/*-
* Copyright (c) 2001 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by NAI Labs, the
* Security Research Division of Network Associates, Inc. under
* DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
* CHATS research program.
*
* 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 the above entities nor the names of any
* contributors of those entities may be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $Id$
*/
/*
* Copyright (c) 1988 University of Utah.
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* 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.
*
* from: Utah $Hdr: vm_mmap.c 1.6 91/10/21$
*
* @(#)vm_mmap.c 8.4 (Berkeley) 1/12/94
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysproto.h>
#include <sys/filedesc.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/conf.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include "kernel_interface.h"
#include "kernel_mediate.h"
#include "kernel_monitor.h"
#include "kernel_util.h"
#include "lomacfs.h"
extern int max_proc_mmap;
int lomac_mmap(struct proc *, struct mmap_args *);
/*
* Memory Map (mmap) system call. Note that the file offset
* and address are allowed to be NOT page aligned, though if
* the MAP_FIXED flag it set, both must have the same remainder
* modulo the PAGE_SIZE (POSIX 1003.1b). If the address is not
* page-aligned, the actual mapping starts at trunc_page(addr)
* and the return value is adjusted up by the page offset.
*
* Generally speaking, only character devices which are themselves
* memory-based, such as a video framebuffer, can be mmap'd. Otherwise
* there would be no cache coherency between a descriptor and a VM mapping
* both to the same character device.
*
* Block devices can be mmap'd no matter what they represent. Cache coherency
* is maintained as long as you do not write directly to the underlying
* character device.
*/
#ifndef _SYS_SYSPROTO_H_
struct mmap_args {
void *addr;
size_t len;
int prot;
int flags;
int fd;
long pad;
off_t pos;
};
#endif
int
mmap(td, uap)
struct thread *td;
struct mmap_args *uap;
{
struct proc *p = td->td_proc;
struct filedesc *fdp = p->p_fd;
struct file *fp = NULL;
struct vnode *vp, *origvp;
vm_offset_t addr;
vm_size_t size, pageoff;
vm_prot_t prot, maxprot;
void *handle;
int flags, error;
int disablexworkaround;
off_t pos;
struct vmspace *vms = p->p_vmspace;
vm_object_t obj;
lomac_object_t lobj;
addr = (vm_offset_t) uap->addr;
size = uap->len;
prot = uap->prot & VM_PROT_ALL;
flags = uap->flags;
pos = uap->pos;
origvp = NULL;
/* make sure mapping fits into numeric range etc */
if ((ssize_t) uap->len < 0 ||
((flags & MAP_ANON) && uap->fd != -1))
return (EINVAL);
if (flags & MAP_STACK) {
if ((uap->fd != -1) ||
((prot & (PROT_READ | PROT_WRITE)) != (PROT_READ | PROT_WRITE)))
return (EINVAL);
flags |= MAP_ANON;
pos = 0;
}
/*
* Align the file position to a page boundary,
* and save its page offset component.
*/
pageoff = (pos & PAGE_MASK);
pos -= pageoff;
/* Adjust size for rounding (on both ends). */
size += pageoff; /* low end... */
size = (vm_size_t) round_page(size); /* hi end */
/*
* Check for illegal addresses. Watch out for address wrap... Note
* that VM_*_ADDRESS are not constants due to casts (argh).
*/
if (flags & MAP_FIXED) {
/*
* The specified address must have the same remainder
* as the file offset taken modulo PAGE_SIZE, so it
* should be aligned after adjustment by pageoff.
*/
addr -= pageoff;
if (addr & PAGE_MASK)
return (EINVAL);
/* Address range must be all in user VM space. */
if (VM_MAXUSER_ADDRESS > 0 && addr + size > VM_MAXUSER_ADDRESS)
return (EINVAL);
#ifndef __i386__
if (VM_MIN_ADDRESS > 0 && addr < VM_MIN_ADDRESS)
return (EINVAL);
#endif
if (addr + size < addr)
return (EINVAL);
}
/*
* XXX for non-fixed mappings where no hint is provided or
* the hint would fall in the potential heap space,
* place it after the end of the largest possible heap.
