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 %pd\n", tdentry
, tdentry
);
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
, umode_t requested
)
66 if (requested
== 0) /* the caller doesn't care */
68 if (mode
== requested
)
71 * v4 has an error more specific than err_notdir which we should
72 * return in preference to err_notdir:
74 if (rqstp
->rq_vers
== 4 && mode
== S_IFLNK
)
75 return nfserr_symlink
;
76 if (requested
== S_IFDIR
)
83 static __be32
nfsd_setuser_and_check_port(struct svc_rqst
*rqstp
,
84 struct svc_export
*exp
)
86 int flags
= nfsexp_flags(rqstp
, exp
);
88 /* Check if the request originated from a secure port. */
89 if (!rqstp
->rq_secure
&& !(flags
& NFSEXP_INSECURE_PORT
)) {
90 RPC_IFDEBUG(char buf
[RPC_MAX_ADDRBUFLEN
]);
91 dprintk("nfsd: request from insecure port %s!\n",
92 svc_print_addr(rqstp
, buf
, sizeof(buf
)));
96 /* Set user creds for this exportpoint */
97 return nfserrno(nfsd_setuser(rqstp
, exp
));
100 static inline __be32
check_pseudo_root(struct svc_rqst
*rqstp
,
101 struct dentry
*dentry
, struct svc_export
*exp
)
103 if (!(exp
->ex_flags
& NFSEXP_V4ROOT
))
106 * v2/v3 clients have no need for the V4ROOT export--they use
107 * the mount protocl instead; also, further V4ROOT checks may be
108 * in v4-specific code, in which case v2/v3 clients could bypass
111 if (!nfsd_v4client(rqstp
))
114 * We're exposing only the directories and symlinks that have to be
115 * traversed on the way to real exports:
117 if (unlikely(!S_ISDIR(dentry
->d_inode
->i_mode
) &&
118 !S_ISLNK(dentry
->d_inode
->i_mode
)))
121 * A pseudoroot export gives permission to access only one
122 * single directory; the kernel has to make another upcall
123 * before granting access to anything else under it:
125 if (unlikely(dentry
!= exp
->ex_path
.dentry
))
131 * Use the given filehandle to look up the corresponding export and
132 * dentry. On success, the results are used to set fh_export and
135 static __be32
nfsd_set_fh_dentry(struct svc_rqst
*rqstp
, struct svc_fh
*fhp
)
137 struct knfsd_fh
*fh
= &fhp
->fh_handle
;
138 struct fid
*fid
= NULL
, sfid
;
139 struct svc_export
*exp
;
140 struct dentry
*dentry
;
142 int data_left
= fh
->fh_size
/4;
145 error
= nfserr_stale
;
146 if (rqstp
->rq_vers
> 2)
147 error
= nfserr_badhandle
;
148 if (rqstp
->rq_vers
== 4 && fh
->fh_size
== 0)
149 return nfserr_nofilehandle
;
151 if (fh
->fh_version
== 1) {
156 if (fh
->fh_auth_type
!= 0)
158 len
= key_len(fh
->fh_fsid_type
) / 4;
161 if (fh
->fh_fsid_type
== FSID_MAJOR_MINOR
) {
162 /* deprecated, convert to type 3 */
163 len
= key_len(FSID_ENCODE_DEV
)/4;
164 fh
->fh_fsid_type
= FSID_ENCODE_DEV
;
166 * struct knfsd_fh uses host-endian fields, which are
167 * sometimes used to hold net-endian values. This
168 * confuses sparse, so we must use __force here to
169 * keep it from complaining.
