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: stable/12/sys/kern/vfs_export.c 362375 2020-06-19 11:45:12Z freqlabs $");
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
67 static MALLOC_DEFINE(M_NETADDR, "export_host", "Export host address structure");
68
69 #if defined(INET) || defined(INET6)
70 static struct radix_node_head *vfs_create_addrlist_af(
71 struct radix_node_head **prnh, int off);
72 #endif
73 static void vfs_free_addrlist(struct netexport *nep);
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 int 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
vfs_hang_addrlist(struct mount * mp,struct netexport * nep,struct export_args * argp)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 `struct xucred'
125 * (argp->ex_anon) 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_anon.cr_version != XUCRED_VERSION) {
131 vfs_mount_error(mp, "ex_anon.cr_version: %d != %d",
132 argp->ex_anon.cr_version, XUCRED_VERSION);
133 return (EINVAL);
134 }
135
136 if (argp->ex_addrlen == 0) {
137 if (mp->mnt_flag & MNT_DEFEXPORTED) {
138 vfs_mount_error(mp,
139 "MNT_DEFEXPORTED already set for mount %p", mp);
140 return (EPERM);
141 }
142 np = &nep->ne_defexported;
143 np->netc_exflags = argp->ex_flags;
144 np->netc_anon = crget();
145 np->netc_anon->cr_uid = argp->ex_anon.cr_uid;
146 crsetgroups(np->netc_anon, argp->ex_anon.cr_ngroups,
147 argp->ex_anon.cr_groups);
148 np->netc_anon->cr_prison = &prison0;
149 prison_hold(np->netc_anon->cr_prison);
150 np->netc_numsecflavors = argp->ex_numsecflavors;
151 bcopy(argp->ex_secflavors, np->netc_secflavors,
152 sizeof(np->netc_secflavors));
153 MNT_ILOCK(mp);
154 mp->mnt_flag |= MNT_DEFEXPORTED;
155 MNT_IUNLOCK(mp);
156 return (0);
157 }
158
159 #if MSIZE <= 256
160 if (argp->ex_addrlen > MLEN) {
161 vfs_mount_error(mp, "ex_addrlen %d is greater than %d",
162 argp->ex_addrlen, MLEN);
163 return (EINVAL);
164 }
165 #endif
166
167 i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
168 np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
169 saddr = (struct sockaddr *) (np + 1);
170 if ((error = copyin(argp->ex_addr, saddr, argp->ex_addrlen)))
171 goto out;
172 if (saddr->sa_family == AF_UNSPEC || saddr->sa_family > AF_MAX) {
173 error = EINVAL;
174 vfs_mount_error(mp, "Invalid saddr->sa_family: %d");
175 goto out;
176 }
177 if (saddr->sa_len > argp->ex_addrlen)
178 saddr->sa_len = argp->ex_addrlen;
179 if (argp->ex_masklen) {
180 smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
181 error = copyin(argp->ex_mask, smask, argp->ex_masklen);
182 if (error)
183 goto out;
184 if (smask->sa_len > argp->ex_masklen)
185 smask->sa_len = argp->ex_masklen;
186 }
187 rnh = NULL;
188 switch (saddr->sa_family) {
189 #ifdef INET
190 case AF_INET:
191 if ((rnh = nep->ne4) == NULL) {
192 off = offsetof(struct sockaddr_in, sin_addr) << 3;
193 rnh = vfs_create_addrlist_af(&nep->ne4, off);
194 }
195 break;
196 #endif
197 #ifdef INET6
198 case AF_INET6:
199 if ((rnh = nep->ne6) == NULL) {