*
* There should really be a pmap call to determine a reasonable
* location.
*/
else if (addr == 0 ||
(addr >= round_page((vm_offset_t)vms->vm_taddr) &&
addr < round_page((vm_offset_t)vms->vm_daddr + MAXDSIZ)))
addr = round_page((vm_offset_t)vms->vm_daddr + MAXDSIZ);
mtx_lock(&Giant); /* syscall marked mp-safe but isn't */
if (flags & MAP_ANON) {
/*
* Mapping blank space is trivial.
*/
handle = NULL;
maxprot = VM_PROT_ALL;
pos = 0;
} else {
/*
* Mapping file, get fp for validation. Obtain vnode and make
* sure it is of appropriate type.
*/
if (((unsigned) uap->fd) >= fdp->fd_nfiles ||
(fp = fdp->fd_ofiles[uap->fd]) == NULL) {
mtx_unlock(&Giant);
return (EBADF);
}
if (fp->f_type != DTYPE_VNODE) {
mtx_unlock(&Giant);
return (EINVAL);
}
/*
* don't let the descriptor disappear on us if we block
*/
fhold(fp);
/*
* POSIX shared-memory objects are defined to have
* kernel persistence, and are not defined to support
* read(2)/write(2) -- or even open(2). Thus, we can
* use MAP_ASYNC to trade on-disk coherence for speed.
* The shm_open(3) library routine turns on the FPOSIXSHM
* flag to request this behavior.
*/
if (fp->f_flag & FPOSIXSHM)
flags |= MAP_NOSYNC;
vp = (struct vnode *) fp->f_data;
if (vp->v_type != VREG && vp->v_type != VCHR) {
error = EINVAL;
goto done;
}
if (vp->v_type == VREG) {
/*
* Get the proper underlying object
*/
if (VOP_GETVOBJECT(vp, &obj) != 0) {
error = EINVAL;
goto done;
}
origvp = vp;
vp = (struct vnode*)obj->handle;
}
/*
* XXX hack to handle use of /dev/zero to map anon memory (ala
* SunOS).
*/
if ((vp->v_type == VCHR) &&
(vp->v_rdev->si_devsw->d_flags & D_MMAP_ANON)) {
handle = NULL;
maxprot = VM_PROT_ALL;
flags |= MAP_ANON;
pos = 0;
} else {
/*
* cdevs does not provide private mappings of any kind.
*/
/*
* However, for XIG X server to continue to work,
* we should allow the superuser to do it anyway.
* We only allow it at securelevel < 1.
* (Because the XIG X server writes directly to video
* memory via /dev/mem, it should never work at any
* other securelevel.
* XXX this will have to go
*/
if (securelevel >= 1)
disablexworkaround = 1;
else
disablexworkaround = suser(td);
if (vp->v_type == VCHR && disablexworkaround &&
(flags & (MAP_PRIVATE|MAP_COPY))) {
error = EINVAL;
goto done;
}
/*
* Ensure that file and memory protections are
* compatible. Note that we only worry about
* writability if mapping is shared; in this case,
* current and max prot are dictated by the open file.
* XXX use the vnode instead? Problem is: what
* credentials do we use for determination? What if
* proc does a setuid?
*/
maxprot = VM_PROT_EXECUTE; /* ??? */
if (fp->f_flag & FREAD) {
maxprot |= VM_PROT_READ;
} else if (prot & PROT_READ) {
error = EACCES;
goto done;
}
/*
* If we are sharing potential changes (either via
* MAP_SHARED or via the implicit sharing of character
* device mappings), and we are trying to get write
* permission although we opened it without asking
* for it, bail out. Check for superuser, only if
* we're at securelevel < 1, to allow the XIG X server
* to continue to work.
