FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_export.c

     /*
      * Copyright (c) 1989, 1993
      *      The Regents of the University of California.  All rights reserved.
      * (c) UNIX System Laboratories, Inc.
      * All or some portions of this file are derived from material licensed
      * to the University of California by American Telephone and Telegraph
      * Co. or Unix System Laboratories, Inc. and are reproduced herein with
      * the permission of UNIX System Laboratories, Inc.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)vfs_subr.c  8.31 (Berkeley) 5/26/95
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/5.2/sys/kern/vfs_export.c 118045 2003-07-26 07:23:24Z scottl $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/socket.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <sys/mount.h>
    #include <net/radix.h>
    #include <sys/domain.h>
    #include <sys/dirent.h>
    #include <sys/vnode.h>
    
    static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
    
    static void     vfs_free_addrlist(struct netexport *nep);
    static int      vfs_free_netcred(struct radix_node *rn, void *w);
    static int      vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
                        struct export_args *argp);
    
    /*
     * Network address lookup element
     */
    struct netcred {
            struct  radix_node netc_rnodes[2];
            int     netc_exflags;
            struct  ucred netc_anon;
    };
    
    /*
     * Network export information
     */
    struct netexport {
            struct  netcred ne_defexported;               /* Default export */
            struct  radix_node_head *ne_rtable[AF_MAX+1]; /* Individual exports */
    };
    
    /*
     * Build hash lists of net addresses and hang them off the mount point.
     * Called by ufs_mount() to set up the lists of export addresses.
     */
    static int
    vfs_hang_addrlist(mp, nep, argp)
            struct mount *mp;
            struct netexport *nep;
            struct export_args *argp;
    {
            register struct netcred *np;
            register struct radix_node_head *rnh;
            register int i;
            struct radix_node *rn;
            struct sockaddr *saddr, *smask = 0;
            struct domain *dom;
            int error;
    
            /*
             * XXX: This routine converts from a `struct xucred'
            * (argp->ex_anon) to a `struct ucred' (np->netc_anon).  This
            * operation is questionable; for example, what should be done
            * with fields like cr_uidinfo and cr_prison?  Currently, this
            * routine does not touch them (leaves them as NULL).
            */
           if (argp->ex_anon.cr_version != XUCRED_VERSION)
                   return (EINVAL);
   
           if (argp->ex_addrlen == 0) {
                   if (mp->mnt_flag & MNT_DEFEXPORTED)
                           return (EPERM);
                   np = &nep->ne_defexported;
                   np->netc_exflags = argp->ex_flags;
                   bzero(&np->netc_anon, sizeof(np->netc_anon));
                   np->netc_anon.cr_uid = argp->ex_anon.cr_uid;
                   np->netc_anon.cr_ngroups = argp->ex_anon.cr_ngroups;
                   bcopy(argp->ex_anon.cr_groups, np->netc_anon.cr_groups,
                       sizeof(np->netc_anon.cr_groups));
                   np->netc_anon.cr_ref = 1;
                   mp->mnt_flag |= MNT_DEFEXPORTED;
                   return (0);
           }
   
   #if MSIZE <= 256
           if (argp->ex_addrlen > MLEN)
                   return (EINVAL);
   #endif
   
