2 * linux/fs/nfsd/nfsfh.c
4 * NFS server file handle treatment.
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
12 #include <linux/slab.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>
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>
28 #define NFSDDBG_FACILITY NFSDDBG_FH
32 * our acceptability function.
33 * if NOSUBTREECHECK, accept anything
34 * if not, require that we can walk up to exp->ex_dentry
35 * doing some checks on the 'x' bits
37 static int nfsd_acceptable(void *expv, struct dentry *dentry)
39 struct svc_export *exp = expv;
41 struct dentry *tdentry;
42 struct dentry *parent;
44 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
47 tdentry = dget(dentry);
48 while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
49 /* make sure parents give x permission to user */
51 parent = dget_parent(tdentry);
52 err = inode_permission(parent->d_inode, MAY_EXEC);
60 if (tdentry != exp->ex_path.dentry)
61 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
62 rv = (tdentry == exp->ex_path.dentry);
67 /* Type check. The correct error return for type mismatches does not seem to be
68 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
69 * comment in the NFSv3 spec says this is incorrect (implementation notes for
73 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
75 /* Type can be negative when creating hardlinks - not to a dir */
76 if (type > 0 && (mode & S_IFMT) != type) {
77 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
78 return nfserr_symlink;
79 else if (type == S_IFDIR)
81 else if ((mode & S_IFMT) == S_IFDIR)
86 if (type < 0 && (mode & S_IFMT) == -type) {
87 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
88 return nfserr_symlink;
89 else if (type == -S_IFDIR)
97 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
98 struct svc_export *exp)
100 /* Check if the request originated from a secure port. */
101 if (!rqstp->rq_secure && EX_SECURE(exp)) {
102 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
104 "nfsd: request from insecure port %s!\n",
105 svc_print_addr(rqstp, buf, sizeof(buf)));
109 /* Set user creds for this exportpoint */
110 return nfserrno(nfsd_setuser(rqstp, exp));
114 * Use the given filehandle to look up the corresponding export and
115 * dentry. On success, the results are used to set fh_export and
118 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
120 struct knfsd_fh *fh = &fhp->fh_handle;
121 struct fid *fid = NULL, sfid;
122 struct svc_export *exp;
123 struct dentry *dentry;
125 int data_left = fh->fh_size/4;
128 error = nfserr_stale;
129 if (rqstp->rq_vers > 2)
130 error = nfserr_badhandle;
131 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
132 return nfserr_nofilehandle;
134 if (fh->fh_version == 1) {
139 if (fh->fh_auth_type != 0)
141 len = key_len(fh->fh_fsid_type) / 4;
144 if (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
145 /* deprecated, convert to type 3 */
146 len = key_len(FSID_ENCODE_DEV)/4;
147 fh->fh_fsid_type = FSID_ENCODE_DEV;
148 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
149 fh->fh_fsid[1] = fh->fh_fsid[2];
154 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
155 fid = (struct fid *)(fh->fh_auth + len);
161 if (fh->fh_size != NFS_FHSIZE)
163 /* assume old filehandle format */
164 xdev = old_decode_dev(fh->ofh_xdev);
165 xino = u32_to_ino_t(fh->ofh_xino);
166 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
167 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
170 error = nfserr_stale;
171 if (PTR_ERR(exp) == -ENOENT)
175 return nfserrno(PTR_ERR(exp));
177 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
178 /* Elevate privileges so that the lack of 'r' or 'x'
179 * permission on some parent directory will
180 * not stop exportfs_decode_fh from being able
181 * to reconnect a directory into the dentry cache.
182 * The same problem can affect "SUBTREECHECK" exports,
183 * but as nfsd_acceptable depends on correct
184 * access control settings being in effect, we cannot
185 * fix that case easily.
187 struct cred *new = prepare_creds();
189 return nfserrno(-ENOMEM);
191 cap_raise_nfsd_set(new->cap_effective,
193 put_cred(override_creds(new));
196 error = nfsd_setuser_and_check_port(rqstp, exp);
202 * Look up the dentry using the NFS file handle.
