Fix gcc 4.5.1 miscompiling drivers/char/i8k.c (again)
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / nfsd / nfsfh.c
blob55c8e63af0be76d566e7723916675a0627145a12
1 /*
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
8 */
10 #include <linux/exportfs.h>
12 #include <linux/sunrpc/svcauth_gss.h>
13 #include "nfsd.h"
14 #include "vfs.h"
15 #include "auth.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;
29 int rv;
30 struct dentry *tdentry;
31 struct dentry *parent;
33 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
34 return 1;
36 tdentry = dget(dentry);
37 while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
38 /* make sure parents give x permission to user */
39 int err;
40 parent = dget_parent(tdentry);
41 err = inode_permission(parent->d_inode, MAY_EXEC);
42 if (err < 0) {
43 dput(parent);
44 break;
46 dput(tdentry);
47 tdentry = parent;
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);
52 dput(tdentry);
53 return rv;
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
59 * the write call).
61 static inline __be32
62 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
64 /* Type can be negative when creating hardlinks - not to a dir */
65 if (type > 0 && (mode & S_IFMT) != type) {
66 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
67 return nfserr_symlink;
68 else if (type == S_IFDIR)
69 return nfserr_notdir;
70 else if ((mode & S_IFMT) == S_IFDIR)
71 return nfserr_isdir;
72 else
73 return nfserr_inval;
75 if (type < 0 && (mode & S_IFMT) == -type) {
76 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
77 return nfserr_symlink;
78 else if (type == -S_IFDIR)
79 return nfserr_isdir;
80 else
81 return nfserr_notdir;
83 return 0;
86 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
87 struct svc_export *exp)
89 int flags = nfsexp_flags(rqstp, exp);
91 /* Check if the request originated from a secure port. */
92 if (!rqstp->rq_secure && !(flags & NFSEXP_INSECURE_PORT)) {
93 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
94 dprintk(KERN_WARNING
95 "nfsd: request from insecure port %s!\n",
96 svc_print_addr(rqstp, buf, sizeof(buf)));
97 return nfserr_perm;
100 /* Set user creds for this exportpoint */
101 return nfserrno(nfsd_setuser(rqstp, exp));
104 static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
105 struct dentry *dentry, struct svc_export *exp)
107 if (!(exp->ex_flags & NFSEXP_V4ROOT))
108 return nfs_ok;
110 * v2/v3 clients have no need for the V4ROOT export--they use
111 * the mount protocl instead; also, further V4ROOT checks may be
112 * in v4-specific code, in which case v2/v3 clients could bypass
113 * them.
115 if (!nfsd_v4client(rqstp))
116 return nfserr_stale;
118 * We're exposing only the directories and symlinks that have to be
119 * traversed on the way to real exports:
121 if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) &&
122 !S_ISLNK(dentry->d_inode->i_mode)))
123 return nfserr_stale;
125 * A pseudoroot export gives permission to access only one
126 * single directory; the kernel has to make another upcall
127 * before granting access to anything else under it:
129 if (unlikely(dentry != exp->ex_path.dentry))
130 return nfserr_stale;
131 return nfs_ok;
135 * Use the given filehandle to look up the corresponding export and
136 * dentry. On success, the results are used to set fh_export and
137 * fh_dentry.
