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         /* keep this filehandle for possible reference  when encoding attributes */
 123         rqstp->rq_reffh = fh;
 124
 125         if (!fhp->fh_dentry) {
 126                 __u32 *datap=NULL;
 127                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 128                 int fileid_type;
 129                 int data_left = fh->fh_size/4;
 130
 131                 error = nfserr_stale;
 132                 if (rqstp->rq_client == NULL)
 133                         goto out;
 134                 if (rqstp->rq_vers > 2)
 135                         error = nfserr_badhandle;
 136                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 137                         return nfserr_nofilehandle;
 138
 139                 if (fh->fh_version == 1) {
 140                         int len;
 141                         datap = fh->fh_auth;
 142                         if (--data_left<0) goto out;
 143                         switch (fh->fh_auth_type) {
 144                         case 0: break;
 145                         default: goto out;
 146                         }
 147                         len = key_len(fh->fh_fsid_type) / 4;
 148                         if (len == 0) goto out;
 149                         if  (fh->fh_fsid_type == 2) {
 150                                 /* deprecated, convert to type 3 */
 151                                 len = 3;
 152                                 fh->fh_fsid_type = 3;
 153                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 154                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 155                         }
 156                         if ((data_left -= len)<0) goto out;
 157                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
 158                         datap += len;
 159                 } else {
 160                         dev_t xdev;
 161                         ino_t xino;
 162                         if (fh->fh_size != NFS_FHSIZE)
 163                                 goto out;
 164                         /* assume old filehandle format */
 165                         xdev = old_decode_dev(fh->ofh_xdev);
 166                         xino = u32_to_ino_t(fh->ofh_xino);
 167                         mk_fsid_v0(tfh, xdev, xino);
 168                         exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle);
 169                 }
 170
 171                 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
 172                                 || PTR_ERR(exp) == -ETIMEDOUT)) {
 173                         error = nfserrno(PTR_ERR(exp));
 174                         goto out;
 175                 }
 176
 177                 error = nfserr_stale;
 178                 if (!exp || IS_ERR(exp))
 179                         goto out;
 180
 181                 /* Check if the request originated from a secure port. */
 182                 error = nfserr_perm;
 183                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 184                         char buf[RPC_MAX_ADDRBUFLEN];
 185                         printk(KERN_WARNING
 186                                "nfsd: request from insecure port %s!\n",
 187                                svc_print_addr(rqstp, buf, sizeof(buf)));
 188                         goto out;
 189                 }
 190
 191                 /* Set user creds for this exportpoint */
 192                 error = nfserrno(nfsd_setuser(rqstp, exp));
 193                 if (error)
 194                         goto out;
 195
 196                 /*
 197                  * Look up the dentry using the NFS file handle.
 198                  */
 199                 error = nfserr_stale;
 200                 if (rqstp->rq_vers > 2)
 201                         error = nfserr_badhandle;
 202
 203                 if (fh->fh_version != 1) {
 204                         tfh[0] = fh->ofh_ino;
 205                         tfh[1] = fh->ofh_generation;
 206                         tfh[2] = fh->ofh_dirino;
 207                         datap = tfh;
 208                         data_left = 3;
 209                         if (fh->ofh_dirino == 0)
 210                                 fileid_type = 1;
 211                         else
 212                                 fileid_type = 2;
 213                 } else
 214                         fileid_type = fh->fh_fileid_type;
 215
 216                 if (fileid_type == 0)
 217                         dentry = dget(exp->ex_dentry);
 218                 else {
 219                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 220                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 221                                                      datap, data_left,
 222                                                      fileid_type,
 223                                                      nfsd_acceptable, exp);
 224                 }
 225                 if (dentry == NULL)
 226                         goto out;
 227                 if (IS_ERR(dentry)) {
 228                         if (PTR_ERR(dentry) != -EINVAL)
 229                                 error = nfserrno(PTR_ERR(dentry));
 230                         goto out;
 231                 }
 232
 233                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 234                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 235                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 236                                dentry->d_parent->d_name.name, dentry->d_name.name);
 237                 }
 238
 239                 fhp->fh_dentry = dentry;
 240                 fhp->fh_export = exp;
 241                 nfsd_nr_verified++;
 242         } else {
 243                 /* just rechecking permissions
 244                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 245                  */
 246                 dprintk("nfsd: fh_verify - just checking\n");
 247                 dentry = fhp->fh_dentry;
 248                 exp = fhp->fh_export;
 249                 /* Set user creds for this exportpoint; necessary even
 250                  * in the "just checking" case because this may be a
 251                  * filehandle that was created by fh_compose, and that
 252                  * is about to be used in another nfsv4 compound
 253                  * operation */
 254                 error = nfserrno(nfsd_setuser(rqstp, exp));
 255                 if (error)
 256                         goto out;
 257         }
 258         cache_get(&exp->h);
 259
 260
 261         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 262         if (error)
 263                 goto out;
 264
 265         /* Finally, check access permissions. */
 266         error = nfsd_permission(exp, dentry, access);
 267
 268         if (error) {
 269                 dprintk("fh_verify: %s/%s permission failure, "
 270                         "acc=%x, error=%d\n",
 271                         dentry->d_parent->d_name.name,
 272                         dentry->d_name.name,
 273                         access, ntohl(error));
 274         }
 275 out:
 276         if (exp && !IS_ERR(exp))
 277                 exp_put(exp);
 278         if (error == nfserr_stale)
 279                 nfsdstats.fh_stale++;
 280         return error;
 281 }
 282
 283
 284 /*
 285  * Compose a file handle for an NFS reply.
