Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh...
[linux-2.6] / 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  * Use the given filehandle to look up the corresponding export and
117  * dentry.  On success, the results are used to set fh_export and
118  * fh_dentry.
119  */
120 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
121 {
122         struct knfsd_fh *fh = &fhp->fh_handle;
123         struct fid *fid = NULL, sfid;
124         struct svc_export *exp;
125         struct dentry *dentry;
126         int fileid_type;
127         int data_left = fh->fh_size/4;
128         __be32 error;
129
130         error = nfserr_stale;
131         if (rqstp->rq_vers > 2)
132                 error = nfserr_badhandle;
133         if (rqstp->rq_vers == 4 && fh->fh_size == 0)
134                 return nfserr_nofilehandle;
135
136         if (fh->fh_version == 1) {
137                 int len;
138
139                 if (--data_left < 0)
140                         return error;
141                 if (fh->fh_auth_type != 0)
142                         return error;
143                 len = key_len(fh->fh_fsid_type) / 4;
144                 if (len == 0)
145                         return error;
146                 if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
147                         /* deprecated, convert to type 3 */
148                         len = key_len(FSID_ENCODE_DEV)/4;
149                         fh->fh_fsid_type = FSID_ENCODE_DEV;
150                         fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
151                         fh->fh_fsid[1] = fh->fh_fsid[2];
152                 }
153                 data_left -= len;
154                 if (data_left < 0)
155                         return error;
156                 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
157                 fid = (struct fid *)(fh->fh_auth + len);
158         } else {
159                 __u32 tfh[2];
160                 dev_t xdev;
161                 ino_t xino;
162
163                 if (fh->fh_size != NFS_FHSIZE)
164                         return error;
165                 /* assume old filehandle format */
166                 xdev = old_decode_dev(fh->ofh_xdev);
167                 xino = u32_to_ino_t(fh->ofh_xino);
168                 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
169                 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
170         }
171
172         error = nfserr_stale;
173         if (PTR_ERR(exp) == -ENOENT)
174                 return error;
175
176         if (IS_ERR(exp))
177                 return nfserrno(PTR_ERR(exp));
178
179         error = nfsd_setuser_and_check_port(rqstp, exp);
180         if (error)
181                 goto out;
182
183         /*
184          * Look up the dentry using the NFS file handle.
185          */
186         error = nfserr_stale;
187         if (rqstp->rq_vers > 2)
188                 error = nfserr_badhandle;
189
190         if (fh->fh_version != 1) {
191                 sfid.i32.ino = fh->ofh_ino;
192                 sfid.i32.gen = fh->ofh_generation;
193                 sfid.i32.parent_ino = fh->ofh_dirino;
194                 fid = &sfid;
195                 data_left = 3;
196                 if (fh->ofh_dirino == 0)
197                         fileid_type = FILEID_INO32_GEN;
198                 else
199                         fileid_type = FILEID_INO32_GEN_PARENT;
200         } else
201                 fileid_type = fh->fh_fileid_type;
202
203         if (fileid_type == FILEID_ROOT)
204                 dentry = dget(exp->ex_path.dentry);
205         else {
206                 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
207                                 data_left, fileid_type,
208                                 nfsd_acceptable, exp);
209         }
210         if (dentry == NULL)
211                 goto out;
212         if (IS_ERR(dentry)) {
213                 if (PTR_ERR(dentry) != -EINVAL)
214                         error = nfserrno(PTR_ERR(dentry));
215                 goto out;
216         }
217
218         if (S_ISDIR(dentry->d_inode->i_mode) &&
219                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
220                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
221                                 dentry->d_parent->d_name.name, dentry->d_name.name);
222         }
223
224         fhp->fh_dentry = dentry;
225         fhp->fh_export = exp;
226         nfsd_nr_verified++;
227         return 0;
228 out:
229         exp_put(exp);
230         return error;
231 }
232
233 /*
234  * Perform sanity checks on the dentry in a client's file handle.
235  *
236  * Note that the file handle dentry may need to be freed even after
237  * an error return.
