xref: /netbsd-src/sys/nfs/nfs_export.c (revision ba65fde2d7fefa7d39838fa5fa855e62bd606b5e)
1 /*	$NetBSD: nfs_export.c,v 1.51 2011/09/27 01:07:38 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998, 2004, 2005, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center.
10  * This code is derived from software contributed to The NetBSD Foundation
11  * by Charles M. Hannum.
12  * This code is derived from software contributed to The NetBSD Foundation
13  * by Julio M. Merino Vidal.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
27  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
28  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 /*
38  * Copyright (c) 1989, 1993
39  *	The Regents of the University of California.  All rights reserved.
40  * (c) UNIX System Laboratories, Inc.
41  * All or some portions of this file are derived from material licensed
42  * to the University of California by American Telephone and Telegraph
43  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
44  * the permission of UNIX System Laboratories, Inc.
45  *
46  * Redistribution and use in source and binary forms, with or without
47  * modification, are permitted provided that the following conditions
48  * are met:
49  * 1. Redistributions of source code must retain the above copyright
50  *    notice, this list of conditions and the following disclaimer.
51  * 2. Redistributions in binary form must reproduce the above copyright
52  *    notice, this list of conditions and the following disclaimer in the
53  *    documentation and/or other materials provided with the distribution.
54  * 3. Neither the name of the University nor the names of its contributors
55  *    may be used to endorse or promote products derived from this software
56  *    without specific prior written permission.
57  *
58  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68  * SUCH DAMAGE.
69  *
70  *	@(#)vfs_subr.c	8.13 (Berkeley) 4/18/94
71  */
72 
73 /*
74  * VFS exports list management.
75  *
76  * Lock order: vfs_busy -> mnt_updating -> netexport_lock.
77  */
78 
79 #include <sys/cdefs.h>
80 __KERNEL_RCSID(0, "$NetBSD: nfs_export.c,v 1.51 2011/09/27 01:07:38 christos Exp $");
81 
82 #include <sys/param.h>
83 #include <sys/systm.h>
84 #include <sys/kernel.h>
85 #include <sys/queue.h>
86 #include <sys/proc.h>
87 #include <sys/mount.h>
88 #include <sys/vnode.h>
89 #include <sys/namei.h>
90 #include <sys/errno.h>
91 #include <sys/malloc.h>
92 #include <sys/domain.h>
93 #include <sys/mbuf.h>
94 #include <sys/dirent.h>
95 #include <sys/socket.h>		/* XXX for AF_MAX */
96 #include <sys/kauth.h>
97 
98 #include <net/radix.h>
99 
100 #include <netinet/in.h>
101 
102 #include <nfs/rpcv2.h>
103 #include <nfs/nfsproto.h>
104 #include <nfs/nfs.h>
105 #include <nfs/nfs_var.h>
106 
107 /*
108  * Network address lookup element.
109  */
110 struct netcred {
111 	struct	radix_node netc_rnodes[2];
112 	int	netc_refcnt;
113 	int	netc_exflags;
114 	kauth_cred_t netc_anon;
115 };
116 
117 /*
118  * Network export information.
119  */
120 struct netexport {
121 	CIRCLEQ_ENTRY(netexport) ne_list;
122 	struct mount *ne_mount;
123 	struct netcred ne_defexported;		      /* Default export */
124 	struct radix_node_head *ne_rtable[AF_MAX+1]; /* Individual exports */
125 };
126 CIRCLEQ_HEAD(, netexport) netexport_list =
127     CIRCLEQ_HEAD_INITIALIZER(netexport_list);
128 
129 /* Publicly exported file system. */
130 struct nfs_public nfs_pub;
131 
132 /*
133  * Local prototypes.