204 error = nfserr_stale;
205 if (rqstp->rq_vers > 2)
206 error = nfserr_badhandle;
208 if (fh->fh_version != 1) {
209 sfid.i32.ino = fh->ofh_ino;
210 sfid.i32.gen = fh->ofh_generation;
211 sfid.i32.parent_ino = fh->ofh_dirino;
214 if (fh->ofh_dirino == 0)
215 fileid_type = FILEID_INO32_GEN;
217 fileid_type = FILEID_INO32_GEN_PARENT;
219 fileid_type = fh->fh_fileid_type;
221 if (fileid_type == FILEID_ROOT)
222 dentry = dget(exp->ex_path.dentry);
224 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
225 data_left, fileid_type,
226 nfsd_acceptable, exp);
230 if (IS_ERR(dentry)) {
231 if (PTR_ERR(dentry) != -EINVAL)
232 error = nfserrno(PTR_ERR(dentry));
236 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
237 error = nfsd_setuser_and_check_port(rqstp, exp);
244 if (S_ISDIR(dentry->d_inode->i_mode) &&
245 (dentry->d_flags & DCACHE_DISCONNECTED)) {
246 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
247 dentry->d_parent->d_name.name, dentry->d_name.name);
250 fhp->fh_dentry = dentry;
251 fhp->fh_export = exp;
259 * fh_verify - filehandle lookup and access checking
260 * @rqstp: pointer to current rpc request
261 * @fhp: filehandle to be verified
262 * @type: expected type of object pointed to by filehandle
263 * @access: type of access needed to object
265 * Look up a dentry from the on-the-wire filehandle, check the client's
266 * access to the export, and set the current task's credentials.
268 * Regardless of success or failure of fh_verify(), fh_put() should be
269 * called on @fhp when the caller is finished with the filehandle.
271 * fh_verify() may be called multiple times on a given filehandle, for
272 * example, when processing an NFSv4 compound. The first call will look
273 * up a dentry using the on-the-wire filehandle. Subsequent calls will
274 * skip the lookup and just perform the other checks and possibly change
275 * the current task's credentials.
277 * @type specifies the type of object expected using one of the S_IF*
278 * constants defined in include/linux/stat.h. The caller may use zero
279 * to indicate that it doesn't care, or a negative integer to indicate
280 * that it expects something not of the given type.
282 * @access is formed from the NFSD_MAY_* constants defined in
283 * include/linux/nfsd/nfsd.h.
286 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
288 struct svc_export *exp;
289 struct dentry *dentry;
292 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
294 if (!fhp->fh_dentry) {
295 error = nfsd_set_fh_dentry(rqstp, fhp);
298 dentry = fhp->fh_dentry;
299 exp = fhp->fh_export;
302 * just rechecking permissions
303 * (e.g. nfsproc_create calls fh_verify, then nfsd_create
306 dprintk("nfsd: fh_verify - just checking\n");
307 dentry = fhp->fh_dentry;
308 exp = fhp->fh_export;
310 * Set user creds for this exportpoint; necessary even
311 * in the "just checking" case because this may be a
312 * filehandle that was created by fh_compose, and that
313 * is about to be used in another nfsv4 compound
316 error = nfsd_setuser_and_check_port(rqstp, exp);
321 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
326 * pseudoflavor restrictions are not enforced on NLM,
327 * which clients virtually always use auth_sys for,
328 * even while using RPCSEC_GSS for NFS.
