1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * NFS server file handle treatment.
4 *
5 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
6 * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
7 * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
8 * ... and again Southern-Winter 2001 to support export_operations
9 */
10
11 #include <linux/exportfs.h>
12
13 #include <linux/sunrpc/svcauth_gss.h>
14 #include "nfsd.h"
15 #include "vfs.h"
16 #include "auth.h"
17 #include "trace.h"
18
19 #define NFSDDBG_FACILITY NFSDDBG_FH
20
21
22 /*
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
27 */
nfsd_acceptable(void * expv,struct dentry * dentry)28 static int nfsd_acceptable(void *expv, struct dentry *dentry)
29 {
30 struct svc_export *exp = expv;
31 int rv;
32 struct dentry *tdentry;
33 struct dentry *parent;
34
35 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
36 return 1;
37
38 tdentry = dget(dentry);
39 while (tdentry != exp->ex_path.dentry && !IS_ROOT(tdentry)) {
40 /* make sure parents give x permission to user */
41 int err;
42 parent = dget_parent(tdentry);
43 err = inode_permission(&nop_mnt_idmap,
44 d_inode(parent), MAY_EXEC);
45 if (err < 0) {
46 dput(parent);
47 break;
48 }
49 dput(tdentry);
50 tdentry = parent;
51 }
52 if (tdentry != exp->ex_path.dentry)
53 dprintk("nfsd_acceptable failed at %p %pd\n", tdentry, tdentry);
54 rv = (tdentry == exp->ex_path.dentry);
55 dput(tdentry);
56 return rv;
57 }
58
59 /* Type check. The correct error return for type mismatches does not seem to be
60 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
61 * comment in the NFSv3 spec says this is incorrect (implementation notes for
62 * the write call).
63 */
64 static inline __be32
nfsd_mode_check(struct dentry * dentry,umode_t requested)65 nfsd_mode_check(struct dentry *dentry, umode_t requested)
66 {
67 umode_t mode = d_inode(dentry)->i_mode & S_IFMT;
68
69 if (requested == 0) /* the caller doesn't care */
70 return nfs_ok;
71 if (mode == requested) {
72 if (mode == S_IFDIR && !d_can_lookup(dentry)) {
73 WARN_ON_ONCE(1);
74 return nfserr_notdir;
75 }
76 return nfs_ok;
77 }
78 if (mode == S_IFLNK) {
79 if (requested == S_IFDIR)
80 return nfserr_symlink_not_dir;
81 return nfserr_symlink;
82 }
83 if (requested == S_IFDIR)
84 return nfserr_notdir;
85 if (mode == S_IFDIR)
86 return nfserr_isdir;
87 return nfserr_wrong_type;
88 }
89
nfsd_originating_port_ok(struct svc_rqst * rqstp,struct svc_cred * cred,struct svc_export * exp)90 static bool nfsd_originating_port_ok(struct svc_rqst *rqstp,
91 struct svc_cred *cred,
92 struct svc_export *exp)
93 {
94 if (nfsexp_flags(cred, exp) & NFSEXP_INSECURE_PORT)
95 return true;
96 /* We don't require gss requests to use low ports: */
97 if (cred->cr_flavor >= RPC_AUTH_GSS)
98 return true;
99 return test_bit(RQ_SECURE, &rqstp->rq_flags);
100 }
101
nfsd_setuser_and_check_port(struct svc_rqst * rqstp,struct svc_cred * cred,struct svc_export * exp)102 static __be32 nfsd_setuser_and_check_port(struct svc_rqst *rqstp,
103 struct svc_cred *cred,
104 struct svc_export *exp)
105 {
106 /* Check if the request originated from a secure port. */
107 if (rqstp && !nfsd_originating_port_ok(rqstp, cred, exp)) {
108 RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
109 dprintk("nfsd: request from insecure port %s!\n",
110 svc_print_addr(rqstp, buf, sizeof(buf)));
111 return nfserr_perm;
112 }
113
114 /* Set user creds for this exportpoint */
115 return nfserrno(nfsd_setuser(cred, exp));
116 }
117
check_pseudo_root(struct dentry * dentry,struct svc_export * exp)118 static inline __be32 check_pseudo_root(struct dentry *dentry,
119 struct svc_export *exp)
120 {
121 if (!(exp->ex_flags & NFSEXP_V4ROOT))
122 return nfs_ok;
123 /*
124 * We're exposing only the directories and symlinks that have to be
125 * traversed on the way to real exports:
126 */
127 if (unlikely(!d_is_dir(dentry) &&
128 !d_is_symlink(dentry)))
129 return nfserr_stale;
130 /*
131 * A pseudoroot export gives permission to access only one
132 * single directory; the kernel has to make another upcall
133 * before granting access to anything else under it:
134 */
135 if (unlikely(dentry != exp->ex_path.dentry))
136 return nfserr_stale;
137 return nfs_ok;
138 }
139
140 /*
141 * Use the given filehandle to look up the corresponding export and
142 * dentry. On success, the results are used to set fh_export and
143 * fh_dentry.
