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/exportfs.h>
14 #include <linux/sunrpc/svcauth_gss.h>
19 #define NFSDDBG_FACILITY NFSDDBG_FH
23 * our acceptability function.
24 * if NOSUBTREECHECK, accept anything
25 * if not, require that we can walk up to exp->ex_dentry
26 * doing some checks on the 'x' bits
28 static int nfsd_acceptable(void *expv, struct dentry *dentry)
30 struct svc_export *exp = expv;
32 struct dentry *tdentry;
33 struct dentry *parent;
35 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
38 tdentry = dget(dentry);
39 while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
40 /* make sure parents give x permission to user */
42 parent = dget_parent(tdentry);
43 err = inode_permission(parent->d_inode, MAY_EXEC);
51 if (tdentry != exp->ex_path.dentry)
52 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
53 rv = (tdentry == exp->ex_path.dentry);
58 /* Type check. The correct error return for type mismatches does not seem to be
59 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
60 * comment in the NFSv3 spec says this is incorrect (implementation notes for
64 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
66 /* Type can be negative when creating hardlinks - not to a dir */
67 if (type > 0 && (mode & S_IFMT) != type) {
68 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
69 return nfserr_symlink;
70 else if (type == S_IFDIR)
72 else if ((mode & S_IFMT) == S_IFDIR)
77 if (type < 0 && (mode & S_IFMT) == -type) {
78 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
79 return nfserr_symlink;
80 else if (type == -S_IFDIR)
88 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
89 struct svc_export *exp)
91 int flags = nfsexp_flags(rqstp, exp);
93 /* Check if the request originated from a secure port. */
94 if (!rqstp->rq_secure && (flags & NFSEXP_INSECURE_PORT)) {
95 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
97 "nfsd: request from insecure port %s!\n",
98 svc_print_addr(rqstp, buf, sizeof(buf)));
102 /* Set user creds for this exportpoint */
103 return nfserrno(nfsd_setuser(rqstp, exp));
107 * Use the given filehandle to look up the corresponding export and
108 * dentry. On success, the results are used to set fh_export and
111 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
113 struct knfsd_fh *fh = &fhp->fh_handle;
114 struct fid *fid = NULL, sfid;
115 struct svc_export *exp;
116 struct dentry *dentry;
118 int data_left = fh->fh_size/4;
121 error = nfserr_stale;
122 if (rqstp->rq_vers > 2)
123 error = nfserr_badhandle;
124 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
125 return nfserr_nofilehandle;
127 if (fh->fh_version == 1) {
132 if (fh->fh_auth_type != 0)
134 len = key_len(fh->fh_fsid_type) / 4;
137 if (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
138 /* deprecated, convert to type 3 */
139 len = key_len(FSID_ENCODE_DEV)/4;
140 fh->fh_fsid_type = FSID_ENCODE_DEV;
141 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
142 fh->fh_fsid[1] = fh->fh_fsid[2];
147 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
148 fid = (struct fid *)(fh->fh_auth + len);
154 if (fh->fh_size != NFS_FHSIZE)
156 /* assume old filehandle format */
157 xdev = old_decode_dev(fh->ofh_xdev);
158 xino = u32_to_ino_t(fh->ofh_xino);
159 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
160 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
163 error = nfserr_stale;
164 if (PTR_ERR(exp) == -ENOENT)
168 return nfserrno(PTR_ERR(exp));
170 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
171 /* Elevate privileges so that the lack of 'r' or 'x'
172 * permission on some parent directory will
173 * not stop exportfs_decode_fh from being able
174 * to reconnect a directory into the dentry cache.
175 * The same problem can affect "SUBTREECHECK" exports,
176 * but as nfsd_acceptable depends on correct
177 * access control settings being in effect, we cannot
178 * fix that case easily.
180 struct cred *new = prepare_creds();
182 return nfserrno(-ENOMEM);
184 cap_raise_nfsd_set(new->cap_effective,
186 put_cred(override_creds(new));
189 error = nfsd_setuser_and_check_port(rqstp, exp);
195 * Look up the dentry using the NFS file handle.