134  */
135 static int init_exports(struct mount *, struct netexport **);
136 static int hang_addrlist(struct mount *, struct netexport *,
137     const struct export_args *);
138 static int sacheck(struct sockaddr *);
139 static int free_netcred(struct radix_node *, void *);
140 static int export(struct netexport *, const struct export_args *);
141 static int setpublicfs(struct mount *, struct netexport *,
142     const struct export_args *);
143 static struct netcred *netcred_lookup(struct netexport *, struct mbuf *);
144 static struct netexport *netexport_lookup(const struct mount *);
145 static struct netexport *netexport_lookup_byfsid(const fsid_t *);
146 static void netexport_clear(struct netexport *);
147 static void netexport_insert(struct netexport *);
148 static void netexport_remove(struct netexport *);
149 static void netexport_wrlock(void);
150 static void netexport_wrunlock(void);
151 static int nfs_export_update_30(struct mount *mp, const char *path, void *);
152 
153 static krwlock_t netexport_lock;
154 
155 /*
156  * PUBLIC INTERFACE
157  */
158 
159 /*
160  * Declare and initialize the file system export hooks.
161  */
162 static void netexport_unmount(struct mount *);
163 
164 struct vfs_hooks nfs_export_hooks = {
165 	{ NULL, NULL },
166 	.vh_unmount = netexport_unmount,
167 	.vh_reexport = nfs_export_update_30,
168 };
169 
170 /*
171  * VFS unmount hook for NFS exports.
172  *
173  * Releases NFS exports list resources if the given mount point has some.
174  * As allocation happens lazily, it may be that it doesn't has this
175  * information, although it theorically should.
176  */
177 static void
178 netexport_unmount(struct mount *mp)
179 {
180 	struct netexport *ne;
181 
182 	KASSERT(mp != NULL);
183 
184 	netexport_wrlock();
185 	ne = netexport_lookup(mp);
186 	if (ne == NULL) {
187 		netexport_wrunlock();
188 		return;
189 	}
190 	netexport_clear(ne);
191 	netexport_remove(ne);
192 	netexport_wrunlock();
193 	kmem_free(ne, sizeof(*ne));
194 }
195 
196 void
197 netexport_init(void)
198 {
199 
200 	rw_init(&netexport_lock);
201 }
202 
203 void
204 netexport_fini(void)
205 {
206 	struct netexport *ne;
207 	struct mount *mp;
208 	int error;
209 
210 	while (!CIRCLEQ_EMPTY(&netexport_list)) {
211 		netexport_wrlock();
212 		ne = CIRCLEQ_FIRST(&netexport_list);
213 		mp = ne->ne_mount;
214 		error = vfs_busy(mp, NULL);
215 		netexport_wrunlock();
216 		if (error != 0) {
217 			kpause("nfsfini", false, hz, NULL);
218 			continue;
219 		}
220 		mutex_enter(&mp->mnt_updating);	/* mnt_flag */
221 		netexport_unmount(mp);
222 		mutex_exit(&mp->mnt_updating);	/* mnt_flag */
223 		vfs_unbusy(mp, false, NULL);
224 	}
225 	rw_destroy(&netexport_lock);
226 }
227 
228 
229 /*
230  * Atomically set the NFS exports list of the given file system, replacing
231  * it with a new list of entries.
232  *
233  * Returns zero on success or an appropriate error code otherwise.
234  *
235  * Helper function for the nfssvc(2) system call (NFSSVC_SETEXPORTSLIST
236  * command).
237  */
238 int
239 mountd_set_exports_list(const struct mountd_exports_list *mel, struct lwp *l,
240     struct mount *nmp)
241 {
242 	int error;
243 #ifdef notyet
244 	/* XXX: See below to see the reason why this is disabled. */
245 	size_t i;
246 #endif
247 	struct mount *mp;
248 	struct netexport *ne;
249 	struct pathbuf *pb;
250 	struct nameidata nd;
251 	struct vnode *vp;
252 	size_t fid_size;
253 
254 	if (kauth_authorize_network(l->l_cred, KAUTH_NETWORK_NFS,
255 	    KAUTH_REQ_NETWORK_NFS_EXPORT, NULL, NULL, NULL) != 0)
256 		return EPERM;
257 
258 	/* Lookup the file system path. */
259 	error = pathbuf_copyin(mel->mel_path, &pb);
260 	if (error) {
261 		return error;
262 	}
263 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, pb);
264 	error = namei(&nd);
265 	if (error != 0) {
266 		pathbuf_destroy(pb);
267 		return error;
268 	}
269 	vp = nd.ni_vp;
270 	mp = vp->v_mount;
271 	KASSERT(nmp == NULL || nmp == mp);
272 	pathbuf_destroy(pb);
273 
274 	/*
275 	 * Make sure the file system can do vptofh.  If the file system
276 	 * knows the handle's size, just trust it's able to do the
277 	 * actual translation also (otherwise we should check fhtovp
278 	 * also, and that's getting a wee bit ridiculous).