144 */
nfsd_set_fh_dentry(struct svc_rqst * rqstp,struct net * net,struct svc_cred * cred,struct auth_domain * client,struct auth_domain * gssclient,struct svc_fh * fhp)145 static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct net *net,
146 struct svc_cred *cred,
147 struct auth_domain *client,
148 struct auth_domain *gssclient,
149 struct svc_fh *fhp)
150 {
151 struct knfsd_fh *fh = &fhp->fh_handle;
152 struct fid *fid = NULL;
153 struct svc_export *exp;
154 struct dentry *dentry;
155 int fileid_type;
156 int data_left = fh->fh_size/4;
157 int len;
158 __be32 error;
159
160 error = nfserr_badhandle;
161 if (fh->fh_size == 0)
162 return nfserr_nofilehandle;
163
164 if (fh->fh_version != 1)
165 return error;
166
167 if (--data_left < 0)
168 return error;
169 if (fh->fh_auth_type != 0)
170 return error;
171 len = key_len(fh->fh_fsid_type) / 4;
172 if (len == 0)
173 return error;
174 if (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
175 /* deprecated, convert to type 3 */
176 len = key_len(FSID_ENCODE_DEV)/4;
177 fh->fh_fsid_type = FSID_ENCODE_DEV;
178 /*
179 * struct knfsd_fh uses host-endian fields, which are
180 * sometimes used to hold net-endian values. This
181 * confuses sparse, so we must use __force here to
182 * keep it from complaining.
183 */
184 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl((__force __be32)fh->fh_fsid[0]),
185 ntohl((__force __be32)fh->fh_fsid[1])));
186 fh->fh_fsid[1] = fh->fh_fsid[2];
187 }
188 data_left -= len;
189 if (data_left < 0)
190 return error;
191 exp = rqst_exp_find(rqstp ? &rqstp->rq_chandle : NULL,
192 net, client, gssclient,
193 fh->fh_fsid_type, fh->fh_fsid);
194 fid = (struct fid *)(fh->fh_fsid + len);
195
196 error = nfserr_stale;
197 if (IS_ERR(exp)) {
198 trace_nfsd_set_fh_dentry_badexport(rqstp, fhp, PTR_ERR(exp));
199
200 if (PTR_ERR(exp) == -ENOENT)
201 return error;
202
203 return nfserrno(PTR_ERR(exp));
204 }
205
206 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
207 /* Elevate privileges so that the lack of 'r' or 'x'
208 * permission on some parent directory will
209 * not stop exportfs_decode_fh from being able
210 * to reconnect a directory into the dentry cache.
211 * The same problem can affect "SUBTREECHECK" exports,
212 * but as nfsd_acceptable depends on correct
213 * access control settings being in effect, we cannot
214 * fix that case easily.
