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/rmlock.h>
56#include <sys/refcount.h>
57#include <sys/signalvar.h>
58#include <sys/socket.h>
59#include <sys/vnode.h>
60
61#include <netinet/in.h>
62#include <net/radix.h>
63
64#include <rpc/types.h>
65#include <rpc/auth.h>
66
67static MALLOC_DEFINE(M_NETADDR, "export_host", "Export host address structure");
68
69#if defined(INET) || defined(INET6)
70static struct radix_node_head *vfs_create_addrlist_af(
71		    struct radix_node_head **prnh, int off);
72#endif
73static void	vfs_free_addrlist(struct netexport *nep);
74static int	vfs_free_netcred(struct radix_node *rn, void *w);
75static void	vfs_free_addrlist_af(struct radix_node_head **prnh);
76static int	vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
77		    struct export_args *argp);
78static struct netcred *vfs_export_lookup(struct mount *, struct sockaddr *);
79
80/*
81 * Network address lookup element
82 */
83struct 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 */
94struct 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 */
104static int
105vfs_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);
227out:
228	free(np, M_NETADDR);
229	return (error);
230}
231
232/* Helper for vfs_free_addrlist. */
233/* ARGSUSED */
234static int
235vfs_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)
249static struct radix_node_head *
250vfs_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
260static void
261vfs_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 */
277static void
278vfs_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
291}
292
293/*
294 * High level function to manipulate export options on a mount point
295 * and the passed in netexport.
296 * Struct export_args *argp is the variable used to twiddle options,
297 * the structure is described in sys/mount.h
298 */
299int
300vfs_export(struct mount *mp, struct export_args *argp)
301{
302	struct netexport *nep;
303	int error;
304
305	if ((argp->ex_flags & (MNT_DELEXPORT | MNT_EXPORTED)) == 0)
306		return (EINVAL);
307
308	if ((argp->ex_flags & MNT_EXPORTED) != 0 &&
309	    (argp->ex_numsecflavors < 0
310	    || argp->ex_numsecflavors >= MAXSECFLAVORS))
311		return (EINVAL);
312
313	error = 0;
314	lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
315	nep = mp->mnt_export;
316	if (argp->ex_flags & MNT_DELEXPORT) {
317		if (nep == NULL) {
318			error = ENOENT;
319			goto out;
320		}
321		if (mp->mnt_flag & MNT_EXPUBLIC) {
322			vfs_setpublicfs(NULL, NULL, NULL);
323			MNT_ILOCK(mp);
324			mp->mnt_flag &= ~MNT_EXPUBLIC;
325			MNT_IUNLOCK(mp);
326		}
327		vfs_free_addrlist(nep);
328		mp->mnt_export = NULL;
329		free(nep, M_MOUNT);
330		nep = NULL;
331		MNT_ILOCK(mp);
332		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
333		MNT_IUNLOCK(mp);
334	}
335	if (argp->ex_flags & MNT_EXPORTED) {
336		if (nep == NULL) {
337			nep = malloc(sizeof(struct netexport), M_MOUNT, M_WAITOK | M_ZERO);
338			mp->mnt_export = nep;
339		}
340		if (argp->ex_flags & MNT_EXPUBLIC) {
341			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
342				goto out;
343			MNT_ILOCK(mp);
344			mp->mnt_flag |= MNT_EXPUBLIC;
345			MNT_IUNLOCK(mp);
346		}
347		if (argp->ex_numsecflavors == 0) {
348			argp->ex_numsecflavors = 1;
349			argp->ex_secflavors[0] = AUTH_SYS;
350		}
351		if ((error = vfs_hang_addrlist(mp, nep, argp)))
352			goto out;
353		MNT_ILOCK(mp);
354		mp->mnt_flag |= MNT_EXPORTED;
355		MNT_IUNLOCK(mp);
356	}
357
358out:
359	lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
360	/*
361	 * Once we have executed the vfs_export() command, we do
362	 * not want to keep the "export" option around in the
363	 * options list, since that will cause subsequent MNT_UPDATE
364	 * calls to fail.  The export information is saved in
365	 * mp->mnt_export, so we can safely delete the "export" mount option
366	 * here.
367	 */
368	vfs_deleteopt(mp->mnt_optnew, "export");
369	vfs_deleteopt(mp->mnt_opt, "export");
370	return (error);
371}
372
373/*
374 * Set the publicly exported filesystem (WebNFS). Currently, only
375 * one public filesystem is possible in the spec (RFC 2054 and 2055)
376 */
377int
378vfs_setpublicfs(struct mount *mp, struct netexport *nep,
379    struct export_args *argp)
380{
381	int error;
382	struct vnode *rvp;
383	char *cp;
384
385	/*
386	 * mp == NULL -> invalidate the current info, the FS is
387	 * no longer exported. May be called from either vfs_export
388	 * or unmount, so check if it hasn't already been done.
