xref: /openbmc/linux/fs/nfsd/nfsfh.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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/slab.h>
13 #include <linux/fs.h>
14 #include <linux/unistd.h>
15 #include <linux/string.h>
16 #include <linux/stat.h>
17 #include <linux/dcache.h>
18 #include <linux/mount.h>
19 
20 #include <linux/sunrpc/clnt.h>
21 #include <linux/sunrpc/svc.h>
22 #include <linux/nfsd/nfsd.h>
23 
24 #define NFSDDBG_FACILITY		NFSDDBG_FH
25 
26 
27 static int nfsd_nr_verified;
28 static int nfsd_nr_put;
29 
30 extern struct export_operations export_op_default;
31 
32 #define	CALL(ops,fun) ((ops->fun)?(ops->fun):export_op_default.fun)
33 
34 /*
35  * our acceptability function.
36  * if NOSUBTREECHECK, accept anything
37  * if not, require that we can walk up to exp->ex_dentry
38  * doing some checks on the 'x' bits
39  */
40 static int nfsd_acceptable(void *expv, struct dentry *dentry)
41 {
42 	struct svc_export *exp = expv;
43 	int rv;
44 	struct dentry *tdentry;
45 	struct dentry *parent;
46 
47 	if (exp->ex_flags & NFSEXP_NOSUBTREECHECK)
48 		return 1;
49 
50 	tdentry = dget(dentry);
51 	while (tdentry != exp->ex_dentry && ! IS_ROOT(tdentry)) {
52 		/* make sure parents give x permission to user */
53 		int err;
54 		parent = dget_parent(tdentry);
55 		err = permission(parent->d_inode, MAY_EXEC, NULL);
56 		if (err < 0) {
57 			dput(parent);
58 			break;
59 		}
60 		dput(tdentry);
61 		tdentry = parent;
62 	}
63 	if (tdentry != exp->ex_dentry)
64 		dprintk("nfsd_acceptable failed at %p %s\n", tdentry, tdentry->d_name.name);
65 	rv = (tdentry == exp->ex_dentry);
66 	dput(tdentry);
67 	return rv;
68 }
69 
70 /* Type check. The correct error return for type mismatches does not seem to be
71  * generally agreed upon. SunOS seems to use EISDIR if file isn't S_IFREG; a
72  * comment in the NFSv3 spec says this is incorrect (implementation notes for
73  * the write call).
74  */
75 static inline __be32
76 nfsd_mode_check(struct svc_rqst *rqstp, umode_t mode, int type)
77 {
78 	/* Type can be negative when creating hardlinks - not to a dir */
79 	if (type > 0 && (mode & S_IFMT) != type) {
80 		if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
81 			return nfserr_symlink;
82 		else if (type == S_IFDIR)
83 			return nfserr_notdir;
84 		else if ((mode & S_IFMT) == S_IFDIR)
85 			return nfserr_isdir;
86 		else
87 			return nfserr_inval;
88 	}
89 	if (type < 0 && (mode & S_IFMT) == -type) {
90 		if (rqstp->rq_vers == 4 && (mode & S_IFMT) == S_IFLNK)
91 			return nfserr_symlink;
92 		else if (type == -S_IFDIR)
93 			return nfserr_isdir;
94 		else
95 			return nfserr_notdir;
96 	}
97 	return 0;
98 }
99 
100 /*
101  * Perform sanity checks on the dentry in a client's file handle.
102  *
103  * Note that the file handle dentry may need to be freed even after
104  * an error return.
105  *
106  * This is only called at the start of an nfsproc call, so fhp points to
107  * a svc_fh which is all 0 except for the over-the-wire file handle.