279 	 */
280 	fid_size = 0;
281 	if ((error = VFS_VPTOFH(vp, NULL, &fid_size)) != E2BIG) {
282 		vput(vp);
283 		return EOPNOTSUPP;
284 	}
285 
286 	/* Mark the file system busy. */
287 	error = vfs_busy(mp, NULL);
288 	vput(vp);
289 	if (error != 0)
290 		return error;
291 	if (nmp == NULL)
292 		mutex_enter(&mp->mnt_updating);	/* mnt_flag */
293 	netexport_wrlock();
294 	ne = netexport_lookup(mp);
295 	if (ne == NULL) {
296 		error = init_exports(mp, &ne);
297 		if (error != 0) {
298 			goto out;
299 		}
300 	}
301 
302 	KASSERT(ne != NULL);
303 	KASSERT(ne->ne_mount == mp);
304 
305 	/*
306 	 * XXX: The part marked as 'notyet' works fine from the kernel's
307 	 * point of view, in the sense that it is able to atomically update
308 	 * the complete exports list for a file system.  However, supporting
309 	 * this in mountd(8) requires a lot of work; so, for now, keep the
310 	 * old behavior of updating a single entry per call.
311 	 *
312 	 * When mountd(8) is fixed, just remove the second branch of this
313 	 * preprocessor conditional and enable the first one.
314 	 */
315 #ifdef notyet
316 	netexport_clear(ne);
317 	for (i = 0; error == 0 && i < mel->mel_nexports; i++)
318 		error = export(ne, &mel->mel_exports[i]);
319 #else
320 	if (mel->mel_nexports == 0)
321 		netexport_clear(ne);
322 	else if (mel->mel_nexports == 1)
323 		error = export(ne, &mel->mel_exports[0]);
324 	else {
325 		printf("%s: Cannot set more than one "
326 		    "entry at once (unimplemented)\n", __func__);
327 		error = EOPNOTSUPP;
328 	}
329 #endif
330 
331 out:
332 	netexport_wrunlock();
333 	if (nmp == NULL)
334 		mutex_exit(&mp->mnt_updating);	/* mnt_flag */
335 	vfs_unbusy(mp, false, NULL);
336 	return error;
337 }
338 
339 static void
340 netexport_insert(struct netexport *ne)
341 {
342 
343 	CIRCLEQ_INSERT_HEAD(&netexport_list, ne, ne_list);
344 }
345 
346 static void
347 netexport_remove(struct netexport *ne)
348 {
349 
350 	CIRCLEQ_REMOVE(&netexport_list, ne, ne_list);
351 }
352 
353 static struct netexport *
354 netexport_lookup(const struct mount *mp)
355 {
356 	struct netexport *ne;
357 
358 	CIRCLEQ_FOREACH(ne, &netexport_list, ne_list) {
359 		if (ne->ne_mount == mp) {
360 			goto done;
361 		}
362 	}
363 	ne = NULL;
364 done:
365 	return ne;
366 }
367 
368 static struct netexport *
369 netexport_lookup_byfsid(const fsid_t *fsid)
370 {
371 	struct netexport *ne;
372 
373 	CIRCLEQ_FOREACH(ne, &netexport_list, ne_list) {
374 		const struct mount *mp = ne->ne_mount;
375 
376 		if (mp->mnt_stat.f_fsidx.__fsid_val[0] == fsid->__fsid_val[0] &&
377 		    mp->mnt_stat.f_fsidx.__fsid_val[1] == fsid->__fsid_val[1]) {
378 			goto done;
379 		}
380 	}
381 	ne = NULL;
382 done:
383 
384 	return ne;
385 }
386 
387 /*
388  * Check if the file system specified by the 'mp' mount structure is
389  * exported to a client with 'anon' anonymous credentials.  The 'mb'
390  * argument is an mbuf containing the network address of the client.