200 off = offsetof(struct sockaddr_in6, sin6_addr) << 3;
201 rnh = vfs_create_addrlist_af(&nep->ne6, off);
202 }
203 break;
204 #endif
205 }
206 if (rnh == NULL) {
207 error = ENOBUFS;
208 vfs_mount_error(mp, "%s %s %d",
209 "Unable to initialize radix node head ",
210 "for address family", saddr->sa_family);
211 goto out;
212 }
213 RADIX_NODE_HEAD_LOCK(rnh);
214 rn = (*rnh->rnh_addaddr)(saddr, smask, &rnh->rh, np->netc_rnodes);
215 RADIX_NODE_HEAD_UNLOCK(rnh);
216 if (rn == NULL || np != (struct netcred *)rn) { /* already exists */
217 error = EPERM;
218 vfs_mount_error(mp,
219 "netcred already exists for given addr/mask");
220 goto out;
221 }
222 np->netc_exflags = argp->ex_flags;
223 np->netc_anon = crget();
224 np->netc_anon->cr_uid = argp->ex_anon.cr_uid;
225 crsetgroups(np->netc_anon, argp->ex_anon.cr_ngroups,
226 argp->ex_anon.cr_groups);
227 np->netc_anon->cr_prison = &prison0;
228 prison_hold(np->netc_anon->cr_prison);
229 np->netc_numsecflavors = argp->ex_numsecflavors;
230 bcopy(argp->ex_secflavors, np->netc_secflavors,
231 sizeof(np->netc_secflavors));
232 return (0);
233 out:
234 free(np, M_NETADDR);
235 return (error);
236 }
237
238 /* Helper for vfs_free_addrlist. */
239 /* ARGSUSED */
240 static int
vfs_free_netcred(struct radix_node * rn,void * w)241 vfs_free_netcred(struct radix_node *rn, void *w)
242 {
243 struct radix_node_head *rnh = (struct radix_node_head *) w;
244 struct ucred *cred;
245
246 (*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, &rnh->rh);
247 cred = ((struct netcred *)rn)->netc_anon;
248 if (cred != NULL)
249 crfree(cred);
250 free(rn, M_NETADDR);
251 return (0);
252 }
253
254 #if defined(INET) || defined(INET6)
255 static struct radix_node_head *
vfs_create_addrlist_af(struct radix_node_head ** prnh,int off)256 vfs_create_addrlist_af(struct radix_node_head **prnh, int off)
257 {
258
259 if (rn_inithead((void **)prnh, off) == 0)
260 return (NULL);
261 RADIX_NODE_HEAD_LOCK_INIT(*prnh);
262 return (*prnh);
263 }
264 #endif
265
266 static void
vfs_free_addrlist_af(struct radix_node_head ** prnh)267 vfs_free_addrlist_af(struct radix_node_head **prnh)
268 {
269 struct radix_node_head *rnh;
270
271 rnh = *prnh;
272 RADIX_NODE_HEAD_LOCK(rnh);
273 (*rnh->rnh_walktree)(&rnh->rh, vfs_free_netcred, rnh);
274 RADIX_NODE_HEAD_UNLOCK(rnh);
275 RADIX_NODE_HEAD_DESTROY(rnh);
276 rn_detachhead((void **)prnh);
277 prnh = NULL;
278 }
279
280 /*
281 * Free the net address hash lists that are hanging off the mount points.
282 */
283 static void
vfs_free_addrlist(struct netexport * nep)284 vfs_free_addrlist(struct netexport *nep)
285 {
286 struct ucred *cred;
287
288 if (nep->ne4 != NULL)
289 vfs_free_addrlist_af(&nep->ne4);
290 if (nep->ne6 != NULL)
291 vfs_free_addrlist_af(&nep->ne6);
292
293 cred = nep->ne_defexported.netc_anon;
294 if (cred != NULL)
295 crfree(cred);
296
297 }
298
299 /*
300 * High level function to manipulate export options on a mount point
301 * and the passed in netexport.
