freebsd-dev/sys/dev/mem/memdev.c
Jamie Gritton c71e336230 Add new privileges, PRIV_KMEM_READ and PRIV_KMEM_WRITE, used in opening
/dev/kmem and /dev/mem (in addition to traditional file permission checks).
PRIV_KMEM_READ is different from other PRIV_* checks in that it's allowed
by default.

Reviewed by:	kib, mckusick
2013-07-05 21:31:16 +00:00

117 lines
3.0 KiB
C

/*-
* Copyright (c) 2004 Mark R V Murray
* 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
* in this position and unchanged.
* 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 ``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 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/param.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/memrange.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <machine/memdev.h>
static struct cdev *memdev, *kmemdev;
static struct cdevsw mem_cdevsw = {
.d_version = D_VERSION,
.d_flags = D_MEM|D_NEEDGIANT,
.d_open = memopen,
.d_read = memrw,
.d_write = memrw,
.d_ioctl = memioctl,
.d_mmap = memmmap,
.d_name = "mem",
};
/* ARGSUSED */
int
memopen(struct cdev *dev __unused, int flags, int fmt __unused,
struct thread *td)
{
int error = 0;
if (flags & FREAD)
error = priv_check(td, PRIV_KMEM_READ);
if (flags & FWRITE) {
if (error == 0)
error = priv_check(td, PRIV_KMEM_WRITE);
if (error == 0)
error = securelevel_gt(td->td_ucred, 0);
}
return (error);
}
/* ARGSUSED */
static int
mem_modevent(module_t mod __unused, int type, void *data __unused)
{
switch(type) {
case MOD_LOAD:
if (bootverbose)
printf("mem: <memory>\n");
mem_range_init();
memdev = make_dev(&mem_cdevsw, CDEV_MINOR_MEM,
UID_ROOT, GID_KMEM, 0640, "mem");
kmemdev = make_dev(&mem_cdevsw, CDEV_MINOR_KMEM,
UID_ROOT, GID_KMEM, 0640, "kmem");
break;
case MOD_UNLOAD:
mem_range_destroy();
destroy_dev(memdev);
destroy_dev(kmemdev);
break;
case MOD_SHUTDOWN:
break;
default:
return(EOPNOTSUPP);
}
return (0);
}
DEV_MODULE(mem, mem_modevent, NULL);
MODULE_VERSION(mem, 1);