified!\n");
 466         goto out;
 467 out_negative:
 468         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 469                 dentry->d_parent->d_name.name, dentry->d_name.name);
 470         goto out;
 471 }
 472
 473 /*
 474  * Release a file handle.
 475  */
 476 void
 477 fh_put(struct svc_fh *fhp)
 478 {
 479         struct dentry * dentry = fhp->fh_dentry;
 480         struct svc_export * exp = fhp->fh_export;
 481         if (dentry) {
 482                 fh_unlock(fhp);
 483                 fhp->fh_dentry = NULL;
 484                 dput(dentry);
 485 #ifdef CONFIG_NFSD_V3
 486                 fhp->fh_pre_saved = 0;
 487                 fhp->fh_post_saved = 0;
 488 #endif
 489                 nfsd_nr_put++;
 490         }
 491         if (exp) {
 492                 cache_put(&exp->h, &svc_export_cache);
 493                 fhp->fh_export = NULL;
 494         }
 495         return;
 496 }
 497
 498 /*
 499  * Shorthand for dprintk()'s
 500  */
 501 char * SVCFH_fmt(struct svc_fh *fhp)
 502 {
 503         struct knfsd_fh *fh = &fhp->fh_handle;
 504
 505         static char buf[80];
 506         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 507                 fh->fh_size,
 508                 fh->fh_base.fh_pad[0],
 509                 fh->fh_base.fh_pad[1],
 510                 fh->fh_base.fh_pad[2],
 511                 fh->fh_base.fh_pad[3],
 512                 fh->fh_base.fh_pad[4],
 513                 fh->fh_base.fh_pad[5]);
 514         return buf;
 515 }
 516
 517 enum fsid_source fsid_source(struct svc_fh *fhp)
 518 {
 519         if (fhp->fh_handle.fh_version != 1)
 520                 return FSIDSOURCE_DEV;
 521         switch(fhp->fh_handle.fh_fsid_type) {
 522         case FSID_DEV:
 523         case FSID_ENCODE_DEV:
 524         case FSID_MAJOR_MINOR:
 525                 return FSIDSOURCE_DEV;
 526         case FSID_NUM:
 527                 return FSIDSOURCE_FSID;
 528         default:
 529                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 530                         return FSIDSOURCE_FSID;
 531                 else
 532                         return FSIDSOURCE_UUID;
 533         }
 534 }