302 * Struct export_args *argp is the variable used to twiddle options,
303 * the structure is described in sys/mount.h
304 */
305 int
vfs_export(struct mount * mp,struct export_args * argp)306 vfs_export(struct mount *mp, struct export_args *argp)
307 {
308 struct netexport *nep;
309 int error;
310
311 if ((argp->ex_flags & (MNT_DELEXPORT | MNT_EXPORTED)) == 0)
312 return (EINVAL);
313
314 if ((argp->ex_flags & MNT_EXPORTED) != 0 &&
315 (argp->ex_numsecflavors < 0
316 || argp->ex_numsecflavors >= MAXSECFLAVORS))
317 return (EINVAL);
318
319 error = 0;
320 lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
321 nep = mp->mnt_export;
322 if (argp->ex_flags & MNT_DELEXPORT) {
323 if (nep == NULL) {
324 error = ENOENT;
325 goto out;
326 }
327 if (mp->mnt_flag & MNT_EXPUBLIC) {
328 vfs_setpublicfs(NULL, NULL, NULL);
329 MNT_ILOCK(mp);
330 mp->mnt_flag &= ~MNT_EXPUBLIC;
331 MNT_IUNLOCK(mp);
332 }
333 vfs_free_addrlist(nep);
334 mp->mnt_export = NULL;
335 free(nep, M_MOUNT);
336 nep = NULL;
337 MNT_ILOCK(mp);
338 mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
339 MNT_IUNLOCK(mp);
340 }
341 if (argp->ex_flags & MNT_EXPORTED) {
342 if (nep == NULL) {
343 nep = malloc(sizeof(struct netexport), M_MOUNT, M_WAITOK | M_ZERO);
344 mp->mnt_export = nep;
345 }
346 if (argp->ex_flags & MNT_EXPUBLIC) {
347 if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
348 goto out;
349 MNT_ILOCK(mp);
350 mp->mnt_flag |= MNT_EXPUBLIC;
351 MNT_IUNLOCK(mp);
352 }
353 if (argp->ex_numsecflavors == 0) {
354 argp->ex_numsecflavors = 1;
355 argp->ex_secflavors[0] = AUTH_SYS;
356 }
357 if ((error = vfs_hang_addrlist(mp, nep, argp)))
358 goto out;
359 MNT_ILOCK(mp);
360 mp->mnt_flag |= MNT_EXPORTED;
361 MNT_IUNLOCK(mp);
362 }
363
364 out:
365 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
366 /*
367 * Once we have executed the vfs_export() command, we do
368 * not want to keep the "export" option around in the
369 * options list, since that will cause subsequent MNT_UPDATE
370 * calls to fail. The export information is saved in
371 * mp->mnt_export, so we can safely delete the "export" mount option
372 * here.
373 */
374 vfs_deleteopt(mp->mnt_optnew, "export");
375 vfs_deleteopt(mp->mnt_opt, "export");
376 return (error);
377 }
378
379 /*
380 * Set the publicly exported filesystem (WebNFS). Currently, only
381 * one public filesystem is possible in the spec (RFC 2054 and 2055)
382 */
383 int
vfs_setpublicfs(struct mount * mp,struct netexport * nep,struct export_args * argp)384 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
385 struct export_args *argp)
386 {
387 int error;
388 struct vnode *rvp;
389 char *cp;
390
391 /*
392 * mp == NULL -> invalidate the current info, the FS is
393 * no longer exported. May be called from either vfs_export
394 * or unmount, so check if it hasn't already been done.
395 */
396 if (mp == NULL) {
397 if (nfs_pub.np_valid) {
398 nfs_pub.np_valid = 0;
399 if (nfs_pub.np_index != NULL) {
400 free(nfs_pub.np_index, M_TEMP);
401 nfs_pub.np_index = NULL;
402 }
403 }
404 return (0);
405 }
406
407 /*
408 * Only one allowed at a time.
409 */
410 if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
411 return (EBUSY);
412
413 /*
414 * Get real filehandle for root of exported FS.
415 */
416 bzero(&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
417 nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
418
419 if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rvp)))
420 return (error);
421
422 if ((error = VOP_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
423 return (error);
424
425 vput(rvp);
426
427 /*
428 * If an indexfile was specified, pull it in.
429 */
430 if (argp->ex_indexfile != NULL) {
431 if (nfs_pub.np_index == NULL)
432 nfs_pub.np_index = malloc(MAXNAMLEN + 1, M_TEMP,
433 M_WAITOK);
434 error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
435 MAXNAMLEN, (size_t *)0);
436 if (!error) {
437 /*
438 * Check for illegal filenames.