215 */
216 struct cred *new = prepare_creds();
217 if (!new) {
218 error = nfserrno(-ENOMEM);
219 goto out;
220 }
221 new->cap_effective =
222 cap_raise_nfsd_set(new->cap_effective,
223 new->cap_permitted);
224 put_cred(override_creds(new));
225 put_cred(new);
226 } else {
227 error = nfsd_setuser_and_check_port(rqstp, cred, exp);
228 if (error)
229 goto out;
230 }
231
232 /*
233 * Look up the dentry using the NFS file handle.
234 */
235 error = nfserr_badhandle;
236
237 fileid_type = fh->fh_fileid_type;
238
239 if (fileid_type == FILEID_ROOT)
240 dentry = dget(exp->ex_path.dentry);
241 else {
242 dentry = exportfs_decode_fh_raw(exp->ex_path.mnt, fid,
243 data_left, fileid_type, 0,
244 nfsd_acceptable, exp);
245 if (IS_ERR_OR_NULL(dentry)) {
246 trace_nfsd_set_fh_dentry_badhandle(rqstp, fhp,
247 dentry ? PTR_ERR(dentry) : -ESTALE);
248 switch (PTR_ERR(dentry)) {
249 case -ENOMEM:
250 case -ETIMEDOUT:
251 break;
252 default:
253 dentry = ERR_PTR(-ESTALE);
254 }
255 }
256 }
257 if (dentry == NULL)
258 goto out;
259 if (IS_ERR(dentry)) {
260 if (PTR_ERR(dentry) != -EINVAL)
261 error = nfserrno(PTR_ERR(dentry));
262 goto out;
263 }
264
265 if (d_is_dir(dentry) &&
266 (dentry->d_flags & DCACHE_DISCONNECTED)) {
267 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
268 dentry);
269 }
270
271 fhp->fh_dentry = dentry;
272 fhp->fh_export = exp;
273
274 switch (fhp->fh_maxsize) {
275 case NFS4_FHSIZE:
276 if (dentry->d_sb->s_export_op->flags & EXPORT_OP_NOATOMIC_ATTR)
277 fhp->fh_no_atomic_attr = true;
278 fhp->fh_64bit_cookies = true;
279 break;
280 case NFS3_FHSIZE:
281 if (dentry->d_sb->s_export_op->flags & EXPORT_OP_NOWCC)
282 fhp->fh_no_wcc = true;
283 fhp->fh_64bit_cookies = true;
284 if (exp->ex_flags & NFSEXP_V4ROOT)
285 goto out;
286 break;
287 case NFS_FHSIZE:
288 fhp->fh_no_wcc = true;
289 if (EX_WGATHER(exp))
290 fhp->fh_use_wgather = true;
291 if (exp->ex_flags & NFSEXP_V4ROOT)
292 goto out;
293 }
294
295 return 0;
296 out:
297 exp_put(exp);
298 return error;
299 }
300
301 /**
302 * __fh_verify - filehandle lookup and access checking
303 * @rqstp: RPC transaction context, or NULL
304 * @net: net namespace in which to perform the export lookup
305 * @cred: RPC user credential
306 * @client: RPC auth domain
307 * @gssclient: RPC GSS auth domain, or NULL
308 * @fhp: filehandle to be verified
309 * @type: expected type of object pointed to by filehandle
310 * @access: type of access needed to object
311 *
312 * See fh_verify() for further descriptions of @fhp, @type, and @access.