391  * The return parameters for the export flags for the client are returned
392  * in the address specified by 'wh'.
393  *
394  * This function is used exclusively by the NFS server.  It is generally
395  * invoked before VFS_FHTOVP to validate that client has access to the
396  * file system.
397  */
398 
399 int
400 netexport_check(const fsid_t *fsid, struct mbuf *mb, struct mount **mpp,
401     int *wh, kauth_cred_t *anon)
402 {
403 	struct netexport *ne;
404 	struct netcred *np;
405 
406 	ne = netexport_lookup_byfsid(fsid);
407 	if (ne == NULL) {
408 		return EACCES;
409 	}
410 	np = netcred_lookup(ne, mb);
411 	if (np == NULL) {
412 		return EACCES;
413 	}
414 
415 	*mpp = ne->ne_mount;
416 	*wh = np->netc_exflags;
417 	*anon = np->netc_anon;
418 
419 	return 0;
420 }
421 
422 /*
423  * Handles legacy export requests.  In this case, the export information
424  * is hardcoded in a specific place of the mount arguments structure (given
425  * in data); the request for an update is given through the fspec field
426  * (also in a known location), which must be a null pointer.
427  *
428  * Returns EJUSTRETURN if the given command was not a export request.
429  * Otherwise, returns 0 on success or an appropriate error code otherwise.
430  */
431 static int
432 nfs_export_update_30(struct mount *mp, const char *path, void *data)
433 {
434 	struct mountd_exports_list mel;
435 	struct mnt_export_args30 *args;
436 
437 	args = data;
438 	mel.mel_path = path;
439 
440 	if (args->fspec != NULL)
441 		return EJUSTRETURN;
442 
443 	if (args->eargs.ex_flags & 0x00020000) {
444 		/* Request to delete exports.  The mask above holds the
445 		 * value that used to be in MNT_DELEXPORT. */
446 		mel.mel_nexports = 0;
447 	} else {
448 		/* The following assumes export_args has not changed since
449 		 * export_args30 - typedef checks sizes. */
450 		typedef char x[sizeof args->eargs == sizeof *mel.mel_exports ? 1 : -1];
451 
452 		mel.mel_nexports = 1;
453 		mel.mel_exports = (void *)&args->eargs;
454 	}
455 
456 	return mountd_set_exports_list(&mel, curlwp, mp);
457 }
458 
459 /*
460  * INTERNAL FUNCTIONS
461  */
462 
463 /*
464  * Initializes NFS exports for the mountpoint given in 'mp'.
465  * If successful, returns 0 and sets *nep to the address of the new
466  * netexport item; otherwise returns an appropriate error code
467  * and *nep remains unmodified.
468  */
469 static int
470 init_exports(struct mount *mp, struct netexport **nep)
471 {
472 	int error;
473 	struct export_args ea;
474 	struct netexport *ne;
475 
476 	KASSERT(mp != NULL);
477 
478 	/* Ensure that we do not already have this mount point. */
479 	KASSERT(netexport_lookup(mp) == NULL);
480 
481 	ne = kmem_zalloc(sizeof(*ne), KM_SLEEP);
482 	ne->ne_mount = mp;
483 
484 	/* Set the default export entry.  Handled internally by export upon
485 	 * first call. */
486 	memset(&ea, 0, sizeof(ea));
487 	ea.ex_root = -2;
488 	if (mp->mnt_flag & MNT_RDONLY)
489 		ea.ex_flags |= MNT_EXRDONLY;
490 	error = export(ne, &ea);
491 	if (error != 0) {
492 		kmem_free(ne, sizeof(*ne));
493 	} else {
494 		netexport_insert(ne);
495 		*nep = ne;
496 	}
497 
498 	return error;
499 }
500 
501 /*
502  * Build hash lists of net addresses and hang them off the mount point.
503  * Called by export() to set up a new entry in the lists of export
504  * addresses.
