blob: 7a3e397b4ed38c709ed698ff8efe930f1849db88 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
27#define NFSD_PARANOIA 1
28/* #define NFSD_DEBUG_VERBOSE 1 */
29
30
31static int nfsd_nr_verified;
32static int nfsd_nr_put;
33
34extern struct export_operations export_op_default;
35
36#define CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
37
38/*
39 * our acceptability function.
40 * if NOSUBTREECHECK, accept anything
41 * if not, require that we can walk up to exp->ex_dentry
42 * doing some checks on the 'x' bits
43 */
44static int nfsd_acceptable(void *expv, struct dentry *dentry)
45{
46 struct svc_export *exp = expv;
47 int rv;
48 struct dentry *tdentry;
49 struct dentry *parent;
50
51 if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
52 return 1;
53
54 tdentry = dget(dentry);
55 while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
56 /* make sure parents give x permission to user */
57 int err;
58 parent = dget_parent(tdentry);
59 err = permission(parent->d_inode, MAY_EXEC, NULL);
60 if (err < 0) {
61 dput(parent);
62 break;
63 }
64 dput(tdentry);
65 tdentry = parent;
66 }
67 if (tdentry != exp->ex_dentry)
68 dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
69 rv = (tdentry == exp->ex_dentry);
70 dput(tdentry);
71 return rv;
72}
73
74/* Type check. The correct error return for type mismatches does not seem to be
75 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
76 * comment in the NFSv3 spec says this is incorrect (implementation notes for
77 * the write call).
78 */
79static inline int
80nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
81{
82 /* Type can be negative when creating hardlinks - not to a dir */
83 if (type > 0 && (mode & S_IFMT) != type) {
84 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
85 return nfserr_symlink;
86 else if (type == S_IFDIR)
87 return nfserr_notdir;
88 else if ((mode & S_IFMT) == S_IFDIR)
89 return nfserr_isdir;
90 else
91 return nfserr_inval;
92 }
93 if (type < 0 && (mode & S_IFMT) == -type) {
94 if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
95 return nfserr_symlink;
96 else if (type == -S_IFDIR)
97 return nfserr_isdir;
98 else
99 return nfserr_notdir;
100 }
101 return 0;
102}
103
104/*
105 * Perform sanity checks on the dentry in a client's file handle.
106 *
107 * Note that the file handle dentry may need to be freed even after
108 * an error return.
109 *
110 * This is only called at the start of an nfsproc call, so fhp points to
111 * a svc_fh which is all 0 except for the over-the-wire file handle.
112 */
113u32
114fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
115{
116 struct knfsd_fh *fh = &fhp->fh_handle;
117 struct svc_export *exp = NULL;
118 struct dentry *dentry;
119 u32 error = 0;
120
121 dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
122
123 /* keep this filehandle for possible reference when encoding attributes */
124 rqstp->rq_reffh = fh;
125
126 if (!fhp->fh_dentry) {
127 __u32 *datap=NULL;
128 __u32 tfh[3]; /* filehandle fragment for oldstyle filehandles */
129 int fileid_type;
130 int data_left = fh->fh_size/4;
131
132 error = nfserr_stale;
133 if (rqstp->rq_client == NULL)
134 goto out;
135 if (rqstp->rq_vers > 2)
136 error = nfserr_badhandle;
137 if (rqstp->rq_vers == 4 && fh->fh_size == 0)
138 return nfserr_nofilehandle;
139
140 if (fh->fh_version == 1) {
141 int len;
142 datap = fh->fh_auth;
143 if (--data_left<0) goto out;
144 switch (fh->fh_auth_type) {
145 case 0: break;
146 default: goto out;
147 }
148 len = key_len(fh->fh_fsid_type) / 4;
149 if (len == 0) goto out;
150 if (fh->fh_fsid_type == 2) {
151 /* deprecated, convert to type 3 */
152 len = 3;
153 fh->fh_fsid_type = 3;
154 fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
155 fh->fh_fsid[1] = fh->fh_fsid[2];
156 }
157 if ((data_left -= len)<0) goto out;
158 exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
159 datap += len;
160 } else {
161 dev_t xdev;
162 ino_t xino;
163 if (fh->fh_size != NFS_FHSIZE)
164 goto out;
165 /* assume old filehandle format */
166 xdev = old_decode_dev(fh->ofh_xdev);
167 xino = u32_to_ino_t(fh->ofh_xino);
168 mk_fsid_v0(tfh, xdev, xino);
169 exp = exp_find(rqstp->rq_client, 0, tfh, &rqstp->rq_chandle);
170 }
171
172 error = nfserr_dropit;
173 if (IS_ERR(exp) && PTR_ERR(exp) == -EAGAIN)
174 goto out;
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
190 /* Set user creds for this exportpoint */
191 error = nfsd_setuser(rqstp, exp);
192 if (error) {
193 error = nfserrno(error);
194 goto out;
195 }
196
197 /*
198 * Look up the dentry using the NFS file handle.