139 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
141 struct knfsd_fh *fh = &fhp->fh_handle;
142 struct fid *fid = NULL, sfid;
143 struct svc_export *exp;
144 struct dentry *dentry;
145 int fileid_type;
146 int data_left = fh->fh_size/4;
147 __be32 error;
149 error = nfserr_stale;
150 if (rqstp->rq_vers > 2)
151 error = nfserr_badhandle;
152 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
153 return nfserr_nofilehandle;
155 if (fh->fh_version == 1) {
156 int len;
158 if (--data_left < 0)
159 return error;
160 if (fh->fh_auth_type != 0)
161 return error;
162 len = key_len(fh->fh_fsid_type) / 4;
163 if (len == 0)
164 return error;
165 if (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
166 /* deprecated, convert to type 3 */
167 len = key_len(FSID_ENCODE_DEV)/4;
168 fh->fh_fsid_type = FSID_ENCODE_DEV;
169 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
170 fh->fh_fsid[1] = fh->fh_fsid[2];
172 data_left -= len;
173 if (data_left < 0)
174 return error;
175 exp = rqst_exp_find(rqstp, fh->fh_fsid_type, fh->fh_auth);
176 fid = (struct fid *)(fh->fh_auth + len);
177 } else {
178 __u32 tfh[2];
179 dev_t xdev;
180 ino_t xino;
182 if (fh->fh_size != NFS_FHSIZE)
183 return error;
184 /* assume old filehandle format */
185 xdev = old_decode_dev(fh->ofh_xdev);
186 xino = u32_to_ino_t(fh->ofh_xino);
187 mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
188 exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
191 error = nfserr_stale;
192 if (PTR_ERR(exp) == -ENOENT)
193 return error;
195 if (IS_ERR(exp))
196 return nfserrno(PTR_ERR(exp));
198 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
199 /* Elevate privileges so that the lack of 'r' or 'x'
200 * permission on some parent directory will
201 * not stop exportfs_decode_fh from being able
202 * to reconnect a directory into the dentry cache.
203 * The same problem can affect "SUBTREECHECK" exports,
204 * but as nfsd_acceptable depends on correct
205 * access control settings being in effect, we cannot
206 * fix that case easily.
208 struct cred *new = prepare_creds();
209 if (!new)
210 return nfserrno(-ENOMEM);
211 new->cap_effective =
212 cap_raise_nfsd_set(new->cap_effective,
213 new->cap_permitted);
214 put_cred(override_creds(new));
215 put_cred(new);
216 } else {
217 error = nfsd_setuser_and_check_port(rqstp, exp);
218 if (error)
219 goto out;
223 * Look up the dentry using the NFS file handle.
225 error = nfserr_stale;
226 if (rqstp->rq_vers > 2)
227 error = nfserr_badhandle;
229 if (fh->fh_version != 1) {
230 sfid.i32.ino = fh->ofh_ino;
231 sfid.i32.gen = fh->ofh_generation;
232 sfid.i32.parent_ino = fh->ofh_dirino;
233 fid = &sfid;
234 data_left = 3;
235 if (fh->ofh_dirino == 0)
236 fileid_type = FILEID_INO32_GEN;
237 else
238 fileid_type = FILEID_INO32_GEN_PARENT;
239 } else
240 fileid_type = fh->fh_fileid_type;
242 if (fileid_type == FILEID_ROOT)
243 dentry = dget(exp->ex_path.dentry);
244 else {
245 dentry = exportfs_decode_fh(exp->ex_path.mnt, fid,
246 data_left, fileid_type,
247 nfsd_acceptable, exp);
249 if (dentry == NULL)
250 goto out;
251 if (IS_ERR(dentry)) {
252 if (PTR_ERR(dentry) != -EINVAL)
253 error = nfserrno(PTR_ERR(dentry));
254 goto out;
257 if (S_ISDIR(dentry->d_inode->i_mode) &&
258 (dentry->d_flags & DCACHE_DISCONNECTED)) {
259 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
260 dentry->d_parent->d_name.name, dentry->d_name.name);
263 fhp->fh_dentry = dentry;
264 fhp->fh_export = exp;
265 return 0;
266 out:
267 exp_put(exp);
268 return error;
272 * fh_verify - filehandle lookup and access checking
273 * @rqstp: pointer to current rpc request
274 * @fhp: filehandle to be verified
275 * @type: expected type of object pointed to by filehandle
276 * @access: type of access needed to object
278 * Look up a dentry from the on-the-wire filehandle, check the client's
279 * access to the export, and set the current task's credentials.
281 * Regardless of success or failure of fh_verify(), fh_put() should be
282 * called on @fhp when the caller is finished with the filehandle.