505  */
506 static int
507 hang_addrlist(struct mount *mp, struct netexport *nep,
508     const struct export_args *argp)
509 {
510 	int error, i;
511 	struct netcred *np, *enp;
512 	struct radix_node_head *rnh;
513 	struct sockaddr *saddr, *smask;
514 	struct domain *dom;
515 
516 	smask = NULL;
517 
518 	if (argp->ex_addrlen == 0) {
519 		if (mp->mnt_flag & MNT_DEFEXPORTED)
520 			return EPERM;
521 		np = &nep->ne_defexported;
522 		KASSERT(np->netc_anon == NULL);
523 		np->netc_anon = kauth_cred_alloc();
524 		np->netc_exflags = argp->ex_flags;
525 		kauth_uucred_to_cred(np->netc_anon, &argp->ex_anon);
526 		mp->mnt_flag |= MNT_DEFEXPORTED;
527 		return 0;
528 	}
529 
530 	if (argp->ex_addrlen > MLEN || argp->ex_masklen > MLEN)
531 		return EINVAL;
532 
533 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
534 	np = malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
535 	np->netc_anon = kauth_cred_alloc();
536 	saddr = (struct sockaddr *)(np + 1);
537 	error = copyin(argp->ex_addr, saddr, argp->ex_addrlen);
538 	if (error)
539 		goto out;
540 	if (saddr->sa_len > argp->ex_addrlen)
541 		saddr->sa_len = argp->ex_addrlen;
542 	if (sacheck(saddr) == -1)
543 		return EINVAL;
544 	if (argp->ex_masklen) {
545 		smask = (struct sockaddr *)((char *)saddr + argp->ex_addrlen);
546 		error = copyin(argp->ex_mask, smask, argp->ex_masklen);
547 		if (error)
548 			goto out;
549 		if (smask->sa_len > argp->ex_masklen)
550 			smask->sa_len = argp->ex_masklen;
551 		if (smask->sa_family != saddr->sa_family)
552 			return EINVAL;
553 		if (sacheck(smask) == -1)
554 			return EINVAL;
555 	}
556 	i = saddr->sa_family;
557 	if ((rnh = nep->ne_rtable[i]) == 0) {
558 		/*
559 		 * Seems silly to initialize every AF when most are not
560 		 * used, do so on demand here
561 		 */
562 		DOMAIN_FOREACH(dom) {
563 			if (dom->dom_family == i && dom->dom_rtattach) {
564 				rn_inithead((void **)&nep->ne_rtable[i],
565 					dom->dom_rtoffset);
566 				break;
567 			}
568 		}
569 		if ((rnh = nep->ne_rtable[i]) == 0) {
570 			error = ENOBUFS;
571 			goto out;
572 		}
573 	}
574 
575 	enp = (struct netcred *)(*rnh->rnh_addaddr)(saddr, smask, rnh,
576 	    np->netc_rnodes);
577 	if (enp != np) {
578 		if (enp == NULL) {
579 			enp = (struct netcred *)(*rnh->rnh_lookup)(saddr,
580 			    smask, rnh);
581 			if (enp == NULL) {
582 				error = EPERM;
583 				goto out;
584 			}
585 		} else
586 			enp->netc_refcnt++;
587 
588 		goto check;
589 	} else
590 		enp->netc_refcnt = 1;
591 
592 	np->netc_exflags = argp->ex_flags;
593 	kauth_uucred_to_cred(np->netc_anon, &argp->ex_anon);
594 	return 0;
595 check:
596 	if (enp->netc_exflags != argp->ex_flags ||
597 	    kauth_cred_uucmp(enp->netc_anon, &argp->ex_anon) != 0)
598 		error = EPERM;
599 	else
600 		error = 0;
601 out:
602 	KASSERT(np->netc_anon != NULL);
603 	kauth_cred_free(np->netc_anon);
604 	free(np, M_NETADDR);
605 	return error;
606 }
607 
608 /*
609  * Ensure that the address stored in 'sa' is valid.
610  * Returns zero on success, otherwise -1.
