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/fs.h>
  14 #include <linux/unistd.h>
  15 #include <linux/string.h>
  16 #include <linux/stat.h>
  17 #include <linux/dcache.h>
  18 #include <linux/exportfs.h>
  19 #include <linux/mount.h>
  20
  21 #include <linux/sunrpc/clnt.h>
  22 #include <linux/sunrpc/svc.h>
  23 #include <linux/sunrpc/svcauth_gss.h>
  24 #include <linux/nfsd/nfsd.h>
  25 #include "auth.h"
  26
  27 #define NFSDDBG_FACILITY                NFSDDBG_FH
  28
  29
  30 static int nfsd_nr_verified;
  31 static int nfsd_nr_put;
  32
  33 /*
  34  * our acceptability function.
  35  * if NOSUBTREECHECK, accept anything
  36  * if not, require that we can walk up to exp->ex_dentry
  37  * doing some checks on the 'x' bits
  38  */
  39 static int nfsd_acceptable(void *expv, struct dentry *dentry)
  40 {
  41         struct svc_export *exp = expv;
  42         int rv;
  43         struct dentry *tdentry;
  44         struct dentry *parent;
  45
  46         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
  47                 return 1;
  48
  49         tdentry = dget(dentry);
  50         while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
  51                 /* make sure parents give x permission to user */
  52                 int err;
  53                 parent = dget_parent(tdentry);
  54                 err = permission(parent->d_inode, MAY_EXEC, NULL);
  55                 if (err < 0) {
  56                         dput(parent);
  57                         break;
  58                 }
  59                 dput(tdentry);
  60                 tdentry = parent;
  61         }
  62         if (tdentry != exp->ex_path.dentry)
  63                 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
  64         rv = (tdentry == exp->ex_path.dentry);
  65         dput(tdentry);
  66         return rv;
  67 }
  68
  69 /* Type check. The correct error return for type mismatches does not seem to be
  70  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
  71  * comment in the NFSv3 spec says this is incorrect (implementation notes for
  72  * the write call).
  73  */
  74 static inline __be32
  75 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
  76 {
  77         /* Type can be negative when creating hardlinks - not to a dir */
  78         if (type > 0 && (mode & S_IFMT) != type) {
  79                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  80                         return nfserr_symlink;
  81                 else if (type == S_IFDIR)
  82                         return nfserr_notdir;
  83                 else if ((mode & S_IFMT) == S_IFDIR)
  84                         return nfserr_isdir;
  85                 else
  86                         return nfserr_inval;
  87         }
  88         if (type < 0 && (mode & S_IFMT) == -type) {
  89                 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
  90                         return nfserr_symlink;
  91                 else if (type == -S_IFDIR)
  92                         return nfserr_isdir;
  93                 else
  94                         return nfserr_notdir;
  95         }
  96         return 0;
  97 }
  98
  99 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
 100                                           struct svc_export *exp)
 101 {
 102         /* Check if the request originated from a secure port. */
 103         if (!rqstp->rq_secure && EX_SECURE(exp)) {
 104                 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 105                 dprintk(KERN_WARNING
 106                        "nfsd: request from insecure port %s!\n",
 107                        svc_print_addr(rqstp, buf, sizeof(buf)));
 108                 return nfserr_perm;
 109         }
 110
 111         /* Set user creds for this exportpoint */
 112         return nfserrno(nfsd_setuser(rqstp, exp));
 113 }
 114
 115 /*
 116  * Perform sanity checks on the dentry in a client's file handle.
 117  *
 118  * Note that the file handle dentry may need to be freed even after
 119  * an error return.
 120  *
 121  * This is only called at the start of an nfsproc call, so fhp points to
 122  * a svc_fh which is all 0 except for the over-the-wire file handle.