 286  *
 287  * Note that when first composed, the dentry may not yet have
 288  * an inode.  In this case a call to fh_update should be made
 289  * before the fh goes out on the wire ...
 290  */
 291 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 292                              __u32 *datap, int *maxsize)
 293 {
 294         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 295
 296         if (dentry == exp->ex_dentry) {
 297                 *maxsize = 0;
 298                 return 0;
 299         }
 300
 301         return CALL(nop,encode_fh)(dentry, datap, maxsize,
 302                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
 303 }
 304
 305 /*
 306  * for composing old style file handles
 307  */
 308 static inline void _fh_update_old(struct dentry *dentry,
 309                                   struct svc_export *exp,
 310                                   struct knfsd_fh *fh)
 311 {
 312         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 313         fh->ofh_generation = dentry->d_inode->i_generation;
 314         if (S_ISDIR(dentry->d_inode->i_mode) ||
 315             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 316                 fh->ofh_dirino = 0;
 317 }
 318
 319 __be32
 320 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh)
 321 {
 322         /* ref_fh is a reference file handle.
 323          * if it is non-null and for the same filesystem, then we should compose
 324          * a filehandle which is of the same version, where possible.
 325          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 326          * Then create a 32byte filehandle using nfs_fhbase_old
 327          *
 328          */
 329
 330         u8 ref_fh_version = 0;
 331         u8 ref_fh_fsid_type = 0;
 332         struct inode * inode = dentry->d_inode;
 333         struct dentry *parent = dentry->d_parent;
 334         __u32 *datap;
 335         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 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         if (ref_fh && ref_fh->fh_export == exp) {
 344                 ref_fh_version = ref_fh->fh_handle.fh_version;
 345                 if (ref_fh_version == 0xca)
 346                         ref_fh_fsid_type = 0;
 347                 else
 348                         ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
 349                 if (ref_fh_fsid_type > 3)
 350                         ref_fh_fsid_type = 0;
 351
 352                 /* make sure ref_fh type works for given export */
 353                 if (ref_fh_fsid_type == 1 &&
 354                     !(exp->ex_flags & NFSEXP_FSID)) {
 355                         /* if we don't have an fsid, we cannot provide one... */
 356                         ref_fh_fsid_type = 0;
 357                 }
 358         } else if (exp->ex_flags & NFSEXP_FSID)
 359                 ref_fh_fsid_type = 1;
 360
 361         if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
 362                 /* for newer device numbers, we must use a newer fsid format */
 363                 ref_fh_version = 1;
 364                 ref_fh_fsid_type = 3;
 365         }
 366         if (old_valid_dev(ex_dev) &&
 367             (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
 368                 /* must use type1 for smaller device numbers */
 369                 ref_fh_fsid_type = 0;
 370
 371         if (ref_fh == fhp)
 372                 fh_put(ref_fh);
 373
 374         if (fhp->fh_locked || fhp->fh_dentry) {
 375                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 376                         parent->d_name.name, dentry->d_name.name);
 377         }
 378         if (fhp->fh_maxsize < NFS_FHSIZE)
 379                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 380                        fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
 381
 382         fhp->fh_dentry = dget(dentry); /* our internal copy */
 383         fhp->fh_export = exp;
 384         cache_get(&exp->h);
 385
 386         if (ref_fh_version == 0xca) {
 387                 /* old style filehandle please */
 388                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 389                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 390                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 391                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 392                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 393                 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 394                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 395                 if (inode)
 396                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 397         } else {
 398                 int len;
 399                 fhp->fh_handle.fh_version = 1;
 400                 fhp->fh_handle.fh_auth_type = 0;
 401                 datap = fhp->fh_handle.fh_auth+0;
 402                 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
 403                 switch (ref_fh_fsid_type) {
