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freebsd/sys/kern/vfs_export.c
Warner Losh 29363fb446 sys: Remove ancient SCCS tags.
Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by:		Netflix
2023-11-26 22:23:30 -07:00

697 lines
18 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* 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. 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.
*/
#include <sys/cdefs.h>
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dirent.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/rmlock.h>
#include <sys/refcount.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/vnode.h>
#include <netinet/in.h>
#include <net/radix.h>
#include <rpc/types.h>
#include <rpc/auth.h>
static MALLOC_DEFINE(M_NETADDR, "export_host", "Export host address structure");
#if defined(INET) || defined(INET6)
static struct radix_node_head *vfs_create_addrlist_af(
struct radix_node_head **prnh, int off);
#endif
static int vfs_free_netcred(struct radix_node *rn, void *w);
static void vfs_free_addrlist_af(struct radix_node_head **prnh);
static int vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
struct export_args *argp);
static struct netcred *vfs_export_lookup(struct mount *, struct sockaddr *);
/*
* Network address lookup element
*/
struct netcred {
struct radix_node netc_rnodes[2];
uint64_t netc_exflags;
struct ucred *netc_anon;
int netc_numsecflavors;
int netc_secflavors[MAXSECFLAVORS];
};
/*
* Network export information
*/
struct netexport {
struct netcred ne_defexported; /* Default export */
struct radix_node_head *ne4;
struct radix_node_head *ne6;
};
/*
* Build hash lists of net addresses and hang them off the mount point.
* Called by vfs_export() to set up the lists of export addresses.
*/
static int
vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
struct export_args *argp)
{
struct netcred *np;
struct radix_node_head *rnh;
int i;
struct radix_node *rn;
struct sockaddr *saddr, *smask = NULL;
#if defined(INET6) || defined(INET)
int off;
#endif
int error;
KASSERT(argp->ex_numsecflavors > 0,
("%s: numsecflavors <= 0", __func__));
KASSERT(argp->ex_numsecflavors < MAXSECFLAVORS,
("%s: numsecflavors >= MAXSECFLAVORS", __func__));
/*
* XXX: This routine converts from a uid plus gid list
* 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_addrlen == 0) {
if (mp->mnt_flag & MNT_DEFEXPORTED) {
vfs_mount_error(mp,
"MNT_DEFEXPORTED already set for mount %p", mp);
return (EPERM);
}
np = &nep->ne_defexported;
np->netc_exflags = argp->ex_flags;
np->netc_anon = crget();
np->netc_anon->cr_uid = argp->ex_uid;
crsetgroups(np->netc_anon, argp->ex_ngroups,
argp->ex_groups);
np->netc_anon->cr_prison = &prison0;
prison_hold(np->netc_anon->cr_prison);
np->netc_numsecflavors = argp->ex_numsecflavors;
bcopy(argp->ex_secflavors, np->netc_secflavors,
sizeof(np->netc_secflavors));
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_DEFEXPORTED;
MNT_IUNLOCK(mp);
return (0);
}
#if MSIZE <= 256
if (argp->ex_addrlen > MLEN) {
vfs_mount_error(mp, "ex_addrlen %d is greater than %d",
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_family == AF_UNSPEC || saddr->sa_family > AF_MAX) {
error = EINVAL;
vfs_mount_error(mp, "Invalid saddr->sa_family: %d");
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;
}
rnh = NULL;
switch (saddr->sa_family) {
#ifdef INET
case AF_INET:
if ((rnh = nep->ne4) == NULL) {
off = offsetof(struct sockaddr_in, sin_addr) << 3;
rnh = vfs_create_addrlist_af(&nep->ne4, off);
}
break;
#endif
#ifdef INET6