313 */
314 static __be32
__fh_verify(struct svc_rqst * rqstp,struct net * net,struct svc_cred * cred,struct auth_domain * client,struct auth_domain * gssclient,struct svc_fh * fhp,umode_t type,int access)315 __fh_verify(struct svc_rqst *rqstp,
316 struct net *net, struct svc_cred *cred,
317 struct auth_domain *client,
318 struct auth_domain *gssclient,
319 struct svc_fh *fhp, umode_t type, int access)
320 {
321 struct nfsd_net *nn = net_generic(net, nfsd_net_id);
322 struct svc_export *exp = NULL;
323 struct dentry *dentry;
324 __be32 error;
325
326 if (!fhp->fh_dentry) {
327 error = nfsd_set_fh_dentry(rqstp, net, cred, client,
328 gssclient, fhp);
329 if (error)
330 goto out;
331 }
332 dentry = fhp->fh_dentry;
333 exp = fhp->fh_export;
334
335 trace_nfsd_fh_verify(rqstp, fhp, type, access);
336
337 /*
338 * We still have to do all these permission checks, even when
339 * fh_dentry is already set:
340 * - fh_verify may be called multiple times with different
341 * "access" arguments (e.g. nfsd_proc_create calls
342 * fh_verify(...,NFSD_MAY_EXEC) first, then later (in
343 * nfsd_create) calls fh_verify(...,NFSD_MAY_CREATE).
344 * - in the NFSv4 case, the filehandle may have been filled
345 * in by fh_compose, and given a dentry, but further
346 * compound operations performed with that filehandle
347 * still need permissions checks. In the worst case, a
348 * mountpoint crossing may have changed the export
349 * options, and we may now need to use a different uid
350 * (for example, if different id-squashing options are in
351 * effect on the new filesystem).
352 */
353 error = check_pseudo_root(dentry, exp);
354 if (error)
355 goto out;
356
357 error = nfsd_setuser_and_check_port(rqstp, cred, exp);
358 if (error)
359 goto out;
360
361 error = nfsd_mode_check(dentry, type);
362 if (error)
363 goto out;
364
365 /*
366 * pseudoflavor restrictions are not enforced on NLM,
367 * which clients virtually always use auth_sys for,
368 * even while using RPCSEC_GSS for NFS.
369 */
370 if (access & NFSD_MAY_LOCK || access & NFSD_MAY_BYPASS_GSS)
371 goto skip_pseudoflavor_check;
372 /*
373 * Clients may expect to be able to use auth_sys during mount,
374 * even if they use gss for everything else; see section 2.3.2
375 * of rfc 2623.
376 */
377 if (access & NFSD_MAY_BYPASS_GSS_ON_ROOT
378 && exp->ex_path.dentry == dentry)
379 goto skip_pseudoflavor_check;
380
381 error = check_nfsd_access(exp, rqstp);
382 if (error)
383 goto out;
384
385 skip_pseudoflavor_check:
386 /* Finally, check access permissions. */
387 error = nfsd_permission(cred, exp, dentry, access);
388 out:
389 trace_nfsd_fh_verify_err(rqstp, fhp, type, access, error);
390 if (error == nfserr_stale)
391 nfsd_stats_fh_stale_inc(nn, exp);
392 return error;
393 }
394
395 /**
396 * fh_verify_local - filehandle lookup and access checking
397 * @net: net namespace in which to perform the export lookup
398 * @cred: RPC user credential
399 * @client: RPC auth domain
400 * @fhp: filehandle to be verified
401 * @type: expected type of object pointed to by filehandle
402 * @access: type of access needed to object
403 *
404 * This API can be used by callers who do not have an RPC
405 * transaction context (ie are not running in an nfsd thread).
406 *
407 * See fh_verify() for further descriptions of @fhp, @type, and @access.
408 */
409 __be32
fh_verify_local(struct net * net,struct svc_cred * cred,struct auth_domain * client,struct svc_fh * fhp,umode_t type,int access)410 fh_verify_local(struct net *net, struct svc_cred *cred,
411 struct auth_domain *client, struct svc_fh *fhp,
412 umode_t type, int access)
413 {
414 return __fh_verify(NULL, net, cred, client, NULL,
415 fhp, type, access);
416 }
417
418 /**
419 * fh_verify - filehandle lookup and access checking
420 * @rqstp: pointer to current rpc request
421 * @fhp: filehandle to be verified
422 * @type: expected type of object pointed to by filehandle
423 * @access: type of access needed to object
424 *
425 * Look up a dentry from the on-the-wire filehandle, check the client's
426 * access to the export, and set the current task's credentials.