197 error = nfserr_stale;
198 if (rqstp->rq_vers > 2)
199 error = nfserr_badhandle;
201 if (fh->fh_version != 1) {
202 sfid.i32.ino = fh->ofh_ino;
203 sfid.i32.gen = fh->ofh_generation;
204 sfid.i32.parent_ino = fh->ofh_dirino;
207 if (fh->ofh_dirino == 0)
208 fileid_type = FILEID_INO32_GEN;
210 fileid_type = FILEID_INO32_GEN_PARENT;
212 fileid_type = fh->fh_fileid_type;
214 if (fileid_type == FILEID_ROOT)
215 dentry = dget(exp->ex_path.dentry);
217 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
218 data_left, fileid_type,
219 nfsd_acceptable, exp);
223 if (IS_ERR(dentry)) {
224 if (PTR_ERR(dentry) != -EINVAL)
225 error = nfserrno(PTR_ERR(dentry));
229 if (S_ISDIR(dentry->d_inode->i_mode) &&
230 (dentry->d_flags & DCACHE_DISCONNECTED)) {
231 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
232 dentry->d_parent->d_name.name, dentry->d_name.name);
235 fhp->fh_dentry = dentry;
236 fhp->fh_export = exp;
244 * fh_verify - filehandle lookup and access checking
245 * @rqstp: pointer to current rpc request
246 * @fhp: filehandle to be verified
247 * @type: expected type of object pointed to by filehandle
248 * @access: type of access needed to object
250 * Look up a dentry from the on-the-wire filehandle, check the client's
251 * access to the export, and set the current task's credentials.
253 * Regardless of success or failure of fh_verify(), fh_put() should be
254 * called on @fhp when the caller is finished with the filehandle.
256 * fh_verify() may be called multiple times on a given filehandle, for
257 * example, when processing an NFSv4 compound. The first call will look
258 * up a dentry using the on-the-wire filehandle. Subsequent calls will
259 * skip the lookup and just perform the other checks and possibly change
260 * the current task's credentials.
262 * @type specifies the type of object expected using one of the S_IF*
263 * constants defined in include/linux/stat.h. The caller may use zero
264 * to indicate that it doesn't care, or a negative integer to indicate
265 * that it expects something not of the given type.
267 * @access is formed from the NFSD_MAY_* constants defined in
268 * include/linux/nfsd/nfsd.h.
271 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
273 struct svc_export *exp;
274 struct dentry *dentry;
277 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
279 if (!fhp->fh_dentry) {
280 error = nfsd_set_fh_dentry(rqstp, fhp);
284 dentry = fhp->fh_dentry;
285 exp = fhp->fh_export;
287 * We still have to do all these permission checks, even when
288 * fh_dentry is already set:
289 * - fh_verify may be called multiple times with different
290 * "access" arguments (e.g. nfsd_proc_create calls
291 * fh_verify(...,NFSD_MAY_EXEC) first, then later (in
292 * nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
293 * - in the NFSv4 case, the filehandle may have been filled
294 * in by fh_compose, and given a dentry, but further
295 * compound operations performed with that filehandle
296 * still need permissions checks. In the worst case, a
297 * mountpoint crossing may have changed the export
298 * options, and we may now need to use a different uid
299 * (for example, if different id-squashing options are in
300 * effect on the new filesystem).
302 error = nfsd_setuser_and_check_port(rqstp, exp);
306 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
311 * pseudoflavor restrictions are not enforced on NLM,
312 * which clients virtually always use auth_sys for,
313 * even while using RPCSEC_GSS for NFS.