case AF_INET6:
if ((rnh = nep->ne6) == NULL) {
off = offsetof(struct sockaddr_in6, sin6_addr) << 3;
rnh = vfs_create_addrlist_af(&nep->ne6, off);
}
break;
#endif
}
if (rnh == NULL) {
error = ENOBUFS;
vfs_mount_error(mp, "%s %s %d",
"Unable to initialize radix node head ",
"for address family", saddr->sa_family);
goto out;
}
RADIX_NODE_HEAD_LOCK(rnh);
rn = (*rnh->rnh_addaddr)(saddr, smask, &rnh->rh, np->netc_rnodes);
RADIX_NODE_HEAD_UNLOCK(rnh);
if (rn == NULL || np != (struct netcred *)rn) { /* already exists */
error = EPERM;
vfs_mount_error(mp,
"netcred already exists for given addr/mask");
goto out;
}
np->netc_exflags = argp->ex_flags;
np->netc_anon = crget();
np->netc_anon->cr_uid = argp->ex_uid;
crsetgroups(np->netc_anon, argp->ex_ngroups,
argp->ex_groups);
np->netc_anon->cr_prison = &prison0;
prison_hold(np->netc_anon->cr_prison);
np->netc_numsecflavors = argp->ex_numsecflavors;
bcopy(argp->ex_secflavors, np->netc_secflavors,
sizeof(np->netc_secflavors));
return (0);
out:
free(np, M_NETADDR);
return (error);
}
/* Helper for vfs_free_addrlist. */
/* ARGSUSED */
static int
vfs_free_netcred(struct radix_node *rn, void *w)
{
struct radix_node_head *rnh = (struct radix_node_head *) w;
struct ucred *cred;
(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, &rnh->rh);
cred = ((struct netcred *)rn)->netc_anon;
if (cred != NULL)
crfree(cred);
free(rn, M_NETADDR);
return (0);
}
#if defined(INET) || defined(INET6)
static struct radix_node_head *
vfs_create_addrlist_af(struct radix_node_head **prnh, int off)
{
if (rn_inithead((void **)prnh, off) == 0)
return (NULL);
RADIX_NODE_HEAD_LOCK_INIT(*prnh);
return (*prnh);
}
#endif
static void
vfs_free_addrlist_af(struct radix_node_head **prnh)
{
struct radix_node_head *rnh;
rnh = *prnh;
RADIX_NODE_HEAD_LOCK(rnh);
(*rnh->rnh_walktree)(&rnh->rh, vfs_free_netcred, rnh);
RADIX_NODE_HEAD_UNLOCK(rnh);
RADIX_NODE_HEAD_DESTROY(rnh);
rn_detachhead((void **)prnh);
prnh = NULL;
}
/*
* Free the net address hash lists that are hanging off the mount points.
*/
void
vfs_free_addrlist(struct netexport *nep)
{
struct ucred *cred;
if (nep->ne4 != NULL)
vfs_free_addrlist_af(&nep->ne4);
if (nep->ne6 != NULL)
vfs_free_addrlist_af(&nep->ne6);
cred = nep->ne_defexported.netc_anon;
if (cred != NULL) {
crfree(cred);
nep->ne_defexported.netc_anon = NULL;
}
}
/*
* 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
* The do_exjail argument should be true if *mp is in the mountlist
* and false if not. It is not in the mountlist for the NFSv4 rootfs
* fake mount point just used for exports.
*/
int
vfs_export(struct mount *mp, struct export_args *argp, bool do_exjail)
{
struct netexport *nep;
struct ucred *cr;
struct prison *pr;
int error;
bool new_nep;
if ((argp->ex_flags & (MNT_DELEXPORT | MNT_EXPORTED)) == 0)
return (EINVAL);
if ((argp->ex_flags & MNT_EXPORTED) != 0 &&
(argp->ex_numsecflavors < 0
|| argp->ex_numsecflavors >= MAXSECFLAVORS))
return (EINVAL);
error = 0;
pr = curthread->td_ucred->cr_prison;
lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
nep = mp->mnt_export;
if (argp->ex_flags & MNT_DELEXPORT) {
if (nep == NULL) {
error = ENOENT;
goto out;
}
MNT_ILOCK(mp);
if (mp->mnt_exjail != NULL && mp->mnt_exjail->cr_prison != pr &&
pr == &prison0) {
MNT_IUNLOCK(mp);
/* EXDEV will not get logged by mountd(8). */
error = EXDEV;
goto out;
} else if (mp->mnt_exjail != NULL &&
mp->mnt_exjail->cr_prison != pr) {
MNT_IUNLOCK(mp);
/* EPERM will get logged by mountd(8). */
error = EPERM;
goto out;
}
MNT_IUNLOCK(mp);
if (mp->mnt_flag & MNT_EXPUBLIC) {
