xref: /freebsd/sys/kern/vfs_export.c (revision 8a271827e7b5d5310e06df1f9f49ba0ef9efd263)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
37  */
38 
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 #include "opt_inet.h"
43 #include "opt_inet6.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/dirent.h>
48 #include <sys/jail.h>
49 #include <sys/kernel.h>
50 #include <sys/lock.h>
51 #include <sys/malloc.h>
52 #include <sys/mbuf.h>
53 #include <sys/mount.h>
54 #include <sys/mutex.h>
55 #include <sys/proc.h>
56 #include <sys/rmlock.h>
57 #include <sys/refcount.h>
58 #include <sys/signalvar.h>
59 #include <sys/socket.h>
60 #include <sys/vnode.h>
61 
62 #include <netinet/in.h>
63 #include <net/radix.h>
64 
65 #include <rpc/types.h>
66 #include <rpc/auth.h>
67 
68 static MALLOC_DEFINE(M_NETADDR, "export_host", "Export host address structure");
69 
70 #if defined(INET) || defined(INET6)
71 static struct radix_node_head *vfs_create_addrlist_af(
72 		    struct radix_node_head **prnh, int off);
73 #endif
74 static int	vfs_free_netcred(struct radix_node *rn, void *w);
75 static void	vfs_free_addrlist_af(struct radix_node_head **prnh);
76 static int	vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
77 		    struct export_args *argp);
78 static struct netcred *vfs_export_lookup(struct mount *, struct sockaddr *);
79 
80 /*
81  * Network address lookup element
82  */
83 struct netcred {
84 	struct	radix_node netc_rnodes[2];
85 	uint64_t netc_exflags;
86 	struct	ucred *netc_anon;
87 	int	netc_numsecflavors;
88 	int	netc_secflavors[MAXSECFLAVORS];
89 };
90 
91 /*
92  * Network export information
93  */
94 struct netexport {
95 	struct	netcred ne_defexported;		      /* Default export */
96 	struct 	radix_node_head	*ne4;
97 	struct 	radix_node_head	*ne6;
98 };
99 
100 /*
101  * Build hash lists of net addresses and hang them off the mount point.
102  * Called by vfs_export() to set up the lists of export addresses.
103  */
104 static int
105 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
106     struct export_args *argp)
107 {
108 	struct netcred *np;
109 	struct radix_node_head *rnh;
110 	int i;
111 	struct radix_node *rn;
112 	struct sockaddr *saddr, *smask = NULL;
113 #if defined(INET6) || defined(INET)
114 	int off;
115 #endif
116 	int error;
117 
118 	KASSERT(argp->ex_numsecflavors > 0,
119 	    ("%s: numsecflavors <= 0", __func__));
120 	KASSERT(argp->ex_numsecflavors < MAXSECFLAVORS,
121 	    ("%s: numsecflavors >= MAXSECFLAVORS", __func__));
122 
123 	/*
124 	 * XXX: This routine converts from a uid plus gid list
125 	 * to a `struct ucred' (np->netc_anon).  This
126 	 * operation is questionable; for example, what should be done
127 	 * with fields like cr_uidinfo and cr_prison?  Currently, this
128 	 * routine does not touch them (leaves them as NULL).
