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   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/svc.h>
  24 #include <linux/nfsd/nfsd.h>
  25
  26 #define NFSDDBG_FACILITY                NFSDDBG_FH
  27 #define NFSD_PARANOIA 1
  28 /* #define NFSD_DEBUG_VERBOSE 1 */
  29
  30
  31 static int nfsd_nr_verified;
  32 static int nfsd_nr_put;
  33
  34 extern struct export_operations export_op_default;
  35
  36 #define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
  37
  38 /*
  39  * our acceptability function.
  40  * if NOSUBTREECHECK, accept anything
  41  * if not, require that we can walk up to exp->ex_dentry
  42  * doing some checks on the 'x' bits
  43  */
  44 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  45 {
  46         struct svc_export *exp = expv;
  47         int rv;
  48         struct dentry *tdentry;
  49         struct dentry *parent;
  50
  51         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  52                 return 1;
  53
  54         tdentry = dget(dentry);
  55         while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
  56                 /* make sure parents give x permission to user */
  57                 int err;
  58                 parent = dget_parent(tdentry);
  59                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  60                 if (err < 0) {
  61                         dput(parent);
  62                         break;
  63                 }
  64                 dput(tdentry);
  65                 tdentry = parent;
  66         }
  67         if (tdentry != exp->ex_dentry)
  68                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  69         rv = (tdentry == exp->ex_dentry);
  70         dput(tdentry);
  71         return rv;
  72 }
  73
  74 /* Type check. The correct error return for type mismatches does not seem to be
  75  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  76  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  77  * the write call).
  78  */
  79 static inline __be32
  80 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  81 {
  82         /* Type can be negative when creating hardlinks - not to a dir */
  83         if (type > 0 && (mode & S_IFMT) != type) {
  84                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  85                         return nfserr_symlink;
  86                 else if (type == S_IFDIR)
  87                         return nfserr_notdir;
  88                 else if ((mode & S_IFMT) == S_IFDIR)
  89                         return nfserr_isdir;
  90                 else
  91                         return nfserr_inval;
  92         }
  93         if (type < 0 && (mode & S_IFMT) == -type) {
  94                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  95                         return nfserr_symlink;
  96                 else if (type == -S_IFDIR)
  97                         return nfserr_isdir;
  98                 else
  99                         return nfserr_notdir;
 100         }
 101         return 0;
 102 }
 103
 104 /*
 105  * Perform sanity checks on the dentry in a client's file handle.
 106  *
 107  * Note that the file handle dentry may need to be freed even after
 108  * an error return.
 109  *
 110  * This is only called at the start of an nfsproc call, so fhp points to
 111  * a svc_fh which is all 0 except for the over-the-wire file handle.
 112  */
 113 __be32
 114 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 115 {
 116         struct knfsd_fh *fh = &fhp->fh_handle;
 117         struct svc_export *exp = NULL;
 118         struct dentry   *dentry;
 119         __be32          error = 0;
 120
 121         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 122
 123         /* keep this filehandle for possible reference  when encoding attributes */
 124         rqstp->rq_reffh = fh;
 125
 126         if (!fhp->fh_dentry) {
 127                 __u32 *datap=NULL;
 128                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 129                 int fileid_type;
 130                 int data_left = fh->fh_size/4;
 131
 132                 error = nfserr_stale;
 133                 if (rqstp->rq_client == NULL)
 134                         goto out;
 135                 if (rqstp->rq_vers > 2)
 136                         error = nfserr_badhandle;
 137                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 138                         return nfserr_nofilehandle;
 139
 140                 if (fh->fh_version == 1) {
 141                         int len;
 142                         datap = fh->fh_auth;
 143                         if (--data_left<0) goto out;
 144                         switch (fh->fh_auth_type) {
 145                         case 0: break;
 146                         default: goto out;
 147                         }
 148                         len = key_len(fh->fh_fsid_type) / 4;
 149                         if (len == 0) goto out;
 150                         if  (fh->fh_fsid_type == 2) {
 151                                 /* deprecated, convert to type 3 */
 152                                 len = 3;
 153                                 fh->fh_fsid_type = 3;
 154                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 155                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 156                         }
 157                         if ((data_left -= len)<0) goto out;
 158                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
 159                         datap += len;
 160                 } else {
 161                         dev_t xdev;
 162                         ino_t xino;
 163                         if (fh->fh_size != NFS_FHSIZE)
 164                                 goto out;
 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_v0(tfh, xdev, xino);
 169                         exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle);
 170                 }
 171
 172                 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
 173                                 || PTR_ERR(exp) == -ETIMEDOUT)) {
 174                         error = nfserrno(PTR_ERR(exp));
 175                         goto out;
 176                 }
 177
 178                 error = nfserr_stale;
 179                 if (!exp || IS_ERR(exp))
 180                         goto out;
 181
 182                 /* Check if the request originated from a secure port. */
 183                 error = nfserr_perm;
 184                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 185                         printk(KERN_WARNING
 186                                "nfsd: request from insecure port (%u.%u.%u.%u:%d)!\n",
 187                                NIPQUAD(rqstp->rq_addr.sin_addr.s_addr),
 188                                ntohs(rqstp->rq_addr.sin_port));
 189                         goto out;
 190                 }
 191
 192                 /* Set user creds for this exportpoint */
 193                 error = nfserrno(nfsd_setuser(rqstp, exp));
 194                 if (error)
 195                         goto out;
 196
 197                 /*
 198                  * Look up the dentry using the NFS file handle.