vfs_setpublicfs(NULL, NULL, NULL);
MNT_ILOCK(mp);
mp->mnt_flag &= ~MNT_EXPUBLIC;
MNT_IUNLOCK(mp);
}
vfs_free_addrlist(nep);
mp->mnt_export = NULL;
free(nep, M_MOUNT);
nep = NULL;
MNT_ILOCK(mp);
cr = mp->mnt_exjail;
mp->mnt_exjail = NULL;
mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
MNT_IUNLOCK(mp);
if (cr != NULL) {
atomic_subtract_int(&pr->pr_exportcnt, 1);
crfree(cr);
}
}
if (argp->ex_flags & MNT_EXPORTED) {
new_nep = false;
MNT_ILOCK(mp);
if (mp->mnt_exjail == NULL) {
MNT_IUNLOCK(mp);
if (do_exjail && nep != NULL) {
vfs_free_addrlist(nep);
memset(nep, 0, sizeof(*nep));
new_nep = true;
}
} else if (mp->mnt_exjail->cr_prison != pr) {
MNT_IUNLOCK(mp);
error = EPERM;
goto out;
} else
MNT_IUNLOCK(mp);
if (nep == NULL) {
nep = malloc(sizeof(struct netexport), M_MOUNT,
M_WAITOK | M_ZERO);
mp->mnt_export = nep;
new_nep = true;
}
if (argp->ex_flags & MNT_EXPUBLIC) {
if ((error = vfs_setpublicfs(mp, nep, argp)) != 0) {
if (new_nep) {
mp->mnt_export = NULL;
free(nep, M_MOUNT);
}
goto out;
}
new_nep = false;
MNT_ILOCK(mp);
if (do_exjail && mp->mnt_exjail == NULL) {
mp->mnt_exjail = crhold(curthread->td_ucred);
atomic_add_int(&pr->pr_exportcnt, 1);
}
mp->mnt_flag |= MNT_EXPUBLIC;
MNT_IUNLOCK(mp);
}
if (argp->ex_numsecflavors == 0) {
argp->ex_numsecflavors = 1;
argp->ex_secflavors[0] = AUTH_SYS;
}
if ((error = vfs_hang_addrlist(mp, nep, argp))) {
if (new_nep) {
mp->mnt_export = NULL;
free(nep, M_MOUNT);
}
goto out;
}
MNT_ILOCK(mp);
if (do_exjail && mp->mnt_exjail == NULL) {
mp->mnt_exjail = crhold(curthread->td_ucred);
atomic_add_int(&pr->pr_exportcnt, 1);
}
mp->mnt_flag |= MNT_EXPORTED;
MNT_IUNLOCK(mp);
}
out:
lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
/*
* Once we have executed the vfs_export() command, we do
* not want to keep the "export" option around in the
* options list, since that will cause subsequent MNT_UPDATE
* calls to fail. The export information is saved in
* mp->mnt_export, so we can safely delete the "export" mount option
* here.
*/
vfs_deleteopt(mp->mnt_optnew, "export");
vfs_deleteopt(mp->mnt_opt, "export");
return (error);
}
/*
* Get rid of credential references for this prison.
*/
void
vfs_exjail_delete(struct prison *pr)
{
struct mount *mp;
struct ucred *cr;
int error, i;
/*
* Since this function is called from prison_cleanup() after
* all processes in the prison have exited, the value of
* pr_exportcnt can no longer increase. It is possible for
* a dismount of a file system exported within this prison
* to be in progress. In this case, the file system is no
* longer in the mountlist and the mnt_exjail will be free'd
* by vfs_mount_destroy() at some time. As such, pr_exportcnt
* and, therefore "i", is the upper bound on the number of
* mnt_exjail entries to be found by this function.
*/
i = atomic_load_int(&pr->pr_exportcnt);
KASSERT(i >= 0, ("vfs_exjail_delete: pr_exportcnt negative"));
if (i == 0)
return;
mtx_lock(&mountlist_mtx);
tryagain:
TAILQ_FOREACH(mp, &mountlist, mnt_list) {
MNT_ILOCK(mp);
if (mp->mnt_exjail != NULL &&
mp->mnt_exjail->cr_prison == pr) {
MNT_IUNLOCK(mp);
error = vfs_busy(mp, MBF_MNTLSTLOCK | MBF_NOWAIT);
if (error != 0) {
/*
* If the vfs_busy() fails, we still want to
* get rid of mnt_exjail for two reasons:
* - a credential reference will result in
* a prison not being removed
* - setting mnt_exjail NULL indicates that
* the exports are no longer valid
* The now invalid exports will be deleted
* when the file system is dismounted or
* the file system is re-exported by mountd.
