summaryrefslogtreecommitdiff
path: root/fs/nfsd/nfsfh.c
blob: 4f712e970584939847ed8287ffa0e379cea177e4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
/*
 * linux/fs/nfsd/nfsfh.c
 *
 * NFS server file handle treatment.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 * Portions Copyright (C) 1999 G. Allen Morris III <gam3@acm.org>
 * Extensive rewrite by Neil Brown <neilb@cse.unsw.edu.au> Southern-Spring 1999
 * ... and again Southern-Winter 2001 to support export_operations
 */

#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/unistd.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/dcache.h>
#include <linux/exportfs.h>
#include <linux/mount.h>

#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcauth_gss.h>
#include <linux/nfsd/nfsd.h>

#define NFSDDBG_FACILITY		NFSDDBG_FH


static int nfsd_nr_verified;
static int nfsd_nr_put;

/*
 * our acceptability function.
 * if NOSUBTREECHECK, accept anything
 * if not, require that we can walk up to exp->ex_dentry
 * doing some checks on the 'x' bits
 */
static int nfsd_acceptable(void *expv, struct dentry *dentry)
{
	struct svc_export *exp = expv;
	int rv;
	struct dentry *tdentry;
	struct dentry *parent;

	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
		return 1;

	tdentry = dget(dentry);
	while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
		/* make sure parents give x permission to user */
		int err;
		parent = dget_parent(tdentry);
		err = permission(parent->d_inode, MAY_EXEC, NULL);
		if (err < 0) {
			dput(parent);
			break;
		}
		dput(tdentry);
		tdentry = parent;
	}
	if (tdentry != exp->ex_dentry)
		dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
	rv = (tdentry == exp->ex_dentry);
	dput(tdentry);
	return rv;
}

/* Type check. The correct error return for type mismatches does not seem to be
 * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
 * comment in the NFSv3 spec says this is incorrect (implementation notes for
 * the write call).
 */
static inline __be32
nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
{
	/* Type can be negative when creating hardlinks - not to a dir */
	if (type > 0 && (mode & S_IFMT) != type) {
		if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
			return nfserr_symlink;
		else if (type == S_IFDIR)
			return nfserr_notdir;
		else if ((mode & S_IFMT) == S_IFDIR)
			return nfserr_isdir;
		else
			return nfserr_inval;
	}
	if (type < 0 && (mode & S_IFMT) == -type) {
		if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
			return nfserr_symlink;
		else if (type == -S_IFDIR)
			return nfserr_isdir;
		else
			return nfserr_notdir;
	}
	return 0;
}

/*
 * Perform sanity checks on the dentry in a client's file handle.
 *
 * Note that the file handle dentry may need to be freed even after
 * an error return.
 *
 * This is only called at the start of an nfsproc call, so fhp points to
 * a svc_fh which is all 0 except for the over-the-wire file handle.
 */
__be32
fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
{
	struct knfsd_fh	*fh = &fhp->fh_handle;
	struct svc_export *exp = NULL;
	struct dentry	*dentry;
	__be32		error = 0;

	dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));

	if (!fhp->fh_dentry) {
		struct fid *fid = NULL, sfid;
		int fileid_type;
		int data_left = fh->fh_size/4;

		error = nfserr_stale;
		if (rqstp->rq_vers > 2)
			error = nfserr_badhandle;
		if (rqstp->rq_vers == 4 && fh->fh_size == 0)
			return nfserr_nofilehandle;

		if (fh->fh_version == 1) {
			int len;
			if (--data_left<0) goto out;
			switch (fh->fh_auth_type) {
			case 0: break;
			default: goto out;
			}
			len = key_len(fh->fh_fsid_type) / 4;
			if (len == 0) goto out;
			if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
				/* deprecated, convert to type 3 */
				len = key_len(FSID_ENCODE_DEV)/4;
				fh->fh_fsid_type = FSID_ENCODE_DEV;
				fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
				fh->fh_fsid[1] = fh->fh_fsid[2];
			}
			if ((data_left -= len)<0) goto out;
			exp = rqst_exp_find(rqstp, fh->fh_fsid_type,
					    fh->fh_auth);
			fid = (struct fid *)(fh->fh_auth + len);
		} else {
			__u32 tfh[2];
			dev_t xdev;
			ino_t xino;
			if (fh->fh_size != NFS_FHSIZE)
				goto out;
			/* assume old filehandle format */
			xdev = old_decode_dev(fh->ofh_xdev);
			xino = u32_to_ino_t(fh->ofh_xino);
			mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
			exp = rqst_exp_find(rqstp, FSID_DEV, tfh);
		}