171 fh
->fh_fsid
[0] = new_encode_dev(MKDEV(ntohl((__force __be32
)fh
->fh_fsid
[0]),
172 ntohl((__force __be32
)fh
->fh_fsid
[1])));
173 fh
->fh_fsid
[1] = fh
->fh_fsid
[2];
178 exp
= rqst_exp_find(rqstp
, fh
->fh_fsid_type
, fh
->fh_fsid
);
179 fid
= (struct fid
*)(fh
->fh_fsid
+ len
);
185 if (fh
->fh_size
!= NFS_FHSIZE
)
187 /* assume old filehandle format */
188 xdev
= old_decode_dev(fh
->ofh_xdev
);
189 xino
= u32_to_ino_t(fh
->ofh_xino
);
190 mk_fsid(FSID_DEV
, tfh
, xdev
, xino
, 0, NULL
);
191 exp
= rqst_exp_find(rqstp
, FSID_DEV
, tfh
);
194 error
= nfserr_stale
;
195 if (PTR_ERR(exp
) == -ENOENT
)
199 return nfserrno(PTR_ERR(exp
));
201 if (exp
->ex_flags
& NFSEXP_NOSUBTREECHECK
) {
202 /* Elevate privileges so that the lack of 'r' or 'x'
203 * permission on some parent directory will
204 * not stop exportfs_decode_fh from being able
205 * to reconnect a directory into the dentry cache.
206 * The same problem can affect "SUBTREECHECK" exports,
207 * but as nfsd_acceptable depends on correct
208 * access control settings being in effect, we cannot
209 * fix that case easily.
211 struct cred
*new = prepare_creds();
213 return nfserrno(-ENOMEM
);
215 cap_raise_nfsd_set(new->cap_effective
,
217 put_cred(override_creds(new));
220 error
= nfsd_setuser_and_check_port(rqstp
, exp
);
226 * Look up the dentry using the NFS file handle.
228 error
= nfserr_stale
;
229 if (rqstp
->rq_vers
> 2)
230 error
= nfserr_badhandle
;
232 if (fh
->fh_version
!= 1) {
233 sfid
.i32
.ino
= fh
->ofh_ino
;
234 sfid
.i32
.gen
= fh
->ofh_generation
;
235 sfid
.i32
.parent_ino
= fh
->ofh_dirino
;
238 if (fh
->ofh_dirino
== 0)
239 fileid_type
= FILEID_INO32_GEN
;
241 fileid_type
= FILEID_INO32_GEN_PARENT
;
243 fileid_type
= fh
->fh_fileid_type
;
245 if (fileid_type
== FILEID_ROOT
)
246 dentry
= dget(exp
->ex_path
.dentry
);
248 dentry
= exportfs_decode_fh(exp
->ex_path
.mnt
, fid
,
249 data_left
, fileid_type
,
250 nfsd_acceptable
, exp
);
254 if (IS_ERR(dentry
)) {
255 if (PTR_ERR(dentry
) != -EINVAL
)
256 error
= nfserrno(PTR_ERR(dentry
));
260 if (S_ISDIR(dentry
->d_inode
->i_mode
) &&
261 (dentry
->d_flags
& DCACHE_DISCONNECTED
)) {
262 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
266 fhp
->fh_dentry
= dentry
;
267 fhp
->fh_export
= exp
;
275 * fh_verify - filehandle lookup and access checking
276 * @rqstp: pointer to current rpc request
277 * @fhp: filehandle to be verified
278 * @type: expected type of object pointed to by filehandle
279 * @access: type of access needed to object
281 * Look up a dentry from the on-the-wire filehandle, check the client's
282 * access to the export, and set the current task's credentials.
284 * Regardless of success or failure of fh_verify(), fh_put() should be
285 * called on @fhp when the caller is finished with the filehandle.
287 * fh_verify() may be called multiple times on a given filehandle, for
288 * example, when processing an NFSv4 compound. The first call will look
289 * up a dentry using the on-the-wire filehandle. Subsequent calls will
290 * skip the lookup and just perform the other checks and possibly change
291 * the current task's credentials.
293 * @type specifies the type of object expected using one of the S_IF*
294 * constants defined in include/linux/stat.h. The caller may use zero
295 * to indicate that it doesn't care, or a negative integer to indicate
296 * that it expects something not of the given type.
298 * @access is formed from the NFSD_MAY_* constants defined in
299 * include/linux/nfsd/nfsd.h.
