freebsd-skq/sys/security/mac/mac_label.c
rwatson 77ed6e2d1c Modify the MAC Framework so that instead of embedding a (struct label)
in various kernel objects to represent security data, we embed a
(struct label *) pointer, which now references labels allocated using
a UMA zone (mac_label.c).  This allows the size and shape of struct
label to be varied without changing the size and shape of these kernel
objects, which become part of the frozen ABI with 5-STABLE.  This opens
the door for boot-time selection of the number of label slots, and hence
changes to the bound on the number of simultaneous labeled policies
at boot-time instead of compile-time.  This also makes it easier to
embed label references in new objects as required for locking/caching
with fine-grained network stack locking, such as inpcb structures.

This change also moves us further in the direction of hiding the
structure of kernel objects from MAC policy modules, not to mention
dramatically reducing the number of '&' symbols appearing in both the
MAC Framework and MAC policy modules, and improving readability.

While this results in minimal performance change with MAC enabled, it
will observably shrink the size of a number of critical kernel data
structures for the !MAC case, and should have a small (but measurable)
performance benefit (i.e., struct vnode, struct socket) do to memory
conservation and reduced cost of zeroing memory.

NOTE: Users of MAC must recompile their kernel and all MAC modules as a
result of this change.  Because this is an API change, third party
MAC modules will also need to be updated to make less use of the '&'
symbol.

Suggestions from:	bmilekic
Obtained from:		TrustedBSD Project
Sponsored by:		DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00

98 lines
2.8 KiB
C

/*-
* Copyright (c) 2003 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project in part by Network
* Associates Laboratories, 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.
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/mac.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <vm/uma.h>
#include <security/mac/mac_internal.h>
uma_zone_t zone_label;
static void mac_labelzone_ctor(void *mem, int size, void *arg);
static void mac_labelzone_dtor(void *mem, int size, void *arg);
void
mac_labelzone_init(void)
{
zone_label = uma_zcreate("MAC labels", sizeof(struct label),
mac_labelzone_ctor, mac_labelzone_dtor, NULL, NULL,
UMA_ALIGN_PTR, 0);
}
static void
mac_labelzone_ctor(void *mem, int size, void *arg)
{
struct label *label;
KASSERT(size == sizeof(*label), ("mac_labelzone_ctor: wrong size\n"));
label = mem;
bzero(label, sizeof(*label));
label->l_flags = MAC_FLAG_INITIALIZED;
}
static void
mac_labelzone_dtor(void *mem, int size, void *arg)
{
struct label *label;
KASSERT(size == sizeof(*label), ("mac_labelzone_dtor: wrong size\n"));
label = mem;
#ifdef DIAGNOSTIC
bzero(label, sizeof(*label));
#else
label->l_flags &= ~MAC_FLAG_INITIALIZED;
#endif
}
struct label *
mac_labelzone_alloc(int flags)
{
return (uma_zalloc(zone_label, flags));
}
void
mac_labelzone_free(struct label *label)
{
uma_zfree(zone_label, label);
}