 123  */
 124 __be32
 125 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
 126 {
 127         struct knfsd_fh *fh = &fhp->fh_handle;
 128         struct svc_export *exp = NULL;
 129         struct dentry   *dentry;
 130         __be32          error = 0;
 131
 132         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
 133
 134         if (!fhp->fh_dentry) {
 135                 struct fid *fid = NULL, sfid;
 136                 int fileid_type;
 137                 int data_left = fh->fh_size/4;
 138
 139                 error = nfserr_stale;
 140                 if (rqstp->rq_vers > 2)
 141                         error = nfserr_badhandle;
 142                 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
 143                         return nfserr_nofilehandle;
 144
 145                 if (fh->fh_version == 1) {
 146                         int len;
 147                         if (--data_left<0) goto out;
 148                         switch (fh->fh_auth_type) {
 149                         case 0: break;
 150                         default: goto out;
 151                         }
 152                         len = key_len(fh->fh_fsid_type) / 4;
 153                         if (len == 0) goto out;
 154                         if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
 155                                 /* deprecated, convert to type 3 */
 156                                 len = key_len(FSID_ENCODE_DEV)/4;
 157                                 fh->fh_fsid_type = FSID_ENCODE_DEV;
 158                                 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
 159                                 fh->fh_fsid[1] = fh->fh_fsid[2];
 160                         }
 161                         if ((data_left -= len)<0) goto out;
 162                         exp = rqst_exp_find(rqstp, fh->fh_fsid_type,
 163                                             fh->fh_auth);
 164                         fid = (struct fid *)(fh->fh_auth + len);
 165                 } else {
 166                         __u32 tfh[2];
 167                         dev_t xdev;
 168                         ino_t xino;
 169                         if (fh->fh_size != NFS_FHSIZE)
 170                                 goto out;
 171                         /* assume old filehandle format */
 172                         xdev = old_decode_dev(fh->ofh_xdev);
 173                         xino = u32_to_ino_t(fh->ofh_xino);
 174                         mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
 175                         exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
 176                 }
 177
 178                 error = nfserr_stale;
 179                 if (PTR_ERR(exp) == -ENOENT)
 180                         goto out;
 181
 182                 if (IS_ERR(exp)) {
 183                         error = nfserrno(PTR_ERR(exp));
 184                         goto out;
 185                 }
 186
 187                 error = nfsd_setuser_and_check_port(rqstp, exp);
 188                 if (error)
 189                         goto out;
 190
 191                 /*
 192                  * Look up the dentry using the NFS file handle.
 193                  */
 194                 error = nfserr_stale;
 195                 if (rqstp->rq_vers > 2)
 196                         error = nfserr_badhandle;
 197
 198                 if (fh->fh_version != 1) {
 199                         sfid.i32.ino = fh->ofh_ino;
 200                         sfid.i32.gen = fh->ofh_generation;
 201                         sfid.i32.parent_ino = fh->ofh_dirino;
 202                         fid = &sfid;
 203                         data_left = 3;
 204                         if (fh->ofh_dirino == 0)
 205                                 fileid_type = FILEID_INO32_GEN;
 206                         else
 207                                 fileid_type = FILEID_INO32_GEN_PARENT;
 208                 } else
 209                         fileid_type = fh->fh_fileid_type;
 210
 211                 if (fileid_type == FILEID_ROOT)
 212                         dentry = dget(exp->ex_path.dentry);
 213                 else {
 214                         dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
 215                                         data_left, fileid_type,
 216                                         nfsd_acceptable, exp);
 217                 }
 218                 if (dentry == NULL)
 219                         goto out;
 220                 if (IS_ERR(dentry)) {
 221                         if (PTR_ERR(dentry) != -EINVAL)
 222                                 error = nfserrno(PTR_ERR(dentry));
 223                         goto out;
 224                 }
 225
 226                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 227                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 228                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 229                                dentry->d_parent->d_name.name, dentry->d_name.name);
 230                 }
 231
 232                 fhp->fh_dentry = dentry;
 233                 fhp->fh_export = exp;
 234                 nfsd_nr_verified++;
 235         } else {
 236                 /*
 237                  * just rechecking permissions
 238                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create
 239                  * does as well)
 240                  */
 241                 dprintk("nfsd: fh_verify - just checking\n");
 242                 dentry = fhp->fh_dentry;
 243                 exp = fhp->fh_export;
 244                 /*
 245                  * Set user creds for this exportpoint; necessary even
 246                  * in the "just checking" case because this may be a
 247                  * filehandle that was created by fh_compose, and that
 248                  * is about to be used in another nfsv4 compound
 249                  * operation.
