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));
106 static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
107 struct dentry *dentry, struct svc_export *exp)
109 if (!(exp->ex_flags & NFSEXP_V4ROOT))
112 * v2/v3 clients have no need for the V4ROOT export--they use
113 * the mount protocl instead; also, further V4ROOT checks may be
114 * in v4-specific code, in which case v2/v3 clients could bypass
117 if (!nfsd_v4client(rqstp))
120 * We're exposing only the directories and symlinks that have to be
121 * traversed on the way to real exports:
123 if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) &&
124 !S_ISLNK(dentry->d_inode->i_mode)))
127 * A pseudoroot export gives permission to access only one
128 * single directory; the kernel has to make another upcall
129 * before granting access to anything else under it:
131 if (unlikely(dentry != exp->ex_path.dentry))
137 * Use the given filehandle to look up the corresponding export and
138 * dentry. On success, the results are used to set fh_export and
141 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
143 struct knfsd_fh *fh = &fhp->fh_handle;
144 struct fid *fid = NULL, sfid;
145 struct svc_export *exp;
146 struct dentry *dentry;
148 int data_left = fh->fh_size/4;
151 error = nfserr_stale;
152 if (rqstp->rq_vers > 2)
153 error = nfserr_badhandle;
154 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
155 return nfserr_nofilehandle;
157 if (fh->fh_version == 1) {
162 if (fh->fh_auth_type != 0)
164 len = key_len(fh->fh_fsid_type) / 4;
167 if (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
168 /* deprecated, convert to type 3 */
169 len = key_len(FSID_ENCODE_DEV)/4;
170 fh->fh_fsid_type = FSID_ENCODE_DEV;
171 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
172 fh->fh_fsid[1] = fh->fh_fsid[2];
177 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
178 fid = (struct fid *)(fh->fh_auth + len);
184 if (fh->fh_size != NFS_FHSIZE)
186 /* assume old filehandle format */
187 xdev = old_decode_dev(fh->ofh_xdev);
188 xino = u32_to_ino_t(fh->ofh_xino);
189 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
190 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
193 error = nfserr_stale;
194 if (PTR_ERR(exp) == -ENOENT)
198 return nfserrno(PTR_ERR(exp));
200 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
201 /* Elevate privileges so that the lack of 'r' or 'x'
202 * permission on some parent directory will
203 * not stop exportfs_decode_fh from being able
204 * to reconnect a directory into the dentry cache.
205 * The same problem can affect "SUBTREECHECK" exports,
206 * but as nfsd_acceptable depends on correct
207 * access control settings being in effect, we cannot
208 * fix that case easily.
210 struct cred *new = prepare_creds();
212 return nfserrno(-ENOMEM);
214 cap_raise_nfsd_set(new->cap_effective,
216 put_cred(override_creds(new));
219 error = nfsd_setuser_and_check_port(rqstp, exp);
225 * Look up the dentry using the NFS file handle.
227 error = nfserr_stale;
228 if (rqstp->rq_vers > 2)
229 error = nfserr_badhandle;
231 if (fh->fh_version != 1) {
232 sfid.i32.ino = fh->ofh_ino;
233 sfid.i32.gen = fh->ofh_generation;
234 sfid.i32.parent_ino = fh->ofh_dirino;
237 if (fh->ofh_dirino == 0)
238 fileid_type = FILEID_INO32_GEN;
240 fileid_type = FILEID_INO32_GEN_PARENT;
242 fileid_type = fh->fh_fileid_type;
244 if (fileid_type == FILEID_ROOT)
245 dentry = dget(exp->ex_path.dentry);
247 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
248 data_left, fileid_type,
249 nfsd_acceptable, exp);
253 if (IS_ERR(dentry)) {
254 if (PTR_ERR(dentry) != -EINVAL)
255 error = nfserrno(PTR_ERR(dentry));
259 if (S_ISDIR(dentry->d_inode->i_mode) &&
260 (dentry->d_flags & DCACHE_DISCONNECTED)) {
261 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
262 dentry->d_parent->d_name.name, dentry->d_name.name);
265 fhp->fh_dentry = dentry;
266 fhp->fh_export = exp;
274 * fh_verify - filehandle lookup and access checking
275 * @rqstp: pointer to current rpc request
276 * @fhp: filehandle to be verified
277 * @type: expected type of object pointed to by filehandle
278 * @access: type of access needed to object
280 * Look up a dentry from the on-the-wire filehandle, check the client's
281 * access to the export, and set the current task's credentials.
283 * Regardless of success or failure of fh_verify(), fh_put() should be
284 * called on @fhp when the caller is finished with the filehandle.
286 * fh_verify() may be called multiple times on a given filehandle, for
287 * example, when processing an NFSv4 compound. The first call will look
288 * up a dentry using the on-the-wire filehandle. Subsequent calls will
289 * skip the lookup and just perform the other checks and possibly change
290 * the current task's credentials.
292 * @type specifies the type of object expected using one of the S_IF*
293 * constants defined in include/linux/stat.h. The caller may use zero
294 * to indicate that it doesn't care, or a negative integer to indicate
295 * that it expects something not of the given type.
297 * @access is formed from the NFSD_MAY_* constants defined in
298 * include/linux/nfsd/nfsd.h.
