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[mirror_ubuntu-bionic-kernel.git] / fs / nfsd / nfsfh.c
CommitLineData
1da177e4
LT		 1/*
2 * linux/fs/nfsd/nfsfh.c
3 *
4 * NFS server file handle treatment.
5 *
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
10 */
11
12#include <linux/sched.h>
13#include <linux/slab.h>
14#include <linux/smp_lock.h>
15#include <linux/fs.h>
16#include <linux/unistd.h>
17#include <linux/string.h>
18#include <linux/stat.h>
19#include <linux/dcache.h>
20#include <linux/mount.h>
21#include <asm/pgtable.h>
22
23#include <linux/sunrpc/svc.h>
24#include <linux/nfsd/nfsd.h>
25
26#define NFSDDBG_FACILITY NFSDDBG_FH
1da177e4
LT		 27
28
29static int nfsd_nr_verified;
30static int nfsd_nr_put;
31
32extern struct export_operations export_op_default;
33
34#define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
35
36/*
37 * our acceptability function.
38 * if NOSUBTREECHECK, accept anything
39 * if not, require that we can walk up to exp->ex_dentry
40 * doing some checks on the 'x' bits
41 */
42static int nfsd_acceptable(void *expv, struct dentry *dentry)
43{
44 struct svc_export *exp = expv;
45 int rv;
46 struct dentry *tdentry;
47 struct dentry *parent;
48
49 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
50 return 1;
51
52 tdentry = dget(dentry);
53 while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
54 /* make sure parents give x permission to user */
55 int err;
56 parent = dget_parent(tdentry);
57 err = permission(parent->d_inode, MAY_EXEC, NULL);
58 if (err < 0) {
59 dput(parent);
60 break;
61 }
62 dput(tdentry);
63 tdentry = parent;
64 }
65 if (tdentry != exp->ex_dentry)
66 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
67 rv = (tdentry == exp->ex_dentry);
68 dput(tdentry);
69 return rv;
70}
71
72/* Type check. The correct error return for type mismatches does not seem to be
73 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
74 * comment in the NFSv3 spec says this is incorrect (implementation notes for
75 * the write call).
76 */
83b11340 77static inline __be32
1da177e4
LT		 78nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
79{
80 /* Type can be negative when creating hardlinks - not to a dir */
81 if (type > 0 && (mode & S_IFMT) != type) {
82 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
83 return nfserr_symlink;
84 else if (type == S_IFDIR)
85 return nfserr_notdir;
86 else if ((mode & S_IFMT) == S_IFDIR)
87 return nfserr_isdir;
88 else
89 return nfserr_inval;
90 }
91 if (type < 0 && (mode & S_IFMT) == -type) {
92 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
93 return nfserr_symlink;
94 else if (type == -S_IFDIR)
95 return nfserr_isdir;
96 else
97 return nfserr_notdir;
98 }
99 return 0;
100}
101
102/*
103 * Perform sanity checks on the dentry in a client's file handle.
104 *
105 * Note that the file handle dentry may need to be freed even after
106 * an error return.
107 *
108 * This is only called at the start of an nfsproc call, so fhp points to
109 * a svc_fh which is all 0 except for the over-the-wire file handle.