129 	 */
130 	if (argp->ex_addrlen == 0) {
131 		if (mp->mnt_flag & MNT_DEFEXPORTED) {
132 			vfs_mount_error(mp,
133 			    "MNT_DEFEXPORTED already set for mount %p", mp);
134 			return (EPERM);
135 		}
136 		np = &nep->ne_defexported;
137 		np->netc_exflags = argp->ex_flags;
138 		np->netc_anon = crget();
139 		np->netc_anon->cr_uid = argp->ex_uid;
140 		crsetgroups(np->netc_anon, argp->ex_ngroups,
141 		    argp->ex_groups);
142 		np->netc_anon->cr_prison = &prison0;
143 		prison_hold(np->netc_anon->cr_prison);
144 		np->netc_numsecflavors = argp->ex_numsecflavors;
145 		bcopy(argp->ex_secflavors, np->netc_secflavors,
146 		    sizeof(np->netc_secflavors));
147 		MNT_ILOCK(mp);
148 		mp->mnt_flag |= MNT_DEFEXPORTED;
149 		MNT_IUNLOCK(mp);
150 		return (0);
151 	}
152 
153 #if MSIZE <= 256
154 	if (argp->ex_addrlen > MLEN) {
155 		vfs_mount_error(mp, "ex_addrlen %d is greater than %d",
156 		    argp->ex_addrlen, MLEN);
157 		return (EINVAL);
158 	}
159 #endif
160 
161 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
162 	np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
163 	saddr = (struct sockaddr *) (np + 1);
164 	if ((error = copyin(argp->ex_addr, saddr, argp->ex_addrlen)))
165 		goto out;
166 	if (saddr->sa_family == AF_UNSPEC || saddr->sa_family > AF_MAX) {
167 		error = EINVAL;
168 		vfs_mount_error(mp, "Invalid saddr->sa_family: %d");
169 		goto out;
170 	}
171 	if (saddr->sa_len > argp->ex_addrlen)
172 		saddr->sa_len = argp->ex_addrlen;
173 	if (argp->ex_masklen) {
174 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
175 		error = copyin(argp->ex_mask, smask, argp->ex_masklen);
176 		if (error)
177 			goto out;
178 		if (smask->sa_len > argp->ex_masklen)
179 			smask->sa_len = argp->ex_masklen;
180 	}
181 	rnh = NULL;
182 	switch (saddr->sa_family) {
183 #ifdef INET
184 	case AF_INET:
185 		if ((rnh = nep->ne4) == NULL) {
186 			off = offsetof(struct sockaddr_in, sin_addr) << 3;
187 			rnh = vfs_create_addrlist_af(&nep->ne4, off);
188 		}
189 		break;
190 #endif
191 #ifdef INET6
192 	case AF_INET6:
193 		if ((rnh = nep->ne6) == NULL) {
194 			off = offsetof(struct sockaddr_in6, sin6_addr) << 3;
195 			rnh = vfs_create_addrlist_af(&nep->ne6, off);
196 		}
197 		break;
198 #endif
199 	}
200 	if (rnh == NULL) {
201 		error = ENOBUFS;
202 		vfs_mount_error(mp, "%s %s %d",
203 		    "Unable to initialize radix node head ",
204 		    "for address family", saddr->sa_family);
205 		goto out;
206 	}
207 	RADIX_NODE_HEAD_LOCK(rnh);
208 	rn = (*rnh->rnh_addaddr)(saddr, smask, &rnh->rh, np->netc_rnodes);
209 	RADIX_NODE_HEAD_UNLOCK(rnh);
210 	if (rn == NULL || np != (struct netcred *)rn) {	/* already exists */
211 		error = EPERM;
212 		vfs_mount_error(mp,
213 		    "netcred already exists for given addr/mask");
214 		goto out;
215 	}
216 	np->netc_exflags = argp->ex_flags;
217 	np->netc_anon = crget();
218 	np->netc_anon->cr_uid = argp->ex_uid;
219 	crsetgroups(np->netc_anon, argp->ex_ngroups,
220 	    argp->ex_groups);
221 	np->netc_anon->cr_prison = &prison0;
222 	prison_hold(np->netc_anon->cr_prison);
223 	np->netc_numsecflavors = argp->ex_numsecflavors;
224 	bcopy(argp->ex_secflavors, np->netc_secflavors,
225 	    sizeof(np->netc_secflavors));
226 	return (0);
227 out:
228 	free(np, M_NETADDR);
229 	return (error);
230 }
231 
232 /* Helper for vfs_free_addrlist. */
233 /* ARGSUSED */
234 static int
235 vfs_free_netcred(struct radix_node *rn, void *w)
236 {
237 	struct radix_node_head *rnh = (struct radix_node_head *) w;
238 	struct ucred *cred;
239 
240 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, &rnh->rh);
241 	cred = ((struct netcred *)rn)->netc_anon;
242 	if (cred != NULL)
243 		crfree(cred);
244 	free(rn, M_NETADDR);
245 	return (0);
246 }
247 
248 #if defined(INET) || defined(INET6)
249 static struct radix_node_head *
250 vfs_create_addrlist_af(struct radix_node_head **prnh, int off)
251 {
252 
253 	if (rn_inithead((void **)prnh, off) == 0)
254 		return (NULL);
255 	RADIX_NODE_HEAD_LOCK_INIT(*prnh);
256 	return (*prnh);
257 }
258 #endif
259 
260 static void
261 vfs_free_addrlist_af(struct radix_node_head **prnh)
262 {
263 	struct radix_node_head *rnh;
264 
265 	rnh = *prnh;
266 	RADIX_NODE_HEAD_LOCK(rnh);
267 	(*rnh->rnh_walktree)(&rnh->rh, vfs_free_netcred, rnh);
268 	RADIX_NODE_HEAD_UNLOCK(rnh);
269 	RADIX_NODE_HEAD_DESTROY(rnh);
270 	rn_detachhead((void **)prnh);
271 	prnh = NULL;
272 }
273 
274 /*
275  * Free the net address hash lists that are hanging off the mount points.
