xref: /freebsd/sys/kern/vfs_export.c (revision f9218d3d4fd34f082473b3a021c6d4d109fb47cf)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
39  * $FreeBSD$
40  */
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/socket.h>
46 #include <sys/malloc.h>
47 #include <sys/mbuf.h>
48 #include <sys/mount.h>
49 #include <net/radix.h>
50 #include <sys/domain.h>
51 #include <sys/dirent.h>
52 #include <sys/vnode.h>
53 
54 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
55 
56 static void	vfs_free_addrlist(struct netexport *nep);
57 static int	vfs_free_netcred(struct radix_node *rn, void *w);
58 static int	vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
59 		    struct export_args *argp);
60 
61 /*
62  * Network address lookup element
63  */
64 struct netcred {
65 	struct	radix_node netc_rnodes[2];
66 	int	netc_exflags;
67 	struct	ucred netc_anon;
68 };
69 
70 /*
71  * Network export information
72  */
73 struct netexport {
74 	struct	netcred ne_defexported;		      /* Default export */
75 	struct	radix_node_head *ne_rtable[AF_MAX+1]; /* Individual exports */
76 };
77 
78 /*
79  * Build hash lists of net addresses and hang them off the mount point.
80  * Called by ufs_mount() to set up the lists of export addresses.
81  */
82 static int
83 vfs_hang_addrlist(mp, nep, argp)
84 	struct mount *mp;
85 	struct netexport *nep;
86 	struct export_args *argp;
87 {
88 	register struct netcred *np;
89 	register struct radix_node_head *rnh;
90 	register int i;
91 	struct radix_node *rn;
92 	struct sockaddr *saddr, *smask = 0;
93 	struct domain *dom;
94 	int error;
95 
96 	/*
97 	 * XXX: This routine converts from a `struct xucred'
98 	 * (argp->ex_anon) to a `struct ucred' (np->netc_anon).  This
99 	 * operation is questionable; for example, what should be done
100 	 * with fields like cr_uidinfo and cr_prison?  Currently, this
101 	 * routine does not touch them (leaves them as NULL).
102 	 */
103 	if (argp->ex_anon.cr_version != XUCRED_VERSION)
104 		return (EINVAL);
105 
106 	if (argp->ex_addrlen == 0) {
107 		if (mp->mnt_flag & MNT_DEFEXPORTED)
108 			return (EPERM);
109 		np = &nep->ne_defexported;
110 		np->netc_exflags = argp->ex_flags;
111 		bzero(&np->netc_anon, sizeof(np->netc_anon));
112 		np->netc_anon.cr_uid = argp->ex_anon.cr_uid;
113 		np->netc_anon.cr_ngroups = argp->ex_anon.cr_ngroups;
114 		bcopy(argp->ex_anon.cr_groups, np->netc_anon.cr_groups,
115 		    sizeof(np->netc_anon.cr_groups));
116 		np->netc_anon.cr_ref = 1;
117 		mp->mnt_flag |= MNT_DEFEXPORTED;
118 		return (0);
119 	}
120 
121 	if (argp->ex_addrlen > MLEN)
122 		return (EINVAL);
123 
124 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
125 	np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
126 	saddr = (struct sockaddr *) (np + 1);
127 	if ((error = copyin(argp->ex_addr, saddr, argp->ex_addrlen)))
128 		goto out;
129 	if (saddr->sa_len > argp->ex_addrlen)
130 		saddr->sa_len = argp->ex_addrlen;
131 	if (argp->ex_masklen) {
132 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
133 		error = copyin(argp->ex_mask, smask, argp->ex_masklen);
134 		if (error)
135 			goto out;
136 		if (smask->sa_len > argp->ex_masklen)
137 			smask->sa_len = argp->ex_masklen;
138 	}
139 	i = saddr->sa_family;
140 	if ((rnh = nep->ne_rtable[i]) == NULL) {
141 		/*
142 		 * Seems silly to initialize every AF when most are not used,
143 		 * do so on demand here
144 		 */
145 		for (dom = domains; dom; dom = dom->dom_next)
146 			if (dom->dom_family == i && dom->dom_rtattach) {
147 				dom->dom_rtattach((void **) &nep->ne_rtable[i],
