freebsd-dev/sys/security/mac/mac_priv.c
Mateusz Guzik 91061084d1 mac: implement fast path for checks
All checking routines walk a linked list of all modules in order to determine
if given hook is installed. This became a significant problem after mac_ntpd
started being loaded by default.

Implement a way perform checks for select hooks by testing a boolean.

Use it for priv_check and priv_grant, which are constantly called from priv_check.

The real fix would use hotpatching, but the above provides a way to know when
to do it.
2020-02-13 22:19:17 +00:00

96 lines
3.2 KiB
C

/*-
* Copyright (c) 2006 nCircle Network Security, Inc.
* Copyright (c) 2009 Robert N. M. Watson
* All rights reserved.
*
* This software was developed by Robert N. M. Watson for the TrustedBSD
* Project under contract to nCircle Network Security, Inc.
*
* This software was developed at the University of Cambridge Computer
* Laboratory with support from a grant from Google, 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.
*
* 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, NCIRCLE NETWORK SECURITY,
* INC., 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.
*/
/*
* MAC checks for system privileges.
*/
#include "sys/cdefs.h"
__FBSDID("$FreeBSD$");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/priv.h>
#include <sys/sdt.h>
#include <sys/module.h>
#include <security/mac/mac_framework.h>
#include <security/mac/mac_internal.h>
#include <security/mac/mac_policy.h>
/*
* The MAC Framework interacts with kernel privilege checks in two ways: it
* may restrict the granting of privilege to a subject, and it may grant
* additional privileges to the subject. Policies may implement none, one,
* or both of these entry points. Restriction of privilege by any policy
* always overrides granting of privilege by any policy or other privilege
* mechanism. See kern_priv.c:priv_check_cred() for details of the
* composition.
*/
MAC_CHECK_PROBE_DEFINE2(priv_check, "struct ucred *", "int");
/*
* Restrict access to a privilege for a credential. Return failure if any
* policy denies access.
*/
int
mac_priv_check_impl(struct ucred *cred, int priv)
{
int error;
MAC_POLICY_CHECK_NOSLEEP(priv_check, cred, priv);
MAC_CHECK_PROBE2(priv_check, error, cred, priv);
return (error);
}
MAC_GRANT_PROBE_DEFINE2(priv_grant, "struct ucred *", "int");
/*
* Grant access to a privilege for a credential. Return success if any
* policy grants access.
*/
int
mac_priv_grant_impl(struct ucred *cred, int priv)
{
int error;
MAC_POLICY_GRANT_NOSLEEP(priv_grant, cred, priv);
MAC_GRANT_PROBE2(priv_grant, error, cred, priv);
return (error);
}