 250                  */
 251                 error = nfsd_setuser_and_check_port(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         if (!(access & MAY_LOCK)) {
 263                 /*
 264                  * pseudoflavor restrictions are not enforced on NLM,
 265                  * which clients virtually always use auth_sys for,
 266                  * even while using RPCSEC_GSS for NFS.
 267                  */
 268                 error = check_nfsd_access(exp, rqstp);
 269                 if (error)
 270                         goto out;
 271         }
 272
 273         /* Finally, check access permissions. */
 274         error = nfsd_permission(rqstp, exp, dentry, access);
 275
 276         if (error) {
 277                 dprintk("fh_verify: %s/%s permission failure, "
 278                         "acc=%x, error=%d\n",
 279                         dentry->d_parent->d_name.name,
 280                         dentry->d_name.name,
 281                         access, ntohl(error));
 282         }
 283 out:
 284         if (exp && !IS_ERR(exp))
 285                 exp_put(exp);
 286         if (error == nfserr_stale)
 287                 nfsdstats.fh_stale++;
 288         return error;
 289 }
 290
 291
 292 /*
 293  * Compose a file handle for an NFS reply.
 294  *
 295  * Note that when first composed, the dentry may not yet have
 296  * an inode.  In this case a call to fh_update should be made
 297  * before the fh goes out on the wire ...
 298  */
 299 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
 300                 struct dentry *dentry)
 301 {
 302         if (dentry != exp->ex_path.dentry) {
 303                 struct fid *fid = (struct fid *)
 304                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
 305                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 306                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
 307
 308                 fhp->fh_handle.fh_fileid_type =
 309                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
 310                 fhp->fh_handle.fh_size += maxsize * 4;
 311         } else {
 312                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
 313         }
 314 }
 315
 316 /*
 317  * for composing old style file handles
 318  */
 319 static inline void _fh_update_old(struct dentry *dentry,
 320                                   struct svc_export *exp,
 321                                   struct knfsd_fh *fh)
 322 {
 323         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 324         fh->ofh_generation = dentry->d_inode->i_generation;
 325         if (S_ISDIR(dentry->d_inode->i_mode) ||
 326             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 327                 fh->ofh_dirino = 0;
 328 }
 329
 330 __be32
 331 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
 332            struct svc_fh *ref_fh)
 333 {
 334         /* ref_fh is a reference file handle.
 335          * if it is non-null and for the same filesystem, then we should compose
 336          * a filehandle which is of the same version, where possible.
 337          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 338          * Then create a 32byte filehandle using nfs_fhbase_old
 339          *
 340          */
 341
 342         u8 version;
 343         u8 fsid_type = 0;
 344         struct inode * inode = dentry->d_inode;
 345         struct dentry *parent = dentry->d_parent;
 346         __u32 *datap;
 347         dev_t ex_dev = exp->ex_path.dentry->d_inode->i_sb->s_dev;
 348         int root_export = (exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root);
 349
 350         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 351                 MAJOR(ex_dev), MINOR(ex_dev),
 352                 (long) exp->ex_path.dentry->d_inode->i_ino,
 353                 parent->d_name.name, dentry->d_name.name,
 354                 (inode ? inode->i_ino : 0));
 355
 356         /* Choose filehandle version and fsid type based on
 357          * the reference filehandle (if it is in the same export)
 358          * or the export options.