           i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
           np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
           saddr = (struct sockaddr *) (np + 1);
           if ((error = copyin(argp->ex_addr, saddr, argp->ex_addrlen)))
                   goto out;
           if (saddr->sa_len > argp->ex_addrlen)
                   saddr->sa_len = argp->ex_addrlen;
           if (argp->ex_masklen) {
                   smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
                   error = copyin(argp->ex_mask, smask, argp->ex_masklen);
                   if (error)
                           goto out;
                   if (smask->sa_len > argp->ex_masklen)
                           smask->sa_len = argp->ex_masklen;
           }
           i = saddr->sa_family;
           if ((rnh = nep->ne_rtable[i]) == NULL) {
                   /*
                    * Seems silly to initialize every AF when most are not used,
                    * do so on demand here
                    */
                   for (dom = domains; dom; dom = dom->dom_next)
                           if (dom->dom_family == i && dom->dom_rtattach) {
                                   dom->dom_rtattach((void **) &nep->ne_rtable[i],
                                       dom->dom_rtoffset);
                                   break;
                           }
                   if ((rnh = nep->ne_rtable[i]) == NULL) {
                           error = ENOBUFS;
                           goto out;
                   }
           }
           RADIX_NODE_HEAD_LOCK(rnh);
           rn = (*rnh->rnh_addaddr)(saddr, smask, rnh, np->netc_rnodes);
           RADIX_NODE_HEAD_UNLOCK(rnh);
           if (rn == NULL || np != (struct netcred *)rn) { /* already exists */
                   error = EPERM;
                   goto out;
           }
           np->netc_exflags = argp->ex_flags;
           bzero(&np->netc_anon, sizeof(np->netc_anon));
           np->netc_anon.cr_uid = argp->ex_anon.cr_uid;
           np->netc_anon.cr_ngroups = argp->ex_anon.cr_ngroups;
           bcopy(argp->ex_anon.cr_groups, np->netc_anon.cr_groups,
               sizeof(np->netc_anon.cr_groups));
           np->netc_anon.cr_ref = 1;
           return (0);
   out:
           free(np, M_NETADDR);
           return (error);
   }
   
   /* Helper for vfs_free_addrlist. */
   /* ARGSUSED */
   static int
   vfs_free_netcred(rn, w)
           struct radix_node *rn;
           void *w;
   {
           register struct radix_node_head *rnh = (struct radix_node_head *) w;
   
           (*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
           free(rn, M_NETADDR);
           return (0);
   }
   
   /*
    * Free the net address hash lists that are hanging off the mount points.
    */
   static void
   vfs_free_addrlist(nep)
           struct netexport *nep;
   {
           register int i;
           register struct radix_node_head *rnh;
   
           for (i = 0; i <= AF_MAX; i++)
                   if ((rnh = nep->ne_rtable[i])) {
                           RADIX_NODE_HEAD_LOCK(rnh);
                           (*rnh->rnh_walktree) (rnh, vfs_free_netcred, rnh);
                           RADIX_NODE_HEAD_DESTROY(rnh);
                           free(rnh, M_RTABLE);
                           nep->ne_rtable[i] = NULL;       /* not SMP safe XXX */
                   }
   }
   
   /*
    * High level function to manipulate export options on a mount point
    * and the passed in netexport.
    * Struct export_args *argp is the variable used to twiddle options,
    * the structure is described in sys/mount.h
    */
   int
   vfs_export(mp, argp)
           struct mount *mp;
           struct export_args *argp;
   {
           struct netexport *nep;
           int error;
   
           nep = mp->mnt_export;
           if (argp->ex_flags & MNT_DELEXPORT) {
                   if (nep == NULL)
                           return (ENOENT);
                   if (mp->mnt_flag & MNT_EXPUBLIC) {
                           vfs_setpublicfs(NULL, NULL, NULL);
                           mp->mnt_flag &= ~MNT_EXPUBLIC;
                   }
                   vfs_free_addrlist(nep);
                   mp->mnt_export = NULL;
                   free(nep, M_MOUNT);
                   mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
           }
           if (argp->ex_flags & MNT_EXPORTED) {
                   if (nep == NULL) {
                           nep = malloc(sizeof(struct netexport), M_MOUNT, M_WAITOK | M_ZERO);
                           mp->mnt_export = nep;
                   }
                   if (argp->ex_flags & MNT_EXPUBLIC) {
                           if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
                                   return (error);
                           mp->mnt_flag |= MNT_EXPUBLIC;
                   }
                   if ((error = vfs_hang_addrlist(mp, nep, argp)))
                           return (error);
                   mp->mnt_flag |= MNT_EXPORTED;
           }
           return (0);
   }
   