110 */
83b11340 111__be32
1da177e4
LT		 112fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
113{
114 struct knfsd_fh *fh = &fhp->fh_handle;
115 struct svc_export *exp = NULL;
116 struct dentry *dentry;
83b11340 117 __be32 error = 0;
1da177e4
LT		 118
119 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
120
121 /* keep this filehandle for possible reference when encoding attributes */
122 rqstp->rq_reffh = fh;
123
124 if (!fhp->fh_dentry) {
125 __u32 *datap=NULL;
126 __u32 tfh[3]; /* filehandle fragment for oldstyle filehandles */
127 int fileid_type;
128 int data_left = fh->fh_size/4;
129
130 error = nfserr_stale;
131 if (rqstp->rq_client == NULL)
132 goto out;
133 if (rqstp->rq_vers > 2)
134 error = nfserr_badhandle;
135 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
136 return nfserr_nofilehandle;
137
138 if (fh->fh_version == 1) {
139 int len;
140 datap = fh->fh_auth;
141 if (--data_left<0) goto out;
142 switch (fh->fh_auth_type) {
143 case 0: break;
144 default: goto out;
145 }
146 len = key_len(fh->fh_fsid_type) / 4;
147 if (len == 0) goto out;
148 if (fh->fh_fsid_type == 2) {
149 /* deprecated, convert to type 3 */
150 len = 3;
151 fh->fh_fsid_type = 3;
152 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
153 fh->fh_fsid[1] = fh->fh_fsid[2];
154 }
155 if ((data_left -= len)<0) goto out;
156 exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
157 datap += len;
158 } else {
159 dev_t xdev;
160 ino_t xino;
161 if (fh->fh_size != NFS_FHSIZE)
162 goto out;
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_v0(tfh, xdev, xino);
167 exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle);
168 }
169
e0bb89ef
BF		 170 if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
171 || PTR_ERR(exp) == -ETIMEDOUT)) {
172 error = nfserrno(PTR_ERR(exp));
1da177e4 173 goto out;
e0bb89ef 174 }
1da177e4
LT		 175
176 error = nfserr_stale;
177 if (!exp || IS_ERR(exp))
178 goto out;
179
180 /* Check if the request originated from a secure port. */
181 error = nfserr_perm;
182 if (!rqstp->rq_secure && EX_SECURE(exp)) {
183 printk(KERN_WARNING
184 "nfsd: request from insecure port (%u.%u.%u.%u:%d)!\n",
185 NIPQUAD(rqstp->rq_addr.sin_addr.s_addr),
186 ntohs(rqstp->rq_addr.sin_port));
187 goto out;
188 }
189
d1bbf14f
N		 190 /* Set user creds for this exportpoint */
191 error = nfserrno(nfsd_setuser(rqstp, exp));
192 if (error)
193 goto out;
194
1da177e4
LT		 195 /*
196 * Look up the dentry using the NFS file handle.
197 */
198 error = nfserr_stale;
199 if (rqstp->rq_vers > 2)
200 error = nfserr_badhandle;
201
202 if (fh->fh_version != 1) {
203 tfh[0] = fh->ofh_ino;
204 tfh[1] = fh->ofh_generation;
205 tfh[2] = fh->ofh_dirino;
206 datap = tfh;
207 data_left = 3;
208 if (fh->ofh_dirino == 0)
209 fileid_type = 1;
210 else
211 fileid_type = 2;
212 } else
213 fileid_type = fh->fh_fileid_type;
214
215 if (fileid_type == 0)
216 dentry = dget(exp->ex_dentry);
217 else {
218 struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
219 dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
220 datap, data_left,
221 fileid_type,
222 nfsd_acceptable, exp);
223 }
224 if (dentry == NULL)
225 goto out;
226 if (IS_ERR(dentry)) {
227 if (PTR_ERR(dentry) != -EINVAL)
228 error = nfserrno(PTR_ERR(dentry));
229 goto out;
230 }
34e9a63b 231
1da177e4
LT		 232 if (S_ISDIR(dentry->d_inode->i_mode) &&
233 (dentry->d_flags & DCACHE_DISCONNECTED)) {
234 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
235 dentry->d_parent->d_name.name, dentry->d_name.name);
236 }
1da177e4
LT		 237
238 fhp->fh_dentry = dentry;
239 fhp->fh_export = exp;
240 nfsd_nr_verified++;
241 } else {
242 /* just rechecking permissions
243 * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
244 */
245 dprintk("nfsd: fh_verify - just checking\n");
246 dentry = fhp->fh_dentry;
247 exp = fhp->fh_export;
d1bbf14f
N		 248 /* Set user creds for this exportpoint; necessary even
249 * in the "just checking" case because this may be a
250 * filehandle that was created by fh_compose, and that
251 * is about to be used in another nfsv4 compound
252 * operation */
253 error = nfserrno(nfsd_setuser(rqstp, exp));
254 if (error)
255 goto out;
1da177e4
LT		 256 }
257 cache_get(&exp->h);
258
7fc90ec9 259
1da177e4
LT		 260 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
261 if (error)
262 goto out;
263
264 /* Finally, check access permissions. */
265 error = nfsd_permission(exp, dentry, access);
266
1da177e4 267 if (error) {
34e9a63b
N		 268 dprintk("fh_verify: %s/%s permission failure, "
269 "acc=%x, error=%d\n",
270 dentry->d_parent->d_name.name,
271 dentry->d_name.name,
272 access, (error >> 24));
1da177e4 273 }
1da177e4
LT		 274out:
275 if (exp && !IS_ERR(exp))
276 exp_put(exp);
277 if (error == nfserr_stale)
278 nfsdstats.fh_stale++;
279 return error;
280}
281
282
283/*
284 * Compose a file handle for an NFS reply.
