FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_export.c
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 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)vfs_subr.c 8.31 (Berkeley) 5/26/95
35 */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD: releng/9.1/sys/kern/vfs_export.c 253693 2013-07-26 22:40:23Z delphij $");
39
40 #include <sys/param.h>
41 #include <sys/dirent.h>
42 #include <sys/domain.h>
43 #include <sys/jail.h>
44 #include <sys/kernel.h>
45 #include <sys/lock.h>
46 #include <sys/malloc.h>
47 #include <sys/mbuf.h>
48 #include <sys/mount.h>
49 #include <sys/mutex.h>
50 #include <sys/rwlock.h>
51 #include <sys/refcount.h>
52 #include <sys/socket.h>
53 #include <sys/systm.h>
54 #include <sys/vnode.h>
55
56 #include <net/radix.h>
57
58 static MALLOC_DEFINE(M_NETADDR, "export_host", "Export host address structure");
59
60 static void vfs_free_addrlist(struct netexport *nep);
61 static int vfs_free_netcred(struct radix_node *rn, void *w);
62 static int vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
63 struct export_args *argp);
64 static struct netcred *vfs_export_lookup(struct mount *, struct sockaddr *);
65
66 /*
67 * Network address lookup element
68 */
69 struct netcred {
70 struct radix_node netc_rnodes[2];
71 int netc_exflags;
72 struct ucred *netc_anon;
73 int netc_numsecflavors;
74 int netc_secflavors[MAXSECFLAVORS];
75 };
76
77 /*
78 * Network export information
79 */
80 struct netexport {
81 struct netcred ne_defexported; /* Default export */
82 struct radix_node_head *ne_rtable[AF_MAX+1]; /* Individual exports */
83 };
84
85 /*
86 * Build hash lists of net addresses and hang them off the mount point.
87 * Called by vfs_export() to set up the lists of export addresses.
88 */
89 static int
90 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
91 struct export_args *argp)
92 {
93 register struct netcred *np;
94 register struct radix_node_head *rnh;
95 register int i;
96 struct radix_node *rn;
97 struct sockaddr *saddr, *smask = 0;
98 struct domain *dom;
99 int error;
100
101 /*
102 * XXX: This routine converts from a `struct xucred'
103 * (argp->ex_anon) to a `struct ucred' (np->netc_anon). This
104 * operation is questionable; for example, what should be done
105 * with fields like cr_uidinfo and cr_prison? Currently, this
106 * routine does not touch them (leaves them as NULL).
107 */
108 if (argp->ex_anon.cr_version != XUCRED_VERSION) {
109 vfs_mount_error(mp, "ex_anon.cr_version: %d != %d",
110 argp->ex_anon.cr_version, XUCRED_VERSION);
111 return (EINVAL);
112 }
113
114 if (argp->ex_addrlen == 0) {
115 if (mp->mnt_flag & MNT_DEFEXPORTED) {
116 vfs_mount_error(mp,
117 "MNT_DEFEXPORTED already set for mount %p", mp);
118 return (EPERM);
119 }
120 np = &nep->ne_defexported;
121 np->netc_exflags = argp->ex_flags;
122 np->netc_anon = crget();
123 np->netc_anon->cr_uid = argp->ex_anon.cr_uid;
124 crsetgroups(np->netc_anon, argp->ex_anon.cr_ngroups,
125 argp->ex_anon.cr_groups);
126 np->netc_anon->cr_prison = &prison0;
127 prison_hold(np->netc_anon->cr_prison);
128 np->netc_numsecflavors = argp->ex_numsecflavors;
129 bcopy(argp->ex_secflavors, np->netc_secflavors,
130 sizeof(np->netc_secflavors));
131 MNT_ILOCK(mp);
132 mp->mnt_flag |= MNT_DEFEXPORTED;
133 MNT_IUNLOCK(mp);
134 return (0);
