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 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
  75 /*
  76  * Perform sanity checks on the dentry in a client's file handle.
  77  *
  78  * Note that the file handle dentry may need to be freed even after
  79  * an error return.
  80  *
  81  * This is only called at the start of an nfsproc call, so fhp points to
  82  * a svc_fh which is all 0 except for the over-the-wire file handle.
  83  */
  84 u32
  85 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
  86 {
  87         struct knfsd_fh *fh = &fhp->fh_handle;
  88         struct svc_export *exp = NULL;
  89         struct dentry   *dentry;
  90         struct inode    *inode;
  91         u32             error = 0;
  92
  93         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
  94
  95         /* keep this filehandle for possible reference  when encoding attributes */
  96         rqstp->rq_reffh = fh;
  97
  98         if (!fhp->fh_dentry) {
  99                 __u32 *datap=NULL;
 100                 __u32 tfh[3];           /* filehandle fragment for oldstyle filehandles */
 101                 int fileid_type;
 102                 int data_left = fh->fh_size/4;
 103
 104                 error = nfserr_stale;
 105                 if (rqstp->rq_client == NULL)
 106                         goto out;
 107                 if (rqstp->rq_vers > 2)
 108                         error = nfserr_badhandle;
 109                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 110                         return nfserr_nofilehandle;
 111
 112                 if (fh->fh_version == 1) {
 113                         int len;
 114                         datap = fh->fh_auth;
 115                         if (--data_left<0) goto out;
 116                         switch (fh->fh_auth_type) {
 117                         case 0: break;
 118                         default: goto out;
 119                         }
 120                         len = key_len(fh->fh_fsid_type) / 4;
 121                         if (len == 0) goto out;
 122                         if  (fh->fh_fsid_type == 2) {
 123                                 /* deprecated, convert to type 3 */
 124                                 len = 3;
 125                                 fh->fh_fsid_type = 3;
 126                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 127                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 128                         }
 129                         if ((data_left -= len)<0) goto out;
 130                         exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
 131                         datap += len;
 132                 } else {
 133                         dev_t xdev;
 134                         ino_t xino;
 135                         if (fh->fh_size != NFS_FHSIZE)
 136                                 goto out;
 137                         /* assume old filehandle format */
 138                         xdev = old_decode_dev(fh->ofh_xdev);
 139                         xino = u32_to_ino_t(fh->ofh_xino);
 140                         mk_fsid_v0(tfh, xdev, xino);
 141                         exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle);
 142                 }
 143
 144                 error = nfserr_dropit;
 145                 if (IS_ERR(exp) && PTR_ERR(exp) == -EAGAIN) {
 146                         dprintk("nfsd: fh_verify failed: nfserr_dropit\n");
 147                         goto out;
 148                 }
 149                 error = nfserr_stale;
 150                 if (!exp || IS_ERR(exp)) {
 151                         dprintk("nfsd: fh_verify failed: nfserr_stale\n");
 152                         goto out;
 153                 }
 154                 /* Check if the request originated from a secure port. */
 155                 error = nfserr_perm;
 156                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 157                         printk(KERN_WARNING
 158                                "nfsd: request from insecure port (%u.%u.%u.%u:%d)!\n",
 159                                NIPQUAD(rqstp->rq_addr.sin_addr.s_addr),
 160                                ntohs(rqstp->rq_addr.sin_port));
 161                         goto out;
 162                 }
 163
 164                 /* Set user creds for this exportpoint */
 165                 error = nfsd_setuser(rqstp, exp);
 166                 if (error) {
 167                         dprintk("nfsd: nfsd_setuser failed: %d\n", error);
 168                         error = nfserrno(error);
 169                         goto out;
 170                 }
 171
 172                 /*
 173                  * Look up the dentry using the NFS file handle.