199 */
200 error = nfserr_stale;
201 if (rqstp->rq_vers > 2)
202 error = nfserr_badhandle;
203
204 if (fh->fh_version != 1) {
205 tfh[0] = fh->ofh_ino;
206 tfh[1] = fh->ofh_generation;
207 tfh[2] = fh->ofh_dirino;
208 datap = tfh;
209 data_left = 3;
210 if (fh->ofh_dirino == 0)
211 fileid_type = 1;
212 else
213 fileid_type = 2;
214 } else
215 fileid_type = fh->fh_fileid_type;
216
217 if (fileid_type == 0)
218 dentry = dget(exp->ex_dentry);
219 else {
220 struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
221 dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
222 datap, data_left,
223 fileid_type,
224 nfsd_acceptable, exp);
225 }
226 if (dentry == NULL)
227 goto out;
228 if (IS_ERR(dentry)) {
229 if (PTR_ERR(dentry) != -EINVAL)
230 error = nfserrno(PTR_ERR(dentry));
231 goto out;
232 }
233#ifdef NFSD_PARANOIA
234 if (S_ISDIR(dentry->d_inode->i_mode) &&
235 (dentry->d_flags & DCACHE_DISCONNECTED)) {
236 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
237 dentry->d_parent->d_name.name, dentry->d_name.name);
238 }
239#endif
240
241 fhp->fh_dentry = dentry;
242 fhp->fh_export = exp;
243 nfsd_nr_verified++;
244 } else {
245 /* just rechecking permissions
246 * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
247 */
248 dprintk("nfsd: fh_verify - just checking\n");
249 dentry = fhp->fh_dentry;
250 exp = fhp->fh_export;
251 }
252 cache_get(&exp->h);
253
254 error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
255 if (error)
256 goto out;
257
258 /* Finally, check access permissions. */
259 error = nfsd_permission(exp, dentry, access);
260
261#ifdef NFSD_PARANOIA_EXTREME
262 if (error) {
263 printk("fh_verify: %s/%s permission failure, acc=%x, error=%d\n",
264 dentry->d_parent->d_name.name, dentry->d_name.name, access, (error >> 24));
265 }
266#endif
267out:
268 if (exp && !IS_ERR(exp))
269 exp_put(exp);
270 if (error == nfserr_stale)
271 nfsdstats.fh_stale++;
272 return error;
273}
274
275
276/*
277 * Compose a file handle for an NFS reply.
278 *
279 * Note that when first composed, the dentry may not yet have
280 * an inode. In this case a call to fh_update should be made
281 * before the fh goes out on the wire ...
282 */
283static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
284 __u32 *datap, int *maxsize)
285{
286 struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
287
288 if (dentry == exp->ex_dentry) {
289 *maxsize = 0;
290 return 0;
291 }
292
293 return CALL(nop,encode_fh)(dentry, datap, maxsize,
294 !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
295}
296
297/*
298 * for composing old style file handles
299 */
300static inline void _fh_update_old(struct dentry *dentry,
301 struct svc_export *exp,
302 struct knfsd_fh *fh)
303{
304 fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
305 fh->ofh_generation = dentry->d_inode->i_generation;
306 if (S_ISDIR(dentry->d_inode->i_mode) ||
307 (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
308 fh->ofh_dirino = 0;
309}
310
311int
312fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry, struct svc_fh *ref_fh)
313{
314 /* ref_fh is a reference file handle.