108  */
109 __be32
110 fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access)
111 {
112 	struct knfsd_fh	*fh = &fhp->fh_handle;
113 	struct svc_export *exp = NULL;
114 	struct dentry	*dentry;
115 	__be32		error = 0;
116 
117 	dprintk("nfsd: fh_verify(%s)\n", SVCFH_fmt(fhp));
118 
119 	if (!fhp->fh_dentry) {
120 		__u32 *datap=NULL;
121 		__u32 tfh[3];		/* filehandle fragment for oldstyle filehandles */
122 		int fileid_type;
123 		int data_left = fh->fh_size/4;
124 
125 		error = nfserr_stale;
126 		if (rqstp->rq_client == NULL)
127 			goto out;
128 		if (rqstp->rq_vers > 2)
129 			error = nfserr_badhandle;
130 		if (rqstp->rq_vers == 4 && fh->fh_size == 0)
131 			return nfserr_nofilehandle;
132 
133 		if (fh->fh_version == 1) {
134 			int len;
135 			datap = fh->fh_auth;
136 			if (--data_left<0) goto out;
137 			switch (fh->fh_auth_type) {
138 			case 0: break;
139 			default: goto out;
140 			}
141 			len = key_len(fh->fh_fsid_type) / 4;
142 			if (len == 0) goto out;
143 			if  (fh->fh_fsid_type == FSID_MAJOR_MINOR) {
144 				/* deprecated, convert to type 3 */
145 				len = key_len(FSID_ENCODE_DEV)/4;
146 				fh->fh_fsid_type = FSID_ENCODE_DEV;
147 				fh->fh_fsid[0] = new_encode_dev(MKDEV(ntohl(fh->fh_fsid[0]), ntohl(fh->fh_fsid[1])));
148 				fh->fh_fsid[1] = fh->fh_fsid[2];
149 			}
150 			if ((data_left -= len)<0) goto out;
151 			exp = exp_find(rqstp->rq_client, fh->fh_fsid_type, datap, &rqstp->rq_chandle);
152 			datap += len;
153 		} else {
154 			dev_t xdev;
155 			ino_t xino;
156 			if (fh->fh_size != NFS_FHSIZE)
157 				goto out;
158 			/* assume old filehandle format */
159 			xdev = old_decode_dev(fh->ofh_xdev);
160 			xino = u32_to_ino_t(fh->ofh_xino);
161 			mk_fsid(FSID_DEV, tfh, xdev, xino, 0, NULL);
162 			exp = exp_find(rqstp->rq_client, FSID_DEV, tfh,
163 				       &rqstp->rq_chandle);
164 		}
165 
166 		if (IS_ERR(exp) && (PTR_ERR(exp) == -EAGAIN
167 				|| PTR_ERR(exp) == -ETIMEDOUT)) {
168 			error = nfserrno(PTR_ERR(exp));
169 			goto out;
170 		}
171 
172 		error = nfserr_stale;
173 		if (!exp || IS_ERR(exp))
174 			goto out;
175 
176 		/* Check if the request originated from a secure port. */
177 		error = nfserr_perm;
178 		if (!rqstp->rq_secure && EX_SECURE(exp)) {
179 			char buf[RPC_MAX_ADDRBUFLEN];
180 			printk(KERN_WARNING
181 			       "nfsd: request from insecure port %s!\n",
182 			       svc_print_addr(rqstp, buf, sizeof(buf)));
183 			goto out;
184 		}
185 
186 		/* Set user creds for this exportpoint */
187 		error = nfserrno(nfsd_setuser(rqstp, exp));
188 		if (error)
189 			goto out;
190 
191 		/*
192 		 * Look up the dentry using the NFS file handle.
193 		 */
194 		error = nfserr_stale;
195 		if (rqstp->rq_vers > 2)
196 			error = nfserr_badhandle;
197 
198 		if (fh->fh_version != 1) {
199 			tfh[0] = fh->ofh_ino;
200 			tfh[1] = fh->ofh_generation;
201 			tfh[2] = fh->ofh_dirino;
202 			datap = tfh;
203 			data_left = 3;
204 			if (fh->ofh_dirino == 0)
205 				fileid_type = 1;
206 			else
207 				fileid_type = 2;
208 		} else
209 			fileid_type = fh->fh_fileid_type;
210 
211 		if (fileid_type == 0)
212 			dentry = dget(exp->ex_dentry);
213 		else {
214 			struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
215 			dentry = CALL(nop,decode_fh)(exp->ex_mnt->mnt_sb,
216 						     datap, data_left,
217 						     fileid_type,
218 						     nfsd_acceptable, exp);
219 		}
220 		if (dentry == NULL)
221 			goto out;
222 		if (IS_ERR(dentry)) {
223 			if (PTR_ERR(dentry) != -EINVAL)
224 				error = nfserrno(PTR_ERR(dentry));
225 			goto out;
226 		}
227 
228 		if (S_ISDIR(dentry->d_inode->i_mode) &&
229 		    (dentry->d_flags & DCACHE_DISCONNECTED)) {
