Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_export.c
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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: releng/12.0/sys/kern/vfs_export.c 341085 2018-11-27 17:58:25Z markj $"); 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 static MALLOC_DEFINE(M_NETADDR, "export_host", "Export host address structure"); 65 66 #if defined(INET) || defined(INET6) 67 static struct radix_node_head *vfs_create_addrlist_af( 68 struct radix_node_head **prnh, int off); 69 #endif 70 static void vfs_free_addrlist(struct netexport *nep); 71 static int vfs_free_netcred(struct radix_node *rn, void *w); 72 static void vfs_free_addrlist_af(struct radix_node_head **prnh); 73 static int vfs_hang_addrlist(struct mount *mp, struct netexport *nep, 74 struct export_args *argp); 75 static struct netcred *vfs_export_lookup(struct mount *, struct sockaddr *); 76 77 /* 78 * Network address lookup element 79 */ 80 struct netcred { 81 struct radix_node netc_rnodes[2]; 82 int netc_exflags; 83 struct ucred *netc_anon; 84 int netc_numsecflavors; 85 int netc_secflavors[MAXSECFLAVORS]; 86 }; 87 88 /* 89 * Network export information 90 */ 91 struct netexport { 92 struct netcred ne_defexported; /* Default export */ 93 struct radix_node_head *ne4; 94 struct radix_node_head *ne6; 95 }; 96 97 /* 98 * Build hash lists of net addresses and hang them off the mount point. 99 * Called by vfs_export() to set up the lists of export addresses. 100 */ 101 static int 102 vfs_hang_addrlist(struct mount *mp, struct netexport *nep, 103 struct export_args *argp) 104 { 105 struct netcred *np; 106 struct radix_node_head *rnh; 107 int i; 108 struct radix_node *rn; 109 struct sockaddr *saddr, *smask = NULL; 110 #if defined(INET6) || defined(INET) 111 int off; 112 #endif 113 int error; 114 115 /* 116 * XXX: This routine converts from a `struct xucred' 117 * (argp->ex_anon) to a `struct ucred' (np->netc_anon). This 118 * operation is questionable; for example, what should be done 119 * with fields like cr_uidinfo and cr_prison? Currently, this 120 * routine does not touch them (leaves them as NULL). 121 */ 122 if (argp->ex_anon.cr_version != XUCRED_VERSION) { 123 vfs_mount_error(mp, "ex_anon.cr_version: %d != %d", 124 argp->ex_anon.cr_version, XUCRED_VERSION); 125 return (EINVAL); 126 } 127 128 if (argp->ex_addrlen == 0) { 129 if (mp->mnt_flag & MNT_DEFEXPORTED) { 130 vfs_mount_error(mp, 131 "MNT_DEFEXPORTED already set for mount %p", mp); 132 return (EPERM); 133 } 134 np = &nep->ne_defexported; 135 np->netc_exflags = argp->ex_flags; 136 np->netc_anon = crget(); 137 np->netc_anon->cr_uid = argp->ex_anon.cr_uid; 138 crsetgroups(np->netc_anon, argp->ex_anon.cr_ngroups, 139 argp->ex_anon.cr_groups); 140 np->netc_anon->cr_prison = &prison0; 141 prison_hold(np->netc_anon->cr_prison); 142 np->netc_numsecflavors = argp->ex_numsecflavors; 143 bcopy(argp->ex_secflavors, np->netc_secflavors, 144 sizeof(np->netc_secflavors)); 145 MNT_ILOCK(mp); 146 mp->mnt_flag |= MNT_DEFEXPORTED; 147 MNT_IUNLOCK(mp); 148 return (0); 149 } 150 151 #if MSIZE <= 256 152 if (argp->ex_addrlen > MLEN) { 153 vfs_mount_error(mp, "ex_addrlen %d is greater than %d", 154 argp->ex_addrlen, MLEN); 155 return (EINVAL); 156 } 157 #endif 158 159 i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen; 160 np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK | M_ZERO); 161 saddr = (struct sockaddr *) (np + 1); 162 if ((error = copyin(argp->ex_addr, saddr, argp->ex_addrlen))) 163 goto out; 164 if (saddr->sa_family == AF_UNSPEC || saddr->sa_family > AF_MAX) { 165 error = EINVAL; 166 vfs_mount_error(mp, "Invalid saddr->sa_family: %d"); 167 goto out; 168 } 169 if (saddr->sa_len > argp->ex_addrlen) 170 saddr->sa_len = argp->ex_addrlen; 171 if (argp->ex_masklen) { 172 smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen); 173 error = copyin(argp->ex_mask, smask, argp->ex_masklen); 174 if (error) 175 goto out; 176 if (smask->sa_len > argp->ex_masklen) 177 smask->sa_len = argp->ex_masklen; 178 } 179 rnh = NULL; 180 switch (saddr->sa_family) { 181 #ifdef INET 182 case AF_INET: 183 if ((rnh = nep->ne4) == NULL) { 184 off = offsetof(struct sockaddr_in, sin_addr) << 3; 185 rnh = vfs_create_addrlist_af(&nep->ne4, off); 186 } 187 break; 188 #endif 189 #ifdef INET6 190 case AF_INET6: 191 if ((rnh = nep->ne6) == NULL) { 192 off = offsetof(struct sockaddr_in6, sin6_addr) << 3; 193 rnh = vfs_create_addrlist_af(&nep->ne6, off); 194 } 195 break; 196 #endif 197 } 198 if (rnh == NULL) { 199 error = ENOBUFS; 200 vfs_mount_error(mp, "%s %s %d", 201 "Unable to initialize radix node head ", 202 "for address family", saddr->sa_family); 203 goto out; 204 } 205 RADIX_NODE_HEAD_LOCK(rnh); 206 rn = (*rnh->rnh_addaddr)(saddr, smask, &rnh->rh, np->netc_rnodes); 207 RADIX_NODE_HEAD_UNLOCK(rnh); 208 if (rn == NULL || np != (struct netcred *)rn) { /* already exists */ 209 error = EPERM; 210 vfs_mount_error(mp, 211 "netcred already exists for given addr/mask"); 212 goto out; 213 } 214 np->netc_exflags = argp->ex_flags; 215 np->netc_anon = crget(); 216 np->netc_anon->cr_uid = argp->ex_anon.cr_uid; 217 crsetgroups(np->netc_anon, argp->ex_anon.cr_ngroups, 218 argp->ex_anon.cr_groups); 219 np->netc_anon->cr_prison = &prison0; 220 prison_hold(np->netc_anon->cr_prison); 221 np->netc_numsecflavors = argp->ex_numsecflavors; 222 bcopy(argp->ex_secflavors, np->netc_secflavors, 223 sizeof(np->netc_secflavors)); 224 return (0); 225 out: 226 free(np, M_NETADDR); 227 return (error); 228 } 229 230 /* Helper for vfs_free_addrlist. */ 231 /* ARGSUSED */ 232 static int 233 vfs_free_netcred(struct radix_node *rn, void *w) 234 { 235 struct radix_node_head *rnh = (struct radix_node_head *) w; 236 struct ucred *cred; 237 238 (*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, &rnh->rh); 239 cred = ((struct netcred *)rn)->netc_anon; 240 if (cred != NULL) 241 crfree(cred); 242 free(rn, M_NETADDR); 243 return (0); 244 } 245 246 #if defined(INET) || defined(INET6) 247 static struct radix_node_head * 248 vfs_create_addrlist_af(struct radix_node_head **prnh, int off) 249 { 250 251 if (rn_inithead((void **)prnh, off) == 0) 252 return (NULL); 253 RADIX_NODE_HEAD_LOCK_INIT(*prnh); 254 return (*prnh); 255 } 256 #endif 257 258 static void 259 vfs_free_addrlist_af(struct radix_node_head **prnh) 260 { 261 struct radix_node_head *rnh; 262 263 rnh = *prnh; 264 RADIX_NODE_HEAD_LOCK(rnh); 265 (*rnh->rnh_walktree)(&rnh->rh, vfs_free_netcred, rnh); 266 RADIX_NODE_HEAD_UNLOCK(rnh); 267 RADIX_NODE_HEAD_DESTROY(rnh); 268 rn_detachhead((void **)prnh); 269 prnh = NULL; 270 } 271 272 /* 273 * Free the net address hash lists that are hanging off the mount points. 