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 #include <asm/pgtable.h>
  21
  22 #include <linux/sunrpc/clnt.h>
  23 #include <linux/sunrpc/svc.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 extern struct export_operations export_op_default;
  33
  34 #define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
  35
  36 /*
  37  * our acceptability function.
  38  * if NOSUBTREECHECK, accept anything
  39  * if not, require that we can walk up to exp->ex_dentry
  40  * doing some checks on the 'x' bits
  41  */
  42 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  43 {
  44         struct svc_export *exp = expv;
  45         int rv;
  46         struct dentry *tdentry;
  47         struct dentry *parent;
  48
  49         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  50                 return 1;
  51
  52         tdentry = dget(dentry);
  53         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
  54                 /* make sure parents give x permission to user */
  55                 int err;
  56                 parent = dget_parent(tdentry);
  57                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  58                 if (err < 0) {
  59                         dput(parent);
  60                         break;
  61                 }
  62                 dput(tdentry);
  63                 tdentry = parent;
  64         }
  65         if (tdentry != exp->ex_dentry)
  66                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  67         rv = (tdentry == exp->ex_dentry);
  68         dput(tdentry);
  69         return rv;
  70 }
  71
  72 /* Type check. The correct error return for type mismatches does not seem to be
  73  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  74  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  75  * the write call).
  76  */
  77 static inline __be32
  78 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  79 {
  80         /* Type can be negative when creating hardlinks - not to a dir */
  81         if (type > 0 && (mode & S_IFMT) != type) {
  82                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  83                         return nfserr_symlink;
  84                 else if (type == S_IFDIR)
  85                         return nfserr_notdir;
  86                 else if ((mode & S_IFMT) == S_IFDIR)
  87                         return nfserr_isdir;
  88                 else
  89                         return nfserr_inval;
  90         }
  91         if (type < 0 && (mode & S_IFMT) == -type) {
  92                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  93                         return nfserr_symlink;
  94                 else if (type == -S_IFDIR)
  95                         return nfserr_isdir;
  96                 else
  97                         return nfserr_notdir;
  98         }
  99         return 0;
 100 }
 101
 102 /*
 103  * Perform sanity checks on the dentry in a client's file handle.
 104  *
 105  * Note that the file handle dentry may need to be freed even after
 106  * an error return.
 107  *
 108  * This is only called at the start of an nfsproc call, so fhp points to
 109  * a svc_fh which is all 0 except for the over-the-wire file handle.
 110  */
 111 __be32
 112 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 113 {
 114         struct knfsd_fh *fh = &fhp->fh_handle;
 115         struct svc_export *exp = NULL;
 116         struct dentry   *dentry;
 117         __be32          error = 0;
 118
 119         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 120
 121         if (!fhp->fh_dentry) {
 122                 __u32 *datap=NULL;
 123                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 124                 int fileid_type;
 125                 int data_left = fh->fh_size/4;
 126
 127                 error = nfserr_stale;
 128                 if (rqstp->rq_client == NULL)
 129                         goto out;
 130                 if (rqstp->rq_vers > 2)
 131                         error = nfserr_badhandle;
 132                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 133                         return nfserr_nofilehandle;
 134
 135                 if (fh->fh_version == 1) {
 136                         int len;
 137                         datap = fh->fh_auth;
 138                         if (--data_left<0) goto out;
 139                         switch (fh->fh_auth_type) {
 140                         case 0: break;
 141                         default: goto out;
 142                         }
 143                         len = key_len(fh->fh_fsid_type) / 4;
 144                         if (len == 0) goto out;
 145                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 146                                 /* deprecated, convert to type 3 */
 147                                 len = key_len(FSID_ENCODE_DEV)/4;
 148                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 149                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 150                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 151                         }
 152                         if ((data_left -= len)<0) goto out;
 153                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
 154                         datap += len;
 155                 } else {
 156                         dev_t xdev;
 157                         ino_t xino;
 158                         if (fh->fh_size != NFS_FHSIZE)
 159                                 goto out;
 160                         /* assume old filehandle format */
 161                         xdev = old_decode_dev(fh->ofh_xdev);
 162                         xino = u32_to_ino_t(fh->ofh_xino);
 163                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 164                         exp = exp_find(rqstp->rq_client, FSID_DEV, tfh,
 165                                        &rqstp->rq_chandle);
 166                 }
 167
 168                 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
 169                                 || PTR_ERR(exp) == -ETIMEDOUT)) {
 170                         error = nfserrno(PTR_ERR(exp));
 171                         goto out;
 172                 }
 173
 174                 error = nfserr_stale;
 175                 if (!exp || IS_ERR(exp))
 176                         goto out;
 177
 178                 /* Check if the request originated from a secure port. */
 179                 error = nfserr_perm;
 180                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 181                         char buf[RPC_MAX_ADDRBUFLEN];
 182                         printk(KERN_WARNING
 183                                "nfsd: request from insecure port %s!\n",
 184                                svc_print_addr(rqstp, buf, sizeof(buf)));
 185                         goto out;
 186                 }
 187
 188                 /* Set user creds for this exportpoint */
 189                 error = nfserrno(nfsd_setuser(rqstp, exp));
 190                 if (error)
 191                         goto out;
 192
 193                 /*
 194                  * Look up the dentry using the NFS file handle.