 404                         case 0:
 405                                 /*
 406                                  * fsid_type 0:
 407                                  * 2byte major, 2byte minor, 4byte inode
 408                                  */
 409                                 mk_fsid_v0(datap, ex_dev,
 410                                         exp->ex_dentry->d_inode->i_ino);
 411                                 break;
 412                         case 1:
 413                                 /* fsid_type 1 == 4 bytes filesystem id */
 414                                 mk_fsid_v1(datap, exp->ex_fsid);
 415                                 break;
 416                         case 2:
 417                                 /*
 418                                  * fsid_type 2:
 419                                  * 4byte major, 4byte minor, 4byte inode
 420                                  */
 421                                 mk_fsid_v2(datap, ex_dev,
 422                                         exp->ex_dentry->d_inode->i_ino);
 423                                 break;
 424                         case 3:
 425                                 /*
 426                                  * fsid_type 3:
 427                                  * 4byte devicenumber, 4byte inode
 428                                  */
 429                                 mk_fsid_v3(datap, ex_dev,
 430                                         exp->ex_dentry->d_inode->i_ino);
 431                                 break;
 432                 }
 433                 len = key_len(ref_fh_fsid_type);
 434                 datap += len/4;
 435                 fhp->fh_handle.fh_size = 4 + len;
 436
 437                 if (inode) {
 438                         int size = (fhp->fh_maxsize-len-4)/4;
 439                         fhp->fh_handle.fh_fileid_type =
 440                                 _fh_update(dentry, exp, datap, &size);
 441                         fhp->fh_handle.fh_size += size*4;
 442                 }
 443                 if (fhp->fh_handle.fh_fileid_type == 255)
 444                         return nfserr_opnotsupp;
 445         }
 446
 447         nfsd_nr_verified++;
 448         return 0;
 449 }
 450
 451 /*
 452  * Update file handle information after changing a dentry.
 453  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 454  */
 455 __be32
 456 fh_update(struct svc_fh *fhp)
 457 {
 458         struct dentry *dentry;
 459         __u32 *datap;
 460
 461         if (!fhp->fh_dentry)
 462                 goto out_bad;
 463
 464         dentry = fhp->fh_dentry;
 465         if (!dentry->d_inode)
 466                 goto out_negative;
 467         if (fhp->fh_handle.fh_version != 1) {
 468                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 469         } else {
 470                 int size;
 471                 if (fhp->fh_handle.fh_fileid_type != 0)
 472                         goto out;
 473                 datap = fhp->fh_handle.fh_auth+
 474                         fhp->fh_handle.fh_size/4 -1;
 475                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 476                 fhp->fh_handle.fh_fileid_type =
 477                         _fh_update(dentry, fhp->fh_export, datap, &size);
 478                 fhp->fh_handle.fh_size += size*4;
 479                 if (fhp->fh_handle.fh_fileid_type == 255)
 480                         return nfserr_opnotsupp;
 481         }
 482 out:
 483         return 0;
 484
 485 out_bad:
 486         printk(KERN_ERR "fh_update: fh not verified!\n");
 487         goto out;
 488 out_negative:
 489         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 490                 dentry->d_parent->d_name.name, dentry->d_name.name);
 491         goto out;
 492 }
 493
 494 /*
 495  * Release a file handle.
 496  */
 497 void
 498 fh_put(struct svc_fh *fhp)
 499 {
 500         struct dentry * dentry = fhp->fh_dentry;
 501         struct svc_export * exp = fhp->fh_export;
 502         if (dentry) {
 503                 fh_unlock(fhp);
 504                 fhp->fh_dentry = NULL;
 505                 dput(dentry);
 506 #ifdef CONFIG_NFSD_V3
 507                 fhp->fh_pre_saved = 0;
 508                 fhp->fh_post_saved = 0;
 509 #endif
 510                 nfsd_nr_put++;
 511         }
 512         if (exp) {
 513                 cache_put(&exp->h, &svc_export_cache);
 514                 fhp->fh_export = NULL;
 515         }
 516         return;
 517 }
 518
 519 /*
 520  * Shorthand for dprintk()'s
 521  */
 522 char * SVCFH_fmt(struct svc_fh *fhp)
 523 {
 524         struct knfsd_fh *fh = &fhp->fh_handle;
 525
 526         static char buf[80];
 527         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 528                 fh->fh_size,
 529                 fh->fh_base.fh_pad[0],
 530                 fh->fh_base.fh_pad[1],
 531                 fh->fh_base.fh_pad[2],
 532                 fh->fh_base.fh_pad[3],
 533                 fh->fh_base.fh_pad[4],
 534                 fh->fh_base.fh_pad[5]);
 535         return buf;
 536 }