2 * NFS server file handle treatment.
4 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
5 * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
6 * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
7 * ... and again Southern-Winter 2001 to support export_operations
10 #include <linux/exportfs.h>
12 #include <linux/sunrpc/svcauth_gss.h>
17 #define NFSDDBG_FACILITY NFSDDBG_FH
21 * our acceptability function.
22 * if NOSUBTREECHECK, accept anything
23 * if not, require that we can walk up to exp->ex_dentry
24 * doing some checks on the 'x' bits
26 static int nfsd_acceptable(void *expv
, struct dentry
*dentry
)
28 struct svc_export
*exp
= expv
;
30 struct dentry
*tdentry
;
31 struct dentry
*parent
;
33 if (exp
->ex_flags
& NFSEXP_NOSUBTREECHECK
)
36 tdentry
= dget(dentry
);
37 while (tdentry
!= exp
->ex_path
.dentry
&& !IS_ROOT(tdentry
)) {
38 /* make sure parents give x permission to user */
40 parent
= dget_parent(tdentry
);
41 err
= inode_permission(parent
->d_inode
, MAY_EXEC
);
49 if (tdentry
!= exp
->ex_path
.dentry
)
50 dprintk("nfsd_acceptable failed at %p %s\n", tdentry
, tdentry
->d_name
.name
);
51 rv
= (tdentry
== exp
->ex_path
.dentry
);
56 /* Type check. The correct error return for type mismatches does not seem to be
57 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
58 * comment in the NFSv3 spec says this is incorrect (implementation notes for
62 nfsd_mode_check(struct svc_rqst
*rqstp
, umode_t mode
, int type
)
64 if (type
> 0 && (mode
& S_IFMT
) != type
) {
65 if (rqstp
->rq_vers
== 4 && (mode
& S_IFMT
) == S_IFLNK
)
66 return nfserr_symlink
;
67 else if (type
== S_IFDIR
)
69 else if ((mode
& S_IFMT
) == S_IFDIR
)
77 static __be32
nfsd_setuser_and_check_port(struct svc_rqst
*rqstp
,
78 struct svc_export
*exp
)
80 int flags
= nfsexp_flags(rqstp
, exp
);
82 /* Check if the request originated from a secure port. */
83 if (!rqstp
->rq_secure
&& !(flags
& NFSEXP_INSECURE_PORT
)) {
84 RPC_IFDEBUG(char buf
[RPC_MAX_ADDRBUFLEN
]);
86 "nfsd: request from insecure port %s!\n",
87 svc_print_addr(rqstp
, buf
, sizeof(buf
)));
91 /* Set user creds for this exportpoint */
92 return nfserrno(nfsd_setuser(rqstp
, exp
));
95 static inline __be32
check_pseudo_root(struct svc_rqst
*rqstp
,
96 struct dentry
*dentry
, struct svc_export
*exp
)
98 if (!(exp
->ex_flags
& NFSEXP_V4ROOT
))
101 * v2/v3 clients have no need for the V4ROOT export--they use
102 * the mount protocl instead; also, further V4ROOT checks may be
103 * in v4-specific code, in which case v2/v3 clients could bypass
106 if (!nfsd_v4client(rqstp
))
109 * We're exposing only the directories and symlinks that have to be
110 * traversed on the way to real exports:
112 if (unlikely(!S_ISDIR(dentry
->d_inode
->i_mode
) &&
113 !S_ISLNK(dentry
->d_inode
->i_mode
)))
116 * A pseudoroot export gives permission to access only one
117 * single directory; the kernel has to make another upcall
118 * before granting access to anything else under it:
120 if (unlikely(dentry
!= exp
->ex_path
.dentry
))
126 * Use the given filehandle to look up the corresponding export and
127 * dentry. On success, the results are used to set fh_export and
130 static __be32
nfsd_set_fh_dentry(struct svc_rqst
*rqstp
, struct svc_fh
*fhp
)
132 struct knfsd_fh
*fh
= &fhp
->fh_handle
;
133 struct fid
*fid
= NULL
, sfid
;
134 struct svc_export
*exp
;
135 struct dentry
*dentry
;
137 int data_left
= fh
->fh_size
/4;
140 error
= nfserr_stale
;
141 if (rqstp
->rq_vers
> 2)
142 error
= nfserr_badhandle
;
143 if (rqstp
