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                         goto out;
 147
 148                 error = nfserr_stale;
 149                 if (!exp || IS_ERR(exp))
 150                         goto out;
 151
 152                 /* Check if the request originated from a secure port. */
 153                 error = nfserr_perm;
 154                 if (!rqstp->rq_secure && EX_SECURE(exp)) {
 155                         printk(KERN_WARNING
 156                                "nfsd: request from insecure port (%08x:%d)!\n",
 157                                ntohl(rqstp->rq_addr.sin_addr.s_addr),
 158                                ntohs(rqstp->rq_addr.sin_port));
 159                         goto out;
 160                 }
 161
 162                 /* Set user creds for this exportpoint */
 163                 error = nfsd_setuser(rqstp, exp);
 164                 if (error) {
 165                         error = nfserrno(error);
 166                         goto out;
 167                 }
 168
 169                 /*
 170                  * Look up the dentry using the NFS file handle.
 171                  */
 172                 error = nfserr_stale;
 173                 if (rqstp->rq_vers > 2)
 174                         error = nfserr_badhandle;
 175
 176                 if (fh->fh_version != 1) {
 177                         tfh[0] = fh->ofh_ino;
 178                         tfh[1] = fh->ofh_generation;
 179                         tfh[2] = fh->ofh_dirino;
 180                         datap = tfh;
 181                         data_left = 3;
 182                         if (fh->ofh_dirino == 0)
 183                                 fileid_type = 1;
 184                         else
 185                                 fileid_type = 2;
 186                 } else
 187                         fileid_type = fh->fh_fileid_type;
 188
 189                 if (fileid_type == 0)
 190                         dentry = dget(exp->ex_dentry);
 191                 else {
 192                         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 193                                 dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
 194                                                              datap, data_left,
 195                                                              fileid_type,
 196                                                              nfsd_acceptable, exp);
 197                 }
 198                 if (dentry == NULL)
 199                         goto out;
 200                 if (IS_ERR(dentry)) {
 201                         if (PTR_ERR(dentry) != -EINVAL)
 202                                 error = nfserrno(PTR_ERR(dentry));
 203                         goto out;
 204                 }
 205 #ifdef NFSD_PARANOIA
 206                 if (S_ISDIR(dentry->d_inode->i_mode) &&
 207                     (dentry->d_flags & DCACHE_DISCONNECTED)) {
 208                         printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
 209                                dentry->d_parent->d_name.name, dentry->d_name.name);
 210                 }
 211 #endif
 212
 213                 fhp->fh_dentry = dentry;
 214                 fhp->fh_export = exp;
 215                 nfsd_nr_verified++;
 216         } else {
 217                 /* just rechecking permissions
 218                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
 219                  */
 220                 dprintk("nfsd: fh_verify - just checking\n");
 221                 dentry = fhp->fh_dentry;
 222                 exp = fhp->fh_export;
 223         }
 224         cache_get(&exp->h);
 225
 226         inode = dentry->d_inode;
 227
 228
 229         /* Type check. The correct error return for type mismatches
 230          * does not seem to be generally agreed upon. SunOS seems to
 231          * use EISDIR if file isn't S_IFREG; a comment in the NFSv3
 232          * spec says this is incorrect (implementation notes for the
 233          * write call).
 234          */
 235
 236         /* Type can be negative when creating hardlinks - not to a dir */
 237         if (type > 0 && (inode->i_mode & S_IFMT) != type) {
 238                 if (rqstp->rq_vers == 4 && (inode->i_mode & S_IFMT) == S_IFLNK)
 239                         error = nfserr_symlink;
 240                 else if (type == S_IFDIR)
 241                         error = nfserr_notdir;
 242                 else if ((inode->i_mode & S_IFMT) == S_IFDIR)
 243                         error = nfserr_isdir;
 244                 else
 245                         error = nfserr_inval;
 246                 goto out;
 247         }
 248         if (type < 0 && (inode->i_mode & S_IFMT) == -type) {
 249                 if (rqstp->rq_vers == 4 && (inode->i_mode & S_IFMT) == S_IFLNK)
 250                         error = nfserr_symlink;
 251                 else if (type == -S_IFDIR)
 252                         error = nfserr_isdir;
 253                 else
 254                         error = nfserr_notdir;
 255                 goto out;
 256         }
 257
 258         /* Finally, check access permissions. */
 259         error = nfsd_permission(exp, dentry, access);
 260
 261 #ifdef NFSD_PARANOIA_EXTREME
 262         if (error) {
 263                 printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n",
 264                        dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24));
 265         }
 266 #endif
 267 out:
 268         if (exp && !IS_ERR(exp))
 269                 exp_put(exp);
 270         if (error == nfserr_stale)
 271                 nfsdstats.fh_stale++;
 272         return error;
 273 }
 274
 275
 276 /*
 277  * Compose a file handle for an NFS reply.