*/
if ((flags & MAP_SHARED) != 0 ||
(vp->v_type == VCHR && disablexworkaround)) {
if ((fp->f_flag & FWRITE) != 0) {
struct vattr va;
if ((error =
VOP_GETATTR(vp, &va,
td->td_ucred, td))) {
goto done;
}
if ((va.va_flags &
(SF_SNAPSHOT|IMMUTABLE|APPEND)) == 0) {
maxprot |= VM_PROT_WRITE;
} else if (prot & PROT_WRITE) {
error = EPERM;
goto done;
}
} else if ((prot & PROT_WRITE) != 0) {
error = EACCES;
goto done;
}
} else {
maxprot |= VM_PROT_WRITE;
}
handle = (void *)vp;
origvp = vp;
}
}
/*
* Do not allow more then a certain number of vm_map_entry structures
* per process. Scale with the number of rforks sharing the map
* to make the limit reasonable for threads.
*/
if (max_proc_mmap &&
vms->vm_map.nentries >= max_proc_mmap * vms->vm_refcnt) {
error = ENOMEM;
goto done;
}
mtx_unlock(&Giant);
error = 0;
if (handle != NULL && VISLOMAC(origvp)) {
lobj.lo_type = LO_TYPE_LVNODE;
lobj.lo_object.vnode = origvp;
if (flags & MAP_SHARED && maxprot & VM_PROT_WRITE &&
!mediate_subject_object("mmap", p, &lobj))
error = EPERM;
if (error == 0 && maxprot & VM_PROT_READ)
error = monitor_read_object(p, &lobj);
}
if (error == 0)
error = vm_mmap(&vms->vm_map, &addr, size, prot, maxprot,
flags, handle, pos);
if (error == 0)
td->td_retval[0] = (register_t) (addr + pageoff);
mtx_lock(&Giant);
done:
if (fp)
fdrop(fp, td);
mtx_unlock(&Giant);
return (error);
}
static void
vm_drop_perms_recurse(struct thread *td, struct vm_map *map, lattr_t *lattr) {
struct vm_map_entry *vme;
for (vme = map->header.next; vme != &map->header; vme = vme->next) {
if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
vm_map_lock_read(vme->object.sub_map);
vm_drop_perms_recurse(td, vme->object.sub_map,
lattr);
vm_map_unlock_read(vme->object.sub_map);
continue;
}
if ((vme->eflags & (MAP_ENTRY_COW | MAP_ENTRY_NOSYNC)) == 0 &&
vme->max_protection & VM_PROT_WRITE) {
vm_object_t object;
vm_ooffset_t offset;
lomac_object_t lobj;
struct vnode *vp;
lattr_t olattr;
offset = vme->offset;
object = vme->object.vm_object;
if (object == NULL)
continue;
while (object->backing_object) {
object = object->backing_object;
offset += object->backing_object_offset;
}
/*
* Regular objects (swap, etc.) inherit from
* their creator. Vnodes inherit from their
* underlying on-disk object.
*/
if (object->type == OBJT_DEVICE)
continue;
if (object->type == OBJT_VNODE) {
vp = lobj.lo_object.vnode = object->handle;
/*
* For the foreseeable future, an OBJT_VNODE
* is always !VISLOMAC().
*/
lobj.lo_type = VISLOMAC(vp) ?
LO_TYPE_LVNODE : LO_TYPE_UVNODE;
} else {
vp = NULL;
lobj.lo_object.vm_object = object;
lobj.lo_type = LO_TYPE_VM_OBJECT;
}
get_object_lattr(&lobj, &olattr);
/*
* Revoke write access only to files with a higher
* level than the process or which have a possibly-
* undeterminable level (interpreted as "lowest").
*/
if (lomac_must_deny(lattr, &olattr))
continue;
vm_map_lock_upgrade(map);
/*
* If it's a private, non-file-backed mapping and
* not mapped anywhere else, we can just take it
* down with us.