135 }
136
137 #if MSIZE <= 256
138 if (argp->ex_addrlen > MLEN) {
139 vfs_mount_error(mp, "ex_addrlen %d is greater than %d",
140 argp->ex_addrlen, MLEN);
141 return (EINVAL);
142 }
143 #endif
144
145 i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
146 np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
147 saddr = (struct sockaddr *) (np + 1);
148 if ((error = copyin(argp->ex_addr, saddr, argp->ex_addrlen)))
149 goto out;
150 if (saddr->sa_family == AF_UNSPEC || saddr->sa_family > AF_MAX) {
151 error = EINVAL;
152 vfs_mount_error(mp, "Invalid saddr->sa_family: %d");
153 goto out;
154 }
155 if (saddr->sa_len > argp->ex_addrlen)
156 saddr->sa_len = argp->ex_addrlen;
157 if (argp->ex_masklen) {
158 smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
159 error = copyin(argp->ex_mask, smask, argp->ex_masklen);
160 if (error)
161 goto out;
162 if (smask->sa_len > argp->ex_masklen)
163 smask->sa_len = argp->ex_masklen;
164 }
165 i = saddr->sa_family;
166 if ((rnh = nep->ne_rtable[i]) == NULL) {
167 /*
168 * Seems silly to initialize every AF when most are not used,
169 * do so on demand here
170 */
171 for (dom = domains; dom; dom = dom->dom_next) {
172 KASSERT(((i == AF_INET) || (i == AF_INET6)),
173 ("unexpected protocol in vfs_hang_addrlist"));
174 if (dom->dom_family == i && dom->dom_rtattach) {
175 /*
176 * XXX MRT
177 * The INET and INET6 domains know the
178 * offset already. We don't need to send it
179 * So we just use it as a flag to say that
180 * we are or are not setting up a real routing
181 * table. Only IP and IPV6 need have this
182 * be 0 so all other protocols can stay the
183 * same (ABI compatible).
184 */
185 dom->dom_rtattach(
186 (void **) &nep->ne_rtable[i], 0);
187 break;
188 }
189 }
190 if ((rnh = nep->ne_rtable[i]) == NULL) {
191 error = ENOBUFS;
192 vfs_mount_error(mp, "%s %s %d",
193 "Unable to initialize radix node head ",
194 "for address family", i);
195 goto out;
196 }
197 }
198 RADIX_NODE_HEAD_LOCK(rnh);
199 rn = (*rnh->rnh_addaddr)(saddr, smask, rnh, np->netc_rnodes);
200 RADIX_NODE_HEAD_UNLOCK(rnh);
201 if (rn == NULL || np != (struct netcred *)rn) { /* already exists */
202 error = EPERM;
203 vfs_mount_error(mp, "Invalid radix node head, rn: %p %p",
204 rn, np);
205 goto out;
206 }
207 np->netc_exflags = argp->ex_flags;
208 np->netc_anon = crget();
209 np->netc_anon->cr_uid = argp->ex_anon.cr_uid;
210 crsetgroups(np->netc_anon, argp->ex_anon.cr_ngroups,
211 argp->ex_anon.cr_groups);
212 np->netc_anon->cr_prison = &prison0;
213 prison_hold(np->netc_anon->cr_prison);
214 np->netc_numsecflavors = argp->ex_numsecflavors;
215 bcopy(argp->ex_secflavors, np->netc_secflavors,
216 sizeof(np->netc_secflavors));
217 return (0);
218 out:
219 free(np, M_NETADDR);
220 return (error);
221 }
222
223 /* Helper for vfs_free_addrlist. */
224 /* ARGSUSED */
225 static int
226 vfs_free_netcred(struct radix_node *rn, void *w)
227 {
228 struct radix_node_head *rnh = (struct radix_node_head *) w;
229 struct ucred *cred;
230
231 (*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
232 cred = ((struct netcred *)rn)->netc_anon;
233 if (cred != NULL)
234 crfree(cred);
235 free(rn, M_NETADDR);
236 return (0);
237 }
238
239 /*
240 * Free the net address hash lists that are hanging off the mount points.