302 fh_verify(struct svc_rqst
*rqstp
, struct svc_fh
*fhp
, umode_t type
, int access
)
304 struct svc_export
*exp
;
305 struct dentry
*dentry
;
308 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp
));
310 if (!fhp
->fh_dentry
) {
311 error
= nfsd_set_fh_dentry(rqstp
, fhp
);
315 dentry
= fhp
->fh_dentry
;
316 exp
= fhp
->fh_export
;
318 * We still have to do all these permission checks, even when
319 * fh_dentry is already set:
320 * - fh_verify may be called multiple times with different
321 * "access" arguments (e.g. nfsd_proc_create calls
322 * fh_verify(...,NFSD_MAY_EXEC) first, then later (in
323 * nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
324 * - in the NFSv4 case, the filehandle may have been filled
325 * in by fh_compose, and given a dentry, but further
326 * compound operations performed with that filehandle
327 * still need permissions checks. In the worst case, a
328 * mountpoint crossing may have changed the export
329 * options, and we may now need to use a different uid
330 * (for example, if different id-squashing options are in
331 * effect on the new filesystem).
333 error
= check_pseudo_root(rqstp
, dentry
, exp
);
337 error
= nfsd_setuser_and_check_port(rqstp
, exp
);
341 error
= nfsd_mode_check(rqstp
, dentry
->d_inode
->i_mode
, type
);
346 * pseudoflavor restrictions are not enforced on NLM,
347 * which clients virtually always use auth_sys for,
348 * even while using RPCSEC_GSS for NFS.
350 if (access
& NFSD_MAY_LOCK
|| access
& NFSD_MAY_BYPASS_GSS
)
351 goto skip_pseudoflavor_check
;
353 * Clients may expect to be able to use auth_sys during mount,
354 * even if they use gss for everything else; see section 2.3.2
357 if (access
& NFSD_MAY_BYPASS_GSS_ON_ROOT
358 && exp
->ex_path
.dentry
== dentry
)
359 goto skip_pseudoflavor_check
;
361 error
= check_nfsd_access(exp
, rqstp
);
365 skip_pseudoflavor_check
:
366 /* Finally, check access permissions. */
367 error
= nfsd_permission(rqstp
, exp
, dentry
, access
);
370 dprintk("fh_verify: %pd2 permission failure, "
371 "acc=%x, error=%d\n",
373 access
, ntohl(error
));
376 if (error
== nfserr_stale
)
377 nfsdstats
.fh_stale
++;
383 * Compose a file handle for an NFS reply.
385 * Note that when first composed, the dentry may not yet have
386 * an inode. In this case a call to fh_update should be made
387 * before the fh goes out on the wire ...
389 static void _fh_update(struct svc_fh
*fhp
, struct svc_export
*exp
,
390 struct dentry
*dentry
)
392 if (dentry
!= exp
->ex_path
.dentry
) {
393 struct fid
*fid
= (struct fid
*)
394 (fhp
->fh_handle
.fh_fsid
+ fhp
->fh_handle
.fh_size
/4 - 1);
395 int maxsize
= (fhp
->fh_maxsize
- fhp
->fh_handle
.fh_size
)/4;
396 int subtreecheck
= !(exp
->ex_flags
& NFSEXP_NOSUBTREECHECK
);
398 fhp
->fh_handle
.fh_fileid_type
=
399 exportfs_encode_fh(dentry
, fid
, &maxsize
, subtreecheck
);
400 fhp
->fh_handle
.fh_size
+= maxsize
* 4;
402 fhp
->fh_handle
.fh_fileid_type
= FILEID_ROOT
;
407 * for composing old style file handles
409 static inline void _fh_update_old(struct dentry
*dentry
,
410 struct svc_export
*exp
,
413 fh
->ofh_ino
= ino_t_to_u32(dentry
->d_inode
->i_ino
);
414 fh
->ofh_generation
= dentry
->d_inode
->i_generation
;
415 if (S_ISDIR(dentry
->d_inode
->i_mode
) ||
416 (exp
->ex_flags
& NFSEXP_NOSUBTREECHECK
))
420 static bool is_root_export(struct svc_export
*exp
)
422 return exp
->ex_path
.dentry
== exp
->ex_path
.dentry
->d_sb
->s_root
;
425 static struct super_block
*exp_sb(struct svc_export
*exp
)
427 return exp
->ex_path
.dentry
->d_inode
->i_sb
;
430 static bool fsid_type_ok_for_exp(u8 fsid_type
, struct svc_export
*exp
)
434 if (!old_valid_dev(exp_sb(exp
)->s_dev
))
437 case FSID_MAJOR_MINOR
:
438 case FSID_ENCODE_DEV
:
439 return exp_sb(exp
)->s_type
->fs_flags
& FS_REQUIRES_DEV
;
441 return exp
->ex_flags
& NFSEXP_FSID
;
444 if (!is_root_export(exp
))
447 case FSID_UUID4_INUM
:
448 case FSID_UUID16_INUM
:
449 return exp
->ex_uuid
!= NULL
;
455 static void set_version_and_fsid_type(struct svc_fh
*fhp
, struct svc_export
*exp
, struct svc_fh
*ref_fh
)
461 if (ref_fh
&& ref_fh
->fh_export
== exp
) {
462 version
= ref_fh
->fh_handle
.fh_version
;
463 fsid_type
= ref_fh
->fh_handle
.fh_fsid_type
;
469 fsid_type
= FSID_DEV
;
478 * As the fsid -> filesystem mapping was guided by
479 * user-space, there is no guarantee that the filesystem
480 * actually supports that fsid type. If it doesn't we
481 * loop around again without ref_fh set.