 278  *
 279  * Note that when first composed, the dentry may not yet have
 280  * an inode.  In this case a call to fh_update should be made
 281  * before the fh goes out on the wire ...
 282  */
 283 inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
 284                       __u32 *datap, int *maxsize)
 285 {
 286         struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
 287
 288         if (dentry == exp->ex_dentry) {
 289                 *maxsize = 0;
 290                 return 0;
 291         }
 292
 293         return CALL(nop,encode_fh)(dentry, datap, maxsize,
 294                           !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
 295 }
 296
 297 /*
 298  * for composing old style file handles
 299  */
 300 inline void _fh_update_old(struct dentry *dentry, struct svc_export *exp,
 301                            struct knfsd_fh *fh)
 302 {
 303         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 304         fh->ofh_generation = dentry->d_inode->i_generation;
 305         if (S_ISDIR(dentry->d_inode->i_mode) ||
 306             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 307                 fh->ofh_dirino = 0;
 308 }
 309
 310 int
 311 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh)
 312 {
 313         /* ref_fh is a reference file handle.
 314          * if it is non-null, then we should compose a filehandle which is
 315          * of the same version, where possible.
 316          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
 317          * Then create a 32byte filehandle using nfs_fhbase_old
 318          *
 319          */
 320
 321         u8 ref_fh_version = 0;
 322         u8 ref_fh_fsid_type = 0;
 323         struct inode * inode = dentry->d_inode;
 324         struct dentry *parent = dentry->d_parent;
 325         __u32 *datap;
 326         dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
 327
 328         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
 329                 MAJOR(ex_dev), MINOR(ex_dev),
 330                 (long) exp->ex_dentry->d_inode->i_ino,
 331                 parent->d_name.name, dentry->d_name.name,
 332                 (inode ? inode->i_ino : 0));
 333
 334         if (ref_fh) {
 335                 ref_fh_version = ref_fh->fh_handle.fh_version;
 336                 if (ref_fh_version == 0xca)
 337                         ref_fh_fsid_type = 0;
 338                 else
 339                         ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
 340                 if (ref_fh_fsid_type > 3)
 341                         ref_fh_fsid_type = 0;
 342         }
 343         /* make sure ref_fh type works for given export */
 344         if (ref_fh_fsid_type == 1 &&
 345             !(exp->ex_flags & NFSEXP_FSID)) {
 346                 /* if we don't have an fsid, we cannot provide one... */
 347                 ref_fh_fsid_type = 0;
 348         }
 349         if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
 350                 /* for newer device numbers, we must use a newer fsid format */
 351                 ref_fh_version = 1;
 352                 ref_fh_fsid_type = 3;
 353         }
 354         if (old_valid_dev(ex_dev) &&
 355             (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
 356                 /* must use type1 for smaller device numbers */
 357                 ref_fh_fsid_type = 0;
 358
 359         if (ref_fh == fhp)
 360                 fh_put(ref_fh);
 361
 362         if (fhp->fh_locked || fhp->fh_dentry) {
 363                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
 364                         parent->d_name.name, dentry->d_name.name);
 365         }
 366         if (fhp->fh_maxsize < NFS_FHSIZE)
 367                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
 368                        fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
 369
 370         fhp->fh_dentry = dget(dentry); /* our internal copy */
 371         fhp->fh_export = exp;
 372         cache_get(&exp->h);
 373
 374         if (ref_fh_version == 0xca) {
 375                 /* old style filehandle please */
 376                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
 377                 fhp->fh_handle.fh_size = NFS_FHSIZE;
 378                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
 379                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
 380                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
 381                 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
 382                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
 383                 if (inode)
 384                         _fh_update_old(dentry, exp, &fhp->fh_handle);
 385         } else {
 386                 int len;
 387                 fhp->fh_handle.fh_version = 1;
 388                 fhp->fh_handle.fh_auth_type = 0;
 389                 datap = fhp->fh_handle.fh_auth+0;
 390                 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
 391                 switch (ref_fh_fsid_type) {
 392                         case 0:
 393                                 /*