427 *
428 * Regardless of success or failure of fh_verify(), fh_put() should be
429 * called on @fhp when the caller is finished with the filehandle.
430 *
431 * fh_verify() may be called multiple times on a given filehandle, for
432 * example, when processing an NFSv4 compound. The first call will look
433 * up a dentry using the on-the-wire filehandle. Subsequent calls will
434 * skip the lookup and just perform the other checks and possibly change
435 * the current task's credentials.
436 *
437 * @type specifies the type of object expected using one of the S_IF*
438 * constants defined in include/linux/stat.h. The caller may use zero
439 * to indicate that it doesn't care, or a negative integer to indicate
440 * that it expects something not of the given type.
441 *
442 * @access is formed from the NFSD_MAY_* constants defined in
443 * fs/nfsd/vfs.h.
444 */
445 __be32
fh_verify(struct svc_rqst * rqstp,struct svc_fh * fhp,umode_t type,int access)446 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type, int access)
447 {
448 return __fh_verify(rqstp, SVC_NET(rqstp), &rqstp->rq_cred,
449 rqstp->rq_client, rqstp->rq_gssclient,
450 fhp, type, access);
451 }
452
453 /*
454 * Compose a file handle for an NFS reply.
455 *
456 * Note that when first composed, the dentry may not yet have
457 * an inode. In this case a call to fh_update should be made
458 * before the fh goes out on the wire ...
459 */
_fh_update(struct svc_fh * fhp,struct svc_export * exp,struct dentry * dentry)460 static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
461 struct dentry *dentry)
462 {
463 if (dentry != exp->ex_path.dentry) {
464 struct fid *fid = (struct fid *)
465 (fhp->fh_handle.fh_fsid + fhp->fh_handle.fh_size/4 - 1);
466 int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
467 int fh_flags = (exp->ex_flags & NFSEXP_NOSUBTREECHECK) ? 0 :
468 EXPORT_FH_CONNECTABLE;
469 int fileid_type =
470 exportfs_encode_fh(dentry, fid, &maxsize, fh_flags);
471
472 fhp->fh_handle.fh_fileid_type =
473 fileid_type > 0 ? fileid_type : FILEID_INVALID;
474 fhp->fh_handle.fh_size += maxsize * 4;
475 } else {
476 fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
477 }
478 }
479
is_root_export(struct svc_export * exp)480 static bool is_root_export(struct svc_export *exp)
481 {
482 return exp->ex_path.dentry == exp->ex_path.dentry->d_sb->s_root;
483 }
484
exp_sb(struct svc_export * exp)485 static struct super_block *exp_sb(struct svc_export *exp)
486 {
487 return exp->ex_path.dentry->d_sb;
488 }
489
fsid_type_ok_for_exp(u8 fsid_type,struct svc_export * exp)490 static bool fsid_type_ok_for_exp(u8 fsid_type, struct svc_export *exp)
491 {
492 switch (fsid_type) {
493 case FSID_DEV:
494 if (!old_valid_dev(exp_sb(exp)->s_dev))
495 return false;
496 fallthrough;
497 case FSID_MAJOR_MINOR:
498 case FSID_ENCODE_DEV:
499 return exp_sb(exp)->s_type->fs_flags & FS_REQUIRES_DEV;
500 case FSID_NUM:
501 return exp->ex_flags & NFSEXP_FSID;
502 case FSID_UUID8:
503 case FSID_UUID16:
504 if (!is_root_export(exp))
505 return false;
506 fallthrough;
507 case FSID_UUID4_INUM:
508 case FSID_UUID16_INUM:
509 return exp->ex_uuid != NULL;
510 }
511 return true;
512 }
513
514
set_version_and_fsid_type(struct svc_fh * fhp,struct svc_export * exp,struct svc_fh * ref_fh)515 static void set_version_and_fsid_type(struct svc_fh *fhp, struct svc_export *exp, struct svc_fh *ref_fh)
516 {
517 u8 version;
518 u8 fsid_type;
519 retry:
520 version = 1;
521 if (ref_fh && ref_fh->fh_export == exp) {
522 version = ref_fh->fh_handle.fh_version;
523 fsid_type = ref_fh->fh_handle.fh_fsid_type;
524
525 ref_fh = NULL;
526
527 switch (version) {
528 case 0xca:
529 fsid_type = FSID_DEV;
530 break;
531 case 1:
532 break;
533 default:
534 goto retry;
535 }
536
537 /*
538 * As the fsid -> filesystem mapping was guided by
539 * user-space, there is no guarantee that the filesystem
540 * actually supports that fsid type. If it doesn't we
541 * loop around again without ref_fh set.