276  */
277 void
278 vfs_free_addrlist(struct netexport *nep)
279 {
280 	struct ucred *cred;
281 
282 	if (nep->ne4 != NULL)
283 		vfs_free_addrlist_af(&nep->ne4);
284 	if (nep->ne6 != NULL)
285 		vfs_free_addrlist_af(&nep->ne6);
286 
287 	cred = nep->ne_defexported.netc_anon;
288 	if (cred != NULL) {
289 		crfree(cred);
290 		nep->ne_defexported.netc_anon = NULL;
291 	}
292 
293 }
294 
295 /*
296  * High level function to manipulate export options on a mount point
297  * and the passed in netexport.
298  * Struct export_args *argp is the variable used to twiddle options,
299  * the structure is described in sys/mount.h
300  * The do_exjail argument should be true if *mp is in the mountlist
301  * and false if not.  It is not in the mountlist for the NFSv4 rootfs
302  * fake mount point just used for exports.
303  */
304 int
305 vfs_export(struct mount *mp, struct export_args *argp, bool do_exjail)
306 {
307 	struct netexport *nep;
308 	struct ucred *cr;
309 	struct prison *pr;
310 	int error;
311 	bool new_nep;
312 
313 	if ((argp->ex_flags & (MNT_DELEXPORT | MNT_EXPORTED)) == 0)
314 		return (EINVAL);
315 
316 	if ((argp->ex_flags & MNT_EXPORTED) != 0 &&
317 	    (argp->ex_numsecflavors < 0
318 	    || argp->ex_numsecflavors >= MAXSECFLAVORS))
319 		return (EINVAL);
320 
321 	error = 0;
322 	pr = curthread->td_ucred->cr_prison;
323 	lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
324 	nep = mp->mnt_export;
325 	if (argp->ex_flags & MNT_DELEXPORT) {
326 		if (nep == NULL) {
327 			error = ENOENT;
328 			goto out;
329 		}
330 		MNT_ILOCK(mp);
331 		if (mp->mnt_exjail != NULL && mp->mnt_exjail->cr_prison != pr &&
332 		    pr == &prison0) {
333 			MNT_IUNLOCK(mp);
334 			/* EXDEV will not get logged by mountd(8). */
335 			error = EXDEV;
336 			goto out;
337 		} else if (mp->mnt_exjail != NULL &&
338 		    mp->mnt_exjail->cr_prison != pr) {
339 			MNT_IUNLOCK(mp);
340 			/* EPERM will get logged by mountd(8). */
341 			error = EPERM;
342 			goto out;
343 		}
344 		MNT_IUNLOCK(mp);
345 		if (mp->mnt_flag & MNT_EXPUBLIC) {
346 			vfs_setpublicfs(NULL, NULL, NULL);
347 			MNT_ILOCK(mp);
348 			mp->mnt_flag &= ~MNT_EXPUBLIC;
349 			MNT_IUNLOCK(mp);
350 		}
351 		vfs_free_addrlist(nep);
352 		mp->mnt_export = NULL;
353 		free(nep, M_MOUNT);
354 		nep = NULL;
355 		MNT_ILOCK(mp);
356 		cr = mp->mnt_exjail;
357 		mp->mnt_exjail = NULL;
358 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
359 		MNT_IUNLOCK(mp);
360 		if (cr != NULL) {
361 			atomic_subtract_int(&pr->pr_exportcnt, 1);
362 			crfree(cr);
363 		}
364 	}
365 	if (argp->ex_flags & MNT_EXPORTED) {
366 		new_nep = false;
367 		MNT_ILOCK(mp);
368 		if (mp->mnt_exjail == NULL) {
369 			MNT_IUNLOCK(mp);
370 			if (do_exjail && nep != NULL) {
371 				vfs_free_addrlist(nep);