		error = nfserr_stale;
		if (PTR_ERR(exp) == -ENOENT)
			goto out;

		if (IS_ERR(exp)) {
			error = nfserrno(PTR_ERR(exp));
			goto out;
		}

		/* Check if the request originated from a secure port. */
		error = nfserr_perm;
		if (!rqstp->rq_secure && EX_SECURE(exp)) {
			char buf[RPC_MAX_ADDRBUFLEN];
			printk(KERN_WARNING
			       "nfsd: request from insecure port %s!\n",
			       svc_print_addr(rqstp, buf, sizeof(buf)));
			goto out;
		}

		/* Set user creds for this exportpoint */
		error = nfserrno(nfsd_setuser(rqstp, exp));
		if (error)
			goto out;

		/*
		 * Look up the dentry using the NFS file handle.
		 */
		error = nfserr_stale;
		if (rqstp->rq_vers > 2)
			error = nfserr_badhandle;

		if (fh->fh_version != 1) {
			sfid.i32.ino = fh->ofh_ino;
			sfid.i32.gen = fh->ofh_generation;
			sfid.i32.parent_ino = fh->ofh_dirino;
			fid = &sfid;
			data_left = 3;
			if (fh->ofh_dirino == 0)
				fileid_type = FILEID_INO32_GEN;
			else
				fileid_type = FILEID_INO32_GEN_PARENT;
		} else
			fileid_type = fh->fh_fileid_type;

		if (fileid_type == FILEID_ROOT)
			dentry = dget(exp->ex_dentry);
		else {
			dentry = exportfs_decode_fh(exp->ex_mnt, fid,
					data_left, fileid_type,
					nfsd_acceptable, exp);
		}
		if (dentry == NULL)
			goto out;
		if (IS_ERR(dentry)) {
			if (PTR_ERR(dentry) != -EINVAL)
				error = nfserrno(PTR_ERR(dentry));
			goto out;
		}

		if (S_ISDIR(dentry->d_inode->i_mode) &&
		    (dentry->d_flags & DCACHE_DISCONNECTED)) {
			printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
			       dentry->d_parent->d_name.name, dentry->d_name.name);
		}

		fhp->fh_dentry = dentry;
		fhp->fh_export = exp;
		nfsd_nr_verified++;
	} else {
		/* just rechecking permissions
		 * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
		 */
		dprintk("nfsd: fh_verify - just checking\n");
		dentry = fhp->fh_dentry;
		exp = fhp->fh_export;
		/* Set user creds for this exportpoint; necessary even
		 * in the "just checking" case because this may be a
		 * filehandle that was created by fh_compose, and that
		 * is about to be used in another nfsv4 compound
		 * operation */
		error = nfserrno(nfsd_setuser(rqstp, exp));
		if (error)
			goto out;
	}
	cache_get(&exp->h);


	error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
	if (error)
		goto out;

	if (!(access & MAY_LOCK)) {
		/*
		 * pseudoflavor restrictions are not enforced on NLM,
		 * which clients virtually always use auth_sys for,
		 * even while using RPCSEC_GSS for NFS.
		 */
		error = check_nfsd_access(exp, rqstp);
		if (error)
			goto out;
	}

	/* Finally, check access permissions. */
	error = nfsd_permission(rqstp, exp, dentry, access);

	if (error) {
		dprintk("fh_verify: %s/%s permission failure, "
			"acc=%x, error=%d\n",
			dentry->d_parent->d_name.name,
			dentry->d_name.name,
			access, ntohl(error));
	}
out:
	if (exp && !IS_ERR(exp))
		exp_put(exp);
	if (error == nfserr_stale)
		nfsdstats.fh_stale++;
	return error;
}