241 */
242 static void
243 vfs_free_addrlist(struct netexport *nep)
244 {
245 int i;
246 struct radix_node_head *rnh;
247 struct ucred *cred;
248
249 for (i = 0; i <= AF_MAX; i++) {
250 if ((rnh = nep->ne_rtable[i])) {
251 RADIX_NODE_HEAD_LOCK(rnh);
252 (*rnh->rnh_walktree) (rnh, vfs_free_netcred, rnh);
253 RADIX_NODE_HEAD_UNLOCK(rnh);
254 RADIX_NODE_HEAD_DESTROY(rnh);
255 free(rnh, M_RTABLE);
256 nep->ne_rtable[i] = NULL; /* not SMP safe XXX */
257 }
258 }
259 cred = nep->ne_defexported.netc_anon;
260 if (cred != NULL)
261 crfree(cred);
262
263 }
264
265 /*
266 * High level function to manipulate export options on a mount point
267 * and the passed in netexport.
268 * Struct export_args *argp is the variable used to twiddle options,
269 * the structure is described in sys/mount.h
270 */
271 int
272 vfs_export(struct mount *mp, struct export_args *argp)
273 {
274 struct netexport *nep;
275 int error;
276
277 if (argp->ex_numsecflavors < 0
278 || argp->ex_numsecflavors >= MAXSECFLAVORS)
279 return (EINVAL);
280
281 error = 0;
282 lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
283 nep = mp->mnt_export;
284 if (argp->ex_flags & MNT_DELEXPORT) {
285 if (nep == NULL) {
286 error = ENOENT;
287 goto out;
288 }
289 if (mp->mnt_flag & MNT_EXPUBLIC) {
290 vfs_setpublicfs(NULL, NULL, NULL);
291 MNT_ILOCK(mp);
292 mp->mnt_flag &= ~MNT_EXPUBLIC;
293 MNT_IUNLOCK(mp);
294 }
295 vfs_free_addrlist(nep);
296 mp->mnt_export = NULL;
297 free(nep, M_MOUNT);
298 nep = NULL;
299 MNT_ILOCK(mp);
300 mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
301 MNT_IUNLOCK(mp);
302 }
303 if (argp->ex_flags & MNT_EXPORTED) {
304 if (nep == NULL) {
305 nep = malloc(sizeof(struct netexport), M_MOUNT, M_WAITOK | M_ZERO);
306 mp->mnt_export = nep;
307 }
308 if (argp->ex_flags & MNT_EXPUBLIC) {
309 if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
310 goto out;
311 MNT_ILOCK(mp);
312 mp->mnt_flag |= MNT_EXPUBLIC;
313 MNT_IUNLOCK(mp);
314 }
315 if ((error = vfs_hang_addrlist(mp, nep, argp)))
316 goto out;
317 MNT_ILOCK(mp);
318 mp->mnt_flag |= MNT_EXPORTED;
319 MNT_IUNLOCK(mp);
320 }
321
322 out:
323 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
324 /*
325 * Once we have executed the vfs_export() command, we do
326 * not want to keep the "export" option around in the
327 * options list, since that will cause subsequent MNT_UPDATE
328 * calls to fail. The export information is saved in
329 * mp->mnt_export, so we can safely delete the "export" mount option
330 * here.
331 */
332 vfs_deleteopt(mp->mnt_optnew, "export");
333 vfs_deleteopt(mp->mnt_opt, "export");
334 return (error);
335 }
336
337 /*
338 * Set the publicly exported filesystem (WebNFS). Currently, only
339 * one public filesystem is possible in the spec (RFC 2054 and 2055)
340 */
341 int
342 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
343 struct export_args *argp)
344 {
345 int error;
346 struct vnode *rvp;
347 char *cp;
348
349 /*
350 * mp == NULL -> invalidate the current info, the FS is
351 * no longer exported. May be called from either vfs_export
352 * or unmount, so check if it hasn't already been done.