148 				    dom->dom_rtoffset);
149 				break;
150 			}
151 		if ((rnh = nep->ne_rtable[i]) == NULL) {
152 			error = ENOBUFS;
153 			goto out;
154 		}
155 	}
156 	RADIX_NODE_HEAD_LOCK(rnh);
157 	rn = (*rnh->rnh_addaddr)(saddr, smask, rnh, np->netc_rnodes);
158 	RADIX_NODE_HEAD_UNLOCK(rnh);
159 	if (rn == NULL || np != (struct netcred *)rn) {	/* already exists */
160 		error = EPERM;
161 		goto out;
162 	}
163 	np->netc_exflags = argp->ex_flags;
164 	bzero(&np->netc_anon, sizeof(np->netc_anon));
165 	np->netc_anon.cr_uid = argp->ex_anon.cr_uid;
166 	np->netc_anon.cr_ngroups = argp->ex_anon.cr_ngroups;
167 	bcopy(argp->ex_anon.cr_groups, np->netc_anon.cr_groups,
168 	    sizeof(np->netc_anon.cr_groups));
169 	np->netc_anon.cr_ref = 1;
170 	return (0);
171 out:
172 	free(np, M_NETADDR);
173 	return (error);
174 }
175 
176 /* Helper for vfs_free_addrlist. */
177 /* ARGSUSED */
178 static int
179 vfs_free_netcred(rn, w)
180 	struct radix_node *rn;
181 	void *w;
182 {
183 	register struct radix_node_head *rnh = (struct radix_node_head *) w;
184 
185 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
186 	free(rn, M_NETADDR);
187 	return (0);
188 }
189 
190 /*
191  * Free the net address hash lists that are hanging off the mount points.
192  */
193 static void
194 vfs_free_addrlist(nep)
195 	struct netexport *nep;
196 {
197 	register int i;
198 	register struct radix_node_head *rnh;
199 
200 	for (i = 0; i <= AF_MAX; i++)
201 		if ((rnh = nep->ne_rtable[i])) {
202 			RADIX_NODE_HEAD_LOCK(rnh);
203 			(*rnh->rnh_walktree) (rnh, vfs_free_netcred, rnh);
204 			RADIX_NODE_HEAD_DESTROY(rnh);
205 			free(rnh, M_RTABLE);
206 			nep->ne_rtable[i] = NULL;	/* not SMP safe XXX */
207 		}
208 }
209 
210 /*
211  * High level function to manipulate export options on a mount point
212  * and the passed in netexport.
213  * Struct export_args *argp is the variable used to twiddle options,
214  * the structure is described in sys/mount.h
215  */
216 int
217 vfs_export(mp, argp)
218 	struct mount *mp;
219 	struct export_args *argp;
220 {
221 	struct netexport *nep;
222 	int error;
223 
224 	nep = mp->mnt_export;
225 	if (argp->ex_flags & MNT_DELEXPORT) {
226 		if (nep == NULL)
227 			return (ENOENT);
228 		if (mp->mnt_flag & MNT_EXPUBLIC) {
229 			vfs_setpublicfs(NULL, NULL, NULL);
230 			mp->mnt_flag &= ~MNT_EXPUBLIC;
231 		}
232 		vfs_free_addrlist(nep);
233 		mp->mnt_export = NULL;
234 		free(nep, M_MOUNT);
235 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
236 	}
237 	if (argp->ex_flags & MNT_EXPORTED) {
238 		if (nep == NULL) {
239 			nep = malloc(sizeof(struct netexport), M_MOUNT, M_WAITOK | M_ZERO);
240 			mp->mnt_export = nep;
241 		}
242 		if (argp->ex_flags & MNT_EXPUBLIC) {
243 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
244 				return (error);
245 			mp->mnt_flag |= MNT_EXPUBLIC;
246 		}
247 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
248 			return (error);
249 		mp->mnt_flag |= MNT_EXPORTED;
250 	}
251 	return (0);
252 }
253 
254 /*
255  * Set the publicly exported filesystem (WebNFS). Currently, only
256  * one public filesystem is possible in the spec (RFC 2054 and 2055)
257  */
258 int
259 vfs_setpublicfs(mp, nep, argp)
260 	struct mount *mp;
261 	struct netexport *nep;
262 	struct export_args *argp;
263 {
264 	int error;
265 	struct vnode *rvp;
266 	char *cp;
267 
268 	/*
269 	 * mp == NULL -> invalidate the current info, the FS is
270 	 * no longer exported. May be called from either vfs_export
271 	 * or unmount, so check if it hasn't already been done.