 174                  */
 175                 error = nfserr_stale;
 176                 if (rqstp->rq_vers > 2)
 177                         error = nfserr_badhandle;
 178
 179                 if (fh->fh_version != 1) {
 180                         tfh[0] = fh->ofh_ino;
 181                         tfh[1] = fh->ofh_generation;
 182                         tfh[2] = fh->ofh_dirino;
 183                         datap = tfh;
 184                         data_left = 3;
 185                         if (fh->ofh_dirino == 0)
 186                                 fileid_type = 1;
 187                         else
 188                                 fileid_type = 2;
 189                 } else
 190                         fileid_type = fh->fh_fileid_type;
 191
 192                 if (fileid_type == 0)
 193                         dentry = dget(exp->ex_dentry);
 194                 else {
 195                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 196                         dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 197                                                      datap, data_left,
 198                                                      fileid_type,
 199                                                      nfsd_acceptable, exp);
 200                 }
 201                 if (dentry == NULL)
 202                         goto out;
 203                 if (IS_ERR(dentry)) {
 204                         dprintk("nfsd: CALL(nop,decode_fh) failed: %ld\n", PTR_ERR(dentry));
 205                         if (PTR_ERR(dentry) != -EINVAL)
 206                                 error = nfserrno(PTR_ERR(dentry));
 207                         goto out;
 208                 }
 209 #ifdef NFSD_PARANOIA
 210                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 211                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 212                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 213                                dentry->d_parent->d_name.name, dentry->d_name.name);
 214                 }
 215 #endif
 216
 217                 fhp->fh_dentry = dentry;
 218                 fhp->fh_export = exp;
 219                 nfsd_nr_verified++;
 220         } else {
 221                 /* just rechecking permissions
 222                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 223                  */
 224                 dprintk("nfsd: fh_verify - just checking\n");
 225                 dentry = fhp->fh_dentry;
 226                 exp = fhp->fh_export;
 227         }
 228         cache_get(&exp->h);
 229
 230         inode = dentry->d_inode;
 231
 232
 233         /* Type check. The correct error return for type mismatches
 234          * does not seem to be generally agreed upon. SunOS seems to
 235          * use EISDIR if file isn't S_IFREG; a comment in the NFSv3
 236          * spec says this is incorrect (implementation notes for the
 237          * write call).
 238          */
 239
 240         /* Type can be negative when creating hardlinks - not to a dir */
 241         if (type > 0 && (inode->i_mode & S_IFMT) != type) {
 242                 if (rqstp->rq_vers == 4 && (inode->i_mode & S_IFMT) == S_IFLNK)
 243                         error = nfserr_symlink;
 244                 else if (type == S_IFDIR)
 245                         error = nfserr_notdir;
 246                 else if ((inode->i_mode & S_IFMT) == S_IFDIR)
 247                         error = nfserr_isdir;
 248                 else
 249                         error = nfserr_inval;
 250                 dprintk("nfsd: bad type: %d\n", ntohl(error));
 251                 goto out;
 252         }
 253         if (type < 0 && (inode->i_mode & S_IFMT) == -type) {
 254                 if (rqstp->rq_vers == 4 && (inode->i_mode & S_IFMT) == S_IFLNK)
 255                         error = nfserr_symlink;
 256                 else if (type == -S_IFDIR)
 257                         error = nfserr_isdir;
 258                 else
 259                         error = nfserr_notdir;
 260                 dprintk("nfsd: bad type2: %d\n", ntohl(error));
 261                 goto out;
 262         }
 263
 264         /* Finally, check access permissions. */
 265         error = nfsd_permission(exp, dentry, access);
 266
 267 #ifdef NFSD_PARANOIA_EXTREME
 268         if (error) {
 269                 printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n",
 270                        dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24));
 271         }
 272 #endif
 273 out:
 274         if (exp && !IS_ERR(exp))
 275                 exp_put(exp);
 276         if (error == nfserr_stale)
 277                 nfsdstats.fh_stale++;
 278         return error;
 279 }
 280
 281
 282 /*
 283  * Compose a file handle for an NFS reply.
 284  *
 285  * Note that when first composed, the dentry may not yet have
 286  * an inode.  In this case a call to fh_update should be made
 287  * before the fh goes out on the wire ...
 288  */
 289 inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 290                       __u32 *datap, int *maxsize)
 291 {
 292         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 293
 294         if (dentry == exp->ex_dentry) {
 295                 *maxsize = 0;
 296                 return 0;
 297         }
 298
 299         return CALL(nop,encode_fh)(dentry, datap, maxsize,
 300                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
 301 }
 302
 303 /*
 304  * for composing old style file handles
 305  */
 306 inline void _fh_update_old(struct dentry *dentry, 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 int
 317 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh)
 318 {
 319         /* ref_fh is a reference file handle.