353 */
354 if (mp == NULL) {
355 if (nfs_pub.np_valid) {
356 nfs_pub.np_valid = 0;
357 if (nfs_pub.np_index != NULL) {
358 free(nfs_pub.np_index, M_TEMP);
359 nfs_pub.np_index = NULL;
360 }
361 }
362 return (0);
363 }
364
365 /*
366 * Only one allowed at a time.
367 */
368 if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
369 return (EBUSY);
370
371 /*
372 * Get real filehandle for root of exported FS.
373 */
374 bzero(&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
375 nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
376
377 if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rvp)))
378 return (error);
379
380 if ((error = VOP_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
381 return (error);
382
383 vput(rvp);
384
385 /*
386 * If an indexfile was specified, pull it in.
387 */
388 if (argp->ex_indexfile != NULL) {
389 if (nfs_pub.np_index != NULL)
390 nfs_pub.np_index = malloc(MAXNAMLEN + 1, M_TEMP,
391 M_WAITOK);
392 error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
393 MAXNAMLEN, (size_t *)0);
394 if (!error) {
395 /*
396 * Check for illegal filenames.
397 */
398 for (cp = nfs_pub.np_index; *cp; cp++) {
399 if (*cp == '/') {
400 error = EINVAL;
401 break;
402 }
403 }
404 }
405 if (error) {
406 free(nfs_pub.np_index, M_TEMP);
407 nfs_pub.np_index = NULL;
408 return (error);
409 }
410 }
411
412 nfs_pub.np_mount = mp;
413 nfs_pub.np_valid = 1;
414 return (0);
415 }
416
417 /*
418 * Used by the filesystems to determine if a given network address
419 * (passed in 'nam') is present in their exports list, returns a pointer
420 * to struct netcred so that the filesystem can examine it for
421 * access rights (read/write/etc).
422 */
423 static struct netcred *
424 vfs_export_lookup(struct mount *mp, struct sockaddr *nam)
425 {
426 struct netexport *nep;
427 register struct netcred *np;
428 register struct radix_node_head *rnh;
429 struct sockaddr *saddr;
430
431 nep = mp->mnt_export;
432 if (nep == NULL)
433 return (NULL);
434 np = NULL;
435 if (mp->mnt_flag & MNT_EXPORTED) {
436 /*
437 * Lookup in the export list first.
438 */
439 if (nam != NULL) {
440 saddr = nam;
441 rnh = nep->ne_rtable[saddr->sa_family];
442 if (rnh != NULL) {
443 RADIX_NODE_HEAD_RLOCK(rnh);
444 np = (struct netcred *)
445 (*rnh->rnh_matchaddr)(saddr, rnh);
446 RADIX_NODE_HEAD_RUNLOCK(rnh);
447 if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
448 np = NULL;
449 }
450 }
451 /*
452 * If no address match, use the default if it exists.
453 */
454 if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
455 np = &nep->ne_defexported;
456 }
457 return (np);
458 }
459
460 /*
461 * XXX: This comment comes from the deprecated ufs_check_export()
462 * XXX: and may not entirely apply, but lacking something better:
463 * This is the generic part of fhtovp called after the underlying
464 * filesystem has validated the file handle.
465 *
466 * Verify that a host should have access to a filesystem.
467 */
468
469 int
470 vfs_stdcheckexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
471 struct ucred **credanonp, int *numsecflavors, int **secflavors)
472 {
473 struct netcred *np;
474
475 lockmgr(&mp->mnt_explock, LK_SHARED, NULL);
476 np = vfs_export_lookup(mp, nam);
477 if (np == NULL) {
478 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
479 *credanonp = NULL;
480 return (EACCES);
481 }
482 *extflagsp = np->netc_exflags;
483 if ((*credanonp = np->netc_anon) != NULL)
484 crhold(*credanonp);
485 if (numsecflavors)
486 *numsecflavors = np->netc_numsecflavors;
487 if (secflavors)
488 *secflavors = np->netc_secflavors;
489 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
490 return (0);
491 }
492
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