238  *
239  * This is only called at the start of an nfsproc call, so fhp points to
240  * a svc_fh which is all 0 except for the over-the-wire file handle.
241  */
242 __be32
243 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
244 {
245         struct svc_export *exp;
246         struct dentry   *dentry;
247         __be32          error;
248
249         dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
250
251         if (!fhp->fh_dentry) {
252                 error = nfsd_set_fh_dentry(rqstp, fhp);
253                 if (error)
254                         goto out;
255                 dentry = fhp->fh_dentry;
256                 exp = fhp->fh_export;
257         } else {
258                 /*
259                  * just rechecking permissions
260                  * (e.g. nfsproc_create calls fh_verify, then nfsd_create
261                  * does as well)
262                  */
263                 dprintk("nfsd: fh_verify - just checking\n");
264                 dentry = fhp->fh_dentry;
265                 exp = fhp->fh_export;
266                 /*
267                  * Set user creds for this exportpoint; necessary even
268                  * in the "just checking" case because this may be a
269                  * filehandle that was created by fh_compose, and that
270                  * is about to be used in another nfsv4 compound
271                  * operation.
272                  */
273                 error = nfsd_setuser_and_check_port(rqstp, exp);
274                 if (error)
275                         goto out;
276         }
277
278         error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
279         if (error)
280                 goto out;
281
282         if (!(access & MAY_LOCK)) {
283                 /*
284                  * pseudoflavor restrictions are not enforced on NLM,
285                  * which clients virtually always use auth_sys for,
286                  * even while using RPCSEC_GSS for NFS.
287                  */
288                 error = check_nfsd_access(exp, rqstp);
289                 if (error)
290                         goto out;
291         }
292
293         /* Finally, check access permissions. */
294         error = nfsd_permission(rqstp, exp, dentry, access);
295
296         if (error) {
297                 dprintk("fh_verify: %s/%s permission failure, "
298                         "acc=%x, error=%d\n",
299                         dentry->d_parent->d_name.name,
300                         dentry->d_name.name,
301                         access, ntohl(error));
302         }
303 out:
304         if (error == nfserr_stale)
305                 nfsdstats.fh_stale++;
306         return error;
307 }
308
309
310 /*
311  * Compose a file handle for an NFS reply.
312  *
313  * Note that when first composed, the dentry may not yet have
314  * an inode.  In this case a call to fh_update should be made
315  * before the fh goes out on the wire ...
316  */
317 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
318                 struct dentry *dentry)
319 {
320         if (dentry != exp->ex_path.dentry) {
321                 struct fid *fid = (struct fid *)
322                         (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
323                 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
324                 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
325
326                 fhp->fh_handle.fh_fileid_type =
327                         exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
328                 fhp->fh_handle.fh_size += maxsize * 4;
329         } else {
330                 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
331         }
332 }
333
334 /*
335  * for composing old style file handles
336  */
337 static inline void _fh_update_old(struct dentry *dentry,
338                                   struct svc_export *exp,
339                                   struct knfsd_fh *fh)
340 {
341         fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
342         fh->ofh_generation = dentry->d_inode->i_generation;
343         if (S_ISDIR(dentry->d_inode->i_mode) ||
344             (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
345                 fh->ofh_dirino = 0;
346 }
347
348 __be32
349 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
350            struct svc_fh *ref_fh)
351 {
352         /* ref_fh is a reference file handle.
353          * if it is non-null and for the same filesystem, then we should compose
354          * a filehandle which is of the same version, where possible.
355          * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
356          * Then create a 32byte filehandle using nfs_fhbase_old
357          *
358          */
359
360         u8 version;
361         u8 fsid_type = 0;
362         struct inode * inode = dentry->d_inode;
363         struct dentry *parent = dentry->d_parent;
364         __u32 *datap;
365         dev_t ex_dev = exp->ex_path.dentry->d_inode->i_sb->s_dev;
366         int root_export = (exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root);
367
368         dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
369                 MAJOR(ex_dev), MINOR(ex_dev),
370                 (long) exp->ex_path.dentry->d_inode->i_ino,
371                 parent->d_name.name, dentry->d_name.name,
372                 (inode ? inode->i_ino : 0));
373
374         /* Choose filehandle version and fsid type based on
375          * the reference filehandle (if it is in the same export)
376          * or the export options.