315 if (access & NFSD_MAY_LOCK)
316 goto skip_pseudoflavor_check;
318 * Clients may expect to be able to use auth_sys during mount,
319 * even if they use gss for everything else; see section 2.3.2
322 if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
323 && exp->ex_path.dentry == dentry)
324 goto skip_pseudoflavor_check;
326 error = check_nfsd_access(exp, rqstp);
330 skip_pseudoflavor_check:
331 /* Finally, check access permissions. */
332 error = nfsd_permission(rqstp, exp, dentry, access);
335 dprintk("fh_verify: %s/%s permission failure, "
336 "acc=%x, error=%d\n",
337 dentry->d_parent->d_name.name,
339 access, ntohl(error));
342 if (error == nfserr_stale)
343 nfsdstats.fh_stale++;
349 * Compose a file handle for an NFS reply.
351 * Note that when first composed, the dentry may not yet have
352 * an inode. In this case a call to fh_update should be made
353 * before the fh goes out on the wire ...
355 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
356 struct dentry *dentry)
358 if (dentry != exp->ex_path.dentry) {
359 struct fid *fid = (struct fid *)
360 (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
361 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
362 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
364 fhp->fh_handle.fh_fileid_type =
365 exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
366 fhp->fh_handle.fh_size += maxsize * 4;
368 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
373 * for composing old style file handles
375 static inline void _fh_update_old(struct dentry *dentry,
376 struct svc_export *exp,
379 fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
380 fh->ofh_generation = dentry->d_inode->i_generation;
381 if (S_ISDIR(dentry->d_inode->i_mode) ||
382 (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
386 static bool is_root_export(struct svc_export *exp)
388 return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
391 static struct super_block *exp_sb(struct svc_export *exp)
393 return exp->ex_path.dentry->d_inode->i_sb;
396 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
400 if (!old_valid_dev(exp_sb(exp)->s_dev))
403 case FSID_MAJOR_MINOR:
404 case FSID_ENCODE_DEV:
405 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
407 return exp->ex_flags & NFSEXP_FSID;
410 if (!is_root_export(exp))
413 case FSID_UUID4_INUM:
414 case FSID_UUID16_INUM:
415 return exp->ex_uuid != NULL;
421 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
427 if (ref_fh && ref_fh->fh_export == exp) {
428 version = ref_fh->fh_handle.fh_version;
429 fsid_type = ref_fh->fh_handle.fh_fsid_type;
435 fsid_type = FSID_DEV;
444 * As the fsid -> filesystem mapping was guided by
445 * user-space, there is no guarantee that the filesystem
446 * actually supports that fsid type. If it doesn't we
447 * loop around again without ref_fh set.
449 if (!fsid_type_ok_for_exp(fsid_type, exp))
451 } else if (exp->ex_flags & NFSEXP_FSID) {
452 fsid_type = FSID_NUM;
453 } else if (exp->ex_uuid) {
454 if (fhp->fh_maxsize >= 64) {
455 if (is_root_export(exp))
456 fsid_type = FSID_UUID16;
458 fsid_type = FSID_UUID16_INUM;
460 if (is_root_export(exp))
461 fsid_type = FSID_UUID8;
463 fsid_type = FSID_UUID4_INUM;
465 } else if (!old_valid_dev(exp_sb(exp)->s_dev))
466 /* for newer device numbers, we must use a newer fsid format */
467 fsid_type = FSID_ENCODE_DEV;
469 fsid_type = FSID_DEV;
470 fhp->fh_handle.fh_version = version;
472 fhp->fh_handle.fh_fsid_type = fsid_type;
476 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
477 struct svc_fh *ref_fh)
479 /* ref_fh is a reference file handle.
480 * if it is non-null and for the same filesystem, then we should compose
481 * a filehandle which is of the same version, where possible.
482 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
483 * Then create a 32byte filehandle using nfs_fhbase_old
487 struct inode * inode = dentry->d_inode;
488 struct dentry *parent = dentry->d_parent;
490 dev_t ex_dev = exp_sb(exp)->s_dev;
492 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
493 MAJOR(ex_dev), MINOR(ex_dev),
494 (long) exp->ex_path.dentry->d_inode->i_ino,
495 parent->d_name.name, dentry->d_name.name,
496 (inode ? inode->i_ino : 0));
498 /* Choose filehandle version and fsid type based on
499 * the reference filehandle (if it is in the same export)
500 * or the export options.