*/
cr = NULL;
MNT_ILOCK(mp);
if (mp->mnt_exjail != NULL &&
mp->mnt_exjail->cr_prison == pr) {
cr = mp->mnt_exjail;
mp->mnt_exjail = NULL;
}
MNT_IUNLOCK(mp);
if (cr != NULL) {
crfree(cr);
i--;
}
if (i == 0)
break;
continue;
}
cr = NULL;
lockmgr(&mp->mnt_explock, LK_EXCLUSIVE, NULL);
MNT_ILOCK(mp);
if (mp->mnt_exjail != NULL &&
mp->mnt_exjail->cr_prison == pr) {
cr = mp->mnt_exjail;
mp->mnt_exjail = NULL;
mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
MNT_IUNLOCK(mp);
vfs_free_addrlist(mp->mnt_export);
free(mp->mnt_export, M_MOUNT);
mp->mnt_export = NULL;
} else
MNT_IUNLOCK(mp);
lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
if (cr != NULL) {
crfree(cr);
i--;
}
mtx_lock(&mountlist_mtx);
vfs_unbusy(mp);
if (i == 0)
break;
goto tryagain;
}
MNT_IUNLOCK(mp);
}
mtx_unlock(&mountlist_mtx);
}
/*
* Set the publicly exported filesystem (WebNFS). Currently, only
* one public filesystem is possible in the spec (RFC 2054 and 2055)
*/
int
vfs_setpublicfs(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, LK_EXCLUSIVE, &rvp)))
return (error);
if ((error = VOP_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) {
if (nfs_pub.np_index == NULL)
nfs_pub.np_index = malloc(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);
nfs_pub.np_index = NULL;
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 their exports list, returns a pointer
* to struct netcred so that the filesystem can examine it for
* access rights (read/write/etc).
*/
static struct netcred *
vfs_export_lookup(struct mount *mp, struct sockaddr *nam)
{
RADIX_NODE_HEAD_RLOCK_TRACKER;
struct netexport *nep;
struct netcred *np = NULL;
struct radix_node_head *rnh;
struct sockaddr *saddr;
nep = mp->mnt_export;
if (nep == NULL)
return (NULL);
if ((mp->mnt_flag & MNT_EXPORTED) == 0)
return (NULL);
/*
* Lookup in the export list
*/
if (nam != NULL) {
saddr = nam;
rnh = NULL;
switch (saddr->sa_family) {
case AF_INET:
rnh = nep->ne4;
break;
case AF_INET6:
rnh = nep->ne6;
break;
}
if (rnh != NULL) {
RADIX_NODE_HEAD_RLOCK(rnh);
np = (struct netcred *) (*rnh->rnh_matchaddr)(saddr, &rnh->rh);
RADIX_NODE_HEAD_RUNLOCK(rnh);
if (np != NULL && (np->netc_rnodes->rn_flags & RNF_ROOT) != 0)
return (NULL);
}
}
/*
* If no address match, use the default if it exists.
*/
if (np == NULL && (mp->mnt_flag & MNT_DEFEXPORTED) != 0)
return (&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(struct mount *mp, struct sockaddr *nam, uint64_t *extflagsp,
struct ucred **credanonp, int *numsecflavors, int *secflavors)
{
struct netcred *np;
lockmgr(&mp->mnt_explock, LK_SHARED, NULL);
np = vfs_export_lookup(mp, nam);
if (np == NULL) {
lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
*credanonp = NULL;
return (EACCES);
}
*extflagsp = np->netc_exflags;
if ((*credanonp = np->netc_anon) != NULL)
crhold(*credanonp);
if (numsecflavors) {
*numsecflavors = np->netc_numsecflavors;
KASSERT(*numsecflavors > 0,
("%s: numsecflavors <= 0", __func__));
KASSERT(*numsecflavors < MAXSECFLAVORS,
("%s: numsecflavors >= MAXSECFLAVORS", __func__));
}
if (secflavors && np->netc_numsecflavors > 0)
memcpy(secflavors, np->netc_secflavors, np->netc_numsecflavors *
sizeof(int));
lockmgr(&mp->mnt_explock, LK_RELEASE, NULL);
return (0);
}