285 *
286 * Note that when first composed, the dentry may not yet have
287 * an inode. In this case a call to fh_update should be made
288 * before the fh goes out on the wire ...
289 */
290static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
291 __u32 *datap, int *maxsize)
292{
293 struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
294
295 if (dentry == exp->ex_dentry) {
296 *maxsize = 0;
297 return 0;
298 }
299
300 return CALL(nop,encode_fh)(dentry, datap, maxsize,
301 !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
302}
303
304/*
305 * for composing old style file handles
306 */
307static inline void _fh_update_old(struct dentry *dentry,
308 struct svc_export *exp,
309 struct knfsd_fh *fh)
310{
311 fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
312 fh->ofh_generation = dentry->d_inode->i_generation;
313 if (S_ISDIR(dentry->d_inode->i_mode) ||
314 (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
315 fh->ofh_dirino = 0;
316}
317
83b11340 318__be32
1da177e4
LT		 319fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh)
320{
321 /* ref_fh is a reference file handle.
7e405364
N		 322 * if it is non-null and for the same filesystem, then we should compose
323 * a filehandle which is of the same version, where possible.
1da177e4
LT		 324 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
325 * Then create a 32byte filehandle using nfs_fhbase_old
326 *
327 */
328
329 u8 ref_fh_version = 0;
330 u8 ref_fh_fsid_type = 0;
331 struct inode * inode = dentry->d_inode;
332 struct dentry *parent = dentry->d_parent;
333 __u32 *datap;
334 dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
335
336 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
337 MAJOR(ex_dev), MINOR(ex_dev),
338 (long) exp->ex_dentry->d_inode->i_ino,
339 parent->d_name.name, dentry->d_name.name,
340 (inode ? inode->i_ino : 0));
341
7e405364 342 if (ref_fh && ref_fh->fh_export == exp) {
1da177e4
LT		 343 ref_fh_version = ref_fh->fh_handle.fh_version;
344 if (ref_fh_version == 0xca)
345 ref_fh_fsid_type = 0;
346 else
347 ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
348 if (ref_fh_fsid_type > 3)
349 ref_fh_fsid_type = 0;
350
351 /* make sure ref_fh type works for given export */
352 if (ref_fh_fsid_type == 1 &&
353 !(exp->ex_flags & NFSEXP_FSID)) {
354 /* if we don't have an fsid, we cannot provide one... */
355 ref_fh_fsid_type = 0;
356 }
357 } else if (exp->ex_flags & NFSEXP_FSID)
358 ref_fh_fsid_type = 1;
359
360 if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
361 /* for newer device numbers, we must use a newer fsid format */
362 ref_fh_version = 1;
363 ref_fh_fsid_type = 3;
364 }
365 if (old_valid_dev(ex_dev) &&
366 (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
367 /* must use type1 for smaller device numbers */
368 ref_fh_fsid_type = 0;
369
370 if (ref_fh == fhp)
371 fh_put(ref_fh);
372
373 if (fhp->fh_locked || fhp->fh_dentry) {
374 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
375 parent->d_name.name, dentry->d_name.name);
376 }
377 if (fhp->fh_maxsize < NFS_FHSIZE)
378 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
379 fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
380
381 fhp->fh_dentry = dget(dentry); /* our internal copy */
382 fhp->fh_export = exp;
383 cache_get(&exp->h);
384
385 if (ref_fh_version == 0xca) {
386 /* old style filehandle please */
387 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
388 fhp->fh_handle.fh_size = NFS_FHSIZE;
389 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
390 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev);
391 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