502 set_version_and_fsid_type(fhp, exp, ref_fh);
507 if (fhp->fh_locked || fhp->fh_dentry) {
508 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
509 parent->d_name.name, dentry->d_name.name);
511 if (fhp->fh_maxsize < NFS_FHSIZE)
512 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
514 parent->d_name.name, dentry->d_name.name);
516 fhp->fh_dentry = dget(dentry); /* our internal copy */
517 fhp->fh_export = exp;
520 if (fhp->fh_handle.fh_version == 0xca) {
521 /* old style filehandle please */
522 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
523 fhp->fh_handle.fh_size = NFS_FHSIZE;
524 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
525 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev);
526 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
527 fhp->fh_handle.ofh_xino =
528 ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
529 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
531 _fh_update_old(dentry, exp, &fhp->fh_handle);
534 fhp->fh_handle.fh_auth_type = 0;
535 datap = fhp->fh_handle.fh_auth+0;
536 mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
537 exp->ex_path.dentry->d_inode->i_ino,
538 exp->ex_fsid, exp->ex_uuid);
540 len = key_len(fhp->fh_handle.fh_fsid_type);
542 fhp->fh_handle.fh_size = 4 + len;
545 _fh_update(fhp, exp, dentry);
546 if (fhp->fh_handle.fh_fileid_type == 255) {
548 return nfserr_opnotsupp;
556 * Update file handle information after changing a dentry.
557 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
560 fh_update(struct svc_fh *fhp)
562 struct dentry *dentry;
567 dentry = fhp->fh_dentry;
568 if (!dentry->d_inode)
570 if (fhp->fh_handle.fh_version != 1) {
571 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
573 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
576 _fh_update(fhp, fhp->fh_export, dentry);
577 if (fhp->fh_handle.fh_fileid_type == 255)
578 return nfserr_opnotsupp;
584 printk(KERN_ERR "fh_update: fh not verified!\n");
587 printk(KERN_ERR "fh_update: %s/%s still negative!\n",
588 dentry->d_parent->d_name.name, dentry->d_name.name);
593 * Release a file handle.
596 fh_put(struct svc_fh *fhp)
598 struct dentry * dentry = fhp->fh_dentry;
599 struct svc_export * exp = fhp->fh_export;
602 fhp->fh_dentry = NULL;
604 #ifdef CONFIG_NFSD_V3
605 fhp->fh_pre_saved = 0;
606 fhp->fh_post_saved = 0;
610 cache_put(&exp->h, &svc_export_cache);
611 fhp->fh_export = NULL;
617 * Shorthand for dprintk()'s
619 char * SVCFH_fmt(struct svc_fh *fhp)
621 struct knfsd_fh *fh = &fhp->fh_handle;
624 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
626 fh->fh_base.fh_pad[0],
627 fh->fh_base.fh_pad[1],
628 fh->fh_base.fh_pad[2],
629 fh->fh_base.fh_pad[3],
630 fh->fh_base.fh_pad[4],
631 fh->fh_base.fh_pad[5]);
635 enum fsid_source fsid_source(struct svc_fh *fhp)
637 if (fhp->fh_handle.fh_version != 1)
638 return FSIDSOURCE_DEV;
639 switch(fhp->fh_handle.fh_fsid_type) {
641 case FSID_ENCODE_DEV:
642 case FSID_MAJOR_MINOR:
643 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
644 return FSIDSOURCE_DEV;
647 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
648 return FSIDSOURCE_FSID;
653 /* either a UUID type filehandle, or the filehandle doesn't
656 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
657 return FSIDSOURCE_FSID;
658 if (fhp->fh_export->ex_uuid)
659 return FSIDSOURCE_UUID;
660 return FSIDSOURCE_DEV;