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/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 int
  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 u32
 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         u32             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                 error = nfserr_dropit;
 173                 if (IS_ERR(exp) && PTR_ERR(exp) == -EAGAIN)
 174                         goto out;
 175
 176                 error = nfserr_stale;
 177                 if (!exp || IS_ERR(exp))
 178                         goto out;
 179
 180                 /* Check if the request originated from a secure port. */
 181                 error = nfserr_perm;
 182                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 183                         printk(KERN_WARNING
 184                                "nfsd: request from insecure port (%u.%u.%u.%u:%d)!\n",
 185                                NIPQUAD(rqstp->rq_addr.sin_addr.s_addr),
 186                                ntohs(rqstp->rq_addr.sin_port));
 187                         goto out;
 188                 }
 189
 190                 /* Set user creds for this exportpoint */
 191                 error = nfserrno(nfsd_setuser(rqstp, exp));
 192                 if (error)
 193                         goto out;
 194
 195                 /*
 196                  * Look up the dentry using the NFS file handle.
 197                  */
 198                 error = nfserr_stale;
 199                 if (rqstp->rq_vers > 2)
 200                         error = nfserr_badhandle;
 201
 202                 if (fh->fh_version != 1) {
 203                         tfh[0] = fh->ofh_ino;
 204                         tfh[1] = fh->ofh_generation;
 205                         tfh[2] = fh->ofh_dirino;
 206                         datap = tfh;
 207                         data_left = 3;
 208                         if (fh->ofh_dirino == 0)
 209                                 fileid_type = 1;
 210                         else
 211                                 fileid_type = 2;
 212                 } else
 213                         fileid_type = fh->fh_fileid_type;
 214
 215                 if (fileid_type == 0)
 216                         dentry = dget(exp->ex_dentry);
 217                 else {
 218                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 219                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 220                                                      datap, data_left,
 221                                                      fileid_type,
 222                                                      nfsd_acceptable, exp);
 223                 }
 224                 if (dentry == NULL)
 225                         goto out;
 226                 if (IS_ERR(dentry)) {
 227                         if (PTR_ERR(dentry) != -EINVAL)
 228                                 error = nfserrno(PTR_ERR(dentry));
 229                         goto out;
 230                 }
 231 #ifdef NFSD_PARANOIA
 232                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 233                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 234                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 235                                dentry->d_parent->d_name.name, dentry->d_name.name);
 236                 }
 237 #endif
 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 #ifdef NFSD_PARANOIA_EXTREME
 269         if (error) {
 270                 printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n",
 271                        dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24));
 272         }
 273 #endif
 274 out:
 275         if (exp && !IS_ERR(exp))
 276                 exp_put(exp);
 277         if (error == nfserr_stale)
 278                 nfsdstats.fh_stale++;
 279         return error;
 280 }
 281
 282
 283 /*
 284  * Compose a file handle for an NFS reply.
 285  *
 286  * Note that when first composed, the dentry may not yet have
 287  * an inode.  In this case a call to fh_update should be made
 288  * before the fh goes out on the wire ...
 289  */
 290 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 291                              __u32 *datap, int *maxsize)
 292 {
 293         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 294
 295         if (dentry == exp->ex_dentry) {
 296                 *maxsize = 0;
 297                 return 0;
 298         }
 299
 300         return CALL(nop,encode_fh)(dentry, datap, maxsize,
 301                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
 302 }
 303
 304 /*
 305  * for composing old style file handles
 306  */
 307 static inline void _fh_update_old(struct dentry *dentry,
 308                                   struct svc_export *exp,
 309                                   struct knfsd_fh *fh)
 310 {
 311         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 312         fh->ofh_generation = dentry->d_inode->i_generation;
 313         if (S_ISDIR(dentry->d_inode->i_mode) ||
 314             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 315                 fh->ofh_dirino = 0;
 316 }
 317
 318 int
 319 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, 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 ref_fh_version = 0;
 330         u8 ref_fh_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
 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         if (ref_fh && ref_fh->fh_export == exp) {
 343                 ref_fh_version = ref_fh->fh_handle.fh_version;
 344                 if (ref_fh_version == 0xca)
 345                         ref_fh_fsid_type = 0;
 346                 else
 347                         ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
 348                 if (ref_fh_fsid_type > 3)
 349                         ref_fh_fsid_type = 0;
 350
 351                 /* make sure ref_fh type works for given export */
 352                 if (ref_fh_fsid_type == 1 &&
 353                     !(exp->ex_flags & NFSEXP_FSID)) {
 354                         /* if we don't have an fsid, we cannot provide one... */
 355                         ref_fh_fsid_type = 0;
 356                 }
 357         } else if (exp->ex_flags & NFSEXP_FSID)
 358                 ref_fh_fsid_type = 1;
 359
 360         if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
 361                 /* for newer device numbers, we must use a newer fsid format */
 362                 ref_fh_version = 1;
 363                 ref_fh_fsid_type = 3;
 364         }
 365         if (old_valid_dev(ex_dev) &&
 366             (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
 367                 /* must use type1 for smaller device numbers */
