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 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
38 * are met:
39 * 1. Redistributions of source code must retain the above copyright
40 * notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 * notice, this list of conditions and the following disclaimer in the
43 * documentation and/or other materials provided with the distribution.
44 *
45 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
46 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
47 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
48 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR, NCIRCLE NETWORK SECURITY,
49 * INC., OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
50 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
51 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
52 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
53 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
54 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
55 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56 */
57
58 #include <sys/cdefs.h>
59
60 #include <sys/param.h>
61 #include <sys/kernel.h>
62 #include <sys/priv.h>
63 #include <sys/proc.h>
64 #include <sys/systm.h>
65 #include <sys/kauth.h>
66
67 #if CONFIG_MACF
68 #include <security/mac_framework.h>
69 #endif
70
71 int proc_check_footprint_priv(void);
72
73 /*
74 * Check a credential for privilege. Lots of good reasons to deny privilege;
75 * only a few to grant it.
76 */
77 int
priv_check_cred(kauth_cred_t cred,int priv,int flags)78 priv_check_cred(kauth_cred_t cred, int priv, int flags)
79 {
80 #if !CONFIG_MACF
81 #pragma unused(priv)
82 #endif
83 int error;
84
85 /*
86 * We first evaluate policies that may deny the granting of
87 * privilege unilaterally.
88 */
89 #if CONFIG_MACF
90 error = mac_priv_check(cred, priv);
91 if (error) {
92 goto out;
93 }
94 #endif
95
96 /* Only grant all privileges to root if DEFAULT_UNPRIVELEGED flag is NOT set. */
97 if (!(flags & PRIVCHECK_DEFAULT_UNPRIVILEGED_FLAG)) {
98 /*
99 * Having determined if privilege is restricted by various policies,
100 * now determine if privilege is granted. At this point, any policy
101 * may grant privilege. For now, we allow short-circuit boolean
102 * evaluation, so may not call all policies. Perhaps we should.
103 */
104 if (kauth_cred_getuid(cred) == 0) {
105 error = 0;
106 goto out;
107 }
108 }
109
110 /*
111 * Now check with MAC, if enabled, to see if a policy module grants
112 * privilege.
113 */
114 #if CONFIG_MACF
115 if (mac_priv_grant(cred, priv) == 0) {
116 error = 0;
117 goto out;
118 }
119 #endif
120
121 /*
122 * The default is deny, so if no policies have granted it, reject
123 * with a privilege error here.
124 */
125 error = EPERM;
126 out:
127 return error;
128 }
129
130 int
proc_check_footprint_priv(void)131 proc_check_footprint_priv(void)
132 {
133 return priv_check_cred(kauth_cred_get(), PRIV_VM_FOOTPRINT_LIMIT, 0);
134 }
135