274 */ 275 static void 276 vfs_free_addrlist(struct netexport *nep) 277 { 278 struct ucred *cred; 279 280 if (nep->ne4 != NULL) 281 vfs_free_addrlist_af(&nep->ne4); 282 if (nep->ne6 != NULL) 283 vfs_free_addrlist_af(&nep->ne6); 284 285 cred = nep->ne_defexported.netc_anon; 286 if (cred != NULL) 287 crfree(cred); 288 289 } 290 291 /* 292 * High level function to manipulate export options on a mount point 293 * and the passed in netexport. 294 * Struct export_args *argp is the variable used to twiddle options, 295 * the structure is described in sys/mount.h 296 */ 297 int 298 vfs_export(struct mount *mp, struct export_args *argp) 299 { 300 struct netexport *nep; 301 int error; 302 303 if (argp->ex_numsecflavors < 0 304 || argp->ex_numsecflavors >= MAXSECFLAVORS) 305 return (EINVAL); 306 307 error = 0; 308 lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL); 309 nep = mp->mnt_export; 310 if (argp->ex_flags & MNT_DELEXPORT) { 311 if (nep == NULL) { 312 error = ENOENT; 313 goto out; 314 } 315 if (mp->mnt_flag & MNT_EXPUBLIC) { 316 vfs_setpublicfs(NULL, NULL, NULL); 317 MNT_ILOCK(mp); 318 mp->mnt_flag &= ~MNT_EXPUBLIC; 319 MNT_IUNLOCK(mp); 320 } 321 vfs_free_addrlist(nep); 322 mp->mnt_export = NULL; 323 free(nep, M_MOUNT); 324 nep = NULL; 325 MNT_ILOCK(mp); 326 mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED); 327 MNT_IUNLOCK(mp); 328 } 329 if (argp->ex_flags & MNT_EXPORTED) { 330 if (nep == NULL) { 331 nep = malloc(sizeof(struct netexport), M_MOUNT, M_WAITOK | M_ZERO); 332 mp->mnt_export = nep; 333 } 334 if (argp->ex_flags & MNT_EXPUBLIC) { 335 if ((error = vfs_setpublicfs(mp, nep, argp)) != 0) 336 goto out; 337 MNT_ILOCK(mp); 338 mp->mnt_flag |= MNT_EXPUBLIC; 339 MNT_IUNLOCK(mp); 340 } 341 if ((error = vfs_hang_addrlist(mp, nep, argp))) 342 goto out; 343 MNT_ILOCK(mp); 344 mp->mnt_flag |= MNT_EXPORTED; 345 MNT_IUNLOCK(mp); 346 } 347 348 out: 349 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL); 350 /* 351 * Once we have executed the vfs_export() command, we do 352 * not want to keep the "export" option around in the 353 * options list, since that will cause subsequent MNT_UPDATE 354 * calls to fail. The export information is saved in 355 * mp->mnt_export, so we can safely delete the "export" mount option 356 * here. 357 */ 358 vfs_deleteopt(mp->mnt_optnew, "export"); 359 vfs_deleteopt(mp->mnt_opt, "export"); 360 return (error); 361 } 362 363 /* 364 * Set the publicly exported filesystem (WebNFS). Currently, only 365 * one public filesystem is possible in the spec (RFC 2054 and 2055) 366 */ 367 int 368 vfs_setpublicfs(struct mount *mp, struct netexport *nep, 369 struct export_args *argp) 370 { 371 int error; 372 struct vnode *rvp; 373 char *cp; 374 375 /* 376 * mp == NULL -> invalidate the current info, the FS is 377 * no longer exported. May be called from either vfs_export 378 * or unmount, so check if it hasn't already been done. 379 */ 380 if (mp == NULL) { 381 if (nfs_pub.np_valid) { 382 nfs_pub.np_valid = 0; 383 if (nfs_pub.np_index != NULL) { 384 free(nfs_pub.np_index, M_TEMP); 385 nfs_pub.np_index = NULL; 386 } 387 } 388 return (0); 389 } 390 391 /* 392 * Only one allowed at a time. 393 */ 394 if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount) 395 return (EBUSY); 396 397 /* 398 * Get real filehandle for root of exported FS. 399 */ 400 bzero(&nfs_pub.np_handle, sizeof(nfs_pub.np_handle)); 401 nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid; 