 368                 ref_fh_fsid_type = 0;
 369
 370         if (ref_fh == fhp)
 371                 fh_put(ref_fh);
 372
 373         if (fhp->fh_locked || fhp->fh_dentry) {
 374                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 375                         parent->d_name.name, dentry->d_name.name);
 376         }
 377         if (fhp->fh_maxsize < NFS_FHSIZE)
 378                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 379                        fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
 380
 381         fhp->fh_dentry = dget(dentry); /* our internal copy */
 382         fhp->fh_export = exp;
 383         cache_get(&exp->h);
 384
 385         if (ref_fh_version == 0xca) {
 386                 /* old style filehandle please */
 387                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 388                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 389                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 390                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 391                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 392                 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 393                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 394                 if (inode)
 395                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 396         } else {
 397                 int len;
 398                 fhp->fh_handle.fh_version = 1;
 399                 fhp->fh_handle.fh_auth_type = 0;
 400                 datap = fhp->fh_handle.fh_auth+0;
 401                 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
 402                 switch (ref_fh_fsid_type) {
 403                         case 0:
 404                                 /*
 405                                  * fsid_type 0:
 406                                  * 2byte major, 2byte minor, 4byte inode
 407                                  */
 408                                 mk_fsid_v0(datap, ex_dev,
 409                                         exp->ex_dentry->d_inode->i_ino);
 410                                 break;
 411                         case 1:
 412                                 /* fsid_type 1 == 4 bytes filesystem id */
 413                                 mk_fsid_v1(datap, exp->ex_fsid);
 414                                 break;
 415                         case 2:
 416                                 /*
 417                                  * fsid_type 2:
 418                                  * 4byte major, 4byte minor, 4byte inode
 419                                  */
 420                                 mk_fsid_v2(datap, ex_dev,
 421                                         exp->ex_dentry->d_inode->i_ino);
 422                                 break;
 423                         case 3:
 424                                 /*
 425                                  * fsid_type 3:
 426                                  * 4byte devicenumber, 4byte inode
 427                                  */
 428                                 mk_fsid_v3(datap, ex_dev,
 429                                         exp->ex_dentry->d_inode->i_ino);
 430                                 break;
 431                 }
 432                 len = key_len(ref_fh_fsid_type);
 433                 datap += len/4;
 434                 fhp->fh_handle.fh_size = 4 + len;
 435
 436                 if (inode) {
 437                         int size = (fhp->fh_maxsize-len-4)/4;
 438                         fhp->fh_handle.fh_fileid_type =
 439                                 _fh_update(dentry, exp, datap, &size);
 440                         fhp->fh_handle.fh_size += size*4;
 441                 }
 442                 if (fhp->fh_handle.fh_fileid_type == 255)
 443                         return nfserr_opnotsupp;
 444         }
 445
 446         nfsd_nr_verified++;
 447         return 0;
 448 }
 449
 450 /*
 451  * Update file handle information after changing a dentry.
 452  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 453  */
 454 int
 455 fh_update(struct svc_fh *fhp)
 456 {
 457         struct dentry *dentry;
 458         __u32 *datap;
 459
 460         if (!fhp->fh_dentry)
 461                 goto out_bad;
 462
 463         dentry = fhp->fh_dentry;
 464         if (!dentry->d_inode)
 465                 goto out_negative;
 466         if (fhp->fh_handle.fh_version != 1) {
 467                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 468         } else {
 469                 int size;
 470                 if (fhp->fh_handle.fh_fileid_type != 0)
 471                         goto out;
 472                 datap = fhp->fh_handle.fh_auth+
 473                         fhp->fh_handle.fh_size/4 -1;
 474                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 475                 fhp->fh_handle.fh_fileid_type =
 476                         _fh_update(dentry, fhp->fh_export, datap, &size);
 477                 fhp->fh_handle.fh_size += size*4;
 478                 if (fhp->fh_handle.fh_fileid_type == 255)
 479                         return nfserr_opnotsupp;
 480         }
 481 out:
 482         return 0;
 483
 484 out_bad:
 485         printk(KERN_ERR "fh_update: fh not verified!\n");
 486         goto out;
 487 out_negative:
 488         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 489                 dentry->d_parent->d_name.name, dentry->d_name.name);
 490         goto out;
 491 }
 492
 493 /*
 494  * Release a file handle.
 495  */
 496 void
 497 fh_put(struct svc_fh *fhp)
 498 {
 499         struct dentry * dentry = fhp->fh_dentry;
 500         struct svc_export * exp = fhp->fh_export;
 501         if (dentry) {
 502                 fh_unlock(fhp);
 503                 fhp->fh_dentry = NULL;
 504                 dput(dentry);
 505 #ifdef CONFIG_NFSD_V3
 506                 fhp->fh_pre_saved = 0;
 507                 fhp->fh_post_saved = 0;
 508 #endif
 509                 nfsd_nr_put++;
 510         }
 511         if (exp) {
 512                 cache_put(&exp->h, &svc_export_cache);
 513                 fhp->fh_export = NULL;
 514         }
 515         return;
 516 }
 517
 518 /*
 519  * Shorthand for dprintk()'s
 520  */
 521 char * SVCFH_fmt(struct svc_fh *fhp)
 522 {
 523         struct knfsd_fh *fh = &fhp->fh_handle;
 524
 525         static char buf[80];
 526         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 527                 fh->fh_size,
 528                 fh->fh_base.fh_pad[0],
 529                 fh->fh_base.fh_pad[1],
 530                 fh->fh_base.fh_pad[2],
 531                 fh->fh_base.fh_pad[3],
 532                 fh->fh_base.fh_pad[4],
 533                 fh->fh_base.fh_pad[5]);
 534         return buf;
 535 }