372 				memset(nep, 0, sizeof(*nep));
373 				new_nep = true;
374 			}
375 		} else if (mp->mnt_exjail->cr_prison != pr) {
376 			MNT_IUNLOCK(mp);
377 			error = EPERM;
378 			goto out;
379 		} else
380 			MNT_IUNLOCK(mp);
381 		if (nep == NULL) {
382 			nep = malloc(sizeof(struct netexport), M_MOUNT,
383 			    M_WAITOK | M_ZERO);
384 			mp->mnt_export = nep;
385 			new_nep = true;
386 		}
387 		if (argp->ex_flags & MNT_EXPUBLIC) {
388 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0) {
389 				if (new_nep) {
390 					mp->mnt_export = NULL;
391 					free(nep, M_MOUNT);
392 				}
393 				goto out;
394 			}
395 			new_nep = false;
396 			MNT_ILOCK(mp);
397 			if (do_exjail && mp->mnt_exjail == NULL) {
398 				mp->mnt_exjail = crhold(curthread->td_ucred);
399 				atomic_add_int(&pr->pr_exportcnt, 1);
400 			}
401 			mp->mnt_flag |= MNT_EXPUBLIC;
402 			MNT_IUNLOCK(mp);
403 		}
404 		if (argp->ex_numsecflavors == 0) {
405 			argp->ex_numsecflavors = 1;
406 			argp->ex_secflavors[0] = AUTH_SYS;
407 		}
408 		if ((error = vfs_hang_addrlist(mp, nep, argp))) {
409 			if (new_nep) {
410 				mp->mnt_export = NULL;
411 				free(nep, M_MOUNT);
412 			}
413 			goto out;
414 		}
415 		MNT_ILOCK(mp);
416 		if (do_exjail && mp->mnt_exjail == NULL) {
417 			mp->mnt_exjail = crhold(curthread->td_ucred);
418 			atomic_add_int(&pr->pr_exportcnt, 1);
419 		}
420 		mp->mnt_flag |= MNT_EXPORTED;
421 		MNT_IUNLOCK(mp);
422 	}
423 
424 out:
425 	lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
426 	/*
427 	 * Once we have executed the vfs_export() command, we do
428 	 * not want to keep the "export" option around in the
429 	 * options list, since that will cause subsequent MNT_UPDATE
430 	 * calls to fail.  The export information is saved in
431 	 * mp->mnt_export, so we can safely delete the "export" mount option
432 	 * here.
433 	 */
434 	vfs_deleteopt(mp->mnt_optnew, "export");
435 	vfs_deleteopt(mp->mnt_opt, "export");
436 	return (error);
437 }
438 
439 /*
440  * Get rid of credential references for this prison.
441  */
442 void
443 vfs_exjail_delete(struct prison *pr)
444 {
445 	struct mount *mp;
446 	struct ucred *cr;
447 	int error, i;
448 
449 	/*
450 	 * Since this function is called from prison_cleanup() after
451 	 * all processes in the prison have exited, the value of
452 	 * pr_exportcnt can no longer increase.  It is possible for
453 	 * a dismount of a file system exported within this prison
454 	 * to be in progress.  In this case, the file system is no
455 	 * longer in the mountlist and the mnt_exjail will be free'd
456 	 * by vfs_mount_destroy() at some time.  As such, pr_exportcnt
457 	 * and, therefore "i", is the upper bound on the number of
458 	 * mnt_exjail entries to be found by this function.