 359          */
 360  retry:
 361         version = 1;
 362         if (ref_fh && ref_fh->fh_export == exp) {
 363                 version = ref_fh->fh_handle.fh_version;
 364                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
 365
 366                 if (ref_fh == fhp)
 367                         fh_put(ref_fh);
 368                 ref_fh = NULL;
 369
 370                 switch (version) {
 371                 case 0xca:
 372                         fsid_type = FSID_DEV;
 373                         break;
 374                 case 1:
 375                         break;
 376                 default:
 377                         goto retry;
 378                 }
 379
 380                 /* Need to check that this type works for this
 381                  * export point.  As the fsid -> filesystem mapping
 382                  * was guided by user-space, there is no guarantee
 383                  * that the filesystem actually supports that fsid
 384                  * type. If it doesn't we loop around again without
 385                  * ref_fh set.
 386                  */
 387                 switch(fsid_type) {
 388                 case FSID_DEV:
 389                         if (!old_valid_dev(ex_dev))
 390                                 goto retry;
 391                         /* FALL THROUGH */
 392                 case FSID_MAJOR_MINOR:
 393                 case FSID_ENCODE_DEV:
 394                         if (!(exp->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
 395                               & FS_REQUIRES_DEV))
 396                                 goto retry;
 397                         break;
 398                 case FSID_NUM:
 399                         if (! (exp->ex_flags & NFSEXP_FSID))
 400                                 goto retry;
 401                         break;
 402                 case FSID_UUID8:
 403                 case FSID_UUID16:
 404                         if (!root_export)
 405                                 goto retry;
 406                         /* fall through */
 407                 case FSID_UUID4_INUM:
 408                 case FSID_UUID16_INUM:
 409                         if (exp->ex_uuid == NULL)
 410                                 goto retry;
 411                         break;
 412                 }
 413         } else if (exp->ex_uuid) {
 414                 if (fhp->fh_maxsize >= 64) {
 415                         if (root_export)
 416                                 fsid_type = FSID_UUID16;
 417                         else
 418                                 fsid_type = FSID_UUID16_INUM;
 419                 } else {
 420                         if (root_export)
 421                                 fsid_type = FSID_UUID8;
 422                         else
 423                                 fsid_type = FSID_UUID4_INUM;
 424                 }
 425         } else if (exp->ex_flags & NFSEXP_FSID)
 426                 fsid_type = FSID_NUM;
 427         else if (!old_valid_dev(ex_dev))
 428                 /* for newer device numbers, we must use a newer fsid format */
 429                 fsid_type = FSID_ENCODE_DEV;
 430         else
 431                 fsid_type = FSID_DEV;
 432
 433         if (ref_fh == fhp)
 434                 fh_put(ref_fh);
 435
 436         if (fhp->fh_locked || fhp->fh_dentry) {
 437                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 438                        parent->d_name.name, dentry->d_name.name);
 439         }
 440         if (fhp->fh_maxsize < NFS_FHSIZE)
 441                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 442                        fhp->fh_maxsize,
 443                        parent->d_name.name, dentry->d_name.name);
 444
 445         fhp->fh_dentry = dget(dentry); /* our internal copy */
 446         fhp->fh_export = exp;
 447         cache_get(&exp->h);
 448
 449         if (version == 0xca) {
 450                 /* old style filehandle please */
 451                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 452                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 453                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 454                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 455                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 456                 fhp->fh_handle.ofh_xino =
 457                         ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
 458                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 459                 if (inode)
 460                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 461         } else {
 462                 int len;
 463                 fhp->fh_handle.fh_version = 1;
 464                 fhp->fh_handle.fh_auth_type = 0;
 465                 datap = fhp->fh_handle.fh_auth+0;
 466                 fhp->fh_handle.fh_fsid_type = fsid_type;
 467                 mk_fsid(fsid_type, datap, ex_dev,
 468                         exp->ex_path.dentry->d_inode->i_ino,
 469                         exp->ex_fsid, exp->ex_uuid);
 470
 471                 len = key_len(fsid_type);
 472                 datap += len/4;
 473                 fhp->fh_handle.fh_size = 4 + len;
 474
 475                 if (inode)
 476                         _fh_update(fhp, exp, dentry);
 477                 if (fhp->fh_handle.fh_fileid_type == 255)
 478                         return nfserr_opnotsupp;
 479         }
 480
 481         nfsd_nr_verified++;
 482         return 0;
 483 }
 484
 485 /*
 486  * Update file handle information after changing a dentry.