315 * if it is non-null, then we should compose a filehandle which is
316 * of the same version, where possible.
317 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
318 * Then create a 32byte filehandle using nfs_fhbase_old
319 *
320 */
321
322 u8 ref_fh_version = 0;
323 u8 ref_fh_fsid_type = 0;
324 struct inode * inode = dentry->d_inode;
325 struct dentry *parent = dentry->d_parent;
326 __u32 *datap;
327 dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
328
329 dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
330 MAJOR(ex_dev), MINOR(ex_dev),
331 (long) exp->ex_dentry->d_inode->i_ino,
332 parent->d_name.name, dentry->d_name.name,
333 (inode ? inode->i_ino : 0));
334
335 if (ref_fh) {
336 ref_fh_version = ref_fh->fh_handle.fh_version;
337 if (ref_fh_version == 0xca)
338 ref_fh_fsid_type = 0;
339 else
340 ref_fh_fsid_type = ref_fh->fh_handle.fh_fsid_type;
341 if (ref_fh_fsid_type > 3)
342 ref_fh_fsid_type = 0;
343
344 /* make sure ref_fh type works for given export */
345 if (ref_fh_fsid_type == 1 &&
346 !(exp->ex_flags & NFSEXP_FSID)) {
347 /* if we don't have an fsid, we cannot provide one... */
348 ref_fh_fsid_type = 0;
349 }
350 } else if (exp->ex_flags & NFSEXP_FSID)
351 ref_fh_fsid_type = 1;
352
353 if (!old_valid_dev(ex_dev) && ref_fh_fsid_type == 0) {
354 /* for newer device numbers, we must use a newer fsid format */
355 ref_fh_version = 1;
356 ref_fh_fsid_type = 3;
357 }
358 if (old_valid_dev(ex_dev) &&
359 (ref_fh_fsid_type == 2 || ref_fh_fsid_type == 3))
360 /* must use type1 for smaller device numbers */
361 ref_fh_fsid_type = 0;
362
363 if (ref_fh == fhp)
364 fh_put(ref_fh);
365
366 if (fhp->fh_locked || fhp->fh_dentry) {
367 printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
368 parent->d_name.name, dentry->d_name.name);
369 }
370 if (fhp->fh_maxsize < NFS_FHSIZE)
371 printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
372 fhp->fh_maxsize, parent->d_name.name, dentry->d_name.name);
373
374 fhp->fh_dentry = dget(dentry); /* our internal copy */
375 fhp->fh_export = exp;
376 cache_get(&exp->h);
377
378 if (ref_fh_version == 0xca) {
379 /* old style filehandle please */
380 memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
381 fhp->fh_handle.fh_size = NFS_FHSIZE;
382 fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
383 fhp->fh_handle.ofh_dev = old_encode_dev(ex_dev);
384 fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
385 fhp->fh_handle.ofh_xino = ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
386 fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
387 if (inode)
388 _fh_update_old(dentry, exp, &fhp->fh_handle);
389 } else {
390 int len;
391 fhp->fh_handle.fh_version = 1;
392 fhp->fh_handle.fh_auth_type = 0;
393 datap = fhp->fh_handle.fh_auth+0;
394 fhp->fh_handle.fh_fsid_type = ref_fh_fsid_type;
395 switch (ref_fh_fsid_type) {
396 case 0:
397 /*
398 * fsid_type 0:
399 * 2byte major, 2byte minor, 4byte inode
400 */
401 mk_fsid_v0(datap, ex_dev,
402 exp->ex_dentry->d_inode->i_ino);
403 break;
404 case 1:
405 /* fsid_type 1 == 4 bytes filesystem id */
406 mk_fsid_v1(datap, exp->ex_fsid);
407 break;
408 case 2:
409 /*
410 * fsid_type 2:
411 * 4byte major, 4byte minor, 4byte inode
412 */
413 mk_fsid_v2(datap, ex_dev,
414 exp->ex_dentry->d_inode->i_ino);
415 break;
416 case 3:
417 /*
418 * fsid_type 3:
419 * 4byte devicenumber, 4byte inode
420 */
421 mk_fsid_v3(datap, ex_dev,
422 exp->ex_dentry->d_inode->i_ino);
423 break;
424 }
425 len = key_len(ref_fh_fsid_type);
426 datap += len/4;
427 fhp->fh_handle.fh_size = 4 + len;
428
429 if (inode) {
430 int size = (fhp->fh_maxsize-len-4)/4;
431 fhp->fh_handle.fh_fileid_type =
432 _fh_update(dentry, exp, datap, &size);
433 fhp->fh_handle.fh_size += size*4;
434 }
435 if (fhp->fh_handle.fh_fileid_type == 255)
436 return nfserr_opnotsupp;
437 }
438
439 nfsd_nr_verified++;
440 return 0;
441}
442
443/*
444 * Update file handle information after changing a dentry.
445 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
446 */
447int
448fh_update(struct svc_fh *fhp)
449{
450 struct dentry *dentry;
451 __u32 *datap;
452
453 if (!fhp->fh_dentry)
454 goto out_bad;
455
456 dentry = fhp->fh_dentry;
457 if (!dentry->d_inode)
458 goto out_negative;
459 if (fhp->fh_handle.fh_version != 1) {
460 _fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
461 } else {
462 int size;
463 if (fhp->fh_handle.fh_fileid_type != 0)
464 goto out_uptodate;
465 datap = fhp->fh_handle.fh_auth+
466 fhp->fh_handle.fh_size/4 -1;
467 size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
468 fhp->fh_handle.fh_fileid_type =
469 _fh_update(dentry, fhp->fh_export, datap, &size);
470 fhp->fh_handle.fh_size += size*4;
471 if (fhp->fh_handle.fh_fileid_type == 255)
472 return nfserr_opnotsupp;
473 }
474out:
475 return 0;
476
477out_bad:
478 printk(KERN_ERR "fh_update: fh not verified!\n");
479 goto out;
480out_negative:
481 printk(KERN_ERR "fh_update: %s/%s still negative!\n",
482 dentry->d_parent->d_name.name, dentry->d_name.name);
483 goto out;
484out_uptodate:
485 printk(KERN_ERR "fh_update: %s/%s already up-to-date!\n",
486 dentry->d_parent->d_name.name, dentry->d_name.name);
487 goto out;
488}
489
490/*
491 * Release a file handle.
492 */
493void
494fh_put(struct svc_fh *fhp)
495{
496 struct dentry * dentry = fhp->fh_dentry;
497 struct svc_export * exp = fhp->fh_export;
498 if (dentry) {
499 fh_unlock(fhp);
500 fhp->fh_dentry = NULL;
501 dput(dentry);
502#ifdef CONFIG_NFSD_V3
503 fhp->fh_pre_saved = 0;
504 fhp->fh_post_saved = 0;
505#endif
506 nfsd_nr_put++;
507 }
508 if (exp) {
509 svc_export_put(&exp->h, &svc_export_cache);
510 fhp->fh_export = NULL;
511 }
512 return;
513}
514
515/*
516 * Shorthand for dprintk()'s
517 */
518char * SVCFH_fmt(struct svc_fh *fhp)
519{
520 struct knfsd_fh *fh = &fhp->fh_handle;
521
522 static char buf[80];
523 sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
524 fh->fh_size,
525 fh->fh_base.fh_pad[0],
526 fh->fh_base.fh_pad[1],
527 fh->fh_base.fh_pad[2],
528 fh->fh_base.fh_pad[3],
529 fh->fh_base.fh_pad[4],
530 fh->fh_base.fh_pad[5]);
531 return buf;
532}