230 			printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",
231 			       dentry->d_parent->d_name.name, dentry->d_name.name);
232 		}
233 
234 		fhp->fh_dentry = dentry;
235 		fhp->fh_export = exp;
236 		nfsd_nr_verified++;
237 	} else {
238 		/* just rechecking permissions
239 		 * (e.g. nfsproc_create calls fh_verify, then nfsd_create does as well)
240 		 */
241 		dprintk("nfsd: fh_verify - just checking\n");
242 		dentry = fhp->fh_dentry;
243 		exp = fhp->fh_export;
244 		/* Set user creds for this exportpoint; necessary even
245 		 * in the "just checking" case because this may be a
246 		 * filehandle that was created by fh_compose, and that
247 		 * is about to be used in another nfsv4 compound
248 		 * operation */
249 		error = nfserrno(nfsd_setuser(rqstp, exp));
250 		if (error)
251 			goto out;
252 	}
253 	cache_get(&exp->h);
254 
255 
256 	error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
257 	if (error)
258 		goto out;
259 
260 	/* Finally, check access permissions. */
261 	error = nfsd_permission(exp, dentry, access);
262 
263 	if (error) {
264 		dprintk("fh_verify: %s/%s permission failure, "
265 			"acc=%x, error=%d\n",
266 			dentry->d_parent->d_name.name,
267 			dentry->d_name.name,
268 			access, ntohl(error));
269 	}
270 out:
271 	if (exp && !IS_ERR(exp))
272 		exp_put(exp);
273 	if (error == nfserr_stale)
274 		nfsdstats.fh_stale++;
275 	return error;
276 }
277 
278 
279 /*
280  * Compose a file handle for an NFS reply.
281  *
282  * Note that when first composed, the dentry may not yet have
283  * an inode.  In this case a call to fh_update should be made
284  * before the fh goes out on the wire ...
285  */
286 static inline int _fh_update(struct dentry *dentry, struct svc_export *exp,
287 			     __u32 *datap, int *maxsize)
288 {
289 	struct export_operations *nop = exp->ex_mnt->mnt_sb->s_export_op;
290 
291 	if (dentry == exp->ex_dentry) {
292 		*maxsize = 0;
293 		return 0;
294 	}
295 
296 	return CALL(nop,encode_fh)(dentry, datap, maxsize,
297 			  !(exp->ex_flags&NFSEXP_NOSUBTREECHECK));
298 }
299 
300 /*
301  * for composing old style file handles
302  */
303 static inline void _fh_update_old(struct dentry *dentry,
304 				  struct svc_export *exp,
305 				  struct knfsd_fh *fh)
306 {
307 	fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
308 	fh->ofh_generation = dentry->d_inode->i_generation;
309 	if (S_ISDIR(dentry->d_inode->i_mode) ||
310 	    (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
311 		fh->ofh_dirino = 0;
312 }
313 
314 __be32
315 fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
316 	   struct svc_fh *ref_fh)
317 {
318 	/* ref_fh is a reference file handle.
319 	 * if it is non-null and for the same filesystem, then we should compose
320 	 * a filehandle which is of the same version, where possible.
321 	 * Currently, that means that if ref_fh->fh_handle.fh_version == 0xca
322 	 * Then create a 32byte filehandle using nfs_fhbase_old
323 	 *
324 	 */
325 
326 	u8 version;
327 	u8 fsid_type = 0;
328 	struct inode * inode = dentry->d_inode;
329 	struct dentry *parent = dentry->d_parent;
330 	__u32 *datap;
331 	dev_t ex_dev = exp->ex_dentry->d_inode->i_sb->s_dev;
332 	int root_export = (exp->ex_dentry == exp->ex_dentry->d_sb->s_root);
333 
334 	dprintk("nfsd: fh_compose(exp %02x:%02x/%ld %s/%s, ino=%ld)\n",
335 		MAJOR(ex_dev), MINOR(ex_dev),
336 		(long) exp->ex_dentry->d_inode->i_ino,
337 		parent->d_name.name, dentry->d_name.name,
338 		(inode ? inode->i_ino : 0));
339 
340 	/* Choose filehandle version and fsid type based on
341 	 * the reference filehandle (if it is in the same export)
342 	 * or the export options.
