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

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