FreeBSD/Linux Kernel Cross Reference
sys/security/mac/mac_priv.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: releng/11.0/sys/security/mac/mac_priv.c 258541 2013-11-25 07:38:45Z attilio $");
    
    #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(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(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);
    }

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