483 if (!fsid_type_ok_for_exp(fsid_type
, exp
))
485 } else if (exp
->ex_flags
& NFSEXP_FSID
) {
486 fsid_type
= FSID_NUM
;
487 } else if (exp
->ex_uuid
) {
488 if (fhp
->fh_maxsize
>= 64) {
489 if (is_root_export(exp
))
490 fsid_type
= FSID_UUID16
;
492 fsid_type
= FSID_UUID16_INUM
;
494 if (is_root_export(exp
))
495 fsid_type
= FSID_UUID8
;
497 fsid_type
= FSID_UUID4_INUM
;
499 } else if (!old_valid_dev(exp_sb(exp
)->s_dev
))
500 /* for newer device numbers, we must use a newer fsid format */
501 fsid_type
= FSID_ENCODE_DEV
;
503 fsid_type
= FSID_DEV
;
504 fhp
->fh_handle
.fh_version
= version
;
506 fhp
->fh_handle
.fh_fsid_type
= fsid_type
;
510 fh_compose(struct svc_fh
*fhp
, struct svc_export
*exp
, struct dentry
*dentry
,
511 struct svc_fh
*ref_fh
)
513 /* ref_fh is a reference file handle.
514 * if it is non-null and for the same filesystem, then we should compose
515 * a filehandle which is of the same version, where possible.
516 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
517 * Then create a 32byte filehandle using nfs_fhbase_old
521 struct inode
* inode
= dentry
->d_inode
;
522 dev_t ex_dev
= exp_sb(exp
)->s_dev
;
524 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)\n",
525 MAJOR(ex_dev
), MINOR(ex_dev
),
526 (long) exp
->ex_path
.dentry
->d_inode
->i_ino
,
528 (inode
? inode
->i_ino
: 0));
530 /* Choose filehandle version and fsid type based on
531 * the reference filehandle (if it is in the same export)
532 * or the export options.