459 	 */
460 	i = atomic_load_int(&pr->pr_exportcnt);
461 	KASSERT(i >= 0, ("vfs_exjail_delete: pr_exportcnt negative"));
462 	if (i == 0)
463 		return;
464 	mtx_lock(&mountlist_mtx);
465 tryagain:
466 	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
467 		MNT_ILOCK(mp);
468 		if (mp->mnt_exjail != NULL &&
469 		    mp->mnt_exjail->cr_prison == pr) {
470 			MNT_IUNLOCK(mp);
471 			error = vfs_busy(mp, MBF_MNTLSTLOCK | MBF_NOWAIT);
472 			if (error != 0) {
473 				/*
474 				 * If the vfs_busy() fails, we still want to
475 				 * get rid of mnt_exjail for two reasons:
476 				 * - a credential reference will result in
477 				 *   a prison not being removed
478 				 * - setting mnt_exjail NULL indicates that
479 				 *   the exports are no longer valid
480 				 * The now invalid exports will be deleted
481 				 * when the file system is dismounted or
482 				 * the file system is re-exported by mountd.
483 				 */
484 				cr = NULL;
485 				MNT_ILOCK(mp);
486 				if (mp->mnt_exjail != NULL &&
487 				    mp->mnt_exjail->cr_prison == pr) {
488 					cr = mp->mnt_exjail;
489 					mp->mnt_exjail = NULL;
490 				}
491 				MNT_IUNLOCK(mp);
492 				if (cr != NULL) {
493 					crfree(cr);
494 					i--;
495 				}
496 				if (i == 0)
497 					break;
498 				continue;
499 			}
500 			cr = NULL;
501 			lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
502 			MNT_ILOCK(mp);
503 			if (mp->mnt_exjail != NULL &&
504 			    mp->mnt_exjail->cr_prison == pr) {
505 				cr = mp->mnt_exjail;
506 				mp->mnt_exjail = NULL;
507 				mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
508 				MNT_IUNLOCK(mp);
509 				vfs_free_addrlist(mp->mnt_export);
510 				free(mp->mnt_export, M_MOUNT);
511 				mp->mnt_export = NULL;
512 			} else
513 				MNT_IUNLOCK(mp);
514 			lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
515 			if (cr != NULL) {
516 				crfree(cr);
517 				i--;
518 			}
519 			mtx_lock(&mountlist_mtx);
520 			vfs_unbusy(mp);
521 			if (i == 0)
522 				break;
523 			goto tryagain;
524 		}
525 		MNT_IUNLOCK(mp);
526 	}
527 	mtx_unlock(&mountlist_mtx);
528 }
529 
530 /*
531  * Set the publicly exported filesystem (WebNFS). Currently, only
532  * one public filesystem is possible in the spec (RFC 2054 and 2055)
533  */
534 int
535 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
536     struct export_args *argp)
537 {
538 	int error;
539 	struct vnode *rvp;
540 	char *cp;
541 
542 	/*
543 	 * mp == NULL -> invalidate the current info, the FS is
544 	 * no longer exported. May be called from either vfs_export
545 	 * or unmount, so check if it hasn't already been done.
546 	 */
547 	if (mp == NULL) {
548 		if (nfs_pub.np_valid) {
549 			nfs_pub.np_valid = 0;
550 			if (nfs_pub.np_index != NULL) {
551 				free(nfs_pub.np_index, M_TEMP);
552 				nfs_pub.np_index = NULL;
553 			}
554 		}
555 		return (0);
556 	}
557 
558 	/*
559 	 * Only one allowed at a time.
560 	 */
561 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
562 		return (EBUSY);
563 
564 	/*
565 	 * Get real filehandle for root of exported FS.
566 	 */
567 	bzero(&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
568 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
569 
570 	if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rvp)))
571 		return (error);
572 
573 	if ((error = VOP_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
574 		return (error);
575 
576 	vput(rvp);
577 
578 	/*
579 	 * If an indexfile was specified, pull it in.
580 	 */
581 	if (argp->ex_indexfile != NULL) {
582 		if (nfs_pub.np_index == NULL)
583 			nfs_pub.np_index = malloc(MAXNAMLEN + 1, M_TEMP,
584 			    M_WAITOK);
585 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
586 		    MAXNAMLEN, (size_t *)0);
587 		if (!error) {
588 			/*
589 			 * Check for illegal filenames.