 199                  */
 200                 error = nfserr_stale;
 201                 if (rqstp->rq_vers > 2)
 202                         error = nfserr_badhandle;
 203
 204                 if (fh->fh_version != 1) {
 205                         tfh[0] = fh->ofh_ino;
 206                         tfh[1] = fh->ofh_generation;
 207                         tfh[2] = fh->ofh_dirino;
 208                         datap = tfh;
 209                         data_left = 3;
 210                         if (fh->ofh_dirino == 0)
 211                                 fileid_type = 1;
 212                         else
 213                                 fileid_type = 2;
 214                 } else
 215                         fileid_type = fh->fh_fileid_type;
 216
 217                 if (fileid_type == 0)
 218                         dentry = dget(exp->ex_dentry);
 219                 else {
 220                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 221                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 222                                                      datap, data_left,
 223                                                      fileid_type,
 224                                                      nfsd_acceptable, exp);
 225                 }
 226                 if (dentry == NULL)
 227                         goto out;
 228                 if (IS_ERR(dentry)) {
 229                         if (PTR_ERR(dentry) != -EINVAL)
 230                                 error = nfserrno(PTR_ERR(dentry));
 231                         goto out;
 232                 }
 233 #ifdef NFSD_PARANOIA
 234                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 235                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 236                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 237                                dentry->d_parent->d_name.name, dentry->d_name.name);
 238                 }
 239 #endif
 240
 241                 fhp->fh_dentry = dentry;
 242                 fhp->fh_export = exp;
 243                 nfsd_nr_verified++;
 244         } else {
 245                 /* just rechecking permissions
 246                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 247                  */
 248                 dprintk("nfsd: fh_verify - just checking\n");
 249                 dentry = fhp->fh_dentry;
 250                 exp = fhp->fh_export;
 251                 /* Set user creds for this exportpoint; necessary even
 252                  * in the "just checking" case because this may be a
 253                  * filehandle that was created by fh_compose, and that
 254                  * is about to be used in another nfsv4 compound
 255                  * operation */
 256                 error = nfserrno(nfsd_setuser(rqstp, exp));
 257                 if (error)
 258                         goto out;
 259         }
 260         cache_get(&exp->h);
 261
 262
 263         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
 264         if (error)
 265                 goto out;
 266
 267         /* Finally, check access permissions. */
 268         error = nfsd_permission(exp, dentry, access);
 269
 270 #ifdef NFSD_PARANOIA_EXTREME
 271         if (error) {
 272                 printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n",
 273                        dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24));
 274         }
 275 #endif
 276 out:
 277         if (exp && !IS_ERR(exp))
 278                 exp_put(exp);
 279         if (error == nfserr_stale)
 280                 nfsdstats.fh_stale++;
 281         return error;
 282 }
 283
 284
 285 /*
 286  * Compose a file handle for an NFS reply.
 287  *
 288  * Note that when first composed, the dentry may not yet have
 289  * an inode.  In this case a call to fh_update should be made
 290  * before the fh goes out on the wire ...