402 403 if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rvp))) 404 return (error); 405 406 if ((error = VOP_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid))) 407 return (error); 408 409 vput(rvp); 410 411 /* 412 * If an indexfile was specified, pull it in. 413 */ 414 if (argp->ex_indexfile != NULL) { 415 if (nfs_pub.np_index == NULL) 416 nfs_pub.np_index = malloc(MAXNAMLEN + 1, M_TEMP, 417 M_WAITOK); 418 error = copyinstr(argp->ex_indexfile, nfs_pub.np_index, 419 MAXNAMLEN, (size_t *)0); 420 if (!error) { 421 /* 422 * Check for illegal filenames. 423 */ 424 for (cp = nfs_pub.np_index; *cp; cp++) { 425 if (*cp == '/') { 426 error = EINVAL; 427 break; 428 } 429 } 430 } 431 if (error) { 432 free(nfs_pub.np_index, M_TEMP); 433 nfs_pub.np_index = NULL; 434 return (error); 435 } 436 } 437 438 nfs_pub.np_mount = mp; 439 nfs_pub.np_valid = 1; 440 return (0); 441 } 442 443 /* 444 * Used by the filesystems to determine if a given network address 445 * (passed in 'nam') is present in their exports list, returns a pointer 446 * to struct netcred so that the filesystem can examine it for 447 * access rights (read/write/etc). 448 */ 449 static struct netcred * 450 vfs_export_lookup(struct mount *mp, struct sockaddr *nam) 451 { 452 RADIX_NODE_HEAD_RLOCK_TRACKER; 453 struct netexport *nep; 454 struct netcred *np = NULL; 455 struct radix_node_head *rnh; 456 struct sockaddr *saddr; 457 458 nep = mp->mnt_export; 459 if (nep == NULL) 460 return (NULL); 461 if ((mp->mnt_flag & MNT_EXPORTED) == 0) 462 return (NULL); 463 464 /* 465 * Lookup in the export list 466 */ 467 if (nam != NULL) { 468 saddr = nam; 469 rnh = NULL; 470 switch (saddr->sa_family) { 471 case AF_INET: 472 rnh = nep->ne4; 473 break; 474 case AF_INET6: 475 rnh = nep->ne6; 476 break; 477 } 478 if (rnh != NULL) { 479 RADIX_NODE_HEAD_RLOCK(rnh); 480 np = (struct netcred *) (*rnh->rnh_matchaddr)(saddr, &rnh->rh); 481 RADIX_NODE_HEAD_RUNLOCK(rnh); 482 if (np != NULL && (np->netc_rnodes->rn_flags & RNF_ROOT) != 0) 483 return (NULL); 484 } 485 } 486 487 /* 488 * If no address match, use the default if it exists. 489 */ 490 if (np == NULL && (mp->mnt_flag & MNT_DEFEXPORTED) != 0) 491 return (&nep->ne_defexported); 492 493 return (np); 494 } 495 496 /* 497 * XXX: This comment comes from the deprecated ufs_check_export() 498 * XXX: and may not entirely apply, but lacking something better: 499 * This is the generic part of fhtovp called after the underlying 500 * filesystem has validated the file handle. 501 * 502 * Verify that a host should have access to a filesystem. 503 */ 504 505 int 506 vfs_stdcheckexp(struct mount *mp, struct sockaddr *nam, int *extflagsp, 507 struct ucred **credanonp, int *numsecflavors, int **secflavors) 508 { 509 struct netcred *np; 510 511 lockmgr(&mp->mnt_explock, LK_SHARED, NULL); 512 np = vfs_export_lookup(mp, nam); 513 if (np == NULL) { 514 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL); 515 *credanonp = NULL; 516 return (EACCES); 517 } 518 *extflagsp = np->netc_exflags; 519 if ((*credanonp = np->netc_anon) != NULL) 520 crhold(*credanonp); 521 if (numsecflavors) 522 *numsecflavors = np->netc_numsecflavors; 523 if (secflavors) 524 *secflavors = np->netc_secflavors; 525 lockmgr(&mp->mnt_explock, LK_RELEASE, NULL); 526 return (0); 527 } 528
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