389	 */
390	if (mp == NULL) {
391		if (nfs_pub.np_valid) {
392			nfs_pub.np_valid = 0;
393			if (nfs_pub.np_index != NULL) {
394				free(nfs_pub.np_index, M_TEMP);
395				nfs_pub.np_index = NULL;
396			}
397		}
398		return (0);
399	}
400
401	/*
402	 * Only one allowed at a time.
403	 */
404	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
405		return (EBUSY);
406
407	/*
408	 * Get real filehandle for root of exported FS.
409	 */
410	bzero(&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
411	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
412
413	if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rvp)))
414		return (error);
415
416	if ((error = VOP_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
417		return (error);
418
419	vput(rvp);
420
421	/*
422	 * If an indexfile was specified, pull it in.
423	 */
424	if (argp->ex_indexfile != NULL) {
425		if (nfs_pub.np_index == NULL)
426			nfs_pub.np_index = malloc(MAXNAMLEN + 1, M_TEMP,
427			    M_WAITOK);
428		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
429		    MAXNAMLEN, (size_t *)0);
430		if (!error) {
431			/*
432			 * Check for illegal filenames.
433			 */
434			for (cp = nfs_pub.np_index; *cp; cp++) {
435				if (*cp == '/') {
436					error = EINVAL;
437					break;
438				}
439			}
440		}
441		if (error) {
442			free(nfs_pub.np_index, M_TEMP);
443			nfs_pub.np_index = NULL;
444			return (error);
445		}
446	}
447
448	nfs_pub.np_mount = mp;
449	nfs_pub.np_valid = 1;
450	return (0);
451}
452
453/*
454 * Used by the filesystems to determine if a given network address
455 * (passed in 'nam') is present in their exports list, returns a pointer
456 * to struct netcred so that the filesystem can examine it for
457 * access rights (read/write/etc).
458 */
459static struct netcred *
460vfs_export_lookup(struct mount *mp, struct sockaddr *nam)
461{
462	RADIX_NODE_HEAD_RLOCK_TRACKER;
463	struct netexport *nep;
464	struct netcred *np = NULL;
465	struct radix_node_head *rnh;
466	struct sockaddr *saddr;
467
468	nep = mp->mnt_export;
469	if (nep == NULL)
470		return (NULL);
471	if ((mp->mnt_flag & MNT_EXPORTED) == 0)
472		return (NULL);
473
474	/*
475	 * Lookup in the export list
476	 */
477	if (nam != NULL) {
478		saddr = nam;
479		rnh = NULL;
480		switch (saddr->sa_family) {
481		case AF_INET:
482			rnh = nep->ne4;
483			break;
484		case AF_INET6:
485			rnh = nep->ne6;
486			break;
487		}
488		if (rnh != NULL) {
489			RADIX_NODE_HEAD_RLOCK(rnh);
490			np = (struct netcred *) (*rnh->rnh_matchaddr)(saddr, &rnh->rh);
491			RADIX_NODE_HEAD_RUNLOCK(rnh);
492			if (np != NULL && (np->netc_rnodes->rn_flags & RNF_ROOT) != 0)
493				return (NULL);
494		}
495	}
496
497	/*
498	 * If no address match, use the default if it exists.
499	 */
500	if (np == NULL && (mp->mnt_flag & MNT_DEFEXPORTED) != 0)
501		return (&nep->ne_defexported);
502
503	return (np);
504}
505
506/*
507 * XXX: This comment comes from the deprecated ufs_check_export()
508 * XXX: and may not entirely apply, but lacking something better:
509 * This is the generic part of fhtovp called after the underlying
510 * filesystem has validated the file handle.
511 *
512 * Verify that a host should have access to a filesystem.
513 */
514
515int
516vfs_stdcheckexp(struct mount *mp, struct sockaddr *nam, uint64_t *extflagsp,
517    struct ucred **credanonp, int *numsecflavors, int *secflavors)
518{
519	struct netcred *np;
520
521	lockmgr(&mp->mnt_explock, LK_SHARED, NULL);
522	np = vfs_export_lookup(mp, nam);
523	if (np == NULL) {
524		lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
525		*credanonp = NULL;
526		return (EACCES);
527	}
528	*extflagsp = np->netc_exflags;
529	if ((*credanonp = np->netc_anon) != NULL)
530		crhold(*credanonp);
531	if (numsecflavors) {
532		*numsecflavors = np->netc_numsecflavors;
533		KASSERT(*numsecflavors > 0,
534		    ("%s: numsecflavors <= 0", __func__));
535		KASSERT(*numsecflavors < MAXSECFLAVORS,
536		    ("%s: numsecflavors >= MAXSECFLAVORS", __func__));
537	}
538	if (secflavors && np->netc_numsecflavors > 0)
539		memcpy(secflavors, np->netc_secflavors, np->netc_numsecflavors *
540		    sizeof(int));
541	lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
542	return (0);
543}
544