 291  */
 292 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 293                              __u32 *datap, int *maxsize)
 294 {
 295         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 296
 297         if (dentry == exp->ex_dentry) {
 298                 *maxsize = 0;
 299                 return 0;
 300         }
 301
 302         return CALL(nop,encode_fh)(dentry, datap, maxsize,
 303                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
 304 }
 305
 306 /*
 307  * for composing old style file handles
 308  */
 309 static inline void _fh_update_old(struct dentry *dentry,
 310                                   struct svc_export *exp,
 311                                   struct knfsd_fh *fh)
 312 {
 313         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 314         fh->ofh_generation = dentry->d_inode->i_generation;
 315         if (S_ISDIR(dentry->d_inode->i_mode) ||
 316             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 317                 fh->ofh_dirino = 0;
 318 }
 319
 320 __be32
 321 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh)
 322 {
 323         /* ref_fh is a reference file handle.
 324          * if it is non-null and for the same filesystem, then we should compose
 325          * a filehandle which is of the same version, where possible.
 326          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 327          * Then create a 32byte filehandle using nfs_fhbase_old
 328          *
 329          */
 330
 331         u8 ref_fh_version = 0;
 332         u8 ref_fh_fsid_type = 0;
 333         struct inode * inode = dentry->d_inode;
 334         struct dentry *parent = dentry->d_parent;
 335         __u32 *datap;
 336         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 337
 338         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 339                 MAJOR(ex_dev), MINOR(ex_dev),
 340                 (long) exp->ex_dentry->d_inode->i_ino,
 341                 parent->d_name.name, dentry->d_name.name,
 342                 (inode ? inode->i_ino : 0));
 343
 344         if (ref_fh && ref_fh->fh_export == exp) {
 345                 ref_fh_version = ref_fh->fh_handle.fh_version;
 346                 if (ref_fh_version == 0xca)
 347                         ref_fh_fsid_type = 0;
 348                 else
 349                         ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
 350                 if (ref_fh_fsid_type > 3)
 351                         ref_fh_fsid_type = 0;
 352
 353                 /* make sure ref_fh type works for given export */
 354                 if (ref_fh_fsid_type == 1 &&
 355                     !(exp->ex_flags & NFSEXP_FSID)) {
 356                         /* if we don't have an fsid, we cannot provide one... */
 357                         ref_fh_fsid_type = 0;
 358                 }
 359         } else if (exp->ex_flags & NFSEXP_FSID)
 360                 ref_fh_fsid_type = 1;
 361
 362         if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
 363                 /* for newer device numbers, we must use a newer fsid format */
 364                 ref_fh_version = 1;
 365                 ref_fh_fsid_type = 3;
 366         }
 367         if (old_valid_dev(ex_dev) &&
 368             (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
 369                 /* must use type1 for smaller device numbers */
 370                 ref_fh_fsid_type = 0;
 371
 372         if (ref_fh == fhp)
 373                 fh_put(ref_fh);
 374
 375         if (fhp->fh_locked || fhp->fh_dentry) {
 376                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 377                         parent->d_name.name, dentry->d_name.name);
 378         }
 379         if (fhp->fh_maxsize < NFS_FHSIZE)
 380                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 381                        fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
 382
 383         fhp->fh_dentry = dget(dentry); /* our internal copy */
 384         fhp->fh_export = exp;
 385         cache_get(&exp->h);
 386
 387         if (ref_fh_version == 0xca) {
 388                 /* old style filehandle please */
 389                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 390                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 391                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 392                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 393                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 394                 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 395                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 396                 if (inode)
 397                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 398         } else {
 399                 int len;
 400                 fhp->fh_handle.fh_version = 1;
 401                 fhp->fh_handle.fh_auth_type = 0;
 402                 datap = fhp->fh_handle.fh_auth+0;
 403                 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