611  */
612 static int
613 sacheck(struct sockaddr *sa)
614 {
615 
616 	switch (sa->sa_family) {
617 	case AF_INET: {
618 		struct sockaddr_in *sin = (struct sockaddr_in *)sa;
619 		char *p = (char *)sin->sin_zero;
620 		size_t i;
621 
622 		if (sin->sin_len != sizeof(*sin))
623 			return -1;
624 		if (sin->sin_port != 0)
625 			return -1;
626 		for (i = 0; i < sizeof(sin->sin_zero); i++)
627 			if (*p++ != '\0')
628 				return -1;
629 		return 0;
630 	}
631 	case AF_INET6: {
632 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
633 
634 		if (sin6->sin6_len != sizeof(*sin6))
635 			return -1;
636 		if (sin6->sin6_port != 0)
637 			return -1;
638 		return 0;
639 	}
640 	default:
641 		return -1;
642 	}
643 }
644 
645 /*
646  * Free the netcred object pointed to by the 'rn' radix node.
647  * 'w' holds a pointer to the radix tree head.
648  */
649 static int
650 free_netcred(struct radix_node *rn, void *w)
651 {
652 	struct radix_node_head *rnh = (struct radix_node_head *)w;
653 	struct netcred *np = (struct netcred *)(void *)rn;
654 
655 	(*rnh->rnh_deladdr)(rn->rn_key, rn->rn_mask, rnh);
656 	if (--(np->netc_refcnt) <= 0) {
657 		KASSERT(np->netc_anon != NULL);
658 		kauth_cred_free(np->netc_anon);
659 		free(np, M_NETADDR);
660 	}
661 	return 0;
662 }
663 
664 /*
665  * Clears the exports list for a given file system.
666  */
667 static void
668 netexport_clear(struct netexport *ne)
669 {
670 	struct radix_node_head *rnh;
671 	struct mount *mp = ne->ne_mount;
672 	int i;
673 
674 	if (mp->mnt_flag & MNT_EXPUBLIC) {
675 		setpublicfs(NULL, NULL, NULL);
676 		mp->mnt_flag &= ~MNT_EXPUBLIC;
677 	}
678 
679 	for (i = 0; i <= AF_MAX; i++) {
680 		if ((rnh = ne->ne_rtable[i]) != NULL) {
681 			rn_walktree(rnh, free_netcred, rnh);
682 			free(rnh, M_RTABLE);
683 			ne->ne_rtable[i] = NULL;
684 		}
685 	}
686 
687 	if ((mp->mnt_flag & MNT_DEFEXPORTED) != 0) {
688 		struct netcred *np = &ne->ne_defexported;
689 
690 		KASSERT(np->netc_anon != NULL);
691 		kauth_cred_free(np->netc_anon);
692 		np->netc_anon = NULL;
693 	} else {
694 		KASSERT(ne->ne_defexported.netc_anon == NULL);
695 	}
696 
697 	mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
698 }
699 
700 /*
701  * Add a new export entry (described by an export_args structure) to the
702  * given file system.
703  */
704 static int
705 export(struct netexport *nep, const struct export_args *argp)
706 {
707 	struct mount *mp = nep->ne_mount;
708 	int error;
709 
710 	if (argp->ex_flags & MNT_EXPORTED) {
711 		if (argp->ex_flags & MNT_EXPUBLIC) {
712 			if ((error = setpublicfs(mp, nep, argp)) != 0)
713 				return error;
714 			mp->mnt_flag |= MNT_EXPUBLIC;
715 		}
716 		if ((error = hang_addrlist(mp, nep, argp)) != 0)
717 			return error;
718 		mp->mnt_flag |= MNT_EXPORTED;
719 	}
720 	return 0;
721 }
722 
723 /*
724  * Set the publicly exported filesystem (WebNFS).  Currently, only
725  * one public filesystem is possible in the spec (RFC 2054 and 2055)
726  */
727 static int
728 setpublicfs(struct mount *mp, struct netexport *nep,
729     const struct export_args *argp)
730 {
731 	char *cp;
732 	int error;
733 	struct vnode *rvp;
734 	size_t fhsize;
735 
736 	/*
737 	 * mp == NULL -> invalidate the current info, the FS is
738 	 * no longer exported. May be called from either export
739 	 * or unmount, so check if it hasn't already been done.