301 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
303 struct svc_export *exp;
304 struct dentry *dentry;
307 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
309 if (!fhp->fh_dentry) {
310 error = nfsd_set_fh_dentry(rqstp, fhp);
314 dentry = fhp->fh_dentry;
315 exp = fhp->fh_export;
317 * We still have to do all these permission checks, even when
318 * fh_dentry is already set:
319 * - fh_verify may be called multiple times with different
320 * "access" arguments (e.g. nfsd_proc_create calls
321 * fh_verify(...,NFSD_MAY_EXEC) first, then later (in
322 * nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
323 * - in the NFSv4 case, the filehandle may have been filled
324 * in by fh_compose, and given a dentry, but further
325 * compound operations performed with that filehandle
326 * still need permissions checks. In the worst case, a
327 * mountpoint crossing may have changed the export
328 * options, and we may now need to use a different uid
329 * (for example, if different id-squashing options are in
330 * effect on the new filesystem).
332 error = check_pseudo_root(rqstp, dentry, exp);
336 error = nfsd_setuser_and_check_port(rqstp, exp);
340 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
345 * pseudoflavor restrictions are not enforced on NLM,
346 * which clients virtually always use auth_sys for,
347 * even while using RPCSEC_GSS for NFS.
349 if (access & NFSD_MAY_LOCK)
350 goto skip_pseudoflavor_check;
352 * Clients may expect to be able to use auth_sys during mount,
353 * even if they use gss for everything else; see section 2.3.2
356 if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
357 && exp->ex_path.dentry == dentry)
358 goto skip_pseudoflavor_check;
360 error = check_nfsd_access(exp, rqstp);
364 skip_pseudoflavor_check:
365 /* Finally, check access permissions. */
366 error = nfsd_permission(rqstp, exp, dentry, access);
369 dprintk("fh_verify: %s/%s permission failure, "
370 "acc=%x, error=%d\n",
371 dentry->d_parent->d_name.name,
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_auth + 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 struct dentry *parent = dentry->d_parent;
524 dev_t ex_dev = exp_sb(exp)->s_dev;
526 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
527 MAJOR(ex_dev), MINOR(ex_dev),
528 (long) exp->ex_path.dentry->d_inode->i_ino,
529 parent->d_name.name, dentry->d_name.name,
530 (inode ? inode->i_ino : 0));
532 /* Choose filehandle version and fsid type based on
533 * the reference filehandle (if it is in the same export)
534 * or the export options.
536 set_version_and_fsid_type(fhp, exp, ref_fh);
541 if (fhp->fh_locked || fhp->fh_dentry) {
542 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
543 parent->d_name.name, dentry->d_name.name);
545 if (fhp->fh_maxsize < NFS_FHSIZE)
546 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
548 parent->d_name.name, dentry->d_name.name);
550 fhp->fh_dentry = dget(dentry); /* our internal copy */
551 fhp->fh_export = exp;
554 if (fhp->fh_handle.fh_version == 0xca) {
555 /* old style filehandle please */
556 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
557 fhp->fh_handle.fh_size = NFS_FHSIZE;
558 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
559 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev);
560 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
561 fhp->fh_handle.ofh_xino =
562 ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
563 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
565 _fh_update_old(dentry, exp, &fhp->fh_handle);
568 fhp->fh_handle.fh_auth_type = 0;
569 datap = fhp->fh_handle.fh_auth+0;
570 mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
571 exp->ex_path.dentry->d_inode->i_ino,
572 exp->ex_fsid, exp->ex_uuid);
574 len = key_len(fhp->fh_handle.fh_fsid_type);
576 fhp->fh_handle.fh_size = 4 + len;
579 _fh_update(fhp, exp, dentry);
580 if (fhp->fh_handle.fh_fileid_type == 255) {
582 return nfserr_opnotsupp;
590 * Update file handle information after changing a dentry.
591 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
594 fh_update(struct svc_fh *fhp)
596 struct dentry *dentry;
601 dentry = fhp->fh_dentry;
602 if (!dentry->d_inode)
604 if (fhp->fh_handle.fh_version != 1) {
605 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
607 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
610 _fh_update(fhp, fhp->fh_export, dentry);
611 if (fhp->fh_handle.fh_fileid_type == 255)
612 return nfserr_opnotsupp;
618 printk(KERN_ERR "fh_update: fh not verified!\n");
621 printk(KERN_ERR "fh_update: %s/%s still negative!\n",
622 dentry->d_parent->d_name.name, dentry->d_name.name);
627 * Release a file handle.
630 fh_put(struct svc_fh *fhp)
632 struct dentry * dentry = fhp->fh_dentry;
633 struct svc_export * exp = fhp->fh_export;
636 fhp->fh_dentry = NULL;
638 #ifdef CONFIG_NFSD_V3
639 fhp->fh_pre_saved = 0;
640 fhp->fh_post_saved = 0;
644 cache_put(&exp->h, &svc_export_cache);
645 fhp->fh_export = NULL;
651 * Shorthand for dprintk()'s
653 char * SVCFH_fmt(struct svc_fh *fhp)
655 struct knfsd_fh *fh = &fhp->fh_handle;
658 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
660 fh->fh_base.fh_pad[0],
661 fh->fh_base.fh_pad[1],
662 fh->fh_base.fh_pad[2],
663 fh->fh_base.fh_pad[3],
664 fh->fh_base.fh_pad[4],
665 fh->fh_base.fh_pad[5]);
669 enum fsid_source fsid_source(struct svc_fh *fhp)
671 if (fhp->fh_handle.fh_version != 1)
672 return FSIDSOURCE_DEV;
673 switch(fhp->fh_handle.fh_fsid_type) {
675 case FSID_ENCODE_DEV:
676 case FSID_MAJOR_MINOR:
677 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
678 return FSIDSOURCE_DEV;
681 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
682 return FSIDSOURCE_FSID;
687 /* either a UUID type filehandle, or the filehandle doesn't
690 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
691 return FSIDSOURCE_FSID;
692 if (fhp->fh_export->ex_uuid)
693 return FSIDSOURCE_UUID;
694 return FSIDSOURCE_DEV;