 195                  */
 196                 error = nfserr_stale;
 197                 if (rqstp->rq_vers > 2)
 198                         error = nfserr_badhandle;
 199
 200                 if (fh->fh_version != 1) {
 201                         tfh[0] = fh->ofh_ino;
 202                         tfh[1] = fh->ofh_generation;
 203                         tfh[2] = fh->ofh_dirino;
 204                         datap = tfh;
 205                         data_left = 3;
 206                         if (fh->ofh_dirino == 0)
 207                                 fileid_type = 1;
 208                         else
 209                                 fileid_type = 2;
 210                 } else
 211                         fileid_type = fh->fh_fileid_type;
 212
 213                 if (fileid_type == 0)
 214                         dentry = dget(exp->ex_dentry);
 215                 else {
 216                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 217                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 218                                                      datap, data_left,
 219                                                      fileid_type,
 220                                                      nfsd_acceptable, exp);
 221                 }
 222                 if (dentry == NULL)
 223                         goto out;
 224                 if (IS_ERR(dentry)) {
 225                         if (PTR_ERR(dentry) != -EINVAL)
 226                                 error = nfserrno(PTR_ERR(dentry));
 227                         goto out;
 228                 }
 229
 230                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 231                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 232                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 233                                dentry->d_parent->d_name.name, dentry->d_name.name);
 234                 }
 235
 236                 fhp->fh_dentry = dentry;
 237                 fhp->fh_export = exp;
 238                 nfsd_nr_verified++;
 239         } else {
 240                 /* just rechecking permissions
 241                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 242                  */
 243                 dprintk("nfsd: fh_verify - just checking\n");
 244                 dentry = fhp->fh_dentry;
 245                 exp = fhp->fh_export;
 246                 /* Set user creds for this exportpoint; necessary even
 247                  * in the "just checking" case because this may be a
 248                  * filehandle that was created by fh_compose, and that
 249                  * is about to be used in another nfsv4 compound
 250                  * operation */
 251                 error = nfserrno(nfsd_setuser(rqstp, exp));
 252                 if (error)
 253                         goto out;
 254         }
 255         cache_get(&exp->h);
 256
 257
 258         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 259         if (error)
 260                 goto out;
 261
 262         /* Finally, check access permissions. */
 263         error = nfsd_permission(exp, dentry, access);
 264
 265         if (error) {
 266                 dprintk("fh_verify: %s/%s permission failure, "
 267                         "acc=%x, error=%d\n",
 268                         dentry->d_parent->d_name.name,
 269                         dentry->d_name.name,
 270                         access, ntohl(error));
 271         }
 272 out:
 273         if (exp && !IS_ERR(exp))
 274                 exp_put(exp);
 275         if (error == nfserr_stale)
 276                 nfsdstats.fh_stale++;
 277         return error;
 278 }
 279
 280
 281 /*
 282  * Compose a file handle for an NFS reply.
 283  *
 284  * Note that when first composed, the dentry may not yet have
 285  * an inode.  In this case a call to fh_update should be made
 286  * before the fh goes out on the wire ...