740 	 */
741 	if (mp == NULL) {
742 		if (nfs_pub.np_valid) {
743 			nfs_pub.np_valid = 0;
744 			if (nfs_pub.np_handle != NULL) {
745 				free(nfs_pub.np_handle, M_TEMP);
746 				nfs_pub.np_handle = NULL;
747 			}
748 			if (nfs_pub.np_index != NULL) {
749 				free(nfs_pub.np_index, M_TEMP);
750 				nfs_pub.np_index = NULL;
751 			}
752 		}
753 		return 0;
754 	}
755 
756 	/*
757 	 * Only one allowed at a time.
758 	 */
759 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
760 		return EBUSY;
761 
762 	/*
763 	 * Get real filehandle for root of exported FS.
764 	 */
765 	if ((error = VFS_ROOT(mp, &rvp)))
766 		return error;
767 
768 	fhsize = 0;
769 	error = vfs_composefh(rvp, NULL, &fhsize);
770 	if (error != E2BIG)
771 		return error;
772 	nfs_pub.np_handle = malloc(fhsize, M_TEMP, M_NOWAIT);
773 	if (nfs_pub.np_handle == NULL)
774 		error = ENOMEM;
775 	else
776 		error = vfs_composefh(rvp, nfs_pub.np_handle, &fhsize);
777 	if (error)
778 		return error;
779 
780 	vput(rvp);
781 
782 	/*
783 	 * If an indexfile was specified, pull it in.
784 	 */
785 	if (argp->ex_indexfile != NULL) {
786 		nfs_pub.np_index = malloc(NFS_MAXNAMLEN + 1, M_TEMP, M_WAITOK);
787 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
788 		    NFS_MAXNAMLEN, (size_t *)0);
789 		if (!error) {
790 			/*
791 			 * Check for illegal filenames.
792 			 */
793 			for (cp = nfs_pub.np_index; *cp; cp++) {
794 				if (*cp == '/') {
795 					error = EINVAL;
796 					break;
797 				}
798 			}
799 		}
800 		if (error) {
801 			free(nfs_pub.np_index, M_TEMP);
802 			return error;
803 		}
804 	}
805 
806 	nfs_pub.np_mount = mp;
807 	nfs_pub.np_valid = 1;
808 	return 0;
809 }
810 
811 /*
812  * Lookup an export entry in the exports list that matches the address
813  * stored in 'nam'.  If no entry is found, the default one is used instead
814  * (if available).
815  */
816 static struct netcred *
817 netcred_lookup(struct netexport *ne, struct mbuf *nam)
818 {
819 	struct netcred *np;
820 	struct radix_node_head *rnh;
821 	struct sockaddr *saddr;
822 
823 	if ((ne->ne_mount->mnt_flag & MNT_EXPORTED) == 0) {
824 		return NULL;
825 	}
826 
827 	/*
828 	 * Lookup in the export list first.
829 	 */
830 	np = NULL;
831 	if (nam != NULL) {
832 		saddr = mtod(nam, struct sockaddr *);
833 		rnh = ne->ne_rtable[saddr->sa_family];
834 		if (rnh != NULL) {
835 			np = (struct netcred *)
836 				(*rnh->rnh_matchaddr)((void *)saddr,
837 						      rnh);
838 			if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
839 				np = NULL;
840 		}
841 	}
842 	/*
843 	 * If no address match, use the default if it exists.
844 	 */
845 	if (np == NULL && ne->ne_mount->mnt_flag & MNT_DEFEXPORTED)
846 		np = &ne->ne_defexported;
847 
848 	return np;
849 }
850 
851 void
852 netexport_rdlock(void)
853 {
854 
855 	rw_enter(&netexport_lock, RW_READER);
856 }
857 
858 void
859 netexport_rdunlock(void)
860 {
861 
862 	rw_exit(&netexport_lock);
863 }
864 
865 static void
866 netexport_wrlock(void)
867 {
868 
869 	rw_enter(&netexport_lock, RW_WRITER);
870 }
871 
872 static void
873 netexport_wrunlock(void)
874 {
875 
876 	rw_exit(&netexport_lock);
877 }
878