542 */
543 if (!fsid_type_ok_for_exp(fsid_type, exp))
544 goto retry;
545 } else if (exp->ex_flags & NFSEXP_FSID) {
546 fsid_type = FSID_NUM;
547 } else if (exp->ex_uuid) {
548 if (fhp->fh_maxsize >= 64) {
549 if (is_root_export(exp))
550 fsid_type = FSID_UUID16;
551 else
552 fsid_type = FSID_UUID16_INUM;
553 } else {
554 if (is_root_export(exp))
555 fsid_type = FSID_UUID8;
556 else
557 fsid_type = FSID_UUID4_INUM;
558 }
559 } else if (!old_valid_dev(exp_sb(exp)->s_dev))
560 /* for newer device numbers, we must use a newer fsid format */
561 fsid_type = FSID_ENCODE_DEV;
562 else
563 fsid_type = FSID_DEV;
564 fhp->fh_handle.fh_version = version;
565 if (version)
566 fhp->fh_handle.fh_fsid_type = fsid_type;
567 }
568
569 __be32
fh_compose(struct svc_fh * fhp,struct svc_export * exp,struct dentry * dentry,struct svc_fh * ref_fh)570 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
571 struct svc_fh *ref_fh)
572 {
573 /* ref_fh is a reference file handle.
574 * if it is non-null and for the same filesystem, then we should compose
575 * a filehandle which is of the same version, where possible.
576 */
577
578 struct inode * inode = d_inode(dentry);
579 dev_t ex_dev = exp_sb(exp)->s_dev;
580
581 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %pd2, ino=%ld)\n",
582 MAJOR(ex_dev), MINOR(ex_dev),
583 (long) d_inode(exp->ex_path.dentry)->i_ino,
584 dentry,
585 (inode ? inode->i_ino : 0));
586
587 /* Choose filehandle version and fsid type based on
588 * the reference filehandle (if it is in the same export)
589 * or the export options.
590 */
591 set_version_and_fsid_type(fhp, exp, ref_fh);
592
593 /* If we have a ref_fh, then copy the fh_no_wcc setting from it. */
594 fhp->fh_no_wcc = ref_fh ? ref_fh->fh_no_wcc : false;
595
596 if (ref_fh == fhp)
597 fh_put(ref_fh);
598
599 if (fhp->fh_dentry) {
600 printk(KERN_ERR "fh_compose: fh %pd2 not initialized!\n",
601 dentry);
602 }
603 if (fhp->fh_maxsize < NFS_FHSIZE)
604 printk(KERN_ERR "fh_compose: called with maxsize %d! %pd2\n",
605 fhp->fh_maxsize,
606 dentry);
607
608 fhp->fh_dentry = dget(dentry); /* our internal copy */
609 fhp->fh_export = exp_get(exp);
610
611 fhp->fh_handle.fh_size =
612 key_len(fhp->fh_handle.fh_fsid_type) + 4;
613 fhp->fh_handle.fh_auth_type = 0;
614
615 mk_fsid(fhp->fh_handle.fh_fsid_type,
616 fhp->fh_handle.fh_fsid,
617 ex_dev,
618 d_inode(exp->ex_path.dentry)->i_ino,
619 exp->ex_fsid, exp->ex_uuid);
620
621 if (inode)
622 _fh_update(fhp, exp, dentry);
623 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID) {
624 fh_put(fhp);
625 return nfserr_stale;
626 }
627
628 return 0;
629 }
630
631 /*
632 * Update file handle information after changing a dentry.