439 */
440 for (cp = nfs_pub.np_index; *cp; cp++) {
441 if (*cp == '/') {
442 error = EINVAL;
443 break;
444 }
445 }
446 }
447 if (error) {
448 free(nfs_pub.np_index, M_TEMP);
449 nfs_pub.np_index = NULL;
450 return (error);
451 }
452 }
453
454 nfs_pub.np_mount = mp;
455 nfs_pub.np_valid = 1;
456 return (0);
457 }
458
459 /*
460 * Used by the filesystems to determine if a given network address
461 * (passed in 'nam') is present in their exports list, returns a pointer
462 * to struct netcred so that the filesystem can examine it for
463 * access rights (read/write/etc).
464 */
465 static struct netcred *
vfs_export_lookup(struct mount * mp,struct sockaddr * nam)466 vfs_export_lookup(struct mount *mp, struct sockaddr *nam)
467 {
468 RADIX_NODE_HEAD_RLOCK_TRACKER;
469 struct netexport *nep;
470 struct netcred *np = NULL;
471 struct radix_node_head *rnh;
472 struct sockaddr *saddr;
473
474 nep = mp->mnt_export;
475 if (nep == NULL)
476 return (NULL);
477 if ((mp->mnt_flag & MNT_EXPORTED) == 0)
478 return (NULL);
479
480 /*
481 * Lookup in the export list
482 */
483 if (nam != NULL) {
484 saddr = nam;
485 rnh = NULL;
486 switch (saddr->sa_family) {
487 case AF_INET:
488 rnh = nep->ne4;
489 break;
490 case AF_INET6:
491 rnh = nep->ne6;
492 break;
493 }
494 if (rnh != NULL) {
495 RADIX_NODE_HEAD_RLOCK(rnh);
496 np = (struct netcred *) (*rnh->rnh_matchaddr)(saddr, &rnh->rh);
497 RADIX_NODE_HEAD_RUNLOCK(rnh);
498 if (np != NULL && (np->netc_rnodes->rn_flags & RNF_ROOT) != 0)
499 return (NULL);
500 }
501 }
502
503 /*
504 * If no address match, use the default if it exists.
505 */
506 if (np == NULL && (mp->mnt_flag & MNT_DEFEXPORTED) != 0)
507 return (&nep->ne_defexported);
508
509 return (np);
510 }
511
512 /*
513 * XXX: This comment comes from the deprecated ufs_check_export()
514 * XXX: and may not entirely apply, but lacking something better:
515 * This is the generic part of fhtovp called after the underlying
516 * filesystem has validated the file handle.
517 *
518 * Verify that a host should have access to a filesystem.
519 */
520
521 int
vfs_stdcheckexp(struct mount * mp,struct sockaddr * nam,int * extflagsp,struct ucred ** credanonp,int * numsecflavors,int ** secflavors)522 vfs_stdcheckexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
523 struct ucred **credanonp, int *numsecflavors, int **secflavors)
524 {
525 struct netcred *np;
526
527 lockmgr(&mp->mnt_explock, LK_SHARED, NULL);
528 np = vfs_export_lookup(mp, nam);
529 if (np == NULL) {
530 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
531 *credanonp = NULL;
532 return (EACCES);
533 }
534 *extflagsp = np->netc_exflags;
535 if ((*credanonp = np->netc_anon) != NULL)
536 crhold(*credanonp);
537 if (numsecflavors) {
538 *numsecflavors = np->netc_numsecflavors;
539 KASSERT(*numsecflavors > 0,
540 ("%s: numsecflavors <= 0", __func__));
541 KASSERT(*numsecflavors < MAXSECFLAVORS,
542 ("%s: numsecflavors >= MAXSECFLAVORS", __func__));
543 }
544 if (secflavors)
545 *secflavors = np->netc_secflavors;
546 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
547 return (0);
548 }
549
550