->rq_vers
== 4 && fh
->fh_size
== 0)
144 return nfserr_nofilehandle
;
146 if (fh
->fh_version
== 1) {
151 if (fh
->fh_auth_type
!= 0)
153 len
= key_len(fh
->fh_fsid_type
) / 4;
156 if (fh
->fh_fsid_type
== FSID_MAJOR_MINOR
) {
157 /* deprecated, convert to type 3 */
158 len
= key_len(FSID_ENCODE_DEV
)/4;
159 fh
->fh_fsid_type
= FSID_ENCODE_DEV
;
160 fh
->fh_fsid
[0] = new_encode_dev(MKDEV(ntohl(fh
->fh_fsid
[0]), ntohl(fh
->fh_fsid
[1])));
161 fh
->fh_fsid
[1] = fh
->fh_fsid
[2];
166 exp
= rqst_exp_find(rqstp
, fh
->fh_fsid_type
, fh
->fh_auth
);
167 fid
= (struct fid
*)(fh
->fh_auth
+ len
);
173 if (fh
->fh_size
!= NFS_FHSIZE
)
175 /* assume old filehandle format */
176 xdev
= old_decode_dev(fh
->ofh_xdev
);
177 xino
= u32_to_ino_t(fh
->ofh_xino
);
178 mk_fsid(FSID_DEV
, tfh
, xdev
, xino
, 0, NULL
);
179 exp
= rqst_exp_find(rqstp
, FSID_DEV
, tfh
);
182 error
= nfserr_stale
;
183 if (PTR_ERR(exp
) == -ENOENT
)
187 return nfserrno(PTR_ERR(exp
));
189 if (exp
->ex_flags
& NFSEXP_NOSUBTREECHECK
) {
190 /* Elevate privileges so that the lack of 'r' or 'x'
191 * permission on some parent directory will
192 * not stop exportfs_decode_fh from being able
193 * to reconnect a directory into the dentry cache.
194 * The same problem can affect "SUBTREECHECK" exports,
195 * but as nfsd_acceptable depends on correct
196 * access control settings being in effect, we cannot
197 * fix that case easily.
199 struct cred
*new = prepare_creds();
201 return nfserrno(-ENOMEM
);
203 cap_raise_nfsd_set(new->cap_effective
,
205 put_cred(override_creds(new));
208 error
= nfsd_setuser_and_check_port(rqstp
, exp
);
214 * Look up the dentry using the NFS file handle.
216 error
= nfserr_stale
;
217 if (rqstp
->rq_vers
> 2)
218 error
= nfserr_badhandle
;
220 if (fh
->fh_version
!= 1) {
221 sfid
.i32
.ino
= fh
->ofh_ino
;
222 sfid
.i32
.gen
= fh
->ofh_generation
;
223 sfid
.i32
.parent_ino
= fh
->ofh_dirino
;
226 if (fh
->ofh_dirino
== 0)
227 fileid_type
= FILEID_INO32_GEN
;
229 fileid_type
= FILEID_INO32_GEN_PARENT
;
231 fileid_type
= fh
->fh_fileid_type
;
233 if (fileid_type
== FILEID_ROOT
)
234 dentry
= dget(exp
->ex_path
.dentry
);
236 dentry
= exportfs_decode_fh(exp
->ex_path
.mnt
, fid
,
237 data_left
, fileid_type
,
238 nfsd_acceptable
, exp
);
242 if (IS_ERR(dentry
)) {
243 if (PTR_ERR(dentry
) != -EINVAL
)
244 error
= nfserrno(PTR_ERR(dentry
));
248 if (S_ISDIR(dentry
->d_inode
->i_mode
) &&
249 (dentry
->d_flags
& DCACHE_DISCONNECTED
)) {
250 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
251 dentry
->d_parent
->d_name
.name
, dentry
->d_name
.name
);
254 fhp
->fh_dentry
= dentry
;
255 fhp
->fh_export
= exp
;
263 * fh_verify - filehandle lookup and access checking
264 * @rqstp: pointer to current rpc request
265 * @fhp: filehandle to be verified
266 * @type: expected type of object pointed to by filehandle
267 * @access: type of access needed to object
269 * Look up a dentry from the on-the-wire filehandle, check the client's
270 * access to the export, and set the current task's credentials.
272 * Regardless of success or failure of fh_verify(), fh_put() should be
273 * called on @fhp when the caller is finished with the filehandle.
275 * fh_verify() may be called multiple times on a given filehandle, for
276 * example, when processing an NFSv4 compound. The first call will look
277 * up a dentry using the on-the-wire filehandle. Subsequent calls will
278 * skip the lookup and just perform the other checks and possibly change
279 * the current task's credentials.