330 if (access & NFSD_MAY_LOCK)
331 goto skip_pseudoflavor_check;
333 * Clients may expect to be able to use auth_sys during mount,
334 * even if they use gss for everything else; see section 2.3.2
337 if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
338 && exp->ex_path.dentry == dentry)
339 goto skip_pseudoflavor_check;
341 error = check_nfsd_access(exp, rqstp);
345 skip_pseudoflavor_check:
346 /* Finally, check access permissions. */
347 error = nfsd_permission(rqstp, exp, dentry, access);
350 dprintk("fh_verify: %s/%s permission failure, "
351 "acc=%x, error=%d\n",
352 dentry->d_parent->d_name.name,
354 access, ntohl(error));
357 if (error == nfserr_stale)
358 nfsdstats.fh_stale++;
364 * Compose a file handle for an NFS reply.
366 * Note that when first composed, the dentry may not yet have
367 * an inode. In this case a call to fh_update should be made
368 * before the fh goes out on the wire ...
370 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
371 struct dentry *dentry)
373 if (dentry != exp->ex_path.dentry) {
374 struct fid *fid = (struct fid *)
375 (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
376 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
377 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
379 fhp->fh_handle.fh_fileid_type =
380 exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
381 fhp->fh_handle.fh_size += maxsize * 4;
383 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
388 * for composing old style file handles
390 static inline void _fh_update_old(struct dentry *dentry,
391 struct svc_export *exp,
394 fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
395 fh->ofh_generation = dentry->d_inode->i_generation;
396 if (S_ISDIR(dentry->d_inode->i_mode) ||
397 (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
401 static bool is_root_export(struct svc_export *exp)
403 return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
406 static struct super_block *exp_sb(struct svc_export *exp)
408 return exp->ex_path.dentry->d_inode->i_sb;
411 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
415 if (!old_valid_dev(exp_sb(exp)->s_dev))
418 case FSID_MAJOR_MINOR:
419 case FSID_ENCODE_DEV:
420 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
422 return exp->ex_flags & NFSEXP_FSID;
425 if (!is_root_export(exp))
428 case FSID_UUID4_INUM:
429 case FSID_UUID16_INUM:
430 return exp->ex_uuid != NULL;
436 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
442 if (ref_fh && ref_fh->fh_export == exp) {
443 version = ref_fh->fh_handle.fh_version;
444 fsid_type = ref_fh->fh_handle.fh_fsid_type;
450 fsid_type = FSID_DEV;
459 * As the fsid -> filesystem mapping was guided by
460 * user-space, there is no guarantee that the filesystem
461 * actually supports that fsid type. If it doesn't we
462 * loop around again without ref_fh set.
464 if (!fsid_type_ok_for_exp(fsid_type, exp))
466 } else if (exp->ex_flags & NFSEXP_FSID) {
467 fsid_type = FSID_NUM;
468 } else if (exp->ex_uuid) {
469 if (fhp->fh_maxsize >= 64) {
470 if (is_root_export(exp))
471 fsid_type = FSID_UUID16;
473 fsid_type = FSID_UUID16_INUM;
475 if (is_root_export(exp))
476 fsid_type = FSID_UUID8;
478 fsid_type = FSID_UUID4_INUM;
480 } else if (!old_valid_dev(exp_sb(exp)->s_dev))
481 /* for newer device numbers, we must use a newer fsid format */
482 fsid_type = FSID_ENCODE_DEV;
484 fsid_type = FSID_DEV;
485 fhp->fh_handle.fh_version = version;
487 fhp->fh_handle.fh_fsid_type = fsid_type;
491 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
492 struct svc_fh *ref_fh)
494 /* ref_fh is a reference file handle.
495 * if it is non-null and for the same filesystem, then we should compose
496 * a filehandle which is of the same version, where possible.
497 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
498 * Then create a 32byte filehandle using nfs_fhbase_old
502 struct inode * inode = dentry->d_inode;
503 struct dentry *parent = dentry->d_parent;
505 dev_t ex_dev = exp_sb(exp)->s_dev;
507 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
508 MAJOR(ex_dev), MINOR(ex_dev),
509 (long) exp->ex_path.dentry->d_inode->i_ino,
510 parent->d_name.name, dentry->d_name.name,
511 (inode ? inode->i_ino : 0));
513 /* Choose filehandle version and fsid type based on
514 * the reference filehandle (if it is in the same export)
515 * or the export options.