392 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
393 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
394 if (inode)
395 _fh_update_old(dentry, exp, &fhp->fh_handle);
396 } else {
397 int len;
398 fhp->fh_handle.fh_version = 1;
399 fhp->fh_handle.fh_auth_type = 0;
400 datap = fhp->fh_handle.fh_auth+0;
401 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
402 switch (ref_fh_fsid_type) {
403 case 0:
404 /*
405 * fsid_type 0:
406 * 2byte major, 2byte minor, 4byte inode
407 */
408 mk_fsid_v0(datap, ex_dev,
409 exp->ex_dentry->d_inode->i_ino);
410 break;
411 case 1:
412 /* fsid_type 1 == 4 bytes filesystem id */
413 mk_fsid_v1(datap, exp->ex_fsid);
414 break;
415 case 2:
416 /*
417 * fsid_type 2:
418 * 4byte major, 4byte minor, 4byte inode
419 */
420 mk_fsid_v2(datap, ex_dev,
421 exp->ex_dentry->d_inode->i_ino);
422 break;
423 case 3:
424 /*
425 * fsid_type 3:
426 * 4byte devicenumber, 4byte inode
427 */
428 mk_fsid_v3(datap, ex_dev,
429 exp->ex_dentry->d_inode->i_ino);
430 break;
431 }
432 len = key_len(ref_fh_fsid_type);
433 datap += len/4;
434 fhp->fh_handle.fh_size = 4 + len;
435
436 if (inode) {
437 int size = (fhp->fh_maxsize-len-4)/4;
438 fhp->fh_handle.fh_fileid_type =
439 _fh_update(dentry, exp, datap, &size);
440 fhp->fh_handle.fh_size += size*4;
441 }
442 if (fhp->fh_handle.fh_fileid_type == 255)
443 return nfserr_opnotsupp;
444 }
445
446 nfsd_nr_verified++;
447 return 0;
448}
449
450/*
451 * Update file handle information after changing a dentry.
452 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
453 */
83b11340 454__be32
1da177e4
LT		 455fh_update(struct svc_fh *fhp)
456{
457 struct dentry *dentry;
458 __u32 *datap;
459
460 if (!fhp->fh_dentry)
461 goto out_bad;
462
463 dentry = fhp->fh_dentry;
464 if (!dentry->d_inode)
465 goto out_negative;
466 if (fhp->fh_handle.fh_version != 1) {
467 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
468 } else {
469 int size;
470 if (fhp->fh_handle.fh_fileid_type != 0)
4c9608b2 471 goto out;
1da177e4
LT		 472 datap = fhp->fh_handle.fh_auth+
473 fhp->fh_handle.fh_size/4 -1;
474 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
475 fhp->fh_handle.fh_fileid_type =
476 _fh_update(dentry, fhp->fh_export, datap, &size);
477 fhp->fh_handle.fh_size += size*4;
478 if (fhp->fh_handle.fh_fileid_type == 255)
479 return nfserr_opnotsupp;
480 }
481out:
482 return 0;
483
484out_bad:
485 printk(KERN_ERR "fh_update: fh not verified!\n");
486 goto out;
487out_negative:
488 printk(KERN_ERR "fh_update: %s/%s still negative!\n",
489 dentry->d_parent->d_name.name, dentry->d_name.name);
490 goto out;
1da177e4
LT		 491}
492
493/*
494 * Release a file handle.
495 */
496void
497fh_put(struct svc_fh *fhp)
498{
499 struct dentry * dentry = fhp->fh_dentry;
500 struct svc_export * exp = fhp->fh_export;
501 if (dentry) {
502 fh_unlock(fhp);
503 fhp->fh_dentry = NULL;
504 dput(dentry);
505#ifdef CONFIG_NFSD_V3
506 fhp->fh_pre_saved = 0;
507 fhp->fh_post_saved = 0;
508#endif
509 nfsd_nr_put++;
510 }
511 if (exp) {
baab935f 512 cache_put(&exp->h, &svc_export_cache);
1da177e4
LT		 513 fhp->fh_export = NULL;
514 }
515 return;
516}
517
518/*
519 * Shorthand for dprintk()'s
520 */
521char * SVCFH_fmt(struct svc_fh *fhp)
522{
523 struct knfsd_fh *fh = &fhp->fh_handle;
524
525 static char buf[80];
526 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
527 fh->fh_size,
528 fh->fh_base.fh_pad[0],
529 fh->fh_base.fh_pad[1],
530 fh->fh_base.fh_pad[2],
531 fh->fh_base.fh_pad[3],
532 fh->fh_base.fh_pad[4],
533 fh->fh_base.fh_pad[5]);
534 return buf;
535}
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