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/*
* Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/param.h>
#include <sys/priv.h>
#include <sys/vnode.h>
#include <sys/mntent.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/jail.h>
#include <sys/policy.h>
#include <sys/zfs_vfsops.h>
#include <sys/zfs_znode.h>
int
secpolicy_nfs(cred_t *cr)
{
return (spl_priv_check_cred(cr, PRIV_NFS_DAEMON));
}
int
secpolicy_zfs(cred_t *cr)
{
return (spl_priv_check_cred(cr, PRIV_VFS_MOUNT));
}
int
secpolicy_zfs_proc(cred_t *cr, proc_t *proc)
{
return (spl_priv_check_cred(cr, PRIV_VFS_MOUNT));
}
int
secpolicy_sys_config(cred_t *cr, int checkonly __unused)
{
return (spl_priv_check_cred(cr, PRIV_ZFS_POOL_CONFIG));
}
int
secpolicy_zinject(cred_t *cr)
{
return (spl_priv_check_cred(cr, PRIV_ZFS_INJECT));
}
int
secpolicy_fs_unmount(cred_t *cr, struct mount *vfsp __unused)
{
return (spl_priv_check_cred(cr, PRIV_VFS_UNMOUNT));
}
int
secpolicy_fs_owner(struct mount *mp, cred_t *cr)
{
if (zfs_super_owner) {
if (cr->cr_uid == mp->mnt_cred->cr_uid &&
cr->cr_prison == mp->mnt_cred->cr_prison) {
return (0);
}
}
return (EPERM);
}
/*
* This check is done in kern_link(), so we could just return 0 here.
*/
extern int hardlink_check_uid;
int
secpolicy_basic_link(vnode_t *vp, cred_t *cr)
{
if (!hardlink_check_uid)
return (0);
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
return (spl_priv_check_cred(cr, PRIV_VFS_LINK));
}
int
secpolicy_vnode_stky_modify(cred_t *cr)
{
return (EPERM);
}
int
secpolicy_vnode_remove(vnode_t *vp, cred_t *cr)
{
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
return (spl_priv_check_cred(cr, PRIV_VFS_ADMIN));
}
int
secpolicy_vnode_access(cred_t *cr, vnode_t *vp, uid_t owner, accmode_t accmode)
{
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
if ((accmode & VREAD) && spl_priv_check_cred(cr, PRIV_VFS_READ) != 0)
return (EACCES);
if ((accmode & VWRITE) &&
spl_priv_check_cred(cr, PRIV_VFS_WRITE) != 0) {
return (EACCES);
}
if (accmode & VEXEC) {
if (vp->v_type == VDIR) {
if (spl_priv_check_cred(cr, PRIV_VFS_LOOKUP) != 0)
return (EACCES);
} else {
if (spl_priv_check_cred(cr, PRIV_VFS_EXEC) != 0)
return (EACCES);
}
}
return (0);
}
/*
* Like secpolicy_vnode_access() but we get the actual wanted mode and the
* current mode of the file, not the missing bits.
*/
int
secpolicy_vnode_access2(cred_t *cr, vnode_t *vp, uid_t owner,
accmode_t curmode, accmode_t wantmode)
{
accmode_t mode;
mode = ~curmode & wantmode;
if (mode == 0)
return (0);
return (secpolicy_vnode_access(cr, vp, owner, mode));
}
int
secpolicy_vnode_any_access(cred_t *cr, vnode_t *vp, uid_t owner)
{
static int privs[] = {
PRIV_VFS_ADMIN,
PRIV_VFS_READ,
PRIV_VFS_WRITE,
PRIV_VFS_EXEC,
PRIV_VFS_LOOKUP
};
int i;
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
/* Same as secpolicy_vnode_setdac */
if (owner == cr->cr_uid)
return (0);
for (i = 0; i < sizeof (privs)/sizeof (int); i++) {
int priv;
switch (priv = privs[i]) {
case PRIV_VFS_EXEC:
if (vp->v_type == VDIR)
continue;
break;
case PRIV_VFS_LOOKUP:
if (vp->v_type != VDIR)
continue;
break;
}
if (spl_priv_check_cred(cr, priv) == 0)
return (0);
}
return (EPERM);
}
int
secpolicy_vnode_setdac(vnode_t *vp, cred_t *cr, uid_t owner)
{
if (owner == cr->cr_uid)
return (0);
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
return (spl_priv_check_cred(cr, PRIV_VFS_ADMIN));
}
int
secpolicy_vnode_setattr(cred_t *cr, vnode_t *vp, struct vattr *vap,
const struct vattr *ovap, int flags,
int unlocked_access(void *, int, cred_t *), void *node)
{
int mask = vap->va_mask;
int error;
if (mask & AT_SIZE) {
if (vp->v_type == VDIR)
return (EISDIR);
error = unlocked_access(node, VWRITE, cr);
if (error)
return (error);
}
if (mask & AT_MODE) {
/*
* If not the owner of the file then check privilege
* for two things: the privilege to set the mode at all
* and, if we're setting setuid, we also need permissions
* to add the set-uid bit, if we're not the owner.
* In the specific case of creating a set-uid root
* file, we need even more permissions.