590 			 */
591 			for (cp = nfs_pub.np_index; *cp; cp++) {
592 				if (*cp == '/') {
593 					error = EINVAL;
594 					break;
595 				}
596 			}
597 		}
598 		if (error) {
599 			free(nfs_pub.np_index, M_TEMP);
600 			nfs_pub.np_index = NULL;
601 			return (error);
602 		}
603 	}
604 
605 	nfs_pub.np_mount = mp;
606 	nfs_pub.np_valid = 1;
607 	return (0);
608 }
609 
610 /*
611  * Used by the filesystems to determine if a given network address
612  * (passed in 'nam') is present in their exports list, returns a pointer
613  * to struct netcred so that the filesystem can examine it for
614  * access rights (read/write/etc).
615  */
616 static struct netcred *
617 vfs_export_lookup(struct mount *mp, struct sockaddr *nam)
618 {
619 	RADIX_NODE_HEAD_RLOCK_TRACKER;
620 	struct netexport *nep;
621 	struct netcred *np = NULL;
622 	struct radix_node_head *rnh;
623 	struct sockaddr *saddr;
624 
625 	nep = mp->mnt_export;
626 	if (nep == NULL)
627 		return (NULL);
628 	if ((mp->mnt_flag & MNT_EXPORTED) == 0)
629 		return (NULL);
630 
631 	/*
632 	 * Lookup in the export list
633 	 */
634 	if (nam != NULL) {
635 		saddr = nam;
636 		rnh = NULL;
637 		switch (saddr->sa_family) {
638 		case AF_INET:
639 			rnh = nep->ne4;
640 			break;
641 		case AF_INET6:
642 			rnh = nep->ne6;
643 			break;
644 		}
645 		if (rnh != NULL) {
646 			RADIX_NODE_HEAD_RLOCK(rnh);
647 			np = (struct netcred *) (*rnh->rnh_matchaddr)(saddr, &rnh->rh);
648 			RADIX_NODE_HEAD_RUNLOCK(rnh);
649 			if (np != NULL && (np->netc_rnodes->rn_flags & RNF_ROOT) != 0)
650 				return (NULL);
651 		}
652 	}
653 
654 	/*
655 	 * If no address match, use the default if it exists.
656 	 */
657 	if (np == NULL && (mp->mnt_flag & MNT_DEFEXPORTED) != 0)
658 		return (&nep->ne_defexported);
659 
660 	return (np);
661 }
662 
663 /*
664  * XXX: This comment comes from the deprecated ufs_check_export()
665  * XXX: and may not entirely apply, but lacking something better:
666  * This is the generic part of fhtovp called after the underlying
667  * filesystem has validated the file handle.
668  *
669  * Verify that a host should have access to a filesystem.
670  */
671 
672 int
673 vfs_stdcheckexp(struct mount *mp, struct sockaddr *nam, uint64_t *extflagsp,
674     struct ucred **credanonp, int *numsecflavors, int *secflavors)
675 {
676 	struct netcred *np;
677 
678 	lockmgr(&mp->mnt_explock, LK_SHARED, NULL);
679 	np = vfs_export_lookup(mp, nam);
680 	if (np == NULL) {
681 		lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
682 		*credanonp = NULL;
683 		return (EACCES);
684 	}
685 	*extflagsp = np->netc_exflags;
686 	if ((*credanonp = np->netc_anon) != NULL)
687 		crhold(*credanonp);
688 	if (numsecflavors) {
689 		*numsecflavors = np->netc_numsecflavors;
690 		KASSERT(*numsecflavors > 0,
691 		    ("%s: numsecflavors <= 0", __func__));
692 		KASSERT(*numsecflavors < MAXSECFLAVORS,
693 		    ("%s: numsecflavors >= MAXSECFLAVORS", __func__));
694 	}
695 	if (secflavors && np->netc_numsecflavors > 0)
696 		memcpy(secflavors, np->netc_secflavors, np->netc_numsecflavors *
697 		    sizeof(int));
698 	lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
699 	return (0);
700 }
701