281 * @type specifies the type of object expected using one of the S_IF*
282 * constants defined in include/linux/stat.h. The caller may use zero
283 * to indicate that it doesn't care, or a negative integer to indicate
284 * that it expects something not of the given type.
286 * @access is formed from the NFSD_MAY_* constants defined in
287 * include/linux/nfsd/nfsd.h.
290 fh_verify(struct svc_rqst
*rqstp
, struct svc_fh
*fhp
, int type
, int access
)
292 struct svc_export
*exp
;
293 struct dentry
*dentry
;
296 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp
));
298 if (!fhp
->fh_dentry
) {
299 error
= nfsd_set_fh_dentry(rqstp
, fhp
);
303 dentry
= fhp
->fh_dentry
;
304 exp
= fhp
->fh_export
;
306 * We still have to do all these permission checks, even when
307 * fh_dentry is already set:
308 * - fh_verify may be called multiple times with different
309 * "access" arguments (e.g. nfsd_proc_create calls
310 * fh_verify(...,NFSD_MAY_EXEC) first, then later (in
311 * nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
312 * - in the NFSv4 case, the filehandle may have been filled
313 * in by fh_compose, and given a dentry, but further
314 * compound operations performed with that filehandle
315 * still need permissions checks. In the worst case, a
316 * mountpoint crossing may have changed the export
317 * options, and we may now need to use a different uid
318 * (for example, if different id-squashing options are in
319 * effect on the new filesystem).
321 error
= check_pseudo_root(rqstp
, dentry
, exp
);
325 error
= nfsd_setuser_and_check_port(rqstp
, exp
);
329 error
= nfsd_mode_check(rqstp
, dentry
->d_inode
->i_mode
, type
);
334 * pseudoflavor restrictions are not enforced on NLM,
335 * which clients virtually always use auth_sys for,
336 * even while using RPCSEC_GSS for NFS.
338 if (access
& NFSD_MAY_LOCK
|| access
& NFSD_MAY_BYPASS_GSS
)
339 goto skip_pseudoflavor_check
;
341 * Clients may expect to be able to use auth_sys during mount,
342 * even if they use gss for everything else; see section 2.3.2
345 if (access
& NFSD_MAY_BYPASS_GSS_ON_ROOT
346 && exp
->ex_path
.dentry
== dentry
)
347 goto skip_pseudoflavor_check
;
349 error
= check_nfsd_access(exp
, rqstp
);
353 skip_pseudoflavor_check
:
354 /* Finally, check access permissions. */
355 error
= nfsd_permission(rqstp
, exp
, dentry
, access
);
358 dprintk("fh_verify: %s/%s permission failure, "
359 "acc=%x, error=%d\n",
360 dentry
->d_parent
->d_name
.name
,
362 access
, ntohl(error
));
365 if (error
== nfserr_stale
)
366 nfsdstats
.fh_stale
++;
372 * Compose a file handle for an NFS reply.
374 * Note that when first composed, the dentry may not yet have
375 * an inode. In this case a call to fh_update should be made
376 * before the fh goes out on the wire ...
378 static void _fh_update(struct svc_fh
*fhp
, struct svc_export
*exp
,
379 struct dentry
*dentry
)
381 if (dentry
!= exp
->ex_path
.dentry
) {
382 struct fid
*fid
= (struct fid
*)
383 (fhp
->fh_handle
.fh_auth
+ fhp
->fh_handle
.fh_size
/4 - 1);
384 int maxsize
= (fhp
->fh_maxsize
- fhp
->fh_handle
.fh_size
)/4;
385 int subtreecheck
= !(exp
->ex_flags
& NFSEXP_NOSUBTREECHECK
);
387 fhp
->fh_handle
.fh_fileid_type
=
388 exportfs_encode_fh(dentry