534 set_version_and_fsid_type(fhp
, exp
, ref_fh
);
539 if (fhp
->fh_locked
|| fhp
->fh_dentry
) {
540 printk(KERN_ERR
"fh_compose: fh %pd2 not initialized!\n",
543 if (fhp
->fh_maxsize
< NFS_FHSIZE
)
544 printk(KERN_ERR
"fh_compose: called with maxsize %d! %pd2\n",
548 fhp
->fh_dentry
= dget(dentry
); /* our internal copy */
549 fhp
->fh_export
= exp_get(exp
);
551 if (fhp
->fh_handle
.fh_version
== 0xca) {
552 /* old style filehandle please */
553 memset(&fhp
->fh_handle
.fh_base
, 0, NFS_FHSIZE
);
554 fhp
->fh_handle
.fh_size
= NFS_FHSIZE
;
555 fhp
->fh_handle
.ofh_dcookie
= 0xfeebbaca;
556 fhp
->fh_handle
.ofh_dev
= old_encode_dev(ex_dev
);
557 fhp
->fh_handle
.ofh_xdev
= fhp
->fh_handle
.ofh_dev
;
558 fhp
->fh_handle
.ofh_xino
=
559 ino_t_to_u32(exp
->ex_path
.dentry
->d_inode
->i_ino
);
560 fhp
->fh_handle
.ofh_dirino
= ino_t_to_u32(parent_ino(dentry
));
562 _fh_update_old(dentry
, exp
, &fhp
->fh_handle
);
564 fhp
->fh_handle
.fh_size
=
565 key_len(fhp
->fh_handle
.fh_fsid_type
) + 4;
566 fhp
->fh_handle
.fh_auth_type
= 0;
568 mk_fsid(fhp
->fh_handle
.fh_fsid_type
,
569 fhp
->fh_handle
.fh_fsid
,
571 exp
->ex_path
.dentry
->d_inode
->i_ino
,
572 exp
->ex_fsid
, exp
->ex_uuid
);
575 _fh_update(fhp
, exp
, dentry
);
576 if (fhp
->fh_handle
.fh_fileid_type
== FILEID_INVALID
) {
578 return nfserr_opnotsupp
;
586 * Update file handle information after changing a dentry.
587 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
590 fh_update(struct svc_fh
*fhp
)
592 struct dentry
*dentry
;
597 dentry
= fhp
->fh_dentry
;
598 if (!dentry
->d_inode
)
600 if (fhp
->fh_handle
.fh_version
!= 1) {
601 _fh_update_old(dentry
, fhp
->fh_export
, &fhp
->fh_handle
);
603 if (fhp
->fh_handle
.fh_fileid_type
!= FILEID_ROOT
)
606 _fh_update(fhp
, fhp
->fh_export
, dentry
);
607 if (fhp
->fh_handle
.fh_fileid_type
== FILEID_INVALID
)
608 return nfserr_opnotsupp
;
612 printk(KERN_ERR
"fh_update: fh not verified!\n");
613 return nfserr_serverfault
;
615 printk(KERN_ERR
"fh_update: %pd2 still negative!\n",
617 return nfserr_serverfault
;
621 * Release a file handle.
624 fh_put(struct svc_fh
*fhp
)
626 struct dentry
* dentry
= fhp
->fh_dentry
;
627 struct svc_export
* exp
= fhp
->fh_export
;
630 fhp
->fh_dentry
= NULL
;
632 #ifdef CONFIG_NFSD_V3
633 fhp
->fh_pre_saved
= 0;
634 fhp
->fh_post_saved
= 0;
640 fhp
->fh_export
= NULL
;
646 * Shorthand for dprintk()'s
648 char * SVCFH_fmt(struct svc_fh
*fhp
)
650 struct knfsd_fh
*fh
= &fhp
->fh_handle
;
653 sprintf(buf
, "%d: %08x %08x %08x %08x %08x %08x",
655 fh
->fh_base
.fh_pad
[0],
656 fh
->fh_base
.fh_pad
[1],
657 fh
->fh_base
.fh_pad
[2],
658 fh
->fh_base
.fh_pad
[3],
659 fh
->fh_base
.fh_pad
[4],
660 fh
->fh_base
.fh_pad
[5]);
664 enum fsid_source
fsid_source(struct svc_fh
*fhp
)
666 if (fhp
->fh_handle
.fh_version
!= 1)
667 return FSIDSOURCE_DEV
;
668 switch(fhp
->fh_handle
.fh_fsid_type
) {
670 case FSID_ENCODE_DEV
:
671 case FSID_MAJOR_MINOR
:
672 if (exp_sb(fhp
->fh_export
)->s_type
->fs_flags
& FS_REQUIRES_DEV
)
673 return FSIDSOURCE_DEV
;
676 if (fhp
->fh_export
->ex_flags
& NFSEXP_FSID
)
677 return FSIDSOURCE_FSID
;
682 /* either a UUID type filehandle, or the filehandle doesn't
685 if (fhp
->fh_export
->ex_flags
& NFSEXP_FSID
)
686 return FSIDSOURCE_FSID
;
687 if (fhp
->fh_export
->ex_uuid
)
688 return FSIDSOURCE_UUID
;
689 return FSIDSOURCE_DEV
;