 320          * if it is non-null, then we should compose a filehandle which is
 321          * 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 ref_fh_version = 0;
 328         u8 ref_fh_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
 334         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 335                 MAJOR(ex_dev), MINOR(ex_dev),
 336                 (long) exp->ex_dentry->d_inode->i_ino,
 337                 parent->d_name.name, dentry->d_name.name,
 338                 (inode ? inode->i_ino : 0));
 339
 340         if (ref_fh) {
 341                 ref_fh_version = ref_fh->fh_handle.fh_version;
 342                 if (ref_fh_version == 0xca)
 343                         ref_fh_fsid_type = 0;
 344                 else
 345                         ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
 346                 if (ref_fh_fsid_type > 3)
 347                         ref_fh_fsid_type = 0;
 348
 349                 /* make sure ref_fh type works for given export */
 350                 if (ref_fh_fsid_type == 1 &&
 351                     !(exp->ex_flags & NFSEXP_FSID)) {
 352                         /* if we don't have an fsid, we cannot provide one... */
 353                         ref_fh_fsid_type = 0;
 354                 }
 355         } else if (exp->ex_flags & NFSEXP_FSID)
 356                 ref_fh_fsid_type = 1;
 357
 358         if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
 359                 /* for newer device numbers, we must use a newer fsid format */
 360                 ref_fh_version = 1;
 361                 ref_fh_fsid_type = 3;
 362         }
 363         if (old_valid_dev(ex_dev) &&
 364             (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
 365                 /* must use type1 for smaller device numbers */
 366                 ref_fh_fsid_type = 0;
 367
 368         if (ref_fh == fhp)
 369                 fh_put(ref_fh);
 370
 371         if (fhp->fh_locked || fhp->fh_dentry) {
 372                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 373                         parent->d_name.name, dentry->d_name.name);
 374         }
 375         if (fhp->fh_maxsize < NFS_FHSIZE)
 376                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 377                        fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
 378
 379         fhp->fh_dentry = dget(dentry); /* our internal copy */
 380         fhp->fh_export = exp;
 381         cache_get(&exp->h);
 382
 383         if (ref_fh_version == 0xca) {
 384                 /* old style filehandle please */
 385                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 386                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 387                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 388                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 389                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 390                 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 391                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 392                 if (inode)
 393                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 394         } else {
 395                 int len;
 396                 fhp->fh_handle.fh_version = 1;
 397                 fhp->fh_handle.fh_auth_type = 0;
 398                 datap = fhp->fh_handle.fh_auth+0;
 399                 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
 400                 switch (ref_fh_fsid_type) {
 401                         case 0:
 402                                 /*
 403                                  * fsid_type 0:
 404                                  * 2byte major, 2byte minor, 4byte inode
 405                                  */
 406                                 mk_fsid_v0(datap, ex_dev,
 407                                         exp->ex_dentry->d_inode->i_ino);
 408                                 break;
 409                         case 1:
 410                                 /* fsid_type 1 == 4 bytes filesystem id */
 411                                 mk_fsid_v1(datap, exp->ex_fsid);
 412                                 break;
 413                         case 2:
 414                                 /*
 415                                  * fsid_type 2:
 416                                  * 4byte major, 4byte minor, 4byte inode
 417                                  */
 418                                 mk_fsid_v2(datap, ex_dev,
 419                                         exp->ex_dentry->d_inode->i_ino);
 420                                 break;
 421                         case 3:
 422                                 /*
 423                                  * fsid_type 3:
 424                                  * 4byte devicenumber, 4byte inode
 425                                  */
 426                                 mk_fsid_v3(datap, ex_dev,
 427                                         exp->ex_dentry->d_inode->i_ino);
 428                                 break;
 429                 }
 430                 len = key_len(ref_fh_fsid_type);
 431                 datap += len/4;
 432                 fhp->fh_handle.fh_size = 4 + len;
 433
 434                 if (inode) {
 435                         int size = (fhp->fh_maxsize-len-4)/4;
 436                         fhp->fh_handle.fh_fileid_type =
 437                                 _fh_update(dentry, exp, datap, &size);
 438                         fhp->fh_handle.fh_size += size*4;
 439                 }
 440                 if (fhp->fh_handle.fh_fileid_type == 255)
 441                         return nfserr_opnotsupp;
 442         }
 443
 444         nfsd_nr_verified++;
 445         return 0;
 446 }
 447
 448 /*
 449  * Update file handle information after changing a dentry.
 450  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 451  */
 452 int
 453 fh_update(struct svc_fh *fhp)
 454 {
 455         struct dentry *dentry;
 456         __u32 *datap;
 457
 458         if (!fhp->fh_dentry)
 459                 goto out_bad;
 460
 461         dentry = fhp->fh_dentry;
 462         if (!dentry->d_inode)
 463                 goto out_negative;
 464         if (fhp->fh_handle.fh_version != 1) {
 465                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 466         } else {
 467                 int size;
 468                 if (fhp->fh_handle.fh_fileid_type != 0)
 469                         goto out_uptodate;
 470                 datap = fhp->fh_handle.fh_auth+
 471                         fhp->fh_handle.fh_size/4 -1;
 472                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 473                 fhp->fh_handle.fh_fileid_type =
 474                         _fh_update(dentry, fhp->fh_export, datap, &size);
 475                 fhp->fh_handle.fh_size += size*4;
 476                 if (fhp->fh_handle.fh_fileid_type == 255)
 477                         return nfserr_opnotsupp;
 478         }
 479 out:
 480         return 0;
 481
 482 out_bad:
 483         printk(KERN_ERR "fh_update: fh not verified!\n");
 484         goto out;
 485 out_negative:
 486         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 487                 dentry->d_parent->d_name.name, dentry->d_name.name);
 488         goto out;
 489 out_uptodate:
 490         printk(KERN_ERR "fh_update: %s/%s already up-to-date!\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                 svc_export_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 }