, fid
, &maxsize
, subtreecheck
);
389 fhp
->fh_handle
.fh_size
+= maxsize
* 4;
391 fhp
->fh_handle
.fh_fileid_type
= FILEID_ROOT
;
396 * for composing old style file handles
398 static inline void _fh_update_old(struct dentry
*dentry
,
399 struct svc_export
*exp
,
402 fh
->ofh_ino
= ino_t_to_u32(dentry
->d_inode
->i_ino
);
403 fh
->ofh_generation
= dentry
->d_inode
->i_generation
;
404 if (S_ISDIR(dentry
->d_inode
->i_mode
) ||
405 (exp
->ex_flags
& NFSEXP_NOSUBTREECHECK
))
409 static bool is_root_export(struct svc_export
*exp
)
411 return exp
->ex_path
.dentry
== exp
->ex_path
.dentry
->d_sb
->s_root
;
414 static struct super_block
*exp_sb(struct svc_export
*exp
)
416 return exp
->ex_path
.dentry
->d_inode
->i_sb
;
419 static bool fsid_type_ok_for_exp(u8 fsid_type
, struct svc_export
*exp
)
423 if (!old_valid_dev(exp_sb(exp
)->s_dev
))
426 case FSID_MAJOR_MINOR
:
427 case FSID_ENCODE_DEV
:
428 return exp_sb(exp
)->s_type
->fs_flags
& FS_REQUIRES_DEV
;
430 return exp
->ex_flags
& NFSEXP_FSID
;
433 if (!is_root_export(exp
))
436 case FSID_UUID4_INUM
:
437 case FSID_UUID16_INUM
:
438 return exp
->ex_uuid
!= NULL
;
444 static void set_version_and_fsid_type(struct svc_fh
*fhp
, struct svc_export
*exp
, struct svc_fh
*ref_fh
)
450 if (ref_fh
&& ref_fh
->fh_export
== exp
) {
451 version
= ref_fh
->fh_handle
.fh_version
;
452 fsid_type
= ref_fh
->fh_handle
.fh_fsid_type
;
458 fsid_type
= FSID_DEV
;
467 * As the fsid -> filesystem mapping was guided by
468 * user-space, there is no guarantee that the filesystem
469 * actually supports that fsid type. If it doesn't we
470 * loop around again without ref_fh set.
472 if (!fsid_type_ok_for_exp(fsid_type
, exp
))
474 } else if (exp
->ex_flags
& NFSEXP_FSID
) {
475 fsid_type
= FSID_NUM
;
476 } else if (exp
->ex_uuid
) {
477 if (fhp
->fh_maxsize
>= 64) {
478 if (is_root_export(exp
))
479 fsid_type
= FSID_UUID16
;
481 fsid_type
= FSID_UUID16_INUM
;
483 if (is_root_export(exp
))
484 fsid_type
= FSID_UUID8
;
486 fsid_type
= FSID_UUID4_INUM
;
488 } else if (!old_valid_dev(exp_sb(exp
)->s_dev
))
489 /* for newer device numbers, we must use a newer fsid format */
490 fsid_type
= FSID_ENCODE_DEV
;
492 fsid_type
= FSID_DEV
;
493 fhp
->fh_handle
.fh_version
= version
;
495 fhp
->fh_handle
.fh_fsid_type
= fsid_type
;
499 fh_compose(struct svc_fh
*fhp
, struct svc_export
*exp
, struct dentry
*dentry
,
500 struct svc_fh
*ref_fh
)
502 /* ref_fh is a reference file handle.
503 * if it is non-null and for the same filesystem, then we should compose
504 * a filehandle which is of the same version, where possible.
505 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
506 * Then create a 32byte filehandle using nfs_fhbase_old
510 struct inode
* inode
= dentry
->d_inode
;
511 struct dentry
*parent
= dentry
->d_parent
;
513 dev_t ex_dev
= exp_sb(exp
)->s_dev
;
515 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
516 MAJOR(ex_dev
), MINOR(ex_dev
),
517 (long) exp
->ex_path
.dentry
->d_inode
->i_ino
,
518 parent
->d_name
.name
, dentry
->d_name
.name
,
519 (inode
? inode
->i_ino
: 0));
521 /* Choose filehandle version and fsid type based on
522 * the reference filehandle (if it is in the same export)
523 * or the export options.