272 	 */
273 	if (mp == NULL) {
274 		if (nfs_pub.np_valid) {
275 			nfs_pub.np_valid = 0;
276 			if (nfs_pub.np_index != NULL) {
277 				FREE(nfs_pub.np_index, M_TEMP);
278 				nfs_pub.np_index = NULL;
279 			}
280 		}
281 		return (0);
282 	}
283 
284 	/*
285 	 * Only one allowed at a time.
286 	 */
287 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
288 		return (EBUSY);
289 
290 	/*
291 	 * Get real filehandle for root of exported FS.
292 	 */
293 	bzero(&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
294 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
295 
296 	if ((error = VFS_ROOT(mp, &rvp)))
297 		return (error);
298 
299 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
300 		return (error);
301 
302 	vput(rvp);
303 
304 	/*
305 	 * If an indexfile was specified, pull it in.
306 	 */
307 	if (argp->ex_indexfile != NULL) {
308 		MALLOC(nfs_pub.np_index, char *, MAXNAMLEN + 1, M_TEMP,
309 		    M_WAITOK);
310 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
311 		    MAXNAMLEN, (size_t *)0);
312 		if (!error) {
313 			/*
314 			 * Check for illegal filenames.
315 			 */
316 			for (cp = nfs_pub.np_index; *cp; cp++) {
317 				if (*cp == '/') {
318 					error = EINVAL;
319 					break;
320 				}
321 			}
322 		}
323 		if (error) {
324 			FREE(nfs_pub.np_index, M_TEMP);
325 			return (error);
326 		}
327 	}
328 
329 	nfs_pub.np_mount = mp;
330 	nfs_pub.np_valid = 1;
331 	return (0);
332 }
333 
334 /*
335  * Used by the filesystems to determine if a given network address
336  * (passed in 'nam') is present in thier exports list, returns a pointer
337  * to struct netcred so that the filesystem can examine it for
338  * access rights (read/write/etc).
339  */
340 struct netcred *
341 vfs_export_lookup(mp, nam)
342 	register struct mount *mp;
343 	struct sockaddr *nam;
344 {
345 	struct netexport *nep;
346 	register struct netcred *np;
347 	register struct radix_node_head *rnh;
348 	struct sockaddr *saddr;
349 
350 	nep = mp->mnt_export;
351 	if (nep == NULL)
352 		return (NULL);
353 	np = NULL;
354 	if (mp->mnt_flag & MNT_EXPORTED) {
355 		/*
356 		 * Lookup in the export list first.
357 		 */
358 		if (nam != NULL) {
359 			saddr = nam;
360 			rnh = nep->ne_rtable[saddr->sa_family];
361 			if (rnh != NULL) {
362 				RADIX_NODE_HEAD_LOCK(rnh);
363 				np = (struct netcred *)
364 				    (*rnh->rnh_matchaddr)(saddr, rnh);
365 				RADIX_NODE_HEAD_UNLOCK(rnh);
366 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
367 					np = NULL;
368 			}
369 		}
370 		/*
371 		 * If no address match, use the default if it exists.
372 		 */
373 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
374 			np = &nep->ne_defexported;
375 	}
376 	return (np);
377 }
378 
379 /*
380  * XXX: This comment comes from the deprecated ufs_check_export()
381  * XXX: and may not entirely apply, but lacking something better:
382  * This is the generic part of fhtovp called after the underlying
383  * filesystem has validated the file handle.
384  *
385  * Verify that a host should have access to a filesystem.
386  */
387 
388 int
389 vfs_stdcheckexp(mp, nam, extflagsp, credanonp)
390 	struct mount *mp;
391 	struct sockaddr *nam;
392 	int *extflagsp;
393 	struct ucred **credanonp;
394 {
395 	struct netcred *np;
396 
397 	np = vfs_export_lookup(mp, nam);
398 	if (np == NULL)
399 		return (EACCES);
400 	*extflagsp = np->netc_exflags;
401 	*credanonp = &np->netc_anon;
402 	return (0);
403 }
404 
405