/*
 * Compose a file handle for an NFS reply.
 *
 * Note that when first composed, the dentry may not yet have
 * an inode.  In this case a call to fh_update should be made
 * before the fh goes out on the wire ...
 */
static void _fh_update(struct svc_fh *fhp, struct svc_export *exp,
		struct dentry *dentry)
{
	if (dentry != exp->ex_dentry) {
		struct fid *fid = (struct fid *)
			(fhp->fh_handle.fh_auth + fhp->fh_handle.fh_size/4 - 1);
		int maxsize = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
		int subtreecheck = !(exp->ex_flags & NFSEXP_NOSUBTREECHECK);

		fhp->fh_handle.fh_fileid_type =
			exportfs_encode_fh(dentry, fid, &maxsize, subtreecheck);
		fhp->fh_handle.fh_size += maxsize * 4;
	} else {
		fhp->fh_handle.fh_fileid_type = FILEID_ROOT;
	}
}

/*
 * for composing old style file handles
 */
static inline void _fh_update_old(struct dentry *dentry,
				  struct svc_export *exp,
				  struct knfsd_fh *fh)
{
	fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
	fh->ofh_generation = dentry->d_inode->i_generation;
	if (S_ISDIR(dentry->d_inode->i_mode) ||
	    (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
		fh->ofh_dirino = 0;
}

__be32
fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
	   struct svc_fh *ref_fh)
{
	/* ref_fh is a reference file handle.
	 * if it is non-null and for the same filesystem, then we should compose
	 * a filehandle which is of the same version, where possible.
	 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
	 * Then create a 32byte filehandle using nfs_fhbase_old
	 *
	 */

	u8 version;
	u8 fsid_type = 0;
	struct inode * inode = dentry->d_inode;
	struct dentry *parent = dentry->d_parent;
	__u32 *datap;
	dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
	int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);

	dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
		MAJOR(ex_dev), MINOR(ex_dev),
		(long) exp->ex_dentry->d_inode->i_ino,
		parent->d_name.name, dentry->d_name.name,
		(inode ? inode->i_ino : 0));

	/* Choose filehandle version and fsid type based on
	 * the reference filehandle (if it is in the same export)
	 * or the export options.
	 */
 retry:
	version = 1;
	if (ref_fh && ref_fh->fh_export == exp) {
		version = ref_fh->fh_handle.fh_version;
		fsid_type = ref_fh->fh_handle.fh_fsid_type;

		if (ref_fh == fhp)
			fh_put(ref_fh);
		ref_fh = NULL;

		switch (version) {
		case 0xca:
			fsid_type = FSID_DEV;
			break;
		case 1:
			break;
		default:
			goto retry;
		}

		/* Need to check that this type works for this
		 * export point.  As the fsid -> filesystem mapping
		 * was guided by user-space, there is no guarantee
		 * that the filesystem actually supports that fsid
		 * type. If it doesn't we loop around again without
		 * ref_fh set.
		 */
		switch(fsid_type) {
		case FSID_DEV:
			if (!old_valid_dev(ex_dev))
				goto retry;
			/* FALL THROUGH */
		case FSID_MAJOR_MINOR:
		case FSID_ENCODE_DEV:
			if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
			      & FS_REQUIRES_DEV))
				goto retry;
			break;
		case FSID_NUM:
			if (! (exp->ex_flags & NFSEXP_FSID))
				goto retry;
			break;
		case FSID_UUID8:
		case FSID_UUID16:
			if (!root_export)
				goto retry;
			/* fall through */
		case FSID_UUID4_INUM:
		case FSID_UUID16_INUM:
			if (exp->ex_uuid == NULL)
				goto retry;
			break;
		}
	} else if (exp->ex_uuid) {
		if (fhp->fh_maxsize >= 64) {
			if (root_export)
				fsid_type = FSID_UUID16;
			else
				fsid_type = FSID_UUID16_INUM;
		} else {
			if (root_export)
				fsid_type = FSID_UUID8;
			else
				fsid_type = FSID_UUID4_INUM;
		}
	} else if (exp->ex_flags & NFSEXP_FSID)
		fsid_type = FSID_NUM;
	else if (!old_valid_dev(ex_dev))
		/* for newer device numbers, we must use a newer fsid format */
		fsid_type = FSID_ENCODE_DEV;
	else
		fsid_type = FSID_DEV;

	if (ref_fh == fhp)
		fh_put(ref_fh);

	if (fhp->fh_locked || fhp->fh_dentry) {
		printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
		       parent->d_name.name, dentry->d_name.name);
	}
	if (fhp->fh_maxsize < NFS_FHSIZE)
		printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
		       fhp->fh_maxsize,
		       parent->d_name.name, dentry->d_name.name);

	fhp->fh_dentry = dget(dentry); /* our internal copy */
	fhp->fh_export = exp;
	cache_get(&exp->h);