525 set_version_and_fsid_type(fhp
, exp
, ref_fh
);
530 if (fhp
->fh_locked
|| fhp
->fh_dentry
) {
531 printk(KERN_ERR
"fh_compose: fh %s/%s not initialized!\n",
532 parent
->d_name
.name
, dentry
->d_name
.name
);
534 if (fhp
->fh_maxsize
< NFS_FHSIZE
)
535 printk(KERN_ERR
"fh_compose: called with maxsize %d! %s/%s\n",
537 parent
->d_name
.name
, dentry
->d_name
.name
);
539 fhp
->fh_dentry
= dget(dentry
); /* our internal copy */
540 fhp
->fh_export
= exp
;
543 if (fhp
->fh_handle
.fh_version
== 0xca) {
544 /* old style filehandle please */
545 memset(&fhp
->fh_handle
.fh_base
, 0, NFS_FHSIZE
);
546 fhp
->fh_handle
.fh_size
= NFS_FHSIZE
;
547 fhp
->fh_handle
.ofh_dcookie
= 0xfeebbaca;
548 fhp
->fh_handle
.ofh_dev
= old_encode_dev(ex_dev
);
549 fhp
->fh_handle
.ofh_xdev
= fhp
->fh_handle
.ofh_dev
;
550 fhp
->fh_handle
.ofh_xino
=
551 ino_t_to_u32(exp
->ex_path
.dentry
->d_inode
->i_ino
);
552 fhp
->fh_handle
.ofh_dirino
= ino_t_to_u32(parent_ino(dentry
));
554 _fh_update_old(dentry
, exp
, &fhp
->fh_handle
);
557 fhp
->fh_handle
.fh_auth_type
= 0;
558 datap
= fhp
->fh_handle
.fh_auth
+0;
559 mk_fsid(fhp
->fh_handle
.fh_fsid_type
, datap
, ex_dev
,
560 exp
->ex_path
.dentry
->d_inode
->i_ino
,
561 exp
->ex_fsid
, exp
->ex_uuid
);
563 len
= key_len(fhp
->fh_handle
.fh_fsid_type
);
565 fhp
->fh_handle
.fh_size
= 4 + len
;
568 _fh_update(fhp
, exp
, dentry
);
569 if (fhp
->fh_handle
.fh_fileid_type
== 255) {
571 return nfserr_opnotsupp
;
579 * Update file handle information after changing a dentry.
580 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
583 fh_update(struct svc_fh
*fhp
)
585 struct dentry
*dentry
;
590 dentry
= fhp
->fh_dentry
;
591 if (!dentry
->d_inode
)
593 if (fhp
->fh_handle
.fh_version
!= 1) {
594 _fh_update_old(dentry
, fhp
->fh_export
, &fhp
->fh_handle
);
596 if (fhp
->fh_handle
.fh_fileid_type
!= FILEID_ROOT
)
599 _fh_update(fhp
, fhp
->fh_export
, dentry
);
600 if (fhp
->fh_handle
.fh_fileid_type
== 255)
601 return nfserr_opnotsupp
;
607 printk(KERN_ERR
"fh_update: fh not verified!\n");
610 printk(KERN_ERR
"fh_update: %s/%s still negative!\n",
611 dentry
->d_parent
->d_name
.name
, dentry
->d_name
.name
);
616 * Release a file handle.
619 fh_put(struct svc_fh
*fhp
)
621 struct dentry
* dentry
= fhp
->fh_dentry
;
622 struct svc_export
* exp
= fhp
->fh_export
;
625 fhp
->fh_dentry
= NULL
;
627 #ifdef CONFIG_NFSD_V3
628 fhp
->fh_pre_saved
= 0;
629 fhp
->fh_post_saved
= 0;
633 cache_put(&exp
->h
, &svc_export_cache
);
634 fhp
->fh_export
= NULL
;
640 * Shorthand for dprintk()'s
642 char * SVCFH_fmt(struct svc_fh
*fhp
)
644 struct knfsd_fh
*fh
= &fhp
->fh_handle
;
647 sprintf(buf
, "%d: %08x %08x %08x %08x %08x %08x",
649 fh
->fh_base
.fh_pad
[0],
650 fh
->fh_base
.fh_pad
[1],
651 fh
->fh_base
.fh_pad
[2],
652 fh
->fh_base
.fh_pad
[3],
653 fh
->fh_base
.fh_pad
[4],
654 fh
->fh_base
.fh_pad
[5]);
658 enum fsid_source
fsid_source(struct svc_fh
*fhp
)
660 if (fhp
->fh_handle
.fh_version
!= 1)
661 return FSIDSOURCE_DEV
;
662 switch(fhp
->fh_handle
.fh_fsid_type
) {
664 case FSID_ENCODE_DEV
:
665 case FSID_MAJOR_MINOR
:
666 if (exp_sb(fhp
->fh_export
)->s_type
->fs_flags
& FS_REQUIRES_DEV
)
667 return FSIDSOURCE_DEV
;
670 if (fhp
->fh_export
->ex_flags
& NFSEXP_FSID
)
671 return FSIDSOURCE_FSID
;
676 /* either a UUID type filehandle, or the filehandle doesn't
679 if (fhp
->fh_export
->ex_flags
& NFSEXP_FSID
)
680 return FSIDSOURCE_FSID
;
681 if (fhp
->fh_export
->ex_uuid
)
682 return FSIDSOURCE_UUID
;
683 return FSIDSOURCE_DEV
;