security/mac_priv.c

   1 /*
   2  * Copyright (c) 2010 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*-
  29  * Copyright (c) 2006 nCircle Network Security, Inc.
  30  * Copyright (c) 2009 Robert N. M. Watson
  31  * All rights reserved.
  32  *
  33  * This software was developed by Robert N. M. Watson for the TrustedBSD
  34  * Project under contract to nCircle Network Security, Inc.
  35  *
  36  * This software was developed at the University of Cambridge Computer
  37  * Laboratory with support from a grant from Google, Inc.
  38  *
  39  * Redistribution and use in source and binary forms, with or without
  40  * modification, are permitted provided that the following conditions
  41  * are met:
  42  * 1. Redistributions of source code must retain the above copyright
  43  *    notice, this list of conditions and the following disclaimer.
  44  * 2. Redistributions in binary form must reproduce the above copyright
  45  *    notice, this list of conditions and the following disclaimer in the
  46  *    documentation and/or other materials provided with the distribution.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR, NCIRCLE NETWORK SECURITY,
  52  * INC., OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  53  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  54  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  55  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  56  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  57  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  58  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  59  */
  60
  61 /*
  62  * MAC checks for system privileges.
  63  */
  64
  65 #include <sys/param.h>
  66 #include <sys/kernel.h>
  67
  68 #include <security/mac_internal.h>
  69
  70 /*
  71  * The MAC Framework interacts with kernel privilege checks in two ways: it
  72  * may restrict the granting of privilege to a subject, and it may grant
  73  * additional privileges to the subject.  Policies may implement none, one,
  74  * or both of these entry points.  Restriction of privilege by any policy
  75  * always overrides granting of privilege by any policy or other privilege
  76  * mechanism.  See kern_priv.c:priv_check_cred() for details of the
  77  * composition.
  78  */
  79
  80 /*
  81  * Restrict access to a privilege for a credential.  Return failure if any
  82  * policy denies access.
  83  */
  84 int
  85 mac_priv_check(kauth_cred_t cred, int priv)
  86 {
  87         int error;
  88
  89         if (!mac_cred_check_enforce(cred))
  90                 return 0;
  91
  92         MAC_CHECK(priv_check, cred, priv);
  93
  94         return (error);
  95 }
  96
  97 /*
  98  * Grant access to a privilege for a credential.  Return success if any
  99  * policy grants access.
 100  */
 101 int
 102 mac_priv_grant(kauth_cred_t cred, int priv)
 103 {
 104         int error;
 105
 106         if (!mac_cred_check_enforce(cred))
 107                 return 0;
 108
 109         MAC_GRANT(priv_grant, cred, priv);
 110
 111         return (error);
 112 }