   /*
    * Set the publicly exported filesystem (WebNFS). Currently, only
    * one public filesystem is possible in the spec (RFC 2054 and 2055)
    */
   int
   vfs_setpublicfs(mp, nep, argp)
           struct mount *mp;
           struct netexport *nep;
           struct export_args *argp;
   {
           int error;
           struct vnode *rvp;
           char *cp;
   
           /*
            * mp == NULL -> invalidate the current info, the FS is
            * no longer exported. May be called from either vfs_export
            * or unmount, so check if it hasn't already been done.
            */
           if (mp == NULL) {
                   if (nfs_pub.np_valid) {
                           nfs_pub.np_valid = 0;
                           if (nfs_pub.np_index != NULL) {
                                   FREE(nfs_pub.np_index, M_TEMP);
                                   nfs_pub.np_index = NULL;
                           }
                   }
                   return (0);
           }
   
           /*
            * Only one allowed at a time.
            */
           if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
                   return (EBUSY);
   
           /*
            * Get real filehandle for root of exported FS.
            */
           bzero(&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
           nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
   
           if ((error = VFS_ROOT(mp, &rvp)))
                   return (error);
   
           if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
                   return (error);
   
           vput(rvp);
   
           /*
            * If an indexfile was specified, pull it in.
            */
           if (argp->ex_indexfile != NULL) {
                   MALLOC(nfs_pub.np_index, char *, MAXNAMLEN + 1, M_TEMP,
                       M_WAITOK);
                   error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
                       MAXNAMLEN, (size_t *)0);
                   if (!error) {
                           /*
                            * Check for illegal filenames.
                            */
                           for (cp = nfs_pub.np_index; *cp; cp++) {
                                   if (*cp == '/') {
                                           error = EINVAL;
                                           break;
                                   }
                           }
                   }
                   if (error) {
                           FREE(nfs_pub.np_index, M_TEMP);
                           return (error);
                   }
           }
   
           nfs_pub.np_mount = mp;
           nfs_pub.np_valid = 1;
           return (0);
   }
   
   /*
    * Used by the filesystems to determine if a given network address
    * (passed in 'nam') is present in thier exports list, returns a pointer
    * to struct netcred so that the filesystem can examine it for
    * access rights (read/write/etc).
    */
   struct netcred *
   vfs_export_lookup(mp, nam)
           register struct mount *mp;
           struct sockaddr *nam;
   {
           struct netexport *nep;
           register struct netcred *np;
           register struct radix_node_head *rnh;
           struct sockaddr *saddr;
   
           nep = mp->mnt_export;
           if (nep == NULL)
                   return (NULL);
           np = NULL;
           if (mp->mnt_flag & MNT_EXPORTED) {
                   /*
                    * Lookup in the export list first.
                    */
                   if (nam != NULL) {
                           saddr = nam;
                           rnh = nep->ne_rtable[saddr->sa_family];
                           if (rnh != NULL) {
                                   RADIX_NODE_HEAD_LOCK(rnh);
                                   np = (struct netcred *)
                                       (*rnh->rnh_matchaddr)(saddr, rnh);
                                   RADIX_NODE_HEAD_UNLOCK(rnh);
                                   if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
                                           np = NULL;
                           }
                   }
                   /*
                    * If no address match, use the default if it exists.
                    */
                   if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
                           np = &nep->ne_defexported;
           }
           return (np);
   }
   
   /*
    * XXX: This comment comes from the deprecated ufs_check_export()
    * XXX: and may not entirely apply, but lacking something better:
    * This is the generic part of fhtovp called after the underlying
    * filesystem has validated the file handle.
    *
    * Verify that a host should have access to a filesystem.
    */
   
   int 
   vfs_stdcheckexp(mp, nam, extflagsp, credanonp)
           struct mount *mp;
           struct sockaddr *nam;
           int *extflagsp;
           struct ucred **credanonp;
   {
           struct netcred *np;
   
           np = vfs_export_lookup(mp, nam);
           if (np == NULL)
                   return (EACCES);
           *extflagsp = np->netc_exflags;
           *credanonp = &np->netc_anon;
           return (0);
   }
   

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