1eb771d79cca09a51326541dc76f3db3405f9245
[sfrench/cifs-2.6.git] / 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 }