633 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
634 */
635 __be32
fh_update(struct svc_fh * fhp)636 fh_update(struct svc_fh *fhp)
637 {
638 struct dentry *dentry;
639
640 if (!fhp->fh_dentry)
641 goto out_bad;
642
643 dentry = fhp->fh_dentry;
644 if (d_really_is_negative(dentry))
645 goto out_negative;
646 if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
647 return 0;
648
649 _fh_update(fhp, fhp->fh_export, dentry);
650 if (fhp->fh_handle.fh_fileid_type == FILEID_INVALID)
651 return nfserr_stale;
652 return 0;
653 out_bad:
654 printk(KERN_ERR "fh_update: fh not verified!\n");
655 return nfserr_serverfault;
656 out_negative:
657 printk(KERN_ERR "fh_update: %pd2 still negative!\n",
658 dentry);
659 return nfserr_serverfault;
660 }
661
662 /**
663 * fh_fill_pre_attrs - Fill in pre-op attributes
664 * @fhp: file handle to be updated
665 *
666 */
fh_fill_pre_attrs(struct svc_fh * fhp)667 __be32 __must_check fh_fill_pre_attrs(struct svc_fh *fhp)
668 {
669 bool v4 = (fhp->fh_maxsize == NFS4_FHSIZE);
670 struct inode *inode;
671 struct kstat stat;
672 __be32 err;
673
674 if (fhp->fh_no_wcc || fhp->fh_pre_saved)
675 return nfs_ok;
676
677 inode = d_inode(fhp->fh_dentry);
678 err = fh_getattr(fhp, &stat);
679 if (err)
680 return err;
681
682 if (v4)
683 fhp->fh_pre_change = nfsd4_change_attribute(&stat, inode);
684
685 fhp->fh_pre_mtime = stat.mtime;
686 fhp->fh_pre_ctime = stat.ctime;
687 fhp->fh_pre_size = stat.size;
688 fhp->fh_pre_saved = true;
689 return nfs_ok;
690 }
691
692 /**
693 * fh_fill_post_attrs - Fill in post-op attributes
694 * @fhp: file handle to be updated
695 *
696 */
fh_fill_post_attrs(struct svc_fh * fhp)697 __be32 fh_fill_post_attrs(struct svc_fh *fhp)
698 {
699 bool v4 = (fhp->fh_maxsize == NFS4_FHSIZE);
700 struct inode *inode = d_inode(fhp->fh_dentry);
701 __be32 err;
702
703 if (fhp->fh_no_wcc)
704 return nfs_ok;
705
706 if (fhp->fh_post_saved)
707 printk("nfsd: inode locked twice during operation.\n");
708
709 err = fh_getattr(fhp, &fhp->fh_post_attr);
710 if (err)
711 return err;
712
713 fhp->fh_post_saved = true;
714 if (v4)
715 fhp->fh_post_change =
716 nfsd4_change_attribute(&fhp->fh_post_attr, inode);
717 return nfs_ok;
718 }
719
720 /**
721 * fh_fill_both_attrs - Fill pre-op and post-op attributes
722 * @fhp: file handle to be updated
723 *
724 * This is used when the directory wasn't changed, but wcc attributes
725 * are needed anyway.
726 */
fh_fill_both_attrs(struct svc_fh * fhp)727 __be32 __must_check fh_fill_both_attrs(struct svc_fh *fhp)
728 {
729 __be32 err;
730
731 err = fh_fill_post_attrs(fhp);
732 if (err)
733 return err;
734
735 fhp->fh_pre_change = fhp->fh_post_change;
736 fhp->fh_pre_mtime = fhp->fh_post_attr.mtime;
737 fhp->fh_pre_ctime = fhp->fh_post_attr.ctime;
738 fhp->fh_pre_size = fhp->fh_post_attr.size;
739 fhp->fh_pre_saved = true;
740 return nfs_ok;
741 }
742
743 /*
744 * Release a file handle.