343 	 */
344  retry:
345 	version = 1;
346 	if (ref_fh && ref_fh->fh_export == exp) {
347 		version = ref_fh->fh_handle.fh_version;
348 		fsid_type = ref_fh->fh_handle.fh_fsid_type;
349 
350 		if (ref_fh == fhp)
351 			fh_put(ref_fh);
352 		ref_fh = NULL;
353 
354 		switch (version) {
355 		case 0xca:
356 			fsid_type = FSID_DEV;
357 			break;
358 		case 1:
359 			break;
360 		default:
361 			goto retry;
362 		}
363 
364 		/* Need to check that this type works for this
365 		 * export point.  As the fsid -> filesystem mapping
366 		 * was guided by user-space, there is no guarantee
367 		 * that the filesystem actually supports that fsid
368 		 * type. If it doesn't we loop around again without
369 		 * ref_fh set.
370 		 */
371 		switch(fsid_type) {
372 		case FSID_DEV:
373 			if (!old_valid_dev(ex_dev))
374 				goto retry;
375 			/* FALL THROUGH */
376 		case FSID_MAJOR_MINOR:
377 		case FSID_ENCODE_DEV:
378 			if (!(exp->ex_dentry->d_inode->i_sb->s_type->fs_flags
379 			      & FS_REQUIRES_DEV))
380 				goto retry;
381 			break;
382 		case FSID_NUM:
383 			if (! (exp->ex_flags & NFSEXP_FSID))
384 				goto retry;
385 			break;
386 		case FSID_UUID8:
387 		case FSID_UUID16:
388 			if (!root_export)
389 				goto retry;
390 			/* fall through */
391 		case FSID_UUID4_INUM:
392 		case FSID_UUID16_INUM:
393 			if (exp->ex_uuid == NULL)
394 				goto retry;
395 			break;
396 		}
397 	} else if (exp->ex_uuid) {
398 		if (fhp->fh_maxsize >= 64) {
399 			if (root_export)
400 				fsid_type = FSID_UUID16;
401 			else
402 				fsid_type = FSID_UUID16_INUM;
403 		} else {
404 			if (root_export)
405 				fsid_type = FSID_UUID8;
406 			else
407 				fsid_type = FSID_UUID4_INUM;
408 		}
409 	} else if (exp->ex_flags & NFSEXP_FSID)
410 		fsid_type = FSID_NUM;
411 	else if (!old_valid_dev(ex_dev))
412 		/* for newer device numbers, we must use a newer fsid format */
413 		fsid_type = FSID_ENCODE_DEV;
414 	else
415 		fsid_type = FSID_DEV;
416 
417 	if (ref_fh == fhp)
418 		fh_put(ref_fh);
419 
420 	if (fhp->fh_locked || fhp->fh_dentry) {
421 		printk(KERN_ERR "fh_compose: fh %s/%s not initialized!\n",
422 		       parent->d_name.name, dentry->d_name.name);
423 	}
424 	if (fhp->fh_maxsize < NFS_FHSIZE)
425 		printk(KERN_ERR "fh_compose: called with maxsize %d! %s/%s\n",
426 		       fhp->fh_maxsize,
427 		       parent->d_name.name, dentry->d_name.name);
428 
429 	fhp->fh_dentry = dget(dentry); /* our internal copy */
430 	fhp->fh_export = exp;
431 	cache_get(&exp->h);
432 
433 	if (version == 0xca) {
434 		/* old style filehandle please */
435 		memset(&fhp->fh_handle.fh_base, 0, NFS_FHSIZE);
436 		fhp->fh_handle.fh_size = NFS_FHSIZE;
437 		fhp->fh_handle.ofh_dcookie = 0xfeebbaca;
438 		fhp->fh_handle.ofh_dev =  old_encode_dev(ex_dev);
439 		fhp->fh_handle.ofh_xdev = fhp->fh_handle.ofh_dev;
440 		fhp->fh_handle.ofh_xino =
441 			ino_t_to_u32(exp->ex_dentry->d_inode->i_ino);
442 		fhp->fh_handle.ofh_dirino = ino_t_to_u32(parent_ino(dentry));
443 		if (inode)
444 			_fh_update_old(dentry, exp, &fhp->fh_handle);
445 	} else {
446 		int len;
447 		fhp->fh_handle.fh_version = 1;
448 		fhp->fh_handle.fh_auth_type = 0;
449 		datap = fhp->fh_handle.fh_auth+0;
450 		fhp->fh_handle.fh_fsid_type = fsid_type;
451 		mk_fsid(fsid_type, datap, ex_dev,
452 			exp->ex_dentry->d_inode->i_ino,
453 			exp->ex_fsid, exp->ex_uuid);
454 
455 		len = key_len(fsid_type);
456 		datap += len/4;
457 		fhp->fh_handle.fh_size = 4 + len;
458 
459 		if (inode) {
460 			int size = (fhp->fh_maxsize-len-4)/4;
461 			fhp->fh_handle.fh_fileid_type =
462 				_fh_update(dentry, exp, datap, &size);
463 			fhp->fh_handle.fh_size += size*4;
464 		}
465 		if (fhp->fh_handle.fh_fileid_type == 255)
466 			return nfserr_opnotsupp;
467 	}
468 
469 	nfsd_nr_verified++;
470 	return 0;
471 }
472 
473 /*
474  * Update file handle information after changing a dentry.