	if (version == 0xca) {
		/* old style filehandle please */
		memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
		fhp->fh_handle.fh_size = NFS_FHSIZE;
		fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
		fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
		fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
		fhp->fh_handle.ofh_xino =
			ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
		fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
		if (inode)
			_fh_update_old(dentry, exp, &fhp->fh_handle);
	} else {
		int len;
		fhp->fh_handle.fh_version = 1;
		fhp->fh_handle.fh_auth_type = 0;
		datap = fhp->fh_handle.fh_auth+0;
		fhp->fh_handle.fh_fsid_type = fsid_type;
		mk_fsid(fsid_type, datap, ex_dev,
			exp->ex_dentry->d_inode->i_ino,
			exp->ex_fsid, exp->ex_uuid);

		len = key_len(fsid_type);
		datap += len/4;
		fhp->fh_handle.fh_size = 4 + len;

		if (inode)
			_fh_update(fhp, exp, dentry);
		if (fhp->fh_handle.fh_fileid_type == 255)
			return nfserr_opnotsupp;
	}

	nfsd_nr_verified++;
	return 0;
}

/*
 * Update file handle information after changing a dentry.
 * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
 */
__be32
fh_update(struct svc_fh *fhp)
{
	struct dentry *dentry;

	if (!fhp->fh_dentry)
		goto out_bad;

	dentry = fhp->fh_dentry;
	if (!dentry->d_inode)
		goto out_negative;
	if (fhp->fh_handle.fh_version != 1) {
		_fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
	} else {
		if (fhp->fh_handle.fh_fileid_type != FILEID_ROOT)
			goto out;

		_fh_update(fhp, fhp->fh_export, dentry);
		if (fhp->fh_handle.fh_fileid_type == 255)
			return nfserr_opnotsupp;
	}
out:
	return 0;

out_bad:
	printk(KERN_ERR "fh_update: fh not verified!\n");
	goto out;
out_negative:
	printk(KERN_ERR "fh_update: %s/%s still negative!\n",
		dentry->d_parent->d_name.name, dentry->d_name.name);
	goto out;
}

/*
 * Release a file handle.
 */
void
fh_put(struct svc_fh *fhp)
{
	struct dentry * dentry = fhp->fh_dentry;
	struct svc_export * exp = fhp->fh_export;
	if (dentry) {
		fh_unlock(fhp);
		fhp->fh_dentry = NULL;
		dput(dentry);
#ifdef CONFIG_NFSD_V3
		fhp->fh_pre_saved = 0;
		fhp->fh_post_saved = 0;
#endif
		nfsd_nr_put++;
	}
	if (exp) {
		cache_put(&exp->h, &svc_export_cache);
		fhp->fh_export = NULL;
	}
	return;
}

/*
 * Shorthand for dprintk()'s
 */
char * SVCFH_fmt(struct svc_fh *fhp)
{
	struct knfsd_fh *fh = &fhp->fh_handle;

	static char buf[80];
	sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
		fh->fh_size,
		fh->fh_base.fh_pad[0],
		fh->fh_base.fh_pad[1],
		fh->fh_base.fh_pad[2],
		fh->fh_base.fh_pad[3],
		fh->fh_base.fh_pad[4],
		fh->fh_base.fh_pad[5]);
	return buf;
}

enum fsid_source fsid_source(struct svc_fh *fhp)
{
	if (fhp->fh_handle.fh_version != 1)
		return FSIDSOURCE_DEV;
	switch(fhp->fh_handle.fh_fsid_type) {
	case FSID_DEV:
	case FSID_ENCODE_DEV:
	case FSID_MAJOR_MINOR:
		if (fhp->fh_export->ex_dentry->d_inode->i_sb->s_type->fs_flags
		    & FS_REQUIRES_DEV)
			return FSIDSOURCE_DEV;
		break;
	case FSID_NUM:
		if (fhp->fh_export->ex_flags & NFSEXP_FSID)
			return FSIDSOURCE_FSID;
		break;
	default:
		break;
	}
	/* either a UUID type filehandle, or the filehandle doesn't
	 * match the export.
	 */
	if (fhp->fh_export->ex_flags & NFSEXP_FSID)
		return FSIDSOURCE_FSID;
	if (fhp->fh_export->ex_uuid)
		return FSIDSOURCE_UUID;
	return FSIDSOURCE_DEV;
}