284 * fh_verify() may be called multiple times on a given filehandle, for
285 * example, when processing an NFSv4 compound. The first call will look
286 * up a dentry using the on-the-wire filehandle. Subsequent calls will
287 * skip the lookup and just perform the other checks and possibly change
288 * the current task's credentials.
290 * @type specifies the type of object expected using one of the S_IF*
291 * constants defined in include/linux/stat.h. The caller may use zero
292 * to indicate that it doesn't care, or a negative integer to indicate
293 * that it expects something not of the given type.
295 * @access is formed from the NFSD_MAY_* constants defined in
296 * include/linux/nfsd/nfsd.h.
298 __be32
299 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
301 struct svc_export *exp;
302 struct dentry *dentry;
303 __be32 error;
305 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
307 if (!fhp->fh_dentry) {
308 error = nfsd_set_fh_dentry(rqstp, fhp);
309 if (error)
310 goto out;
312 dentry = fhp->fh_dentry;
313 exp = fhp->fh_export;
315 * We still have to do all these permission checks, even when
316 * fh_dentry is already set:
317 * - fh_verify may be called multiple times with different
318 * "access" arguments (e.g. nfsd_proc_create calls
319 * fh_verify(...,NFSD_MAY_EXEC) first, then later (in
320 * nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
321 * - in the NFSv4 case, the filehandle may have been filled
322 * in by fh_compose, and given a dentry, but further
323 * compound operations performed with that filehandle
324 * still need permissions checks. In the worst case, a
325 * mountpoint crossing may have changed the export
326 * options, and we may now need to use a different uid
327 * (for example, if different id-squashing options are in
328 * effect on the new filesystem).
330 error = check_pseudo_root(rqstp, dentry, exp);
331 if (error)
332 goto out;
334 error = nfsd_setuser_and_check_port(rqstp, exp);
335 if (error)
336 goto out;
338 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
339 if (error)
340 goto out;
343 * pseudoflavor restrictions are not enforced on NLM,
344 * which clients virtually always use auth_sys for,
345 * even while using RPCSEC_GSS for NFS.
347 if (access & NFSD_MAY_LOCK)
348 goto skip_pseudoflavor_check;
350 * Clients may expect to be able to use auth_sys during mount,
351 * even if they use gss for everything else; see section 2.3.2
352 * of rfc 2623.
354 if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
355 && exp->ex_path.dentry == dentry)
356 goto skip_pseudoflavor_check;
358 error = check_nfsd_access(exp, rqstp);
359 if (error)
360 goto out;
362 skip_pseudoflavor_check:
363 /* Finally, check access permissions. */
364 error = nfsd_permission(rqstp, exp, dentry, access);
366 if (error) {
367 dprintk("fh_verify: %s/%s permission failure, "
368 "acc=%x, error=%d\n",
369 dentry->d_parent->d_name.name,
370 dentry->d_name.name,
371 access, ntohl(error));
373 out:
374 if (error == nfserr_stale)
375 nfsdstats.fh_stale++;
376 return error;
381 * Compose a file handle for an NFS reply.
383 * Note that when first composed, the dentry may not yet have
384 * an inode. In this case a call to fh_update should be made
385 * before the fh goes out on the wire ...