475  * This is only called by nfsd_create, nfsd_create_v3 and nfsd_proc_create
476  */
477 __be32
478 fh_update(struct svc_fh *fhp)
479 {
480 	struct dentry *dentry;
481 	__u32 *datap;
482 
483 	if (!fhp->fh_dentry)
484 		goto out_bad;
485 
486 	dentry = fhp->fh_dentry;
487 	if (!dentry->d_inode)
488 		goto out_negative;
489 	if (fhp->fh_handle.fh_version != 1) {
490 		_fh_update_old(dentry, fhp->fh_export, &fhp->fh_handle);
491 	} else {
492 		int size;
493 		if (fhp->fh_handle.fh_fileid_type != 0)
494 			goto out;
495 		datap = fhp->fh_handle.fh_auth+
496 			fhp->fh_handle.fh_size/4 -1;
497 		size = (fhp->fh_maxsize - fhp->fh_handle.fh_size)/4;
498 		fhp->fh_handle.fh_fileid_type =
499 			_fh_update(dentry, fhp->fh_export, datap, &size);
500 		fhp->fh_handle.fh_size += size*4;
501 		if (fhp->fh_handle.fh_fileid_type == 255)
502 			return nfserr_opnotsupp;
503 	}
504 out:
505 	return 0;
506 
507 out_bad:
508 	printk(KERN_ERR "fh_update: fh not verified!\n");
509 	goto out;
510 out_negative:
511 	printk(KERN_ERR "fh_update: %s/%s still negative!\n",
512 		dentry->d_parent->d_name.name, dentry->d_name.name);
513 	goto out;
514 }
515 
516 /*
517  * Release a file handle.
518  */
519 void
520 fh_put(struct svc_fh *fhp)
521 {
522 	struct dentry * dentry = fhp->fh_dentry;
523 	struct svc_export * exp = fhp->fh_export;
524 	if (dentry) {
525 		fh_unlock(fhp);
526 		fhp->fh_dentry = NULL;
527 		dput(dentry);
528 #ifdef CONFIG_NFSD_V3
529 		fhp->fh_pre_saved = 0;
530 		fhp->fh_post_saved = 0;
531 #endif
532 		nfsd_nr_put++;
533 	}
534 	if (exp) {
535 		cache_put(&exp->h, &svc_export_cache);
536 		fhp->fh_export = NULL;
537 	}
538 	return;
539 }
540 
541 /*
542  * Shorthand for dprintk()'s
543  */
544 char * SVCFH_fmt(struct svc_fh *fhp)
545 {
546 	struct knfsd_fh *fh = &fhp->fh_handle;
547 
548 	static char buf[80];
549 	sprintf(buf, "%d: %08x %08x %08x %08x %08x %08x",
550 		fh->fh_size,
551 		fh->fh_base.fh_pad[0],
552 		fh->fh_base.fh_pad[1],
553 		fh->fh_base.fh_pad[2],
554 		fh->fh_base.fh_pad[3],
555 		fh->fh_base.fh_pad[4],
556 		fh->fh_base.fh_pad[5]);
557 	return buf;
558 }
559 
560 enum fsid_source fsid_source(struct svc_fh *fhp)
561 {
562 	if (fhp->fh_handle.fh_version != 1)
563 		return FSIDSOURCE_DEV;
564 	switch(fhp->fh_handle.fh_fsid_type) {
565 	case FSID_DEV:
566 	case FSID_ENCODE_DEV:
567 	case FSID_MAJOR_MINOR:
568 		return FSIDSOURCE_DEV;
569 	case FSID_NUM:
570 		return FSIDSOURCE_FSID;
571 	default:
572 		if (fhp->fh_export->ex_flags & NFSEXP_FSID)
573 			return FSIDSOURCE_FSID;
574 		else
575 			return FSIDSOURCE_UUID;
576 	}
577 }
578