517 set_version_and_fsid_type(fhp, exp, ref_fh);
522 if (fhp->fh_locked || fhp->fh_dentry) {
523 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
524 parent->d_name.name, dentry->d_name.name);
526 if (fhp->fh_maxsize < NFS_FHSIZE)
527 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
529 parent->d_name.name, dentry->d_name.name);
531 fhp->fh_dentry = dget(dentry); /* our internal copy */
532 fhp->fh_export = exp;
535 if (fhp->fh_handle.fh_version == 0xca) {
536 /* old style filehandle please */
537 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
538 fhp->fh_handle.fh_size = NFS_FHSIZE;
539 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
540 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev);
541 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
542 fhp->fh_handle.ofh_xino =
543 ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
544 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
546 _fh_update_old(dentry, exp, &fhp->fh_handle);
549 fhp->fh_handle.fh_auth_type = 0;
550 datap = fhp->fh_handle.fh_auth+0;
551 mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
552 exp->ex_path.dentry->d_inode->i_ino,
553 exp->ex_fsid, exp->ex_uuid);
555 len = key_len(fhp->fh_handle.fh_fsid_type);
557 fhp->fh_handle.fh_size = 4 + len;
560 _fh_update(fhp, exp, dentry);
561 if (fhp->fh_handle.fh_fileid_type == 255) {
563 return nfserr_opnotsupp;
571 * Update file handle information after changing a dentry.
572 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
575 fh_update(struct svc_fh *fhp)
577 struct dentry *dentry;
582 dentry = fhp->fh_dentry;
583 if (!dentry->d_inode)
585 if (fhp->fh_handle.fh_version != 1) {
586 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
588 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
591 _fh_update(fhp, fhp->fh_export, dentry);
592 if (fhp->fh_handle.fh_fileid_type == 255)
593 return nfserr_opnotsupp;
599 printk(KERN_ERR "fh_update: fh not verified!\n");
602 printk(KERN_ERR "fh_update: %s/%s still negative!\n",
603 dentry->d_parent->d_name.name, dentry->d_name.name);
608 * Release a file handle.
611 fh_put(struct svc_fh *fhp)
613 struct dentry * dentry = fhp->fh_dentry;
614 struct svc_export * exp = fhp->fh_export;
617 fhp->fh_dentry = NULL;
619 #ifdef CONFIG_NFSD_V3
620 fhp->fh_pre_saved = 0;
621 fhp->fh_post_saved = 0;
625 cache_put(&exp->h, &svc_export_cache);
626 fhp->fh_export = NULL;
632 * Shorthand for dprintk()'s
634 char * SVCFH_fmt(struct svc_fh *fhp)
636 struct knfsd_fh *fh = &fhp->fh_handle;
639 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
641 fh->fh_base.fh_pad[0],
642 fh->fh_base.fh_pad[1],
643 fh->fh_base.fh_pad[2],
644 fh->fh_base.fh_pad[3],
645 fh->fh_base.fh_pad[4],
646 fh->fh_base.fh_pad[5]);
650 enum fsid_source fsid_source(struct svc_fh *fhp)
652 if (fhp->fh_handle.fh_version != 1)
653 return FSIDSOURCE_DEV;
654 switch(fhp->fh_handle.fh_fsid_type) {
656 case FSID_ENCODE_DEV:
657 case FSID_MAJOR_MINOR:
658 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
659 return FSIDSOURCE_DEV;
662 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
663 return FSIDSOURCE_FSID;
668 /* either a UUID type filehandle, or the filehandle doesn't
671 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
672 return FSIDSOURCE_FSID;
673 if (fhp->fh_export->ex_uuid)
674 return FSIDSOURCE_UUID;
675 return FSIDSOURCE_DEV;