 404                 switch (ref_fh_fsid_type) {
 405                         case 0:
 406                                 /*
 407                                  * fsid_type 0:
 408                                  * 2byte major, 2byte minor, 4byte inode
 409                                  */
 410                                 mk_fsid_v0(datap, ex_dev,
 411                                         exp->ex_dentry->d_inode->i_ino);
 412                                 break;
 413                         case 1:
 414                                 /* fsid_type 1 == 4 bytes filesystem id */
 415                                 mk_fsid_v1(datap, exp->ex_fsid);
 416                                 break;
 417                         case 2:
 418                                 /*
 419                                  * fsid_type 2:
 420                                  * 4byte major, 4byte minor, 4byte inode
 421                                  */
 422                                 mk_fsid_v2(datap, ex_dev,
 423                                         exp->ex_dentry->d_inode->i_ino);
 424                                 break;
 425                         case 3:
 426                                 /*
 427                                  * fsid_type 3:
 428                                  * 4byte devicenumber, 4byte inode
 429                                  */
 430                                 mk_fsid_v3(datap, ex_dev,
 431                                         exp->ex_dentry->d_inode->i_ino);
 432                                 break;
 433                 }
 434                 len = key_len(ref_fh_fsid_type);
 435                 datap += len/4;
 436                 fhp->fh_handle.fh_size = 4 + len;
 437
 438                 if (inode) {
 439                         int size = (fhp->fh_maxsize-len-4)/4;
 440                         fhp->fh_handle.fh_fileid_type =
 441                                 _fh_update(dentry, exp, datap, &size);
 442                         fhp->fh_handle.fh_size += size*4;
 443                 }
 444                 if (fhp->fh_handle.fh_fileid_type == 255)
 445                         return nfserr_opnotsupp;
 446         }
 447
 448         nfsd_nr_verified++;
 449         return 0;
 450 }
 451
 452 /*
 453  * Update file handle information after changing a dentry.
 454  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 455  */
 456 __be32
 457 fh_update(struct svc_fh *fhp)
 458 {
 459         struct dentry *dentry;
 460         __u32 *datap;
 461
 462         if (!fhp->fh_dentry)
 463                 goto out_bad;
 464
 465         dentry = fhp->fh_dentry;
 466         if (!dentry->d_inode)
 467                 goto out_negative;
 468         if (fhp->fh_handle.fh_version != 1) {
 469                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 470         } else {
 471                 int size;
 472                 if (fhp->fh_handle.fh_fileid_type != 0)
 473                         goto out;
 474                 datap = fhp->fh_handle.fh_auth+
 475                         fhp->fh_handle.fh_size/4 -1;
 476                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 477                 fhp->fh_handle.fh_fileid_type =
 478                         _fh_update(dentry, fhp->fh_export, datap, &size);
 479                 fhp->fh_handle.fh_size += size*4;
 480                 if (fhp->fh_handle.fh_fileid_type == 255)
 481                         return nfserr_opnotsupp;
 482         }
 483 out:
 484         return 0;
 485
 486 out_bad:
 487         printk(KERN_ERR "fh_update: fh not verified!\n");
 488         goto out;
 489 out_negative:
 490         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 491                 dentry->d_parent->d_name.name, dentry->d_name.name);
 492         goto out;
 493 }
 494
 495 /*
 496  * Release a file handle.
 497  */
 498 void
 499 fh_put(struct svc_fh *fhp)
 500 {
 501         struct dentry * dentry = fhp->fh_dentry;
 502         struct svc_export * exp = fhp->fh_export;
 503         if (dentry) {
 504                 fh_unlock(fhp);
 505                 fhp->fh_dentry = NULL;
 506                 dput(dentry);
 507 #ifdef CONFIG_NFSD_V3
 508                 fhp->fh_pre_saved = 0;
 509                 fhp->fh_post_saved = 0;
 510 #endif
 511                 nfsd_nr_put++;
 512         }
 513         if (exp) {
 514                 cache_put(&exp->h, &svc_export_cache);
 515                 fhp->fh_export = NULL;
 516         }
 517         return;
 518 }
 519
 520 /*
 521  * Shorthand for dprintk()'s
 522  */
 523 char * SVCFH_fmt(struct svc_fh *fhp)
 524 {
 525         struct knfsd_fh *fh = &fhp->fh_handle;
 526
 527         static char buf[80];
 528         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 529                 fh->fh_size,
 530                 fh->fh_base.fh_pad[0],
 531                 fh->fh_base.fh_pad[1],
 532                 fh->fh_base.fh_pad[2],
 533                 fh->fh_base.fh_pad[3],
 534                 fh->fh_base.fh_pad[4],
 535                 fh->fh_base.fh_pad[5]);
 536         return buf;
 537 }