387 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
388 struct dentry *dentry)
390 if (dentry != exp->ex_path.dentry) {
391 struct fid *fid = (struct fid *)
392 (fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
393 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
394 int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);
396 fhp->fh_handle.fh_fileid_type =
397 exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
398 fhp->fh_handle.fh_size += maxsize * 4;
399 } else {
400 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
405 * for composing old style file handles
407 static inline void _fh_update_old(struct dentry *dentry,
408 struct svc_export *exp,
409 struct knfsd_fh *fh)
411 fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
412 fh->ofh_generation = dentry->d_inode->i_generation;
413 if (S_ISDIR(dentry->d_inode->i_mode) ||
414 (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
415 fh->ofh_dirino = 0;
418 static bool is_root_export(struct svc_export *exp)
420 return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
423 static struct super_block *exp_sb(struct svc_export *exp)
425 return exp->ex_path.dentry->d_inode->i_sb;
428 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
430 switch (fsid_type) {
431 case FSID_DEV:
432 if (!old_valid_dev(exp_sb(exp)->s_dev))
433 return 0;
434 /* FALL THROUGH */
435 case FSID_MAJOR_MINOR:
436 case FSID_ENCODE_DEV:
437 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
438 case FSID_NUM:
439 return exp->ex_flags & NFSEXP_FSID;
440 case FSID_UUID8:
441 case FSID_UUID16:
442 if (!is_root_export(exp))
443 return 0;
444 /* fall through */
445 case FSID_UUID4_INUM:
446 case FSID_UUID16_INUM:
447 return exp->ex_uuid != NULL;
449 return 1;
453 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
455 u8 version;
456 u8 fsid_type;
457 retry:
458 version = 1;
459 if (ref_fh && ref_fh->fh_export == exp) {
460 version = ref_fh->fh_handle.fh_version;
461 fsid_type = ref_fh->fh_handle.fh_fsid_type;
463 ref_fh = NULL;
465 switch (version) {
466 case 0xca:
467 fsid_type = FSID_DEV;
468 break;
469 case 1:
470 break;
471 default:
472 goto retry;
476 * As the fsid -> filesystem mapping was guided by
477 * user-space, there is no guarantee that the filesystem
478 * actually supports that fsid type. If it doesn't we
479 * loop around again without ref_fh set.
481 if (!fsid_type_ok_for_exp(fsid_type, exp))
482 goto retry;
483 } else if (exp->ex_flags & NFSEXP_FSID) {
484 fsid_type = FSID_NUM;
485 } else if (exp->ex_uuid) {
486 if (fhp->fh_maxsize >= 64) {
487 if (is_root_export(exp))
488 fsid_type = FSID_UUID16;
489 else
490 fsid_type = FSID_UUID16_INUM;
491 } else {
492 if (is_root_export(exp))
493 fsid_type = FSID_UUID8;
494 else
495 fsid_type = FSID_UUID4_INUM;
497 } else if (!old_valid_dev(exp_sb(exp)->s_dev))
498 /* for newer device numbers, we must use a newer fsid format */
499 fsid_type = FSID_ENCODE_DEV;
500 else
501 fsid_type = FSID_DEV;
502 fhp->fh_handle.fh_version = version;
503 if (version)
504 fhp->fh_handle.fh_fsid_type = fsid_type;
507 __be32
508 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
509 struct svc_fh *ref_fh)
511 /* ref_fh is a reference file handle.
512 * if it is non-null and for the same filesystem, then we should compose
513 * a filehandle which is of the same version, where possible.
514 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
515 * Then create a 32byte filehandle using nfs_fhbase_old
519 struct inode * inode = dentry->d_inode;
520 struct dentry *parent = dentry->d_parent;
521 __u32 *datap;
522 dev_t ex_dev = exp_sb(exp)->s_dev;
524 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
525 MAJOR(ex_dev), MINOR(ex_dev),
526 (long) exp->ex_path.dentry->d_inode->i_ino,
527 parent->d_name.name, dentry->d_name.name,
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);
536 if (ref_fh == fhp)
537 fh_put(ref_fh);
539 if (fhp->fh_locked || fhp->fh_dentry) {
540 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
541 parent->d_name.name, dentry->d_name.name);
543 if (fhp->fh_maxsize < NFS_FHSIZE)
544 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
545 fhp->fh_maxsize,
546 parent->d_name.name, dentry->d_name.name);
548 fhp->fh_dentry = dget(dentry); /* our internal copy */
549 fhp->fh_export = exp;
550 cache_get(&exp->h);
552 if (fhp->fh_handle.fh_version == 0xca) {
553 /* old style filehandle please */
554 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
555 fhp->fh_handle.fh_size = NFS_FHSIZE;
556 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
557 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev);
558 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
559 fhp->fh_handle.ofh_xino =
560 ino_t_to_u32(exp->ex_path.dentry->d_inode->i_ino);
561 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
562 if (inode)
563 _fh_update_old(dentry, exp, &fhp->fh_handle);
564 } else {
565 int len;
566 fhp->fh_handle.fh_auth_type = 0;
567 datap = fhp->fh_handle.fh_auth+0;
568 mk_fsid(fhp->fh_handle.fh_fsid_type, datap, ex_dev,
569 exp->ex_path.dentry->d_inode->i_ino,
570 exp->ex_fsid, exp->ex_uuid);
572 len = key_len(fhp->fh_handle.fh_fsid_type);
573 datap += len/4;
574 fhp->fh_handle.fh_size = 4 + len;
576 if (inode)
577 _fh_update(fhp, exp, dentry);
578 if (fhp->fh_handle.fh_fileid_type == 255) {
579 fh_put(fhp);
580 return nfserr_opnotsupp;
584 return 0;
588 * Update file handle information after changing a dentry.