377          */
378  retry:
379         version = 1;
380         if (ref_fh && ref_fh->fh_export == exp) {
381                 version = ref_fh->fh_handle.fh_version;
382                 fsid_type = ref_fh->fh_handle.fh_fsid_type;
383
384                 if (ref_fh == fhp)
385                         fh_put(ref_fh);
386                 ref_fh = NULL;
387
388                 switch (version) {
389                 case 0xca:
390                         fsid_type = FSID_DEV;
391                         break;
392                 case 1:
393                         break;
394                 default:
395                         goto retry;
396                 }
397
398                 /* Need to check that this type works for this
399                  * export point.  As the fsid -> filesystem mapping
400                  * was guided by user-space, there is no guarantee
401                  * that the filesystem actually supports that fsid
402                  * type. If it doesn't we loop around again without
403                  * ref_fh set.
404                  */
405                 switch(fsid_type) {
406                 case FSID_DEV:
407                         if (!old_valid_dev(ex_dev))
408                                 goto retry;
409                         /* FALL THROUGH */
410                 case FSID_MAJOR_MINOR:
411                 case FSID_ENCODE_DEV:
412                         if (!(exp->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
413                               & FS_REQUIRES_DEV))
414                                 goto retry;
415                         break;
416                 case FSID_NUM:
417                         if (! (exp->ex_flags & NFSEXP_FSID))
418                                 goto retry;
419                         break;
420                 case FSID_UUID8:
421                 case FSID_UUID16:
422                         if (!root_export)
423                                 goto retry;
424                         /* fall through */
425                 case FSID_UUID4_INUM:
426                 case FSID_UUID16_INUM:
427                         if (exp->ex_uuid == NULL)
428                                 goto retry;
429                         break;
430                 }
431         } else if (exp->ex_uuid) {
432                 if (fhp->fh_maxsize >= 64) {
433                         if (root_export)
434                                 fsid_type = FSID_UUID16;
435                         else
436                                 fsid_type = FSID_UUID16_INUM;
437                 } else {
438                         if (root_export)
439                                 fsid_type = FSID_UUID8;
440                         else
441                                 fsid_type = FSID_UUID4_INUM;
442                 }
443         } else if (exp->ex_flags & NFSEXP_FSID)
444                 fsid_type = FSID_NUM;
445         else if (!old_valid_dev(ex_dev))
446                 /* for newer device numbers, we must use a newer fsid format */
447                 fsid_type = FSID_ENCODE_DEV;
448         else
449                 fsid_type = FSID_DEV;
450
451         if (ref_fh == fhp)
452                 fh_put(ref_fh);
453
454         if (fhp->fh_locked || fhp->fh_dentry) {
455                 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
456                        parent->d_name.name, dentry->d_name.name);
457         }
458         if (fhp->fh_maxsize < NFS_FHSIZE)
459                 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
460                        fhp->fh_maxsize,
461                        parent->d_name.name, dentry->d_name.name);
462
463         fhp->fh_dentry = dget(dentry); /* our internal copy */
464         fhp->fh_export = exp;
465         cache_get(&exp->h);
466
467         if (version == 0xca) {
468                 /* old style filehandle please */
469                 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
470                 fhp->fh_handle.fh_size = NFS_FHSIZE;
471                 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
472                 fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
473                 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
474                 fhp->fh_handle.ofh_xino =
475                         ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
476                 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
477                 if (inode)
478                         _fh_update_old(dentry, exp, &fhp->fh_handle);
479         } else {
480                 int len;
481                 fhp->fh_handle.fh_version = 1;
482                 fhp->fh_handle.fh_auth_type = 0;
483                 datap = fhp->fh_handle.fh_auth+0;
484                 fhp->fh_handle.fh_fsid_type = fsid_type;
485                 mk_fsid(fsid_type, datap, ex_dev,
486                         exp->ex_path.dentry->d_inode->i_ino,
487                         exp->ex_fsid, exp->ex_uuid);
488
489                 len = key_len(fsid_type);
490                 datap += len/4;
491                 fhp->fh_handle.fh_size = 4 + len;
492
493                 if (inode)
494                         _fh_update(fhp, exp, dentry);
495                 if (fhp->fh_handle.fh_fileid_type == 255)
496                         return nfserr_opnotsupp;
497         }
498
499         nfsd_nr_verified++;
500         return 0;
501 }
502
503 /*
504  * Update file handle information after changing a dentry.