745 */
746 void
fh_put(struct svc_fh * fhp)747 fh_put(struct svc_fh *fhp)
748 {
749 struct dentry * dentry = fhp->fh_dentry;
750 struct svc_export * exp = fhp->fh_export;
751 if (dentry) {
752 fhp->fh_dentry = NULL;
753 dput(dentry);
754 fh_clear_pre_post_attrs(fhp);
755 }
756 fh_drop_write(fhp);
757 if (exp) {
758 exp_put(exp);
759 fhp->fh_export = NULL;
760 }
761 fhp->fh_no_wcc = false;
762 return;
763 }
764
765 /*
766 * Shorthand for dprintk()'s
767 */
SVCFH_fmt(struct svc_fh * fhp)768 char * SVCFH_fmt(struct svc_fh *fhp)
769 {
770 struct knfsd_fh *fh = &fhp->fh_handle;
771 static char buf[2+1+1+64*3+1];
772
773 if (fh->fh_size < 0 || fh->fh_size> 64)
774 return "bad-fh";
775 sprintf(buf, "%d: %*ph", fh->fh_size, fh->fh_size, fh->fh_raw);
776 return buf;
777 }
778
fsid_source(const struct svc_fh * fhp)779 enum fsid_source fsid_source(const struct svc_fh *fhp)
780 {
781 if (fhp->fh_handle.fh_version != 1)
782 return FSIDSOURCE_DEV;
783 switch(fhp->fh_handle.fh_fsid_type) {
784 case FSID_DEV:
785 case FSID_ENCODE_DEV:
786 case FSID_MAJOR_MINOR:
787 if (exp_sb(fhp->fh_export)->s_type->fs_flags & FS_REQUIRES_DEV)
788 return FSIDSOURCE_DEV;
789 break;
790 case FSID_NUM:
791 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
792 return FSIDSOURCE_FSID;
793 break;
794 default:
795 break;
796 }
797 /* either a UUID type filehandle, or the filehandle doesn't
798 * match the export.
799 */
800 if (fhp->fh_export->ex_flags & NFSEXP_FSID)
801 return FSIDSOURCE_FSID;
802 if (fhp->fh_export->ex_uuid)
803 return FSIDSOURCE_UUID;
804 return FSIDSOURCE_DEV;
805 }
806
807 /*
808 * We could use i_version alone as the change attribute. However, i_version
809 * can go backwards on a regular file after an unclean shutdown. On its own
810 * that doesn't necessarily cause a problem, but if i_version goes backwards
811 * and then is incremented again it could reuse a value that was previously
812 * used before boot, and a client who queried the two values might incorrectly
813 * assume nothing changed.
814 *
815 * By using both ctime and the i_version counter we guarantee that as long as
816 * time doesn't go backwards we never reuse an old value. If the filesystem
817 * advertises STATX_ATTR_CHANGE_MONOTONIC, then this mitigation is not
818 * needed.
819 *
820 * We only need to do this for regular files as well. For directories, we
821 * assume that the new change attr is always logged to stable storage in some
822 * fashion before the results can be seen.
823 */
nfsd4_change_attribute(const struct kstat * stat,const struct inode * inode)824 u64 nfsd4_change_attribute(const struct kstat *stat, const struct inode *inode)
825 {
826 u64 chattr;
827
828 if (stat->result_mask & STATX_CHANGE_COOKIE) {
829 chattr = stat->change_cookie;
830 if (S_ISREG(inode->i_mode) &&
831 !(stat->attributes & STATX_ATTR_CHANGE_MONOTONIC)) {
832 chattr += (u64)stat->ctime.tv_sec << 30;
833 chattr += stat->ctime.tv_nsec;
834 }
835 } else {
836 chattr = time_to_chattr(&stat->ctime);
837 }
838 return chattr;
839 }
840