*/
if (vp == NULL && object->flags & OBJ_ONEMAPPING) {
olattr.level = lattr->level;
set_object_lattr(&lobj, olattr);
goto downgrade;
}
if ((vme->protection & VM_PROT_WRITE) == 0)
vme->max_protection &= ~VM_PROT_WRITE;
else {
vm_object_reference(object);
if (vp != NULL)
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY,
td);
vm_object_page_clean(object,
OFF_TO_IDX(offset),
OFF_TO_IDX(offset + vme->end - vme->start +
PAGE_MASK),
OBJPC_SYNC);
if (vp != NULL)
VOP_UNLOCK(vp, 0, td);
vm_object_deallocate(object);
vme->eflags |= MAP_ENTRY_COW |
MAP_ENTRY_NEEDS_COPY;
pmap_protect(map->pmap, vme->start, vme->end,
vme->protection & ~VM_PROT_WRITE);
vm_map_simplify_entry(map, vme);
}
downgrade:
vm_map_lock_downgrade(map);
}
}
}
void
kernel_vm_drop_perms(struct thread *td, lattr_t *newlattr) {
struct vm_map *map = &td->td_proc->p_vmspace->vm_map;
mtx_lock(&Giant);
vm_map_lock_read(map);
vm_drop_perms_recurse(td, map, newlattr);
vm_map_unlock_read(map);
mtx_unlock(&Giant);
}
/*
* Take the level of new vm_objects from the parent subject's level.
*/
static void
vm_object_init_lattr(vm_object_t object) {
lomac_object_t lobj;
lattr_t lattr;
get_subject_lattr(curthread->td_proc, &lattr);
lattr.flags = 0;
lobj.lo_type = LO_TYPE_VM_OBJECT;
lobj.lo_object.vm_object = object;
set_object_lattr(&lobj, lattr);
}
#define PGO_ALLOC_REPLACEMENT(n) \
static vm_object_t (*old_pgo_alloc_##n)(void *, vm_ooffset_t, \
vm_prot_t, vm_ooffset_t); \
\
static vm_object_t \
pgo_alloc_##n(void *handle, vm_ooffset_t size, vm_prot_t prot, \
vm_ooffset_t off) { \
vm_object_t newobj = NULL; \
\
newobj = old_pgo_alloc_##n(handle, size, prot, off); \
if (newobj != NULL) \
vm_object_init_lattr(newobj); \
return (newobj); \
}
#define PGO_ALLOC_REPLACE(n) \
do { \
old_pgo_alloc_##n = pagertab[n]->pgo_alloc; \
if (pagertab[n]->pgo_alloc != NULL) \
pagertab[n]->pgo_alloc = pgo_alloc_##n; \
} while (0)
#define PGO_ALLOC_UNREPLACE(n) \
do { \
pagertab[n]->pgo_alloc = old_pgo_alloc_##n; \
} while (0)
PGO_ALLOC_REPLACEMENT(0);
PGO_ALLOC_REPLACEMENT(1);
PGO_ALLOC_REPLACEMENT(2);
PGO_ALLOC_REPLACEMENT(3);
PGO_ALLOC_REPLACEMENT(4);
PGO_ALLOC_REPLACEMENT(5);
extern int npagers;
int
lomac_initialize_vm(void) {
GIANT_REQUIRED;
if (npagers != 6) {
printf("LOMAC: number of pagers %d not expected 6!\n", npagers);
return (EDOM);
}
PGO_ALLOC_REPLACE(0);
PGO_ALLOC_REPLACE(1);
PGO_ALLOC_REPLACE(2);
PGO_ALLOC_REPLACE(3);
PGO_ALLOC_REPLACE(4);
PGO_ALLOC_REPLACE(5);
return (0);
}
int
lomac_uninitialize_vm(void) {
GIANT_REQUIRED;
PGO_ALLOC_UNREPLACE(0);
PGO_ALLOC_UNREPLACE(1);
PGO_ALLOC_UNREPLACE(2);
PGO_ALLOC_UNREPLACE(3);
PGO_ALLOC_UNREPLACE(4);
PGO_ALLOC_UNREPLACE(5);
return (0);
}