505  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
506  */
507 __be32
508 fh_update(struct svc_fh *fhp)
509 {
510         struct dentry *dentry;
511
512         if (!fhp->fh_dentry)
513                 goto out_bad;
514
515         dentry = fhp->fh_dentry;
516         if (!dentry->d_inode)
517                 goto out_negative;
518         if (fhp->fh_handle.fh_version != 1) {
519                 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
520         } else {
521                 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
522                         goto out;
523
524                 _fh_update(fhp, fhp->fh_export, dentry);
525                 if (fhp->fh_handle.fh_fileid_type == 255)
526                         return nfserr_opnotsupp;
527         }
528 out:
529         return 0;
530
531 out_bad:
532         printk(KERN_ERR "fh_update: fh not verified!\n");
533         goto out;
534 out_negative:
535         printk(KERN_ERR "fh_update: %s/%s still negative!\n",
536                 dentry->d_parent->d_name.name, dentry->d_name.name);
537         goto out;
538 }
539
540 /*
541  * Release a file handle.
542  */
543 void
544 fh_put(struct svc_fh *fhp)
545 {
546         struct dentry * dentry = fhp->fh_dentry;
547         struct svc_export * exp = fhp->fh_export;
548         if (dentry) {
549                 fh_unlock(fhp);
550                 fhp->fh_dentry = NULL;
551                 dput(dentry);
552 #ifdef CONFIG_NFSD_V3
553                 fhp->fh_pre_saved = 0;
554                 fhp->fh_post_saved = 0;
555 #endif
556                 nfsd_nr_put++;
557         }
558         if (exp) {
559                 cache_put(&exp->h, &svc_export_cache);
560                 fhp->fh_export = NULL;
561         }
562         return;
563 }
564
565 /*
566  * Shorthand for dprintk()'s
567  */
568 char * SVCFH_fmt(struct svc_fh *fhp)
569 {
570         struct knfsd_fh *fh = &fhp->fh_handle;
571
572         static char buf[80];
573         sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
574                 fh->fh_size,
575                 fh->fh_base.fh_pad[0],
576                 fh->fh_base.fh_pad[1],
577                 fh->fh_base.fh_pad[2],
578                 fh->fh_base.fh_pad[3],
579                 fh->fh_base.fh_pad[4],
580                 fh->fh_base.fh_pad[5]);
581         return buf;
582 }
583
584 enum fsid_source fsid_source(struct svc_fh *fhp)
585 {
586         if (fhp->fh_handle.fh_version != 1)
587                 return FSIDSOURCE_DEV;
588         switch(fhp->fh_handle.fh_fsid_type) {
589         case FSID_DEV:
590         case FSID_ENCODE_DEV:
591         case FSID_MAJOR_MINOR:
592                 if (fhp->fh_export->ex_path.dentry->d_inode->i_sb->s_type->fs_flags
593                     & FS_REQUIRES_DEV)
594                         return FSIDSOURCE_DEV;
595                 break;
596         case FSID_NUM:
597                 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
598                         return FSIDSOURCE_FSID;
599                 break;
600         default:
601                 break;
602         }
603         /* either a UUID type filehandle, or the filehandle doesn't
604          * match the export.
605          */
606         if (fhp->fh_export->ex_flags & NFSEXP_FSID)
607                 return FSIDSOURCE_FSID;
608         if (fhp->fh_export->ex_uuid)
609                 return FSIDSOURCE_UUID;
610         return FSIDSOURCE_DEV;
611 }