 287  */
 288 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 289                              __u32 *datap, int *maxsize)
 290 {
 291         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 292
 293         if (dentry == exp->ex_dentry) {
 294                 *maxsize = 0;
 295                 return 0;
 296         }
 297
 298         return CALL(nop,encode_fh)(dentry, datap, maxsize,
 299                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
 300 }
 301
 302 /*
 303  * for composing old style file handles
 304  */
 305 static inline void _fh_update_old(struct dentry *dentry,
 306                                   struct svc_export *exp,
 307                                   struct knfsd_fh *fh)
 308 {
 309         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 310         fh->ofh_generation = dentry->d_inode->i_generation;
 311         if (S_ISDIR(dentry->d_inode->i_mode) ||
 312             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 313                 fh->ofh_dirino = 0;
 314 }
 315
 316 __be32
 317 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 318            struct svc_fh *ref_fh)
 319 {
 320         /* ref_fh is a reference file handle.
 321          * if it is non-null and for the same filesystem, then we should compose
 322          * a filehandle which is of the same version, where possible.
 323          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 324          * Then create a 32byte filehandle using nfs_fhbase_old
 325          *
 326          */
 327
 328         u8 version = 1;
 329         u8 fsid_type = 0;
 330         struct inode * inode = dentry->d_inode;
 331         struct dentry *parent = dentry->d_parent;
 332         __u32 *datap;
 333         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 334         int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
 335
 336         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 337                 MAJOR(ex_dev), MINOR(ex_dev),
 338                 (long) exp->ex_dentry->d_inode->i_ino,
 339                 parent->d_name.name, dentry->d_name.name,
 340                 (inode ? inode->i_ino : 0));
 341
 342         /* Choose filehandle version and fsid type based on
 343          * the reference filehandle (if it is in the same export)
 344          * or the export options.
 345          */
 346         if (ref_fh && ref_fh->fh_export == exp) {
 347                 version = ref_fh->fh_handle.fh_version;
 348                 if (version == 0xca)
 349                         fsid_type = FSID_DEV;
 350                 else
 351                         fsid_type = ref_fh->fh_handle.fh_fsid_type;
 352                 /* We know this version/type works for this export
 353                  * so there is no need for further checks.
 354                  */
 355         } else if (exp->ex_uuid) {
 356                 if (fhp->fh_maxsize >= 64) {
 357                         if (root_export)
 358                                 fsid_type = FSID_UUID16;
 359                         else
 360                                 fsid_type = FSID_UUID16_INUM;
 361                 } else {
 362                         if (root_export)
 363                                 fsid_type = FSID_UUID8;
 364                         else
 365                                 fsid_type = FSID_UUID4_INUM;
 366                 }
 367         } else if (exp->ex_flags & NFSEXP_FSID)
 368                 fsid_type = FSID_NUM;
 369         else if (!old_valid_dev(ex_dev))
 370                 /* for newer device numbers, we must use a newer fsid format */
 371                 fsid_type = FSID_ENCODE_DEV;
 372         else
 373                 fsid_type = FSID_DEV;
 374
 375         if (ref_fh == fhp)
 376                 fh_put(ref_fh);
 377
 378         if (fhp->fh_locked || fhp->fh_dentry) {
 379                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 380                        parent->d_name.name, dentry->d_name.name);
 381         }
 382         if (fhp->fh_maxsize < NFS_FHSIZE)
 383                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 384                        fhp->fh_maxsize,
 385                        parent->d_name.name, dentry->d_name.name);
 386
 387         fhp->fh_dentry = dget(dentry); /* our internal copy */
 388         fhp->fh_export = exp;
 389         cache_get(&exp->h);
 390
 391         if (version == 0xca) {
 392                 /* old style filehandle please */
 393                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 394                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 395                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 396                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 397                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 398                 fhp->fh_handle.ofh_xino =
 399                         ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 400                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 401                 if (inode)
 402                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 403         } else {
 404                 int len;
 405                 fhp->fh_handle.fh_version = 1;
 406                 fhp->fh_handle.fh_auth_type = 0;
 407                 datap = fhp->fh_handle.fh_auth+0;
 408                 fhp->fh_handle.fh_fsid_type = fsid_type;
 409                 mk_fsid(fsid_type, datap, ex_dev,
 410                         exp->ex_dentry->d_inode->i_ino,
 411                         exp->ex_fsid, exp->ex_uuid);
 412
 413                 len = key_len(fsid_type);
 414                 datap += len/4;
 415                 fhp->fh_handle.fh_size = 4 + len;
 416
 417                 if (inode) {
 418                         int size = (fhp->fh_maxsize-len-4)/4;
 419                         fhp->fh_handle.fh_fileid_type =
 420                                 _fh_update(dentry, exp, datap, &size);
 421                         fhp->fh_handle.fh_size += size*4;
 422                 }
 423                 if (fhp->fh_handle.fh_fileid_type == 255)
 424                         return nfserr_opnotsupp;
 425         }
 426
 427         nfsd_nr_verified++;
 428         return 0;
 429 }
 430
 431 /*
 432  * Update file handle information after changing a dentry.