 487  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 488  */
 489 __be32
 490 fh_update(struct svc_fh *fhp)
 491 {
 492         struct dentry *dentry;
 493
 494         if (!fhp->fh_dentry)
 495                 goto out_bad;
 496
 497         dentry = fhp->fh_dentry;
 498         if (!dentry->d_inode)
 499                 goto out_negative;
 500         if (fhp->fh_handle.fh_version != 1) {
 501                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 502         } else {
 503                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
 504                         goto out;
 505
 506                 _fh_update(fhp, fhp->fh_export, dentry);
 507                 if (fhp->fh_handle.fh_fileid_type == 255)
 508                         return nfserr_opnotsupp;
 509         }
 510 out:
 511         return 0;
 512
 513 out_bad:
 514         printk(KERN_ERR "fh_update: fh not verified!\n");
 515         goto out;
 516 out_negative:
 517         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 518                 dentry->d_parent->d_name.name, dentry->d_name.name);
 519         goto out;
 520 }
 521
 522 /*
 523  * Release a file handle.
 524  */
 525 void
 526 fh_put(struct svc_fh *fhp)
 527 {
 528         struct dentry * dentry = fhp->fh_dentry;
 529         struct svc_export * exp = fhp->fh_export;
 530         if (dentry) {
 531                 fh_unlock(fhp);
 532                 fhp->fh_dentry = NULL;
 533                 dput(dentry);
 534 #ifdef CONFIG_NFSD_V3
 535                 fhp->fh_pre_saved = 0;
 536                 fhp->fh_post_saved = 0;
 537 #endif
 538                 nfsd_nr_put++;
 539         }
 540         if (exp) {
 541                 cache_put(&exp->h, &svc_export_cache);
 542                 fhp->fh_export = NULL;
 543         }
 544         return;
 545 }
 546
 547 /*
 548  * Shorthand for dprintk()'s
 549  */
 550 char * SVCFH_fmt(struct svc_fh *fhp)
 551 {
 552         struct knfsd_fh *fh = &fhp->fh_handle;
 553
 554         static char buf[80];
 555         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 556                 fh->fh_size,
 557                 fh->fh_base.fh_pad[0],
 558                 fh->fh_base.fh_pad[1],
 559                 fh->fh_base.fh_pad[2],
 560                 fh->fh_base.fh_pad[3],
 561                 fh->fh_base.fh_pad[4],
 562                 fh->fh_base.fh_pad[5]);
 563         return buf;
 564 }
 565
 566 enum fsid_source fsid_source(struct svc_fh *fhp)
 567 {
 568         if (fhp->fh_handle.fh_version != 1)
 569                 return FSIDSOURCE_DEV;
 570         switch(fhp->fh_handle.fh_fsid_type) {
 571         case FSID_DEV:
 572         case FSID_ENCODE_DEV:
 573         case FSID_MAJOR_MINOR:
 574                 if (fhp->fh_export->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
 575                     & FS_REQUIRES_DEV)
 576                         return FSIDSOURCE_DEV;
 577                 break;
 578         case FSID_NUM:
 579                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 580                         return FSIDSOURCE_FSID;
 581                 break;
 582         default:
 583                 break;
 584         }
 585         /* either a UUID type filehandle, or the filehandle doesn't
 586          * match the export.
 587          */
 588         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
 589                 return FSIDSOURCE_FSID;
 590         if (fhp->fh_export->ex_uuid)
 591                 return FSIDSOURCE_UUID;
 592         return FSIDSOURCE_DEV;
 593 }