 394                                  * fsid_type 0:
 395                                  * 2byte major, 2byte minor, 4byte inode
 396                                  */
 397                                 mk_fsid_v0(datap, ex_dev,
 398                                         exp->ex_dentry->d_inode->i_ino);
 399                                 break;
 400                         case 1:
 401                                 /* fsid_type 1 == 4 bytes filesystem id */
 402                                 mk_fsid_v1(datap, exp->ex_fsid);
 403                                 break;
 404                         case 2:
 405                                 /*
 406                                  * fsid_type 2:
 407                                  * 4byte major, 4byte minor, 4byte inode
 408                                  */
 409                                 mk_fsid_v2(datap, ex_dev,
 410                                         exp->ex_dentry->d_inode->i_ino);
 411                                 break;
 412                         case 3:
 413                                 /*
 414                                  * fsid_type 3:
 415                                  * 4byte devicenumber, 4byte inode
 416                                  */
 417                                 mk_fsid_v3(datap, ex_dev,
 418                                         exp->ex_dentry->d_inode->i_ino);
 419                                 break;
 420                 }
 421                 len = key_len(ref_fh_fsid_type);
 422                 datap += len/4;
 423                 fhp->fh_handle.fh_size = 4 + len;
 424
 425                 if (inode) {
 426                         int size = (fhp->fh_maxsize-len-4)/4;
 427                         fhp->fh_handle.fh_fileid_type =
 428                                 _fh_update(dentry, exp, datap, &size);
 429                         fhp->fh_handle.fh_size += size*4;
 430                 }
 431                 if (fhp->fh_handle.fh_fileid_type == 255)
 432                         return nfserr_opnotsupp;
 433         }
 434
 435         nfsd_nr_verified++;
 436         return 0;
 437 }
 438
 439 /*
 440  * Update file handle information after changing a dentry.
 441  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 442  */
 443 int
 444 fh_update(struct svc_fh *fhp)
 445 {
 446         struct dentry *dentry;
 447         __u32 *datap;
 448
 449         if (!fhp->fh_dentry)
 450                 goto out_bad;
 451
 452         dentry = fhp->fh_dentry;
 453         if (!dentry->d_inode)
 454                 goto out_negative;
 455         if (fhp->fh_handle.fh_version != 1) {
 456                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
 457         } else {
 458                 int size;
 459                 if (fhp->fh_handle.fh_fileid_type != 0)
 460                         goto out_uptodate;
 461                 datap = fhp->fh_handle.fh_auth+
 462                         fhp->fh_handle.fh_size/4 -1;
 463                 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
 464                 fhp->fh_handle.fh_fileid_type =
 465                         _fh_update(dentry, fhp->fh_export, datap, &size);
 466                 fhp->fh_handle.fh_size += size*4;
 467                 if (fhp->fh_handle.fh_fileid_type == 255)
 468                         return nfserr_opnotsupp;
 469         }
 470 out:
 471         return 0;
 472
 473 out_bad:
 474         printk(KERN_ERR "fh_update: fh not verified!\n");
 475         goto out;
 476 out_negative:
 477         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
 478                 dentry->d_parent->d_name.name, dentry->d_name.name);
 479         goto out;
 480 out_uptodate:
 481         printk(KERN_ERR "fh_update: %s/%s already up-to-date!\n",
 482                 dentry->d_parent->d_name.name, dentry->d_name.name);
 483         goto out;
 484 }
 485
 486 /*
 487  * Release a file handle.
 488  */
 489 void
 490 fh_put(struct svc_fh *fhp)
 491 {
 492         struct dentry * dentry = fhp->fh_dentry;
 493         struct svc_export * exp = fhp->fh_export;
 494         if (dentry) {
 495                 fh_unlock(fhp);
 496                 fhp->fh_dentry = NULL;
 497                 dput(dentry);
 498 #ifdef CONFIG_NFSD_V3
 499                 fhp->fh_pre_saved = 0;
 500                 fhp->fh_post_saved = 0;
 501 #endif
 502                 nfsd_nr_put++;
 503         }
 504         if (exp) {
 505                 svc_export_put(&exp->h, &svc_export_cache);
 506                 fhp->fh_export = NULL;
 507         }
 508         return;
 509 }
 510
 511 /*
 512  * Shorthand for dprintk()'s
 513  */
 514 char * SVCFH_fmt(struct svc_fh *fhp)
 515 {
 516         struct knfsd_fh *fh = &fhp->fh_handle;
 517
 518         static char buf[80];
 519         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
 520                 fh->fh_size,
 521                 fh->fh_base.fh_pad[0],
 522                 fh->fh_base.fh_pad[1],
 523                 fh->fh_base.fh_pad[2],
 524                 fh->fh_base.fh_pad[3],
 525                 fh->fh_base.fh_pad[4],
 526                 fh->fh_base.fh_pad[5]);
 527         return buf;
 528 }