 433  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 434  */
 435 __be32
 436 fh_update(struct svc_fh *fhp)
 437 {
 438         struct dentry *dentry;
 439         __u32 *datap;
 440
 441         if (!fhp->fh_dentry)
 442                 goto out_bad;
 443
 444         dentry = fhp->fh_dentry;
 445         if (!dentry->d_inode)
 446                 goto out_negative;
 447         if (fhp->fh_handle.fh_version != 1) {
 448                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 449         } else {
 450                 int size;
 451                 if (fhp->fh_handle.fh_fileid_type != 0)
 452                         goto out;
 453                 datap = fhp->fh_handle.fh_auth+
 454                         fhp->fh_handle.fh_size/4 -1;
 455                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 456                 fhp->fh_handle.fh_fileid_type =
 457                         _fh_update(dentry, fhp->fh_export, datap, &size);
 458                 fhp->fh_handle.fh_size += size*4;
 459                 if (fhp->fh_handle.fh_fileid_type == 255)
 460                         return nfserr_opnotsupp;
 461         }
 462 out:
 463         return 0;
 464
 465 out_bad:
 466         printk(KERN_ERR "fh_update: fh not verified!\n");
 467         goto out;
 468 out_negative:
 469         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 470                 dentry->d_parent->d_name.name, dentry->d_name.name);
 471         goto out;
 472 }
 473
 474 /*
 475  * Release a file handle.
 476  */
 477 void
 478 fh_put(struct svc_fh *fhp)
 479 {
 480         struct dentry * dentry = fhp->fh_dentry;
 481         struct svc_export * exp = fhp->fh_export;
 482         if (dentry) {
 483                 fh_unlock(fhp);
 484                 fhp->fh_dentry = NULL;
 485                 dput(dentry);
 486 #ifdef CONFIG_NFSD_V3
 487                 fhp->fh_pre_saved = 0;
 488                 fhp->fh_post_saved = 0;
 489 #endif
 490                 nfsd_nr_put++;
 491         }
 492         if (exp) {
 493                 cache_put(&exp->h, &svc_export_cache);
 494                 fhp->fh_export = NULL;
 495         }
 496         return;
 497 }
 498
 499 /*
 500  * Shorthand for dprintk()'s
 501  */
 502 char * SVCFH_fmt(struct svc_fh *fhp)
 503 {
 504         struct knfsd_fh *fh = &fhp->fh_handle;
 505
 506         static char buf[80];
 507         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 508                 fh->fh_size,
 509                 fh->fh_base.fh_pad[0],
 510                 fh->fh_base.fh_pad[1],
 511                 fh->fh_base.fh_pad[2],
 512                 fh->fh_base.fh_pad[3],
 513                 fh->fh_base.fh_pad[4],
 514                 fh->fh_base.fh_pad[5]);
 515         return buf;
 516 }
 517
 518 enum fsid_source fsid_source(struct svc_fh *fhp)
 519 {
 520         if (fhp->fh_handle.fh_version != 1)
 521                 return FSIDSOURCE_DEV;
 522         switch(fhp->fh_handle.fh_fsid_type) {
 523         case FSID_DEV:
 524         case FSID_ENCODE_DEV:
 525         case FSID_MAJOR_MINOR:
 526                 return FSIDSOURCE_DEV;
 527         case FSID_NUM:
 528                 return FSIDSOURCE_FSID;
 529         default:
 530                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 531                         return FSIDSOURCE_FSID;
 532                 else
 533                         return FSIDSOURCE_UUID;
 534         }
 535 }