*/
error = secpolicy_vnode_setdac(vp, cr, ovap->va_uid);
if (error)
return (error);
error = secpolicy_setid_setsticky_clear(vp, vap, ovap, cr);
if (error)
return (error);
} else {
vap->va_mode = ovap->va_mode;
}
if (mask & (AT_UID | AT_GID)) {
error = secpolicy_vnode_setdac(vp, cr, ovap->va_uid);
if (error)
return (error);
/*
* To change the owner of a file, or change the group of
* a file to a group of which we are not a member, the
* caller must have privilege.
*/
if (((mask & AT_UID) && vap->va_uid != ovap->va_uid) ||
((mask & AT_GID) && vap->va_gid != ovap->va_gid &&
!groupmember(vap->va_gid, cr))) {
if (secpolicy_fs_owner(vp->v_mount, cr) != 0) {
error = spl_priv_check_cred(cr, PRIV_VFS_CHOWN);
if (error)
return (error);
}
}
if (((mask & AT_UID) && vap->va_uid != ovap->va_uid) ||
((mask & AT_GID) && vap->va_gid != ovap->va_gid)) {
secpolicy_setid_clear(vap, vp, cr);
}
}
if (mask & (AT_ATIME | AT_MTIME)) {
/*
* From utimes(2):
* If times is NULL, ... The caller must be the owner of
* the file, have permission to write the file, or be the
* super-user.
* If times is non-NULL, ... The caller must be the owner of
* the file or be the super-user.
*/
error = secpolicy_vnode_setdac(vp, cr, ovap->va_uid);
if (error && (vap->va_vaflags & VA_UTIMES_NULL))
error = unlocked_access(node, VWRITE, cr);
if (error)
return (error);
}
return (0);
}
int
secpolicy_vnode_create_gid(cred_t *cr)
{
return (EPERM);
}
int
secpolicy_vnode_setids_setgids(vnode_t *vp, cred_t *cr, gid_t gid)
{
if (groupmember(gid, cr))
return (0);
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
return (spl_priv_check_cred(cr, PRIV_VFS_SETGID));
}
int
secpolicy_vnode_setid_retain(znode_t *zp, cred_t *cr,
boolean_t issuidroot __unused)
{
if (secpolicy_fs_owner(ZTOV(zp)->v_mount, cr) == 0)
return (0);
return (spl_priv_check_cred(cr, PRIV_VFS_RETAINSUGID));
}
void
secpolicy_setid_clear(struct vattr *vap, vnode_t *vp, cred_t *cr)
{
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return;
if ((vap->va_mode & (S_ISUID | S_ISGID)) != 0) {
if (spl_priv_check_cred(cr, PRIV_VFS_RETAINSUGID)) {
vap->va_mask |= AT_MODE;
vap->va_mode &= ~(S_ISUID|S_ISGID);
}
}
}
int
secpolicy_setid_setsticky_clear(vnode_t *vp, struct vattr *vap,
const struct vattr *ovap, cred_t *cr)
{
int error;
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
/*
* Privileged processes may set the sticky bit on non-directories,
* as well as set the setgid bit on a file with a group that the process
* is not a member of. Both of these are allowed in jail(8).
*/
if (vp->v_type != VDIR && (vap->va_mode & S_ISTXT)) {
if (spl_priv_check_cred(cr, PRIV_VFS_STICKYFILE))
return (EFTYPE);
}
/*
* Check for privilege if attempting to set the
* group-id bit.
*/
if ((vap->va_mode & S_ISGID) != 0) {
error = secpolicy_vnode_setids_setgids(vp, cr, ovap->va_gid);
if (error)
return (error);
}
/*
* Deny setting setuid if we are not the file owner.
*/
if ((vap->va_mode & S_ISUID) && ovap->va_uid != cr->cr_uid) {
error = spl_priv_check_cred(cr, PRIV_VFS_ADMIN);
if (error)
return (error);
}
return (0);
}
int
secpolicy_fs_mount(cred_t *cr, vnode_t *mvp, struct mount *vfsp)
{
return (spl_priv_check_cred(cr, PRIV_VFS_MOUNT));
}
int
secpolicy_vnode_owner(vnode_t *vp, cred_t *cr, uid_t owner)
{
if (owner == cr->cr_uid)
return (0);
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
/* XXX: vfs_suser()? */
return (spl_priv_check_cred(cr, PRIV_VFS_MOUNT_OWNER));
}
int
secpolicy_vnode_chown(vnode_t *vp, cred_t *cr, uid_t owner)
{
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
return (spl_priv_check_cred(cr, PRIV_VFS_CHOWN));
}
void
secpolicy_fs_mount_clearopts(cred_t *cr, struct mount *vfsp)
{
if (spl_priv_check_cred(cr, PRIV_VFS_MOUNT_NONUSER) != 0) {
MNT_ILOCK(vfsp);
vfsp->vfs_flag |= VFS_NOSETUID | MNT_USER;
vfs_clearmntopt(vfsp, MNTOPT_SETUID);
vfs_setmntopt(vfsp, MNTOPT_NOSETUID, NULL, 0);
MNT_IUNLOCK(vfsp);
}
}
/*
* Check privileges for setting xvattr attributes
*/
int
secpolicy_xvattr(vnode_t *vp, xvattr_t *xvap, uid_t owner, cred_t *cr,
vtype_t vtype)
{
if (secpolicy_fs_owner(vp->v_mount, cr) == 0)
return (0);
return (spl_priv_check_cred(cr, PRIV_VFS_SYSFLAGS));
}
int
secpolicy_smb(cred_t *cr)
{
return (spl_priv_check_cred(cr, PRIV_NETSMB));
}