589 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
591 __be32
592 fh_update(struct svc_fh *fhp)
594 struct dentry *dentry;
596 if (!fhp->fh_dentry)
597 goto out_bad;
599 dentry = fhp->fh_dentry;
600 if (!dentry->d_inode)
601 goto out_negative;
602 if (fhp->fh_handle.fh_version != 1) {
603 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
604 } else {
605 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
606 goto out;
608 _fh_update(fhp, fhp->fh_export, dentry);
609 if (fhp->fh_handle.fh_fileid_type == 255)
610 return nfserr_opnotsupp;
612 out:
613 return 0;
615 out_bad:
616 printk(KERN_ERR "fh_update: fh not verified!\n");
617 goto out;
618 out_negative:
619 printk(KERN_ERR "fh_update: %s/%s still negative!\n",
620 dentry->d_parent->d_name.name, dentry->d_name.name);
621 goto out;
625 * Release a file handle.
627 void
628 fh_put(struct svc_fh *fhp)
630 struct dentry * dentry = fhp->fh_dentry;
631 struct svc_export * exp = fhp->fh_export;
632 if (dentry) {
633 fh_unlock(fhp);
634 fhp->fh_dentry = NULL;
635 dput(dentry);
636 #ifdef CONFIG_NFSD_V3
637 fhp->fh_pre_saved = 0;
638 fhp->fh_post_saved = 0;
639 #endif
641 if (exp) {
642 cache_put(&exp->h, &svc_export_cache);
643 fhp->fh_export = NULL;
645 return;
649 * Shorthand for dprintk()'s
651 char * SVCFH_fmt(struct svc_fh *fhp)
653 struct knfsd_fh *fh = &fhp->fh_handle;
655 static char buf[80];
656 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
657 fh->fh_size,
658 fh->fh_base.fh_pad[0],
659 fh->fh_base.fh_pad[1],
660 fh->fh_base.fh_pad[2],
661 fh->fh_base.fh_pad[3],
662 fh->fh_base.fh_pad[4],
663 fh->fh_base.fh_pad[5]);
664 return buf;
667 enum fsid_source fsid_source(struct svc_fh *fhp)
669 if (fhp->fh_handle.fh_version != 1)
670 return FSIDSOURCE_DEV;
671 switch(fhp->fh_handle.fh_fsid_type) {
672 case FSID_DEV:
673 case FSID_ENCODE_DEV:
674 case FSID_MAJOR_MINOR:
675 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
676 return FSIDSOURCE_DEV;
677 break;
678 case FSID_NUM:
679 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
680 return FSIDSOURCE_FSID;
681 break;
682 default:
683 break;
685 /* either a UUID type filehandle, or the filehandle doesn't
686 * match the export.
688 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
689 return FSIDSOURCE_FSID;
690 if (fhp->fh_export->ex_uuid)
691 return FSIDSOURCE_UUID;
692 return FSIDSOURCE_DEV;